Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

39 files changed, 49463 insertions, 0 deletions

diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile
new file mode 100644
index 0000000000..976092b7bd
--- /dev/null
+++ b/kernel/sched/Makefile
@@ -0,0 +1,34 @@
+# SPDX-License-Identifier: GPL-2.0
+
+# The compilers are complaining about unused variables inside an if(0) scope
+# block. This is daft, shut them up.
+ccflags-y += $(call cc-disable-warning, unused-but-set-variable)
+
+# These files are disabled because they produce non-interesting flaky coverage
+# that is not a function of syscall inputs. E.g. involuntary context switches.
+KCOV_INSTRUMENT := n
+
+# Disable KCSAN to avoid excessive noise and performance degradation. To avoid
+# false positives ensure barriers implied by sched functions are instrumented.
+KCSAN_SANITIZE := n
+KCSAN_INSTRUMENT_BARRIERS := y
+
+ifneq ($(CONFIG_SCHED_OMIT_FRAME_POINTER),y)
+# According to Alan Modra <alan@linuxcare.com.au>, the -fno-omit-frame-pointer is
+# needed for x86 only.  Why this used to be enabled for all architectures is beyond
+# me.  I suspect most platforms don't need this, but until we know that for sure
+# I turn this off for IA-64 only.  Andreas Schwab says it's also needed on m68k
+# to get a correct value for the wait-channel (WCHAN in ps). --davidm
+CFLAGS_core.o := $(PROFILING) -fno-omit-frame-pointer
+endif
+
+#
+# Build efficiency:
+#
+# These compilation units have roughly the same size and complexity - so their
+# build parallelizes well and finishes roughly at once:
+#
+obj-y += core.o
+obj-y += fair.o
+obj-y += build_policy.o
+obj-y += build_utility.o
diff --git a/kernel/sched/autogroup.c b/kernel/sched/autogroup.c
new file mode 100644
index 0000000000..991fc90025
--- /dev/null
+++ b/kernel/sched/autogroup.c
@@ -0,0 +1,291 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Auto-group scheduling implementation:
+ */
+
+unsigned int __read_mostly sysctl_sched_autogroup_enabled = 1;
+static struct autogroup autogroup_default;
+static atomic_t autogroup_seq_nr;
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table sched_autogroup_sysctls[] = {
+	{
+		.procname       = "sched_autogroup_enabled",
+		.data           = &sysctl_sched_autogroup_enabled,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = proc_dointvec_minmax,
+		.extra1         = SYSCTL_ZERO,
+		.extra2         = SYSCTL_ONE,
+	},
+	{}
+};
+
+static void __init sched_autogroup_sysctl_init(void)
+{
+	register_sysctl_init("kernel", sched_autogroup_sysctls);
+}
+#else
+#define sched_autogroup_sysctl_init() do { } while (0)
+#endif
+
+void __init autogroup_init(struct task_struct *init_task)
+{
+	autogroup_default.tg = &root_task_group;
+	kref_init(&autogroup_default.kref);
+	init_rwsem(&autogroup_default.lock);
+	init_task->signal->autogroup = &autogroup_default;
+	sched_autogroup_sysctl_init();
+}
+
+void autogroup_free(struct task_group *tg)
+{
+	kfree(tg->autogroup);
+}
+
+static inline void autogroup_destroy(struct kref *kref)
+{
+	struct autogroup *ag = container_of(kref, struct autogroup, kref);
+
+#ifdef CONFIG_RT_GROUP_SCHED
+	/* We've redirected RT tasks to the root task group... */
+	ag->tg->rt_se = NULL;
+	ag->tg->rt_rq = NULL;
+#endif
+	sched_release_group(ag->tg);
+	sched_destroy_group(ag->tg);
+}
+
+static inline void autogroup_kref_put(struct autogroup *ag)
+{
+	kref_put(&ag->kref, autogroup_destroy);
+}
+
+static inline struct autogroup *autogroup_kref_get(struct autogroup *ag)
+{
+	kref_get(&ag->kref);
+	return ag;
+}
+
+static inline struct autogroup *autogroup_task_get(struct task_struct *p)
+{
+	struct autogroup *ag;
+	unsigned long flags;
+
+	if (!lock_task_sighand(p, &flags))
+		return autogroup_kref_get(&autogroup_default);
+
+	ag = autogroup_kref_get(p->signal->autogroup);
+	unlock_task_sighand(p, &flags);
+
+	return ag;
+}
+
+static inline struct autogroup *autogroup_create(void)
+{
+	struct autogroup *ag = kzalloc(sizeof(*ag), GFP_KERNEL);
+	struct task_group *tg;
+
+	if (!ag)
+		goto out_fail;
+
+	tg = sched_create_group(&root_task_group);
+	if (IS_ERR(tg))
+		goto out_free;
+
+	kref_init(&ag->kref);
+	init_rwsem(&ag->lock);
+	ag->id = atomic_inc_return(&autogroup_seq_nr);
+	ag->tg = tg;
+#ifdef CONFIG_RT_GROUP_SCHED
+	/*
+	 * Autogroup RT tasks are redirected to the root task group
+	 * so we don't have to move tasks around upon policy change,
+	 * or flail around trying to allocate bandwidth on the fly.
+	 * A bandwidth exception in __sched_setscheduler() allows
+	 * the policy change to proceed.
+	 */
+	free_rt_sched_group(tg);
+	tg->rt_se = root_task_group.rt_se;
+	tg->rt_rq = root_task_group.rt_rq;
+#endif
+	tg->autogroup = ag;
+
+	sched_online_group(tg, &root_task_group);
+	return ag;
+
+out_free:
+	kfree(ag);
+out_fail:
+	if (printk_ratelimit()) {
+		printk(KERN_WARNING "autogroup_create: %s failure.\n",
+			ag ? "sched_create_group()" : "kzalloc()");
+	}
+
+	return autogroup_kref_get(&autogroup_default);
+}
+
+bool task_wants_autogroup(struct task_struct *p, struct task_group *tg)
+{
+	if (tg != &root_task_group)
+		return false;
+	/*
+	 * If we race with autogroup_move_group() the caller can use the old
+	 * value of signal->autogroup but in this case sched_move_task() will
+	 * be called again before autogroup_kref_put().
+	 *
+	 * However, there is no way sched_autogroup_exit_task() could tell us
+	 * to avoid autogroup->tg, so we abuse PF_EXITING flag for this case.
+	 */
+	if (p->flags & PF_EXITING)
+		return false;
+
+	return true;
+}
+
+void sched_autogroup_exit_task(struct task_struct *p)
+{
+	/*
+	 * We are going to call exit_notify() and autogroup_move_group() can't
+	 * see this thread after that: we can no longer use signal->autogroup.
+	 * See the PF_EXITING check in task_wants_autogroup().
+	 */
+	sched_move_task(p);
+}
+
+static void
+autogroup_move_group(struct task_struct *p, struct autogroup *ag)
+{
+	struct autogroup *prev;
+	struct task_struct *t;
+	unsigned long flags;
+
+	if (WARN_ON_ONCE(!lock_task_sighand(p, &flags)))
+		return;
+
+	prev = p->signal->autogroup;
+	if (prev == ag) {
+		unlock_task_sighand(p, &flags);
+		return;
+	}
+
+	p->signal->autogroup = autogroup_kref_get(ag);
+	/*
+	 * We can't avoid sched_move_task() after we changed signal->autogroup,
+	 * this process can already run with task_group() == prev->tg or we can
+	 * race with cgroup code which can read autogroup = prev under rq->lock.
+	 * In the latter case for_each_thread() can not miss a migrating thread,
+	 * cpu_cgroup_attach() must not be possible after cgroup_exit() and it
+	 * can't be removed from thread list, we hold ->siglock.
+	 *
+	 * If an exiting thread was already removed from thread list we rely on
+	 * sched_autogroup_exit_task().
+	 */
+	for_each_thread(p, t)
+		sched_move_task(t);
+
+	unlock_task_sighand(p, &flags);
+	autogroup_kref_put(prev);
+}
+
+/* Allocates GFP_KERNEL, cannot be called under any spinlock: */
+void sched_autogroup_create_attach(struct task_struct *p)
+{
+	struct autogroup *ag = autogroup_create();
+
+	autogroup_move_group(p, ag);
+
+	/* Drop extra reference added by autogroup_create(): */
+	autogroup_kref_put(ag);
+}
+EXPORT_SYMBOL(sched_autogroup_create_attach);
+
+/* Cannot be called under siglock. Currently has no users: */
+void sched_autogroup_detach(struct task_struct *p)
+{
+	autogroup_move_group(p, &autogroup_default);
+}
+EXPORT_SYMBOL(sched_autogroup_detach);
+
+void sched_autogroup_fork(struct signal_struct *sig)
+{
+	sig->autogroup = autogroup_task_get(current);
+}
+
+void sched_autogroup_exit(struct signal_struct *sig)
+{
+	autogroup_kref_put(sig->autogroup);
+}
+
+static int __init setup_autogroup(char *str)
+{
+	sysctl_sched_autogroup_enabled = 0;
+
+	return 1;
+}
+__setup("noautogroup", setup_autogroup);
+
+#ifdef CONFIG_PROC_FS
+
+int proc_sched_autogroup_set_nice(struct task_struct *p, int nice)
+{
+	static unsigned long next = INITIAL_JIFFIES;
+	struct autogroup *ag;
+	unsigned long shares;
+	int err, idx;
+
+	if (nice < MIN_NICE || nice > MAX_NICE)
+		return -EINVAL;
+
+	err = security_task_setnice(current, nice);
+	if (err)
+		return err;
+
+	if (nice < 0 && !can_nice(current, nice))
+		return -EPERM;
+
+	/* This is a heavy operation, taking global locks.. */
+	if (!capable(CAP_SYS_ADMIN) && time_before(jiffies, next))
+		return -EAGAIN;
+
+	next = HZ / 10 + jiffies;
+	ag = autogroup_task_get(p);
+
+	idx = array_index_nospec(nice + 20, 40);
+	shares = scale_load(sched_prio_to_weight[idx]);
+
+	down_write(&ag->lock);
+	err = sched_group_set_shares(ag->tg, shares);
+	if (!err)
+		ag->nice = nice;
+	up_write(&ag->lock);
+
+	autogroup_kref_put(ag);
+
+	return err;
+}
+
+void proc_sched_autogroup_show_task(struct task_struct *p, struct seq_file *m)
+{
+	struct autogroup *ag = autogroup_task_get(p);
+
+	if (!task_group_is_autogroup(ag->tg))
+		goto out;
+
+	down_read(&ag->lock);
+	seq_printf(m, "/autogroup-%ld nice %d\n", ag->id, ag->nice);
+	up_read(&ag->lock);
+
+out:
+	autogroup_kref_put(ag);
+}
+#endif /* CONFIG_PROC_FS */
+
+int autogroup_path(struct task_group *tg, char *buf, int buflen)
+{
+	if (!task_group_is_autogroup(tg))
+		return 0;
+
+	return snprintf(buf, buflen, "%s-%ld", "/autogroup", tg->autogroup->id);
+}
diff --git a/kernel/sched/autogroup.h b/kernel/sched/autogroup.h
new file mode 100644
index 0000000000..90d69f2c5e
--- /dev/null
+++ b/kernel/sched/autogroup.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _KERNEL_SCHED_AUTOGROUP_H
+#define _KERNEL_SCHED_AUTOGROUP_H
+
+#ifdef CONFIG_SCHED_AUTOGROUP
+
+struct autogroup {
+	/*
+	 * Reference doesn't mean how many threads attach to this
+	 * autogroup now. It just stands for the number of tasks
+	 * which could use this autogroup.
+	 */
+	struct kref		kref;
+	struct task_group	*tg;
+	struct rw_semaphore	lock;
+	unsigned long		id;
+	int			nice;
+};
+
+extern void autogroup_init(struct task_struct *init_task);
+extern void autogroup_free(struct task_group *tg);
+
+static inline bool task_group_is_autogroup(struct task_group *tg)
+{
+	return !!tg->autogroup;
+}
+
+extern bool task_wants_autogroup(struct task_struct *p, struct task_group *tg);
+
+static inline struct task_group *
+autogroup_task_group(struct task_struct *p, struct task_group *tg)
+{
+	extern unsigned int sysctl_sched_autogroup_enabled;
+	int enabled = READ_ONCE(sysctl_sched_autogroup_enabled);
+
+	if (enabled && task_wants_autogroup(p, tg))
+		return p->signal->autogroup->tg;
+
+	return tg;
+}
+
+extern int autogroup_path(struct task_group *tg, char *buf, int buflen);
+
+#else /* !CONFIG_SCHED_AUTOGROUP */
+
+static inline void autogroup_init(struct task_struct *init_task) {  }
+static inline void autogroup_free(struct task_group *tg) { }
+static inline bool task_group_is_autogroup(struct task_group *tg)
+{
+	return 0;
+}
+
+static inline struct task_group *
+autogroup_task_group(struct task_struct *p, struct task_group *tg)
+{
+	return tg;
+}
+
+static inline int autogroup_path(struct task_group *tg, char *buf, int buflen)
+{
+	return 0;
+}
+
+#endif /* CONFIG_SCHED_AUTOGROUP */
+
+#endif /* _KERNEL_SCHED_AUTOGROUP_H */
diff --git a/kernel/sched/build_policy.c b/kernel/sched/build_policy.c
new file mode 100644
index 0000000000..d9dc9ab377
--- /dev/null
+++ b/kernel/sched/build_policy.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * These are the scheduling policy related scheduler files, built
+ * in a single compilation unit for build efficiency reasons.
+ *
+ * ( Incidentally, the size of the compilation unit is roughly
+ *   comparable to core.c and fair.c, the other two big
+ *   compilation units. This helps balance build time, while
+ *   coalescing source files to amortize header inclusion
+ *   cost. )
+ *
+ * core.c and fair.c are built separately.
+ */
+
+/* Headers: */
+#include <linux/sched/clock.h>
+#include <linux/sched/cputime.h>
+#include <linux/sched/hotplug.h>
+#include <linux/sched/posix-timers.h>
+#include <linux/sched/rt.h>
+
+#include <linux/cpuidle.h>
+#include <linux/jiffies.h>
+#include <linux/livepatch.h>
+#include <linux/psi.h>
+#include <linux/seqlock_api.h>
+#include <linux/slab.h>
+#include <linux/suspend.h>
+#include <linux/tsacct_kern.h>
+#include <linux/vtime.h>
+
+#include <uapi/linux/sched/types.h>
+
+#include "sched.h"
+#include "smp.h"
+
+#include "autogroup.h"
+#include "stats.h"
+#include "pelt.h"
+
+/* Source code modules: */
+
+#include "idle.c"
+
+#include "rt.c"
+
+#ifdef CONFIG_SMP
+# include "cpudeadline.c"
+# include "pelt.c"
+#endif
+
+#include "cputime.c"
+#include "deadline.c"
+
diff --git a/kernel/sched/build_utility.c b/kernel/sched/build_utility.c
new file mode 100644
index 0000000000..99bdd96f45
--- /dev/null
+++ b/kernel/sched/build_utility.c
@@ -0,0 +1,110 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * These are various utility functions of the scheduler,
+ * built in a single compilation unit for build efficiency reasons.
+ *
+ * ( Incidentally, the size of the compilation unit is roughly
+ *   comparable to core.c, fair.c, smp.c and policy.c, the other
+ *   big compilation units. This helps balance build time, while
+ *   coalescing source files to amortize header inclusion
+ *   cost. )
+ */
+#include <linux/sched/clock.h>
+#include <linux/sched/cputime.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/isolation.h>
+#include <linux/sched/loadavg.h>
+#include <linux/sched/nohz.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/rseq_api.h>
+#include <linux/sched/task_stack.h>
+
+#include <linux/cpufreq.h>
+#include <linux/cpumask_api.h>
+#include <linux/cpuset.h>
+#include <linux/ctype.h>
+#include <linux/debugfs.h>
+#include <linux/energy_model.h>
+#include <linux/hashtable_api.h>
+#include <linux/irq.h>
+#include <linux/kobject_api.h>
+#include <linux/membarrier.h>
+#include <linux/mempolicy.h>
+#include <linux/nmi.h>
+#include <linux/nospec.h>
+#include <linux/proc_fs.h>
+#include <linux/psi.h>
+#include <linux/psi.h>
+#include <linux/ptrace_api.h>
+#include <linux/sched_clock.h>
+#include <linux/security.h>
+#include <linux/spinlock_api.h>
+#include <linux/swait_api.h>
+#include <linux/timex.h>
+#include <linux/utsname.h>
+#include <linux/wait_api.h>
+#include <linux/workqueue_api.h>
+
+#include <uapi/linux/prctl.h>
+#include <uapi/linux/sched/types.h>
+
+#include <asm/switch_to.h>
+
+#include "sched.h"
+#include "sched-pelt.h"
+#include "stats.h"
+#include "autogroup.h"
+
+#include "clock.c"
+
+#ifdef CONFIG_CGROUP_CPUACCT
+# include "cpuacct.c"
+#endif
+
+#ifdef CONFIG_CPU_FREQ
+# include "cpufreq.c"
+#endif
+
+#ifdef CONFIG_CPU_FREQ_GOV_SCHEDUTIL
+# include "cpufreq_schedutil.c"
+#endif
+
+#ifdef CONFIG_SCHED_DEBUG
+# include "debug.c"
+#endif
+
+#ifdef CONFIG_SCHEDSTATS
+# include "stats.c"
+#endif
+
+#include "loadavg.c"
+#include "completion.c"
+#include "swait.c"
+#include "wait_bit.c"
+#include "wait.c"
+
+#ifdef CONFIG_SMP
+# include "cpupri.c"
+# include "stop_task.c"
+# include "topology.c"
+#endif
+
+#ifdef CONFIG_SCHED_CORE
+# include "core_sched.c"
+#endif
+
+#ifdef CONFIG_PSI
+# include "psi.c"
+#endif
+
+#ifdef CONFIG_MEMBARRIER
+# include "membarrier.c"
+#endif
+
+#ifdef CONFIG_CPU_ISOLATION
+# include "isolation.c"
+#endif
+
+#ifdef CONFIG_SCHED_AUTOGROUP
+# include "autogroup.c"
+#endif
diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c
new file mode 100644
index 0000000000..3c6193de9c
--- /dev/null
+++ b/kernel/sched/clock.c
@@ -0,0 +1,505 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * sched_clock() for unstable CPU clocks
+ *
+ *  Copyright (C) 2008 Red Hat, Inc., Peter Zijlstra
+ *
+ *  Updates and enhancements:
+ *    Copyright (C) 2008 Red Hat, Inc. Steven Rostedt <srostedt@redhat.com>
+ *
+ * Based on code by:
+ *   Ingo Molnar <mingo@redhat.com>
+ *   Guillaume Chazarain <guichaz@gmail.com>
+ *
+ *
+ * What this file implements:
+ *
+ * cpu_clock(i) provides a fast (execution time) high resolution
+ * clock with bounded drift between CPUs. The value of cpu_clock(i)
+ * is monotonic for constant i. The timestamp returned is in nanoseconds.
+ *
+ * ######################### BIG FAT WARNING ##########################
+ * # when comparing cpu_clock(i) to cpu_clock(j) for i != j, time can #
+ * # go backwards !!                                                  #
+ * ####################################################################
+ *
+ * There is no strict promise about the base, although it tends to start
+ * at 0 on boot (but people really shouldn't rely on that).
+ *
+ * cpu_clock(i)       -- can be used from any context, including NMI.
+ * local_clock()      -- is cpu_clock() on the current CPU.
+ *
+ * sched_clock_cpu(i)
+ *
+ * How it is implemented:
+ *
+ * The implementation either uses sched_clock() when
+ * !CONFIG_HAVE_UNSTABLE_SCHED_CLOCK, which means in that case the
+ * sched_clock() is assumed to provide these properties (mostly it means
+ * the architecture provides a globally synchronized highres time source).
+ *
+ * Otherwise it tries to create a semi stable clock from a mixture of other
+ * clocks, including:
+ *
+ *  - GTOD (clock monotonic)
+ *  - sched_clock()
+ *  - explicit idle events
+ *
+ * We use GTOD as base and use sched_clock() deltas to improve resolution. The
+ * deltas are filtered to provide monotonicity and keeping it within an
+ * expected window.
+ *
+ * Furthermore, explicit sleep and wakeup hooks allow us to account for time
+ * that is otherwise invisible (TSC gets stopped).
+ *
+ */
+
+/*
+ * Scheduler clock - returns current time in nanosec units.
+ * This is default implementation.
+ * Architectures and sub-architectures can override this.
+ */
+notrace unsigned long long __weak sched_clock(void)
+{
+	return (unsigned long long)(jiffies - INITIAL_JIFFIES)
+					* (NSEC_PER_SEC / HZ);
+}
+EXPORT_SYMBOL_GPL(sched_clock);
+
+static DEFINE_STATIC_KEY_FALSE(sched_clock_running);
+
+#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
+/*
+ * We must start with !__sched_clock_stable because the unstable -> stable
+ * transition is accurate, while the stable -> unstable transition is not.
+ *
+ * Similarly we start with __sched_clock_stable_early, thereby assuming we
+ * will become stable, such that there's only a single 1 -> 0 transition.
+ */
+static DEFINE_STATIC_KEY_FALSE(__sched_clock_stable);
+static int __sched_clock_stable_early = 1;
+
+/*
+ * We want: ktime_get_ns() + __gtod_offset == sched_clock() + __sched_clock_offset
+ */
+__read_mostly u64 __sched_clock_offset;
+static __read_mostly u64 __gtod_offset;
+
+struct sched_clock_data {
+	u64			tick_raw;
+	u64			tick_gtod;
+	u64			clock;
+};
+
+static DEFINE_PER_CPU_SHARED_ALIGNED(struct sched_clock_data, sched_clock_data);
+
+static __always_inline struct sched_clock_data *this_scd(void)
+{
+	return this_cpu_ptr(&sched_clock_data);
+}
+
+notrace static inline struct sched_clock_data *cpu_sdc(int cpu)
+{
+	return &per_cpu(sched_clock_data, cpu);
+}
+
+notrace int sched_clock_stable(void)
+{
+	return static_branch_likely(&__sched_clock_stable);
+}
+
+notrace static void __scd_stamp(struct sched_clock_data *scd)
+{
+	scd->tick_gtod = ktime_get_ns();
+	scd->tick_raw = sched_clock();
+}
+
+notrace static void __set_sched_clock_stable(void)
+{
+	struct sched_clock_data *scd;
+
+	/*
+	 * Since we're still unstable and the tick is already running, we have
+	 * to disable IRQs in order to get a consistent scd->tick* reading.
+	 */
+	local_irq_disable();
+	scd = this_scd();
+	/*
+	 * Attempt to make the (initial) unstable->stable transition continuous.
+	 */
+	__sched_clock_offset = (scd->tick_gtod + __gtod_offset) - (scd->tick_raw);
+	local_irq_enable();
+
+	printk(KERN_INFO "sched_clock: Marking stable (%lld, %lld)->(%lld, %lld)\n",
+			scd->tick_gtod, __gtod_offset,
+			scd->tick_raw,  __sched_clock_offset);
+
+	static_branch_enable(&__sched_clock_stable);
+	tick_dep_clear(TICK_DEP_BIT_CLOCK_UNSTABLE);
+}
+
+/*
+ * If we ever get here, we're screwed, because we found out -- typically after
+ * the fact -- that TSC wasn't good. This means all our clocksources (including
+ * ktime) could have reported wrong values.
+ *
+ * What we do here is an attempt to fix up and continue sort of where we left
+ * off in a coherent manner.
+ *
+ * The only way to fully avoid random clock jumps is to boot with:
+ * "tsc=unstable".
+ */
+notrace static void __sched_clock_work(struct work_struct *work)
+{
+	struct sched_clock_data *scd;
+	int cpu;
+
+	/* take a current timestamp and set 'now' */
+	preempt_disable();
+	scd = this_scd();
+	__scd_stamp(scd);
+	scd->clock = scd->tick_gtod + __gtod_offset;
+	preempt_enable();
+
+	/* clone to all CPUs */
+	for_each_possible_cpu(cpu)
+		per_cpu(sched_clock_data, cpu) = *scd;
+
+	printk(KERN_WARNING "TSC found unstable after boot, most likely due to broken BIOS. Use 'tsc=unstable'.\n");
+	printk(KERN_INFO "sched_clock: Marking unstable (%lld, %lld)<-(%lld, %lld)\n",
+			scd->tick_gtod, __gtod_offset,
+			scd->tick_raw,  __sched_clock_offset);
+
+	static_branch_disable(&__sched_clock_stable);
+}
+
+static DECLARE_WORK(sched_clock_work, __sched_clock_work);
+
+notrace static void __clear_sched_clock_stable(void)
+{
+	if (!sched_clock_stable())
+		return;
+
+	tick_dep_set(TICK_DEP_BIT_CLOCK_UNSTABLE);
+	schedule_work(&sched_clock_work);
+}
+
+notrace void clear_sched_clock_stable(void)
+{
+	__sched_clock_stable_early = 0;
+
+	smp_mb(); /* matches sched_clock_init_late() */
+
+	if (static_key_count(&sched_clock_running.key) == 2)
+		__clear_sched_clock_stable();
+}
+
+notrace static void __sched_clock_gtod_offset(void)
+{
+	struct sched_clock_data *scd = this_scd();
+
+	__scd_stamp(scd);
+	__gtod_offset = (scd->tick_raw + __sched_clock_offset) - scd->tick_gtod;
+}
+
+void __init sched_clock_init(void)
+{
+	/*
+	 * Set __gtod_offset such that once we mark sched_clock_running,
+	 * sched_clock_tick() continues where sched_clock() left off.
+	 *
+	 * Even if TSC is buggered, we're still UP at this point so it
+	 * can't really be out of sync.
+	 */
+	local_irq_disable();
+	__sched_clock_gtod_offset();
+	local_irq_enable();
+
+	static_branch_inc(&sched_clock_running);
+}
+/*
+ * We run this as late_initcall() such that it runs after all built-in drivers,
+ * notably: acpi_processor and intel_idle, which can mark the TSC as unstable.
+ */
+static int __init sched_clock_init_late(void)
+{
+	static_branch_inc(&sched_clock_running);
+	/*
+	 * Ensure that it is impossible to not do a static_key update.
+	 *
+	 * Either {set,clear}_sched_clock_stable() must see sched_clock_running
+	 * and do the update, or we must see their __sched_clock_stable_early
+	 * and do the update, or both.
+	 */
+	smp_mb(); /* matches {set,clear}_sched_clock_stable() */
+
+	if (__sched_clock_stable_early)
+		__set_sched_clock_stable();
+
+	return 0;
+}
+late_initcall(sched_clock_init_late);
+
+/*
+ * min, max except they take wrapping into account
+ */
+
+static __always_inline u64 wrap_min(u64 x, u64 y)
+{
+	return (s64)(x - y) < 0 ? x : y;
+}
+
+static __always_inline u64 wrap_max(u64 x, u64 y)
+{
+	return (s64)(x - y) > 0 ? x : y;
+}
+
+/*
+ * update the percpu scd from the raw @now value
+ *
+ *  - filter out backward motion
+ *  - use the GTOD tick value to create a window to filter crazy TSC values
+ */
+static __always_inline u64 sched_clock_local(struct sched_clock_data *scd)
+{
+	u64 now, clock, old_clock, min_clock, max_clock, gtod;
+	s64 delta;
+
+again:
+	now = sched_clock_noinstr();
+	delta = now - scd->tick_raw;
+	if (unlikely(delta < 0))
+		delta = 0;
+
+	old_clock = scd->clock;
+
+	/*
+	 * scd->clock = clamp(scd->tick_gtod + delta,
+	 *		      max(scd->tick_gtod, scd->clock),
+	 *		      scd->tick_gtod + TICK_NSEC);
+	 */
+
+	gtod = scd->tick_gtod + __gtod_offset;
+	clock = gtod + delta;
+	min_clock = wrap_max(gtod, old_clock);
+	max_clock = wrap_max(old_clock, gtod + TICK_NSEC);
+
+	clock = wrap_max(clock, min_clock);
+	clock = wrap_min(clock, max_clock);
+
+	if (!raw_try_cmpxchg64(&scd->clock, &old_clock, clock))
+		goto again;
+
+	return clock;
+}
+
+noinstr u64 local_clock_noinstr(void)
+{
+	u64 clock;
+
+	if (static_branch_likely(&__sched_clock_stable))
+		return sched_clock_noinstr() + __sched_clock_offset;
+
+	if (!static_branch_likely(&sched_clock_running))
+		return sched_clock_noinstr();
+
+	clock = sched_clock_local(this_scd());
+
+	return clock;
+}
+
+u64 local_clock(void)
+{
+	u64 now;
+	preempt_disable_notrace();
+	now = local_clock_noinstr();
+	preempt_enable_notrace();
+	return now;
+}
+EXPORT_SYMBOL_GPL(local_clock);
+
+static notrace u64 sched_clock_remote(struct sched_clock_data *scd)
+{
+	struct sched_clock_data *my_scd = this_scd();
+	u64 this_clock, remote_clock;
+	u64 *ptr, old_val, val;
+
+#if BITS_PER_LONG != 64
+again:
+	/*
+	 * Careful here: The local and the remote clock values need to
+	 * be read out atomic as we need to compare the values and
+	 * then update either the local or the remote side. So the
+	 * cmpxchg64 below only protects one readout.
+	 *
+	 * We must reread via sched_clock_local() in the retry case on
+	 * 32-bit kernels as an NMI could use sched_clock_local() via the
+	 * tracer and hit between the readout of
+	 * the low 32-bit and the high 32-bit portion.
+	 */
+	this_clock = sched_clock_local(my_scd);
+	/*
+	 * We must enforce atomic readout on 32-bit, otherwise the
+	 * update on the remote CPU can hit inbetween the readout of
+	 * the low 32-bit and the high 32-bit portion.
+	 */
+	remote_clock = cmpxchg64(&scd->clock, 0, 0);
+#else
+	/*
+	 * On 64-bit kernels the read of [my]scd->clock is atomic versus the
+	 * update, so we can avoid the above 32-bit dance.
+	 */
+	sched_clock_local(my_scd);
+again:
+	this_clock = my_scd->clock;
+	remote_clock = scd->clock;
+#endif
+
+	/*
+	 * Use the opportunity that we have both locks
+	 * taken to couple the two clocks: we take the
+	 * larger time as the latest time for both
+	 * runqueues. (this creates monotonic movement)
+	 */
+	if (likely((s64)(remote_clock - this_clock) < 0)) {
+		ptr = &scd->clock;
+		old_val = remote_clock;
+		val = this_clock;
+	} else {
+		/*
+		 * Should be rare, but possible:
+		 */
+		ptr = &my_scd->clock;
+		old_val = this_clock;
+		val = remote_clock;
+	}
+
+	if (!try_cmpxchg64(ptr, &old_val, val))
+		goto again;
+
+	return val;
+}
+
+/*
+ * Similar to cpu_clock(), but requires local IRQs to be disabled.
+ *
+ * See cpu_clock().
+ */
+notrace u64 sched_clock_cpu(int cpu)
+{
+	struct sched_clock_data *scd;
+	u64 clock;
+
+	if (sched_clock_stable())
+		return sched_clock() + __sched_clock_offset;
+
+	if (!static_branch_likely(&sched_clock_running))
+		return sched_clock();
+
+	preempt_disable_notrace();
+	scd = cpu_sdc(cpu);
+
+	if (cpu != smp_processor_id())
+		clock = sched_clock_remote(scd);
+	else
+		clock = sched_clock_local(scd);
+	preempt_enable_notrace();
+
+	return clock;
+}
+EXPORT_SYMBOL_GPL(sched_clock_cpu);
+
+notrace void sched_clock_tick(void)
+{
+	struct sched_clock_data *scd;
+
+	if (sched_clock_stable())
+		return;
+
+	if (!static_branch_likely(&sched_clock_running))
+		return;
+
+	lockdep_assert_irqs_disabled();
+
+	scd = this_scd();
+	__scd_stamp(scd);
+	sched_clock_local(scd);
+}
+
+notrace void sched_clock_tick_stable(void)
+{
+	if (!sched_clock_stable())
+		return;
+
+	/*
+	 * Called under watchdog_lock.
+	 *
+	 * The watchdog just found this TSC to (still) be stable, so now is a
+	 * good moment to update our __gtod_offset. Because once we find the
+	 * TSC to be unstable, any computation will be computing crap.
+	 */
+	local_irq_disable();
+	__sched_clock_gtod_offset();
+	local_irq_enable();
+}
+
+/*
+ * We are going deep-idle (irqs are disabled):
+ */
+notrace void sched_clock_idle_sleep_event(void)
+{
+	sched_clock_cpu(smp_processor_id());
+}
+EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event);
+
+/*
+ * We just idled; resync with ktime.
+ */
+notrace void sched_clock_idle_wakeup_event(void)
+{
+	unsigned long flags;
+
+	if (sched_clock_stable())
+		return;
+
+	if (unlikely(timekeeping_suspended))
+		return;
+
+	local_irq_save(flags);
+	sched_clock_tick();
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event);
+
+#else /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
+
+void __init sched_clock_init(void)
+{
+	static_branch_inc(&sched_clock_running);
+	local_irq_disable();
+	generic_sched_clock_init();
+	local_irq_enable();
+}
+
+notrace u64 sched_clock_cpu(int cpu)
+{
+	if (!static_branch_likely(&sched_clock_running))
+		return 0;
+
+	return sched_clock();
+}
+
+#endif /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
+
+/*
+ * Running clock - returns the time that has elapsed while a guest has been
+ * running.
+ * On a guest this value should be local_clock minus the time the guest was
+ * suspended by the hypervisor (for any reason).
+ * On bare metal this function should return the same as local_clock.
+ * Architectures and sub-architectures can override this.
+ */
+notrace u64 __weak running_clock(void)
+{
+	return local_clock();
+}
diff --git a/kernel/sched/completion.c b/kernel/sched/completion.c
new file mode 100644
index 0000000000..3561ab533d
--- /dev/null
+++ b/kernel/sched/completion.c
@@ -0,0 +1,353 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Generic wait-for-completion handler;
+ *
+ * It differs from semaphores in that their default case is the opposite,
+ * wait_for_completion default blocks whereas semaphore default non-block. The
+ * interface also makes it easy to 'complete' multiple waiting threads,
+ * something which isn't entirely natural for semaphores.
+ *
+ * But more importantly, the primitive documents the usage. Semaphores would
+ * typically be used for exclusion which gives rise to priority inversion.
+ * Waiting for completion is a typically sync point, but not an exclusion point.
+ */
+
+static void complete_with_flags(struct completion *x, int wake_flags)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&x->wait.lock, flags);
+
+	if (x->done != UINT_MAX)
+		x->done++;
+	swake_up_locked(&x->wait, wake_flags);
+	raw_spin_unlock_irqrestore(&x->wait.lock, flags);
+}
+
+void complete_on_current_cpu(struct completion *x)
+{
+	return complete_with_flags(x, WF_CURRENT_CPU);
+}
+
+/**
+ * complete: - signals a single thread waiting on this completion
+ * @x:  holds the state of this particular completion
+ *
+ * This will wake up a single thread waiting on this completion. Threads will be
+ * awakened in the same order in which they were queued.
+ *
+ * See also complete_all(), wait_for_completion() and related routines.
+ *
+ * If this function wakes up a task, it executes a full memory barrier before
+ * accessing the task state.
+ */
+void complete(struct completion *x)
+{
+	complete_with_flags(x, 0);
+}
+EXPORT_SYMBOL(complete);
+
+/**
+ * complete_all: - signals all threads waiting on this completion
+ * @x:  holds the state of this particular completion
+ *
+ * This will wake up all threads waiting on this particular completion event.
+ *
+ * If this function wakes up a task, it executes a full memory barrier before
+ * accessing the task state.
+ *
+ * Since complete_all() sets the completion of @x permanently to done
+ * to allow multiple waiters to finish, a call to reinit_completion()
+ * must be used on @x if @x is to be used again. The code must make
+ * sure that all waiters have woken and finished before reinitializing
+ * @x. Also note that the function completion_done() can not be used
+ * to know if there are still waiters after complete_all() has been called.
+ */
+void complete_all(struct completion *x)
+{
+	unsigned long flags;
+
+	lockdep_assert_RT_in_threaded_ctx();
+
+	raw_spin_lock_irqsave(&x->wait.lock, flags);
+	x->done = UINT_MAX;
+	swake_up_all_locked(&x->wait);
+	raw_spin_unlock_irqrestore(&x->wait.lock, flags);
+}
+EXPORT_SYMBOL(complete_all);
+
+static inline long __sched
+do_wait_for_common(struct completion *x,
+		   long (*action)(long), long timeout, int state)
+{
+	if (!x->done) {
+		DECLARE_SWAITQUEUE(wait);
+
+		do {
+			if (signal_pending_state(state, current)) {
+				timeout = -ERESTARTSYS;
+				break;
+			}
+			__prepare_to_swait(&x->wait, &wait);
+			__set_current_state(state);
+			raw_spin_unlock_irq(&x->wait.lock);
+			timeout = action(timeout);
+			raw_spin_lock_irq(&x->wait.lock);
+		} while (!x->done && timeout);
+		__finish_swait(&x->wait, &wait);
+		if (!x->done)
+			return timeout;
+	}
+	if (x->done != UINT_MAX)
+		x->done--;
+	return timeout ?: 1;
+}
+
+static inline long __sched
+__wait_for_common(struct completion *x,
+		  long (*action)(long), long timeout, int state)
+{
+	might_sleep();
+
+	complete_acquire(x);
+
+	raw_spin_lock_irq(&x->wait.lock);
+	timeout = do_wait_for_common(x, action, timeout, state);
+	raw_spin_unlock_irq(&x->wait.lock);
+
+	complete_release(x);
+
+	return timeout;
+}
+
+static long __sched
+wait_for_common(struct completion *x, long timeout, int state)
+{
+	return __wait_for_common(x, schedule_timeout, timeout, state);
+}
+
+static long __sched
+wait_for_common_io(struct completion *x, long timeout, int state)
+{
+	return __wait_for_common(x, io_schedule_timeout, timeout, state);
+}
+
+/**
+ * wait_for_completion: - waits for completion of a task
+ * @x:  holds the state of this particular completion
+ *
+ * This waits to be signaled for completion of a specific task. It is NOT
+ * interruptible and there is no timeout.
+ *
+ * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
+ * and interrupt capability. Also see complete().
+ */
+void __sched wait_for_completion(struct completion *x)
+{
+	wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(wait_for_completion);
+
+/**
+ * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
+ * @x:  holds the state of this particular completion
+ * @timeout:  timeout value in jiffies
+ *
+ * This waits for either a completion of a specific task to be signaled or for a
+ * specified timeout to expire. The timeout is in jiffies. It is not
+ * interruptible.
+ *
+ * Return: 0 if timed out, and positive (at least 1, or number of jiffies left
+ * till timeout) if completed.
+ */
+unsigned long __sched
+wait_for_completion_timeout(struct completion *x, unsigned long timeout)
+{
+	return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(wait_for_completion_timeout);
+
+/**
+ * wait_for_completion_io: - waits for completion of a task
+ * @x:  holds the state of this particular completion
+ *
+ * This waits to be signaled for completion of a specific task. It is NOT
+ * interruptible and there is no timeout. The caller is accounted as waiting
+ * for IO (which traditionally means blkio only).
+ */
+void __sched wait_for_completion_io(struct completion *x)
+{
+	wait_for_common_io(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(wait_for_completion_io);
+
+/**
+ * wait_for_completion_io_timeout: - waits for completion of a task (w/timeout)
+ * @x:  holds the state of this particular completion
+ * @timeout:  timeout value in jiffies
+ *
+ * This waits for either a completion of a specific task to be signaled or for a
+ * specified timeout to expire. The timeout is in jiffies. It is not
+ * interruptible. The caller is accounted as waiting for IO (which traditionally
+ * means blkio only).
+ *
+ * Return: 0 if timed out, and positive (at least 1, or number of jiffies left
+ * till timeout) if completed.
+ */
+unsigned long __sched
+wait_for_completion_io_timeout(struct completion *x, unsigned long timeout)
+{
+	return wait_for_common_io(x, timeout, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(wait_for_completion_io_timeout);
+
+/**
+ * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
+ * @x:  holds the state of this particular completion
+ *
+ * This waits for completion of a specific task to be signaled. It is
+ * interruptible.
+ *
+ * Return: -ERESTARTSYS if interrupted, 0 if completed.
+ */
+int __sched wait_for_completion_interruptible(struct completion *x)
+{
+	long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
+
+	if (t == -ERESTARTSYS)
+		return t;
+	return 0;
+}
+EXPORT_SYMBOL(wait_for_completion_interruptible);
+
+/**
+ * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
+ * @x:  holds the state of this particular completion
+ * @timeout:  timeout value in jiffies
+ *
+ * This waits for either a completion of a specific task to be signaled or for a
+ * specified timeout to expire. It is interruptible. The timeout is in jiffies.
+ *
+ * Return: -ERESTARTSYS if interrupted, 0 if timed out, positive (at least 1,
+ * or number of jiffies left till timeout) if completed.
+ */
+long __sched
+wait_for_completion_interruptible_timeout(struct completion *x,
+					  unsigned long timeout)
+{
+	return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
+}
+EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
+
+/**
+ * wait_for_completion_killable: - waits for completion of a task (killable)
+ * @x:  holds the state of this particular completion
+ *
+ * This waits to be signaled for completion of a specific task. It can be
+ * interrupted by a kill signal.
+ *
+ * Return: -ERESTARTSYS if interrupted, 0 if completed.
+ */
+int __sched wait_for_completion_killable(struct completion *x)
+{
+	long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
+
+	if (t == -ERESTARTSYS)
+		return t;
+	return 0;
+}
+EXPORT_SYMBOL(wait_for_completion_killable);
+
+int __sched wait_for_completion_state(struct completion *x, unsigned int state)
+{
+	long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, state);
+
+	if (t == -ERESTARTSYS)
+		return t;
+	return 0;
+}
+EXPORT_SYMBOL(wait_for_completion_state);
+
+/**
+ * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
+ * @x:  holds the state of this particular completion
+ * @timeout:  timeout value in jiffies
+ *
+ * This waits for either a completion of a specific task to be
+ * signaled or for a specified timeout to expire. It can be
+ * interrupted by a kill signal. The timeout is in jiffies.
+ *
+ * Return: -ERESTARTSYS if interrupted, 0 if timed out, positive (at least 1,
+ * or number of jiffies left till timeout) if completed.
+ */
+long __sched
+wait_for_completion_killable_timeout(struct completion *x,
+				     unsigned long timeout)
+{
+	return wait_for_common(x, timeout, TASK_KILLABLE);
+}
+EXPORT_SYMBOL(wait_for_completion_killable_timeout);
+
+/**
+ *	try_wait_for_completion - try to decrement a completion without blocking
+ *	@x:	completion structure
+ *
+ *	Return: 0 if a decrement cannot be done without blocking
+ *		 1 if a decrement succeeded.
+ *
+ *	If a completion is being used as a counting completion,
+ *	attempt to decrement the counter without blocking. This
+ *	enables us to avoid waiting if the resource the completion
+ *	is protecting is not available.
+ */
+bool try_wait_for_completion(struct completion *x)
+{
+	unsigned long flags;
+	bool ret = true;
+
+	/*
+	 * Since x->done will need to be locked only
+	 * in the non-blocking case, we check x->done
+	 * first without taking the lock so we can
+	 * return early in the blocking case.
+	 */
+	if (!READ_ONCE(x->done))
+		return false;
+
+	raw_spin_lock_irqsave(&x->wait.lock, flags);
+	if (!x->done)
+		ret = false;
+	else if (x->done != UINT_MAX)
+		x->done--;
+	raw_spin_unlock_irqrestore(&x->wait.lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL(try_wait_for_completion);
+
+/**
+ *	completion_done - Test to see if a completion has any waiters
+ *	@x:	completion structure
+ *
+ *	Return: 0 if there are waiters (wait_for_completion() in progress)
+ *		 1 if there are no waiters.
+ *
+ *	Note, this will always return true if complete_all() was called on @X.
+ */
+bool completion_done(struct completion *x)
+{
+	unsigned long flags;
+
+	if (!READ_ONCE(x->done))
+		return false;
+
+	/*
+	 * If ->done, we need to wait for complete() to release ->wait.lock
+	 * otherwise we can end up freeing the completion before complete()
+	 * is done referencing it.
+	 */
+	raw_spin_lock_irqsave(&x->wait.lock, flags);
+	raw_spin_unlock_irqrestore(&x->wait.lock, flags);
+	return true;
+}
+EXPORT_SYMBOL(completion_done);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
new file mode 100644
index 0000000000..a854b71836
--- /dev/null
+++ b/kernel/sched/core.c
@@ -0,0 +1,12106 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  kernel/sched/core.c
+ *
+ *  Core kernel scheduler code and related syscalls
+ *
+ *  Copyright (C) 1991-2002  Linus Torvalds
+ */
+#include <linux/highmem.h>
+#include <linux/hrtimer_api.h>
+#include <linux/ktime_api.h>
+#include <linux/sched/signal.h>
+#include <linux/syscalls_api.h>
+#include <linux/debug_locks.h>
+#include <linux/prefetch.h>
+#include <linux/capability.h>
+#include <linux/pgtable_api.h>
+#include <linux/wait_bit.h>
+#include <linux/jiffies.h>
+#include <linux/spinlock_api.h>
+#include <linux/cpumask_api.h>
+#include <linux/lockdep_api.h>
+#include <linux/hardirq.h>
+#include <linux/softirq.h>
+#include <linux/refcount_api.h>
+#include <linux/topology.h>
+#include <linux/sched/clock.h>
+#include <linux/sched/cond_resched.h>
+#include <linux/sched/cputime.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/hotplug.h>
+#include <linux/sched/init.h>
+#include <linux/sched/isolation.h>
+#include <linux/sched/loadavg.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/nohz.h>
+#include <linux/sched/rseq_api.h>
+#include <linux/sched/rt.h>
+
+#include <linux/blkdev.h>
+#include <linux/context_tracking.h>
+#include <linux/cpuset.h>
+#include <linux/delayacct.h>
+#include <linux/init_task.h>
+#include <linux/interrupt.h>
+#include <linux/ioprio.h>
+#include <linux/kallsyms.h>
+#include <linux/kcov.h>
+#include <linux/kprobes.h>
+#include <linux/llist_api.h>
+#include <linux/mmu_context.h>
+#include <linux/mmzone.h>
+#include <linux/mutex_api.h>
+#include <linux/nmi.h>
+#include <linux/nospec.h>
+#include <linux/perf_event_api.h>
+#include <linux/profile.h>
+#include <linux/psi.h>
+#include <linux/rcuwait_api.h>
+#include <linux/sched/wake_q.h>
+#include <linux/scs.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+#include <linux/vtime.h>
+#include <linux/wait_api.h>
+#include <linux/workqueue_api.h>
+
+#ifdef CONFIG_PREEMPT_DYNAMIC
+# ifdef CONFIG_GENERIC_ENTRY
+#  include <linux/entry-common.h>
+# endif
+#endif
+
+#include <uapi/linux/sched/types.h>
+
+#include <asm/irq_regs.h>
+#include <asm/switch_to.h>
+#include <asm/tlb.h>
+
+#define CREATE_TRACE_POINTS
+#include <linux/sched/rseq_api.h>
+#include <trace/events/sched.h>
+#include <trace/events/ipi.h>
+#undef CREATE_TRACE_POINTS
+
+#include "sched.h"
+#include "stats.h"
+#include "autogroup.h"
+
+#include "autogroup.h"
+#include "pelt.h"
+#include "smp.h"
+#include "stats.h"
+
+#include "../workqueue_internal.h"
+#include "../../io_uring/io-wq.h"
+#include "../smpboot.h"
+
+EXPORT_TRACEPOINT_SYMBOL_GPL(ipi_send_cpu);
+EXPORT_TRACEPOINT_SYMBOL_GPL(ipi_send_cpumask);
+
+/*
+ * Export tracepoints that act as a bare tracehook (ie: have no trace event
+ * associated with them) to allow external modules to probe them.
+ */
+EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_cfs_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_rt_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_dl_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_irq_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_se_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_thermal_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(sched_cpu_capacity_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(sched_overutilized_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(sched_util_est_cfs_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(sched_util_est_se_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(sched_update_nr_running_tp);
+
+DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
+
+#ifdef CONFIG_SCHED_DEBUG
+/*
+ * Debugging: various feature bits
+ *
+ * If SCHED_DEBUG is disabled, each compilation unit has its own copy of
+ * sysctl_sched_features, defined in sched.h, to allow constants propagation
+ * at compile time and compiler optimization based on features default.
+ */
+#define SCHED_FEAT(name, enabled)	\
+	(1UL << __SCHED_FEAT_##name) * enabled |
+const_debug unsigned int sysctl_sched_features =
+#include "features.h"
+	0;
+#undef SCHED_FEAT
+
+/*
+ * Print a warning if need_resched is set for the given duration (if
+ * LATENCY_WARN is enabled).
+ *
+ * If sysctl_resched_latency_warn_once is set, only one warning will be shown
+ * per boot.
+ */
+__read_mostly int sysctl_resched_latency_warn_ms = 100;
+__read_mostly int sysctl_resched_latency_warn_once = 1;
+#endif /* CONFIG_SCHED_DEBUG */
+
+/*
+ * Number of tasks to iterate in a single balance run.
+ * Limited because this is done with IRQs disabled.
+ */
+const_debug unsigned int sysctl_sched_nr_migrate = SCHED_NR_MIGRATE_BREAK;
+
+__read_mostly int scheduler_running;
+
+#ifdef CONFIG_SCHED_CORE
+
+DEFINE_STATIC_KEY_FALSE(__sched_core_enabled);
+
+/* kernel prio, less is more */
+static inline int __task_prio(const struct task_struct *p)
+{
+	if (p->sched_class == &stop_sched_class) /* trumps deadline */
+		return -2;
+
+	if (rt_prio(p->prio)) /* includes deadline */
+		return p->prio; /* [-1, 99] */
+
+	if (p->sched_class == &idle_sched_class)
+		return MAX_RT_PRIO + NICE_WIDTH; /* 140 */
+
+	return MAX_RT_PRIO + MAX_NICE; /* 120, squash fair */
+}
+
+/*
+ * l(a,b)
+ * le(a,b) := !l(b,a)
+ * g(a,b)  := l(b,a)
+ * ge(a,b) := !l(a,b)
+ */
+
+/* real prio, less is less */
+static inline bool prio_less(const struct task_struct *a,
+			     const struct task_struct *b, bool in_fi)
+{
+
+	int pa = __task_prio(a), pb = __task_prio(b);
+
+	if (-pa < -pb)
+		return true;
+
+	if (-pb < -pa)
+		return false;
+
+	if (pa == -1) /* dl_prio() doesn't work because of stop_class above */
+		return !dl_time_before(a->dl.deadline, b->dl.deadline);
+
+	if (pa == MAX_RT_PRIO + MAX_NICE)	/* fair */
+		return cfs_prio_less(a, b, in_fi);
+
+	return false;
+}
+
+static inline bool __sched_core_less(const struct task_struct *a,
+				     const struct task_struct *b)
+{
+	if (a->core_cookie < b->core_cookie)
+		return true;
+
+	if (a->core_cookie > b->core_cookie)
+		return false;
+
+	/* flip prio, so high prio is leftmost */
+	if (prio_less(b, a, !!task_rq(a)->core->core_forceidle_count))
+		return true;
+
+	return false;
+}
+
+#define __node_2_sc(node) rb_entry((node), struct task_struct, core_node)
+
+static inline bool rb_sched_core_less(struct rb_node *a, const struct rb_node *b)
+{
+	return __sched_core_less(__node_2_sc(a), __node_2_sc(b));
+}
+
+static inline int rb_sched_core_cmp(const void *key, const struct rb_node *node)
+{
+	const struct task_struct *p = __node_2_sc(node);
+	unsigned long cookie = (unsigned long)key;
+
+	if (cookie < p->core_cookie)
+		return -1;
+
+	if (cookie > p->core_cookie)
+		return 1;
+
+	return 0;
+}
+
+void sched_core_enqueue(struct rq *rq, struct task_struct *p)
+{
+	rq->core->core_task_seq++;
+
+	if (!p->core_cookie)
+		return;
+
+	rb_add(&p->core_node, &rq->core_tree, rb_sched_core_less);
+}
+
+void sched_core_dequeue(struct rq *rq, struct task_struct *p, int flags)
+{
+	rq->core->core_task_seq++;
+
+	if (sched_core_enqueued(p)) {
+		rb_erase(&p->core_node, &rq->core_tree);
+		RB_CLEAR_NODE(&p->core_node);
+	}
+
+	/*
+	 * Migrating the last task off the cpu, with the cpu in forced idle
+	 * state. Reschedule to create an accounting edge for forced idle,
+	 * and re-examine whether the core is still in forced idle state.
+	 */
+	if (!(flags & DEQUEUE_SAVE) && rq->nr_running == 1 &&
+	    rq->core->core_forceidle_count && rq->curr == rq->idle)
+		resched_curr(rq);
+}
+
+static int sched_task_is_throttled(struct task_struct *p, int cpu)
+{
+	if (p->sched_class->task_is_throttled)
+		return p->sched_class->task_is_throttled(p, cpu);
+
+	return 0;
+}
+
+static struct task_struct *sched_core_next(struct task_struct *p, unsigned long cookie)
+{
+	struct rb_node *node = &p->core_node;
+	int cpu = task_cpu(p);
+
+	do {
+		node = rb_next(node);
+		if (!node)
+			return NULL;
+
+		p = __node_2_sc(node);
+		if (p->core_cookie != cookie)
+			return NULL;
+
+	} while (sched_task_is_throttled(p, cpu));
+
+	return p;
+}
+
+/*
+ * Find left-most (aka, highest priority) and unthrottled task matching @cookie.
+ * If no suitable task is found, NULL will be returned.
+ */
+static struct task_struct *sched_core_find(struct rq *rq, unsigned long cookie)
+{
+	struct task_struct *p;
+	struct rb_node *node;
+
+	node = rb_find_first((void *)cookie, &rq->core_tree, rb_sched_core_cmp);
+	if (!node)
+		return NULL;
+
+	p = __node_2_sc(node);
+	if (!sched_task_is_throttled(p, rq->cpu))
+		return p;
+
+	return sched_core_next(p, cookie);
+}
+
+/*
+ * Magic required such that:
+ *
+ *	raw_spin_rq_lock(rq);
+ *	...
+ *	raw_spin_rq_unlock(rq);
+ *
+ * ends up locking and unlocking the _same_ lock, and all CPUs
+ * always agree on what rq has what lock.
+ *
+ * XXX entirely possible to selectively enable cores, don't bother for now.
+ */
+
+static DEFINE_MUTEX(sched_core_mutex);
+static atomic_t sched_core_count;
+static struct cpumask sched_core_mask;
+
+static void sched_core_lock(int cpu, unsigned long *flags)
+{
+	const struct cpumask *smt_mask = cpu_smt_mask(cpu);
+	int t, i = 0;
+
+	local_irq_save(*flags);
+	for_each_cpu(t, smt_mask)
+		raw_spin_lock_nested(&cpu_rq(t)->__lock, i++);
+}
+
+static void sched_core_unlock(int cpu, unsigned long *flags)
+{
+	const struct cpumask *smt_mask = cpu_smt_mask(cpu);
+	int t;
+
+	for_each_cpu(t, smt_mask)
+		raw_spin_unlock(&cpu_rq(t)->__lock);
+	local_irq_restore(*flags);
+}
+
+static void __sched_core_flip(bool enabled)
+{
+	unsigned long flags;
+	int cpu, t;
+
+	cpus_read_lock();
+
+	/*
+	 * Toggle the online cores, one by one.
+	 */
+	cpumask_copy(&sched_core_mask, cpu_online_mask);
+	for_each_cpu(cpu, &sched_core_mask) {
+		const struct cpumask *smt_mask = cpu_smt_mask(cpu);
+
+		sched_core_lock(cpu, &flags);
+
+		for_each_cpu(t, smt_mask)
+			cpu_rq(t)->core_enabled = enabled;
+
+		cpu_rq(cpu)->core->core_forceidle_start = 0;
+
+		sched_core_unlock(cpu, &flags);
+
+		cpumask_andnot(&sched_core_mask, &sched_core_mask, smt_mask);
+	}
+
+	/*
+	 * Toggle the offline CPUs.
+	 */
+	for_each_cpu_andnot(cpu, cpu_possible_mask, cpu_online_mask)
+		cpu_rq(cpu)->core_enabled = enabled;
+
+	cpus_read_unlock();
+}
+
+static void sched_core_assert_empty(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		WARN_ON_ONCE(!RB_EMPTY_ROOT(&cpu_rq(cpu)->core_tree));
+}
+
+static void __sched_core_enable(void)
+{
+	static_branch_enable(&__sched_core_enabled);
+	/*
+	 * Ensure all previous instances of raw_spin_rq_*lock() have finished
+	 * and future ones will observe !sched_core_disabled().
+	 */
+	synchronize_rcu();
+	__sched_core_flip(true);
+	sched_core_assert_empty();
+}
+
+static void __sched_core_disable(void)
+{
+	sched_core_assert_empty();
+	__sched_core_flip(false);
+	static_branch_disable(&__sched_core_enabled);
+}
+
+void sched_core_get(void)
+{
+	if (atomic_inc_not_zero(&sched_core_count))
+		return;
+
+	mutex_lock(&sched_core_mutex);
+	if (!atomic_read(&sched_core_count))
+		__sched_core_enable();
+
+	smp_mb__before_atomic();
+	atomic_inc(&sched_core_count);
+	mutex_unlock(&sched_core_mutex);
+}
+
+static void __sched_core_put(struct work_struct *work)
+{
+	if (atomic_dec_and_mutex_lock(&sched_core_count, &sched_core_mutex)) {
+		__sched_core_disable();
+		mutex_unlock(&sched_core_mutex);
+	}
+}
+
+void sched_core_put(void)
+{
+	static DECLARE_WORK(_work, __sched_core_put);
+
+	/*
+	 * "There can be only one"
+	 *
+	 * Either this is the last one, or we don't actually need to do any
+	 * 'work'. If it is the last *again*, we rely on
+	 * WORK_STRUCT_PENDING_BIT.
+	 */
+	if (!atomic_add_unless(&sched_core_count, -1, 1))
+		schedule_work(&_work);
+}
+
+#else /* !CONFIG_SCHED_CORE */
+
+static inline void sched_core_enqueue(struct rq *rq, struct task_struct *p) { }
+static inline void
+sched_core_dequeue(struct rq *rq, struct task_struct *p, int flags) { }
+
+#endif /* CONFIG_SCHED_CORE */
+
+/*
+ * Serialization rules:
+ *
+ * Lock order:
+ *
+ *   p->pi_lock
+ *     rq->lock
+ *       hrtimer_cpu_base->lock (hrtimer_start() for bandwidth controls)
+ *
+ *  rq1->lock
+ *    rq2->lock  where: rq1 < rq2
+ *
+ * Regular state:
+ *
+ * Normal scheduling state is serialized by rq->lock. __schedule() takes the
+ * local CPU's rq->lock, it optionally removes the task from the runqueue and
+ * always looks at the local rq data structures to find the most eligible task
+ * to run next.
+ *
+ * Task enqueue is also under rq->lock, possibly taken from another CPU.
+ * Wakeups from another LLC domain might use an IPI to transfer the enqueue to
+ * the local CPU to avoid bouncing the runqueue state around [ see
+ * ttwu_queue_wakelist() ]
+ *
+ * Task wakeup, specifically wakeups that involve migration, are horribly
+ * complicated to avoid having to take two rq->locks.
+ *
+ * Special state:
+ *
+ * System-calls and anything external will use task_rq_lock() which acquires
+ * both p->pi_lock and rq->lock. As a consequence the state they change is
+ * stable while holding either lock:
+ *
+ *  - sched_setaffinity()/
+ *    set_cpus_allowed_ptr():	p->cpus_ptr, p->nr_cpus_allowed
+ *  - set_user_nice():		p->se.load, p->*prio
+ *  - __sched_setscheduler():	p->sched_class, p->policy, p->*prio,
+ *				p->se.load, p->rt_priority,
+ *				p->dl.dl_{runtime, deadline, period, flags, bw, density}
+ *  - sched_setnuma():		p->numa_preferred_nid
+ *  - sched_move_task():	p->sched_task_group
+ *  - uclamp_update_active()	p->uclamp*
+ *
+ * p->state <- TASK_*:
+ *
+ *   is changed locklessly using set_current_state(), __set_current_state() or
+ *   set_special_state(), see their respective comments, or by
+ *   try_to_wake_up(). This latter uses p->pi_lock to serialize against
+ *   concurrent self.
+ *
+ * p->on_rq <- { 0, 1 = TASK_ON_RQ_QUEUED, 2 = TASK_ON_RQ_MIGRATING }:
+ *
+ *   is set by activate_task() and cleared by deactivate_task(), under
+ *   rq->lock. Non-zero indicates the task is runnable, the special
+ *   ON_RQ_MIGRATING state is used for migration without holding both
+ *   rq->locks. It indicates task_cpu() is not stable, see task_rq_lock().
+ *
+ * p->on_cpu <- { 0, 1 }:
+ *
+ *   is set by prepare_task() and cleared by finish_task() such that it will be
+ *   set before p is scheduled-in and cleared after p is scheduled-out, both
+ *   under rq->lock. Non-zero indicates the task is running on its CPU.
+ *
+ *   [ The astute reader will observe that it is possible for two tasks on one
+ *     CPU to have ->on_cpu = 1 at the same time. ]
+ *
+ * task_cpu(p): is changed by set_task_cpu(), the rules are:
+ *
+ *  - Don't call set_task_cpu() on a blocked task:
+ *
+ *    We don't care what CPU we're not running on, this simplifies hotplug,
+ *    the CPU assignment of blocked tasks isn't required to be valid.
+ *
+ *  - for try_to_wake_up(), called under p->pi_lock:
+ *
+ *    This allows try_to_wake_up() to only take one rq->lock, see its comment.
+ *
+ *  - for migration called under rq->lock:
+ *    [ see task_on_rq_migrating() in task_rq_lock() ]
+ *
+ *    o move_queued_task()
+ *    o detach_task()
+ *
+ *  - for migration called under double_rq_lock():
+ *
+ *    o __migrate_swap_task()
+ *    o push_rt_task() / pull_rt_task()
+ *    o push_dl_task() / pull_dl_task()
+ *    o dl_task_offline_migration()
+ *
+ */
+
+void raw_spin_rq_lock_nested(struct rq *rq, int subclass)
+{
+	raw_spinlock_t *lock;
+
+	/* Matches synchronize_rcu() in __sched_core_enable() */
+	preempt_disable();
+	if (sched_core_disabled()) {
+		raw_spin_lock_nested(&rq->__lock, subclass);
+		/* preempt_count *MUST* be > 1 */
+		preempt_enable_no_resched();
+		return;
+	}
+
+	for (;;) {
+		lock = __rq_lockp(rq);
+		raw_spin_lock_nested(lock, subclass);
+		if (likely(lock == __rq_lockp(rq))) {
+			/* preempt_count *MUST* be > 1 */
+			preempt_enable_no_resched();
+			return;
+		}
+		raw_spin_unlock(lock);
+	}
+}
+
+bool raw_spin_rq_trylock(struct rq *rq)
+{
+	raw_spinlock_t *lock;
+	bool ret;
+
+	/* Matches synchronize_rcu() in __sched_core_enable() */
+	preempt_disable();
+	if (sched_core_disabled()) {
+		ret = raw_spin_trylock(&rq->__lock);
+		preempt_enable();
+		return ret;
+	}
+
+	for (;;) {
+		lock = __rq_lockp(rq);
+		ret = raw_spin_trylock(lock);
+		if (!ret || (likely(lock == __rq_lockp(rq)))) {
+			preempt_enable();
+			return ret;
+		}
+		raw_spin_unlock(lock);
+	}
+}
+
+void raw_spin_rq_unlock(struct rq *rq)
+{
+	raw_spin_unlock(rq_lockp(rq));
+}
+
+#ifdef CONFIG_SMP
+/*
+ * double_rq_lock - safely lock two runqueues
+ */
+void double_rq_lock(struct rq *rq1, struct rq *rq2)
+{
+	lockdep_assert_irqs_disabled();
+
+	if (rq_order_less(rq2, rq1))
+		swap(rq1, rq2);
+
+	raw_spin_rq_lock(rq1);
+	if (__rq_lockp(rq1) != __rq_lockp(rq2))
+		raw_spin_rq_lock_nested(rq2, SINGLE_DEPTH_NESTING);
+
+	double_rq_clock_clear_update(rq1, rq2);
+}
+#endif
+
+/*
+ * __task_rq_lock - lock the rq @p resides on.
+ */
+struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf)
+	__acquires(rq->lock)
+{
+	struct rq *rq;
+
+	lockdep_assert_held(&p->pi_lock);
+
+	for (;;) {
+		rq = task_rq(p);
+		raw_spin_rq_lock(rq);
+		if (likely(rq == task_rq(p) && !task_on_rq_migrating(p))) {
+			rq_pin_lock(rq, rf);
+			return rq;
+		}
+		raw_spin_rq_unlock(rq);
+
+		while (unlikely(task_on_rq_migrating(p)))
+			cpu_relax();
+	}
+}
+
+/*
+ * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
+ */
+struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf)
+	__acquires(p->pi_lock)
+	__acquires(rq->lock)
+{
+	struct rq *rq;
+
+	for (;;) {
+		raw_spin_lock_irqsave(&p->pi_lock, rf->flags);
+		rq = task_rq(p);
+		raw_spin_rq_lock(rq);
+		/*
+		 *	move_queued_task()		task_rq_lock()
+		 *
+		 *	ACQUIRE (rq->lock)
+		 *	[S] ->on_rq = MIGRATING		[L] rq = task_rq()
+		 *	WMB (__set_task_cpu())		ACQUIRE (rq->lock);
+		 *	[S] ->cpu = new_cpu		[L] task_rq()
+		 *					[L] ->on_rq
+		 *	RELEASE (rq->lock)
+		 *
+		 * If we observe the old CPU in task_rq_lock(), the acquire of
+		 * the old rq->lock will fully serialize against the stores.
+		 *
+		 * If we observe the new CPU in task_rq_lock(), the address
+		 * dependency headed by '[L] rq = task_rq()' and the acquire
+		 * will pair with the WMB to ensure we then also see migrating.
+		 */
+		if (likely(rq == task_rq(p) && !task_on_rq_migrating(p))) {
+			rq_pin_lock(rq, rf);
+			return rq;
+		}
+		raw_spin_rq_unlock(rq);
+		raw_spin_unlock_irqrestore(&p->pi_lock, rf->flags);
+
+		while (unlikely(task_on_rq_migrating(p)))
+			cpu_relax();
+	}
+}
+
+/*
+ * RQ-clock updating methods:
+ */
+
+static void update_rq_clock_task(struct rq *rq, s64 delta)
+{
+/*
+ * In theory, the compile should just see 0 here, and optimize out the call
+ * to sched_rt_avg_update. But I don't trust it...
+ */
+	s64 __maybe_unused steal = 0, irq_delta = 0;
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+	irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time;
+
+	/*
+	 * Since irq_time is only updated on {soft,}irq_exit, we might run into
+	 * this case when a previous update_rq_clock() happened inside a
+	 * {soft,}irq region.
+	 *
+	 * When this happens, we stop ->clock_task and only update the
+	 * prev_irq_time stamp to account for the part that fit, so that a next
+	 * update will consume the rest. This ensures ->clock_task is
+	 * monotonic.
+	 *
+	 * It does however cause some slight miss-attribution of {soft,}irq
+	 * time, a more accurate solution would be to update the irq_time using
+	 * the current rq->clock timestamp, except that would require using
+	 * atomic ops.
+	 */
+	if (irq_delta > delta)
+		irq_delta = delta;
+
+	rq->prev_irq_time += irq_delta;
+	delta -= irq_delta;
+	psi_account_irqtime(rq->curr, irq_delta);
+	delayacct_irq(rq->curr, irq_delta);
+#endif
+#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
+	if (static_key_false((&paravirt_steal_rq_enabled))) {
+		steal = paravirt_steal_clock(cpu_of(rq));
+		steal -= rq->prev_steal_time_rq;
+
+		if (unlikely(steal > delta))
+			steal = delta;
+
+		rq->prev_steal_time_rq += steal;
+		delta -= steal;
+	}
+#endif
+
+	rq->clock_task += delta;
+
+#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
+	if ((irq_delta + steal) && sched_feat(NONTASK_CAPACITY))
+		update_irq_load_avg(rq, irq_delta + steal);
+#endif
+	update_rq_clock_pelt(rq, delta);
+}
+
+void update_rq_clock(struct rq *rq)
+{
+	s64 delta;
+
+	lockdep_assert_rq_held(rq);
+
+	if (rq->clock_update_flags & RQCF_ACT_SKIP)
+		return;
+
+#ifdef CONFIG_SCHED_DEBUG
+	if (sched_feat(WARN_DOUBLE_CLOCK))
+		SCHED_WARN_ON(rq->clock_update_flags & RQCF_UPDATED);
+	rq->clock_update_flags |= RQCF_UPDATED;
+#endif
+
+	delta = sched_clock_cpu(cpu_of(rq)) - rq->clock;
+	if (delta < 0)
+		return;
+	rq->clock += delta;
+	update_rq_clock_task(rq, delta);
+}
+
+#ifdef CONFIG_SCHED_HRTICK
+/*
+ * Use HR-timers to deliver accurate preemption points.
+ */
+
+static void hrtick_clear(struct rq *rq)
+{
+	if (hrtimer_active(&rq->hrtick_timer))
+		hrtimer_cancel(&rq->hrtick_timer);
+}
+
+/*
+ * High-resolution timer tick.
+ * Runs from hardirq context with interrupts disabled.
+ */
+static enum hrtimer_restart hrtick(struct hrtimer *timer)
+{
+	struct rq *rq = container_of(timer, struct rq, hrtick_timer);
+	struct rq_flags rf;
+
+	WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
+
+	rq_lock(rq, &rf);
+	update_rq_clock(rq);
+	rq->curr->sched_class->task_tick(rq, rq->curr, 1);
+	rq_unlock(rq, &rf);
+
+	return HRTIMER_NORESTART;
+}
+
+#ifdef CONFIG_SMP
+
+static void __hrtick_restart(struct rq *rq)
+{
+	struct hrtimer *timer = &rq->hrtick_timer;
+	ktime_t time = rq->hrtick_time;
+
+	hrtimer_start(timer, time, HRTIMER_MODE_ABS_PINNED_HARD);
+}
+
+/*
+ * called from hardirq (IPI) context
+ */
+static void __hrtick_start(void *arg)
+{
+	struct rq *rq = arg;
+	struct rq_flags rf;
+
+	rq_lock(rq, &rf);
+	__hrtick_restart(rq);
+	rq_unlock(rq, &rf);
+}
+
+/*
+ * Called to set the hrtick timer state.
+ *
+ * called with rq->lock held and irqs disabled
+ */
+void hrtick_start(struct rq *rq, u64 delay)
+{
+	struct hrtimer *timer = &rq->hrtick_timer;
+	s64 delta;
+
+	/*
+	 * Don't schedule slices shorter than 10000ns, that just
+	 * doesn't make sense and can cause timer DoS.
+	 */
+	delta = max_t(s64, delay, 10000LL);
+	rq->hrtick_time = ktime_add_ns(timer->base->get_time(), delta);
+
+	if (rq == this_rq())
+		__hrtick_restart(rq);
+	else
+		smp_call_function_single_async(cpu_of(rq), &rq->hrtick_csd);
+}
+
+#else
+/*
+ * Called to set the hrtick timer state.
+ *
+ * called with rq->lock held and irqs disabled
+ */
+void hrtick_start(struct rq *rq, u64 delay)
+{
+	/*
+	 * Don't schedule slices shorter than 10000ns, that just
+	 * doesn't make sense. Rely on vruntime for fairness.
+	 */
+	delay = max_t(u64, delay, 10000LL);
+	hrtimer_start(&rq->hrtick_timer, ns_to_ktime(delay),
+		      HRTIMER_MODE_REL_PINNED_HARD);
+}
+
+#endif /* CONFIG_SMP */
+
+static void hrtick_rq_init(struct rq *rq)
+{
+#ifdef CONFIG_SMP
+	INIT_CSD(&rq->hrtick_csd, __hrtick_start, rq);
+#endif
+	hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
+	rq->hrtick_timer.function = hrtick;
+}
+#else	/* CONFIG_SCHED_HRTICK */
+static inline void hrtick_clear(struct rq *rq)
+{
+}
+
+static inline void hrtick_rq_init(struct rq *rq)
+{
+}
+#endif	/* CONFIG_SCHED_HRTICK */
+
+/*
+ * cmpxchg based fetch_or, macro so it works for different integer types
+ */
+#define fetch_or(ptr, mask)						\
+	({								\
+		typeof(ptr) _ptr = (ptr);				\
+		typeof(mask) _mask = (mask);				\
+		typeof(*_ptr) _val = *_ptr;				\
+									\
+		do {							\
+		} while (!try_cmpxchg(_ptr, &_val, _val | _mask));	\
+	_val;								\
+})
+
+#if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG)
+/*
+ * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG,
+ * this avoids any races wrt polling state changes and thereby avoids
+ * spurious IPIs.
+ */
+static inline bool set_nr_and_not_polling(struct task_struct *p)
+{
+	struct thread_info *ti = task_thread_info(p);
+	return !(fetch_or(&ti->flags, _TIF_NEED_RESCHED) & _TIF_POLLING_NRFLAG);
+}
+
+/*
+ * Atomically set TIF_NEED_RESCHED if TIF_POLLING_NRFLAG is set.
+ *
+ * If this returns true, then the idle task promises to call
+ * sched_ttwu_pending() and reschedule soon.
+ */
+static bool set_nr_if_polling(struct task_struct *p)
+{
+	struct thread_info *ti = task_thread_info(p);
+	typeof(ti->flags) val = READ_ONCE(ti->flags);
+
+	for (;;) {
+		if (!(val & _TIF_POLLING_NRFLAG))
+			return false;
+		if (val & _TIF_NEED_RESCHED)
+			return true;
+		if (try_cmpxchg(&ti->flags, &val, val | _TIF_NEED_RESCHED))
+			break;
+	}
+	return true;
+}
+
+#else
+static inline bool set_nr_and_not_polling(struct task_struct *p)
+{
+	set_tsk_need_resched(p);
+	return true;
+}
+
+#ifdef CONFIG_SMP
+static inline bool set_nr_if_polling(struct task_struct *p)
+{
+	return false;
+}
+#endif
+#endif
+
+static bool __wake_q_add(struct wake_q_head *head, struct task_struct *task)
+{
+	struct wake_q_node *node = &task->wake_q;
+
+	/*
+	 * Atomically grab the task, if ->wake_q is !nil already it means
+	 * it's already queued (either by us or someone else) and will get the
+	 * wakeup due to that.
+	 *
+	 * In order to ensure that a pending wakeup will observe our pending
+	 * state, even in the failed case, an explicit smp_mb() must be used.
+	 */
+	smp_mb__before_atomic();
+	if (unlikely(cmpxchg_relaxed(&node->next, NULL, WAKE_Q_TAIL)))
+		return false;
+
+	/*
+	 * The head is context local, there can be no concurrency.
+	 */
+	*head->lastp = node;
+	head->lastp = &node->next;
+	return true;
+}
+
+/**
+ * wake_q_add() - queue a wakeup for 'later' waking.
+ * @head: the wake_q_head to add @task to
+ * @task: the task to queue for 'later' wakeup
+ *
+ * Queue a task for later wakeup, most likely by the wake_up_q() call in the
+ * same context, _HOWEVER_ this is not guaranteed, the wakeup can come
+ * instantly.
+ *
+ * This function must be used as-if it were wake_up_process(); IOW the task
+ * must be ready to be woken at this location.
+ */
+void wake_q_add(struct wake_q_head *head, struct task_struct *task)
+{
+	if (__wake_q_add(head, task))
+		get_task_struct(task);
+}
+
+/**
+ * wake_q_add_safe() - safely queue a wakeup for 'later' waking.
+ * @head: the wake_q_head to add @task to
+ * @task: the task to queue for 'later' wakeup
+ *
+ * Queue a task for later wakeup, most likely by the wake_up_q() call in the
+ * same context, _HOWEVER_ this is not guaranteed, the wakeup can come
+ * instantly.
+ *
+ * This function must be used as-if it were wake_up_process(); IOW the task
+ * must be ready to be woken at this location.
+ *
+ * This function is essentially a task-safe equivalent to wake_q_add(). Callers
+ * that already hold reference to @task can call the 'safe' version and trust
+ * wake_q to do the right thing depending whether or not the @task is already
+ * queued for wakeup.
+ */
+void wake_q_add_safe(struct wake_q_head *head, struct task_struct *task)
+{
+	if (!__wake_q_add(head, task))
+		put_task_struct(task);
+}
+
+void wake_up_q(struct wake_q_head *head)
+{
+	struct wake_q_node *node = head->first;
+
+	while (node != WAKE_Q_TAIL) {
+		struct task_struct *task;
+
+		task = container_of(node, struct task_struct, wake_q);
+		/* Task can safely be re-inserted now: */
+		node = node->next;
+		task->wake_q.next = NULL;
+
+		/*
+		 * wake_up_process() executes a full barrier, which pairs with
+		 * the queueing in wake_q_add() so as not to miss wakeups.
+		 */
+		wake_up_process(task);
+		put_task_struct(task);
+	}
+}
+
+/*
+ * resched_curr - mark rq's current task 'to be rescheduled now'.
+ *
+ * On UP this means the setting of the need_resched flag, on SMP it
+ * might also involve a cross-CPU call to trigger the scheduler on
+ * the target CPU.
+ */
+void resched_curr(struct rq *rq)
+{
+	struct task_struct *curr = rq->curr;
+	int cpu;
+
+	lockdep_assert_rq_held(rq);
+
+	if (test_tsk_need_resched(curr))
+		return;
+
+	cpu = cpu_of(rq);
+
+	if (cpu == smp_processor_id()) {
+		set_tsk_need_resched(curr);
+		set_preempt_need_resched();
+		return;
+	}
+
+	if (set_nr_and_not_polling(curr))
+		smp_send_reschedule(cpu);
+	else
+		trace_sched_wake_idle_without_ipi(cpu);
+}
+
+void resched_cpu(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	unsigned long flags;
+
+	raw_spin_rq_lock_irqsave(rq, flags);
+	if (cpu_online(cpu) || cpu == smp_processor_id())
+		resched_curr(rq);
+	raw_spin_rq_unlock_irqrestore(rq, flags);
+}
+
+#ifdef CONFIG_SMP
+#ifdef CONFIG_NO_HZ_COMMON
+/*
+ * In the semi idle case, use the nearest busy CPU for migrating timers
+ * from an idle CPU.  This is good for power-savings.
+ *
+ * We don't do similar optimization for completely idle system, as
+ * selecting an idle CPU will add more delays to the timers than intended
+ * (as that CPU's timer base may not be uptodate wrt jiffies etc).
+ */
+int get_nohz_timer_target(void)
+{
+	int i, cpu = smp_processor_id(), default_cpu = -1;
+	struct sched_domain *sd;
+	const struct cpumask *hk_mask;
+
+	if (housekeeping_cpu(cpu, HK_TYPE_TIMER)) {
+		if (!idle_cpu(cpu))
+			return cpu;
+		default_cpu = cpu;
+	}
+
+	hk_mask = housekeeping_cpumask(HK_TYPE_TIMER);
+
+	guard(rcu)();
+
+	for_each_domain(cpu, sd) {
+		for_each_cpu_and(i, sched_domain_span(sd), hk_mask) {
+			if (cpu == i)
+				continue;
+
+			if (!idle_cpu(i))
+				return i;
+		}
+	}
+
+	if (default_cpu == -1)
+		default_cpu = housekeeping_any_cpu(HK_TYPE_TIMER);
+
+	return default_cpu;
+}
+
+/*
+ * When add_timer_on() enqueues a timer into the timer wheel of an
+ * idle CPU then this timer might expire before the next timer event
+ * which is scheduled to wake up that CPU. In case of a completely
+ * idle system the next event might even be infinite time into the
+ * future. wake_up_idle_cpu() ensures that the CPU is woken up and
+ * leaves the inner idle loop so the newly added timer is taken into
+ * account when the CPU goes back to idle and evaluates the timer
+ * wheel for the next timer event.
+ */
+static void wake_up_idle_cpu(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	if (cpu == smp_processor_id())
+		return;
+
+	if (set_nr_and_not_polling(rq->idle))
+		smp_send_reschedule(cpu);
+	else
+		trace_sched_wake_idle_without_ipi(cpu);
+}
+
+static bool wake_up_full_nohz_cpu(int cpu)
+{
+	/*
+	 * We just need the target to call irq_exit() and re-evaluate
+	 * the next tick. The nohz full kick at least implies that.
+	 * If needed we can still optimize that later with an
+	 * empty IRQ.
+	 */
+	if (cpu_is_offline(cpu))
+		return true;  /* Don't try to wake offline CPUs. */
+	if (tick_nohz_full_cpu(cpu)) {
+		if (cpu != smp_processor_id() ||
+		    tick_nohz_tick_stopped())
+			tick_nohz_full_kick_cpu(cpu);
+		return true;
+	}
+
+	return false;
+}
+
+/*
+ * Wake up the specified CPU.  If the CPU is going offline, it is the
+ * caller's responsibility to deal with the lost wakeup, for example,
+ * by hooking into the CPU_DEAD notifier like timers and hrtimers do.
+ */
+void wake_up_nohz_cpu(int cpu)
+{
+	if (!wake_up_full_nohz_cpu(cpu))
+		wake_up_idle_cpu(cpu);
+}
+
+static void nohz_csd_func(void *info)
+{
+	struct rq *rq = info;
+	int cpu = cpu_of(rq);
+	unsigned int flags;
+
+	/*
+	 * Release the rq::nohz_csd.
+	 */
+	flags = atomic_fetch_andnot(NOHZ_KICK_MASK | NOHZ_NEWILB_KICK, nohz_flags(cpu));
+	WARN_ON(!(flags & NOHZ_KICK_MASK));
+
+	rq->idle_balance = idle_cpu(cpu);
+	if (rq->idle_balance && !need_resched()) {
+		rq->nohz_idle_balance = flags;
+		raise_softirq_irqoff(SCHED_SOFTIRQ);
+	}
+}
+
+#endif /* CONFIG_NO_HZ_COMMON */
+
+#ifdef CONFIG_NO_HZ_FULL
+static inline bool __need_bw_check(struct rq *rq, struct task_struct *p)
+{
+	if (rq->nr_running != 1)
+		return false;
+
+	if (p->sched_class != &fair_sched_class)
+		return false;
+
+	if (!task_on_rq_queued(p))
+		return false;
+
+	return true;
+}
+
+bool sched_can_stop_tick(struct rq *rq)
+{
+	int fifo_nr_running;
+
+	/* Deadline tasks, even if single, need the tick */
+	if (rq->dl.dl_nr_running)
+		return false;
+
+	/*
+	 * If there are more than one RR tasks, we need the tick to affect the
+	 * actual RR behaviour.
+	 */
+	if (rq->rt.rr_nr_running) {
+		if (rq->rt.rr_nr_running == 1)
+			return true;
+		else
+			return false;
+	}
+
+	/*
+	 * If there's no RR tasks, but FIFO tasks, we can skip the tick, no
+	 * forced preemption between FIFO tasks.
+	 */
+	fifo_nr_running = rq->rt.rt_nr_running - rq->rt.rr_nr_running;
+	if (fifo_nr_running)
+		return true;
+
+	/*
+	 * If there are no DL,RR/FIFO tasks, there must only be CFS tasks left;
+	 * if there's more than one we need the tick for involuntary
+	 * preemption.
+	 */
+	if (rq->nr_running > 1)
+		return false;
+
+	/*
+	 * If there is one task and it has CFS runtime bandwidth constraints
+	 * and it's on the cpu now we don't want to stop the tick.
+	 * This check prevents clearing the bit if a newly enqueued task here is
+	 * dequeued by migrating while the constrained task continues to run.
+	 * E.g. going from 2->1 without going through pick_next_task().
+	 */
+	if (sched_feat(HZ_BW) && __need_bw_check(rq, rq->curr)) {
+		if (cfs_task_bw_constrained(rq->curr))
+			return false;
+	}
+
+	return true;
+}
+#endif /* CONFIG_NO_HZ_FULL */
+#endif /* CONFIG_SMP */
+
+#if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
+			(defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
+/*
+ * Iterate task_group tree rooted at *from, calling @down when first entering a
+ * node and @up when leaving it for the final time.
+ *
+ * Caller must hold rcu_lock or sufficient equivalent.
+ */
+int walk_tg_tree_from(struct task_group *from,
+			     tg_visitor down, tg_visitor up, void *data)
+{
+	struct task_group *parent, *child;
+	int ret;
+
+	parent = from;
+
+down:
+	ret = (*down)(parent, data);
+	if (ret)
+		goto out;
+	list_for_each_entry_rcu(child, &parent->children, siblings) {
+		parent = child;
+		goto down;
+
+up:
+		continue;
+	}
+	ret = (*up)(parent, data);
+	if (ret || parent == from)
+		goto out;
+
+	child = parent;
+	parent = parent->parent;
+	if (parent)
+		goto up;
+out:
+	return ret;
+}
+
+int tg_nop(struct task_group *tg, void *data)
+{
+	return 0;
+}
+#endif
+
+static void set_load_weight(struct task_struct *p, bool update_load)
+{
+	int prio = p->static_prio - MAX_RT_PRIO;
+	struct load_weight *load = &p->se.load;
+
+	/*
+	 * SCHED_IDLE tasks get minimal weight:
+	 */
+	if (task_has_idle_policy(p)) {
+		load->weight = scale_load(WEIGHT_IDLEPRIO);
+		load->inv_weight = WMULT_IDLEPRIO;
+		return;
+	}
+
+	/*
+	 * SCHED_OTHER tasks have to update their load when changing their
+	 * weight
+	 */
+	if (update_load && p->sched_class == &fair_sched_class) {
+		reweight_task(p, prio);
+	} else {
+		load->weight = scale_load(sched_prio_to_weight[prio]);
+		load->inv_weight = sched_prio_to_wmult[prio];
+	}
+}
+
+#ifdef CONFIG_UCLAMP_TASK
+/*
+ * Serializes updates of utilization clamp values
+ *
+ * The (slow-path) user-space triggers utilization clamp value updates which
+ * can require updates on (fast-path) scheduler's data structures used to
+ * support enqueue/dequeue operations.
+ * While the per-CPU rq lock protects fast-path update operations, user-space
+ * requests are serialized using a mutex to reduce the risk of conflicting
+ * updates or API abuses.
+ */
+static DEFINE_MUTEX(uclamp_mutex);
+
+/* Max allowed minimum utilization */
+static unsigned int __maybe_unused sysctl_sched_uclamp_util_min = SCHED_CAPACITY_SCALE;
+
+/* Max allowed maximum utilization */
+static unsigned int __maybe_unused sysctl_sched_uclamp_util_max = SCHED_CAPACITY_SCALE;
+
+/*
+ * By default RT tasks run at the maximum performance point/capacity of the
+ * system. Uclamp enforces this by always setting UCLAMP_MIN of RT tasks to
+ * SCHED_CAPACITY_SCALE.
+ *
+ * This knob allows admins to change the default behavior when uclamp is being
+ * used. In battery powered devices, particularly, running at the maximum
+ * capacity and frequency will increase energy consumption and shorten the
+ * battery life.
+ *
+ * This knob only affects RT tasks that their uclamp_se->user_defined == false.
+ *
+ * This knob will not override the system default sched_util_clamp_min defined
+ * above.
+ */
+static unsigned int sysctl_sched_uclamp_util_min_rt_default = SCHED_CAPACITY_SCALE;
+
+/* All clamps are required to be less or equal than these values */
+static struct uclamp_se uclamp_default[UCLAMP_CNT];
+
+/*
+ * This static key is used to reduce the uclamp overhead in the fast path. It
+ * primarily disables the call to uclamp_rq_{inc, dec}() in
+ * enqueue/dequeue_task().
+ *
+ * This allows users to continue to enable uclamp in their kernel config with
+ * minimum uclamp overhead in the fast path.
+ *
+ * As soon as userspace modifies any of the uclamp knobs, the static key is
+ * enabled, since we have an actual users that make use of uclamp
+ * functionality.
+ *
+ * The knobs that would enable this static key are:
+ *
+ *   * A task modifying its uclamp value with sched_setattr().
+ *   * An admin modifying the sysctl_sched_uclamp_{min, max} via procfs.
+ *   * An admin modifying the cgroup cpu.uclamp.{min, max}
+ */
+DEFINE_STATIC_KEY_FALSE(sched_uclamp_used);
+
+/* Integer rounded range for each bucket */
+#define UCLAMP_BUCKET_DELTA DIV_ROUND_CLOSEST(SCHED_CAPACITY_SCALE, UCLAMP_BUCKETS)
+
+#define for_each_clamp_id(clamp_id) \
+	for ((clamp_id) = 0; (clamp_id) < UCLAMP_CNT; (clamp_id)++)
+
+static inline unsigned int uclamp_bucket_id(unsigned int clamp_value)
+{
+	return min_t(unsigned int, clamp_value / UCLAMP_BUCKET_DELTA, UCLAMP_BUCKETS - 1);
+}
+
+static inline unsigned int uclamp_none(enum uclamp_id clamp_id)
+{
+	if (clamp_id == UCLAMP_MIN)
+		return 0;
+	return SCHED_CAPACITY_SCALE;
+}
+
+static inline void uclamp_se_set(struct uclamp_se *uc_se,
+				 unsigned int value, bool user_defined)
+{
+	uc_se->value = value;
+	uc_se->bucket_id = uclamp_bucket_id(value);
+	uc_se->user_defined = user_defined;
+}
+
+static inline unsigned int
+uclamp_idle_value(struct rq *rq, enum uclamp_id clamp_id,
+		  unsigned int clamp_value)
+{
+	/*
+	 * Avoid blocked utilization pushing up the frequency when we go
+	 * idle (which drops the max-clamp) by retaining the last known
+	 * max-clamp.
+	 */
+	if (clamp_id == UCLAMP_MAX) {
+		rq->uclamp_flags |= UCLAMP_FLAG_IDLE;
+		return clamp_value;
+	}
+
+	return uclamp_none(UCLAMP_MIN);
+}
+
+static inline void uclamp_idle_reset(struct rq *rq, enum uclamp_id clamp_id,
+				     unsigned int clamp_value)
+{
+	/* Reset max-clamp retention only on idle exit */
+	if (!(rq->uclamp_flags & UCLAMP_FLAG_IDLE))
+		return;
+
+	uclamp_rq_set(rq, clamp_id, clamp_value);
+}
+
+static inline
+unsigned int uclamp_rq_max_value(struct rq *rq, enum uclamp_id clamp_id,
+				   unsigned int clamp_value)
+{
+	struct uclamp_bucket *bucket = rq->uclamp[clamp_id].bucket;
+	int bucket_id = UCLAMP_BUCKETS - 1;
+
+	/*
+	 * Since both min and max clamps are max aggregated, find the
+	 * top most bucket with tasks in.
+	 */
+	for ( ; bucket_id >= 0; bucket_id--) {
+		if (!bucket[bucket_id].tasks)
+			continue;
+		return bucket[bucket_id].value;
+	}
+
+	/* No tasks -- default clamp values */
+	return uclamp_idle_value(rq, clamp_id, clamp_value);
+}
+
+static void __uclamp_update_util_min_rt_default(struct task_struct *p)
+{
+	unsigned int default_util_min;
+	struct uclamp_se *uc_se;
+
+	lockdep_assert_held(&p->pi_lock);
+
+	uc_se = &p->uclamp_req[UCLAMP_MIN];
+
+	/* Only sync if user didn't override the default */
+	if (uc_se->user_defined)
+		return;
+
+	default_util_min = sysctl_sched_uclamp_util_min_rt_default;
+	uclamp_se_set(uc_se, default_util_min, false);
+}
+
+static void uclamp_update_util_min_rt_default(struct task_struct *p)
+{
+	struct rq_flags rf;
+	struct rq *rq;
+
+	if (!rt_task(p))
+		return;
+
+	/* Protect updates to p->uclamp_* */
+	rq = task_rq_lock(p, &rf);
+	__uclamp_update_util_min_rt_default(p);
+	task_rq_unlock(rq, p, &rf);
+}
+
+static inline struct uclamp_se
+uclamp_tg_restrict(struct task_struct *p, enum uclamp_id clamp_id)
+{
+	/* Copy by value as we could modify it */
+	struct uclamp_se uc_req = p->uclamp_req[clamp_id];
+#ifdef CONFIG_UCLAMP_TASK_GROUP
+	unsigned int tg_min, tg_max, value;
+
+	/*
+	 * Tasks in autogroups or root task group will be
+	 * restricted by system defaults.
+	 */
+	if (task_group_is_autogroup(task_group(p)))
+		return uc_req;
+	if (task_group(p) == &root_task_group)
+		return uc_req;
+
+	tg_min = task_group(p)->uclamp[UCLAMP_MIN].value;
+	tg_max = task_group(p)->uclamp[UCLAMP_MAX].value;
+	value = uc_req.value;
+	value = clamp(value, tg_min, tg_max);
+	uclamp_se_set(&uc_req, value, false);
+#endif
+
+	return uc_req;
+}
+
+/*
+ * The effective clamp bucket index of a task depends on, by increasing
+ * priority:
+ * - the task specific clamp value, when explicitly requested from userspace
+ * - the task group effective clamp value, for tasks not either in the root
+ *   group or in an autogroup
+ * - the system default clamp value, defined by the sysadmin
+ */
+static inline struct uclamp_se
+uclamp_eff_get(struct task_struct *p, enum uclamp_id clamp_id)
+{
+	struct uclamp_se uc_req = uclamp_tg_restrict(p, clamp_id);
+	struct uclamp_se uc_max = uclamp_default[clamp_id];
+
+	/* System default restrictions always apply */
+	if (unlikely(uc_req.value > uc_max.value))
+		return uc_max;
+
+	return uc_req;
+}
+
+unsigned long uclamp_eff_value(struct task_struct *p, enum uclamp_id clamp_id)
+{
+	struct uclamp_se uc_eff;
+
+	/* Task currently refcounted: use back-annotated (effective) value */
+	if (p->uclamp[clamp_id].active)
+		return (unsigned long)p->uclamp[clamp_id].value;
+
+	uc_eff = uclamp_eff_get(p, clamp_id);
+
+	return (unsigned long)uc_eff.value;
+}
+
+/*
+ * When a task is enqueued on a rq, the clamp bucket currently defined by the
+ * task's uclamp::bucket_id is refcounted on that rq. This also immediately
+ * updates the rq's clamp value if required.
+ *
+ * Tasks can have a task-specific value requested from user-space, track
+ * within each bucket the maximum value for tasks refcounted in it.
+ * This "local max aggregation" allows to track the exact "requested" value
+ * for each bucket when all its RUNNABLE tasks require the same clamp.
+ */
+static inline void uclamp_rq_inc_id(struct rq *rq, struct task_struct *p,
+				    enum uclamp_id clamp_id)
+{
+	struct uclamp_rq *uc_rq = &rq->uclamp[clamp_id];
+	struct uclamp_se *uc_se = &p->uclamp[clamp_id];
+	struct uclamp_bucket *bucket;
+
+	lockdep_assert_rq_held(rq);
+
+	/* Update task effective clamp */
+	p->uclamp[clamp_id] = uclamp_eff_get(p, clamp_id);
+
+	bucket = &uc_rq->bucket[uc_se->bucket_id];
+	bucket->tasks++;
+	uc_se->active = true;
+
+	uclamp_idle_reset(rq, clamp_id, uc_se->value);
+
+	/*
+	 * Local max aggregation: rq buckets always track the max
+	 * "requested" clamp value of its RUNNABLE tasks.
+	 */
+	if (bucket->tasks == 1 || uc_se->value > bucket->value)
+		bucket->value = uc_se->value;
+
+	if (uc_se->value > uclamp_rq_get(rq, clamp_id))
+		uclamp_rq_set(rq, clamp_id, uc_se->value);
+}
+
+/*
+ * When a task is dequeued from a rq, the clamp bucket refcounted by the task
+ * is released. If this is the last task reference counting the rq's max
+ * active clamp value, then the rq's clamp value is updated.
+ *
+ * Both refcounted tasks and rq's cached clamp values are expected to be
+ * always valid. If it's detected they are not, as defensive programming,
+ * enforce the expected state and warn.
+ */
+static inline void uclamp_rq_dec_id(struct rq *rq, struct task_struct *p,
+				    enum uclamp_id clamp_id)
+{
+	struct uclamp_rq *uc_rq = &rq->uclamp[clamp_id];
+	struct uclamp_se *uc_se = &p->uclamp[clamp_id];
+	struct uclamp_bucket *bucket;
+	unsigned int bkt_clamp;
+	unsigned int rq_clamp;
+
+	lockdep_assert_rq_held(rq);
+
+	/*
+	 * If sched_uclamp_used was enabled after task @p was enqueued,
+	 * we could end up with unbalanced call to uclamp_rq_dec_id().
+	 *
+	 * In this case the uc_se->active flag should be false since no uclamp
+	 * accounting was performed at enqueue time and we can just return
+	 * here.
+	 *
+	 * Need to be careful of the following enqueue/dequeue ordering
+	 * problem too
+	 *
+	 *	enqueue(taskA)
+	 *	// sched_uclamp_used gets enabled
+	 *	enqueue(taskB)
+	 *	dequeue(taskA)
+	 *	// Must not decrement bucket->tasks here
+	 *	dequeue(taskB)
+	 *
+	 * where we could end up with stale data in uc_se and
+	 * bucket[uc_se->bucket_id].
+	 *
+	 * The following check here eliminates the possibility of such race.
+	 */
+	if (unlikely(!uc_se->active))
+		return;
+
+	bucket = &uc_rq->bucket[uc_se->bucket_id];
+
+	SCHED_WARN_ON(!bucket->tasks);
+	if (likely(bucket->tasks))
+		bucket->tasks--;
+
+	uc_se->active = false;
+
+	/*
+	 * Keep "local max aggregation" simple and accept to (possibly)
+	 * overboost some RUNNABLE tasks in the same bucket.
+	 * The rq clamp bucket value is reset to its base value whenever
+	 * there are no more RUNNABLE tasks refcounting it.
+	 */
+	if (likely(bucket->tasks))
+		return;
+
+	rq_clamp = uclamp_rq_get(rq, clamp_id);
+	/*
+	 * Defensive programming: this should never happen. If it happens,
+	 * e.g. due to future modification, warn and fixup the expected value.
+	 */
+	SCHED_WARN_ON(bucket->value > rq_clamp);
+	if (bucket->value >= rq_clamp) {
+		bkt_clamp = uclamp_rq_max_value(rq, clamp_id, uc_se->value);
+		uclamp_rq_set(rq, clamp_id, bkt_clamp);
+	}
+}
+
+static inline void uclamp_rq_inc(struct rq *rq, struct task_struct *p)
+{
+	enum uclamp_id clamp_id;
+
+	/*
+	 * Avoid any overhead until uclamp is actually used by the userspace.
+	 *
+	 * The condition is constructed such that a NOP is generated when
+	 * sched_uclamp_used is disabled.
+	 */
+	if (!static_branch_unlikely(&sched_uclamp_used))
+		return;
+
+	if (unlikely(!p->sched_class->uclamp_enabled))
+		return;
+
+	for_each_clamp_id(clamp_id)
+		uclamp_rq_inc_id(rq, p, clamp_id);
+
+	/* Reset clamp idle holding when there is one RUNNABLE task */
+	if (rq->uclamp_flags & UCLAMP_FLAG_IDLE)
+		rq->uclamp_flags &= ~UCLAMP_FLAG_IDLE;
+}
+
+static inline void uclamp_rq_dec(struct rq *rq, struct task_struct *p)
+{
+	enum uclamp_id clamp_id;
+
+	/*
+	 * Avoid any overhead until uclamp is actually used by the userspace.
+	 *
+	 * The condition is constructed such that a NOP is generated when
+	 * sched_uclamp_used is disabled.
+	 */
+	if (!static_branch_unlikely(&sched_uclamp_used))
+		return;
+
+	if (unlikely(!p->sched_class->uclamp_enabled))
+		return;
+
+	for_each_clamp_id(clamp_id)
+		uclamp_rq_dec_id(rq, p, clamp_id);
+}
+
+static inline void uclamp_rq_reinc_id(struct rq *rq, struct task_struct *p,
+				      enum uclamp_id clamp_id)
+{
+	if (!p->uclamp[clamp_id].active)
+		return;
+
+	uclamp_rq_dec_id(rq, p, clamp_id);
+	uclamp_rq_inc_id(rq, p, clamp_id);
+
+	/*
+	 * Make sure to clear the idle flag if we've transiently reached 0
+	 * active tasks on rq.
+	 */
+	if (clamp_id == UCLAMP_MAX && (rq->uclamp_flags & UCLAMP_FLAG_IDLE))
+		rq->uclamp_flags &= ~UCLAMP_FLAG_IDLE;
+}
+
+static inline void
+uclamp_update_active(struct task_struct *p)
+{
+	enum uclamp_id clamp_id;
+	struct rq_flags rf;
+	struct rq *rq;
+
+	/*
+	 * Lock the task and the rq where the task is (or was) queued.
+	 *
+	 * We might lock the (previous) rq of a !RUNNABLE task, but that's the
+	 * price to pay to safely serialize util_{min,max} updates with
+	 * enqueues, dequeues and migration operations.
+	 * This is the same locking schema used by __set_cpus_allowed_ptr().
+	 */
+	rq = task_rq_lock(p, &rf);
+
+	/*
+	 * Setting the clamp bucket is serialized by task_rq_lock().
+	 * If the task is not yet RUNNABLE and its task_struct is not
+	 * affecting a valid clamp bucket, the next time it's enqueued,
+	 * it will already see the updated clamp bucket value.
+	 */
+	for_each_clamp_id(clamp_id)
+		uclamp_rq_reinc_id(rq, p, clamp_id);
+
+	task_rq_unlock(rq, p, &rf);
+}
+
+#ifdef CONFIG_UCLAMP_TASK_GROUP
+static inline void
+uclamp_update_active_tasks(struct cgroup_subsys_state *css)
+{
+	struct css_task_iter it;
+	struct task_struct *p;
+
+	css_task_iter_start(css, 0, &it);
+	while ((p = css_task_iter_next(&it)))
+		uclamp_update_active(p);
+	css_task_iter_end(&it);
+}
+
+static void cpu_util_update_eff(struct cgroup_subsys_state *css);
+#endif
+
+#ifdef CONFIG_SYSCTL
+#ifdef CONFIG_UCLAMP_TASK
+#ifdef CONFIG_UCLAMP_TASK_GROUP
+static void uclamp_update_root_tg(void)
+{
+	struct task_group *tg = &root_task_group;
+
+	uclamp_se_set(&tg->uclamp_req[UCLAMP_MIN],
+		      sysctl_sched_uclamp_util_min, false);
+	uclamp_se_set(&tg->uclamp_req[UCLAMP_MAX],
+		      sysctl_sched_uclamp_util_max, false);
+
+	rcu_read_lock();
+	cpu_util_update_eff(&root_task_group.css);
+	rcu_read_unlock();
+}
+#else
+static void uclamp_update_root_tg(void) { }
+#endif
+
+static void uclamp_sync_util_min_rt_default(void)
+{
+	struct task_struct *g, *p;
+
+	/*
+	 * copy_process()			sysctl_uclamp
+	 *					  uclamp_min_rt = X;
+	 *   write_lock(&tasklist_lock)		  read_lock(&tasklist_lock)
+	 *   // link thread			  smp_mb__after_spinlock()
+	 *   write_unlock(&tasklist_lock)	  read_unlock(&tasklist_lock);
+	 *   sched_post_fork()			  for_each_process_thread()
+	 *     __uclamp_sync_rt()		    __uclamp_sync_rt()
+	 *
+	 * Ensures that either sched_post_fork() will observe the new
+	 * uclamp_min_rt or for_each_process_thread() will observe the new
+	 * task.
+	 */
+	read_lock(&tasklist_lock);
+	smp_mb__after_spinlock();
+	read_unlock(&tasklist_lock);
+
+	rcu_read_lock();
+	for_each_process_thread(g, p)
+		uclamp_update_util_min_rt_default(p);
+	rcu_read_unlock();
+}
+
+static int sysctl_sched_uclamp_handler(struct ctl_table *table, int write,
+				void *buffer, size_t *lenp, loff_t *ppos)
+{
+	bool update_root_tg = false;
+	int old_min, old_max, old_min_rt;
+	int result;
+
+	guard(mutex)(&uclamp_mutex);
+
+	old_min = sysctl_sched_uclamp_util_min;
+	old_max = sysctl_sched_uclamp_util_max;
+	old_min_rt = sysctl_sched_uclamp_util_min_rt_default;
+
+	result = proc_dointvec(table, write, buffer, lenp, ppos);
+	if (result)
+		goto undo;
+	if (!write)
+		return 0;
+
+	if (sysctl_sched_uclamp_util_min > sysctl_sched_uclamp_util_max ||
+	    sysctl_sched_uclamp_util_max > SCHED_CAPACITY_SCALE	||
+	    sysctl_sched_uclamp_util_min_rt_default > SCHED_CAPACITY_SCALE) {
+
+		result = -EINVAL;
+		goto undo;
+	}
+
+	if (old_min != sysctl_sched_uclamp_util_min) {
+		uclamp_se_set(&uclamp_default[UCLAMP_MIN],
+			      sysctl_sched_uclamp_util_min, false);
+		update_root_tg = true;
+	}
+	if (old_max != sysctl_sched_uclamp_util_max) {
+		uclamp_se_set(&uclamp_default[UCLAMP_MAX],
+			      sysctl_sched_uclamp_util_max, false);
+		update_root_tg = true;
+	}
+
+	if (update_root_tg) {
+		static_branch_enable(&sched_uclamp_used);
+		uclamp_update_root_tg();
+	}
+
+	if (old_min_rt != sysctl_sched_uclamp_util_min_rt_default) {
+		static_branch_enable(&sched_uclamp_used);
+		uclamp_sync_util_min_rt_default();
+	}
+
+	/*
+	 * We update all RUNNABLE tasks only when task groups are in use.
+	 * Otherwise, keep it simple and do just a lazy update at each next
+	 * task enqueue time.
+	 */
+	return 0;
+
+undo:
+	sysctl_sched_uclamp_util_min = old_min;
+	sysctl_sched_uclamp_util_max = old_max;
+	sysctl_sched_uclamp_util_min_rt_default = old_min_rt;
+	return result;
+}
+#endif
+#endif
+
+static int uclamp_validate(struct task_struct *p,
+			   const struct sched_attr *attr)
+{
+	int util_min = p->uclamp_req[UCLAMP_MIN].value;
+	int util_max = p->uclamp_req[UCLAMP_MAX].value;
+
+	if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MIN) {
+		util_min = attr->sched_util_min;
+
+		if (util_min + 1 > SCHED_CAPACITY_SCALE + 1)
+			return -EINVAL;
+	}
+
+	if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MAX) {
+		util_max = attr->sched_util_max;
+
+		if (util_max + 1 > SCHED_CAPACITY_SCALE + 1)
+			return -EINVAL;
+	}
+
+	if (util_min != -1 && util_max != -1 && util_min > util_max)
+		return -EINVAL;
+
+	/*
+	 * We have valid uclamp attributes; make sure uclamp is enabled.
+	 *
+	 * We need to do that here, because enabling static branches is a
+	 * blocking operation which obviously cannot be done while holding
+	 * scheduler locks.
+	 */
+	static_branch_enable(&sched_uclamp_used);
+
+	return 0;
+}
+
+static bool uclamp_reset(const struct sched_attr *attr,
+			 enum uclamp_id clamp_id,
+			 struct uclamp_se *uc_se)
+{
+	/* Reset on sched class change for a non user-defined clamp value. */
+	if (likely(!(attr->sched_flags & SCHED_FLAG_UTIL_CLAMP)) &&
+	    !uc_se->user_defined)
+		return true;
+
+	/* Reset on sched_util_{min,max} == -1. */
+	if (clamp_id == UCLAMP_MIN &&
+	    attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MIN &&
+	    attr->sched_util_min == -1) {
+		return true;
+	}
+
+	if (clamp_id == UCLAMP_MAX &&
+	    attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MAX &&
+	    attr->sched_util_max == -1) {
+		return true;
+	}
+
+	return false;
+}
+
+static void __setscheduler_uclamp(struct task_struct *p,
+				  const struct sched_attr *attr)
+{
+	enum uclamp_id clamp_id;
+
+	for_each_clamp_id(clamp_id) {
+		struct uclamp_se *uc_se = &p->uclamp_req[clamp_id];
+		unsigned int value;
+
+		if (!uclamp_reset(attr, clamp_id, uc_se))
+			continue;
+
+		/*
+		 * RT by default have a 100% boost value that could be modified
+		 * at runtime.
+		 */
+		if (unlikely(rt_task(p) && clamp_id == UCLAMP_MIN))
+			value = sysctl_sched_uclamp_util_min_rt_default;
+		else
+			value = uclamp_none(clamp_id);
+
+		uclamp_se_set(uc_se, value, false);
+
+	}
+
+	if (likely(!(attr->sched_flags & SCHED_FLAG_UTIL_CLAMP)))
+		return;
+
+	if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MIN &&
+	    attr->sched_util_min != -1) {
+		uclamp_se_set(&p->uclamp_req[UCLAMP_MIN],
+			      attr->sched_util_min, true);
+	}
+
+	if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MAX &&
+	    attr->sched_util_max != -1) {
+		uclamp_se_set(&p->uclamp_req[UCLAMP_MAX],
+			      attr->sched_util_max, true);
+	}
+}
+
+static void uclamp_fork(struct task_struct *p)
+{
+	enum uclamp_id clamp_id;
+
+	/*
+	 * We don't need to hold task_rq_lock() when updating p->uclamp_* here
+	 * as the task is still at its early fork stages.
+	 */
+	for_each_clamp_id(clamp_id)
+		p->uclamp[clamp_id].active = false;
+
+	if (likely(!p->sched_reset_on_fork))
+		return;
+
+	for_each_clamp_id(clamp_id) {
+		uclamp_se_set(&p->uclamp_req[clamp_id],
+			      uclamp_none(clamp_id), false);
+	}
+}
+
+static void uclamp_post_fork(struct task_struct *p)
+{
+	uclamp_update_util_min_rt_default(p);
+}
+
+static void __init init_uclamp_rq(struct rq *rq)
+{
+	enum uclamp_id clamp_id;
+	struct uclamp_rq *uc_rq = rq->uclamp;
+
+	for_each_clamp_id(clamp_id) {
+		uc_rq[clamp_id] = (struct uclamp_rq) {
+			.value = uclamp_none(clamp_id)
+		};
+	}
+
+	rq->uclamp_flags = UCLAMP_FLAG_IDLE;
+}
+
+static void __init init_uclamp(void)
+{
+	struct uclamp_se uc_max = {};
+	enum uclamp_id clamp_id;
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		init_uclamp_rq(cpu_rq(cpu));
+
+	for_each_clamp_id(clamp_id) {
+		uclamp_se_set(&init_task.uclamp_req[clamp_id],
+			      uclamp_none(clamp_id), false);
+	}
+
+	/* System defaults allow max clamp values for both indexes */
+	uclamp_se_set(&uc_max, uclamp_none(UCLAMP_MAX), false);
+	for_each_clamp_id(clamp_id) {
+		uclamp_default[clamp_id] = uc_max;
+#ifdef CONFIG_UCLAMP_TASK_GROUP
+		root_task_group.uclamp_req[clamp_id] = uc_max;
+		root_task_group.uclamp[clamp_id] = uc_max;
+#endif
+	}
+}
+
+#else /* CONFIG_UCLAMP_TASK */
+static inline void uclamp_rq_inc(struct rq *rq, struct task_struct *p) { }
+static inline void uclamp_rq_dec(struct rq *rq, struct task_struct *p) { }
+static inline int uclamp_validate(struct task_struct *p,
+				  const struct sched_attr *attr)
+{
+	return -EOPNOTSUPP;
+}
+static void __setscheduler_uclamp(struct task_struct *p,
+				  const struct sched_attr *attr) { }
+static inline void uclamp_fork(struct task_struct *p) { }
+static inline void uclamp_post_fork(struct task_struct *p) { }
+static inline void init_uclamp(void) { }
+#endif /* CONFIG_UCLAMP_TASK */
+
+bool sched_task_on_rq(struct task_struct *p)
+{
+	return task_on_rq_queued(p);
+}
+
+unsigned long get_wchan(struct task_struct *p)
+{
+	unsigned long ip = 0;
+	unsigned int state;
+
+	if (!p || p == current)
+		return 0;
+
+	/* Only get wchan if task is blocked and we can keep it that way. */
+	raw_spin_lock_irq(&p->pi_lock);
+	state = READ_ONCE(p->__state);
+	smp_rmb(); /* see try_to_wake_up() */
+	if (state != TASK_RUNNING && state != TASK_WAKING && !p->on_rq)
+		ip = __get_wchan(p);
+	raw_spin_unlock_irq(&p->pi_lock);
+
+	return ip;
+}
+
+static inline void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
+{
+	if (!(flags & ENQUEUE_NOCLOCK))
+		update_rq_clock(rq);
+
+	if (!(flags & ENQUEUE_RESTORE)) {
+		sched_info_enqueue(rq, p);
+		psi_enqueue(p, (flags & ENQUEUE_WAKEUP) && !(flags & ENQUEUE_MIGRATED));
+	}
+
+	uclamp_rq_inc(rq, p);
+	p->sched_class->enqueue_task(rq, p, flags);
+
+	if (sched_core_enabled(rq))
+		sched_core_enqueue(rq, p);
+}
+
+static inline void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
+{
+	if (sched_core_enabled(rq))
+		sched_core_dequeue(rq, p, flags);
+
+	if (!(flags & DEQUEUE_NOCLOCK))
+		update_rq_clock(rq);
+
+	if (!(flags & DEQUEUE_SAVE)) {
+		sched_info_dequeue(rq, p);
+		psi_dequeue(p, flags & DEQUEUE_SLEEP);
+	}
+
+	uclamp_rq_dec(rq, p);
+	p->sched_class->dequeue_task(rq, p, flags);
+}
+
+void activate_task(struct rq *rq, struct task_struct *p, int flags)
+{
+	if (task_on_rq_migrating(p))
+		flags |= ENQUEUE_MIGRATED;
+	if (flags & ENQUEUE_MIGRATED)
+		sched_mm_cid_migrate_to(rq, p);
+
+	enqueue_task(rq, p, flags);
+
+	p->on_rq = TASK_ON_RQ_QUEUED;
+}
+
+void deactivate_task(struct rq *rq, struct task_struct *p, int flags)
+{
+	p->on_rq = (flags & DEQUEUE_SLEEP) ? 0 : TASK_ON_RQ_MIGRATING;
+
+	dequeue_task(rq, p, flags);
+}
+
+static inline int __normal_prio(int policy, int rt_prio, int nice)
+{
+	int prio;
+
+	if (dl_policy(policy))
+		prio = MAX_DL_PRIO - 1;
+	else if (rt_policy(policy))
+		prio = MAX_RT_PRIO - 1 - rt_prio;
+	else
+		prio = NICE_TO_PRIO(nice);
+
+	return prio;
+}
+
+/*
+ * Calculate the expected normal priority: i.e. priority
+ * without taking RT-inheritance into account. Might be
+ * boosted by interactivity modifiers. Changes upon fork,
+ * setprio syscalls, and whenever the interactivity
+ * estimator recalculates.
+ */
+static inline int normal_prio(struct task_struct *p)
+{
+	return __normal_prio(p->policy, p->rt_priority, PRIO_TO_NICE(p->static_prio));
+}
+
+/*
+ * Calculate the current priority, i.e. the priority
+ * taken into account by the scheduler. This value might
+ * be boosted by RT tasks, or might be boosted by
+ * interactivity modifiers. Will be RT if the task got
+ * RT-boosted. If not then it returns p->normal_prio.
+ */
+static int effective_prio(struct task_struct *p)
+{
+	p->normal_prio = normal_prio(p);
+	/*
+	 * If we are RT tasks or we were boosted to RT priority,
+	 * keep the priority unchanged. Otherwise, update priority
+	 * to the normal priority:
+	 */
+	if (!rt_prio(p->prio))
+		return p->normal_prio;
+	return p->prio;
+}
+
+/**
+ * task_curr - is this task currently executing on a CPU?
+ * @p: the task in question.
+ *
+ * Return: 1 if the task is currently executing. 0 otherwise.
+ */
+inline int task_curr(const struct task_struct *p)
+{
+	return cpu_curr(task_cpu(p)) == p;
+}
+
+/*
+ * switched_from, switched_to and prio_changed must _NOT_ drop rq->lock,
+ * use the balance_callback list if you want balancing.
+ *
+ * this means any call to check_class_changed() must be followed by a call to
+ * balance_callback().
+ */
+static inline void check_class_changed(struct rq *rq, struct task_struct *p,
+				       const struct sched_class *prev_class,
+				       int oldprio)
+{
+	if (prev_class != p->sched_class) {
+		if (prev_class->switched_from)
+			prev_class->switched_from(rq, p);
+
+		p->sched_class->switched_to(rq, p);
+	} else if (oldprio != p->prio || dl_task(p))
+		p->sched_class->prio_changed(rq, p, oldprio);
+}
+
+void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
+{
+	if (p->sched_class == rq->curr->sched_class)
+		rq->curr->sched_class->check_preempt_curr(rq, p, flags);
+	else if (sched_class_above(p->sched_class, rq->curr->sched_class))
+		resched_curr(rq);
+
+	/*
+	 * A queue event has occurred, and we're going to schedule.  In
+	 * this case, we can save a useless back to back clock update.
+	 */
+	if (task_on_rq_queued(rq->curr) && test_tsk_need_resched(rq->curr))
+		rq_clock_skip_update(rq);
+}
+
+static __always_inline
+int __task_state_match(struct task_struct *p, unsigned int state)
+{
+	if (READ_ONCE(p->__state) & state)
+		return 1;
+
+#ifdef CONFIG_PREEMPT_RT
+	if (READ_ONCE(p->saved_state) & state)
+		return -1;
+#endif
+	return 0;
+}
+
+static __always_inline
+int task_state_match(struct task_struct *p, unsigned int state)
+{
+#ifdef CONFIG_PREEMPT_RT
+	int match;
+
+	/*
+	 * Serialize against current_save_and_set_rtlock_wait_state() and
+	 * current_restore_rtlock_saved_state().
+	 */
+	raw_spin_lock_irq(&p->pi_lock);
+	match = __task_state_match(p, state);
+	raw_spin_unlock_irq(&p->pi_lock);
+
+	return match;
+#else
+	return __task_state_match(p, state);
+#endif
+}
+
+/*
+ * wait_task_inactive - wait for a thread to unschedule.
+ *
+ * Wait for the thread to block in any of the states set in @match_state.
+ * If it changes, i.e. @p might have woken up, then return zero.  When we
+ * succeed in waiting for @p to be off its CPU, we return a positive number
+ * (its total switch count).  If a second call a short while later returns the
+ * same number, the caller can be sure that @p has remained unscheduled the
+ * whole time.
+ *
+ * The caller must ensure that the task *will* unschedule sometime soon,
+ * else this function might spin for a *long* time. This function can't
+ * be called with interrupts off, or it may introduce deadlock with
+ * smp_call_function() if an IPI is sent by the same process we are
+ * waiting to become inactive.
+ */
+unsigned long wait_task_inactive(struct task_struct *p, unsigned int match_state)
+{
+	int running, queued, match;
+	struct rq_flags rf;
+	unsigned long ncsw;
+	struct rq *rq;
+
+	for (;;) {
+		/*
+		 * We do the initial early heuristics without holding
+		 * any task-queue locks at all. We'll only try to get
+		 * the runqueue lock when things look like they will
+		 * work out!
+		 */
+		rq = task_rq(p);
+
+		/*
+		 * If the task is actively running on another CPU
+		 * still, just relax and busy-wait without holding
+		 * any locks.
+		 *
+		 * NOTE! Since we don't hold any locks, it's not
+		 * even sure that "rq" stays as the right runqueue!
+		 * But we don't care, since "task_on_cpu()" will
+		 * return false if the runqueue has changed and p
+		 * is actually now running somewhere else!
+		 */
+		while (task_on_cpu(rq, p)) {
+			if (!task_state_match(p, match_state))
+				return 0;
+			cpu_relax();
+		}
+
+		/*
+		 * Ok, time to look more closely! We need the rq
+		 * lock now, to be *sure*. If we're wrong, we'll
+		 * just go back and repeat.
+		 */
+		rq = task_rq_lock(p, &rf);
+		trace_sched_wait_task(p);
+		running = task_on_cpu(rq, p);
+		queued = task_on_rq_queued(p);
+		ncsw = 0;
+		if ((match = __task_state_match(p, match_state))) {
+			/*
+			 * When matching on p->saved_state, consider this task
+			 * still queued so it will wait.
+			 */
+			if (match < 0)
+				queued = 1;
+			ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
+		}
+		task_rq_unlock(rq, p, &rf);
+
+		/*
+		 * If it changed from the expected state, bail out now.
+		 */
+		if (unlikely(!ncsw))
+			break;
+
+		/*
+		 * Was it really running after all now that we
+		 * checked with the proper locks actually held?
+		 *
+		 * Oops. Go back and try again..
+		 */
+		if (unlikely(running)) {
+			cpu_relax();
+			continue;
+		}
+
+		/*
+		 * It's not enough that it's not actively running,
+		 * it must be off the runqueue _entirely_, and not
+		 * preempted!
+		 *
+		 * So if it was still runnable (but just not actively
+		 * running right now), it's preempted, and we should
+		 * yield - it could be a while.
+		 */
+		if (unlikely(queued)) {
+			ktime_t to = NSEC_PER_SEC / HZ;
+
+			set_current_state(TASK_UNINTERRUPTIBLE);
+			schedule_hrtimeout(&to, HRTIMER_MODE_REL_HARD);
+			continue;
+		}
+
+		/*
+		 * Ahh, all good. It wasn't running, and it wasn't
+		 * runnable, which means that it will never become
+		 * running in the future either. We're all done!
+		 */
+		break;
+	}
+
+	return ncsw;
+}
+
+#ifdef CONFIG_SMP
+
+static void
+__do_set_cpus_allowed(struct task_struct *p, struct affinity_context *ctx);
+
+static int __set_cpus_allowed_ptr(struct task_struct *p,
+				  struct affinity_context *ctx);
+
+static void migrate_disable_switch(struct rq *rq, struct task_struct *p)
+{
+	struct affinity_context ac = {
+		.new_mask  = cpumask_of(rq->cpu),
+		.flags     = SCA_MIGRATE_DISABLE,
+	};
+
+	if (likely(!p->migration_disabled))
+		return;
+
+	if (p->cpus_ptr != &p->cpus_mask)
+		return;
+
+	/*
+	 * Violates locking rules! see comment in __do_set_cpus_allowed().
+	 */
+	__do_set_cpus_allowed(p, &ac);
+}
+
+void migrate_disable(void)
+{
+	struct task_struct *p = current;
+
+	if (p->migration_disabled) {
+		p->migration_disabled++;
+		return;
+	}
+
+	preempt_disable();
+	this_rq()->nr_pinned++;
+	p->migration_disabled = 1;
+	preempt_enable();
+}
+EXPORT_SYMBOL_GPL(migrate_disable);
+
+void migrate_enable(void)
+{
+	struct task_struct *p = current;
+	struct affinity_context ac = {
+		.new_mask  = &p->cpus_mask,
+		.flags     = SCA_MIGRATE_ENABLE,
+	};
+
+	if (p->migration_disabled > 1) {
+		p->migration_disabled--;
+		return;
+	}
+
+	if (WARN_ON_ONCE(!p->migration_disabled))
+		return;
+
+	/*
+	 * Ensure stop_task runs either before or after this, and that
+	 * __set_cpus_allowed_ptr(SCA_MIGRATE_ENABLE) doesn't schedule().
+	 */
+	preempt_disable();
+	if (p->cpus_ptr != &p->cpus_mask)
+		__set_cpus_allowed_ptr(p, &ac);
+	/*
+	 * Mustn't clear migration_disabled() until cpus_ptr points back at the
+	 * regular cpus_mask, otherwise things that race (eg.
+	 * select_fallback_rq) get confused.
+	 */
+	barrier();
+	p->migration_disabled = 0;
+	this_rq()->nr_pinned--;
+	preempt_enable();
+}
+EXPORT_SYMBOL_GPL(migrate_enable);
+
+static inline bool rq_has_pinned_tasks(struct rq *rq)
+{
+	return rq->nr_pinned;
+}
+
+/*
+ * Per-CPU kthreads are allowed to run on !active && online CPUs, see
+ * __set_cpus_allowed_ptr() and select_fallback_rq().
+ */
+static inline bool is_cpu_allowed(struct task_struct *p, int cpu)
+{
+	/* When not in the task's cpumask, no point in looking further. */
+	if (!cpumask_test_cpu(cpu, p->cpus_ptr))
+		return false;
+
+	/* migrate_disabled() must be allowed to finish. */
+	if (is_migration_disabled(p))
+		return cpu_online(cpu);
+
+	/* Non kernel threads are not allowed during either online or offline. */
+	if (!(p->flags & PF_KTHREAD))
+		return cpu_active(cpu) && task_cpu_possible(cpu, p);
+
+	/* KTHREAD_IS_PER_CPU is always allowed. */
+	if (kthread_is_per_cpu(p))
+		return cpu_online(cpu);
+
+	/* Regular kernel threads don't get to stay during offline. */
+	if (cpu_dying(cpu))
+		return false;
+
+	/* But are allowed during online. */
+	return cpu_online(cpu);
+}
+
+/*
+ * This is how migration works:
+ *
+ * 1) we invoke migration_cpu_stop() on the target CPU using
+ *    stop_one_cpu().
+ * 2) stopper starts to run (implicitly forcing the migrated thread
+ *    off the CPU)
+ * 3) it checks whether the migrated task is still in the wrong runqueue.
+ * 4) if it's in the wrong runqueue then the migration thread removes
+ *    it and puts it into the right queue.
+ * 5) stopper completes and stop_one_cpu() returns and the migration
+ *    is done.
+ */
+
+/*
+ * move_queued_task - move a queued task to new rq.
+ *
+ * Returns (locked) new rq. Old rq's lock is released.
+ */
+static struct rq *move_queued_task(struct rq *rq, struct rq_flags *rf,
+				   struct task_struct *p, int new_cpu)
+{
+	lockdep_assert_rq_held(rq);
+
+	deactivate_task(rq, p, DEQUEUE_NOCLOCK);
+	set_task_cpu(p, new_cpu);
+	rq_unlock(rq, rf);
+
+	rq = cpu_rq(new_cpu);
+
+	rq_lock(rq, rf);
+	WARN_ON_ONCE(task_cpu(p) != new_cpu);
+	activate_task(rq, p, 0);
+	check_preempt_curr(rq, p, 0);
+
+	return rq;
+}
+
+struct migration_arg {
+	struct task_struct		*task;
+	int				dest_cpu;
+	struct set_affinity_pending	*pending;
+};
+
+/*
+ * @refs: number of wait_for_completion()
+ * @stop_pending: is @stop_work in use
+ */
+struct set_affinity_pending {
+	refcount_t		refs;
+	unsigned int		stop_pending;
+	struct completion	done;
+	struct cpu_stop_work	stop_work;
+	struct migration_arg	arg;
+};
+
+/*
+ * Move (not current) task off this CPU, onto the destination CPU. We're doing
+ * this because either it can't run here any more (set_cpus_allowed()
+ * away from this CPU, or CPU going down), or because we're
+ * attempting to rebalance this task on exec (sched_exec).
+ *
+ * So we race with normal scheduler movements, but that's OK, as long
+ * as the task is no longer on this CPU.
+ */
+static struct rq *__migrate_task(struct rq *rq, struct rq_flags *rf,
+				 struct task_struct *p, int dest_cpu)
+{
+	/* Affinity changed (again). */
+	if (!is_cpu_allowed(p, dest_cpu))
+		return rq;
+
+	rq = move_queued_task(rq, rf, p, dest_cpu);
+
+	return rq;
+}
+
+/*
+ * migration_cpu_stop - this will be executed by a highprio stopper thread
+ * and performs thread migration by bumping thread off CPU then
+ * 'pushing' onto another runqueue.
+ */
+static int migration_cpu_stop(void *data)
+{
+	struct migration_arg *arg = data;
+	struct set_affinity_pending *pending = arg->pending;
+	struct task_struct *p = arg->task;
+	struct rq *rq = this_rq();
+	bool complete = false;
+	struct rq_flags rf;
+
+	/*
+	 * The original target CPU might have gone down and we might
+	 * be on another CPU but it doesn't matter.
+	 */
+	local_irq_save(rf.flags);
+	/*
+	 * We need to explicitly wake pending tasks before running
+	 * __migrate_task() such that we will not miss enforcing cpus_ptr
+	 * during wakeups, see set_cpus_allowed_ptr()'s TASK_WAKING test.
+	 */
+	flush_smp_call_function_queue();
+
+	raw_spin_lock(&p->pi_lock);
+	rq_lock(rq, &rf);
+
+	/*
+	 * If we were passed a pending, then ->stop_pending was set, thus
+	 * p->migration_pending must have remained stable.
+	 */
+	WARN_ON_ONCE(pending && pending != p->migration_pending);
+
+	/*
+	 * If task_rq(p) != rq, it cannot be migrated here, because we're
+	 * holding rq->lock, if p->on_rq == 0 it cannot get enqueued because
+	 * we're holding p->pi_lock.
+	 */
+	if (task_rq(p) == rq) {
+		if (is_migration_disabled(p))
+			goto out;
+
+		if (pending) {
+			p->migration_pending = NULL;
+			complete = true;
+
+			if (cpumask_test_cpu(task_cpu(p), &p->cpus_mask))
+				goto out;
+		}
+
+		if (task_on_rq_queued(p)) {
+			update_rq_clock(rq);
+			rq = __migrate_task(rq, &rf, p, arg->dest_cpu);
+		} else {
+			p->wake_cpu = arg->dest_cpu;
+		}
+
+		/*
+		 * XXX __migrate_task() can fail, at which point we might end
+		 * up running on a dodgy CPU, AFAICT this can only happen
+		 * during CPU hotplug, at which point we'll get pushed out
+		 * anyway, so it's probably not a big deal.
+		 */
+
+	} else if (pending) {
+		/*
+		 * This happens when we get migrated between migrate_enable()'s
+		 * preempt_enable() and scheduling the stopper task. At that
+		 * point we're a regular task again and not current anymore.
+		 *
+		 * A !PREEMPT kernel has a giant hole here, which makes it far
+		 * more likely.
+		 */
+
+		/*
+		 * The task moved before the stopper got to run. We're holding
+		 * ->pi_lock, so the allowed mask is stable - if it got
+		 * somewhere allowed, we're done.
+		 */
+		if (cpumask_test_cpu(task_cpu(p), p->cpus_ptr)) {
+			p->migration_pending = NULL;
+			complete = true;
+			goto out;
+		}
+
+		/*
+		 * When migrate_enable() hits a rq mis-match we can't reliably
+		 * determine is_migration_disabled() and so have to chase after
+		 * it.
+		 */
+		WARN_ON_ONCE(!pending->stop_pending);
+		preempt_disable();
+		task_rq_unlock(rq, p, &rf);
+		stop_one_cpu_nowait(task_cpu(p), migration_cpu_stop,
+				    &pending->arg, &pending->stop_work);
+		preempt_enable();
+		return 0;
+	}
+out:
+	if (pending)
+		pending->stop_pending = false;
+	task_rq_unlock(rq, p, &rf);
+
+	if (complete)
+		complete_all(&pending->done);
+
+	return 0;
+}
+
+int push_cpu_stop(void *arg)
+{
+	struct rq *lowest_rq = NULL, *rq = this_rq();
+	struct task_struct *p = arg;
+
+	raw_spin_lock_irq(&p->pi_lock);
+	raw_spin_rq_lock(rq);
+
+	if (task_rq(p) != rq)
+		goto out_unlock;
+
+	if (is_migration_disabled(p)) {
+		p->migration_flags |= MDF_PUSH;
+		goto out_unlock;
+	}
+
+	p->migration_flags &= ~MDF_PUSH;
+
+	if (p->sched_class->find_lock_rq)
+		lowest_rq = p->sched_class->find_lock_rq(p, rq);
+
+	if (!lowest_rq)
+		goto out_unlock;
+
+	// XXX validate p is still the highest prio task
+	if (task_rq(p) == rq) {
+		deactivate_task(rq, p, 0);
+		set_task_cpu(p, lowest_rq->cpu);
+		activate_task(lowest_rq, p, 0);
+		resched_curr(lowest_rq);
+	}
+
+	double_unlock_balance(rq, lowest_rq);
+
+out_unlock:
+	rq->push_busy = false;
+	raw_spin_rq_unlock(rq);
+	raw_spin_unlock_irq(&p->pi_lock);
+
+	put_task_struct(p);
+	return 0;
+}
+
+/*
+ * sched_class::set_cpus_allowed must do the below, but is not required to
+ * actually call this function.
+ */
+void set_cpus_allowed_common(struct task_struct *p, struct affinity_context *ctx)
+{
+	if (ctx->flags & (SCA_MIGRATE_ENABLE | SCA_MIGRATE_DISABLE)) {
+		p->cpus_ptr = ctx->new_mask;
+		return;
+	}
+
+	cpumask_copy(&p->cpus_mask, ctx->new_mask);
+	p->nr_cpus_allowed = cpumask_weight(ctx->new_mask);
+
+	/*
+	 * Swap in a new user_cpus_ptr if SCA_USER flag set
+	 */
+	if (ctx->flags & SCA_USER)
+		swap(p->user_cpus_ptr, ctx->user_mask);
+}
+
+static void
+__do_set_cpus_allowed(struct task_struct *p, struct affinity_context *ctx)
+{
+	struct rq *rq = task_rq(p);
+	bool queued, running;
+
+	/*
+	 * This here violates the locking rules for affinity, since we're only
+	 * supposed to change these variables while holding both rq->lock and
+	 * p->pi_lock.
+	 *
+	 * HOWEVER, it magically works, because ttwu() is the only code that
+	 * accesses these variables under p->pi_lock and only does so after
+	 * smp_cond_load_acquire(&p->on_cpu, !VAL), and we're in __schedule()
+	 * before finish_task().
+	 *
+	 * XXX do further audits, this smells like something putrid.
+	 */
+	if (ctx->flags & SCA_MIGRATE_DISABLE)
+		SCHED_WARN_ON(!p->on_cpu);
+	else
+		lockdep_assert_held(&p->pi_lock);
+
+	queued = task_on_rq_queued(p);
+	running = task_current(rq, p);
+
+	if (queued) {
+		/*
+		 * Because __kthread_bind() calls this on blocked tasks without
+		 * holding rq->lock.
+		 */
+		lockdep_assert_rq_held(rq);
+		dequeue_task(rq, p, DEQUEUE_SAVE | DEQUEUE_NOCLOCK);
+	}
+	if (running)
+		put_prev_task(rq, p);
+
+	p->sched_class->set_cpus_allowed(p, ctx);
+
+	if (queued)
+		enqueue_task(rq, p, ENQUEUE_RESTORE | ENQUEUE_NOCLOCK);
+	if (running)
+		set_next_task(rq, p);
+}
+
+/*
+ * Used for kthread_bind() and select_fallback_rq(), in both cases the user
+ * affinity (if any) should be destroyed too.
+ */
+void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
+{
+	struct affinity_context ac = {
+		.new_mask  = new_mask,
+		.user_mask = NULL,
+		.flags     = SCA_USER,	/* clear the user requested mask */
+	};
+	union cpumask_rcuhead {
+		cpumask_t cpumask;
+		struct rcu_head rcu;
+	};
+
+	__do_set_cpus_allowed(p, &ac);
+
+	/*
+	 * Because this is called with p->pi_lock held, it is not possible
+	 * to use kfree() here (when PREEMPT_RT=y), therefore punt to using
+	 * kfree_rcu().
+	 */
+	kfree_rcu((union cpumask_rcuhead *)ac.user_mask, rcu);
+}
+
+static cpumask_t *alloc_user_cpus_ptr(int node)
+{
+	/*
+	 * See do_set_cpus_allowed() above for the rcu_head usage.
+	 */
+	int size = max_t(int, cpumask_size(), sizeof(struct rcu_head));
+
+	return kmalloc_node(size, GFP_KERNEL, node);
+}
+
+int dup_user_cpus_ptr(struct task_struct *dst, struct task_struct *src,
+		      int node)
+{
+	cpumask_t *user_mask;
+	unsigned long flags;
+
+	/*
+	 * Always clear dst->user_cpus_ptr first as their user_cpus_ptr's
+	 * may differ by now due to racing.
+	 */
+	dst->user_cpus_ptr = NULL;
+
+	/*
+	 * This check is racy and losing the race is a valid situation.
+	 * It is not worth the extra overhead of taking the pi_lock on
+	 * every fork/clone.
+	 */
+	if (data_race(!src->user_cpus_ptr))
+		return 0;
+
+	user_mask = alloc_user_cpus_ptr(node);
+	if (!user_mask)
+		return -ENOMEM;
+
+	/*
+	 * Use pi_lock to protect content of user_cpus_ptr
+	 *
+	 * Though unlikely, user_cpus_ptr can be reset to NULL by a concurrent
+	 * do_set_cpus_allowed().
+	 */
+	raw_spin_lock_irqsave(&src->pi_lock, flags);
+	if (src->user_cpus_ptr) {
+		swap(dst->user_cpus_ptr, user_mask);
+		cpumask_copy(dst->user_cpus_ptr, src->user_cpus_ptr);
+	}
+	raw_spin_unlock_irqrestore(&src->pi_lock, flags);
+
+	if (unlikely(user_mask))
+		kfree(user_mask);
+
+	return 0;
+}
+
+static inline struct cpumask *clear_user_cpus_ptr(struct task_struct *p)
+{
+	struct cpumask *user_mask = NULL;
+
+	swap(p->user_cpus_ptr, user_mask);
+
+	return user_mask;
+}
+
+void release_user_cpus_ptr(struct task_struct *p)
+{
+	kfree(clear_user_cpus_ptr(p));
+}
+
+/*
+ * This function is wildly self concurrent; here be dragons.
+ *
+ *
+ * When given a valid mask, __set_cpus_allowed_ptr() must block until the
+ * designated task is enqueued on an allowed CPU. If that task is currently
+ * running, we have to kick it out using the CPU stopper.
+ *
+ * Migrate-Disable comes along and tramples all over our nice sandcastle.
+ * Consider:
+ *
+ *     Initial conditions: P0->cpus_mask = [0, 1]
+ *
+ *     P0@CPU0                  P1
+ *
+ *     migrate_disable();
+ *     <preempted>
+ *                              set_cpus_allowed_ptr(P0, [1]);
+ *
+ * P1 *cannot* return from this set_cpus_allowed_ptr() call until P0 executes
+ * its outermost migrate_enable() (i.e. it exits its Migrate-Disable region).
+ * This means we need the following scheme:
+ *
+ *     P0@CPU0                  P1
+ *
+ *     migrate_disable();
+ *     <preempted>
+ *                              set_cpus_allowed_ptr(P0, [1]);
+ *                                <blocks>
+ *     <resumes>
+ *     migrate_enable();
+ *       __set_cpus_allowed_ptr();
+ *       <wakes local stopper>
+ *                         `--> <woken on migration completion>
+ *
+ * Now the fun stuff: there may be several P1-like tasks, i.e. multiple
+ * concurrent set_cpus_allowed_ptr(P0, [*]) calls. CPU affinity changes of any
+ * task p are serialized by p->pi_lock, which we can leverage: the one that
+ * should come into effect at the end of the Migrate-Disable region is the last
+ * one. This means we only need to track a single cpumask (i.e. p->cpus_mask),
+ * but we still need to properly signal those waiting tasks at the appropriate
+ * moment.
+ *
+ * This is implemented using struct set_affinity_pending. The first
+ * __set_cpus_allowed_ptr() caller within a given Migrate-Disable region will
+ * setup an instance of that struct and install it on the targeted task_struct.
+ * Any and all further callers will reuse that instance. Those then wait for
+ * a completion signaled at the tail of the CPU stopper callback (1), triggered
+ * on the end of the Migrate-Disable region (i.e. outermost migrate_enable()).
+ *
+ *
+ * (1) In the cases covered above. There is one more where the completion is
+ * signaled within affine_move_task() itself: when a subsequent affinity request
+ * occurs after the stopper bailed out due to the targeted task still being
+ * Migrate-Disable. Consider:
+ *
+ *     Initial conditions: P0->cpus_mask = [0, 1]
+ *
+ *     CPU0		  P1				P2
+ *     <P0>
+ *       migrate_disable();
+ *       <preempted>
+ *                        set_cpus_allowed_ptr(P0, [1]);
+ *                          <blocks>
+ *     <migration/0>
+ *       migration_cpu_stop()
+ *         is_migration_disabled()
+ *           <bails>
+ *                                                       set_cpus_allowed_ptr(P0, [0, 1]);
+ *                                                         <signal completion>
+ *                          <awakes>
+ *
+ * Note that the above is safe vs a concurrent migrate_enable(), as any
+ * pending affinity completion is preceded by an uninstallation of
+ * p->migration_pending done with p->pi_lock held.
+ */
+static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flags *rf,
+			    int dest_cpu, unsigned int flags)
+	__releases(rq->lock)
+	__releases(p->pi_lock)
+{
+	struct set_affinity_pending my_pending = { }, *pending = NULL;
+	bool stop_pending, complete = false;
+
+	/* Can the task run on the task's current CPU? If so, we're done */
+	if (cpumask_test_cpu(task_cpu(p), &p->cpus_mask)) {
+		struct task_struct *push_task = NULL;
+
+		if ((flags & SCA_MIGRATE_ENABLE) &&
+		    (p->migration_flags & MDF_PUSH) && !rq->push_busy) {
+			rq->push_busy = true;
+			push_task = get_task_struct(p);
+		}
+
+		/*
+		 * If there are pending waiters, but no pending stop_work,
+		 * then complete now.
+		 */
+		pending = p->migration_pending;
+		if (pending && !pending->stop_pending) {
+			p->migration_pending = NULL;
+			complete = true;
+		}
+
+		preempt_disable();
+		task_rq_unlock(rq, p, rf);
+		if (push_task) {
+			stop_one_cpu_nowait(rq->cpu, push_cpu_stop,
+					    p, &rq->push_work);
+		}
+		preempt_enable();
+
+		if (complete)
+			complete_all(&pending->done);
+
+		return 0;
+	}
+
+	if (!(flags & SCA_MIGRATE_ENABLE)) {
+		/* serialized by p->pi_lock */
+		if (!p->migration_pending) {
+			/* Install the request */
+			refcount_set(&my_pending.refs, 1);
+			init_completion(&my_pending.done);
+			my_pending.arg = (struct migration_arg) {
+				.task = p,
+				.dest_cpu = dest_cpu,
+				.pending = &my_pending,
+			};
+
+			p->migration_pending = &my_pending;
+		} else {
+			pending = p->migration_pending;
+			refcount_inc(&pending->refs);
+			/*
+			 * Affinity has changed, but we've already installed a
+			 * pending. migration_cpu_stop() *must* see this, else
+			 * we risk a completion of the pending despite having a
+			 * task on a disallowed CPU.
+			 *
+			 * Serialized by p->pi_lock, so this is safe.
+			 */
+			pending->arg.dest_cpu = dest_cpu;
+		}
+	}
+	pending = p->migration_pending;
+	/*
+	 * - !MIGRATE_ENABLE:
+	 *   we'll have installed a pending if there wasn't one already.
+	 *
+	 * - MIGRATE_ENABLE:
+	 *   we're here because the current CPU isn't matching anymore,
+	 *   the only way that can happen is because of a concurrent
+	 *   set_cpus_allowed_ptr() call, which should then still be
+	 *   pending completion.
+	 *
+	 * Either way, we really should have a @pending here.
+	 */
+	if (WARN_ON_ONCE(!pending)) {
+		task_rq_unlock(rq, p, rf);
+		return -EINVAL;
+	}
+
+	if (task_on_cpu(rq, p) || READ_ONCE(p->__state) == TASK_WAKING) {
+		/*
+		 * MIGRATE_ENABLE gets here because 'p == current', but for
+		 * anything else we cannot do is_migration_disabled(), punt
+		 * and have the stopper function handle it all race-free.
+		 */
+		stop_pending = pending->stop_pending;
+		if (!stop_pending)
+			pending->stop_pending = true;
+
+		if (flags & SCA_MIGRATE_ENABLE)
+			p->migration_flags &= ~MDF_PUSH;
+
+		preempt_disable();
+		task_rq_unlock(rq, p, rf);
+		if (!stop_pending) {
+			stop_one_cpu_nowait(cpu_of(rq), migration_cpu_stop,
+					    &pending->arg, &pending->stop_work);
+		}
+		preempt_enable();
+
+		if (flags & SCA_MIGRATE_ENABLE)
+			return 0;
+	} else {
+
+		if (!is_migration_disabled(p)) {
+			if (task_on_rq_queued(p))
+				rq = move_queued_task(rq, rf, p, dest_cpu);
+
+			if (!pending->stop_pending) {
+				p->migration_pending = NULL;
+				complete = true;
+			}
+		}
+		task_rq_unlock(rq, p, rf);
+
+		if (complete)
+			complete_all(&pending->done);
+	}
+
+	wait_for_completion(&pending->done);
+
+	if (refcount_dec_and_test(&pending->refs))
+		wake_up_var(&pending->refs); /* No UaF, just an address */
+
+	/*
+	 * Block the original owner of &pending until all subsequent callers
+	 * have seen the completion and decremented the refcount
+	 */
+	wait_var_event(&my_pending.refs, !refcount_read(&my_pending.refs));
+
+	/* ARGH */
+	WARN_ON_ONCE(my_pending.stop_pending);
+
+	return 0;
+}
+
+/*
+ * Called with both p->pi_lock and rq->lock held; drops both before returning.
+ */
+static int __set_cpus_allowed_ptr_locked(struct task_struct *p,
+					 struct affinity_context *ctx,
+					 struct rq *rq,
+					 struct rq_flags *rf)
+	__releases(rq->lock)
+	__releases(p->pi_lock)
+{
+	const struct cpumask *cpu_allowed_mask = task_cpu_possible_mask(p);
+	const struct cpumask *cpu_valid_mask = cpu_active_mask;
+	bool kthread = p->flags & PF_KTHREAD;
+	unsigned int dest_cpu;
+	int ret = 0;
+
+	update_rq_clock(rq);
+
+	if (kthread || is_migration_disabled(p)) {
+		/*
+		 * Kernel threads are allowed on online && !active CPUs,
+		 * however, during cpu-hot-unplug, even these might get pushed
+		 * away if not KTHREAD_IS_PER_CPU.
+		 *
+		 * Specifically, migration_disabled() tasks must not fail the
+		 * cpumask_any_and_distribute() pick below, esp. so on
+		 * SCA_MIGRATE_ENABLE, otherwise we'll not call
+		 * set_cpus_allowed_common() and actually reset p->cpus_ptr.
+		 */
+		cpu_valid_mask = cpu_online_mask;
+	}
+
+	if (!kthread && !cpumask_subset(ctx->new_mask, cpu_allowed_mask)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/*
+	 * Must re-check here, to close a race against __kthread_bind(),
+	 * sched_setaffinity() is not guaranteed to observe the flag.
+	 */
+	if ((ctx->flags & SCA_CHECK) && (p->flags & PF_NO_SETAFFINITY)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (!(ctx->flags & SCA_MIGRATE_ENABLE)) {
+		if (cpumask_equal(&p->cpus_mask, ctx->new_mask)) {
+			if (ctx->flags & SCA_USER)
+				swap(p->user_cpus_ptr, ctx->user_mask);
+			goto out;
+		}
+
+		if (WARN_ON_ONCE(p == current &&
+				 is_migration_disabled(p) &&
+				 !cpumask_test_cpu(task_cpu(p), ctx->new_mask))) {
+			ret = -EBUSY;
+			goto out;
+		}
+	}
+
+	/*
+	 * Picking a ~random cpu helps in cases where we are changing affinity
+	 * for groups of tasks (ie. cpuset), so that load balancing is not
+	 * immediately required to distribute the tasks within their new mask.
+	 */
+	dest_cpu = cpumask_any_and_distribute(cpu_valid_mask, ctx->new_mask);
+	if (dest_cpu >= nr_cpu_ids) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	__do_set_cpus_allowed(p, ctx);
+
+	return affine_move_task(rq, p, rf, dest_cpu, ctx->flags);
+
+out:
+	task_rq_unlock(rq, p, rf);
+
+	return ret;
+}
+
+/*
+ * Change a given task's CPU affinity. Migrate the thread to a
+ * proper CPU and schedule it away if the CPU it's executing on
+ * is removed from the allowed bitmask.
+ *
+ * NOTE: the caller must have a valid reference to the task, the
+ * task must not exit() & deallocate itself prematurely. The
+ * call is not atomic; no spinlocks may be held.
+ */
+static int __set_cpus_allowed_ptr(struct task_struct *p,
+				  struct affinity_context *ctx)
+{
+	struct rq_flags rf;
+	struct rq *rq;
+
+	rq = task_rq_lock(p, &rf);
+	/*
+	 * Masking should be skipped if SCA_USER or any of the SCA_MIGRATE_*
+	 * flags are set.
+	 */
+	if (p->user_cpus_ptr &&
+	    !(ctx->flags & (SCA_USER | SCA_MIGRATE_ENABLE | SCA_MIGRATE_DISABLE)) &&
+	    cpumask_and(rq->scratch_mask, ctx->new_mask, p->user_cpus_ptr))
+		ctx->new_mask = rq->scratch_mask;
+
+	return __set_cpus_allowed_ptr_locked(p, ctx, rq, &rf);
+}
+
+int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
+{
+	struct affinity_context ac = {
+		.new_mask  = new_mask,
+		.flags     = 0,
+	};
+
+	return __set_cpus_allowed_ptr(p, &ac);
+}
+EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
+
+/*
+ * Change a given task's CPU affinity to the intersection of its current
+ * affinity mask and @subset_mask, writing the resulting mask to @new_mask.
+ * If user_cpus_ptr is defined, use it as the basis for restricting CPU
+ * affinity or use cpu_online_mask instead.
+ *
+ * If the resulting mask is empty, leave the affinity unchanged and return
+ * -EINVAL.
+ */
+static int restrict_cpus_allowed_ptr(struct task_struct *p,
+				     struct cpumask *new_mask,
+				     const struct cpumask *subset_mask)
+{
+	struct affinity_context ac = {
+		.new_mask  = new_mask,
+		.flags     = 0,
+	};
+	struct rq_flags rf;
+	struct rq *rq;
+	int err;
+
+	rq = task_rq_lock(p, &rf);
+
+	/*
+	 * Forcefully restricting the affinity of a deadline task is
+	 * likely to cause problems, so fail and noisily override the
+	 * mask entirely.
+	 */
+	if (task_has_dl_policy(p) && dl_bandwidth_enabled()) {
+		err = -EPERM;
+		goto err_unlock;
+	}
+
+	if (!cpumask_and(new_mask, task_user_cpus(p), subset_mask)) {
+		err = -EINVAL;
+		goto err_unlock;
+	}
+
+	return __set_cpus_allowed_ptr_locked(p, &ac, rq, &rf);
+
+err_unlock:
+	task_rq_unlock(rq, p, &rf);
+	return err;
+}
+
+/*
+ * Restrict the CPU affinity of task @p so that it is a subset of
+ * task_cpu_possible_mask() and point @p->user_cpus_ptr to a copy of the
+ * old affinity mask. If the resulting mask is empty, we warn and walk
+ * up the cpuset hierarchy until we find a suitable mask.
+ */
+void force_compatible_cpus_allowed_ptr(struct task_struct *p)
+{
+	cpumask_var_t new_mask;
+	const struct cpumask *override_mask = task_cpu_possible_mask(p);
+
+	alloc_cpumask_var(&new_mask, GFP_KERNEL);
+
+	/*
+	 * __migrate_task() can fail silently in the face of concurrent
+	 * offlining of the chosen destination CPU, so take the hotplug
+	 * lock to ensure that the migration succeeds.
+	 */
+	cpus_read_lock();
+	if (!cpumask_available(new_mask))
+		goto out_set_mask;
+
+	if (!restrict_cpus_allowed_ptr(p, new_mask, override_mask))
+		goto out_free_mask;
+
+	/*
+	 * We failed to find a valid subset of the affinity mask for the
+	 * task, so override it based on its cpuset hierarchy.
+	 */
+	cpuset_cpus_allowed(p, new_mask);
+	override_mask = new_mask;
+
+out_set_mask:
+	if (printk_ratelimit()) {
+		printk_deferred("Overriding affinity for process %d (%s) to CPUs %*pbl\n",
+				task_pid_nr(p), p->comm,
+				cpumask_pr_args(override_mask));
+	}
+
+	WARN_ON(set_cpus_allowed_ptr(p, override_mask));
+out_free_mask:
+	cpus_read_unlock();
+	free_cpumask_var(new_mask);
+}
+
+static int
+__sched_setaffinity(struct task_struct *p, struct affinity_context *ctx);
+
+/*
+ * Restore the affinity of a task @p which was previously restricted by a
+ * call to force_compatible_cpus_allowed_ptr().
+ *
+ * It is the caller's responsibility to serialise this with any calls to
+ * force_compatible_cpus_allowed_ptr(@p).
+ */
+void relax_compatible_cpus_allowed_ptr(struct task_struct *p)
+{
+	struct affinity_context ac = {
+		.new_mask  = task_user_cpus(p),
+		.flags     = 0,
+	};
+	int ret;
+
+	/*
+	 * Try to restore the old affinity mask with __sched_setaffinity().
+	 * Cpuset masking will be done there too.
+	 */
+	ret = __sched_setaffinity(p, &ac);
+	WARN_ON_ONCE(ret);
+}
+
+void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
+{
+#ifdef CONFIG_SCHED_DEBUG
+	unsigned int state = READ_ONCE(p->__state);
+
+	/*
+	 * We should never call set_task_cpu() on a blocked task,
+	 * ttwu() will sort out the placement.
+	 */
+	WARN_ON_ONCE(state != TASK_RUNNING && state != TASK_WAKING && !p->on_rq);
+
+	/*
+	 * Migrating fair class task must have p->on_rq = TASK_ON_RQ_MIGRATING,
+	 * because schedstat_wait_{start,end} rebase migrating task's wait_start
+	 * time relying on p->on_rq.
+	 */
+	WARN_ON_ONCE(state == TASK_RUNNING &&
+		     p->sched_class == &fair_sched_class &&
+		     (p->on_rq && !task_on_rq_migrating(p)));
+
+#ifdef CONFIG_LOCKDEP
+	/*
+	 * The caller should hold either p->pi_lock or rq->lock, when changing
+	 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
+	 *
+	 * sched_move_task() holds both and thus holding either pins the cgroup,
+	 * see task_group().
+	 *
+	 * Furthermore, all task_rq users should acquire both locks, see
+	 * task_rq_lock().
+	 */
+	WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) ||
+				      lockdep_is_held(__rq_lockp(task_rq(p)))));
+#endif
+	/*
+	 * Clearly, migrating tasks to offline CPUs is a fairly daft thing.
+	 */
+	WARN_ON_ONCE(!cpu_online(new_cpu));
+
+	WARN_ON_ONCE(is_migration_disabled(p));
+#endif
+
+	trace_sched_migrate_task(p, new_cpu);
+
+	if (task_cpu(p) != new_cpu) {
+		if (p->sched_class->migrate_task_rq)
+			p->sched_class->migrate_task_rq(p, new_cpu);
+		p->se.nr_migrations++;
+		rseq_migrate(p);
+		sched_mm_cid_migrate_from(p);
+		perf_event_task_migrate(p);
+	}
+
+	__set_task_cpu(p, new_cpu);
+}
+
+#ifdef CONFIG_NUMA_BALANCING
+static void __migrate_swap_task(struct task_struct *p, int cpu)
+{
+	if (task_on_rq_queued(p)) {
+		struct rq *src_rq, *dst_rq;
+		struct rq_flags srf, drf;
+
+		src_rq = task_rq(p);
+		dst_rq = cpu_rq(cpu);
+
+		rq_pin_lock(src_rq, &srf);
+		rq_pin_lock(dst_rq, &drf);
+
+		deactivate_task(src_rq, p, 0);
+		set_task_cpu(p, cpu);
+		activate_task(dst_rq, p, 0);
+		check_preempt_curr(dst_rq, p, 0);
+
+		rq_unpin_lock(dst_rq, &drf);
+		rq_unpin_lock(src_rq, &srf);
+
+	} else {
+		/*
+		 * Task isn't running anymore; make it appear like we migrated
+		 * it before it went to sleep. This means on wakeup we make the
+		 * previous CPU our target instead of where it really is.
+		 */
+		p->wake_cpu = cpu;
+	}
+}
+
+struct migration_swap_arg {
+	struct task_struct *src_task, *dst_task;
+	int src_cpu, dst_cpu;
+};
+
+static int migrate_swap_stop(void *data)
+{
+	struct migration_swap_arg *arg = data;
+	struct rq *src_rq, *dst_rq;
+
+	if (!cpu_active(arg->src_cpu) || !cpu_active(arg->dst_cpu))
+		return -EAGAIN;
+
+	src_rq = cpu_rq(arg->src_cpu);
+	dst_rq = cpu_rq(arg->dst_cpu);
+
+	guard(double_raw_spinlock)(&arg->src_task->pi_lock, &arg->dst_task->pi_lock);
+	guard(double_rq_lock)(src_rq, dst_rq);
+
+	if (task_cpu(arg->dst_task) != arg->dst_cpu)
+		return -EAGAIN;
+
+	if (task_cpu(arg->src_task) != arg->src_cpu)
+		return -EAGAIN;
+
+	if (!cpumask_test_cpu(arg->dst_cpu, arg->src_task->cpus_ptr))
+		return -EAGAIN;
+
+	if (!cpumask_test_cpu(arg->src_cpu, arg->dst_task->cpus_ptr))
+		return -EAGAIN;
+
+	__migrate_swap_task(arg->src_task, arg->dst_cpu);
+	__migrate_swap_task(arg->dst_task, arg->src_cpu);
+
+	return 0;
+}
+
+/*
+ * Cross migrate two tasks
+ */
+int migrate_swap(struct task_struct *cur, struct task_struct *p,
+		int target_cpu, int curr_cpu)
+{
+	struct migration_swap_arg arg;
+	int ret = -EINVAL;
+
+	arg = (struct migration_swap_arg){
+		.src_task = cur,
+		.src_cpu = curr_cpu,
+		.dst_task = p,
+		.dst_cpu = target_cpu,
+	};
+
+	if (arg.src_cpu == arg.dst_cpu)
+		goto out;
+
+	/*
+	 * These three tests are all lockless; this is OK since all of them
+	 * will be re-checked with proper locks held further down the line.
+	 */
+	if (!cpu_active(arg.src_cpu) || !cpu_active(arg.dst_cpu))
+		goto out;
+
+	if (!cpumask_test_cpu(arg.dst_cpu, arg.src_task->cpus_ptr))
+		goto out;
+
+	if (!cpumask_test_cpu(arg.src_cpu, arg.dst_task->cpus_ptr))
+		goto out;
+
+	trace_sched_swap_numa(cur, arg.src_cpu, p, arg.dst_cpu);
+	ret = stop_two_cpus(arg.dst_cpu, arg.src_cpu, migrate_swap_stop, &arg);
+
+out:
+	return ret;
+}
+#endif /* CONFIG_NUMA_BALANCING */
+
+/***
+ * kick_process - kick a running thread to enter/exit the kernel
+ * @p: the to-be-kicked thread
+ *
+ * Cause a process which is running on another CPU to enter
+ * kernel-mode, without any delay. (to get signals handled.)
+ *
+ * NOTE: this function doesn't have to take the runqueue lock,
+ * because all it wants to ensure is that the remote task enters
+ * the kernel. If the IPI races and the task has been migrated
+ * to another CPU then no harm is done and the purpose has been
+ * achieved as well.
+ */
+void kick_process(struct task_struct *p)
+{
+	int cpu;
+
+	preempt_disable();
+	cpu = task_cpu(p);
+	if ((cpu != smp_processor_id()) && task_curr(p))
+		smp_send_reschedule(cpu);
+	preempt_enable();
+}
+EXPORT_SYMBOL_GPL(kick_process);
+
+/*
+ * ->cpus_ptr is protected by both rq->lock and p->pi_lock
+ *
+ * A few notes on cpu_active vs cpu_online:
+ *
+ *  - cpu_active must be a subset of cpu_online
+ *
+ *  - on CPU-up we allow per-CPU kthreads on the online && !active CPU,
+ *    see __set_cpus_allowed_ptr(). At this point the newly online
+ *    CPU isn't yet part of the sched domains, and balancing will not
+ *    see it.
+ *
+ *  - on CPU-down we clear cpu_active() to mask the sched domains and
+ *    avoid the load balancer to place new tasks on the to be removed
+ *    CPU. Existing tasks will remain running there and will be taken
+ *    off.
+ *
+ * This means that fallback selection must not select !active CPUs.
+ * And can assume that any active CPU must be online. Conversely
+ * select_task_rq() below may allow selection of !active CPUs in order
+ * to satisfy the above rules.
+ */
+static int select_fallback_rq(int cpu, struct task_struct *p)
+{
+	int nid = cpu_to_node(cpu);
+	const struct cpumask *nodemask = NULL;
+	enum { cpuset, possible, fail } state = cpuset;
+	int dest_cpu;
+
+	/*
+	 * If the node that the CPU is on has been offlined, cpu_to_node()
+	 * will return -1. There is no CPU on the node, and we should
+	 * select the CPU on the other node.
+	 */
+	if (nid != -1) {
+		nodemask = cpumask_of_node(nid);
+
+		/* Look for allowed, online CPU in same node. */
+		for_each_cpu(dest_cpu, nodemask) {
+			if (is_cpu_allowed(p, dest_cpu))
+				return dest_cpu;
+		}
+	}
+
+	for (;;) {
+		/* Any allowed, online CPU? */
+		for_each_cpu(dest_cpu, p->cpus_ptr) {
+			if (!is_cpu_allowed(p, dest_cpu))
+				continue;
+
+			goto out;
+		}
+
+		/* No more Mr. Nice Guy. */
+		switch (state) {
+		case cpuset:
+			if (cpuset_cpus_allowed_fallback(p)) {
+				state = possible;
+				break;
+			}
+			fallthrough;
+		case possible:
+			/*
+			 * XXX When called from select_task_rq() we only
+			 * hold p->pi_lock and again violate locking order.
+			 *
+			 * More yuck to audit.
+			 */
+			do_set_cpus_allowed(p, task_cpu_possible_mask(p));
+			state = fail;
+			break;
+		case fail:
+			BUG();
+			break;
+		}
+	}
+
+out:
+	if (state != cpuset) {
+		/*
+		 * Don't tell them about moving exiting tasks or
+		 * kernel threads (both mm NULL), since they never
+		 * leave kernel.
+		 */
+		if (p->mm && printk_ratelimit()) {
+			printk_deferred("process %d (%s) no longer affine to cpu%d\n",
+					task_pid_nr(p), p->comm, cpu);
+		}
+	}
+
+	return dest_cpu;
+}
+
+/*
+ * The caller (fork, wakeup) owns p->pi_lock, ->cpus_ptr is stable.
+ */
+static inline
+int select_task_rq(struct task_struct *p, int cpu, int wake_flags)
+{
+	lockdep_assert_held(&p->pi_lock);
+
+	if (p->nr_cpus_allowed > 1 && !is_migration_disabled(p))
+		cpu = p->sched_class->select_task_rq(p, cpu, wake_flags);
+	else
+		cpu = cpumask_any(p->cpus_ptr);
+
+	/*
+	 * In order not to call set_task_cpu() on a blocking task we need
+	 * to rely on ttwu() to place the task on a valid ->cpus_ptr
+	 * CPU.
+	 *
+	 * Since this is common to all placement strategies, this lives here.
+	 *
+	 * [ this allows ->select_task() to simply return task_cpu(p) and
+	 *   not worry about this generic constraint ]
+	 */
+	if (unlikely(!is_cpu_allowed(p, cpu)))
+		cpu = select_fallback_rq(task_cpu(p), p);
+
+	return cpu;
+}
+
+void sched_set_stop_task(int cpu, struct task_struct *stop)
+{
+	static struct lock_class_key stop_pi_lock;
+	struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
+	struct task_struct *old_stop = cpu_rq(cpu)->stop;
+
+	if (stop) {
+		/*
+		 * Make it appear like a SCHED_FIFO task, its something
+		 * userspace knows about and won't get confused about.
+		 *
+		 * Also, it will make PI more or less work without too
+		 * much confusion -- but then, stop work should not
+		 * rely on PI working anyway.
+		 */
+		sched_setscheduler_nocheck(stop, SCHED_FIFO, &param);
+
+		stop->sched_class = &stop_sched_class;
+
+		/*
+		 * The PI code calls rt_mutex_setprio() with ->pi_lock held to
+		 * adjust the effective priority of a task. As a result,
+		 * rt_mutex_setprio() can trigger (RT) balancing operations,
+		 * which can then trigger wakeups of the stop thread to push
+		 * around the current task.
+		 *
+		 * The stop task itself will never be part of the PI-chain, it
+		 * never blocks, therefore that ->pi_lock recursion is safe.
+		 * Tell lockdep about this by placing the stop->pi_lock in its
+		 * own class.
+		 */
+		lockdep_set_class(&stop->pi_lock, &stop_pi_lock);
+	}
+
+	cpu_rq(cpu)->stop = stop;
+
+	if (old_stop) {
+		/*
+		 * Reset it back to a normal scheduling class so that
+		 * it can die in pieces.
+		 */
+		old_stop->sched_class = &rt_sched_class;
+	}
+}
+
+#else /* CONFIG_SMP */
+
+static inline int __set_cpus_allowed_ptr(struct task_struct *p,
+					 struct affinity_context *ctx)
+{
+	return set_cpus_allowed_ptr(p, ctx->new_mask);
+}
+
+static inline void migrate_disable_switch(struct rq *rq, struct task_struct *p) { }
+
+static inline bool rq_has_pinned_tasks(struct rq *rq)
+{
+	return false;
+}
+
+static inline cpumask_t *alloc_user_cpus_ptr(int node)
+{
+	return NULL;
+}
+
+#endif /* !CONFIG_SMP */
+
+static void
+ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
+{
+	struct rq *rq;
+
+	if (!schedstat_enabled())
+		return;
+
+	rq = this_rq();
+
+#ifdef CONFIG_SMP
+	if (cpu == rq->cpu) {
+		__schedstat_inc(rq->ttwu_local);
+		__schedstat_inc(p->stats.nr_wakeups_local);
+	} else {
+		struct sched_domain *sd;
+
+		__schedstat_inc(p->stats.nr_wakeups_remote);
+
+		guard(rcu)();
+		for_each_domain(rq->cpu, sd) {
+			if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
+				__schedstat_inc(sd->ttwu_wake_remote);
+				break;
+			}
+		}
+	}
+
+	if (wake_flags & WF_MIGRATED)
+		__schedstat_inc(p->stats.nr_wakeups_migrate);
+#endif /* CONFIG_SMP */
+
+	__schedstat_inc(rq->ttwu_count);
+	__schedstat_inc(p->stats.nr_wakeups);
+
+	if (wake_flags & WF_SYNC)
+		__schedstat_inc(p->stats.nr_wakeups_sync);
+}
+
+/*
+ * Mark the task runnable.
+ */
+static inline void ttwu_do_wakeup(struct task_struct *p)
+{
+	WRITE_ONCE(p->__state, TASK_RUNNING);
+	trace_sched_wakeup(p);
+}
+
+static void
+ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags,
+		 struct rq_flags *rf)
+{
+	int en_flags = ENQUEUE_WAKEUP | ENQUEUE_NOCLOCK;
+
+	lockdep_assert_rq_held(rq);
+
+	if (p->sched_contributes_to_load)
+		rq->nr_uninterruptible--;
+
+#ifdef CONFIG_SMP
+	if (wake_flags & WF_MIGRATED)
+		en_flags |= ENQUEUE_MIGRATED;
+	else
+#endif
+	if (p->in_iowait) {
+		delayacct_blkio_end(p);
+		atomic_dec(&task_rq(p)->nr_iowait);
+	}
+
+	activate_task(rq, p, en_flags);
+	check_preempt_curr(rq, p, wake_flags);
+
+	ttwu_do_wakeup(p);
+
+#ifdef CONFIG_SMP
+	if (p->sched_class->task_woken) {
+		/*
+		 * Our task @p is fully woken up and running; so it's safe to
+		 * drop the rq->lock, hereafter rq is only used for statistics.
+		 */
+		rq_unpin_lock(rq, rf);
+		p->sched_class->task_woken(rq, p);
+		rq_repin_lock(rq, rf);
+	}
+
+	if (rq->idle_stamp) {
+		u64 delta = rq_clock(rq) - rq->idle_stamp;
+		u64 max = 2*rq->max_idle_balance_cost;
+
+		update_avg(&rq->avg_idle, delta);
+
+		if (rq->avg_idle > max)
+			rq->avg_idle = max;
+
+		rq->wake_stamp = jiffies;
+		rq->wake_avg_idle = rq->avg_idle / 2;
+
+		rq->idle_stamp = 0;
+	}
+#endif
+}
+
+/*
+ * Consider @p being inside a wait loop:
+ *
+ *   for (;;) {
+ *      set_current_state(TASK_UNINTERRUPTIBLE);
+ *
+ *      if (CONDITION)
+ *         break;
+ *
+ *      schedule();
+ *   }
+ *   __set_current_state(TASK_RUNNING);
+ *
+ * between set_current_state() and schedule(). In this case @p is still
+ * runnable, so all that needs doing is change p->state back to TASK_RUNNING in
+ * an atomic manner.
+ *
+ * By taking task_rq(p)->lock we serialize against schedule(), if @p->on_rq
+ * then schedule() must still happen and p->state can be changed to
+ * TASK_RUNNING. Otherwise we lost the race, schedule() has happened, and we
+ * need to do a full wakeup with enqueue.
+ *
+ * Returns: %true when the wakeup is done,
+ *          %false otherwise.
+ */
+static int ttwu_runnable(struct task_struct *p, int wake_flags)
+{
+	struct rq_flags rf;
+	struct rq *rq;
+	int ret = 0;
+
+	rq = __task_rq_lock(p, &rf);
+	if (task_on_rq_queued(p)) {
+		if (!task_on_cpu(rq, p)) {
+			/*
+			 * When on_rq && !on_cpu the task is preempted, see if
+			 * it should preempt the task that is current now.
+			 */
+			update_rq_clock(rq);
+			check_preempt_curr(rq, p, wake_flags);
+		}
+		ttwu_do_wakeup(p);
+		ret = 1;
+	}
+	__task_rq_unlock(rq, &rf);
+
+	return ret;
+}
+
+#ifdef CONFIG_SMP
+void sched_ttwu_pending(void *arg)
+{
+	struct llist_node *llist = arg;
+	struct rq *rq = this_rq();
+	struct task_struct *p, *t;
+	struct rq_flags rf;
+
+	if (!llist)
+		return;
+
+	rq_lock_irqsave(rq, &rf);
+	update_rq_clock(rq);
+
+	llist_for_each_entry_safe(p, t, llist, wake_entry.llist) {
+		if (WARN_ON_ONCE(p->on_cpu))
+			smp_cond_load_acquire(&p->on_cpu, !VAL);
+
+		if (WARN_ON_ONCE(task_cpu(p) != cpu_of(rq)))
+			set_task_cpu(p, cpu_of(rq));
+
+		ttwu_do_activate(rq, p, p->sched_remote_wakeup ? WF_MIGRATED : 0, &rf);
+	}
+
+	/*
+	 * Must be after enqueueing at least once task such that
+	 * idle_cpu() does not observe a false-negative -- if it does,
+	 * it is possible for select_idle_siblings() to stack a number
+	 * of tasks on this CPU during that window.
+	 *
+	 * It is ok to clear ttwu_pending when another task pending.
+	 * We will receive IPI after local irq enabled and then enqueue it.
+	 * Since now nr_running > 0, idle_cpu() will always get correct result.
+	 */
+	WRITE_ONCE(rq->ttwu_pending, 0);
+	rq_unlock_irqrestore(rq, &rf);
+}
+
+/*
+ * Prepare the scene for sending an IPI for a remote smp_call
+ *
+ * Returns true if the caller can proceed with sending the IPI.
+ * Returns false otherwise.
+ */
+bool call_function_single_prep_ipi(int cpu)
+{
+	if (set_nr_if_polling(cpu_rq(cpu)->idle)) {
+		trace_sched_wake_idle_without_ipi(cpu);
+		return false;
+	}
+
+	return true;
+}
+
+/*
+ * Queue a task on the target CPUs wake_list and wake the CPU via IPI if
+ * necessary. The wakee CPU on receipt of the IPI will queue the task
+ * via sched_ttwu_wakeup() for activation so the wakee incurs the cost
+ * of the wakeup instead of the waker.
+ */
+static void __ttwu_queue_wakelist(struct task_struct *p, int cpu, int wake_flags)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	p->sched_remote_wakeup = !!(wake_flags & WF_MIGRATED);
+
+	WRITE_ONCE(rq->ttwu_pending, 1);
+	__smp_call_single_queue(cpu, &p->wake_entry.llist);
+}
+
+void wake_up_if_idle(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	guard(rcu)();
+	if (is_idle_task(rcu_dereference(rq->curr))) {
+		guard(rq_lock_irqsave)(rq);
+		if (is_idle_task(rq->curr))
+			resched_curr(rq);
+	}
+}
+
+bool cpus_share_cache(int this_cpu, int that_cpu)
+{
+	if (this_cpu == that_cpu)
+		return true;
+
+	return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu);
+}
+
+static inline bool ttwu_queue_cond(struct task_struct *p, int cpu)
+{
+	/*
+	 * Do not complicate things with the async wake_list while the CPU is
+	 * in hotplug state.
+	 */
+	if (!cpu_active(cpu))
+		return false;
+
+	/* Ensure the task will still be allowed to run on the CPU. */
+	if (!cpumask_test_cpu(cpu, p->cpus_ptr))
+		return false;
+
+	/*
+	 * If the CPU does not share cache, then queue the task on the
+	 * remote rqs wakelist to avoid accessing remote data.
+	 */
+	if (!cpus_share_cache(smp_processor_id(), cpu))
+		return true;
+
+	if (cpu == smp_processor_id())
+		return false;
+
+	/*
+	 * If the wakee cpu is idle, or the task is descheduling and the
+	 * only running task on the CPU, then use the wakelist to offload
+	 * the task activation to the idle (or soon-to-be-idle) CPU as
+	 * the current CPU is likely busy. nr_running is checked to
+	 * avoid unnecessary task stacking.
+	 *
+	 * Note that we can only get here with (wakee) p->on_rq=0,
+	 * p->on_cpu can be whatever, we've done the dequeue, so
+	 * the wakee has been accounted out of ->nr_running.
+	 */
+	if (!cpu_rq(cpu)->nr_running)
+		return true;
+
+	return false;
+}
+
+static bool ttwu_queue_wakelist(struct task_struct *p, int cpu, int wake_flags)
+{
+	if (sched_feat(TTWU_QUEUE) && ttwu_queue_cond(p, cpu)) {
+		sched_clock_cpu(cpu); /* Sync clocks across CPUs */
+		__ttwu_queue_wakelist(p, cpu, wake_flags);
+		return true;
+	}
+
+	return false;
+}
+
+#else /* !CONFIG_SMP */
+
+static inline bool ttwu_queue_wakelist(struct task_struct *p, int cpu, int wake_flags)
+{
+	return false;
+}
+
+#endif /* CONFIG_SMP */
+
+static void ttwu_queue(struct task_struct *p, int cpu, int wake_flags)
+{
+	struct rq *rq = cpu_rq(cpu);
+	struct rq_flags rf;
+
+	if (ttwu_queue_wakelist(p, cpu, wake_flags))
+		return;
+
+	rq_lock(rq, &rf);
+	update_rq_clock(rq);
+	ttwu_do_activate(rq, p, wake_flags, &rf);
+	rq_unlock(rq, &rf);
+}
+
+/*
+ * Invoked from try_to_wake_up() to check whether the task can be woken up.
+ *
+ * The caller holds p::pi_lock if p != current or has preemption
+ * disabled when p == current.
+ *
+ * The rules of PREEMPT_RT saved_state:
+ *
+ *   The related locking code always holds p::pi_lock when updating
+ *   p::saved_state, which means the code is fully serialized in both cases.
+ *
+ *   The lock wait and lock wakeups happen via TASK_RTLOCK_WAIT. No other
+ *   bits set. This allows to distinguish all wakeup scenarios.
+ */
+static __always_inline
+bool ttwu_state_match(struct task_struct *p, unsigned int state, int *success)
+{
+	int match;
+
+	if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)) {
+		WARN_ON_ONCE((state & TASK_RTLOCK_WAIT) &&
+			     state != TASK_RTLOCK_WAIT);
+	}
+
+	*success = !!(match = __task_state_match(p, state));
+
+#ifdef CONFIG_PREEMPT_RT
+	/*
+	 * Saved state preserves the task state across blocking on
+	 * an RT lock.  If the state matches, set p::saved_state to
+	 * TASK_RUNNING, but do not wake the task because it waits
+	 * for a lock wakeup. Also indicate success because from
+	 * the regular waker's point of view this has succeeded.
+	 *
+	 * After acquiring the lock the task will restore p::__state
+	 * from p::saved_state which ensures that the regular
+	 * wakeup is not lost. The restore will also set
+	 * p::saved_state to TASK_RUNNING so any further tests will
+	 * not result in false positives vs. @success
+	 */
+	if (match < 0)
+		p->saved_state = TASK_RUNNING;
+#endif
+	return match > 0;
+}
+
+/*
+ * Notes on Program-Order guarantees on SMP systems.
+ *
+ *  MIGRATION
+ *
+ * The basic program-order guarantee on SMP systems is that when a task [t]
+ * migrates, all its activity on its old CPU [c0] happens-before any subsequent
+ * execution on its new CPU [c1].
+ *
+ * For migration (of runnable tasks) this is provided by the following means:
+ *
+ *  A) UNLOCK of the rq(c0)->lock scheduling out task t
+ *  B) migration for t is required to synchronize *both* rq(c0)->lock and
+ *     rq(c1)->lock (if not at the same time, then in that order).
+ *  C) LOCK of the rq(c1)->lock scheduling in task
+ *
+ * Release/acquire chaining guarantees that B happens after A and C after B.
+ * Note: the CPU doing B need not be c0 or c1
+ *
+ * Example:
+ *
+ *   CPU0            CPU1            CPU2
+ *
+ *   LOCK rq(0)->lock
+ *   sched-out X
+ *   sched-in Y
+ *   UNLOCK rq(0)->lock
+ *
+ *                                   LOCK rq(0)->lock // orders against CPU0
+ *                                   dequeue X
+ *                                   UNLOCK rq(0)->lock
+ *
+ *                                   LOCK rq(1)->lock
+ *                                   enqueue X
+ *                                   UNLOCK rq(1)->lock
+ *
+ *                   LOCK rq(1)->lock // orders against CPU2
+ *                   sched-out Z
+ *                   sched-in X
+ *                   UNLOCK rq(1)->lock
+ *
+ *
+ *  BLOCKING -- aka. SLEEP + WAKEUP
+ *
+ * For blocking we (obviously) need to provide the same guarantee as for
+ * migration. However the means are completely different as there is no lock
+ * chain to provide order. Instead we do:
+ *
+ *   1) smp_store_release(X->on_cpu, 0)   -- finish_task()
+ *   2) smp_cond_load_acquire(!X->on_cpu) -- try_to_wake_up()
+ *
+ * Example:
+ *
+ *   CPU0 (schedule)  CPU1 (try_to_wake_up) CPU2 (schedule)
+ *
+ *   LOCK rq(0)->lock LOCK X->pi_lock
+ *   dequeue X
+ *   sched-out X
+ *   smp_store_release(X->on_cpu, 0);
+ *
+ *                    smp_cond_load_acquire(&X->on_cpu, !VAL);
+ *                    X->state = WAKING
+ *                    set_task_cpu(X,2)
+ *
+ *                    LOCK rq(2)->lock
+ *                    enqueue X
+ *                    X->state = RUNNING
+ *                    UNLOCK rq(2)->lock
+ *
+ *                                          LOCK rq(2)->lock // orders against CPU1
+ *                                          sched-out Z
+ *                                          sched-in X
+ *                                          UNLOCK rq(2)->lock
+ *
+ *                    UNLOCK X->pi_lock
+ *   UNLOCK rq(0)->lock
+ *
+ *
+ * However, for wakeups there is a second guarantee we must provide, namely we
+ * must ensure that CONDITION=1 done by the caller can not be reordered with
+ * accesses to the task state; see try_to_wake_up() and set_current_state().
+ */
+
+/**
+ * try_to_wake_up - wake up a thread
+ * @p: the thread to be awakened
+ * @state: the mask of task states that can be woken
+ * @wake_flags: wake modifier flags (WF_*)
+ *
+ * Conceptually does:
+ *
+ *   If (@state & @p->state) @p->state = TASK_RUNNING.
+ *
+ * If the task was not queued/runnable, also place it back on a runqueue.
+ *
+ * This function is atomic against schedule() which would dequeue the task.
+ *
+ * It issues a full memory barrier before accessing @p->state, see the comment
+ * with set_current_state().
+ *
+ * Uses p->pi_lock to serialize against concurrent wake-ups.
+ *
+ * Relies on p->pi_lock stabilizing:
+ *  - p->sched_class
+ *  - p->cpus_ptr
+ *  - p->sched_task_group
+ * in order to do migration, see its use of select_task_rq()/set_task_cpu().
+ *
+ * Tries really hard to only take one task_rq(p)->lock for performance.
+ * Takes rq->lock in:
+ *  - ttwu_runnable()    -- old rq, unavoidable, see comment there;
+ *  - ttwu_queue()       -- new rq, for enqueue of the task;
+ *  - psi_ttwu_dequeue() -- much sadness :-( accounting will kill us.
+ *
+ * As a consequence we race really badly with just about everything. See the
+ * many memory barriers and their comments for details.
+ *
+ * Return: %true if @p->state changes (an actual wakeup was done),
+ *	   %false otherwise.
+ */
+int try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
+{
+	guard(preempt)();
+	int cpu, success = 0;
+
+	if (p == current) {
+		/*
+		 * We're waking current, this means 'p->on_rq' and 'task_cpu(p)
+		 * == smp_processor_id()'. Together this means we can special
+		 * case the whole 'p->on_rq && ttwu_runnable()' case below
+		 * without taking any locks.
+		 *
+		 * In particular:
+		 *  - we rely on Program-Order guarantees for all the ordering,
+		 *  - we're serialized against set_special_state() by virtue of
+		 *    it disabling IRQs (this allows not taking ->pi_lock).
+		 */
+		if (!ttwu_state_match(p, state, &success))
+			goto out;
+
+		trace_sched_waking(p);
+		ttwu_do_wakeup(p);
+		goto out;
+	}
+
+	/*
+	 * If we are going to wake up a thread waiting for CONDITION we
+	 * need to ensure that CONDITION=1 done by the caller can not be
+	 * reordered with p->state check below. This pairs with smp_store_mb()
+	 * in set_current_state() that the waiting thread does.
+	 */
+	scoped_guard (raw_spinlock_irqsave, &p->pi_lock) {
+		smp_mb__after_spinlock();
+		if (!ttwu_state_match(p, state, &success))
+			break;
+
+		trace_sched_waking(p);
+
+		/*
+		 * Ensure we load p->on_rq _after_ p->state, otherwise it would
+		 * be possible to, falsely, observe p->on_rq == 0 and get stuck
+		 * in smp_cond_load_acquire() below.
+		 *
+		 * sched_ttwu_pending()			try_to_wake_up()
+		 *   STORE p->on_rq = 1			  LOAD p->state
+		 *   UNLOCK rq->lock
+		 *
+		 * __schedule() (switch to task 'p')
+		 *   LOCK rq->lock			  smp_rmb();
+		 *   smp_mb__after_spinlock();
+		 *   UNLOCK rq->lock
+		 *
+		 * [task p]
+		 *   STORE p->state = UNINTERRUPTIBLE	  LOAD p->on_rq
+		 *
+		 * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in
+		 * __schedule().  See the comment for smp_mb__after_spinlock().
+		 *
+		 * A similar smb_rmb() lives in try_invoke_on_locked_down_task().
+		 */
+		smp_rmb();
+		if (READ_ONCE(p->on_rq) && ttwu_runnable(p, wake_flags))
+			break;
+
+#ifdef CONFIG_SMP
+		/*
+		 * Ensure we load p->on_cpu _after_ p->on_rq, otherwise it would be
+		 * possible to, falsely, observe p->on_cpu == 0.
+		 *
+		 * One must be running (->on_cpu == 1) in order to remove oneself
+		 * from the runqueue.
+		 *
+		 * __schedule() (switch to task 'p')	try_to_wake_up()
+		 *   STORE p->on_cpu = 1		  LOAD p->on_rq
+		 *   UNLOCK rq->lock
+		 *
+		 * __schedule() (put 'p' to sleep)
+		 *   LOCK rq->lock			  smp_rmb();
+		 *   smp_mb__after_spinlock();
+		 *   STORE p->on_rq = 0			  LOAD p->on_cpu
+		 *
+		 * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in
+		 * __schedule().  See the comment for smp_mb__after_spinlock().
+		 *
+		 * Form a control-dep-acquire with p->on_rq == 0 above, to ensure
+		 * schedule()'s deactivate_task() has 'happened' and p will no longer
+		 * care about it's own p->state. See the comment in __schedule().
+		 */
+		smp_acquire__after_ctrl_dep();
+
+		/*
+		 * We're doing the wakeup (@success == 1), they did a dequeue (p->on_rq
+		 * == 0), which means we need to do an enqueue, change p->state to
+		 * TASK_WAKING such that we can unlock p->pi_lock before doing the
+		 * enqueue, such as ttwu_queue_wakelist().
+		 */
+		WRITE_ONCE(p->__state, TASK_WAKING);
+
+		/*
+		 * If the owning (remote) CPU is still in the middle of schedule() with
+		 * this task as prev, considering queueing p on the remote CPUs wake_list
+		 * which potentially sends an IPI instead of spinning on p->on_cpu to
+		 * let the waker make forward progress. This is safe because IRQs are
+		 * disabled and the IPI will deliver after on_cpu is cleared.
+		 *
+		 * Ensure we load task_cpu(p) after p->on_cpu:
+		 *
+		 * set_task_cpu(p, cpu);
+		 *   STORE p->cpu = @cpu
+		 * __schedule() (switch to task 'p')
+		 *   LOCK rq->lock
+		 *   smp_mb__after_spin_lock()		smp_cond_load_acquire(&p->on_cpu)
+		 *   STORE p->on_cpu = 1		LOAD p->cpu
+		 *
+		 * to ensure we observe the correct CPU on which the task is currently
+		 * scheduling.
+		 */
+		if (smp_load_acquire(&p->on_cpu) &&
+		    ttwu_queue_wakelist(p, task_cpu(p), wake_flags))
+			break;
+
+		/*
+		 * If the owning (remote) CPU is still in the middle of schedule() with
+		 * this task as prev, wait until it's done referencing the task.
+		 *
+		 * Pairs with the smp_store_release() in finish_task().
+		 *
+		 * This ensures that tasks getting woken will be fully ordered against
+		 * their previous state and preserve Program Order.
+		 */
+		smp_cond_load_acquire(&p->on_cpu, !VAL);
+
+		cpu = select_task_rq(p, p->wake_cpu, wake_flags | WF_TTWU);
+		if (task_cpu(p) != cpu) {
+			if (p->in_iowait) {
+				delayacct_blkio_end(p);
+				atomic_dec(&task_rq(p)->nr_iowait);
+			}
+
+			wake_flags |= WF_MIGRATED;
+			psi_ttwu_dequeue(p);
+			set_task_cpu(p, cpu);
+		}
+#else
+		cpu = task_cpu(p);
+#endif /* CONFIG_SMP */
+
+		ttwu_queue(p, cpu, wake_flags);
+	}
+out:
+	if (success)
+		ttwu_stat(p, task_cpu(p), wake_flags);
+
+	return success;
+}
+
+static bool __task_needs_rq_lock(struct task_struct *p)
+{
+	unsigned int state = READ_ONCE(p->__state);
+
+	/*
+	 * Since pi->lock blocks try_to_wake_up(), we don't need rq->lock when
+	 * the task is blocked. Make sure to check @state since ttwu() can drop
+	 * locks at the end, see ttwu_queue_wakelist().
+	 */
+	if (state == TASK_RUNNING || state == TASK_WAKING)
+		return true;
+
+	/*
+	 * Ensure we load p->on_rq after p->__state, otherwise it would be
+	 * possible to, falsely, observe p->on_rq == 0.
+	 *
+	 * See try_to_wake_up() for a longer comment.
+	 */
+	smp_rmb();
+	if (p->on_rq)
+		return true;
+
+#ifdef CONFIG_SMP
+	/*
+	 * Ensure the task has finished __schedule() and will not be referenced
+	 * anymore. Again, see try_to_wake_up() for a longer comment.
+	 */
+	smp_rmb();
+	smp_cond_load_acquire(&p->on_cpu, !VAL);
+#endif
+
+	return false;
+}
+
+/**
+ * task_call_func - Invoke a function on task in fixed state
+ * @p: Process for which the function is to be invoked, can be @current.
+ * @func: Function to invoke.
+ * @arg: Argument to function.
+ *
+ * Fix the task in it's current state by avoiding wakeups and or rq operations
+ * and call @func(@arg) on it.  This function can use ->on_rq and task_curr()
+ * to work out what the state is, if required.  Given that @func can be invoked
+ * with a runqueue lock held, it had better be quite lightweight.
+ *
+ * Returns:
+ *   Whatever @func returns
+ */
+int task_call_func(struct task_struct *p, task_call_f func, void *arg)
+{
+	struct rq *rq = NULL;
+	struct rq_flags rf;
+	int ret;
+
+	raw_spin_lock_irqsave(&p->pi_lock, rf.flags);
+
+	if (__task_needs_rq_lock(p))
+		rq = __task_rq_lock(p, &rf);
+
+	/*
+	 * At this point the task is pinned; either:
+	 *  - blocked and we're holding off wakeups	 (pi->lock)
+	 *  - woken, and we're holding off enqueue	 (rq->lock)
+	 *  - queued, and we're holding off schedule	 (rq->lock)
+	 *  - running, and we're holding off de-schedule (rq->lock)
+	 *
+	 * The called function (@func) can use: task_curr(), p->on_rq and
+	 * p->__state to differentiate between these states.
+	 */
+	ret = func(p, arg);
+
+	if (rq)
+		rq_unlock(rq, &rf);
+
+	raw_spin_unlock_irqrestore(&p->pi_lock, rf.flags);
+	return ret;
+}
+
+/**
+ * cpu_curr_snapshot - Return a snapshot of the currently running task
+ * @cpu: The CPU on which to snapshot the task.
+ *
+ * Returns the task_struct pointer of the task "currently" running on
+ * the specified CPU.  If the same task is running on that CPU throughout,
+ * the return value will be a pointer to that task's task_struct structure.
+ * If the CPU did any context switches even vaguely concurrently with the
+ * execution of this function, the return value will be a pointer to the
+ * task_struct structure of a randomly chosen task that was running on
+ * that CPU somewhere around the time that this function was executing.
+ *
+ * If the specified CPU was offline, the return value is whatever it
+ * is, perhaps a pointer to the task_struct structure of that CPU's idle
+ * task, but there is no guarantee.  Callers wishing a useful return
+ * value must take some action to ensure that the specified CPU remains
+ * online throughout.
+ *
+ * This function executes full memory barriers before and after fetching
+ * the pointer, which permits the caller to confine this function's fetch
+ * with respect to the caller's accesses to other shared variables.
+ */
+struct task_struct *cpu_curr_snapshot(int cpu)
+{
+	struct task_struct *t;
+
+	smp_mb(); /* Pairing determined by caller's synchronization design. */
+	t = rcu_dereference(cpu_curr(cpu));
+	smp_mb(); /* Pairing determined by caller's synchronization design. */
+	return t;
+}
+
+/**
+ * wake_up_process - Wake up a specific process
+ * @p: The process to be woken up.
+ *
+ * Attempt to wake up the nominated process and move it to the set of runnable
+ * processes.
+ *
+ * Return: 1 if the process was woken up, 0 if it was already running.
+ *
+ * This function executes a full memory barrier before accessing the task state.
+ */
+int wake_up_process(struct task_struct *p)
+{
+	return try_to_wake_up(p, TASK_NORMAL, 0);
+}
+EXPORT_SYMBOL(wake_up_process);
+
+int wake_up_state(struct task_struct *p, unsigned int state)
+{
+	return try_to_wake_up(p, state, 0);
+}
+
+/*
+ * Perform scheduler related setup for a newly forked process p.
+ * p is forked by current.
+ *
+ * __sched_fork() is basic setup used by init_idle() too:
+ */
+static void __sched_fork(unsigned long clone_flags, struct task_struct *p)
+{
+	p->on_rq			= 0;
+
+	p->se.on_rq			= 0;
+	p->se.exec_start		= 0;
+	p->se.sum_exec_runtime		= 0;
+	p->se.prev_sum_exec_runtime	= 0;
+	p->se.nr_migrations		= 0;
+	p->se.vruntime			= 0;
+	p->se.vlag			= 0;
+	p->se.slice			= sysctl_sched_base_slice;
+	INIT_LIST_HEAD(&p->se.group_node);
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	p->se.cfs_rq			= NULL;
+#endif
+
+#ifdef CONFIG_SCHEDSTATS
+	/* Even if schedstat is disabled, there should not be garbage */
+	memset(&p->stats, 0, sizeof(p->stats));
+#endif
+
+	RB_CLEAR_NODE(&p->dl.rb_node);
+	init_dl_task_timer(&p->dl);
+	init_dl_inactive_task_timer(&p->dl);
+	__dl_clear_params(p);
+
+	INIT_LIST_HEAD(&p->rt.run_list);
+	p->rt.timeout		= 0;
+	p->rt.time_slice	= sched_rr_timeslice;
+	p->rt.on_rq		= 0;
+	p->rt.on_list		= 0;
+
+#ifdef CONFIG_PREEMPT_NOTIFIERS
+	INIT_HLIST_HEAD(&p->preempt_notifiers);
+#endif
+
+#ifdef CONFIG_COMPACTION
+	p->capture_control = NULL;
+#endif
+	init_numa_balancing(clone_flags, p);
+#ifdef CONFIG_SMP
+	p->wake_entry.u_flags = CSD_TYPE_TTWU;
+	p->migration_pending = NULL;
+#endif
+	init_sched_mm_cid(p);
+}
+
+DEFINE_STATIC_KEY_FALSE(sched_numa_balancing);
+
+#ifdef CONFIG_NUMA_BALANCING
+
+int sysctl_numa_balancing_mode;
+
+static void __set_numabalancing_state(bool enabled)
+{
+	if (enabled)
+		static_branch_enable(&sched_numa_balancing);
+	else
+		static_branch_disable(&sched_numa_balancing);
+}
+
+void set_numabalancing_state(bool enabled)
+{
+	if (enabled)
+		sysctl_numa_balancing_mode = NUMA_BALANCING_NORMAL;
+	else
+		sysctl_numa_balancing_mode = NUMA_BALANCING_DISABLED;
+	__set_numabalancing_state(enabled);
+}
+
+#ifdef CONFIG_PROC_SYSCTL
+static void reset_memory_tiering(void)
+{
+	struct pglist_data *pgdat;
+
+	for_each_online_pgdat(pgdat) {
+		pgdat->nbp_threshold = 0;
+		pgdat->nbp_th_nr_cand = node_page_state(pgdat, PGPROMOTE_CANDIDATE);
+		pgdat->nbp_th_start = jiffies_to_msecs(jiffies);
+	}
+}
+
+static int sysctl_numa_balancing(struct ctl_table *table, int write,
+			  void *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct ctl_table t;
+	int err;
+	int state = sysctl_numa_balancing_mode;
+
+	if (write && !capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	t = *table;
+	t.data = &state;
+	err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
+	if (err < 0)
+		return err;
+	if (write) {
+		if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) &&
+		    (state & NUMA_BALANCING_MEMORY_TIERING))
+			reset_memory_tiering();
+		sysctl_numa_balancing_mode = state;
+		__set_numabalancing_state(state);
+	}
+	return err;
+}
+#endif
+#endif
+
+#ifdef CONFIG_SCHEDSTATS
+
+DEFINE_STATIC_KEY_FALSE(sched_schedstats);
+
+static void set_schedstats(bool enabled)
+{
+	if (enabled)
+		static_branch_enable(&sched_schedstats);
+	else
+		static_branch_disable(&sched_schedstats);
+}
+
+void force_schedstat_enabled(void)
+{
+	if (!schedstat_enabled()) {
+		pr_info("kernel profiling enabled schedstats, disable via kernel.sched_schedstats.\n");
+		static_branch_enable(&sched_schedstats);
+	}
+}
+
+static int __init setup_schedstats(char *str)
+{
+	int ret = 0;
+	if (!str)
+		goto out;
+
+	if (!strcmp(str, "enable")) {
+		set_schedstats(true);
+		ret = 1;
+	} else if (!strcmp(str, "disable")) {
+		set_schedstats(false);
+		ret = 1;
+	}
+out:
+	if (!ret)
+		pr_warn("Unable to parse schedstats=\n");
+
+	return ret;
+}
+__setup("schedstats=", setup_schedstats);
+
+#ifdef CONFIG_PROC_SYSCTL
+static int sysctl_schedstats(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
+{
+	struct ctl_table t;
+	int err;
+	int state = static_branch_likely(&sched_schedstats);
+
+	if (write && !capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	t = *table;
+	t.data = &state;
+	err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
+	if (err < 0)
+		return err;
+	if (write)
+		set_schedstats(state);
+	return err;
+}
+#endif /* CONFIG_PROC_SYSCTL */
+#endif /* CONFIG_SCHEDSTATS */
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table sched_core_sysctls[] = {
+#ifdef CONFIG_SCHEDSTATS
+	{
+		.procname       = "sched_schedstats",
+		.data           = NULL,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = sysctl_schedstats,
+		.extra1         = SYSCTL_ZERO,
+		.extra2         = SYSCTL_ONE,
+	},
+#endif /* CONFIG_SCHEDSTATS */
+#ifdef CONFIG_UCLAMP_TASK
+	{
+		.procname       = "sched_util_clamp_min",
+		.data           = &sysctl_sched_uclamp_util_min,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = sysctl_sched_uclamp_handler,
+	},
+	{
+		.procname       = "sched_util_clamp_max",
+		.data           = &sysctl_sched_uclamp_util_max,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = sysctl_sched_uclamp_handler,
+	},
+	{
+		.procname       = "sched_util_clamp_min_rt_default",
+		.data           = &sysctl_sched_uclamp_util_min_rt_default,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = sysctl_sched_uclamp_handler,
+	},
+#endif /* CONFIG_UCLAMP_TASK */
+#ifdef CONFIG_NUMA_BALANCING
+	{
+		.procname	= "numa_balancing",
+		.data		= NULL, /* filled in by handler */
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= sysctl_numa_balancing,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_FOUR,
+	},
+#endif /* CONFIG_NUMA_BALANCING */
+	{}
+};
+static int __init sched_core_sysctl_init(void)
+{
+	register_sysctl_init("kernel", sched_core_sysctls);
+	return 0;
+}
+late_initcall(sched_core_sysctl_init);
+#endif /* CONFIG_SYSCTL */
+
+/*
+ * fork()/clone()-time setup:
+ */
+int sched_fork(unsigned long clone_flags, struct task_struct *p)
+{
+	__sched_fork(clone_flags, p);
+	/*
+	 * We mark the process as NEW here. This guarantees that
+	 * nobody will actually run it, and a signal or other external
+	 * event cannot wake it up and insert it on the runqueue either.
+	 */
+	p->__state = TASK_NEW;
+
+	/*
+	 * Make sure we do not leak PI boosting priority to the child.
+	 */
+	p->prio = current->normal_prio;
+
+	uclamp_fork(p);
+
+	/*
+	 * Revert to default priority/policy on fork if requested.
+	 */
+	if (unlikely(p->sched_reset_on_fork)) {
+		if (task_has_dl_policy(p) || task_has_rt_policy(p)) {
+			p->policy = SCHED_NORMAL;
+			p->static_prio = NICE_TO_PRIO(0);
+			p->rt_priority = 0;
+		} else if (PRIO_TO_NICE(p->static_prio) < 0)
+			p->static_prio = NICE_TO_PRIO(0);
+
+		p->prio = p->normal_prio = p->static_prio;
+		set_load_weight(p, false);
+
+		/*
+		 * We don't need the reset flag anymore after the fork. It has
+		 * fulfilled its duty:
+		 */
+		p->sched_reset_on_fork = 0;
+	}
+
+	if (dl_prio(p->prio))
+		return -EAGAIN;
+	else if (rt_prio(p->prio))
+		p->sched_class = &rt_sched_class;
+	else
+		p->sched_class = &fair_sched_class;
+
+	init_entity_runnable_average(&p->se);
+
+
+#ifdef CONFIG_SCHED_INFO
+	if (likely(sched_info_on()))
+		memset(&p->sched_info, 0, sizeof(p->sched_info));
+#endif
+#if defined(CONFIG_SMP)
+	p->on_cpu = 0;
+#endif
+	init_task_preempt_count(p);
+#ifdef CONFIG_SMP
+	plist_node_init(&p->pushable_tasks, MAX_PRIO);
+	RB_CLEAR_NODE(&p->pushable_dl_tasks);
+#endif
+	return 0;
+}
+
+void sched_cgroup_fork(struct task_struct *p, struct kernel_clone_args *kargs)
+{
+	unsigned long flags;
+
+	/*
+	 * Because we're not yet on the pid-hash, p->pi_lock isn't strictly
+	 * required yet, but lockdep gets upset if rules are violated.
+	 */
+	raw_spin_lock_irqsave(&p->pi_lock, flags);
+#ifdef CONFIG_CGROUP_SCHED
+	if (1) {
+		struct task_group *tg;
+		tg = container_of(kargs->cset->subsys[cpu_cgrp_id],
+				  struct task_group, css);
+		tg = autogroup_task_group(p, tg);
+		p->sched_task_group = tg;
+	}
+#endif
+	rseq_migrate(p);
+	/*
+	 * We're setting the CPU for the first time, we don't migrate,
+	 * so use __set_task_cpu().
+	 */
+	__set_task_cpu(p, smp_processor_id());
+	if (p->sched_class->task_fork)
+		p->sched_class->task_fork(p);
+	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+}
+
+void sched_post_fork(struct task_struct *p)
+{
+	uclamp_post_fork(p);
+}
+
+unsigned long to_ratio(u64 period, u64 runtime)
+{
+	if (runtime == RUNTIME_INF)
+		return BW_UNIT;
+
+	/*
+	 * Doing this here saves a lot of checks in all
+	 * the calling paths, and returning zero seems
+	 * safe for them anyway.
+	 */
+	if (period == 0)
+		return 0;
+
+	return div64_u64(runtime << BW_SHIFT, period);
+}
+
+/*
+ * wake_up_new_task - wake up a newly created task for the first time.
+ *
+ * This function will do some initial scheduler statistics housekeeping
+ * that must be done for every newly created context, then puts the task
+ * on the runqueue and wakes it.
+ */
+void wake_up_new_task(struct task_struct *p)
+{
+	struct rq_flags rf;
+	struct rq *rq;
+
+	raw_spin_lock_irqsave(&p->pi_lock, rf.flags);
+	WRITE_ONCE(p->__state, TASK_RUNNING);
+#ifdef CONFIG_SMP
+	/*
+	 * Fork balancing, do it here and not earlier because:
+	 *  - cpus_ptr can change in the fork path
+	 *  - any previously selected CPU might disappear through hotplug
+	 *
+	 * Use __set_task_cpu() to avoid calling sched_class::migrate_task_rq,
+	 * as we're not fully set-up yet.
+	 */
+	p->recent_used_cpu = task_cpu(p);
+	rseq_migrate(p);
+	__set_task_cpu(p, select_task_rq(p, task_cpu(p), WF_FORK));
+#endif
+	rq = __task_rq_lock(p, &rf);
+	update_rq_clock(rq);
+	post_init_entity_util_avg(p);
+
+	activate_task(rq, p, ENQUEUE_NOCLOCK);
+	trace_sched_wakeup_new(p);
+	check_preempt_curr(rq, p, WF_FORK);
+#ifdef CONFIG_SMP
+	if (p->sched_class->task_woken) {
+		/*
+		 * Nothing relies on rq->lock after this, so it's fine to
+		 * drop it.
+		 */
+		rq_unpin_lock(rq, &rf);
+		p->sched_class->task_woken(rq, p);
+		rq_repin_lock(rq, &rf);
+	}
+#endif
+	task_rq_unlock(rq, p, &rf);
+}
+
+#ifdef CONFIG_PREEMPT_NOTIFIERS
+
+static DEFINE_STATIC_KEY_FALSE(preempt_notifier_key);
+
+void preempt_notifier_inc(void)
+{
+	static_branch_inc(&preempt_notifier_key);
+}
+EXPORT_SYMBOL_GPL(preempt_notifier_inc);
+
+void preempt_notifier_dec(void)
+{
+	static_branch_dec(&preempt_notifier_key);
+}
+EXPORT_SYMBOL_GPL(preempt_notifier_dec);
+
+/**
+ * preempt_notifier_register - tell me when current is being preempted & rescheduled
+ * @notifier: notifier struct to register
+ */
+void preempt_notifier_register(struct preempt_notifier *notifier)
+{
+	if (!static_branch_unlikely(&preempt_notifier_key))
+		WARN(1, "registering preempt_notifier while notifiers disabled\n");
+
+	hlist_add_head(&notifier->link, &current->preempt_notifiers);
+}
+EXPORT_SYMBOL_GPL(preempt_notifier_register);
+
+/**
+ * preempt_notifier_unregister - no longer interested in preemption notifications
+ * @notifier: notifier struct to unregister
+ *
+ * This is *not* safe to call from within a preemption notifier.
+ */
+void preempt_notifier_unregister(struct preempt_notifier *notifier)
+{
+	hlist_del(&notifier->link);
+}
+EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
+
+static void __fire_sched_in_preempt_notifiers(struct task_struct *curr)
+{
+	struct preempt_notifier *notifier;
+
+	hlist_for_each_entry(notifier, &curr->preempt_notifiers, link)
+		notifier->ops->sched_in(notifier, raw_smp_processor_id());
+}
+
+static __always_inline void fire_sched_in_preempt_notifiers(struct task_struct *curr)
+{
+	if (static_branch_unlikely(&preempt_notifier_key))
+		__fire_sched_in_preempt_notifiers(curr);
+}
+
+static void
+__fire_sched_out_preempt_notifiers(struct task_struct *curr,
+				   struct task_struct *next)
+{
+	struct preempt_notifier *notifier;
+
+	hlist_for_each_entry(notifier, &curr->preempt_notifiers, link)
+		notifier->ops->sched_out(notifier, next);
+}
+
+static __always_inline void
+fire_sched_out_preempt_notifiers(struct task_struct *curr,
+				 struct task_struct *next)
+{
+	if (static_branch_unlikely(&preempt_notifier_key))
+		__fire_sched_out_preempt_notifiers(curr, next);
+}
+
+#else /* !CONFIG_PREEMPT_NOTIFIERS */
+
+static inline void fire_sched_in_preempt_notifiers(struct task_struct *curr)
+{
+}
+
+static inline void
+fire_sched_out_preempt_notifiers(struct task_struct *curr,
+				 struct task_struct *next)
+{
+}
+
+#endif /* CONFIG_PREEMPT_NOTIFIERS */
+
+static inline void prepare_task(struct task_struct *next)
+{
+#ifdef CONFIG_SMP
+	/*
+	 * Claim the task as running, we do this before switching to it
+	 * such that any running task will have this set.
+	 *
+	 * See the smp_load_acquire(&p->on_cpu) case in ttwu() and
+	 * its ordering comment.
+	 */
+	WRITE_ONCE(next->on_cpu, 1);
+#endif
+}
+
+static inline void finish_task(struct task_struct *prev)
+{
+#ifdef CONFIG_SMP
+	/*
+	 * This must be the very last reference to @prev from this CPU. After
+	 * p->on_cpu is cleared, the task can be moved to a different CPU. We
+	 * must ensure this doesn't happen until the switch is completely
+	 * finished.
+	 *
+	 * In particular, the load of prev->state in finish_task_switch() must
+	 * happen before this.
+	 *
+	 * Pairs with the smp_cond_load_acquire() in try_to_wake_up().
+	 */
+	smp_store_release(&prev->on_cpu, 0);
+#endif
+}
+
+#ifdef CONFIG_SMP
+
+static void do_balance_callbacks(struct rq *rq, struct balance_callback *head)
+{
+	void (*func)(struct rq *rq);
+	struct balance_callback *next;
+
+	lockdep_assert_rq_held(rq);
+
+	while (head) {
+		func = (void (*)(struct rq *))head->func;
+		next = head->next;
+		head->next = NULL;
+		head = next;
+
+		func(rq);
+	}
+}
+
+static void balance_push(struct rq *rq);
+
+/*
+ * balance_push_callback is a right abuse of the callback interface and plays
+ * by significantly different rules.
+ *
+ * Where the normal balance_callback's purpose is to be ran in the same context
+ * that queued it (only later, when it's safe to drop rq->lock again),
+ * balance_push_callback is specifically targeted at __schedule().
+ *
+ * This abuse is tolerated because it places all the unlikely/odd cases behind
+ * a single test, namely: rq->balance_callback == NULL.
+ */
+struct balance_callback balance_push_callback = {
+	.next = NULL,
+	.func = balance_push,
+};
+
+static inline struct balance_callback *
+__splice_balance_callbacks(struct rq *rq, bool split)
+{
+	struct balance_callback *head = rq->balance_callback;
+
+	if (likely(!head))
+		return NULL;
+
+	lockdep_assert_rq_held(rq);
+	/*
+	 * Must not take balance_push_callback off the list when
+	 * splice_balance_callbacks() and balance_callbacks() are not
+	 * in the same rq->lock section.
+	 *
+	 * In that case it would be possible for __schedule() to interleave
+	 * and observe the list empty.
+	 */
+	if (split && head == &balance_push_callback)
+		head = NULL;
+	else
+		rq->balance_callback = NULL;
+
+	return head;
+}
+
+static inline struct balance_callback *splice_balance_callbacks(struct rq *rq)
+{
+	return __splice_balance_callbacks(rq, true);
+}
+
+static void __balance_callbacks(struct rq *rq)
+{
+	do_balance_callbacks(rq, __splice_balance_callbacks(rq, false));
+}
+
+static inline void balance_callbacks(struct rq *rq, struct balance_callback *head)
+{
+	unsigned long flags;
+
+	if (unlikely(head)) {
+		raw_spin_rq_lock_irqsave(rq, flags);
+		do_balance_callbacks(rq, head);
+		raw_spin_rq_unlock_irqrestore(rq, flags);
+	}
+}
+
+#else
+
+static inline void __balance_callbacks(struct rq *rq)
+{
+}
+
+static inline struct balance_callback *splice_balance_callbacks(struct rq *rq)
+{
+	return NULL;
+}
+
+static inline void balance_callbacks(struct rq *rq, struct balance_callback *head)
+{
+}
+
+#endif
+
+static inline void
+prepare_lock_switch(struct rq *rq, struct task_struct *next, struct rq_flags *rf)
+{
+	/*
+	 * Since the runqueue lock will be released by the next
+	 * task (which is an invalid locking op but in the case
+	 * of the scheduler it's an obvious special-case), so we
+	 * do an early lockdep release here:
+	 */
+	rq_unpin_lock(rq, rf);
+	spin_release(&__rq_lockp(rq)->dep_map, _THIS_IP_);
+#ifdef CONFIG_DEBUG_SPINLOCK
+	/* this is a valid case when another task releases the spinlock */
+	rq_lockp(rq)->owner = next;
+#endif
+}
+
+static inline void finish_lock_switch(struct rq *rq)
+{
+	/*
+	 * If we are tracking spinlock dependencies then we have to
+	 * fix up the runqueue lock - which gets 'carried over' from
+	 * prev into current:
+	 */
+	spin_acquire(&__rq_lockp(rq)->dep_map, 0, 0, _THIS_IP_);
+	__balance_callbacks(rq);
+	raw_spin_rq_unlock_irq(rq);
+}
+
+/*
+ * NOP if the arch has not defined these:
+ */
+
+#ifndef prepare_arch_switch
+# define prepare_arch_switch(next)	do { } while (0)
+#endif
+
+#ifndef finish_arch_post_lock_switch
+# define finish_arch_post_lock_switch()	do { } while (0)
+#endif
+
+static inline void kmap_local_sched_out(void)
+{
+#ifdef CONFIG_KMAP_LOCAL
+	if (unlikely(current->kmap_ctrl.idx))
+		__kmap_local_sched_out();
+#endif
+}
+
+static inline void kmap_local_sched_in(void)
+{
+#ifdef CONFIG_KMAP_LOCAL
+	if (unlikely(current->kmap_ctrl.idx))
+		__kmap_local_sched_in();
+#endif
+}
+
+/**
+ * prepare_task_switch - prepare to switch tasks
+ * @rq: the runqueue preparing to switch
+ * @prev: the current task that is being switched out
+ * @next: the task we are going to switch to.
+ *
+ * This is called with the rq lock held and interrupts off. It must
+ * be paired with a subsequent finish_task_switch after the context
+ * switch.
+ *
+ * prepare_task_switch sets up locking and calls architecture specific
+ * hooks.
+ */
+static inline void
+prepare_task_switch(struct rq *rq, struct task_struct *prev,
+		    struct task_struct *next)
+{
+	kcov_prepare_switch(prev);
+	sched_info_switch(rq, prev, next);
+	perf_event_task_sched_out(prev, next);
+	rseq_preempt(prev);
+	fire_sched_out_preempt_notifiers(prev, next);
+	kmap_local_sched_out();
+	prepare_task(next);
+	prepare_arch_switch(next);
+}
+
+/**
+ * finish_task_switch - clean up after a task-switch
+ * @prev: the thread we just switched away from.
+ *
+ * finish_task_switch must be called after the context switch, paired
+ * with a prepare_task_switch call before the context switch.
+ * finish_task_switch will reconcile locking set up by prepare_task_switch,
+ * and do any other architecture-specific cleanup actions.
+ *
+ * Note that we may have delayed dropping an mm in context_switch(). If
+ * so, we finish that here outside of the runqueue lock. (Doing it
+ * with the lock held can cause deadlocks; see schedule() for
+ * details.)
+ *
+ * The context switch have flipped the stack from under us and restored the
+ * local variables which were saved when this task called schedule() in the
+ * past. prev == current is still correct but we need to recalculate this_rq
+ * because prev may have moved to another CPU.
+ */
+static struct rq *finish_task_switch(struct task_struct *prev)
+	__releases(rq->lock)
+{
+	struct rq *rq = this_rq();
+	struct mm_struct *mm = rq->prev_mm;
+	unsigned int prev_state;
+
+	/*
+	 * The previous task will have left us with a preempt_count of 2
+	 * because it left us after:
+	 *
+	 *	schedule()
+	 *	  preempt_disable();			// 1
+	 *	  __schedule()
+	 *	    raw_spin_lock_irq(&rq->lock)	// 2
+	 *
+	 * Also, see FORK_PREEMPT_COUNT.
+	 */
+	if (WARN_ONCE(preempt_count() != 2*PREEMPT_DISABLE_OFFSET,
+		      "corrupted preempt_count: %s/%d/0x%x\n",
+		      current->comm, current->pid, preempt_count()))
+		preempt_count_set(FORK_PREEMPT_COUNT);
+
+	rq->prev_mm = NULL;
+
+	/*
+	 * A task struct has one reference for the use as "current".
+	 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
+	 * schedule one last time. The schedule call will never return, and
+	 * the scheduled task must drop that reference.
+	 *
+	 * We must observe prev->state before clearing prev->on_cpu (in
+	 * finish_task), otherwise a concurrent wakeup can get prev
+	 * running on another CPU and we could rave with its RUNNING -> DEAD
+	 * transition, resulting in a double drop.
+	 */
+	prev_state = READ_ONCE(prev->__state);
+	vtime_task_switch(prev);
+	perf_event_task_sched_in(prev, current);
+	finish_task(prev);
+	tick_nohz_task_switch();
+	finish_lock_switch(rq);
+	finish_arch_post_lock_switch();
+	kcov_finish_switch(current);
+	/*
+	 * kmap_local_sched_out() is invoked with rq::lock held and
+	 * interrupts disabled. There is no requirement for that, but the
+	 * sched out code does not have an interrupt enabled section.
+	 * Restoring the maps on sched in does not require interrupts being
+	 * disabled either.
+	 */
+	kmap_local_sched_in();
+
+	fire_sched_in_preempt_notifiers(current);
+	/*
+	 * When switching through a kernel thread, the loop in
+	 * membarrier_{private,global}_expedited() may have observed that
+	 * kernel thread and not issued an IPI. It is therefore possible to
+	 * schedule between user->kernel->user threads without passing though
+	 * switch_mm(). Membarrier requires a barrier after storing to
+	 * rq->curr, before returning to userspace, so provide them here:
+	 *
+	 * - a full memory barrier for {PRIVATE,GLOBAL}_EXPEDITED, implicitly
+	 *   provided by mmdrop_lazy_tlb(),
+	 * - a sync_core for SYNC_CORE.
+	 */
+	if (mm) {
+		membarrier_mm_sync_core_before_usermode(mm);
+		mmdrop_lazy_tlb_sched(mm);
+	}
+
+	if (unlikely(prev_state == TASK_DEAD)) {
+		if (prev->sched_class->task_dead)
+			prev->sched_class->task_dead(prev);
+
+		/* Task is done with its stack. */
+		put_task_stack(prev);
+
+		put_task_struct_rcu_user(prev);
+	}
+
+	return rq;
+}
+
+/**
+ * schedule_tail - first thing a freshly forked thread must call.
+ * @prev: the thread we just switched away from.
+ */
+asmlinkage __visible void schedule_tail(struct task_struct *prev)
+	__releases(rq->lock)
+{
+	/*
+	 * New tasks start with FORK_PREEMPT_COUNT, see there and
+	 * finish_task_switch() for details.
+	 *
+	 * finish_task_switch() will drop rq->lock() and lower preempt_count
+	 * and the preempt_enable() will end up enabling preemption (on
+	 * PREEMPT_COUNT kernels).
+	 */
+
+	finish_task_switch(prev);
+	preempt_enable();
+
+	if (current->set_child_tid)
+		put_user(task_pid_vnr(current), current->set_child_tid);
+
+	calculate_sigpending();
+}
+
+/*
+ * context_switch - switch to the new MM and the new thread's register state.
+ */
+static __always_inline struct rq *
+context_switch(struct rq *rq, struct task_struct *prev,
+	       struct task_struct *next, struct rq_flags *rf)
+{
+	prepare_task_switch(rq, prev, next);
+
+	/*
+	 * For paravirt, this is coupled with an exit in switch_to to
+	 * combine the page table reload and the switch backend into
+	 * one hypercall.
+	 */
+	arch_start_context_switch(prev);
+
+	/*
+	 * kernel -> kernel   lazy + transfer active
+	 *   user -> kernel   lazy + mmgrab_lazy_tlb() active
+	 *
+	 * kernel ->   user   switch + mmdrop_lazy_tlb() active
+	 *   user ->   user   switch
+	 *
+	 * switch_mm_cid() needs to be updated if the barriers provided
+	 * by context_switch() are modified.
+	 */
+	if (!next->mm) {                                // to kernel
+		enter_lazy_tlb(prev->active_mm, next);
+
+		next->active_mm = prev->active_mm;
+		if (prev->mm)                           // from user
+			mmgrab_lazy_tlb(prev->active_mm);
+		else
+			prev->active_mm = NULL;
+	} else {                                        // to user
+		membarrier_switch_mm(rq, prev->active_mm, next->mm);
+		/*
+		 * sys_membarrier() requires an smp_mb() between setting
+		 * rq->curr / membarrier_switch_mm() and returning to userspace.
+		 *
+		 * The below provides this either through switch_mm(), or in
+		 * case 'prev->active_mm == next->mm' through
+		 * finish_task_switch()'s mmdrop().
+		 */
+		switch_mm_irqs_off(prev->active_mm, next->mm, next);
+		lru_gen_use_mm(next->mm);
+
+		if (!prev->mm) {                        // from kernel
+			/* will mmdrop_lazy_tlb() in finish_task_switch(). */
+			rq->prev_mm = prev->active_mm;
+			prev->active_mm = NULL;
+		}
+	}
+
+	/* switch_mm_cid() requires the memory barriers above. */
+	switch_mm_cid(rq, prev, next);
+
+	prepare_lock_switch(rq, next, rf);
+
+	/* Here we just switch the register state and the stack. */
+	switch_to(prev, next, prev);
+	barrier();
+
+	return finish_task_switch(prev);
+}
+
+/*
+ * nr_running and nr_context_switches:
+ *
+ * externally visible scheduler statistics: current number of runnable
+ * threads, total number of context switches performed since bootup.
+ */
+unsigned int nr_running(void)
+{
+	unsigned int i, sum = 0;
+
+	for_each_online_cpu(i)
+		sum += cpu_rq(i)->nr_running;
+
+	return sum;
+}
+
+/*
+ * Check if only the current task is running on the CPU.
+ *
+ * Caution: this function does not check that the caller has disabled
+ * preemption, thus the result might have a time-of-check-to-time-of-use
+ * race.  The caller is responsible to use it correctly, for example:
+ *
+ * - from a non-preemptible section (of course)
+ *
+ * - from a thread that is bound to a single CPU
+ *
+ * - in a loop with very short iterations (e.g. a polling loop)
+ */
+bool single_task_running(void)
+{
+	return raw_rq()->nr_running == 1;
+}
+EXPORT_SYMBOL(single_task_running);
+
+unsigned long long nr_context_switches_cpu(int cpu)
+{
+	return cpu_rq(cpu)->nr_switches;
+}
+
+unsigned long long nr_context_switches(void)
+{
+	int i;
+	unsigned long long sum = 0;
+
+	for_each_possible_cpu(i)
+		sum += cpu_rq(i)->nr_switches;
+
+	return sum;
+}
+
+/*
+ * Consumers of these two interfaces, like for example the cpuidle menu
+ * governor, are using nonsensical data. Preferring shallow idle state selection
+ * for a CPU that has IO-wait which might not even end up running the task when
+ * it does become runnable.
+ */
+
+unsigned int nr_iowait_cpu(int cpu)
+{
+	return atomic_read(&cpu_rq(cpu)->nr_iowait);
+}
+
+/*
+ * IO-wait accounting, and how it's mostly bollocks (on SMP).
+ *
+ * The idea behind IO-wait account is to account the idle time that we could
+ * have spend running if it were not for IO. That is, if we were to improve the
+ * storage performance, we'd have a proportional reduction in IO-wait time.
+ *
+ * This all works nicely on UP, where, when a task blocks on IO, we account
+ * idle time as IO-wait, because if the storage were faster, it could've been
+ * running and we'd not be idle.
+ *
+ * This has been extended to SMP, by doing the same for each CPU. This however
+ * is broken.
+ *
+ * Imagine for instance the case where two tasks block on one CPU, only the one
+ * CPU will have IO-wait accounted, while the other has regular idle. Even
+ * though, if the storage were faster, both could've ran at the same time,
+ * utilising both CPUs.
+ *
+ * This means, that when looking globally, the current IO-wait accounting on
+ * SMP is a lower bound, by reason of under accounting.
+ *
+ * Worse, since the numbers are provided per CPU, they are sometimes
+ * interpreted per CPU, and that is nonsensical. A blocked task isn't strictly
+ * associated with any one particular CPU, it can wake to another CPU than it
+ * blocked on. This means the per CPU IO-wait number is meaningless.
+ *
+ * Task CPU affinities can make all that even more 'interesting'.
+ */
+
+unsigned int nr_iowait(void)
+{
+	unsigned int i, sum = 0;
+
+	for_each_possible_cpu(i)
+		sum += nr_iowait_cpu(i);
+
+	return sum;
+}
+
+#ifdef CONFIG_SMP
+
+/*
+ * sched_exec - execve() is a valuable balancing opportunity, because at
+ * this point the task has the smallest effective memory and cache footprint.
+ */
+void sched_exec(void)
+{
+	struct task_struct *p = current;
+	struct migration_arg arg;
+	int dest_cpu;
+
+	scoped_guard (raw_spinlock_irqsave, &p->pi_lock) {
+		dest_cpu = p->sched_class->select_task_rq(p, task_cpu(p), WF_EXEC);
+		if (dest_cpu == smp_processor_id())
+			return;
+
+		if (unlikely(!cpu_active(dest_cpu)))
+			return;
+
+		arg = (struct migration_arg){ p, dest_cpu };
+	}
+	stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg);
+}
+
+#endif
+
+DEFINE_PER_CPU(struct kernel_stat, kstat);
+DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat);
+
+EXPORT_PER_CPU_SYMBOL(kstat);
+EXPORT_PER_CPU_SYMBOL(kernel_cpustat);
+
+/*
+ * The function fair_sched_class.update_curr accesses the struct curr
+ * and its field curr->exec_start; when called from task_sched_runtime(),
+ * we observe a high rate of cache misses in practice.
+ * Prefetching this data results in improved performance.
+ */
+static inline void prefetch_curr_exec_start(struct task_struct *p)
+{
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	struct sched_entity *curr = (&p->se)->cfs_rq->curr;
+#else
+	struct sched_entity *curr = (&task_rq(p)->cfs)->curr;
+#endif
+	prefetch(curr);
+	prefetch(&curr->exec_start);
+}
+
+/*
+ * Return accounted runtime for the task.
+ * In case the task is currently running, return the runtime plus current's
+ * pending runtime that have not been accounted yet.
+ */
+unsigned long long task_sched_runtime(struct task_struct *p)
+{
+	struct rq_flags rf;
+	struct rq *rq;
+	u64 ns;
+
+#if defined(CONFIG_64BIT) && defined(CONFIG_SMP)
+	/*
+	 * 64-bit doesn't need locks to atomically read a 64-bit value.
+	 * So we have a optimization chance when the task's delta_exec is 0.
+	 * Reading ->on_cpu is racy, but this is ok.
+	 *
+	 * If we race with it leaving CPU, we'll take a lock. So we're correct.
+	 * If we race with it entering CPU, unaccounted time is 0. This is
+	 * indistinguishable from the read occurring a few cycles earlier.
+	 * If we see ->on_cpu without ->on_rq, the task is leaving, and has
+	 * been accounted, so we're correct here as well.
+	 */
+	if (!p->on_cpu || !task_on_rq_queued(p))
+		return p->se.sum_exec_runtime;
+#endif
+
+	rq = task_rq_lock(p, &rf);
+	/*
+	 * Must be ->curr _and_ ->on_rq.  If dequeued, we would
+	 * project cycles that may never be accounted to this
+	 * thread, breaking clock_gettime().
+	 */
+	if (task_current(rq, p) && task_on_rq_queued(p)) {
+		prefetch_curr_exec_start(p);
+		update_rq_clock(rq);
+		p->sched_class->update_curr(rq);
+	}
+	ns = p->se.sum_exec_runtime;
+	task_rq_unlock(rq, p, &rf);
+
+	return ns;
+}
+
+#ifdef CONFIG_SCHED_DEBUG
+static u64 cpu_resched_latency(struct rq *rq)
+{
+	int latency_warn_ms = READ_ONCE(sysctl_resched_latency_warn_ms);
+	u64 resched_latency, now = rq_clock(rq);
+	static bool warned_once;
+
+	if (sysctl_resched_latency_warn_once && warned_once)
+		return 0;
+
+	if (!need_resched() || !latency_warn_ms)
+		return 0;
+
+	if (system_state == SYSTEM_BOOTING)
+		return 0;
+
+	if (!rq->last_seen_need_resched_ns) {
+		rq->last_seen_need_resched_ns = now;
+		rq->ticks_without_resched = 0;
+		return 0;
+	}
+
+	rq->ticks_without_resched++;
+	resched_latency = now - rq->last_seen_need_resched_ns;
+	if (resched_latency <= latency_warn_ms * NSEC_PER_MSEC)
+		return 0;
+
+	warned_once = true;
+
+	return resched_latency;
+}
+
+static int __init setup_resched_latency_warn_ms(char *str)
+{
+	long val;
+
+	if ((kstrtol(str, 0, &val))) {
+		pr_warn("Unable to set resched_latency_warn_ms\n");
+		return 1;
+	}
+
+	sysctl_resched_latency_warn_ms = val;
+	return 1;
+}
+__setup("resched_latency_warn_ms=", setup_resched_latency_warn_ms);
+#else
+static inline u64 cpu_resched_latency(struct rq *rq) { return 0; }
+#endif /* CONFIG_SCHED_DEBUG */
+
+/*
+ * This function gets called by the timer code, with HZ frequency.
+ * We call it with interrupts disabled.
+ */
+void scheduler_tick(void)
+{
+	int cpu = smp_processor_id();
+	struct rq *rq = cpu_rq(cpu);
+	struct task_struct *curr = rq->curr;
+	struct rq_flags rf;
+	unsigned long thermal_pressure;
+	u64 resched_latency;
+
+	if (housekeeping_cpu(cpu, HK_TYPE_TICK))
+		arch_scale_freq_tick();
+
+	sched_clock_tick();
+
+	rq_lock(rq, &rf);
+
+	update_rq_clock(rq);
+	thermal_pressure = arch_scale_thermal_pressure(cpu_of(rq));
+	update_thermal_load_avg(rq_clock_thermal(rq), rq, thermal_pressure);
+	curr->sched_class->task_tick(rq, curr, 0);
+	if (sched_feat(LATENCY_WARN))
+		resched_latency = cpu_resched_latency(rq);
+	calc_global_load_tick(rq);
+	sched_core_tick(rq);
+	task_tick_mm_cid(rq, curr);
+
+	rq_unlock(rq, &rf);
+
+	if (sched_feat(LATENCY_WARN) && resched_latency)
+		resched_latency_warn(cpu, resched_latency);
+
+	perf_event_task_tick();
+
+	if (curr->flags & PF_WQ_WORKER)
+		wq_worker_tick(curr);
+
+#ifdef CONFIG_SMP
+	rq->idle_balance = idle_cpu(cpu);
+	trigger_load_balance(rq);
+#endif
+}
+
+#ifdef CONFIG_NO_HZ_FULL
+
+struct tick_work {
+	int			cpu;
+	atomic_t		state;
+	struct delayed_work	work;
+};
+/* Values for ->state, see diagram below. */
+#define TICK_SCHED_REMOTE_OFFLINE	0
+#define TICK_SCHED_REMOTE_OFFLINING	1
+#define TICK_SCHED_REMOTE_RUNNING	2
+
+/*
+ * State diagram for ->state:
+ *
+ *
+ *          TICK_SCHED_REMOTE_OFFLINE
+ *                    |   ^
+ *                    |   |
+ *                    |   | sched_tick_remote()
+ *                    |   |
+ *                    |   |
+ *                    +--TICK_SCHED_REMOTE_OFFLINING
+ *                    |   ^
+ *                    |   |
+ * sched_tick_start() |   | sched_tick_stop()
+ *                    |   |
+ *                    V   |
+ *          TICK_SCHED_REMOTE_RUNNING
+ *
+ *
+ * Other transitions get WARN_ON_ONCE(), except that sched_tick_remote()
+ * and sched_tick_start() are happy to leave the state in RUNNING.
+ */
+
+static struct tick_work __percpu *tick_work_cpu;
+
+static void sched_tick_remote(struct work_struct *work)
+{
+	struct delayed_work *dwork = to_delayed_work(work);
+	struct tick_work *twork = container_of(dwork, struct tick_work, work);
+	int cpu = twork->cpu;
+	struct rq *rq = cpu_rq(cpu);
+	int os;
+
+	/*
+	 * Handle the tick only if it appears the remote CPU is running in full
+	 * dynticks mode. The check is racy by nature, but missing a tick or
+	 * having one too much is no big deal because the scheduler tick updates
+	 * statistics and checks timeslices in a time-independent way, regardless
+	 * of when exactly it is running.
+	 */
+	if (tick_nohz_tick_stopped_cpu(cpu)) {
+		guard(rq_lock_irq)(rq);
+		struct task_struct *curr = rq->curr;
+
+		if (cpu_online(cpu)) {
+			update_rq_clock(rq);
+
+			if (!is_idle_task(curr)) {
+				/*
+				 * Make sure the next tick runs within a
+				 * reasonable amount of time.
+				 */
+				u64 delta = rq_clock_task(rq) - curr->se.exec_start;
+				WARN_ON_ONCE(delta > (u64)NSEC_PER_SEC * 3);
+			}
+			curr->sched_class->task_tick(rq, curr, 0);
+
+			calc_load_nohz_remote(rq);
+		}
+	}
+
+	/*
+	 * Run the remote tick once per second (1Hz). This arbitrary
+	 * frequency is large enough to avoid overload but short enough
+	 * to keep scheduler internal stats reasonably up to date.  But
+	 * first update state to reflect hotplug activity if required.
+	 */
+	os = atomic_fetch_add_unless(&twork->state, -1, TICK_SCHED_REMOTE_RUNNING);
+	WARN_ON_ONCE(os == TICK_SCHED_REMOTE_OFFLINE);
+	if (os == TICK_SCHED_REMOTE_RUNNING)
+		queue_delayed_work(system_unbound_wq, dwork, HZ);
+}
+
+static void sched_tick_start(int cpu)
+{
+	int os;
+	struct tick_work *twork;
+
+	if (housekeeping_cpu(cpu, HK_TYPE_TICK))
+		return;
+
+	WARN_ON_ONCE(!tick_work_cpu);
+
+	twork = per_cpu_ptr(tick_work_cpu, cpu);
+	os = atomic_xchg(&twork->state, TICK_SCHED_REMOTE_RUNNING);
+	WARN_ON_ONCE(os == TICK_SCHED_REMOTE_RUNNING);
+	if (os == TICK_SCHED_REMOTE_OFFLINE) {
+		twork->cpu = cpu;
+		INIT_DELAYED_WORK(&twork->work, sched_tick_remote);
+		queue_delayed_work(system_unbound_wq, &twork->work, HZ);
+	}
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static void sched_tick_stop(int cpu)
+{
+	struct tick_work *twork;
+	int os;
+
+	if (housekeeping_cpu(cpu, HK_TYPE_TICK))
+		return;
+
+	WARN_ON_ONCE(!tick_work_cpu);
+
+	twork = per_cpu_ptr(tick_work_cpu, cpu);
+	/* There cannot be competing actions, but don't rely on stop-machine. */
+	os = atomic_xchg(&twork->state, TICK_SCHED_REMOTE_OFFLINING);
+	WARN_ON_ONCE(os != TICK_SCHED_REMOTE_RUNNING);
+	/* Don't cancel, as this would mess up the state machine. */
+}
+#endif /* CONFIG_HOTPLUG_CPU */
+
+int __init sched_tick_offload_init(void)
+{
+	tick_work_cpu = alloc_percpu(struct tick_work);
+	BUG_ON(!tick_work_cpu);
+	return 0;
+}
+
+#else /* !CONFIG_NO_HZ_FULL */
+static inline void sched_tick_start(int cpu) { }
+static inline void sched_tick_stop(int cpu) { }
+#endif
+
+#if defined(CONFIG_PREEMPTION) && (defined(CONFIG_DEBUG_PREEMPT) || \
+				defined(CONFIG_TRACE_PREEMPT_TOGGLE))
+/*
+ * If the value passed in is equal to the current preempt count
+ * then we just disabled preemption. Start timing the latency.
+ */
+static inline void preempt_latency_start(int val)
+{
+	if (preempt_count() == val) {
+		unsigned long ip = get_lock_parent_ip();
+#ifdef CONFIG_DEBUG_PREEMPT
+		current->preempt_disable_ip = ip;
+#endif
+		trace_preempt_off(CALLER_ADDR0, ip);
+	}
+}
+
+void preempt_count_add(int val)
+{
+#ifdef CONFIG_DEBUG_PREEMPT
+	/*
+	 * Underflow?
+	 */
+	if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
+		return;
+#endif
+	__preempt_count_add(val);
+#ifdef CONFIG_DEBUG_PREEMPT
+	/*
+	 * Spinlock count overflowing soon?
+	 */
+	DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
+				PREEMPT_MASK - 10);
+#endif
+	preempt_latency_start(val);
+}
+EXPORT_SYMBOL(preempt_count_add);
+NOKPROBE_SYMBOL(preempt_count_add);
+
+/*
+ * If the value passed in equals to the current preempt count
+ * then we just enabled preemption. Stop timing the latency.
+ */
+static inline void preempt_latency_stop(int val)
+{
+	if (preempt_count() == val)
+		trace_preempt_on(CALLER_ADDR0, get_lock_parent_ip());
+}
+
+void preempt_count_sub(int val)
+{
+#ifdef CONFIG_DEBUG_PREEMPT
+	/*
+	 * Underflow?
+	 */
+	if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
+		return;
+	/*
+	 * Is the spinlock portion underflowing?
+	 */
+	if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
+			!(preempt_count() & PREEMPT_MASK)))
+		return;
+#endif
+
+	preempt_latency_stop(val);
+	__preempt_count_sub(val);
+}
+EXPORT_SYMBOL(preempt_count_sub);
+NOKPROBE_SYMBOL(preempt_count_sub);
+
+#else
+static inline void preempt_latency_start(int val) { }
+static inline void preempt_latency_stop(int val) { }
+#endif
+
+static inline unsigned long get_preempt_disable_ip(struct task_struct *p)
+{
+#ifdef CONFIG_DEBUG_PREEMPT
+	return p->preempt_disable_ip;
+#else
+	return 0;
+#endif
+}
+
+/*
+ * Print scheduling while atomic bug:
+ */
+static noinline void __schedule_bug(struct task_struct *prev)
+{
+	/* Save this before calling printk(), since that will clobber it */
+	unsigned long preempt_disable_ip = get_preempt_disable_ip(current);
+
+	if (oops_in_progress)
+		return;
+
+	printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
+		prev->comm, prev->pid, preempt_count());
+
+	debug_show_held_locks(prev);
+	print_modules();
+	if (irqs_disabled())
+		print_irqtrace_events(prev);
+	if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)
+	    && in_atomic_preempt_off()) {
+		pr_err("Preemption disabled at:");
+		print_ip_sym(KERN_ERR, preempt_disable_ip);
+	}
+	check_panic_on_warn("scheduling while atomic");
+
+	dump_stack();
+	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
+}
+
+/*
+ * Various schedule()-time debugging checks and statistics:
+ */
+static inline void schedule_debug(struct task_struct *prev, bool preempt)
+{
+#ifdef CONFIG_SCHED_STACK_END_CHECK
+	if (task_stack_end_corrupted(prev))
+		panic("corrupted stack end detected inside scheduler\n");
+
+	if (task_scs_end_corrupted(prev))
+		panic("corrupted shadow stack detected inside scheduler\n");
+#endif
+
+#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
+	if (!preempt && READ_ONCE(prev->__state) && prev->non_block_count) {
+		printk(KERN_ERR "BUG: scheduling in a non-blocking section: %s/%d/%i\n",
+			prev->comm, prev->pid, prev->non_block_count);
+		dump_stack();
+		add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
+	}
+#endif
+
+	if (unlikely(in_atomic_preempt_off())) {
+		__schedule_bug(prev);
+		preempt_count_set(PREEMPT_DISABLED);
+	}
+	rcu_sleep_check();
+	SCHED_WARN_ON(ct_state() == CONTEXT_USER);
+
+	profile_hit(SCHED_PROFILING, __builtin_return_address(0));
+
+	schedstat_inc(this_rq()->sched_count);
+}
+
+static void put_prev_task_balance(struct rq *rq, struct task_struct *prev,
+				  struct rq_flags *rf)
+{
+#ifdef CONFIG_SMP
+	const struct sched_class *class;
+	/*
+	 * We must do the balancing pass before put_prev_task(), such
+	 * that when we release the rq->lock the task is in the same
+	 * state as before we took rq->lock.
+	 *
+	 * We can terminate the balance pass as soon as we know there is
+	 * a runnable task of @class priority or higher.
+	 */
+	for_class_range(class, prev->sched_class, &idle_sched_class) {
+		if (class->balance(rq, prev, rf))
+			break;
+	}
+#endif
+
+	put_prev_task(rq, prev);
+}
+
+/*
+ * Pick up the highest-prio task:
+ */
+static inline struct task_struct *
+__pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
+{
+	const struct sched_class *class;
+	struct task_struct *p;
+
+	/*
+	 * Optimization: we know that if all tasks are in the fair class we can
+	 * call that function directly, but only if the @prev task wasn't of a
+	 * higher scheduling class, because otherwise those lose the
+	 * opportunity to pull in more work from other CPUs.
+	 */
+	if (likely(!sched_class_above(prev->sched_class, &fair_sched_class) &&
+		   rq->nr_running == rq->cfs.h_nr_running)) {
+
+		p = pick_next_task_fair(rq, prev, rf);
+		if (unlikely(p == RETRY_TASK))
+			goto restart;
+
+		/* Assume the next prioritized class is idle_sched_class */
+		if (!p) {
+			put_prev_task(rq, prev);
+			p = pick_next_task_idle(rq);
+		}
+
+		return p;
+	}
+
+restart:
+	put_prev_task_balance(rq, prev, rf);
+
+	for_each_class(class) {
+		p = class->pick_next_task(rq);
+		if (p)
+			return p;
+	}
+
+	BUG(); /* The idle class should always have a runnable task. */
+}
+
+#ifdef CONFIG_SCHED_CORE
+static inline bool is_task_rq_idle(struct task_struct *t)
+{
+	return (task_rq(t)->idle == t);
+}
+
+static inline bool cookie_equals(struct task_struct *a, unsigned long cookie)
+{
+	return is_task_rq_idle(a) || (a->core_cookie == cookie);
+}
+
+static inline bool cookie_match(struct task_struct *a, struct task_struct *b)
+{
+	if (is_task_rq_idle(a) || is_task_rq_idle(b))
+		return true;
+
+	return a->core_cookie == b->core_cookie;
+}
+
+static inline struct task_struct *pick_task(struct rq *rq)
+{
+	const struct sched_class *class;
+	struct task_struct *p;
+
+	for_each_class(class) {
+		p = class->pick_task(rq);
+		if (p)
+			return p;
+	}
+
+	BUG(); /* The idle class should always have a runnable task. */
+}
+
+extern void task_vruntime_update(struct rq *rq, struct task_struct *p, bool in_fi);
+
+static void queue_core_balance(struct rq *rq);
+
+static struct task_struct *
+pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
+{
+	struct task_struct *next, *p, *max = NULL;
+	const struct cpumask *smt_mask;
+	bool fi_before = false;
+	bool core_clock_updated = (rq == rq->core);
+	unsigned long cookie;
+	int i, cpu, occ = 0;
+	struct rq *rq_i;
+	bool need_sync;
+
+	if (!sched_core_enabled(rq))
+		return __pick_next_task(rq, prev, rf);
+
+	cpu = cpu_of(rq);
+
+	/* Stopper task is switching into idle, no need core-wide selection. */
+	if (cpu_is_offline(cpu)) {
+		/*
+		 * Reset core_pick so that we don't enter the fastpath when
+		 * coming online. core_pick would already be migrated to
+		 * another cpu during offline.
+		 */
+		rq->core_pick = NULL;
+		return __pick_next_task(rq, prev, rf);
+	}
+
+	/*
+	 * If there were no {en,de}queues since we picked (IOW, the task
+	 * pointers are all still valid), and we haven't scheduled the last
+	 * pick yet, do so now.
+	 *
+	 * rq->core_pick can be NULL if no selection was made for a CPU because
+	 * it was either offline or went offline during a sibling's core-wide
+	 * selection. In this case, do a core-wide selection.
+	 */
+	if (rq->core->core_pick_seq == rq->core->core_task_seq &&
+	    rq->core->core_pick_seq != rq->core_sched_seq &&
+	    rq->core_pick) {
+		WRITE_ONCE(rq->core_sched_seq, rq->core->core_pick_seq);
+
+		next = rq->core_pick;
+		if (next != prev) {
+			put_prev_task(rq, prev);
+			set_next_task(rq, next);
+		}
+
+		rq->core_pick = NULL;
+		goto out;
+	}
+
+	put_prev_task_balance(rq, prev, rf);
+
+	smt_mask = cpu_smt_mask(cpu);
+	need_sync = !!rq->core->core_cookie;
+
+	/* reset state */
+	rq->core->core_cookie = 0UL;
+	if (rq->core->core_forceidle_count) {
+		if (!core_clock_updated) {
+			update_rq_clock(rq->core);
+			core_clock_updated = true;
+		}
+		sched_core_account_forceidle(rq);
+		/* reset after accounting force idle */
+		rq->core->core_forceidle_start = 0;
+		rq->core->core_forceidle_count = 0;
+		rq->core->core_forceidle_occupation = 0;
+		need_sync = true;
+		fi_before = true;
+	}
+
+	/*
+	 * core->core_task_seq, core->core_pick_seq, rq->core_sched_seq
+	 *
+	 * @task_seq guards the task state ({en,de}queues)
+	 * @pick_seq is the @task_seq we did a selection on
+	 * @sched_seq is the @pick_seq we scheduled
+	 *
+	 * However, preemptions can cause multiple picks on the same task set.
+	 * 'Fix' this by also increasing @task_seq for every pick.
+	 */
+	rq->core->core_task_seq++;
+
+	/*
+	 * Optimize for common case where this CPU has no cookies
+	 * and there are no cookied tasks running on siblings.
+	 */
+	if (!need_sync) {
+		next = pick_task(rq);
+		if (!next->core_cookie) {
+			rq->core_pick = NULL;
+			/*
+			 * For robustness, update the min_vruntime_fi for
+			 * unconstrained picks as well.
+			 */
+			WARN_ON_ONCE(fi_before);
+			task_vruntime_update(rq, next, false);
+			goto out_set_next;
+		}
+	}
+
+	/*
+	 * For each thread: do the regular task pick and find the max prio task
+	 * amongst them.
+	 *
+	 * Tie-break prio towards the current CPU
+	 */
+	for_each_cpu_wrap(i, smt_mask, cpu) {
+		rq_i = cpu_rq(i);
+
+		/*
+		 * Current cpu always has its clock updated on entrance to
+		 * pick_next_task(). If the current cpu is not the core,
+		 * the core may also have been updated above.
+		 */
+		if (i != cpu && (rq_i != rq->core || !core_clock_updated))
+			update_rq_clock(rq_i);
+
+		p = rq_i->core_pick = pick_task(rq_i);
+		if (!max || prio_less(max, p, fi_before))
+			max = p;
+	}
+
+	cookie = rq->core->core_cookie = max->core_cookie;
+
+	/*
+	 * For each thread: try and find a runnable task that matches @max or
+	 * force idle.
+	 */
+	for_each_cpu(i, smt_mask) {
+		rq_i = cpu_rq(i);
+		p = rq_i->core_pick;
+
+		if (!cookie_equals(p, cookie)) {
+			p = NULL;
+			if (cookie)
+				p = sched_core_find(rq_i, cookie);
+			if (!p)
+				p = idle_sched_class.pick_task(rq_i);
+		}
+
+		rq_i->core_pick = p;
+
+		if (p == rq_i->idle) {
+			if (rq_i->nr_running) {
+				rq->core->core_forceidle_count++;
+				if (!fi_before)
+					rq->core->core_forceidle_seq++;
+			}
+		} else {
+			occ++;
+		}
+	}
+
+	if (schedstat_enabled() && rq->core->core_forceidle_count) {
+		rq->core->core_forceidle_start = rq_clock(rq->core);
+		rq->core->core_forceidle_occupation = occ;
+	}
+
+	rq->core->core_pick_seq = rq->core->core_task_seq;
+	next = rq->core_pick;
+	rq->core_sched_seq = rq->core->core_pick_seq;
+
+	/* Something should have been selected for current CPU */
+	WARN_ON_ONCE(!next);
+
+	/*
+	 * Reschedule siblings
+	 *
+	 * NOTE: L1TF -- at this point we're no longer running the old task and
+	 * sending an IPI (below) ensures the sibling will no longer be running
+	 * their task. This ensures there is no inter-sibling overlap between
+	 * non-matching user state.
+	 */
+	for_each_cpu(i, smt_mask) {
+		rq_i = cpu_rq(i);
+
+		/*
+		 * An online sibling might have gone offline before a task
+		 * could be picked for it, or it might be offline but later
+		 * happen to come online, but its too late and nothing was
+		 * picked for it.  That's Ok - it will pick tasks for itself,
+		 * so ignore it.
+		 */
+		if (!rq_i->core_pick)
+			continue;
+
+		/*
+		 * Update for new !FI->FI transitions, or if continuing to be in !FI:
+		 * fi_before     fi      update?
+		 *  0            0       1
+		 *  0            1       1
+		 *  1            0       1
+		 *  1            1       0
+		 */
+		if (!(fi_before && rq->core->core_forceidle_count))
+			task_vruntime_update(rq_i, rq_i->core_pick, !!rq->core->core_forceidle_count);
+
+		rq_i->core_pick->core_occupation = occ;
+
+		if (i == cpu) {
+			rq_i->core_pick = NULL;
+			continue;
+		}
+
+		/* Did we break L1TF mitigation requirements? */
+		WARN_ON_ONCE(!cookie_match(next, rq_i->core_pick));
+
+		if (rq_i->curr == rq_i->core_pick) {
+			rq_i->core_pick = NULL;
+			continue;
+		}
+
+		resched_curr(rq_i);
+	}
+
+out_set_next:
+	set_next_task(rq, next);
+out:
+	if (rq->core->core_forceidle_count && next == rq->idle)
+		queue_core_balance(rq);
+
+	return next;
+}
+
+static bool try_steal_cookie(int this, int that)
+{
+	struct rq *dst = cpu_rq(this), *src = cpu_rq(that);
+	struct task_struct *p;
+	unsigned long cookie;
+	bool success = false;
+
+	guard(irq)();
+	guard(double_rq_lock)(dst, src);
+
+	cookie = dst->core->core_cookie;
+	if (!cookie)
+		return false;
+
+	if (dst->curr != dst->idle)
+		return false;
+
+	p = sched_core_find(src, cookie);
+	if (!p)
+		return false;
+
+	do {
+		if (p == src->core_pick || p == src->curr)
+			goto next;
+
+		if (!is_cpu_allowed(p, this))
+			goto next;
+
+		if (p->core_occupation > dst->idle->core_occupation)
+			goto next;
+		/*
+		 * sched_core_find() and sched_core_next() will ensure
+		 * that task @p is not throttled now, we also need to
+		 * check whether the runqueue of the destination CPU is
+		 * being throttled.
+		 */
+		if (sched_task_is_throttled(p, this))
+			goto next;
+
+		deactivate_task(src, p, 0);
+		set_task_cpu(p, this);
+		activate_task(dst, p, 0);
+
+		resched_curr(dst);
+
+		success = true;
+		break;
+
+next:
+		p = sched_core_next(p, cookie);
+	} while (p);
+
+	return success;
+}
+
+static bool steal_cookie_task(int cpu, struct sched_domain *sd)
+{
+	int i;
+
+	for_each_cpu_wrap(i, sched_domain_span(sd), cpu + 1) {
+		if (i == cpu)
+			continue;
+
+		if (need_resched())
+			break;
+
+		if (try_steal_cookie(cpu, i))
+			return true;
+	}
+
+	return false;
+}
+
+static void sched_core_balance(struct rq *rq)
+{
+	struct sched_domain *sd;
+	int cpu = cpu_of(rq);
+
+	preempt_disable();
+	rcu_read_lock();
+	raw_spin_rq_unlock_irq(rq);
+	for_each_domain(cpu, sd) {
+		if (need_resched())
+			break;
+
+		if (steal_cookie_task(cpu, sd))
+			break;
+	}
+	raw_spin_rq_lock_irq(rq);
+	rcu_read_unlock();
+	preempt_enable();
+}
+
+static DEFINE_PER_CPU(struct balance_callback, core_balance_head);
+
+static void queue_core_balance(struct rq *rq)
+{
+	if (!sched_core_enabled(rq))
+		return;
+
+	if (!rq->core->core_cookie)
+		return;
+
+	if (!rq->nr_running) /* not forced idle */
+		return;
+
+	queue_balance_callback(rq, &per_cpu(core_balance_head, rq->cpu), sched_core_balance);
+}
+
+DEFINE_LOCK_GUARD_1(core_lock, int,
+		    sched_core_lock(*_T->lock, &_T->flags),
+		    sched_core_unlock(*_T->lock, &_T->flags),
+		    unsigned long flags)
+
+static void sched_core_cpu_starting(unsigned int cpu)
+{
+	const struct cpumask *smt_mask = cpu_smt_mask(cpu);
+	struct rq *rq = cpu_rq(cpu), *core_rq = NULL;
+	int t;
+
+	guard(core_lock)(&cpu);
+
+	WARN_ON_ONCE(rq->core != rq);
+
+	/* if we're the first, we'll be our own leader */
+	if (cpumask_weight(smt_mask) == 1)
+		return;
+
+	/* find the leader */
+	for_each_cpu(t, smt_mask) {
+		if (t == cpu)
+			continue;
+		rq = cpu_rq(t);
+		if (rq->core == rq) {
+			core_rq = rq;
+			break;
+		}
+	}
+
+	if (WARN_ON_ONCE(!core_rq)) /* whoopsie */
+		return;
+
+	/* install and validate core_rq */
+	for_each_cpu(t, smt_mask) {
+		rq = cpu_rq(t);
+
+		if (t == cpu)
+			rq->core = core_rq;
+
+		WARN_ON_ONCE(rq->core != core_rq);
+	}
+}
+
+static void sched_core_cpu_deactivate(unsigned int cpu)
+{
+	const struct cpumask *smt_mask = cpu_smt_mask(cpu);
+	struct rq *rq = cpu_rq(cpu), *core_rq = NULL;
+	int t;
+
+	guard(core_lock)(&cpu);
+
+	/* if we're the last man standing, nothing to do */
+	if (cpumask_weight(smt_mask) == 1) {
+		WARN_ON_ONCE(rq->core != rq);
+		return;
+	}
+
+	/* if we're not the leader, nothing to do */
+	if (rq->core != rq)
+		return;
+
+	/* find a new leader */
+	for_each_cpu(t, smt_mask) {
+		if (t == cpu)
+			continue;
+		core_rq = cpu_rq(t);
+		break;
+	}
+
+	if (WARN_ON_ONCE(!core_rq)) /* impossible */
+		return;
+
+	/* copy the shared state to the new leader */
+	core_rq->core_task_seq             = rq->core_task_seq;
+	core_rq->core_pick_seq             = rq->core_pick_seq;
+	core_rq->core_cookie               = rq->core_cookie;
+	core_rq->core_forceidle_count      = rq->core_forceidle_count;
+	core_rq->core_forceidle_seq        = rq->core_forceidle_seq;
+	core_rq->core_forceidle_occupation = rq->core_forceidle_occupation;
+
+	/*
+	 * Accounting edge for forced idle is handled in pick_next_task().
+	 * Don't need another one here, since the hotplug thread shouldn't
+	 * have a cookie.
+	 */
+	core_rq->core_forceidle_start = 0;
+
+	/* install new leader */
+	for_each_cpu(t, smt_mask) {
+		rq = cpu_rq(t);
+		rq->core = core_rq;
+	}
+}
+
+static inline void sched_core_cpu_dying(unsigned int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	if (rq->core != rq)
+		rq->core = rq;
+}
+
+#else /* !CONFIG_SCHED_CORE */
+
+static inline void sched_core_cpu_starting(unsigned int cpu) {}
+static inline void sched_core_cpu_deactivate(unsigned int cpu) {}
+static inline void sched_core_cpu_dying(unsigned int cpu) {}
+
+static struct task_struct *
+pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
+{
+	return __pick_next_task(rq, prev, rf);
+}
+
+#endif /* CONFIG_SCHED_CORE */
+
+/*
+ * Constants for the sched_mode argument of __schedule().
+ *
+ * The mode argument allows RT enabled kernels to differentiate a
+ * preemption from blocking on an 'sleeping' spin/rwlock. Note that
+ * SM_MASK_PREEMPT for !RT has all bits set, which allows the compiler to
+ * optimize the AND operation out and just check for zero.
+ */
+#define SM_NONE			0x0
+#define SM_PREEMPT		0x1
+#define SM_RTLOCK_WAIT		0x2
+
+#ifndef CONFIG_PREEMPT_RT
+# define SM_MASK_PREEMPT	(~0U)
+#else
+# define SM_MASK_PREEMPT	SM_PREEMPT
+#endif
+
+/*
+ * __schedule() is the main scheduler function.
+ *
+ * The main means of driving the scheduler and thus entering this function are:
+ *
+ *   1. Explicit blocking: mutex, semaphore, waitqueue, etc.
+ *
+ *   2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
+ *      paths. For example, see arch/x86/entry_64.S.
+ *
+ *      To drive preemption between tasks, the scheduler sets the flag in timer
+ *      interrupt handler scheduler_tick().
+ *
+ *   3. Wakeups don't really cause entry into schedule(). They add a
+ *      task to the run-queue and that's it.
+ *
+ *      Now, if the new task added to the run-queue preempts the current
+ *      task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
+ *      called on the nearest possible occasion:
+ *
+ *       - If the kernel is preemptible (CONFIG_PREEMPTION=y):
+ *
+ *         - in syscall or exception context, at the next outmost
+ *           preempt_enable(). (this might be as soon as the wake_up()'s
+ *           spin_unlock()!)
+ *
+ *         - in IRQ context, return from interrupt-handler to
+ *           preemptible context
+ *
+ *       - If the kernel is not preemptible (CONFIG_PREEMPTION is not set)
+ *         then at the next:
+ *
+ *          - cond_resched() call
+ *          - explicit schedule() call
+ *          - return from syscall or exception to user-space
+ *          - return from interrupt-handler to user-space
+ *
+ * WARNING: must be called with preemption disabled!
+ */
+static void __sched notrace __schedule(unsigned int sched_mode)
+{
+	struct task_struct *prev, *next;
+	unsigned long *switch_count;
+	unsigned long prev_state;
+	struct rq_flags rf;
+	struct rq *rq;
+	int cpu;
+
+	cpu = smp_processor_id();
+	rq = cpu_rq(cpu);
+	prev = rq->curr;
+
+	schedule_debug(prev, !!sched_mode);
+
+	if (sched_feat(HRTICK) || sched_feat(HRTICK_DL))
+		hrtick_clear(rq);
+
+	local_irq_disable();
+	rcu_note_context_switch(!!sched_mode);
+
+	/*
+	 * Make sure that signal_pending_state()->signal_pending() below
+	 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
+	 * done by the caller to avoid the race with signal_wake_up():
+	 *
+	 * __set_current_state(@state)		signal_wake_up()
+	 * schedule()				  set_tsk_thread_flag(p, TIF_SIGPENDING)
+	 *					  wake_up_state(p, state)
+	 *   LOCK rq->lock			    LOCK p->pi_state
+	 *   smp_mb__after_spinlock()		    smp_mb__after_spinlock()
+	 *     if (signal_pending_state())	    if (p->state & @state)
+	 *
+	 * Also, the membarrier system call requires a full memory barrier
+	 * after coming from user-space, before storing to rq->curr.
+	 */
+	rq_lock(rq, &rf);
+	smp_mb__after_spinlock();
+
+	/* Promote REQ to ACT */
+	rq->clock_update_flags <<= 1;
+	update_rq_clock(rq);
+	rq->clock_update_flags = RQCF_UPDATED;
+
+	switch_count = &prev->nivcsw;
+
+	/*
+	 * We must load prev->state once (task_struct::state is volatile), such
+	 * that we form a control dependency vs deactivate_task() below.
+	 */
+	prev_state = READ_ONCE(prev->__state);
+	if (!(sched_mode & SM_MASK_PREEMPT) && prev_state) {
+		if (signal_pending_state(prev_state, prev)) {
+			WRITE_ONCE(prev->__state, TASK_RUNNING);
+		} else {
+			prev->sched_contributes_to_load =
+				(prev_state & TASK_UNINTERRUPTIBLE) &&
+				!(prev_state & TASK_NOLOAD) &&
+				!(prev_state & TASK_FROZEN);
+
+			if (prev->sched_contributes_to_load)
+				rq->nr_uninterruptible++;
+
+			/*
+			 * __schedule()			ttwu()
+			 *   prev_state = prev->state;    if (p->on_rq && ...)
+			 *   if (prev_state)		    goto out;
+			 *     p->on_rq = 0;		  smp_acquire__after_ctrl_dep();
+			 *				  p->state = TASK_WAKING
+			 *
+			 * Where __schedule() and ttwu() have matching control dependencies.
+			 *
+			 * After this, schedule() must not care about p->state any more.
+			 */
+			deactivate_task(rq, prev, DEQUEUE_SLEEP | DEQUEUE_NOCLOCK);
+
+			if (prev->in_iowait) {
+				atomic_inc(&rq->nr_iowait);
+				delayacct_blkio_start();
+			}
+		}
+		switch_count = &prev->nvcsw;
+	}
+
+	next = pick_next_task(rq, prev, &rf);
+	clear_tsk_need_resched(prev);
+	clear_preempt_need_resched();
+#ifdef CONFIG_SCHED_DEBUG
+	rq->last_seen_need_resched_ns = 0;
+#endif
+
+	if (likely(prev != next)) {
+		rq->nr_switches++;
+		/*
+		 * RCU users of rcu_dereference(rq->curr) may not see
+		 * changes to task_struct made by pick_next_task().
+		 */
+		RCU_INIT_POINTER(rq->curr, next);
+		/*
+		 * The membarrier system call requires each architecture
+		 * to have a full memory barrier after updating
+		 * rq->curr, before returning to user-space.
+		 *
+		 * Here are the schemes providing that barrier on the
+		 * various architectures:
+		 * - mm ? switch_mm() : mmdrop() for x86, s390, sparc, PowerPC.
+		 *   switch_mm() rely on membarrier_arch_switch_mm() on PowerPC.
+		 * - finish_lock_switch() for weakly-ordered
+		 *   architectures where spin_unlock is a full barrier,
+		 * - switch_to() for arm64 (weakly-ordered, spin_unlock
+		 *   is a RELEASE barrier),
+		 */
+		++*switch_count;
+
+		migrate_disable_switch(rq, prev);
+		psi_sched_switch(prev, next, !task_on_rq_queued(prev));
+
+		trace_sched_switch(sched_mode & SM_MASK_PREEMPT, prev, next, prev_state);
+
+		/* Also unlocks the rq: */
+		rq = context_switch(rq, prev, next, &rf);
+	} else {
+		rq_unpin_lock(rq, &rf);
+		__balance_callbacks(rq);
+		raw_spin_rq_unlock_irq(rq);
+	}
+}
+
+void __noreturn do_task_dead(void)
+{
+	/* Causes final put_task_struct in finish_task_switch(): */
+	set_special_state(TASK_DEAD);
+
+	/* Tell freezer to ignore us: */
+	current->flags |= PF_NOFREEZE;
+
+	__schedule(SM_NONE);
+	BUG();
+
+	/* Avoid "noreturn function does return" - but don't continue if BUG() is a NOP: */
+	for (;;)
+		cpu_relax();
+}
+
+static inline void sched_submit_work(struct task_struct *tsk)
+{
+	unsigned int task_flags;
+
+	if (task_is_running(tsk))
+		return;
+
+	task_flags = tsk->flags;
+	/*
+	 * If a worker goes to sleep, notify and ask workqueue whether it
+	 * wants to wake up a task to maintain concurrency.
+	 */
+	if (task_flags & (PF_WQ_WORKER | PF_IO_WORKER)) {
+		if (task_flags & PF_WQ_WORKER)
+			wq_worker_sleeping(tsk);
+		else
+			io_wq_worker_sleeping(tsk);
+	}
+
+	/*
+	 * spinlock and rwlock must not flush block requests.  This will
+	 * deadlock if the callback attempts to acquire a lock which is
+	 * already acquired.
+	 */
+	SCHED_WARN_ON(current->__state & TASK_RTLOCK_WAIT);
+
+	/*
+	 * If we are going to sleep and we have plugged IO queued,
+	 * make sure to submit it to avoid deadlocks.
+	 */
+	blk_flush_plug(tsk->plug, true);
+}
+
+static void sched_update_worker(struct task_struct *tsk)
+{
+	if (tsk->flags & (PF_WQ_WORKER | PF_IO_WORKER)) {
+		if (tsk->flags & PF_WQ_WORKER)
+			wq_worker_running(tsk);
+		else
+			io_wq_worker_running(tsk);
+	}
+}
+
+asmlinkage __visible void __sched schedule(void)
+{
+	struct task_struct *tsk = current;
+
+	sched_submit_work(tsk);
+	do {
+		preempt_disable();
+		__schedule(SM_NONE);
+		sched_preempt_enable_no_resched();
+	} while (need_resched());
+	sched_update_worker(tsk);
+}
+EXPORT_SYMBOL(schedule);
+
+/*
+ * synchronize_rcu_tasks() makes sure that no task is stuck in preempted
+ * state (have scheduled out non-voluntarily) by making sure that all
+ * tasks have either left the run queue or have gone into user space.
+ * As idle tasks do not do either, they must not ever be preempted
+ * (schedule out non-voluntarily).
+ *
+ * schedule_idle() is similar to schedule_preempt_disable() except that it
+ * never enables preemption because it does not call sched_submit_work().
+ */
+void __sched schedule_idle(void)
+{
+	/*
+	 * As this skips calling sched_submit_work(), which the idle task does
+	 * regardless because that function is a nop when the task is in a
+	 * TASK_RUNNING state, make sure this isn't used someplace that the
+	 * current task can be in any other state. Note, idle is always in the
+	 * TASK_RUNNING state.
+	 */
+	WARN_ON_ONCE(current->__state);
+	do {
+		__schedule(SM_NONE);
+	} while (need_resched());
+}
+
+#if defined(CONFIG_CONTEXT_TRACKING_USER) && !defined(CONFIG_HAVE_CONTEXT_TRACKING_USER_OFFSTACK)
+asmlinkage __visible void __sched schedule_user(void)
+{
+	/*
+	 * If we come here after a random call to set_need_resched(),
+	 * or we have been woken up remotely but the IPI has not yet arrived,
+	 * we haven't yet exited the RCU idle mode. Do it here manually until
+	 * we find a better solution.
+	 *
+	 * NB: There are buggy callers of this function.  Ideally we
+	 * should warn if prev_state != CONTEXT_USER, but that will trigger
+	 * too frequently to make sense yet.
+	 */
+	enum ctx_state prev_state = exception_enter();
+	schedule();
+	exception_exit(prev_state);
+}
+#endif
+
+/**
+ * schedule_preempt_disabled - called with preemption disabled
+ *
+ * Returns with preemption disabled. Note: preempt_count must be 1
+ */
+void __sched schedule_preempt_disabled(void)
+{
+	sched_preempt_enable_no_resched();
+	schedule();
+	preempt_disable();
+}
+
+#ifdef CONFIG_PREEMPT_RT
+void __sched notrace schedule_rtlock(void)
+{
+	do {
+		preempt_disable();
+		__schedule(SM_RTLOCK_WAIT);
+		sched_preempt_enable_no_resched();
+	} while (need_resched());
+}
+NOKPROBE_SYMBOL(schedule_rtlock);
+#endif
+
+static void __sched notrace preempt_schedule_common(void)
+{
+	do {
+		/*
+		 * Because the function tracer can trace preempt_count_sub()
+		 * and it also uses preempt_enable/disable_notrace(), if
+		 * NEED_RESCHED is set, the preempt_enable_notrace() called
+		 * by the function tracer will call this function again and
+		 * cause infinite recursion.
+		 *
+		 * Preemption must be disabled here before the function
+		 * tracer can trace. Break up preempt_disable() into two
+		 * calls. One to disable preemption without fear of being
+		 * traced. The other to still record the preemption latency,
+		 * which can also be traced by the function tracer.
+		 */
+		preempt_disable_notrace();
+		preempt_latency_start(1);
+		__schedule(SM_PREEMPT);
+		preempt_latency_stop(1);
+		preempt_enable_no_resched_notrace();
+
+		/*
+		 * Check again in case we missed a preemption opportunity
+		 * between schedule and now.
+		 */
+	} while (need_resched());
+}
+
+#ifdef CONFIG_PREEMPTION
+/*
+ * This is the entry point to schedule() from in-kernel preemption
+ * off of preempt_enable.
+ */
+asmlinkage __visible void __sched notrace preempt_schedule(void)
+{
+	/*
+	 * If there is a non-zero preempt_count or interrupts are disabled,
+	 * we do not want to preempt the current task. Just return..
+	 */
+	if (likely(!preemptible()))
+		return;
+	preempt_schedule_common();
+}
+NOKPROBE_SYMBOL(preempt_schedule);
+EXPORT_SYMBOL(preempt_schedule);
+
+#ifdef CONFIG_PREEMPT_DYNAMIC
+#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL)
+#ifndef preempt_schedule_dynamic_enabled
+#define preempt_schedule_dynamic_enabled	preempt_schedule
+#define preempt_schedule_dynamic_disabled	NULL
+#endif
+DEFINE_STATIC_CALL(preempt_schedule, preempt_schedule_dynamic_enabled);
+EXPORT_STATIC_CALL_TRAMP(preempt_schedule);
+#elif defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY)
+static DEFINE_STATIC_KEY_TRUE(sk_dynamic_preempt_schedule);
+void __sched notrace dynamic_preempt_schedule(void)
+{
+	if (!static_branch_unlikely(&sk_dynamic_preempt_schedule))
+		return;
+	preempt_schedule();
+}
+NOKPROBE_SYMBOL(dynamic_preempt_schedule);
+EXPORT_SYMBOL(dynamic_preempt_schedule);
+#endif
+#endif
+
+/**
+ * preempt_schedule_notrace - preempt_schedule called by tracing
+ *
+ * The tracing infrastructure uses preempt_enable_notrace to prevent
+ * recursion and tracing preempt enabling caused by the tracing
+ * infrastructure itself. But as tracing can happen in areas coming
+ * from userspace or just about to enter userspace, a preempt enable
+ * can occur before user_exit() is called. This will cause the scheduler
+ * to be called when the system is still in usermode.
+ *
+ * To prevent this, the preempt_enable_notrace will use this function
+ * instead of preempt_schedule() to exit user context if needed before
+ * calling the scheduler.
+ */
+asmlinkage __visible void __sched notrace preempt_schedule_notrace(void)
+{
+	enum ctx_state prev_ctx;
+
+	if (likely(!preemptible()))
+		return;
+
+	do {
+		/*
+		 * Because the function tracer can trace preempt_count_sub()
+		 * and it also uses preempt_enable/disable_notrace(), if
+		 * NEED_RESCHED is set, the preempt_enable_notrace() called
+		 * by the function tracer will call this function again and
+		 * cause infinite recursion.
+		 *
+		 * Preemption must be disabled here before the function
+		 * tracer can trace. Break up preempt_disable() into two
+		 * calls. One to disable preemption without fear of being
+		 * traced. The other to still record the preemption latency,
+		 * which can also be traced by the function tracer.
+		 */
+		preempt_disable_notrace();
+		preempt_latency_start(1);
+		/*
+		 * Needs preempt disabled in case user_exit() is traced
+		 * and the tracer calls preempt_enable_notrace() causing
+		 * an infinite recursion.
+		 */
+		prev_ctx = exception_enter();
+		__schedule(SM_PREEMPT);
+		exception_exit(prev_ctx);
+
+		preempt_latency_stop(1);
+		preempt_enable_no_resched_notrace();
+	} while (need_resched());
+}
+EXPORT_SYMBOL_GPL(preempt_schedule_notrace);
+
+#ifdef CONFIG_PREEMPT_DYNAMIC
+#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL)
+#ifndef preempt_schedule_notrace_dynamic_enabled
+#define preempt_schedule_notrace_dynamic_enabled	preempt_schedule_notrace
+#define preempt_schedule_notrace_dynamic_disabled	NULL
+#endif
+DEFINE_STATIC_CALL(preempt_schedule_notrace, preempt_schedule_notrace_dynamic_enabled);
+EXPORT_STATIC_CALL_TRAMP(preempt_schedule_notrace);
+#elif defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY)
+static DEFINE_STATIC_KEY_TRUE(sk_dynamic_preempt_schedule_notrace);
+void __sched notrace dynamic_preempt_schedule_notrace(void)
+{
+	if (!static_branch_unlikely(&sk_dynamic_preempt_schedule_notrace))
+		return;
+	preempt_schedule_notrace();
+}
+NOKPROBE_SYMBOL(dynamic_preempt_schedule_notrace);
+EXPORT_SYMBOL(dynamic_preempt_schedule_notrace);
+#endif
+#endif
+
+#endif /* CONFIG_PREEMPTION */
+
+/*
+ * This is the entry point to schedule() from kernel preemption
+ * off of irq context.
+ * Note, that this is called and return with irqs disabled. This will
+ * protect us against recursive calling from irq.
+ */
+asmlinkage __visible void __sched preempt_schedule_irq(void)
+{
+	enum ctx_state prev_state;
+
+	/* Catch callers which need to be fixed */
+	BUG_ON(preempt_count() || !irqs_disabled());
+
+	prev_state = exception_enter();
+
+	do {
+		preempt_disable();
+		local_irq_enable();
+		__schedule(SM_PREEMPT);
+		local_irq_disable();
+		sched_preempt_enable_no_resched();
+	} while (need_resched());
+
+	exception_exit(prev_state);
+}
+
+int default_wake_function(wait_queue_entry_t *curr, unsigned mode, int wake_flags,
+			  void *key)
+{
+	WARN_ON_ONCE(IS_ENABLED(CONFIG_SCHED_DEBUG) && wake_flags & ~(WF_SYNC|WF_CURRENT_CPU));
+	return try_to_wake_up(curr->private, mode, wake_flags);
+}
+EXPORT_SYMBOL(default_wake_function);
+
+static void __setscheduler_prio(struct task_struct *p, int prio)
+{
+	if (dl_prio(prio))
+		p->sched_class = &dl_sched_class;
+	else if (rt_prio(prio))
+		p->sched_class = &rt_sched_class;
+	else
+		p->sched_class = &fair_sched_class;
+
+	p->prio = prio;
+}
+
+#ifdef CONFIG_RT_MUTEXES
+
+static inline int __rt_effective_prio(struct task_struct *pi_task, int prio)
+{
+	if (pi_task)
+		prio = min(prio, pi_task->prio);
+
+	return prio;
+}
+
+static inline int rt_effective_prio(struct task_struct *p, int prio)
+{
+	struct task_struct *pi_task = rt_mutex_get_top_task(p);
+
+	return __rt_effective_prio(pi_task, prio);
+}
+
+/*
+ * rt_mutex_setprio - set the current priority of a task
+ * @p: task to boost
+ * @pi_task: donor task
+ *
+ * This function changes the 'effective' priority of a task. It does
+ * not touch ->normal_prio like __setscheduler().
+ *
+ * Used by the rt_mutex code to implement priority inheritance
+ * logic. Call site only calls if the priority of the task changed.
+ */
+void rt_mutex_setprio(struct task_struct *p, struct task_struct *pi_task)
+{
+	int prio, oldprio, queued, running, queue_flag =
+		DEQUEUE_SAVE | DEQUEUE_MOVE | DEQUEUE_NOCLOCK;
+	const struct sched_class *prev_class;
+	struct rq_flags rf;
+	struct rq *rq;
+
+	/* XXX used to be waiter->prio, not waiter->task->prio */
+	prio = __rt_effective_prio(pi_task, p->normal_prio);
+
+	/*
+	 * If nothing changed; bail early.
+	 */
+	if (p->pi_top_task == pi_task && prio == p->prio && !dl_prio(prio))
+		return;
+
+	rq = __task_rq_lock(p, &rf);
+	update_rq_clock(rq);
+	/*
+	 * Set under pi_lock && rq->lock, such that the value can be used under
+	 * either lock.
+	 *
+	 * Note that there is loads of tricky to make this pointer cache work
+	 * right. rt_mutex_slowunlock()+rt_mutex_postunlock() work together to
+	 * ensure a task is de-boosted (pi_task is set to NULL) before the
+	 * task is allowed to run again (and can exit). This ensures the pointer
+	 * points to a blocked task -- which guarantees the task is present.
+	 */
+	p->pi_top_task = pi_task;
+
+	/*
+	 * For FIFO/RR we only need to set prio, if that matches we're done.
+	 */
+	if (prio == p->prio && !dl_prio(prio))
+		goto out_unlock;
+
+	/*
+	 * Idle task boosting is a nono in general. There is one
+	 * exception, when PREEMPT_RT and NOHZ is active:
+	 *
+	 * The idle task calls get_next_timer_interrupt() and holds
+	 * the timer wheel base->lock on the CPU and another CPU wants
+	 * to access the timer (probably to cancel it). We can safely
+	 * ignore the boosting request, as the idle CPU runs this code
+	 * with interrupts disabled and will complete the lock
+	 * protected section without being interrupted. So there is no
+	 * real need to boost.
+	 */
+	if (unlikely(p == rq->idle)) {
+		WARN_ON(p != rq->curr);
+		WARN_ON(p->pi_blocked_on);
+		goto out_unlock;
+	}
+
+	trace_sched_pi_setprio(p, pi_task);
+	oldprio = p->prio;
+
+	if (oldprio == prio)
+		queue_flag &= ~DEQUEUE_MOVE;
+
+	prev_class = p->sched_class;
+	queued = task_on_rq_queued(p);
+	running = task_current(rq, p);
+	if (queued)
+		dequeue_task(rq, p, queue_flag);
+	if (running)
+		put_prev_task(rq, p);
+
+	/*
+	 * Boosting condition are:
+	 * 1. -rt task is running and holds mutex A
+	 *      --> -dl task blocks on mutex A
+	 *
+	 * 2. -dl task is running and holds mutex A
+	 *      --> -dl task blocks on mutex A and could preempt the
+	 *          running task
+	 */
+	if (dl_prio(prio)) {
+		if (!dl_prio(p->normal_prio) ||
+		    (pi_task && dl_prio(pi_task->prio) &&
+		     dl_entity_preempt(&pi_task->dl, &p->dl))) {
+			p->dl.pi_se = pi_task->dl.pi_se;
+			queue_flag |= ENQUEUE_REPLENISH;
+		} else {
+			p->dl.pi_se = &p->dl;
+		}
+	} else if (rt_prio(prio)) {
+		if (dl_prio(oldprio))
+			p->dl.pi_se = &p->dl;
+		if (oldprio < prio)
+			queue_flag |= ENQUEUE_HEAD;
+	} else {
+		if (dl_prio(oldprio))
+			p->dl.pi_se = &p->dl;
+		if (rt_prio(oldprio))
+			p->rt.timeout = 0;
+	}
+
+	__setscheduler_prio(p, prio);
+
+	if (queued)
+		enqueue_task(rq, p, queue_flag);
+	if (running)
+		set_next_task(rq, p);
+
+	check_class_changed(rq, p, prev_class, oldprio);
+out_unlock:
+	/* Avoid rq from going away on us: */
+	preempt_disable();
+
+	rq_unpin_lock(rq, &rf);
+	__balance_callbacks(rq);
+	raw_spin_rq_unlock(rq);
+
+	preempt_enable();
+}
+#else
+static inline int rt_effective_prio(struct task_struct *p, int prio)
+{
+	return prio;
+}
+#endif
+
+void set_user_nice(struct task_struct *p, long nice)
+{
+	bool queued, running;
+	int old_prio;
+	struct rq_flags rf;
+	struct rq *rq;
+
+	if (task_nice(p) == nice || nice < MIN_NICE || nice > MAX_NICE)
+		return;
+	/*
+	 * We have to be careful, if called from sys_setpriority(),
+	 * the task might be in the middle of scheduling on another CPU.
+	 */
+	rq = task_rq_lock(p, &rf);
+	update_rq_clock(rq);
+
+	/*
+	 * The RT priorities are set via sched_setscheduler(), but we still
+	 * allow the 'normal' nice value to be set - but as expected
+	 * it won't have any effect on scheduling until the task is
+	 * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR:
+	 */
+	if (task_has_dl_policy(p) || task_has_rt_policy(p)) {
+		p->static_prio = NICE_TO_PRIO(nice);
+		goto out_unlock;
+	}
+	queued = task_on_rq_queued(p);
+	running = task_current(rq, p);
+	if (queued)
+		dequeue_task(rq, p, DEQUEUE_SAVE | DEQUEUE_NOCLOCK);
+	if (running)
+		put_prev_task(rq, p);
+
+	p->static_prio = NICE_TO_PRIO(nice);
+	set_load_weight(p, true);
+	old_prio = p->prio;
+	p->prio = effective_prio(p);
+
+	if (queued)
+		enqueue_task(rq, p, ENQUEUE_RESTORE | ENQUEUE_NOCLOCK);
+	if (running)
+		set_next_task(rq, p);
+
+	/*
+	 * If the task increased its priority or is running and
+	 * lowered its priority, then reschedule its CPU:
+	 */
+	p->sched_class->prio_changed(rq, p, old_prio);
+
+out_unlock:
+	task_rq_unlock(rq, p, &rf);
+}
+EXPORT_SYMBOL(set_user_nice);
+
+/*
+ * is_nice_reduction - check if nice value is an actual reduction
+ *
+ * Similar to can_nice() but does not perform a capability check.
+ *
+ * @p: task
+ * @nice: nice value
+ */
+static bool is_nice_reduction(const struct task_struct *p, const int nice)
+{
+	/* Convert nice value [19,-20] to rlimit style value [1,40]: */
+	int nice_rlim = nice_to_rlimit(nice);
+
+	return (nice_rlim <= task_rlimit(p, RLIMIT_NICE));
+}
+
+/*
+ * can_nice - check if a task can reduce its nice value
+ * @p: task
+ * @nice: nice value
+ */
+int can_nice(const struct task_struct *p, const int nice)
+{
+	return is_nice_reduction(p, nice) || capable(CAP_SYS_NICE);
+}
+
+#ifdef __ARCH_WANT_SYS_NICE
+
+/*
+ * sys_nice - change the priority of the current process.
+ * @increment: priority increment
+ *
+ * sys_setpriority is a more generic, but much slower function that
+ * does similar things.
+ */
+SYSCALL_DEFINE1(nice, int, increment)
+{
+	long nice, retval;
+
+	/*
+	 * Setpriority might change our priority at the same moment.
+	 * We don't have to worry. Conceptually one call occurs first
+	 * and we have a single winner.
+	 */
+	increment = clamp(increment, -NICE_WIDTH, NICE_WIDTH);
+	nice = task_nice(current) + increment;
+
+	nice = clamp_val(nice, MIN_NICE, MAX_NICE);
+	if (increment < 0 && !can_nice(current, nice))
+		return -EPERM;
+
+	retval = security_task_setnice(current, nice);
+	if (retval)
+		return retval;
+
+	set_user_nice(current, nice);
+	return 0;
+}
+
+#endif
+
+/**
+ * task_prio - return the priority value of a given task.
+ * @p: the task in question.
+ *
+ * Return: The priority value as seen by users in /proc.
+ *
+ * sched policy         return value   kernel prio    user prio/nice
+ *
+ * normal, batch, idle     [0 ... 39]  [100 ... 139]          0/[-20 ... 19]
+ * fifo, rr             [-2 ... -100]     [98 ... 0]  [1 ... 99]
+ * deadline                     -101             -1           0
+ */
+int task_prio(const struct task_struct *p)
+{
+	return p->prio - MAX_RT_PRIO;
+}
+
+/**
+ * idle_cpu - is a given CPU idle currently?
+ * @cpu: the processor in question.
+ *
+ * Return: 1 if the CPU is currently idle. 0 otherwise.
+ */
+int idle_cpu(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	if (rq->curr != rq->idle)
+		return 0;
+
+	if (rq->nr_running)
+		return 0;
+
+#ifdef CONFIG_SMP
+	if (rq->ttwu_pending)
+		return 0;
+#endif
+
+	return 1;
+}
+
+/**
+ * available_idle_cpu - is a given CPU idle for enqueuing work.
+ * @cpu: the CPU in question.
+ *
+ * Return: 1 if the CPU is currently idle. 0 otherwise.
+ */
+int available_idle_cpu(int cpu)
+{
+	if (!idle_cpu(cpu))
+		return 0;
+
+	if (vcpu_is_preempted(cpu))
+		return 0;
+
+	return 1;
+}
+
+/**
+ * idle_task - return the idle task for a given CPU.
+ * @cpu: the processor in question.
+ *
+ * Return: The idle task for the CPU @cpu.
+ */
+struct task_struct *idle_task(int cpu)
+{
+	return cpu_rq(cpu)->idle;
+}
+
+#ifdef CONFIG_SCHED_CORE
+int sched_core_idle_cpu(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	if (sched_core_enabled(rq) && rq->curr == rq->idle)
+		return 1;
+
+	return idle_cpu(cpu);
+}
+
+#endif
+
+#ifdef CONFIG_SMP
+/*
+ * This function computes an effective utilization for the given CPU, to be
+ * used for frequency selection given the linear relation: f = u * f_max.
+ *
+ * The scheduler tracks the following metrics:
+ *
+ *   cpu_util_{cfs,rt,dl,irq}()
+ *   cpu_bw_dl()
+ *
+ * Where the cfs,rt and dl util numbers are tracked with the same metric and
+ * synchronized windows and are thus directly comparable.
+ *
+ * The cfs,rt,dl utilization are the running times measured with rq->clock_task
+ * which excludes things like IRQ and steal-time. These latter are then accrued
+ * in the irq utilization.
+ *
+ * The DL bandwidth number otoh is not a measured metric but a value computed
+ * based on the task model parameters and gives the minimal utilization
+ * required to meet deadlines.
+ */
+unsigned long effective_cpu_util(int cpu, unsigned long util_cfs,
+				 enum cpu_util_type type,
+				 struct task_struct *p)
+{
+	unsigned long dl_util, util, irq, max;
+	struct rq *rq = cpu_rq(cpu);
+
+	max = arch_scale_cpu_capacity(cpu);
+
+	if (!uclamp_is_used() &&
+	    type == FREQUENCY_UTIL && rt_rq_is_runnable(&rq->rt)) {
+		return max;
+	}
+
+	/*
+	 * Early check to see if IRQ/steal time saturates the CPU, can be
+	 * because of inaccuracies in how we track these -- see
+	 * update_irq_load_avg().
+	 */
+	irq = cpu_util_irq(rq);
+	if (unlikely(irq >= max))
+		return max;
+
+	/*
+	 * Because the time spend on RT/DL tasks is visible as 'lost' time to
+	 * CFS tasks and we use the same metric to track the effective
+	 * utilization (PELT windows are synchronized) we can directly add them
+	 * to obtain the CPU's actual utilization.
+	 *
+	 * CFS and RT utilization can be boosted or capped, depending on
+	 * utilization clamp constraints requested by currently RUNNABLE
+	 * tasks.
+	 * When there are no CFS RUNNABLE tasks, clamps are released and
+	 * frequency will be gracefully reduced with the utilization decay.
+	 */
+	util = util_cfs + cpu_util_rt(rq);
+	if (type == FREQUENCY_UTIL)
+		util = uclamp_rq_util_with(rq, util, p);
+
+	dl_util = cpu_util_dl(rq);
+
+	/*
+	 * For frequency selection we do not make cpu_util_dl() a permanent part
+	 * of this sum because we want to use cpu_bw_dl() later on, but we need
+	 * to check if the CFS+RT+DL sum is saturated (ie. no idle time) such
+	 * that we select f_max when there is no idle time.
+	 *
+	 * NOTE: numerical errors or stop class might cause us to not quite hit
+	 * saturation when we should -- something for later.
+	 */
+	if (util + dl_util >= max)
+		return max;
+
+	/*
+	 * OTOH, for energy computation we need the estimated running time, so
+	 * include util_dl and ignore dl_bw.
+	 */
+	if (type == ENERGY_UTIL)
+		util += dl_util;
+
+	/*
+	 * There is still idle time; further improve the number by using the
+	 * irq metric. Because IRQ/steal time is hidden from the task clock we
+	 * need to scale the task numbers:
+	 *
+	 *              max - irq
+	 *   U' = irq + --------- * U
+	 *                 max
+	 */
+	util = scale_irq_capacity(util, irq, max);
+	util += irq;
+
+	/*
+	 * Bandwidth required by DEADLINE must always be granted while, for
+	 * FAIR and RT, we use blocked utilization of IDLE CPUs as a mechanism
+	 * to gracefully reduce the frequency when no tasks show up for longer
+	 * periods of time.
+	 *
+	 * Ideally we would like to set bw_dl as min/guaranteed freq and util +
+	 * bw_dl as requested freq. However, cpufreq is not yet ready for such
+	 * an interface. So, we only do the latter for now.
+	 */
+	if (type == FREQUENCY_UTIL)
+		util += cpu_bw_dl(rq);
+
+	return min(max, util);
+}
+
+unsigned long sched_cpu_util(int cpu)
+{
+	return effective_cpu_util(cpu, cpu_util_cfs(cpu), ENERGY_UTIL, NULL);
+}
+#endif /* CONFIG_SMP */
+
+/**
+ * find_process_by_pid - find a process with a matching PID value.
+ * @pid: the pid in question.
+ *
+ * The task of @pid, if found. %NULL otherwise.
+ */
+static struct task_struct *find_process_by_pid(pid_t pid)
+{
+	return pid ? find_task_by_vpid(pid) : current;
+}
+
+/*
+ * sched_setparam() passes in -1 for its policy, to let the functions
+ * it calls know not to change it.
+ */
+#define SETPARAM_POLICY	-1
+
+static void __setscheduler_params(struct task_struct *p,
+		const struct sched_attr *attr)
+{
+	int policy = attr->sched_policy;
+
+	if (policy == SETPARAM_POLICY)
+		policy = p->policy;
+
+	p->policy = policy;
+
+	if (dl_policy(policy))
+		__setparam_dl(p, attr);
+	else if (fair_policy(policy))
+		p->static_prio = NICE_TO_PRIO(attr->sched_nice);
+
+	/*
+	 * __sched_setscheduler() ensures attr->sched_priority == 0 when
+	 * !rt_policy. Always setting this ensures that things like
+	 * getparam()/getattr() don't report silly values for !rt tasks.
+	 */
+	p->rt_priority = attr->sched_priority;
+	p->normal_prio = normal_prio(p);
+	set_load_weight(p, true);
+}
+
+/*
+ * Check the target process has a UID that matches the current process's:
+ */
+static bool check_same_owner(struct task_struct *p)
+{
+	const struct cred *cred = current_cred(), *pcred;
+	bool match;
+
+	rcu_read_lock();
+	pcred = __task_cred(p);
+	match = (uid_eq(cred->euid, pcred->euid) ||
+		 uid_eq(cred->euid, pcred->uid));
+	rcu_read_unlock();
+	return match;
+}
+
+/*
+ * Allow unprivileged RT tasks to decrease priority.
+ * Only issue a capable test if needed and only once to avoid an audit
+ * event on permitted non-privileged operations:
+ */
+static int user_check_sched_setscheduler(struct task_struct *p,
+					 const struct sched_attr *attr,
+					 int policy, int reset_on_fork)
+{
+	if (fair_policy(policy)) {
+		if (attr->sched_nice < task_nice(p) &&
+		    !is_nice_reduction(p, attr->sched_nice))
+			goto req_priv;
+	}
+
+	if (rt_policy(policy)) {
+		unsigned long rlim_rtprio = task_rlimit(p, RLIMIT_RTPRIO);
+
+		/* Can't set/change the rt policy: */
+		if (policy != p->policy && !rlim_rtprio)
+			goto req_priv;
+
+		/* Can't increase priority: */
+		if (attr->sched_priority > p->rt_priority &&
+		    attr->sched_priority > rlim_rtprio)
+			goto req_priv;
+	}
+
+	/*
+	 * Can't set/change SCHED_DEADLINE policy at all for now
+	 * (safest behavior); in the future we would like to allow
+	 * unprivileged DL tasks to increase their relative deadline
+	 * or reduce their runtime (both ways reducing utilization)
+	 */
+	if (dl_policy(policy))
+		goto req_priv;
+
+	/*
+	 * Treat SCHED_IDLE as nice 20. Only allow a switch to
+	 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
+	 */
+	if (task_has_idle_policy(p) && !idle_policy(policy)) {
+		if (!is_nice_reduction(p, task_nice(p)))
+			goto req_priv;
+	}
+
+	/* Can't change other user's priorities: */
+	if (!check_same_owner(p))
+		goto req_priv;
+
+	/* Normal users shall not reset the sched_reset_on_fork flag: */
+	if (p->sched_reset_on_fork && !reset_on_fork)
+		goto req_priv;
+
+	return 0;
+
+req_priv:
+	if (!capable(CAP_SYS_NICE))
+		return -EPERM;
+
+	return 0;
+}
+
+static int __sched_setscheduler(struct task_struct *p,
+				const struct sched_attr *attr,
+				bool user, bool pi)
+{
+	int oldpolicy = -1, policy = attr->sched_policy;
+	int retval, oldprio, newprio, queued, running;
+	const struct sched_class *prev_class;
+	struct balance_callback *head;
+	struct rq_flags rf;
+	int reset_on_fork;
+	int queue_flags = DEQUEUE_SAVE | DEQUEUE_MOVE | DEQUEUE_NOCLOCK;
+	struct rq *rq;
+	bool cpuset_locked = false;
+
+	/* The pi code expects interrupts enabled */
+	BUG_ON(pi && in_interrupt());
+recheck:
+	/* Double check policy once rq lock held: */
+	if (policy < 0) {
+		reset_on_fork = p->sched_reset_on_fork;
+		policy = oldpolicy = p->policy;
+	} else {
+		reset_on_fork = !!(attr->sched_flags & SCHED_FLAG_RESET_ON_FORK);
+
+		if (!valid_policy(policy))
+			return -EINVAL;
+	}
+
+	if (attr->sched_flags & ~(SCHED_FLAG_ALL | SCHED_FLAG_SUGOV))
+		return -EINVAL;
+
+	/*
+	 * Valid priorities for SCHED_FIFO and SCHED_RR are
+	 * 1..MAX_RT_PRIO-1, valid priority for SCHED_NORMAL,
+	 * SCHED_BATCH and SCHED_IDLE is 0.
+	 */
+	if (attr->sched_priority > MAX_RT_PRIO-1)
+		return -EINVAL;
+	if ((dl_policy(policy) && !__checkparam_dl(attr)) ||
+	    (rt_policy(policy) != (attr->sched_priority != 0)))
+		return -EINVAL;
+
+	if (user) {
+		retval = user_check_sched_setscheduler(p, attr, policy, reset_on_fork);
+		if (retval)
+			return retval;
+
+		if (attr->sched_flags & SCHED_FLAG_SUGOV)
+			return -EINVAL;
+
+		retval = security_task_setscheduler(p);
+		if (retval)
+			return retval;
+	}
+
+	/* Update task specific "requested" clamps */
+	if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP) {
+		retval = uclamp_validate(p, attr);
+		if (retval)
+			return retval;
+	}
+
+	/*
+	 * SCHED_DEADLINE bandwidth accounting relies on stable cpusets
+	 * information.
+	 */
+	if (dl_policy(policy) || dl_policy(p->policy)) {
+		cpuset_locked = true;
+		cpuset_lock();
+	}
+
+	/*
+	 * Make sure no PI-waiters arrive (or leave) while we are
+	 * changing the priority of the task:
+	 *
+	 * To be able to change p->policy safely, the appropriate
+	 * runqueue lock must be held.
+	 */
+	rq = task_rq_lock(p, &rf);
+	update_rq_clock(rq);
+
+	/*
+	 * Changing the policy of the stop threads its a very bad idea:
+	 */
+	if (p == rq->stop) {
+		retval = -EINVAL;
+		goto unlock;
+	}
+
+	/*
+	 * If not changing anything there's no need to proceed further,
+	 * but store a possible modification of reset_on_fork.
+	 */
+	if (unlikely(policy == p->policy)) {
+		if (fair_policy(policy) && attr->sched_nice != task_nice(p))
+			goto change;
+		if (rt_policy(policy) && attr->sched_priority != p->rt_priority)
+			goto change;
+		if (dl_policy(policy) && dl_param_changed(p, attr))
+			goto change;
+		if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP)
+			goto change;
+
+		p->sched_reset_on_fork = reset_on_fork;
+		retval = 0;
+		goto unlock;
+	}
+change:
+
+	if (user) {
+#ifdef CONFIG_RT_GROUP_SCHED
+		/*
+		 * Do not allow realtime tasks into groups that have no runtime
+		 * assigned.
+		 */
+		if (rt_bandwidth_enabled() && rt_policy(policy) &&
+				task_group(p)->rt_bandwidth.rt_runtime == 0 &&
+				!task_group_is_autogroup(task_group(p))) {
+			retval = -EPERM;
+			goto unlock;
+		}
+#endif
+#ifdef CONFIG_SMP
+		if (dl_bandwidth_enabled() && dl_policy(policy) &&
+				!(attr->sched_flags & SCHED_FLAG_SUGOV)) {
+			cpumask_t *span = rq->rd->span;
+
+			/*
+			 * Don't allow tasks with an affinity mask smaller than
+			 * the entire root_domain to become SCHED_DEADLINE. We
+			 * will also fail if there's no bandwidth available.
+			 */
+			if (!cpumask_subset(span, p->cpus_ptr) ||
+			    rq->rd->dl_bw.bw == 0) {
+				retval = -EPERM;
+				goto unlock;
+			}
+		}
+#endif
+	}
+
+	/* Re-check policy now with rq lock held: */
+	if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
+		policy = oldpolicy = -1;
+		task_rq_unlock(rq, p, &rf);
+		if (cpuset_locked)
+			cpuset_unlock();
+		goto recheck;
+	}
+
+	/*
+	 * If setscheduling to SCHED_DEADLINE (or changing the parameters
+	 * of a SCHED_DEADLINE task) we need to check if enough bandwidth
+	 * is available.
+	 */
+	if ((dl_policy(policy) || dl_task(p)) && sched_dl_overflow(p, policy, attr)) {
+		retval = -EBUSY;
+		goto unlock;
+	}
+
+	p->sched_reset_on_fork = reset_on_fork;
+	oldprio = p->prio;
+
+	newprio = __normal_prio(policy, attr->sched_priority, attr->sched_nice);
+	if (pi) {
+		/*
+		 * Take priority boosted tasks into account. If the new
+		 * effective priority is unchanged, we just store the new
+		 * normal parameters and do not touch the scheduler class and
+		 * the runqueue. This will be done when the task deboost
+		 * itself.
+		 */
+		newprio = rt_effective_prio(p, newprio);
+		if (newprio == oldprio)
+			queue_flags &= ~DEQUEUE_MOVE;
+	}
+
+	queued = task_on_rq_queued(p);
+	running = task_current(rq, p);
+	if (queued)
+		dequeue_task(rq, p, queue_flags);
+	if (running)
+		put_prev_task(rq, p);
+
+	prev_class = p->sched_class;
+
+	if (!(attr->sched_flags & SCHED_FLAG_KEEP_PARAMS)) {
+		__setscheduler_params(p, attr);
+		__setscheduler_prio(p, newprio);
+	}
+	__setscheduler_uclamp(p, attr);
+
+	if (queued) {
+		/*
+		 * We enqueue to tail when the priority of a task is
+		 * increased (user space view).
+		 */
+		if (oldprio < p->prio)
+			queue_flags |= ENQUEUE_HEAD;
+
+		enqueue_task(rq, p, queue_flags);
+	}
+	if (running)
+		set_next_task(rq, p);
+
+	check_class_changed(rq, p, prev_class, oldprio);
+
+	/* Avoid rq from going away on us: */
+	preempt_disable();
+	head = splice_balance_callbacks(rq);
+	task_rq_unlock(rq, p, &rf);
+
+	if (pi) {
+		if (cpuset_locked)
+			cpuset_unlock();
+		rt_mutex_adjust_pi(p);
+	}
+
+	/* Run balance callbacks after we've adjusted the PI chain: */
+	balance_callbacks(rq, head);
+	preempt_enable();
+
+	return 0;
+
+unlock:
+	task_rq_unlock(rq, p, &rf);
+	if (cpuset_locked)
+		cpuset_unlock();
+	return retval;
+}
+
+static int _sched_setscheduler(struct task_struct *p, int policy,
+			       const struct sched_param *param, bool check)
+{
+	struct sched_attr attr = {
+		.sched_policy   = policy,
+		.sched_priority = param->sched_priority,
+		.sched_nice	= PRIO_TO_NICE(p->static_prio),
+	};
+
+	/* Fixup the legacy SCHED_RESET_ON_FORK hack. */
+	if ((policy != SETPARAM_POLICY) && (policy & SCHED_RESET_ON_FORK)) {
+		attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;
+		policy &= ~SCHED_RESET_ON_FORK;
+		attr.sched_policy = policy;
+	}
+
+	return __sched_setscheduler(p, &attr, check, true);
+}
+/**
+ * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
+ * @p: the task in question.
+ * @policy: new policy.
+ * @param: structure containing the new RT priority.
+ *
+ * Use sched_set_fifo(), read its comment.
+ *
+ * Return: 0 on success. An error code otherwise.
+ *
+ * NOTE that the task may be already dead.
+ */
+int sched_setscheduler(struct task_struct *p, int policy,
+		       const struct sched_param *param)
+{
+	return _sched_setscheduler(p, policy, param, true);
+}
+
+int sched_setattr(struct task_struct *p, const struct sched_attr *attr)
+{
+	return __sched_setscheduler(p, attr, true, true);
+}
+
+int sched_setattr_nocheck(struct task_struct *p, const struct sched_attr *attr)
+{
+	return __sched_setscheduler(p, attr, false, true);
+}
+EXPORT_SYMBOL_GPL(sched_setattr_nocheck);
+
+/**
+ * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
+ * @p: the task in question.
+ * @policy: new policy.
+ * @param: structure containing the new RT priority.
+ *
+ * Just like sched_setscheduler, only don't bother checking if the
+ * current context has permission.  For example, this is needed in
+ * stop_machine(): we create temporary high priority worker threads,
+ * but our caller might not have that capability.
+ *
+ * Return: 0 on success. An error code otherwise.
+ */
+int sched_setscheduler_nocheck(struct task_struct *p, int policy,
+			       const struct sched_param *param)
+{
+	return _sched_setscheduler(p, policy, param, false);
+}
+
+/*
+ * SCHED_FIFO is a broken scheduler model; that is, it is fundamentally
+ * incapable of resource management, which is the one thing an OS really should
+ * be doing.
+ *
+ * This is of course the reason it is limited to privileged users only.
+ *
+ * Worse still; it is fundamentally impossible to compose static priority
+ * workloads. You cannot take two correctly working static prio workloads
+ * and smash them together and still expect them to work.
+ *
+ * For this reason 'all' FIFO tasks the kernel creates are basically at:
+ *
+ *   MAX_RT_PRIO / 2
+ *
+ * The administrator _MUST_ configure the system, the kernel simply doesn't
+ * know enough information to make a sensible choice.
+ */
+void sched_set_fifo(struct task_struct *p)
+{
+	struct sched_param sp = { .sched_priority = MAX_RT_PRIO / 2 };
+	WARN_ON_ONCE(sched_setscheduler_nocheck(p, SCHED_FIFO, &sp) != 0);
+}
+EXPORT_SYMBOL_GPL(sched_set_fifo);
+
+/*
+ * For when you don't much care about FIFO, but want to be above SCHED_NORMAL.
+ */
+void sched_set_fifo_low(struct task_struct *p)
+{
+	struct sched_param sp = { .sched_priority = 1 };
+	WARN_ON_ONCE(sched_setscheduler_nocheck(p, SCHED_FIFO, &sp) != 0);
+}
+EXPORT_SYMBOL_GPL(sched_set_fifo_low);
+
+void sched_set_normal(struct task_struct *p, int nice)
+{
+	struct sched_attr attr = {
+		.sched_policy = SCHED_NORMAL,
+		.sched_nice = nice,
+	};
+	WARN_ON_ONCE(sched_setattr_nocheck(p, &attr) != 0);
+}
+EXPORT_SYMBOL_GPL(sched_set_normal);
+
+static int
+do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
+{
+	struct sched_param lparam;
+	struct task_struct *p;
+	int retval;
+
+	if (!param || pid < 0)
+		return -EINVAL;
+	if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
+		return -EFAULT;
+
+	rcu_read_lock();
+	retval = -ESRCH;
+	p = find_process_by_pid(pid);
+	if (likely(p))
+		get_task_struct(p);
+	rcu_read_unlock();
+
+	if (likely(p)) {
+		retval = sched_setscheduler(p, policy, &lparam);
+		put_task_struct(p);
+	}
+
+	return retval;
+}
+
+/*
+ * Mimics kernel/events/core.c perf_copy_attr().
+ */
+static int sched_copy_attr(struct sched_attr __user *uattr, struct sched_attr *attr)
+{
+	u32 size;
+	int ret;
+
+	/* Zero the full structure, so that a short copy will be nice: */
+	memset(attr, 0, sizeof(*attr));
+
+	ret = get_user(size, &uattr->size);
+	if (ret)
+		return ret;
+
+	/* ABI compatibility quirk: */
+	if (!size)
+		size = SCHED_ATTR_SIZE_VER0;
+	if (size < SCHED_ATTR_SIZE_VER0 || size > PAGE_SIZE)
+		goto err_size;
+
+	ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
+	if (ret) {
+		if (ret == -E2BIG)
+			goto err_size;
+		return ret;
+	}
+
+	if ((attr->sched_flags & SCHED_FLAG_UTIL_CLAMP) &&
+	    size < SCHED_ATTR_SIZE_VER1)
+		return -EINVAL;
+
+	/*
+	 * XXX: Do we want to be lenient like existing syscalls; or do we want
+	 * to be strict and return an error on out-of-bounds values?
+	 */
+	attr->sched_nice = clamp(attr->sched_nice, MIN_NICE, MAX_NICE);
+
+	return 0;
+
+err_size:
+	put_user(sizeof(*attr), &uattr->size);
+	return -E2BIG;
+}
+
+static void get_params(struct task_struct *p, struct sched_attr *attr)
+{
+	if (task_has_dl_policy(p))
+		__getparam_dl(p, attr);
+	else if (task_has_rt_policy(p))
+		attr->sched_priority = p->rt_priority;
+	else
+		attr->sched_nice = task_nice(p);
+}
+
+/**
+ * sys_sched_setscheduler - set/change the scheduler policy and RT priority
+ * @pid: the pid in question.
+ * @policy: new policy.
+ * @param: structure containing the new RT priority.
+ *
+ * Return: 0 on success. An error code otherwise.
+ */
+SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, struct sched_param __user *, param)
+{
+	if (policy < 0)
+		return -EINVAL;
+
+	return do_sched_setscheduler(pid, policy, param);
+}
+
+/**
+ * sys_sched_setparam - set/change the RT priority of a thread
+ * @pid: the pid in question.
+ * @param: structure containing the new RT priority.
+ *
+ * Return: 0 on success. An error code otherwise.
+ */
+SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
+{
+	return do_sched_setscheduler(pid, SETPARAM_POLICY, param);
+}
+
+/**
+ * sys_sched_setattr - same as above, but with extended sched_attr
+ * @pid: the pid in question.
+ * @uattr: structure containing the extended parameters.
+ * @flags: for future extension.
+ */
+SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr,
+			       unsigned int, flags)
+{
+	struct sched_attr attr;
+	struct task_struct *p;
+	int retval;
+
+	if (!uattr || pid < 0 || flags)
+		return -EINVAL;
+
+	retval = sched_copy_attr(uattr, &attr);
+	if (retval)
+		return retval;
+
+	if ((int)attr.sched_policy < 0)
+		return -EINVAL;
+	if (attr.sched_flags & SCHED_FLAG_KEEP_POLICY)
+		attr.sched_policy = SETPARAM_POLICY;
+
+	rcu_read_lock();
+	retval = -ESRCH;
+	p = find_process_by_pid(pid);
+	if (likely(p))
+		get_task_struct(p);
+	rcu_read_unlock();
+
+	if (likely(p)) {
+		if (attr.sched_flags & SCHED_FLAG_KEEP_PARAMS)
+			get_params(p, &attr);
+		retval = sched_setattr(p, &attr);
+		put_task_struct(p);
+	}
+
+	return retval;
+}
+
+/**
+ * sys_sched_getscheduler - get the policy (scheduling class) of a thread
+ * @pid: the pid in question.
+ *
+ * Return: On success, the policy of the thread. Otherwise, a negative error
+ * code.
+ */
+SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
+{
+	struct task_struct *p;
+	int retval;
+
+	if (pid < 0)
+		return -EINVAL;
+
+	retval = -ESRCH;
+	rcu_read_lock();
+	p = find_process_by_pid(pid);
+	if (p) {
+		retval = security_task_getscheduler(p);
+		if (!retval)
+			retval = p->policy
+				| (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0);
+	}
+	rcu_read_unlock();
+	return retval;
+}
+
+/**
+ * sys_sched_getparam - get the RT priority of a thread
+ * @pid: the pid in question.
+ * @param: structure containing the RT priority.
+ *
+ * Return: On success, 0 and the RT priority is in @param. Otherwise, an error
+ * code.
+ */
+SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
+{
+	struct sched_param lp = { .sched_priority = 0 };
+	struct task_struct *p;
+	int retval;
+
+	if (!param || pid < 0)
+		return -EINVAL;
+
+	rcu_read_lock();
+	p = find_process_by_pid(pid);
+	retval = -ESRCH;
+	if (!p)
+		goto out_unlock;
+
+	retval = security_task_getscheduler(p);
+	if (retval)
+		goto out_unlock;
+
+	if (task_has_rt_policy(p))
+		lp.sched_priority = p->rt_priority;
+	rcu_read_unlock();
+
+	/*
+	 * This one might sleep, we cannot do it with a spinlock held ...
+	 */
+	retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
+
+	return retval;
+
+out_unlock:
+	rcu_read_unlock();
+	return retval;
+}
+
+/*
+ * Copy the kernel size attribute structure (which might be larger
+ * than what user-space knows about) to user-space.
+ *
+ * Note that all cases are valid: user-space buffer can be larger or
+ * smaller than the kernel-space buffer. The usual case is that both
+ * have the same size.
+ */
+static int
+sched_attr_copy_to_user(struct sched_attr __user *uattr,
+			struct sched_attr *kattr,
+			unsigned int usize)
+{
+	unsigned int ksize = sizeof(*kattr);
+
+	if (!access_ok(uattr, usize))
+		return -EFAULT;
+
+	/*
+	 * sched_getattr() ABI forwards and backwards compatibility:
+	 *
+	 * If usize == ksize then we just copy everything to user-space and all is good.
+	 *
+	 * If usize < ksize then we only copy as much as user-space has space for,
+	 * this keeps ABI compatibility as well. We skip the rest.
+	 *
+	 * If usize > ksize then user-space is using a newer version of the ABI,
+	 * which part the kernel doesn't know about. Just ignore it - tooling can
+	 * detect the kernel's knowledge of attributes from the attr->size value
+	 * which is set to ksize in this case.
+	 */
+	kattr->size = min(usize, ksize);
+
+	if (copy_to_user(uattr, kattr, kattr->size))
+		return -EFAULT;
+
+	return 0;
+}
+
+/**
+ * sys_sched_getattr - similar to sched_getparam, but with sched_attr
+ * @pid: the pid in question.
+ * @uattr: structure containing the extended parameters.
+ * @usize: sizeof(attr) for fwd/bwd comp.
+ * @flags: for future extension.
+ */
+SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr,
+		unsigned int, usize, unsigned int, flags)
+{
+	struct sched_attr kattr = { };
+	struct task_struct *p;
+	int retval;
+
+	if (!uattr || pid < 0 || usize > PAGE_SIZE ||
+	    usize < SCHED_ATTR_SIZE_VER0 || flags)
+		return -EINVAL;
+
+	rcu_read_lock();
+	p = find_process_by_pid(pid);
+	retval = -ESRCH;
+	if (!p)
+		goto out_unlock;
+
+	retval = security_task_getscheduler(p);
+	if (retval)
+		goto out_unlock;
+
+	kattr.sched_policy = p->policy;
+	if (p->sched_reset_on_fork)
+		kattr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;
+	get_params(p, &kattr);
+	kattr.sched_flags &= SCHED_FLAG_ALL;
+
+#ifdef CONFIG_UCLAMP_TASK
+	/*
+	 * This could race with another potential updater, but this is fine
+	 * because it'll correctly read the old or the new value. We don't need
+	 * to guarantee who wins the race as long as it doesn't return garbage.
+	 */
+	kattr.sched_util_min = p->uclamp_req[UCLAMP_MIN].value;
+	kattr.sched_util_max = p->uclamp_req[UCLAMP_MAX].value;
+#endif
+
+	rcu_read_unlock();
+
+	return sched_attr_copy_to_user(uattr, &kattr, usize);
+
+out_unlock:
+	rcu_read_unlock();
+	return retval;
+}
+
+#ifdef CONFIG_SMP
+int dl_task_check_affinity(struct task_struct *p, const struct cpumask *mask)
+{
+	int ret = 0;
+
+	/*
+	 * If the task isn't a deadline task or admission control is
+	 * disabled then we don't care about affinity changes.
+	 */
+	if (!task_has_dl_policy(p) || !dl_bandwidth_enabled())
+		return 0;
+
+	/*
+	 * Since bandwidth control happens on root_domain basis,
+	 * if admission test is enabled, we only admit -deadline
+	 * tasks allowed to run on all the CPUs in the task's
+	 * root_domain.
+	 */
+	rcu_read_lock();
+	if (!cpumask_subset(task_rq(p)->rd->span, mask))
+		ret = -EBUSY;
+	rcu_read_unlock();
+	return ret;
+}
+#endif
+
+static int
+__sched_setaffinity(struct task_struct *p, struct affinity_context *ctx)
+{
+	int retval;
+	cpumask_var_t cpus_allowed, new_mask;
+
+	if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL))
+		return -ENOMEM;
+
+	if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
+		retval = -ENOMEM;
+		goto out_free_cpus_allowed;
+	}
+
+	cpuset_cpus_allowed(p, cpus_allowed);
+	cpumask_and(new_mask, ctx->new_mask, cpus_allowed);
+
+	ctx->new_mask = new_mask;
+	ctx->flags |= SCA_CHECK;
+
+	retval = dl_task_check_affinity(p, new_mask);
+	if (retval)
+		goto out_free_new_mask;
+
+	retval = __set_cpus_allowed_ptr(p, ctx);
+	if (retval)
+		goto out_free_new_mask;
+
+	cpuset_cpus_allowed(p, cpus_allowed);
+	if (!cpumask_subset(new_mask, cpus_allowed)) {
+		/*
+		 * We must have raced with a concurrent cpuset update.
+		 * Just reset the cpumask to the cpuset's cpus_allowed.
+		 */
+		cpumask_copy(new_mask, cpus_allowed);
+
+		/*
+		 * If SCA_USER is set, a 2nd call to __set_cpus_allowed_ptr()
+		 * will restore the previous user_cpus_ptr value.
+		 *
+		 * In the unlikely event a previous user_cpus_ptr exists,
+		 * we need to further restrict the mask to what is allowed
+		 * by that old user_cpus_ptr.
+		 */
+		if (unlikely((ctx->flags & SCA_USER) && ctx->user_mask)) {
+			bool empty = !cpumask_and(new_mask, new_mask,
+						  ctx->user_mask);
+
+			if (WARN_ON_ONCE(empty))
+				cpumask_copy(new_mask, cpus_allowed);
+		}
+		__set_cpus_allowed_ptr(p, ctx);
+		retval = -EINVAL;
+	}
+
+out_free_new_mask:
+	free_cpumask_var(new_mask);
+out_free_cpus_allowed:
+	free_cpumask_var(cpus_allowed);
+	return retval;
+}
+
+long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
+{
+	struct affinity_context ac;
+	struct cpumask *user_mask;
+	struct task_struct *p;
+	int retval;
+
+	rcu_read_lock();
+
+	p = find_process_by_pid(pid);
+	if (!p) {
+		rcu_read_unlock();
+		return -ESRCH;
+	}
+
+	/* Prevent p going away */
+	get_task_struct(p);
+	rcu_read_unlock();
+
+	if (p->flags & PF_NO_SETAFFINITY) {
+		retval = -EINVAL;
+		goto out_put_task;
+	}
+
+	if (!check_same_owner(p)) {
+		rcu_read_lock();
+		if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
+			rcu_read_unlock();
+			retval = -EPERM;
+			goto out_put_task;
+		}
+		rcu_read_unlock();
+	}
+
+	retval = security_task_setscheduler(p);
+	if (retval)
+		goto out_put_task;
+
+	/*
+	 * With non-SMP configs, user_cpus_ptr/user_mask isn't used and
+	 * alloc_user_cpus_ptr() returns NULL.
+	 */
+	user_mask = alloc_user_cpus_ptr(NUMA_NO_NODE);
+	if (user_mask) {
+		cpumask_copy(user_mask, in_mask);
+	} else if (IS_ENABLED(CONFIG_SMP)) {
+		retval = -ENOMEM;
+		goto out_put_task;
+	}
+
+	ac = (struct affinity_context){
+		.new_mask  = in_mask,
+		.user_mask = user_mask,
+		.flags     = SCA_USER,
+	};
+
+	retval = __sched_setaffinity(p, &ac);
+	kfree(ac.user_mask);
+
+out_put_task:
+	put_task_struct(p);
+	return retval;
+}
+
+static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
+			     struct cpumask *new_mask)
+{
+	if (len < cpumask_size())
+		cpumask_clear(new_mask);
+	else if (len > cpumask_size())
+		len = cpumask_size();
+
+	return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
+}
+
+/**
+ * sys_sched_setaffinity - set the CPU affinity of a process
+ * @pid: pid of the process
+ * @len: length in bytes of the bitmask pointed to by user_mask_ptr
+ * @user_mask_ptr: user-space pointer to the new CPU mask
+ *
+ * Return: 0 on success. An error code otherwise.
+ */
+SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
+		unsigned long __user *, user_mask_ptr)
+{
+	cpumask_var_t new_mask;
+	int retval;
+
+	if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
+		return -ENOMEM;
+
+	retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
+	if (retval == 0)
+		retval = sched_setaffinity(pid, new_mask);
+	free_cpumask_var(new_mask);
+	return retval;
+}
+
+long sched_getaffinity(pid_t pid, struct cpumask *mask)
+{
+	struct task_struct *p;
+	unsigned long flags;
+	int retval;
+
+	rcu_read_lock();
+
+	retval = -ESRCH;
+	p = find_process_by_pid(pid);
+	if (!p)
+		goto out_unlock;
+
+	retval = security_task_getscheduler(p);
+	if (retval)
+		goto out_unlock;
+
+	raw_spin_lock_irqsave(&p->pi_lock, flags);
+	cpumask_and(mask, &p->cpus_mask, cpu_active_mask);
+	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+
+out_unlock:
+	rcu_read_unlock();
+
+	return retval;
+}
+
+/**
+ * sys_sched_getaffinity - get the CPU affinity of a process
+ * @pid: pid of the process
+ * @len: length in bytes of the bitmask pointed to by user_mask_ptr
+ * @user_mask_ptr: user-space pointer to hold the current CPU mask
+ *
+ * Return: size of CPU mask copied to user_mask_ptr on success. An
+ * error code otherwise.
+ */
+SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
+		unsigned long __user *, user_mask_ptr)
+{
+	int ret;
+	cpumask_var_t mask;
+
+	if ((len * BITS_PER_BYTE) < nr_cpu_ids)
+		return -EINVAL;
+	if (len & (sizeof(unsigned long)-1))
+		return -EINVAL;
+
+	if (!zalloc_cpumask_var(&mask, GFP_KERNEL))
+		return -ENOMEM;
+
+	ret = sched_getaffinity(pid, mask);
+	if (ret == 0) {
+		unsigned int retlen = min(len, cpumask_size());
+
+		if (copy_to_user(user_mask_ptr, cpumask_bits(mask), retlen))
+			ret = -EFAULT;
+		else
+			ret = retlen;
+	}
+	free_cpumask_var(mask);
+
+	return ret;
+}
+
+static void do_sched_yield(void)
+{
+	struct rq_flags rf;
+	struct rq *rq;
+
+	rq = this_rq_lock_irq(&rf);
+
+	schedstat_inc(rq->yld_count);
+	current->sched_class->yield_task(rq);
+
+	preempt_disable();
+	rq_unlock_irq(rq, &rf);
+	sched_preempt_enable_no_resched();
+
+	schedule();
+}
+
+/**
+ * sys_sched_yield - yield the current processor to other threads.
+ *
+ * This function yields the current CPU to other tasks. If there are no
+ * other threads running on this CPU then this function will return.
+ *
+ * Return: 0.
+ */
+SYSCALL_DEFINE0(sched_yield)
+{
+	do_sched_yield();
+	return 0;
+}
+
+#if !defined(CONFIG_PREEMPTION) || defined(CONFIG_PREEMPT_DYNAMIC)
+int __sched __cond_resched(void)
+{
+	if (should_resched(0)) {
+		preempt_schedule_common();
+		return 1;
+	}
+	/*
+	 * In preemptible kernels, ->rcu_read_lock_nesting tells the tick
+	 * whether the current CPU is in an RCU read-side critical section,
+	 * so the tick can report quiescent states even for CPUs looping
+	 * in kernel context.  In contrast, in non-preemptible kernels,
+	 * RCU readers leave no in-memory hints, which means that CPU-bound
+	 * processes executing in kernel context might never report an
+	 * RCU quiescent state.  Therefore, the following code causes
+	 * cond_resched() to report a quiescent state, but only when RCU
+	 * is in urgent need of one.
+	 */
+#ifndef CONFIG_PREEMPT_RCU
+	rcu_all_qs();
+#endif
+	return 0;
+}
+EXPORT_SYMBOL(__cond_resched);
+#endif
+
+#ifdef CONFIG_PREEMPT_DYNAMIC
+#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL)
+#define cond_resched_dynamic_enabled	__cond_resched
+#define cond_resched_dynamic_disabled	((void *)&__static_call_return0)
+DEFINE_STATIC_CALL_RET0(cond_resched, __cond_resched);
+EXPORT_STATIC_CALL_TRAMP(cond_resched);
+
+#define might_resched_dynamic_enabled	__cond_resched
+#define might_resched_dynamic_disabled	((void *)&__static_call_return0)
+DEFINE_STATIC_CALL_RET0(might_resched, __cond_resched);
+EXPORT_STATIC_CALL_TRAMP(might_resched);
+#elif defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY)
+static DEFINE_STATIC_KEY_FALSE(sk_dynamic_cond_resched);
+int __sched dynamic_cond_resched(void)
+{
+	klp_sched_try_switch();
+	if (!static_branch_unlikely(&sk_dynamic_cond_resched))
+		return 0;
+	return __cond_resched();
+}
+EXPORT_SYMBOL(dynamic_cond_resched);
+
+static DEFINE_STATIC_KEY_FALSE(sk_dynamic_might_resched);
+int __sched dynamic_might_resched(void)
+{
+	if (!static_branch_unlikely(&sk_dynamic_might_resched))
+		return 0;
+	return __cond_resched();
+}
+EXPORT_SYMBOL(dynamic_might_resched);
+#endif
+#endif
+
+/*
+ * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
+ * call schedule, and on return reacquire the lock.
+ *
+ * This works OK both with and without CONFIG_PREEMPTION. We do strange low-level
+ * operations here to prevent schedule() from being called twice (once via
+ * spin_unlock(), once by hand).
+ */
+int __cond_resched_lock(spinlock_t *lock)
+{
+	int resched = should_resched(PREEMPT_LOCK_OFFSET);
+	int ret = 0;
+
+	lockdep_assert_held(lock);
+
+	if (spin_needbreak(lock) || resched) {
+		spin_unlock(lock);
+		if (!_cond_resched())
+			cpu_relax();
+		ret = 1;
+		spin_lock(lock);
+	}
+	return ret;
+}
+EXPORT_SYMBOL(__cond_resched_lock);
+
+int __cond_resched_rwlock_read(rwlock_t *lock)
+{
+	int resched = should_resched(PREEMPT_LOCK_OFFSET);
+	int ret = 0;
+
+	lockdep_assert_held_read(lock);
+
+	if (rwlock_needbreak(lock) || resched) {
+		read_unlock(lock);
+		if (!_cond_resched())
+			cpu_relax();
+		ret = 1;
+		read_lock(lock);
+	}
+	return ret;
+}
+EXPORT_SYMBOL(__cond_resched_rwlock_read);
+
+int __cond_resched_rwlock_write(rwlock_t *lock)
+{
+	int resched = should_resched(PREEMPT_LOCK_OFFSET);
+	int ret = 0;
+
+	lockdep_assert_held_write(lock);
+
+	if (rwlock_needbreak(lock) || resched) {
+		write_unlock(lock);
+		if (!_cond_resched())
+			cpu_relax();
+		ret = 1;
+		write_lock(lock);
+	}
+	return ret;
+}
+EXPORT_SYMBOL(__cond_resched_rwlock_write);
+
+#ifdef CONFIG_PREEMPT_DYNAMIC
+
+#ifdef CONFIG_GENERIC_ENTRY
+#include <linux/entry-common.h>
+#endif
+
+/*
+ * SC:cond_resched
+ * SC:might_resched
+ * SC:preempt_schedule
+ * SC:preempt_schedule_notrace
+ * SC:irqentry_exit_cond_resched
+ *
+ *
+ * NONE:
+ *   cond_resched               <- __cond_resched
+ *   might_resched              <- RET0
+ *   preempt_schedule           <- NOP
+ *   preempt_schedule_notrace   <- NOP
+ *   irqentry_exit_cond_resched <- NOP
+ *
+ * VOLUNTARY:
+ *   cond_resched               <- __cond_resched
+ *   might_resched              <- __cond_resched
+ *   preempt_schedule           <- NOP
+ *   preempt_schedule_notrace   <- NOP
+ *   irqentry_exit_cond_resched <- NOP
+ *
+ * FULL:
+ *   cond_resched               <- RET0
+ *   might_resched              <- RET0
+ *   preempt_schedule           <- preempt_schedule
+ *   preempt_schedule_notrace   <- preempt_schedule_notrace
+ *   irqentry_exit_cond_resched <- irqentry_exit_cond_resched
+ */
+
+enum {
+	preempt_dynamic_undefined = -1,
+	preempt_dynamic_none,
+	preempt_dynamic_voluntary,
+	preempt_dynamic_full,
+};
+
+int preempt_dynamic_mode = preempt_dynamic_undefined;
+
+int sched_dynamic_mode(const char *str)
+{
+	if (!strcmp(str, "none"))
+		return preempt_dynamic_none;
+
+	if (!strcmp(str, "voluntary"))
+		return preempt_dynamic_voluntary;
+
+	if (!strcmp(str, "full"))
+		return preempt_dynamic_full;
+
+	return -EINVAL;
+}
+
+#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL)
+#define preempt_dynamic_enable(f)	static_call_update(f, f##_dynamic_enabled)
+#define preempt_dynamic_disable(f)	static_call_update(f, f##_dynamic_disabled)
+#elif defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY)
+#define preempt_dynamic_enable(f)	static_key_enable(&sk_dynamic_##f.key)
+#define preempt_dynamic_disable(f)	static_key_disable(&sk_dynamic_##f.key)
+#else
+#error "Unsupported PREEMPT_DYNAMIC mechanism"
+#endif
+
+static DEFINE_MUTEX(sched_dynamic_mutex);
+static bool klp_override;
+
+static void __sched_dynamic_update(int mode)
+{
+	/*
+	 * Avoid {NONE,VOLUNTARY} -> FULL transitions from ever ending up in
+	 * the ZERO state, which is invalid.
+	 */
+	if (!klp_override)
+		preempt_dynamic_enable(cond_resched);
+	preempt_dynamic_enable(might_resched);
+	preempt_dynamic_enable(preempt_schedule);
+	preempt_dynamic_enable(preempt_schedule_notrace);
+	preempt_dynamic_enable(irqentry_exit_cond_resched);
+
+	switch (mode) {
+	case preempt_dynamic_none:
+		if (!klp_override)
+			preempt_dynamic_enable(cond_resched);
+		preempt_dynamic_disable(might_resched);
+		preempt_dynamic_disable(preempt_schedule);
+		preempt_dynamic_disable(preempt_schedule_notrace);
+		preempt_dynamic_disable(irqentry_exit_cond_resched);
+		if (mode != preempt_dynamic_mode)
+			pr_info("Dynamic Preempt: none\n");
+		break;
+
+	case preempt_dynamic_voluntary:
+		if (!klp_override)
+			preempt_dynamic_enable(cond_resched);
+		preempt_dynamic_enable(might_resched);
+		preempt_dynamic_disable(preempt_schedule);
+		preempt_dynamic_disable(preempt_schedule_notrace);
+		preempt_dynamic_disable(irqentry_exit_cond_resched);
+		if (mode != preempt_dynamic_mode)
+			pr_info("Dynamic Preempt: voluntary\n");
+		break;
+
+	case preempt_dynamic_full:
+		if (!klp_override)
+			preempt_dynamic_disable(cond_resched);
+		preempt_dynamic_disable(might_resched);
+		preempt_dynamic_enable(preempt_schedule);
+		preempt_dynamic_enable(preempt_schedule_notrace);
+		preempt_dynamic_enable(irqentry_exit_cond_resched);
+		if (mode != preempt_dynamic_mode)
+			pr_info("Dynamic Preempt: full\n");
+		break;
+	}
+
+	preempt_dynamic_mode = mode;
+}
+
+void sched_dynamic_update(int mode)
+{
+	mutex_lock(&sched_dynamic_mutex);
+	__sched_dynamic_update(mode);
+	mutex_unlock(&sched_dynamic_mutex);
+}
+
+#ifdef CONFIG_HAVE_PREEMPT_DYNAMIC_CALL
+
+static int klp_cond_resched(void)
+{
+	__klp_sched_try_switch();
+	return __cond_resched();
+}
+
+void sched_dynamic_klp_enable(void)
+{
+	mutex_lock(&sched_dynamic_mutex);
+
+	klp_override = true;
+	static_call_update(cond_resched, klp_cond_resched);
+
+	mutex_unlock(&sched_dynamic_mutex);
+}
+
+void sched_dynamic_klp_disable(void)
+{
+	mutex_lock(&sched_dynamic_mutex);
+
+	klp_override = false;
+	__sched_dynamic_update(preempt_dynamic_mode);
+
+	mutex_unlock(&sched_dynamic_mutex);
+}
+
+#endif /* CONFIG_HAVE_PREEMPT_DYNAMIC_CALL */
+
+static int __init setup_preempt_mode(char *str)
+{
+	int mode = sched_dynamic_mode(str);
+	if (mode < 0) {
+		pr_warn("Dynamic Preempt: unsupported mode: %s\n", str);
+		return 0;
+	}
+
+	sched_dynamic_update(mode);
+	return 1;
+}
+__setup("preempt=", setup_preempt_mode);
+
+static void __init preempt_dynamic_init(void)
+{
+	if (preempt_dynamic_mode == preempt_dynamic_undefined) {
+		if (IS_ENABLED(CONFIG_PREEMPT_NONE)) {
+			sched_dynamic_update(preempt_dynamic_none);
+		} else if (IS_ENABLED(CONFIG_PREEMPT_VOLUNTARY)) {
+			sched_dynamic_update(preempt_dynamic_voluntary);
+		} else {
+			/* Default static call setting, nothing to do */
+			WARN_ON_ONCE(!IS_ENABLED(CONFIG_PREEMPT));
+			preempt_dynamic_mode = preempt_dynamic_full;
+			pr_info("Dynamic Preempt: full\n");
+		}
+	}
+}
+
+#define PREEMPT_MODEL_ACCESSOR(mode) \
+	bool preempt_model_##mode(void)						 \
+	{									 \
+		WARN_ON_ONCE(preempt_dynamic_mode == preempt_dynamic_undefined); \
+		return preempt_dynamic_mode == preempt_dynamic_##mode;		 \
+	}									 \
+	EXPORT_SYMBOL_GPL(preempt_model_##mode)
+
+PREEMPT_MODEL_ACCESSOR(none);
+PREEMPT_MODEL_ACCESSOR(voluntary);
+PREEMPT_MODEL_ACCESSOR(full);
+
+#else /* !CONFIG_PREEMPT_DYNAMIC */
+
+static inline void preempt_dynamic_init(void) { }
+
+#endif /* #ifdef CONFIG_PREEMPT_DYNAMIC */
+
+/**
+ * yield - yield the current processor to other threads.
+ *
+ * Do not ever use this function, there's a 99% chance you're doing it wrong.
+ *
+ * The scheduler is at all times free to pick the calling task as the most
+ * eligible task to run, if removing the yield() call from your code breaks
+ * it, it's already broken.
+ *
+ * Typical broken usage is:
+ *
+ * while (!event)
+ *	yield();
+ *
+ * where one assumes that yield() will let 'the other' process run that will
+ * make event true. If the current task is a SCHED_FIFO task that will never
+ * happen. Never use yield() as a progress guarantee!!
+ *
+ * If you want to use yield() to wait for something, use wait_event().
+ * If you want to use yield() to be 'nice' for others, use cond_resched().
+ * If you still want to use yield(), do not!
+ */
+void __sched yield(void)
+{
+	set_current_state(TASK_RUNNING);
+	do_sched_yield();
+}
+EXPORT_SYMBOL(yield);
+
+/**
+ * yield_to - yield the current processor to another thread in
+ * your thread group, or accelerate that thread toward the
+ * processor it's on.
+ * @p: target task
+ * @preempt: whether task preemption is allowed or not
+ *
+ * It's the caller's job to ensure that the target task struct
+ * can't go away on us before we can do any checks.
+ *
+ * Return:
+ *	true (>0) if we indeed boosted the target task.
+ *	false (0) if we failed to boost the target.
+ *	-ESRCH if there's no task to yield to.
+ */
+int __sched yield_to(struct task_struct *p, bool preempt)
+{
+	struct task_struct *curr = current;
+	struct rq *rq, *p_rq;
+	unsigned long flags;
+	int yielded = 0;
+
+	local_irq_save(flags);
+	rq = this_rq();
+
+again:
+	p_rq = task_rq(p);
+	/*
+	 * If we're the only runnable task on the rq and target rq also
+	 * has only one task, there's absolutely no point in yielding.
+	 */
+	if (rq->nr_running == 1 && p_rq->nr_running == 1) {
+		yielded = -ESRCH;
+		goto out_irq;
+	}
+
+	double_rq_lock(rq, p_rq);
+	if (task_rq(p) != p_rq) {
+		double_rq_unlock(rq, p_rq);
+		goto again;
+	}
+
+	if (!curr->sched_class->yield_to_task)
+		goto out_unlock;
+
+	if (curr->sched_class != p->sched_class)
+		goto out_unlock;
+
+	if (task_on_cpu(p_rq, p) || !task_is_running(p))
+		goto out_unlock;
+
+	yielded = curr->sched_class->yield_to_task(rq, p);
+	if (yielded) {
+		schedstat_inc(rq->yld_count);
+		/*
+		 * Make p's CPU reschedule; pick_next_entity takes care of
+		 * fairness.
+		 */
+		if (preempt && rq != p_rq)
+			resched_curr(p_rq);
+	}
+
+out_unlock:
+	double_rq_unlock(rq, p_rq);
+out_irq:
+	local_irq_restore(flags);
+
+	if (yielded > 0)
+		schedule();
+
+	return yielded;
+}
+EXPORT_SYMBOL_GPL(yield_to);
+
+int io_schedule_prepare(void)
+{
+	int old_iowait = current->in_iowait;
+
+	current->in_iowait = 1;
+	blk_flush_plug(current->plug, true);
+	return old_iowait;
+}
+
+void io_schedule_finish(int token)
+{
+	current->in_iowait = token;
+}
+
+/*
+ * This task is about to go to sleep on IO. Increment rq->nr_iowait so
+ * that process accounting knows that this is a task in IO wait state.
+ */
+long __sched io_schedule_timeout(long timeout)
+{
+	int token;
+	long ret;
+
+	token = io_schedule_prepare();
+	ret = schedule_timeout(timeout);
+	io_schedule_finish(token);
+
+	return ret;
+}
+EXPORT_SYMBOL(io_schedule_timeout);
+
+void __sched io_schedule(void)
+{
+	int token;
+
+	token = io_schedule_prepare();
+	schedule();
+	io_schedule_finish(token);
+}
+EXPORT_SYMBOL(io_schedule);
+
+/**
+ * sys_sched_get_priority_max - return maximum RT priority.
+ * @policy: scheduling class.
+ *
+ * Return: On success, this syscall returns the maximum
+ * rt_priority that can be used by a given scheduling class.
+ * On failure, a negative error code is returned.
+ */
+SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
+{
+	int ret = -EINVAL;
+
+	switch (policy) {
+	case SCHED_FIFO:
+	case SCHED_RR:
+		ret = MAX_RT_PRIO-1;
+		break;
+	case SCHED_DEADLINE:
+	case SCHED_NORMAL:
+	case SCHED_BATCH:
+	case SCHED_IDLE:
+		ret = 0;
+		break;
+	}
+	return ret;
+}
+
+/**
+ * sys_sched_get_priority_min - return minimum RT priority.
+ * @policy: scheduling class.
+ *
+ * Return: On success, this syscall returns the minimum
+ * rt_priority that can be used by a given scheduling class.
+ * On failure, a negative error code is returned.
+ */
+SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
+{
+	int ret = -EINVAL;
+
+	switch (policy) {
+	case SCHED_FIFO:
+	case SCHED_RR:
+		ret = 1;
+		break;
+	case SCHED_DEADLINE:
+	case SCHED_NORMAL:
+	case SCHED_BATCH:
+	case SCHED_IDLE:
+		ret = 0;
+	}
+	return ret;
+}
+
+static int sched_rr_get_interval(pid_t pid, struct timespec64 *t)
+{
+	struct task_struct *p;
+	unsigned int time_slice;
+	struct rq_flags rf;
+	struct rq *rq;
+	int retval;
+
+	if (pid < 0)
+		return -EINVAL;
+
+	retval = -ESRCH;
+	rcu_read_lock();
+	p = find_process_by_pid(pid);
+	if (!p)
+		goto out_unlock;
+
+	retval = security_task_getscheduler(p);
+	if (retval)
+		goto out_unlock;
+
+	rq = task_rq_lock(p, &rf);
+	time_slice = 0;
+	if (p->sched_class->get_rr_interval)
+		time_slice = p->sched_class->get_rr_interval(rq, p);
+	task_rq_unlock(rq, p, &rf);
+
+	rcu_read_unlock();
+	jiffies_to_timespec64(time_slice, t);
+	return 0;
+
+out_unlock:
+	rcu_read_unlock();
+	return retval;
+}
+
+/**
+ * sys_sched_rr_get_interval - return the default timeslice of a process.
+ * @pid: pid of the process.
+ * @interval: userspace pointer to the timeslice value.
+ *
+ * this syscall writes the default timeslice value of a given process
+ * into the user-space timespec buffer. A value of '0' means infinity.
+ *
+ * Return: On success, 0 and the timeslice is in @interval. Otherwise,
+ * an error code.
+ */
+SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
+		struct __kernel_timespec __user *, interval)
+{
+	struct timespec64 t;
+	int retval = sched_rr_get_interval(pid, &t);
+
+	if (retval == 0)
+		retval = put_timespec64(&t, interval);
+
+	return retval;
+}
+
+#ifdef CONFIG_COMPAT_32BIT_TIME
+SYSCALL_DEFINE2(sched_rr_get_interval_time32, pid_t, pid,
+		struct old_timespec32 __user *, interval)
+{
+	struct timespec64 t;
+	int retval = sched_rr_get_interval(pid, &t);
+
+	if (retval == 0)
+		retval = put_old_timespec32(&t, interval);
+	return retval;
+}
+#endif
+
+void sched_show_task(struct task_struct *p)
+{
+	unsigned long free = 0;
+	int ppid;
+
+	if (!try_get_task_stack(p))
+		return;
+
+	pr_info("task:%-15.15s state:%c", p->comm, task_state_to_char(p));
+
+	if (task_is_running(p))
+		pr_cont("  running task    ");
+#ifdef CONFIG_DEBUG_STACK_USAGE
+	free = stack_not_used(p);
+#endif
+	ppid = 0;
+	rcu_read_lock();
+	if (pid_alive(p))
+		ppid = task_pid_nr(rcu_dereference(p->real_parent));
+	rcu_read_unlock();
+	pr_cont(" stack:%-5lu pid:%-5d ppid:%-6d flags:0x%08lx\n",
+		free, task_pid_nr(p), ppid,
+		read_task_thread_flags(p));
+
+	print_worker_info(KERN_INFO, p);
+	print_stop_info(KERN_INFO, p);
+	show_stack(p, NULL, KERN_INFO);
+	put_task_stack(p);
+}
+EXPORT_SYMBOL_GPL(sched_show_task);
+
+static inline bool
+state_filter_match(unsigned long state_filter, struct task_struct *p)
+{
+	unsigned int state = READ_ONCE(p->__state);
+
+	/* no filter, everything matches */
+	if (!state_filter)
+		return true;
+
+	/* filter, but doesn't match */
+	if (!(state & state_filter))
+		return false;
+
+	/*
+	 * When looking for TASK_UNINTERRUPTIBLE skip TASK_IDLE (allows
+	 * TASK_KILLABLE).
+	 */
+	if (state_filter == TASK_UNINTERRUPTIBLE && (state & TASK_NOLOAD))
+		return false;
+
+	return true;
+}
+
+
+void show_state_filter(unsigned int state_filter)
+{
+	struct task_struct *g, *p;
+
+	rcu_read_lock();
+	for_each_process_thread(g, p) {
+		/*
+		 * reset the NMI-timeout, listing all files on a slow
+		 * console might take a lot of time:
+		 * Also, reset softlockup watchdogs on all CPUs, because
+		 * another CPU might be blocked waiting for us to process
+		 * an IPI.
+		 */
+		touch_nmi_watchdog();
+		touch_all_softlockup_watchdogs();
+		if (state_filter_match(state_filter, p))
+			sched_show_task(p);
+	}
+
+#ifdef CONFIG_SCHED_DEBUG
+	if (!state_filter)
+		sysrq_sched_debug_show();
+#endif
+	rcu_read_unlock();
+	/*
+	 * Only show locks if all tasks are dumped:
+	 */
+	if (!state_filter)
+		debug_show_all_locks();
+}
+
+/**
+ * init_idle - set up an idle thread for a given CPU
+ * @idle: task in question
+ * @cpu: CPU the idle task belongs to
+ *
+ * NOTE: this function does not set the idle thread's NEED_RESCHED
+ * flag, to make booting more robust.
+ */
+void __init init_idle(struct task_struct *idle, int cpu)
+{
+#ifdef CONFIG_SMP
+	struct affinity_context ac = (struct affinity_context) {
+		.new_mask  = cpumask_of(cpu),
+		.flags     = 0,
+	};
+#endif
+	struct rq *rq = cpu_rq(cpu);
+	unsigned long flags;
+
+	__sched_fork(0, idle);
+
+	raw_spin_lock_irqsave(&idle->pi_lock, flags);
+	raw_spin_rq_lock(rq);
+
+	idle->__state = TASK_RUNNING;
+	idle->se.exec_start = sched_clock();
+	/*
+	 * PF_KTHREAD should already be set at this point; regardless, make it
+	 * look like a proper per-CPU kthread.
+	 */
+	idle->flags |= PF_KTHREAD | PF_NO_SETAFFINITY;
+	kthread_set_per_cpu(idle, cpu);
+
+#ifdef CONFIG_SMP
+	/*
+	 * It's possible that init_idle() gets called multiple times on a task,
+	 * in that case do_set_cpus_allowed() will not do the right thing.
+	 *
+	 * And since this is boot we can forgo the serialization.
+	 */
+	set_cpus_allowed_common(idle, &ac);
+#endif
+	/*
+	 * We're having a chicken and egg problem, even though we are
+	 * holding rq->lock, the CPU isn't yet set to this CPU so the
+	 * lockdep check in task_group() will fail.
+	 *
+	 * Similar case to sched_fork(). / Alternatively we could
+	 * use task_rq_lock() here and obtain the other rq->lock.
+	 *
+	 * Silence PROVE_RCU
+	 */
+	rcu_read_lock();
+	__set_task_cpu(idle, cpu);
+	rcu_read_unlock();
+
+	rq->idle = idle;
+	rcu_assign_pointer(rq->curr, idle);
+	idle->on_rq = TASK_ON_RQ_QUEUED;
+#ifdef CONFIG_SMP
+	idle->on_cpu = 1;
+#endif
+	raw_spin_rq_unlock(rq);
+	raw_spin_unlock_irqrestore(&idle->pi_lock, flags);
+
+	/* Set the preempt count _outside_ the spinlocks! */
+	init_idle_preempt_count(idle, cpu);
+
+	/*
+	 * The idle tasks have their own, simple scheduling class:
+	 */
+	idle->sched_class = &idle_sched_class;
+	ftrace_graph_init_idle_task(idle, cpu);
+	vtime_init_idle(idle, cpu);
+#ifdef CONFIG_SMP
+	sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu);
+#endif
+}
+
+#ifdef CONFIG_SMP
+
+int cpuset_cpumask_can_shrink(const struct cpumask *cur,
+			      const struct cpumask *trial)
+{
+	int ret = 1;
+
+	if (cpumask_empty(cur))
+		return ret;
+
+	ret = dl_cpuset_cpumask_can_shrink(cur, trial);
+
+	return ret;
+}
+
+int task_can_attach(struct task_struct *p)
+{
+	int ret = 0;
+
+	/*
+	 * Kthreads which disallow setaffinity shouldn't be moved
+	 * to a new cpuset; we don't want to change their CPU
+	 * affinity and isolating such threads by their set of
+	 * allowed nodes is unnecessary.  Thus, cpusets are not
+	 * applicable for such threads.  This prevents checking for
+	 * success of set_cpus_allowed_ptr() on all attached tasks
+	 * before cpus_mask may be changed.
+	 */
+	if (p->flags & PF_NO_SETAFFINITY)
+		ret = -EINVAL;
+
+	return ret;
+}
+
+bool sched_smp_initialized __read_mostly;
+
+#ifdef CONFIG_NUMA_BALANCING
+/* Migrate current task p to target_cpu */
+int migrate_task_to(struct task_struct *p, int target_cpu)
+{
+	struct migration_arg arg = { p, target_cpu };
+	int curr_cpu = task_cpu(p);
+
+	if (curr_cpu == target_cpu)
+		return 0;
+
+	if (!cpumask_test_cpu(target_cpu, p->cpus_ptr))
+		return -EINVAL;
+
+	/* TODO: This is not properly updating schedstats */
+
+	trace_sched_move_numa(p, curr_cpu, target_cpu);
+	return stop_one_cpu(curr_cpu, migration_cpu_stop, &arg);
+}
+
+/*
+ * Requeue a task on a given node and accurately track the number of NUMA
+ * tasks on the runqueues
+ */
+void sched_setnuma(struct task_struct *p, int nid)
+{
+	bool queued, running;
+	struct rq_flags rf;
+	struct rq *rq;
+
+	rq = task_rq_lock(p, &rf);
+	queued = task_on_rq_queued(p);
+	running = task_current(rq, p);
+
+	if (queued)
+		dequeue_task(rq, p, DEQUEUE_SAVE);
+	if (running)
+		put_prev_task(rq, p);
+
+	p->numa_preferred_nid = nid;
+
+	if (queued)
+		enqueue_task(rq, p, ENQUEUE_RESTORE | ENQUEUE_NOCLOCK);
+	if (running)
+		set_next_task(rq, p);
+	task_rq_unlock(rq, p, &rf);
+}
+#endif /* CONFIG_NUMA_BALANCING */
+
+#ifdef CONFIG_HOTPLUG_CPU
+/*
+ * Ensure that the idle task is using init_mm right before its CPU goes
+ * offline.
+ */
+void idle_task_exit(void)
+{
+	struct mm_struct *mm = current->active_mm;
+
+	BUG_ON(cpu_online(smp_processor_id()));
+	BUG_ON(current != this_rq()->idle);
+
+	if (mm != &init_mm) {
+		switch_mm(mm, &init_mm, current);
+		finish_arch_post_lock_switch();
+	}
+
+	/* finish_cpu(), as ran on the BP, will clean up the active_mm state */
+}
+
+static int __balance_push_cpu_stop(void *arg)
+{
+	struct task_struct *p = arg;
+	struct rq *rq = this_rq();
+	struct rq_flags rf;
+	int cpu;
+
+	raw_spin_lock_irq(&p->pi_lock);
+	rq_lock(rq, &rf);
+
+	update_rq_clock(rq);
+
+	if (task_rq(p) == rq && task_on_rq_queued(p)) {
+		cpu = select_fallback_rq(rq->cpu, p);
+		rq = __migrate_task(rq, &rf, p, cpu);
+	}
+
+	rq_unlock(rq, &rf);
+	raw_spin_unlock_irq(&p->pi_lock);
+
+	put_task_struct(p);
+
+	return 0;
+}
+
+static DEFINE_PER_CPU(struct cpu_stop_work, push_work);
+
+/*
+ * Ensure we only run per-cpu kthreads once the CPU goes !active.
+ *
+ * This is enabled below SCHED_AP_ACTIVE; when !cpu_active(), but only
+ * effective when the hotplug motion is down.
+ */
+static void balance_push(struct rq *rq)
+{
+	struct task_struct *push_task = rq->curr;
+
+	lockdep_assert_rq_held(rq);
+
+	/*
+	 * Ensure the thing is persistent until balance_push_set(.on = false);
+	 */
+	rq->balance_callback = &balance_push_callback;
+
+	/*
+	 * Only active while going offline and when invoked on the outgoing
+	 * CPU.
+	 */
+	if (!cpu_dying(rq->cpu) || rq != this_rq())
+		return;
+
+	/*
+	 * Both the cpu-hotplug and stop task are in this case and are
+	 * required to complete the hotplug process.
+	 */
+	if (kthread_is_per_cpu(push_task) ||
+	    is_migration_disabled(push_task)) {
+
+		/*
+		 * If this is the idle task on the outgoing CPU try to wake
+		 * up the hotplug control thread which might wait for the
+		 * last task to vanish. The rcuwait_active() check is
+		 * accurate here because the waiter is pinned on this CPU
+		 * and can't obviously be running in parallel.
+		 *
+		 * On RT kernels this also has to check whether there are
+		 * pinned and scheduled out tasks on the runqueue. They
+		 * need to leave the migrate disabled section first.
+		 */
+		if (!rq->nr_running && !rq_has_pinned_tasks(rq) &&
+		    rcuwait_active(&rq->hotplug_wait)) {
+			raw_spin_rq_unlock(rq);
+			rcuwait_wake_up(&rq->hotplug_wait);
+			raw_spin_rq_lock(rq);
+		}
+		return;
+	}
+
+	get_task_struct(push_task);
+	/*
+	 * Temporarily drop rq->lock such that we can wake-up the stop task.
+	 * Both preemption and IRQs are still disabled.
+	 */
+	preempt_disable();
+	raw_spin_rq_unlock(rq);
+	stop_one_cpu_nowait(rq->cpu, __balance_push_cpu_stop, push_task,
+			    this_cpu_ptr(&push_work));
+	preempt_enable();
+	/*
+	 * At this point need_resched() is true and we'll take the loop in
+	 * schedule(). The next pick is obviously going to be the stop task
+	 * which kthread_is_per_cpu() and will push this task away.
+	 */
+	raw_spin_rq_lock(rq);
+}
+
+static void balance_push_set(int cpu, bool on)
+{
+	struct rq *rq = cpu_rq(cpu);
+	struct rq_flags rf;
+
+	rq_lock_irqsave(rq, &rf);
+	if (on) {
+		WARN_ON_ONCE(rq->balance_callback);
+		rq->balance_callback = &balance_push_callback;
+	} else if (rq->balance_callback == &balance_push_callback) {
+		rq->balance_callback = NULL;
+	}
+	rq_unlock_irqrestore(rq, &rf);
+}
+
+/*
+ * Invoked from a CPUs hotplug control thread after the CPU has been marked
+ * inactive. All tasks which are not per CPU kernel threads are either
+ * pushed off this CPU now via balance_push() or placed on a different CPU
+ * during wakeup. Wait until the CPU is quiescent.
+ */
+static void balance_hotplug_wait(void)
+{
+	struct rq *rq = this_rq();
+
+	rcuwait_wait_event(&rq->hotplug_wait,
+			   rq->nr_running == 1 && !rq_has_pinned_tasks(rq),
+			   TASK_UNINTERRUPTIBLE);
+}
+
+#else
+
+static inline void balance_push(struct rq *rq)
+{
+}
+
+static inline void balance_push_set(int cpu, bool on)
+{
+}
+
+static inline void balance_hotplug_wait(void)
+{
+}
+
+#endif /* CONFIG_HOTPLUG_CPU */
+
+void set_rq_online(struct rq *rq)
+{
+	if (!rq->online) {
+		const struct sched_class *class;
+
+		cpumask_set_cpu(rq->cpu, rq->rd->online);
+		rq->online = 1;
+
+		for_each_class(class) {
+			if (class->rq_online)
+				class->rq_online(rq);
+		}
+	}
+}
+
+void set_rq_offline(struct rq *rq)
+{
+	if (rq->online) {
+		const struct sched_class *class;
+
+		update_rq_clock(rq);
+		for_each_class(class) {
+			if (class->rq_offline)
+				class->rq_offline(rq);
+		}
+
+		cpumask_clear_cpu(rq->cpu, rq->rd->online);
+		rq->online = 0;
+	}
+}
+
+/*
+ * used to mark begin/end of suspend/resume:
+ */
+static int num_cpus_frozen;
+
+/*
+ * Update cpusets according to cpu_active mask.  If cpusets are
+ * disabled, cpuset_update_active_cpus() becomes a simple wrapper
+ * around partition_sched_domains().
+ *
+ * If we come here as part of a suspend/resume, don't touch cpusets because we
+ * want to restore it back to its original state upon resume anyway.
+ */
+static void cpuset_cpu_active(void)
+{
+	if (cpuhp_tasks_frozen) {
+		/*
+		 * num_cpus_frozen tracks how many CPUs are involved in suspend
+		 * resume sequence. As long as this is not the last online
+		 * operation in the resume sequence, just build a single sched
+		 * domain, ignoring cpusets.
+		 */
+		partition_sched_domains(1, NULL, NULL);
+		if (--num_cpus_frozen)
+			return;
+		/*
+		 * This is the last CPU online operation. So fall through and
+		 * restore the original sched domains by considering the
+		 * cpuset configurations.
+		 */
+		cpuset_force_rebuild();
+	}
+	cpuset_update_active_cpus();
+}
+
+static int cpuset_cpu_inactive(unsigned int cpu)
+{
+	if (!cpuhp_tasks_frozen) {
+		int ret = dl_bw_check_overflow(cpu);
+
+		if (ret)
+			return ret;
+		cpuset_update_active_cpus();
+	} else {
+		num_cpus_frozen++;
+		partition_sched_domains(1, NULL, NULL);
+	}
+	return 0;
+}
+
+int sched_cpu_activate(unsigned int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	struct rq_flags rf;
+
+	/*
+	 * Clear the balance_push callback and prepare to schedule
+	 * regular tasks.
+	 */
+	balance_push_set(cpu, false);
+
+#ifdef CONFIG_SCHED_SMT
+	/*
+	 * When going up, increment the number of cores with SMT present.
+	 */
+	if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
+		static_branch_inc_cpuslocked(&sched_smt_present);
+#endif
+	set_cpu_active(cpu, true);
+
+	if (sched_smp_initialized) {
+		sched_update_numa(cpu, true);
+		sched_domains_numa_masks_set(cpu);
+		cpuset_cpu_active();
+	}
+
+	/*
+	 * Put the rq online, if not already. This happens:
+	 *
+	 * 1) In the early boot process, because we build the real domains
+	 *    after all CPUs have been brought up.
+	 *
+	 * 2) At runtime, if cpuset_cpu_active() fails to rebuild the
+	 *    domains.
+	 */
+	rq_lock_irqsave(rq, &rf);
+	if (rq->rd) {
+		BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
+		set_rq_online(rq);
+	}
+	rq_unlock_irqrestore(rq, &rf);
+
+	return 0;
+}
+
+int sched_cpu_deactivate(unsigned int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	struct rq_flags rf;
+	int ret;
+
+	/*
+	 * Remove CPU from nohz.idle_cpus_mask to prevent participating in
+	 * load balancing when not active
+	 */
+	nohz_balance_exit_idle(rq);
+
+	set_cpu_active(cpu, false);
+
+	/*
+	 * From this point forward, this CPU will refuse to run any task that
+	 * is not: migrate_disable() or KTHREAD_IS_PER_CPU, and will actively
+	 * push those tasks away until this gets cleared, see
+	 * sched_cpu_dying().
+	 */
+	balance_push_set(cpu, true);
+
+	/*
+	 * We've cleared cpu_active_mask / set balance_push, wait for all
+	 * preempt-disabled and RCU users of this state to go away such that
+	 * all new such users will observe it.
+	 *
+	 * Specifically, we rely on ttwu to no longer target this CPU, see
+	 * ttwu_queue_cond() and is_cpu_allowed().
+	 *
+	 * Do sync before park smpboot threads to take care the rcu boost case.
+	 */
+	synchronize_rcu();
+
+	rq_lock_irqsave(rq, &rf);
+	if (rq->rd) {
+		BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
+		set_rq_offline(rq);
+	}
+	rq_unlock_irqrestore(rq, &rf);
+
+#ifdef CONFIG_SCHED_SMT
+	/*
+	 * When going down, decrement the number of cores with SMT present.
+	 */
+	if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
+		static_branch_dec_cpuslocked(&sched_smt_present);
+
+	sched_core_cpu_deactivate(cpu);
+#endif
+
+	if (!sched_smp_initialized)
+		return 0;
+
+	sched_update_numa(cpu, false);
+	ret = cpuset_cpu_inactive(cpu);
+	if (ret) {
+		balance_push_set(cpu, false);
+		set_cpu_active(cpu, true);
+		sched_update_numa(cpu, true);
+		return ret;
+	}
+	sched_domains_numa_masks_clear(cpu);
+	return 0;
+}
+
+static void sched_rq_cpu_starting(unsigned int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	rq->calc_load_update = calc_load_update;
+	update_max_interval();
+}
+
+int sched_cpu_starting(unsigned int cpu)
+{
+	sched_core_cpu_starting(cpu);
+	sched_rq_cpu_starting(cpu);
+	sched_tick_start(cpu);
+	return 0;
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+
+/*
+ * Invoked immediately before the stopper thread is invoked to bring the
+ * CPU down completely. At this point all per CPU kthreads except the
+ * hotplug thread (current) and the stopper thread (inactive) have been
+ * either parked or have been unbound from the outgoing CPU. Ensure that
+ * any of those which might be on the way out are gone.
+ *
+ * If after this point a bound task is being woken on this CPU then the
+ * responsible hotplug callback has failed to do it's job.
+ * sched_cpu_dying() will catch it with the appropriate fireworks.
+ */
+int sched_cpu_wait_empty(unsigned int cpu)
+{
+	balance_hotplug_wait();
+	return 0;
+}
+
+/*
+ * Since this CPU is going 'away' for a while, fold any nr_active delta we
+ * might have. Called from the CPU stopper task after ensuring that the
+ * stopper is the last running task on the CPU, so nr_active count is
+ * stable. We need to take the teardown thread which is calling this into
+ * account, so we hand in adjust = 1 to the load calculation.
+ *
+ * Also see the comment "Global load-average calculations".
+ */
+static void calc_load_migrate(struct rq *rq)
+{
+	long delta = calc_load_fold_active(rq, 1);
+
+	if (delta)
+		atomic_long_add(delta, &calc_load_tasks);
+}
+
+static void dump_rq_tasks(struct rq *rq, const char *loglvl)
+{
+	struct task_struct *g, *p;
+	int cpu = cpu_of(rq);
+
+	lockdep_assert_rq_held(rq);
+
+	printk("%sCPU%d enqueued tasks (%u total):\n", loglvl, cpu, rq->nr_running);
+	for_each_process_thread(g, p) {
+		if (task_cpu(p) != cpu)
+			continue;
+
+		if (!task_on_rq_queued(p))
+			continue;
+
+		printk("%s\tpid: %d, name: %s\n", loglvl, p->pid, p->comm);
+	}
+}
+
+int sched_cpu_dying(unsigned int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	struct rq_flags rf;
+
+	/* Handle pending wakeups and then migrate everything off */
+	sched_tick_stop(cpu);
+
+	rq_lock_irqsave(rq, &rf);
+	if (rq->nr_running != 1 || rq_has_pinned_tasks(rq)) {
+		WARN(true, "Dying CPU not properly vacated!");
+		dump_rq_tasks(rq, KERN_WARNING);
+	}
+	rq_unlock_irqrestore(rq, &rf);
+
+	calc_load_migrate(rq);
+	update_max_interval();
+	hrtick_clear(rq);
+	sched_core_cpu_dying(cpu);
+	return 0;
+}
+#endif
+
+void __init sched_init_smp(void)
+{
+	sched_init_numa(NUMA_NO_NODE);
+
+	/*
+	 * There's no userspace yet to cause hotplug operations; hence all the
+	 * CPU masks are stable and all blatant races in the below code cannot
+	 * happen.
+	 */
+	mutex_lock(&sched_domains_mutex);
+	sched_init_domains(cpu_active_mask);
+	mutex_unlock(&sched_domains_mutex);
+
+	/* Move init over to a non-isolated CPU */
+	if (set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_TYPE_DOMAIN)) < 0)
+		BUG();
+	current->flags &= ~PF_NO_SETAFFINITY;
+	sched_init_granularity();
+
+	init_sched_rt_class();
+	init_sched_dl_class();
+
+	sched_smp_initialized = true;
+}
+
+static int __init migration_init(void)
+{
+	sched_cpu_starting(smp_processor_id());
+	return 0;
+}
+early_initcall(migration_init);
+
+#else
+void __init sched_init_smp(void)
+{
+	sched_init_granularity();
+}
+#endif /* CONFIG_SMP */
+
+int in_sched_functions(unsigned long addr)
+{
+	return in_lock_functions(addr) ||
+		(addr >= (unsigned long)__sched_text_start
+		&& addr < (unsigned long)__sched_text_end);
+}
+
+#ifdef CONFIG_CGROUP_SCHED
+/*
+ * Default task group.
+ * Every task in system belongs to this group at bootup.
+ */
+struct task_group root_task_group;
+LIST_HEAD(task_groups);
+
+/* Cacheline aligned slab cache for task_group */
+static struct kmem_cache *task_group_cache __read_mostly;
+#endif
+
+void __init sched_init(void)
+{
+	unsigned long ptr = 0;
+	int i;
+
+	/* Make sure the linker didn't screw up */
+	BUG_ON(&idle_sched_class != &fair_sched_class + 1 ||
+	       &fair_sched_class != &rt_sched_class + 1 ||
+	       &rt_sched_class   != &dl_sched_class + 1);
+#ifdef CONFIG_SMP
+	BUG_ON(&dl_sched_class != &stop_sched_class + 1);
+#endif
+
+	wait_bit_init();
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	ptr += 2 * nr_cpu_ids * sizeof(void **);
+#endif
+#ifdef CONFIG_RT_GROUP_SCHED
+	ptr += 2 * nr_cpu_ids * sizeof(void **);
+#endif
+	if (ptr) {
+		ptr = (unsigned long)kzalloc(ptr, GFP_NOWAIT);
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+		root_task_group.se = (struct sched_entity **)ptr;
+		ptr += nr_cpu_ids * sizeof(void **);
+
+		root_task_group.cfs_rq = (struct cfs_rq **)ptr;
+		ptr += nr_cpu_ids * sizeof(void **);
+
+		root_task_group.shares = ROOT_TASK_GROUP_LOAD;
+		init_cfs_bandwidth(&root_task_group.cfs_bandwidth, NULL);
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+#ifdef CONFIG_RT_GROUP_SCHED
+		root_task_group.rt_se = (struct sched_rt_entity **)ptr;
+		ptr += nr_cpu_ids * sizeof(void **);
+
+		root_task_group.rt_rq = (struct rt_rq **)ptr;
+		ptr += nr_cpu_ids * sizeof(void **);
+
+#endif /* CONFIG_RT_GROUP_SCHED */
+	}
+
+	init_rt_bandwidth(&def_rt_bandwidth, global_rt_period(), global_rt_runtime());
+
+#ifdef CONFIG_SMP
+	init_defrootdomain();
+#endif
+
+#ifdef CONFIG_RT_GROUP_SCHED
+	init_rt_bandwidth(&root_task_group.rt_bandwidth,
+			global_rt_period(), global_rt_runtime());
+#endif /* CONFIG_RT_GROUP_SCHED */
+
+#ifdef CONFIG_CGROUP_SCHED
+	task_group_cache = KMEM_CACHE(task_group, 0);
+
+	list_add(&root_task_group.list, &task_groups);
+	INIT_LIST_HEAD(&root_task_group.children);
+	INIT_LIST_HEAD(&root_task_group.siblings);
+	autogroup_init(&init_task);
+#endif /* CONFIG_CGROUP_SCHED */
+
+	for_each_possible_cpu(i) {
+		struct rq *rq;
+
+		rq = cpu_rq(i);
+		raw_spin_lock_init(&rq->__lock);
+		rq->nr_running = 0;
+		rq->calc_load_active = 0;
+		rq->calc_load_update = jiffies + LOAD_FREQ;
+		init_cfs_rq(&rq->cfs);
+		init_rt_rq(&rq->rt);
+		init_dl_rq(&rq->dl);
+#ifdef CONFIG_FAIR_GROUP_SCHED
+		INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
+		rq->tmp_alone_branch = &rq->leaf_cfs_rq_list;
+		/*
+		 * How much CPU bandwidth does root_task_group get?
+		 *
+		 * In case of task-groups formed thr' the cgroup filesystem, it
+		 * gets 100% of the CPU resources in the system. This overall
+		 * system CPU resource is divided among the tasks of
+		 * root_task_group and its child task-groups in a fair manner,
+		 * based on each entity's (task or task-group's) weight
+		 * (se->load.weight).
+		 *
+		 * In other words, if root_task_group has 10 tasks of weight
+		 * 1024) and two child groups A0 and A1 (of weight 1024 each),
+		 * then A0's share of the CPU resource is:
+		 *
+		 *	A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
+		 *
+		 * We achieve this by letting root_task_group's tasks sit
+		 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
+		 */
+		init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL);
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+		rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
+#ifdef CONFIG_RT_GROUP_SCHED
+		init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL);
+#endif
+#ifdef CONFIG_SMP
+		rq->sd = NULL;
+		rq->rd = NULL;
+		rq->cpu_capacity = rq->cpu_capacity_orig = SCHED_CAPACITY_SCALE;
+		rq->balance_callback = &balance_push_callback;
+		rq->active_balance = 0;
+		rq->next_balance = jiffies;
+		rq->push_cpu = 0;
+		rq->cpu = i;
+		rq->online = 0;
+		rq->idle_stamp = 0;
+		rq->avg_idle = 2*sysctl_sched_migration_cost;
+		rq->wake_stamp = jiffies;
+		rq->wake_avg_idle = rq->avg_idle;
+		rq->max_idle_balance_cost = sysctl_sched_migration_cost;
+
+		INIT_LIST_HEAD(&rq->cfs_tasks);
+
+		rq_attach_root(rq, &def_root_domain);
+#ifdef CONFIG_NO_HZ_COMMON
+		rq->last_blocked_load_update_tick = jiffies;
+		atomic_set(&rq->nohz_flags, 0);
+
+		INIT_CSD(&rq->nohz_csd, nohz_csd_func, rq);
+#endif
+#ifdef CONFIG_HOTPLUG_CPU
+		rcuwait_init(&rq->hotplug_wait);
+#endif
+#endif /* CONFIG_SMP */
+		hrtick_rq_init(rq);
+		atomic_set(&rq->nr_iowait, 0);
+
+#ifdef CONFIG_SCHED_CORE
+		rq->core = rq;
+		rq->core_pick = NULL;
+		rq->core_enabled = 0;
+		rq->core_tree = RB_ROOT;
+		rq->core_forceidle_count = 0;
+		rq->core_forceidle_occupation = 0;
+		rq->core_forceidle_start = 0;
+
+		rq->core_cookie = 0UL;
+#endif
+		zalloc_cpumask_var_node(&rq->scratch_mask, GFP_KERNEL, cpu_to_node(i));
+	}
+
+	set_load_weight(&init_task, false);
+
+	/*
+	 * The boot idle thread does lazy MMU switching as well:
+	 */
+	mmgrab_lazy_tlb(&init_mm);
+	enter_lazy_tlb(&init_mm, current);
+
+	/*
+	 * The idle task doesn't need the kthread struct to function, but it
+	 * is dressed up as a per-CPU kthread and thus needs to play the part
+	 * if we want to avoid special-casing it in code that deals with per-CPU
+	 * kthreads.
+	 */
+	WARN_ON(!set_kthread_struct(current));
+
+	/*
+	 * Make us the idle thread. Technically, schedule() should not be
+	 * called from this thread, however somewhere below it might be,
+	 * but because we are the idle thread, we just pick up running again
+	 * when this runqueue becomes "idle".
+	 */
+	init_idle(current, smp_processor_id());
+
+	calc_load_update = jiffies + LOAD_FREQ;
+
+#ifdef CONFIG_SMP
+	idle_thread_set_boot_cpu();
+	balance_push_set(smp_processor_id(), false);
+#endif
+	init_sched_fair_class();
+
+	psi_init();
+
+	init_uclamp();
+
+	preempt_dynamic_init();
+
+	scheduler_running = 1;
+}
+
+#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
+
+void __might_sleep(const char *file, int line)
+{
+	unsigned int state = get_current_state();
+	/*
+	 * Blocking primitives will set (and therefore destroy) current->state,
+	 * since we will exit with TASK_RUNNING make sure we enter with it,
+	 * otherwise we will destroy state.
+	 */
+	WARN_ONCE(state != TASK_RUNNING && current->task_state_change,
+			"do not call blocking ops when !TASK_RUNNING; "
+			"state=%x set at [<%p>] %pS\n", state,
+			(void *)current->task_state_change,
+			(void *)current->task_state_change);
+
+	__might_resched(file, line, 0);
+}
+EXPORT_SYMBOL(__might_sleep);
+
+static void print_preempt_disable_ip(int preempt_offset, unsigned long ip)
+{
+	if (!IS_ENABLED(CONFIG_DEBUG_PREEMPT))
+		return;
+
+	if (preempt_count() == preempt_offset)
+		return;
+
+	pr_err("Preemption disabled at:");
+	print_ip_sym(KERN_ERR, ip);
+}
+
+static inline bool resched_offsets_ok(unsigned int offsets)
+{
+	unsigned int nested = preempt_count();
+
+	nested += rcu_preempt_depth() << MIGHT_RESCHED_RCU_SHIFT;
+
+	return nested == offsets;
+}
+
+void __might_resched(const char *file, int line, unsigned int offsets)
+{
+	/* Ratelimiting timestamp: */
+	static unsigned long prev_jiffy;
+
+	unsigned long preempt_disable_ip;
+
+	/* WARN_ON_ONCE() by default, no rate limit required: */
+	rcu_sleep_check();
+
+	if ((resched_offsets_ok(offsets) && !irqs_disabled() &&
+	     !is_idle_task(current) && !current->non_block_count) ||
+	    system_state == SYSTEM_BOOTING || system_state > SYSTEM_RUNNING ||
+	    oops_in_progress)
+		return;
+
+	if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
+		return;
+	prev_jiffy = jiffies;
+
+	/* Save this before calling printk(), since that will clobber it: */
+	preempt_disable_ip = get_preempt_disable_ip(current);
+
+	pr_err("BUG: sleeping function called from invalid context at %s:%d\n",
+	       file, line);
+	pr_err("in_atomic(): %d, irqs_disabled(): %d, non_block: %d, pid: %d, name: %s\n",
+	       in_atomic(), irqs_disabled(), current->non_block_count,
+	       current->pid, current->comm);
+	pr_err("preempt_count: %x, expected: %x\n", preempt_count(),
+	       offsets & MIGHT_RESCHED_PREEMPT_MASK);
+
+	if (IS_ENABLED(CONFIG_PREEMPT_RCU)) {
+		pr_err("RCU nest depth: %d, expected: %u\n",
+		       rcu_preempt_depth(), offsets >> MIGHT_RESCHED_RCU_SHIFT);
+	}
+
+	if (task_stack_end_corrupted(current))
+		pr_emerg("Thread overran stack, or stack corrupted\n");
+
+	debug_show_held_locks(current);
+	if (irqs_disabled())
+		print_irqtrace_events(current);
+
+	print_preempt_disable_ip(offsets & MIGHT_RESCHED_PREEMPT_MASK,
+				 preempt_disable_ip);
+
+	dump_stack();
+	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
+}
+EXPORT_SYMBOL(__might_resched);
+
+void __cant_sleep(const char *file, int line, int preempt_offset)
+{
+	static unsigned long prev_jiffy;
+
+	if (irqs_disabled())
+		return;
+
+	if (!IS_ENABLED(CONFIG_PREEMPT_COUNT))
+		return;
+
+	if (preempt_count() > preempt_offset)
+		return;
+
+	if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
+		return;
+	prev_jiffy = jiffies;
+
+	printk(KERN_ERR "BUG: assuming atomic context at %s:%d\n", file, line);
+	printk(KERN_ERR "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
+			in_atomic(), irqs_disabled(),
+			current->pid, current->comm);
+
+	debug_show_held_locks(current);
+	dump_stack();
+	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
+}
+EXPORT_SYMBOL_GPL(__cant_sleep);
+
+#ifdef CONFIG_SMP
+void __cant_migrate(const char *file, int line)
+{
+	static unsigned long prev_jiffy;
+
+	if (irqs_disabled())
+		return;
+
+	if (is_migration_disabled(current))
+		return;
+
+	if (!IS_ENABLED(CONFIG_PREEMPT_COUNT))
+		return;
+
+	if (preempt_count() > 0)
+		return;
+
+	if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
+		return;
+	prev_jiffy = jiffies;
+
+	pr_err("BUG: assuming non migratable context at %s:%d\n", file, line);
+	pr_err("in_atomic(): %d, irqs_disabled(): %d, migration_disabled() %u pid: %d, name: %s\n",
+	       in_atomic(), irqs_disabled(), is_migration_disabled(current),
+	       current->pid, current->comm);
+
+	debug_show_held_locks(current);
+	dump_stack();
+	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
+}
+EXPORT_SYMBOL_GPL(__cant_migrate);
+#endif
+#endif
+
+#ifdef CONFIG_MAGIC_SYSRQ
+void normalize_rt_tasks(void)
+{
+	struct task_struct *g, *p;
+	struct sched_attr attr = {
+		.sched_policy = SCHED_NORMAL,
+	};
+
+	read_lock(&tasklist_lock);
+	for_each_process_thread(g, p) {
+		/*
+		 * Only normalize user tasks:
+		 */
+		if (p->flags & PF_KTHREAD)
+			continue;
+
+		p->se.exec_start = 0;
+		schedstat_set(p->stats.wait_start,  0);
+		schedstat_set(p->stats.sleep_start, 0);
+		schedstat_set(p->stats.block_start, 0);
+
+		if (!dl_task(p) && !rt_task(p)) {
+			/*
+			 * Renice negative nice level userspace
+			 * tasks back to 0:
+			 */
+			if (task_nice(p) < 0)
+				set_user_nice(p, 0);
+			continue;
+		}
+
+		__sched_setscheduler(p, &attr, false, false);
+	}
+	read_unlock(&tasklist_lock);
+}
+
+#endif /* CONFIG_MAGIC_SYSRQ */
+
+#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
+/*
+ * These functions are only useful for the IA64 MCA handling, or kdb.
+ *
+ * They can only be called when the whole system has been
+ * stopped - every CPU needs to be quiescent, and no scheduling
+ * activity can take place. Using them for anything else would
+ * be a serious bug, and as a result, they aren't even visible
+ * under any other configuration.
+ */
+
+/**
+ * curr_task - return the current task for a given CPU.
+ * @cpu: the processor in question.
+ *
+ * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
+ *
+ * Return: The current task for @cpu.
+ */
+struct task_struct *curr_task(int cpu)
+{
+	return cpu_curr(cpu);
+}
+
+#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
+
+#ifdef CONFIG_IA64
+/**
+ * ia64_set_curr_task - set the current task for a given CPU.
+ * @cpu: the processor in question.
+ * @p: the task pointer to set.
+ *
+ * Description: This function must only be used when non-maskable interrupts
+ * are serviced on a separate stack. It allows the architecture to switch the
+ * notion of the current task on a CPU in a non-blocking manner. This function
+ * must be called with all CPU's synchronized, and interrupts disabled, the
+ * and caller must save the original value of the current task (see
+ * curr_task() above) and restore that value before reenabling interrupts and
+ * re-starting the system.
+ *
+ * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
+ */
+void ia64_set_curr_task(int cpu, struct task_struct *p)
+{
+	cpu_curr(cpu) = p;
+}
+
+#endif
+
+#ifdef CONFIG_CGROUP_SCHED
+/* task_group_lock serializes the addition/removal of task groups */
+static DEFINE_SPINLOCK(task_group_lock);
+
+static inline void alloc_uclamp_sched_group(struct task_group *tg,
+					    struct task_group *parent)
+{
+#ifdef CONFIG_UCLAMP_TASK_GROUP
+	enum uclamp_id clamp_id;
+
+	for_each_clamp_id(clamp_id) {
+		uclamp_se_set(&tg->uclamp_req[clamp_id],
+			      uclamp_none(clamp_id), false);
+		tg->uclamp[clamp_id] = parent->uclamp[clamp_id];
+	}
+#endif
+}
+
+static void sched_free_group(struct task_group *tg)
+{
+	free_fair_sched_group(tg);
+	free_rt_sched_group(tg);
+	autogroup_free(tg);
+	kmem_cache_free(task_group_cache, tg);
+}
+
+static void sched_free_group_rcu(struct rcu_head *rcu)
+{
+	sched_free_group(container_of(rcu, struct task_group, rcu));
+}
+
+static void sched_unregister_group(struct task_group *tg)
+{
+	unregister_fair_sched_group(tg);
+	unregister_rt_sched_group(tg);
+	/*
+	 * We have to wait for yet another RCU grace period to expire, as
+	 * print_cfs_stats() might run concurrently.
+	 */
+	call_rcu(&tg->rcu, sched_free_group_rcu);
+}
+
+/* allocate runqueue etc for a new task group */
+struct task_group *sched_create_group(struct task_group *parent)
+{
+	struct task_group *tg;
+
+	tg = kmem_cache_alloc(task_group_cache, GFP_KERNEL | __GFP_ZERO);
+	if (!tg)
+		return ERR_PTR(-ENOMEM);
+
+	if (!alloc_fair_sched_group(tg, parent))
+		goto err;
+
+	if (!alloc_rt_sched_group(tg, parent))
+		goto err;
+
+	alloc_uclamp_sched_group(tg, parent);
+
+	return tg;
+
+err:
+	sched_free_group(tg);
+	return ERR_PTR(-ENOMEM);
+}
+
+void sched_online_group(struct task_group *tg, struct task_group *parent)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&task_group_lock, flags);
+	list_add_rcu(&tg->list, &task_groups);
+
+	/* Root should already exist: */
+	WARN_ON(!parent);
+
+	tg->parent = parent;
+	INIT_LIST_HEAD(&tg->children);
+	list_add_rcu(&tg->siblings, &parent->children);
+	spin_unlock_irqrestore(&task_group_lock, flags);
+
+	online_fair_sched_group(tg);
+}
+
+/* rcu callback to free various structures associated with a task group */
+static void sched_unregister_group_rcu(struct rcu_head *rhp)
+{
+	/* Now it should be safe to free those cfs_rqs: */
+	sched_unregister_group(container_of(rhp, struct task_group, rcu));
+}
+
+void sched_destroy_group(struct task_group *tg)
+{
+	/* Wait for possible concurrent references to cfs_rqs complete: */
+	call_rcu(&tg->rcu, sched_unregister_group_rcu);
+}
+
+void sched_release_group(struct task_group *tg)
+{
+	unsigned long flags;
+
+	/*
+	 * Unlink first, to avoid walk_tg_tree_from() from finding us (via
+	 * sched_cfs_period_timer()).
+	 *
+	 * For this to be effective, we have to wait for all pending users of
+	 * this task group to leave their RCU critical section to ensure no new
+	 * user will see our dying task group any more. Specifically ensure
+	 * that tg_unthrottle_up() won't add decayed cfs_rq's to it.
+	 *
+	 * We therefore defer calling unregister_fair_sched_group() to
+	 * sched_unregister_group() which is guarantied to get called only after the
+	 * current RCU grace period has expired.
+	 */
+	spin_lock_irqsave(&task_group_lock, flags);
+	list_del_rcu(&tg->list);
+	list_del_rcu(&tg->siblings);
+	spin_unlock_irqrestore(&task_group_lock, flags);
+}
+
+static struct task_group *sched_get_task_group(struct task_struct *tsk)
+{
+	struct task_group *tg;
+
+	/*
+	 * All callers are synchronized by task_rq_lock(); we do not use RCU
+	 * which is pointless here. Thus, we pass "true" to task_css_check()
+	 * to prevent lockdep warnings.
+	 */
+	tg = container_of(task_css_check(tsk, cpu_cgrp_id, true),
+			  struct task_group, css);
+	tg = autogroup_task_group(tsk, tg);
+
+	return tg;
+}
+
+static void sched_change_group(struct task_struct *tsk, struct task_group *group)
+{
+	tsk->sched_task_group = group;
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	if (tsk->sched_class->task_change_group)
+		tsk->sched_class->task_change_group(tsk);
+	else
+#endif
+		set_task_rq(tsk, task_cpu(tsk));
+}
+
+/*
+ * Change task's runqueue when it moves between groups.
+ *
+ * The caller of this function should have put the task in its new group by
+ * now. This function just updates tsk->se.cfs_rq and tsk->se.parent to reflect
+ * its new group.
+ */
+void sched_move_task(struct task_struct *tsk)
+{
+	int queued, running, queue_flags =
+		DEQUEUE_SAVE | DEQUEUE_MOVE | DEQUEUE_NOCLOCK;
+	struct task_group *group;
+	struct rq_flags rf;
+	struct rq *rq;
+
+	rq = task_rq_lock(tsk, &rf);
+	/*
+	 * Esp. with SCHED_AUTOGROUP enabled it is possible to get superfluous
+	 * group changes.
+	 */
+	group = sched_get_task_group(tsk);
+	if (group == tsk->sched_task_group)
+		goto unlock;
+
+	update_rq_clock(rq);
+
+	running = task_current(rq, tsk);
+	queued = task_on_rq_queued(tsk);
+
+	if (queued)
+		dequeue_task(rq, tsk, queue_flags);
+	if (running)
+		put_prev_task(rq, tsk);
+
+	sched_change_group(tsk, group);
+
+	if (queued)
+		enqueue_task(rq, tsk, queue_flags);
+	if (running) {
+		set_next_task(rq, tsk);
+		/*
+		 * After changing group, the running task may have joined a
+		 * throttled one but it's still the running task. Trigger a
+		 * resched to make sure that task can still run.
+		 */
+		resched_curr(rq);
+	}
+
+unlock:
+	task_rq_unlock(rq, tsk, &rf);
+}
+
+static inline struct task_group *css_tg(struct cgroup_subsys_state *css)
+{
+	return css ? container_of(css, struct task_group, css) : NULL;
+}
+
+static struct cgroup_subsys_state *
+cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
+{
+	struct task_group *parent = css_tg(parent_css);
+	struct task_group *tg;
+
+	if (!parent) {
+		/* This is early initialization for the top cgroup */
+		return &root_task_group.css;
+	}
+
+	tg = sched_create_group(parent);
+	if (IS_ERR(tg))
+		return ERR_PTR(-ENOMEM);
+
+	return &tg->css;
+}
+
+/* Expose task group only after completing cgroup initialization */
+static int cpu_cgroup_css_online(struct cgroup_subsys_state *css)
+{
+	struct task_group *tg = css_tg(css);
+	struct task_group *parent = css_tg(css->parent);
+
+	if (parent)
+		sched_online_group(tg, parent);
+
+#ifdef CONFIG_UCLAMP_TASK_GROUP
+	/* Propagate the effective uclamp value for the new group */
+	mutex_lock(&uclamp_mutex);
+	rcu_read_lock();
+	cpu_util_update_eff(css);
+	rcu_read_unlock();
+	mutex_unlock(&uclamp_mutex);
+#endif
+
+	return 0;
+}
+
+static void cpu_cgroup_css_released(struct cgroup_subsys_state *css)
+{
+	struct task_group *tg = css_tg(css);
+
+	sched_release_group(tg);
+}
+
+static void cpu_cgroup_css_free(struct cgroup_subsys_state *css)
+{
+	struct task_group *tg = css_tg(css);
+
+	/*
+	 * Relies on the RCU grace period between css_released() and this.
+	 */
+	sched_unregister_group(tg);
+}
+
+#ifdef CONFIG_RT_GROUP_SCHED
+static int cpu_cgroup_can_attach(struct cgroup_taskset *tset)
+{
+	struct task_struct *task;
+	struct cgroup_subsys_state *css;
+
+	cgroup_taskset_for_each(task, css, tset) {
+		if (!sched_rt_can_attach(css_tg(css), task))
+			return -EINVAL;
+	}
+	return 0;
+}
+#endif
+
+static void cpu_cgroup_attach(struct cgroup_taskset *tset)
+{
+	struct task_struct *task;
+	struct cgroup_subsys_state *css;
+
+	cgroup_taskset_for_each(task, css, tset)
+		sched_move_task(task);
+}
+
+#ifdef CONFIG_UCLAMP_TASK_GROUP
+static void cpu_util_update_eff(struct cgroup_subsys_state *css)
+{
+	struct cgroup_subsys_state *top_css = css;
+	struct uclamp_se *uc_parent = NULL;
+	struct uclamp_se *uc_se = NULL;
+	unsigned int eff[UCLAMP_CNT];
+	enum uclamp_id clamp_id;
+	unsigned int clamps;
+
+	lockdep_assert_held(&uclamp_mutex);
+	SCHED_WARN_ON(!rcu_read_lock_held());
+
+	css_for_each_descendant_pre(css, top_css) {
+		uc_parent = css_tg(css)->parent
+			? css_tg(css)->parent->uclamp : NULL;
+
+		for_each_clamp_id(clamp_id) {
+			/* Assume effective clamps matches requested clamps */
+			eff[clamp_id] = css_tg(css)->uclamp_req[clamp_id].value;
+			/* Cap effective clamps with parent's effective clamps */
+			if (uc_parent &&
+			    eff[clamp_id] > uc_parent[clamp_id].value) {
+				eff[clamp_id] = uc_parent[clamp_id].value;
+			}
+		}
+		/* Ensure protection is always capped by limit */
+		eff[UCLAMP_MIN] = min(eff[UCLAMP_MIN], eff[UCLAMP_MAX]);
+
+		/* Propagate most restrictive effective clamps */
+		clamps = 0x0;
+		uc_se = css_tg(css)->uclamp;
+		for_each_clamp_id(clamp_id) {
+			if (eff[clamp_id] == uc_se[clamp_id].value)
+				continue;
+			uc_se[clamp_id].value = eff[clamp_id];
+			uc_se[clamp_id].bucket_id = uclamp_bucket_id(eff[clamp_id]);
+			clamps |= (0x1 << clamp_id);
+		}
+		if (!clamps) {
+			css = css_rightmost_descendant(css);
+			continue;
+		}
+
+		/* Immediately update descendants RUNNABLE tasks */
+		uclamp_update_active_tasks(css);
+	}
+}
+
+/*
+ * Integer 10^N with a given N exponent by casting to integer the literal "1eN"
+ * C expression. Since there is no way to convert a macro argument (N) into a
+ * character constant, use two levels of macros.
+ */
+#define _POW10(exp) ((unsigned int)1e##exp)
+#define POW10(exp) _POW10(exp)
+
+struct uclamp_request {
+#define UCLAMP_PERCENT_SHIFT	2
+#define UCLAMP_PERCENT_SCALE	(100 * POW10(UCLAMP_PERCENT_SHIFT))
+	s64 percent;
+	u64 util;
+	int ret;
+};
+
+static inline struct uclamp_request
+capacity_from_percent(char *buf)
+{
+	struct uclamp_request req = {
+		.percent = UCLAMP_PERCENT_SCALE,
+		.util = SCHED_CAPACITY_SCALE,
+		.ret = 0,
+	};
+
+	buf = strim(buf);
+	if (strcmp(buf, "max")) {
+		req.ret = cgroup_parse_float(buf, UCLAMP_PERCENT_SHIFT,
+					     &req.percent);
+		if (req.ret)
+			return req;
+		if ((u64)req.percent > UCLAMP_PERCENT_SCALE) {
+			req.ret = -ERANGE;
+			return req;
+		}
+
+		req.util = req.percent << SCHED_CAPACITY_SHIFT;
+		req.util = DIV_ROUND_CLOSEST_ULL(req.util, UCLAMP_PERCENT_SCALE);
+	}
+
+	return req;
+}
+
+static ssize_t cpu_uclamp_write(struct kernfs_open_file *of, char *buf,
+				size_t nbytes, loff_t off,
+				enum uclamp_id clamp_id)
+{
+	struct uclamp_request req;
+	struct task_group *tg;
+
+	req = capacity_from_percent(buf);
+	if (req.ret)
+		return req.ret;
+
+	static_branch_enable(&sched_uclamp_used);
+
+	mutex_lock(&uclamp_mutex);
+	rcu_read_lock();
+
+	tg = css_tg(of_css(of));
+	if (tg->uclamp_req[clamp_id].value != req.util)
+		uclamp_se_set(&tg->uclamp_req[clamp_id], req.util, false);
+
+	/*
+	 * Because of not recoverable conversion rounding we keep track of the
+	 * exact requested value
+	 */
+	tg->uclamp_pct[clamp_id] = req.percent;
+
+	/* Update effective clamps to track the most restrictive value */
+	cpu_util_update_eff(of_css(of));
+
+	rcu_read_unlock();
+	mutex_unlock(&uclamp_mutex);
+
+	return nbytes;
+}
+
+static ssize_t cpu_uclamp_min_write(struct kernfs_open_file *of,
+				    char *buf, size_t nbytes,
+				    loff_t off)
+{
+	return cpu_uclamp_write(of, buf, nbytes, off, UCLAMP_MIN);
+}
+
+static ssize_t cpu_uclamp_max_write(struct kernfs_open_file *of,
+				    char *buf, size_t nbytes,
+				    loff_t off)
+{
+	return cpu_uclamp_write(of, buf, nbytes, off, UCLAMP_MAX);
+}
+
+static inline void cpu_uclamp_print(struct seq_file *sf,
+				    enum uclamp_id clamp_id)
+{
+	struct task_group *tg;
+	u64 util_clamp;
+	u64 percent;
+	u32 rem;
+
+	rcu_read_lock();
+	tg = css_tg(seq_css(sf));
+	util_clamp = tg->uclamp_req[clamp_id].value;
+	rcu_read_unlock();
+
+	if (util_clamp == SCHED_CAPACITY_SCALE) {
+		seq_puts(sf, "max\n");
+		return;
+	}
+
+	percent = tg->uclamp_pct[clamp_id];
+	percent = div_u64_rem(percent, POW10(UCLAMP_PERCENT_SHIFT), &rem);
+	seq_printf(sf, "%llu.%0*u\n", percent, UCLAMP_PERCENT_SHIFT, rem);
+}
+
+static int cpu_uclamp_min_show(struct seq_file *sf, void *v)
+{
+	cpu_uclamp_print(sf, UCLAMP_MIN);
+	return 0;
+}
+
+static int cpu_uclamp_max_show(struct seq_file *sf, void *v)
+{
+	cpu_uclamp_print(sf, UCLAMP_MAX);
+	return 0;
+}
+#endif /* CONFIG_UCLAMP_TASK_GROUP */
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static int cpu_shares_write_u64(struct cgroup_subsys_state *css,
+				struct cftype *cftype, u64 shareval)
+{
+	if (shareval > scale_load_down(ULONG_MAX))
+		shareval = MAX_SHARES;
+	return sched_group_set_shares(css_tg(css), scale_load(shareval));
+}
+
+static u64 cpu_shares_read_u64(struct cgroup_subsys_state *css,
+			       struct cftype *cft)
+{
+	struct task_group *tg = css_tg(css);
+
+	return (u64) scale_load_down(tg->shares);
+}
+
+#ifdef CONFIG_CFS_BANDWIDTH
+static DEFINE_MUTEX(cfs_constraints_mutex);
+
+const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */
+static const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */
+/* More than 203 days if BW_SHIFT equals 20. */
+static const u64 max_cfs_runtime = MAX_BW * NSEC_PER_USEC;
+
+static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime);
+
+static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota,
+				u64 burst)
+{
+	int i, ret = 0, runtime_enabled, runtime_was_enabled;
+	struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
+
+	if (tg == &root_task_group)
+		return -EINVAL;
+
+	/*
+	 * Ensure we have at some amount of bandwidth every period.  This is
+	 * to prevent reaching a state of large arrears when throttled via
+	 * entity_tick() resulting in prolonged exit starvation.
+	 */
+	if (quota < min_cfs_quota_period || period < min_cfs_quota_period)
+		return -EINVAL;
+
+	/*
+	 * Likewise, bound things on the other side by preventing insane quota
+	 * periods.  This also allows us to normalize in computing quota
+	 * feasibility.
+	 */
+	if (period > max_cfs_quota_period)
+		return -EINVAL;
+
+	/*
+	 * Bound quota to defend quota against overflow during bandwidth shift.
+	 */
+	if (quota != RUNTIME_INF && quota > max_cfs_runtime)
+		return -EINVAL;
+
+	if (quota != RUNTIME_INF && (burst > quota ||
+				     burst + quota > max_cfs_runtime))
+		return -EINVAL;
+
+	/*
+	 * Prevent race between setting of cfs_rq->runtime_enabled and
+	 * unthrottle_offline_cfs_rqs().
+	 */
+	cpus_read_lock();
+	mutex_lock(&cfs_constraints_mutex);
+	ret = __cfs_schedulable(tg, period, quota);
+	if (ret)
+		goto out_unlock;
+
+	runtime_enabled = quota != RUNTIME_INF;
+	runtime_was_enabled = cfs_b->quota != RUNTIME_INF;
+	/*
+	 * If we need to toggle cfs_bandwidth_used, off->on must occur
+	 * before making related changes, and on->off must occur afterwards
+	 */
+	if (runtime_enabled && !runtime_was_enabled)
+		cfs_bandwidth_usage_inc();
+	raw_spin_lock_irq(&cfs_b->lock);
+	cfs_b->period = ns_to_ktime(period);
+	cfs_b->quota = quota;
+	cfs_b->burst = burst;
+
+	__refill_cfs_bandwidth_runtime(cfs_b);
+
+	/* Restart the period timer (if active) to handle new period expiry: */
+	if (runtime_enabled)
+		start_cfs_bandwidth(cfs_b);
+
+	raw_spin_unlock_irq(&cfs_b->lock);
+
+	for_each_online_cpu(i) {
+		struct cfs_rq *cfs_rq = tg->cfs_rq[i];
+		struct rq *rq = cfs_rq->rq;
+		struct rq_flags rf;
+
+		rq_lock_irq(rq, &rf);
+		cfs_rq->runtime_enabled = runtime_enabled;
+		cfs_rq->runtime_remaining = 0;
+
+		if (cfs_rq->throttled)
+			unthrottle_cfs_rq(cfs_rq);
+		rq_unlock_irq(rq, &rf);
+	}
+	if (runtime_was_enabled && !runtime_enabled)
+		cfs_bandwidth_usage_dec();
+out_unlock:
+	mutex_unlock(&cfs_constraints_mutex);
+	cpus_read_unlock();
+
+	return ret;
+}
+
+static int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us)
+{
+	u64 quota, period, burst;
+
+	period = ktime_to_ns(tg->cfs_bandwidth.period);
+	burst = tg->cfs_bandwidth.burst;
+	if (cfs_quota_us < 0)
+		quota = RUNTIME_INF;
+	else if ((u64)cfs_quota_us <= U64_MAX / NSEC_PER_USEC)
+		quota = (u64)cfs_quota_us * NSEC_PER_USEC;
+	else
+		return -EINVAL;
+
+	return tg_set_cfs_bandwidth(tg, period, quota, burst);
+}
+
+static long tg_get_cfs_quota(struct task_group *tg)
+{
+	u64 quota_us;
+
+	if (tg->cfs_bandwidth.quota == RUNTIME_INF)
+		return -1;
+
+	quota_us = tg->cfs_bandwidth.quota;
+	do_div(quota_us, NSEC_PER_USEC);
+
+	return quota_us;
+}
+
+static int tg_set_cfs_period(struct task_group *tg, long cfs_period_us)
+{
+	u64 quota, period, burst;
+
+	if ((u64)cfs_period_us > U64_MAX / NSEC_PER_USEC)
+		return -EINVAL;
+
+	period = (u64)cfs_period_us * NSEC_PER_USEC;
+	quota = tg->cfs_bandwidth.quota;
+	burst = tg->cfs_bandwidth.burst;
+
+	return tg_set_cfs_bandwidth(tg, period, quota, burst);
+}
+
+static long tg_get_cfs_period(struct task_group *tg)
+{
+	u64 cfs_period_us;
+
+	cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period);
+	do_div(cfs_period_us, NSEC_PER_USEC);
+
+	return cfs_period_us;
+}
+
+static int tg_set_cfs_burst(struct task_group *tg, long cfs_burst_us)
+{
+	u64 quota, period, burst;
+
+	if ((u64)cfs_burst_us > U64_MAX / NSEC_PER_USEC)
+		return -EINVAL;
+
+	burst = (u64)cfs_burst_us * NSEC_PER_USEC;
+	period = ktime_to_ns(tg->cfs_bandwidth.period);
+	quota = tg->cfs_bandwidth.quota;
+
+	return tg_set_cfs_bandwidth(tg, period, quota, burst);
+}
+
+static long tg_get_cfs_burst(struct task_group *tg)
+{
+	u64 burst_us;
+
+	burst_us = tg->cfs_bandwidth.burst;
+	do_div(burst_us, NSEC_PER_USEC);
+
+	return burst_us;
+}
+
+static s64 cpu_cfs_quota_read_s64(struct cgroup_subsys_state *css,
+				  struct cftype *cft)
+{
+	return tg_get_cfs_quota(css_tg(css));
+}
+
+static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state *css,
+				   struct cftype *cftype, s64 cfs_quota_us)
+{
+	return tg_set_cfs_quota(css_tg(css), cfs_quota_us);
+}
+
+static u64 cpu_cfs_period_read_u64(struct cgroup_subsys_state *css,
+				   struct cftype *cft)
+{
+	return tg_get_cfs_period(css_tg(css));
+}
+
+static int cpu_cfs_period_write_u64(struct cgroup_subsys_state *css,
+				    struct cftype *cftype, u64 cfs_period_us)
+{
+	return tg_set_cfs_period(css_tg(css), cfs_period_us);
+}
+
+static u64 cpu_cfs_burst_read_u64(struct cgroup_subsys_state *css,
+				  struct cftype *cft)
+{
+	return tg_get_cfs_burst(css_tg(css));
+}
+
+static int cpu_cfs_burst_write_u64(struct cgroup_subsys_state *css,
+				   struct cftype *cftype, u64 cfs_burst_us)
+{
+	return tg_set_cfs_burst(css_tg(css), cfs_burst_us);
+}
+
+struct cfs_schedulable_data {
+	struct task_group *tg;
+	u64 period, quota;
+};
+
+/*
+ * normalize group quota/period to be quota/max_period
+ * note: units are usecs
+ */
+static u64 normalize_cfs_quota(struct task_group *tg,
+			       struct cfs_schedulable_data *d)
+{
+	u64 quota, period;
+
+	if (tg == d->tg) {
+		period = d->period;
+		quota = d->quota;
+	} else {
+		period = tg_get_cfs_period(tg);
+		quota = tg_get_cfs_quota(tg);
+	}
+
+	/* note: these should typically be equivalent */
+	if (quota == RUNTIME_INF || quota == -1)
+		return RUNTIME_INF;
+
+	return to_ratio(period, quota);
+}
+
+static int tg_cfs_schedulable_down(struct task_group *tg, void *data)
+{
+	struct cfs_schedulable_data *d = data;
+	struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
+	s64 quota = 0, parent_quota = -1;
+
+	if (!tg->parent) {
+		quota = RUNTIME_INF;
+	} else {
+		struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth;
+
+		quota = normalize_cfs_quota(tg, d);
+		parent_quota = parent_b->hierarchical_quota;
+
+		/*
+		 * Ensure max(child_quota) <= parent_quota.  On cgroup2,
+		 * always take the non-RUNTIME_INF min.  On cgroup1, only
+		 * inherit when no limit is set. In both cases this is used
+		 * by the scheduler to determine if a given CFS task has a
+		 * bandwidth constraint at some higher level.
+		 */
+		if (cgroup_subsys_on_dfl(cpu_cgrp_subsys)) {
+			if (quota == RUNTIME_INF)
+				quota = parent_quota;
+			else if (parent_quota != RUNTIME_INF)
+				quota = min(quota, parent_quota);
+		} else {
+			if (quota == RUNTIME_INF)
+				quota = parent_quota;
+			else if (parent_quota != RUNTIME_INF && quota > parent_quota)
+				return -EINVAL;
+		}
+	}
+	cfs_b->hierarchical_quota = quota;
+
+	return 0;
+}
+
+static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota)
+{
+	int ret;
+	struct cfs_schedulable_data data = {
+		.tg = tg,
+		.period = period,
+		.quota = quota,
+	};
+
+	if (quota != RUNTIME_INF) {
+		do_div(data.period, NSEC_PER_USEC);
+		do_div(data.quota, NSEC_PER_USEC);
+	}
+
+	rcu_read_lock();
+	ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data);
+	rcu_read_unlock();
+
+	return ret;
+}
+
+static int cpu_cfs_stat_show(struct seq_file *sf, void *v)
+{
+	struct task_group *tg = css_tg(seq_css(sf));
+	struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
+
+	seq_printf(sf, "nr_periods %d\n", cfs_b->nr_periods);
+	seq_printf(sf, "nr_throttled %d\n", cfs_b->nr_throttled);
+	seq_printf(sf, "throttled_time %llu\n", cfs_b->throttled_time);
+
+	if (schedstat_enabled() && tg != &root_task_group) {
+		struct sched_statistics *stats;
+		u64 ws = 0;
+		int i;
+
+		for_each_possible_cpu(i) {
+			stats = __schedstats_from_se(tg->se[i]);
+			ws += schedstat_val(stats->wait_sum);
+		}
+
+		seq_printf(sf, "wait_sum %llu\n", ws);
+	}
+
+	seq_printf(sf, "nr_bursts %d\n", cfs_b->nr_burst);
+	seq_printf(sf, "burst_time %llu\n", cfs_b->burst_time);
+
+	return 0;
+}
+
+static u64 throttled_time_self(struct task_group *tg)
+{
+	int i;
+	u64 total = 0;
+
+	for_each_possible_cpu(i) {
+		total += READ_ONCE(tg->cfs_rq[i]->throttled_clock_self_time);
+	}
+
+	return total;
+}
+
+static int cpu_cfs_local_stat_show(struct seq_file *sf, void *v)
+{
+	struct task_group *tg = css_tg(seq_css(sf));
+
+	seq_printf(sf, "throttled_time %llu\n", throttled_time_self(tg));
+
+	return 0;
+}
+#endif /* CONFIG_CFS_BANDWIDTH */
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+#ifdef CONFIG_RT_GROUP_SCHED
+static int cpu_rt_runtime_write(struct cgroup_subsys_state *css,
+				struct cftype *cft, s64 val)
+{
+	return sched_group_set_rt_runtime(css_tg(css), val);
+}
+
+static s64 cpu_rt_runtime_read(struct cgroup_subsys_state *css,
+			       struct cftype *cft)
+{
+	return sched_group_rt_runtime(css_tg(css));
+}
+
+static int cpu_rt_period_write_uint(struct cgroup_subsys_state *css,
+				    struct cftype *cftype, u64 rt_period_us)
+{
+	return sched_group_set_rt_period(css_tg(css), rt_period_us);
+}
+
+static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css,
+				   struct cftype *cft)
+{
+	return sched_group_rt_period(css_tg(css));
+}
+#endif /* CONFIG_RT_GROUP_SCHED */
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static s64 cpu_idle_read_s64(struct cgroup_subsys_state *css,
+			       struct cftype *cft)
+{
+	return css_tg(css)->idle;
+}
+
+static int cpu_idle_write_s64(struct cgroup_subsys_state *css,
+				struct cftype *cft, s64 idle)
+{
+	return sched_group_set_idle(css_tg(css), idle);
+}
+#endif
+
+static struct cftype cpu_legacy_files[] = {
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	{
+		.name = "shares",
+		.read_u64 = cpu_shares_read_u64,
+		.write_u64 = cpu_shares_write_u64,
+	},
+	{
+		.name = "idle",
+		.read_s64 = cpu_idle_read_s64,
+		.write_s64 = cpu_idle_write_s64,
+	},
+#endif
+#ifdef CONFIG_CFS_BANDWIDTH
+	{
+		.name = "cfs_quota_us",
+		.read_s64 = cpu_cfs_quota_read_s64,
+		.write_s64 = cpu_cfs_quota_write_s64,
+	},
+	{
+		.name = "cfs_period_us",
+		.read_u64 = cpu_cfs_period_read_u64,
+		.write_u64 = cpu_cfs_period_write_u64,
+	},
+	{
+		.name = "cfs_burst_us",
+		.read_u64 = cpu_cfs_burst_read_u64,
+		.write_u64 = cpu_cfs_burst_write_u64,
+	},
+	{
+		.name = "stat",
+		.seq_show = cpu_cfs_stat_show,
+	},
+	{
+		.name = "stat.local",
+		.seq_show = cpu_cfs_local_stat_show,
+	},
+#endif
+#ifdef CONFIG_RT_GROUP_SCHED
+	{
+		.name = "rt_runtime_us",
+		.read_s64 = cpu_rt_runtime_read,
+		.write_s64 = cpu_rt_runtime_write,
+	},
+	{
+		.name = "rt_period_us",
+		.read_u64 = cpu_rt_period_read_uint,
+		.write_u64 = cpu_rt_period_write_uint,
+	},
+#endif
+#ifdef CONFIG_UCLAMP_TASK_GROUP
+	{
+		.name = "uclamp.min",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.seq_show = cpu_uclamp_min_show,
+		.write = cpu_uclamp_min_write,
+	},
+	{
+		.name = "uclamp.max",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.seq_show = cpu_uclamp_max_show,
+		.write = cpu_uclamp_max_write,
+	},
+#endif
+	{ }	/* Terminate */
+};
+
+static int cpu_extra_stat_show(struct seq_file *sf,
+			       struct cgroup_subsys_state *css)
+{
+#ifdef CONFIG_CFS_BANDWIDTH
+	{
+		struct task_group *tg = css_tg(css);
+		struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
+		u64 throttled_usec, burst_usec;
+
+		throttled_usec = cfs_b->throttled_time;
+		do_div(throttled_usec, NSEC_PER_USEC);
+		burst_usec = cfs_b->burst_time;
+		do_div(burst_usec, NSEC_PER_USEC);
+
+		seq_printf(sf, "nr_periods %d\n"
+			   "nr_throttled %d\n"
+			   "throttled_usec %llu\n"
+			   "nr_bursts %d\n"
+			   "burst_usec %llu\n",
+			   cfs_b->nr_periods, cfs_b->nr_throttled,
+			   throttled_usec, cfs_b->nr_burst, burst_usec);
+	}
+#endif
+	return 0;
+}
+
+static int cpu_local_stat_show(struct seq_file *sf,
+			       struct cgroup_subsys_state *css)
+{
+#ifdef CONFIG_CFS_BANDWIDTH
+	{
+		struct task_group *tg = css_tg(css);
+		u64 throttled_self_usec;
+
+		throttled_self_usec = throttled_time_self(tg);
+		do_div(throttled_self_usec, NSEC_PER_USEC);
+
+		seq_printf(sf, "throttled_usec %llu\n",
+			   throttled_self_usec);
+	}
+#endif
+	return 0;
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static u64 cpu_weight_read_u64(struct cgroup_subsys_state *css,
+			       struct cftype *cft)
+{
+	struct task_group *tg = css_tg(css);
+	u64 weight = scale_load_down(tg->shares);
+
+	return DIV_ROUND_CLOSEST_ULL(weight * CGROUP_WEIGHT_DFL, 1024);
+}
+
+static int cpu_weight_write_u64(struct cgroup_subsys_state *css,
+				struct cftype *cft, u64 weight)
+{
+	/*
+	 * cgroup weight knobs should use the common MIN, DFL and MAX
+	 * values which are 1, 100 and 10000 respectively.  While it loses
+	 * a bit of range on both ends, it maps pretty well onto the shares
+	 * value used by scheduler and the round-trip conversions preserve
+	 * the original value over the entire range.
+	 */
+	if (weight < CGROUP_WEIGHT_MIN || weight > CGROUP_WEIGHT_MAX)
+		return -ERANGE;
+
+	weight = DIV_ROUND_CLOSEST_ULL(weight * 1024, CGROUP_WEIGHT_DFL);
+
+	return sched_group_set_shares(css_tg(css), scale_load(weight));
+}
+
+static s64 cpu_weight_nice_read_s64(struct cgroup_subsys_state *css,
+				    struct cftype *cft)
+{
+	unsigned long weight = scale_load_down(css_tg(css)->shares);
+	int last_delta = INT_MAX;
+	int prio, delta;
+
+	/* find the closest nice value to the current weight */
+	for (prio = 0; prio < ARRAY_SIZE(sched_prio_to_weight); prio++) {
+		delta = abs(sched_prio_to_weight[prio] - weight);
+		if (delta >= last_delta)
+			break;
+		last_delta = delta;
+	}
+
+	return PRIO_TO_NICE(prio - 1 + MAX_RT_PRIO);
+}
+
+static int cpu_weight_nice_write_s64(struct cgroup_subsys_state *css,
+				     struct cftype *cft, s64 nice)
+{
+	unsigned long weight;
+	int idx;
+
+	if (nice < MIN_NICE || nice > MAX_NICE)
+		return -ERANGE;
+
+	idx = NICE_TO_PRIO(nice) - MAX_RT_PRIO;
+	idx = array_index_nospec(idx, 40);
+	weight = sched_prio_to_weight[idx];
+
+	return sched_group_set_shares(css_tg(css), scale_load(weight));
+}
+#endif
+
+static void __maybe_unused cpu_period_quota_print(struct seq_file *sf,
+						  long period, long quota)
+{
+	if (quota < 0)
+		seq_puts(sf, "max");
+	else
+		seq_printf(sf, "%ld", quota);
+
+	seq_printf(sf, " %ld\n", period);
+}
+
+/* caller should put the current value in *@periodp before calling */
+static int __maybe_unused cpu_period_quota_parse(char *buf,
+						 u64 *periodp, u64 *quotap)
+{
+	char tok[21];	/* U64_MAX */
+
+	if (sscanf(buf, "%20s %llu", tok, periodp) < 1)
+		return -EINVAL;
+
+	*periodp *= NSEC_PER_USEC;
+
+	if (sscanf(tok, "%llu", quotap))
+		*quotap *= NSEC_PER_USEC;
+	else if (!strcmp(tok, "max"))
+		*quotap = RUNTIME_INF;
+	else
+		return -EINVAL;
+
+	return 0;
+}
+
+#ifdef CONFIG_CFS_BANDWIDTH
+static int cpu_max_show(struct seq_file *sf, void *v)
+{
+	struct task_group *tg = css_tg(seq_css(sf));
+
+	cpu_period_quota_print(sf, tg_get_cfs_period(tg), tg_get_cfs_quota(tg));
+	return 0;
+}
+
+static ssize_t cpu_max_write(struct kernfs_open_file *of,
+			     char *buf, size_t nbytes, loff_t off)
+{
+	struct task_group *tg = css_tg(of_css(of));
+	u64 period = tg_get_cfs_period(tg);
+	u64 burst = tg_get_cfs_burst(tg);
+	u64 quota;
+	int ret;
+
+	ret = cpu_period_quota_parse(buf, &period, &quota);
+	if (!ret)
+		ret = tg_set_cfs_bandwidth(tg, period, quota, burst);
+	return ret ?: nbytes;
+}
+#endif
+
+static struct cftype cpu_files[] = {
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	{
+		.name = "weight",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.read_u64 = cpu_weight_read_u64,
+		.write_u64 = cpu_weight_write_u64,
+	},
+	{
+		.name = "weight.nice",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.read_s64 = cpu_weight_nice_read_s64,
+		.write_s64 = cpu_weight_nice_write_s64,
+	},
+	{
+		.name = "idle",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.read_s64 = cpu_idle_read_s64,
+		.write_s64 = cpu_idle_write_s64,
+	},
+#endif
+#ifdef CONFIG_CFS_BANDWIDTH
+	{
+		.name = "max",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.seq_show = cpu_max_show,
+		.write = cpu_max_write,
+	},
+	{
+		.name = "max.burst",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.read_u64 = cpu_cfs_burst_read_u64,
+		.write_u64 = cpu_cfs_burst_write_u64,
+	},
+#endif
+#ifdef CONFIG_UCLAMP_TASK_GROUP
+	{
+		.name = "uclamp.min",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.seq_show = cpu_uclamp_min_show,
+		.write = cpu_uclamp_min_write,
+	},
+	{
+		.name = "uclamp.max",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.seq_show = cpu_uclamp_max_show,
+		.write = cpu_uclamp_max_write,
+	},
+#endif
+	{ }	/* terminate */
+};
+
+struct cgroup_subsys cpu_cgrp_subsys = {
+	.css_alloc	= cpu_cgroup_css_alloc,
+	.css_online	= cpu_cgroup_css_online,
+	.css_released	= cpu_cgroup_css_released,
+	.css_free	= cpu_cgroup_css_free,
+	.css_extra_stat_show = cpu_extra_stat_show,
+	.css_local_stat_show = cpu_local_stat_show,
+#ifdef CONFIG_RT_GROUP_SCHED
+	.can_attach	= cpu_cgroup_can_attach,
+#endif
+	.attach		= cpu_cgroup_attach,
+	.legacy_cftypes	= cpu_legacy_files,
+	.dfl_cftypes	= cpu_files,
+	.early_init	= true,
+	.threaded	= true,
+};
+
+#endif	/* CONFIG_CGROUP_SCHED */
+
+void dump_cpu_task(int cpu)
+{
+	if (cpu == smp_processor_id() && in_hardirq()) {
+		struct pt_regs *regs;
+
+		regs = get_irq_regs();
+		if (regs) {
+			show_regs(regs);
+			return;
+		}
+	}
+
+	if (trigger_single_cpu_backtrace(cpu))
+		return;
+
+	pr_info("Task dump for CPU %d:\n", cpu);
+	sched_show_task(cpu_curr(cpu));
+}
+
+/*
+ * Nice levels are multiplicative, with a gentle 10% change for every
+ * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
+ * nice 1, it will get ~10% less CPU time than another CPU-bound task
+ * that remained on nice 0.
+ *
+ * The "10% effect" is relative and cumulative: from _any_ nice level,
+ * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
+ * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
+ * If a task goes up by ~10% and another task goes down by ~10% then
+ * the relative distance between them is ~25%.)
+ */
+const int sched_prio_to_weight[40] = {
+ /* -20 */     88761,     71755,     56483,     46273,     36291,
+ /* -15 */     29154,     23254,     18705,     14949,     11916,
+ /* -10 */      9548,      7620,      6100,      4904,      3906,
+ /*  -5 */      3121,      2501,      1991,      1586,      1277,
+ /*   0 */      1024,       820,       655,       526,       423,
+ /*   5 */       335,       272,       215,       172,       137,
+ /*  10 */       110,        87,        70,        56,        45,
+ /*  15 */        36,        29,        23,        18,        15,
+};
+
+/*
+ * Inverse (2^32/x) values of the sched_prio_to_weight[] array, precalculated.
+ *
+ * In cases where the weight does not change often, we can use the
+ * precalculated inverse to speed up arithmetics by turning divisions
+ * into multiplications:
+ */
+const u32 sched_prio_to_wmult[40] = {
+ /* -20 */     48388,     59856,     76040,     92818,    118348,
+ /* -15 */    147320,    184698,    229616,    287308,    360437,
+ /* -10 */    449829,    563644,    704093,    875809,   1099582,
+ /*  -5 */   1376151,   1717300,   2157191,   2708050,   3363326,
+ /*   0 */   4194304,   5237765,   6557202,   8165337,  10153587,
+ /*   5 */  12820798,  15790321,  19976592,  24970740,  31350126,
+ /*  10 */  39045157,  49367440,  61356676,  76695844,  95443717,
+ /*  15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
+};
+
+void call_trace_sched_update_nr_running(struct rq *rq, int count)
+{
+        trace_sched_update_nr_running_tp(rq, count);
+}
+
+#ifdef CONFIG_SCHED_MM_CID
+
+/*
+ * @cid_lock: Guarantee forward-progress of cid allocation.
+ *
+ * Concurrency ID allocation within a bitmap is mostly lock-free. The cid_lock
+ * is only used when contention is detected by the lock-free allocation so
+ * forward progress can be guaranteed.
+ */
+DEFINE_RAW_SPINLOCK(cid_lock);
+
+/*
+ * @use_cid_lock: Select cid allocation behavior: lock-free vs spinlock.
+ *
+ * When @use_cid_lock is 0, the cid allocation is lock-free. When contention is
+ * detected, it is set to 1 to ensure that all newly coming allocations are
+ * serialized by @cid_lock until the allocation which detected contention
+ * completes and sets @use_cid_lock back to 0. This guarantees forward progress
+ * of a cid allocation.
+ */
+int use_cid_lock;
+
+/*
+ * mm_cid remote-clear implements a lock-free algorithm to clear per-mm/cpu cid
+ * concurrently with respect to the execution of the source runqueue context
+ * switch.
+ *
+ * There is one basic properties we want to guarantee here:
+ *
+ * (1) Remote-clear should _never_ mark a per-cpu cid UNSET when it is actively
+ * used by a task. That would lead to concurrent allocation of the cid and
+ * userspace corruption.
+ *
+ * Provide this guarantee by introducing a Dekker memory ordering to guarantee
+ * that a pair of loads observe at least one of a pair of stores, which can be
+ * shown as:
+ *
+ *      X = Y = 0
+ *
+ *      w[X]=1          w[Y]=1
+ *      MB              MB
+ *      r[Y]=y          r[X]=x
+ *
+ * Which guarantees that x==0 && y==0 is impossible. But rather than using
+ * values 0 and 1, this algorithm cares about specific state transitions of the
+ * runqueue current task (as updated by the scheduler context switch), and the
+ * per-mm/cpu cid value.
+ *
+ * Let's introduce task (Y) which has task->mm == mm and task (N) which has
+ * task->mm != mm for the rest of the discussion. There are two scheduler state
+ * transitions on context switch we care about:
+ *
+ * (TSA) Store to rq->curr with transition from (N) to (Y)
+ *
+ * (TSB) Store to rq->curr with transition from (Y) to (N)
+ *
+ * On the remote-clear side, there is one transition we care about:
+ *
+ * (TMA) cmpxchg to *pcpu_cid to set the LAZY flag
+ *
+ * There is also a transition to UNSET state which can be performed from all
+ * sides (scheduler, remote-clear). It is always performed with a cmpxchg which
+ * guarantees that only a single thread will succeed:
+ *
+ * (TMB) cmpxchg to *pcpu_cid to mark UNSET
+ *
+ * Just to be clear, what we do _not_ want to happen is a transition to UNSET
+ * when a thread is actively using the cid (property (1)).
+ *
+ * Let's looks at the relevant combinations of TSA/TSB, and TMA transitions.
+ *
+ * Scenario A) (TSA)+(TMA) (from next task perspective)
+ *
+ * CPU0                                      CPU1
+ *
+ * Context switch CS-1                       Remote-clear
+ *   - store to rq->curr: (N)->(Y) (TSA)     - cmpxchg to *pcpu_id to LAZY (TMA)
+ *                                             (implied barrier after cmpxchg)
+ *   - switch_mm_cid()
+ *     - memory barrier (see switch_mm_cid()
+ *       comment explaining how this barrier
+ *       is combined with other scheduler
+ *       barriers)
+ *     - mm_cid_get (next)
+ *       - READ_ONCE(*pcpu_cid)              - rcu_dereference(src_rq->curr)
+ *
+ * This Dekker ensures that either task (Y) is observed by the
+ * rcu_dereference() or the LAZY flag is observed by READ_ONCE(), or both are
+ * observed.
+ *
+ * If task (Y) store is observed by rcu_dereference(), it means that there is
+ * still an active task on the cpu. Remote-clear will therefore not transition
+ * to UNSET, which fulfills property (1).
+ *
+ * If task (Y) is not observed, but the lazy flag is observed by READ_ONCE(),
+ * it will move its state to UNSET, which clears the percpu cid perhaps
+ * uselessly (which is not an issue for correctness). Because task (Y) is not
+ * observed, CPU1 can move ahead to set the state to UNSET. Because moving
+ * state to UNSET is done with a cmpxchg expecting that the old state has the
+ * LAZY flag set, only one thread will successfully UNSET.
+ *
+ * If both states (LAZY flag and task (Y)) are observed, the thread on CPU0
+ * will observe the LAZY flag and transition to UNSET (perhaps uselessly), and
+ * CPU1 will observe task (Y) and do nothing more, which is fine.
+ *
+ * What we are effectively preventing with this Dekker is a scenario where
+ * neither LAZY flag nor store (Y) are observed, which would fail property (1)
+ * because this would UNSET a cid which is actively used.
+ */
+
+void sched_mm_cid_migrate_from(struct task_struct *t)
+{
+	t->migrate_from_cpu = task_cpu(t);
+}
+
+static
+int __sched_mm_cid_migrate_from_fetch_cid(struct rq *src_rq,
+					  struct task_struct *t,
+					  struct mm_cid *src_pcpu_cid)
+{
+	struct mm_struct *mm = t->mm;
+	struct task_struct *src_task;
+	int src_cid, last_mm_cid;
+
+	if (!mm)
+		return -1;
+
+	last_mm_cid = t->last_mm_cid;
+	/*
+	 * If the migrated task has no last cid, or if the current
+	 * task on src rq uses the cid, it means the source cid does not need
+	 * to be moved to the destination cpu.
+	 */
+	if (last_mm_cid == -1)
+		return -1;
+	src_cid = READ_ONCE(src_pcpu_cid->cid);
+	if (!mm_cid_is_valid(src_cid) || last_mm_cid != src_cid)
+		return -1;
+
+	/*
+	 * If we observe an active task using the mm on this rq, it means we
+	 * are not the last task to be migrated from this cpu for this mm, so
+	 * there is no need to move src_cid to the destination cpu.
+	 */
+	rcu_read_lock();
+	src_task = rcu_dereference(src_rq->curr);
+	if (READ_ONCE(src_task->mm_cid_active) && src_task->mm == mm) {
+		rcu_read_unlock();
+		t->last_mm_cid = -1;
+		return -1;
+	}
+	rcu_read_unlock();
+
+	return src_cid;
+}
+
+static
+int __sched_mm_cid_migrate_from_try_steal_cid(struct rq *src_rq,
+					      struct task_struct *t,
+					      struct mm_cid *src_pcpu_cid,
+					      int src_cid)
+{
+	struct task_struct *src_task;
+	struct mm_struct *mm = t->mm;
+	int lazy_cid;
+
+	if (src_cid == -1)
+		return -1;
+
+	/*
+	 * Attempt to clear the source cpu cid to move it to the destination
+	 * cpu.
+	 */
+	lazy_cid = mm_cid_set_lazy_put(src_cid);
+	if (!try_cmpxchg(&src_pcpu_cid->cid, &src_cid, lazy_cid))
+		return -1;
+
+	/*
+	 * The implicit barrier after cmpxchg per-mm/cpu cid before loading
+	 * rq->curr->mm matches the scheduler barrier in context_switch()
+	 * between store to rq->curr and load of prev and next task's
+	 * per-mm/cpu cid.
+	 *
+	 * The implicit barrier after cmpxchg per-mm/cpu cid before loading
+	 * rq->curr->mm_cid_active matches the barrier in
+	 * sched_mm_cid_exit_signals(), sched_mm_cid_before_execve(), and
+	 * sched_mm_cid_after_execve() between store to t->mm_cid_active and
+	 * load of per-mm/cpu cid.
+	 */
+
+	/*
+	 * If we observe an active task using the mm on this rq after setting
+	 * the lazy-put flag, this task will be responsible for transitioning
+	 * from lazy-put flag set to MM_CID_UNSET.
+	 */
+	rcu_read_lock();
+	src_task = rcu_dereference(src_rq->curr);
+	if (READ_ONCE(src_task->mm_cid_active) && src_task->mm == mm) {
+		rcu_read_unlock();
+		/*
+		 * We observed an active task for this mm, there is therefore
+		 * no point in moving this cid to the destination cpu.
+		 */
+		t->last_mm_cid = -1;
+		return -1;
+	}
+	rcu_read_unlock();
+
+	/*
+	 * The src_cid is unused, so it can be unset.
+	 */
+	if (!try_cmpxchg(&src_pcpu_cid->cid, &lazy_cid, MM_CID_UNSET))
+		return -1;
+	return src_cid;
+}
+
+/*
+ * Migration to dst cpu. Called with dst_rq lock held.
+ * Interrupts are disabled, which keeps the window of cid ownership without the
+ * source rq lock held small.
+ */
+void sched_mm_cid_migrate_to(struct rq *dst_rq, struct task_struct *t)
+{
+	struct mm_cid *src_pcpu_cid, *dst_pcpu_cid;
+	struct mm_struct *mm = t->mm;
+	int src_cid, dst_cid, src_cpu;
+	struct rq *src_rq;
+
+	lockdep_assert_rq_held(dst_rq);
+
+	if (!mm)
+		return;
+	src_cpu = t->migrate_from_cpu;
+	if (src_cpu == -1) {
+		t->last_mm_cid = -1;
+		return;
+	}
+	/*
+	 * Move the src cid if the dst cid is unset. This keeps id
+	 * allocation closest to 0 in cases where few threads migrate around
+	 * many cpus.
+	 *
+	 * If destination cid is already set, we may have to just clear
+	 * the src cid to ensure compactness in frequent migrations
+	 * scenarios.
+	 *
+	 * It is not useful to clear the src cid when the number of threads is
+	 * greater or equal to the number of allowed cpus, because user-space
+	 * can expect that the number of allowed cids can reach the number of
+	 * allowed cpus.
+	 */
+	dst_pcpu_cid = per_cpu_ptr(mm->pcpu_cid, cpu_of(dst_rq));
+	dst_cid = READ_ONCE(dst_pcpu_cid->cid);
+	if (!mm_cid_is_unset(dst_cid) &&
+	    atomic_read(&mm->mm_users) >= t->nr_cpus_allowed)
+		return;
+	src_pcpu_cid = per_cpu_ptr(mm->pcpu_cid, src_cpu);
+	src_rq = cpu_rq(src_cpu);
+	src_cid = __sched_mm_cid_migrate_from_fetch_cid(src_rq, t, src_pcpu_cid);
+	if (src_cid == -1)
+		return;
+	src_cid = __sched_mm_cid_migrate_from_try_steal_cid(src_rq, t, src_pcpu_cid,
+							    src_cid);
+	if (src_cid == -1)
+		return;
+	if (!mm_cid_is_unset(dst_cid)) {
+		__mm_cid_put(mm, src_cid);
+		return;
+	}
+	/* Move src_cid to dst cpu. */
+	mm_cid_snapshot_time(dst_rq, mm);
+	WRITE_ONCE(dst_pcpu_cid->cid, src_cid);
+}
+
+static void sched_mm_cid_remote_clear(struct mm_struct *mm, struct mm_cid *pcpu_cid,
+				      int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	struct task_struct *t;
+	unsigned long flags;
+	int cid, lazy_cid;
+
+	cid = READ_ONCE(pcpu_cid->cid);
+	if (!mm_cid_is_valid(cid))
+		return;
+
+	/*
+	 * Clear the cpu cid if it is set to keep cid allocation compact.  If
+	 * there happens to be other tasks left on the source cpu using this
+	 * mm, the next task using this mm will reallocate its cid on context
+	 * switch.
+	 */
+	lazy_cid = mm_cid_set_lazy_put(cid);
+	if (!try_cmpxchg(&pcpu_cid->cid, &cid, lazy_cid))
+		return;
+
+	/*
+	 * The implicit barrier after cmpxchg per-mm/cpu cid before loading
+	 * rq->curr->mm matches the scheduler barrier in context_switch()
+	 * between store to rq->curr and load of prev and next task's
+	 * per-mm/cpu cid.
+	 *
+	 * The implicit barrier after cmpxchg per-mm/cpu cid before loading
+	 * rq->curr->mm_cid_active matches the barrier in
+	 * sched_mm_cid_exit_signals(), sched_mm_cid_before_execve(), and
+	 * sched_mm_cid_after_execve() between store to t->mm_cid_active and
+	 * load of per-mm/cpu cid.
+	 */
+
+	/*
+	 * If we observe an active task using the mm on this rq after setting
+	 * the lazy-put flag, that task will be responsible for transitioning
+	 * from lazy-put flag set to MM_CID_UNSET.
+	 */
+	rcu_read_lock();
+	t = rcu_dereference(rq->curr);
+	if (READ_ONCE(t->mm_cid_active) && t->mm == mm) {
+		rcu_read_unlock();
+		return;
+	}
+	rcu_read_unlock();
+
+	/*
+	 * The cid is unused, so it can be unset.
+	 * Disable interrupts to keep the window of cid ownership without rq
+	 * lock small.
+	 */
+	local_irq_save(flags);
+	if (try_cmpxchg(&pcpu_cid->cid, &lazy_cid, MM_CID_UNSET))
+		__mm_cid_put(mm, cid);
+	local_irq_restore(flags);
+}
+
+static void sched_mm_cid_remote_clear_old(struct mm_struct *mm, int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	struct mm_cid *pcpu_cid;
+	struct task_struct *curr;
+	u64 rq_clock;
+
+	/*
+	 * rq->clock load is racy on 32-bit but one spurious clear once in a
+	 * while is irrelevant.
+	 */
+	rq_clock = READ_ONCE(rq->clock);
+	pcpu_cid = per_cpu_ptr(mm->pcpu_cid, cpu);
+
+	/*
+	 * In order to take care of infrequently scheduled tasks, bump the time
+	 * snapshot associated with this cid if an active task using the mm is
+	 * observed on this rq.
+	 */
+	rcu_read_lock();
+	curr = rcu_dereference(rq->curr);
+	if (READ_ONCE(curr->mm_cid_active) && curr->mm == mm) {
+		WRITE_ONCE(pcpu_cid->time, rq_clock);
+		rcu_read_unlock();
+		return;
+	}
+	rcu_read_unlock();
+
+	if (rq_clock < pcpu_cid->time + SCHED_MM_CID_PERIOD_NS)
+		return;
+	sched_mm_cid_remote_clear(mm, pcpu_cid, cpu);
+}
+
+static void sched_mm_cid_remote_clear_weight(struct mm_struct *mm, int cpu,
+					     int weight)
+{
+	struct mm_cid *pcpu_cid;
+	int cid;
+
+	pcpu_cid = per_cpu_ptr(mm->pcpu_cid, cpu);
+	cid = READ_ONCE(pcpu_cid->cid);
+	if (!mm_cid_is_valid(cid) || cid < weight)
+		return;
+	sched_mm_cid_remote_clear(mm, pcpu_cid, cpu);
+}
+
+static void task_mm_cid_work(struct callback_head *work)
+{
+	unsigned long now = jiffies, old_scan, next_scan;
+	struct task_struct *t = current;
+	struct cpumask *cidmask;
+	struct mm_struct *mm;
+	int weight, cpu;
+
+	SCHED_WARN_ON(t != container_of(work, struct task_struct, cid_work));
+
+	work->next = work;	/* Prevent double-add */
+	if (t->flags & PF_EXITING)
+		return;
+	mm = t->mm;
+	if (!mm)
+		return;
+	old_scan = READ_ONCE(mm->mm_cid_next_scan);
+	next_scan = now + msecs_to_jiffies(MM_CID_SCAN_DELAY);
+	if (!old_scan) {
+		unsigned long res;
+
+		res = cmpxchg(&mm->mm_cid_next_scan, old_scan, next_scan);
+		if (res != old_scan)
+			old_scan = res;
+		else
+			old_scan = next_scan;
+	}
+	if (time_before(now, old_scan))
+		return;
+	if (!try_cmpxchg(&mm->mm_cid_next_scan, &old_scan, next_scan))
+		return;
+	cidmask = mm_cidmask(mm);
+	/* Clear cids that were not recently used. */
+	for_each_possible_cpu(cpu)
+		sched_mm_cid_remote_clear_old(mm, cpu);
+	weight = cpumask_weight(cidmask);
+	/*
+	 * Clear cids that are greater or equal to the cidmask weight to
+	 * recompact it.
+	 */
+	for_each_possible_cpu(cpu)
+		sched_mm_cid_remote_clear_weight(mm, cpu, weight);
+}
+
+void init_sched_mm_cid(struct task_struct *t)
+{
+	struct mm_struct *mm = t->mm;
+	int mm_users = 0;
+
+	if (mm) {
+		mm_users = atomic_read(&mm->mm_users);
+		if (mm_users == 1)
+			mm->mm_cid_next_scan = jiffies + msecs_to_jiffies(MM_CID_SCAN_DELAY);
+	}
+	t->cid_work.next = &t->cid_work;	/* Protect against double add */
+	init_task_work(&t->cid_work, task_mm_cid_work);
+}
+
+void task_tick_mm_cid(struct rq *rq, struct task_struct *curr)
+{
+	struct callback_head *work = &curr->cid_work;
+	unsigned long now = jiffies;
+
+	if (!curr->mm || (curr->flags & (PF_EXITING | PF_KTHREAD)) ||
+	    work->next != work)
+		return;
+	if (time_before(now, READ_ONCE(curr->mm->mm_cid_next_scan)))
+		return;
+	task_work_add(curr, work, TWA_RESUME);
+}
+
+void sched_mm_cid_exit_signals(struct task_struct *t)
+{
+	struct mm_struct *mm = t->mm;
+	struct rq_flags rf;
+	struct rq *rq;
+
+	if (!mm)
+		return;
+
+	preempt_disable();
+	rq = this_rq();
+	rq_lock_irqsave(rq, &rf);
+	preempt_enable_no_resched();	/* holding spinlock */
+	WRITE_ONCE(t->mm_cid_active, 0);
+	/*
+	 * Store t->mm_cid_active before loading per-mm/cpu cid.
+	 * Matches barrier in sched_mm_cid_remote_clear_old().
+	 */
+	smp_mb();
+	mm_cid_put(mm);
+	t->last_mm_cid = t->mm_cid = -1;
+	rq_unlock_irqrestore(rq, &rf);
+}
+
+void sched_mm_cid_before_execve(struct task_struct *t)
+{
+	struct mm_struct *mm = t->mm;
+	struct rq_flags rf;
+	struct rq *rq;
+
+	if (!mm)
+		return;
+
+	preempt_disable();
+	rq = this_rq();
+	rq_lock_irqsave(rq, &rf);
+	preempt_enable_no_resched();	/* holding spinlock */
+	WRITE_ONCE(t->mm_cid_active, 0);
+	/*
+	 * Store t->mm_cid_active before loading per-mm/cpu cid.
+	 * Matches barrier in sched_mm_cid_remote_clear_old().
+	 */
+	smp_mb();
+	mm_cid_put(mm);
+	t->last_mm_cid = t->mm_cid = -1;
+	rq_unlock_irqrestore(rq, &rf);
+}
+
+void sched_mm_cid_after_execve(struct task_struct *t)
+{
+	struct mm_struct *mm = t->mm;
+	struct rq_flags rf;
+	struct rq *rq;
+
+	if (!mm)
+		return;
+
+	preempt_disable();
+	rq = this_rq();
+	rq_lock_irqsave(rq, &rf);
+	preempt_enable_no_resched();	/* holding spinlock */
+	WRITE_ONCE(t->mm_cid_active, 1);
+	/*
+	 * Store t->mm_cid_active before loading per-mm/cpu cid.
+	 * Matches barrier in sched_mm_cid_remote_clear_old().
+	 */
+	smp_mb();
+	t->last_mm_cid = t->mm_cid = mm_cid_get(rq, mm);
+	rq_unlock_irqrestore(rq, &rf);
+	rseq_set_notify_resume(t);
+}
+
+void sched_mm_cid_fork(struct task_struct *t)
+{
+	WARN_ON_ONCE(!t->mm || t->mm_cid != -1);
+	t->mm_cid_active = 1;
+}
+#endif
diff --git a/kernel/sched/core_sched.c b/kernel/sched/core_sched.c
new file mode 100644
index 0000000000..a57fd8f274
--- /dev/null
+++ b/kernel/sched/core_sched.c
@@ -0,0 +1,300 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ * A simple wrapper around refcount. An allocated sched_core_cookie's
+ * address is used to compute the cookie of the task.
+ */
+struct sched_core_cookie {
+	refcount_t refcnt;
+};
+
+static unsigned long sched_core_alloc_cookie(void)
+{
+	struct sched_core_cookie *ck = kmalloc(sizeof(*ck), GFP_KERNEL);
+	if (!ck)
+		return 0;
+
+	refcount_set(&ck->refcnt, 1);
+	sched_core_get();
+
+	return (unsigned long)ck;
+}
+
+static void sched_core_put_cookie(unsigned long cookie)
+{
+	struct sched_core_cookie *ptr = (void *)cookie;
+
+	if (ptr && refcount_dec_and_test(&ptr->refcnt)) {
+		kfree(ptr);
+		sched_core_put();
+	}
+}
+
+static unsigned long sched_core_get_cookie(unsigned long cookie)
+{
+	struct sched_core_cookie *ptr = (void *)cookie;
+
+	if (ptr)
+		refcount_inc(&ptr->refcnt);
+
+	return cookie;
+}
+
+/*
+ * sched_core_update_cookie - replace the cookie on a task
+ * @p: the task to update
+ * @cookie: the new cookie
+ *
+ * Effectively exchange the task cookie; caller is responsible for lifetimes on
+ * both ends.
+ *
+ * Returns: the old cookie
+ */
+static unsigned long sched_core_update_cookie(struct task_struct *p,
+					      unsigned long cookie)
+{
+	unsigned long old_cookie;
+	struct rq_flags rf;
+	struct rq *rq;
+
+	rq = task_rq_lock(p, &rf);
+
+	/*
+	 * Since creating a cookie implies sched_core_get(), and we cannot set
+	 * a cookie until after we've created it, similarly, we cannot destroy
+	 * a cookie until after we've removed it, we must have core scheduling
+	 * enabled here.
+	 */
+	SCHED_WARN_ON((p->core_cookie || cookie) && !sched_core_enabled(rq));
+
+	if (sched_core_enqueued(p))
+		sched_core_dequeue(rq, p, DEQUEUE_SAVE);
+
+	old_cookie = p->core_cookie;
+	p->core_cookie = cookie;
+
+	/*
+	 * Consider the cases: !prev_cookie and !cookie.
+	 */
+	if (cookie && task_on_rq_queued(p))
+		sched_core_enqueue(rq, p);
+
+	/*
+	 * If task is currently running, it may not be compatible anymore after
+	 * the cookie change, so enter the scheduler on its CPU to schedule it
+	 * away.
+	 *
+	 * Note that it is possible that as a result of this cookie change, the
+	 * core has now entered/left forced idle state. Defer accounting to the
+	 * next scheduling edge, rather than always forcing a reschedule here.
+	 */
+	if (task_on_cpu(rq, p))
+		resched_curr(rq);
+
+	task_rq_unlock(rq, p, &rf);
+
+	return old_cookie;
+}
+
+static unsigned long sched_core_clone_cookie(struct task_struct *p)
+{
+	unsigned long cookie, flags;
+
+	raw_spin_lock_irqsave(&p->pi_lock, flags);
+	cookie = sched_core_get_cookie(p->core_cookie);
+	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+
+	return cookie;
+}
+
+void sched_core_fork(struct task_struct *p)
+{
+	RB_CLEAR_NODE(&p->core_node);
+	p->core_cookie = sched_core_clone_cookie(current);
+}
+
+void sched_core_free(struct task_struct *p)
+{
+	sched_core_put_cookie(p->core_cookie);
+}
+
+static void __sched_core_set(struct task_struct *p, unsigned long cookie)
+{
+	cookie = sched_core_get_cookie(cookie);
+	cookie = sched_core_update_cookie(p, cookie);
+	sched_core_put_cookie(cookie);
+}
+
+/* Called from prctl interface: PR_SCHED_CORE */
+int sched_core_share_pid(unsigned int cmd, pid_t pid, enum pid_type type,
+			 unsigned long uaddr)
+{
+	unsigned long cookie = 0, id = 0;
+	struct task_struct *task, *p;
+	struct pid *grp;
+	int err = 0;
+
+	if (!static_branch_likely(&sched_smt_present))
+		return -ENODEV;
+
+	BUILD_BUG_ON(PR_SCHED_CORE_SCOPE_THREAD != PIDTYPE_PID);
+	BUILD_BUG_ON(PR_SCHED_CORE_SCOPE_THREAD_GROUP != PIDTYPE_TGID);
+	BUILD_BUG_ON(PR_SCHED_CORE_SCOPE_PROCESS_GROUP != PIDTYPE_PGID);
+
+	if (type > PIDTYPE_PGID || cmd >= PR_SCHED_CORE_MAX || pid < 0 ||
+	    (cmd != PR_SCHED_CORE_GET && uaddr))
+		return -EINVAL;
+
+	rcu_read_lock();
+	if (pid == 0) {
+		task = current;
+	} else {
+		task = find_task_by_vpid(pid);
+		if (!task) {
+			rcu_read_unlock();
+			return -ESRCH;
+		}
+	}
+	get_task_struct(task);
+	rcu_read_unlock();
+
+	/*
+	 * Check if this process has the right to modify the specified
+	 * process. Use the regular "ptrace_may_access()" checks.
+	 */
+	if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) {
+		err = -EPERM;
+		goto out;
+	}
+
+	switch (cmd) {
+	case PR_SCHED_CORE_GET:
+		if (type != PIDTYPE_PID || uaddr & 7) {
+			err = -EINVAL;
+			goto out;
+		}
+		cookie = sched_core_clone_cookie(task);
+		if (cookie) {
+			/* XXX improve ? */
+			ptr_to_hashval((void *)cookie, &id);
+		}
+		err = put_user(id, (u64 __user *)uaddr);
+		goto out;
+
+	case PR_SCHED_CORE_CREATE:
+		cookie = sched_core_alloc_cookie();
+		if (!cookie) {
+			err = -ENOMEM;
+			goto out;
+		}
+		break;
+
+	case PR_SCHED_CORE_SHARE_TO:
+		cookie = sched_core_clone_cookie(current);
+		break;
+
+	case PR_SCHED_CORE_SHARE_FROM:
+		if (type != PIDTYPE_PID) {
+			err = -EINVAL;
+			goto out;
+		}
+		cookie = sched_core_clone_cookie(task);
+		__sched_core_set(current, cookie);
+		goto out;
+
+	default:
+		err = -EINVAL;
+		goto out;
+	}
+
+	if (type == PIDTYPE_PID) {
+		__sched_core_set(task, cookie);
+		goto out;
+	}
+
+	read_lock(&tasklist_lock);
+	grp = task_pid_type(task, type);
+
+	do_each_pid_thread(grp, type, p) {
+		if (!ptrace_may_access(p, PTRACE_MODE_READ_REALCREDS)) {
+			err = -EPERM;
+			goto out_tasklist;
+		}
+	} while_each_pid_thread(grp, type, p);
+
+	do_each_pid_thread(grp, type, p) {
+		__sched_core_set(p, cookie);
+	} while_each_pid_thread(grp, type, p);
+out_tasklist:
+	read_unlock(&tasklist_lock);
+
+out:
+	sched_core_put_cookie(cookie);
+	put_task_struct(task);
+	return err;
+}
+
+#ifdef CONFIG_SCHEDSTATS
+
+/* REQUIRES: rq->core's clock recently updated. */
+void __sched_core_account_forceidle(struct rq *rq)
+{
+	const struct cpumask *smt_mask = cpu_smt_mask(cpu_of(rq));
+	u64 delta, now = rq_clock(rq->core);
+	struct rq *rq_i;
+	struct task_struct *p;
+	int i;
+
+	lockdep_assert_rq_held(rq);
+
+	WARN_ON_ONCE(!rq->core->core_forceidle_count);
+
+	if (rq->core->core_forceidle_start == 0)
+		return;
+
+	delta = now - rq->core->core_forceidle_start;
+	if (unlikely((s64)delta <= 0))
+		return;
+
+	rq->core->core_forceidle_start = now;
+
+	if (WARN_ON_ONCE(!rq->core->core_forceidle_occupation)) {
+		/* can't be forced idle without a running task */
+	} else if (rq->core->core_forceidle_count > 1 ||
+		   rq->core->core_forceidle_occupation > 1) {
+		/*
+		 * For larger SMT configurations, we need to scale the charged
+		 * forced idle amount since there can be more than one forced
+		 * idle sibling and more than one running cookied task.
+		 */
+		delta *= rq->core->core_forceidle_count;
+		delta = div_u64(delta, rq->core->core_forceidle_occupation);
+	}
+
+	for_each_cpu(i, smt_mask) {
+		rq_i = cpu_rq(i);
+		p = rq_i->core_pick ?: rq_i->curr;
+
+		if (p == rq_i->idle)
+			continue;
+
+		/*
+		 * Note: this will account forceidle to the current cpu, even
+		 * if it comes from our SMT sibling.
+		 */
+		__account_forceidle_time(p, delta);
+	}
+}
+
+void __sched_core_tick(struct rq *rq)
+{
+	if (!rq->core->core_forceidle_count)
+		return;
+
+	if (rq != rq->core)
+		update_rq_clock(rq->core);
+
+	__sched_core_account_forceidle(rq);
+}
+
+#endif /* CONFIG_SCHEDSTATS */
diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c
new file mode 100644
index 0000000000..0de9dda099
--- /dev/null
+++ b/kernel/sched/cpuacct.c
@@ -0,0 +1,363 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * CPU accounting code for task groups.
+ *
+ * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
+ * (balbir@in.ibm.com).
+ */
+
+/* Time spent by the tasks of the CPU accounting group executing in ... */
+enum cpuacct_stat_index {
+	CPUACCT_STAT_USER,	/* ... user mode */
+	CPUACCT_STAT_SYSTEM,	/* ... kernel mode */
+
+	CPUACCT_STAT_NSTATS,
+};
+
+static const char * const cpuacct_stat_desc[] = {
+	[CPUACCT_STAT_USER] = "user",
+	[CPUACCT_STAT_SYSTEM] = "system",
+};
+
+/* track CPU usage of a group of tasks and its child groups */
+struct cpuacct {
+	struct cgroup_subsys_state	css;
+	/* cpuusage holds pointer to a u64-type object on every CPU */
+	u64 __percpu	*cpuusage;
+	struct kernel_cpustat __percpu	*cpustat;
+};
+
+static inline struct cpuacct *css_ca(struct cgroup_subsys_state *css)
+{
+	return css ? container_of(css, struct cpuacct, css) : NULL;
+}
+
+/* Return CPU accounting group to which this task belongs */
+static inline struct cpuacct *task_ca(struct task_struct *tsk)
+{
+	return css_ca(task_css(tsk, cpuacct_cgrp_id));
+}
+
+static inline struct cpuacct *parent_ca(struct cpuacct *ca)
+{
+	return css_ca(ca->css.parent);
+}
+
+static DEFINE_PER_CPU(u64, root_cpuacct_cpuusage);
+static struct cpuacct root_cpuacct = {
+	.cpustat	= &kernel_cpustat,
+	.cpuusage	= &root_cpuacct_cpuusage,
+};
+
+/* Create a new CPU accounting group */
+static struct cgroup_subsys_state *
+cpuacct_css_alloc(struct cgroup_subsys_state *parent_css)
+{
+	struct cpuacct *ca;
+
+	if (!parent_css)
+		return &root_cpuacct.css;
+
+	ca = kzalloc(sizeof(*ca), GFP_KERNEL);
+	if (!ca)
+		goto out;
+
+	ca->cpuusage = alloc_percpu(u64);
+	if (!ca->cpuusage)
+		goto out_free_ca;
+
+	ca->cpustat = alloc_percpu(struct kernel_cpustat);
+	if (!ca->cpustat)
+		goto out_free_cpuusage;
+
+	return &ca->css;
+
+out_free_cpuusage:
+	free_percpu(ca->cpuusage);
+out_free_ca:
+	kfree(ca);
+out:
+	return ERR_PTR(-ENOMEM);
+}
+
+/* Destroy an existing CPU accounting group */
+static void cpuacct_css_free(struct cgroup_subsys_state *css)
+{
+	struct cpuacct *ca = css_ca(css);
+
+	free_percpu(ca->cpustat);
+	free_percpu(ca->cpuusage);
+	kfree(ca);
+}
+
+static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu,
+				 enum cpuacct_stat_index index)
+{
+	u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
+	u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat;
+	u64 data;
+
+	/*
+	 * We allow index == CPUACCT_STAT_NSTATS here to read
+	 * the sum of usages.
+	 */
+	if (WARN_ON_ONCE(index > CPUACCT_STAT_NSTATS))
+		return 0;
+
+#ifndef CONFIG_64BIT
+	/*
+	 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
+	 */
+	raw_spin_rq_lock_irq(cpu_rq(cpu));
+#endif
+
+	switch (index) {
+	case CPUACCT_STAT_USER:
+		data = cpustat[CPUTIME_USER] + cpustat[CPUTIME_NICE];
+		break;
+	case CPUACCT_STAT_SYSTEM:
+		data = cpustat[CPUTIME_SYSTEM] + cpustat[CPUTIME_IRQ] +
+			cpustat[CPUTIME_SOFTIRQ];
+		break;
+	case CPUACCT_STAT_NSTATS:
+		data = *cpuusage;
+		break;
+	}
+
+#ifndef CONFIG_64BIT
+	raw_spin_rq_unlock_irq(cpu_rq(cpu));
+#endif
+
+	return data;
+}
+
+static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu)
+{
+	u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
+	u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat;
+
+	/* Don't allow to reset global kernel_cpustat */
+	if (ca == &root_cpuacct)
+		return;
+
+#ifndef CONFIG_64BIT
+	/*
+	 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
+	 */
+	raw_spin_rq_lock_irq(cpu_rq(cpu));
+#endif
+	*cpuusage = 0;
+	cpustat[CPUTIME_USER] = cpustat[CPUTIME_NICE] = 0;
+	cpustat[CPUTIME_SYSTEM] = cpustat[CPUTIME_IRQ] = 0;
+	cpustat[CPUTIME_SOFTIRQ] = 0;
+
+#ifndef CONFIG_64BIT
+	raw_spin_rq_unlock_irq(cpu_rq(cpu));
+#endif
+}
+
+/* Return total CPU usage (in nanoseconds) of a group */
+static u64 __cpuusage_read(struct cgroup_subsys_state *css,
+			   enum cpuacct_stat_index index)
+{
+	struct cpuacct *ca = css_ca(css);
+	u64 totalcpuusage = 0;
+	int i;
+
+	for_each_possible_cpu(i)
+		totalcpuusage += cpuacct_cpuusage_read(ca, i, index);
+
+	return totalcpuusage;
+}
+
+static u64 cpuusage_user_read(struct cgroup_subsys_state *css,
+			      struct cftype *cft)
+{
+	return __cpuusage_read(css, CPUACCT_STAT_USER);
+}
+
+static u64 cpuusage_sys_read(struct cgroup_subsys_state *css,
+			     struct cftype *cft)
+{
+	return __cpuusage_read(css, CPUACCT_STAT_SYSTEM);
+}
+
+static u64 cpuusage_read(struct cgroup_subsys_state *css, struct cftype *cft)
+{
+	return __cpuusage_read(css, CPUACCT_STAT_NSTATS);
+}
+
+static int cpuusage_write(struct cgroup_subsys_state *css, struct cftype *cft,
+			  u64 val)
+{
+	struct cpuacct *ca = css_ca(css);
+	int cpu;
+
+	/*
+	 * Only allow '0' here to do a reset.
+	 */
+	if (val)
+		return -EINVAL;
+
+	for_each_possible_cpu(cpu)
+		cpuacct_cpuusage_write(ca, cpu);
+
+	return 0;
+}
+
+static int __cpuacct_percpu_seq_show(struct seq_file *m,
+				     enum cpuacct_stat_index index)
+{
+	struct cpuacct *ca = css_ca(seq_css(m));
+	u64 percpu;
+	int i;
+
+	for_each_possible_cpu(i) {
+		percpu = cpuacct_cpuusage_read(ca, i, index);
+		seq_printf(m, "%llu ", (unsigned long long) percpu);
+	}
+	seq_printf(m, "\n");
+	return 0;
+}
+
+static int cpuacct_percpu_user_seq_show(struct seq_file *m, void *V)
+{
+	return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_USER);
+}
+
+static int cpuacct_percpu_sys_seq_show(struct seq_file *m, void *V)
+{
+	return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_SYSTEM);
+}
+
+static int cpuacct_percpu_seq_show(struct seq_file *m, void *V)
+{
+	return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_NSTATS);
+}
+
+static int cpuacct_all_seq_show(struct seq_file *m, void *V)
+{
+	struct cpuacct *ca = css_ca(seq_css(m));
+	int index;
+	int cpu;
+
+	seq_puts(m, "cpu");
+	for (index = 0; index < CPUACCT_STAT_NSTATS; index++)
+		seq_printf(m, " %s", cpuacct_stat_desc[index]);
+	seq_puts(m, "\n");
+
+	for_each_possible_cpu(cpu) {
+		seq_printf(m, "%d", cpu);
+		for (index = 0; index < CPUACCT_STAT_NSTATS; index++)
+			seq_printf(m, " %llu",
+				   cpuacct_cpuusage_read(ca, cpu, index));
+		seq_puts(m, "\n");
+	}
+	return 0;
+}
+
+static int cpuacct_stats_show(struct seq_file *sf, void *v)
+{
+	struct cpuacct *ca = css_ca(seq_css(sf));
+	struct task_cputime cputime;
+	u64 val[CPUACCT_STAT_NSTATS];
+	int cpu;
+	int stat;
+
+	memset(&cputime, 0, sizeof(cputime));
+	for_each_possible_cpu(cpu) {
+		u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat;
+
+		cputime.utime += cpustat[CPUTIME_USER];
+		cputime.utime += cpustat[CPUTIME_NICE];
+		cputime.stime += cpustat[CPUTIME_SYSTEM];
+		cputime.stime += cpustat[CPUTIME_IRQ];
+		cputime.stime += cpustat[CPUTIME_SOFTIRQ];
+
+		cputime.sum_exec_runtime += *per_cpu_ptr(ca->cpuusage, cpu);
+	}
+
+	cputime_adjust(&cputime, &seq_css(sf)->cgroup->prev_cputime,
+		&val[CPUACCT_STAT_USER], &val[CPUACCT_STAT_SYSTEM]);
+
+	for (stat = 0; stat < CPUACCT_STAT_NSTATS; stat++) {
+		seq_printf(sf, "%s %llu\n", cpuacct_stat_desc[stat],
+			nsec_to_clock_t(val[stat]));
+	}
+
+	return 0;
+}
+
+static struct cftype files[] = {
+	{
+		.name = "usage",
+		.read_u64 = cpuusage_read,
+		.write_u64 = cpuusage_write,
+	},
+	{
+		.name = "usage_user",
+		.read_u64 = cpuusage_user_read,
+	},
+	{
+		.name = "usage_sys",
+		.read_u64 = cpuusage_sys_read,
+	},
+	{
+		.name = "usage_percpu",
+		.seq_show = cpuacct_percpu_seq_show,
+	},
+	{
+		.name = "usage_percpu_user",
+		.seq_show = cpuacct_percpu_user_seq_show,
+	},
+	{
+		.name = "usage_percpu_sys",
+		.seq_show = cpuacct_percpu_sys_seq_show,
+	},
+	{
+		.name = "usage_all",
+		.seq_show = cpuacct_all_seq_show,
+	},
+	{
+		.name = "stat",
+		.seq_show = cpuacct_stats_show,
+	},
+	{ }	/* terminate */
+};
+
+/*
+ * charge this task's execution time to its accounting group.
+ *
+ * called with rq->lock held.
+ */
+void cpuacct_charge(struct task_struct *tsk, u64 cputime)
+{
+	unsigned int cpu = task_cpu(tsk);
+	struct cpuacct *ca;
+
+	lockdep_assert_rq_held(cpu_rq(cpu));
+
+	for (ca = task_ca(tsk); ca; ca = parent_ca(ca))
+		*per_cpu_ptr(ca->cpuusage, cpu) += cputime;
+}
+
+/*
+ * Add user/system time to cpuacct.
+ *
+ * Note: it's the caller that updates the account of the root cgroup.
+ */
+void cpuacct_account_field(struct task_struct *tsk, int index, u64 val)
+{
+	struct cpuacct *ca;
+
+	for (ca = task_ca(tsk); ca != &root_cpuacct; ca = parent_ca(ca))
+		__this_cpu_add(ca->cpustat->cpustat[index], val);
+}
+
+struct cgroup_subsys cpuacct_cgrp_subsys = {
+	.css_alloc	= cpuacct_css_alloc,
+	.css_free	= cpuacct_css_free,
+	.legacy_cftypes	= files,
+	.early_init	= true,
+};
diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
new file mode 100644
index 0000000000..57c92d751b
--- /dev/null
+++ b/kernel/sched/cpudeadline.c
@@ -0,0 +1,295 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  kernel/sched/cpudeadline.c
+ *
+ *  Global CPU deadline management
+ *
+ *  Author: Juri Lelli <j.lelli@sssup.it>
+ */
+
+static inline int parent(int i)
+{
+	return (i - 1) >> 1;
+}
+
+static inline int left_child(int i)
+{
+	return (i << 1) + 1;
+}
+
+static inline int right_child(int i)
+{
+	return (i << 1) + 2;
+}
+
+static void cpudl_heapify_down(struct cpudl *cp, int idx)
+{
+	int l, r, largest;
+
+	int orig_cpu = cp->elements[idx].cpu;
+	u64 orig_dl = cp->elements[idx].dl;
+
+	if (left_child(idx) >= cp->size)
+		return;
+
+	/* adapted from lib/prio_heap.c */
+	while (1) {
+		u64 largest_dl;
+
+		l = left_child(idx);
+		r = right_child(idx);
+		largest = idx;
+		largest_dl = orig_dl;
+
+		if ((l < cp->size) && dl_time_before(orig_dl,
+						cp->elements[l].dl)) {
+			largest = l;
+			largest_dl = cp->elements[l].dl;
+		}
+		if ((r < cp->size) && dl_time_before(largest_dl,
+						cp->elements[r].dl))
+			largest = r;
+
+		if (largest == idx)
+			break;
+
+		/* pull largest child onto idx */
+		cp->elements[idx].cpu = cp->elements[largest].cpu;
+		cp->elements[idx].dl = cp->elements[largest].dl;
+		cp->elements[cp->elements[idx].cpu].idx = idx;
+		idx = largest;
+	}
+	/* actual push down of saved original values orig_* */
+	cp->elements[idx].cpu = orig_cpu;
+	cp->elements[idx].dl = orig_dl;
+	cp->elements[cp->elements[idx].cpu].idx = idx;
+}
+
+static void cpudl_heapify_up(struct cpudl *cp, int idx)
+{
+	int p;
+
+	int orig_cpu = cp->elements[idx].cpu;
+	u64 orig_dl = cp->elements[idx].dl;
+
+	if (idx == 0)
+		return;
+
+	do {
+		p = parent(idx);
+		if (dl_time_before(orig_dl, cp->elements[p].dl))
+			break;
+		/* pull parent onto idx */
+		cp->elements[idx].cpu = cp->elements[p].cpu;
+		cp->elements[idx].dl = cp->elements[p].dl;
+		cp->elements[cp->elements[idx].cpu].idx = idx;
+		idx = p;
+	} while (idx != 0);
+	/* actual push up of saved original values orig_* */
+	cp->elements[idx].cpu = orig_cpu;
+	cp->elements[idx].dl = orig_dl;
+	cp->elements[cp->elements[idx].cpu].idx = idx;
+}
+
+static void cpudl_heapify(struct cpudl *cp, int idx)
+{
+	if (idx > 0 && dl_time_before(cp->elements[parent(idx)].dl,
+				cp->elements[idx].dl))
+		cpudl_heapify_up(cp, idx);
+	else
+		cpudl_heapify_down(cp, idx);
+}
+
+static inline int cpudl_maximum(struct cpudl *cp)
+{
+	return cp->elements[0].cpu;
+}
+
+/*
+ * cpudl_find - find the best (later-dl) CPU in the system
+ * @cp: the cpudl max-heap context
+ * @p: the task
+ * @later_mask: a mask to fill in with the selected CPUs (or NULL)
+ *
+ * Returns: int - CPUs were found
+ */
+int cpudl_find(struct cpudl *cp, struct task_struct *p,
+	       struct cpumask *later_mask)
+{
+	const struct sched_dl_entity *dl_se = &p->dl;
+
+	if (later_mask &&
+	    cpumask_and(later_mask, cp->free_cpus, &p->cpus_mask)) {
+		unsigned long cap, max_cap = 0;
+		int cpu, max_cpu = -1;
+
+		if (!sched_asym_cpucap_active())
+			return 1;
+
+		/* Ensure the capacity of the CPUs fits the task. */
+		for_each_cpu(cpu, later_mask) {
+			if (!dl_task_fits_capacity(p, cpu)) {
+				cpumask_clear_cpu(cpu, later_mask);
+
+				cap = capacity_orig_of(cpu);
+
+				if (cap > max_cap ||
+				    (cpu == task_cpu(p) && cap == max_cap)) {
+					max_cap = cap;
+					max_cpu = cpu;
+				}
+			}
+		}
+
+		if (cpumask_empty(later_mask))
+			cpumask_set_cpu(max_cpu, later_mask);
+
+		return 1;
+	} else {
+		int best_cpu = cpudl_maximum(cp);
+
+		WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
+
+		if (cpumask_test_cpu(best_cpu, &p->cpus_mask) &&
+		    dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
+			if (later_mask)
+				cpumask_set_cpu(best_cpu, later_mask);
+
+			return 1;
+		}
+	}
+	return 0;
+}
+
+/*
+ * cpudl_clear - remove a CPU from the cpudl max-heap
+ * @cp: the cpudl max-heap context
+ * @cpu: the target CPU
+ *
+ * Notes: assumes cpu_rq(cpu)->lock is locked
+ *
+ * Returns: (void)
+ */
+void cpudl_clear(struct cpudl *cp, int cpu)
+{
+	int old_idx, new_cpu;
+	unsigned long flags;
+
+	WARN_ON(!cpu_present(cpu));
+
+	raw_spin_lock_irqsave(&cp->lock, flags);
+
+	old_idx = cp->elements[cpu].idx;
+	if (old_idx == IDX_INVALID) {
+		/*
+		 * Nothing to remove if old_idx was invalid.
+		 * This could happen if a rq_offline_dl is
+		 * called for a CPU without -dl tasks running.
+		 */
+	} else {
+		new_cpu = cp->elements[cp->size - 1].cpu;
+		cp->elements[old_idx].dl = cp->elements[cp->size - 1].dl;
+		cp->elements[old_idx].cpu = new_cpu;
+		cp->size--;
+		cp->elements[new_cpu].idx = old_idx;
+		cp->elements[cpu].idx = IDX_INVALID;
+		cpudl_heapify(cp, old_idx);
+
+		cpumask_set_cpu(cpu, cp->free_cpus);
+	}
+	raw_spin_unlock_irqrestore(&cp->lock, flags);
+}
+
+/*
+ * cpudl_set - update the cpudl max-heap
+ * @cp: the cpudl max-heap context
+ * @cpu: the target CPU
+ * @dl: the new earliest deadline for this CPU
+ *
+ * Notes: assumes cpu_rq(cpu)->lock is locked
+ *
+ * Returns: (void)
+ */
+void cpudl_set(struct cpudl *cp, int cpu, u64 dl)
+{
+	int old_idx;
+	unsigned long flags;
+
+	WARN_ON(!cpu_present(cpu));
+
+	raw_spin_lock_irqsave(&cp->lock, flags);
+
+	old_idx = cp->elements[cpu].idx;
+	if (old_idx == IDX_INVALID) {
+		int new_idx = cp->size++;
+
+		cp->elements[new_idx].dl = dl;
+		cp->elements[new_idx].cpu = cpu;
+		cp->elements[cpu].idx = new_idx;
+		cpudl_heapify_up(cp, new_idx);
+		cpumask_clear_cpu(cpu, cp->free_cpus);
+	} else {
+		cp->elements[old_idx].dl = dl;
+		cpudl_heapify(cp, old_idx);
+	}
+
+	raw_spin_unlock_irqrestore(&cp->lock, flags);
+}
+
+/*
+ * cpudl_set_freecpu - Set the cpudl.free_cpus
+ * @cp: the cpudl max-heap context
+ * @cpu: rd attached CPU
+ */
+void cpudl_set_freecpu(struct cpudl *cp, int cpu)
+{
+	cpumask_set_cpu(cpu, cp->free_cpus);
+}
+
+/*
+ * cpudl_clear_freecpu - Clear the cpudl.free_cpus
+ * @cp: the cpudl max-heap context
+ * @cpu: rd attached CPU
+ */
+void cpudl_clear_freecpu(struct cpudl *cp, int cpu)
+{
+	cpumask_clear_cpu(cpu, cp->free_cpus);
+}
+
+/*
+ * cpudl_init - initialize the cpudl structure
+ * @cp: the cpudl max-heap context
+ */
+int cpudl_init(struct cpudl *cp)
+{
+	int i;
+
+	raw_spin_lock_init(&cp->lock);
+	cp->size = 0;
+
+	cp->elements = kcalloc(nr_cpu_ids,
+			       sizeof(struct cpudl_item),
+			       GFP_KERNEL);
+	if (!cp->elements)
+		return -ENOMEM;
+
+	if (!zalloc_cpumask_var(&cp->free_cpus, GFP_KERNEL)) {
+		kfree(cp->elements);
+		return -ENOMEM;
+	}
+
+	for_each_possible_cpu(i)
+		cp->elements[i].idx = IDX_INVALID;
+
+	return 0;
+}
+
+/*
+ * cpudl_cleanup - clean up the cpudl structure
+ * @cp: the cpudl max-heap context
+ */
+void cpudl_cleanup(struct cpudl *cp)
+{
+	free_cpumask_var(cp->free_cpus);
+	kfree(cp->elements);
+}
diff --git a/kernel/sched/cpudeadline.h b/kernel/sched/cpudeadline.h
new file mode 100644
index 0000000000..0adeda93b5
--- /dev/null
+++ b/kernel/sched/cpudeadline.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#define IDX_INVALID		-1
+
+struct cpudl_item {
+	u64			dl;
+	int			cpu;
+	int			idx;
+};
+
+struct cpudl {
+	raw_spinlock_t		lock;
+	int			size;
+	cpumask_var_t		free_cpus;
+	struct cpudl_item	*elements;
+};
+
+#ifdef CONFIG_SMP
+int  cpudl_find(struct cpudl *cp, struct task_struct *p, struct cpumask *later_mask);
+void cpudl_set(struct cpudl *cp, int cpu, u64 dl);
+void cpudl_clear(struct cpudl *cp, int cpu);
+int  cpudl_init(struct cpudl *cp);
+void cpudl_set_freecpu(struct cpudl *cp, int cpu);
+void cpudl_clear_freecpu(struct cpudl *cp, int cpu);
+void cpudl_cleanup(struct cpudl *cp);
+#endif /* CONFIG_SMP */
diff --git a/kernel/sched/cpufreq.c b/kernel/sched/cpufreq.c
new file mode 100644
index 0000000000..5252fb191f
--- /dev/null
+++ b/kernel/sched/cpufreq.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Scheduler code and data structures related to cpufreq.
+ *
+ * Copyright (C) 2016, Intel Corporation
+ * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+ */
+
+DEFINE_PER_CPU(struct update_util_data __rcu *, cpufreq_update_util_data);
+
+/**
+ * cpufreq_add_update_util_hook - Populate the CPU's update_util_data pointer.
+ * @cpu: The CPU to set the pointer for.
+ * @data: New pointer value.
+ * @func: Callback function to set for the CPU.
+ *
+ * Set and publish the update_util_data pointer for the given CPU.
+ *
+ * The update_util_data pointer of @cpu is set to @data and the callback
+ * function pointer in the target struct update_util_data is set to @func.
+ * That function will be called by cpufreq_update_util() from RCU-sched
+ * read-side critical sections, so it must not sleep.  @data will always be
+ * passed to it as the first argument which allows the function to get to the
+ * target update_util_data structure and its container.
+ *
+ * The update_util_data pointer of @cpu must be NULL when this function is
+ * called or it will WARN() and return with no effect.
+ */
+void cpufreq_add_update_util_hook(int cpu, struct update_util_data *data,
+			void (*func)(struct update_util_data *data, u64 time,
+				     unsigned int flags))
+{
+	if (WARN_ON(!data || !func))
+		return;
+
+	if (WARN_ON(per_cpu(cpufreq_update_util_data, cpu)))
+		return;
+
+	data->func = func;
+	rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), data);
+}
+EXPORT_SYMBOL_GPL(cpufreq_add_update_util_hook);
+
+/**
+ * cpufreq_remove_update_util_hook - Clear the CPU's update_util_data pointer.
+ * @cpu: The CPU to clear the pointer for.
+ *
+ * Clear the update_util_data pointer for the given CPU.
+ *
+ * Callers must use RCU callbacks to free any memory that might be
+ * accessed via the old update_util_data pointer or invoke synchronize_rcu()
+ * right after this function to avoid use-after-free.
+ */
+void cpufreq_remove_update_util_hook(int cpu)
+{
+	rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), NULL);
+}
+EXPORT_SYMBOL_GPL(cpufreq_remove_update_util_hook);
+
+/**
+ * cpufreq_this_cpu_can_update - Check if cpufreq policy can be updated.
+ * @policy: cpufreq policy to check.
+ *
+ * Return 'true' if:
+ * - the local and remote CPUs share @policy,
+ * - dvfs_possible_from_any_cpu is set in @policy and the local CPU is not going
+ *   offline (in which case it is not expected to run cpufreq updates any more).
+ */
+bool cpufreq_this_cpu_can_update(struct cpufreq_policy *policy)
+{
+	return cpumask_test_cpu(smp_processor_id(), policy->cpus) ||
+		(policy->dvfs_possible_from_any_cpu &&
+		 rcu_dereference_sched(*this_cpu_ptr(&cpufreq_update_util_data)));
+}
diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
new file mode 100644
index 0000000000..458d359f59
--- /dev/null
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -0,0 +1,867 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * CPUFreq governor based on scheduler-provided CPU utilization data.
+ *
+ * Copyright (C) 2016, Intel Corporation
+ * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+ */
+
+#define IOWAIT_BOOST_MIN	(SCHED_CAPACITY_SCALE / 8)
+
+struct sugov_tunables {
+	struct gov_attr_set	attr_set;
+	unsigned int		rate_limit_us;
+};
+
+struct sugov_policy {
+	struct cpufreq_policy	*policy;
+
+	struct sugov_tunables	*tunables;
+	struct list_head	tunables_hook;
+
+	raw_spinlock_t		update_lock;
+	u64			last_freq_update_time;
+	s64			freq_update_delay_ns;
+	unsigned int		next_freq;
+	unsigned int		cached_raw_freq;
+
+	/* The next fields are only needed if fast switch cannot be used: */
+	struct			irq_work irq_work;
+	struct			kthread_work work;
+	struct			mutex work_lock;
+	struct			kthread_worker worker;
+	struct task_struct	*thread;
+	bool			work_in_progress;
+
+	bool			limits_changed;
+	bool			need_freq_update;
+};
+
+struct sugov_cpu {
+	struct update_util_data	update_util;
+	struct sugov_policy	*sg_policy;
+	unsigned int		cpu;
+
+	bool			iowait_boost_pending;
+	unsigned int		iowait_boost;
+	u64			last_update;
+
+	unsigned long		util;
+	unsigned long		bw_dl;
+
+	/* The field below is for single-CPU policies only: */
+#ifdef CONFIG_NO_HZ_COMMON
+	unsigned long		saved_idle_calls;
+#endif
+};
+
+static DEFINE_PER_CPU(struct sugov_cpu, sugov_cpu);
+
+/************************ Governor internals ***********************/
+
+static bool sugov_should_update_freq(struct sugov_policy *sg_policy, u64 time)
+{
+	s64 delta_ns;
+
+	/*
+	 * Since cpufreq_update_util() is called with rq->lock held for
+	 * the @target_cpu, our per-CPU data is fully serialized.
+	 *
+	 * However, drivers cannot in general deal with cross-CPU
+	 * requests, so while get_next_freq() will work, our
+	 * sugov_update_commit() call may not for the fast switching platforms.
+	 *
+	 * Hence stop here for remote requests if they aren't supported
+	 * by the hardware, as calculating the frequency is pointless if
+	 * we cannot in fact act on it.
+	 *
+	 * This is needed on the slow switching platforms too to prevent CPUs
+	 * going offline from leaving stale IRQ work items behind.
+	 */
+	if (!cpufreq_this_cpu_can_update(sg_policy->policy))
+		return false;
+
+	if (unlikely(sg_policy->limits_changed)) {
+		sg_policy->limits_changed = false;
+		sg_policy->need_freq_update = true;
+		return true;
+	}
+
+	delta_ns = time - sg_policy->last_freq_update_time;
+
+	return delta_ns >= sg_policy->freq_update_delay_ns;
+}
+
+static bool sugov_update_next_freq(struct sugov_policy *sg_policy, u64 time,
+				   unsigned int next_freq)
+{
+	if (sg_policy->need_freq_update)
+		sg_policy->need_freq_update = cpufreq_driver_test_flags(CPUFREQ_NEED_UPDATE_LIMITS);
+	else if (sg_policy->next_freq == next_freq)
+		return false;
+
+	sg_policy->next_freq = next_freq;
+	sg_policy->last_freq_update_time = time;
+
+	return true;
+}
+
+static void sugov_deferred_update(struct sugov_policy *sg_policy)
+{
+	if (!sg_policy->work_in_progress) {
+		sg_policy->work_in_progress = true;
+		irq_work_queue(&sg_policy->irq_work);
+	}
+}
+
+/**
+ * get_next_freq - Compute a new frequency for a given cpufreq policy.
+ * @sg_policy: schedutil policy object to compute the new frequency for.
+ * @util: Current CPU utilization.
+ * @max: CPU capacity.
+ *
+ * If the utilization is frequency-invariant, choose the new frequency to be
+ * proportional to it, that is
+ *
+ * next_freq = C * max_freq * util / max
+ *
+ * Otherwise, approximate the would-be frequency-invariant utilization by
+ * util_raw * (curr_freq / max_freq) which leads to
+ *
+ * next_freq = C * curr_freq * util_raw / max
+ *
+ * Take C = 1.25 for the frequency tipping point at (util / max) = 0.8.
+ *
+ * The lowest driver-supported frequency which is equal or greater than the raw
+ * next_freq (as calculated above) is returned, subject to policy min/max and
+ * cpufreq driver limitations.
+ */
+static unsigned int get_next_freq(struct sugov_policy *sg_policy,
+				  unsigned long util, unsigned long max)
+{
+	struct cpufreq_policy *policy = sg_policy->policy;
+	unsigned int freq = arch_scale_freq_invariant() ?
+				policy->cpuinfo.max_freq : policy->cur;
+
+	util = map_util_perf(util);
+	freq = map_util_freq(util, freq, max);
+
+	if (freq == sg_policy->cached_raw_freq && !sg_policy->need_freq_update)
+		return sg_policy->next_freq;
+
+	sg_policy->cached_raw_freq = freq;
+	return cpufreq_driver_resolve_freq(policy, freq);
+}
+
+static void sugov_get_util(struct sugov_cpu *sg_cpu)
+{
+	unsigned long util = cpu_util_cfs_boost(sg_cpu->cpu);
+	struct rq *rq = cpu_rq(sg_cpu->cpu);
+
+	sg_cpu->bw_dl = cpu_bw_dl(rq);
+	sg_cpu->util = effective_cpu_util(sg_cpu->cpu, util,
+					  FREQUENCY_UTIL, NULL);
+}
+
+/**
+ * sugov_iowait_reset() - Reset the IO boost status of a CPU.
+ * @sg_cpu: the sugov data for the CPU to boost
+ * @time: the update time from the caller
+ * @set_iowait_boost: true if an IO boost has been requested
+ *
+ * The IO wait boost of a task is disabled after a tick since the last update
+ * of a CPU. If a new IO wait boost is requested after more then a tick, then
+ * we enable the boost starting from IOWAIT_BOOST_MIN, which improves energy
+ * efficiency by ignoring sporadic wakeups from IO.
+ */
+static bool sugov_iowait_reset(struct sugov_cpu *sg_cpu, u64 time,
+			       bool set_iowait_boost)
+{
+	s64 delta_ns = time - sg_cpu->last_update;
+
+	/* Reset boost only if a tick has elapsed since last request */
+	if (delta_ns <= TICK_NSEC)
+		return false;
+
+	sg_cpu->iowait_boost = set_iowait_boost ? IOWAIT_BOOST_MIN : 0;
+	sg_cpu->iowait_boost_pending = set_iowait_boost;
+
+	return true;
+}
+
+/**
+ * sugov_iowait_boost() - Updates the IO boost status of a CPU.
+ * @sg_cpu: the sugov data for the CPU to boost
+ * @time: the update time from the caller
+ * @flags: SCHED_CPUFREQ_IOWAIT if the task is waking up after an IO wait
+ *
+ * Each time a task wakes up after an IO operation, the CPU utilization can be
+ * boosted to a certain utilization which doubles at each "frequent and
+ * successive" wakeup from IO, ranging from IOWAIT_BOOST_MIN to the utilization
+ * of the maximum OPP.
+ *
+ * To keep doubling, an IO boost has to be requested at least once per tick,
+ * otherwise we restart from the utilization of the minimum OPP.
+ */
+static void sugov_iowait_boost(struct sugov_cpu *sg_cpu, u64 time,
+			       unsigned int flags)
+{
+	bool set_iowait_boost = flags & SCHED_CPUFREQ_IOWAIT;
+
+	/* Reset boost if the CPU appears to have been idle enough */
+	if (sg_cpu->iowait_boost &&
+	    sugov_iowait_reset(sg_cpu, time, set_iowait_boost))
+		return;
+
+	/* Boost only tasks waking up after IO */
+	if (!set_iowait_boost)
+		return;
+
+	/* Ensure boost doubles only one time at each request */
+	if (sg_cpu->iowait_boost_pending)
+		return;
+	sg_cpu->iowait_boost_pending = true;
+
+	/* Double the boost at each request */
+	if (sg_cpu->iowait_boost) {
+		sg_cpu->iowait_boost =
+			min_t(unsigned int, sg_cpu->iowait_boost << 1, SCHED_CAPACITY_SCALE);
+		return;
+	}
+
+	/* First wakeup after IO: start with minimum boost */
+	sg_cpu->iowait_boost = IOWAIT_BOOST_MIN;
+}
+
+/**
+ * sugov_iowait_apply() - Apply the IO boost to a CPU.
+ * @sg_cpu: the sugov data for the cpu to boost
+ * @time: the update time from the caller
+ * @max_cap: the max CPU capacity
+ *
+ * A CPU running a task which woken up after an IO operation can have its
+ * utilization boosted to speed up the completion of those IO operations.
+ * The IO boost value is increased each time a task wakes up from IO, in
+ * sugov_iowait_apply(), and it's instead decreased by this function,
+ * each time an increase has not been requested (!iowait_boost_pending).
+ *
+ * A CPU which also appears to have been idle for at least one tick has also
+ * its IO boost utilization reset.
+ *
+ * This mechanism is designed to boost high frequently IO waiting tasks, while
+ * being more conservative on tasks which does sporadic IO operations.
+ */
+static void sugov_iowait_apply(struct sugov_cpu *sg_cpu, u64 time,
+			       unsigned long max_cap)
+{
+	unsigned long boost;
+
+	/* No boost currently required */
+	if (!sg_cpu->iowait_boost)
+		return;
+
+	/* Reset boost if the CPU appears to have been idle enough */
+	if (sugov_iowait_reset(sg_cpu, time, false))
+		return;
+
+	if (!sg_cpu->iowait_boost_pending) {
+		/*
+		 * No boost pending; reduce the boost value.
+		 */
+		sg_cpu->iowait_boost >>= 1;
+		if (sg_cpu->iowait_boost < IOWAIT_BOOST_MIN) {
+			sg_cpu->iowait_boost = 0;
+			return;
+		}
+	}
+
+	sg_cpu->iowait_boost_pending = false;
+
+	/*
+	 * sg_cpu->util is already in capacity scale; convert iowait_boost
+	 * into the same scale so we can compare.
+	 */
+	boost = (sg_cpu->iowait_boost * max_cap) >> SCHED_CAPACITY_SHIFT;
+	boost = uclamp_rq_util_with(cpu_rq(sg_cpu->cpu), boost, NULL);
+	if (sg_cpu->util < boost)
+		sg_cpu->util = boost;
+}
+
+#ifdef CONFIG_NO_HZ_COMMON
+static bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu)
+{
+	unsigned long idle_calls = tick_nohz_get_idle_calls_cpu(sg_cpu->cpu);
+	bool ret = idle_calls == sg_cpu->saved_idle_calls;
+
+	sg_cpu->saved_idle_calls = idle_calls;
+	return ret;
+}
+#else
+static inline bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu) { return false; }
+#endif /* CONFIG_NO_HZ_COMMON */
+
+/*
+ * Make sugov_should_update_freq() ignore the rate limit when DL
+ * has increased the utilization.
+ */
+static inline void ignore_dl_rate_limit(struct sugov_cpu *sg_cpu)
+{
+	if (cpu_bw_dl(cpu_rq(sg_cpu->cpu)) > sg_cpu->bw_dl)
+		sg_cpu->sg_policy->limits_changed = true;
+}
+
+static inline bool sugov_update_single_common(struct sugov_cpu *sg_cpu,
+					      u64 time, unsigned long max_cap,
+					      unsigned int flags)
+{
+	sugov_iowait_boost(sg_cpu, time, flags);
+	sg_cpu->last_update = time;
+
+	ignore_dl_rate_limit(sg_cpu);
+
+	if (!sugov_should_update_freq(sg_cpu->sg_policy, time))
+		return false;
+
+	sugov_get_util(sg_cpu);
+	sugov_iowait_apply(sg_cpu, time, max_cap);
+
+	return true;
+}
+
+static void sugov_update_single_freq(struct update_util_data *hook, u64 time,
+				     unsigned int flags)
+{
+	struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
+	struct sugov_policy *sg_policy = sg_cpu->sg_policy;
+	unsigned int cached_freq = sg_policy->cached_raw_freq;
+	unsigned long max_cap;
+	unsigned int next_f;
+
+	max_cap = arch_scale_cpu_capacity(sg_cpu->cpu);
+
+	if (!sugov_update_single_common(sg_cpu, time, max_cap, flags))
+		return;
+
+	next_f = get_next_freq(sg_policy, sg_cpu->util, max_cap);
+	/*
+	 * Do not reduce the frequency if the CPU has not been idle
+	 * recently, as the reduction is likely to be premature then.
+	 *
+	 * Except when the rq is capped by uclamp_max.
+	 */
+	if (!uclamp_rq_is_capped(cpu_rq(sg_cpu->cpu)) &&
+	    sugov_cpu_is_busy(sg_cpu) && next_f < sg_policy->next_freq &&
+	    !sg_policy->need_freq_update) {
+		next_f = sg_policy->next_freq;
+
+		/* Restore cached freq as next_freq has changed */
+		sg_policy->cached_raw_freq = cached_freq;
+	}
+
+	if (!sugov_update_next_freq(sg_policy, time, next_f))
+		return;
+
+	/*
+	 * This code runs under rq->lock for the target CPU, so it won't run
+	 * concurrently on two different CPUs for the same target and it is not
+	 * necessary to acquire the lock in the fast switch case.
+	 */
+	if (sg_policy->policy->fast_switch_enabled) {
+		cpufreq_driver_fast_switch(sg_policy->policy, next_f);
+	} else {
+		raw_spin_lock(&sg_policy->update_lock);
+		sugov_deferred_update(sg_policy);
+		raw_spin_unlock(&sg_policy->update_lock);
+	}
+}
+
+static void sugov_update_single_perf(struct update_util_data *hook, u64 time,
+				     unsigned int flags)
+{
+	struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
+	unsigned long prev_util = sg_cpu->util;
+	unsigned long max_cap;
+
+	/*
+	 * Fall back to the "frequency" path if frequency invariance is not
+	 * supported, because the direct mapping between the utilization and
+	 * the performance levels depends on the frequency invariance.
+	 */
+	if (!arch_scale_freq_invariant()) {
+		sugov_update_single_freq(hook, time, flags);
+		return;
+	}
+
+	max_cap = arch_scale_cpu_capacity(sg_cpu->cpu);
+
+	if (!sugov_update_single_common(sg_cpu, time, max_cap, flags))
+		return;
+
+	/*
+	 * Do not reduce the target performance level if the CPU has not been
+	 * idle recently, as the reduction is likely to be premature then.
+	 *
+	 * Except when the rq is capped by uclamp_max.
+	 */
+	if (!uclamp_rq_is_capped(cpu_rq(sg_cpu->cpu)) &&
+	    sugov_cpu_is_busy(sg_cpu) && sg_cpu->util < prev_util)
+		sg_cpu->util = prev_util;
+
+	cpufreq_driver_adjust_perf(sg_cpu->cpu, map_util_perf(sg_cpu->bw_dl),
+				   map_util_perf(sg_cpu->util), max_cap);
+
+	sg_cpu->sg_policy->last_freq_update_time = time;
+}
+
+static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time)
+{
+	struct sugov_policy *sg_policy = sg_cpu->sg_policy;
+	struct cpufreq_policy *policy = sg_policy->policy;
+	unsigned long util = 0, max_cap;
+	unsigned int j;
+
+	max_cap = arch_scale_cpu_capacity(sg_cpu->cpu);
+
+	for_each_cpu(j, policy->cpus) {
+		struct sugov_cpu *j_sg_cpu = &per_cpu(sugov_cpu, j);
+
+		sugov_get_util(j_sg_cpu);
+		sugov_iowait_apply(j_sg_cpu, time, max_cap);
+
+		util = max(j_sg_cpu->util, util);
+	}
+
+	return get_next_freq(sg_policy, util, max_cap);
+}
+
+static void
+sugov_update_shared(struct update_util_data *hook, u64 time, unsigned int flags)
+{
+	struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
+	struct sugov_policy *sg_policy = sg_cpu->sg_policy;
+	unsigned int next_f;
+
+	raw_spin_lock(&sg_policy->update_lock);
+
+	sugov_iowait_boost(sg_cpu, time, flags);
+	sg_cpu->last_update = time;
+
+	ignore_dl_rate_limit(sg_cpu);
+
+	if (sugov_should_update_freq(sg_policy, time)) {
+		next_f = sugov_next_freq_shared(sg_cpu, time);
+
+		if (!sugov_update_next_freq(sg_policy, time, next_f))
+			goto unlock;
+
+		if (sg_policy->policy->fast_switch_enabled)
+			cpufreq_driver_fast_switch(sg_policy->policy, next_f);
+		else
+			sugov_deferred_update(sg_policy);
+	}
+unlock:
+	raw_spin_unlock(&sg_policy->update_lock);
+}
+
+static void sugov_work(struct kthread_work *work)
+{
+	struct sugov_policy *sg_policy = container_of(work, struct sugov_policy, work);
+	unsigned int freq;
+	unsigned long flags;
+
+	/*
+	 * Hold sg_policy->update_lock shortly to handle the case where:
+	 * in case sg_policy->next_freq is read here, and then updated by
+	 * sugov_deferred_update() just before work_in_progress is set to false
+	 * here, we may miss queueing the new update.
+	 *
+	 * Note: If a work was queued after the update_lock is released,
+	 * sugov_work() will just be called again by kthread_work code; and the
+	 * request will be proceed before the sugov thread sleeps.
+	 */
+	raw_spin_lock_irqsave(&sg_policy->update_lock, flags);
+	freq = sg_policy->next_freq;
+	sg_policy->work_in_progress = false;
+	raw_spin_unlock_irqrestore(&sg_policy->update_lock, flags);
+
+	mutex_lock(&sg_policy->work_lock);
+	__cpufreq_driver_target(sg_policy->policy, freq, CPUFREQ_RELATION_L);
+	mutex_unlock(&sg_policy->work_lock);
+}
+
+static void sugov_irq_work(struct irq_work *irq_work)
+{
+	struct sugov_policy *sg_policy;
+
+	sg_policy = container_of(irq_work, struct sugov_policy, irq_work);
+
+	kthread_queue_work(&sg_policy->worker, &sg_policy->work);
+}
+
+/************************** sysfs interface ************************/
+
+static struct sugov_tunables *global_tunables;
+static DEFINE_MUTEX(global_tunables_lock);
+
+static inline struct sugov_tunables *to_sugov_tunables(struct gov_attr_set *attr_set)
+{
+	return container_of(attr_set, struct sugov_tunables, attr_set);
+}
+
+static ssize_t rate_limit_us_show(struct gov_attr_set *attr_set, char *buf)
+{
+	struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
+
+	return sprintf(buf, "%u\n", tunables->rate_limit_us);
+}
+
+static ssize_t
+rate_limit_us_store(struct gov_attr_set *attr_set, const char *buf, size_t count)
+{
+	struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
+	struct sugov_policy *sg_policy;
+	unsigned int rate_limit_us;
+
+	if (kstrtouint(buf, 10, &rate_limit_us))
+		return -EINVAL;
+
+	tunables->rate_limit_us = rate_limit_us;
+
+	list_for_each_entry(sg_policy, &attr_set->policy_list, tunables_hook)
+		sg_policy->freq_update_delay_ns = rate_limit_us * NSEC_PER_USEC;
+
+	return count;
+}
+
+static struct governor_attr rate_limit_us = __ATTR_RW(rate_limit_us);
+
+static struct attribute *sugov_attrs[] = {
+	&rate_limit_us.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(sugov);
+
+static void sugov_tunables_free(struct kobject *kobj)
+{
+	struct gov_attr_set *attr_set = to_gov_attr_set(kobj);
+
+	kfree(to_sugov_tunables(attr_set));
+}
+
+static const struct kobj_type sugov_tunables_ktype = {
+	.default_groups = sugov_groups,
+	.sysfs_ops = &governor_sysfs_ops,
+	.release = &sugov_tunables_free,
+};
+
+/********************** cpufreq governor interface *********************/
+
+struct cpufreq_governor schedutil_gov;
+
+static struct sugov_policy *sugov_policy_alloc(struct cpufreq_policy *policy)
+{
+	struct sugov_policy *sg_policy;
+
+	sg_policy = kzalloc(sizeof(*sg_policy), GFP_KERNEL);
+	if (!sg_policy)
+		return NULL;
+
+	sg_policy->policy = policy;
+	raw_spin_lock_init(&sg_policy->update_lock);
+	return sg_policy;
+}
+
+static void sugov_policy_free(struct sugov_policy *sg_policy)
+{
+	kfree(sg_policy);
+}
+
+static int sugov_kthread_create(struct sugov_policy *sg_policy)
+{
+	struct task_struct *thread;
+	struct sched_attr attr = {
+		.size		= sizeof(struct sched_attr),
+		.sched_policy	= SCHED_DEADLINE,
+		.sched_flags	= SCHED_FLAG_SUGOV,
+		.sched_nice	= 0,
+		.sched_priority	= 0,
+		/*
+		 * Fake (unused) bandwidth; workaround to "fix"
+		 * priority inheritance.
+		 */
+		.sched_runtime	=  1000000,
+		.sched_deadline = 10000000,
+		.sched_period	= 10000000,
+	};
+	struct cpufreq_policy *policy = sg_policy->policy;
+	int ret;
+
+	/* kthread only required for slow path */
+	if (policy->fast_switch_enabled)
+		return 0;
+
+	kthread_init_work(&sg_policy->work, sugov_work);
+	kthread_init_worker(&sg_policy->worker);
+	thread = kthread_create(kthread_worker_fn, &sg_policy->worker,
+				"sugov:%d",
+				cpumask_first(policy->related_cpus));
+	if (IS_ERR(thread)) {
+		pr_err("failed to create sugov thread: %ld\n", PTR_ERR(thread));
+		return PTR_ERR(thread);
+	}
+
+	ret = sched_setattr_nocheck(thread, &attr);
+	if (ret) {
+		kthread_stop(thread);
+		pr_warn("%s: failed to set SCHED_DEADLINE\n", __func__);
+		return ret;
+	}
+
+	sg_policy->thread = thread;
+	kthread_bind_mask(thread, policy->related_cpus);
+	init_irq_work(&sg_policy->irq_work, sugov_irq_work);
+	mutex_init(&sg_policy->work_lock);
+
+	wake_up_process(thread);
+
+	return 0;
+}
+
+static void sugov_kthread_stop(struct sugov_policy *sg_policy)
+{
+	/* kthread only required for slow path */
+	if (sg_policy->policy->fast_switch_enabled)
+		return;
+
+	kthread_flush_worker(&sg_policy->worker);
+	kthread_stop(sg_policy->thread);
+	mutex_destroy(&sg_policy->work_lock);
+}
+
+static struct sugov_tunables *sugov_tunables_alloc(struct sugov_policy *sg_policy)
+{
+	struct sugov_tunables *tunables;
+
+	tunables = kzalloc(sizeof(*tunables), GFP_KERNEL);
+	if (tunables) {
+		gov_attr_set_init(&tunables->attr_set, &sg_policy->tunables_hook);
+		if (!have_governor_per_policy())
+			global_tunables = tunables;
+	}
+	return tunables;
+}
+
+static void sugov_clear_global_tunables(void)
+{
+	if (!have_governor_per_policy())
+		global_tunables = NULL;
+}
+
+static int sugov_init(struct cpufreq_policy *policy)
+{
+	struct sugov_policy *sg_policy;
+	struct sugov_tunables *tunables;
+	int ret = 0;
+
+	/* State should be equivalent to EXIT */
+	if (policy->governor_data)
+		return -EBUSY;
+
+	cpufreq_enable_fast_switch(policy);
+
+	sg_policy = sugov_policy_alloc(policy);
+	if (!sg_policy) {
+		ret = -ENOMEM;
+		goto disable_fast_switch;
+	}
+
+	ret = sugov_kthread_create(sg_policy);
+	if (ret)
+		goto free_sg_policy;
+
+	mutex_lock(&global_tunables_lock);
+
+	if (global_tunables) {
+		if (WARN_ON(have_governor_per_policy())) {
+			ret = -EINVAL;
+			goto stop_kthread;
+		}
+		policy->governor_data = sg_policy;
+		sg_policy->tunables = global_tunables;
+
+		gov_attr_set_get(&global_tunables->attr_set, &sg_policy->tunables_hook);
+		goto out;
+	}
+
+	tunables = sugov_tunables_alloc(sg_policy);
+	if (!tunables) {
+		ret = -ENOMEM;
+		goto stop_kthread;
+	}
+
+	tunables->rate_limit_us = cpufreq_policy_transition_delay_us(policy);
+
+	policy->governor_data = sg_policy;
+	sg_policy->tunables = tunables;
+
+	ret = kobject_init_and_add(&tunables->attr_set.kobj, &sugov_tunables_ktype,
+				   get_governor_parent_kobj(policy), "%s",
+				   schedutil_gov.name);
+	if (ret)
+		goto fail;
+
+out:
+	mutex_unlock(&global_tunables_lock);
+	return 0;
+
+fail:
+	kobject_put(&tunables->attr_set.kobj);
+	policy->governor_data = NULL;
+	sugov_clear_global_tunables();
+
+stop_kthread:
+	sugov_kthread_stop(sg_policy);
+	mutex_unlock(&global_tunables_lock);
+
+free_sg_policy:
+	sugov_policy_free(sg_policy);
+
+disable_fast_switch:
+	cpufreq_disable_fast_switch(policy);
+
+	pr_err("initialization failed (error %d)\n", ret);
+	return ret;
+}
+
+static void sugov_exit(struct cpufreq_policy *policy)
+{
+	struct sugov_policy *sg_policy = policy->governor_data;
+	struct sugov_tunables *tunables = sg_policy->tunables;
+	unsigned int count;
+
+	mutex_lock(&global_tunables_lock);
+
+	count = gov_attr_set_put(&tunables->attr_set, &sg_policy->tunables_hook);
+	policy->governor_data = NULL;
+	if (!count)
+		sugov_clear_global_tunables();
+
+	mutex_unlock(&global_tunables_lock);
+
+	sugov_kthread_stop(sg_policy);
+	sugov_policy_free(sg_policy);
+	cpufreq_disable_fast_switch(policy);
+}
+
+static int sugov_start(struct cpufreq_policy *policy)
+{
+	struct sugov_policy *sg_policy = policy->governor_data;
+	void (*uu)(struct update_util_data *data, u64 time, unsigned int flags);
+	unsigned int cpu;
+
+	sg_policy->freq_update_delay_ns	= sg_policy->tunables->rate_limit_us * NSEC_PER_USEC;
+	sg_policy->last_freq_update_time	= 0;
+	sg_policy->next_freq			= 0;
+	sg_policy->work_in_progress		= false;
+	sg_policy->limits_changed		= false;
+	sg_policy->cached_raw_freq		= 0;
+
+	sg_policy->need_freq_update = cpufreq_driver_test_flags(CPUFREQ_NEED_UPDATE_LIMITS);
+
+	for_each_cpu(cpu, policy->cpus) {
+		struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);
+
+		memset(sg_cpu, 0, sizeof(*sg_cpu));
+		sg_cpu->cpu			= cpu;
+		sg_cpu->sg_policy		= sg_policy;
+	}
+
+	if (policy_is_shared(policy))
+		uu = sugov_update_shared;
+	else if (policy->fast_switch_enabled && cpufreq_driver_has_adjust_perf())
+		uu = sugov_update_single_perf;
+	else
+		uu = sugov_update_single_freq;
+
+	for_each_cpu(cpu, policy->cpus) {
+		struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);
+
+		cpufreq_add_update_util_hook(cpu, &sg_cpu->update_util, uu);
+	}
+	return 0;
+}
+
+static void sugov_stop(struct cpufreq_policy *policy)
+{
+	struct sugov_policy *sg_policy = policy->governor_data;
+	unsigned int cpu;
+
+	for_each_cpu(cpu, policy->cpus)
+		cpufreq_remove_update_util_hook(cpu);
+
+	synchronize_rcu();
+
+	if (!policy->fast_switch_enabled) {
+		irq_work_sync(&sg_policy->irq_work);
+		kthread_cancel_work_sync(&sg_policy->work);
+	}
+}
+
+static void sugov_limits(struct cpufreq_policy *policy)
+{
+	struct sugov_policy *sg_policy = policy->governor_data;
+
+	if (!policy->fast_switch_enabled) {
+		mutex_lock(&sg_policy->work_lock);
+		cpufreq_policy_apply_limits(policy);
+		mutex_unlock(&sg_policy->work_lock);
+	}
+
+	sg_policy->limits_changed = true;
+}
+
+struct cpufreq_governor schedutil_gov = {
+	.name			= "schedutil",
+	.owner			= THIS_MODULE,
+	.flags			= CPUFREQ_GOV_DYNAMIC_SWITCHING,
+	.init			= sugov_init,
+	.exit			= sugov_exit,
+	.start			= sugov_start,
+	.stop			= sugov_stop,
+	.limits			= sugov_limits,
+};
+
+#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL
+struct cpufreq_governor *cpufreq_default_governor(void)
+{
+	return &schedutil_gov;
+}
+#endif
+
+cpufreq_governor_init(schedutil_gov);
+
+#ifdef CONFIG_ENERGY_MODEL
+static void rebuild_sd_workfn(struct work_struct *work)
+{
+	rebuild_sched_domains_energy();
+}
+static DECLARE_WORK(rebuild_sd_work, rebuild_sd_workfn);
+
+/*
+ * EAS shouldn't be attempted without sugov, so rebuild the sched_domains
+ * on governor changes to make sure the scheduler knows about it.
+ */
+void sched_cpufreq_governor_change(struct cpufreq_policy *policy,
+				  struct cpufreq_governor *old_gov)
+{
+	if (old_gov == &schedutil_gov || policy->governor == &schedutil_gov) {
+		/*
+		 * When called from the cpufreq_register_driver() path, the
+		 * cpu_hotplug_lock is already held, so use a work item to
+		 * avoid nested locking in rebuild_sched_domains().
+		 */
+		schedule_work(&rebuild_sd_work);
+	}
+
+}
+#endif
diff --git a/kernel/sched/cpupri.c b/kernel/sched/cpupri.c
new file mode 100644
index 0000000000..42c40cfdf8
--- /dev/null
+++ b/kernel/sched/cpupri.c
@@ -0,0 +1,316 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  kernel/sched/cpupri.c
+ *
+ *  CPU priority management
+ *
+ *  Copyright (C) 2007-2008 Novell
+ *
+ *  Author: Gregory Haskins <ghaskins@novell.com>
+ *
+ *  This code tracks the priority of each CPU so that global migration
+ *  decisions are easy to calculate.  Each CPU can be in a state as follows:
+ *
+ *                 (INVALID), NORMAL, RT1, ... RT99, HIGHER
+ *
+ *  going from the lowest priority to the highest.  CPUs in the INVALID state
+ *  are not eligible for routing.  The system maintains this state with
+ *  a 2 dimensional bitmap (the first for priority class, the second for CPUs
+ *  in that class).  Therefore a typical application without affinity
+ *  restrictions can find a suitable CPU with O(1) complexity (e.g. two bit
+ *  searches).  For tasks with affinity restrictions, the algorithm has a
+ *  worst case complexity of O(min(101, nr_domcpus)), though the scenario that
+ *  yields the worst case search is fairly contrived.
+ */
+
+/*
+ * p->rt_priority   p->prio   newpri   cpupri
+ *
+ *				  -1       -1 (CPUPRI_INVALID)
+ *
+ *				  99        0 (CPUPRI_NORMAL)
+ *
+ *		1        98       98        1
+ *	      ...
+ *	       49        50       50       49
+ *	       50        49       49       50
+ *	      ...
+ *	       99         0        0       99
+ *
+ *				 100	  100 (CPUPRI_HIGHER)
+ */
+static int convert_prio(int prio)
+{
+	int cpupri;
+
+	switch (prio) {
+	case CPUPRI_INVALID:
+		cpupri = CPUPRI_INVALID;	/* -1 */
+		break;
+
+	case 0 ... 98:
+		cpupri = MAX_RT_PRIO-1 - prio;	/* 1 ... 99 */
+		break;
+
+	case MAX_RT_PRIO-1:
+		cpupri = CPUPRI_NORMAL;		/*  0 */
+		break;
+
+	case MAX_RT_PRIO:
+		cpupri = CPUPRI_HIGHER;		/* 100 */
+		break;
+	}
+
+	return cpupri;
+}
+
+static inline int __cpupri_find(struct cpupri *cp, struct task_struct *p,
+				struct cpumask *lowest_mask, int idx)
+{
+	struct cpupri_vec *vec  = &cp->pri_to_cpu[idx];
+	int skip = 0;
+
+	if (!atomic_read(&(vec)->count))
+		skip = 1;
+	/*
+	 * When looking at the vector, we need to read the counter,
+	 * do a memory barrier, then read the mask.
+	 *
+	 * Note: This is still all racy, but we can deal with it.
+	 *  Ideally, we only want to look at masks that are set.
+	 *
+	 *  If a mask is not set, then the only thing wrong is that we
+	 *  did a little more work than necessary.
+	 *
+	 *  If we read a zero count but the mask is set, because of the
+	 *  memory barriers, that can only happen when the highest prio
+	 *  task for a run queue has left the run queue, in which case,
+	 *  it will be followed by a pull. If the task we are processing
+	 *  fails to find a proper place to go, that pull request will
+	 *  pull this task if the run queue is running at a lower
+	 *  priority.
+	 */
+	smp_rmb();
+
+	/* Need to do the rmb for every iteration */
+	if (skip)
+		return 0;
+
+	if (cpumask_any_and(&p->cpus_mask, vec->mask) >= nr_cpu_ids)
+		return 0;
+
+	if (lowest_mask) {
+		cpumask_and(lowest_mask, &p->cpus_mask, vec->mask);
+		cpumask_and(lowest_mask, lowest_mask, cpu_active_mask);
+
+		/*
+		 * We have to ensure that we have at least one bit
+		 * still set in the array, since the map could have
+		 * been concurrently emptied between the first and
+		 * second reads of vec->mask.  If we hit this
+		 * condition, simply act as though we never hit this
+		 * priority level and continue on.
+		 */
+		if (cpumask_empty(lowest_mask))
+			return 0;
+	}
+
+	return 1;
+}
+
+int cpupri_find(struct cpupri *cp, struct task_struct *p,
+		struct cpumask *lowest_mask)
+{
+	return cpupri_find_fitness(cp, p, lowest_mask, NULL);
+}
+
+/**
+ * cpupri_find_fitness - find the best (lowest-pri) CPU in the system
+ * @cp: The cpupri context
+ * @p: The task
+ * @lowest_mask: A mask to fill in with selected CPUs (or NULL)
+ * @fitness_fn: A pointer to a function to do custom checks whether the CPU
+ *              fits a specific criteria so that we only return those CPUs.
+ *
+ * Note: This function returns the recommended CPUs as calculated during the
+ * current invocation.  By the time the call returns, the CPUs may have in
+ * fact changed priorities any number of times.  While not ideal, it is not
+ * an issue of correctness since the normal rebalancer logic will correct
+ * any discrepancies created by racing against the uncertainty of the current
+ * priority configuration.
+ *
+ * Return: (int)bool - CPUs were found
+ */
+int cpupri_find_fitness(struct cpupri *cp, struct task_struct *p,
+		struct cpumask *lowest_mask,
+		bool (*fitness_fn)(struct task_struct *p, int cpu))
+{
+	int task_pri = convert_prio(p->prio);
+	int idx, cpu;
+
+	WARN_ON_ONCE(task_pri >= CPUPRI_NR_PRIORITIES);
+
+	for (idx = 0; idx < task_pri; idx++) {
+
+		if (!__cpupri_find(cp, p, lowest_mask, idx))
+			continue;
+
+		if (!lowest_mask || !fitness_fn)
+			return 1;
+
+		/* Ensure the capacity of the CPUs fit the task */
+		for_each_cpu(cpu, lowest_mask) {
+			if (!fitness_fn(p, cpu))
+				cpumask_clear_cpu(cpu, lowest_mask);
+		}
+
+		/*
+		 * If no CPU at the current priority can fit the task
+		 * continue looking
+		 */
+		if (cpumask_empty(lowest_mask))
+			continue;
+
+		return 1;
+	}
+
+	/*
+	 * If we failed to find a fitting lowest_mask, kick off a new search
+	 * but without taking into account any fitness criteria this time.
+	 *
+	 * This rule favours honouring priority over fitting the task in the
+	 * correct CPU (Capacity Awareness being the only user now).
+	 * The idea is that if a higher priority task can run, then it should
+	 * run even if this ends up being on unfitting CPU.
+	 *
+	 * The cost of this trade-off is not entirely clear and will probably
+	 * be good for some workloads and bad for others.
+	 *
+	 * The main idea here is that if some CPUs were over-committed, we try
+	 * to spread which is what the scheduler traditionally did. Sys admins
+	 * must do proper RT planning to avoid overloading the system if they
+	 * really care.
+	 */
+	if (fitness_fn)
+		return cpupri_find(cp, p, lowest_mask);
+
+	return 0;
+}
+
+/**
+ * cpupri_set - update the CPU priority setting
+ * @cp: The cpupri context
+ * @cpu: The target CPU
+ * @newpri: The priority (INVALID,NORMAL,RT1-RT99,HIGHER) to assign to this CPU
+ *
+ * Note: Assumes cpu_rq(cpu)->lock is locked
+ *
+ * Returns: (void)
+ */
+void cpupri_set(struct cpupri *cp, int cpu, int newpri)
+{
+	int *currpri = &cp->cpu_to_pri[cpu];
+	int oldpri = *currpri;
+	int do_mb = 0;
+
+	newpri = convert_prio(newpri);
+
+	BUG_ON(newpri >= CPUPRI_NR_PRIORITIES);
+
+	if (newpri == oldpri)
+		return;
+
+	/*
+	 * If the CPU was currently mapped to a different value, we
+	 * need to map it to the new value then remove the old value.
+	 * Note, we must add the new value first, otherwise we risk the
+	 * cpu being missed by the priority loop in cpupri_find.
+	 */
+	if (likely(newpri != CPUPRI_INVALID)) {
+		struct cpupri_vec *vec = &cp->pri_to_cpu[newpri];
+
+		cpumask_set_cpu(cpu, vec->mask);
+		/*
+		 * When adding a new vector, we update the mask first,
+		 * do a write memory barrier, and then update the count, to
+		 * make sure the vector is visible when count is set.
+		 */
+		smp_mb__before_atomic();
+		atomic_inc(&(vec)->count);
+		do_mb = 1;
+	}
+	if (likely(oldpri != CPUPRI_INVALID)) {
+		struct cpupri_vec *vec  = &cp->pri_to_cpu[oldpri];
+
+		/*
+		 * Because the order of modification of the vec->count
+		 * is important, we must make sure that the update
+		 * of the new prio is seen before we decrement the
+		 * old prio. This makes sure that the loop sees
+		 * one or the other when we raise the priority of
+		 * the run queue. We don't care about when we lower the
+		 * priority, as that will trigger an rt pull anyway.
+		 *
+		 * We only need to do a memory barrier if we updated
+		 * the new priority vec.
+		 */
+		if (do_mb)
+			smp_mb__after_atomic();
+
+		/*
+		 * When removing from the vector, we decrement the counter first
+		 * do a memory barrier and then clear the mask.
+		 */
+		atomic_dec(&(vec)->count);
+		smp_mb__after_atomic();
+		cpumask_clear_cpu(cpu, vec->mask);
+	}
+
+	*currpri = newpri;
+}
+
+/**
+ * cpupri_init - initialize the cpupri structure
+ * @cp: The cpupri context
+ *
+ * Return: -ENOMEM on memory allocation failure.
+ */
+int cpupri_init(struct cpupri *cp)
+{
+	int i;
+
+	for (i = 0; i < CPUPRI_NR_PRIORITIES; i++) {
+		struct cpupri_vec *vec = &cp->pri_to_cpu[i];
+
+		atomic_set(&vec->count, 0);
+		if (!zalloc_cpumask_var(&vec->mask, GFP_KERNEL))
+			goto cleanup;
+	}
+
+	cp->cpu_to_pri = kcalloc(nr_cpu_ids, sizeof(int), GFP_KERNEL);
+	if (!cp->cpu_to_pri)
+		goto cleanup;
+
+	for_each_possible_cpu(i)
+		cp->cpu_to_pri[i] = CPUPRI_INVALID;
+
+	return 0;
+
+cleanup:
+	for (i--; i >= 0; i--)
+		free_cpumask_var(cp->pri_to_cpu[i].mask);
+	return -ENOMEM;
+}
+
+/**
+ * cpupri_cleanup - clean up the cpupri structure
+ * @cp: The cpupri context
+ */
+void cpupri_cleanup(struct cpupri *cp)
+{
+	int i;
+
+	kfree(cp->cpu_to_pri);
+	for (i = 0; i < CPUPRI_NR_PRIORITIES; i++)
+		free_cpumask_var(cp->pri_to_cpu[i].mask);
+}
diff --git a/kernel/sched/cpupri.h b/kernel/sched/cpupri.h
new file mode 100644
index 0000000000..d6cba00200
--- /dev/null
+++ b/kernel/sched/cpupri.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#define CPUPRI_NR_PRIORITIES	(MAX_RT_PRIO+1)
+
+#define CPUPRI_INVALID		-1
+#define CPUPRI_NORMAL		 0
+/* values 1-99 are for RT1-RT99 priorities */
+#define CPUPRI_HIGHER		100
+
+struct cpupri_vec {
+	atomic_t		count;
+	cpumask_var_t		mask;
+};
+
+struct cpupri {
+	struct cpupri_vec	pri_to_cpu[CPUPRI_NR_PRIORITIES];
+	int			*cpu_to_pri;
+};
+
+#ifdef CONFIG_SMP
+int  cpupri_find(struct cpupri *cp, struct task_struct *p,
+		 struct cpumask *lowest_mask);
+int  cpupri_find_fitness(struct cpupri *cp, struct task_struct *p,
+			 struct cpumask *lowest_mask,
+			 bool (*fitness_fn)(struct task_struct *p, int cpu));
+void cpupri_set(struct cpupri *cp, int cpu, int pri);
+int  cpupri_init(struct cpupri *cp);
+void cpupri_cleanup(struct cpupri *cp);
+#endif
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
new file mode 100644
index 0000000000..af7952f12e
--- /dev/null
+++ b/kernel/sched/cputime.c
@@ -0,0 +1,1102 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Simple CPU accounting cgroup controller
+ */
+
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
+ #include <asm/cputime.h>
+#endif
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+
+/*
+ * There are no locks covering percpu hardirq/softirq time.
+ * They are only modified in vtime_account, on corresponding CPU
+ * with interrupts disabled. So, writes are safe.
+ * They are read and saved off onto struct rq in update_rq_clock().
+ * This may result in other CPU reading this CPU's irq time and can
+ * race with irq/vtime_account on this CPU. We would either get old
+ * or new value with a side effect of accounting a slice of irq time to wrong
+ * task when irq is in progress while we read rq->clock. That is a worthy
+ * compromise in place of having locks on each irq in account_system_time.
+ */
+DEFINE_PER_CPU(struct irqtime, cpu_irqtime);
+
+static int sched_clock_irqtime;
+
+void enable_sched_clock_irqtime(void)
+{
+	sched_clock_irqtime = 1;
+}
+
+void disable_sched_clock_irqtime(void)
+{
+	sched_clock_irqtime = 0;
+}
+
+static void irqtime_account_delta(struct irqtime *irqtime, u64 delta,
+				  enum cpu_usage_stat idx)
+{
+	u64 *cpustat = kcpustat_this_cpu->cpustat;
+
+	u64_stats_update_begin(&irqtime->sync);
+	cpustat[idx] += delta;
+	irqtime->total += delta;
+	irqtime->tick_delta += delta;
+	u64_stats_update_end(&irqtime->sync);
+}
+
+/*
+ * Called after incrementing preempt_count on {soft,}irq_enter
+ * and before decrementing preempt_count on {soft,}irq_exit.
+ */
+void irqtime_account_irq(struct task_struct *curr, unsigned int offset)
+{
+	struct irqtime *irqtime = this_cpu_ptr(&cpu_irqtime);
+	unsigned int pc;
+	s64 delta;
+	int cpu;
+
+	if (!sched_clock_irqtime)
+		return;
+
+	cpu = smp_processor_id();
+	delta = sched_clock_cpu(cpu) - irqtime->irq_start_time;
+	irqtime->irq_start_time += delta;
+	pc = irq_count() - offset;
+
+	/*
+	 * We do not account for softirq time from ksoftirqd here.
+	 * We want to continue accounting softirq time to ksoftirqd thread
+	 * in that case, so as not to confuse scheduler with a special task
+	 * that do not consume any time, but still wants to run.
+	 */
+	if (pc & HARDIRQ_MASK)
+		irqtime_account_delta(irqtime, delta, CPUTIME_IRQ);
+	else if ((pc & SOFTIRQ_OFFSET) && curr != this_cpu_ksoftirqd())
+		irqtime_account_delta(irqtime, delta, CPUTIME_SOFTIRQ);
+}
+
+static u64 irqtime_tick_accounted(u64 maxtime)
+{
+	struct irqtime *irqtime = this_cpu_ptr(&cpu_irqtime);
+	u64 delta;
+
+	delta = min(irqtime->tick_delta, maxtime);
+	irqtime->tick_delta -= delta;
+
+	return delta;
+}
+
+#else /* CONFIG_IRQ_TIME_ACCOUNTING */
+
+#define sched_clock_irqtime	(0)
+
+static u64 irqtime_tick_accounted(u64 dummy)
+{
+	return 0;
+}
+
+#endif /* !CONFIG_IRQ_TIME_ACCOUNTING */
+
+static inline void task_group_account_field(struct task_struct *p, int index,
+					    u64 tmp)
+{
+	/*
+	 * Since all updates are sure to touch the root cgroup, we
+	 * get ourselves ahead and touch it first. If the root cgroup
+	 * is the only cgroup, then nothing else should be necessary.
+	 *
+	 */
+	__this_cpu_add(kernel_cpustat.cpustat[index], tmp);
+
+	cgroup_account_cputime_field(p, index, tmp);
+}
+
+/*
+ * Account user CPU time to a process.
+ * @p: the process that the CPU time gets accounted to
+ * @cputime: the CPU time spent in user space since the last update
+ */
+void account_user_time(struct task_struct *p, u64 cputime)
+{
+	int index;
+
+	/* Add user time to process. */
+	p->utime += cputime;
+	account_group_user_time(p, cputime);
+
+	index = (task_nice(p) > 0) ? CPUTIME_NICE : CPUTIME_USER;
+
+	/* Add user time to cpustat. */
+	task_group_account_field(p, index, cputime);
+
+	/* Account for user time used */
+	acct_account_cputime(p);
+}
+
+/*
+ * Account guest CPU time to a process.
+ * @p: the process that the CPU time gets accounted to
+ * @cputime: the CPU time spent in virtual machine since the last update
+ */
+void account_guest_time(struct task_struct *p, u64 cputime)
+{
+	u64 *cpustat = kcpustat_this_cpu->cpustat;
+
+	/* Add guest time to process. */
+	p->utime += cputime;
+	account_group_user_time(p, cputime);
+	p->gtime += cputime;
+
+	/* Add guest time to cpustat. */
+	if (task_nice(p) > 0) {
+		task_group_account_field(p, CPUTIME_NICE, cputime);
+		cpustat[CPUTIME_GUEST_NICE] += cputime;
+	} else {
+		task_group_account_field(p, CPUTIME_USER, cputime);
+		cpustat[CPUTIME_GUEST] += cputime;
+	}
+}
+
+/*
+ * Account system CPU time to a process and desired cpustat field
+ * @p: the process that the CPU time gets accounted to
+ * @cputime: the CPU time spent in kernel space since the last update
+ * @index: pointer to cpustat field that has to be updated
+ */
+void account_system_index_time(struct task_struct *p,
+			       u64 cputime, enum cpu_usage_stat index)
+{
+	/* Add system time to process. */
+	p->stime += cputime;
+	account_group_system_time(p, cputime);
+
+	/* Add system time to cpustat. */
+	task_group_account_field(p, index, cputime);
+
+	/* Account for system time used */
+	acct_account_cputime(p);
+}
+
+/*
+ * Account system CPU time to a process.
+ * @p: the process that the CPU time gets accounted to
+ * @hardirq_offset: the offset to subtract from hardirq_count()
+ * @cputime: the CPU time spent in kernel space since the last update
+ */
+void account_system_time(struct task_struct *p, int hardirq_offset, u64 cputime)
+{
+	int index;
+
+	if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
+		account_guest_time(p, cputime);
+		return;
+	}
+
+	if (hardirq_count() - hardirq_offset)
+		index = CPUTIME_IRQ;
+	else if (in_serving_softirq())
+		index = CPUTIME_SOFTIRQ;
+	else
+		index = CPUTIME_SYSTEM;
+
+	account_system_index_time(p, cputime, index);
+}
+
+/*
+ * Account for involuntary wait time.
+ * @cputime: the CPU time spent in involuntary wait
+ */
+void account_steal_time(u64 cputime)
+{
+	u64 *cpustat = kcpustat_this_cpu->cpustat;
+
+	cpustat[CPUTIME_STEAL] += cputime;
+}
+
+/*
+ * Account for idle time.
+ * @cputime: the CPU time spent in idle wait
+ */
+void account_idle_time(u64 cputime)
+{
+	u64 *cpustat = kcpustat_this_cpu->cpustat;
+	struct rq *rq = this_rq();
+
+	if (atomic_read(&rq->nr_iowait) > 0)
+		cpustat[CPUTIME_IOWAIT] += cputime;
+	else
+		cpustat[CPUTIME_IDLE] += cputime;
+}
+
+
+#ifdef CONFIG_SCHED_CORE
+/*
+ * Account for forceidle time due to core scheduling.
+ *
+ * REQUIRES: schedstat is enabled.
+ */
+void __account_forceidle_time(struct task_struct *p, u64 delta)
+{
+	__schedstat_add(p->stats.core_forceidle_sum, delta);
+
+	task_group_account_field(p, CPUTIME_FORCEIDLE, delta);
+}
+#endif
+
+/*
+ * When a guest is interrupted for a longer amount of time, missed clock
+ * ticks are not redelivered later. Due to that, this function may on
+ * occasion account more time than the calling functions think elapsed.
+ */
+static __always_inline u64 steal_account_process_time(u64 maxtime)
+{
+#ifdef CONFIG_PARAVIRT
+	if (static_key_false(&paravirt_steal_enabled)) {
+		u64 steal;
+
+		steal = paravirt_steal_clock(smp_processor_id());
+		steal -= this_rq()->prev_steal_time;
+		steal = min(steal, maxtime);
+		account_steal_time(steal);
+		this_rq()->prev_steal_time += steal;
+
+		return steal;
+	}
+#endif
+	return 0;
+}
+
+/*
+ * Account how much elapsed time was spent in steal, irq, or softirq time.
+ */
+static inline u64 account_other_time(u64 max)
+{
+	u64 accounted;
+
+	lockdep_assert_irqs_disabled();
+
+	accounted = steal_account_process_time(max);
+
+	if (accounted < max)
+		accounted += irqtime_tick_accounted(max - accounted);
+
+	return accounted;
+}
+
+#ifdef CONFIG_64BIT
+static inline u64 read_sum_exec_runtime(struct task_struct *t)
+{
+	return t->se.sum_exec_runtime;
+}
+#else
+static u64 read_sum_exec_runtime(struct task_struct *t)
+{
+	u64 ns;
+	struct rq_flags rf;
+	struct rq *rq;
+
+	rq = task_rq_lock(t, &rf);
+	ns = t->se.sum_exec_runtime;
+	task_rq_unlock(rq, t, &rf);
+
+	return ns;
+}
+#endif
+
+/*
+ * Accumulate raw cputime values of dead tasks (sig->[us]time) and live
+ * tasks (sum on group iteration) belonging to @tsk's group.
+ */
+void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
+{
+	struct signal_struct *sig = tsk->signal;
+	u64 utime, stime;
+	struct task_struct *t;
+	unsigned int seq, nextseq;
+	unsigned long flags;
+
+	/*
+	 * Update current task runtime to account pending time since last
+	 * scheduler action or thread_group_cputime() call. This thread group
+	 * might have other running tasks on different CPUs, but updating
+	 * their runtime can affect syscall performance, so we skip account
+	 * those pending times and rely only on values updated on tick or
+	 * other scheduler action.
+	 */
+	if (same_thread_group(current, tsk))
+		(void) task_sched_runtime(current);
+
+	rcu_read_lock();
+	/* Attempt a lockless read on the first round. */
+	nextseq = 0;
+	do {
+		seq = nextseq;
+		flags = read_seqbegin_or_lock_irqsave(&sig->stats_lock, &seq);
+		times->utime = sig->utime;
+		times->stime = sig->stime;
+		times->sum_exec_runtime = sig->sum_sched_runtime;
+
+		for_each_thread(tsk, t) {
+			task_cputime(t, &utime, &stime);
+			times->utime += utime;
+			times->stime += stime;
+			times->sum_exec_runtime += read_sum_exec_runtime(t);
+		}
+		/* If lockless access failed, take the lock. */
+		nextseq = 1;
+	} while (need_seqretry(&sig->stats_lock, seq));
+	done_seqretry_irqrestore(&sig->stats_lock, seq, flags);
+	rcu_read_unlock();
+}
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+/*
+ * Account a tick to a process and cpustat
+ * @p: the process that the CPU time gets accounted to
+ * @user_tick: is the tick from userspace
+ * @rq: the pointer to rq
+ *
+ * Tick demultiplexing follows the order
+ * - pending hardirq update
+ * - pending softirq update
+ * - user_time
+ * - idle_time
+ * - system time
+ *   - check for guest_time
+ *   - else account as system_time
+ *
+ * Check for hardirq is done both for system and user time as there is
+ * no timer going off while we are on hardirq and hence we may never get an
+ * opportunity to update it solely in system time.
+ * p->stime and friends are only updated on system time and not on irq
+ * softirq as those do not count in task exec_runtime any more.
+ */
+static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
+					 int ticks)
+{
+	u64 other, cputime = TICK_NSEC * ticks;
+
+	/*
+	 * When returning from idle, many ticks can get accounted at
+	 * once, including some ticks of steal, irq, and softirq time.
+	 * Subtract those ticks from the amount of time accounted to
+	 * idle, or potentially user or system time. Due to rounding,
+	 * other time can exceed ticks occasionally.
+	 */
+	other = account_other_time(ULONG_MAX);
+	if (other >= cputime)
+		return;
+
+	cputime -= other;
+
+	if (this_cpu_ksoftirqd() == p) {
+		/*
+		 * ksoftirqd time do not get accounted in cpu_softirq_time.
+		 * So, we have to handle it separately here.
+		 * Also, p->stime needs to be updated for ksoftirqd.
+		 */
+		account_system_index_time(p, cputime, CPUTIME_SOFTIRQ);
+	} else if (user_tick) {
+		account_user_time(p, cputime);
+	} else if (p == this_rq()->idle) {
+		account_idle_time(cputime);
+	} else if (p->flags & PF_VCPU) { /* System time or guest time */
+		account_guest_time(p, cputime);
+	} else {
+		account_system_index_time(p, cputime, CPUTIME_SYSTEM);
+	}
+}
+
+static void irqtime_account_idle_ticks(int ticks)
+{
+	irqtime_account_process_tick(current, 0, ticks);
+}
+#else /* CONFIG_IRQ_TIME_ACCOUNTING */
+static inline void irqtime_account_idle_ticks(int ticks) { }
+static inline void irqtime_account_process_tick(struct task_struct *p, int user_tick,
+						int nr_ticks) { }
+#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
+
+/*
+ * Use precise platform statistics if available:
+ */
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
+
+# ifndef __ARCH_HAS_VTIME_TASK_SWITCH
+void vtime_task_switch(struct task_struct *prev)
+{
+	if (is_idle_task(prev))
+		vtime_account_idle(prev);
+	else
+		vtime_account_kernel(prev);
+
+	vtime_flush(prev);
+	arch_vtime_task_switch(prev);
+}
+# endif
+
+void vtime_account_irq(struct task_struct *tsk, unsigned int offset)
+{
+	unsigned int pc = irq_count() - offset;
+
+	if (pc & HARDIRQ_OFFSET) {
+		vtime_account_hardirq(tsk);
+	} else if (pc & SOFTIRQ_OFFSET) {
+		vtime_account_softirq(tsk);
+	} else if (!IS_ENABLED(CONFIG_HAVE_VIRT_CPU_ACCOUNTING_IDLE) &&
+		   is_idle_task(tsk)) {
+		vtime_account_idle(tsk);
+	} else {
+		vtime_account_kernel(tsk);
+	}
+}
+
+void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev,
+		    u64 *ut, u64 *st)
+{
+	*ut = curr->utime;
+	*st = curr->stime;
+}
+
+void task_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st)
+{
+	*ut = p->utime;
+	*st = p->stime;
+}
+EXPORT_SYMBOL_GPL(task_cputime_adjusted);
+
+void thread_group_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st)
+{
+	struct task_cputime cputime;
+
+	thread_group_cputime(p, &cputime);
+
+	*ut = cputime.utime;
+	*st = cputime.stime;
+}
+
+#else /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE: */
+
+/*
+ * Account a single tick of CPU time.
+ * @p: the process that the CPU time gets accounted to
+ * @user_tick: indicates if the tick is a user or a system tick
+ */
+void account_process_tick(struct task_struct *p, int user_tick)
+{
+	u64 cputime, steal;
+
+	if (vtime_accounting_enabled_this_cpu())
+		return;
+
+	if (sched_clock_irqtime) {
+		irqtime_account_process_tick(p, user_tick, 1);
+		return;
+	}
+
+	cputime = TICK_NSEC;
+	steal = steal_account_process_time(ULONG_MAX);
+
+	if (steal >= cputime)
+		return;
+
+	cputime -= steal;
+
+	if (user_tick)
+		account_user_time(p, cputime);
+	else if ((p != this_rq()->idle) || (irq_count() != HARDIRQ_OFFSET))
+		account_system_time(p, HARDIRQ_OFFSET, cputime);
+	else
+		account_idle_time(cputime);
+}
+
+/*
+ * Account multiple ticks of idle time.
+ * @ticks: number of stolen ticks
+ */
+void account_idle_ticks(unsigned long ticks)
+{
+	u64 cputime, steal;
+
+	if (sched_clock_irqtime) {
+		irqtime_account_idle_ticks(ticks);
+		return;
+	}
+
+	cputime = ticks * TICK_NSEC;
+	steal = steal_account_process_time(ULONG_MAX);
+
+	if (steal >= cputime)
+		return;
+
+	cputime -= steal;
+	account_idle_time(cputime);
+}
+
+/*
+ * Adjust tick based cputime random precision against scheduler runtime
+ * accounting.
+ *
+ * Tick based cputime accounting depend on random scheduling timeslices of a
+ * task to be interrupted or not by the timer.  Depending on these
+ * circumstances, the number of these interrupts may be over or
+ * under-optimistic, matching the real user and system cputime with a variable
+ * precision.
+ *
+ * Fix this by scaling these tick based values against the total runtime
+ * accounted by the CFS scheduler.
+ *
+ * This code provides the following guarantees:
+ *
+ *   stime + utime == rtime
+ *   stime_i+1 >= stime_i, utime_i+1 >= utime_i
+ *
+ * Assuming that rtime_i+1 >= rtime_i.
+ */
+void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev,
+		    u64 *ut, u64 *st)
+{
+	u64 rtime, stime, utime;
+	unsigned long flags;
+
+	/* Serialize concurrent callers such that we can honour our guarantees */
+	raw_spin_lock_irqsave(&prev->lock, flags);
+	rtime = curr->sum_exec_runtime;
+
+	/*
+	 * This is possible under two circumstances:
+	 *  - rtime isn't monotonic after all (a bug);
+	 *  - we got reordered by the lock.
+	 *
+	 * In both cases this acts as a filter such that the rest of the code
+	 * can assume it is monotonic regardless of anything else.
+	 */
+	if (prev->stime + prev->utime >= rtime)
+		goto out;
+
+	stime = curr->stime;
+	utime = curr->utime;
+
+	/*
+	 * If either stime or utime are 0, assume all runtime is userspace.
+	 * Once a task gets some ticks, the monotonicity code at 'update:'
+	 * will ensure things converge to the observed ratio.
+	 */
+	if (stime == 0) {
+		utime = rtime;
+		goto update;
+	}
+
+	if (utime == 0) {
+		stime = rtime;
+		goto update;
+	}
+
+	stime = mul_u64_u64_div_u64(stime, rtime, stime + utime);
+
+update:
+	/*
+	 * Make sure stime doesn't go backwards; this preserves monotonicity
+	 * for utime because rtime is monotonic.
+	 *
+	 *  utime_i+1 = rtime_i+1 - stime_i
+	 *            = rtime_i+1 - (rtime_i - utime_i)
+	 *            = (rtime_i+1 - rtime_i) + utime_i
+	 *            >= utime_i
+	 */
+	if (stime < prev->stime)
+		stime = prev->stime;
+	utime = rtime - stime;
+
+	/*
+	 * Make sure utime doesn't go backwards; this still preserves
+	 * monotonicity for stime, analogous argument to above.
+	 */
+	if (utime < prev->utime) {
+		utime = prev->utime;
+		stime = rtime - utime;
+	}
+
+	prev->stime = stime;
+	prev->utime = utime;
+out:
+	*ut = prev->utime;
+	*st = prev->stime;
+	raw_spin_unlock_irqrestore(&prev->lock, flags);
+}
+
+void task_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st)
+{
+	struct task_cputime cputime = {
+		.sum_exec_runtime = p->se.sum_exec_runtime,
+	};
+
+	if (task_cputime(p, &cputime.utime, &cputime.stime))
+		cputime.sum_exec_runtime = task_sched_runtime(p);
+	cputime_adjust(&cputime, &p->prev_cputime, ut, st);
+}
+EXPORT_SYMBOL_GPL(task_cputime_adjusted);
+
+void thread_group_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st)
+{
+	struct task_cputime cputime;
+
+	thread_group_cputime(p, &cputime);
+	cputime_adjust(&cputime, &p->signal->prev_cputime, ut, st);
+}
+#endif /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
+
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
+static u64 vtime_delta(struct vtime *vtime)
+{
+	unsigned long long clock;
+
+	clock = sched_clock();
+	if (clock < vtime->starttime)
+		return 0;
+
+	return clock - vtime->starttime;
+}
+
+static u64 get_vtime_delta(struct vtime *vtime)
+{
+	u64 delta = vtime_delta(vtime);
+	u64 other;
+
+	/*
+	 * Unlike tick based timing, vtime based timing never has lost
+	 * ticks, and no need for steal time accounting to make up for
+	 * lost ticks. Vtime accounts a rounded version of actual
+	 * elapsed time. Limit account_other_time to prevent rounding
+	 * errors from causing elapsed vtime to go negative.
+	 */
+	other = account_other_time(delta);
+	WARN_ON_ONCE(vtime->state == VTIME_INACTIVE);
+	vtime->starttime += delta;
+
+	return delta - other;
+}
+
+static void vtime_account_system(struct task_struct *tsk,
+				 struct vtime *vtime)
+{
+	vtime->stime += get_vtime_delta(vtime);
+	if (vtime->stime >= TICK_NSEC) {
+		account_system_time(tsk, irq_count(), vtime->stime);
+		vtime->stime = 0;
+	}
+}
+
+static void vtime_account_guest(struct task_struct *tsk,
+				struct vtime *vtime)
+{
+	vtime->gtime += get_vtime_delta(vtime);
+	if (vtime->gtime >= TICK_NSEC) {
+		account_guest_time(tsk, vtime->gtime);
+		vtime->gtime = 0;
+	}
+}
+
+static void __vtime_account_kernel(struct task_struct *tsk,
+				   struct vtime *vtime)
+{
+	/* We might have scheduled out from guest path */
+	if (vtime->state == VTIME_GUEST)
+		vtime_account_guest(tsk, vtime);
+	else
+		vtime_account_system(tsk, vtime);
+}
+
+void vtime_account_kernel(struct task_struct *tsk)
+{
+	struct vtime *vtime = &tsk->vtime;
+
+	if (!vtime_delta(vtime))
+		return;
+
+	write_seqcount_begin(&vtime->seqcount);
+	__vtime_account_kernel(tsk, vtime);
+	write_seqcount_end(&vtime->seqcount);
+}
+
+void vtime_user_enter(struct task_struct *tsk)
+{
+	struct vtime *vtime = &tsk->vtime;
+
+	write_seqcount_begin(&vtime->seqcount);
+	vtime_account_system(tsk, vtime);
+	vtime->state = VTIME_USER;
+	write_seqcount_end(&vtime->seqcount);
+}
+
+void vtime_user_exit(struct task_struct *tsk)
+{
+	struct vtime *vtime = &tsk->vtime;
+
+	write_seqcount_begin(&vtime->seqcount);
+	vtime->utime += get_vtime_delta(vtime);
+	if (vtime->utime >= TICK_NSEC) {
+		account_user_time(tsk, vtime->utime);
+		vtime->utime = 0;
+	}
+	vtime->state = VTIME_SYS;
+	write_seqcount_end(&vtime->seqcount);
+}
+
+void vtime_guest_enter(struct task_struct *tsk)
+{
+	struct vtime *vtime = &tsk->vtime;
+	/*
+	 * The flags must be updated under the lock with
+	 * the vtime_starttime flush and update.
+	 * That enforces a right ordering and update sequence
+	 * synchronization against the reader (task_gtime())
+	 * that can thus safely catch up with a tickless delta.
+	 */
+	write_seqcount_begin(&vtime->seqcount);
+	vtime_account_system(tsk, vtime);
+	tsk->flags |= PF_VCPU;
+	vtime->state = VTIME_GUEST;
+	write_seqcount_end(&vtime->seqcount);
+}
+EXPORT_SYMBOL_GPL(vtime_guest_enter);
+
+void vtime_guest_exit(struct task_struct *tsk)
+{
+	struct vtime *vtime = &tsk->vtime;
+
+	write_seqcount_begin(&vtime->seqcount);
+	vtime_account_guest(tsk, vtime);
+	tsk->flags &= ~PF_VCPU;
+	vtime->state = VTIME_SYS;
+	write_seqcount_end(&vtime->seqcount);
+}
+EXPORT_SYMBOL_GPL(vtime_guest_exit);
+
+void vtime_account_idle(struct task_struct *tsk)
+{
+	account_idle_time(get_vtime_delta(&tsk->vtime));
+}
+
+void vtime_task_switch_generic(struct task_struct *prev)
+{
+	struct vtime *vtime = &prev->vtime;
+
+	write_seqcount_begin(&vtime->seqcount);
+	if (vtime->state == VTIME_IDLE)
+		vtime_account_idle(prev);
+	else
+		__vtime_account_kernel(prev, vtime);
+	vtime->state = VTIME_INACTIVE;
+	vtime->cpu = -1;
+	write_seqcount_end(&vtime->seqcount);
+
+	vtime = &current->vtime;
+
+	write_seqcount_begin(&vtime->seqcount);
+	if (is_idle_task(current))
+		vtime->state = VTIME_IDLE;
+	else if (current->flags & PF_VCPU)
+		vtime->state = VTIME_GUEST;
+	else
+		vtime->state = VTIME_SYS;
+	vtime->starttime = sched_clock();
+	vtime->cpu = smp_processor_id();
+	write_seqcount_end(&vtime->seqcount);
+}
+
+void vtime_init_idle(struct task_struct *t, int cpu)
+{
+	struct vtime *vtime = &t->vtime;
+	unsigned long flags;
+
+	local_irq_save(flags);
+	write_seqcount_begin(&vtime->seqcount);
+	vtime->state = VTIME_IDLE;
+	vtime->starttime = sched_clock();
+	vtime->cpu = cpu;
+	write_seqcount_end(&vtime->seqcount);
+	local_irq_restore(flags);
+}
+
+u64 task_gtime(struct task_struct *t)
+{
+	struct vtime *vtime = &t->vtime;
+	unsigned int seq;
+	u64 gtime;
+
+	if (!vtime_accounting_enabled())
+		return t->gtime;
+
+	do {
+		seq = read_seqcount_begin(&vtime->seqcount);
+
+		gtime = t->gtime;
+		if (vtime->state == VTIME_GUEST)
+			gtime += vtime->gtime + vtime_delta(vtime);
+
+	} while (read_seqcount_retry(&vtime->seqcount, seq));
+
+	return gtime;
+}
+
+/*
+ * Fetch cputime raw values from fields of task_struct and
+ * add up the pending nohz execution time since the last
+ * cputime snapshot.
+ */
+bool task_cputime(struct task_struct *t, u64 *utime, u64 *stime)
+{
+	struct vtime *vtime = &t->vtime;
+	unsigned int seq;
+	u64 delta;
+	int ret;
+
+	if (!vtime_accounting_enabled()) {
+		*utime = t->utime;
+		*stime = t->stime;
+		return false;
+	}
+
+	do {
+		ret = false;
+		seq = read_seqcount_begin(&vtime->seqcount);
+
+		*utime = t->utime;
+		*stime = t->stime;
+
+		/* Task is sleeping or idle, nothing to add */
+		if (vtime->state < VTIME_SYS)
+			continue;
+
+		ret = true;
+		delta = vtime_delta(vtime);
+
+		/*
+		 * Task runs either in user (including guest) or kernel space,
+		 * add pending nohz time to the right place.
+		 */
+		if (vtime->state == VTIME_SYS)
+			*stime += vtime->stime + delta;
+		else
+			*utime += vtime->utime + delta;
+	} while (read_seqcount_retry(&vtime->seqcount, seq));
+
+	return ret;
+}
+
+static int vtime_state_fetch(struct vtime *vtime, int cpu)
+{
+	int state = READ_ONCE(vtime->state);
+
+	/*
+	 * We raced against a context switch, fetch the
+	 * kcpustat task again.
+	 */
+	if (vtime->cpu != cpu && vtime->cpu != -1)
+		return -EAGAIN;
+
+	/*
+	 * Two possible things here:
+	 * 1) We are seeing the scheduling out task (prev) or any past one.
+	 * 2) We are seeing the scheduling in task (next) but it hasn't
+	 *    passed though vtime_task_switch() yet so the pending
+	 *    cputime of the prev task may not be flushed yet.
+	 *
+	 * Case 1) is ok but 2) is not. So wait for a safe VTIME state.
+	 */
+	if (state == VTIME_INACTIVE)
+		return -EAGAIN;
+
+	return state;
+}
+
+static u64 kcpustat_user_vtime(struct vtime *vtime)
+{
+	if (vtime->state == VTIME_USER)
+		return vtime->utime + vtime_delta(vtime);
+	else if (vtime->state == VTIME_GUEST)
+		return vtime->gtime + vtime_delta(vtime);
+	return 0;
+}
+
+static int kcpustat_field_vtime(u64 *cpustat,
+				struct task_struct *tsk,
+				enum cpu_usage_stat usage,
+				int cpu, u64 *val)
+{
+	struct vtime *vtime = &tsk->vtime;
+	unsigned int seq;
+
+	do {
+		int state;
+
+		seq = read_seqcount_begin(&vtime->seqcount);
+
+		state = vtime_state_fetch(vtime, cpu);
+		if (state < 0)
+			return state;
+
+		*val = cpustat[usage];
+
+		/*
+		 * Nice VS unnice cputime accounting may be inaccurate if
+		 * the nice value has changed since the last vtime update.
+		 * But proper fix would involve interrupting target on nice
+		 * updates which is a no go on nohz_full (although the scheduler
+		 * may still interrupt the target if rescheduling is needed...)
+		 */
+		switch (usage) {
+		case CPUTIME_SYSTEM:
+			if (state == VTIME_SYS)
+				*val += vtime->stime + vtime_delta(vtime);
+			break;
+		case CPUTIME_USER:
+			if (task_nice(tsk) <= 0)
+				*val += kcpustat_user_vtime(vtime);
+			break;
+		case CPUTIME_NICE:
+			if (task_nice(tsk) > 0)
+				*val += kcpustat_user_vtime(vtime);
+			break;
+		case CPUTIME_GUEST:
+			if (state == VTIME_GUEST && task_nice(tsk) <= 0)
+				*val += vtime->gtime + vtime_delta(vtime);
+			break;
+		case CPUTIME_GUEST_NICE:
+			if (state == VTIME_GUEST && task_nice(tsk) > 0)
+				*val += vtime->gtime + vtime_delta(vtime);
+			break;
+		default:
+			break;
+		}
+	} while (read_seqcount_retry(&vtime->seqcount, seq));
+
+	return 0;
+}
+
+u64 kcpustat_field(struct kernel_cpustat *kcpustat,
+		   enum cpu_usage_stat usage, int cpu)
+{
+	u64 *cpustat = kcpustat->cpustat;
+	u64 val = cpustat[usage];
+	struct rq *rq;
+	int err;
+
+	if (!vtime_accounting_enabled_cpu(cpu))
+		return val;
+
+	rq = cpu_rq(cpu);
+
+	for (;;) {
+		struct task_struct *curr;
+
+		rcu_read_lock();
+		curr = rcu_dereference(rq->curr);
+		if (WARN_ON_ONCE(!curr)) {
+			rcu_read_unlock();
+			return cpustat[usage];
+		}
+
+		err = kcpustat_field_vtime(cpustat, curr, usage, cpu, &val);
+		rcu_read_unlock();
+
+		if (!err)
+			return val;
+
+		cpu_relax();
+	}
+}
+EXPORT_SYMBOL_GPL(kcpustat_field);
+
+static int kcpustat_cpu_fetch_vtime(struct kernel_cpustat *dst,
+				    const struct kernel_cpustat *src,
+				    struct task_struct *tsk, int cpu)
+{
+	struct vtime *vtime = &tsk->vtime;
+	unsigned int seq;
+
+	do {
+		u64 *cpustat;
+		u64 delta;
+		int state;
+
+		seq = read_seqcount_begin(&vtime->seqcount);
+
+		state = vtime_state_fetch(vtime, cpu);
+		if (state < 0)
+			return state;
+
+		*dst = *src;
+		cpustat = dst->cpustat;
+
+		/* Task is sleeping, dead or idle, nothing to add */
+		if (state < VTIME_SYS)
+			continue;
+
+		delta = vtime_delta(vtime);
+
+		/*
+		 * Task runs either in user (including guest) or kernel space,
+		 * add pending nohz time to the right place.
+		 */
+		if (state == VTIME_SYS) {
+			cpustat[CPUTIME_SYSTEM] += vtime->stime + delta;
+		} else if (state == VTIME_USER) {
+			if (task_nice(tsk) > 0)
+				cpustat[CPUTIME_NICE] += vtime->utime + delta;
+			else
+				cpustat[CPUTIME_USER] += vtime->utime + delta;
+		} else {
+			WARN_ON_ONCE(state != VTIME_GUEST);
+			if (task_nice(tsk) > 0) {
+				cpustat[CPUTIME_GUEST_NICE] += vtime->gtime + delta;
+				cpustat[CPUTIME_NICE] += vtime->gtime + delta;
+			} else {
+				cpustat[CPUTIME_GUEST] += vtime->gtime + delta;
+				cpustat[CPUTIME_USER] += vtime->gtime + delta;
+			}
+		}
+	} while (read_seqcount_retry(&vtime->seqcount, seq));
+
+	return 0;
+}
+
+void kcpustat_cpu_fetch(struct kernel_cpustat *dst, int cpu)
+{
+	const struct kernel_cpustat *src = &kcpustat_cpu(cpu);
+	struct rq *rq;
+	int err;
+
+	if (!vtime_accounting_enabled_cpu(cpu)) {
+		*dst = *src;
+		return;
+	}
+
+	rq = cpu_rq(cpu);
+
+	for (;;) {
+		struct task_struct *curr;
+
+		rcu_read_lock();
+		curr = rcu_dereference(rq->curr);
+		if (WARN_ON_ONCE(!curr)) {
+			rcu_read_unlock();
+			*dst = *src;
+			return;
+		}
+
+		err = kcpustat_cpu_fetch_vtime(dst, src, curr, cpu);
+		rcu_read_unlock();
+
+		if (!err)
+			return;
+
+		cpu_relax();
+	}
+}
+EXPORT_SYMBOL_GPL(kcpustat_cpu_fetch);
+
+#endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
new file mode 100644
index 0000000000..d78f2e8769
--- /dev/null
+++ b/kernel/sched/deadline.c
@@ -0,0 +1,3113 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Deadline Scheduling Class (SCHED_DEADLINE)
+ *
+ * Earliest Deadline First (EDF) + Constant Bandwidth Server (CBS).
+ *
+ * Tasks that periodically executes their instances for less than their
+ * runtime won't miss any of their deadlines.
+ * Tasks that are not periodic or sporadic or that tries to execute more
+ * than their reserved bandwidth will be slowed down (and may potentially
+ * miss some of their deadlines), and won't affect any other task.
+ *
+ * Copyright (C) 2012 Dario Faggioli <raistlin@linux.it>,
+ *                    Juri Lelli <juri.lelli@gmail.com>,
+ *                    Michael Trimarchi <michael@amarulasolutions.com>,
+ *                    Fabio Checconi <fchecconi@gmail.com>
+ */
+
+#include <linux/cpuset.h>
+
+/*
+ * Default limits for DL period; on the top end we guard against small util
+ * tasks still getting ridiculously long effective runtimes, on the bottom end we
+ * guard against timer DoS.
+ */
+static unsigned int sysctl_sched_dl_period_max = 1 << 22; /* ~4 seconds */
+static unsigned int sysctl_sched_dl_period_min = 100;     /* 100 us */
+#ifdef CONFIG_SYSCTL
+static struct ctl_table sched_dl_sysctls[] = {
+	{
+		.procname       = "sched_deadline_period_max_us",
+		.data           = &sysctl_sched_dl_period_max,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = proc_douintvec_minmax,
+		.extra1         = (void *)&sysctl_sched_dl_period_min,
+	},
+	{
+		.procname       = "sched_deadline_period_min_us",
+		.data           = &sysctl_sched_dl_period_min,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = proc_douintvec_minmax,
+		.extra2         = (void *)&sysctl_sched_dl_period_max,
+	},
+	{}
+};
+
+static int __init sched_dl_sysctl_init(void)
+{
+	register_sysctl_init("kernel", sched_dl_sysctls);
+	return 0;
+}
+late_initcall(sched_dl_sysctl_init);
+#endif
+
+static inline struct task_struct *dl_task_of(struct sched_dl_entity *dl_se)
+{
+	return container_of(dl_se, struct task_struct, dl);
+}
+
+static inline struct rq *rq_of_dl_rq(struct dl_rq *dl_rq)
+{
+	return container_of(dl_rq, struct rq, dl);
+}
+
+static inline struct dl_rq *dl_rq_of_se(struct sched_dl_entity *dl_se)
+{
+	struct task_struct *p = dl_task_of(dl_se);
+	struct rq *rq = task_rq(p);
+
+	return &rq->dl;
+}
+
+static inline int on_dl_rq(struct sched_dl_entity *dl_se)
+{
+	return !RB_EMPTY_NODE(&dl_se->rb_node);
+}
+
+#ifdef CONFIG_RT_MUTEXES
+static inline struct sched_dl_entity *pi_of(struct sched_dl_entity *dl_se)
+{
+	return dl_se->pi_se;
+}
+
+static inline bool is_dl_boosted(struct sched_dl_entity *dl_se)
+{
+	return pi_of(dl_se) != dl_se;
+}
+#else
+static inline struct sched_dl_entity *pi_of(struct sched_dl_entity *dl_se)
+{
+	return dl_se;
+}
+
+static inline bool is_dl_boosted(struct sched_dl_entity *dl_se)
+{
+	return false;
+}
+#endif
+
+#ifdef CONFIG_SMP
+static inline struct dl_bw *dl_bw_of(int i)
+{
+	RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(),
+			 "sched RCU must be held");
+	return &cpu_rq(i)->rd->dl_bw;
+}
+
+static inline int dl_bw_cpus(int i)
+{
+	struct root_domain *rd = cpu_rq(i)->rd;
+	int cpus;
+
+	RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(),
+			 "sched RCU must be held");
+
+	if (cpumask_subset(rd->span, cpu_active_mask))
+		return cpumask_weight(rd->span);
+
+	cpus = 0;
+
+	for_each_cpu_and(i, rd->span, cpu_active_mask)
+		cpus++;
+
+	return cpus;
+}
+
+static inline unsigned long __dl_bw_capacity(const struct cpumask *mask)
+{
+	unsigned long cap = 0;
+	int i;
+
+	for_each_cpu_and(i, mask, cpu_active_mask)
+		cap += capacity_orig_of(i);
+
+	return cap;
+}
+
+/*
+ * XXX Fix: If 'rq->rd == def_root_domain' perform AC against capacity
+ * of the CPU the task is running on rather rd's \Sum CPU capacity.
+ */
+static inline unsigned long dl_bw_capacity(int i)
+{
+	if (!sched_asym_cpucap_active() &&
+	    capacity_orig_of(i) == SCHED_CAPACITY_SCALE) {
+		return dl_bw_cpus(i) << SCHED_CAPACITY_SHIFT;
+	} else {
+		RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(),
+				 "sched RCU must be held");
+
+		return __dl_bw_capacity(cpu_rq(i)->rd->span);
+	}
+}
+
+static inline bool dl_bw_visited(int cpu, u64 gen)
+{
+	struct root_domain *rd = cpu_rq(cpu)->rd;
+
+	if (rd->visit_gen == gen)
+		return true;
+
+	rd->visit_gen = gen;
+	return false;
+}
+
+static inline
+void __dl_update(struct dl_bw *dl_b, s64 bw)
+{
+	struct root_domain *rd = container_of(dl_b, struct root_domain, dl_bw);
+	int i;
+
+	RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(),
+			 "sched RCU must be held");
+	for_each_cpu_and(i, rd->span, cpu_active_mask) {
+		struct rq *rq = cpu_rq(i);
+
+		rq->dl.extra_bw += bw;
+	}
+}
+#else
+static inline struct dl_bw *dl_bw_of(int i)
+{
+	return &cpu_rq(i)->dl.dl_bw;
+}
+
+static inline int dl_bw_cpus(int i)
+{
+	return 1;
+}
+
+static inline unsigned long dl_bw_capacity(int i)
+{
+	return SCHED_CAPACITY_SCALE;
+}
+
+static inline bool dl_bw_visited(int cpu, u64 gen)
+{
+	return false;
+}
+
+static inline
+void __dl_update(struct dl_bw *dl_b, s64 bw)
+{
+	struct dl_rq *dl = container_of(dl_b, struct dl_rq, dl_bw);
+
+	dl->extra_bw += bw;
+}
+#endif
+
+static inline
+void __dl_sub(struct dl_bw *dl_b, u64 tsk_bw, int cpus)
+{
+	dl_b->total_bw -= tsk_bw;
+	__dl_update(dl_b, (s32)tsk_bw / cpus);
+}
+
+static inline
+void __dl_add(struct dl_bw *dl_b, u64 tsk_bw, int cpus)
+{
+	dl_b->total_bw += tsk_bw;
+	__dl_update(dl_b, -((s32)tsk_bw / cpus));
+}
+
+static inline bool
+__dl_overflow(struct dl_bw *dl_b, unsigned long cap, u64 old_bw, u64 new_bw)
+{
+	return dl_b->bw != -1 &&
+	       cap_scale(dl_b->bw, cap) < dl_b->total_bw - old_bw + new_bw;
+}
+
+static inline
+void __add_running_bw(u64 dl_bw, struct dl_rq *dl_rq)
+{
+	u64 old = dl_rq->running_bw;
+
+	lockdep_assert_rq_held(rq_of_dl_rq(dl_rq));
+	dl_rq->running_bw += dl_bw;
+	SCHED_WARN_ON(dl_rq->running_bw < old); /* overflow */
+	SCHED_WARN_ON(dl_rq->running_bw > dl_rq->this_bw);
+	/* kick cpufreq (see the comment in kernel/sched/sched.h). */
+	cpufreq_update_util(rq_of_dl_rq(dl_rq), 0);
+}
+
+static inline
+void __sub_running_bw(u64 dl_bw, struct dl_rq *dl_rq)
+{
+	u64 old = dl_rq->running_bw;
+
+	lockdep_assert_rq_held(rq_of_dl_rq(dl_rq));
+	dl_rq->running_bw -= dl_bw;
+	SCHED_WARN_ON(dl_rq->running_bw > old); /* underflow */
+	if (dl_rq->running_bw > old)
+		dl_rq->running_bw = 0;
+	/* kick cpufreq (see the comment in kernel/sched/sched.h). */
+	cpufreq_update_util(rq_of_dl_rq(dl_rq), 0);
+}
+
+static inline
+void __add_rq_bw(u64 dl_bw, struct dl_rq *dl_rq)
+{
+	u64 old = dl_rq->this_bw;
+
+	lockdep_assert_rq_held(rq_of_dl_rq(dl_rq));
+	dl_rq->this_bw += dl_bw;
+	SCHED_WARN_ON(dl_rq->this_bw < old); /* overflow */
+}
+
+static inline
+void __sub_rq_bw(u64 dl_bw, struct dl_rq *dl_rq)
+{
+	u64 old = dl_rq->this_bw;
+
+	lockdep_assert_rq_held(rq_of_dl_rq(dl_rq));
+	dl_rq->this_bw -= dl_bw;
+	SCHED_WARN_ON(dl_rq->this_bw > old); /* underflow */
+	if (dl_rq->this_bw > old)
+		dl_rq->this_bw = 0;
+	SCHED_WARN_ON(dl_rq->running_bw > dl_rq->this_bw);
+}
+
+static inline
+void add_rq_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+	if (!dl_entity_is_special(dl_se))
+		__add_rq_bw(dl_se->dl_bw, dl_rq);
+}
+
+static inline
+void sub_rq_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+	if (!dl_entity_is_special(dl_se))
+		__sub_rq_bw(dl_se->dl_bw, dl_rq);
+}
+
+static inline
+void add_running_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+	if (!dl_entity_is_special(dl_se))
+		__add_running_bw(dl_se->dl_bw, dl_rq);
+}
+
+static inline
+void sub_running_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+	if (!dl_entity_is_special(dl_se))
+		__sub_running_bw(dl_se->dl_bw, dl_rq);
+}
+
+static void dl_change_utilization(struct task_struct *p, u64 new_bw)
+{
+	struct rq *rq;
+
+	WARN_ON_ONCE(p->dl.flags & SCHED_FLAG_SUGOV);
+
+	if (task_on_rq_queued(p))
+		return;
+
+	rq = task_rq(p);
+	if (p->dl.dl_non_contending) {
+		sub_running_bw(&p->dl, &rq->dl);
+		p->dl.dl_non_contending = 0;
+		/*
+		 * If the timer handler is currently running and the
+		 * timer cannot be canceled, inactive_task_timer()
+		 * will see that dl_not_contending is not set, and
+		 * will not touch the rq's active utilization,
+		 * so we are still safe.
+		 */
+		if (hrtimer_try_to_cancel(&p->dl.inactive_timer) == 1)
+			put_task_struct(p);
+	}
+	__sub_rq_bw(p->dl.dl_bw, &rq->dl);
+	__add_rq_bw(new_bw, &rq->dl);
+}
+
+/*
+ * The utilization of a task cannot be immediately removed from
+ * the rq active utilization (running_bw) when the task blocks.
+ * Instead, we have to wait for the so called "0-lag time".
+ *
+ * If a task blocks before the "0-lag time", a timer (the inactive
+ * timer) is armed, and running_bw is decreased when the timer
+ * fires.
+ *
+ * If the task wakes up again before the inactive timer fires,
+ * the timer is canceled, whereas if the task wakes up after the
+ * inactive timer fired (and running_bw has been decreased) the
+ * task's utilization has to be added to running_bw again.
+ * A flag in the deadline scheduling entity (dl_non_contending)
+ * is used to avoid race conditions between the inactive timer handler
+ * and task wakeups.
+ *
+ * The following diagram shows how running_bw is updated. A task is
+ * "ACTIVE" when its utilization contributes to running_bw; an
+ * "ACTIVE contending" task is in the TASK_RUNNING state, while an
+ * "ACTIVE non contending" task is a blocked task for which the "0-lag time"
+ * has not passed yet. An "INACTIVE" task is a task for which the "0-lag"
+ * time already passed, which does not contribute to running_bw anymore.
+ *                              +------------------+
+ *             wakeup           |    ACTIVE        |
+ *          +------------------>+   contending     |
+ *          | add_running_bw    |                  |
+ *          |                   +----+------+------+
+ *          |                        |      ^
+ *          |                dequeue |      |
+ * +--------+-------+                |      |
+ * |                |   t >= 0-lag   |      | wakeup
+ * |    INACTIVE    |<---------------+      |
+ * |                | sub_running_bw |      |
+ * +--------+-------+                |      |
+ *          ^                        |      |
+ *          |              t < 0-lag |      |
+ *          |                        |      |
+ *          |                        V      |
+ *          |                   +----+------+------+
+ *          | sub_running_bw    |    ACTIVE        |
+ *          +-------------------+                  |
+ *            inactive timer    |  non contending  |
+ *            fired             +------------------+
+ *
+ * The task_non_contending() function is invoked when a task
+ * blocks, and checks if the 0-lag time already passed or
+ * not (in the first case, it directly updates running_bw;
+ * in the second case, it arms the inactive timer).
+ *
+ * The task_contending() function is invoked when a task wakes
+ * up, and checks if the task is still in the "ACTIVE non contending"
+ * state or not (in the second case, it updates running_bw).
+ */
+static void task_non_contending(struct task_struct *p)
+{
+	struct sched_dl_entity *dl_se = &p->dl;
+	struct hrtimer *timer = &dl_se->inactive_timer;
+	struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
+	struct rq *rq = rq_of_dl_rq(dl_rq);
+	s64 zerolag_time;
+
+	/*
+	 * If this is a non-deadline task that has been boosted,
+	 * do nothing
+	 */
+	if (dl_se->dl_runtime == 0)
+		return;
+
+	if (dl_entity_is_special(dl_se))
+		return;
+
+	WARN_ON(dl_se->dl_non_contending);
+
+	zerolag_time = dl_se->deadline -
+		 div64_long((dl_se->runtime * dl_se->dl_period),
+			dl_se->dl_runtime);
+
+	/*
+	 * Using relative times instead of the absolute "0-lag time"
+	 * allows to simplify the code
+	 */
+	zerolag_time -= rq_clock(rq);
+
+	/*
+	 * If the "0-lag time" already passed, decrease the active
+	 * utilization now, instead of starting a timer
+	 */
+	if ((zerolag_time < 0) || hrtimer_active(&dl_se->inactive_timer)) {
+		if (dl_task(p))
+			sub_running_bw(dl_se, dl_rq);
+		if (!dl_task(p) || READ_ONCE(p->__state) == TASK_DEAD) {
+			struct dl_bw *dl_b = dl_bw_of(task_cpu(p));
+
+			if (READ_ONCE(p->__state) == TASK_DEAD)
+				sub_rq_bw(&p->dl, &rq->dl);
+			raw_spin_lock(&dl_b->lock);
+			__dl_sub(dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p)));
+			raw_spin_unlock(&dl_b->lock);
+			__dl_clear_params(p);
+		}
+
+		return;
+	}
+
+	dl_se->dl_non_contending = 1;
+	get_task_struct(p);
+	hrtimer_start(timer, ns_to_ktime(zerolag_time), HRTIMER_MODE_REL_HARD);
+}
+
+static void task_contending(struct sched_dl_entity *dl_se, int flags)
+{
+	struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
+
+	/*
+	 * If this is a non-deadline task that has been boosted,
+	 * do nothing
+	 */
+	if (dl_se->dl_runtime == 0)
+		return;
+
+	if (flags & ENQUEUE_MIGRATED)
+		add_rq_bw(dl_se, dl_rq);
+
+	if (dl_se->dl_non_contending) {
+		dl_se->dl_non_contending = 0;
+		/*
+		 * If the timer handler is currently running and the
+		 * timer cannot be canceled, inactive_task_timer()
+		 * will see that dl_not_contending is not set, and
+		 * will not touch the rq's active utilization,
+		 * so we are still safe.
+		 */
+		if (hrtimer_try_to_cancel(&dl_se->inactive_timer) == 1)
+			put_task_struct(dl_task_of(dl_se));
+	} else {
+		/*
+		 * Since "dl_non_contending" is not set, the
+		 * task's utilization has already been removed from
+		 * active utilization (either when the task blocked,
+		 * when the "inactive timer" fired).
+		 * So, add it back.
+		 */
+		add_running_bw(dl_se, dl_rq);
+	}
+}
+
+static inline int is_leftmost(struct task_struct *p, struct dl_rq *dl_rq)
+{
+	struct sched_dl_entity *dl_se = &p->dl;
+
+	return rb_first_cached(&dl_rq->root) == &dl_se->rb_node;
+}
+
+static void init_dl_rq_bw_ratio(struct dl_rq *dl_rq);
+
+void init_dl_bw(struct dl_bw *dl_b)
+{
+	raw_spin_lock_init(&dl_b->lock);
+	if (global_rt_runtime() == RUNTIME_INF)
+		dl_b->bw = -1;
+	else
+		dl_b->bw = to_ratio(global_rt_period(), global_rt_runtime());
+	dl_b->total_bw = 0;
+}
+
+void init_dl_rq(struct dl_rq *dl_rq)
+{
+	dl_rq->root = RB_ROOT_CACHED;
+
+#ifdef CONFIG_SMP
+	/* zero means no -deadline tasks */
+	dl_rq->earliest_dl.curr = dl_rq->earliest_dl.next = 0;
+
+	dl_rq->dl_nr_migratory = 0;
+	dl_rq->overloaded = 0;
+	dl_rq->pushable_dl_tasks_root = RB_ROOT_CACHED;
+#else
+	init_dl_bw(&dl_rq->dl_bw);
+#endif
+
+	dl_rq->running_bw = 0;
+	dl_rq->this_bw = 0;
+	init_dl_rq_bw_ratio(dl_rq);
+}
+
+#ifdef CONFIG_SMP
+
+static inline int dl_overloaded(struct rq *rq)
+{
+	return atomic_read(&rq->rd->dlo_count);
+}
+
+static inline void dl_set_overload(struct rq *rq)
+{
+	if (!rq->online)
+		return;
+
+	cpumask_set_cpu(rq->cpu, rq->rd->dlo_mask);
+	/*
+	 * Must be visible before the overload count is
+	 * set (as in sched_rt.c).
+	 *
+	 * Matched by the barrier in pull_dl_task().
+	 */
+	smp_wmb();
+	atomic_inc(&rq->rd->dlo_count);
+}
+
+static inline void dl_clear_overload(struct rq *rq)
+{
+	if (!rq->online)
+		return;
+
+	atomic_dec(&rq->rd->dlo_count);
+	cpumask_clear_cpu(rq->cpu, rq->rd->dlo_mask);
+}
+
+static void update_dl_migration(struct dl_rq *dl_rq)
+{
+	if (dl_rq->dl_nr_migratory && dl_rq->dl_nr_running > 1) {
+		if (!dl_rq->overloaded) {
+			dl_set_overload(rq_of_dl_rq(dl_rq));
+			dl_rq->overloaded = 1;
+		}
+	} else if (dl_rq->overloaded) {
+		dl_clear_overload(rq_of_dl_rq(dl_rq));
+		dl_rq->overloaded = 0;
+	}
+}
+
+static void inc_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+	struct task_struct *p = dl_task_of(dl_se);
+
+	if (p->nr_cpus_allowed > 1)
+		dl_rq->dl_nr_migratory++;
+
+	update_dl_migration(dl_rq);
+}
+
+static void dec_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+	struct task_struct *p = dl_task_of(dl_se);
+
+	if (p->nr_cpus_allowed > 1)
+		dl_rq->dl_nr_migratory--;
+
+	update_dl_migration(dl_rq);
+}
+
+#define __node_2_pdl(node) \
+	rb_entry((node), struct task_struct, pushable_dl_tasks)
+
+static inline bool __pushable_less(struct rb_node *a, const struct rb_node *b)
+{
+	return dl_entity_preempt(&__node_2_pdl(a)->dl, &__node_2_pdl(b)->dl);
+}
+
+/*
+ * The list of pushable -deadline task is not a plist, like in
+ * sched_rt.c, it is an rb-tree with tasks ordered by deadline.
+ */
+static void enqueue_pushable_dl_task(struct rq *rq, struct task_struct *p)
+{
+	struct rb_node *leftmost;
+
+	WARN_ON_ONCE(!RB_EMPTY_NODE(&p->pushable_dl_tasks));
+
+	leftmost = rb_add_cached(&p->pushable_dl_tasks,
+				 &rq->dl.pushable_dl_tasks_root,
+				 __pushable_less);
+	if (leftmost)
+		rq->dl.earliest_dl.next = p->dl.deadline;
+}
+
+static void dequeue_pushable_dl_task(struct rq *rq, struct task_struct *p)
+{
+	struct dl_rq *dl_rq = &rq->dl;
+	struct rb_root_cached *root = &dl_rq->pushable_dl_tasks_root;
+	struct rb_node *leftmost;
+
+	if (RB_EMPTY_NODE(&p->pushable_dl_tasks))
+		return;
+
+	leftmost = rb_erase_cached(&p->pushable_dl_tasks, root);
+	if (leftmost)
+		dl_rq->earliest_dl.next = __node_2_pdl(leftmost)->dl.deadline;
+
+	RB_CLEAR_NODE(&p->pushable_dl_tasks);
+}
+
+static inline int has_pushable_dl_tasks(struct rq *rq)
+{
+	return !RB_EMPTY_ROOT(&rq->dl.pushable_dl_tasks_root.rb_root);
+}
+
+static int push_dl_task(struct rq *rq);
+
+static inline bool need_pull_dl_task(struct rq *rq, struct task_struct *prev)
+{
+	return rq->online && dl_task(prev);
+}
+
+static DEFINE_PER_CPU(struct balance_callback, dl_push_head);
+static DEFINE_PER_CPU(struct balance_callback, dl_pull_head);
+
+static void push_dl_tasks(struct rq *);
+static void pull_dl_task(struct rq *);
+
+static inline void deadline_queue_push_tasks(struct rq *rq)
+{
+	if (!has_pushable_dl_tasks(rq))
+		return;
+
+	queue_balance_callback(rq, &per_cpu(dl_push_head, rq->cpu), push_dl_tasks);
+}
+
+static inline void deadline_queue_pull_task(struct rq *rq)
+{
+	queue_balance_callback(rq, &per_cpu(dl_pull_head, rq->cpu), pull_dl_task);
+}
+
+static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq);
+
+static struct rq *dl_task_offline_migration(struct rq *rq, struct task_struct *p)
+{
+	struct rq *later_rq = NULL;
+	struct dl_bw *dl_b;
+
+	later_rq = find_lock_later_rq(p, rq);
+	if (!later_rq) {
+		int cpu;
+
+		/*
+		 * If we cannot preempt any rq, fall back to pick any
+		 * online CPU:
+		 */
+		cpu = cpumask_any_and(cpu_active_mask, p->cpus_ptr);
+		if (cpu >= nr_cpu_ids) {
+			/*
+			 * Failed to find any suitable CPU.
+			 * The task will never come back!
+			 */
+			WARN_ON_ONCE(dl_bandwidth_enabled());
+
+			/*
+			 * If admission control is disabled we
+			 * try a little harder to let the task
+			 * run.
+			 */
+			cpu = cpumask_any(cpu_active_mask);
+		}
+		later_rq = cpu_rq(cpu);
+		double_lock_balance(rq, later_rq);
+	}
+
+	if (p->dl.dl_non_contending || p->dl.dl_throttled) {
+		/*
+		 * Inactive timer is armed (or callback is running, but
+		 * waiting for us to release rq locks). In any case, when it
+		 * will fire (or continue), it will see running_bw of this
+		 * task migrated to later_rq (and correctly handle it).
+		 */
+		sub_running_bw(&p->dl, &rq->dl);
+		sub_rq_bw(&p->dl, &rq->dl);
+
+		add_rq_bw(&p->dl, &later_rq->dl);
+		add_running_bw(&p->dl, &later_rq->dl);
+	} else {
+		sub_rq_bw(&p->dl, &rq->dl);
+		add_rq_bw(&p->dl, &later_rq->dl);
+	}
+
+	/*
+	 * And we finally need to fixup root_domain(s) bandwidth accounting,
+	 * since p is still hanging out in the old (now moved to default) root
+	 * domain.
+	 */
+	dl_b = &rq->rd->dl_bw;
+	raw_spin_lock(&dl_b->lock);
+	__dl_sub(dl_b, p->dl.dl_bw, cpumask_weight(rq->rd->span));
+	raw_spin_unlock(&dl_b->lock);
+
+	dl_b = &later_rq->rd->dl_bw;
+	raw_spin_lock(&dl_b->lock);
+	__dl_add(dl_b, p->dl.dl_bw, cpumask_weight(later_rq->rd->span));
+	raw_spin_unlock(&dl_b->lock);
+
+	set_task_cpu(p, later_rq->cpu);
+	double_unlock_balance(later_rq, rq);
+
+	return later_rq;
+}
+
+#else
+
+static inline
+void enqueue_pushable_dl_task(struct rq *rq, struct task_struct *p)
+{
+}
+
+static inline
+void dequeue_pushable_dl_task(struct rq *rq, struct task_struct *p)
+{
+}
+
+static inline
+void inc_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+}
+
+static inline
+void dec_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+}
+
+static inline void deadline_queue_push_tasks(struct rq *rq)
+{
+}
+
+static inline void deadline_queue_pull_task(struct rq *rq)
+{
+}
+#endif /* CONFIG_SMP */
+
+static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags);
+static void __dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags);
+static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p, int flags);
+
+static inline void replenish_dl_new_period(struct sched_dl_entity *dl_se,
+					    struct rq *rq)
+{
+	/* for non-boosted task, pi_of(dl_se) == dl_se */
+	dl_se->deadline = rq_clock(rq) + pi_of(dl_se)->dl_deadline;
+	dl_se->runtime = pi_of(dl_se)->dl_runtime;
+}
+
+/*
+ * We are being explicitly informed that a new instance is starting,
+ * and this means that:
+ *  - the absolute deadline of the entity has to be placed at
+ *    current time + relative deadline;
+ *  - the runtime of the entity has to be set to the maximum value.
+ *
+ * The capability of specifying such event is useful whenever a -deadline
+ * entity wants to (try to!) synchronize its behaviour with the scheduler's
+ * one, and to (try to!) reconcile itself with its own scheduling
+ * parameters.
+ */
+static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se)
+{
+	struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
+	struct rq *rq = rq_of_dl_rq(dl_rq);
+
+	WARN_ON(is_dl_boosted(dl_se));
+	WARN_ON(dl_time_before(rq_clock(rq), dl_se->deadline));
+
+	/*
+	 * We are racing with the deadline timer. So, do nothing because
+	 * the deadline timer handler will take care of properly recharging
+	 * the runtime and postponing the deadline
+	 */
+	if (dl_se->dl_throttled)
+		return;
+
+	/*
+	 * We use the regular wall clock time to set deadlines in the
+	 * future; in fact, we must consider execution overheads (time
+	 * spent on hardirq context, etc.).
+	 */
+	replenish_dl_new_period(dl_se, rq);
+}
+
+/*
+ * Pure Earliest Deadline First (EDF) scheduling does not deal with the
+ * possibility of a entity lasting more than what it declared, and thus
+ * exhausting its runtime.
+ *
+ * Here we are interested in making runtime overrun possible, but we do
+ * not want a entity which is misbehaving to affect the scheduling of all
+ * other entities.
+ * Therefore, a budgeting strategy called Constant Bandwidth Server (CBS)
+ * is used, in order to confine each entity within its own bandwidth.
+ *
+ * This function deals exactly with that, and ensures that when the runtime
+ * of a entity is replenished, its deadline is also postponed. That ensures
+ * the overrunning entity can't interfere with other entity in the system and
+ * can't make them miss their deadlines. Reasons why this kind of overruns
+ * could happen are, typically, a entity voluntarily trying to overcome its
+ * runtime, or it just underestimated it during sched_setattr().
+ */
+static void replenish_dl_entity(struct sched_dl_entity *dl_se)
+{
+	struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
+	struct rq *rq = rq_of_dl_rq(dl_rq);
+
+	WARN_ON_ONCE(pi_of(dl_se)->dl_runtime <= 0);
+
+	/*
+	 * This could be the case for a !-dl task that is boosted.
+	 * Just go with full inherited parameters.
+	 */
+	if (dl_se->dl_deadline == 0)
+		replenish_dl_new_period(dl_se, rq);
+
+	if (dl_se->dl_yielded && dl_se->runtime > 0)
+		dl_se->runtime = 0;
+
+	/*
+	 * We keep moving the deadline away until we get some
+	 * available runtime for the entity. This ensures correct
+	 * handling of situations where the runtime overrun is
+	 * arbitrary large.
+	 */
+	while (dl_se->runtime <= 0) {
+		dl_se->deadline += pi_of(dl_se)->dl_period;
+		dl_se->runtime += pi_of(dl_se)->dl_runtime;
+	}
+
+	/*
+	 * At this point, the deadline really should be "in
+	 * the future" with respect to rq->clock. If it's
+	 * not, we are, for some reason, lagging too much!
+	 * Anyway, after having warn userspace abut that,
+	 * we still try to keep the things running by
+	 * resetting the deadline and the budget of the
+	 * entity.
+	 */
+	if (dl_time_before(dl_se->deadline, rq_clock(rq))) {
+		printk_deferred_once("sched: DL replenish lagged too much\n");
+		replenish_dl_new_period(dl_se, rq);
+	}
+
+	if (dl_se->dl_yielded)
+		dl_se->dl_yielded = 0;
+	if (dl_se->dl_throttled)
+		dl_se->dl_throttled = 0;
+}
+
+/*
+ * Here we check if --at time t-- an entity (which is probably being
+ * [re]activated or, in general, enqueued) can use its remaining runtime
+ * and its current deadline _without_ exceeding the bandwidth it is
+ * assigned (function returns true if it can't). We are in fact applying
+ * one of the CBS rules: when a task wakes up, if the residual runtime
+ * over residual deadline fits within the allocated bandwidth, then we
+ * can keep the current (absolute) deadline and residual budget without
+ * disrupting the schedulability of the system. Otherwise, we should
+ * refill the runtime and set the deadline a period in the future,
+ * because keeping the current (absolute) deadline of the task would
+ * result in breaking guarantees promised to other tasks (refer to
+ * Documentation/scheduler/sched-deadline.rst for more information).
+ *
+ * This function returns true if:
+ *
+ *   runtime / (deadline - t) > dl_runtime / dl_deadline ,
+ *
+ * IOW we can't recycle current parameters.
+ *
+ * Notice that the bandwidth check is done against the deadline. For
+ * task with deadline equal to period this is the same of using
+ * dl_period instead of dl_deadline in the equation above.
+ */
+static bool dl_entity_overflow(struct sched_dl_entity *dl_se, u64 t)
+{
+	u64 left, right;
+
+	/*
+	 * left and right are the two sides of the equation above,
+	 * after a bit of shuffling to use multiplications instead
+	 * of divisions.
+	 *
+	 * Note that none of the time values involved in the two
+	 * multiplications are absolute: dl_deadline and dl_runtime
+	 * are the relative deadline and the maximum runtime of each
+	 * instance, runtime is the runtime left for the last instance
+	 * and (deadline - t), since t is rq->clock, is the time left
+	 * to the (absolute) deadline. Even if overflowing the u64 type
+	 * is very unlikely to occur in both cases, here we scale down
+	 * as we want to avoid that risk at all. Scaling down by 10
+	 * means that we reduce granularity to 1us. We are fine with it,
+	 * since this is only a true/false check and, anyway, thinking
+	 * of anything below microseconds resolution is actually fiction
+	 * (but still we want to give the user that illusion >;).
+	 */
+	left = (pi_of(dl_se)->dl_deadline >> DL_SCALE) * (dl_se->runtime >> DL_SCALE);
+	right = ((dl_se->deadline - t) >> DL_SCALE) *
+		(pi_of(dl_se)->dl_runtime >> DL_SCALE);
+
+	return dl_time_before(right, left);
+}
+
+/*
+ * Revised wakeup rule [1]: For self-suspending tasks, rather then
+ * re-initializing task's runtime and deadline, the revised wakeup
+ * rule adjusts the task's runtime to avoid the task to overrun its
+ * density.
+ *
+ * Reasoning: a task may overrun the density if:
+ *    runtime / (deadline - t) > dl_runtime / dl_deadline
+ *
+ * Therefore, runtime can be adjusted to:
+ *     runtime = (dl_runtime / dl_deadline) * (deadline - t)
+ *
+ * In such way that runtime will be equal to the maximum density
+ * the task can use without breaking any rule.
+ *
+ * [1] Luca Abeni, Giuseppe Lipari, and Juri Lelli. 2015. Constant
+ * bandwidth server revisited. SIGBED Rev. 11, 4 (January 2015), 19-24.
+ */
+static void
+update_dl_revised_wakeup(struct sched_dl_entity *dl_se, struct rq *rq)
+{
+	u64 laxity = dl_se->deadline - rq_clock(rq);
+
+	/*
+	 * If the task has deadline < period, and the deadline is in the past,
+	 * it should already be throttled before this check.
+	 *
+	 * See update_dl_entity() comments for further details.
+	 */
+	WARN_ON(dl_time_before(dl_se->deadline, rq_clock(rq)));
+
+	dl_se->runtime = (dl_se->dl_density * laxity) >> BW_SHIFT;
+}
+
+/*
+ * Regarding the deadline, a task with implicit deadline has a relative
+ * deadline == relative period. A task with constrained deadline has a
+ * relative deadline <= relative period.
+ *
+ * We support constrained deadline tasks. However, there are some restrictions
+ * applied only for tasks which do not have an implicit deadline. See
+ * update_dl_entity() to know more about such restrictions.
+ *
+ * The dl_is_implicit() returns true if the task has an implicit deadline.
+ */
+static inline bool dl_is_implicit(struct sched_dl_entity *dl_se)
+{
+	return dl_se->dl_deadline == dl_se->dl_period;
+}
+
+/*
+ * When a deadline entity is placed in the runqueue, its runtime and deadline
+ * might need to be updated. This is done by a CBS wake up rule. There are two
+ * different rules: 1) the original CBS; and 2) the Revisited CBS.
+ *
+ * When the task is starting a new period, the Original CBS is used. In this
+ * case, the runtime is replenished and a new absolute deadline is set.
+ *
+ * When a task is queued before the begin of the next period, using the
+ * remaining runtime and deadline could make the entity to overflow, see
+ * dl_entity_overflow() to find more about runtime overflow. When such case
+ * is detected, the runtime and deadline need to be updated.
+ *
+ * If the task has an implicit deadline, i.e., deadline == period, the Original
+ * CBS is applied. the runtime is replenished and a new absolute deadline is
+ * set, as in the previous cases.
+ *
+ * However, the Original CBS does not work properly for tasks with
+ * deadline < period, which are said to have a constrained deadline. By
+ * applying the Original CBS, a constrained deadline task would be able to run
+ * runtime/deadline in a period. With deadline < period, the task would
+ * overrun the runtime/period allowed bandwidth, breaking the admission test.
+ *
+ * In order to prevent this misbehave, the Revisited CBS is used for
+ * constrained deadline tasks when a runtime overflow is detected. In the
+ * Revisited CBS, rather than replenishing & setting a new absolute deadline,
+ * the remaining runtime of the task is reduced to avoid runtime overflow.
+ * Please refer to the comments update_dl_revised_wakeup() function to find
+ * more about the Revised CBS rule.
+ */
+static void update_dl_entity(struct sched_dl_entity *dl_se)
+{
+	struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
+	struct rq *rq = rq_of_dl_rq(dl_rq);
+
+	if (dl_time_before(dl_se->deadline, rq_clock(rq)) ||
+	    dl_entity_overflow(dl_se, rq_clock(rq))) {
+
+		if (unlikely(!dl_is_implicit(dl_se) &&
+			     !dl_time_before(dl_se->deadline, rq_clock(rq)) &&
+			     !is_dl_boosted(dl_se))) {
+			update_dl_revised_wakeup(dl_se, rq);
+			return;
+		}
+
+		replenish_dl_new_period(dl_se, rq);
+	}
+}
+
+static inline u64 dl_next_period(struct sched_dl_entity *dl_se)
+{
+	return dl_se->deadline - dl_se->dl_deadline + dl_se->dl_period;
+}
+
+/*
+ * If the entity depleted all its runtime, and if we want it to sleep
+ * while waiting for some new execution time to become available, we
+ * set the bandwidth replenishment timer to the replenishment instant
+ * and try to activate it.
+ *
+ * Notice that it is important for the caller to know if the timer
+ * actually started or not (i.e., the replenishment instant is in
+ * the future or in the past).
+ */
+static int start_dl_timer(struct task_struct *p)
+{
+	struct sched_dl_entity *dl_se = &p->dl;
+	struct hrtimer *timer = &dl_se->dl_timer;
+	struct rq *rq = task_rq(p);
+	ktime_t now, act;
+	s64 delta;
+
+	lockdep_assert_rq_held(rq);
+
+	/*
+	 * We want the timer to fire at the deadline, but considering
+	 * that it is actually coming from rq->clock and not from
+	 * hrtimer's time base reading.
+	 */
+	act = ns_to_ktime(dl_next_period(dl_se));
+	now = hrtimer_cb_get_time(timer);
+	delta = ktime_to_ns(now) - rq_clock(rq);
+	act = ktime_add_ns(act, delta);
+
+	/*
+	 * If the expiry time already passed, e.g., because the value
+	 * chosen as the deadline is too small, don't even try to
+	 * start the timer in the past!
+	 */
+	if (ktime_us_delta(act, now) < 0)
+		return 0;
+
+	/*
+	 * !enqueued will guarantee another callback; even if one is already in
+	 * progress. This ensures a balanced {get,put}_task_struct().
+	 *
+	 * The race against __run_timer() clearing the enqueued state is
+	 * harmless because we're holding task_rq()->lock, therefore the timer
+	 * expiring after we've done the check will wait on its task_rq_lock()
+	 * and observe our state.
+	 */
+	if (!hrtimer_is_queued(timer)) {
+		get_task_struct(p);
+		hrtimer_start(timer, act, HRTIMER_MODE_ABS_HARD);
+	}
+
+	return 1;
+}
+
+/*
+ * This is the bandwidth enforcement timer callback. If here, we know
+ * a task is not on its dl_rq, since the fact that the timer was running
+ * means the task is throttled and needs a runtime replenishment.
+ *
+ * However, what we actually do depends on the fact the task is active,
+ * (it is on its rq) or has been removed from there by a call to
+ * dequeue_task_dl(). In the former case we must issue the runtime
+ * replenishment and add the task back to the dl_rq; in the latter, we just
+ * do nothing but clearing dl_throttled, so that runtime and deadline
+ * updating (and the queueing back to dl_rq) will be done by the
+ * next call to enqueue_task_dl().
+ */
+static enum hrtimer_restart dl_task_timer(struct hrtimer *timer)
+{
+	struct sched_dl_entity *dl_se = container_of(timer,
+						     struct sched_dl_entity,
+						     dl_timer);
+	struct task_struct *p = dl_task_of(dl_se);
+	struct rq_flags rf;
+	struct rq *rq;
+
+	rq = task_rq_lock(p, &rf);
+
+	/*
+	 * The task might have changed its scheduling policy to something
+	 * different than SCHED_DEADLINE (through switched_from_dl()).
+	 */
+	if (!dl_task(p))
+		goto unlock;
+
+	/*
+	 * The task might have been boosted by someone else and might be in the
+	 * boosting/deboosting path, its not throttled.
+	 */
+	if (is_dl_boosted(dl_se))
+		goto unlock;
+
+	/*
+	 * Spurious timer due to start_dl_timer() race; or we already received
+	 * a replenishment from rt_mutex_setprio().
+	 */
+	if (!dl_se->dl_throttled)
+		goto unlock;
+
+	sched_clock_tick();
+	update_rq_clock(rq);
+
+	/*
+	 * If the throttle happened during sched-out; like:
+	 *
+	 *   schedule()
+	 *     deactivate_task()
+	 *       dequeue_task_dl()
+	 *         update_curr_dl()
+	 *           start_dl_timer()
+	 *         __dequeue_task_dl()
+	 *     prev->on_rq = 0;
+	 *
+	 * We can be both throttled and !queued. Replenish the counter
+	 * but do not enqueue -- wait for our wakeup to do that.
+	 */
+	if (!task_on_rq_queued(p)) {
+		replenish_dl_entity(dl_se);
+		goto unlock;
+	}
+
+#ifdef CONFIG_SMP
+	if (unlikely(!rq->online)) {
+		/*
+		 * If the runqueue is no longer available, migrate the
+		 * task elsewhere. This necessarily changes rq.
+		 */
+		lockdep_unpin_lock(__rq_lockp(rq), rf.cookie);
+		rq = dl_task_offline_migration(rq, p);
+		rf.cookie = lockdep_pin_lock(__rq_lockp(rq));
+		update_rq_clock(rq);
+
+		/*
+		 * Now that the task has been migrated to the new RQ and we
+		 * have that locked, proceed as normal and enqueue the task
+		 * there.
+		 */
+	}
+#endif
+
+	enqueue_task_dl(rq, p, ENQUEUE_REPLENISH);
+	if (dl_task(rq->curr))
+		check_preempt_curr_dl(rq, p, 0);
+	else
+		resched_curr(rq);
+
+#ifdef CONFIG_SMP
+	/*
+	 * Queueing this task back might have overloaded rq, check if we need
+	 * to kick someone away.
+	 */
+	if (has_pushable_dl_tasks(rq)) {
+		/*
+		 * Nothing relies on rq->lock after this, so its safe to drop
+		 * rq->lock.
+		 */
+		rq_unpin_lock(rq, &rf);
+		push_dl_task(rq);
+		rq_repin_lock(rq, &rf);
+	}
+#endif
+
+unlock:
+	task_rq_unlock(rq, p, &rf);
+
+	/*
+	 * This can free the task_struct, including this hrtimer, do not touch
+	 * anything related to that after this.
+	 */
+	put_task_struct(p);
+
+	return HRTIMER_NORESTART;
+}
+
+void init_dl_task_timer(struct sched_dl_entity *dl_se)
+{
+	struct hrtimer *timer = &dl_se->dl_timer;
+
+	hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
+	timer->function = dl_task_timer;
+}
+
+/*
+ * During the activation, CBS checks if it can reuse the current task's
+ * runtime and period. If the deadline of the task is in the past, CBS
+ * cannot use the runtime, and so it replenishes the task. This rule
+ * works fine for implicit deadline tasks (deadline == period), and the
+ * CBS was designed for implicit deadline tasks. However, a task with
+ * constrained deadline (deadline < period) might be awakened after the
+ * deadline, but before the next period. In this case, replenishing the
+ * task would allow it to run for runtime / deadline. As in this case
+ * deadline < period, CBS enables a task to run for more than the
+ * runtime / period. In a very loaded system, this can cause a domino
+ * effect, making other tasks miss their deadlines.
+ *
+ * To avoid this problem, in the activation of a constrained deadline
+ * task after the deadline but before the next period, throttle the
+ * task and set the replenishing timer to the begin of the next period,
+ * unless it is boosted.
+ */
+static inline void dl_check_constrained_dl(struct sched_dl_entity *dl_se)
+{
+	struct task_struct *p = dl_task_of(dl_se);
+	struct rq *rq = rq_of_dl_rq(dl_rq_of_se(dl_se));
+
+	if (dl_time_before(dl_se->deadline, rq_clock(rq)) &&
+	    dl_time_before(rq_clock(rq), dl_next_period(dl_se))) {
+		if (unlikely(is_dl_boosted(dl_se) || !start_dl_timer(p)))
+			return;
+		dl_se->dl_throttled = 1;
+		if (dl_se->runtime > 0)
+			dl_se->runtime = 0;
+	}
+}
+
+static
+int dl_runtime_exceeded(struct sched_dl_entity *dl_se)
+{
+	return (dl_se->runtime <= 0);
+}
+
+/*
+ * This function implements the GRUB accounting rule. According to the
+ * GRUB reclaiming algorithm, the runtime is not decreased as "dq = -dt",
+ * but as "dq = -(max{u, (Umax - Uinact - Uextra)} / Umax) dt",
+ * where u is the utilization of the task, Umax is the maximum reclaimable
+ * utilization, Uinact is the (per-runqueue) inactive utilization, computed
+ * as the difference between the "total runqueue utilization" and the
+ * "runqueue active utilization", and Uextra is the (per runqueue) extra
+ * reclaimable utilization.
+ * Since rq->dl.running_bw and rq->dl.this_bw contain utilizations multiplied
+ * by 2^BW_SHIFT, the result has to be shifted right by BW_SHIFT.
+ * Since rq->dl.bw_ratio contains 1 / Umax multiplied by 2^RATIO_SHIFT, dl_bw
+ * is multiped by rq->dl.bw_ratio and shifted right by RATIO_SHIFT.
+ * Since delta is a 64 bit variable, to have an overflow its value should be
+ * larger than 2^(64 - 20 - 8), which is more than 64 seconds. So, overflow is
+ * not an issue here.
+ */
+static u64 grub_reclaim(u64 delta, struct rq *rq, struct sched_dl_entity *dl_se)
+{
+	u64 u_act;
+	u64 u_inact = rq->dl.this_bw - rq->dl.running_bw; /* Utot - Uact */
+
+	/*
+	 * Instead of computing max{u, (u_max - u_inact - u_extra)}, we
+	 * compare u_inact + u_extra with u_max - u, because u_inact + u_extra
+	 * can be larger than u_max. So, u_max - u_inact - u_extra would be
+	 * negative leading to wrong results.
+	 */
+	if (u_inact + rq->dl.extra_bw > rq->dl.max_bw - dl_se->dl_bw)
+		u_act = dl_se->dl_bw;
+	else
+		u_act = rq->dl.max_bw - u_inact - rq->dl.extra_bw;
+
+	u_act = (u_act * rq->dl.bw_ratio) >> RATIO_SHIFT;
+	return (delta * u_act) >> BW_SHIFT;
+}
+
+/*
+ * Update the current task's runtime statistics (provided it is still
+ * a -deadline task and has not been removed from the dl_rq).
+ */
+static void update_curr_dl(struct rq *rq)
+{
+	struct task_struct *curr = rq->curr;
+	struct sched_dl_entity *dl_se = &curr->dl;
+	u64 delta_exec, scaled_delta_exec;
+	int cpu = cpu_of(rq);
+	u64 now;
+
+	if (!dl_task(curr) || !on_dl_rq(dl_se))
+		return;
+
+	/*
+	 * Consumed budget is computed considering the time as
+	 * observed by schedulable tasks (excluding time spent
+	 * in hardirq context, etc.). Deadlines are instead
+	 * computed using hard walltime. This seems to be the more
+	 * natural solution, but the full ramifications of this
+	 * approach need further study.
+	 */
+	now = rq_clock_task(rq);
+	delta_exec = now - curr->se.exec_start;
+	if (unlikely((s64)delta_exec <= 0)) {
+		if (unlikely(dl_se->dl_yielded))
+			goto throttle;
+		return;
+	}
+
+	schedstat_set(curr->stats.exec_max,
+		      max(curr->stats.exec_max, delta_exec));
+
+	trace_sched_stat_runtime(curr, delta_exec, 0);
+
+	update_current_exec_runtime(curr, now, delta_exec);
+
+	if (dl_entity_is_special(dl_se))
+		return;
+
+	/*
+	 * For tasks that participate in GRUB, we implement GRUB-PA: the
+	 * spare reclaimed bandwidth is used to clock down frequency.
+	 *
+	 * For the others, we still need to scale reservation parameters
+	 * according to current frequency and CPU maximum capacity.
+	 */
+	if (unlikely(dl_se->flags & SCHED_FLAG_RECLAIM)) {
+		scaled_delta_exec = grub_reclaim(delta_exec,
+						 rq,
+						 &curr->dl);
+	} else {
+		unsigned long scale_freq = arch_scale_freq_capacity(cpu);
+		unsigned long scale_cpu = arch_scale_cpu_capacity(cpu);
+
+		scaled_delta_exec = cap_scale(delta_exec, scale_freq);
+		scaled_delta_exec = cap_scale(scaled_delta_exec, scale_cpu);
+	}
+
+	dl_se->runtime -= scaled_delta_exec;
+
+throttle:
+	if (dl_runtime_exceeded(dl_se) || dl_se->dl_yielded) {
+		dl_se->dl_throttled = 1;
+
+		/* If requested, inform the user about runtime overruns. */
+		if (dl_runtime_exceeded(dl_se) &&
+		    (dl_se->flags & SCHED_FLAG_DL_OVERRUN))
+			dl_se->dl_overrun = 1;
+
+		__dequeue_task_dl(rq, curr, 0);
+		if (unlikely(is_dl_boosted(dl_se) || !start_dl_timer(curr)))
+			enqueue_task_dl(rq, curr, ENQUEUE_REPLENISH);
+
+		if (!is_leftmost(curr, &rq->dl))
+			resched_curr(rq);
+	}
+
+	/*
+	 * Because -- for now -- we share the rt bandwidth, we need to
+	 * account our runtime there too, otherwise actual rt tasks
+	 * would be able to exceed the shared quota.
+	 *
+	 * Account to the root rt group for now.
+	 *
+	 * The solution we're working towards is having the RT groups scheduled
+	 * using deadline servers -- however there's a few nasties to figure
+	 * out before that can happen.
+	 */
+	if (rt_bandwidth_enabled()) {
+		struct rt_rq *rt_rq = &rq->rt;
+
+		raw_spin_lock(&rt_rq->rt_runtime_lock);
+		/*
+		 * We'll let actual RT tasks worry about the overflow here, we
+		 * have our own CBS to keep us inline; only account when RT
+		 * bandwidth is relevant.
+		 */
+		if (sched_rt_bandwidth_account(rt_rq))
+			rt_rq->rt_time += delta_exec;
+		raw_spin_unlock(&rt_rq->rt_runtime_lock);
+	}
+}
+
+static enum hrtimer_restart inactive_task_timer(struct hrtimer *timer)
+{
+	struct sched_dl_entity *dl_se = container_of(timer,
+						     struct sched_dl_entity,
+						     inactive_timer);
+	struct task_struct *p = dl_task_of(dl_se);
+	struct rq_flags rf;
+	struct rq *rq;
+
+	rq = task_rq_lock(p, &rf);
+
+	sched_clock_tick();
+	update_rq_clock(rq);
+
+	if (!dl_task(p) || READ_ONCE(p->__state) == TASK_DEAD) {
+		struct dl_bw *dl_b = dl_bw_of(task_cpu(p));
+
+		if (READ_ONCE(p->__state) == TASK_DEAD && dl_se->dl_non_contending) {
+			sub_running_bw(&p->dl, dl_rq_of_se(&p->dl));
+			sub_rq_bw(&p->dl, dl_rq_of_se(&p->dl));
+			dl_se->dl_non_contending = 0;
+		}
+
+		raw_spin_lock(&dl_b->lock);
+		__dl_sub(dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p)));
+		raw_spin_unlock(&dl_b->lock);
+		__dl_clear_params(p);
+
+		goto unlock;
+	}
+	if (dl_se->dl_non_contending == 0)
+		goto unlock;
+
+	sub_running_bw(dl_se, &rq->dl);
+	dl_se->dl_non_contending = 0;
+unlock:
+	task_rq_unlock(rq, p, &rf);
+	put_task_struct(p);
+
+	return HRTIMER_NORESTART;
+}
+
+void init_dl_inactive_task_timer(struct sched_dl_entity *dl_se)
+{
+	struct hrtimer *timer = &dl_se->inactive_timer;
+
+	hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
+	timer->function = inactive_task_timer;
+}
+
+#define __node_2_dle(node) \
+	rb_entry((node), struct sched_dl_entity, rb_node)
+
+#ifdef CONFIG_SMP
+
+static void inc_dl_deadline(struct dl_rq *dl_rq, u64 deadline)
+{
+	struct rq *rq = rq_of_dl_rq(dl_rq);
+
+	if (dl_rq->earliest_dl.curr == 0 ||
+	    dl_time_before(deadline, dl_rq->earliest_dl.curr)) {
+		if (dl_rq->earliest_dl.curr == 0)
+			cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_HIGHER);
+		dl_rq->earliest_dl.curr = deadline;
+		cpudl_set(&rq->rd->cpudl, rq->cpu, deadline);
+	}
+}
+
+static void dec_dl_deadline(struct dl_rq *dl_rq, u64 deadline)
+{
+	struct rq *rq = rq_of_dl_rq(dl_rq);
+
+	/*
+	 * Since we may have removed our earliest (and/or next earliest)
+	 * task we must recompute them.
+	 */
+	if (!dl_rq->dl_nr_running) {
+		dl_rq->earliest_dl.curr = 0;
+		dl_rq->earliest_dl.next = 0;
+		cpudl_clear(&rq->rd->cpudl, rq->cpu);
+		cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio.curr);
+	} else {
+		struct rb_node *leftmost = rb_first_cached(&dl_rq->root);
+		struct sched_dl_entity *entry = __node_2_dle(leftmost);
+
+		dl_rq->earliest_dl.curr = entry->deadline;
+		cpudl_set(&rq->rd->cpudl, rq->cpu, entry->deadline);
+	}
+}
+
+#else
+
+static inline void inc_dl_deadline(struct dl_rq *dl_rq, u64 deadline) {}
+static inline void dec_dl_deadline(struct dl_rq *dl_rq, u64 deadline) {}
+
+#endif /* CONFIG_SMP */
+
+static inline
+void inc_dl_tasks(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+	int prio = dl_task_of(dl_se)->prio;
+	u64 deadline = dl_se->deadline;
+
+	WARN_ON(!dl_prio(prio));
+	dl_rq->dl_nr_running++;
+	add_nr_running(rq_of_dl_rq(dl_rq), 1);
+
+	inc_dl_deadline(dl_rq, deadline);
+	inc_dl_migration(dl_se, dl_rq);
+}
+
+static inline
+void dec_dl_tasks(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+	int prio = dl_task_of(dl_se)->prio;
+
+	WARN_ON(!dl_prio(prio));
+	WARN_ON(!dl_rq->dl_nr_running);
+	dl_rq->dl_nr_running--;
+	sub_nr_running(rq_of_dl_rq(dl_rq), 1);
+
+	dec_dl_deadline(dl_rq, dl_se->deadline);
+	dec_dl_migration(dl_se, dl_rq);
+}
+
+static inline bool __dl_less(struct rb_node *a, const struct rb_node *b)
+{
+	return dl_time_before(__node_2_dle(a)->deadline, __node_2_dle(b)->deadline);
+}
+
+static inline struct sched_statistics *
+__schedstats_from_dl_se(struct sched_dl_entity *dl_se)
+{
+	return &dl_task_of(dl_se)->stats;
+}
+
+static inline void
+update_stats_wait_start_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se)
+{
+	struct sched_statistics *stats;
+
+	if (!schedstat_enabled())
+		return;
+
+	stats = __schedstats_from_dl_se(dl_se);
+	__update_stats_wait_start(rq_of_dl_rq(dl_rq), dl_task_of(dl_se), stats);
+}
+
+static inline void
+update_stats_wait_end_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se)
+{
+	struct sched_statistics *stats;
+
+	if (!schedstat_enabled())
+		return;
+
+	stats = __schedstats_from_dl_se(dl_se);
+	__update_stats_wait_end(rq_of_dl_rq(dl_rq), dl_task_of(dl_se), stats);
+}
+
+static inline void
+update_stats_enqueue_sleeper_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se)
+{
+	struct sched_statistics *stats;
+
+	if (!schedstat_enabled())
+		return;
+
+	stats = __schedstats_from_dl_se(dl_se);
+	__update_stats_enqueue_sleeper(rq_of_dl_rq(dl_rq), dl_task_of(dl_se), stats);
+}
+
+static inline void
+update_stats_enqueue_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se,
+			int flags)
+{
+	if (!schedstat_enabled())
+		return;
+
+	if (flags & ENQUEUE_WAKEUP)
+		update_stats_enqueue_sleeper_dl(dl_rq, dl_se);
+}
+
+static inline void
+update_stats_dequeue_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se,
+			int flags)
+{
+	struct task_struct *p = dl_task_of(dl_se);
+
+	if (!schedstat_enabled())
+		return;
+
+	if ((flags & DEQUEUE_SLEEP)) {
+		unsigned int state;
+
+		state = READ_ONCE(p->__state);
+		if (state & TASK_INTERRUPTIBLE)
+			__schedstat_set(p->stats.sleep_start,
+					rq_clock(rq_of_dl_rq(dl_rq)));
+
+		if (state & TASK_UNINTERRUPTIBLE)
+			__schedstat_set(p->stats.block_start,
+					rq_clock(rq_of_dl_rq(dl_rq)));
+	}
+}
+
+static void __enqueue_dl_entity(struct sched_dl_entity *dl_se)
+{
+	struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
+
+	WARN_ON_ONCE(!RB_EMPTY_NODE(&dl_se->rb_node));
+
+	rb_add_cached(&dl_se->rb_node, &dl_rq->root, __dl_less);
+
+	inc_dl_tasks(dl_se, dl_rq);
+}
+
+static void __dequeue_dl_entity(struct sched_dl_entity *dl_se)
+{
+	struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
+
+	if (RB_EMPTY_NODE(&dl_se->rb_node))
+		return;
+
+	rb_erase_cached(&dl_se->rb_node, &dl_rq->root);
+
+	RB_CLEAR_NODE(&dl_se->rb_node);
+
+	dec_dl_tasks(dl_se, dl_rq);
+}
+
+static void
+enqueue_dl_entity(struct sched_dl_entity *dl_se, int flags)
+{
+	WARN_ON_ONCE(on_dl_rq(dl_se));
+
+	update_stats_enqueue_dl(dl_rq_of_se(dl_se), dl_se, flags);
+
+	/*
+	 * If this is a wakeup or a new instance, the scheduling
+	 * parameters of the task might need updating. Otherwise,
+	 * we want a replenishment of its runtime.
+	 */
+	if (flags & ENQUEUE_WAKEUP) {
+		task_contending(dl_se, flags);
+		update_dl_entity(dl_se);
+	} else if (flags & ENQUEUE_REPLENISH) {
+		replenish_dl_entity(dl_se);
+	} else if ((flags & ENQUEUE_RESTORE) &&
+		  dl_time_before(dl_se->deadline,
+				 rq_clock(rq_of_dl_rq(dl_rq_of_se(dl_se))))) {
+		setup_new_dl_entity(dl_se);
+	}
+
+	__enqueue_dl_entity(dl_se);
+}
+
+static void dequeue_dl_entity(struct sched_dl_entity *dl_se)
+{
+	__dequeue_dl_entity(dl_se);
+}
+
+static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags)
+{
+	if (is_dl_boosted(&p->dl)) {
+		/*
+		 * Because of delays in the detection of the overrun of a
+		 * thread's runtime, it might be the case that a thread
+		 * goes to sleep in a rt mutex with negative runtime. As
+		 * a consequence, the thread will be throttled.
+		 *
+		 * While waiting for the mutex, this thread can also be
+		 * boosted via PI, resulting in a thread that is throttled
+		 * and boosted at the same time.
+		 *
+		 * In this case, the boost overrides the throttle.
+		 */
+		if (p->dl.dl_throttled) {
+			/*
+			 * The replenish timer needs to be canceled. No
+			 * problem if it fires concurrently: boosted threads
+			 * are ignored in dl_task_timer().
+			 */
+			hrtimer_try_to_cancel(&p->dl.dl_timer);
+			p->dl.dl_throttled = 0;
+		}
+	} else if (!dl_prio(p->normal_prio)) {
+		/*
+		 * Special case in which we have a !SCHED_DEADLINE task that is going
+		 * to be deboosted, but exceeds its runtime while doing so. No point in
+		 * replenishing it, as it's going to return back to its original
+		 * scheduling class after this. If it has been throttled, we need to
+		 * clear the flag, otherwise the task may wake up as throttled after
+		 * being boosted again with no means to replenish the runtime and clear
+		 * the throttle.
+		 */
+		p->dl.dl_throttled = 0;
+		if (!(flags & ENQUEUE_REPLENISH))
+			printk_deferred_once("sched: DL de-boosted task PID %d: REPLENISH flag missing\n",
+					     task_pid_nr(p));
+
+		return;
+	}
+
+	/*
+	 * Check if a constrained deadline task was activated
+	 * after the deadline but before the next period.
+	 * If that is the case, the task will be throttled and
+	 * the replenishment timer will be set to the next period.
+	 */
+	if (!p->dl.dl_throttled && !dl_is_implicit(&p->dl))
+		dl_check_constrained_dl(&p->dl);
+
+	if (p->on_rq == TASK_ON_RQ_MIGRATING || flags & ENQUEUE_RESTORE) {
+		add_rq_bw(&p->dl, &rq->dl);
+		add_running_bw(&p->dl, &rq->dl);
+	}
+
+	/*
+	 * If p is throttled, we do not enqueue it. In fact, if it exhausted
+	 * its budget it needs a replenishment and, since it now is on
+	 * its rq, the bandwidth timer callback (which clearly has not
+	 * run yet) will take care of this.
+	 * However, the active utilization does not depend on the fact
+	 * that the task is on the runqueue or not (but depends on the
+	 * task's state - in GRUB parlance, "inactive" vs "active contending").
+	 * In other words, even if a task is throttled its utilization must
+	 * be counted in the active utilization; hence, we need to call
+	 * add_running_bw().
+	 */
+	if (p->dl.dl_throttled && !(flags & ENQUEUE_REPLENISH)) {
+		if (flags & ENQUEUE_WAKEUP)
+			task_contending(&p->dl, flags);
+
+		return;
+	}
+
+	check_schedstat_required();
+	update_stats_wait_start_dl(dl_rq_of_se(&p->dl), &p->dl);
+
+	enqueue_dl_entity(&p->dl, flags);
+
+	if (!task_current(rq, p) && p->nr_cpus_allowed > 1)
+		enqueue_pushable_dl_task(rq, p);
+}
+
+static void __dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags)
+{
+	update_stats_dequeue_dl(&rq->dl, &p->dl, flags);
+	dequeue_dl_entity(&p->dl);
+	dequeue_pushable_dl_task(rq, p);
+}
+
+static void dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags)
+{
+	update_curr_dl(rq);
+	__dequeue_task_dl(rq, p, flags);
+
+	if (p->on_rq == TASK_ON_RQ_MIGRATING || flags & DEQUEUE_SAVE) {
+		sub_running_bw(&p->dl, &rq->dl);
+		sub_rq_bw(&p->dl, &rq->dl);
+	}
+
+	/*
+	 * This check allows to start the inactive timer (or to immediately
+	 * decrease the active utilization, if needed) in two cases:
+	 * when the task blocks and when it is terminating
+	 * (p->state == TASK_DEAD). We can handle the two cases in the same
+	 * way, because from GRUB's point of view the same thing is happening
+	 * (the task moves from "active contending" to "active non contending"
+	 * or "inactive")
+	 */
+	if (flags & DEQUEUE_SLEEP)
+		task_non_contending(p);
+}
+
+/*
+ * Yield task semantic for -deadline tasks is:
+ *
+ *   get off from the CPU until our next instance, with
+ *   a new runtime. This is of little use now, since we
+ *   don't have a bandwidth reclaiming mechanism. Anyway,
+ *   bandwidth reclaiming is planned for the future, and
+ *   yield_task_dl will indicate that some spare budget
+ *   is available for other task instances to use it.
+ */
+static void yield_task_dl(struct rq *rq)
+{
+	/*
+	 * We make the task go to sleep until its current deadline by
+	 * forcing its runtime to zero. This way, update_curr_dl() stops
+	 * it and the bandwidth timer will wake it up and will give it
+	 * new scheduling parameters (thanks to dl_yielded=1).
+	 */
+	rq->curr->dl.dl_yielded = 1;
+
+	update_rq_clock(rq);
+	update_curr_dl(rq);
+	/*
+	 * Tell update_rq_clock() that we've just updated,
+	 * so we don't do microscopic update in schedule()
+	 * and double the fastpath cost.
+	 */
+	rq_clock_skip_update(rq);
+}
+
+#ifdef CONFIG_SMP
+
+static inline bool dl_task_is_earliest_deadline(struct task_struct *p,
+						 struct rq *rq)
+{
+	return (!rq->dl.dl_nr_running ||
+		dl_time_before(p->dl.deadline,
+			       rq->dl.earliest_dl.curr));
+}
+
+static int find_later_rq(struct task_struct *task);
+
+static int
+select_task_rq_dl(struct task_struct *p, int cpu, int flags)
+{
+	struct task_struct *curr;
+	bool select_rq;
+	struct rq *rq;
+
+	if (!(flags & WF_TTWU))
+		goto out;
+
+	rq = cpu_rq(cpu);
+
+	rcu_read_lock();
+	curr = READ_ONCE(rq->curr); /* unlocked access */
+
+	/*
+	 * If we are dealing with a -deadline task, we must
+	 * decide where to wake it up.
+	 * If it has a later deadline and the current task
+	 * on this rq can't move (provided the waking task
+	 * can!) we prefer to send it somewhere else. On the
+	 * other hand, if it has a shorter deadline, we
+	 * try to make it stay here, it might be important.
+	 */
+	select_rq = unlikely(dl_task(curr)) &&
+		    (curr->nr_cpus_allowed < 2 ||
+		     !dl_entity_preempt(&p->dl, &curr->dl)) &&
+		    p->nr_cpus_allowed > 1;
+
+	/*
+	 * Take the capacity of the CPU into account to
+	 * ensure it fits the requirement of the task.
+	 */
+	if (sched_asym_cpucap_active())
+		select_rq |= !dl_task_fits_capacity(p, cpu);
+
+	if (select_rq) {
+		int target = find_later_rq(p);
+
+		if (target != -1 &&
+		    dl_task_is_earliest_deadline(p, cpu_rq(target)))
+			cpu = target;
+	}
+	rcu_read_unlock();
+
+out:
+	return cpu;
+}
+
+static void migrate_task_rq_dl(struct task_struct *p, int new_cpu __maybe_unused)
+{
+	struct rq_flags rf;
+	struct rq *rq;
+
+	if (READ_ONCE(p->__state) != TASK_WAKING)
+		return;
+
+	rq = task_rq(p);
+	/*
+	 * Since p->state == TASK_WAKING, set_task_cpu() has been called
+	 * from try_to_wake_up(). Hence, p->pi_lock is locked, but
+	 * rq->lock is not... So, lock it
+	 */
+	rq_lock(rq, &rf);
+	if (p->dl.dl_non_contending) {
+		update_rq_clock(rq);
+		sub_running_bw(&p->dl, &rq->dl);
+		p->dl.dl_non_contending = 0;
+		/*
+		 * If the timer handler is currently running and the
+		 * timer cannot be canceled, inactive_task_timer()
+		 * will see that dl_not_contending is not set, and
+		 * will not touch the rq's active utilization,
+		 * so we are still safe.
+		 */
+		if (hrtimer_try_to_cancel(&p->dl.inactive_timer) == 1)
+			put_task_struct(p);
+	}
+	sub_rq_bw(&p->dl, &rq->dl);
+	rq_unlock(rq, &rf);
+}
+
+static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p)
+{
+	/*
+	 * Current can't be migrated, useless to reschedule,
+	 * let's hope p can move out.
+	 */
+	if (rq->curr->nr_cpus_allowed == 1 ||
+	    !cpudl_find(&rq->rd->cpudl, rq->curr, NULL))
+		return;
+
+	/*
+	 * p is migratable, so let's not schedule it and
+	 * see if it is pushed or pulled somewhere else.
+	 */
+	if (p->nr_cpus_allowed != 1 &&
+	    cpudl_find(&rq->rd->cpudl, p, NULL))
+		return;
+
+	resched_curr(rq);
+}
+
+static int balance_dl(struct rq *rq, struct task_struct *p, struct rq_flags *rf)
+{
+	if (!on_dl_rq(&p->dl) && need_pull_dl_task(rq, p)) {
+		/*
+		 * This is OK, because current is on_cpu, which avoids it being
+		 * picked for load-balance and preemption/IRQs are still
+		 * disabled avoiding further scheduler activity on it and we've
+		 * not yet started the picking loop.
+		 */
+		rq_unpin_lock(rq, rf);
+		pull_dl_task(rq);
+		rq_repin_lock(rq, rf);
+	}
+
+	return sched_stop_runnable(rq) || sched_dl_runnable(rq);
+}
+#endif /* CONFIG_SMP */
+
+/*
+ * Only called when both the current and waking task are -deadline
+ * tasks.
+ */
+static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p,
+				  int flags)
+{
+	if (dl_entity_preempt(&p->dl, &rq->curr->dl)) {
+		resched_curr(rq);
+		return;
+	}
+
+#ifdef CONFIG_SMP
+	/*
+	 * In the unlikely case current and p have the same deadline
+	 * let us try to decide what's the best thing to do...
+	 */
+	if ((p->dl.deadline == rq->curr->dl.deadline) &&
+	    !test_tsk_need_resched(rq->curr))
+		check_preempt_equal_dl(rq, p);
+#endif /* CONFIG_SMP */
+}
+
+#ifdef CONFIG_SCHED_HRTICK
+static void start_hrtick_dl(struct rq *rq, struct task_struct *p)
+{
+	hrtick_start(rq, p->dl.runtime);
+}
+#else /* !CONFIG_SCHED_HRTICK */
+static void start_hrtick_dl(struct rq *rq, struct task_struct *p)
+{
+}
+#endif
+
+static void set_next_task_dl(struct rq *rq, struct task_struct *p, bool first)
+{
+	struct sched_dl_entity *dl_se = &p->dl;
+	struct dl_rq *dl_rq = &rq->dl;
+
+	p->se.exec_start = rq_clock_task(rq);
+	if (on_dl_rq(&p->dl))
+		update_stats_wait_end_dl(dl_rq, dl_se);
+
+	/* You can't push away the running task */
+	dequeue_pushable_dl_task(rq, p);
+
+	if (!first)
+		return;
+
+	if (hrtick_enabled_dl(rq))
+		start_hrtick_dl(rq, p);
+
+	if (rq->curr->sched_class != &dl_sched_class)
+		update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 0);
+
+	deadline_queue_push_tasks(rq);
+}
+
+static struct sched_dl_entity *pick_next_dl_entity(struct dl_rq *dl_rq)
+{
+	struct rb_node *left = rb_first_cached(&dl_rq->root);
+
+	if (!left)
+		return NULL;
+
+	return __node_2_dle(left);
+}
+
+static struct task_struct *pick_task_dl(struct rq *rq)
+{
+	struct sched_dl_entity *dl_se;
+	struct dl_rq *dl_rq = &rq->dl;
+	struct task_struct *p;
+
+	if (!sched_dl_runnable(rq))
+		return NULL;
+
+	dl_se = pick_next_dl_entity(dl_rq);
+	WARN_ON_ONCE(!dl_se);
+	p = dl_task_of(dl_se);
+
+	return p;
+}
+
+static struct task_struct *pick_next_task_dl(struct rq *rq)
+{
+	struct task_struct *p;
+
+	p = pick_task_dl(rq);
+	if (p)
+		set_next_task_dl(rq, p, true);
+
+	return p;
+}
+
+static void put_prev_task_dl(struct rq *rq, struct task_struct *p)
+{
+	struct sched_dl_entity *dl_se = &p->dl;
+	struct dl_rq *dl_rq = &rq->dl;
+
+	if (on_dl_rq(&p->dl))
+		update_stats_wait_start_dl(dl_rq, dl_se);
+
+	update_curr_dl(rq);
+
+	update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 1);
+	if (on_dl_rq(&p->dl) && p->nr_cpus_allowed > 1)
+		enqueue_pushable_dl_task(rq, p);
+}
+
+/*
+ * scheduler tick hitting a task of our scheduling class.
+ *
+ * NOTE: This function can be called remotely by the tick offload that
+ * goes along full dynticks. Therefore no local assumption can be made
+ * and everything must be accessed through the @rq and @curr passed in
+ * parameters.
+ */
+static void task_tick_dl(struct rq *rq, struct task_struct *p, int queued)
+{
+	update_curr_dl(rq);
+
+	update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 1);
+	/*
+	 * Even when we have runtime, update_curr_dl() might have resulted in us
+	 * not being the leftmost task anymore. In that case NEED_RESCHED will
+	 * be set and schedule() will start a new hrtick for the next task.
+	 */
+	if (hrtick_enabled_dl(rq) && queued && p->dl.runtime > 0 &&
+	    is_leftmost(p, &rq->dl))
+		start_hrtick_dl(rq, p);
+}
+
+static void task_fork_dl(struct task_struct *p)
+{
+	/*
+	 * SCHED_DEADLINE tasks cannot fork and this is achieved through
+	 * sched_fork()
+	 */
+}
+
+#ifdef CONFIG_SMP
+
+/* Only try algorithms three times */
+#define DL_MAX_TRIES 3
+
+static int pick_dl_task(struct rq *rq, struct task_struct *p, int cpu)
+{
+	if (!task_on_cpu(rq, p) &&
+	    cpumask_test_cpu(cpu, &p->cpus_mask))
+		return 1;
+	return 0;
+}
+
+/*
+ * Return the earliest pushable rq's task, which is suitable to be executed
+ * on the CPU, NULL otherwise:
+ */
+static struct task_struct *pick_earliest_pushable_dl_task(struct rq *rq, int cpu)
+{
+	struct task_struct *p = NULL;
+	struct rb_node *next_node;
+
+	if (!has_pushable_dl_tasks(rq))
+		return NULL;
+
+	next_node = rb_first_cached(&rq->dl.pushable_dl_tasks_root);
+
+next_node:
+	if (next_node) {
+		p = __node_2_pdl(next_node);
+
+		if (pick_dl_task(rq, p, cpu))
+			return p;
+
+		next_node = rb_next(next_node);
+		goto next_node;
+	}
+
+	return NULL;
+}
+
+static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask_dl);
+
+static int find_later_rq(struct task_struct *task)
+{
+	struct sched_domain *sd;
+	struct cpumask *later_mask = this_cpu_cpumask_var_ptr(local_cpu_mask_dl);
+	int this_cpu = smp_processor_id();
+	int cpu = task_cpu(task);
+
+	/* Make sure the mask is initialized first */
+	if (unlikely(!later_mask))
+		return -1;
+
+	if (task->nr_cpus_allowed == 1)
+		return -1;
+
+	/*
+	 * We have to consider system topology and task affinity
+	 * first, then we can look for a suitable CPU.
+	 */
+	if (!cpudl_find(&task_rq(task)->rd->cpudl, task, later_mask))
+		return -1;
+
+	/*
+	 * If we are here, some targets have been found, including
+	 * the most suitable which is, among the runqueues where the
+	 * current tasks have later deadlines than the task's one, the
+	 * rq with the latest possible one.
+	 *
+	 * Now we check how well this matches with task's
+	 * affinity and system topology.
+	 *
+	 * The last CPU where the task run is our first
+	 * guess, since it is most likely cache-hot there.
+	 */
+	if (cpumask_test_cpu(cpu, later_mask))
+		return cpu;
+	/*
+	 * Check if this_cpu is to be skipped (i.e., it is
+	 * not in the mask) or not.
+	 */
+	if (!cpumask_test_cpu(this_cpu, later_mask))
+		this_cpu = -1;
+
+	rcu_read_lock();
+	for_each_domain(cpu, sd) {
+		if (sd->flags & SD_WAKE_AFFINE) {
+			int best_cpu;
+
+			/*
+			 * If possible, preempting this_cpu is
+			 * cheaper than migrating.
+			 */
+			if (this_cpu != -1 &&
+			    cpumask_test_cpu(this_cpu, sched_domain_span(sd))) {
+				rcu_read_unlock();
+				return this_cpu;
+			}
+
+			best_cpu = cpumask_any_and_distribute(later_mask,
+							      sched_domain_span(sd));
+			/*
+			 * Last chance: if a CPU being in both later_mask
+			 * and current sd span is valid, that becomes our
+			 * choice. Of course, the latest possible CPU is
+			 * already under consideration through later_mask.
+			 */
+			if (best_cpu < nr_cpu_ids) {
+				rcu_read_unlock();
+				return best_cpu;
+			}
+		}
+	}
+	rcu_read_unlock();
+
+	/*
+	 * At this point, all our guesses failed, we just return
+	 * 'something', and let the caller sort the things out.
+	 */
+	if (this_cpu != -1)
+		return this_cpu;
+
+	cpu = cpumask_any_distribute(later_mask);
+	if (cpu < nr_cpu_ids)
+		return cpu;
+
+	return -1;
+}
+
+/* Locks the rq it finds */
+static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq)
+{
+	struct rq *later_rq = NULL;
+	int tries;
+	int cpu;
+
+	for (tries = 0; tries < DL_MAX_TRIES; tries++) {
+		cpu = find_later_rq(task);
+
+		if ((cpu == -1) || (cpu == rq->cpu))
+			break;
+
+		later_rq = cpu_rq(cpu);
+
+		if (!dl_task_is_earliest_deadline(task, later_rq)) {
+			/*
+			 * Target rq has tasks of equal or earlier deadline,
+			 * retrying does not release any lock and is unlikely
+			 * to yield a different result.
+			 */
+			later_rq = NULL;
+			break;
+		}
+
+		/* Retry if something changed. */
+		if (double_lock_balance(rq, later_rq)) {
+			if (unlikely(task_rq(task) != rq ||
+				     !cpumask_test_cpu(later_rq->cpu, &task->cpus_mask) ||
+				     task_on_cpu(rq, task) ||
+				     !dl_task(task) ||
+				     is_migration_disabled(task) ||
+				     !task_on_rq_queued(task))) {
+				double_unlock_balance(rq, later_rq);
+				later_rq = NULL;
+				break;
+			}
+		}
+
+		/*
+		 * If the rq we found has no -deadline task, or
+		 * its earliest one has a later deadline than our
+		 * task, the rq is a good one.
+		 */
+		if (dl_task_is_earliest_deadline(task, later_rq))
+			break;
+
+		/* Otherwise we try again. */
+		double_unlock_balance(rq, later_rq);
+		later_rq = NULL;
+	}
+
+	return later_rq;
+}
+
+static struct task_struct *pick_next_pushable_dl_task(struct rq *rq)
+{
+	struct task_struct *p;
+
+	if (!has_pushable_dl_tasks(rq))
+		return NULL;
+
+	p = __node_2_pdl(rb_first_cached(&rq->dl.pushable_dl_tasks_root));
+
+	WARN_ON_ONCE(rq->cpu != task_cpu(p));
+	WARN_ON_ONCE(task_current(rq, p));
+	WARN_ON_ONCE(p->nr_cpus_allowed <= 1);
+
+	WARN_ON_ONCE(!task_on_rq_queued(p));
+	WARN_ON_ONCE(!dl_task(p));
+
+	return p;
+}
+
+/*
+ * See if the non running -deadline tasks on this rq
+ * can be sent to some other CPU where they can preempt
+ * and start executing.
+ */
+static int push_dl_task(struct rq *rq)
+{
+	struct task_struct *next_task;
+	struct rq *later_rq;
+	int ret = 0;
+
+	if (!rq->dl.overloaded)
+		return 0;
+
+	next_task = pick_next_pushable_dl_task(rq);
+	if (!next_task)
+		return 0;
+
+retry:
+	/*
+	 * If next_task preempts rq->curr, and rq->curr
+	 * can move away, it makes sense to just reschedule
+	 * without going further in pushing next_task.
+	 */
+	if (dl_task(rq->curr) &&
+	    dl_time_before(next_task->dl.deadline, rq->curr->dl.deadline) &&
+	    rq->curr->nr_cpus_allowed > 1) {
+		resched_curr(rq);
+		return 0;
+	}
+
+	if (is_migration_disabled(next_task))
+		return 0;
+
+	if (WARN_ON(next_task == rq->curr))
+		return 0;
+
+	/* We might release rq lock */
+	get_task_struct(next_task);
+
+	/* Will lock the rq it'll find */
+	later_rq = find_lock_later_rq(next_task, rq);
+	if (!later_rq) {
+		struct task_struct *task;
+
+		/*
+		 * We must check all this again, since
+		 * find_lock_later_rq releases rq->lock and it is
+		 * then possible that next_task has migrated.
+		 */
+		task = pick_next_pushable_dl_task(rq);
+		if (task == next_task) {
+			/*
+			 * The task is still there. We don't try
+			 * again, some other CPU will pull it when ready.
+			 */
+			goto out;
+		}
+
+		if (!task)
+			/* No more tasks */
+			goto out;
+
+		put_task_struct(next_task);
+		next_task = task;
+		goto retry;
+	}
+
+	deactivate_task(rq, next_task, 0);
+	set_task_cpu(next_task, later_rq->cpu);
+	activate_task(later_rq, next_task, 0);
+	ret = 1;
+
+	resched_curr(later_rq);
+
+	double_unlock_balance(rq, later_rq);
+
+out:
+	put_task_struct(next_task);
+
+	return ret;
+}
+
+static void push_dl_tasks(struct rq *rq)
+{
+	/* push_dl_task() will return true if it moved a -deadline task */
+	while (push_dl_task(rq))
+		;
+}
+
+static void pull_dl_task(struct rq *this_rq)
+{
+	int this_cpu = this_rq->cpu, cpu;
+	struct task_struct *p, *push_task;
+	bool resched = false;
+	struct rq *src_rq;
+	u64 dmin = LONG_MAX;
+
+	if (likely(!dl_overloaded(this_rq)))
+		return;
+
+	/*
+	 * Match the barrier from dl_set_overloaded; this guarantees that if we
+	 * see overloaded we must also see the dlo_mask bit.
+	 */
+	smp_rmb();
+
+	for_each_cpu(cpu, this_rq->rd->dlo_mask) {
+		if (this_cpu == cpu)
+			continue;
+
+		src_rq = cpu_rq(cpu);
+
+		/*
+		 * It looks racy, abd it is! However, as in sched_rt.c,
+		 * we are fine with this.
+		 */
+		if (this_rq->dl.dl_nr_running &&
+		    dl_time_before(this_rq->dl.earliest_dl.curr,
+				   src_rq->dl.earliest_dl.next))
+			continue;
+
+		/* Might drop this_rq->lock */
+		push_task = NULL;
+		double_lock_balance(this_rq, src_rq);
+
+		/*
+		 * If there are no more pullable tasks on the
+		 * rq, we're done with it.
+		 */
+		if (src_rq->dl.dl_nr_running <= 1)
+			goto skip;
+
+		p = pick_earliest_pushable_dl_task(src_rq, this_cpu);
+
+		/*
+		 * We found a task to be pulled if:
+		 *  - it preempts our current (if there's one),
+		 *  - it will preempt the last one we pulled (if any).
+		 */
+		if (p && dl_time_before(p->dl.deadline, dmin) &&
+		    dl_task_is_earliest_deadline(p, this_rq)) {
+			WARN_ON(p == src_rq->curr);
+			WARN_ON(!task_on_rq_queued(p));
+
+			/*
+			 * Then we pull iff p has actually an earlier
+			 * deadline than the current task of its runqueue.
+			 */
+			if (dl_time_before(p->dl.deadline,
+					   src_rq->curr->dl.deadline))
+				goto skip;
+
+			if (is_migration_disabled(p)) {
+				push_task = get_push_task(src_rq);
+			} else {
+				deactivate_task(src_rq, p, 0);
+				set_task_cpu(p, this_cpu);
+				activate_task(this_rq, p, 0);
+				dmin = p->dl.deadline;
+				resched = true;
+			}
+
+			/* Is there any other task even earlier? */
+		}
+skip:
+		double_unlock_balance(this_rq, src_rq);
+
+		if (push_task) {
+			preempt_disable();
+			raw_spin_rq_unlock(this_rq);
+			stop_one_cpu_nowait(src_rq->cpu, push_cpu_stop,
+					    push_task, &src_rq->push_work);
+			preempt_enable();
+			raw_spin_rq_lock(this_rq);
+		}
+	}
+
+	if (resched)
+		resched_curr(this_rq);
+}
+
+/*
+ * Since the task is not running and a reschedule is not going to happen
+ * anytime soon on its runqueue, we try pushing it away now.
+ */
+static void task_woken_dl(struct rq *rq, struct task_struct *p)
+{
+	if (!task_on_cpu(rq, p) &&
+	    !test_tsk_need_resched(rq->curr) &&
+	    p->nr_cpus_allowed > 1 &&
+	    dl_task(rq->curr) &&
+	    (rq->curr->nr_cpus_allowed < 2 ||
+	     !dl_entity_preempt(&p->dl, &rq->curr->dl))) {
+		push_dl_tasks(rq);
+	}
+}
+
+static void set_cpus_allowed_dl(struct task_struct *p,
+				struct affinity_context *ctx)
+{
+	struct root_domain *src_rd;
+	struct rq *rq;
+
+	WARN_ON_ONCE(!dl_task(p));
+
+	rq = task_rq(p);
+	src_rd = rq->rd;
+	/*
+	 * Migrating a SCHED_DEADLINE task between exclusive
+	 * cpusets (different root_domains) entails a bandwidth
+	 * update. We already made space for us in the destination
+	 * domain (see cpuset_can_attach()).
+	 */
+	if (!cpumask_intersects(src_rd->span, ctx->new_mask)) {
+		struct dl_bw *src_dl_b;
+
+		src_dl_b = dl_bw_of(cpu_of(rq));
+		/*
+		 * We now free resources of the root_domain we are migrating
+		 * off. In the worst case, sched_setattr() may temporary fail
+		 * until we complete the update.
+		 */
+		raw_spin_lock(&src_dl_b->lock);
+		__dl_sub(src_dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p)));
+		raw_spin_unlock(&src_dl_b->lock);
+	}
+
+	set_cpus_allowed_common(p, ctx);
+}
+
+/* Assumes rq->lock is held */
+static void rq_online_dl(struct rq *rq)
+{
+	if (rq->dl.overloaded)
+		dl_set_overload(rq);
+
+	cpudl_set_freecpu(&rq->rd->cpudl, rq->cpu);
+	if (rq->dl.dl_nr_running > 0)
+		cpudl_set(&rq->rd->cpudl, rq->cpu, rq->dl.earliest_dl.curr);
+}
+
+/* Assumes rq->lock is held */
+static void rq_offline_dl(struct rq *rq)
+{
+	if (rq->dl.overloaded)
+		dl_clear_overload(rq);
+
+	cpudl_clear(&rq->rd->cpudl, rq->cpu);
+	cpudl_clear_freecpu(&rq->rd->cpudl, rq->cpu);
+}
+
+void __init init_sched_dl_class(void)
+{
+	unsigned int i;
+
+	for_each_possible_cpu(i)
+		zalloc_cpumask_var_node(&per_cpu(local_cpu_mask_dl, i),
+					GFP_KERNEL, cpu_to_node(i));
+}
+
+void dl_add_task_root_domain(struct task_struct *p)
+{
+	struct rq_flags rf;
+	struct rq *rq;
+	struct dl_bw *dl_b;
+
+	raw_spin_lock_irqsave(&p->pi_lock, rf.flags);
+	if (!dl_task(p)) {
+		raw_spin_unlock_irqrestore(&p->pi_lock, rf.flags);
+		return;
+	}
+
+	rq = __task_rq_lock(p, &rf);
+
+	dl_b = &rq->rd->dl_bw;
+	raw_spin_lock(&dl_b->lock);
+
+	__dl_add(dl_b, p->dl.dl_bw, cpumask_weight(rq->rd->span));
+
+	raw_spin_unlock(&dl_b->lock);
+
+	task_rq_unlock(rq, p, &rf);
+}
+
+void dl_clear_root_domain(struct root_domain *rd)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&rd->dl_bw.lock, flags);
+	rd->dl_bw.total_bw = 0;
+	raw_spin_unlock_irqrestore(&rd->dl_bw.lock, flags);
+}
+
+#endif /* CONFIG_SMP */
+
+static void switched_from_dl(struct rq *rq, struct task_struct *p)
+{
+	/*
+	 * task_non_contending() can start the "inactive timer" (if the 0-lag
+	 * time is in the future). If the task switches back to dl before
+	 * the "inactive timer" fires, it can continue to consume its current
+	 * runtime using its current deadline. If it stays outside of
+	 * SCHED_DEADLINE until the 0-lag time passes, inactive_task_timer()
+	 * will reset the task parameters.
+	 */
+	if (task_on_rq_queued(p) && p->dl.dl_runtime)
+		task_non_contending(p);
+
+	/*
+	 * In case a task is setscheduled out from SCHED_DEADLINE we need to
+	 * keep track of that on its cpuset (for correct bandwidth tracking).
+	 */
+	dec_dl_tasks_cs(p);
+
+	if (!task_on_rq_queued(p)) {
+		/*
+		 * Inactive timer is armed. However, p is leaving DEADLINE and
+		 * might migrate away from this rq while continuing to run on
+		 * some other class. We need to remove its contribution from
+		 * this rq running_bw now, or sub_rq_bw (below) will complain.
+		 */
+		if (p->dl.dl_non_contending)
+			sub_running_bw(&p->dl, &rq->dl);
+		sub_rq_bw(&p->dl, &rq->dl);
+	}
+
+	/*
+	 * We cannot use inactive_task_timer() to invoke sub_running_bw()
+	 * at the 0-lag time, because the task could have been migrated
+	 * while SCHED_OTHER in the meanwhile.
+	 */
+	if (p->dl.dl_non_contending)
+		p->dl.dl_non_contending = 0;
+
+	/*
+	 * Since this might be the only -deadline task on the rq,
+	 * this is the right place to try to pull some other one
+	 * from an overloaded CPU, if any.
+	 */
+	if (!task_on_rq_queued(p) || rq->dl.dl_nr_running)
+		return;
+
+	deadline_queue_pull_task(rq);
+}
+
+/*
+ * When switching to -deadline, we may overload the rq, then
+ * we try to push someone off, if possible.
+ */
+static void switched_to_dl(struct rq *rq, struct task_struct *p)
+{
+	if (hrtimer_try_to_cancel(&p->dl.inactive_timer) == 1)
+		put_task_struct(p);
+
+	/*
+	 * In case a task is setscheduled to SCHED_DEADLINE we need to keep
+	 * track of that on its cpuset (for correct bandwidth tracking).
+	 */
+	inc_dl_tasks_cs(p);
+
+	/* If p is not queued we will update its parameters at next wakeup. */
+	if (!task_on_rq_queued(p)) {
+		add_rq_bw(&p->dl, &rq->dl);
+
+		return;
+	}
+
+	if (rq->curr != p) {
+#ifdef CONFIG_SMP
+		if (p->nr_cpus_allowed > 1 && rq->dl.overloaded)
+			deadline_queue_push_tasks(rq);
+#endif
+		if (dl_task(rq->curr))
+			check_preempt_curr_dl(rq, p, 0);
+		else
+			resched_curr(rq);
+	} else {
+		update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 0);
+	}
+}
+
+/*
+ * If the scheduling parameters of a -deadline task changed,
+ * a push or pull operation might be needed.
+ */
+static void prio_changed_dl(struct rq *rq, struct task_struct *p,
+			    int oldprio)
+{
+	if (!task_on_rq_queued(p))
+		return;
+
+#ifdef CONFIG_SMP
+	/*
+	 * This might be too much, but unfortunately
+	 * we don't have the old deadline value, and
+	 * we can't argue if the task is increasing
+	 * or lowering its prio, so...
+	 */
+	if (!rq->dl.overloaded)
+		deadline_queue_pull_task(rq);
+
+	if (task_current(rq, p)) {
+		/*
+		 * If we now have a earlier deadline task than p,
+		 * then reschedule, provided p is still on this
+		 * runqueue.
+		 */
+		if (dl_time_before(rq->dl.earliest_dl.curr, p->dl.deadline))
+			resched_curr(rq);
+	} else {
+		/*
+		 * Current may not be deadline in case p was throttled but we
+		 * have just replenished it (e.g. rt_mutex_setprio()).
+		 *
+		 * Otherwise, if p was given an earlier deadline, reschedule.
+		 */
+		if (!dl_task(rq->curr) ||
+		    dl_time_before(p->dl.deadline, rq->curr->dl.deadline))
+			resched_curr(rq);
+	}
+#else
+	/*
+	 * We don't know if p has a earlier or later deadline, so let's blindly
+	 * set a (maybe not needed) rescheduling point.
+	 */
+	resched_curr(rq);
+#endif
+}
+
+#ifdef CONFIG_SCHED_CORE
+static int task_is_throttled_dl(struct task_struct *p, int cpu)
+{
+	return p->dl.dl_throttled;
+}
+#endif
+
+DEFINE_SCHED_CLASS(dl) = {
+
+	.enqueue_task		= enqueue_task_dl,
+	.dequeue_task		= dequeue_task_dl,
+	.yield_task		= yield_task_dl,
+
+	.check_preempt_curr	= check_preempt_curr_dl,
+
+	.pick_next_task		= pick_next_task_dl,
+	.put_prev_task		= put_prev_task_dl,
+	.set_next_task		= set_next_task_dl,
+
+#ifdef CONFIG_SMP
+	.balance		= balance_dl,
+	.pick_task		= pick_task_dl,
+	.select_task_rq		= select_task_rq_dl,
+	.migrate_task_rq	= migrate_task_rq_dl,
+	.set_cpus_allowed       = set_cpus_allowed_dl,
+	.rq_online              = rq_online_dl,
+	.rq_offline             = rq_offline_dl,
+	.task_woken		= task_woken_dl,
+	.find_lock_rq		= find_lock_later_rq,
+#endif
+
+	.task_tick		= task_tick_dl,
+	.task_fork              = task_fork_dl,
+
+	.prio_changed           = prio_changed_dl,
+	.switched_from		= switched_from_dl,
+	.switched_to		= switched_to_dl,
+
+	.update_curr		= update_curr_dl,
+#ifdef CONFIG_SCHED_CORE
+	.task_is_throttled	= task_is_throttled_dl,
+#endif
+};
+
+/* Used for dl_bw check and update, used under sched_rt_handler()::mutex */
+static u64 dl_generation;
+
+int sched_dl_global_validate(void)
+{
+	u64 runtime = global_rt_runtime();
+	u64 period = global_rt_period();
+	u64 new_bw = to_ratio(period, runtime);
+	u64 gen = ++dl_generation;
+	struct dl_bw *dl_b;
+	int cpu, cpus, ret = 0;
+	unsigned long flags;
+
+	/*
+	 * Here we want to check the bandwidth not being set to some
+	 * value smaller than the currently allocated bandwidth in
+	 * any of the root_domains.
+	 */
+	for_each_possible_cpu(cpu) {
+		rcu_read_lock_sched();
+
+		if (dl_bw_visited(cpu, gen))
+			goto next;
+
+		dl_b = dl_bw_of(cpu);
+		cpus = dl_bw_cpus(cpu);
+
+		raw_spin_lock_irqsave(&dl_b->lock, flags);
+		if (new_bw * cpus < dl_b->total_bw)
+			ret = -EBUSY;
+		raw_spin_unlock_irqrestore(&dl_b->lock, flags);
+
+next:
+		rcu_read_unlock_sched();
+
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
+static void init_dl_rq_bw_ratio(struct dl_rq *dl_rq)
+{
+	if (global_rt_runtime() == RUNTIME_INF) {
+		dl_rq->bw_ratio = 1 << RATIO_SHIFT;
+		dl_rq->max_bw = dl_rq->extra_bw = 1 << BW_SHIFT;
+	} else {
+		dl_rq->bw_ratio = to_ratio(global_rt_runtime(),
+			  global_rt_period()) >> (BW_SHIFT - RATIO_SHIFT);
+		dl_rq->max_bw = dl_rq->extra_bw =
+			to_ratio(global_rt_period(), global_rt_runtime());
+	}
+}
+
+void sched_dl_do_global(void)
+{
+	u64 new_bw = -1;
+	u64 gen = ++dl_generation;
+	struct dl_bw *dl_b;
+	int cpu;
+	unsigned long flags;
+
+	if (global_rt_runtime() != RUNTIME_INF)
+		new_bw = to_ratio(global_rt_period(), global_rt_runtime());
+
+	for_each_possible_cpu(cpu) {
+		rcu_read_lock_sched();
+
+		if (dl_bw_visited(cpu, gen)) {
+			rcu_read_unlock_sched();
+			continue;
+		}
+
+		dl_b = dl_bw_of(cpu);
+
+		raw_spin_lock_irqsave(&dl_b->lock, flags);
+		dl_b->bw = new_bw;
+		raw_spin_unlock_irqrestore(&dl_b->lock, flags);
+
+		rcu_read_unlock_sched();
+		init_dl_rq_bw_ratio(&cpu_rq(cpu)->dl);
+	}
+}
+
+/*
+ * We must be sure that accepting a new task (or allowing changing the
+ * parameters of an existing one) is consistent with the bandwidth
+ * constraints. If yes, this function also accordingly updates the currently
+ * allocated bandwidth to reflect the new situation.
+ *
+ * This function is called while holding p's rq->lock.
+ */
+int sched_dl_overflow(struct task_struct *p, int policy,
+		      const struct sched_attr *attr)
+{
+	u64 period = attr->sched_period ?: attr->sched_deadline;
+	u64 runtime = attr->sched_runtime;
+	u64 new_bw = dl_policy(policy) ? to_ratio(period, runtime) : 0;
+	int cpus, err = -1, cpu = task_cpu(p);
+	struct dl_bw *dl_b = dl_bw_of(cpu);
+	unsigned long cap;
+
+	if (attr->sched_flags & SCHED_FLAG_SUGOV)
+		return 0;
+
+	/* !deadline task may carry old deadline bandwidth */
+	if (new_bw == p->dl.dl_bw && task_has_dl_policy(p))
+		return 0;
+
+	/*
+	 * Either if a task, enters, leave, or stays -deadline but changes
+	 * its parameters, we may need to update accordingly the total
+	 * allocated bandwidth of the container.
+	 */
+	raw_spin_lock(&dl_b->lock);
+	cpus = dl_bw_cpus(cpu);
+	cap = dl_bw_capacity(cpu);
+
+	if (dl_policy(policy) && !task_has_dl_policy(p) &&
+	    !__dl_overflow(dl_b, cap, 0, new_bw)) {
+		if (hrtimer_active(&p->dl.inactive_timer))
+			__dl_sub(dl_b, p->dl.dl_bw, cpus);
+		__dl_add(dl_b, new_bw, cpus);
+		err = 0;
+	} else if (dl_policy(policy) && task_has_dl_policy(p) &&
+		   !__dl_overflow(dl_b, cap, p->dl.dl_bw, new_bw)) {
+		/*
+		 * XXX this is slightly incorrect: when the task
+		 * utilization decreases, we should delay the total
+		 * utilization change until the task's 0-lag point.
+		 * But this would require to set the task's "inactive
+		 * timer" when the task is not inactive.
+		 */
+		__dl_sub(dl_b, p->dl.dl_bw, cpus);
+		__dl_add(dl_b, new_bw, cpus);
+		dl_change_utilization(p, new_bw);
+		err = 0;
+	} else if (!dl_policy(policy) && task_has_dl_policy(p)) {
+		/*
+		 * Do not decrease the total deadline utilization here,
+		 * switched_from_dl() will take care to do it at the correct
+		 * (0-lag) time.
+		 */
+		err = 0;
+	}
+	raw_spin_unlock(&dl_b->lock);
+
+	return err;
+}
+
+/*
+ * This function initializes the sched_dl_entity of a newly becoming
+ * SCHED_DEADLINE task.
+ *
+ * Only the static values are considered here, the actual runtime and the
+ * absolute deadline will be properly calculated when the task is enqueued
+ * for the first time with its new policy.
+ */
+void __setparam_dl(struct task_struct *p, const struct sched_attr *attr)
+{
+	struct sched_dl_entity *dl_se = &p->dl;
+
+	dl_se->dl_runtime = attr->sched_runtime;
+	dl_se->dl_deadline = attr->sched_deadline;
+	dl_se->dl_period = attr->sched_period ?: dl_se->dl_deadline;
+	dl_se->flags = attr->sched_flags & SCHED_DL_FLAGS;
+	dl_se->dl_bw = to_ratio(dl_se->dl_period, dl_se->dl_runtime);
+	dl_se->dl_density = to_ratio(dl_se->dl_deadline, dl_se->dl_runtime);
+}
+
+void __getparam_dl(struct task_struct *p, struct sched_attr *attr)
+{
+	struct sched_dl_entity *dl_se = &p->dl;
+
+	attr->sched_priority = p->rt_priority;
+	attr->sched_runtime = dl_se->dl_runtime;
+	attr->sched_deadline = dl_se->dl_deadline;
+	attr->sched_period = dl_se->dl_period;
+	attr->sched_flags &= ~SCHED_DL_FLAGS;
+	attr->sched_flags |= dl_se->flags;
+}
+
+/*
+ * This function validates the new parameters of a -deadline task.
+ * We ask for the deadline not being zero, and greater or equal
+ * than the runtime, as well as the period of being zero or
+ * greater than deadline. Furthermore, we have to be sure that
+ * user parameters are above the internal resolution of 1us (we
+ * check sched_runtime only since it is always the smaller one) and
+ * below 2^63 ns (we have to check both sched_deadline and
+ * sched_period, as the latter can be zero).
+ */
+bool __checkparam_dl(const struct sched_attr *attr)
+{
+	u64 period, max, min;
+
+	/* special dl tasks don't actually use any parameter */
+	if (attr->sched_flags & SCHED_FLAG_SUGOV)
+		return true;
+
+	/* deadline != 0 */
+	if (attr->sched_deadline == 0)
+		return false;
+
+	/*
+	 * Since we truncate DL_SCALE bits, make sure we're at least
+	 * that big.
+	 */
+	if (attr->sched_runtime < (1ULL << DL_SCALE))
+		return false;
+
+	/*
+	 * Since we use the MSB for wrap-around and sign issues, make
+	 * sure it's not set (mind that period can be equal to zero).
+	 */
+	if (attr->sched_deadline & (1ULL << 63) ||
+	    attr->sched_period & (1ULL << 63))
+		return false;
+
+	period = attr->sched_period;
+	if (!period)
+		period = attr->sched_deadline;
+
+	/* runtime <= deadline <= period (if period != 0) */
+	if (period < attr->sched_deadline ||
+	    attr->sched_deadline < attr->sched_runtime)
+		return false;
+
+	max = (u64)READ_ONCE(sysctl_sched_dl_period_max) * NSEC_PER_USEC;
+	min = (u64)READ_ONCE(sysctl_sched_dl_period_min) * NSEC_PER_USEC;
+
+	if (period < min || period > max)
+		return false;
+
+	return true;
+}
+
+/*
+ * This function clears the sched_dl_entity static params.
+ */
+void __dl_clear_params(struct task_struct *p)
+{
+	struct sched_dl_entity *dl_se = &p->dl;
+
+	dl_se->dl_runtime		= 0;
+	dl_se->dl_deadline		= 0;
+	dl_se->dl_period		= 0;
+	dl_se->flags			= 0;
+	dl_se->dl_bw			= 0;
+	dl_se->dl_density		= 0;
+
+	dl_se->dl_throttled		= 0;
+	dl_se->dl_yielded		= 0;
+	dl_se->dl_non_contending	= 0;
+	dl_se->dl_overrun		= 0;
+
+#ifdef CONFIG_RT_MUTEXES
+	dl_se->pi_se			= dl_se;
+#endif
+}
+
+bool dl_param_changed(struct task_struct *p, const struct sched_attr *attr)
+{
+	struct sched_dl_entity *dl_se = &p->dl;
+
+	if (dl_se->dl_runtime != attr->sched_runtime ||
+	    dl_se->dl_deadline != attr->sched_deadline ||
+	    dl_se->dl_period != attr->sched_period ||
+	    dl_se->flags != (attr->sched_flags & SCHED_DL_FLAGS))
+		return true;
+
+	return false;
+}
+
+#ifdef CONFIG_SMP
+int dl_cpuset_cpumask_can_shrink(const struct cpumask *cur,
+				 const struct cpumask *trial)
+{
+	unsigned long flags, cap;
+	struct dl_bw *cur_dl_b;
+	int ret = 1;
+
+	rcu_read_lock_sched();
+	cur_dl_b = dl_bw_of(cpumask_any(cur));
+	cap = __dl_bw_capacity(trial);
+	raw_spin_lock_irqsave(&cur_dl_b->lock, flags);
+	if (__dl_overflow(cur_dl_b, cap, 0, 0))
+		ret = 0;
+	raw_spin_unlock_irqrestore(&cur_dl_b->lock, flags);
+	rcu_read_unlock_sched();
+
+	return ret;
+}
+
+enum dl_bw_request {
+	dl_bw_req_check_overflow = 0,
+	dl_bw_req_alloc,
+	dl_bw_req_free
+};
+
+static int dl_bw_manage(enum dl_bw_request req, int cpu, u64 dl_bw)
+{
+	unsigned long flags;
+	struct dl_bw *dl_b;
+	bool overflow = 0;
+
+	rcu_read_lock_sched();
+	dl_b = dl_bw_of(cpu);
+	raw_spin_lock_irqsave(&dl_b->lock, flags);
+
+	if (req == dl_bw_req_free) {
+		__dl_sub(dl_b, dl_bw, dl_bw_cpus(cpu));
+	} else {
+		unsigned long cap = dl_bw_capacity(cpu);
+
+		overflow = __dl_overflow(dl_b, cap, 0, dl_bw);
+
+		if (req == dl_bw_req_alloc && !overflow) {
+			/*
+			 * We reserve space in the destination
+			 * root_domain, as we can't fail after this point.
+			 * We will free resources in the source root_domain
+			 * later on (see set_cpus_allowed_dl()).
+			 */
+			__dl_add(dl_b, dl_bw, dl_bw_cpus(cpu));
+		}
+	}
+
+	raw_spin_unlock_irqrestore(&dl_b->lock, flags);
+	rcu_read_unlock_sched();
+
+	return overflow ? -EBUSY : 0;
+}
+
+int dl_bw_check_overflow(int cpu)
+{
+	return dl_bw_manage(dl_bw_req_check_overflow, cpu, 0);
+}
+
+int dl_bw_alloc(int cpu, u64 dl_bw)
+{
+	return dl_bw_manage(dl_bw_req_alloc, cpu, dl_bw);
+}
+
+void dl_bw_free(int cpu, u64 dl_bw)
+{
+	dl_bw_manage(dl_bw_req_free, cpu, dl_bw);
+}
+#endif
+
+#ifdef CONFIG_SCHED_DEBUG
+void print_dl_stats(struct seq_file *m, int cpu)
+{
+	print_dl_rq(m, cpu, &cpu_rq(cpu)->dl);
+}
+#endif /* CONFIG_SCHED_DEBUG */
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
new file mode 100644
index 0000000000..4c3d0d9f3d
--- /dev/null
+++ b/kernel/sched/debug.c
@@ -0,0 +1,1123 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kernel/sched/debug.c
+ *
+ * Print the CFS rbtree and other debugging details
+ *
+ * Copyright(C) 2007, Red Hat, Inc., Ingo Molnar
+ */
+
+/*
+ * This allows printing both to /proc/sched_debug and
+ * to the console
+ */
+#define SEQ_printf(m, x...)			\
+ do {						\
+	if (m)					\
+		seq_printf(m, x);		\
+	else					\
+		pr_cont(x);			\
+ } while (0)
+
+/*
+ * Ease the printing of nsec fields:
+ */
+static long long nsec_high(unsigned long long nsec)
+{
+	if ((long long)nsec < 0) {
+		nsec = -nsec;
+		do_div(nsec, 1000000);
+		return -nsec;
+	}
+	do_div(nsec, 1000000);
+
+	return nsec;
+}
+
+static unsigned long nsec_low(unsigned long long nsec)
+{
+	if ((long long)nsec < 0)
+		nsec = -nsec;
+
+	return do_div(nsec, 1000000);
+}
+
+#define SPLIT_NS(x) nsec_high(x), nsec_low(x)
+
+#define SCHED_FEAT(name, enabled)	\
+	#name ,
+
+static const char * const sched_feat_names[] = {
+#include "features.h"
+};
+
+#undef SCHED_FEAT
+
+static int sched_feat_show(struct seq_file *m, void *v)
+{
+	int i;
+
+	for (i = 0; i < __SCHED_FEAT_NR; i++) {
+		if (!(sysctl_sched_features & (1UL << i)))
+			seq_puts(m, "NO_");
+		seq_printf(m, "%s ", sched_feat_names[i]);
+	}
+	seq_puts(m, "\n");
+
+	return 0;
+}
+
+#ifdef CONFIG_JUMP_LABEL
+
+#define jump_label_key__true  STATIC_KEY_INIT_TRUE
+#define jump_label_key__false STATIC_KEY_INIT_FALSE
+
+#define SCHED_FEAT(name, enabled)	\
+	jump_label_key__##enabled ,
+
+struct static_key sched_feat_keys[__SCHED_FEAT_NR] = {
+#include "features.h"
+};
+
+#undef SCHED_FEAT
+
+static void sched_feat_disable(int i)
+{
+	static_key_disable_cpuslocked(&sched_feat_keys[i]);
+}
+
+static void sched_feat_enable(int i)
+{
+	static_key_enable_cpuslocked(&sched_feat_keys[i]);
+}
+#else
+static void sched_feat_disable(int i) { };
+static void sched_feat_enable(int i) { };
+#endif /* CONFIG_JUMP_LABEL */
+
+static int sched_feat_set(char *cmp)
+{
+	int i;
+	int neg = 0;
+
+	if (strncmp(cmp, "NO_", 3) == 0) {
+		neg = 1;
+		cmp += 3;
+	}
+
+	i = match_string(sched_feat_names, __SCHED_FEAT_NR, cmp);
+	if (i < 0)
+		return i;
+
+	if (neg) {
+		sysctl_sched_features &= ~(1UL << i);
+		sched_feat_disable(i);
+	} else {
+		sysctl_sched_features |= (1UL << i);
+		sched_feat_enable(i);
+	}
+
+	return 0;
+}
+
+static ssize_t
+sched_feat_write(struct file *filp, const char __user *ubuf,
+		size_t cnt, loff_t *ppos)
+{
+	char buf[64];
+	char *cmp;
+	int ret;
+	struct inode *inode;
+
+	if (cnt > 63)
+		cnt = 63;
+
+	if (copy_from_user(&buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = 0;
+	cmp = strstrip(buf);
+
+	/* Ensure the static_key remains in a consistent state */
+	inode = file_inode(filp);
+	cpus_read_lock();
+	inode_lock(inode);
+	ret = sched_feat_set(cmp);
+	inode_unlock(inode);
+	cpus_read_unlock();
+	if (ret < 0)
+		return ret;
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static int sched_feat_open(struct inode *inode, struct file *filp)
+{
+	return single_open(filp, sched_feat_show, NULL);
+}
+
+static const struct file_operations sched_feat_fops = {
+	.open		= sched_feat_open,
+	.write		= sched_feat_write,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+#ifdef CONFIG_SMP
+
+static ssize_t sched_scaling_write(struct file *filp, const char __user *ubuf,
+				   size_t cnt, loff_t *ppos)
+{
+	char buf[16];
+	unsigned int scaling;
+
+	if (cnt > 15)
+		cnt = 15;
+
+	if (copy_from_user(&buf, ubuf, cnt))
+		return -EFAULT;
+	buf[cnt] = '\0';
+
+	if (kstrtouint(buf, 10, &scaling))
+		return -EINVAL;
+
+	if (scaling >= SCHED_TUNABLESCALING_END)
+		return -EINVAL;
+
+	sysctl_sched_tunable_scaling = scaling;
+	if (sched_update_scaling())
+		return -EINVAL;
+
+	*ppos += cnt;
+	return cnt;
+}
+
+static int sched_scaling_show(struct seq_file *m, void *v)
+{
+	seq_printf(m, "%d\n", sysctl_sched_tunable_scaling);
+	return 0;
+}
+
+static int sched_scaling_open(struct inode *inode, struct file *filp)
+{
+	return single_open(filp, sched_scaling_show, NULL);
+}
+
+static const struct file_operations sched_scaling_fops = {
+	.open		= sched_scaling_open,
+	.write		= sched_scaling_write,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+#endif /* SMP */
+
+#ifdef CONFIG_PREEMPT_DYNAMIC
+
+static ssize_t sched_dynamic_write(struct file *filp, const char __user *ubuf,
+				   size_t cnt, loff_t *ppos)
+{
+	char buf[16];
+	int mode;
+
+	if (cnt > 15)
+		cnt = 15;
+
+	if (copy_from_user(&buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = 0;
+	mode = sched_dynamic_mode(strstrip(buf));
+	if (mode < 0)
+		return mode;
+
+	sched_dynamic_update(mode);
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static int sched_dynamic_show(struct seq_file *m, void *v)
+{
+	static const char * preempt_modes[] = {
+		"none", "voluntary", "full"
+	};
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(preempt_modes); i++) {
+		if (preempt_dynamic_mode == i)
+			seq_puts(m, "(");
+		seq_puts(m, preempt_modes[i]);
+		if (preempt_dynamic_mode == i)
+			seq_puts(m, ")");
+
+		seq_puts(m, " ");
+	}
+
+	seq_puts(m, "\n");
+	return 0;
+}
+
+static int sched_dynamic_open(struct inode *inode, struct file *filp)
+{
+	return single_open(filp, sched_dynamic_show, NULL);
+}
+
+static const struct file_operations sched_dynamic_fops = {
+	.open		= sched_dynamic_open,
+	.write		= sched_dynamic_write,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+#endif /* CONFIG_PREEMPT_DYNAMIC */
+
+__read_mostly bool sched_debug_verbose;
+
+#ifdef CONFIG_SMP
+static struct dentry           *sd_dentry;
+
+
+static ssize_t sched_verbose_write(struct file *filp, const char __user *ubuf,
+				  size_t cnt, loff_t *ppos)
+{
+	ssize_t result;
+	bool orig;
+
+	cpus_read_lock();
+	mutex_lock(&sched_domains_mutex);
+
+	orig = sched_debug_verbose;
+	result = debugfs_write_file_bool(filp, ubuf, cnt, ppos);
+
+	if (sched_debug_verbose && !orig)
+		update_sched_domain_debugfs();
+	else if (!sched_debug_verbose && orig) {
+		debugfs_remove(sd_dentry);
+		sd_dentry = NULL;
+	}
+
+	mutex_unlock(&sched_domains_mutex);
+	cpus_read_unlock();
+
+	return result;
+}
+#else
+#define sched_verbose_write debugfs_write_file_bool
+#endif
+
+static const struct file_operations sched_verbose_fops = {
+	.read =         debugfs_read_file_bool,
+	.write =        sched_verbose_write,
+	.open =         simple_open,
+	.llseek =       default_llseek,
+};
+
+static const struct seq_operations sched_debug_sops;
+
+static int sched_debug_open(struct inode *inode, struct file *filp)
+{
+	return seq_open(filp, &sched_debug_sops);
+}
+
+static const struct file_operations sched_debug_fops = {
+	.open		= sched_debug_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+static struct dentry *debugfs_sched;
+
+static __init int sched_init_debug(void)
+{
+	struct dentry __maybe_unused *numa;
+
+	debugfs_sched = debugfs_create_dir("sched", NULL);
+
+	debugfs_create_file("features", 0644, debugfs_sched, NULL, &sched_feat_fops);
+	debugfs_create_file_unsafe("verbose", 0644, debugfs_sched, &sched_debug_verbose, &sched_verbose_fops);
+#ifdef CONFIG_PREEMPT_DYNAMIC
+	debugfs_create_file("preempt", 0644, debugfs_sched, NULL, &sched_dynamic_fops);
+#endif
+
+	debugfs_create_u32("base_slice_ns", 0644, debugfs_sched, &sysctl_sched_base_slice);
+
+	debugfs_create_u32("latency_warn_ms", 0644, debugfs_sched, &sysctl_resched_latency_warn_ms);
+	debugfs_create_u32("latency_warn_once", 0644, debugfs_sched, &sysctl_resched_latency_warn_once);
+
+#ifdef CONFIG_SMP
+	debugfs_create_file("tunable_scaling", 0644, debugfs_sched, NULL, &sched_scaling_fops);
+	debugfs_create_u32("migration_cost_ns", 0644, debugfs_sched, &sysctl_sched_migration_cost);
+	debugfs_create_u32("nr_migrate", 0644, debugfs_sched, &sysctl_sched_nr_migrate);
+
+	mutex_lock(&sched_domains_mutex);
+	update_sched_domain_debugfs();
+	mutex_unlock(&sched_domains_mutex);
+#endif
+
+#ifdef CONFIG_NUMA_BALANCING
+	numa = debugfs_create_dir("numa_balancing", debugfs_sched);
+
+	debugfs_create_u32("scan_delay_ms", 0644, numa, &sysctl_numa_balancing_scan_delay);
+	debugfs_create_u32("scan_period_min_ms", 0644, numa, &sysctl_numa_balancing_scan_period_min);
+	debugfs_create_u32("scan_period_max_ms", 0644, numa, &sysctl_numa_balancing_scan_period_max);
+	debugfs_create_u32("scan_size_mb", 0644, numa, &sysctl_numa_balancing_scan_size);
+	debugfs_create_u32("hot_threshold_ms", 0644, numa, &sysctl_numa_balancing_hot_threshold);
+#endif
+
+	debugfs_create_file("debug", 0444, debugfs_sched, NULL, &sched_debug_fops);
+
+	return 0;
+}
+late_initcall(sched_init_debug);
+
+#ifdef CONFIG_SMP
+
+static cpumask_var_t		sd_sysctl_cpus;
+
+static int sd_flags_show(struct seq_file *m, void *v)
+{
+	unsigned long flags = *(unsigned int *)m->private;
+	int idx;
+
+	for_each_set_bit(idx, &flags, __SD_FLAG_CNT) {
+		seq_puts(m, sd_flag_debug[idx].name);
+		seq_puts(m, " ");
+	}
+	seq_puts(m, "\n");
+
+	return 0;
+}
+
+static int sd_flags_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, sd_flags_show, inode->i_private);
+}
+
+static const struct file_operations sd_flags_fops = {
+	.open		= sd_flags_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static void register_sd(struct sched_domain *sd, struct dentry *parent)
+{
+#define SDM(type, mode, member)	\
+	debugfs_create_##type(#member, mode, parent, &sd->member)
+
+	SDM(ulong, 0644, min_interval);
+	SDM(ulong, 0644, max_interval);
+	SDM(u64,   0644, max_newidle_lb_cost);
+	SDM(u32,   0644, busy_factor);
+	SDM(u32,   0644, imbalance_pct);
+	SDM(u32,   0644, cache_nice_tries);
+	SDM(str,   0444, name);
+
+#undef SDM
+
+	debugfs_create_file("flags", 0444, parent, &sd->flags, &sd_flags_fops);
+	debugfs_create_file("groups_flags", 0444, parent, &sd->groups->flags, &sd_flags_fops);
+}
+
+void update_sched_domain_debugfs(void)
+{
+	int cpu, i;
+
+	/*
+	 * This can unfortunately be invoked before sched_debug_init() creates
+	 * the debug directory. Don't touch sd_sysctl_cpus until then.
+	 */
+	if (!debugfs_sched)
+		return;
+
+	if (!sched_debug_verbose)
+		return;
+
+	if (!cpumask_available(sd_sysctl_cpus)) {
+		if (!alloc_cpumask_var(&sd_sysctl_cpus, GFP_KERNEL))
+			return;
+		cpumask_copy(sd_sysctl_cpus, cpu_possible_mask);
+	}
+
+	if (!sd_dentry) {
+		sd_dentry = debugfs_create_dir("domains", debugfs_sched);
+
+		/* rebuild sd_sysctl_cpus if empty since it gets cleared below */
+		if (cpumask_empty(sd_sysctl_cpus))
+			cpumask_copy(sd_sysctl_cpus, cpu_online_mask);
+	}
+
+	for_each_cpu(cpu, sd_sysctl_cpus) {
+		struct sched_domain *sd;
+		struct dentry *d_cpu;
+		char buf[32];
+
+		snprintf(buf, sizeof(buf), "cpu%d", cpu);
+		debugfs_lookup_and_remove(buf, sd_dentry);
+		d_cpu = debugfs_create_dir(buf, sd_dentry);
+
+		i = 0;
+		for_each_domain(cpu, sd) {
+			struct dentry *d_sd;
+
+			snprintf(buf, sizeof(buf), "domain%d", i);
+			d_sd = debugfs_create_dir(buf, d_cpu);
+
+			register_sd(sd, d_sd);
+			i++;
+		}
+
+		__cpumask_clear_cpu(cpu, sd_sysctl_cpus);
+	}
+}
+
+void dirty_sched_domain_sysctl(int cpu)
+{
+	if (cpumask_available(sd_sysctl_cpus))
+		__cpumask_set_cpu(cpu, sd_sysctl_cpus);
+}
+
+#endif /* CONFIG_SMP */
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static void print_cfs_group_stats(struct seq_file *m, int cpu, struct task_group *tg)
+{
+	struct sched_entity *se = tg->se[cpu];
+
+#define P(F)		SEQ_printf(m, "  .%-30s: %lld\n",	#F, (long long)F)
+#define P_SCHEDSTAT(F)	SEQ_printf(m, "  .%-30s: %lld\n",	\
+		#F, (long long)schedstat_val(stats->F))
+#define PN(F)		SEQ_printf(m, "  .%-30s: %lld.%06ld\n", #F, SPLIT_NS((long long)F))
+#define PN_SCHEDSTAT(F)	SEQ_printf(m, "  .%-30s: %lld.%06ld\n", \
+		#F, SPLIT_NS((long long)schedstat_val(stats->F)))
+
+	if (!se)
+		return;
+
+	PN(se->exec_start);
+	PN(se->vruntime);
+	PN(se->sum_exec_runtime);
+
+	if (schedstat_enabled()) {
+		struct sched_statistics *stats;
+		stats = __schedstats_from_se(se);
+
+		PN_SCHEDSTAT(wait_start);
+		PN_SCHEDSTAT(sleep_start);
+		PN_SCHEDSTAT(block_start);
+		PN_SCHEDSTAT(sleep_max);
+		PN_SCHEDSTAT(block_max);
+		PN_SCHEDSTAT(exec_max);
+		PN_SCHEDSTAT(slice_max);
+		PN_SCHEDSTAT(wait_max);
+		PN_SCHEDSTAT(wait_sum);
+		P_SCHEDSTAT(wait_count);
+	}
+
+	P(se->load.weight);
+#ifdef CONFIG_SMP
+	P(se->avg.load_avg);
+	P(se->avg.util_avg);
+	P(se->avg.runnable_avg);
+#endif
+
+#undef PN_SCHEDSTAT
+#undef PN
+#undef P_SCHEDSTAT
+#undef P
+}
+#endif
+
+#ifdef CONFIG_CGROUP_SCHED
+static DEFINE_SPINLOCK(sched_debug_lock);
+static char group_path[PATH_MAX];
+
+static void task_group_path(struct task_group *tg, char *path, int plen)
+{
+	if (autogroup_path(tg, path, plen))
+		return;
+
+	cgroup_path(tg->css.cgroup, path, plen);
+}
+
+/*
+ * Only 1 SEQ_printf_task_group_path() caller can use the full length
+ * group_path[] for cgroup path. Other simultaneous callers will have
+ * to use a shorter stack buffer. A "..." suffix is appended at the end
+ * of the stack buffer so that it will show up in case the output length
+ * matches the given buffer size to indicate possible path name truncation.
+ */
+#define SEQ_printf_task_group_path(m, tg, fmt...)			\
+{									\
+	if (spin_trylock(&sched_debug_lock)) {				\
+		task_group_path(tg, group_path, sizeof(group_path));	\
+		SEQ_printf(m, fmt, group_path);				\
+		spin_unlock(&sched_debug_lock);				\
+	} else {							\
+		char buf[128];						\
+		char *bufend = buf + sizeof(buf) - 3;			\
+		task_group_path(tg, buf, bufend - buf);			\
+		strcpy(bufend - 1, "...");				\
+		SEQ_printf(m, fmt, buf);				\
+	}								\
+}
+#endif
+
+static void
+print_task(struct seq_file *m, struct rq *rq, struct task_struct *p)
+{
+	if (task_current(rq, p))
+		SEQ_printf(m, ">R");
+	else
+		SEQ_printf(m, " %c", task_state_to_char(p));
+
+	SEQ_printf(m, "%15s %5d %9Ld.%06ld %c %9Ld.%06ld %9Ld.%06ld %9Ld.%06ld %9Ld %5d ",
+		p->comm, task_pid_nr(p),
+		SPLIT_NS(p->se.vruntime),
+		entity_eligible(cfs_rq_of(&p->se), &p->se) ? 'E' : 'N',
+		SPLIT_NS(p->se.deadline),
+		SPLIT_NS(p->se.slice),
+		SPLIT_NS(p->se.sum_exec_runtime),
+		(long long)(p->nvcsw + p->nivcsw),
+		p->prio);
+
+	SEQ_printf(m, "%9lld.%06ld %9lld.%06ld %9lld.%06ld %9lld.%06ld",
+		SPLIT_NS(schedstat_val_or_zero(p->stats.wait_sum)),
+		SPLIT_NS(p->se.sum_exec_runtime),
+		SPLIT_NS(schedstat_val_or_zero(p->stats.sum_sleep_runtime)),
+		SPLIT_NS(schedstat_val_or_zero(p->stats.sum_block_runtime)));
+
+#ifdef CONFIG_NUMA_BALANCING
+	SEQ_printf(m, " %d %d", task_node(p), task_numa_group_id(p));
+#endif
+#ifdef CONFIG_CGROUP_SCHED
+	SEQ_printf_task_group_path(m, task_group(p), " %s")
+#endif
+
+	SEQ_printf(m, "\n");
+}
+
+static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu)
+{
+	struct task_struct *g, *p;
+
+	SEQ_printf(m, "\n");
+	SEQ_printf(m, "runnable tasks:\n");
+	SEQ_printf(m, " S            task   PID         tree-key  switches  prio"
+		   "     wait-time             sum-exec        sum-sleep\n");
+	SEQ_printf(m, "-------------------------------------------------------"
+		   "------------------------------------------------------\n");
+
+	rcu_read_lock();
+	for_each_process_thread(g, p) {
+		if (task_cpu(p) != rq_cpu)
+			continue;
+
+		print_task(m, rq, p);
+	}
+	rcu_read_unlock();
+}
+
+void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
+{
+	s64 left_vruntime = -1, min_vruntime, right_vruntime = -1, spread;
+	struct sched_entity *last, *first;
+	struct rq *rq = cpu_rq(cpu);
+	unsigned long flags;
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	SEQ_printf(m, "\n");
+	SEQ_printf_task_group_path(m, cfs_rq->tg, "cfs_rq[%d]:%s\n", cpu);
+#else
+	SEQ_printf(m, "\n");
+	SEQ_printf(m, "cfs_rq[%d]:\n", cpu);
+#endif
+	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "exec_clock",
+			SPLIT_NS(cfs_rq->exec_clock));
+
+	raw_spin_rq_lock_irqsave(rq, flags);
+	first = __pick_first_entity(cfs_rq);
+	if (first)
+		left_vruntime = first->vruntime;
+	last = __pick_last_entity(cfs_rq);
+	if (last)
+		right_vruntime = last->vruntime;
+	min_vruntime = cfs_rq->min_vruntime;
+	raw_spin_rq_unlock_irqrestore(rq, flags);
+
+	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "left_vruntime",
+			SPLIT_NS(left_vruntime));
+	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "min_vruntime",
+			SPLIT_NS(min_vruntime));
+	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "avg_vruntime",
+			SPLIT_NS(avg_vruntime(cfs_rq)));
+	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "right_vruntime",
+			SPLIT_NS(right_vruntime));
+	spread = right_vruntime - left_vruntime;
+	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "spread", SPLIT_NS(spread));
+	SEQ_printf(m, "  .%-30s: %d\n", "nr_spread_over",
+			cfs_rq->nr_spread_over);
+	SEQ_printf(m, "  .%-30s: %d\n", "nr_running", cfs_rq->nr_running);
+	SEQ_printf(m, "  .%-30s: %d\n", "h_nr_running", cfs_rq->h_nr_running);
+	SEQ_printf(m, "  .%-30s: %d\n", "idle_nr_running",
+			cfs_rq->idle_nr_running);
+	SEQ_printf(m, "  .%-30s: %d\n", "idle_h_nr_running",
+			cfs_rq->idle_h_nr_running);
+	SEQ_printf(m, "  .%-30s: %ld\n", "load", cfs_rq->load.weight);
+#ifdef CONFIG_SMP
+	SEQ_printf(m, "  .%-30s: %lu\n", "load_avg",
+			cfs_rq->avg.load_avg);
+	SEQ_printf(m, "  .%-30s: %lu\n", "runnable_avg",
+			cfs_rq->avg.runnable_avg);
+	SEQ_printf(m, "  .%-30s: %lu\n", "util_avg",
+			cfs_rq->avg.util_avg);
+	SEQ_printf(m, "  .%-30s: %u\n", "util_est_enqueued",
+			cfs_rq->avg.util_est.enqueued);
+	SEQ_printf(m, "  .%-30s: %ld\n", "removed.load_avg",
+			cfs_rq->removed.load_avg);
+	SEQ_printf(m, "  .%-30s: %ld\n", "removed.util_avg",
+			cfs_rq->removed.util_avg);
+	SEQ_printf(m, "  .%-30s: %ld\n", "removed.runnable_avg",
+			cfs_rq->removed.runnable_avg);
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	SEQ_printf(m, "  .%-30s: %lu\n", "tg_load_avg_contrib",
+			cfs_rq->tg_load_avg_contrib);
+	SEQ_printf(m, "  .%-30s: %ld\n", "tg_load_avg",
+			atomic_long_read(&cfs_rq->tg->load_avg));
+#endif
+#endif
+#ifdef CONFIG_CFS_BANDWIDTH
+	SEQ_printf(m, "  .%-30s: %d\n", "throttled",
+			cfs_rq->throttled);
+	SEQ_printf(m, "  .%-30s: %d\n", "throttle_count",
+			cfs_rq->throttle_count);
+#endif
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	print_cfs_group_stats(m, cpu, cfs_rq->tg);
+#endif
+}
+
+void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq)
+{
+#ifdef CONFIG_RT_GROUP_SCHED
+	SEQ_printf(m, "\n");
+	SEQ_printf_task_group_path(m, rt_rq->tg, "rt_rq[%d]:%s\n", cpu);
+#else
+	SEQ_printf(m, "\n");
+	SEQ_printf(m, "rt_rq[%d]:\n", cpu);
+#endif
+
+#define P(x) \
+	SEQ_printf(m, "  .%-30s: %Ld\n", #x, (long long)(rt_rq->x))
+#define PU(x) \
+	SEQ_printf(m, "  .%-30s: %lu\n", #x, (unsigned long)(rt_rq->x))
+#define PN(x) \
+	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", #x, SPLIT_NS(rt_rq->x))
+
+	PU(rt_nr_running);
+#ifdef CONFIG_SMP
+	PU(rt_nr_migratory);
+#endif
+	P(rt_throttled);
+	PN(rt_time);
+	PN(rt_runtime);
+
+#undef PN
+#undef PU
+#undef P
+}
+
+void print_dl_rq(struct seq_file *m, int cpu, struct dl_rq *dl_rq)
+{
+	struct dl_bw *dl_bw;
+
+	SEQ_printf(m, "\n");
+	SEQ_printf(m, "dl_rq[%d]:\n", cpu);
+
+#define PU(x) \
+	SEQ_printf(m, "  .%-30s: %lu\n", #x, (unsigned long)(dl_rq->x))
+
+	PU(dl_nr_running);
+#ifdef CONFIG_SMP
+	PU(dl_nr_migratory);
+	dl_bw = &cpu_rq(cpu)->rd->dl_bw;
+#else
+	dl_bw = &dl_rq->dl_bw;
+#endif
+	SEQ_printf(m, "  .%-30s: %lld\n", "dl_bw->bw", dl_bw->bw);
+	SEQ_printf(m, "  .%-30s: %lld\n", "dl_bw->total_bw", dl_bw->total_bw);
+
+#undef PU
+}
+
+static void print_cpu(struct seq_file *m, int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+#ifdef CONFIG_X86
+	{
+		unsigned int freq = cpu_khz ? : 1;
+
+		SEQ_printf(m, "cpu#%d, %u.%03u MHz\n",
+			   cpu, freq / 1000, (freq % 1000));
+	}
+#else
+	SEQ_printf(m, "cpu#%d\n", cpu);
+#endif
+
+#define P(x)								\
+do {									\
+	if (sizeof(rq->x) == 4)						\
+		SEQ_printf(m, "  .%-30s: %d\n", #x, (int)(rq->x));	\
+	else								\
+		SEQ_printf(m, "  .%-30s: %Ld\n", #x, (long long)(rq->x));\
+} while (0)
+
+#define PN(x) \
+	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", #x, SPLIT_NS(rq->x))
+
+	P(nr_running);
+	P(nr_switches);
+	P(nr_uninterruptible);
+	PN(next_balance);
+	SEQ_printf(m, "  .%-30s: %ld\n", "curr->pid", (long)(task_pid_nr(rq->curr)));
+	PN(clock);
+	PN(clock_task);
+#undef P
+#undef PN
+
+#ifdef CONFIG_SMP
+#define P64(n) SEQ_printf(m, "  .%-30s: %Ld\n", #n, rq->n);
+	P64(avg_idle);
+	P64(max_idle_balance_cost);
+#undef P64
+#endif
+
+#define P(n) SEQ_printf(m, "  .%-30s: %d\n", #n, schedstat_val(rq->n));
+	if (schedstat_enabled()) {
+		P(yld_count);
+		P(sched_count);
+		P(sched_goidle);
+		P(ttwu_count);
+		P(ttwu_local);
+	}
+#undef P
+
+	print_cfs_stats(m, cpu);
+	print_rt_stats(m, cpu);
+	print_dl_stats(m, cpu);
+
+	print_rq(m, rq, cpu);
+	SEQ_printf(m, "\n");
+}
+
+static const char *sched_tunable_scaling_names[] = {
+	"none",
+	"logarithmic",
+	"linear"
+};
+
+static void sched_debug_header(struct seq_file *m)
+{
+	u64 ktime, sched_clk, cpu_clk;
+	unsigned long flags;
+
+	local_irq_save(flags);
+	ktime = ktime_to_ns(ktime_get());
+	sched_clk = sched_clock();
+	cpu_clk = local_clock();
+	local_irq_restore(flags);
+
+	SEQ_printf(m, "Sched Debug Version: v0.11, %s %.*s\n",
+		init_utsname()->release,
+		(int)strcspn(init_utsname()->version, " "),
+		init_utsname()->version);
+
+#define P(x) \
+	SEQ_printf(m, "%-40s: %Ld\n", #x, (long long)(x))
+#define PN(x) \
+	SEQ_printf(m, "%-40s: %Ld.%06ld\n", #x, SPLIT_NS(x))
+	PN(ktime);
+	PN(sched_clk);
+	PN(cpu_clk);
+	P(jiffies);
+#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
+	P(sched_clock_stable());
+#endif
+#undef PN
+#undef P
+
+	SEQ_printf(m, "\n");
+	SEQ_printf(m, "sysctl_sched\n");
+
+#define P(x) \
+	SEQ_printf(m, "  .%-40s: %Ld\n", #x, (long long)(x))
+#define PN(x) \
+	SEQ_printf(m, "  .%-40s: %Ld.%06ld\n", #x, SPLIT_NS(x))
+	PN(sysctl_sched_base_slice);
+	P(sysctl_sched_child_runs_first);
+	P(sysctl_sched_features);
+#undef PN
+#undef P
+
+	SEQ_printf(m, "  .%-40s: %d (%s)\n",
+		"sysctl_sched_tunable_scaling",
+		sysctl_sched_tunable_scaling,
+		sched_tunable_scaling_names[sysctl_sched_tunable_scaling]);
+	SEQ_printf(m, "\n");
+}
+
+static int sched_debug_show(struct seq_file *m, void *v)
+{
+	int cpu = (unsigned long)(v - 2);
+
+	if (cpu != -1)
+		print_cpu(m, cpu);
+	else
+		sched_debug_header(m);
+
+	return 0;
+}
+
+void sysrq_sched_debug_show(void)
+{
+	int cpu;
+
+	sched_debug_header(NULL);
+	for_each_online_cpu(cpu) {
+		/*
+		 * Need to reset softlockup watchdogs on all CPUs, because
+		 * another CPU might be blocked waiting for us to process
+		 * an IPI or stop_machine.
+		 */
+		touch_nmi_watchdog();
+		touch_all_softlockup_watchdogs();
+		print_cpu(NULL, cpu);
+	}
+}
+
+/*
+ * This iterator needs some explanation.
+ * It returns 1 for the header position.
+ * This means 2 is CPU 0.
+ * In a hotplugged system some CPUs, including CPU 0, may be missing so we have
+ * to use cpumask_* to iterate over the CPUs.
+ */
+static void *sched_debug_start(struct seq_file *file, loff_t *offset)
+{
+	unsigned long n = *offset;
+
+	if (n == 0)
+		return (void *) 1;
+
+	n--;
+
+	if (n > 0)
+		n = cpumask_next(n - 1, cpu_online_mask);
+	else
+		n = cpumask_first(cpu_online_mask);
+
+	*offset = n + 1;
+
+	if (n < nr_cpu_ids)
+		return (void *)(unsigned long)(n + 2);
+
+	return NULL;
+}
+
+static void *sched_debug_next(struct seq_file *file, void *data, loff_t *offset)
+{
+	(*offset)++;
+	return sched_debug_start(file, offset);
+}
+
+static void sched_debug_stop(struct seq_file *file, void *data)
+{
+}
+
+static const struct seq_operations sched_debug_sops = {
+	.start		= sched_debug_start,
+	.next		= sched_debug_next,
+	.stop		= sched_debug_stop,
+	.show		= sched_debug_show,
+};
+
+#define __PS(S, F) SEQ_printf(m, "%-45s:%21Ld\n", S, (long long)(F))
+#define __P(F) __PS(#F, F)
+#define   P(F) __PS(#F, p->F)
+#define   PM(F, M) __PS(#F, p->F & (M))
+#define __PSN(S, F) SEQ_printf(m, "%-45s:%14Ld.%06ld\n", S, SPLIT_NS((long long)(F)))
+#define __PN(F) __PSN(#F, F)
+#define   PN(F) __PSN(#F, p->F)
+
+
+#ifdef CONFIG_NUMA_BALANCING
+void print_numa_stats(struct seq_file *m, int node, unsigned long tsf,
+		unsigned long tpf, unsigned long gsf, unsigned long gpf)
+{
+	SEQ_printf(m, "numa_faults node=%d ", node);
+	SEQ_printf(m, "task_private=%lu task_shared=%lu ", tpf, tsf);
+	SEQ_printf(m, "group_private=%lu group_shared=%lu\n", gpf, gsf);
+}
+#endif
+
+
+static void sched_show_numa(struct task_struct *p, struct seq_file *m)
+{
+#ifdef CONFIG_NUMA_BALANCING
+	if (p->mm)
+		P(mm->numa_scan_seq);
+
+	P(numa_pages_migrated);
+	P(numa_preferred_nid);
+	P(total_numa_faults);
+	SEQ_printf(m, "current_node=%d, numa_group_id=%d\n",
+			task_node(p), task_numa_group_id(p));
+	show_numa_stats(p, m);
+#endif
+}
+
+void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns,
+						  struct seq_file *m)
+{
+	unsigned long nr_switches;
+
+	SEQ_printf(m, "%s (%d, #threads: %d)\n", p->comm, task_pid_nr_ns(p, ns),
+						get_nr_threads(p));
+	SEQ_printf(m,
+		"---------------------------------------------------------"
+		"----------\n");
+
+#define P_SCHEDSTAT(F)  __PS(#F, schedstat_val(p->stats.F))
+#define PN_SCHEDSTAT(F) __PSN(#F, schedstat_val(p->stats.F))
+
+	PN(se.exec_start);
+	PN(se.vruntime);
+	PN(se.sum_exec_runtime);
+
+	nr_switches = p->nvcsw + p->nivcsw;
+
+	P(se.nr_migrations);
+
+	if (schedstat_enabled()) {
+		u64 avg_atom, avg_per_cpu;
+
+		PN_SCHEDSTAT(sum_sleep_runtime);
+		PN_SCHEDSTAT(sum_block_runtime);
+		PN_SCHEDSTAT(wait_start);
+		PN_SCHEDSTAT(sleep_start);
+		PN_SCHEDSTAT(block_start);
+		PN_SCHEDSTAT(sleep_max);
+		PN_SCHEDSTAT(block_max);
+		PN_SCHEDSTAT(exec_max);
+		PN_SCHEDSTAT(slice_max);
+		PN_SCHEDSTAT(wait_max);
+		PN_SCHEDSTAT(wait_sum);
+		P_SCHEDSTAT(wait_count);
+		PN_SCHEDSTAT(iowait_sum);
+		P_SCHEDSTAT(iowait_count);
+		P_SCHEDSTAT(nr_migrations_cold);
+		P_SCHEDSTAT(nr_failed_migrations_affine);
+		P_SCHEDSTAT(nr_failed_migrations_running);
+		P_SCHEDSTAT(nr_failed_migrations_hot);
+		P_SCHEDSTAT(nr_forced_migrations);
+		P_SCHEDSTAT(nr_wakeups);
+		P_SCHEDSTAT(nr_wakeups_sync);
+		P_SCHEDSTAT(nr_wakeups_migrate);
+		P_SCHEDSTAT(nr_wakeups_local);
+		P_SCHEDSTAT(nr_wakeups_remote);
+		P_SCHEDSTAT(nr_wakeups_affine);
+		P_SCHEDSTAT(nr_wakeups_affine_attempts);
+		P_SCHEDSTAT(nr_wakeups_passive);
+		P_SCHEDSTAT(nr_wakeups_idle);
+
+		avg_atom = p->se.sum_exec_runtime;
+		if (nr_switches)
+			avg_atom = div64_ul(avg_atom, nr_switches);
+		else
+			avg_atom = -1LL;
+
+		avg_per_cpu = p->se.sum_exec_runtime;
+		if (p->se.nr_migrations) {
+			avg_per_cpu = div64_u64(avg_per_cpu,
+						p->se.nr_migrations);
+		} else {
+			avg_per_cpu = -1LL;
+		}
+
+		__PN(avg_atom);
+		__PN(avg_per_cpu);
+
+#ifdef CONFIG_SCHED_CORE
+		PN_SCHEDSTAT(core_forceidle_sum);
+#endif
+	}
+
+	__P(nr_switches);
+	__PS("nr_voluntary_switches", p->nvcsw);
+	__PS("nr_involuntary_switches", p->nivcsw);
+
+	P(se.load.weight);
+#ifdef CONFIG_SMP
+	P(se.avg.load_sum);
+	P(se.avg.runnable_sum);
+	P(se.avg.util_sum);
+	P(se.avg.load_avg);
+	P(se.avg.runnable_avg);
+	P(se.avg.util_avg);
+	P(se.avg.last_update_time);
+	P(se.avg.util_est.ewma);
+	PM(se.avg.util_est.enqueued, ~UTIL_AVG_UNCHANGED);
+#endif
+#ifdef CONFIG_UCLAMP_TASK
+	__PS("uclamp.min", p->uclamp_req[UCLAMP_MIN].value);
+	__PS("uclamp.max", p->uclamp_req[UCLAMP_MAX].value);
+	__PS("effective uclamp.min", uclamp_eff_value(p, UCLAMP_MIN));
+	__PS("effective uclamp.max", uclamp_eff_value(p, UCLAMP_MAX));
+#endif
+	P(policy);
+	P(prio);
+	if (task_has_dl_policy(p)) {
+		P(dl.runtime);
+		P(dl.deadline);
+	}
+#undef PN_SCHEDSTAT
+#undef P_SCHEDSTAT
+
+	{
+		unsigned int this_cpu = raw_smp_processor_id();
+		u64 t0, t1;
+
+		t0 = cpu_clock(this_cpu);
+		t1 = cpu_clock(this_cpu);
+		__PS("clock-delta", t1-t0);
+	}
+
+	sched_show_numa(p, m);
+}
+
+void proc_sched_set_task(struct task_struct *p)
+{
+#ifdef CONFIG_SCHEDSTATS
+	memset(&p->stats, 0, sizeof(p->stats));
+#endif
+}
+
+void resched_latency_warn(int cpu, u64 latency)
+{
+	static DEFINE_RATELIMIT_STATE(latency_check_ratelimit, 60 * 60 * HZ, 1);
+
+	WARN(__ratelimit(&latency_check_ratelimit),
+	     "sched: CPU %d need_resched set for > %llu ns (%d ticks) "
+	     "without schedule\n",
+	     cpu, latency, cpu_rq(cpu)->ticks_without_resched);
+}
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
new file mode 100644
index 0000000000..d336af9cba
--- /dev/null
+++ b/kernel/sched/fair.c
@@ -0,0 +1,13110 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Completely Fair Scheduling (CFS) Class (SCHED_NORMAL/SCHED_BATCH)
+ *
+ *  Copyright (C) 2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ *  Interactivity improvements by Mike Galbraith
+ *  (C) 2007 Mike Galbraith <efault@gmx.de>
+ *
+ *  Various enhancements by Dmitry Adamushko.
+ *  (C) 2007 Dmitry Adamushko <dmitry.adamushko@gmail.com>
+ *
+ *  Group scheduling enhancements by Srivatsa Vaddagiri
+ *  Copyright IBM Corporation, 2007
+ *  Author: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
+ *
+ *  Scaled math optimizations by Thomas Gleixner
+ *  Copyright (C) 2007, Thomas Gleixner <tglx@linutronix.de>
+ *
+ *  Adaptive scheduling granularity, math enhancements by Peter Zijlstra
+ *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
+ */
+#include <linux/energy_model.h>
+#include <linux/mmap_lock.h>
+#include <linux/hugetlb_inline.h>
+#include <linux/jiffies.h>
+#include <linux/mm_api.h>
+#include <linux/highmem.h>
+#include <linux/spinlock_api.h>
+#include <linux/cpumask_api.h>
+#include <linux/lockdep_api.h>
+#include <linux/softirq.h>
+#include <linux/refcount_api.h>
+#include <linux/topology.h>
+#include <linux/sched/clock.h>
+#include <linux/sched/cond_resched.h>
+#include <linux/sched/cputime.h>
+#include <linux/sched/isolation.h>
+#include <linux/sched/nohz.h>
+
+#include <linux/cpuidle.h>
+#include <linux/interrupt.h>
+#include <linux/memory-tiers.h>
+#include <linux/mempolicy.h>
+#include <linux/mutex_api.h>
+#include <linux/profile.h>
+#include <linux/psi.h>
+#include <linux/ratelimit.h>
+#include <linux/task_work.h>
+#include <linux/rbtree_augmented.h>
+
+#include <asm/switch_to.h>
+
+#include <linux/sched/cond_resched.h>
+
+#include "sched.h"
+#include "stats.h"
+#include "autogroup.h"
+
+/*
+ * The initial- and re-scaling of tunables is configurable
+ *
+ * Options are:
+ *
+ *   SCHED_TUNABLESCALING_NONE - unscaled, always *1
+ *   SCHED_TUNABLESCALING_LOG - scaled logarithmical, *1+ilog(ncpus)
+ *   SCHED_TUNABLESCALING_LINEAR - scaled linear, *ncpus
+ *
+ * (default SCHED_TUNABLESCALING_LOG = *(1+ilog(ncpus))
+ */
+unsigned int sysctl_sched_tunable_scaling = SCHED_TUNABLESCALING_LOG;
+
+/*
+ * Minimal preemption granularity for CPU-bound tasks:
+ *
+ * (default: 0.75 msec * (1 + ilog(ncpus)), units: nanoseconds)
+ */
+unsigned int sysctl_sched_base_slice			= 750000ULL;
+static unsigned int normalized_sysctl_sched_base_slice	= 750000ULL;
+
+/*
+ * After fork, child runs first. If set to 0 (default) then
+ * parent will (try to) run first.
+ */
+unsigned int sysctl_sched_child_runs_first __read_mostly;
+
+const_debug unsigned int sysctl_sched_migration_cost	= 500000UL;
+
+int sched_thermal_decay_shift;
+static int __init setup_sched_thermal_decay_shift(char *str)
+{
+	int _shift = 0;
+
+	if (kstrtoint(str, 0, &_shift))
+		pr_warn("Unable to set scheduler thermal pressure decay shift parameter\n");
+
+	sched_thermal_decay_shift = clamp(_shift, 0, 10);
+	return 1;
+}
+__setup("sched_thermal_decay_shift=", setup_sched_thermal_decay_shift);
+
+#ifdef CONFIG_SMP
+/*
+ * For asym packing, by default the lower numbered CPU has higher priority.
+ */
+int __weak arch_asym_cpu_priority(int cpu)
+{
+	return -cpu;
+}
+
+/*
+ * The margin used when comparing utilization with CPU capacity.
+ *
+ * (default: ~20%)
+ */
+#define fits_capacity(cap, max)	((cap) * 1280 < (max) * 1024)
+
+/*
+ * The margin used when comparing CPU capacities.
+ * is 'cap1' noticeably greater than 'cap2'
+ *
+ * (default: ~5%)
+ */
+#define capacity_greater(cap1, cap2) ((cap1) * 1024 > (cap2) * 1078)
+#endif
+
+#ifdef CONFIG_CFS_BANDWIDTH
+/*
+ * Amount of runtime to allocate from global (tg) to local (per-cfs_rq) pool
+ * each time a cfs_rq requests quota.
+ *
+ * Note: in the case that the slice exceeds the runtime remaining (either due
+ * to consumption or the quota being specified to be smaller than the slice)
+ * we will always only issue the remaining available time.
+ *
+ * (default: 5 msec, units: microseconds)
+ */
+static unsigned int sysctl_sched_cfs_bandwidth_slice		= 5000UL;
+#endif
+
+#ifdef CONFIG_NUMA_BALANCING
+/* Restrict the NUMA promotion throughput (MB/s) for each target node. */
+static unsigned int sysctl_numa_balancing_promote_rate_limit = 65536;
+#endif
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table sched_fair_sysctls[] = {
+	{
+		.procname       = "sched_child_runs_first",
+		.data           = &sysctl_sched_child_runs_first,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = proc_dointvec,
+	},
+#ifdef CONFIG_CFS_BANDWIDTH
+	{
+		.procname       = "sched_cfs_bandwidth_slice_us",
+		.data           = &sysctl_sched_cfs_bandwidth_slice,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = proc_dointvec_minmax,
+		.extra1         = SYSCTL_ONE,
+	},
+#endif
+#ifdef CONFIG_NUMA_BALANCING
+	{
+		.procname	= "numa_balancing_promote_rate_limit_MBps",
+		.data		= &sysctl_numa_balancing_promote_rate_limit,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+	},
+#endif /* CONFIG_NUMA_BALANCING */
+	{}
+};
+
+static int __init sched_fair_sysctl_init(void)
+{
+	register_sysctl_init("kernel", sched_fair_sysctls);
+	return 0;
+}
+late_initcall(sched_fair_sysctl_init);
+#endif
+
+static inline void update_load_add(struct load_weight *lw, unsigned long inc)
+{
+	lw->weight += inc;
+	lw->inv_weight = 0;
+}
+
+static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
+{
+	lw->weight -= dec;
+	lw->inv_weight = 0;
+}
+
+static inline void update_load_set(struct load_weight *lw, unsigned long w)
+{
+	lw->weight = w;
+	lw->inv_weight = 0;
+}
+
+/*
+ * Increase the granularity value when there are more CPUs,
+ * because with more CPUs the 'effective latency' as visible
+ * to users decreases. But the relationship is not linear,
+ * so pick a second-best guess by going with the log2 of the
+ * number of CPUs.
+ *
+ * This idea comes from the SD scheduler of Con Kolivas:
+ */
+static unsigned int get_update_sysctl_factor(void)
+{
+	unsigned int cpus = min_t(unsigned int, num_online_cpus(), 8);
+	unsigned int factor;
+
+	switch (sysctl_sched_tunable_scaling) {
+	case SCHED_TUNABLESCALING_NONE:
+		factor = 1;
+		break;
+	case SCHED_TUNABLESCALING_LINEAR:
+		factor = cpus;
+		break;
+	case SCHED_TUNABLESCALING_LOG:
+	default:
+		factor = 1 + ilog2(cpus);
+		break;
+	}
+
+	return factor;
+}
+
+static void update_sysctl(void)
+{
+	unsigned int factor = get_update_sysctl_factor();
+
+#define SET_SYSCTL(name) \
+	(sysctl_##name = (factor) * normalized_sysctl_##name)
+	SET_SYSCTL(sched_base_slice);
+#undef SET_SYSCTL
+}
+
+void __init sched_init_granularity(void)
+{
+	update_sysctl();
+}
+
+#define WMULT_CONST	(~0U)
+#define WMULT_SHIFT	32
+
+static void __update_inv_weight(struct load_weight *lw)
+{
+	unsigned long w;
+
+	if (likely(lw->inv_weight))
+		return;
+
+	w = scale_load_down(lw->weight);
+
+	if (BITS_PER_LONG > 32 && unlikely(w >= WMULT_CONST))
+		lw->inv_weight = 1;
+	else if (unlikely(!w))
+		lw->inv_weight = WMULT_CONST;
+	else
+		lw->inv_weight = WMULT_CONST / w;
+}
+
+/*
+ * delta_exec * weight / lw.weight
+ *   OR
+ * (delta_exec * (weight * lw->inv_weight)) >> WMULT_SHIFT
+ *
+ * Either weight := NICE_0_LOAD and lw \e sched_prio_to_wmult[], in which case
+ * we're guaranteed shift stays positive because inv_weight is guaranteed to
+ * fit 32 bits, and NICE_0_LOAD gives another 10 bits; therefore shift >= 22.
+ *
+ * Or, weight =< lw.weight (because lw.weight is the runqueue weight), thus
+ * weight/lw.weight <= 1, and therefore our shift will also be positive.
+ */
+static u64 __calc_delta(u64 delta_exec, unsigned long weight, struct load_weight *lw)
+{
+	u64 fact = scale_load_down(weight);
+	u32 fact_hi = (u32)(fact >> 32);
+	int shift = WMULT_SHIFT;
+	int fs;
+
+	__update_inv_weight(lw);
+
+	if (unlikely(fact_hi)) {
+		fs = fls(fact_hi);
+		shift -= fs;
+		fact >>= fs;
+	}
+
+	fact = mul_u32_u32(fact, lw->inv_weight);
+
+	fact_hi = (u32)(fact >> 32);
+	if (fact_hi) {
+		fs = fls(fact_hi);
+		shift -= fs;
+		fact >>= fs;
+	}
+
+	return mul_u64_u32_shr(delta_exec, fact, shift);
+}
+
+/*
+ * delta /= w
+ */
+static inline u64 calc_delta_fair(u64 delta, struct sched_entity *se)
+{
+	if (unlikely(se->load.weight != NICE_0_LOAD))
+		delta = __calc_delta(delta, NICE_0_LOAD, &se->load);
+
+	return delta;
+}
+
+const struct sched_class fair_sched_class;
+
+/**************************************************************
+ * CFS operations on generic schedulable entities:
+ */
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+
+/* Walk up scheduling entities hierarchy */
+#define for_each_sched_entity(se) \
+		for (; se; se = se->parent)
+
+static inline bool list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq)
+{
+	struct rq *rq = rq_of(cfs_rq);
+	int cpu = cpu_of(rq);
+
+	if (cfs_rq->on_list)
+		return rq->tmp_alone_branch == &rq->leaf_cfs_rq_list;
+
+	cfs_rq->on_list = 1;
+
+	/*
+	 * Ensure we either appear before our parent (if already
+	 * enqueued) or force our parent to appear after us when it is
+	 * enqueued. The fact that we always enqueue bottom-up
+	 * reduces this to two cases and a special case for the root
+	 * cfs_rq. Furthermore, it also means that we will always reset
+	 * tmp_alone_branch either when the branch is connected
+	 * to a tree or when we reach the top of the tree
+	 */
+	if (cfs_rq->tg->parent &&
+	    cfs_rq->tg->parent->cfs_rq[cpu]->on_list) {
+		/*
+		 * If parent is already on the list, we add the child
+		 * just before. Thanks to circular linked property of
+		 * the list, this means to put the child at the tail
+		 * of the list that starts by parent.
+		 */
+		list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list,
+			&(cfs_rq->tg->parent->cfs_rq[cpu]->leaf_cfs_rq_list));
+		/*
+		 * The branch is now connected to its tree so we can
+		 * reset tmp_alone_branch to the beginning of the
+		 * list.
+		 */
+		rq->tmp_alone_branch = &rq->leaf_cfs_rq_list;
+		return true;
+	}
+
+	if (!cfs_rq->tg->parent) {
+		/*
+		 * cfs rq without parent should be put
+		 * at the tail of the list.
+		 */
+		list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list,
+			&rq->leaf_cfs_rq_list);
+		/*
+		 * We have reach the top of a tree so we can reset
+		 * tmp_alone_branch to the beginning of the list.
+		 */
+		rq->tmp_alone_branch = &rq->leaf_cfs_rq_list;
+		return true;
+	}
+
+	/*
+	 * The parent has not already been added so we want to
+	 * make sure that it will be put after us.
+	 * tmp_alone_branch points to the begin of the branch
+	 * where we will add parent.
+	 */
+	list_add_rcu(&cfs_rq->leaf_cfs_rq_list, rq->tmp_alone_branch);
+	/*
+	 * update tmp_alone_branch to points to the new begin
+	 * of the branch
+	 */
+	rq->tmp_alone_branch = &cfs_rq->leaf_cfs_rq_list;
+	return false;
+}
+
+static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq)
+{
+	if (cfs_rq->on_list) {
+		struct rq *rq = rq_of(cfs_rq);
+
+		/*
+		 * With cfs_rq being unthrottled/throttled during an enqueue,
+		 * it can happen the tmp_alone_branch points the a leaf that
+		 * we finally want to del. In this case, tmp_alone_branch moves
+		 * to the prev element but it will point to rq->leaf_cfs_rq_list
+		 * at the end of the enqueue.
+		 */
+		if (rq->tmp_alone_branch == &cfs_rq->leaf_cfs_rq_list)
+			rq->tmp_alone_branch = cfs_rq->leaf_cfs_rq_list.prev;
+
+		list_del_rcu(&cfs_rq->leaf_cfs_rq_list);
+		cfs_rq->on_list = 0;
+	}
+}
+
+static inline void assert_list_leaf_cfs_rq(struct rq *rq)
+{
+	SCHED_WARN_ON(rq->tmp_alone_branch != &rq->leaf_cfs_rq_list);
+}
+
+/* Iterate thr' all leaf cfs_rq's on a runqueue */
+#define for_each_leaf_cfs_rq_safe(rq, cfs_rq, pos)			\
+	list_for_each_entry_safe(cfs_rq, pos, &rq->leaf_cfs_rq_list,	\
+				 leaf_cfs_rq_list)
+
+/* Do the two (enqueued) entities belong to the same group ? */
+static inline struct cfs_rq *
+is_same_group(struct sched_entity *se, struct sched_entity *pse)
+{
+	if (se->cfs_rq == pse->cfs_rq)
+		return se->cfs_rq;
+
+	return NULL;
+}
+
+static inline struct sched_entity *parent_entity(const struct sched_entity *se)
+{
+	return se->parent;
+}
+
+static void
+find_matching_se(struct sched_entity **se, struct sched_entity **pse)
+{
+	int se_depth, pse_depth;
+
+	/*
+	 * preemption test can be made between sibling entities who are in the
+	 * same cfs_rq i.e who have a common parent. Walk up the hierarchy of
+	 * both tasks until we find their ancestors who are siblings of common
+	 * parent.
+	 */
+
+	/* First walk up until both entities are at same depth */
+	se_depth = (*se)->depth;
+	pse_depth = (*pse)->depth;
+
+	while (se_depth > pse_depth) {
+		se_depth--;
+		*se = parent_entity(*se);
+	}
+
+	while (pse_depth > se_depth) {
+		pse_depth--;
+		*pse = parent_entity(*pse);
+	}
+
+	while (!is_same_group(*se, *pse)) {
+		*se = parent_entity(*se);
+		*pse = parent_entity(*pse);
+	}
+}
+
+static int tg_is_idle(struct task_group *tg)
+{
+	return tg->idle > 0;
+}
+
+static int cfs_rq_is_idle(struct cfs_rq *cfs_rq)
+{
+	return cfs_rq->idle > 0;
+}
+
+static int se_is_idle(struct sched_entity *se)
+{
+	if (entity_is_task(se))
+		return task_has_idle_policy(task_of(se));
+	return cfs_rq_is_idle(group_cfs_rq(se));
+}
+
+#else	/* !CONFIG_FAIR_GROUP_SCHED */
+
+#define for_each_sched_entity(se) \
+		for (; se; se = NULL)
+
+static inline bool list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq)
+{
+	return true;
+}
+
+static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq)
+{
+}
+
+static inline void assert_list_leaf_cfs_rq(struct rq *rq)
+{
+}
+
+#define for_each_leaf_cfs_rq_safe(rq, cfs_rq, pos)	\
+		for (cfs_rq = &rq->cfs, pos = NULL; cfs_rq; cfs_rq = pos)
+
+static inline struct sched_entity *parent_entity(struct sched_entity *se)
+{
+	return NULL;
+}
+
+static inline void
+find_matching_se(struct sched_entity **se, struct sched_entity **pse)
+{
+}
+
+static inline int tg_is_idle(struct task_group *tg)
+{
+	return 0;
+}
+
+static int cfs_rq_is_idle(struct cfs_rq *cfs_rq)
+{
+	return 0;
+}
+
+static int se_is_idle(struct sched_entity *se)
+{
+	return 0;
+}
+
+#endif	/* CONFIG_FAIR_GROUP_SCHED */
+
+static __always_inline
+void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec);
+
+/**************************************************************
+ * Scheduling class tree data structure manipulation methods:
+ */
+
+static inline u64 max_vruntime(u64 max_vruntime, u64 vruntime)
+{
+	s64 delta = (s64)(vruntime - max_vruntime);
+	if (delta > 0)
+		max_vruntime = vruntime;
+
+	return max_vruntime;
+}
+
+static inline u64 min_vruntime(u64 min_vruntime, u64 vruntime)
+{
+	s64 delta = (s64)(vruntime - min_vruntime);
+	if (delta < 0)
+		min_vruntime = vruntime;
+
+	return min_vruntime;
+}
+
+static inline bool entity_before(const struct sched_entity *a,
+				 const struct sched_entity *b)
+{
+	return (s64)(a->vruntime - b->vruntime) < 0;
+}
+
+static inline s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	return (s64)(se->vruntime - cfs_rq->min_vruntime);
+}
+
+#define __node_2_se(node) \
+	rb_entry((node), struct sched_entity, run_node)
+
+/*
+ * Compute virtual time from the per-task service numbers:
+ *
+ * Fair schedulers conserve lag:
+ *
+ *   \Sum lag_i = 0
+ *
+ * Where lag_i is given by:
+ *
+ *   lag_i = S - s_i = w_i * (V - v_i)
+ *
+ * Where S is the ideal service time and V is it's virtual time counterpart.
+ * Therefore:
+ *
+ *   \Sum lag_i = 0
+ *   \Sum w_i * (V - v_i) = 0
+ *   \Sum w_i * V - w_i * v_i = 0
+ *
+ * From which we can solve an expression for V in v_i (which we have in
+ * se->vruntime):
+ *
+ *       \Sum v_i * w_i   \Sum v_i * w_i
+ *   V = -------------- = --------------
+ *          \Sum w_i            W
+ *
+ * Specifically, this is the weighted average of all entity virtual runtimes.
+ *
+ * [[ NOTE: this is only equal to the ideal scheduler under the condition
+ *          that join/leave operations happen at lag_i = 0, otherwise the
+ *          virtual time has non-continguous motion equivalent to:
+ *
+ *	      V +-= lag_i / W
+ *
+ *	    Also see the comment in place_entity() that deals with this. ]]
+ *
+ * However, since v_i is u64, and the multiplcation could easily overflow
+ * transform it into a relative form that uses smaller quantities:
+ *
+ * Substitute: v_i == (v_i - v0) + v0
+ *
+ *     \Sum ((v_i - v0) + v0) * w_i   \Sum (v_i - v0) * w_i
+ * V = ---------------------------- = --------------------- + v0
+ *                  W                            W
+ *
+ * Which we track using:
+ *
+ *                    v0 := cfs_rq->min_vruntime
+ * \Sum (v_i - v0) * w_i := cfs_rq->avg_vruntime
+ *              \Sum w_i := cfs_rq->avg_load
+ *
+ * Since min_vruntime is a monotonic increasing variable that closely tracks
+ * the per-task service, these deltas: (v_i - v), will be in the order of the
+ * maximal (virtual) lag induced in the system due to quantisation.
+ *
+ * Also, we use scale_load_down() to reduce the size.
+ *
+ * As measured, the max (key * weight) value was ~44 bits for a kernel build.
+ */
+static void
+avg_vruntime_add(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	unsigned long weight = scale_load_down(se->load.weight);
+	s64 key = entity_key(cfs_rq, se);
+
+	cfs_rq->avg_vruntime += key * weight;
+	cfs_rq->avg_load += weight;
+}
+
+static void
+avg_vruntime_sub(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	unsigned long weight = scale_load_down(se->load.weight);
+	s64 key = entity_key(cfs_rq, se);
+
+	cfs_rq->avg_vruntime -= key * weight;
+	cfs_rq->avg_load -= weight;
+}
+
+static inline
+void avg_vruntime_update(struct cfs_rq *cfs_rq, s64 delta)
+{
+	/*
+	 * v' = v + d ==> avg_vruntime' = avg_runtime - d*avg_load
+	 */
+	cfs_rq->avg_vruntime -= cfs_rq->avg_load * delta;
+}
+
+/*
+ * Specifically: avg_runtime() + 0 must result in entity_eligible() := true
+ * For this to be so, the result of this function must have a left bias.
+ */
+u64 avg_vruntime(struct cfs_rq *cfs_rq)
+{
+	struct sched_entity *curr = cfs_rq->curr;
+	s64 avg = cfs_rq->avg_vruntime;
+	long load = cfs_rq->avg_load;
+
+	if (curr && curr->on_rq) {
+		unsigned long weight = scale_load_down(curr->load.weight);
+
+		avg += entity_key(cfs_rq, curr) * weight;
+		load += weight;
+	}
+
+	if (load) {
+		/* sign flips effective floor / ceil */
+		if (avg < 0)
+			avg -= (load - 1);
+		avg = div_s64(avg, load);
+	}
+
+	return cfs_rq->min_vruntime + avg;
+}
+
+/*
+ * lag_i = S - s_i = w_i * (V - v_i)
+ *
+ * However, since V is approximated by the weighted average of all entities it
+ * is possible -- by addition/removal/reweight to the tree -- to move V around
+ * and end up with a larger lag than we started with.
+ *
+ * Limit this to either double the slice length with a minimum of TICK_NSEC
+ * since that is the timing granularity.
+ *
+ * EEVDF gives the following limit for a steady state system:
+ *
+ *   -r_max < lag < max(r_max, q)
+ *
+ * XXX could add max_slice to the augmented data to track this.
+ */
+static void update_entity_lag(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	s64 lag, limit;
+
+	SCHED_WARN_ON(!se->on_rq);
+	lag = avg_vruntime(cfs_rq) - se->vruntime;
+
+	limit = calc_delta_fair(max_t(u64, 2*se->slice, TICK_NSEC), se);
+	se->vlag = clamp(lag, -limit, limit);
+}
+
+/*
+ * Entity is eligible once it received less service than it ought to have,
+ * eg. lag >= 0.
+ *
+ * lag_i = S - s_i = w_i*(V - v_i)
+ *
+ * lag_i >= 0 -> V >= v_i
+ *
+ *     \Sum (v_i - v)*w_i
+ * V = ------------------ + v
+ *          \Sum w_i
+ *
+ * lag_i >= 0 -> \Sum (v_i - v)*w_i >= (v_i - v)*(\Sum w_i)
+ *
+ * Note: using 'avg_vruntime() > se->vruntime' is inacurate due
+ *       to the loss in precision caused by the division.
+ */
+int entity_eligible(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	struct sched_entity *curr = cfs_rq->curr;
+	s64 avg = cfs_rq->avg_vruntime;
+	long load = cfs_rq->avg_load;
+
+	if (curr && curr->on_rq) {
+		unsigned long weight = scale_load_down(curr->load.weight);
+
+		avg += entity_key(cfs_rq, curr) * weight;
+		load += weight;
+	}
+
+	return avg >= entity_key(cfs_rq, se) * load;
+}
+
+static u64 __update_min_vruntime(struct cfs_rq *cfs_rq, u64 vruntime)
+{
+	u64 min_vruntime = cfs_rq->min_vruntime;
+	/*
+	 * open coded max_vruntime() to allow updating avg_vruntime
+	 */
+	s64 delta = (s64)(vruntime - min_vruntime);
+	if (delta > 0) {
+		avg_vruntime_update(cfs_rq, delta);
+		min_vruntime = vruntime;
+	}
+	return min_vruntime;
+}
+
+static void update_min_vruntime(struct cfs_rq *cfs_rq)
+{
+	struct sched_entity *se = __pick_first_entity(cfs_rq);
+	struct sched_entity *curr = cfs_rq->curr;
+
+	u64 vruntime = cfs_rq->min_vruntime;
+
+	if (curr) {
+		if (curr->on_rq)
+			vruntime = curr->vruntime;
+		else
+			curr = NULL;
+	}
+
+	if (se) {
+		if (!curr)
+			vruntime = se->vruntime;
+		else
+			vruntime = min_vruntime(vruntime, se->vruntime);
+	}
+
+	/* ensure we never gain time by being placed backwards. */
+	u64_u32_store(cfs_rq->min_vruntime,
+		      __update_min_vruntime(cfs_rq, vruntime));
+}
+
+static inline bool __entity_less(struct rb_node *a, const struct rb_node *b)
+{
+	return entity_before(__node_2_se(a), __node_2_se(b));
+}
+
+#define deadline_gt(field, lse, rse) ({ (s64)((lse)->field - (rse)->field) > 0; })
+
+static inline void __update_min_deadline(struct sched_entity *se, struct rb_node *node)
+{
+	if (node) {
+		struct sched_entity *rse = __node_2_se(node);
+		if (deadline_gt(min_deadline, se, rse))
+			se->min_deadline = rse->min_deadline;
+	}
+}
+
+/*
+ * se->min_deadline = min(se->deadline, left->min_deadline, right->min_deadline)
+ */
+static inline bool min_deadline_update(struct sched_entity *se, bool exit)
+{
+	u64 old_min_deadline = se->min_deadline;
+	struct rb_node *node = &se->run_node;
+
+	se->min_deadline = se->deadline;
+	__update_min_deadline(se, node->rb_right);
+	__update_min_deadline(se, node->rb_left);
+
+	return se->min_deadline == old_min_deadline;
+}
+
+RB_DECLARE_CALLBACKS(static, min_deadline_cb, struct sched_entity,
+		     run_node, min_deadline, min_deadline_update);
+
+/*
+ * Enqueue an entity into the rb-tree:
+ */
+static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	avg_vruntime_add(cfs_rq, se);
+	se->min_deadline = se->deadline;
+	rb_add_augmented_cached(&se->run_node, &cfs_rq->tasks_timeline,
+				__entity_less, &min_deadline_cb);
+}
+
+static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	rb_erase_augmented_cached(&se->run_node, &cfs_rq->tasks_timeline,
+				  &min_deadline_cb);
+	avg_vruntime_sub(cfs_rq, se);
+}
+
+struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq)
+{
+	struct rb_node *left = rb_first_cached(&cfs_rq->tasks_timeline);
+
+	if (!left)
+		return NULL;
+
+	return __node_2_se(left);
+}
+
+/*
+ * Earliest Eligible Virtual Deadline First
+ *
+ * In order to provide latency guarantees for different request sizes
+ * EEVDF selects the best runnable task from two criteria:
+ *
+ *  1) the task must be eligible (must be owed service)
+ *
+ *  2) from those tasks that meet 1), we select the one
+ *     with the earliest virtual deadline.
+ *
+ * We can do this in O(log n) time due to an augmented RB-tree. The
+ * tree keeps the entries sorted on service, but also functions as a
+ * heap based on the deadline by keeping:
+ *
+ *  se->min_deadline = min(se->deadline, se->{left,right}->min_deadline)
+ *
+ * Which allows an EDF like search on (sub)trees.
+ */
+static struct sched_entity *__pick_eevdf(struct cfs_rq *cfs_rq)
+{
+	struct rb_node *node = cfs_rq->tasks_timeline.rb_root.rb_node;
+	struct sched_entity *curr = cfs_rq->curr;
+	struct sched_entity *best = NULL;
+	struct sched_entity *best_left = NULL;
+
+	if (curr && (!curr->on_rq || !entity_eligible(cfs_rq, curr)))
+		curr = NULL;
+	best = curr;
+
+	/*
+	 * Once selected, run a task until it either becomes non-eligible or
+	 * until it gets a new slice. See the HACK in set_next_entity().
+	 */
+	if (sched_feat(RUN_TO_PARITY) && curr && curr->vlag == curr->deadline)
+		return curr;
+
+	while (node) {
+		struct sched_entity *se = __node_2_se(node);
+
+		/*
+		 * If this entity is not eligible, try the left subtree.
+		 */
+		if (!entity_eligible(cfs_rq, se)) {
+			node = node->rb_left;
+			continue;
+		}
+
+		/*
+		 * Now we heap search eligible trees for the best (min_)deadline
+		 */
+		if (!best || deadline_gt(deadline, best, se))
+			best = se;
+
+		/*
+		 * Every se in a left branch is eligible, keep track of the
+		 * branch with the best min_deadline
+		 */
+		if (node->rb_left) {
+			struct sched_entity *left = __node_2_se(node->rb_left);
+
+			if (!best_left || deadline_gt(min_deadline, best_left, left))
+				best_left = left;
+
+			/*
+			 * min_deadline is in the left branch. rb_left and all
+			 * descendants are eligible, so immediately switch to the second
+			 * loop.
+			 */
+			if (left->min_deadline == se->min_deadline)
+				break;
+		}
+
+		/* min_deadline is at this node, no need to look right */
+		if (se->deadline == se->min_deadline)
+			break;
+
+		/* else min_deadline is in the right branch. */
+		node = node->rb_right;
+	}
+
+	/*
+	 * We ran into an eligible node which is itself the best.
+	 * (Or nr_running == 0 and both are NULL)
+	 */
+	if (!best_left || (s64)(best_left->min_deadline - best->deadline) > 0)
+		return best;
+
+	/*
+	 * Now best_left and all of its children are eligible, and we are just
+	 * looking for deadline == min_deadline
+	 */
+	node = &best_left->run_node;
+	while (node) {
+		struct sched_entity *se = __node_2_se(node);
+
+		/* min_deadline is the current node */
+		if (se->deadline == se->min_deadline)
+			return se;
+
+		/* min_deadline is in the left branch */
+		if (node->rb_left &&
+		    __node_2_se(node->rb_left)->min_deadline == se->min_deadline) {
+			node = node->rb_left;
+			continue;
+		}
+
+		/* else min_deadline is in the right branch */
+		node = node->rb_right;
+	}
+	return NULL;
+}
+
+static struct sched_entity *pick_eevdf(struct cfs_rq *cfs_rq)
+{
+	struct sched_entity *se = __pick_eevdf(cfs_rq);
+
+	if (!se) {
+		struct sched_entity *left = __pick_first_entity(cfs_rq);
+		if (left) {
+			pr_err("EEVDF scheduling fail, picking leftmost\n");
+			return left;
+		}
+	}
+
+	return se;
+}
+
+#ifdef CONFIG_SCHED_DEBUG
+struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq)
+{
+	struct rb_node *last = rb_last(&cfs_rq->tasks_timeline.rb_root);
+
+	if (!last)
+		return NULL;
+
+	return __node_2_se(last);
+}
+
+/**************************************************************
+ * Scheduling class statistics methods:
+ */
+#ifdef CONFIG_SMP
+int sched_update_scaling(void)
+{
+	unsigned int factor = get_update_sysctl_factor();
+
+#define WRT_SYSCTL(name) \
+	(normalized_sysctl_##name = sysctl_##name / (factor))
+	WRT_SYSCTL(sched_base_slice);
+#undef WRT_SYSCTL
+
+	return 0;
+}
+#endif
+#endif
+
+static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se);
+
+/*
+ * XXX: strictly: vd_i += N*r_i/w_i such that: vd_i > ve_i
+ * this is probably good enough.
+ */
+static void update_deadline(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	if ((s64)(se->vruntime - se->deadline) < 0)
+		return;
+
+	/*
+	 * For EEVDF the virtual time slope is determined by w_i (iow.
+	 * nice) while the request time r_i is determined by
+	 * sysctl_sched_base_slice.
+	 */
+	se->slice = sysctl_sched_base_slice;
+
+	/*
+	 * EEVDF: vd_i = ve_i + r_i / w_i
+	 */
+	se->deadline = se->vruntime + calc_delta_fair(se->slice, se);
+
+	/*
+	 * The task has consumed its request, reschedule.
+	 */
+	if (cfs_rq->nr_running > 1) {
+		resched_curr(rq_of(cfs_rq));
+		clear_buddies(cfs_rq, se);
+	}
+}
+
+#include "pelt.h"
+#ifdef CONFIG_SMP
+
+static int select_idle_sibling(struct task_struct *p, int prev_cpu, int cpu);
+static unsigned long task_h_load(struct task_struct *p);
+static unsigned long capacity_of(int cpu);
+
+/* Give new sched_entity start runnable values to heavy its load in infant time */
+void init_entity_runnable_average(struct sched_entity *se)
+{
+	struct sched_avg *sa = &se->avg;
+
+	memset(sa, 0, sizeof(*sa));
+
+	/*
+	 * Tasks are initialized with full load to be seen as heavy tasks until
+	 * they get a chance to stabilize to their real load level.
+	 * Group entities are initialized with zero load to reflect the fact that
+	 * nothing has been attached to the task group yet.
+	 */
+	if (entity_is_task(se))
+		sa->load_avg = scale_load_down(se->load.weight);
+
+	/* when this task enqueue'ed, it will contribute to its cfs_rq's load_avg */
+}
+
+/*
+ * With new tasks being created, their initial util_avgs are extrapolated
+ * based on the cfs_rq's current util_avg:
+ *
+ *   util_avg = cfs_rq->util_avg / (cfs_rq->load_avg + 1) * se.load.weight
+ *
+ * However, in many cases, the above util_avg does not give a desired
+ * value. Moreover, the sum of the util_avgs may be divergent, such
+ * as when the series is a harmonic series.
+ *
+ * To solve this problem, we also cap the util_avg of successive tasks to
+ * only 1/2 of the left utilization budget:
+ *
+ *   util_avg_cap = (cpu_scale - cfs_rq->avg.util_avg) / 2^n
+ *
+ * where n denotes the nth task and cpu_scale the CPU capacity.
+ *
+ * For example, for a CPU with 1024 of capacity, a simplest series from
+ * the beginning would be like:
+ *
+ *  task  util_avg: 512, 256, 128,  64,  32,   16,    8, ...
+ * cfs_rq util_avg: 512, 768, 896, 960, 992, 1008, 1016, ...
+ *
+ * Finally, that extrapolated util_avg is clamped to the cap (util_avg_cap)
+ * if util_avg > util_avg_cap.
+ */
+void post_init_entity_util_avg(struct task_struct *p)
+{
+	struct sched_entity *se = &p->se;
+	struct cfs_rq *cfs_rq = cfs_rq_of(se);
+	struct sched_avg *sa = &se->avg;
+	long cpu_scale = arch_scale_cpu_capacity(cpu_of(rq_of(cfs_rq)));
+	long cap = (long)(cpu_scale - cfs_rq->avg.util_avg) / 2;
+
+	if (p->sched_class != &fair_sched_class) {
+		/*
+		 * For !fair tasks do:
+		 *
+		update_cfs_rq_load_avg(now, cfs_rq);
+		attach_entity_load_avg(cfs_rq, se);
+		switched_from_fair(rq, p);
+		 *
+		 * such that the next switched_to_fair() has the
+		 * expected state.
+		 */
+		se->avg.last_update_time = cfs_rq_clock_pelt(cfs_rq);
+		return;
+	}
+
+	if (cap > 0) {
+		if (cfs_rq->avg.util_avg != 0) {
+			sa->util_avg  = cfs_rq->avg.util_avg * se->load.weight;
+			sa->util_avg /= (cfs_rq->avg.load_avg + 1);
+
+			if (sa->util_avg > cap)
+				sa->util_avg = cap;
+		} else {
+			sa->util_avg = cap;
+		}
+	}
+
+	sa->runnable_avg = sa->util_avg;
+}
+
+#else /* !CONFIG_SMP */
+void init_entity_runnable_average(struct sched_entity *se)
+{
+}
+void post_init_entity_util_avg(struct task_struct *p)
+{
+}
+static void update_tg_load_avg(struct cfs_rq *cfs_rq)
+{
+}
+#endif /* CONFIG_SMP */
+
+/*
+ * Update the current task's runtime statistics.
+ */
+static void update_curr(struct cfs_rq *cfs_rq)
+{
+	struct sched_entity *curr = cfs_rq->curr;
+	u64 now = rq_clock_task(rq_of(cfs_rq));
+	u64 delta_exec;
+
+	if (unlikely(!curr))
+		return;
+
+	delta_exec = now - curr->exec_start;
+	if (unlikely((s64)delta_exec <= 0))
+		return;
+
+	curr->exec_start = now;
+
+	if (schedstat_enabled()) {
+		struct sched_statistics *stats;
+
+		stats = __schedstats_from_se(curr);
+		__schedstat_set(stats->exec_max,
+				max(delta_exec, stats->exec_max));
+	}
+
+	curr->sum_exec_runtime += delta_exec;
+	schedstat_add(cfs_rq->exec_clock, delta_exec);
+
+	curr->vruntime += calc_delta_fair(delta_exec, curr);
+	update_deadline(cfs_rq, curr);
+	update_min_vruntime(cfs_rq);
+
+	if (entity_is_task(curr)) {
+		struct task_struct *curtask = task_of(curr);
+
+		trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime);
+		cgroup_account_cputime(curtask, delta_exec);
+		account_group_exec_runtime(curtask, delta_exec);
+	}
+
+	account_cfs_rq_runtime(cfs_rq, delta_exec);
+}
+
+static void update_curr_fair(struct rq *rq)
+{
+	update_curr(cfs_rq_of(&rq->curr->se));
+}
+
+static inline void
+update_stats_wait_start_fair(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	struct sched_statistics *stats;
+	struct task_struct *p = NULL;
+
+	if (!schedstat_enabled())
+		return;
+
+	stats = __schedstats_from_se(se);
+
+	if (entity_is_task(se))
+		p = task_of(se);
+
+	__update_stats_wait_start(rq_of(cfs_rq), p, stats);
+}
+
+static inline void
+update_stats_wait_end_fair(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	struct sched_statistics *stats;
+	struct task_struct *p = NULL;
+
+	if (!schedstat_enabled())
+		return;
+
+	stats = __schedstats_from_se(se);
+
+	/*
+	 * When the sched_schedstat changes from 0 to 1, some sched se
+	 * maybe already in the runqueue, the se->statistics.wait_start
+	 * will be 0.So it will let the delta wrong. We need to avoid this
+	 * scenario.
+	 */
+	if (unlikely(!schedstat_val(stats->wait_start)))
+		return;
+
+	if (entity_is_task(se))
+		p = task_of(se);
+
+	__update_stats_wait_end(rq_of(cfs_rq), p, stats);
+}
+
+static inline void
+update_stats_enqueue_sleeper_fair(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	struct sched_statistics *stats;
+	struct task_struct *tsk = NULL;
+
+	if (!schedstat_enabled())
+		return;
+
+	stats = __schedstats_from_se(se);
+
+	if (entity_is_task(se))
+		tsk = task_of(se);
+
+	__update_stats_enqueue_sleeper(rq_of(cfs_rq), tsk, stats);
+}
+
+/*
+ * Task is being enqueued - update stats:
+ */
+static inline void
+update_stats_enqueue_fair(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
+{
+	if (!schedstat_enabled())
+		return;
+
+	/*
+	 * Are we enqueueing a waiting task? (for current tasks
+	 * a dequeue/enqueue event is a NOP)
+	 */
+	if (se != cfs_rq->curr)
+		update_stats_wait_start_fair(cfs_rq, se);
+
+	if (flags & ENQUEUE_WAKEUP)
+		update_stats_enqueue_sleeper_fair(cfs_rq, se);
+}
+
+static inline void
+update_stats_dequeue_fair(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
+{
+
+	if (!schedstat_enabled())
+		return;
+
+	/*
+	 * Mark the end of the wait period if dequeueing a
+	 * waiting task:
+	 */
+	if (se != cfs_rq->curr)
+		update_stats_wait_end_fair(cfs_rq, se);
+
+	if ((flags & DEQUEUE_SLEEP) && entity_is_task(se)) {
+		struct task_struct *tsk = task_of(se);
+		unsigned int state;
+
+		/* XXX racy against TTWU */
+		state = READ_ONCE(tsk->__state);
+		if (state & TASK_INTERRUPTIBLE)
+			__schedstat_set(tsk->stats.sleep_start,
+				      rq_clock(rq_of(cfs_rq)));
+		if (state & TASK_UNINTERRUPTIBLE)
+			__schedstat_set(tsk->stats.block_start,
+				      rq_clock(rq_of(cfs_rq)));
+	}
+}
+
+/*
+ * We are picking a new current task - update its stats:
+ */
+static inline void
+update_stats_curr_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	/*
+	 * We are starting a new run period:
+	 */
+	se->exec_start = rq_clock_task(rq_of(cfs_rq));
+}
+
+/**************************************************
+ * Scheduling class queueing methods:
+ */
+
+static inline bool is_core_idle(int cpu)
+{
+#ifdef CONFIG_SCHED_SMT
+	int sibling;
+
+	for_each_cpu(sibling, cpu_smt_mask(cpu)) {
+		if (cpu == sibling)
+			continue;
+
+		if (!idle_cpu(sibling))
+			return false;
+	}
+#endif
+
+	return true;
+}
+
+#ifdef CONFIG_NUMA
+#define NUMA_IMBALANCE_MIN 2
+
+static inline long
+adjust_numa_imbalance(int imbalance, int dst_running, int imb_numa_nr)
+{
+	/*
+	 * Allow a NUMA imbalance if busy CPUs is less than the maximum
+	 * threshold. Above this threshold, individual tasks may be contending
+	 * for both memory bandwidth and any shared HT resources.  This is an
+	 * approximation as the number of running tasks may not be related to
+	 * the number of busy CPUs due to sched_setaffinity.
+	 */
+	if (dst_running > imb_numa_nr)
+		return imbalance;
+
+	/*
+	 * Allow a small imbalance based on a simple pair of communicating
+	 * tasks that remain local when the destination is lightly loaded.
+	 */
+	if (imbalance <= NUMA_IMBALANCE_MIN)
+		return 0;
+
+	return imbalance;
+}
+#endif /* CONFIG_NUMA */
+
+#ifdef CONFIG_NUMA_BALANCING
+/*
+ * Approximate time to scan a full NUMA task in ms. The task scan period is
+ * calculated based on the tasks virtual memory size and
+ * numa_balancing_scan_size.
+ */
+unsigned int sysctl_numa_balancing_scan_period_min = 1000;
+unsigned int sysctl_numa_balancing_scan_period_max = 60000;
+
+/* Portion of address space to scan in MB */
+unsigned int sysctl_numa_balancing_scan_size = 256;
+
+/* Scan @scan_size MB every @scan_period after an initial @scan_delay in ms */
+unsigned int sysctl_numa_balancing_scan_delay = 1000;
+
+/* The page with hint page fault latency < threshold in ms is considered hot */
+unsigned int sysctl_numa_balancing_hot_threshold = MSEC_PER_SEC;
+
+struct numa_group {
+	refcount_t refcount;
+
+	spinlock_t lock; /* nr_tasks, tasks */
+	int nr_tasks;
+	pid_t gid;
+	int active_nodes;
+
+	struct rcu_head rcu;
+	unsigned long total_faults;
+	unsigned long max_faults_cpu;
+	/*
+	 * faults[] array is split into two regions: faults_mem and faults_cpu.
+	 *
+	 * Faults_cpu is used to decide whether memory should move
+	 * towards the CPU. As a consequence, these stats are weighted
+	 * more by CPU use than by memory faults.
+	 */
+	unsigned long faults[];
+};
+
+/*
+ * For functions that can be called in multiple contexts that permit reading
+ * ->numa_group (see struct task_struct for locking rules).
+ */
+static struct numa_group *deref_task_numa_group(struct task_struct *p)
+{
+	return rcu_dereference_check(p->numa_group, p == current ||
+		(lockdep_is_held(__rq_lockp(task_rq(p))) && !READ_ONCE(p->on_cpu)));
+}
+
+static struct numa_group *deref_curr_numa_group(struct task_struct *p)
+{
+	return rcu_dereference_protected(p->numa_group, p == current);
+}
+
+static inline unsigned long group_faults_priv(struct numa_group *ng);
+static inline unsigned long group_faults_shared(struct numa_group *ng);
+
+static unsigned int task_nr_scan_windows(struct task_struct *p)
+{
+	unsigned long rss = 0;
+	unsigned long nr_scan_pages;
+
+	/*
+	 * Calculations based on RSS as non-present and empty pages are skipped
+	 * by the PTE scanner and NUMA hinting faults should be trapped based
+	 * on resident pages
+	 */
+	nr_scan_pages = sysctl_numa_balancing_scan_size << (20 - PAGE_SHIFT);
+	rss = get_mm_rss(p->mm);
+	if (!rss)
+		rss = nr_scan_pages;
+
+	rss = round_up(rss, nr_scan_pages);
+	return rss / nr_scan_pages;
+}
+
+/* For sanity's sake, never scan more PTEs than MAX_SCAN_WINDOW MB/sec. */
+#define MAX_SCAN_WINDOW 2560
+
+static unsigned int task_scan_min(struct task_struct *p)
+{
+	unsigned int scan_size = READ_ONCE(sysctl_numa_balancing_scan_size);
+	unsigned int scan, floor;
+	unsigned int windows = 1;
+
+	if (scan_size < MAX_SCAN_WINDOW)
+		windows = MAX_SCAN_WINDOW / scan_size;
+	floor = 1000 / windows;
+
+	scan = sysctl_numa_balancing_scan_period_min / task_nr_scan_windows(p);
+	return max_t(unsigned int, floor, scan);
+}
+
+static unsigned int task_scan_start(struct task_struct *p)
+{
+	unsigned long smin = task_scan_min(p);
+	unsigned long period = smin;
+	struct numa_group *ng;
+
+	/* Scale the maximum scan period with the amount of shared memory. */
+	rcu_read_lock();
+	ng = rcu_dereference(p->numa_group);
+	if (ng) {
+		unsigned long shared = group_faults_shared(ng);
+		unsigned long private = group_faults_priv(ng);
+
+		period *= refcount_read(&ng->refcount);
+		period *= shared + 1;
+		period /= private + shared + 1;
+	}
+	rcu_read_unlock();
+
+	return max(smin, period);
+}
+
+static unsigned int task_scan_max(struct task_struct *p)
+{
+	unsigned long smin = task_scan_min(p);
+	unsigned long smax;
+	struct numa_group *ng;
+
+	/* Watch for min being lower than max due to floor calculations */
+	smax = sysctl_numa_balancing_scan_period_max / task_nr_scan_windows(p);
+
+	/* Scale the maximum scan period with the amount of shared memory. */
+	ng = deref_curr_numa_group(p);
+	if (ng) {
+		unsigned long shared = group_faults_shared(ng);
+		unsigned long private = group_faults_priv(ng);
+		unsigned long period = smax;
+
+		period *= refcount_read(&ng->refcount);
+		period *= shared + 1;
+		period /= private + shared + 1;
+
+		smax = max(smax, period);
+	}
+
+	return max(smin, smax);
+}
+
+static void account_numa_enqueue(struct rq *rq, struct task_struct *p)
+{
+	rq->nr_numa_running += (p->numa_preferred_nid != NUMA_NO_NODE);
+	rq->nr_preferred_running += (p->numa_preferred_nid == task_node(p));
+}
+
+static void account_numa_dequeue(struct rq *rq, struct task_struct *p)
+{
+	rq->nr_numa_running -= (p->numa_preferred_nid != NUMA_NO_NODE);
+	rq->nr_preferred_running -= (p->numa_preferred_nid == task_node(p));
+}
+
+/* Shared or private faults. */
+#define NR_NUMA_HINT_FAULT_TYPES 2
+
+/* Memory and CPU locality */
+#define NR_NUMA_HINT_FAULT_STATS (NR_NUMA_HINT_FAULT_TYPES * 2)
+
+/* Averaged statistics, and temporary buffers. */
+#define NR_NUMA_HINT_FAULT_BUCKETS (NR_NUMA_HINT_FAULT_STATS * 2)
+
+pid_t task_numa_group_id(struct task_struct *p)
+{
+	struct numa_group *ng;
+	pid_t gid = 0;
+
+	rcu_read_lock();
+	ng = rcu_dereference(p->numa_group);
+	if (ng)
+		gid = ng->gid;
+	rcu_read_unlock();
+
+	return gid;
+}
+
+/*
+ * The averaged statistics, shared & private, memory & CPU,
+ * occupy the first half of the array. The second half of the
+ * array is for current counters, which are averaged into the
+ * first set by task_numa_placement.
+ */
+static inline int task_faults_idx(enum numa_faults_stats s, int nid, int priv)
+{
+	return NR_NUMA_HINT_FAULT_TYPES * (s * nr_node_ids + nid) + priv;
+}
+
+static inline unsigned long task_faults(struct task_struct *p, int nid)
+{
+	if (!p->numa_faults)
+		return 0;
+
+	return p->numa_faults[task_faults_idx(NUMA_MEM, nid, 0)] +
+		p->numa_faults[task_faults_idx(NUMA_MEM, nid, 1)];
+}
+
+static inline unsigned long group_faults(struct task_struct *p, int nid)
+{
+	struct numa_group *ng = deref_task_numa_group(p);
+
+	if (!ng)
+		return 0;
+
+	return ng->faults[task_faults_idx(NUMA_MEM, nid, 0)] +
+		ng->faults[task_faults_idx(NUMA_MEM, nid, 1)];
+}
+
+static inline unsigned long group_faults_cpu(struct numa_group *group, int nid)
+{
+	return group->faults[task_faults_idx(NUMA_CPU, nid, 0)] +
+		group->faults[task_faults_idx(NUMA_CPU, nid, 1)];
+}
+
+static inline unsigned long group_faults_priv(struct numa_group *ng)
+{
+	unsigned long faults = 0;
+	int node;
+
+	for_each_online_node(node) {
+		faults += ng->faults[task_faults_idx(NUMA_MEM, node, 1)];
+	}
+
+	return faults;
+}
+
+static inline unsigned long group_faults_shared(struct numa_group *ng)
+{
+	unsigned long faults = 0;
+	int node;
+
+	for_each_online_node(node) {
+		faults += ng->faults[task_faults_idx(NUMA_MEM, node, 0)];
+	}
+
+	return faults;
+}
+
+/*
+ * A node triggering more than 1/3 as many NUMA faults as the maximum is
+ * considered part of a numa group's pseudo-interleaving set. Migrations
+ * between these nodes are slowed down, to allow things to settle down.
+ */
+#define ACTIVE_NODE_FRACTION 3
+
+static bool numa_is_active_node(int nid, struct numa_group *ng)
+{
+	return group_faults_cpu(ng, nid) * ACTIVE_NODE_FRACTION > ng->max_faults_cpu;
+}
+
+/* Handle placement on systems where not all nodes are directly connected. */
+static unsigned long score_nearby_nodes(struct task_struct *p, int nid,
+					int lim_dist, bool task)
+{
+	unsigned long score = 0;
+	int node, max_dist;
+
+	/*
+	 * All nodes are directly connected, and the same distance
+	 * from each other. No need for fancy placement algorithms.
+	 */
+	if (sched_numa_topology_type == NUMA_DIRECT)
+		return 0;
+
+	/* sched_max_numa_distance may be changed in parallel. */
+	max_dist = READ_ONCE(sched_max_numa_distance);
+	/*
+	 * This code is called for each node, introducing N^2 complexity,
+	 * which should be ok given the number of nodes rarely exceeds 8.
+	 */
+	for_each_online_node(node) {
+		unsigned long faults;
+		int dist = node_distance(nid, node);
+
+		/*
+		 * The furthest away nodes in the system are not interesting
+		 * for placement; nid was already counted.
+		 */
+		if (dist >= max_dist || node == nid)
+			continue;
+
+		/*
+		 * On systems with a backplane NUMA topology, compare groups
+		 * of nodes, and move tasks towards the group with the most
+		 * memory accesses. When comparing two nodes at distance
+		 * "hoplimit", only nodes closer by than "hoplimit" are part
+		 * of each group. Skip other nodes.
+		 */
+		if (sched_numa_topology_type == NUMA_BACKPLANE && dist >= lim_dist)
+			continue;
+
+		/* Add up the faults from nearby nodes. */
+		if (task)
+			faults = task_faults(p, node);
+		else
+			faults = group_faults(p, node);
+
+		/*
+		 * On systems with a glueless mesh NUMA topology, there are
+		 * no fixed "groups of nodes". Instead, nodes that are not
+		 * directly connected bounce traffic through intermediate
+		 * nodes; a numa_group can occupy any set of nodes.
+		 * The further away a node is, the less the faults count.
+		 * This seems to result in good task placement.
+		 */
+		if (sched_numa_topology_type == NUMA_GLUELESS_MESH) {
+			faults *= (max_dist - dist);
+			faults /= (max_dist - LOCAL_DISTANCE);
+		}
+
+		score += faults;
+	}
+
+	return score;
+}
+
+/*
+ * These return the fraction of accesses done by a particular task, or
+ * task group, on a particular numa node.  The group weight is given a
+ * larger multiplier, in order to group tasks together that are almost
+ * evenly spread out between numa nodes.
+ */
+static inline unsigned long task_weight(struct task_struct *p, int nid,
+					int dist)
+{
+	unsigned long faults, total_faults;
+
+	if (!p->numa_faults)
+		return 0;
+
+	total_faults = p->total_numa_faults;
+
+	if (!total_faults)
+		return 0;
+
+	faults = task_faults(p, nid);
+	faults += score_nearby_nodes(p, nid, dist, true);
+
+	return 1000 * faults / total_faults;
+}
+
+static inline unsigned long group_weight(struct task_struct *p, int nid,
+					 int dist)
+{
+	struct numa_group *ng = deref_task_numa_group(p);
+	unsigned long faults, total_faults;
+
+	if (!ng)
+		return 0;
+
+	total_faults = ng->total_faults;
+
+	if (!total_faults)
+		return 0;
+
+	faults = group_faults(p, nid);
+	faults += score_nearby_nodes(p, nid, dist, false);
+
+	return 1000 * faults / total_faults;
+}
+
+/*
+ * If memory tiering mode is enabled, cpupid of slow memory page is
+ * used to record scan time instead of CPU and PID.  When tiering mode
+ * is disabled at run time, the scan time (in cpupid) will be
+ * interpreted as CPU and PID.  So CPU needs to be checked to avoid to
+ * access out of array bound.
+ */
+static inline bool cpupid_valid(int cpupid)
+{
+	return cpupid_to_cpu(cpupid) < nr_cpu_ids;
+}
+
+/*
+ * For memory tiering mode, if there are enough free pages (more than
+ * enough watermark defined here) in fast memory node, to take full
+ * advantage of fast memory capacity, all recently accessed slow
+ * memory pages will be migrated to fast memory node without
+ * considering hot threshold.
+ */
+static bool pgdat_free_space_enough(struct pglist_data *pgdat)
+{
+	int z;
+	unsigned long enough_wmark;
+
+	enough_wmark = max(1UL * 1024 * 1024 * 1024 >> PAGE_SHIFT,
+			   pgdat->node_present_pages >> 4);
+	for (z = pgdat->nr_zones - 1; z >= 0; z--) {
+		struct zone *zone = pgdat->node_zones + z;
+
+		if (!populated_zone(zone))
+			continue;
+
+		if (zone_watermark_ok(zone, 0,
+				      wmark_pages(zone, WMARK_PROMO) + enough_wmark,
+				      ZONE_MOVABLE, 0))
+			return true;
+	}
+	return false;
+}
+
+/*
+ * For memory tiering mode, when page tables are scanned, the scan
+ * time will be recorded in struct page in addition to make page
+ * PROT_NONE for slow memory page.  So when the page is accessed, in
+ * hint page fault handler, the hint page fault latency is calculated
+ * via,
+ *
+ *	hint page fault latency = hint page fault time - scan time
+ *
+ * The smaller the hint page fault latency, the higher the possibility
+ * for the page to be hot.
+ */
+static int numa_hint_fault_latency(struct page *page)
+{
+	int last_time, time;
+
+	time = jiffies_to_msecs(jiffies);
+	last_time = xchg_page_access_time(page, time);
+
+	return (time - last_time) & PAGE_ACCESS_TIME_MASK;
+}
+
+/*
+ * For memory tiering mode, too high promotion/demotion throughput may
+ * hurt application latency.  So we provide a mechanism to rate limit
+ * the number of pages that are tried to be promoted.
+ */
+static bool numa_promotion_rate_limit(struct pglist_data *pgdat,
+				      unsigned long rate_limit, int nr)
+{
+	unsigned long nr_cand;
+	unsigned int now, start;
+
+	now = jiffies_to_msecs(jiffies);
+	mod_node_page_state(pgdat, PGPROMOTE_CANDIDATE, nr);
+	nr_cand = node_page_state(pgdat, PGPROMOTE_CANDIDATE);
+	start = pgdat->nbp_rl_start;
+	if (now - start > MSEC_PER_SEC &&
+	    cmpxchg(&pgdat->nbp_rl_start, start, now) == start)
+		pgdat->nbp_rl_nr_cand = nr_cand;
+	if (nr_cand - pgdat->nbp_rl_nr_cand >= rate_limit)
+		return true;
+	return false;
+}
+
+#define NUMA_MIGRATION_ADJUST_STEPS	16
+
+static void numa_promotion_adjust_threshold(struct pglist_data *pgdat,
+					    unsigned long rate_limit,
+					    unsigned int ref_th)
+{
+	unsigned int now, start, th_period, unit_th, th;
+	unsigned long nr_cand, ref_cand, diff_cand;
+
+	now = jiffies_to_msecs(jiffies);
+	th_period = sysctl_numa_balancing_scan_period_max;
+	start = pgdat->nbp_th_start;
+	if (now - start > th_period &&
+	    cmpxchg(&pgdat->nbp_th_start, start, now) == start) {
+		ref_cand = rate_limit *
+			sysctl_numa_balancing_scan_period_max / MSEC_PER_SEC;
+		nr_cand = node_page_state(pgdat, PGPROMOTE_CANDIDATE);
+		diff_cand = nr_cand - pgdat->nbp_th_nr_cand;
+		unit_th = ref_th * 2 / NUMA_MIGRATION_ADJUST_STEPS;
+		th = pgdat->nbp_threshold ? : ref_th;
+		if (diff_cand > ref_cand * 11 / 10)
+			th = max(th - unit_th, unit_th);
+		else if (diff_cand < ref_cand * 9 / 10)
+			th = min(th + unit_th, ref_th * 2);
+		pgdat->nbp_th_nr_cand = nr_cand;
+		pgdat->nbp_threshold = th;
+	}
+}
+
+bool should_numa_migrate_memory(struct task_struct *p, struct page * page,
+				int src_nid, int dst_cpu)
+{
+	struct numa_group *ng = deref_curr_numa_group(p);
+	int dst_nid = cpu_to_node(dst_cpu);
+	int last_cpupid, this_cpupid;
+
+	/*
+	 * The pages in slow memory node should be migrated according
+	 * to hot/cold instead of private/shared.
+	 */
+	if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING &&
+	    !node_is_toptier(src_nid)) {
+		struct pglist_data *pgdat;
+		unsigned long rate_limit;
+		unsigned int latency, th, def_th;
+
+		pgdat = NODE_DATA(dst_nid);
+		if (pgdat_free_space_enough(pgdat)) {
+			/* workload changed, reset hot threshold */
+			pgdat->nbp_threshold = 0;
+			return true;
+		}
+
+		def_th = sysctl_numa_balancing_hot_threshold;
+		rate_limit = sysctl_numa_balancing_promote_rate_limit << \
+			(20 - PAGE_SHIFT);
+		numa_promotion_adjust_threshold(pgdat, rate_limit, def_th);
+
+		th = pgdat->nbp_threshold ? : def_th;
+		latency = numa_hint_fault_latency(page);
+		if (latency >= th)
+			return false;
+
+		return !numa_promotion_rate_limit(pgdat, rate_limit,
+						  thp_nr_pages(page));
+	}
+
+	this_cpupid = cpu_pid_to_cpupid(dst_cpu, current->pid);
+	last_cpupid = page_cpupid_xchg_last(page, this_cpupid);
+
+	if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) &&
+	    !node_is_toptier(src_nid) && !cpupid_valid(last_cpupid))
+		return false;
+
+	/*
+	 * Allow first faults or private faults to migrate immediately early in
+	 * the lifetime of a task. The magic number 4 is based on waiting for
+	 * two full passes of the "multi-stage node selection" test that is
+	 * executed below.
+	 */
+	if ((p->numa_preferred_nid == NUMA_NO_NODE || p->numa_scan_seq <= 4) &&
+	    (cpupid_pid_unset(last_cpupid) || cpupid_match_pid(p, last_cpupid)))
+		return true;
+
+	/*
+	 * Multi-stage node selection is used in conjunction with a periodic
+	 * migration fault to build a temporal task<->page relation. By using
+	 * a two-stage filter we remove short/unlikely relations.
+	 *
+	 * Using P(p) ~ n_p / n_t as per frequentist probability, we can equate
+	 * a task's usage of a particular page (n_p) per total usage of this
+	 * page (n_t) (in a given time-span) to a probability.
+	 *
+	 * Our periodic faults will sample this probability and getting the
+	 * same result twice in a row, given these samples are fully
+	 * independent, is then given by P(n)^2, provided our sample period
+	 * is sufficiently short compared to the usage pattern.
+	 *
+	 * This quadric squishes small probabilities, making it less likely we
+	 * act on an unlikely task<->page relation.
+	 */
+	if (!cpupid_pid_unset(last_cpupid) &&
+				cpupid_to_nid(last_cpupid) != dst_nid)
+		return false;
+
+	/* Always allow migrate on private faults */
+	if (cpupid_match_pid(p, last_cpupid))
+		return true;
+
+	/* A shared fault, but p->numa_group has not been set up yet. */
+	if (!ng)
+		return true;
+
+	/*
+	 * Destination node is much more heavily used than the source
+	 * node? Allow migration.
+	 */
+	if (group_faults_cpu(ng, dst_nid) > group_faults_cpu(ng, src_nid) *
+					ACTIVE_NODE_FRACTION)
+		return true;
+
+	/*
+	 * Distribute memory according to CPU & memory use on each node,
+	 * with 3/4 hysteresis to avoid unnecessary memory migrations:
+	 *
+	 * faults_cpu(dst)   3   faults_cpu(src)
+	 * --------------- * - > ---------------
+	 * faults_mem(dst)   4   faults_mem(src)
+	 */
+	return group_faults_cpu(ng, dst_nid) * group_faults(p, src_nid) * 3 >
+	       group_faults_cpu(ng, src_nid) * group_faults(p, dst_nid) * 4;
+}
+
+/*
+ * 'numa_type' describes the node at the moment of load balancing.
+ */
+enum numa_type {
+	/* The node has spare capacity that can be used to run more tasks.  */
+	node_has_spare = 0,
+	/*
+	 * The node is fully used and the tasks don't compete for more CPU
+	 * cycles. Nevertheless, some tasks might wait before running.
+	 */
+	node_fully_busy,
+	/*
+	 * The node is overloaded and can't provide expected CPU cycles to all
+	 * tasks.
+	 */
+	node_overloaded
+};
+
+/* Cached statistics for all CPUs within a node */
+struct numa_stats {
+	unsigned long load;
+	unsigned long runnable;
+	unsigned long util;
+	/* Total compute capacity of CPUs on a node */
+	unsigned long compute_capacity;
+	unsigned int nr_running;
+	unsigned int weight;
+	enum numa_type node_type;
+	int idle_cpu;
+};
+
+struct task_numa_env {
+	struct task_struct *p;
+
+	int src_cpu, src_nid;
+	int dst_cpu, dst_nid;
+	int imb_numa_nr;
+
+	struct numa_stats src_stats, dst_stats;
+
+	int imbalance_pct;
+	int dist;
+
+	struct task_struct *best_task;
+	long best_imp;
+	int best_cpu;
+};
+
+static unsigned long cpu_load(struct rq *rq);
+static unsigned long cpu_runnable(struct rq *rq);
+
+static inline enum
+numa_type numa_classify(unsigned int imbalance_pct,
+			 struct numa_stats *ns)
+{
+	if ((ns->nr_running > ns->weight) &&
+	    (((ns->compute_capacity * 100) < (ns->util * imbalance_pct)) ||
+	     ((ns->compute_capacity * imbalance_pct) < (ns->runnable * 100))))
+		return node_overloaded;
+
+	if ((ns->nr_running < ns->weight) ||
+	    (((ns->compute_capacity * 100) > (ns->util * imbalance_pct)) &&
+	     ((ns->compute_capacity * imbalance_pct) > (ns->runnable * 100))))
+		return node_has_spare;
+
+	return node_fully_busy;
+}
+
+#ifdef CONFIG_SCHED_SMT
+/* Forward declarations of select_idle_sibling helpers */
+static inline bool test_idle_cores(int cpu);
+static inline int numa_idle_core(int idle_core, int cpu)
+{
+	if (!static_branch_likely(&sched_smt_present) ||
+	    idle_core >= 0 || !test_idle_cores(cpu))
+		return idle_core;
+
+	/*
+	 * Prefer cores instead of packing HT siblings
+	 * and triggering future load balancing.
+	 */
+	if (is_core_idle(cpu))
+		idle_core = cpu;
+
+	return idle_core;
+}
+#else
+static inline int numa_idle_core(int idle_core, int cpu)
+{
+	return idle_core;
+}
+#endif
+
+/*
+ * Gather all necessary information to make NUMA balancing placement
+ * decisions that are compatible with standard load balancer. This
+ * borrows code and logic from update_sg_lb_stats but sharing a
+ * common implementation is impractical.
+ */
+static void update_numa_stats(struct task_numa_env *env,
+			      struct numa_stats *ns, int nid,
+			      bool find_idle)
+{
+	int cpu, idle_core = -1;
+
+	memset(ns, 0, sizeof(*ns));
+	ns->idle_cpu = -1;
+
+	rcu_read_lock();
+	for_each_cpu(cpu, cpumask_of_node(nid)) {
+		struct rq *rq = cpu_rq(cpu);
+
+		ns->load += cpu_load(rq);
+		ns->runnable += cpu_runnable(rq);
+		ns->util += cpu_util_cfs(cpu);
+		ns->nr_running += rq->cfs.h_nr_running;
+		ns->compute_capacity += capacity_of(cpu);
+
+		if (find_idle && idle_core < 0 && !rq->nr_running && idle_cpu(cpu)) {
+			if (READ_ONCE(rq->numa_migrate_on) ||
+			    !cpumask_test_cpu(cpu, env->p->cpus_ptr))
+				continue;
+
+			if (ns->idle_cpu == -1)
+				ns->idle_cpu = cpu;
+
+			idle_core = numa_idle_core(idle_core, cpu);
+		}
+	}
+	rcu_read_unlock();
+
+	ns->weight = cpumask_weight(cpumask_of_node(nid));
+
+	ns->node_type = numa_classify(env->imbalance_pct, ns);
+
+	if (idle_core >= 0)
+		ns->idle_cpu = idle_core;
+}
+
+static void task_numa_assign(struct task_numa_env *env,
+			     struct task_struct *p, long imp)
+{
+	struct rq *rq = cpu_rq(env->dst_cpu);
+
+	/* Check if run-queue part of active NUMA balance. */
+	if (env->best_cpu != env->dst_cpu && xchg(&rq->numa_migrate_on, 1)) {
+		int cpu;
+		int start = env->dst_cpu;
+
+		/* Find alternative idle CPU. */
+		for_each_cpu_wrap(cpu, cpumask_of_node(env->dst_nid), start + 1) {
+			if (cpu == env->best_cpu || !idle_cpu(cpu) ||
+			    !cpumask_test_cpu(cpu, env->p->cpus_ptr)) {
+				continue;
+			}
+
+			env->dst_cpu = cpu;
+			rq = cpu_rq(env->dst_cpu);
+			if (!xchg(&rq->numa_migrate_on, 1))
+				goto assign;
+		}
+
+		/* Failed to find an alternative idle CPU */
+		return;
+	}
+
+assign:
+	/*
+	 * Clear previous best_cpu/rq numa-migrate flag, since task now
+	 * found a better CPU to move/swap.
+	 */
+	if (env->best_cpu != -1 && env->best_cpu != env->dst_cpu) {
+		rq = cpu_rq(env->best_cpu);
+		WRITE_ONCE(rq->numa_migrate_on, 0);
+	}
+
+	if (env->best_task)
+		put_task_struct(env->best_task);
+	if (p)
+		get_task_struct(p);
+
+	env->best_task = p;
+	env->best_imp = imp;
+	env->best_cpu = env->dst_cpu;
+}
+
+static bool load_too_imbalanced(long src_load, long dst_load,
+				struct task_numa_env *env)
+{
+	long imb, old_imb;
+	long orig_src_load, orig_dst_load;
+	long src_capacity, dst_capacity;
+
+	/*
+	 * The load is corrected for the CPU capacity available on each node.
+	 *
+	 * src_load        dst_load
+	 * ------------ vs ---------
+	 * src_capacity    dst_capacity
+	 */
+	src_capacity = env->src_stats.compute_capacity;
+	dst_capacity = env->dst_stats.compute_capacity;
+
+	imb = abs(dst_load * src_capacity - src_load * dst_capacity);
+
+	orig_src_load = env->src_stats.load;
+	orig_dst_load = env->dst_stats.load;
+
+	old_imb = abs(orig_dst_load * src_capacity - orig_src_load * dst_capacity);
+
+	/* Would this change make things worse? */
+	return (imb > old_imb);
+}
+
+/*
+ * Maximum NUMA importance can be 1998 (2*999);
+ * SMALLIMP @ 30 would be close to 1998/64.
+ * Used to deter task migration.
+ */
+#define SMALLIMP	30
+
+/*
+ * This checks if the overall compute and NUMA accesses of the system would
+ * be improved if the source tasks was migrated to the target dst_cpu taking
+ * into account that it might be best if task running on the dst_cpu should
+ * be exchanged with the source task
+ */
+static bool task_numa_compare(struct task_numa_env *env,
+			      long taskimp, long groupimp, bool maymove)
+{
+	struct numa_group *cur_ng, *p_ng = deref_curr_numa_group(env->p);
+	struct rq *dst_rq = cpu_rq(env->dst_cpu);
+	long imp = p_ng ? groupimp : taskimp;
+	struct task_struct *cur;
+	long src_load, dst_load;
+	int dist = env->dist;
+	long moveimp = imp;
+	long load;
+	bool stopsearch = false;
+
+	if (READ_ONCE(dst_rq->numa_migrate_on))
+		return false;
+
+	rcu_read_lock();
+	cur = rcu_dereference(dst_rq->curr);
+	if (cur && ((cur->flags & PF_EXITING) || is_idle_task(cur)))
+		cur = NULL;
+
+	/*
+	 * Because we have preemption enabled we can get migrated around and
+	 * end try selecting ourselves (current == env->p) as a swap candidate.
+	 */
+	if (cur == env->p) {
+		stopsearch = true;
+		goto unlock;
+	}
+
+	if (!cur) {
+		if (maymove && moveimp >= env->best_imp)
+			goto assign;
+		else
+			goto unlock;
+	}
+
+	/* Skip this swap candidate if cannot move to the source cpu. */
+	if (!cpumask_test_cpu(env->src_cpu, cur->cpus_ptr))
+		goto unlock;
+
+	/*
+	 * Skip this swap candidate if it is not moving to its preferred
+	 * node and the best task is.
+	 */
+	if (env->best_task &&
+	    env->best_task->numa_preferred_nid == env->src_nid &&
+	    cur->numa_preferred_nid != env->src_nid) {
+		goto unlock;
+	}
+
+	/*
+	 * "imp" is the fault differential for the source task between the
+	 * source and destination node. Calculate the total differential for
+	 * the source task and potential destination task. The more negative
+	 * the value is, the more remote accesses that would be expected to
+	 * be incurred if the tasks were swapped.
+	 *
+	 * If dst and source tasks are in the same NUMA group, or not
+	 * in any group then look only at task weights.
+	 */
+	cur_ng = rcu_dereference(cur->numa_group);
+	if (cur_ng == p_ng) {
+		/*
+		 * Do not swap within a group or between tasks that have
+		 * no group if there is spare capacity. Swapping does
+		 * not address the load imbalance and helps one task at
+		 * the cost of punishing another.
+		 */
+		if (env->dst_stats.node_type == node_has_spare)
+			goto unlock;
+
+		imp = taskimp + task_weight(cur, env->src_nid, dist) -
+		      task_weight(cur, env->dst_nid, dist);
+		/*
+		 * Add some hysteresis to prevent swapping the
+		 * tasks within a group over tiny differences.
+		 */
+		if (cur_ng)
+			imp -= imp / 16;
+	} else {
+		/*
+		 * Compare the group weights. If a task is all by itself
+		 * (not part of a group), use the task weight instead.
+		 */
+		if (cur_ng && p_ng)
+			imp += group_weight(cur, env->src_nid, dist) -
+			       group_weight(cur, env->dst_nid, dist);
+		else
+			imp += task_weight(cur, env->src_nid, dist) -
+			       task_weight(cur, env->dst_nid, dist);
+	}
+
+	/* Discourage picking a task already on its preferred node */
+	if (cur->numa_preferred_nid == env->dst_nid)
+		imp -= imp / 16;
+
+	/*
+	 * Encourage picking a task that moves to its preferred node.
+	 * This potentially makes imp larger than it's maximum of
+	 * 1998 (see SMALLIMP and task_weight for why) but in this
+	 * case, it does not matter.
+	 */
+	if (cur->numa_preferred_nid == env->src_nid)
+		imp += imp / 8;
+
+	if (maymove && moveimp > imp && moveimp > env->best_imp) {
+		imp = moveimp;
+		cur = NULL;
+		goto assign;
+	}
+
+	/*
+	 * Prefer swapping with a task moving to its preferred node over a
+	 * task that is not.
+	 */
+	if (env->best_task && cur->numa_preferred_nid == env->src_nid &&
+	    env->best_task->numa_preferred_nid != env->src_nid) {
+		goto assign;
+	}
+
+	/*
+	 * If the NUMA importance is less than SMALLIMP,
+	 * task migration might only result in ping pong
+	 * of tasks and also hurt performance due to cache
+	 * misses.
+	 */
+	if (imp < SMALLIMP || imp <= env->best_imp + SMALLIMP / 2)
+		goto unlock;
+
+	/*
+	 * In the overloaded case, try and keep the load balanced.
+	 */
+	load = task_h_load(env->p) - task_h_load(cur);
+	if (!load)
+		goto assign;
+
+	dst_load = env->dst_stats.load + load;
+	src_load = env->src_stats.load - load;
+
+	if (load_too_imbalanced(src_load, dst_load, env))
+		goto unlock;
+
+assign:
+	/* Evaluate an idle CPU for a task numa move. */
+	if (!cur) {
+		int cpu = env->dst_stats.idle_cpu;
+
+		/* Nothing cached so current CPU went idle since the search. */
+		if (cpu < 0)
+			cpu = env->dst_cpu;
+
+		/*
+		 * If the CPU is no longer truly idle and the previous best CPU
+		 * is, keep using it.
+		 */
+		if (!idle_cpu(cpu) && env->best_cpu >= 0 &&
+		    idle_cpu(env->best_cpu)) {
+			cpu = env->best_cpu;
+		}
+
+		env->dst_cpu = cpu;
+	}
+
+	task_numa_assign(env, cur, imp);
+
+	/*
+	 * If a move to idle is allowed because there is capacity or load
+	 * balance improves then stop the search. While a better swap
+	 * candidate may exist, a search is not free.
+	 */
+	if (maymove && !cur && env->best_cpu >= 0 && idle_cpu(env->best_cpu))
+		stopsearch = true;
+
+	/*
+	 * If a swap candidate must be identified and the current best task
+	 * moves its preferred node then stop the search.
+	 */
+	if (!maymove && env->best_task &&
+	    env->best_task->numa_preferred_nid == env->src_nid) {
+		stopsearch = true;
+	}
+unlock:
+	rcu_read_unlock();
+
+	return stopsearch;
+}
+
+static void task_numa_find_cpu(struct task_numa_env *env,
+				long taskimp, long groupimp)
+{
+	bool maymove = false;
+	int cpu;
+
+	/*
+	 * If dst node has spare capacity, then check if there is an
+	 * imbalance that would be overruled by the load balancer.
+	 */
+	if (env->dst_stats.node_type == node_has_spare) {
+		unsigned int imbalance;
+		int src_running, dst_running;
+
+		/*
+		 * Would movement cause an imbalance? Note that if src has
+		 * more running tasks that the imbalance is ignored as the
+		 * move improves the imbalance from the perspective of the
+		 * CPU load balancer.
+		 * */
+		src_running = env->src_stats.nr_running - 1;
+		dst_running = env->dst_stats.nr_running + 1;
+		imbalance = max(0, dst_running - src_running);
+		imbalance = adjust_numa_imbalance(imbalance, dst_running,
+						  env->imb_numa_nr);
+
+		/* Use idle CPU if there is no imbalance */
+		if (!imbalance) {
+			maymove = true;
+			if (env->dst_stats.idle_cpu >= 0) {
+				env->dst_cpu = env->dst_stats.idle_cpu;
+				task_numa_assign(env, NULL, 0);
+				return;
+			}
+		}
+	} else {
+		long src_load, dst_load, load;
+		/*
+		 * If the improvement from just moving env->p direction is better
+		 * than swapping tasks around, check if a move is possible.
+		 */
+		load = task_h_load(env->p);
+		dst_load = env->dst_stats.load + load;
+		src_load = env->src_stats.load - load;
+		maymove = !load_too_imbalanced(src_load, dst_load, env);
+	}
+
+	for_each_cpu(cpu, cpumask_of_node(env->dst_nid)) {
+		/* Skip this CPU if the source task cannot migrate */
+		if (!cpumask_test_cpu(cpu, env->p->cpus_ptr))
+			continue;
+
+		env->dst_cpu = cpu;
+		if (task_numa_compare(env, taskimp, groupimp, maymove))
+			break;
+	}
+}
+
+static int task_numa_migrate(struct task_struct *p)
+{
+	struct task_numa_env env = {
+		.p = p,
+
+		.src_cpu = task_cpu(p),
+		.src_nid = task_node(p),
+
+		.imbalance_pct = 112,
+
+		.best_task = NULL,
+		.best_imp = 0,
+		.best_cpu = -1,
+	};
+	unsigned long taskweight, groupweight;
+	struct sched_domain *sd;
+	long taskimp, groupimp;
+	struct numa_group *ng;
+	struct rq *best_rq;
+	int nid, ret, dist;
+
+	/*
+	 * Pick the lowest SD_NUMA domain, as that would have the smallest
+	 * imbalance and would be the first to start moving tasks about.
+	 *
+	 * And we want to avoid any moving of tasks about, as that would create
+	 * random movement of tasks -- counter the numa conditions we're trying
+	 * to satisfy here.
+	 */
+	rcu_read_lock();
+	sd = rcu_dereference(per_cpu(sd_numa, env.src_cpu));
+	if (sd) {
+		env.imbalance_pct = 100 + (sd->imbalance_pct - 100) / 2;
+		env.imb_numa_nr = sd->imb_numa_nr;
+	}
+	rcu_read_unlock();
+
+	/*
+	 * Cpusets can break the scheduler domain tree into smaller
+	 * balance domains, some of which do not cross NUMA boundaries.
+	 * Tasks that are "trapped" in such domains cannot be migrated
+	 * elsewhere, so there is no point in (re)trying.
+	 */
+	if (unlikely(!sd)) {
+		sched_setnuma(p, task_node(p));
+		return -EINVAL;
+	}
+
+	env.dst_nid = p->numa_preferred_nid;
+	dist = env.dist = node_distance(env.src_nid, env.dst_nid);
+	taskweight = task_weight(p, env.src_nid, dist);
+	groupweight = group_weight(p, env.src_nid, dist);
+	update_numa_stats(&env, &env.src_stats, env.src_nid, false);
+	taskimp = task_weight(p, env.dst_nid, dist) - taskweight;
+	groupimp = group_weight(p, env.dst_nid, dist) - groupweight;
+	update_numa_stats(&env, &env.dst_stats, env.dst_nid, true);
+
+	/* Try to find a spot on the preferred nid. */
+	task_numa_find_cpu(&env, taskimp, groupimp);
+
+	/*
+	 * Look at other nodes in these cases:
+	 * - there is no space available on the preferred_nid
+	 * - the task is part of a numa_group that is interleaved across
+	 *   multiple NUMA nodes; in order to better consolidate the group,
+	 *   we need to check other locations.
+	 */
+	ng = deref_curr_numa_group(p);
+	if (env.best_cpu == -1 || (ng && ng->active_nodes > 1)) {
+		for_each_node_state(nid, N_CPU) {
+			if (nid == env.src_nid || nid == p->numa_preferred_nid)
+				continue;
+
+			dist = node_distance(env.src_nid, env.dst_nid);
+			if (sched_numa_topology_type == NUMA_BACKPLANE &&
+						dist != env.dist) {
+				taskweight = task_weight(p, env.src_nid, dist);
+				groupweight = group_weight(p, env.src_nid, dist);
+			}
+
+			/* Only consider nodes where both task and groups benefit */
+			taskimp = task_weight(p, nid, dist) - taskweight;
+			groupimp = group_weight(p, nid, dist) - groupweight;
+			if (taskimp < 0 && groupimp < 0)
+				continue;
+
+			env.dist = dist;
+			env.dst_nid = nid;
+			update_numa_stats(&env, &env.dst_stats, env.dst_nid, true);
+			task_numa_find_cpu(&env, taskimp, groupimp);
+		}
+	}
+
+	/*
+	 * If the task is part of a workload that spans multiple NUMA nodes,
+	 * and is migrating into one of the workload's active nodes, remember
+	 * this node as the task's preferred numa node, so the workload can
+	 * settle down.
+	 * A task that migrated to a second choice node will be better off
+	 * trying for a better one later. Do not set the preferred node here.
+	 */
+	if (ng) {
+		if (env.best_cpu == -1)
+			nid = env.src_nid;
+		else
+			nid = cpu_to_node(env.best_cpu);
+
+		if (nid != p->numa_preferred_nid)
+			sched_setnuma(p, nid);
+	}
+
+	/* No better CPU than the current one was found. */
+	if (env.best_cpu == -1) {
+		trace_sched_stick_numa(p, env.src_cpu, NULL, -1);
+		return -EAGAIN;
+	}
+
+	best_rq = cpu_rq(env.best_cpu);
+	if (env.best_task == NULL) {
+		ret = migrate_task_to(p, env.best_cpu);
+		WRITE_ONCE(best_rq->numa_migrate_on, 0);
+		if (ret != 0)
+			trace_sched_stick_numa(p, env.src_cpu, NULL, env.best_cpu);
+		return ret;
+	}
+
+	ret = migrate_swap(p, env.best_task, env.best_cpu, env.src_cpu);
+	WRITE_ONCE(best_rq->numa_migrate_on, 0);
+
+	if (ret != 0)
+		trace_sched_stick_numa(p, env.src_cpu, env.best_task, env.best_cpu);
+	put_task_struct(env.best_task);
+	return ret;
+}
+
+/* Attempt to migrate a task to a CPU on the preferred node. */
+static void numa_migrate_preferred(struct task_struct *p)
+{
+	unsigned long interval = HZ;
+
+	/* This task has no NUMA fault statistics yet */
+	if (unlikely(p->numa_preferred_nid == NUMA_NO_NODE || !p->numa_faults))
+		return;
+
+	/* Periodically retry migrating the task to the preferred node */
+	interval = min(interval, msecs_to_jiffies(p->numa_scan_period) / 16);
+	p->numa_migrate_retry = jiffies + interval;
+
+	/* Success if task is already running on preferred CPU */
+	if (task_node(p) == p->numa_preferred_nid)
+		return;
+
+	/* Otherwise, try migrate to a CPU on the preferred node */
+	task_numa_migrate(p);
+}
+
+/*
+ * Find out how many nodes the workload is actively running on. Do this by
+ * tracking the nodes from which NUMA hinting faults are triggered. This can
+ * be different from the set of nodes where the workload's memory is currently
+ * located.
+ */
+static void numa_group_count_active_nodes(struct numa_group *numa_group)
+{
+	unsigned long faults, max_faults = 0;
+	int nid, active_nodes = 0;
+
+	for_each_node_state(nid, N_CPU) {
+		faults = group_faults_cpu(numa_group, nid);
+		if (faults > max_faults)
+			max_faults = faults;
+	}
+
+	for_each_node_state(nid, N_CPU) {
+		faults = group_faults_cpu(numa_group, nid);
+		if (faults * ACTIVE_NODE_FRACTION > max_faults)
+			active_nodes++;
+	}
+
+	numa_group->max_faults_cpu = max_faults;
+	numa_group->active_nodes = active_nodes;
+}
+
+/*
+ * When adapting the scan rate, the period is divided into NUMA_PERIOD_SLOTS
+ * increments. The more local the fault statistics are, the higher the scan
+ * period will be for the next scan window. If local/(local+remote) ratio is
+ * below NUMA_PERIOD_THRESHOLD (where range of ratio is 1..NUMA_PERIOD_SLOTS)
+ * the scan period will decrease. Aim for 70% local accesses.
+ */
+#define NUMA_PERIOD_SLOTS 10
+#define NUMA_PERIOD_THRESHOLD 7
+
+/*
+ * Increase the scan period (slow down scanning) if the majority of
+ * our memory is already on our local node, or if the majority of
+ * the page accesses are shared with other processes.
+ * Otherwise, decrease the scan period.
+ */
+static void update_task_scan_period(struct task_struct *p,
+			unsigned long shared, unsigned long private)
+{
+	unsigned int period_slot;
+	int lr_ratio, ps_ratio;
+	int diff;
+
+	unsigned long remote = p->numa_faults_locality[0];
+	unsigned long local = p->numa_faults_locality[1];
+
+	/*
+	 * If there were no record hinting faults then either the task is
+	 * completely idle or all activity is in areas that are not of interest
+	 * to automatic numa balancing. Related to that, if there were failed
+	 * migration then it implies we are migrating too quickly or the local
+	 * node is overloaded. In either case, scan slower
+	 */
+	if (local + shared == 0 || p->numa_faults_locality[2]) {
+		p->numa_scan_period = min(p->numa_scan_period_max,
+			p->numa_scan_period << 1);
+
+		p->mm->numa_next_scan = jiffies +
+			msecs_to_jiffies(p->numa_scan_period);
+
+		return;
+	}
+
+	/*
+	 * Prepare to scale scan period relative to the current period.
+	 *	 == NUMA_PERIOD_THRESHOLD scan period stays the same
+	 *       <  NUMA_PERIOD_THRESHOLD scan period decreases (scan faster)
+	 *	 >= NUMA_PERIOD_THRESHOLD scan period increases (scan slower)
+	 */
+	period_slot = DIV_ROUND_UP(p->numa_scan_period, NUMA_PERIOD_SLOTS);
+	lr_ratio = (local * NUMA_PERIOD_SLOTS) / (local + remote);
+	ps_ratio = (private * NUMA_PERIOD_SLOTS) / (private + shared);
+
+	if (ps_ratio >= NUMA_PERIOD_THRESHOLD) {
+		/*
+		 * Most memory accesses are local. There is no need to
+		 * do fast NUMA scanning, since memory is already local.
+		 */
+		int slot = ps_ratio - NUMA_PERIOD_THRESHOLD;
+		if (!slot)
+			slot = 1;
+		diff = slot * period_slot;
+	} else if (lr_ratio >= NUMA_PERIOD_THRESHOLD) {
+		/*
+		 * Most memory accesses are shared with other tasks.
+		 * There is no point in continuing fast NUMA scanning,
+		 * since other tasks may just move the memory elsewhere.
+		 */
+		int slot = lr_ratio - NUMA_PERIOD_THRESHOLD;
+		if (!slot)
+			slot = 1;
+		diff = slot * period_slot;
+	} else {
+		/*
+		 * Private memory faults exceed (SLOTS-THRESHOLD)/SLOTS,
+		 * yet they are not on the local NUMA node. Speed up
+		 * NUMA scanning to get the memory moved over.
+		 */
+		int ratio = max(lr_ratio, ps_ratio);
+		diff = -(NUMA_PERIOD_THRESHOLD - ratio) * period_slot;
+	}
+
+	p->numa_scan_period = clamp(p->numa_scan_period + diff,
+			task_scan_min(p), task_scan_max(p));
+	memset(p->numa_faults_locality, 0, sizeof(p->numa_faults_locality));
+}
+
+/*
+ * Get the fraction of time the task has been running since the last
+ * NUMA placement cycle. The scheduler keeps similar statistics, but
+ * decays those on a 32ms period, which is orders of magnitude off
+ * from the dozens-of-seconds NUMA balancing period. Use the scheduler
+ * stats only if the task is so new there are no NUMA statistics yet.
+ */
+static u64 numa_get_avg_runtime(struct task_struct *p, u64 *period)
+{
+	u64 runtime, delta, now;
+	/* Use the start of this time slice to avoid calculations. */
+	now = p->se.exec_start;
+	runtime = p->se.sum_exec_runtime;
+
+	if (p->last_task_numa_placement) {
+		delta = runtime - p->last_sum_exec_runtime;
+		*period = now - p->last_task_numa_placement;
+
+		/* Avoid time going backwards, prevent potential divide error: */
+		if (unlikely((s64)*period < 0))
+			*period = 0;
+	} else {
+		delta = p->se.avg.load_sum;
+		*period = LOAD_AVG_MAX;
+	}
+
+	p->last_sum_exec_runtime = runtime;
+	p->last_task_numa_placement = now;
+
+	return delta;
+}
+
+/*
+ * Determine the preferred nid for a task in a numa_group. This needs to
+ * be done in a way that produces consistent results with group_weight,
+ * otherwise workloads might not converge.
+ */
+static int preferred_group_nid(struct task_struct *p, int nid)
+{
+	nodemask_t nodes;
+	int dist;
+
+	/* Direct connections between all NUMA nodes. */
+	if (sched_numa_topology_type == NUMA_DIRECT)
+		return nid;
+
+	/*
+	 * On a system with glueless mesh NUMA topology, group_weight
+	 * scores nodes according to the number of NUMA hinting faults on
+	 * both the node itself, and on nearby nodes.
+	 */
+	if (sched_numa_topology_type == NUMA_GLUELESS_MESH) {
+		unsigned long score, max_score = 0;
+		int node, max_node = nid;
+
+		dist = sched_max_numa_distance;
+
+		for_each_node_state(node, N_CPU) {
+			score = group_weight(p, node, dist);
+			if (score > max_score) {
+				max_score = score;
+				max_node = node;
+			}
+		}
+		return max_node;
+	}
+
+	/*
+	 * Finding the preferred nid in a system with NUMA backplane
+	 * interconnect topology is more involved. The goal is to locate
+	 * tasks from numa_groups near each other in the system, and
+	 * untangle workloads from different sides of the system. This requires
+	 * searching down the hierarchy of node groups, recursively searching
+	 * inside the highest scoring group of nodes. The nodemask tricks
+	 * keep the complexity of the search down.
+	 */
+	nodes = node_states[N_CPU];
+	for (dist = sched_max_numa_distance; dist > LOCAL_DISTANCE; dist--) {
+		unsigned long max_faults = 0;
+		nodemask_t max_group = NODE_MASK_NONE;
+		int a, b;
+
+		/* Are there nodes at this distance from each other? */
+		if (!find_numa_distance(dist))
+			continue;
+
+		for_each_node_mask(a, nodes) {
+			unsigned long faults = 0;
+			nodemask_t this_group;
+			nodes_clear(this_group);
+
+			/* Sum group's NUMA faults; includes a==b case. */
+			for_each_node_mask(b, nodes) {
+				if (node_distance(a, b) < dist) {
+					faults += group_faults(p, b);
+					node_set(b, this_group);
+					node_clear(b, nodes);
+				}
+			}
+
+			/* Remember the top group. */
+			if (faults > max_faults) {
+				max_faults = faults;
+				max_group = this_group;
+				/*
+				 * subtle: at the smallest distance there is
+				 * just one node left in each "group", the
+				 * winner is the preferred nid.
+				 */
+				nid = a;
+			}
+		}
+		/* Next round, evaluate the nodes within max_group. */
+		if (!max_faults)
+			break;
+		nodes = max_group;
+	}
+	return nid;
+}
+
+static void task_numa_placement(struct task_struct *p)
+{
+	int seq, nid, max_nid = NUMA_NO_NODE;
+	unsigned long max_faults = 0;
+	unsigned long fault_types[2] = { 0, 0 };
+	unsigned long total_faults;
+	u64 runtime, period;
+	spinlock_t *group_lock = NULL;
+	struct numa_group *ng;
+
+	/*
+	 * The p->mm->numa_scan_seq field gets updated without
+	 * exclusive access. Use READ_ONCE() here to ensure
+	 * that the field is read in a single access:
+	 */
+	seq = READ_ONCE(p->mm->numa_scan_seq);
+	if (p->numa_scan_seq == seq)
+		return;
+	p->numa_scan_seq = seq;
+	p->numa_scan_period_max = task_scan_max(p);
+
+	total_faults = p->numa_faults_locality[0] +
+		       p->numa_faults_locality[1];
+	runtime = numa_get_avg_runtime(p, &period);
+
+	/* If the task is part of a group prevent parallel updates to group stats */
+	ng = deref_curr_numa_group(p);
+	if (ng) {
+		group_lock = &ng->lock;
+		spin_lock_irq(group_lock);
+	}
+
+	/* Find the node with the highest number of faults */
+	for_each_online_node(nid) {
+		/* Keep track of the offsets in numa_faults array */
+		int mem_idx, membuf_idx, cpu_idx, cpubuf_idx;
+		unsigned long faults = 0, group_faults = 0;
+		int priv;
+
+		for (priv = 0; priv < NR_NUMA_HINT_FAULT_TYPES; priv++) {
+			long diff, f_diff, f_weight;
+
+			mem_idx = task_faults_idx(NUMA_MEM, nid, priv);
+			membuf_idx = task_faults_idx(NUMA_MEMBUF, nid, priv);
+			cpu_idx = task_faults_idx(NUMA_CPU, nid, priv);
+			cpubuf_idx = task_faults_idx(NUMA_CPUBUF, nid, priv);
+
+			/* Decay existing window, copy faults since last scan */
+			diff = p->numa_faults[membuf_idx] - p->numa_faults[mem_idx] / 2;
+			fault_types[priv] += p->numa_faults[membuf_idx];
+			p->numa_faults[membuf_idx] = 0;
+
+			/*
+			 * Normalize the faults_from, so all tasks in a group
+			 * count according to CPU use, instead of by the raw
+			 * number of faults. Tasks with little runtime have
+			 * little over-all impact on throughput, and thus their
+			 * faults are less important.
+			 */
+			f_weight = div64_u64(runtime << 16, period + 1);
+			f_weight = (f_weight * p->numa_faults[cpubuf_idx]) /
+				   (total_faults + 1);
+			f_diff = f_weight - p->numa_faults[cpu_idx] / 2;
+			p->numa_faults[cpubuf_idx] = 0;
+
+			p->numa_faults[mem_idx] += diff;
+			p->numa_faults[cpu_idx] += f_diff;
+			faults += p->numa_faults[mem_idx];
+			p->total_numa_faults += diff;
+			if (ng) {
+				/*
+				 * safe because we can only change our own group
+				 *
+				 * mem_idx represents the offset for a given
+				 * nid and priv in a specific region because it
+				 * is at the beginning of the numa_faults array.
+				 */
+				ng->faults[mem_idx] += diff;
+				ng->faults[cpu_idx] += f_diff;
+				ng->total_faults += diff;
+				group_faults += ng->faults[mem_idx];
+			}
+		}
+
+		if (!ng) {
+			if (faults > max_faults) {
+				max_faults = faults;
+				max_nid = nid;
+			}
+		} else if (group_faults > max_faults) {
+			max_faults = group_faults;
+			max_nid = nid;
+		}
+	}
+
+	/* Cannot migrate task to CPU-less node */
+	if (max_nid != NUMA_NO_NODE && !node_state(max_nid, N_CPU)) {
+		int near_nid = max_nid;
+		int distance, near_distance = INT_MAX;
+
+		for_each_node_state(nid, N_CPU) {
+			distance = node_distance(max_nid, nid);
+			if (distance < near_distance) {
+				near_nid = nid;
+				near_distance = distance;
+			}
+		}
+		max_nid = near_nid;
+	}
+
+	if (ng) {
+		numa_group_count_active_nodes(ng);
+		spin_unlock_irq(group_lock);
+		max_nid = preferred_group_nid(p, max_nid);
+	}
+
+	if (max_faults) {
+		/* Set the new preferred node */
+		if (max_nid != p->numa_preferred_nid)
+			sched_setnuma(p, max_nid);
+	}
+
+	update_task_scan_period(p, fault_types[0], fault_types[1]);
+}
+
+static inline int get_numa_group(struct numa_group *grp)
+{
+	return refcount_inc_not_zero(&grp->refcount);
+}
+
+static inline void put_numa_group(struct numa_group *grp)
+{
+	if (refcount_dec_and_test(&grp->refcount))
+		kfree_rcu(grp, rcu);
+}
+
+static void task_numa_group(struct task_struct *p, int cpupid, int flags,
+			int *priv)
+{
+	struct numa_group *grp, *my_grp;
+	struct task_struct *tsk;
+	bool join = false;
+	int cpu = cpupid_to_cpu(cpupid);
+	int i;
+
+	if (unlikely(!deref_curr_numa_group(p))) {
+		unsigned int size = sizeof(struct numa_group) +
+				    NR_NUMA_HINT_FAULT_STATS *
+				    nr_node_ids * sizeof(unsigned long);
+
+		grp = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
+		if (!grp)
+			return;
+
+		refcount_set(&grp->refcount, 1);
+		grp->active_nodes = 1;
+		grp->max_faults_cpu = 0;
+		spin_lock_init(&grp->lock);
+		grp->gid = p->pid;
+
+		for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++)
+			grp->faults[i] = p->numa_faults[i];
+
+		grp->total_faults = p->total_numa_faults;
+
+		grp->nr_tasks++;
+		rcu_assign_pointer(p->numa_group, grp);
+	}
+
+	rcu_read_lock();
+	tsk = READ_ONCE(cpu_rq(cpu)->curr);
+
+	if (!cpupid_match_pid(tsk, cpupid))
+		goto no_join;
+
+	grp = rcu_dereference(tsk->numa_group);
+	if (!grp)
+		goto no_join;
+
+	my_grp = deref_curr_numa_group(p);
+	if (grp == my_grp)
+		goto no_join;
+
+	/*
+	 * Only join the other group if its bigger; if we're the bigger group,
+	 * the other task will join us.
+	 */
+	if (my_grp->nr_tasks > grp->nr_tasks)
+		goto no_join;
+
+	/*
+	 * Tie-break on the grp address.
+	 */
+	if (my_grp->nr_tasks == grp->nr_tasks && my_grp > grp)
+		goto no_join;
+
+	/* Always join threads in the same process. */
+	if (tsk->mm == current->mm)
+		join = true;
+
+	/* Simple filter to avoid false positives due to PID collisions */
+	if (flags & TNF_SHARED)
+		join = true;
+
+	/* Update priv based on whether false sharing was detected */
+	*priv = !join;
+
+	if (join && !get_numa_group(grp))
+		goto no_join;
+
+	rcu_read_unlock();
+
+	if (!join)
+		return;
+
+	WARN_ON_ONCE(irqs_disabled());
+	double_lock_irq(&my_grp->lock, &grp->lock);
+
+	for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++) {
+		my_grp->faults[i] -= p->numa_faults[i];
+		grp->faults[i] += p->numa_faults[i];
+	}
+	my_grp->total_faults -= p->total_numa_faults;
+	grp->total_faults += p->total_numa_faults;
+
+	my_grp->nr_tasks--;
+	grp->nr_tasks++;
+
+	spin_unlock(&my_grp->lock);
+	spin_unlock_irq(&grp->lock);
+
+	rcu_assign_pointer(p->numa_group, grp);
+
+	put_numa_group(my_grp);
+	return;
+
+no_join:
+	rcu_read_unlock();
+	return;
+}
+
+/*
+ * Get rid of NUMA statistics associated with a task (either current or dead).
+ * If @final is set, the task is dead and has reached refcount zero, so we can
+ * safely free all relevant data structures. Otherwise, there might be
+ * concurrent reads from places like load balancing and procfs, and we should
+ * reset the data back to default state without freeing ->numa_faults.
+ */
+void task_numa_free(struct task_struct *p, bool final)
+{
+	/* safe: p either is current or is being freed by current */
+	struct numa_group *grp = rcu_dereference_raw(p->numa_group);
+	unsigned long *numa_faults = p->numa_faults;
+	unsigned long flags;
+	int i;
+
+	if (!numa_faults)
+		return;
+
+	if (grp) {
+		spin_lock_irqsave(&grp->lock, flags);
+		for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++)
+			grp->faults[i] -= p->numa_faults[i];
+		grp->total_faults -= p->total_numa_faults;
+
+		grp->nr_tasks--;
+		spin_unlock_irqrestore(&grp->lock, flags);
+		RCU_INIT_POINTER(p->numa_group, NULL);
+		put_numa_group(grp);
+	}
+
+	if (final) {
+		p->numa_faults = NULL;
+		kfree(numa_faults);
+	} else {
+		p->total_numa_faults = 0;
+		for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++)
+			numa_faults[i] = 0;
+	}
+}
+
+/*
+ * Got a PROT_NONE fault for a page on @node.
+ */
+void task_numa_fault(int last_cpupid, int mem_node, int pages, int flags)
+{
+	struct task_struct *p = current;
+	bool migrated = flags & TNF_MIGRATED;
+	int cpu_node = task_node(current);
+	int local = !!(flags & TNF_FAULT_LOCAL);
+	struct numa_group *ng;
+	int priv;
+
+	if (!static_branch_likely(&sched_numa_balancing))
+		return;
+
+	/* for example, ksmd faulting in a user's mm */
+	if (!p->mm)
+		return;
+
+	/*
+	 * NUMA faults statistics are unnecessary for the slow memory
+	 * node for memory tiering mode.
+	 */
+	if (!node_is_toptier(mem_node) &&
+	    (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING ||
+	     !cpupid_valid(last_cpupid)))
+		return;
+
+	/* Allocate buffer to track faults on a per-node basis */
+	if (unlikely(!p->numa_faults)) {
+		int size = sizeof(*p->numa_faults) *
+			   NR_NUMA_HINT_FAULT_BUCKETS * nr_node_ids;
+
+		p->numa_faults = kzalloc(size, GFP_KERNEL|__GFP_NOWARN);
+		if (!p->numa_faults)
+			return;
+
+		p->total_numa_faults = 0;
+		memset(p->numa_faults_locality, 0, sizeof(p->numa_faults_locality));
+	}
+
+	/*
+	 * First accesses are treated as private, otherwise consider accesses
+	 * to be private if the accessing pid has not changed
+	 */
+	if (unlikely(last_cpupid == (-1 & LAST_CPUPID_MASK))) {
+		priv = 1;
+	} else {
+		priv = cpupid_match_pid(p, last_cpupid);
+		if (!priv && !(flags & TNF_NO_GROUP))
+			task_numa_group(p, last_cpupid, flags, &priv);
+	}
+
+	/*
+	 * If a workload spans multiple NUMA nodes, a shared fault that
+	 * occurs wholly within the set of nodes that the workload is
+	 * actively using should be counted as local. This allows the
+	 * scan rate to slow down when a workload has settled down.
+	 */
+	ng = deref_curr_numa_group(p);
+	if (!priv && !local && ng && ng->active_nodes > 1 &&
+				numa_is_active_node(cpu_node, ng) &&
+				numa_is_active_node(mem_node, ng))
+		local = 1;
+
+	/*
+	 * Retry to migrate task to preferred node periodically, in case it
+	 * previously failed, or the scheduler moved us.
+	 */
+	if (time_after(jiffies, p->numa_migrate_retry)) {
+		task_numa_placement(p);
+		numa_migrate_preferred(p);
+	}
+
+	if (migrated)
+		p->numa_pages_migrated += pages;
+	if (flags & TNF_MIGRATE_FAIL)
+		p->numa_faults_locality[2] += pages;
+
+	p->numa_faults[task_faults_idx(NUMA_MEMBUF, mem_node, priv)] += pages;
+	p->numa_faults[task_faults_idx(NUMA_CPUBUF, cpu_node, priv)] += pages;
+	p->numa_faults_locality[local] += pages;
+}
+
+static void reset_ptenuma_scan(struct task_struct *p)
+{
+	/*
+	 * We only did a read acquisition of the mmap sem, so
+	 * p->mm->numa_scan_seq is written to without exclusive access
+	 * and the update is not guaranteed to be atomic. That's not
+	 * much of an issue though, since this is just used for
+	 * statistical sampling. Use READ_ONCE/WRITE_ONCE, which are not
+	 * expensive, to avoid any form of compiler optimizations:
+	 */
+	WRITE_ONCE(p->mm->numa_scan_seq, READ_ONCE(p->mm->numa_scan_seq) + 1);
+	p->mm->numa_scan_offset = 0;
+}
+
+static bool vma_is_accessed(struct vm_area_struct *vma)
+{
+	unsigned long pids;
+	/*
+	 * Allow unconditional access first two times, so that all the (pages)
+	 * of VMAs get prot_none fault introduced irrespective of accesses.
+	 * This is also done to avoid any side effect of task scanning
+	 * amplifying the unfairness of disjoint set of VMAs' access.
+	 */
+	if (READ_ONCE(current->mm->numa_scan_seq) < 2)
+		return true;
+
+	pids = vma->numab_state->access_pids[0] | vma->numab_state->access_pids[1];
+	return test_bit(hash_32(current->pid, ilog2(BITS_PER_LONG)), &pids);
+}
+
+#define VMA_PID_RESET_PERIOD (4 * sysctl_numa_balancing_scan_delay)
+
+/*
+ * The expensive part of numa migration is done from task_work context.
+ * Triggered from task_tick_numa().
+ */
+static void task_numa_work(struct callback_head *work)
+{
+	unsigned long migrate, next_scan, now = jiffies;
+	struct task_struct *p = current;
+	struct mm_struct *mm = p->mm;
+	u64 runtime = p->se.sum_exec_runtime;
+	struct vm_area_struct *vma;
+	unsigned long start, end;
+	unsigned long nr_pte_updates = 0;
+	long pages, virtpages;
+	struct vma_iterator vmi;
+
+	SCHED_WARN_ON(p != container_of(work, struct task_struct, numa_work));
+
+	work->next = work;
+	/*
+	 * Who cares about NUMA placement when they're dying.
+	 *
+	 * NOTE: make sure not to dereference p->mm before this check,
+	 * exit_task_work() happens _after_ exit_mm() so we could be called
+	 * without p->mm even though we still had it when we enqueued this
+	 * work.
+	 */
+	if (p->flags & PF_EXITING)
+		return;
+
+	if (!mm->numa_next_scan) {
+		mm->numa_next_scan = now +
+			msecs_to_jiffies(sysctl_numa_balancing_scan_delay);
+	}
+
+	/*
+	 * Enforce maximal scan/migration frequency..
+	 */
+	migrate = mm->numa_next_scan;
+	if (time_before(now, migrate))
+		return;
+
+	if (p->numa_scan_period == 0) {
+		p->numa_scan_period_max = task_scan_max(p);
+		p->numa_scan_period = task_scan_start(p);
+	}
+
+	next_scan = now + msecs_to_jiffies(p->numa_scan_period);
+	if (!try_cmpxchg(&mm->numa_next_scan, &migrate, next_scan))
+		return;
+
+	/*
+	 * Delay this task enough that another task of this mm will likely win
+	 * the next time around.
+	 */
+	p->node_stamp += 2 * TICK_NSEC;
+
+	start = mm->numa_scan_offset;
+	pages = sysctl_numa_balancing_scan_size;
+	pages <<= 20 - PAGE_SHIFT; /* MB in pages */
+	virtpages = pages * 8;	   /* Scan up to this much virtual space */
+	if (!pages)
+		return;
+
+
+	if (!mmap_read_trylock(mm))
+		return;
+	vma_iter_init(&vmi, mm, start);
+	vma = vma_next(&vmi);
+	if (!vma) {
+		reset_ptenuma_scan(p);
+		start = 0;
+		vma_iter_set(&vmi, start);
+		vma = vma_next(&vmi);
+	}
+
+	do {
+		if (!vma_migratable(vma) || !vma_policy_mof(vma) ||
+			is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_MIXEDMAP)) {
+			continue;
+		}
+
+		/*
+		 * Shared library pages mapped by multiple processes are not
+		 * migrated as it is expected they are cache replicated. Avoid
+		 * hinting faults in read-only file-backed mappings or the vdso
+		 * as migrating the pages will be of marginal benefit.
+		 */
+		if (!vma->vm_mm ||
+		    (vma->vm_file && (vma->vm_flags & (VM_READ|VM_WRITE)) == (VM_READ)))
+			continue;
+
+		/*
+		 * Skip inaccessible VMAs to avoid any confusion between
+		 * PROT_NONE and NUMA hinting ptes
+		 */
+		if (!vma_is_accessible(vma))
+			continue;
+
+		/* Initialise new per-VMA NUMAB state. */
+		if (!vma->numab_state) {
+			vma->numab_state = kzalloc(sizeof(struct vma_numab_state),
+				GFP_KERNEL);
+			if (!vma->numab_state)
+				continue;
+
+			vma->numab_state->next_scan = now +
+				msecs_to_jiffies(sysctl_numa_balancing_scan_delay);
+
+			/* Reset happens after 4 times scan delay of scan start */
+			vma->numab_state->next_pid_reset =  vma->numab_state->next_scan +
+				msecs_to_jiffies(VMA_PID_RESET_PERIOD);
+		}
+
+		/*
+		 * Scanning the VMA's of short lived tasks add more overhead. So
+		 * delay the scan for new VMAs.
+		 */
+		if (mm->numa_scan_seq && time_before(jiffies,
+						vma->numab_state->next_scan))
+			continue;
+
+		/* Do not scan the VMA if task has not accessed */
+		if (!vma_is_accessed(vma))
+			continue;
+
+		/*
+		 * RESET access PIDs regularly for old VMAs. Resetting after checking
+		 * vma for recent access to avoid clearing PID info before access..
+		 */
+		if (mm->numa_scan_seq &&
+				time_after(jiffies, vma->numab_state->next_pid_reset)) {
+			vma->numab_state->next_pid_reset = vma->numab_state->next_pid_reset +
+				msecs_to_jiffies(VMA_PID_RESET_PERIOD);
+			vma->numab_state->access_pids[0] = READ_ONCE(vma->numab_state->access_pids[1]);
+			vma->numab_state->access_pids[1] = 0;
+		}
+
+		do {
+			start = max(start, vma->vm_start);
+			end = ALIGN(start + (pages << PAGE_SHIFT), HPAGE_SIZE);
+			end = min(end, vma->vm_end);
+			nr_pte_updates = change_prot_numa(vma, start, end);
+
+			/*
+			 * Try to scan sysctl_numa_balancing_size worth of
+			 * hpages that have at least one present PTE that
+			 * is not already pte-numa. If the VMA contains
+			 * areas that are unused or already full of prot_numa
+			 * PTEs, scan up to virtpages, to skip through those
+			 * areas faster.
+			 */
+			if (nr_pte_updates)
+				pages -= (end - start) >> PAGE_SHIFT;
+			virtpages -= (end - start) >> PAGE_SHIFT;
+
+			start = end;
+			if (pages <= 0 || virtpages <= 0)
+				goto out;
+
+			cond_resched();
+		} while (end != vma->vm_end);
+	} for_each_vma(vmi, vma);
+
+out:
+	/*
+	 * It is possible to reach the end of the VMA list but the last few
+	 * VMAs are not guaranteed to the vma_migratable. If they are not, we
+	 * would find the !migratable VMA on the next scan but not reset the
+	 * scanner to the start so check it now.
+	 */
+	if (vma)
+		mm->numa_scan_offset = start;
+	else
+		reset_ptenuma_scan(p);
+	mmap_read_unlock(mm);
+
+	/*
+	 * Make sure tasks use at least 32x as much time to run other code
+	 * than they used here, to limit NUMA PTE scanning overhead to 3% max.
+	 * Usually update_task_scan_period slows down scanning enough; on an
+	 * overloaded system we need to limit overhead on a per task basis.
+	 */
+	if (unlikely(p->se.sum_exec_runtime != runtime)) {
+		u64 diff = p->se.sum_exec_runtime - runtime;
+		p->node_stamp += 32 * diff;
+	}
+}
+
+void init_numa_balancing(unsigned long clone_flags, struct task_struct *p)
+{
+	int mm_users = 0;
+	struct mm_struct *mm = p->mm;
+
+	if (mm) {
+		mm_users = atomic_read(&mm->mm_users);
+		if (mm_users == 1) {
+			mm->numa_next_scan = jiffies + msecs_to_jiffies(sysctl_numa_balancing_scan_delay);
+			mm->numa_scan_seq = 0;
+		}
+	}
+	p->node_stamp			= 0;
+	p->numa_scan_seq		= mm ? mm->numa_scan_seq : 0;
+	p->numa_scan_period		= sysctl_numa_balancing_scan_delay;
+	p->numa_migrate_retry		= 0;
+	/* Protect against double add, see task_tick_numa and task_numa_work */
+	p->numa_work.next		= &p->numa_work;
+	p->numa_faults			= NULL;
+	p->numa_pages_migrated		= 0;
+	p->total_numa_faults		= 0;
+	RCU_INIT_POINTER(p->numa_group, NULL);
+	p->last_task_numa_placement	= 0;
+	p->last_sum_exec_runtime	= 0;
+
+	init_task_work(&p->numa_work, task_numa_work);
+
+	/* New address space, reset the preferred nid */
+	if (!(clone_flags & CLONE_VM)) {
+		p->numa_preferred_nid = NUMA_NO_NODE;
+		return;
+	}
+
+	/*
+	 * New thread, keep existing numa_preferred_nid which should be copied
+	 * already by arch_dup_task_struct but stagger when scans start.
+	 */
+	if (mm) {
+		unsigned int delay;
+
+		delay = min_t(unsigned int, task_scan_max(current),
+			current->numa_scan_period * mm_users * NSEC_PER_MSEC);
+		delay += 2 * TICK_NSEC;
+		p->node_stamp = delay;
+	}
+}
+
+/*
+ * Drive the periodic memory faults..
+ */
+static void task_tick_numa(struct rq *rq, struct task_struct *curr)
+{
+	struct callback_head *work = &curr->numa_work;
+	u64 period, now;
+
+	/*
+	 * We don't care about NUMA placement if we don't have memory.
+	 */
+	if (!curr->mm || (curr->flags & (PF_EXITING | PF_KTHREAD)) || work->next != work)
+		return;
+
+	/*
+	 * Using runtime rather than walltime has the dual advantage that
+	 * we (mostly) drive the selection from busy threads and that the
+	 * task needs to have done some actual work before we bother with
+	 * NUMA placement.
+	 */
+	now = curr->se.sum_exec_runtime;
+	period = (u64)curr->numa_scan_period * NSEC_PER_MSEC;
+
+	if (now > curr->node_stamp + period) {
+		if (!curr->node_stamp)
+			curr->numa_scan_period = task_scan_start(curr);
+		curr->node_stamp += period;
+
+		if (!time_before(jiffies, curr->mm->numa_next_scan))
+			task_work_add(curr, work, TWA_RESUME);
+	}
+}
+
+static void update_scan_period(struct task_struct *p, int new_cpu)
+{
+	int src_nid = cpu_to_node(task_cpu(p));
+	int dst_nid = cpu_to_node(new_cpu);
+
+	if (!static_branch_likely(&sched_numa_balancing))
+		return;
+
+	if (!p->mm || !p->numa_faults || (p->flags & PF_EXITING))
+		return;
+
+	if (src_nid == dst_nid)
+		return;
+
+	/*
+	 * Allow resets if faults have been trapped before one scan
+	 * has completed. This is most likely due to a new task that
+	 * is pulled cross-node due to wakeups or load balancing.
+	 */
+	if (p->numa_scan_seq) {
+		/*
+		 * Avoid scan adjustments if moving to the preferred
+		 * node or if the task was not previously running on
+		 * the preferred node.
+		 */
+		if (dst_nid == p->numa_preferred_nid ||
+		    (p->numa_preferred_nid != NUMA_NO_NODE &&
+			src_nid != p->numa_preferred_nid))
+			return;
+	}
+
+	p->numa_scan_period = task_scan_start(p);
+}
+
+#else
+static void task_tick_numa(struct rq *rq, struct task_struct *curr)
+{
+}
+
+static inline void account_numa_enqueue(struct rq *rq, struct task_struct *p)
+{
+}
+
+static inline void account_numa_dequeue(struct rq *rq, struct task_struct *p)
+{
+}
+
+static inline void update_scan_period(struct task_struct *p, int new_cpu)
+{
+}
+
+#endif /* CONFIG_NUMA_BALANCING */
+
+static void
+account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	update_load_add(&cfs_rq->load, se->load.weight);
+#ifdef CONFIG_SMP
+	if (entity_is_task(se)) {
+		struct rq *rq = rq_of(cfs_rq);
+
+		account_numa_enqueue(rq, task_of(se));
+		list_add(&se->group_node, &rq->cfs_tasks);
+	}
+#endif
+	cfs_rq->nr_running++;
+	if (se_is_idle(se))
+		cfs_rq->idle_nr_running++;
+}
+
+static void
+account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	update_load_sub(&cfs_rq->load, se->load.weight);
+#ifdef CONFIG_SMP
+	if (entity_is_task(se)) {
+		account_numa_dequeue(rq_of(cfs_rq), task_of(se));
+		list_del_init(&se->group_node);
+	}
+#endif
+	cfs_rq->nr_running--;
+	if (se_is_idle(se))
+		cfs_rq->idle_nr_running--;
+}
+
+/*
+ * Signed add and clamp on underflow.
+ *
+ * Explicitly do a load-store to ensure the intermediate value never hits
+ * memory. This allows lockless observations without ever seeing the negative
+ * values.
+ */
+#define add_positive(_ptr, _val) do {                           \
+	typeof(_ptr) ptr = (_ptr);                              \
+	typeof(_val) val = (_val);                              \
+	typeof(*ptr) res, var = READ_ONCE(*ptr);                \
+								\
+	res = var + val;                                        \
+								\
+	if (val < 0 && res > var)                               \
+		res = 0;                                        \
+								\
+	WRITE_ONCE(*ptr, res);                                  \
+} while (0)
+
+/*
+ * Unsigned subtract and clamp on underflow.
+ *
+ * Explicitly do a load-store to ensure the intermediate value never hits
+ * memory. This allows lockless observations without ever seeing the negative
+ * values.
+ */
+#define sub_positive(_ptr, _val) do {				\
+	typeof(_ptr) ptr = (_ptr);				\
+	typeof(*ptr) val = (_val);				\
+	typeof(*ptr) res, var = READ_ONCE(*ptr);		\
+	res = var - val;					\
+	if (res > var)						\
+		res = 0;					\
+	WRITE_ONCE(*ptr, res);					\
+} while (0)
+
+/*
+ * Remove and clamp on negative, from a local variable.
+ *
+ * A variant of sub_positive(), which does not use explicit load-store
+ * and is thus optimized for local variable updates.
+ */
+#define lsub_positive(_ptr, _val) do {				\
+	typeof(_ptr) ptr = (_ptr);				\
+	*ptr -= min_t(typeof(*ptr), *ptr, _val);		\
+} while (0)
+
+#ifdef CONFIG_SMP
+static inline void
+enqueue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	cfs_rq->avg.load_avg += se->avg.load_avg;
+	cfs_rq->avg.load_sum += se_weight(se) * se->avg.load_sum;
+}
+
+static inline void
+dequeue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	sub_positive(&cfs_rq->avg.load_avg, se->avg.load_avg);
+	sub_positive(&cfs_rq->avg.load_sum, se_weight(se) * se->avg.load_sum);
+	/* See update_cfs_rq_load_avg() */
+	cfs_rq->avg.load_sum = max_t(u32, cfs_rq->avg.load_sum,
+					  cfs_rq->avg.load_avg * PELT_MIN_DIVIDER);
+}
+#else
+static inline void
+enqueue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) { }
+static inline void
+dequeue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) { }
+#endif
+
+static void reweight_eevdf(struct cfs_rq *cfs_rq, struct sched_entity *se,
+			   unsigned long weight)
+{
+	unsigned long old_weight = se->load.weight;
+	u64 avruntime = avg_vruntime(cfs_rq);
+	s64 vlag, vslice;
+
+	/*
+	 * VRUNTIME
+	 * ========
+	 *
+	 * COROLLARY #1: The virtual runtime of the entity needs to be
+	 * adjusted if re-weight at !0-lag point.
+	 *
+	 * Proof: For contradiction assume this is not true, so we can
+	 * re-weight without changing vruntime at !0-lag point.
+	 *
+	 *             Weight	VRuntime   Avg-VRuntime
+	 *     before    w          v            V
+	 *      after    w'         v'           V'
+	 *
+	 * Since lag needs to be preserved through re-weight:
+	 *
+	 *	lag = (V - v)*w = (V'- v')*w', where v = v'
+	 *	==>	V' = (V - v)*w/w' + v		(1)
+	 *
+	 * Let W be the total weight of the entities before reweight,
+	 * since V' is the new weighted average of entities:
+	 *
+	 *	V' = (WV + w'v - wv) / (W + w' - w)	(2)
+	 *
+	 * by using (1) & (2) we obtain:
+	 *
+	 *	(WV + w'v - wv) / (W + w' - w) = (V - v)*w/w' + v
+	 *	==> (WV-Wv+Wv+w'v-wv)/(W+w'-w) = (V - v)*w/w' + v
+	 *	==> (WV - Wv)/(W + w' - w) + v = (V - v)*w/w' + v
+	 *	==>	(V - v)*W/(W + w' - w) = (V - v)*w/w' (3)
+	 *
+	 * Since we are doing at !0-lag point which means V != v, we
+	 * can simplify (3):
+	 *
+	 *	==>	W / (W + w' - w) = w / w'
+	 *	==>	Ww' = Ww + ww' - ww
+	 *	==>	W * (w' - w) = w * (w' - w)
+	 *	==>	W = w	(re-weight indicates w' != w)
+	 *
+	 * So the cfs_rq contains only one entity, hence vruntime of
+	 * the entity @v should always equal to the cfs_rq's weighted
+	 * average vruntime @V, which means we will always re-weight
+	 * at 0-lag point, thus breach assumption. Proof completed.
+	 *
+	 *
+	 * COROLLARY #2: Re-weight does NOT affect weighted average
+	 * vruntime of all the entities.
+	 *
+	 * Proof: According to corollary #1, Eq. (1) should be:
+	 *
+	 *	(V - v)*w = (V' - v')*w'
+	 *	==>    v' = V' - (V - v)*w/w'		(4)
+	 *
+	 * According to the weighted average formula, we have:
+	 *
+	 *	V' = (WV - wv + w'v') / (W - w + w')
+	 *	   = (WV - wv + w'(V' - (V - v)w/w')) / (W - w + w')
+	 *	   = (WV - wv + w'V' - Vw + wv) / (W - w + w')
+	 *	   = (WV + w'V' - Vw) / (W - w + w')
+	 *
+	 *	==>  V'*(W - w + w') = WV + w'V' - Vw
+	 *	==>	V' * (W - w) = (W - w) * V	(5)
+	 *
+	 * If the entity is the only one in the cfs_rq, then reweight
+	 * always occurs at 0-lag point, so V won't change. Or else
+	 * there are other entities, hence W != w, then Eq. (5) turns
+	 * into V' = V. So V won't change in either case, proof done.
+	 *
+	 *
+	 * So according to corollary #1 & #2, the effect of re-weight
+	 * on vruntime should be:
+	 *
+	 *	v' = V' - (V - v) * w / w'		(4)
+	 *	   = V  - (V - v) * w / w'
+	 *	   = V  - vl * w / w'
+	 *	   = V  - vl'
+	 */
+	if (avruntime != se->vruntime) {
+		vlag = (s64)(avruntime - se->vruntime);
+		vlag = div_s64(vlag * old_weight, weight);
+		se->vruntime = avruntime - vlag;
+	}
+
+	/*
+	 * DEADLINE
+	 * ========
+	 *
+	 * When the weight changes, the virtual time slope changes and
+	 * we should adjust the relative virtual deadline accordingly.
+	 *
+	 *	d' = v' + (d - v)*w/w'
+	 *	   = V' - (V - v)*w/w' + (d - v)*w/w'
+	 *	   = V  - (V - v)*w/w' + (d - v)*w/w'
+	 *	   = V  + (d - V)*w/w'
+	 */
+	vslice = (s64)(se->deadline - avruntime);
+	vslice = div_s64(vslice * old_weight, weight);
+	se->deadline = avruntime + vslice;
+}
+
+static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
+			    unsigned long weight)
+{
+	bool curr = cfs_rq->curr == se;
+
+	if (se->on_rq) {
+		/* commit outstanding execution time */
+		if (curr)
+			update_curr(cfs_rq);
+		else
+			__dequeue_entity(cfs_rq, se);
+		update_load_sub(&cfs_rq->load, se->load.weight);
+	}
+	dequeue_load_avg(cfs_rq, se);
+
+	if (!se->on_rq) {
+		/*
+		 * Because we keep se->vlag = V - v_i, while: lag_i = w_i*(V - v_i),
+		 * we need to scale se->vlag when w_i changes.
+		 */
+		se->vlag = div_s64(se->vlag * se->load.weight, weight);
+	} else {
+		reweight_eevdf(cfs_rq, se, weight);
+	}
+
+	update_load_set(&se->load, weight);
+
+#ifdef CONFIG_SMP
+	do {
+		u32 divider = get_pelt_divider(&se->avg);
+
+		se->avg.load_avg = div_u64(se_weight(se) * se->avg.load_sum, divider);
+	} while (0);
+#endif
+
+	enqueue_load_avg(cfs_rq, se);
+	if (se->on_rq) {
+		update_load_add(&cfs_rq->load, se->load.weight);
+		if (!curr)
+			__enqueue_entity(cfs_rq, se);
+
+		/*
+		 * The entity's vruntime has been adjusted, so let's check
+		 * whether the rq-wide min_vruntime needs updated too. Since
+		 * the calculations above require stable min_vruntime rather
+		 * than up-to-date one, we do the update at the end of the
+		 * reweight process.
+		 */
+		update_min_vruntime(cfs_rq);
+	}
+}
+
+void reweight_task(struct task_struct *p, int prio)
+{
+	struct sched_entity *se = &p->se;
+	struct cfs_rq *cfs_rq = cfs_rq_of(se);
+	struct load_weight *load = &se->load;
+	unsigned long weight = scale_load(sched_prio_to_weight[prio]);
+
+	reweight_entity(cfs_rq, se, weight);
+	load->inv_weight = sched_prio_to_wmult[prio];
+}
+
+static inline int throttled_hierarchy(struct cfs_rq *cfs_rq);
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+#ifdef CONFIG_SMP
+/*
+ * All this does is approximate the hierarchical proportion which includes that
+ * global sum we all love to hate.
+ *
+ * That is, the weight of a group entity, is the proportional share of the
+ * group weight based on the group runqueue weights. That is:
+ *
+ *                     tg->weight * grq->load.weight
+ *   ge->load.weight = -----------------------------               (1)
+ *                       \Sum grq->load.weight
+ *
+ * Now, because computing that sum is prohibitively expensive to compute (been
+ * there, done that) we approximate it with this average stuff. The average
+ * moves slower and therefore the approximation is cheaper and more stable.
+ *
+ * So instead of the above, we substitute:
+ *
+ *   grq->load.weight -> grq->avg.load_avg                         (2)
+ *
+ * which yields the following:
+ *
+ *                     tg->weight * grq->avg.load_avg
+ *   ge->load.weight = ------------------------------              (3)
+ *                             tg->load_avg
+ *
+ * Where: tg->load_avg ~= \Sum grq->avg.load_avg
+ *
+ * That is shares_avg, and it is right (given the approximation (2)).
+ *
+ * The problem with it is that because the average is slow -- it was designed
+ * to be exactly that of course -- this leads to transients in boundary
+ * conditions. In specific, the case where the group was idle and we start the
+ * one task. It takes time for our CPU's grq->avg.load_avg to build up,
+ * yielding bad latency etc..
+ *
+ * Now, in that special case (1) reduces to:
+ *
+ *                     tg->weight * grq->load.weight
+ *   ge->load.weight = ----------------------------- = tg->weight   (4)
+ *                         grp->load.weight
+ *
+ * That is, the sum collapses because all other CPUs are idle; the UP scenario.
+ *
+ * So what we do is modify our approximation (3) to approach (4) in the (near)
+ * UP case, like:
+ *
+ *   ge->load.weight =
+ *
+ *              tg->weight * grq->load.weight
+ *     ---------------------------------------------------         (5)
+ *     tg->load_avg - grq->avg.load_avg + grq->load.weight
+ *
+ * But because grq->load.weight can drop to 0, resulting in a divide by zero,
+ * we need to use grq->avg.load_avg as its lower bound, which then gives:
+ *
+ *
+ *                     tg->weight * grq->load.weight
+ *   ge->load.weight = -----------------------------		   (6)
+ *                             tg_load_avg'
+ *
+ * Where:
+ *
+ *   tg_load_avg' = tg->load_avg - grq->avg.load_avg +
+ *                  max(grq->load.weight, grq->avg.load_avg)
+ *
+ * And that is shares_weight and is icky. In the (near) UP case it approaches
+ * (4) while in the normal case it approaches (3). It consistently
+ * overestimates the ge->load.weight and therefore:
+ *
+ *   \Sum ge->load.weight >= tg->weight
+ *
+ * hence icky!
+ */
+static long calc_group_shares(struct cfs_rq *cfs_rq)
+{
+	long tg_weight, tg_shares, load, shares;
+	struct task_group *tg = cfs_rq->tg;
+
+	tg_shares = READ_ONCE(tg->shares);
+
+	load = max(scale_load_down(cfs_rq->load.weight), cfs_rq->avg.load_avg);
+
+	tg_weight = atomic_long_read(&tg->load_avg);
+
+	/* Ensure tg_weight >= load */
+	tg_weight -= cfs_rq->tg_load_avg_contrib;
+	tg_weight += load;
+
+	shares = (tg_shares * load);
+	if (tg_weight)
+		shares /= tg_weight;
+
+	/*
+	 * MIN_SHARES has to be unscaled here to support per-CPU partitioning
+	 * of a group with small tg->shares value. It is a floor value which is
+	 * assigned as a minimum load.weight to the sched_entity representing
+	 * the group on a CPU.
+	 *
+	 * E.g. on 64-bit for a group with tg->shares of scale_load(15)=15*1024
+	 * on an 8-core system with 8 tasks each runnable on one CPU shares has
+	 * to be 15*1024*1/8=1920 instead of scale_load(MIN_SHARES)=2*1024. In
+	 * case no task is runnable on a CPU MIN_SHARES=2 should be returned
+	 * instead of 0.
+	 */
+	return clamp_t(long, shares, MIN_SHARES, tg_shares);
+}
+#endif /* CONFIG_SMP */
+
+/*
+ * Recomputes the group entity based on the current state of its group
+ * runqueue.
+ */
+static void update_cfs_group(struct sched_entity *se)
+{
+	struct cfs_rq *gcfs_rq = group_cfs_rq(se);
+	long shares;
+
+	if (!gcfs_rq)
+		return;
+
+	if (throttled_hierarchy(gcfs_rq))
+		return;
+
+#ifndef CONFIG_SMP
+	shares = READ_ONCE(gcfs_rq->tg->shares);
+#else
+	shares = calc_group_shares(gcfs_rq);
+#endif
+	if (unlikely(se->load.weight != shares))
+		reweight_entity(cfs_rq_of(se), se, shares);
+}
+
+#else /* CONFIG_FAIR_GROUP_SCHED */
+static inline void update_cfs_group(struct sched_entity *se)
+{
+}
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq, int flags)
+{
+	struct rq *rq = rq_of(cfs_rq);
+
+	if (&rq->cfs == cfs_rq) {
+		/*
+		 * There are a few boundary cases this might miss but it should
+		 * get called often enough that that should (hopefully) not be
+		 * a real problem.
+		 *
+		 * It will not get called when we go idle, because the idle
+		 * thread is a different class (!fair), nor will the utilization
+		 * number include things like RT tasks.
+		 *
+		 * As is, the util number is not freq-invariant (we'd have to
+		 * implement arch_scale_freq_capacity() for that).
+		 *
+		 * See cpu_util_cfs().
+		 */
+		cpufreq_update_util(rq, flags);
+	}
+}
+
+#ifdef CONFIG_SMP
+static inline bool load_avg_is_decayed(struct sched_avg *sa)
+{
+	if (sa->load_sum)
+		return false;
+
+	if (sa->util_sum)
+		return false;
+
+	if (sa->runnable_sum)
+		return false;
+
+	/*
+	 * _avg must be null when _sum are null because _avg = _sum / divider
+	 * Make sure that rounding and/or propagation of PELT values never
+	 * break this.
+	 */
+	SCHED_WARN_ON(sa->load_avg ||
+		      sa->util_avg ||
+		      sa->runnable_avg);
+
+	return true;
+}
+
+static inline u64 cfs_rq_last_update_time(struct cfs_rq *cfs_rq)
+{
+	return u64_u32_load_copy(cfs_rq->avg.last_update_time,
+				 cfs_rq->last_update_time_copy);
+}
+#ifdef CONFIG_FAIR_GROUP_SCHED
+/*
+ * Because list_add_leaf_cfs_rq always places a child cfs_rq on the list
+ * immediately before a parent cfs_rq, and cfs_rqs are removed from the list
+ * bottom-up, we only have to test whether the cfs_rq before us on the list
+ * is our child.
+ * If cfs_rq is not on the list, test whether a child needs its to be added to
+ * connect a branch to the tree  * (see list_add_leaf_cfs_rq() for details).
+ */
+static inline bool child_cfs_rq_on_list(struct cfs_rq *cfs_rq)
+{
+	struct cfs_rq *prev_cfs_rq;
+	struct list_head *prev;
+
+	if (cfs_rq->on_list) {
+		prev = cfs_rq->leaf_cfs_rq_list.prev;
+	} else {
+		struct rq *rq = rq_of(cfs_rq);
+
+		prev = rq->tmp_alone_branch;
+	}
+
+	prev_cfs_rq = container_of(prev, struct cfs_rq, leaf_cfs_rq_list);
+
+	return (prev_cfs_rq->tg->parent == cfs_rq->tg);
+}
+
+static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq)
+{
+	if (cfs_rq->load.weight)
+		return false;
+
+	if (!load_avg_is_decayed(&cfs_rq->avg))
+		return false;
+
+	if (child_cfs_rq_on_list(cfs_rq))
+		return false;
+
+	return true;
+}
+
+/**
+ * update_tg_load_avg - update the tg's load avg
+ * @cfs_rq: the cfs_rq whose avg changed
+ *
+ * This function 'ensures': tg->load_avg := \Sum tg->cfs_rq[]->avg.load.
+ * However, because tg->load_avg is a global value there are performance
+ * considerations.
+ *
+ * In order to avoid having to look at the other cfs_rq's, we use a
+ * differential update where we store the last value we propagated. This in
+ * turn allows skipping updates if the differential is 'small'.
+ *
+ * Updating tg's load_avg is necessary before update_cfs_share().
+ */
+static inline void update_tg_load_avg(struct cfs_rq *cfs_rq)
+{
+	long delta = cfs_rq->avg.load_avg - cfs_rq->tg_load_avg_contrib;
+
+	/*
+	 * No need to update load_avg for root_task_group as it is not used.
+	 */
+	if (cfs_rq->tg == &root_task_group)
+		return;
+
+	if (abs(delta) > cfs_rq->tg_load_avg_contrib / 64) {
+		atomic_long_add(delta, &cfs_rq->tg->load_avg);
+		cfs_rq->tg_load_avg_contrib = cfs_rq->avg.load_avg;
+	}
+}
+
+/*
+ * Called within set_task_rq() right before setting a task's CPU. The
+ * caller only guarantees p->pi_lock is held; no other assumptions,
+ * including the state of rq->lock, should be made.
+ */
+void set_task_rq_fair(struct sched_entity *se,
+		      struct cfs_rq *prev, struct cfs_rq *next)
+{
+	u64 p_last_update_time;
+	u64 n_last_update_time;
+
+	if (!sched_feat(ATTACH_AGE_LOAD))
+		return;
+
+	/*
+	 * We are supposed to update the task to "current" time, then its up to
+	 * date and ready to go to new CPU/cfs_rq. But we have difficulty in
+	 * getting what current time is, so simply throw away the out-of-date
+	 * time. This will result in the wakee task is less decayed, but giving
+	 * the wakee more load sounds not bad.
+	 */
+	if (!(se->avg.last_update_time && prev))
+		return;
+
+	p_last_update_time = cfs_rq_last_update_time(prev);
+	n_last_update_time = cfs_rq_last_update_time(next);
+
+	__update_load_avg_blocked_se(p_last_update_time, se);
+	se->avg.last_update_time = n_last_update_time;
+}
+
+/*
+ * When on migration a sched_entity joins/leaves the PELT hierarchy, we need to
+ * propagate its contribution. The key to this propagation is the invariant
+ * that for each group:
+ *
+ *   ge->avg == grq->avg						(1)
+ *
+ * _IFF_ we look at the pure running and runnable sums. Because they
+ * represent the very same entity, just at different points in the hierarchy.
+ *
+ * Per the above update_tg_cfs_util() and update_tg_cfs_runnable() are trivial
+ * and simply copies the running/runnable sum over (but still wrong, because
+ * the group entity and group rq do not have their PELT windows aligned).
+ *
+ * However, update_tg_cfs_load() is more complex. So we have:
+ *
+ *   ge->avg.load_avg = ge->load.weight * ge->avg.runnable_avg		(2)
+ *
+ * And since, like util, the runnable part should be directly transferable,
+ * the following would _appear_ to be the straight forward approach:
+ *
+ *   grq->avg.load_avg = grq->load.weight * grq->avg.runnable_avg	(3)
+ *
+ * And per (1) we have:
+ *
+ *   ge->avg.runnable_avg == grq->avg.runnable_avg
+ *
+ * Which gives:
+ *
+ *                      ge->load.weight * grq->avg.load_avg
+ *   ge->avg.load_avg = -----------------------------------		(4)
+ *                               grq->load.weight
+ *
+ * Except that is wrong!
+ *
+ * Because while for entities historical weight is not important and we
+ * really only care about our future and therefore can consider a pure
+ * runnable sum, runqueues can NOT do this.
+ *
+ * We specifically want runqueues to have a load_avg that includes
+ * historical weights. Those represent the blocked load, the load we expect
+ * to (shortly) return to us. This only works by keeping the weights as
+ * integral part of the sum. We therefore cannot decompose as per (3).
+ *
+ * Another reason this doesn't work is that runnable isn't a 0-sum entity.
+ * Imagine a rq with 2 tasks that each are runnable 2/3 of the time. Then the
+ * rq itself is runnable anywhere between 2/3 and 1 depending on how the
+ * runnable section of these tasks overlap (or not). If they were to perfectly
+ * align the rq as a whole would be runnable 2/3 of the time. If however we
+ * always have at least 1 runnable task, the rq as a whole is always runnable.
+ *
+ * So we'll have to approximate.. :/
+ *
+ * Given the constraint:
+ *
+ *   ge->avg.running_sum <= ge->avg.runnable_sum <= LOAD_AVG_MAX
+ *
+ * We can construct a rule that adds runnable to a rq by assuming minimal
+ * overlap.
+ *
+ * On removal, we'll assume each task is equally runnable; which yields:
+ *
+ *   grq->avg.runnable_sum = grq->avg.load_sum / grq->load.weight
+ *
+ * XXX: only do this for the part of runnable > running ?
+ *
+ */
+static inline void
+update_tg_cfs_util(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cfs_rq *gcfs_rq)
+{
+	long delta_sum, delta_avg = gcfs_rq->avg.util_avg - se->avg.util_avg;
+	u32 new_sum, divider;
+
+	/* Nothing to update */
+	if (!delta_avg)
+		return;
+
+	/*
+	 * cfs_rq->avg.period_contrib can be used for both cfs_rq and se.
+	 * See ___update_load_avg() for details.
+	 */
+	divider = get_pelt_divider(&cfs_rq->avg);
+
+
+	/* Set new sched_entity's utilization */
+	se->avg.util_avg = gcfs_rq->avg.util_avg;
+	new_sum = se->avg.util_avg * divider;
+	delta_sum = (long)new_sum - (long)se->avg.util_sum;
+	se->avg.util_sum = new_sum;
+
+	/* Update parent cfs_rq utilization */
+	add_positive(&cfs_rq->avg.util_avg, delta_avg);
+	add_positive(&cfs_rq->avg.util_sum, delta_sum);
+
+	/* See update_cfs_rq_load_avg() */
+	cfs_rq->avg.util_sum = max_t(u32, cfs_rq->avg.util_sum,
+					  cfs_rq->avg.util_avg * PELT_MIN_DIVIDER);
+}
+
+static inline void
+update_tg_cfs_runnable(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cfs_rq *gcfs_rq)
+{
+	long delta_sum, delta_avg = gcfs_rq->avg.runnable_avg - se->avg.runnable_avg;
+	u32 new_sum, divider;
+
+	/* Nothing to update */
+	if (!delta_avg)
+		return;
+
+	/*
+	 * cfs_rq->avg.period_contrib can be used for both cfs_rq and se.
+	 * See ___update_load_avg() for details.
+	 */
+	divider = get_pelt_divider(&cfs_rq->avg);
+
+	/* Set new sched_entity's runnable */
+	se->avg.runnable_avg = gcfs_rq->avg.runnable_avg;
+	new_sum = se->avg.runnable_avg * divider;
+	delta_sum = (long)new_sum - (long)se->avg.runnable_sum;
+	se->avg.runnable_sum = new_sum;
+
+	/* Update parent cfs_rq runnable */
+	add_positive(&cfs_rq->avg.runnable_avg, delta_avg);
+	add_positive(&cfs_rq->avg.runnable_sum, delta_sum);
+	/* See update_cfs_rq_load_avg() */
+	cfs_rq->avg.runnable_sum = max_t(u32, cfs_rq->avg.runnable_sum,
+					      cfs_rq->avg.runnable_avg * PELT_MIN_DIVIDER);
+}
+
+static inline void
+update_tg_cfs_load(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cfs_rq *gcfs_rq)
+{
+	long delta_avg, running_sum, runnable_sum = gcfs_rq->prop_runnable_sum;
+	unsigned long load_avg;
+	u64 load_sum = 0;
+	s64 delta_sum;
+	u32 divider;
+
+	if (!runnable_sum)
+		return;
+
+	gcfs_rq->prop_runnable_sum = 0;
+
+	/*
+	 * cfs_rq->avg.period_contrib can be used for both cfs_rq and se.
+	 * See ___update_load_avg() for details.
+	 */
+	divider = get_pelt_divider(&cfs_rq->avg);
+
+	if (runnable_sum >= 0) {
+		/*
+		 * Add runnable; clip at LOAD_AVG_MAX. Reflects that until
+		 * the CPU is saturated running == runnable.
+		 */
+		runnable_sum += se->avg.load_sum;
+		runnable_sum = min_t(long, runnable_sum, divider);
+	} else {
+		/*
+		 * Estimate the new unweighted runnable_sum of the gcfs_rq by
+		 * assuming all tasks are equally runnable.
+		 */
+		if (scale_load_down(gcfs_rq->load.weight)) {
+			load_sum = div_u64(gcfs_rq->avg.load_sum,
+				scale_load_down(gcfs_rq->load.weight));
+		}
+
+		/* But make sure to not inflate se's runnable */
+		runnable_sum = min(se->avg.load_sum, load_sum);
+	}
+
+	/*
+	 * runnable_sum can't be lower than running_sum
+	 * Rescale running sum to be in the same range as runnable sum
+	 * running_sum is in [0 : LOAD_AVG_MAX <<  SCHED_CAPACITY_SHIFT]
+	 * runnable_sum is in [0 : LOAD_AVG_MAX]
+	 */
+	running_sum = se->avg.util_sum >> SCHED_CAPACITY_SHIFT;
+	runnable_sum = max(runnable_sum, running_sum);
+
+	load_sum = se_weight(se) * runnable_sum;
+	load_avg = div_u64(load_sum, divider);
+
+	delta_avg = load_avg - se->avg.load_avg;
+	if (!delta_avg)
+		return;
+
+	delta_sum = load_sum - (s64)se_weight(se) * se->avg.load_sum;
+
+	se->avg.load_sum = runnable_sum;
+	se->avg.load_avg = load_avg;
+	add_positive(&cfs_rq->avg.load_avg, delta_avg);
+	add_positive(&cfs_rq->avg.load_sum, delta_sum);
+	/* See update_cfs_rq_load_avg() */
+	cfs_rq->avg.load_sum = max_t(u32, cfs_rq->avg.load_sum,
+					  cfs_rq->avg.load_avg * PELT_MIN_DIVIDER);
+}
+
+static inline void add_tg_cfs_propagate(struct cfs_rq *cfs_rq, long runnable_sum)
+{
+	cfs_rq->propagate = 1;
+	cfs_rq->prop_runnable_sum += runnable_sum;
+}
+
+/* Update task and its cfs_rq load average */
+static inline int propagate_entity_load_avg(struct sched_entity *se)
+{
+	struct cfs_rq *cfs_rq, *gcfs_rq;
+
+	if (entity_is_task(se))
+		return 0;
+
+	gcfs_rq = group_cfs_rq(se);
+	if (!gcfs_rq->propagate)
+		return 0;
+
+	gcfs_rq->propagate = 0;
+
+	cfs_rq = cfs_rq_of(se);
+
+	add_tg_cfs_propagate(cfs_rq, gcfs_rq->prop_runnable_sum);
+
+	update_tg_cfs_util(cfs_rq, se, gcfs_rq);
+	update_tg_cfs_runnable(cfs_rq, se, gcfs_rq);
+	update_tg_cfs_load(cfs_rq, se, gcfs_rq);
+
+	trace_pelt_cfs_tp(cfs_rq);
+	trace_pelt_se_tp(se);
+
+	return 1;
+}
+
+/*
+ * Check if we need to update the load and the utilization of a blocked
+ * group_entity:
+ */
+static inline bool skip_blocked_update(struct sched_entity *se)
+{
+	struct cfs_rq *gcfs_rq = group_cfs_rq(se);
+
+	/*
+	 * If sched_entity still have not zero load or utilization, we have to
+	 * decay it:
+	 */
+	if (se->avg.load_avg || se->avg.util_avg)
+		return false;
+
+	/*
+	 * If there is a pending propagation, we have to update the load and
+	 * the utilization of the sched_entity:
+	 */
+	if (gcfs_rq->propagate)
+		return false;
+
+	/*
+	 * Otherwise, the load and the utilization of the sched_entity is
+	 * already zero and there is no pending propagation, so it will be a
+	 * waste of time to try to decay it:
+	 */
+	return true;
+}
+
+#else /* CONFIG_FAIR_GROUP_SCHED */
+
+static inline void update_tg_load_avg(struct cfs_rq *cfs_rq) {}
+
+static inline int propagate_entity_load_avg(struct sched_entity *se)
+{
+	return 0;
+}
+
+static inline void add_tg_cfs_propagate(struct cfs_rq *cfs_rq, long runnable_sum) {}
+
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+#ifdef CONFIG_NO_HZ_COMMON
+static inline void migrate_se_pelt_lag(struct sched_entity *se)
+{
+	u64 throttled = 0, now, lut;
+	struct cfs_rq *cfs_rq;
+	struct rq *rq;
+	bool is_idle;
+
+	if (load_avg_is_decayed(&se->avg))
+		return;
+
+	cfs_rq = cfs_rq_of(se);
+	rq = rq_of(cfs_rq);
+
+	rcu_read_lock();
+	is_idle = is_idle_task(rcu_dereference(rq->curr));
+	rcu_read_unlock();
+
+	/*
+	 * The lag estimation comes with a cost we don't want to pay all the
+	 * time. Hence, limiting to the case where the source CPU is idle and
+	 * we know we are at the greatest risk to have an outdated clock.
+	 */
+	if (!is_idle)
+		return;
+
+	/*
+	 * Estimated "now" is: last_update_time + cfs_idle_lag + rq_idle_lag, where:
+	 *
+	 *   last_update_time (the cfs_rq's last_update_time)
+	 *	= cfs_rq_clock_pelt()@cfs_rq_idle
+	 *      = rq_clock_pelt()@cfs_rq_idle
+	 *        - cfs->throttled_clock_pelt_time@cfs_rq_idle
+	 *
+	 *   cfs_idle_lag (delta between rq's update and cfs_rq's update)
+	 *      = rq_clock_pelt()@rq_idle - rq_clock_pelt()@cfs_rq_idle
+	 *
+	 *   rq_idle_lag (delta between now and rq's update)
+	 *      = sched_clock_cpu() - rq_clock()@rq_idle
+	 *
+	 * We can then write:
+	 *
+	 *    now = rq_clock_pelt()@rq_idle - cfs->throttled_clock_pelt_time +
+	 *          sched_clock_cpu() - rq_clock()@rq_idle
+	 * Where:
+	 *      rq_clock_pelt()@rq_idle is rq->clock_pelt_idle
+	 *      rq_clock()@rq_idle      is rq->clock_idle
+	 *      cfs->throttled_clock_pelt_time@cfs_rq_idle
+	 *                              is cfs_rq->throttled_pelt_idle
+	 */
+
+#ifdef CONFIG_CFS_BANDWIDTH
+	throttled = u64_u32_load(cfs_rq->throttled_pelt_idle);
+	/* The clock has been stopped for throttling */
+	if (throttled == U64_MAX)
+		return;
+#endif
+	now = u64_u32_load(rq->clock_pelt_idle);
+	/*
+	 * Paired with _update_idle_rq_clock_pelt(). It ensures at the worst case
+	 * is observed the old clock_pelt_idle value and the new clock_idle,
+	 * which lead to an underestimation. The opposite would lead to an
+	 * overestimation.
+	 */
+	smp_rmb();
+	lut = cfs_rq_last_update_time(cfs_rq);
+
+	now -= throttled;
+	if (now < lut)
+		/*
+		 * cfs_rq->avg.last_update_time is more recent than our
+		 * estimation, let's use it.
+		 */
+		now = lut;
+	else
+		now += sched_clock_cpu(cpu_of(rq)) - u64_u32_load(rq->clock_idle);
+
+	__update_load_avg_blocked_se(now, se);
+}
+#else
+static void migrate_se_pelt_lag(struct sched_entity *se) {}
+#endif
+
+/**
+ * update_cfs_rq_load_avg - update the cfs_rq's load/util averages
+ * @now: current time, as per cfs_rq_clock_pelt()
+ * @cfs_rq: cfs_rq to update
+ *
+ * The cfs_rq avg is the direct sum of all its entities (blocked and runnable)
+ * avg. The immediate corollary is that all (fair) tasks must be attached.
+ *
+ * cfs_rq->avg is used for task_h_load() and update_cfs_share() for example.
+ *
+ * Return: true if the load decayed or we removed load.
+ *
+ * Since both these conditions indicate a changed cfs_rq->avg.load we should
+ * call update_tg_load_avg() when this function returns true.
+ */
+static inline int
+update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
+{
+	unsigned long removed_load = 0, removed_util = 0, removed_runnable = 0;
+	struct sched_avg *sa = &cfs_rq->avg;
+	int decayed = 0;
+
+	if (cfs_rq->removed.nr) {
+		unsigned long r;
+		u32 divider = get_pelt_divider(&cfs_rq->avg);
+
+		raw_spin_lock(&cfs_rq->removed.lock);
+		swap(cfs_rq->removed.util_avg, removed_util);
+		swap(cfs_rq->removed.load_avg, removed_load);
+		swap(cfs_rq->removed.runnable_avg, removed_runnable);
+		cfs_rq->removed.nr = 0;
+		raw_spin_unlock(&cfs_rq->removed.lock);
+
+		r = removed_load;
+		sub_positive(&sa->load_avg, r);
+		sub_positive(&sa->load_sum, r * divider);
+		/* See sa->util_sum below */
+		sa->load_sum = max_t(u32, sa->load_sum, sa->load_avg * PELT_MIN_DIVIDER);
+
+		r = removed_util;
+		sub_positive(&sa->util_avg, r);
+		sub_positive(&sa->util_sum, r * divider);
+		/*
+		 * Because of rounding, se->util_sum might ends up being +1 more than
+		 * cfs->util_sum. Although this is not a problem by itself, detaching
+		 * a lot of tasks with the rounding problem between 2 updates of
+		 * util_avg (~1ms) can make cfs->util_sum becoming null whereas
+		 * cfs_util_avg is not.
+		 * Check that util_sum is still above its lower bound for the new
+		 * util_avg. Given that period_contrib might have moved since the last
+		 * sync, we are only sure that util_sum must be above or equal to
+		 *    util_avg * minimum possible divider
+		 */
+		sa->util_sum = max_t(u32, sa->util_sum, sa->util_avg * PELT_MIN_DIVIDER);
+
+		r = removed_runnable;
+		sub_positive(&sa->runnable_avg, r);
+		sub_positive(&sa->runnable_sum, r * divider);
+		/* See sa->util_sum above */
+		sa->runnable_sum = max_t(u32, sa->runnable_sum,
+					      sa->runnable_avg * PELT_MIN_DIVIDER);
+
+		/*
+		 * removed_runnable is the unweighted version of removed_load so we
+		 * can use it to estimate removed_load_sum.
+		 */
+		add_tg_cfs_propagate(cfs_rq,
+			-(long)(removed_runnable * divider) >> SCHED_CAPACITY_SHIFT);
+
+		decayed = 1;
+	}
+
+	decayed |= __update_load_avg_cfs_rq(now, cfs_rq);
+	u64_u32_store_copy(sa->last_update_time,
+			   cfs_rq->last_update_time_copy,
+			   sa->last_update_time);
+	return decayed;
+}
+
+/**
+ * attach_entity_load_avg - attach this entity to its cfs_rq load avg
+ * @cfs_rq: cfs_rq to attach to
+ * @se: sched_entity to attach
+ *
+ * Must call update_cfs_rq_load_avg() before this, since we rely on
+ * cfs_rq->avg.last_update_time being current.
+ */
+static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	/*
+	 * cfs_rq->avg.period_contrib can be used for both cfs_rq and se.
+	 * See ___update_load_avg() for details.
+	 */
+	u32 divider = get_pelt_divider(&cfs_rq->avg);
+
+	/*
+	 * When we attach the @se to the @cfs_rq, we must align the decay
+	 * window because without that, really weird and wonderful things can
+	 * happen.
+	 *
+	 * XXX illustrate
+	 */
+	se->avg.last_update_time = cfs_rq->avg.last_update_time;
+	se->avg.period_contrib = cfs_rq->avg.period_contrib;
+
+	/*
+	 * Hell(o) Nasty stuff.. we need to recompute _sum based on the new
+	 * period_contrib. This isn't strictly correct, but since we're
+	 * entirely outside of the PELT hierarchy, nobody cares if we truncate
+	 * _sum a little.
+	 */
+	se->avg.util_sum = se->avg.util_avg * divider;
+
+	se->avg.runnable_sum = se->avg.runnable_avg * divider;
+
+	se->avg.load_sum = se->avg.load_avg * divider;
+	if (se_weight(se) < se->avg.load_sum)
+		se->avg.load_sum = div_u64(se->avg.load_sum, se_weight(se));
+	else
+		se->avg.load_sum = 1;
+
+	enqueue_load_avg(cfs_rq, se);
+	cfs_rq->avg.util_avg += se->avg.util_avg;
+	cfs_rq->avg.util_sum += se->avg.util_sum;
+	cfs_rq->avg.runnable_avg += se->avg.runnable_avg;
+	cfs_rq->avg.runnable_sum += se->avg.runnable_sum;
+
+	add_tg_cfs_propagate(cfs_rq, se->avg.load_sum);
+
+	cfs_rq_util_change(cfs_rq, 0);
+
+	trace_pelt_cfs_tp(cfs_rq);
+}
+
+/**
+ * detach_entity_load_avg - detach this entity from its cfs_rq load avg
+ * @cfs_rq: cfs_rq to detach from
+ * @se: sched_entity to detach
+ *
+ * Must call update_cfs_rq_load_avg() before this, since we rely on
+ * cfs_rq->avg.last_update_time being current.
+ */
+static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	dequeue_load_avg(cfs_rq, se);
+	sub_positive(&cfs_rq->avg.util_avg, se->avg.util_avg);
+	sub_positive(&cfs_rq->avg.util_sum, se->avg.util_sum);
+	/* See update_cfs_rq_load_avg() */
+	cfs_rq->avg.util_sum = max_t(u32, cfs_rq->avg.util_sum,
+					  cfs_rq->avg.util_avg * PELT_MIN_DIVIDER);
+
+	sub_positive(&cfs_rq->avg.runnable_avg, se->avg.runnable_avg);
+	sub_positive(&cfs_rq->avg.runnable_sum, se->avg.runnable_sum);
+	/* See update_cfs_rq_load_avg() */
+	cfs_rq->avg.runnable_sum = max_t(u32, cfs_rq->avg.runnable_sum,
+					      cfs_rq->avg.runnable_avg * PELT_MIN_DIVIDER);
+
+	add_tg_cfs_propagate(cfs_rq, -se->avg.load_sum);
+
+	cfs_rq_util_change(cfs_rq, 0);
+
+	trace_pelt_cfs_tp(cfs_rq);
+}
+
+/*
+ * Optional action to be done while updating the load average
+ */
+#define UPDATE_TG	0x1
+#define SKIP_AGE_LOAD	0x2
+#define DO_ATTACH	0x4
+#define DO_DETACH	0x8
+
+/* Update task and its cfs_rq load average */
+static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
+{
+	u64 now = cfs_rq_clock_pelt(cfs_rq);
+	int decayed;
+
+	/*
+	 * Track task load average for carrying it to new CPU after migrated, and
+	 * track group sched_entity load average for task_h_load calc in migration
+	 */
+	if (se->avg.last_update_time && !(flags & SKIP_AGE_LOAD))
+		__update_load_avg_se(now, cfs_rq, se);
+
+	decayed  = update_cfs_rq_load_avg(now, cfs_rq);
+	decayed |= propagate_entity_load_avg(se);
+
+	if (!se->avg.last_update_time && (flags & DO_ATTACH)) {
+
+		/*
+		 * DO_ATTACH means we're here from enqueue_entity().
+		 * !last_update_time means we've passed through
+		 * migrate_task_rq_fair() indicating we migrated.
+		 *
+		 * IOW we're enqueueing a task on a new CPU.
+		 */
+		attach_entity_load_avg(cfs_rq, se);
+		update_tg_load_avg(cfs_rq);
+
+	} else if (flags & DO_DETACH) {
+		/*
+		 * DO_DETACH means we're here from dequeue_entity()
+		 * and we are migrating task out of the CPU.
+		 */
+		detach_entity_load_avg(cfs_rq, se);
+		update_tg_load_avg(cfs_rq);
+	} else if (decayed) {
+		cfs_rq_util_change(cfs_rq, 0);
+
+		if (flags & UPDATE_TG)
+			update_tg_load_avg(cfs_rq);
+	}
+}
+
+/*
+ * Synchronize entity load avg of dequeued entity without locking
+ * the previous rq.
+ */
+static void sync_entity_load_avg(struct sched_entity *se)
+{
+	struct cfs_rq *cfs_rq = cfs_rq_of(se);
+	u64 last_update_time;
+
+	last_update_time = cfs_rq_last_update_time(cfs_rq);
+	__update_load_avg_blocked_se(last_update_time, se);
+}
+
+/*
+ * Task first catches up with cfs_rq, and then subtract
+ * itself from the cfs_rq (task must be off the queue now).
+ */
+static void remove_entity_load_avg(struct sched_entity *se)
+{
+	struct cfs_rq *cfs_rq = cfs_rq_of(se);
+	unsigned long flags;
+
+	/*
+	 * tasks cannot exit without having gone through wake_up_new_task() ->
+	 * enqueue_task_fair() which will have added things to the cfs_rq,
+	 * so we can remove unconditionally.
+	 */
+
+	sync_entity_load_avg(se);
+
+	raw_spin_lock_irqsave(&cfs_rq->removed.lock, flags);
+	++cfs_rq->removed.nr;
+	cfs_rq->removed.util_avg	+= se->avg.util_avg;
+	cfs_rq->removed.load_avg	+= se->avg.load_avg;
+	cfs_rq->removed.runnable_avg	+= se->avg.runnable_avg;
+	raw_spin_unlock_irqrestore(&cfs_rq->removed.lock, flags);
+}
+
+static inline unsigned long cfs_rq_runnable_avg(struct cfs_rq *cfs_rq)
+{
+	return cfs_rq->avg.runnable_avg;
+}
+
+static inline unsigned long cfs_rq_load_avg(struct cfs_rq *cfs_rq)
+{
+	return cfs_rq->avg.load_avg;
+}
+
+static int newidle_balance(struct rq *this_rq, struct rq_flags *rf);
+
+static inline unsigned long task_util(struct task_struct *p)
+{
+	return READ_ONCE(p->se.avg.util_avg);
+}
+
+static inline unsigned long _task_util_est(struct task_struct *p)
+{
+	struct util_est ue = READ_ONCE(p->se.avg.util_est);
+
+	return max(ue.ewma, (ue.enqueued & ~UTIL_AVG_UNCHANGED));
+}
+
+static inline unsigned long task_util_est(struct task_struct *p)
+{
+	return max(task_util(p), _task_util_est(p));
+}
+
+static inline void util_est_enqueue(struct cfs_rq *cfs_rq,
+				    struct task_struct *p)
+{
+	unsigned int enqueued;
+
+	if (!sched_feat(UTIL_EST))
+		return;
+
+	/* Update root cfs_rq's estimated utilization */
+	enqueued  = cfs_rq->avg.util_est.enqueued;
+	enqueued += _task_util_est(p);
+	WRITE_ONCE(cfs_rq->avg.util_est.enqueued, enqueued);
+
+	trace_sched_util_est_cfs_tp(cfs_rq);
+}
+
+static inline void util_est_dequeue(struct cfs_rq *cfs_rq,
+				    struct task_struct *p)
+{
+	unsigned int enqueued;
+
+	if (!sched_feat(UTIL_EST))
+		return;
+
+	/* Update root cfs_rq's estimated utilization */
+	enqueued  = cfs_rq->avg.util_est.enqueued;
+	enqueued -= min_t(unsigned int, enqueued, _task_util_est(p));
+	WRITE_ONCE(cfs_rq->avg.util_est.enqueued, enqueued);
+
+	trace_sched_util_est_cfs_tp(cfs_rq);
+}
+
+#define UTIL_EST_MARGIN (SCHED_CAPACITY_SCALE / 100)
+
+/*
+ * Check if a (signed) value is within a specified (unsigned) margin,
+ * based on the observation that:
+ *
+ *     abs(x) < y := (unsigned)(x + y - 1) < (2 * y - 1)
+ *
+ * NOTE: this only works when value + margin < INT_MAX.
+ */
+static inline bool within_margin(int value, int margin)
+{
+	return ((unsigned int)(value + margin - 1) < (2 * margin - 1));
+}
+
+static inline void util_est_update(struct cfs_rq *cfs_rq,
+				   struct task_struct *p,
+				   bool task_sleep)
+{
+	long last_ewma_diff, last_enqueued_diff;
+	struct util_est ue;
+
+	if (!sched_feat(UTIL_EST))
+		return;
+
+	/*
+	 * Skip update of task's estimated utilization when the task has not
+	 * yet completed an activation, e.g. being migrated.
+	 */
+	if (!task_sleep)
+		return;
+
+	/*
+	 * If the PELT values haven't changed since enqueue time,
+	 * skip the util_est update.
+	 */
+	ue = p->se.avg.util_est;
+	if (ue.enqueued & UTIL_AVG_UNCHANGED)
+		return;
+
+	last_enqueued_diff = ue.enqueued;
+
+	/*
+	 * Reset EWMA on utilization increases, the moving average is used only
+	 * to smooth utilization decreases.
+	 */
+	ue.enqueued = task_util(p);
+	if (sched_feat(UTIL_EST_FASTUP)) {
+		if (ue.ewma < ue.enqueued) {
+			ue.ewma = ue.enqueued;
+			goto done;
+		}
+	}
+
+	/*
+	 * Skip update of task's estimated utilization when its members are
+	 * already ~1% close to its last activation value.
+	 */
+	last_ewma_diff = ue.enqueued - ue.ewma;
+	last_enqueued_diff -= ue.enqueued;
+	if (within_margin(last_ewma_diff, UTIL_EST_MARGIN)) {
+		if (!within_margin(last_enqueued_diff, UTIL_EST_MARGIN))
+			goto done;
+
+		return;
+	}
+
+	/*
+	 * To avoid overestimation of actual task utilization, skip updates if
+	 * we cannot grant there is idle time in this CPU.
+	 */
+	if (task_util(p) > capacity_orig_of(cpu_of(rq_of(cfs_rq))))
+		return;
+
+	/*
+	 * Update Task's estimated utilization
+	 *
+	 * When *p completes an activation we can consolidate another sample
+	 * of the task size. This is done by storing the current PELT value
+	 * as ue.enqueued and by using this value to update the Exponential
+	 * Weighted Moving Average (EWMA):
+	 *
+	 *  ewma(t) = w *  task_util(p) + (1-w) * ewma(t-1)
+	 *          = w *  task_util(p) +         ewma(t-1)  - w * ewma(t-1)
+	 *          = w * (task_util(p) -         ewma(t-1)) +     ewma(t-1)
+	 *          = w * (      last_ewma_diff            ) +     ewma(t-1)
+	 *          = w * (last_ewma_diff  +  ewma(t-1) / w)
+	 *
+	 * Where 'w' is the weight of new samples, which is configured to be
+	 * 0.25, thus making w=1/4 ( >>= UTIL_EST_WEIGHT_SHIFT)
+	 */
+	ue.ewma <<= UTIL_EST_WEIGHT_SHIFT;
+	ue.ewma  += last_ewma_diff;
+	ue.ewma >>= UTIL_EST_WEIGHT_SHIFT;
+done:
+	ue.enqueued |= UTIL_AVG_UNCHANGED;
+	WRITE_ONCE(p->se.avg.util_est, ue);
+
+	trace_sched_util_est_se_tp(&p->se);
+}
+
+static inline int util_fits_cpu(unsigned long util,
+				unsigned long uclamp_min,
+				unsigned long uclamp_max,
+				int cpu)
+{
+	unsigned long capacity_orig, capacity_orig_thermal;
+	unsigned long capacity = capacity_of(cpu);
+	bool fits, uclamp_max_fits;
+
+	/*
+	 * Check if the real util fits without any uclamp boost/cap applied.
+	 */
+	fits = fits_capacity(util, capacity);
+
+	if (!uclamp_is_used())
+		return fits;
+
+	/*
+	 * We must use capacity_orig_of() for comparing against uclamp_min and
+	 * uclamp_max. We only care about capacity pressure (by using
+	 * capacity_of()) for comparing against the real util.
+	 *
+	 * If a task is boosted to 1024 for example, we don't want a tiny
+	 * pressure to skew the check whether it fits a CPU or not.
+	 *
+	 * Similarly if a task is capped to capacity_orig_of(little_cpu), it
+	 * should fit a little cpu even if there's some pressure.
+	 *
+	 * Only exception is for thermal pressure since it has a direct impact
+	 * on available OPP of the system.
+	 *
+	 * We honour it for uclamp_min only as a drop in performance level
+	 * could result in not getting the requested minimum performance level.
+	 *
+	 * For uclamp_max, we can tolerate a drop in performance level as the
+	 * goal is to cap the task. So it's okay if it's getting less.
+	 */
+	capacity_orig = capacity_orig_of(cpu);
+	capacity_orig_thermal = capacity_orig - arch_scale_thermal_pressure(cpu);
+
+	/*
+	 * We want to force a task to fit a cpu as implied by uclamp_max.
+	 * But we do have some corner cases to cater for..
+	 *
+	 *
+	 *                                 C=z
+	 *   |                             ___
+	 *   |                  C=y       |   |
+	 *   |_ _ _ _ _ _ _ _ _ ___ _ _ _ | _ | _ _ _ _ _  uclamp_max
+	 *   |      C=x        |   |      |   |
+	 *   |      ___        |   |      |   |
+	 *   |     |   |       |   |      |   |    (util somewhere in this region)
+	 *   |     |   |       |   |      |   |
+	 *   |     |   |       |   |      |   |
+	 *   +----------------------------------------
+	 *         cpu0        cpu1       cpu2
+	 *
+	 *   In the above example if a task is capped to a specific performance
+	 *   point, y, then when:
+	 *
+	 *   * util = 80% of x then it does not fit on cpu0 and should migrate
+	 *     to cpu1
+	 *   * util = 80% of y then it is forced to fit on cpu1 to honour
+	 *     uclamp_max request.
+	 *
+	 *   which is what we're enforcing here. A task always fits if
+	 *   uclamp_max <= capacity_orig. But when uclamp_max > capacity_orig,
+	 *   the normal upmigration rules should withhold still.
+	 *
+	 *   Only exception is when we are on max capacity, then we need to be
+	 *   careful not to block overutilized state. This is so because:
+	 *
+	 *     1. There's no concept of capping at max_capacity! We can't go
+	 *        beyond this performance level anyway.
+	 *     2. The system is being saturated when we're operating near
+	 *        max capacity, it doesn't make sense to block overutilized.
+	 */
+	uclamp_max_fits = (capacity_orig == SCHED_CAPACITY_SCALE) && (uclamp_max == SCHED_CAPACITY_SCALE);
+	uclamp_max_fits = !uclamp_max_fits && (uclamp_max <= capacity_orig);
+	fits = fits || uclamp_max_fits;
+
+	/*
+	 *
+	 *                                 C=z
+	 *   |                             ___       (region a, capped, util >= uclamp_max)
+	 *   |                  C=y       |   |
+	 *   |_ _ _ _ _ _ _ _ _ ___ _ _ _ | _ | _ _ _ _ _ uclamp_max
+	 *   |      C=x        |   |      |   |
+	 *   |      ___        |   |      |   |      (region b, uclamp_min <= util <= uclamp_max)
+	 *   |_ _ _|_ _|_ _ _ _| _ | _ _ _| _ | _ _ _ _ _ uclamp_min
+	 *   |     |   |       |   |      |   |
+	 *   |     |   |       |   |      |   |      (region c, boosted, util < uclamp_min)
+	 *   +----------------------------------------
+	 *         cpu0        cpu1       cpu2
+	 *
+	 * a) If util > uclamp_max, then we're capped, we don't care about
+	 *    actual fitness value here. We only care if uclamp_max fits
+	 *    capacity without taking margin/pressure into account.
+	 *    See comment above.
+	 *
+	 * b) If uclamp_min <= util <= uclamp_max, then the normal
+	 *    fits_capacity() rules apply. Except we need to ensure that we
+	 *    enforce we remain within uclamp_max, see comment above.
+	 *
+	 * c) If util < uclamp_min, then we are boosted. Same as (b) but we
+	 *    need to take into account the boosted value fits the CPU without
+	 *    taking margin/pressure into account.
+	 *
+	 * Cases (a) and (b) are handled in the 'fits' variable already. We
+	 * just need to consider an extra check for case (c) after ensuring we
+	 * handle the case uclamp_min > uclamp_max.
+	 */
+	uclamp_min = min(uclamp_min, uclamp_max);
+	if (fits && (util < uclamp_min) && (uclamp_min > capacity_orig_thermal))
+		return -1;
+
+	return fits;
+}
+
+static inline int task_fits_cpu(struct task_struct *p, int cpu)
+{
+	unsigned long uclamp_min = uclamp_eff_value(p, UCLAMP_MIN);
+	unsigned long uclamp_max = uclamp_eff_value(p, UCLAMP_MAX);
+	unsigned long util = task_util_est(p);
+	/*
+	 * Return true only if the cpu fully fits the task requirements, which
+	 * include the utilization but also the performance hints.
+	 */
+	return (util_fits_cpu(util, uclamp_min, uclamp_max, cpu) > 0);
+}
+
+static inline void update_misfit_status(struct task_struct *p, struct rq *rq)
+{
+	if (!sched_asym_cpucap_active())
+		return;
+
+	if (!p || p->nr_cpus_allowed == 1) {
+		rq->misfit_task_load = 0;
+		return;
+	}
+
+	if (task_fits_cpu(p, cpu_of(rq))) {
+		rq->misfit_task_load = 0;
+		return;
+	}
+
+	/*
+	 * Make sure that misfit_task_load will not be null even if
+	 * task_h_load() returns 0.
+	 */
+	rq->misfit_task_load = max_t(unsigned long, task_h_load(p), 1);
+}
+
+#else /* CONFIG_SMP */
+
+static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq)
+{
+	return !cfs_rq->nr_running;
+}
+
+#define UPDATE_TG	0x0
+#define SKIP_AGE_LOAD	0x0
+#define DO_ATTACH	0x0
+#define DO_DETACH	0x0
+
+static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int not_used1)
+{
+	cfs_rq_util_change(cfs_rq, 0);
+}
+
+static inline void remove_entity_load_avg(struct sched_entity *se) {}
+
+static inline void
+attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {}
+static inline void
+detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {}
+
+static inline int newidle_balance(struct rq *rq, struct rq_flags *rf)
+{
+	return 0;
+}
+
+static inline void
+util_est_enqueue(struct cfs_rq *cfs_rq, struct task_struct *p) {}
+
+static inline void
+util_est_dequeue(struct cfs_rq *cfs_rq, struct task_struct *p) {}
+
+static inline void
+util_est_update(struct cfs_rq *cfs_rq, struct task_struct *p,
+		bool task_sleep) {}
+static inline void update_misfit_status(struct task_struct *p, struct rq *rq) {}
+
+#endif /* CONFIG_SMP */
+
+static void
+place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
+{
+	u64 vslice, vruntime = avg_vruntime(cfs_rq);
+	s64 lag = 0;
+
+	se->slice = sysctl_sched_base_slice;
+	vslice = calc_delta_fair(se->slice, se);
+
+	/*
+	 * Due to how V is constructed as the weighted average of entities,
+	 * adding tasks with positive lag, or removing tasks with negative lag
+	 * will move 'time' backwards, this can screw around with the lag of
+	 * other tasks.
+	 *
+	 * EEVDF: placement strategy #1 / #2
+	 */
+	if (sched_feat(PLACE_LAG) && cfs_rq->nr_running) {
+		struct sched_entity *curr = cfs_rq->curr;
+		unsigned long load;
+
+		lag = se->vlag;
+
+		/*
+		 * If we want to place a task and preserve lag, we have to
+		 * consider the effect of the new entity on the weighted
+		 * average and compensate for this, otherwise lag can quickly
+		 * evaporate.
+		 *
+		 * Lag is defined as:
+		 *
+		 *   lag_i = S - s_i = w_i * (V - v_i)
+		 *
+		 * To avoid the 'w_i' term all over the place, we only track
+		 * the virtual lag:
+		 *
+		 *   vl_i = V - v_i <=> v_i = V - vl_i
+		 *
+		 * And we take V to be the weighted average of all v:
+		 *
+		 *   V = (\Sum w_j*v_j) / W
+		 *
+		 * Where W is: \Sum w_j
+		 *
+		 * Then, the weighted average after adding an entity with lag
+		 * vl_i is given by:
+		 *
+		 *   V' = (\Sum w_j*v_j + w_i*v_i) / (W + w_i)
+		 *      = (W*V + w_i*(V - vl_i)) / (W + w_i)
+		 *      = (W*V + w_i*V - w_i*vl_i) / (W + w_i)
+		 *      = (V*(W + w_i) - w_i*l) / (W + w_i)
+		 *      = V - w_i*vl_i / (W + w_i)
+		 *
+		 * And the actual lag after adding an entity with vl_i is:
+		 *
+		 *   vl'_i = V' - v_i
+		 *         = V - w_i*vl_i / (W + w_i) - (V - vl_i)
+		 *         = vl_i - w_i*vl_i / (W + w_i)
+		 *
+		 * Which is strictly less than vl_i. So in order to preserve lag
+		 * we should inflate the lag before placement such that the
+		 * effective lag after placement comes out right.
+		 *
+		 * As such, invert the above relation for vl'_i to get the vl_i
+		 * we need to use such that the lag after placement is the lag
+		 * we computed before dequeue.
+		 *
+		 *   vl'_i = vl_i - w_i*vl_i / (W + w_i)
+		 *         = ((W + w_i)*vl_i - w_i*vl_i) / (W + w_i)
+		 *
+		 *   (W + w_i)*vl'_i = (W + w_i)*vl_i - w_i*vl_i
+		 *                   = W*vl_i
+		 *
+		 *   vl_i = (W + w_i)*vl'_i / W
+		 */
+		load = cfs_rq->avg_load;
+		if (curr && curr->on_rq)
+			load += scale_load_down(curr->load.weight);
+
+		lag *= load + scale_load_down(se->load.weight);
+		if (WARN_ON_ONCE(!load))
+			load = 1;
+		lag = div_s64(lag, load);
+	}
+
+	se->vruntime = vruntime - lag;
+
+	/*
+	 * When joining the competition; the exisiting tasks will be,
+	 * on average, halfway through their slice, as such start tasks
+	 * off with half a slice to ease into the competition.
+	 */
+	if (sched_feat(PLACE_DEADLINE_INITIAL) && (flags & ENQUEUE_INITIAL))
+		vslice /= 2;
+
+	/*
+	 * EEVDF: vd_i = ve_i + r_i/w_i
+	 */
+	se->deadline = se->vruntime + vslice;
+}
+
+static void check_enqueue_throttle(struct cfs_rq *cfs_rq);
+static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq);
+
+static inline bool cfs_bandwidth_used(void);
+
+static void
+enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
+{
+	bool curr = cfs_rq->curr == se;
+
+	/*
+	 * If we're the current task, we must renormalise before calling
+	 * update_curr().
+	 */
+	if (curr)
+		place_entity(cfs_rq, se, flags);
+
+	update_curr(cfs_rq);
+
+	/*
+	 * When enqueuing a sched_entity, we must:
+	 *   - Update loads to have both entity and cfs_rq synced with now.
+	 *   - For group_entity, update its runnable_weight to reflect the new
+	 *     h_nr_running of its group cfs_rq.
+	 *   - For group_entity, update its weight to reflect the new share of
+	 *     its group cfs_rq
+	 *   - Add its new weight to cfs_rq->load.weight
+	 */
+	update_load_avg(cfs_rq, se, UPDATE_TG | DO_ATTACH);
+	se_update_runnable(se);
+	/*
+	 * XXX update_load_avg() above will have attached us to the pelt sum;
+	 * but update_cfs_group() here will re-adjust the weight and have to
+	 * undo/redo all that. Seems wasteful.
+	 */
+	update_cfs_group(se);
+
+	/*
+	 * XXX now that the entity has been re-weighted, and it's lag adjusted,
+	 * we can place the entity.
+	 */
+	if (!curr)
+		place_entity(cfs_rq, se, flags);
+
+	account_entity_enqueue(cfs_rq, se);
+
+	/* Entity has migrated, no longer consider this task hot */
+	if (flags & ENQUEUE_MIGRATED)
+		se->exec_start = 0;
+
+	check_schedstat_required();
+	update_stats_enqueue_fair(cfs_rq, se, flags);
+	if (!curr)
+		__enqueue_entity(cfs_rq, se);
+	se->on_rq = 1;
+
+	if (cfs_rq->nr_running == 1) {
+		check_enqueue_throttle(cfs_rq);
+		if (!throttled_hierarchy(cfs_rq)) {
+			list_add_leaf_cfs_rq(cfs_rq);
+		} else {
+#ifdef CONFIG_CFS_BANDWIDTH
+			struct rq *rq = rq_of(cfs_rq);
+
+			if (cfs_rq_throttled(cfs_rq) && !cfs_rq->throttled_clock)
+				cfs_rq->throttled_clock = rq_clock(rq);
+			if (!cfs_rq->throttled_clock_self)
+				cfs_rq->throttled_clock_self = rq_clock(rq);
+#endif
+		}
+	}
+}
+
+static void __clear_buddies_next(struct sched_entity *se)
+{
+	for_each_sched_entity(se) {
+		struct cfs_rq *cfs_rq = cfs_rq_of(se);
+		if (cfs_rq->next != se)
+			break;
+
+		cfs_rq->next = NULL;
+	}
+}
+
+static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	if (cfs_rq->next == se)
+		__clear_buddies_next(se);
+}
+
+static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq);
+
+static void
+dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
+{
+	int action = UPDATE_TG;
+
+	if (entity_is_task(se) && task_on_rq_migrating(task_of(se)))
+		action |= DO_DETACH;
+
+	/*
+	 * Update run-time statistics of the 'current'.
+	 */
+	update_curr(cfs_rq);
+
+	/*
+	 * When dequeuing a sched_entity, we must:
+	 *   - Update loads to have both entity and cfs_rq synced with now.
+	 *   - For group_entity, update its runnable_weight to reflect the new
+	 *     h_nr_running of its group cfs_rq.
+	 *   - Subtract its previous weight from cfs_rq->load.weight.
+	 *   - For group entity, update its weight to reflect the new share
+	 *     of its group cfs_rq.
+	 */
+	update_load_avg(cfs_rq, se, action);
+	se_update_runnable(se);
+
+	update_stats_dequeue_fair(cfs_rq, se, flags);
+
+	clear_buddies(cfs_rq, se);
+
+	update_entity_lag(cfs_rq, se);
+	if (se != cfs_rq->curr)
+		__dequeue_entity(cfs_rq, se);
+	se->on_rq = 0;
+	account_entity_dequeue(cfs_rq, se);
+
+	/* return excess runtime on last dequeue */
+	return_cfs_rq_runtime(cfs_rq);
+
+	update_cfs_group(se);
+
+	/*
+	 * Now advance min_vruntime if @se was the entity holding it back,
+	 * except when: DEQUEUE_SAVE && !DEQUEUE_MOVE, in this case we'll be
+	 * put back on, and if we advance min_vruntime, we'll be placed back
+	 * further than we started -- ie. we'll be penalized.
+	 */
+	if ((flags & (DEQUEUE_SAVE | DEQUEUE_MOVE)) != DEQUEUE_SAVE)
+		update_min_vruntime(cfs_rq);
+
+	if (cfs_rq->nr_running == 0)
+		update_idle_cfs_rq_clock_pelt(cfs_rq);
+}
+
+static void
+set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	clear_buddies(cfs_rq, se);
+
+	/* 'current' is not kept within the tree. */
+	if (se->on_rq) {
+		/*
+		 * Any task has to be enqueued before it get to execute on
+		 * a CPU. So account for the time it spent waiting on the
+		 * runqueue.
+		 */
+		update_stats_wait_end_fair(cfs_rq, se);
+		__dequeue_entity(cfs_rq, se);
+		update_load_avg(cfs_rq, se, UPDATE_TG);
+		/*
+		 * HACK, stash a copy of deadline at the point of pick in vlag,
+		 * which isn't used until dequeue.
+		 */
+		se->vlag = se->deadline;
+	}
+
+	update_stats_curr_start(cfs_rq, se);
+	cfs_rq->curr = se;
+
+	/*
+	 * Track our maximum slice length, if the CPU's load is at
+	 * least twice that of our own weight (i.e. dont track it
+	 * when there are only lesser-weight tasks around):
+	 */
+	if (schedstat_enabled() &&
+	    rq_of(cfs_rq)->cfs.load.weight >= 2*se->load.weight) {
+		struct sched_statistics *stats;
+
+		stats = __schedstats_from_se(se);
+		__schedstat_set(stats->slice_max,
+				max((u64)stats->slice_max,
+				    se->sum_exec_runtime - se->prev_sum_exec_runtime));
+	}
+
+	se->prev_sum_exec_runtime = se->sum_exec_runtime;
+}
+
+/*
+ * Pick the next process, keeping these things in mind, in this order:
+ * 1) keep things fair between processes/task groups
+ * 2) pick the "next" process, since someone really wants that to run
+ * 3) pick the "last" process, for cache locality
+ * 4) do not run the "skip" process, if something else is available
+ */
+static struct sched_entity *
+pick_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *curr)
+{
+	/*
+	 * Enabling NEXT_BUDDY will affect latency but not fairness.
+	 */
+	if (sched_feat(NEXT_BUDDY) &&
+	    cfs_rq->next && entity_eligible(cfs_rq, cfs_rq->next))
+		return cfs_rq->next;
+
+	return pick_eevdf(cfs_rq);
+}
+
+static bool check_cfs_rq_runtime(struct cfs_rq *cfs_rq);
+
+static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev)
+{
+	/*
+	 * If still on the runqueue then deactivate_task()
+	 * was not called and update_curr() has to be done:
+	 */
+	if (prev->on_rq)
+		update_curr(cfs_rq);
+
+	/* throttle cfs_rqs exceeding runtime */
+	check_cfs_rq_runtime(cfs_rq);
+
+	if (prev->on_rq) {
+		update_stats_wait_start_fair(cfs_rq, prev);
+		/* Put 'current' back into the tree. */
+		__enqueue_entity(cfs_rq, prev);
+		/* in !on_rq case, update occurred at dequeue */
+		update_load_avg(cfs_rq, prev, 0);
+	}
+	cfs_rq->curr = NULL;
+}
+
+static void
+entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued)
+{
+	/*
+	 * Update run-time statistics of the 'current'.
+	 */
+	update_curr(cfs_rq);
+
+	/*
+	 * Ensure that runnable average is periodically updated.
+	 */
+	update_load_avg(cfs_rq, curr, UPDATE_TG);
+	update_cfs_group(curr);
+
+#ifdef CONFIG_SCHED_HRTICK
+	/*
+	 * queued ticks are scheduled to match the slice, so don't bother
+	 * validating it and just reschedule.
+	 */
+	if (queued) {
+		resched_curr(rq_of(cfs_rq));
+		return;
+	}
+	/*
+	 * don't let the period tick interfere with the hrtick preemption
+	 */
+	if (!sched_feat(DOUBLE_TICK) &&
+			hrtimer_active(&rq_of(cfs_rq)->hrtick_timer))
+		return;
+#endif
+}
+
+
+/**************************************************
+ * CFS bandwidth control machinery
+ */
+
+#ifdef CONFIG_CFS_BANDWIDTH
+
+#ifdef CONFIG_JUMP_LABEL
+static struct static_key __cfs_bandwidth_used;
+
+static inline bool cfs_bandwidth_used(void)
+{
+	return static_key_false(&__cfs_bandwidth_used);
+}
+
+void cfs_bandwidth_usage_inc(void)
+{
+	static_key_slow_inc_cpuslocked(&__cfs_bandwidth_used);
+}
+
+void cfs_bandwidth_usage_dec(void)
+{
+	static_key_slow_dec_cpuslocked(&__cfs_bandwidth_used);
+}
+#else /* CONFIG_JUMP_LABEL */
+static bool cfs_bandwidth_used(void)
+{
+	return true;
+}
+
+void cfs_bandwidth_usage_inc(void) {}
+void cfs_bandwidth_usage_dec(void) {}
+#endif /* CONFIG_JUMP_LABEL */
+
+/*
+ * default period for cfs group bandwidth.
+ * default: 0.1s, units: nanoseconds
+ */
+static inline u64 default_cfs_period(void)
+{
+	return 100000000ULL;
+}
+
+static inline u64 sched_cfs_bandwidth_slice(void)
+{
+	return (u64)sysctl_sched_cfs_bandwidth_slice * NSEC_PER_USEC;
+}
+
+/*
+ * Replenish runtime according to assigned quota. We use sched_clock_cpu
+ * directly instead of rq->clock to avoid adding additional synchronization
+ * around rq->lock.
+ *
+ * requires cfs_b->lock
+ */
+void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b)
+{
+	s64 runtime;
+
+	if (unlikely(cfs_b->quota == RUNTIME_INF))
+		return;
+
+	cfs_b->runtime += cfs_b->quota;
+	runtime = cfs_b->runtime_snap - cfs_b->runtime;
+	if (runtime > 0) {
+		cfs_b->burst_time += runtime;
+		cfs_b->nr_burst++;
+	}
+
+	cfs_b->runtime = min(cfs_b->runtime, cfs_b->quota + cfs_b->burst);
+	cfs_b->runtime_snap = cfs_b->runtime;
+}
+
+static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg)
+{
+	return &tg->cfs_bandwidth;
+}
+
+/* returns 0 on failure to allocate runtime */
+static int __assign_cfs_rq_runtime(struct cfs_bandwidth *cfs_b,
+				   struct cfs_rq *cfs_rq, u64 target_runtime)
+{
+	u64 min_amount, amount = 0;
+
+	lockdep_assert_held(&cfs_b->lock);
+
+	/* note: this is a positive sum as runtime_remaining <= 0 */
+	min_amount = target_runtime - cfs_rq->runtime_remaining;
+
+	if (cfs_b->quota == RUNTIME_INF)
+		amount = min_amount;
+	else {
+		start_cfs_bandwidth(cfs_b);
+
+		if (cfs_b->runtime > 0) {
+			amount = min(cfs_b->runtime, min_amount);
+			cfs_b->runtime -= amount;
+			cfs_b->idle = 0;
+		}
+	}
+
+	cfs_rq->runtime_remaining += amount;
+
+	return cfs_rq->runtime_remaining > 0;
+}
+
+/* returns 0 on failure to allocate runtime */
+static int assign_cfs_rq_runtime(struct cfs_rq *cfs_rq)
+{
+	struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
+	int ret;
+
+	raw_spin_lock(&cfs_b->lock);
+	ret = __assign_cfs_rq_runtime(cfs_b, cfs_rq, sched_cfs_bandwidth_slice());
+	raw_spin_unlock(&cfs_b->lock);
+
+	return ret;
+}
+
+static void __account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec)
+{
+	/* dock delta_exec before expiring quota (as it could span periods) */
+	cfs_rq->runtime_remaining -= delta_exec;
+
+	if (likely(cfs_rq->runtime_remaining > 0))
+		return;
+
+	if (cfs_rq->throttled)
+		return;
+	/*
+	 * if we're unable to extend our runtime we resched so that the active
+	 * hierarchy can be throttled
+	 */
+	if (!assign_cfs_rq_runtime(cfs_rq) && likely(cfs_rq->curr))
+		resched_curr(rq_of(cfs_rq));
+}
+
+static __always_inline
+void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec)
+{
+	if (!cfs_bandwidth_used() || !cfs_rq->runtime_enabled)
+		return;
+
+	__account_cfs_rq_runtime(cfs_rq, delta_exec);
+}
+
+static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq)
+{
+	return cfs_bandwidth_used() && cfs_rq->throttled;
+}
+
+/* check whether cfs_rq, or any parent, is throttled */
+static inline int throttled_hierarchy(struct cfs_rq *cfs_rq)
+{
+	return cfs_bandwidth_used() && cfs_rq->throttle_count;
+}
+
+/*
+ * Ensure that neither of the group entities corresponding to src_cpu or
+ * dest_cpu are members of a throttled hierarchy when performing group
+ * load-balance operations.
+ */
+static inline int throttled_lb_pair(struct task_group *tg,
+				    int src_cpu, int dest_cpu)
+{
+	struct cfs_rq *src_cfs_rq, *dest_cfs_rq;
+
+	src_cfs_rq = tg->cfs_rq[src_cpu];
+	dest_cfs_rq = tg->cfs_rq[dest_cpu];
+
+	return throttled_hierarchy(src_cfs_rq) ||
+	       throttled_hierarchy(dest_cfs_rq);
+}
+
+static int tg_unthrottle_up(struct task_group *tg, void *data)
+{
+	struct rq *rq = data;
+	struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
+
+	cfs_rq->throttle_count--;
+	if (!cfs_rq->throttle_count) {
+		cfs_rq->throttled_clock_pelt_time += rq_clock_pelt(rq) -
+					     cfs_rq->throttled_clock_pelt;
+
+		/* Add cfs_rq with load or one or more already running entities to the list */
+		if (!cfs_rq_is_decayed(cfs_rq))
+			list_add_leaf_cfs_rq(cfs_rq);
+
+		if (cfs_rq->throttled_clock_self) {
+			u64 delta = rq_clock(rq) - cfs_rq->throttled_clock_self;
+
+			cfs_rq->throttled_clock_self = 0;
+
+			if (SCHED_WARN_ON((s64)delta < 0))
+				delta = 0;
+
+			cfs_rq->throttled_clock_self_time += delta;
+		}
+	}
+
+	return 0;
+}
+
+static int tg_throttle_down(struct task_group *tg, void *data)
+{
+	struct rq *rq = data;
+	struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
+
+	/* group is entering throttled state, stop time */
+	if (!cfs_rq->throttle_count) {
+		cfs_rq->throttled_clock_pelt = rq_clock_pelt(rq);
+		list_del_leaf_cfs_rq(cfs_rq);
+
+		SCHED_WARN_ON(cfs_rq->throttled_clock_self);
+		if (cfs_rq->nr_running)
+			cfs_rq->throttled_clock_self = rq_clock(rq);
+	}
+	cfs_rq->throttle_count++;
+
+	return 0;
+}
+
+static bool throttle_cfs_rq(struct cfs_rq *cfs_rq)
+{
+	struct rq *rq = rq_of(cfs_rq);
+	struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
+	struct sched_entity *se;
+	long task_delta, idle_task_delta, dequeue = 1;
+
+	raw_spin_lock(&cfs_b->lock);
+	/* This will start the period timer if necessary */
+	if (__assign_cfs_rq_runtime(cfs_b, cfs_rq, 1)) {
+		/*
+		 * We have raced with bandwidth becoming available, and if we
+		 * actually throttled the timer might not unthrottle us for an
+		 * entire period. We additionally needed to make sure that any
+		 * subsequent check_cfs_rq_runtime calls agree not to throttle
+		 * us, as we may commit to do cfs put_prev+pick_next, so we ask
+		 * for 1ns of runtime rather than just check cfs_b.
+		 */
+		dequeue = 0;
+	} else {
+		list_add_tail_rcu(&cfs_rq->throttled_list,
+				  &cfs_b->throttled_cfs_rq);
+	}
+	raw_spin_unlock(&cfs_b->lock);
+
+	if (!dequeue)
+		return false;  /* Throttle no longer required. */
+
+	se = cfs_rq->tg->se[cpu_of(rq_of(cfs_rq))];
+
+	/* freeze hierarchy runnable averages while throttled */
+	rcu_read_lock();
+	walk_tg_tree_from(cfs_rq->tg, tg_throttle_down, tg_nop, (void *)rq);
+	rcu_read_unlock();
+
+	task_delta = cfs_rq->h_nr_running;
+	idle_task_delta = cfs_rq->idle_h_nr_running;
+	for_each_sched_entity(se) {
+		struct cfs_rq *qcfs_rq = cfs_rq_of(se);
+		/* throttled entity or throttle-on-deactivate */
+		if (!se->on_rq)
+			goto done;
+
+		dequeue_entity(qcfs_rq, se, DEQUEUE_SLEEP);
+
+		if (cfs_rq_is_idle(group_cfs_rq(se)))
+			idle_task_delta = cfs_rq->h_nr_running;
+
+		qcfs_rq->h_nr_running -= task_delta;
+		qcfs_rq->idle_h_nr_running -= idle_task_delta;
+
+		if (qcfs_rq->load.weight) {
+			/* Avoid re-evaluating load for this entity: */
+			se = parent_entity(se);
+			break;
+		}
+	}
+
+	for_each_sched_entity(se) {
+		struct cfs_rq *qcfs_rq = cfs_rq_of(se);
+		/* throttled entity or throttle-on-deactivate */
+		if (!se->on_rq)
+			goto done;
+
+		update_load_avg(qcfs_rq, se, 0);
+		se_update_runnable(se);
+
+		if (cfs_rq_is_idle(group_cfs_rq(se)))
+			idle_task_delta = cfs_rq->h_nr_running;
+
+		qcfs_rq->h_nr_running -= task_delta;
+		qcfs_rq->idle_h_nr_running -= idle_task_delta;
+	}
+
+	/* At this point se is NULL and we are at root level*/
+	sub_nr_running(rq, task_delta);
+
+done:
+	/*
+	 * Note: distribution will already see us throttled via the
+	 * throttled-list.  rq->lock protects completion.
+	 */
+	cfs_rq->throttled = 1;
+	SCHED_WARN_ON(cfs_rq->throttled_clock);
+	if (cfs_rq->nr_running)
+		cfs_rq->throttled_clock = rq_clock(rq);
+	return true;
+}
+
+void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)
+{
+	struct rq *rq = rq_of(cfs_rq);
+	struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
+	struct sched_entity *se;
+	long task_delta, idle_task_delta;
+
+	se = cfs_rq->tg->se[cpu_of(rq)];
+
+	cfs_rq->throttled = 0;
+
+	update_rq_clock(rq);
+
+	raw_spin_lock(&cfs_b->lock);
+	if (cfs_rq->throttled_clock) {
+		cfs_b->throttled_time += rq_clock(rq) - cfs_rq->throttled_clock;
+		cfs_rq->throttled_clock = 0;
+	}
+	list_del_rcu(&cfs_rq->throttled_list);
+	raw_spin_unlock(&cfs_b->lock);
+
+	/* update hierarchical throttle state */
+	walk_tg_tree_from(cfs_rq->tg, tg_nop, tg_unthrottle_up, (void *)rq);
+
+	if (!cfs_rq->load.weight) {
+		if (!cfs_rq->on_list)
+			return;
+		/*
+		 * Nothing to run but something to decay (on_list)?
+		 * Complete the branch.
+		 */
+		for_each_sched_entity(se) {
+			if (list_add_leaf_cfs_rq(cfs_rq_of(se)))
+				break;
+		}
+		goto unthrottle_throttle;
+	}
+
+	task_delta = cfs_rq->h_nr_running;
+	idle_task_delta = cfs_rq->idle_h_nr_running;
+	for_each_sched_entity(se) {
+		struct cfs_rq *qcfs_rq = cfs_rq_of(se);
+
+		if (se->on_rq)
+			break;
+		enqueue_entity(qcfs_rq, se, ENQUEUE_WAKEUP);
+
+		if (cfs_rq_is_idle(group_cfs_rq(se)))
+			idle_task_delta = cfs_rq->h_nr_running;
+
+		qcfs_rq->h_nr_running += task_delta;
+		qcfs_rq->idle_h_nr_running += idle_task_delta;
+
+		/* end evaluation on encountering a throttled cfs_rq */
+		if (cfs_rq_throttled(qcfs_rq))
+			goto unthrottle_throttle;
+	}
+
+	for_each_sched_entity(se) {
+		struct cfs_rq *qcfs_rq = cfs_rq_of(se);
+
+		update_load_avg(qcfs_rq, se, UPDATE_TG);
+		se_update_runnable(se);
+
+		if (cfs_rq_is_idle(group_cfs_rq(se)))
+			idle_task_delta = cfs_rq->h_nr_running;
+
+		qcfs_rq->h_nr_running += task_delta;
+		qcfs_rq->idle_h_nr_running += idle_task_delta;
+
+		/* end evaluation on encountering a throttled cfs_rq */
+		if (cfs_rq_throttled(qcfs_rq))
+			goto unthrottle_throttle;
+	}
+
+	/* At this point se is NULL and we are at root level*/
+	add_nr_running(rq, task_delta);
+
+unthrottle_throttle:
+	assert_list_leaf_cfs_rq(rq);
+
+	/* Determine whether we need to wake up potentially idle CPU: */
+	if (rq->curr == rq->idle && rq->cfs.nr_running)
+		resched_curr(rq);
+}
+
+#ifdef CONFIG_SMP
+static void __cfsb_csd_unthrottle(void *arg)
+{
+	struct cfs_rq *cursor, *tmp;
+	struct rq *rq = arg;
+	struct rq_flags rf;
+
+	rq_lock(rq, &rf);
+
+	/*
+	 * Iterating over the list can trigger several call to
+	 * update_rq_clock() in unthrottle_cfs_rq().
+	 * Do it once and skip the potential next ones.
+	 */
+	update_rq_clock(rq);
+	rq_clock_start_loop_update(rq);
+
+	/*
+	 * Since we hold rq lock we're safe from concurrent manipulation of
+	 * the CSD list. However, this RCU critical section annotates the
+	 * fact that we pair with sched_free_group_rcu(), so that we cannot
+	 * race with group being freed in the window between removing it
+	 * from the list and advancing to the next entry in the list.
+	 */
+	rcu_read_lock();
+
+	list_for_each_entry_safe(cursor, tmp, &rq->cfsb_csd_list,
+				 throttled_csd_list) {
+		list_del_init(&cursor->throttled_csd_list);
+
+		if (cfs_rq_throttled(cursor))
+			unthrottle_cfs_rq(cursor);
+	}
+
+	rcu_read_unlock();
+
+	rq_clock_stop_loop_update(rq);
+	rq_unlock(rq, &rf);
+}
+
+static inline void __unthrottle_cfs_rq_async(struct cfs_rq *cfs_rq)
+{
+	struct rq *rq = rq_of(cfs_rq);
+	bool first;
+
+	if (rq == this_rq()) {
+		unthrottle_cfs_rq(cfs_rq);
+		return;
+	}
+
+	/* Already enqueued */
+	if (SCHED_WARN_ON(!list_empty(&cfs_rq->throttled_csd_list)))
+		return;
+
+	first = list_empty(&rq->cfsb_csd_list);
+	list_add_tail(&cfs_rq->throttled_csd_list, &rq->cfsb_csd_list);
+	if (first)
+		smp_call_function_single_async(cpu_of(rq), &rq->cfsb_csd);
+}
+#else
+static inline void __unthrottle_cfs_rq_async(struct cfs_rq *cfs_rq)
+{
+	unthrottle_cfs_rq(cfs_rq);
+}
+#endif
+
+static void unthrottle_cfs_rq_async(struct cfs_rq *cfs_rq)
+{
+	lockdep_assert_rq_held(rq_of(cfs_rq));
+
+	if (SCHED_WARN_ON(!cfs_rq_throttled(cfs_rq) ||
+	    cfs_rq->runtime_remaining <= 0))
+		return;
+
+	__unthrottle_cfs_rq_async(cfs_rq);
+}
+
+static bool distribute_cfs_runtime(struct cfs_bandwidth *cfs_b)
+{
+	struct cfs_rq *local_unthrottle = NULL;
+	int this_cpu = smp_processor_id();
+	u64 runtime, remaining = 1;
+	bool throttled = false;
+	struct cfs_rq *cfs_rq;
+	struct rq_flags rf;
+	struct rq *rq;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(cfs_rq, &cfs_b->throttled_cfs_rq,
+				throttled_list) {
+		rq = rq_of(cfs_rq);
+
+		if (!remaining) {
+			throttled = true;
+			break;
+		}
+
+		rq_lock_irqsave(rq, &rf);
+		if (!cfs_rq_throttled(cfs_rq))
+			goto next;
+
+#ifdef CONFIG_SMP
+		/* Already queued for async unthrottle */
+		if (!list_empty(&cfs_rq->throttled_csd_list))
+			goto next;
+#endif
+
+		/* By the above checks, this should never be true */
+		SCHED_WARN_ON(cfs_rq->runtime_remaining > 0);
+
+		raw_spin_lock(&cfs_b->lock);
+		runtime = -cfs_rq->runtime_remaining + 1;
+		if (runtime > cfs_b->runtime)
+			runtime = cfs_b->runtime;
+		cfs_b->runtime -= runtime;
+		remaining = cfs_b->runtime;
+		raw_spin_unlock(&cfs_b->lock);
+
+		cfs_rq->runtime_remaining += runtime;
+
+		/* we check whether we're throttled above */
+		if (cfs_rq->runtime_remaining > 0) {
+			if (cpu_of(rq) != this_cpu ||
+			    SCHED_WARN_ON(local_unthrottle))
+				unthrottle_cfs_rq_async(cfs_rq);
+			else
+				local_unthrottle = cfs_rq;
+		} else {
+			throttled = true;
+		}
+
+next:
+		rq_unlock_irqrestore(rq, &rf);
+	}
+	rcu_read_unlock();
+
+	if (local_unthrottle) {
+		rq = cpu_rq(this_cpu);
+		rq_lock_irqsave(rq, &rf);
+		if (cfs_rq_throttled(local_unthrottle))
+			unthrottle_cfs_rq(local_unthrottle);
+		rq_unlock_irqrestore(rq, &rf);
+	}
+
+	return throttled;
+}
+
+/*
+ * Responsible for refilling a task_group's bandwidth and unthrottling its
+ * cfs_rqs as appropriate. If there has been no activity within the last
+ * period the timer is deactivated until scheduling resumes; cfs_b->idle is
+ * used to track this state.
+ */
+static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun, unsigned long flags)
+{
+	int throttled;
+
+	/* no need to continue the timer with no bandwidth constraint */
+	if (cfs_b->quota == RUNTIME_INF)
+		goto out_deactivate;
+
+	throttled = !list_empty(&cfs_b->throttled_cfs_rq);
+	cfs_b->nr_periods += overrun;
+
+	/* Refill extra burst quota even if cfs_b->idle */
+	__refill_cfs_bandwidth_runtime(cfs_b);
+
+	/*
+	 * idle depends on !throttled (for the case of a large deficit), and if
+	 * we're going inactive then everything else can be deferred
+	 */
+	if (cfs_b->idle && !throttled)
+		goto out_deactivate;
+
+	if (!throttled) {
+		/* mark as potentially idle for the upcoming period */
+		cfs_b->idle = 1;
+		return 0;
+	}
+
+	/* account preceding periods in which throttling occurred */
+	cfs_b->nr_throttled += overrun;
+
+	/*
+	 * This check is repeated as we release cfs_b->lock while we unthrottle.
+	 */
+	while (throttled && cfs_b->runtime > 0) {
+		raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
+		/* we can't nest cfs_b->lock while distributing bandwidth */
+		throttled = distribute_cfs_runtime(cfs_b);
+		raw_spin_lock_irqsave(&cfs_b->lock, flags);
+	}
+
+	/*
+	 * While we are ensured activity in the period following an
+	 * unthrottle, this also covers the case in which the new bandwidth is
+	 * insufficient to cover the existing bandwidth deficit.  (Forcing the
+	 * timer to remain active while there are any throttled entities.)
+	 */
+	cfs_b->idle = 0;
+
+	return 0;
+
+out_deactivate:
+	return 1;
+}
+
+/* a cfs_rq won't donate quota below this amount */
+static const u64 min_cfs_rq_runtime = 1 * NSEC_PER_MSEC;
+/* minimum remaining period time to redistribute slack quota */
+static const u64 min_bandwidth_expiration = 2 * NSEC_PER_MSEC;
+/* how long we wait to gather additional slack before distributing */
+static const u64 cfs_bandwidth_slack_period = 5 * NSEC_PER_MSEC;
+
+/*
+ * Are we near the end of the current quota period?
+ *
+ * Requires cfs_b->lock for hrtimer_expires_remaining to be safe against the
+ * hrtimer base being cleared by hrtimer_start. In the case of
+ * migrate_hrtimers, base is never cleared, so we are fine.
+ */
+static int runtime_refresh_within(struct cfs_bandwidth *cfs_b, u64 min_expire)
+{
+	struct hrtimer *refresh_timer = &cfs_b->period_timer;
+	s64 remaining;
+
+	/* if the call-back is running a quota refresh is already occurring */
+	if (hrtimer_callback_running(refresh_timer))
+		return 1;
+
+	/* is a quota refresh about to occur? */
+	remaining = ktime_to_ns(hrtimer_expires_remaining(refresh_timer));
+	if (remaining < (s64)min_expire)
+		return 1;
+
+	return 0;
+}
+
+static void start_cfs_slack_bandwidth(struct cfs_bandwidth *cfs_b)
+{
+	u64 min_left = cfs_bandwidth_slack_period + min_bandwidth_expiration;
+
+	/* if there's a quota refresh soon don't bother with slack */
+	if (runtime_refresh_within(cfs_b, min_left))
+		return;
+
+	/* don't push forwards an existing deferred unthrottle */
+	if (cfs_b->slack_started)
+		return;
+	cfs_b->slack_started = true;
+
+	hrtimer_start(&cfs_b->slack_timer,
+			ns_to_ktime(cfs_bandwidth_slack_period),
+			HRTIMER_MODE_REL);
+}
+
+/* we know any runtime found here is valid as update_curr() precedes return */
+static void __return_cfs_rq_runtime(struct cfs_rq *cfs_rq)
+{
+	struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
+	s64 slack_runtime = cfs_rq->runtime_remaining - min_cfs_rq_runtime;
+
+	if (slack_runtime <= 0)
+		return;
+
+	raw_spin_lock(&cfs_b->lock);
+	if (cfs_b->quota != RUNTIME_INF) {
+		cfs_b->runtime += slack_runtime;
+
+		/* we are under rq->lock, defer unthrottling using a timer */
+		if (cfs_b->runtime > sched_cfs_bandwidth_slice() &&
+		    !list_empty(&cfs_b->throttled_cfs_rq))
+			start_cfs_slack_bandwidth(cfs_b);
+	}
+	raw_spin_unlock(&cfs_b->lock);
+
+	/* even if it's not valid for return we don't want to try again */
+	cfs_rq->runtime_remaining -= slack_runtime;
+}
+
+static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq)
+{
+	if (!cfs_bandwidth_used())
+		return;
+
+	if (!cfs_rq->runtime_enabled || cfs_rq->nr_running)
+		return;
+
+	__return_cfs_rq_runtime(cfs_rq);
+}
+
+/*
+ * This is done with a timer (instead of inline with bandwidth return) since
+ * it's necessary to juggle rq->locks to unthrottle their respective cfs_rqs.
+ */
+static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b)
+{
+	u64 runtime = 0, slice = sched_cfs_bandwidth_slice();
+	unsigned long flags;
+
+	/* confirm we're still not at a refresh boundary */
+	raw_spin_lock_irqsave(&cfs_b->lock, flags);
+	cfs_b->slack_started = false;
+
+	if (runtime_refresh_within(cfs_b, min_bandwidth_expiration)) {
+		raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
+		return;
+	}
+
+	if (cfs_b->quota != RUNTIME_INF && cfs_b->runtime > slice)
+		runtime = cfs_b->runtime;
+
+	raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
+
+	if (!runtime)
+		return;
+
+	distribute_cfs_runtime(cfs_b);
+}
+
+/*
+ * When a group wakes up we want to make sure that its quota is not already
+ * expired/exceeded, otherwise it may be allowed to steal additional ticks of
+ * runtime as update_curr() throttling can not trigger until it's on-rq.
+ */
+static void check_enqueue_throttle(struct cfs_rq *cfs_rq)
+{
+	if (!cfs_bandwidth_used())
+		return;
+
+	/* an active group must be handled by the update_curr()->put() path */
+	if (!cfs_rq->runtime_enabled || cfs_rq->curr)
+		return;
+
+	/* ensure the group is not already throttled */
+	if (cfs_rq_throttled(cfs_rq))
+		return;
+
+	/* update runtime allocation */
+	account_cfs_rq_runtime(cfs_rq, 0);
+	if (cfs_rq->runtime_remaining <= 0)
+		throttle_cfs_rq(cfs_rq);
+}
+
+static void sync_throttle(struct task_group *tg, int cpu)
+{
+	struct cfs_rq *pcfs_rq, *cfs_rq;
+
+	if (!cfs_bandwidth_used())
+		return;
+
+	if (!tg->parent)
+		return;
+
+	cfs_rq = tg->cfs_rq[cpu];
+	pcfs_rq = tg->parent->cfs_rq[cpu];
+
+	cfs_rq->throttle_count = pcfs_rq->throttle_count;
+	cfs_rq->throttled_clock_pelt = rq_clock_pelt(cpu_rq(cpu));
+}
+
+/* conditionally throttle active cfs_rq's from put_prev_entity() */
+static bool check_cfs_rq_runtime(struct cfs_rq *cfs_rq)
+{
+	if (!cfs_bandwidth_used())
+		return false;
+
+	if (likely(!cfs_rq->runtime_enabled || cfs_rq->runtime_remaining > 0))
+		return false;
+
+	/*
+	 * it's possible for a throttled entity to be forced into a running
+	 * state (e.g. set_curr_task), in this case we're finished.
+	 */
+	if (cfs_rq_throttled(cfs_rq))
+		return true;
+
+	return throttle_cfs_rq(cfs_rq);
+}
+
+static enum hrtimer_restart sched_cfs_slack_timer(struct hrtimer *timer)
+{
+	struct cfs_bandwidth *cfs_b =
+		container_of(timer, struct cfs_bandwidth, slack_timer);
+
+	do_sched_cfs_slack_timer(cfs_b);
+
+	return HRTIMER_NORESTART;
+}
+
+extern const u64 max_cfs_quota_period;
+
+static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer)
+{
+	struct cfs_bandwidth *cfs_b =
+		container_of(timer, struct cfs_bandwidth, period_timer);
+	unsigned long flags;
+	int overrun;
+	int idle = 0;
+	int count = 0;
+
+	raw_spin_lock_irqsave(&cfs_b->lock, flags);
+	for (;;) {
+		overrun = hrtimer_forward_now(timer, cfs_b->period);
+		if (!overrun)
+			break;
+
+		idle = do_sched_cfs_period_timer(cfs_b, overrun, flags);
+
+		if (++count > 3) {
+			u64 new, old = ktime_to_ns(cfs_b->period);
+
+			/*
+			 * Grow period by a factor of 2 to avoid losing precision.
+			 * Precision loss in the quota/period ratio can cause __cfs_schedulable
+			 * to fail.
+			 */
+			new = old * 2;
+			if (new < max_cfs_quota_period) {
+				cfs_b->period = ns_to_ktime(new);
+				cfs_b->quota *= 2;
+				cfs_b->burst *= 2;
+
+				pr_warn_ratelimited(
+	"cfs_period_timer[cpu%d]: period too short, scaling up (new cfs_period_us = %lld, cfs_quota_us = %lld)\n",
+					smp_processor_id(),
+					div_u64(new, NSEC_PER_USEC),
+					div_u64(cfs_b->quota, NSEC_PER_USEC));
+			} else {
+				pr_warn_ratelimited(
+	"cfs_period_timer[cpu%d]: period too short, but cannot scale up without losing precision (cfs_period_us = %lld, cfs_quota_us = %lld)\n",
+					smp_processor_id(),
+					div_u64(old, NSEC_PER_USEC),
+					div_u64(cfs_b->quota, NSEC_PER_USEC));
+			}
+
+			/* reset count so we don't come right back in here */
+			count = 0;
+		}
+	}
+	if (idle)
+		cfs_b->period_active = 0;
+	raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
+
+	return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
+}
+
+void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b, struct cfs_bandwidth *parent)
+{
+	raw_spin_lock_init(&cfs_b->lock);
+	cfs_b->runtime = 0;
+	cfs_b->quota = RUNTIME_INF;
+	cfs_b->period = ns_to_ktime(default_cfs_period());
+	cfs_b->burst = 0;
+	cfs_b->hierarchical_quota = parent ? parent->hierarchical_quota : RUNTIME_INF;
+
+	INIT_LIST_HEAD(&cfs_b->throttled_cfs_rq);
+	hrtimer_init(&cfs_b->period_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
+	cfs_b->period_timer.function = sched_cfs_period_timer;
+
+	/* Add a random offset so that timers interleave */
+	hrtimer_set_expires(&cfs_b->period_timer,
+			    get_random_u32_below(cfs_b->period));
+	hrtimer_init(&cfs_b->slack_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	cfs_b->slack_timer.function = sched_cfs_slack_timer;
+	cfs_b->slack_started = false;
+}
+
+static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq)
+{
+	cfs_rq->runtime_enabled = 0;
+	INIT_LIST_HEAD(&cfs_rq->throttled_list);
+#ifdef CONFIG_SMP
+	INIT_LIST_HEAD(&cfs_rq->throttled_csd_list);
+#endif
+}
+
+void start_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
+{
+	lockdep_assert_held(&cfs_b->lock);
+
+	if (cfs_b->period_active)
+		return;
+
+	cfs_b->period_active = 1;
+	hrtimer_forward_now(&cfs_b->period_timer, cfs_b->period);
+	hrtimer_start_expires(&cfs_b->period_timer, HRTIMER_MODE_ABS_PINNED);
+}
+
+static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
+{
+	int __maybe_unused i;
+
+	/* init_cfs_bandwidth() was not called */
+	if (!cfs_b->throttled_cfs_rq.next)
+		return;
+
+	hrtimer_cancel(&cfs_b->period_timer);
+	hrtimer_cancel(&cfs_b->slack_timer);
+
+	/*
+	 * It is possible that we still have some cfs_rq's pending on a CSD
+	 * list, though this race is very rare. In order for this to occur, we
+	 * must have raced with the last task leaving the group while there
+	 * exist throttled cfs_rq(s), and the period_timer must have queued the
+	 * CSD item but the remote cpu has not yet processed it. To handle this,
+	 * we can simply flush all pending CSD work inline here. We're
+	 * guaranteed at this point that no additional cfs_rq of this group can
+	 * join a CSD list.
+	 */
+#ifdef CONFIG_SMP
+	for_each_possible_cpu(i) {
+		struct rq *rq = cpu_rq(i);
+		unsigned long flags;
+
+		if (list_empty(&rq->cfsb_csd_list))
+			continue;
+
+		local_irq_save(flags);
+		__cfsb_csd_unthrottle(rq);
+		local_irq_restore(flags);
+	}
+#endif
+}
+
+/*
+ * Both these CPU hotplug callbacks race against unregister_fair_sched_group()
+ *
+ * The race is harmless, since modifying bandwidth settings of unhooked group
+ * bits doesn't do much.
+ */
+
+/* cpu online callback */
+static void __maybe_unused update_runtime_enabled(struct rq *rq)
+{
+	struct task_group *tg;
+
+	lockdep_assert_rq_held(rq);
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(tg, &task_groups, list) {
+		struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
+		struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
+
+		raw_spin_lock(&cfs_b->lock);
+		cfs_rq->runtime_enabled = cfs_b->quota != RUNTIME_INF;
+		raw_spin_unlock(&cfs_b->lock);
+	}
+	rcu_read_unlock();
+}
+
+/* cpu offline callback */
+static void __maybe_unused unthrottle_offline_cfs_rqs(struct rq *rq)
+{
+	struct task_group *tg;
+
+	lockdep_assert_rq_held(rq);
+
+	/*
+	 * The rq clock has already been updated in the
+	 * set_rq_offline(), so we should skip updating
+	 * the rq clock again in unthrottle_cfs_rq().
+	 */
+	rq_clock_start_loop_update(rq);
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(tg, &task_groups, list) {
+		struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
+
+		if (!cfs_rq->runtime_enabled)
+			continue;
+
+		/*
+		 * clock_task is not advancing so we just need to make sure
+		 * there's some valid quota amount
+		 */
+		cfs_rq->runtime_remaining = 1;
+		/*
+		 * Offline rq is schedulable till CPU is completely disabled
+		 * in take_cpu_down(), so we prevent new cfs throttling here.
+		 */
+		cfs_rq->runtime_enabled = 0;
+
+		if (cfs_rq_throttled(cfs_rq))
+			unthrottle_cfs_rq(cfs_rq);
+	}
+	rcu_read_unlock();
+
+	rq_clock_stop_loop_update(rq);
+}
+
+bool cfs_task_bw_constrained(struct task_struct *p)
+{
+	struct cfs_rq *cfs_rq = task_cfs_rq(p);
+
+	if (!cfs_bandwidth_used())
+		return false;
+
+	if (cfs_rq->runtime_enabled ||
+	    tg_cfs_bandwidth(cfs_rq->tg)->hierarchical_quota != RUNTIME_INF)
+		return true;
+
+	return false;
+}
+
+#ifdef CONFIG_NO_HZ_FULL
+/* called from pick_next_task_fair() */
+static void sched_fair_update_stop_tick(struct rq *rq, struct task_struct *p)
+{
+	int cpu = cpu_of(rq);
+
+	if (!sched_feat(HZ_BW) || !cfs_bandwidth_used())
+		return;
+
+	if (!tick_nohz_full_cpu(cpu))
+		return;
+
+	if (rq->nr_running != 1)
+		return;
+
+	/*
+	 *  We know there is only one task runnable and we've just picked it. The
+	 *  normal enqueue path will have cleared TICK_DEP_BIT_SCHED if we will
+	 *  be otherwise able to stop the tick. Just need to check if we are using
+	 *  bandwidth control.
+	 */
+	if (cfs_task_bw_constrained(p))
+		tick_nohz_dep_set_cpu(cpu, TICK_DEP_BIT_SCHED);
+}
+#endif
+
+#else /* CONFIG_CFS_BANDWIDTH */
+
+static inline bool cfs_bandwidth_used(void)
+{
+	return false;
+}
+
+static void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec) {}
+static bool check_cfs_rq_runtime(struct cfs_rq *cfs_rq) { return false; }
+static void check_enqueue_throttle(struct cfs_rq *cfs_rq) {}
+static inline void sync_throttle(struct task_group *tg, int cpu) {}
+static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq) {}
+
+static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq)
+{
+	return 0;
+}
+
+static inline int throttled_hierarchy(struct cfs_rq *cfs_rq)
+{
+	return 0;
+}
+
+static inline int throttled_lb_pair(struct task_group *tg,
+				    int src_cpu, int dest_cpu)
+{
+	return 0;
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b, struct cfs_bandwidth *parent) {}
+static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq) {}
+#endif
+
+static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg)
+{
+	return NULL;
+}
+static inline void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
+static inline void update_runtime_enabled(struct rq *rq) {}
+static inline void unthrottle_offline_cfs_rqs(struct rq *rq) {}
+#ifdef CONFIG_CGROUP_SCHED
+bool cfs_task_bw_constrained(struct task_struct *p)
+{
+	return false;
+}
+#endif
+#endif /* CONFIG_CFS_BANDWIDTH */
+
+#if !defined(CONFIG_CFS_BANDWIDTH) || !defined(CONFIG_NO_HZ_FULL)
+static inline void sched_fair_update_stop_tick(struct rq *rq, struct task_struct *p) {}
+#endif
+
+/**************************************************
+ * CFS operations on tasks:
+ */
+
+#ifdef CONFIG_SCHED_HRTICK
+static void hrtick_start_fair(struct rq *rq, struct task_struct *p)
+{
+	struct sched_entity *se = &p->se;
+
+	SCHED_WARN_ON(task_rq(p) != rq);
+
+	if (rq->cfs.h_nr_running > 1) {
+		u64 ran = se->sum_exec_runtime - se->prev_sum_exec_runtime;
+		u64 slice = se->slice;
+		s64 delta = slice - ran;
+
+		if (delta < 0) {
+			if (task_current(rq, p))
+				resched_curr(rq);
+			return;
+		}
+		hrtick_start(rq, delta);
+	}
+}
+
+/*
+ * called from enqueue/dequeue and updates the hrtick when the
+ * current task is from our class and nr_running is low enough
+ * to matter.
+ */
+static void hrtick_update(struct rq *rq)
+{
+	struct task_struct *curr = rq->curr;
+
+	if (!hrtick_enabled_fair(rq) || curr->sched_class != &fair_sched_class)
+		return;
+
+	hrtick_start_fair(rq, curr);
+}
+#else /* !CONFIG_SCHED_HRTICK */
+static inline void
+hrtick_start_fair(struct rq *rq, struct task_struct *p)
+{
+}
+
+static inline void hrtick_update(struct rq *rq)
+{
+}
+#endif
+
+#ifdef CONFIG_SMP
+static inline bool cpu_overutilized(int cpu)
+{
+	unsigned long rq_util_min = uclamp_rq_get(cpu_rq(cpu), UCLAMP_MIN);
+	unsigned long rq_util_max = uclamp_rq_get(cpu_rq(cpu), UCLAMP_MAX);
+
+	/* Return true only if the utilization doesn't fit CPU's capacity */
+	return !util_fits_cpu(cpu_util_cfs(cpu), rq_util_min, rq_util_max, cpu);
+}
+
+static inline void update_overutilized_status(struct rq *rq)
+{
+	if (!READ_ONCE(rq->rd->overutilized) && cpu_overutilized(rq->cpu)) {
+		WRITE_ONCE(rq->rd->overutilized, SG_OVERUTILIZED);
+		trace_sched_overutilized_tp(rq->rd, SG_OVERUTILIZED);
+	}
+}
+#else
+static inline void update_overutilized_status(struct rq *rq) { }
+#endif
+
+/* Runqueue only has SCHED_IDLE tasks enqueued */
+static int sched_idle_rq(struct rq *rq)
+{
+	return unlikely(rq->nr_running == rq->cfs.idle_h_nr_running &&
+			rq->nr_running);
+}
+
+#ifdef CONFIG_SMP
+static int sched_idle_cpu(int cpu)
+{
+	return sched_idle_rq(cpu_rq(cpu));
+}
+#endif
+
+/*
+ * The enqueue_task method is called before nr_running is
+ * increased. Here we update the fair scheduling stats and
+ * then put the task into the rbtree:
+ */
+static void
+enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
+{
+	struct cfs_rq *cfs_rq;
+	struct sched_entity *se = &p->se;
+	int idle_h_nr_running = task_has_idle_policy(p);
+	int task_new = !(flags & ENQUEUE_WAKEUP);
+
+	/*
+	 * The code below (indirectly) updates schedutil which looks at
+	 * the cfs_rq utilization to select a frequency.
+	 * Let's add the task's estimated utilization to the cfs_rq's
+	 * estimated utilization, before we update schedutil.
+	 */
+	util_est_enqueue(&rq->cfs, p);
+
+	/*
+	 * If in_iowait is set, the code below may not trigger any cpufreq
+	 * utilization updates, so do it here explicitly with the IOWAIT flag
+	 * passed.
+	 */
+	if (p->in_iowait)
+		cpufreq_update_util(rq, SCHED_CPUFREQ_IOWAIT);
+
+	for_each_sched_entity(se) {
+		if (se->on_rq)
+			break;
+		cfs_rq = cfs_rq_of(se);
+		enqueue_entity(cfs_rq, se, flags);
+
+		cfs_rq->h_nr_running++;
+		cfs_rq->idle_h_nr_running += idle_h_nr_running;
+
+		if (cfs_rq_is_idle(cfs_rq))
+			idle_h_nr_running = 1;
+
+		/* end evaluation on encountering a throttled cfs_rq */
+		if (cfs_rq_throttled(cfs_rq))
+			goto enqueue_throttle;
+
+		flags = ENQUEUE_WAKEUP;
+	}
+
+	for_each_sched_entity(se) {
+		cfs_rq = cfs_rq_of(se);
+
+		update_load_avg(cfs_rq, se, UPDATE_TG);
+		se_update_runnable(se);
+		update_cfs_group(se);
+
+		cfs_rq->h_nr_running++;
+		cfs_rq->idle_h_nr_running += idle_h_nr_running;
+
+		if (cfs_rq_is_idle(cfs_rq))
+			idle_h_nr_running = 1;
+
+		/* end evaluation on encountering a throttled cfs_rq */
+		if (cfs_rq_throttled(cfs_rq))
+			goto enqueue_throttle;
+	}
+
+	/* At this point se is NULL and we are at root level*/
+	add_nr_running(rq, 1);
+
+	/*
+	 * Since new tasks are assigned an initial util_avg equal to
+	 * half of the spare capacity of their CPU, tiny tasks have the
+	 * ability to cross the overutilized threshold, which will
+	 * result in the load balancer ruining all the task placement
+	 * done by EAS. As a way to mitigate that effect, do not account
+	 * for the first enqueue operation of new tasks during the
+	 * overutilized flag detection.
+	 *
+	 * A better way of solving this problem would be to wait for
+	 * the PELT signals of tasks to converge before taking them
+	 * into account, but that is not straightforward to implement,
+	 * and the following generally works well enough in practice.
+	 */
+	if (!task_new)
+		update_overutilized_status(rq);
+
+enqueue_throttle:
+	assert_list_leaf_cfs_rq(rq);
+
+	hrtick_update(rq);
+}
+
+static void set_next_buddy(struct sched_entity *se);
+
+/*
+ * The dequeue_task method is called before nr_running is
+ * decreased. We remove the task from the rbtree and
+ * update the fair scheduling stats:
+ */
+static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
+{
+	struct cfs_rq *cfs_rq;
+	struct sched_entity *se = &p->se;
+	int task_sleep = flags & DEQUEUE_SLEEP;
+	int idle_h_nr_running = task_has_idle_policy(p);
+	bool was_sched_idle = sched_idle_rq(rq);
+
+	util_est_dequeue(&rq->cfs, p);
+
+	for_each_sched_entity(se) {
+		cfs_rq = cfs_rq_of(se);
+		dequeue_entity(cfs_rq, se, flags);
+
+		cfs_rq->h_nr_running--;
+		cfs_rq->idle_h_nr_running -= idle_h_nr_running;
+
+		if (cfs_rq_is_idle(cfs_rq))
+			idle_h_nr_running = 1;
+
+		/* end evaluation on encountering a throttled cfs_rq */
+		if (cfs_rq_throttled(cfs_rq))
+			goto dequeue_throttle;
+
+		/* Don't dequeue parent if it has other entities besides us */
+		if (cfs_rq->load.weight) {
+			/* Avoid re-evaluating load for this entity: */
+			se = parent_entity(se);
+			/*
+			 * Bias pick_next to pick a task from this cfs_rq, as
+			 * p is sleeping when it is within its sched_slice.
+			 */
+			if (task_sleep && se && !throttled_hierarchy(cfs_rq))
+				set_next_buddy(se);
+			break;
+		}
+		flags |= DEQUEUE_SLEEP;
+	}
+
+	for_each_sched_entity(se) {
+		cfs_rq = cfs_rq_of(se);
+
+		update_load_avg(cfs_rq, se, UPDATE_TG);
+		se_update_runnable(se);
+		update_cfs_group(se);
+
+		cfs_rq->h_nr_running--;
+		cfs_rq->idle_h_nr_running -= idle_h_nr_running;
+
+		if (cfs_rq_is_idle(cfs_rq))
+			idle_h_nr_running = 1;
+
+		/* end evaluation on encountering a throttled cfs_rq */
+		if (cfs_rq_throttled(cfs_rq))
+			goto dequeue_throttle;
+
+	}
+
+	/* At this point se is NULL and we are at root level*/
+	sub_nr_running(rq, 1);
+
+	/* balance early to pull high priority tasks */
+	if (unlikely(!was_sched_idle && sched_idle_rq(rq)))
+		rq->next_balance = jiffies;
+
+dequeue_throttle:
+	util_est_update(&rq->cfs, p, task_sleep);
+	hrtick_update(rq);
+}
+
+#ifdef CONFIG_SMP
+
+/* Working cpumask for: load_balance, load_balance_newidle. */
+static DEFINE_PER_CPU(cpumask_var_t, load_balance_mask);
+static DEFINE_PER_CPU(cpumask_var_t, select_rq_mask);
+static DEFINE_PER_CPU(cpumask_var_t, should_we_balance_tmpmask);
+
+#ifdef CONFIG_NO_HZ_COMMON
+
+static struct {
+	cpumask_var_t idle_cpus_mask;
+	atomic_t nr_cpus;
+	int has_blocked;		/* Idle CPUS has blocked load */
+	int needs_update;		/* Newly idle CPUs need their next_balance collated */
+	unsigned long next_balance;     /* in jiffy units */
+	unsigned long next_blocked;	/* Next update of blocked load in jiffies */
+} nohz ____cacheline_aligned;
+
+#endif /* CONFIG_NO_HZ_COMMON */
+
+static unsigned long cpu_load(struct rq *rq)
+{
+	return cfs_rq_load_avg(&rq->cfs);
+}
+
+/*
+ * cpu_load_without - compute CPU load without any contributions from *p
+ * @cpu: the CPU which load is requested
+ * @p: the task which load should be discounted
+ *
+ * The load of a CPU is defined by the load of tasks currently enqueued on that
+ * CPU as well as tasks which are currently sleeping after an execution on that
+ * CPU.
+ *
+ * This method returns the load of the specified CPU by discounting the load of
+ * the specified task, whenever the task is currently contributing to the CPU
+ * load.
+ */
+static unsigned long cpu_load_without(struct rq *rq, struct task_struct *p)
+{
+	struct cfs_rq *cfs_rq;
+	unsigned int load;
+
+	/* Task has no contribution or is new */
+	if (cpu_of(rq) != task_cpu(p) || !READ_ONCE(p->se.avg.last_update_time))
+		return cpu_load(rq);
+
+	cfs_rq = &rq->cfs;
+	load = READ_ONCE(cfs_rq->avg.load_avg);
+
+	/* Discount task's util from CPU's util */
+	lsub_positive(&load, task_h_load(p));
+
+	return load;
+}
+
+static unsigned long cpu_runnable(struct rq *rq)
+{
+	return cfs_rq_runnable_avg(&rq->cfs);
+}
+
+static unsigned long cpu_runnable_without(struct rq *rq, struct task_struct *p)
+{
+	struct cfs_rq *cfs_rq;
+	unsigned int runnable;
+
+	/* Task has no contribution or is new */
+	if (cpu_of(rq) != task_cpu(p) || !READ_ONCE(p->se.avg.last_update_time))
+		return cpu_runnable(rq);
+
+	cfs_rq = &rq->cfs;
+	runnable = READ_ONCE(cfs_rq->avg.runnable_avg);
+
+	/* Discount task's runnable from CPU's runnable */
+	lsub_positive(&runnable, p->se.avg.runnable_avg);
+
+	return runnable;
+}
+
+static unsigned long capacity_of(int cpu)
+{
+	return cpu_rq(cpu)->cpu_capacity;
+}
+
+static void record_wakee(struct task_struct *p)
+{
+	/*
+	 * Only decay a single time; tasks that have less then 1 wakeup per
+	 * jiffy will not have built up many flips.
+	 */
+	if (time_after(jiffies, current->wakee_flip_decay_ts + HZ)) {
+		current->wakee_flips >>= 1;
+		current->wakee_flip_decay_ts = jiffies;
+	}
+
+	if (current->last_wakee != p) {
+		current->last_wakee = p;
+		current->wakee_flips++;
+	}
+}
+
+/*
+ * Detect M:N waker/wakee relationships via a switching-frequency heuristic.
+ *
+ * A waker of many should wake a different task than the one last awakened
+ * at a frequency roughly N times higher than one of its wakees.
+ *
+ * In order to determine whether we should let the load spread vs consolidating
+ * to shared cache, we look for a minimum 'flip' frequency of llc_size in one
+ * partner, and a factor of lls_size higher frequency in the other.
+ *
+ * With both conditions met, we can be relatively sure that the relationship is
+ * non-monogamous, with partner count exceeding socket size.
+ *
+ * Waker/wakee being client/server, worker/dispatcher, interrupt source or
+ * whatever is irrelevant, spread criteria is apparent partner count exceeds
+ * socket size.
+ */
+static int wake_wide(struct task_struct *p)
+{
+	unsigned int master = current->wakee_flips;
+	unsigned int slave = p->wakee_flips;
+	int factor = __this_cpu_read(sd_llc_size);
+
+	if (master < slave)
+		swap(master, slave);
+	if (slave < factor || master < slave * factor)
+		return 0;
+	return 1;
+}
+
+/*
+ * The purpose of wake_affine() is to quickly determine on which CPU we can run
+ * soonest. For the purpose of speed we only consider the waking and previous
+ * CPU.
+ *
+ * wake_affine_idle() - only considers 'now', it check if the waking CPU is
+ *			cache-affine and is (or	will be) idle.
+ *
+ * wake_affine_weight() - considers the weight to reflect the average
+ *			  scheduling latency of the CPUs. This seems to work
+ *			  for the overloaded case.
+ */
+static int
+wake_affine_idle(int this_cpu, int prev_cpu, int sync)
+{
+	/*
+	 * If this_cpu is idle, it implies the wakeup is from interrupt
+	 * context. Only allow the move if cache is shared. Otherwise an
+	 * interrupt intensive workload could force all tasks onto one
+	 * node depending on the IO topology or IRQ affinity settings.
+	 *
+	 * If the prev_cpu is idle and cache affine then avoid a migration.
+	 * There is no guarantee that the cache hot data from an interrupt
+	 * is more important than cache hot data on the prev_cpu and from
+	 * a cpufreq perspective, it's better to have higher utilisation
+	 * on one CPU.
+	 */
+	if (available_idle_cpu(this_cpu) && cpus_share_cache(this_cpu, prev_cpu))
+		return available_idle_cpu(prev_cpu) ? prev_cpu : this_cpu;
+
+	if (sync && cpu_rq(this_cpu)->nr_running == 1)
+		return this_cpu;
+
+	if (available_idle_cpu(prev_cpu))
+		return prev_cpu;
+
+	return nr_cpumask_bits;
+}
+
+static int
+wake_affine_weight(struct sched_domain *sd, struct task_struct *p,
+		   int this_cpu, int prev_cpu, int sync)
+{
+	s64 this_eff_load, prev_eff_load;
+	unsigned long task_load;
+
+	this_eff_load = cpu_load(cpu_rq(this_cpu));
+
+	if (sync) {
+		unsigned long current_load = task_h_load(current);
+
+		if (current_load > this_eff_load)
+			return this_cpu;
+
+		this_eff_load -= current_load;
+	}
+
+	task_load = task_h_load(p);
+
+	this_eff_load += task_load;
+	if (sched_feat(WA_BIAS))
+		this_eff_load *= 100;
+	this_eff_load *= capacity_of(prev_cpu);
+
+	prev_eff_load = cpu_load(cpu_rq(prev_cpu));
+	prev_eff_load -= task_load;
+	if (sched_feat(WA_BIAS))
+		prev_eff_load *= 100 + (sd->imbalance_pct - 100) / 2;
+	prev_eff_load *= capacity_of(this_cpu);
+
+	/*
+	 * If sync, adjust the weight of prev_eff_load such that if
+	 * prev_eff == this_eff that select_idle_sibling() will consider
+	 * stacking the wakee on top of the waker if no other CPU is
+	 * idle.
+	 */
+	if (sync)
+		prev_eff_load += 1;
+
+	return this_eff_load < prev_eff_load ? this_cpu : nr_cpumask_bits;
+}
+
+static int wake_affine(struct sched_domain *sd, struct task_struct *p,
+		       int this_cpu, int prev_cpu, int sync)
+{
+	int target = nr_cpumask_bits;
+
+	if (sched_feat(WA_IDLE))
+		target = wake_affine_idle(this_cpu, prev_cpu, sync);
+
+	if (sched_feat(WA_WEIGHT) && target == nr_cpumask_bits)
+		target = wake_affine_weight(sd, p, this_cpu, prev_cpu, sync);
+
+	schedstat_inc(p->stats.nr_wakeups_affine_attempts);
+	if (target != this_cpu)
+		return prev_cpu;
+
+	schedstat_inc(sd->ttwu_move_affine);
+	schedstat_inc(p->stats.nr_wakeups_affine);
+	return target;
+}
+
+static struct sched_group *
+find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu);
+
+/*
+ * find_idlest_group_cpu - find the idlest CPU among the CPUs in the group.
+ */
+static int
+find_idlest_group_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
+{
+	unsigned long load, min_load = ULONG_MAX;
+	unsigned int min_exit_latency = UINT_MAX;
+	u64 latest_idle_timestamp = 0;
+	int least_loaded_cpu = this_cpu;
+	int shallowest_idle_cpu = -1;
+	int i;
+
+	/* Check if we have any choice: */
+	if (group->group_weight == 1)
+		return cpumask_first(sched_group_span(group));
+
+	/* Traverse only the allowed CPUs */
+	for_each_cpu_and(i, sched_group_span(group), p->cpus_ptr) {
+		struct rq *rq = cpu_rq(i);
+
+		if (!sched_core_cookie_match(rq, p))
+			continue;
+
+		if (sched_idle_cpu(i))
+			return i;
+
+		if (available_idle_cpu(i)) {
+			struct cpuidle_state *idle = idle_get_state(rq);
+			if (idle && idle->exit_latency < min_exit_latency) {
+				/*
+				 * We give priority to a CPU whose idle state
+				 * has the smallest exit latency irrespective
+				 * of any idle timestamp.
+				 */
+				min_exit_latency = idle->exit_latency;
+				latest_idle_timestamp = rq->idle_stamp;
+				shallowest_idle_cpu = i;
+			} else if ((!idle || idle->exit_latency == min_exit_latency) &&
+				   rq->idle_stamp > latest_idle_timestamp) {
+				/*
+				 * If equal or no active idle state, then
+				 * the most recently idled CPU might have
+				 * a warmer cache.
+				 */
+				latest_idle_timestamp = rq->idle_stamp;
+				shallowest_idle_cpu = i;
+			}
+		} else if (shallowest_idle_cpu == -1) {
+			load = cpu_load(cpu_rq(i));
+			if (load < min_load) {
+				min_load = load;
+				least_loaded_cpu = i;
+			}
+		}
+	}
+
+	return shallowest_idle_cpu != -1 ? shallowest_idle_cpu : least_loaded_cpu;
+}
+
+static inline int find_idlest_cpu(struct sched_domain *sd, struct task_struct *p,
+				  int cpu, int prev_cpu, int sd_flag)
+{
+	int new_cpu = cpu;
+
+	if (!cpumask_intersects(sched_domain_span(sd), p->cpus_ptr))
+		return prev_cpu;
+
+	/*
+	 * We need task's util for cpu_util_without, sync it up to
+	 * prev_cpu's last_update_time.
+	 */
+	if (!(sd_flag & SD_BALANCE_FORK))
+		sync_entity_load_avg(&p->se);
+
+	while (sd) {
+		struct sched_group *group;
+		struct sched_domain *tmp;
+		int weight;
+
+		if (!(sd->flags & sd_flag)) {
+			sd = sd->child;
+			continue;
+		}
+
+		group = find_idlest_group(sd, p, cpu);
+		if (!group) {
+			sd = sd->child;
+			continue;
+		}
+
+		new_cpu = find_idlest_group_cpu(group, p, cpu);
+		if (new_cpu == cpu) {
+			/* Now try balancing at a lower domain level of 'cpu': */
+			sd = sd->child;
+			continue;
+		}
+
+		/* Now try balancing at a lower domain level of 'new_cpu': */
+		cpu = new_cpu;
+		weight = sd->span_weight;
+		sd = NULL;
+		for_each_domain(cpu, tmp) {
+			if (weight <= tmp->span_weight)
+				break;
+			if (tmp->flags & sd_flag)
+				sd = tmp;
+		}
+	}
+
+	return new_cpu;
+}
+
+static inline int __select_idle_cpu(int cpu, struct task_struct *p)
+{
+	if ((available_idle_cpu(cpu) || sched_idle_cpu(cpu)) &&
+	    sched_cpu_cookie_match(cpu_rq(cpu), p))
+		return cpu;
+
+	return -1;
+}
+
+#ifdef CONFIG_SCHED_SMT
+DEFINE_STATIC_KEY_FALSE(sched_smt_present);
+EXPORT_SYMBOL_GPL(sched_smt_present);
+
+static inline void set_idle_cores(int cpu, int val)
+{
+	struct sched_domain_shared *sds;
+
+	sds = rcu_dereference(per_cpu(sd_llc_shared, cpu));
+	if (sds)
+		WRITE_ONCE(sds->has_idle_cores, val);
+}
+
+static inline bool test_idle_cores(int cpu)
+{
+	struct sched_domain_shared *sds;
+
+	sds = rcu_dereference(per_cpu(sd_llc_shared, cpu));
+	if (sds)
+		return READ_ONCE(sds->has_idle_cores);
+
+	return false;
+}
+
+/*
+ * Scans the local SMT mask to see if the entire core is idle, and records this
+ * information in sd_llc_shared->has_idle_cores.
+ *
+ * Since SMT siblings share all cache levels, inspecting this limited remote
+ * state should be fairly cheap.
+ */
+void __update_idle_core(struct rq *rq)
+{
+	int core = cpu_of(rq);
+	int cpu;
+
+	rcu_read_lock();
+	if (test_idle_cores(core))
+		goto unlock;
+
+	for_each_cpu(cpu, cpu_smt_mask(core)) {
+		if (cpu == core)
+			continue;
+
+		if (!available_idle_cpu(cpu))
+			goto unlock;
+	}
+
+	set_idle_cores(core, 1);
+unlock:
+	rcu_read_unlock();
+}
+
+/*
+ * Scan the entire LLC domain for idle cores; this dynamically switches off if
+ * there are no idle cores left in the system; tracked through
+ * sd_llc->shared->has_idle_cores and enabled through update_idle_core() above.
+ */
+static int select_idle_core(struct task_struct *p, int core, struct cpumask *cpus, int *idle_cpu)
+{
+	bool idle = true;
+	int cpu;
+
+	for_each_cpu(cpu, cpu_smt_mask(core)) {
+		if (!available_idle_cpu(cpu)) {
+			idle = false;
+			if (*idle_cpu == -1) {
+				if (sched_idle_cpu(cpu) && cpumask_test_cpu(cpu, p->cpus_ptr)) {
+					*idle_cpu = cpu;
+					break;
+				}
+				continue;
+			}
+			break;
+		}
+		if (*idle_cpu == -1 && cpumask_test_cpu(cpu, p->cpus_ptr))
+			*idle_cpu = cpu;
+	}
+
+	if (idle)
+		return core;
+
+	cpumask_andnot(cpus, cpus, cpu_smt_mask(core));
+	return -1;
+}
+
+/*
+ * Scan the local SMT mask for idle CPUs.
+ */
+static int select_idle_smt(struct task_struct *p, int target)
+{
+	int cpu;
+
+	for_each_cpu_and(cpu, cpu_smt_mask(target), p->cpus_ptr) {
+		if (cpu == target)
+			continue;
+		if (available_idle_cpu(cpu) || sched_idle_cpu(cpu))
+			return cpu;
+	}
+
+	return -1;
+}
+
+#else /* CONFIG_SCHED_SMT */
+
+static inline void set_idle_cores(int cpu, int val)
+{
+}
+
+static inline bool test_idle_cores(int cpu)
+{
+	return false;
+}
+
+static inline int select_idle_core(struct task_struct *p, int core, struct cpumask *cpus, int *idle_cpu)
+{
+	return __select_idle_cpu(core, p);
+}
+
+static inline int select_idle_smt(struct task_struct *p, int target)
+{
+	return -1;
+}
+
+#endif /* CONFIG_SCHED_SMT */
+
+/*
+ * Scan the LLC domain for idle CPUs; this is dynamically regulated by
+ * comparing the average scan cost (tracked in sd->avg_scan_cost) against the
+ * average idle time for this rq (as found in rq->avg_idle).
+ */
+static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool has_idle_core, int target)
+{
+	struct cpumask *cpus = this_cpu_cpumask_var_ptr(select_rq_mask);
+	int i, cpu, idle_cpu = -1, nr = INT_MAX;
+	struct sched_domain_shared *sd_share;
+	struct rq *this_rq = this_rq();
+	int this = smp_processor_id();
+	struct sched_domain *this_sd = NULL;
+	u64 time = 0;
+
+	cpumask_and(cpus, sched_domain_span(sd), p->cpus_ptr);
+
+	if (sched_feat(SIS_PROP) && !has_idle_core) {
+		u64 avg_cost, avg_idle, span_avg;
+		unsigned long now = jiffies;
+
+		this_sd = rcu_dereference(*this_cpu_ptr(&sd_llc));
+		if (!this_sd)
+			return -1;
+
+		/*
+		 * If we're busy, the assumption that the last idle period
+		 * predicts the future is flawed; age away the remaining
+		 * predicted idle time.
+		 */
+		if (unlikely(this_rq->wake_stamp < now)) {
+			while (this_rq->wake_stamp < now && this_rq->wake_avg_idle) {
+				this_rq->wake_stamp++;
+				this_rq->wake_avg_idle >>= 1;
+			}
+		}
+
+		avg_idle = this_rq->wake_avg_idle;
+		avg_cost = this_sd->avg_scan_cost + 1;
+
+		span_avg = sd->span_weight * avg_idle;
+		if (span_avg > 4*avg_cost)
+			nr = div_u64(span_avg, avg_cost);
+		else
+			nr = 4;
+
+		time = cpu_clock(this);
+	}
+
+	if (sched_feat(SIS_UTIL)) {
+		sd_share = rcu_dereference(per_cpu(sd_llc_shared, target));
+		if (sd_share) {
+			/* because !--nr is the condition to stop scan */
+			nr = READ_ONCE(sd_share->nr_idle_scan) + 1;
+			/* overloaded LLC is unlikely to have idle cpu/core */
+			if (nr == 1)
+				return -1;
+		}
+	}
+
+	for_each_cpu_wrap(cpu, cpus, target + 1) {
+		if (has_idle_core) {
+			i = select_idle_core(p, cpu, cpus, &idle_cpu);
+			if ((unsigned int)i < nr_cpumask_bits)
+				return i;
+
+		} else {
+			if (!--nr)
+				return -1;
+			idle_cpu = __select_idle_cpu(cpu, p);
+			if ((unsigned int)idle_cpu < nr_cpumask_bits)
+				break;
+		}
+	}
+
+	if (has_idle_core)
+		set_idle_cores(target, false);
+
+	if (sched_feat(SIS_PROP) && this_sd && !has_idle_core) {
+		time = cpu_clock(this) - time;
+
+		/*
+		 * Account for the scan cost of wakeups against the average
+		 * idle time.
+		 */
+		this_rq->wake_avg_idle -= min(this_rq->wake_avg_idle, time);
+
+		update_avg(&this_sd->avg_scan_cost, time);
+	}
+
+	return idle_cpu;
+}
+
+/*
+ * Scan the asym_capacity domain for idle CPUs; pick the first idle one on which
+ * the task fits. If no CPU is big enough, but there are idle ones, try to
+ * maximize capacity.
+ */
+static int
+select_idle_capacity(struct task_struct *p, struct sched_domain *sd, int target)
+{
+	unsigned long task_util, util_min, util_max, best_cap = 0;
+	int fits, best_fits = 0;
+	int cpu, best_cpu = -1;
+	struct cpumask *cpus;
+
+	cpus = this_cpu_cpumask_var_ptr(select_rq_mask);
+	cpumask_and(cpus, sched_domain_span(sd), p->cpus_ptr);
+
+	task_util = task_util_est(p);
+	util_min = uclamp_eff_value(p, UCLAMP_MIN);
+	util_max = uclamp_eff_value(p, UCLAMP_MAX);
+
+	for_each_cpu_wrap(cpu, cpus, target) {
+		unsigned long cpu_cap = capacity_of(cpu);
+
+		if (!available_idle_cpu(cpu) && !sched_idle_cpu(cpu))
+			continue;
+
+		fits = util_fits_cpu(task_util, util_min, util_max, cpu);
+
+		/* This CPU fits with all requirements */
+		if (fits > 0)
+			return cpu;
+		/*
+		 * Only the min performance hint (i.e. uclamp_min) doesn't fit.
+		 * Look for the CPU with best capacity.
+		 */
+		else if (fits < 0)
+			cpu_cap = capacity_orig_of(cpu) - thermal_load_avg(cpu_rq(cpu));
+
+		/*
+		 * First, select CPU which fits better (-1 being better than 0).
+		 * Then, select the one with best capacity at same level.
+		 */
+		if ((fits < best_fits) ||
+		    ((fits == best_fits) && (cpu_cap > best_cap))) {
+			best_cap = cpu_cap;
+			best_cpu = cpu;
+			best_fits = fits;
+		}
+	}
+
+	return best_cpu;
+}
+
+static inline bool asym_fits_cpu(unsigned long util,
+				 unsigned long util_min,
+				 unsigned long util_max,
+				 int cpu)
+{
+	if (sched_asym_cpucap_active())
+		/*
+		 * Return true only if the cpu fully fits the task requirements
+		 * which include the utilization and the performance hints.
+		 */
+		return (util_fits_cpu(util, util_min, util_max, cpu) > 0);
+
+	return true;
+}
+
+/*
+ * Try and locate an idle core/thread in the LLC cache domain.
+ */
+static int select_idle_sibling(struct task_struct *p, int prev, int target)
+{
+	bool has_idle_core = false;
+	struct sched_domain *sd;
+	unsigned long task_util, util_min, util_max;
+	int i, recent_used_cpu;
+
+	/*
+	 * On asymmetric system, update task utilization because we will check
+	 * that the task fits with cpu's capacity.
+	 */
+	if (sched_asym_cpucap_active()) {
+		sync_entity_load_avg(&p->se);
+		task_util = task_util_est(p);
+		util_min = uclamp_eff_value(p, UCLAMP_MIN);
+		util_max = uclamp_eff_value(p, UCLAMP_MAX);
+	}
+
+	/*
+	 * per-cpu select_rq_mask usage
+	 */
+	lockdep_assert_irqs_disabled();
+
+	if ((available_idle_cpu(target) || sched_idle_cpu(target)) &&
+	    asym_fits_cpu(task_util, util_min, util_max, target))
+		return target;
+
+	/*
+	 * If the previous CPU is cache affine and idle, don't be stupid:
+	 */
+	if (prev != target && cpus_share_cache(prev, target) &&
+	    (available_idle_cpu(prev) || sched_idle_cpu(prev)) &&
+	    asym_fits_cpu(task_util, util_min, util_max, prev))
+		return prev;
+
+	/*
+	 * Allow a per-cpu kthread to stack with the wakee if the
+	 * kworker thread and the tasks previous CPUs are the same.
+	 * The assumption is that the wakee queued work for the
+	 * per-cpu kthread that is now complete and the wakeup is
+	 * essentially a sync wakeup. An obvious example of this
+	 * pattern is IO completions.
+	 */
+	if (is_per_cpu_kthread(current) &&
+	    in_task() &&
+	    prev == smp_processor_id() &&
+	    this_rq()->nr_running <= 1 &&
+	    asym_fits_cpu(task_util, util_min, util_max, prev)) {
+		return prev;
+	}
+
+	/* Check a recently used CPU as a potential idle candidate: */
+	recent_used_cpu = p->recent_used_cpu;
+	p->recent_used_cpu = prev;
+	if (recent_used_cpu != prev &&
+	    recent_used_cpu != target &&
+	    cpus_share_cache(recent_used_cpu, target) &&
+	    (available_idle_cpu(recent_used_cpu) || sched_idle_cpu(recent_used_cpu)) &&
+	    cpumask_test_cpu(recent_used_cpu, p->cpus_ptr) &&
+	    asym_fits_cpu(task_util, util_min, util_max, recent_used_cpu)) {
+		return recent_used_cpu;
+	}
+
+	/*
+	 * For asymmetric CPU capacity systems, our domain of interest is
+	 * sd_asym_cpucapacity rather than sd_llc.
+	 */
+	if (sched_asym_cpucap_active()) {
+		sd = rcu_dereference(per_cpu(sd_asym_cpucapacity, target));
+		/*
+		 * On an asymmetric CPU capacity system where an exclusive
+		 * cpuset defines a symmetric island (i.e. one unique
+		 * capacity_orig value through the cpuset), the key will be set
+		 * but the CPUs within that cpuset will not have a domain with
+		 * SD_ASYM_CPUCAPACITY. These should follow the usual symmetric
+		 * capacity path.
+		 */
+		if (sd) {
+			i = select_idle_capacity(p, sd, target);
+			return ((unsigned)i < nr_cpumask_bits) ? i : target;
+		}
+	}
+
+	sd = rcu_dereference(per_cpu(sd_llc, target));
+	if (!sd)
+		return target;
+
+	if (sched_smt_active()) {
+		has_idle_core = test_idle_cores(target);
+
+		if (!has_idle_core && cpus_share_cache(prev, target)) {
+			i = select_idle_smt(p, prev);
+			if ((unsigned int)i < nr_cpumask_bits)
+				return i;
+		}
+	}
+
+	i = select_idle_cpu(p, sd, has_idle_core, target);
+	if ((unsigned)i < nr_cpumask_bits)
+		return i;
+
+	return target;
+}
+
+/**
+ * cpu_util() - Estimates the amount of CPU capacity used by CFS tasks.
+ * @cpu: the CPU to get the utilization for
+ * @p: task for which the CPU utilization should be predicted or NULL
+ * @dst_cpu: CPU @p migrates to, -1 if @p moves from @cpu or @p == NULL
+ * @boost: 1 to enable boosting, otherwise 0
+ *
+ * The unit of the return value must be the same as the one of CPU capacity
+ * so that CPU utilization can be compared with CPU capacity.
+ *
+ * CPU utilization is the sum of running time of runnable tasks plus the
+ * recent utilization of currently non-runnable tasks on that CPU.
+ * It represents the amount of CPU capacity currently used by CFS tasks in
+ * the range [0..max CPU capacity] with max CPU capacity being the CPU
+ * capacity at f_max.
+ *
+ * The estimated CPU utilization is defined as the maximum between CPU
+ * utilization and sum of the estimated utilization of the currently
+ * runnable tasks on that CPU. It preserves a utilization "snapshot" of
+ * previously-executed tasks, which helps better deduce how busy a CPU will
+ * be when a long-sleeping task wakes up. The contribution to CPU utilization
+ * of such a task would be significantly decayed at this point of time.
+ *
+ * Boosted CPU utilization is defined as max(CPU runnable, CPU utilization).
+ * CPU contention for CFS tasks can be detected by CPU runnable > CPU
+ * utilization. Boosting is implemented in cpu_util() so that internal
+ * users (e.g. EAS) can use it next to external users (e.g. schedutil),
+ * latter via cpu_util_cfs_boost().
+ *
+ * CPU utilization can be higher than the current CPU capacity
+ * (f_curr/f_max * max CPU capacity) or even the max CPU capacity because
+ * of rounding errors as well as task migrations or wakeups of new tasks.
+ * CPU utilization has to be capped to fit into the [0..max CPU capacity]
+ * range. Otherwise a group of CPUs (CPU0 util = 121% + CPU1 util = 80%)
+ * could be seen as over-utilized even though CPU1 has 20% of spare CPU
+ * capacity. CPU utilization is allowed to overshoot current CPU capacity
+ * though since this is useful for predicting the CPU capacity required
+ * after task migrations (scheduler-driven DVFS).
+ *
+ * Return: (Boosted) (estimated) utilization for the specified CPU.
+ */
+static unsigned long
+cpu_util(int cpu, struct task_struct *p, int dst_cpu, int boost)
+{
+	struct cfs_rq *cfs_rq = &cpu_rq(cpu)->cfs;
+	unsigned long util = READ_ONCE(cfs_rq->avg.util_avg);
+	unsigned long runnable;
+
+	if (boost) {
+		runnable = READ_ONCE(cfs_rq->avg.runnable_avg);
+		util = max(util, runnable);
+	}
+
+	/*
+	 * If @dst_cpu is -1 or @p migrates from @cpu to @dst_cpu remove its
+	 * contribution. If @p migrates from another CPU to @cpu add its
+	 * contribution. In all the other cases @cpu is not impacted by the
+	 * migration so its util_avg is already correct.
+	 */
+	if (p && task_cpu(p) == cpu && dst_cpu != cpu)
+		lsub_positive(&util, task_util(p));
+	else if (p && task_cpu(p) != cpu && dst_cpu == cpu)
+		util += task_util(p);
+
+	if (sched_feat(UTIL_EST)) {
+		unsigned long util_est;
+
+		util_est = READ_ONCE(cfs_rq->avg.util_est.enqueued);
+
+		/*
+		 * During wake-up @p isn't enqueued yet and doesn't contribute
+		 * to any cpu_rq(cpu)->cfs.avg.util_est.enqueued.
+		 * If @dst_cpu == @cpu add it to "simulate" cpu_util after @p
+		 * has been enqueued.
+		 *
+		 * During exec (@dst_cpu = -1) @p is enqueued and does
+		 * contribute to cpu_rq(cpu)->cfs.util_est.enqueued.
+		 * Remove it to "simulate" cpu_util without @p's contribution.
+		 *
+		 * Despite the task_on_rq_queued(@p) check there is still a
+		 * small window for a possible race when an exec
+		 * select_task_rq_fair() races with LB's detach_task().
+		 *
+		 *   detach_task()
+		 *     deactivate_task()
+		 *       p->on_rq = TASK_ON_RQ_MIGRATING;
+		 *       -------------------------------- A
+		 *       dequeue_task()                    \
+		 *         dequeue_task_fair()              + Race Time
+		 *           util_est_dequeue()            /
+		 *       -------------------------------- B
+		 *
+		 * The additional check "current == p" is required to further
+		 * reduce the race window.
+		 */
+		if (dst_cpu == cpu)
+			util_est += _task_util_est(p);
+		else if (p && unlikely(task_on_rq_queued(p) || current == p))
+			lsub_positive(&util_est, _task_util_est(p));
+
+		util = max(util, util_est);
+	}
+
+	return min(util, capacity_orig_of(cpu));
+}
+
+unsigned long cpu_util_cfs(int cpu)
+{
+	return cpu_util(cpu, NULL, -1, 0);
+}
+
+unsigned long cpu_util_cfs_boost(int cpu)
+{
+	return cpu_util(cpu, NULL, -1, 1);
+}
+
+/*
+ * cpu_util_without: compute cpu utilization without any contributions from *p
+ * @cpu: the CPU which utilization is requested
+ * @p: the task which utilization should be discounted
+ *
+ * The utilization of a CPU is defined by the utilization of tasks currently
+ * enqueued on that CPU as well as tasks which are currently sleeping after an
+ * execution on that CPU.
+ *
+ * This method returns the utilization of the specified CPU by discounting the
+ * utilization of the specified task, whenever the task is currently
+ * contributing to the CPU utilization.
+ */
+static unsigned long cpu_util_without(int cpu, struct task_struct *p)
+{
+	/* Task has no contribution or is new */
+	if (cpu != task_cpu(p) || !READ_ONCE(p->se.avg.last_update_time))
+		p = NULL;
+
+	return cpu_util(cpu, p, -1, 0);
+}
+
+/*
+ * energy_env - Utilization landscape for energy estimation.
+ * @task_busy_time: Utilization contribution by the task for which we test the
+ *                  placement. Given by eenv_task_busy_time().
+ * @pd_busy_time:   Utilization of the whole perf domain without the task
+ *                  contribution. Given by eenv_pd_busy_time().
+ * @cpu_cap:        Maximum CPU capacity for the perf domain.
+ * @pd_cap:         Entire perf domain capacity. (pd->nr_cpus * cpu_cap).
+ */
+struct energy_env {
+	unsigned long task_busy_time;
+	unsigned long pd_busy_time;
+	unsigned long cpu_cap;
+	unsigned long pd_cap;
+};
+
+/*
+ * Compute the task busy time for compute_energy(). This time cannot be
+ * injected directly into effective_cpu_util() because of the IRQ scaling.
+ * The latter only makes sense with the most recent CPUs where the task has
+ * run.
+ */
+static inline void eenv_task_busy_time(struct energy_env *eenv,
+				       struct task_struct *p, int prev_cpu)
+{
+	unsigned long busy_time, max_cap = arch_scale_cpu_capacity(prev_cpu);
+	unsigned long irq = cpu_util_irq(cpu_rq(prev_cpu));
+
+	if (unlikely(irq >= max_cap))
+		busy_time = max_cap;
+	else
+		busy_time = scale_irq_capacity(task_util_est(p), irq, max_cap);
+
+	eenv->task_busy_time = busy_time;
+}
+
+/*
+ * Compute the perf_domain (PD) busy time for compute_energy(). Based on the
+ * utilization for each @pd_cpus, it however doesn't take into account
+ * clamping since the ratio (utilization / cpu_capacity) is already enough to
+ * scale the EM reported power consumption at the (eventually clamped)
+ * cpu_capacity.
+ *
+ * The contribution of the task @p for which we want to estimate the
+ * energy cost is removed (by cpu_util()) and must be calculated
+ * separately (see eenv_task_busy_time). This ensures:
+ *
+ *   - A stable PD utilization, no matter which CPU of that PD we want to place
+ *     the task on.
+ *
+ *   - A fair comparison between CPUs as the task contribution (task_util())
+ *     will always be the same no matter which CPU utilization we rely on
+ *     (util_avg or util_est).
+ *
+ * Set @eenv busy time for the PD that spans @pd_cpus. This busy time can't
+ * exceed @eenv->pd_cap.
+ */
+static inline void eenv_pd_busy_time(struct energy_env *eenv,
+				     struct cpumask *pd_cpus,
+				     struct task_struct *p)
+{
+	unsigned long busy_time = 0;
+	int cpu;
+
+	for_each_cpu(cpu, pd_cpus) {
+		unsigned long util = cpu_util(cpu, p, -1, 0);
+
+		busy_time += effective_cpu_util(cpu, util, ENERGY_UTIL, NULL);
+	}
+
+	eenv->pd_busy_time = min(eenv->pd_cap, busy_time);
+}
+
+/*
+ * Compute the maximum utilization for compute_energy() when the task @p
+ * is placed on the cpu @dst_cpu.
+ *
+ * Returns the maximum utilization among @eenv->cpus. This utilization can't
+ * exceed @eenv->cpu_cap.
+ */
+static inline unsigned long
+eenv_pd_max_util(struct energy_env *eenv, struct cpumask *pd_cpus,
+		 struct task_struct *p, int dst_cpu)
+{
+	unsigned long max_util = 0;
+	int cpu;
+
+	for_each_cpu(cpu, pd_cpus) {
+		struct task_struct *tsk = (cpu == dst_cpu) ? p : NULL;
+		unsigned long util = cpu_util(cpu, p, dst_cpu, 1);
+		unsigned long eff_util;
+
+		/*
+		 * Performance domain frequency: utilization clamping
+		 * must be considered since it affects the selection
+		 * of the performance domain frequency.
+		 * NOTE: in case RT tasks are running, by default the
+		 * FREQUENCY_UTIL's utilization can be max OPP.
+		 */
+		eff_util = effective_cpu_util(cpu, util, FREQUENCY_UTIL, tsk);
+		max_util = max(max_util, eff_util);
+	}
+
+	return min(max_util, eenv->cpu_cap);
+}
+
+/*
+ * compute_energy(): Use the Energy Model to estimate the energy that @pd would
+ * consume for a given utilization landscape @eenv. When @dst_cpu < 0, the task
+ * contribution is ignored.
+ */
+static inline unsigned long
+compute_energy(struct energy_env *eenv, struct perf_domain *pd,
+	       struct cpumask *pd_cpus, struct task_struct *p, int dst_cpu)
+{
+	unsigned long max_util = eenv_pd_max_util(eenv, pd_cpus, p, dst_cpu);
+	unsigned long busy_time = eenv->pd_busy_time;
+
+	if (dst_cpu >= 0)
+		busy_time = min(eenv->pd_cap, busy_time + eenv->task_busy_time);
+
+	return em_cpu_energy(pd->em_pd, max_util, busy_time, eenv->cpu_cap);
+}
+
+/*
+ * find_energy_efficient_cpu(): Find most energy-efficient target CPU for the
+ * waking task. find_energy_efficient_cpu() looks for the CPU with maximum
+ * spare capacity in each performance domain and uses it as a potential
+ * candidate to execute the task. Then, it uses the Energy Model to figure
+ * out which of the CPU candidates is the most energy-efficient.
+ *
+ * The rationale for this heuristic is as follows. In a performance domain,
+ * all the most energy efficient CPU candidates (according to the Energy
+ * Model) are those for which we'll request a low frequency. When there are
+ * several CPUs for which the frequency request will be the same, we don't
+ * have enough data to break the tie between them, because the Energy Model
+ * only includes active power costs. With this model, if we assume that
+ * frequency requests follow utilization (e.g. using schedutil), the CPU with
+ * the maximum spare capacity in a performance domain is guaranteed to be among
+ * the best candidates of the performance domain.
+ *
+ * In practice, it could be preferable from an energy standpoint to pack
+ * small tasks on a CPU in order to let other CPUs go in deeper idle states,
+ * but that could also hurt our chances to go cluster idle, and we have no
+ * ways to tell with the current Energy Model if this is actually a good
+ * idea or not. So, find_energy_efficient_cpu() basically favors
+ * cluster-packing, and spreading inside a cluster. That should at least be
+ * a good thing for latency, and this is consistent with the idea that most
+ * of the energy savings of EAS come from the asymmetry of the system, and
+ * not so much from breaking the tie between identical CPUs. That's also the
+ * reason why EAS is enabled in the topology code only for systems where
+ * SD_ASYM_CPUCAPACITY is set.
+ *
+ * NOTE: Forkees are not accepted in the energy-aware wake-up path because
+ * they don't have any useful utilization data yet and it's not possible to
+ * forecast their impact on energy consumption. Consequently, they will be
+ * placed by find_idlest_cpu() on the least loaded CPU, which might turn out
+ * to be energy-inefficient in some use-cases. The alternative would be to
+ * bias new tasks towards specific types of CPUs first, or to try to infer
+ * their util_avg from the parent task, but those heuristics could hurt
+ * other use-cases too. So, until someone finds a better way to solve this,
+ * let's keep things simple by re-using the existing slow path.
+ */
+static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu)
+{
+	struct cpumask *cpus = this_cpu_cpumask_var_ptr(select_rq_mask);
+	unsigned long prev_delta = ULONG_MAX, best_delta = ULONG_MAX;
+	unsigned long p_util_min = uclamp_is_used() ? uclamp_eff_value(p, UCLAMP_MIN) : 0;
+	unsigned long p_util_max = uclamp_is_used() ? uclamp_eff_value(p, UCLAMP_MAX) : 1024;
+	struct root_domain *rd = this_rq()->rd;
+	int cpu, best_energy_cpu, target = -1;
+	int prev_fits = -1, best_fits = -1;
+	unsigned long best_thermal_cap = 0;
+	unsigned long prev_thermal_cap = 0;
+	struct sched_domain *sd;
+	struct perf_domain *pd;
+	struct energy_env eenv;
+
+	rcu_read_lock();
+	pd = rcu_dereference(rd->pd);
+	if (!pd || READ_ONCE(rd->overutilized))
+		goto unlock;
+
+	/*
+	 * Energy-aware wake-up happens on the lowest sched_domain starting
+	 * from sd_asym_cpucapacity spanning over this_cpu and prev_cpu.
+	 */
+	sd = rcu_dereference(*this_cpu_ptr(&sd_asym_cpucapacity));
+	while (sd && !cpumask_test_cpu(prev_cpu, sched_domain_span(sd)))
+		sd = sd->parent;
+	if (!sd)
+		goto unlock;
+
+	target = prev_cpu;
+
+	sync_entity_load_avg(&p->se);
+	if (!task_util_est(p) && p_util_min == 0)
+		goto unlock;
+
+	eenv_task_busy_time(&eenv, p, prev_cpu);
+
+	for (; pd; pd = pd->next) {
+		unsigned long util_min = p_util_min, util_max = p_util_max;
+		unsigned long cpu_cap, cpu_thermal_cap, util;
+		long prev_spare_cap = -1, max_spare_cap = -1;
+		unsigned long rq_util_min, rq_util_max;
+		unsigned long cur_delta, base_energy;
+		int max_spare_cap_cpu = -1;
+		int fits, max_fits = -1;
+
+		cpumask_and(cpus, perf_domain_span(pd), cpu_online_mask);
+
+		if (cpumask_empty(cpus))
+			continue;
+
+		/* Account thermal pressure for the energy estimation */
+		cpu = cpumask_first(cpus);
+		cpu_thermal_cap = arch_scale_cpu_capacity(cpu);
+		cpu_thermal_cap -= arch_scale_thermal_pressure(cpu);
+
+		eenv.cpu_cap = cpu_thermal_cap;
+		eenv.pd_cap = 0;
+
+		for_each_cpu(cpu, cpus) {
+			struct rq *rq = cpu_rq(cpu);
+
+			eenv.pd_cap += cpu_thermal_cap;
+
+			if (!cpumask_test_cpu(cpu, sched_domain_span(sd)))
+				continue;
+
+			if (!cpumask_test_cpu(cpu, p->cpus_ptr))
+				continue;
+
+			util = cpu_util(cpu, p, cpu, 0);
+			cpu_cap = capacity_of(cpu);
+
+			/*
+			 * Skip CPUs that cannot satisfy the capacity request.
+			 * IOW, placing the task there would make the CPU
+			 * overutilized. Take uclamp into account to see how
+			 * much capacity we can get out of the CPU; this is
+			 * aligned with sched_cpu_util().
+			 */
+			if (uclamp_is_used() && !uclamp_rq_is_idle(rq)) {
+				/*
+				 * Open code uclamp_rq_util_with() except for
+				 * the clamp() part. Ie: apply max aggregation
+				 * only. util_fits_cpu() logic requires to
+				 * operate on non clamped util but must use the
+				 * max-aggregated uclamp_{min, max}.
+				 */
+				rq_util_min = uclamp_rq_get(rq, UCLAMP_MIN);
+				rq_util_max = uclamp_rq_get(rq, UCLAMP_MAX);
+
+				util_min = max(rq_util_min, p_util_min);
+				util_max = max(rq_util_max, p_util_max);
+			}
+
+			fits = util_fits_cpu(util, util_min, util_max, cpu);
+			if (!fits)
+				continue;
+
+			lsub_positive(&cpu_cap, util);
+
+			if (cpu == prev_cpu) {
+				/* Always use prev_cpu as a candidate. */
+				prev_spare_cap = cpu_cap;
+				prev_fits = fits;
+			} else if ((fits > max_fits) ||
+				   ((fits == max_fits) && ((long)cpu_cap > max_spare_cap))) {
+				/*
+				 * Find the CPU with the maximum spare capacity
+				 * among the remaining CPUs in the performance
+				 * domain.
+				 */
+				max_spare_cap = cpu_cap;
+				max_spare_cap_cpu = cpu;
+				max_fits = fits;
+			}
+		}
+
+		if (max_spare_cap_cpu < 0 && prev_spare_cap < 0)
+			continue;
+
+		eenv_pd_busy_time(&eenv, cpus, p);
+		/* Compute the 'base' energy of the pd, without @p */
+		base_energy = compute_energy(&eenv, pd, cpus, p, -1);
+
+		/* Evaluate the energy impact of using prev_cpu. */
+		if (prev_spare_cap > -1) {
+			prev_delta = compute_energy(&eenv, pd, cpus, p,
+						    prev_cpu);
+			/* CPU utilization has changed */
+			if (prev_delta < base_energy)
+				goto unlock;
+			prev_delta -= base_energy;
+			prev_thermal_cap = cpu_thermal_cap;
+			best_delta = min(best_delta, prev_delta);
+		}
+
+		/* Evaluate the energy impact of using max_spare_cap_cpu. */
+		if (max_spare_cap_cpu >= 0 && max_spare_cap > prev_spare_cap) {
+			/* Current best energy cpu fits better */
+			if (max_fits < best_fits)
+				continue;
+
+			/*
+			 * Both don't fit performance hint (i.e. uclamp_min)
+			 * but best energy cpu has better capacity.
+			 */
+			if ((max_fits < 0) &&
+			    (cpu_thermal_cap <= best_thermal_cap))
+				continue;
+
+			cur_delta = compute_energy(&eenv, pd, cpus, p,
+						   max_spare_cap_cpu);
+			/* CPU utilization has changed */
+			if (cur_delta < base_energy)
+				goto unlock;
+			cur_delta -= base_energy;
+
+			/*
+			 * Both fit for the task but best energy cpu has lower
+			 * energy impact.
+			 */
+			if ((max_fits > 0) && (best_fits > 0) &&
+			    (cur_delta >= best_delta))
+				continue;
+
+			best_delta = cur_delta;
+			best_energy_cpu = max_spare_cap_cpu;
+			best_fits = max_fits;
+			best_thermal_cap = cpu_thermal_cap;
+		}
+	}
+	rcu_read_unlock();
+
+	if ((best_fits > prev_fits) ||
+	    ((best_fits > 0) && (best_delta < prev_delta)) ||
+	    ((best_fits < 0) && (best_thermal_cap > prev_thermal_cap)))
+		target = best_energy_cpu;
+
+	return target;
+
+unlock:
+	rcu_read_unlock();
+
+	return target;
+}
+
+/*
+ * select_task_rq_fair: Select target runqueue for the waking task in domains
+ * that have the relevant SD flag set. In practice, this is SD_BALANCE_WAKE,
+ * SD_BALANCE_FORK, or SD_BALANCE_EXEC.
+ *
+ * Balances load by selecting the idlest CPU in the idlest group, or under
+ * certain conditions an idle sibling CPU if the domain has SD_WAKE_AFFINE set.
+ *
+ * Returns the target CPU number.
+ */
+static int
+select_task_rq_fair(struct task_struct *p, int prev_cpu, int wake_flags)
+{
+	int sync = (wake_flags & WF_SYNC) && !(current->flags & PF_EXITING);
+	struct sched_domain *tmp, *sd = NULL;
+	int cpu = smp_processor_id();
+	int new_cpu = prev_cpu;
+	int want_affine = 0;
+	/* SD_flags and WF_flags share the first nibble */
+	int sd_flag = wake_flags & 0xF;
+
+	/*
+	 * required for stable ->cpus_allowed
+	 */
+	lockdep_assert_held(&p->pi_lock);
+	if (wake_flags & WF_TTWU) {
+		record_wakee(p);
+
+		if ((wake_flags & WF_CURRENT_CPU) &&
+		    cpumask_test_cpu(cpu, p->cpus_ptr))
+			return cpu;
+
+		if (sched_energy_enabled()) {
+			new_cpu = find_energy_efficient_cpu(p, prev_cpu);
+			if (new_cpu >= 0)
+				return new_cpu;
+			new_cpu = prev_cpu;
+		}
+
+		want_affine = !wake_wide(p) && cpumask_test_cpu(cpu, p->cpus_ptr);
+	}
+
+	rcu_read_lock();
+	for_each_domain(cpu, tmp) {
+		/*
+		 * If both 'cpu' and 'prev_cpu' are part of this domain,
+		 * cpu is a valid SD_WAKE_AFFINE target.
+		 */
+		if (want_affine && (tmp->flags & SD_WAKE_AFFINE) &&
+		    cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) {
+			if (cpu != prev_cpu)
+				new_cpu = wake_affine(tmp, p, cpu, prev_cpu, sync);
+
+			sd = NULL; /* Prefer wake_affine over balance flags */
+			break;
+		}
+
+		/*
+		 * Usually only true for WF_EXEC and WF_FORK, as sched_domains
+		 * usually do not have SD_BALANCE_WAKE set. That means wakeup
+		 * will usually go to the fast path.
+		 */
+		if (tmp->flags & sd_flag)
+			sd = tmp;
+		else if (!want_affine)
+			break;
+	}
+
+	if (unlikely(sd)) {
+		/* Slow path */
+		new_cpu = find_idlest_cpu(sd, p, cpu, prev_cpu, sd_flag);
+	} else if (wake_flags & WF_TTWU) { /* XXX always ? */
+		/* Fast path */
+		new_cpu = select_idle_sibling(p, prev_cpu, new_cpu);
+	}
+	rcu_read_unlock();
+
+	return new_cpu;
+}
+
+/*
+ * Called immediately before a task is migrated to a new CPU; task_cpu(p) and
+ * cfs_rq_of(p) references at time of call are still valid and identify the
+ * previous CPU. The caller guarantees p->pi_lock or task_rq(p)->lock is held.
+ */
+static void migrate_task_rq_fair(struct task_struct *p, int new_cpu)
+{
+	struct sched_entity *se = &p->se;
+
+	if (!task_on_rq_migrating(p)) {
+		remove_entity_load_avg(se);
+
+		/*
+		 * Here, the task's PELT values have been updated according to
+		 * the current rq's clock. But if that clock hasn't been
+		 * updated in a while, a substantial idle time will be missed,
+		 * leading to an inflation after wake-up on the new rq.
+		 *
+		 * Estimate the missing time from the cfs_rq last_update_time
+		 * and update sched_avg to improve the PELT continuity after
+		 * migration.
+		 */
+		migrate_se_pelt_lag(se);
+	}
+
+	/* Tell new CPU we are migrated */
+	se->avg.last_update_time = 0;
+
+	update_scan_period(p, new_cpu);
+}
+
+static void task_dead_fair(struct task_struct *p)
+{
+	remove_entity_load_avg(&p->se);
+}
+
+static int
+balance_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
+{
+	if (rq->nr_running)
+		return 1;
+
+	return newidle_balance(rq, rf) != 0;
+}
+#endif /* CONFIG_SMP */
+
+static void set_next_buddy(struct sched_entity *se)
+{
+	for_each_sched_entity(se) {
+		if (SCHED_WARN_ON(!se->on_rq))
+			return;
+		if (se_is_idle(se))
+			return;
+		cfs_rq_of(se)->next = se;
+	}
+}
+
+/*
+ * Preempt the current task with a newly woken task if needed:
+ */
+static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_flags)
+{
+	struct task_struct *curr = rq->curr;
+	struct sched_entity *se = &curr->se, *pse = &p->se;
+	struct cfs_rq *cfs_rq = task_cfs_rq(curr);
+	int next_buddy_marked = 0;
+	int cse_is_idle, pse_is_idle;
+
+	if (unlikely(se == pse))
+		return;
+
+	/*
+	 * This is possible from callers such as attach_tasks(), in which we
+	 * unconditionally check_preempt_curr() after an enqueue (which may have
+	 * lead to a throttle).  This both saves work and prevents false
+	 * next-buddy nomination below.
+	 */
+	if (unlikely(throttled_hierarchy(cfs_rq_of(pse))))
+		return;
+
+	if (sched_feat(NEXT_BUDDY) && !(wake_flags & WF_FORK)) {
+		set_next_buddy(pse);
+		next_buddy_marked = 1;
+	}
+
+	/*
+	 * We can come here with TIF_NEED_RESCHED already set from new task
+	 * wake up path.
+	 *
+	 * Note: this also catches the edge-case of curr being in a throttled
+	 * group (e.g. via set_curr_task), since update_curr() (in the
+	 * enqueue of curr) will have resulted in resched being set.  This
+	 * prevents us from potentially nominating it as a false LAST_BUDDY
+	 * below.
+	 */
+	if (test_tsk_need_resched(curr))
+		return;
+
+	/* Idle tasks are by definition preempted by non-idle tasks. */
+	if (unlikely(task_has_idle_policy(curr)) &&
+	    likely(!task_has_idle_policy(p)))
+		goto preempt;
+
+	/*
+	 * Batch and idle tasks do not preempt non-idle tasks (their preemption
+	 * is driven by the tick):
+	 */
+	if (unlikely(p->policy != SCHED_NORMAL) || !sched_feat(WAKEUP_PREEMPTION))
+		return;
+
+	find_matching_se(&se, &pse);
+	WARN_ON_ONCE(!pse);
+
+	cse_is_idle = se_is_idle(se);
+	pse_is_idle = se_is_idle(pse);
+
+	/*
+	 * Preempt an idle group in favor of a non-idle group (and don't preempt
+	 * in the inverse case).
+	 */
+	if (cse_is_idle && !pse_is_idle)
+		goto preempt;
+	if (cse_is_idle != pse_is_idle)
+		return;
+
+	cfs_rq = cfs_rq_of(se);
+	update_curr(cfs_rq);
+
+	/*
+	 * XXX pick_eevdf(cfs_rq) != se ?
+	 */
+	if (pick_eevdf(cfs_rq) == pse)
+		goto preempt;
+
+	return;
+
+preempt:
+	resched_curr(rq);
+}
+
+#ifdef CONFIG_SMP
+static struct task_struct *pick_task_fair(struct rq *rq)
+{
+	struct sched_entity *se;
+	struct cfs_rq *cfs_rq;
+
+again:
+	cfs_rq = &rq->cfs;
+	if (!cfs_rq->nr_running)
+		return NULL;
+
+	do {
+		struct sched_entity *curr = cfs_rq->curr;
+
+		/* When we pick for a remote RQ, we'll not have done put_prev_entity() */
+		if (curr) {
+			if (curr->on_rq)
+				update_curr(cfs_rq);
+			else
+				curr = NULL;
+
+			if (unlikely(check_cfs_rq_runtime(cfs_rq)))
+				goto again;
+		}
+
+		se = pick_next_entity(cfs_rq, curr);
+		cfs_rq = group_cfs_rq(se);
+	} while (cfs_rq);
+
+	return task_of(se);
+}
+#endif
+
+struct task_struct *
+pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
+{
+	struct cfs_rq *cfs_rq = &rq->cfs;
+	struct sched_entity *se;
+	struct task_struct *p;
+	int new_tasks;
+
+again:
+	if (!sched_fair_runnable(rq))
+		goto idle;
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	if (!prev || prev->sched_class != &fair_sched_class)
+		goto simple;
+
+	/*
+	 * Because of the set_next_buddy() in dequeue_task_fair() it is rather
+	 * likely that a next task is from the same cgroup as the current.
+	 *
+	 * Therefore attempt to avoid putting and setting the entire cgroup
+	 * hierarchy, only change the part that actually changes.
+	 */
+
+	do {
+		struct sched_entity *curr = cfs_rq->curr;
+
+		/*
+		 * Since we got here without doing put_prev_entity() we also
+		 * have to consider cfs_rq->curr. If it is still a runnable
+		 * entity, update_curr() will update its vruntime, otherwise
+		 * forget we've ever seen it.
+		 */
+		if (curr) {
+			if (curr->on_rq)
+				update_curr(cfs_rq);
+			else
+				curr = NULL;
+
+			/*
+			 * This call to check_cfs_rq_runtime() will do the
+			 * throttle and dequeue its entity in the parent(s).
+			 * Therefore the nr_running test will indeed
+			 * be correct.
+			 */
+			if (unlikely(check_cfs_rq_runtime(cfs_rq))) {
+				cfs_rq = &rq->cfs;
+
+				if (!cfs_rq->nr_running)
+					goto idle;
+
+				goto simple;
+			}
+		}
+
+		se = pick_next_entity(cfs_rq, curr);
+		cfs_rq = group_cfs_rq(se);
+	} while (cfs_rq);
+
+	p = task_of(se);
+
+	/*
+	 * Since we haven't yet done put_prev_entity and if the selected task
+	 * is a different task than we started out with, try and touch the
+	 * least amount of cfs_rqs.
+	 */
+	if (prev != p) {
+		struct sched_entity *pse = &prev->se;
+
+		while (!(cfs_rq = is_same_group(se, pse))) {
+			int se_depth = se->depth;
+			int pse_depth = pse->depth;
+
+			if (se_depth <= pse_depth) {
+				put_prev_entity(cfs_rq_of(pse), pse);
+				pse = parent_entity(pse);
+			}
+			if (se_depth >= pse_depth) {
+				set_next_entity(cfs_rq_of(se), se);
+				se = parent_entity(se);
+			}
+		}
+
+		put_prev_entity(cfs_rq, pse);
+		set_next_entity(cfs_rq, se);
+	}
+
+	goto done;
+simple:
+#endif
+	if (prev)
+		put_prev_task(rq, prev);
+
+	do {
+		se = pick_next_entity(cfs_rq, NULL);
+		set_next_entity(cfs_rq, se);
+		cfs_rq = group_cfs_rq(se);
+	} while (cfs_rq);
+
+	p = task_of(se);
+
+done: __maybe_unused;
+#ifdef CONFIG_SMP
+	/*
+	 * Move the next running task to the front of
+	 * the list, so our cfs_tasks list becomes MRU
+	 * one.
+	 */
+	list_move(&p->se.group_node, &rq->cfs_tasks);
+#endif
+
+	if (hrtick_enabled_fair(rq))
+		hrtick_start_fair(rq, p);
+
+	update_misfit_status(p, rq);
+	sched_fair_update_stop_tick(rq, p);
+
+	return p;
+
+idle:
+	if (!rf)
+		return NULL;
+
+	new_tasks = newidle_balance(rq, rf);
+
+	/*
+	 * Because newidle_balance() releases (and re-acquires) rq->lock, it is
+	 * possible for any higher priority task to appear. In that case we
+	 * must re-start the pick_next_entity() loop.
+	 */
+	if (new_tasks < 0)
+		return RETRY_TASK;
+
+	if (new_tasks > 0)
+		goto again;
+
+	/*
+	 * rq is about to be idle, check if we need to update the
+	 * lost_idle_time of clock_pelt
+	 */
+	update_idle_rq_clock_pelt(rq);
+
+	return NULL;
+}
+
+static struct task_struct *__pick_next_task_fair(struct rq *rq)
+{
+	return pick_next_task_fair(rq, NULL, NULL);
+}
+
+/*
+ * Account for a descheduled task:
+ */
+static void put_prev_task_fair(struct rq *rq, struct task_struct *prev)
+{
+	struct sched_entity *se = &prev->se;
+	struct cfs_rq *cfs_rq;
+
+	for_each_sched_entity(se) {
+		cfs_rq = cfs_rq_of(se);
+		put_prev_entity(cfs_rq, se);
+	}
+}
+
+/*
+ * sched_yield() is very simple
+ */
+static void yield_task_fair(struct rq *rq)
+{
+	struct task_struct *curr = rq->curr;
+	struct cfs_rq *cfs_rq = task_cfs_rq(curr);
+	struct sched_entity *se = &curr->se;
+
+	/*
+	 * Are we the only task in the tree?
+	 */
+	if (unlikely(rq->nr_running == 1))
+		return;
+
+	clear_buddies(cfs_rq, se);
+
+	update_rq_clock(rq);
+	/*
+	 * Update run-time statistics of the 'current'.
+	 */
+	update_curr(cfs_rq);
+	/*
+	 * Tell update_rq_clock() that we've just updated,
+	 * so we don't do microscopic update in schedule()
+	 * and double the fastpath cost.
+	 */
+	rq_clock_skip_update(rq);
+
+	se->deadline += calc_delta_fair(se->slice, se);
+}
+
+static bool yield_to_task_fair(struct rq *rq, struct task_struct *p)
+{
+	struct sched_entity *se = &p->se;
+
+	/* throttled hierarchies are not runnable */
+	if (!se->on_rq || throttled_hierarchy(cfs_rq_of(se)))
+		return false;
+
+	/* Tell the scheduler that we'd really like pse to run next. */
+	set_next_buddy(se);
+
+	yield_task_fair(rq);
+
+	return true;
+}
+
+#ifdef CONFIG_SMP
+/**************************************************
+ * Fair scheduling class load-balancing methods.
+ *
+ * BASICS
+ *
+ * The purpose of load-balancing is to achieve the same basic fairness the
+ * per-CPU scheduler provides, namely provide a proportional amount of compute
+ * time to each task. This is expressed in the following equation:
+ *
+ *   W_i,n/P_i == W_j,n/P_j for all i,j                               (1)
+ *
+ * Where W_i,n is the n-th weight average for CPU i. The instantaneous weight
+ * W_i,0 is defined as:
+ *
+ *   W_i,0 = \Sum_j w_i,j                                             (2)
+ *
+ * Where w_i,j is the weight of the j-th runnable task on CPU i. This weight
+ * is derived from the nice value as per sched_prio_to_weight[].
+ *
+ * The weight average is an exponential decay average of the instantaneous
+ * weight:
+ *
+ *   W'_i,n = (2^n - 1) / 2^n * W_i,n + 1 / 2^n * W_i,0               (3)
+ *
+ * C_i is the compute capacity of CPU i, typically it is the
+ * fraction of 'recent' time available for SCHED_OTHER task execution. But it
+ * can also include other factors [XXX].
+ *
+ * To achieve this balance we define a measure of imbalance which follows
+ * directly from (1):
+ *
+ *   imb_i,j = max{ avg(W/C), W_i/C_i } - min{ avg(W/C), W_j/C_j }    (4)
+ *
+ * We them move tasks around to minimize the imbalance. In the continuous
+ * function space it is obvious this converges, in the discrete case we get
+ * a few fun cases generally called infeasible weight scenarios.
+ *
+ * [XXX expand on:
+ *     - infeasible weights;
+ *     - local vs global optima in the discrete case. ]
+ *
+ *
+ * SCHED DOMAINS
+ *
+ * In order to solve the imbalance equation (4), and avoid the obvious O(n^2)
+ * for all i,j solution, we create a tree of CPUs that follows the hardware
+ * topology where each level pairs two lower groups (or better). This results
+ * in O(log n) layers. Furthermore we reduce the number of CPUs going up the
+ * tree to only the first of the previous level and we decrease the frequency
+ * of load-balance at each level inv. proportional to the number of CPUs in
+ * the groups.
+ *
+ * This yields:
+ *
+ *     log_2 n     1     n
+ *   \Sum       { --- * --- * 2^i } = O(n)                            (5)
+ *     i = 0      2^i   2^i
+ *                               `- size of each group
+ *         |         |     `- number of CPUs doing load-balance
+ *         |         `- freq
+ *         `- sum over all levels
+ *
+ * Coupled with a limit on how many tasks we can migrate every balance pass,
+ * this makes (5) the runtime complexity of the balancer.
+ *
+ * An important property here is that each CPU is still (indirectly) connected
+ * to every other CPU in at most O(log n) steps:
+ *
+ * The adjacency matrix of the resulting graph is given by:
+ *
+ *             log_2 n
+ *   A_i,j = \Union     (i % 2^k == 0) && i / 2^(k+1) == j / 2^(k+1)  (6)
+ *             k = 0
+ *
+ * And you'll find that:
+ *
+ *   A^(log_2 n)_i,j != 0  for all i,j                                (7)
+ *
+ * Showing there's indeed a path between every CPU in at most O(log n) steps.
+ * The task movement gives a factor of O(m), giving a convergence complexity
+ * of:
+ *
+ *   O(nm log n),  n := nr_cpus, m := nr_tasks                        (8)
+ *
+ *
+ * WORK CONSERVING
+ *
+ * In order to avoid CPUs going idle while there's still work to do, new idle
+ * balancing is more aggressive and has the newly idle CPU iterate up the domain
+ * tree itself instead of relying on other CPUs to bring it work.
+ *
+ * This adds some complexity to both (5) and (8) but it reduces the total idle
+ * time.
+ *
+ * [XXX more?]
+ *
+ *
+ * CGROUPS
+ *
+ * Cgroups make a horror show out of (2), instead of a simple sum we get:
+ *
+ *                                s_k,i
+ *   W_i,0 = \Sum_j \Prod_k w_k * -----                               (9)
+ *                                 S_k
+ *
+ * Where
+ *
+ *   s_k,i = \Sum_j w_i,j,k  and  S_k = \Sum_i s_k,i                 (10)
+ *
+ * w_i,j,k is the weight of the j-th runnable task in the k-th cgroup on CPU i.
+ *
+ * The big problem is S_k, its a global sum needed to compute a local (W_i)
+ * property.
+ *
+ * [XXX write more on how we solve this.. _after_ merging pjt's patches that
+ *      rewrite all of this once again.]
+ */
+
+static unsigned long __read_mostly max_load_balance_interval = HZ/10;
+
+enum fbq_type { regular, remote, all };
+
+/*
+ * 'group_type' describes the group of CPUs at the moment of load balancing.
+ *
+ * The enum is ordered by pulling priority, with the group with lowest priority
+ * first so the group_type can simply be compared when selecting the busiest
+ * group. See update_sd_pick_busiest().
+ */
+enum group_type {
+	/* The group has spare capacity that can be used to run more tasks.  */
+	group_has_spare = 0,
+	/*
+	 * The group is fully used and the tasks don't compete for more CPU
+	 * cycles. Nevertheless, some tasks might wait before running.
+	 */
+	group_fully_busy,
+	/*
+	 * One task doesn't fit with CPU's capacity and must be migrated to a
+	 * more powerful CPU.
+	 */
+	group_misfit_task,
+	/*
+	 * Balance SMT group that's fully busy. Can benefit from migration
+	 * a task on SMT with busy sibling to another CPU on idle core.
+	 */
+	group_smt_balance,
+	/*
+	 * SD_ASYM_PACKING only: One local CPU with higher capacity is available,
+	 * and the task should be migrated to it instead of running on the
+	 * current CPU.
+	 */
+	group_asym_packing,
+	/*
+	 * The tasks' affinity constraints previously prevented the scheduler
+	 * from balancing the load across the system.
+	 */
+	group_imbalanced,
+	/*
+	 * The CPU is overloaded and can't provide expected CPU cycles to all
+	 * tasks.
+	 */
+	group_overloaded
+};
+
+enum migration_type {
+	migrate_load = 0,
+	migrate_util,
+	migrate_task,
+	migrate_misfit
+};
+
+#define LBF_ALL_PINNED	0x01
+#define LBF_NEED_BREAK	0x02
+#define LBF_DST_PINNED  0x04
+#define LBF_SOME_PINNED	0x08
+#define LBF_ACTIVE_LB	0x10
+
+struct lb_env {
+	struct sched_domain	*sd;
+
+	struct rq		*src_rq;
+	int			src_cpu;
+
+	int			dst_cpu;
+	struct rq		*dst_rq;
+
+	struct cpumask		*dst_grpmask;
+	int			new_dst_cpu;
+	enum cpu_idle_type	idle;
+	long			imbalance;
+	/* The set of CPUs under consideration for load-balancing */
+	struct cpumask		*cpus;
+
+	unsigned int		flags;
+
+	unsigned int		loop;
+	unsigned int		loop_break;
+	unsigned int		loop_max;
+
+	enum fbq_type		fbq_type;
+	enum migration_type	migration_type;
+	struct list_head	tasks;
+};
+
+/*
+ * Is this task likely cache-hot:
+ */
+static int task_hot(struct task_struct *p, struct lb_env *env)
+{
+	s64 delta;
+
+	lockdep_assert_rq_held(env->src_rq);
+
+	if (p->sched_class != &fair_sched_class)
+		return 0;
+
+	if (unlikely(task_has_idle_policy(p)))
+		return 0;
+
+	/* SMT siblings share cache */
+	if (env->sd->flags & SD_SHARE_CPUCAPACITY)
+		return 0;
+
+	/*
+	 * Buddy candidates are cache hot:
+	 */
+	if (sched_feat(CACHE_HOT_BUDDY) && env->dst_rq->nr_running &&
+	    (&p->se == cfs_rq_of(&p->se)->next))
+		return 1;
+
+	if (sysctl_sched_migration_cost == -1)
+		return 1;
+
+	/*
+	 * Don't migrate task if the task's cookie does not match
+	 * with the destination CPU's core cookie.
+	 */
+	if (!sched_core_cookie_match(cpu_rq(env->dst_cpu), p))
+		return 1;
+
+	if (sysctl_sched_migration_cost == 0)
+		return 0;
+
+	delta = rq_clock_task(env->src_rq) - p->se.exec_start;
+
+	return delta < (s64)sysctl_sched_migration_cost;
+}
+
+#ifdef CONFIG_NUMA_BALANCING
+/*
+ * Returns 1, if task migration degrades locality
+ * Returns 0, if task migration improves locality i.e migration preferred.
+ * Returns -1, if task migration is not affected by locality.
+ */
+static int migrate_degrades_locality(struct task_struct *p, struct lb_env *env)
+{
+	struct numa_group *numa_group = rcu_dereference(p->numa_group);
+	unsigned long src_weight, dst_weight;
+	int src_nid, dst_nid, dist;
+
+	if (!static_branch_likely(&sched_numa_balancing))
+		return -1;
+
+	if (!p->numa_faults || !(env->sd->flags & SD_NUMA))
+		return -1;
+
+	src_nid = cpu_to_node(env->src_cpu);
+	dst_nid = cpu_to_node(env->dst_cpu);
+
+	if (src_nid == dst_nid)
+		return -1;
+
+	/* Migrating away from the preferred node is always bad. */
+	if (src_nid == p->numa_preferred_nid) {
+		if (env->src_rq->nr_running > env->src_rq->nr_preferred_running)
+			return 1;
+		else
+			return -1;
+	}
+
+	/* Encourage migration to the preferred node. */
+	if (dst_nid == p->numa_preferred_nid)
+		return 0;
+
+	/* Leaving a core idle is often worse than degrading locality. */
+	if (env->idle == CPU_IDLE)
+		return -1;
+
+	dist = node_distance(src_nid, dst_nid);
+	if (numa_group) {
+		src_weight = group_weight(p, src_nid, dist);
+		dst_weight = group_weight(p, dst_nid, dist);
+	} else {
+		src_weight = task_weight(p, src_nid, dist);
+		dst_weight = task_weight(p, dst_nid, dist);
+	}
+
+	return dst_weight < src_weight;
+}
+
+#else
+static inline int migrate_degrades_locality(struct task_struct *p,
+					     struct lb_env *env)
+{
+	return -1;
+}
+#endif
+
+/*
+ * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
+ */
+static
+int can_migrate_task(struct task_struct *p, struct lb_env *env)
+{
+	int tsk_cache_hot;
+
+	lockdep_assert_rq_held(env->src_rq);
+
+	/*
+	 * We do not migrate tasks that are:
+	 * 1) throttled_lb_pair, or
+	 * 2) cannot be migrated to this CPU due to cpus_ptr, or
+	 * 3) running (obviously), or
+	 * 4) are cache-hot on their current CPU.
+	 */
+	if (throttled_lb_pair(task_group(p), env->src_cpu, env->dst_cpu))
+		return 0;
+
+	/* Disregard pcpu kthreads; they are where they need to be. */
+	if (kthread_is_per_cpu(p))
+		return 0;
+
+	if (!cpumask_test_cpu(env->dst_cpu, p->cpus_ptr)) {
+		int cpu;
+
+		schedstat_inc(p->stats.nr_failed_migrations_affine);
+
+		env->flags |= LBF_SOME_PINNED;
+
+		/*
+		 * Remember if this task can be migrated to any other CPU in
+		 * our sched_group. We may want to revisit it if we couldn't
+		 * meet load balance goals by pulling other tasks on src_cpu.
+		 *
+		 * Avoid computing new_dst_cpu
+		 * - for NEWLY_IDLE
+		 * - if we have already computed one in current iteration
+		 * - if it's an active balance
+		 */
+		if (env->idle == CPU_NEWLY_IDLE ||
+		    env->flags & (LBF_DST_PINNED | LBF_ACTIVE_LB))
+			return 0;
+
+		/* Prevent to re-select dst_cpu via env's CPUs: */
+		for_each_cpu_and(cpu, env->dst_grpmask, env->cpus) {
+			if (cpumask_test_cpu(cpu, p->cpus_ptr)) {
+				env->flags |= LBF_DST_PINNED;
+				env->new_dst_cpu = cpu;
+				break;
+			}
+		}
+
+		return 0;
+	}
+
+	/* Record that we found at least one task that could run on dst_cpu */
+	env->flags &= ~LBF_ALL_PINNED;
+
+	if (task_on_cpu(env->src_rq, p)) {
+		schedstat_inc(p->stats.nr_failed_migrations_running);
+		return 0;
+	}
+
+	/*
+	 * Aggressive migration if:
+	 * 1) active balance
+	 * 2) destination numa is preferred
+	 * 3) task is cache cold, or
+	 * 4) too many balance attempts have failed.
+	 */
+	if (env->flags & LBF_ACTIVE_LB)
+		return 1;
+
+	tsk_cache_hot = migrate_degrades_locality(p, env);
+	if (tsk_cache_hot == -1)
+		tsk_cache_hot = task_hot(p, env);
+
+	if (tsk_cache_hot <= 0 ||
+	    env->sd->nr_balance_failed > env->sd->cache_nice_tries) {
+		if (tsk_cache_hot == 1) {
+			schedstat_inc(env->sd->lb_hot_gained[env->idle]);
+			schedstat_inc(p->stats.nr_forced_migrations);
+		}
+		return 1;
+	}
+
+	schedstat_inc(p->stats.nr_failed_migrations_hot);
+	return 0;
+}
+
+/*
+ * detach_task() -- detach the task for the migration specified in env
+ */
+static void detach_task(struct task_struct *p, struct lb_env *env)
+{
+	lockdep_assert_rq_held(env->src_rq);
+
+	deactivate_task(env->src_rq, p, DEQUEUE_NOCLOCK);
+	set_task_cpu(p, env->dst_cpu);
+}
+
+/*
+ * detach_one_task() -- tries to dequeue exactly one task from env->src_rq, as
+ * part of active balancing operations within "domain".
+ *
+ * Returns a task if successful and NULL otherwise.
+ */
+static struct task_struct *detach_one_task(struct lb_env *env)
+{
+	struct task_struct *p;
+
+	lockdep_assert_rq_held(env->src_rq);
+
+	list_for_each_entry_reverse(p,
+			&env->src_rq->cfs_tasks, se.group_node) {
+		if (!can_migrate_task(p, env))
+			continue;
+
+		detach_task(p, env);
+
+		/*
+		 * Right now, this is only the second place where
+		 * lb_gained[env->idle] is updated (other is detach_tasks)
+		 * so we can safely collect stats here rather than
+		 * inside detach_tasks().
+		 */
+		schedstat_inc(env->sd->lb_gained[env->idle]);
+		return p;
+	}
+	return NULL;
+}
+
+/*
+ * detach_tasks() -- tries to detach up to imbalance load/util/tasks from
+ * busiest_rq, as part of a balancing operation within domain "sd".
+ *
+ * Returns number of detached tasks if successful and 0 otherwise.
+ */
+static int detach_tasks(struct lb_env *env)
+{
+	struct list_head *tasks = &env->src_rq->cfs_tasks;
+	unsigned long util, load;
+	struct task_struct *p;
+	int detached = 0;
+
+	lockdep_assert_rq_held(env->src_rq);
+
+	/*
+	 * Source run queue has been emptied by another CPU, clear
+	 * LBF_ALL_PINNED flag as we will not test any task.
+	 */
+	if (env->src_rq->nr_running <= 1) {
+		env->flags &= ~LBF_ALL_PINNED;
+		return 0;
+	}
+
+	if (env->imbalance <= 0)
+		return 0;
+
+	while (!list_empty(tasks)) {
+		/*
+		 * We don't want to steal all, otherwise we may be treated likewise,
+		 * which could at worst lead to a livelock crash.
+		 */
+		if (env->idle != CPU_NOT_IDLE && env->src_rq->nr_running <= 1)
+			break;
+
+		env->loop++;
+		/*
+		 * We've more or less seen every task there is, call it quits
+		 * unless we haven't found any movable task yet.
+		 */
+		if (env->loop > env->loop_max &&
+		    !(env->flags & LBF_ALL_PINNED))
+			break;
+
+		/* take a breather every nr_migrate tasks */
+		if (env->loop > env->loop_break) {
+			env->loop_break += SCHED_NR_MIGRATE_BREAK;
+			env->flags |= LBF_NEED_BREAK;
+			break;
+		}
+
+		p = list_last_entry(tasks, struct task_struct, se.group_node);
+
+		if (!can_migrate_task(p, env))
+			goto next;
+
+		switch (env->migration_type) {
+		case migrate_load:
+			/*
+			 * Depending of the number of CPUs and tasks and the
+			 * cgroup hierarchy, task_h_load() can return a null
+			 * value. Make sure that env->imbalance decreases
+			 * otherwise detach_tasks() will stop only after
+			 * detaching up to loop_max tasks.
+			 */
+			load = max_t(unsigned long, task_h_load(p), 1);
+
+			if (sched_feat(LB_MIN) &&
+			    load < 16 && !env->sd->nr_balance_failed)
+				goto next;
+
+			/*
+			 * Make sure that we don't migrate too much load.
+			 * Nevertheless, let relax the constraint if
+			 * scheduler fails to find a good waiting task to
+			 * migrate.
+			 */
+			if (shr_bound(load, env->sd->nr_balance_failed) > env->imbalance)
+				goto next;
+
+			env->imbalance -= load;
+			break;
+
+		case migrate_util:
+			util = task_util_est(p);
+
+			if (util > env->imbalance)
+				goto next;
+
+			env->imbalance -= util;
+			break;
+
+		case migrate_task:
+			env->imbalance--;
+			break;
+
+		case migrate_misfit:
+			/* This is not a misfit task */
+			if (task_fits_cpu(p, env->src_cpu))
+				goto next;
+
+			env->imbalance = 0;
+			break;
+		}
+
+		detach_task(p, env);
+		list_add(&p->se.group_node, &env->tasks);
+
+		detached++;
+
+#ifdef CONFIG_PREEMPTION
+		/*
+		 * NEWIDLE balancing is a source of latency, so preemptible
+		 * kernels will stop after the first task is detached to minimize
+		 * the critical section.
+		 */
+		if (env->idle == CPU_NEWLY_IDLE)
+			break;
+#endif
+
+		/*
+		 * We only want to steal up to the prescribed amount of
+		 * load/util/tasks.
+		 */
+		if (env->imbalance <= 0)
+			break;
+
+		continue;
+next:
+		list_move(&p->se.group_node, tasks);
+	}
+
+	/*
+	 * Right now, this is one of only two places we collect this stat
+	 * so we can safely collect detach_one_task() stats here rather
+	 * than inside detach_one_task().
+	 */
+	schedstat_add(env->sd->lb_gained[env->idle], detached);
+
+	return detached;
+}
+
+/*
+ * attach_task() -- attach the task detached by detach_task() to its new rq.
+ */
+static void attach_task(struct rq *rq, struct task_struct *p)
+{
+	lockdep_assert_rq_held(rq);
+
+	WARN_ON_ONCE(task_rq(p) != rq);
+	activate_task(rq, p, ENQUEUE_NOCLOCK);
+	check_preempt_curr(rq, p, 0);
+}
+
+/*
+ * attach_one_task() -- attaches the task returned from detach_one_task() to
+ * its new rq.
+ */
+static void attach_one_task(struct rq *rq, struct task_struct *p)
+{
+	struct rq_flags rf;
+
+	rq_lock(rq, &rf);
+	update_rq_clock(rq);
+	attach_task(rq, p);
+	rq_unlock(rq, &rf);
+}
+
+/*
+ * attach_tasks() -- attaches all tasks detached by detach_tasks() to their
+ * new rq.
+ */
+static void attach_tasks(struct lb_env *env)
+{
+	struct list_head *tasks = &env->tasks;
+	struct task_struct *p;
+	struct rq_flags rf;
+
+	rq_lock(env->dst_rq, &rf);
+	update_rq_clock(env->dst_rq);
+
+	while (!list_empty(tasks)) {
+		p = list_first_entry(tasks, struct task_struct, se.group_node);
+		list_del_init(&p->se.group_node);
+
+		attach_task(env->dst_rq, p);
+	}
+
+	rq_unlock(env->dst_rq, &rf);
+}
+
+#ifdef CONFIG_NO_HZ_COMMON
+static inline bool cfs_rq_has_blocked(struct cfs_rq *cfs_rq)
+{
+	if (cfs_rq->avg.load_avg)
+		return true;
+
+	if (cfs_rq->avg.util_avg)
+		return true;
+
+	return false;
+}
+
+static inline bool others_have_blocked(struct rq *rq)
+{
+	if (READ_ONCE(rq->avg_rt.util_avg))
+		return true;
+
+	if (READ_ONCE(rq->avg_dl.util_avg))
+		return true;
+
+	if (thermal_load_avg(rq))
+		return true;
+
+#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
+	if (READ_ONCE(rq->avg_irq.util_avg))
+		return true;
+#endif
+
+	return false;
+}
+
+static inline void update_blocked_load_tick(struct rq *rq)
+{
+	WRITE_ONCE(rq->last_blocked_load_update_tick, jiffies);
+}
+
+static inline void update_blocked_load_status(struct rq *rq, bool has_blocked)
+{
+	if (!has_blocked)
+		rq->has_blocked_load = 0;
+}
+#else
+static inline bool cfs_rq_has_blocked(struct cfs_rq *cfs_rq) { return false; }
+static inline bool others_have_blocked(struct rq *rq) { return false; }
+static inline void update_blocked_load_tick(struct rq *rq) {}
+static inline void update_blocked_load_status(struct rq *rq, bool has_blocked) {}
+#endif
+
+static bool __update_blocked_others(struct rq *rq, bool *done)
+{
+	const struct sched_class *curr_class;
+	u64 now = rq_clock_pelt(rq);
+	unsigned long thermal_pressure;
+	bool decayed;
+
+	/*
+	 * update_load_avg() can call cpufreq_update_util(). Make sure that RT,
+	 * DL and IRQ signals have been updated before updating CFS.
+	 */
+	curr_class = rq->curr->sched_class;
+
+	thermal_pressure = arch_scale_thermal_pressure(cpu_of(rq));
+
+	decayed = update_rt_rq_load_avg(now, rq, curr_class == &rt_sched_class) |
+		  update_dl_rq_load_avg(now, rq, curr_class == &dl_sched_class) |
+		  update_thermal_load_avg(rq_clock_thermal(rq), rq, thermal_pressure) |
+		  update_irq_load_avg(rq, 0);
+
+	if (others_have_blocked(rq))
+		*done = false;
+
+	return decayed;
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+
+static bool __update_blocked_fair(struct rq *rq, bool *done)
+{
+	struct cfs_rq *cfs_rq, *pos;
+	bool decayed = false;
+	int cpu = cpu_of(rq);
+
+	/*
+	 * Iterates the task_group tree in a bottom up fashion, see
+	 * list_add_leaf_cfs_rq() for details.
+	 */
+	for_each_leaf_cfs_rq_safe(rq, cfs_rq, pos) {
+		struct sched_entity *se;
+
+		if (update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq)) {
+			update_tg_load_avg(cfs_rq);
+
+			if (cfs_rq->nr_running == 0)
+				update_idle_cfs_rq_clock_pelt(cfs_rq);
+
+			if (cfs_rq == &rq->cfs)
+				decayed = true;
+		}
+
+		/* Propagate pending load changes to the parent, if any: */
+		se = cfs_rq->tg->se[cpu];
+		if (se && !skip_blocked_update(se))
+			update_load_avg(cfs_rq_of(se), se, UPDATE_TG);
+
+		/*
+		 * There can be a lot of idle CPU cgroups.  Don't let fully
+		 * decayed cfs_rqs linger on the list.
+		 */
+		if (cfs_rq_is_decayed(cfs_rq))
+			list_del_leaf_cfs_rq(cfs_rq);
+
+		/* Don't need periodic decay once load/util_avg are null */
+		if (cfs_rq_has_blocked(cfs_rq))
+			*done = false;
+	}
+
+	return decayed;
+}
+
+/*
+ * Compute the hierarchical load factor for cfs_rq and all its ascendants.
+ * This needs to be done in a top-down fashion because the load of a child
+ * group is a fraction of its parents load.
+ */
+static void update_cfs_rq_h_load(struct cfs_rq *cfs_rq)
+{
+	struct rq *rq = rq_of(cfs_rq);
+	struct sched_entity *se = cfs_rq->tg->se[cpu_of(rq)];
+	unsigned long now = jiffies;
+	unsigned long load;
+
+	if (cfs_rq->last_h_load_update == now)
+		return;
+
+	WRITE_ONCE(cfs_rq->h_load_next, NULL);
+	for_each_sched_entity(se) {
+		cfs_rq = cfs_rq_of(se);
+		WRITE_ONCE(cfs_rq->h_load_next, se);
+		if (cfs_rq->last_h_load_update == now)
+			break;
+	}
+
+	if (!se) {
+		cfs_rq->h_load = cfs_rq_load_avg(cfs_rq);
+		cfs_rq->last_h_load_update = now;
+	}
+
+	while ((se = READ_ONCE(cfs_rq->h_load_next)) != NULL) {
+		load = cfs_rq->h_load;
+		load = div64_ul(load * se->avg.load_avg,
+			cfs_rq_load_avg(cfs_rq) + 1);
+		cfs_rq = group_cfs_rq(se);
+		cfs_rq->h_load = load;
+		cfs_rq->last_h_load_update = now;
+	}
+}
+
+static unsigned long task_h_load(struct task_struct *p)
+{
+	struct cfs_rq *cfs_rq = task_cfs_rq(p);
+
+	update_cfs_rq_h_load(cfs_rq);
+	return div64_ul(p->se.avg.load_avg * cfs_rq->h_load,
+			cfs_rq_load_avg(cfs_rq) + 1);
+}
+#else
+static bool __update_blocked_fair(struct rq *rq, bool *done)
+{
+	struct cfs_rq *cfs_rq = &rq->cfs;
+	bool decayed;
+
+	decayed = update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq);
+	if (cfs_rq_has_blocked(cfs_rq))
+		*done = false;
+
+	return decayed;
+}
+
+static unsigned long task_h_load(struct task_struct *p)
+{
+	return p->se.avg.load_avg;
+}
+#endif
+
+static void update_blocked_averages(int cpu)
+{
+	bool decayed = false, done = true;
+	struct rq *rq = cpu_rq(cpu);
+	struct rq_flags rf;
+
+	rq_lock_irqsave(rq, &rf);
+	update_blocked_load_tick(rq);
+	update_rq_clock(rq);
+
+	decayed |= __update_blocked_others(rq, &done);
+	decayed |= __update_blocked_fair(rq, &done);
+
+	update_blocked_load_status(rq, !done);
+	if (decayed)
+		cpufreq_update_util(rq, 0);
+	rq_unlock_irqrestore(rq, &rf);
+}
+
+/********** Helpers for find_busiest_group ************************/
+
+/*
+ * sg_lb_stats - stats of a sched_group required for load_balancing
+ */
+struct sg_lb_stats {
+	unsigned long avg_load; /*Avg load across the CPUs of the group */
+	unsigned long group_load; /* Total load over the CPUs of the group */
+	unsigned long group_capacity;
+	unsigned long group_util; /* Total utilization over the CPUs of the group */
+	unsigned long group_runnable; /* Total runnable time over the CPUs of the group */
+	unsigned int sum_nr_running; /* Nr of tasks running in the group */
+	unsigned int sum_h_nr_running; /* Nr of CFS tasks running in the group */
+	unsigned int idle_cpus;
+	unsigned int group_weight;
+	enum group_type group_type;
+	unsigned int group_asym_packing; /* Tasks should be moved to preferred CPU */
+	unsigned int group_smt_balance;  /* Task on busy SMT be moved */
+	unsigned long group_misfit_task_load; /* A CPU has a task too big for its capacity */
+#ifdef CONFIG_NUMA_BALANCING
+	unsigned int nr_numa_running;
+	unsigned int nr_preferred_running;
+#endif
+};
+
+/*
+ * sd_lb_stats - Structure to store the statistics of a sched_domain
+ *		 during load balancing.
+ */
+struct sd_lb_stats {
+	struct sched_group *busiest;	/* Busiest group in this sd */
+	struct sched_group *local;	/* Local group in this sd */
+	unsigned long total_load;	/* Total load of all groups in sd */
+	unsigned long total_capacity;	/* Total capacity of all groups in sd */
+	unsigned long avg_load;	/* Average load across all groups in sd */
+	unsigned int prefer_sibling; /* tasks should go to sibling first */
+
+	struct sg_lb_stats busiest_stat;/* Statistics of the busiest group */
+	struct sg_lb_stats local_stat;	/* Statistics of the local group */
+};
+
+static inline void init_sd_lb_stats(struct sd_lb_stats *sds)
+{
+	/*
+	 * Skimp on the clearing to avoid duplicate work. We can avoid clearing
+	 * local_stat because update_sg_lb_stats() does a full clear/assignment.
+	 * We must however set busiest_stat::group_type and
+	 * busiest_stat::idle_cpus to the worst busiest group because
+	 * update_sd_pick_busiest() reads these before assignment.
+	 */
+	*sds = (struct sd_lb_stats){
+		.busiest = NULL,
+		.local = NULL,
+		.total_load = 0UL,
+		.total_capacity = 0UL,
+		.busiest_stat = {
+			.idle_cpus = UINT_MAX,
+			.group_type = group_has_spare,
+		},
+	};
+}
+
+static unsigned long scale_rt_capacity(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	unsigned long max = arch_scale_cpu_capacity(cpu);
+	unsigned long used, free;
+	unsigned long irq;
+
+	irq = cpu_util_irq(rq);
+
+	if (unlikely(irq >= max))
+		return 1;
+
+	/*
+	 * avg_rt.util_avg and avg_dl.util_avg track binary signals
+	 * (running and not running) with weights 0 and 1024 respectively.
+	 * avg_thermal.load_avg tracks thermal pressure and the weighted
+	 * average uses the actual delta max capacity(load).
+	 */
+	used = READ_ONCE(rq->avg_rt.util_avg);
+	used += READ_ONCE(rq->avg_dl.util_avg);
+	used += thermal_load_avg(rq);
+
+	if (unlikely(used >= max))
+		return 1;
+
+	free = max - used;
+
+	return scale_irq_capacity(free, irq, max);
+}
+
+static void update_cpu_capacity(struct sched_domain *sd, int cpu)
+{
+	unsigned long capacity = scale_rt_capacity(cpu);
+	struct sched_group *sdg = sd->groups;
+
+	cpu_rq(cpu)->cpu_capacity_orig = arch_scale_cpu_capacity(cpu);
+
+	if (!capacity)
+		capacity = 1;
+
+	cpu_rq(cpu)->cpu_capacity = capacity;
+	trace_sched_cpu_capacity_tp(cpu_rq(cpu));
+
+	sdg->sgc->capacity = capacity;
+	sdg->sgc->min_capacity = capacity;
+	sdg->sgc->max_capacity = capacity;
+}
+
+void update_group_capacity(struct sched_domain *sd, int cpu)
+{
+	struct sched_domain *child = sd->child;
+	struct sched_group *group, *sdg = sd->groups;
+	unsigned long capacity, min_capacity, max_capacity;
+	unsigned long interval;
+
+	interval = msecs_to_jiffies(sd->balance_interval);
+	interval = clamp(interval, 1UL, max_load_balance_interval);
+	sdg->sgc->next_update = jiffies + interval;
+
+	if (!child) {
+		update_cpu_capacity(sd, cpu);
+		return;
+	}
+
+	capacity = 0;
+	min_capacity = ULONG_MAX;
+	max_capacity = 0;
+
+	if (child->flags & SD_OVERLAP) {
+		/*
+		 * SD_OVERLAP domains cannot assume that child groups
+		 * span the current group.
+		 */
+
+		for_each_cpu(cpu, sched_group_span(sdg)) {
+			unsigned long cpu_cap = capacity_of(cpu);
+
+			capacity += cpu_cap;
+			min_capacity = min(cpu_cap, min_capacity);
+			max_capacity = max(cpu_cap, max_capacity);
+		}
+	} else  {
+		/*
+		 * !SD_OVERLAP domains can assume that child groups
+		 * span the current group.
+		 */
+
+		group = child->groups;
+		do {
+			struct sched_group_capacity *sgc = group->sgc;
+
+			capacity += sgc->capacity;
+			min_capacity = min(sgc->min_capacity, min_capacity);
+			max_capacity = max(sgc->max_capacity, max_capacity);
+			group = group->next;
+		} while (group != child->groups);
+	}
+
+	sdg->sgc->capacity = capacity;
+	sdg->sgc->min_capacity = min_capacity;
+	sdg->sgc->max_capacity = max_capacity;
+}
+
+/*
+ * Check whether the capacity of the rq has been noticeably reduced by side
+ * activity. The imbalance_pct is used for the threshold.
+ * Return true is the capacity is reduced
+ */
+static inline int
+check_cpu_capacity(struct rq *rq, struct sched_domain *sd)
+{
+	return ((rq->cpu_capacity * sd->imbalance_pct) <
+				(rq->cpu_capacity_orig * 100));
+}
+
+/*
+ * Check whether a rq has a misfit task and if it looks like we can actually
+ * help that task: we can migrate the task to a CPU of higher capacity, or
+ * the task's current CPU is heavily pressured.
+ */
+static inline int check_misfit_status(struct rq *rq, struct sched_domain *sd)
+{
+	return rq->misfit_task_load &&
+		(rq->cpu_capacity_orig < rq->rd->max_cpu_capacity ||
+		 check_cpu_capacity(rq, sd));
+}
+
+/*
+ * Group imbalance indicates (and tries to solve) the problem where balancing
+ * groups is inadequate due to ->cpus_ptr constraints.
+ *
+ * Imagine a situation of two groups of 4 CPUs each and 4 tasks each with a
+ * cpumask covering 1 CPU of the first group and 3 CPUs of the second group.
+ * Something like:
+ *
+ *	{ 0 1 2 3 } { 4 5 6 7 }
+ *	        *     * * *
+ *
+ * If we were to balance group-wise we'd place two tasks in the first group and
+ * two tasks in the second group. Clearly this is undesired as it will overload
+ * cpu 3 and leave one of the CPUs in the second group unused.
+ *
+ * The current solution to this issue is detecting the skew in the first group
+ * by noticing the lower domain failed to reach balance and had difficulty
+ * moving tasks due to affinity constraints.
+ *
+ * When this is so detected; this group becomes a candidate for busiest; see
+ * update_sd_pick_busiest(). And calculate_imbalance() and
+ * find_busiest_group() avoid some of the usual balance conditions to allow it
+ * to create an effective group imbalance.
+ *
+ * This is a somewhat tricky proposition since the next run might not find the
+ * group imbalance and decide the groups need to be balanced again. A most
+ * subtle and fragile situation.
+ */
+
+static inline int sg_imbalanced(struct sched_group *group)
+{
+	return group->sgc->imbalance;
+}
+
+/*
+ * group_has_capacity returns true if the group has spare capacity that could
+ * be used by some tasks.
+ * We consider that a group has spare capacity if the number of task is
+ * smaller than the number of CPUs or if the utilization is lower than the
+ * available capacity for CFS tasks.
+ * For the latter, we use a threshold to stabilize the state, to take into
+ * account the variance of the tasks' load and to return true if the available
+ * capacity in meaningful for the load balancer.
+ * As an example, an available capacity of 1% can appear but it doesn't make
+ * any benefit for the load balance.
+ */
+static inline bool
+group_has_capacity(unsigned int imbalance_pct, struct sg_lb_stats *sgs)
+{
+	if (sgs->sum_nr_running < sgs->group_weight)
+		return true;
+
+	if ((sgs->group_capacity * imbalance_pct) <
+			(sgs->group_runnable * 100))
+		return false;
+
+	if ((sgs->group_capacity * 100) >
+			(sgs->group_util * imbalance_pct))
+		return true;
+
+	return false;
+}
+
+/*
+ *  group_is_overloaded returns true if the group has more tasks than it can
+ *  handle.
+ *  group_is_overloaded is not equals to !group_has_capacity because a group
+ *  with the exact right number of tasks, has no more spare capacity but is not
+ *  overloaded so both group_has_capacity and group_is_overloaded return
+ *  false.
+ */
+static inline bool
+group_is_overloaded(unsigned int imbalance_pct, struct sg_lb_stats *sgs)
+{
+	if (sgs->sum_nr_running <= sgs->group_weight)
+		return false;
+
+	if ((sgs->group_capacity * 100) <
+			(sgs->group_util * imbalance_pct))
+		return true;
+
+	if ((sgs->group_capacity * imbalance_pct) <
+			(sgs->group_runnable * 100))
+		return true;
+
+	return false;
+}
+
+static inline enum
+group_type group_classify(unsigned int imbalance_pct,
+			  struct sched_group *group,
+			  struct sg_lb_stats *sgs)
+{
+	if (group_is_overloaded(imbalance_pct, sgs))
+		return group_overloaded;
+
+	if (sg_imbalanced(group))
+		return group_imbalanced;
+
+	if (sgs->group_asym_packing)
+		return group_asym_packing;
+
+	if (sgs->group_smt_balance)
+		return group_smt_balance;
+
+	if (sgs->group_misfit_task_load)
+		return group_misfit_task;
+
+	if (!group_has_capacity(imbalance_pct, sgs))
+		return group_fully_busy;
+
+	return group_has_spare;
+}
+
+/**
+ * sched_use_asym_prio - Check whether asym_packing priority must be used
+ * @sd:		The scheduling domain of the load balancing
+ * @cpu:	A CPU
+ *
+ * Always use CPU priority when balancing load between SMT siblings. When
+ * balancing load between cores, it is not sufficient that @cpu is idle. Only
+ * use CPU priority if the whole core is idle.
+ *
+ * Returns: True if the priority of @cpu must be followed. False otherwise.
+ */
+static bool sched_use_asym_prio(struct sched_domain *sd, int cpu)
+{
+	if (!sched_smt_active())
+		return true;
+
+	return sd->flags & SD_SHARE_CPUCAPACITY || is_core_idle(cpu);
+}
+
+/**
+ * sched_asym - Check if the destination CPU can do asym_packing load balance
+ * @env:	The load balancing environment
+ * @sds:	Load-balancing data with statistics of the local group
+ * @sgs:	Load-balancing statistics of the candidate busiest group
+ * @group:	The candidate busiest group
+ *
+ * @env::dst_cpu can do asym_packing if it has higher priority than the
+ * preferred CPU of @group.
+ *
+ * SMT is a special case. If we are balancing load between cores, @env::dst_cpu
+ * can do asym_packing balance only if all its SMT siblings are idle. Also, it
+ * can only do it if @group is an SMT group and has exactly on busy CPU. Larger
+ * imbalances in the number of CPUS are dealt with in find_busiest_group().
+ *
+ * If we are balancing load within an SMT core, or at DIE domain level, always
+ * proceed.
+ *
+ * Return: true if @env::dst_cpu can do with asym_packing load balance. False
+ * otherwise.
+ */
+static inline bool
+sched_asym(struct lb_env *env, struct sd_lb_stats *sds,  struct sg_lb_stats *sgs,
+	   struct sched_group *group)
+{
+	/* Ensure that the whole local core is idle, if applicable. */
+	if (!sched_use_asym_prio(env->sd, env->dst_cpu))
+		return false;
+
+	/*
+	 * CPU priorities does not make sense for SMT cores with more than one
+	 * busy sibling.
+	 */
+	if (group->flags & SD_SHARE_CPUCAPACITY) {
+		if (sgs->group_weight - sgs->idle_cpus != 1)
+			return false;
+	}
+
+	return sched_asym_prefer(env->dst_cpu, group->asym_prefer_cpu);
+}
+
+/* One group has more than one SMT CPU while the other group does not */
+static inline bool smt_vs_nonsmt_groups(struct sched_group *sg1,
+				    struct sched_group *sg2)
+{
+	if (!sg1 || !sg2)
+		return false;
+
+	return (sg1->flags & SD_SHARE_CPUCAPACITY) !=
+		(sg2->flags & SD_SHARE_CPUCAPACITY);
+}
+
+static inline bool smt_balance(struct lb_env *env, struct sg_lb_stats *sgs,
+			       struct sched_group *group)
+{
+	if (env->idle == CPU_NOT_IDLE)
+		return false;
+
+	/*
+	 * For SMT source group, it is better to move a task
+	 * to a CPU that doesn't have multiple tasks sharing its CPU capacity.
+	 * Note that if a group has a single SMT, SD_SHARE_CPUCAPACITY
+	 * will not be on.
+	 */
+	if (group->flags & SD_SHARE_CPUCAPACITY &&
+	    sgs->sum_h_nr_running > 1)
+		return true;
+
+	return false;
+}
+
+static inline long sibling_imbalance(struct lb_env *env,
+				    struct sd_lb_stats *sds,
+				    struct sg_lb_stats *busiest,
+				    struct sg_lb_stats *local)
+{
+	int ncores_busiest, ncores_local;
+	long imbalance;
+
+	if (env->idle == CPU_NOT_IDLE || !busiest->sum_nr_running)
+		return 0;
+
+	ncores_busiest = sds->busiest->cores;
+	ncores_local = sds->local->cores;
+
+	if (ncores_busiest == ncores_local) {
+		imbalance = busiest->sum_nr_running;
+		lsub_positive(&imbalance, local->sum_nr_running);
+		return imbalance;
+	}
+
+	/* Balance such that nr_running/ncores ratio are same on both groups */
+	imbalance = ncores_local * busiest->sum_nr_running;
+	lsub_positive(&imbalance, ncores_busiest * local->sum_nr_running);
+	/* Normalize imbalance and do rounding on normalization */
+	imbalance = 2 * imbalance + ncores_local + ncores_busiest;
+	imbalance /= ncores_local + ncores_busiest;
+
+	/* Take advantage of resource in an empty sched group */
+	if (imbalance <= 1 && local->sum_nr_running == 0 &&
+	    busiest->sum_nr_running > 1)
+		imbalance = 2;
+
+	return imbalance;
+}
+
+static inline bool
+sched_reduced_capacity(struct rq *rq, struct sched_domain *sd)
+{
+	/*
+	 * When there is more than 1 task, the group_overloaded case already
+	 * takes care of cpu with reduced capacity
+	 */
+	if (rq->cfs.h_nr_running != 1)
+		return false;
+
+	return check_cpu_capacity(rq, sd);
+}
+
+/**
+ * update_sg_lb_stats - Update sched_group's statistics for load balancing.
+ * @env: The load balancing environment.
+ * @sds: Load-balancing data with statistics of the local group.
+ * @group: sched_group whose statistics are to be updated.
+ * @sgs: variable to hold the statistics for this group.
+ * @sg_status: Holds flag indicating the status of the sched_group
+ */
+static inline void update_sg_lb_stats(struct lb_env *env,
+				      struct sd_lb_stats *sds,
+				      struct sched_group *group,
+				      struct sg_lb_stats *sgs,
+				      int *sg_status)
+{
+	int i, nr_running, local_group;
+
+	memset(sgs, 0, sizeof(*sgs));
+
+	local_group = group == sds->local;
+
+	for_each_cpu_and(i, sched_group_span(group), env->cpus) {
+		struct rq *rq = cpu_rq(i);
+		unsigned long load = cpu_load(rq);
+
+		sgs->group_load += load;
+		sgs->group_util += cpu_util_cfs(i);
+		sgs->group_runnable += cpu_runnable(rq);
+		sgs->sum_h_nr_running += rq->cfs.h_nr_running;
+
+		nr_running = rq->nr_running;
+		sgs->sum_nr_running += nr_running;
+
+		if (nr_running > 1)
+			*sg_status |= SG_OVERLOAD;
+
+		if (cpu_overutilized(i))
+			*sg_status |= SG_OVERUTILIZED;
+
+#ifdef CONFIG_NUMA_BALANCING
+		sgs->nr_numa_running += rq->nr_numa_running;
+		sgs->nr_preferred_running += rq->nr_preferred_running;
+#endif
+		/*
+		 * No need to call idle_cpu() if nr_running is not 0
+		 */
+		if (!nr_running && idle_cpu(i)) {
+			sgs->idle_cpus++;
+			/* Idle cpu can't have misfit task */
+			continue;
+		}
+
+		if (local_group)
+			continue;
+
+		if (env->sd->flags & SD_ASYM_CPUCAPACITY) {
+			/* Check for a misfit task on the cpu */
+			if (sgs->group_misfit_task_load < rq->misfit_task_load) {
+				sgs->group_misfit_task_load = rq->misfit_task_load;
+				*sg_status |= SG_OVERLOAD;
+			}
+		} else if ((env->idle != CPU_NOT_IDLE) &&
+			   sched_reduced_capacity(rq, env->sd)) {
+			/* Check for a task running on a CPU with reduced capacity */
+			if (sgs->group_misfit_task_load < load)
+				sgs->group_misfit_task_load = load;
+		}
+	}
+
+	sgs->group_capacity = group->sgc->capacity;
+
+	sgs->group_weight = group->group_weight;
+
+	/* Check if dst CPU is idle and preferred to this group */
+	if (!local_group && env->sd->flags & SD_ASYM_PACKING &&
+	    env->idle != CPU_NOT_IDLE && sgs->sum_h_nr_running &&
+	    sched_asym(env, sds, sgs, group)) {
+		sgs->group_asym_packing = 1;
+	}
+
+	/* Check for loaded SMT group to be balanced to dst CPU */
+	if (!local_group && smt_balance(env, sgs, group))
+		sgs->group_smt_balance = 1;
+
+	sgs->group_type = group_classify(env->sd->imbalance_pct, group, sgs);
+
+	/* Computing avg_load makes sense only when group is overloaded */
+	if (sgs->group_type == group_overloaded)
+		sgs->avg_load = (sgs->group_load * SCHED_CAPACITY_SCALE) /
+				sgs->group_capacity;
+}
+
+/**
+ * update_sd_pick_busiest - return 1 on busiest group
+ * @env: The load balancing environment.
+ * @sds: sched_domain statistics
+ * @sg: sched_group candidate to be checked for being the busiest
+ * @sgs: sched_group statistics
+ *
+ * Determine if @sg is a busier group than the previously selected
+ * busiest group.
+ *
+ * Return: %true if @sg is a busier group than the previously selected
+ * busiest group. %false otherwise.
+ */
+static bool update_sd_pick_busiest(struct lb_env *env,
+				   struct sd_lb_stats *sds,
+				   struct sched_group *sg,
+				   struct sg_lb_stats *sgs)
+{
+	struct sg_lb_stats *busiest = &sds->busiest_stat;
+
+	/* Make sure that there is at least one task to pull */
+	if (!sgs->sum_h_nr_running)
+		return false;
+
+	/*
+	 * Don't try to pull misfit tasks we can't help.
+	 * We can use max_capacity here as reduction in capacity on some
+	 * CPUs in the group should either be possible to resolve
+	 * internally or be covered by avg_load imbalance (eventually).
+	 */
+	if ((env->sd->flags & SD_ASYM_CPUCAPACITY) &&
+	    (sgs->group_type == group_misfit_task) &&
+	    (!capacity_greater(capacity_of(env->dst_cpu), sg->sgc->max_capacity) ||
+	     sds->local_stat.group_type != group_has_spare))
+		return false;
+
+	if (sgs->group_type > busiest->group_type)
+		return true;
+
+	if (sgs->group_type < busiest->group_type)
+		return false;
+
+	/*
+	 * The candidate and the current busiest group are the same type of
+	 * group. Let check which one is the busiest according to the type.
+	 */
+
+	switch (sgs->group_type) {
+	case group_overloaded:
+		/* Select the overloaded group with highest avg_load. */
+		if (sgs->avg_load <= busiest->avg_load)
+			return false;
+		break;
+
+	case group_imbalanced:
+		/*
+		 * Select the 1st imbalanced group as we don't have any way to
+		 * choose one more than another.
+		 */
+		return false;
+
+	case group_asym_packing:
+		/* Prefer to move from lowest priority CPU's work */
+		if (sched_asym_prefer(sg->asym_prefer_cpu, sds->busiest->asym_prefer_cpu))
+			return false;
+		break;
+
+	case group_misfit_task:
+		/*
+		 * If we have more than one misfit sg go with the biggest
+		 * misfit.
+		 */
+		if (sgs->group_misfit_task_load < busiest->group_misfit_task_load)
+			return false;
+		break;
+
+	case group_smt_balance:
+		/*
+		 * Check if we have spare CPUs on either SMT group to
+		 * choose has spare or fully busy handling.
+		 */
+		if (sgs->idle_cpus != 0 || busiest->idle_cpus != 0)
+			goto has_spare;
+
+		fallthrough;
+
+	case group_fully_busy:
+		/*
+		 * Select the fully busy group with highest avg_load. In
+		 * theory, there is no need to pull task from such kind of
+		 * group because tasks have all compute capacity that they need
+		 * but we can still improve the overall throughput by reducing
+		 * contention when accessing shared HW resources.
+		 *
+		 * XXX for now avg_load is not computed and always 0 so we
+		 * select the 1st one, except if @sg is composed of SMT
+		 * siblings.
+		 */
+
+		if (sgs->avg_load < busiest->avg_load)
+			return false;
+
+		if (sgs->avg_load == busiest->avg_load) {
+			/*
+			 * SMT sched groups need more help than non-SMT groups.
+			 * If @sg happens to also be SMT, either choice is good.
+			 */
+			if (sds->busiest->flags & SD_SHARE_CPUCAPACITY)
+				return false;
+		}
+
+		break;
+
+	case group_has_spare:
+		/*
+		 * Do not pick sg with SMT CPUs over sg with pure CPUs,
+		 * as we do not want to pull task off SMT core with one task
+		 * and make the core idle.
+		 */
+		if (smt_vs_nonsmt_groups(sds->busiest, sg)) {
+			if (sg->flags & SD_SHARE_CPUCAPACITY && sgs->sum_h_nr_running <= 1)
+				return false;
+			else
+				return true;
+		}
+has_spare:
+
+		/*
+		 * Select not overloaded group with lowest number of idle cpus
+		 * and highest number of running tasks. We could also compare
+		 * the spare capacity which is more stable but it can end up
+		 * that the group has less spare capacity but finally more idle
+		 * CPUs which means less opportunity to pull tasks.
+		 */
+		if (sgs->idle_cpus > busiest->idle_cpus)
+			return false;
+		else if ((sgs->idle_cpus == busiest->idle_cpus) &&
+			 (sgs->sum_nr_running <= busiest->sum_nr_running))
+			return false;
+
+		break;
+	}
+
+	/*
+	 * Candidate sg has no more than one task per CPU and has higher
+	 * per-CPU capacity. Migrating tasks to less capable CPUs may harm
+	 * throughput. Maximize throughput, power/energy consequences are not
+	 * considered.
+	 */
+	if ((env->sd->flags & SD_ASYM_CPUCAPACITY) &&
+	    (sgs->group_type <= group_fully_busy) &&
+	    (capacity_greater(sg->sgc->min_capacity, capacity_of(env->dst_cpu))))
+		return false;
+
+	return true;
+}
+
+#ifdef CONFIG_NUMA_BALANCING
+static inline enum fbq_type fbq_classify_group(struct sg_lb_stats *sgs)
+{
+	if (sgs->sum_h_nr_running > sgs->nr_numa_running)
+		return regular;
+	if (sgs->sum_h_nr_running > sgs->nr_preferred_running)
+		return remote;
+	return all;
+}
+
+static inline enum fbq_type fbq_classify_rq(struct rq *rq)
+{
+	if (rq->nr_running > rq->nr_numa_running)
+		return regular;
+	if (rq->nr_running > rq->nr_preferred_running)
+		return remote;
+	return all;
+}
+#else
+static inline enum fbq_type fbq_classify_group(struct sg_lb_stats *sgs)
+{
+	return all;
+}
+
+static inline enum fbq_type fbq_classify_rq(struct rq *rq)
+{
+	return regular;
+}
+#endif /* CONFIG_NUMA_BALANCING */
+
+
+struct sg_lb_stats;
+
+/*
+ * task_running_on_cpu - return 1 if @p is running on @cpu.
+ */
+
+static unsigned int task_running_on_cpu(int cpu, struct task_struct *p)
+{
+	/* Task has no contribution or is new */
+	if (cpu != task_cpu(p) || !READ_ONCE(p->se.avg.last_update_time))
+		return 0;
+
+	if (task_on_rq_queued(p))
+		return 1;
+
+	return 0;
+}
+
+/**
+ * idle_cpu_without - would a given CPU be idle without p ?
+ * @cpu: the processor on which idleness is tested.
+ * @p: task which should be ignored.
+ *
+ * Return: 1 if the CPU would be idle. 0 otherwise.
+ */
+static int idle_cpu_without(int cpu, struct task_struct *p)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	if (rq->curr != rq->idle && rq->curr != p)
+		return 0;
+
+	/*
+	 * rq->nr_running can't be used but an updated version without the
+	 * impact of p on cpu must be used instead. The updated nr_running
+	 * be computed and tested before calling idle_cpu_without().
+	 */
+
+#ifdef CONFIG_SMP
+	if (rq->ttwu_pending)
+		return 0;
+#endif
+
+	return 1;
+}
+
+/*
+ * update_sg_wakeup_stats - Update sched_group's statistics for wakeup.
+ * @sd: The sched_domain level to look for idlest group.
+ * @group: sched_group whose statistics are to be updated.
+ * @sgs: variable to hold the statistics for this group.
+ * @p: The task for which we look for the idlest group/CPU.
+ */
+static inline void update_sg_wakeup_stats(struct sched_domain *sd,
+					  struct sched_group *group,
+					  struct sg_lb_stats *sgs,
+					  struct task_struct *p)
+{
+	int i, nr_running;
+
+	memset(sgs, 0, sizeof(*sgs));
+
+	/* Assume that task can't fit any CPU of the group */
+	if (sd->flags & SD_ASYM_CPUCAPACITY)
+		sgs->group_misfit_task_load = 1;
+
+	for_each_cpu(i, sched_group_span(group)) {
+		struct rq *rq = cpu_rq(i);
+		unsigned int local;
+
+		sgs->group_load += cpu_load_without(rq, p);
+		sgs->group_util += cpu_util_without(i, p);
+		sgs->group_runnable += cpu_runnable_without(rq, p);
+		local = task_running_on_cpu(i, p);
+		sgs->sum_h_nr_running += rq->cfs.h_nr_running - local;
+
+		nr_running = rq->nr_running - local;
+		sgs->sum_nr_running += nr_running;
+
+		/*
+		 * No need to call idle_cpu_without() if nr_running is not 0
+		 */
+		if (!nr_running && idle_cpu_without(i, p))
+			sgs->idle_cpus++;
+
+		/* Check if task fits in the CPU */
+		if (sd->flags & SD_ASYM_CPUCAPACITY &&
+		    sgs->group_misfit_task_load &&
+		    task_fits_cpu(p, i))
+			sgs->group_misfit_task_load = 0;
+
+	}
+
+	sgs->group_capacity = group->sgc->capacity;
+
+	sgs->group_weight = group->group_weight;
+
+	sgs->group_type = group_classify(sd->imbalance_pct, group, sgs);
+
+	/*
+	 * Computing avg_load makes sense only when group is fully busy or
+	 * overloaded
+	 */
+	if (sgs->group_type == group_fully_busy ||
+		sgs->group_type == group_overloaded)
+		sgs->avg_load = (sgs->group_load * SCHED_CAPACITY_SCALE) /
+				sgs->group_capacity;
+}
+
+static bool update_pick_idlest(struct sched_group *idlest,
+			       struct sg_lb_stats *idlest_sgs,
+			       struct sched_group *group,
+			       struct sg_lb_stats *sgs)
+{
+	if (sgs->group_type < idlest_sgs->group_type)
+		return true;
+
+	if (sgs->group_type > idlest_sgs->group_type)
+		return false;
+
+	/*
+	 * The candidate and the current idlest group are the same type of
+	 * group. Let check which one is the idlest according to the type.
+	 */
+
+	switch (sgs->group_type) {
+	case group_overloaded:
+	case group_fully_busy:
+		/* Select the group with lowest avg_load. */
+		if (idlest_sgs->avg_load <= sgs->avg_load)
+			return false;
+		break;
+
+	case group_imbalanced:
+	case group_asym_packing:
+	case group_smt_balance:
+		/* Those types are not used in the slow wakeup path */
+		return false;
+
+	case group_misfit_task:
+		/* Select group with the highest max capacity */
+		if (idlest->sgc->max_capacity >= group->sgc->max_capacity)
+			return false;
+		break;
+
+	case group_has_spare:
+		/* Select group with most idle CPUs */
+		if (idlest_sgs->idle_cpus > sgs->idle_cpus)
+			return false;
+
+		/* Select group with lowest group_util */
+		if (idlest_sgs->idle_cpus == sgs->idle_cpus &&
+			idlest_sgs->group_util <= sgs->group_util)
+			return false;
+
+		break;
+	}
+
+	return true;
+}
+
+/*
+ * find_idlest_group() finds and returns the least busy CPU group within the
+ * domain.
+ *
+ * Assumes p is allowed on at least one CPU in sd.
+ */
+static struct sched_group *
+find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
+{
+	struct sched_group *idlest = NULL, *local = NULL, *group = sd->groups;
+	struct sg_lb_stats local_sgs, tmp_sgs;
+	struct sg_lb_stats *sgs;
+	unsigned long imbalance;
+	struct sg_lb_stats idlest_sgs = {
+			.avg_load = UINT_MAX,
+			.group_type = group_overloaded,
+	};
+
+	do {
+		int local_group;
+
+		/* Skip over this group if it has no CPUs allowed */
+		if (!cpumask_intersects(sched_group_span(group),
+					p->cpus_ptr))
+			continue;
+
+		/* Skip over this group if no cookie matched */
+		if (!sched_group_cookie_match(cpu_rq(this_cpu), p, group))
+			continue;
+
+		local_group = cpumask_test_cpu(this_cpu,
+					       sched_group_span(group));
+
+		if (local_group) {
+			sgs = &local_sgs;
+			local = group;
+		} else {
+			sgs = &tmp_sgs;
+		}
+
+		update_sg_wakeup_stats(sd, group, sgs, p);
+
+		if (!local_group && update_pick_idlest(idlest, &idlest_sgs, group, sgs)) {
+			idlest = group;
+			idlest_sgs = *sgs;
+		}
+
+	} while (group = group->next, group != sd->groups);
+
+
+	/* There is no idlest group to push tasks to */
+	if (!idlest)
+		return NULL;
+
+	/* The local group has been skipped because of CPU affinity */
+	if (!local)
+		return idlest;
+
+	/*
+	 * If the local group is idler than the selected idlest group
+	 * don't try and push the task.
+	 */
+	if (local_sgs.group_type < idlest_sgs.group_type)
+		return NULL;
+
+	/*
+	 * If the local group is busier than the selected idlest group
+	 * try and push the task.
+	 */
+	if (local_sgs.group_type > idlest_sgs.group_type)
+		return idlest;
+
+	switch (local_sgs.group_type) {
+	case group_overloaded:
+	case group_fully_busy:
+
+		/* Calculate allowed imbalance based on load */
+		imbalance = scale_load_down(NICE_0_LOAD) *
+				(sd->imbalance_pct-100) / 100;
+
+		/*
+		 * When comparing groups across NUMA domains, it's possible for
+		 * the local domain to be very lightly loaded relative to the
+		 * remote domains but "imbalance" skews the comparison making
+		 * remote CPUs look much more favourable. When considering
+		 * cross-domain, add imbalance to the load on the remote node
+		 * and consider staying local.
+		 */
+
+		if ((sd->flags & SD_NUMA) &&
+		    ((idlest_sgs.avg_load + imbalance) >= local_sgs.avg_load))
+			return NULL;
+
+		/*
+		 * If the local group is less loaded than the selected
+		 * idlest group don't try and push any tasks.
+		 */
+		if (idlest_sgs.avg_load >= (local_sgs.avg_load + imbalance))
+			return NULL;
+
+		if (100 * local_sgs.avg_load <= sd->imbalance_pct * idlest_sgs.avg_load)
+			return NULL;
+		break;
+
+	case group_imbalanced:
+	case group_asym_packing:
+	case group_smt_balance:
+		/* Those type are not used in the slow wakeup path */
+		return NULL;
+
+	case group_misfit_task:
+		/* Select group with the highest max capacity */
+		if (local->sgc->max_capacity >= idlest->sgc->max_capacity)
+			return NULL;
+		break;
+
+	case group_has_spare:
+#ifdef CONFIG_NUMA
+		if (sd->flags & SD_NUMA) {
+			int imb_numa_nr = sd->imb_numa_nr;
+#ifdef CONFIG_NUMA_BALANCING
+			int idlest_cpu;
+			/*
+			 * If there is spare capacity at NUMA, try to select
+			 * the preferred node
+			 */
+			if (cpu_to_node(this_cpu) == p->numa_preferred_nid)
+				return NULL;
+
+			idlest_cpu = cpumask_first(sched_group_span(idlest));
+			if (cpu_to_node(idlest_cpu) == p->numa_preferred_nid)
+				return idlest;
+#endif /* CONFIG_NUMA_BALANCING */
+			/*
+			 * Otherwise, keep the task close to the wakeup source
+			 * and improve locality if the number of running tasks
+			 * would remain below threshold where an imbalance is
+			 * allowed while accounting for the possibility the
+			 * task is pinned to a subset of CPUs. If there is a
+			 * real need of migration, periodic load balance will
+			 * take care of it.
+			 */
+			if (p->nr_cpus_allowed != NR_CPUS) {
+				struct cpumask *cpus = this_cpu_cpumask_var_ptr(select_rq_mask);
+
+				cpumask_and(cpus, sched_group_span(local), p->cpus_ptr);
+				imb_numa_nr = min(cpumask_weight(cpus), sd->imb_numa_nr);
+			}
+
+			imbalance = abs(local_sgs.idle_cpus - idlest_sgs.idle_cpus);
+			if (!adjust_numa_imbalance(imbalance,
+						   local_sgs.sum_nr_running + 1,
+						   imb_numa_nr)) {
+				return NULL;
+			}
+		}
+#endif /* CONFIG_NUMA */
+
+		/*
+		 * Select group with highest number of idle CPUs. We could also
+		 * compare the utilization which is more stable but it can end
+		 * up that the group has less spare capacity but finally more
+		 * idle CPUs which means more opportunity to run task.
+		 */
+		if (local_sgs.idle_cpus >= idlest_sgs.idle_cpus)
+			return NULL;
+		break;
+	}
+
+	return idlest;
+}
+
+static void update_idle_cpu_scan(struct lb_env *env,
+				 unsigned long sum_util)
+{
+	struct sched_domain_shared *sd_share;
+	int llc_weight, pct;
+	u64 x, y, tmp;
+	/*
+	 * Update the number of CPUs to scan in LLC domain, which could
+	 * be used as a hint in select_idle_cpu(). The update of sd_share
+	 * could be expensive because it is within a shared cache line.
+	 * So the write of this hint only occurs during periodic load
+	 * balancing, rather than CPU_NEWLY_IDLE, because the latter
+	 * can fire way more frequently than the former.
+	 */
+	if (!sched_feat(SIS_UTIL) || env->idle == CPU_NEWLY_IDLE)
+		return;
+
+	llc_weight = per_cpu(sd_llc_size, env->dst_cpu);
+	if (env->sd->span_weight != llc_weight)
+		return;
+
+	sd_share = rcu_dereference(per_cpu(sd_llc_shared, env->dst_cpu));
+	if (!sd_share)
+		return;
+
+	/*
+	 * The number of CPUs to search drops as sum_util increases, when
+	 * sum_util hits 85% or above, the scan stops.
+	 * The reason to choose 85% as the threshold is because this is the
+	 * imbalance_pct(117) when a LLC sched group is overloaded.
+	 *
+	 * let y = SCHED_CAPACITY_SCALE - p * x^2                       [1]
+	 * and y'= y / SCHED_CAPACITY_SCALE
+	 *
+	 * x is the ratio of sum_util compared to the CPU capacity:
+	 * x = sum_util / (llc_weight * SCHED_CAPACITY_SCALE)
+	 * y' is the ratio of CPUs to be scanned in the LLC domain,
+	 * and the number of CPUs to scan is calculated by:
+	 *
+	 * nr_scan = llc_weight * y'                                    [2]
+	 *
+	 * When x hits the threshold of overloaded, AKA, when
+	 * x = 100 / pct, y drops to 0. According to [1],
+	 * p should be SCHED_CAPACITY_SCALE * pct^2 / 10000
+	 *
+	 * Scale x by SCHED_CAPACITY_SCALE:
+	 * x' = sum_util / llc_weight;                                  [3]
+	 *
+	 * and finally [1] becomes:
+	 * y = SCHED_CAPACITY_SCALE -
+	 *     x'^2 * pct^2 / (10000 * SCHED_CAPACITY_SCALE)            [4]
+	 *
+	 */
+	/* equation [3] */
+	x = sum_util;
+	do_div(x, llc_weight);
+
+	/* equation [4] */
+	pct = env->sd->imbalance_pct;
+	tmp = x * x * pct * pct;
+	do_div(tmp, 10000 * SCHED_CAPACITY_SCALE);
+	tmp = min_t(long, tmp, SCHED_CAPACITY_SCALE);
+	y = SCHED_CAPACITY_SCALE - tmp;
+
+	/* equation [2] */
+	y *= llc_weight;
+	do_div(y, SCHED_CAPACITY_SCALE);
+	if ((int)y != sd_share->nr_idle_scan)
+		WRITE_ONCE(sd_share->nr_idle_scan, (int)y);
+}
+
+/**
+ * update_sd_lb_stats - Update sched_domain's statistics for load balancing.
+ * @env: The load balancing environment.
+ * @sds: variable to hold the statistics for this sched_domain.
+ */
+
+static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sds)
+{
+	struct sched_group *sg = env->sd->groups;
+	struct sg_lb_stats *local = &sds->local_stat;
+	struct sg_lb_stats tmp_sgs;
+	unsigned long sum_util = 0;
+	int sg_status = 0;
+
+	do {
+		struct sg_lb_stats *sgs = &tmp_sgs;
+		int local_group;
+
+		local_group = cpumask_test_cpu(env->dst_cpu, sched_group_span(sg));
+		if (local_group) {
+			sds->local = sg;
+			sgs = local;
+
+			if (env->idle != CPU_NEWLY_IDLE ||
+			    time_after_eq(jiffies, sg->sgc->next_update))
+				update_group_capacity(env->sd, env->dst_cpu);
+		}
+
+		update_sg_lb_stats(env, sds, sg, sgs, &sg_status);
+
+		if (local_group)
+			goto next_group;
+
+
+		if (update_sd_pick_busiest(env, sds, sg, sgs)) {
+			sds->busiest = sg;
+			sds->busiest_stat = *sgs;
+		}
+
+next_group:
+		/* Now, start updating sd_lb_stats */
+		sds->total_load += sgs->group_load;
+		sds->total_capacity += sgs->group_capacity;
+
+		sum_util += sgs->group_util;
+		sg = sg->next;
+	} while (sg != env->sd->groups);
+
+	/*
+	 * Indicate that the child domain of the busiest group prefers tasks
+	 * go to a child's sibling domains first. NB the flags of a sched group
+	 * are those of the child domain.
+	 */
+	if (sds->busiest)
+		sds->prefer_sibling = !!(sds->busiest->flags & SD_PREFER_SIBLING);
+
+
+	if (env->sd->flags & SD_NUMA)
+		env->fbq_type = fbq_classify_group(&sds->busiest_stat);
+
+	if (!env->sd->parent) {
+		struct root_domain *rd = env->dst_rq->rd;
+
+		/* update overload indicator if we are at root domain */
+		WRITE_ONCE(rd->overload, sg_status & SG_OVERLOAD);
+
+		/* Update over-utilization (tipping point, U >= 0) indicator */
+		WRITE_ONCE(rd->overutilized, sg_status & SG_OVERUTILIZED);
+		trace_sched_overutilized_tp(rd, sg_status & SG_OVERUTILIZED);
+	} else if (sg_status & SG_OVERUTILIZED) {
+		struct root_domain *rd = env->dst_rq->rd;
+
+		WRITE_ONCE(rd->overutilized, SG_OVERUTILIZED);
+		trace_sched_overutilized_tp(rd, SG_OVERUTILIZED);
+	}
+
+	update_idle_cpu_scan(env, sum_util);
+}
+
+/**
+ * calculate_imbalance - Calculate the amount of imbalance present within the
+ *			 groups of a given sched_domain during load balance.
+ * @env: load balance environment
+ * @sds: statistics of the sched_domain whose imbalance is to be calculated.
+ */
+static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *sds)
+{
+	struct sg_lb_stats *local, *busiest;
+
+	local = &sds->local_stat;
+	busiest = &sds->busiest_stat;
+
+	if (busiest->group_type == group_misfit_task) {
+		if (env->sd->flags & SD_ASYM_CPUCAPACITY) {
+			/* Set imbalance to allow misfit tasks to be balanced. */
+			env->migration_type = migrate_misfit;
+			env->imbalance = 1;
+		} else {
+			/*
+			 * Set load imbalance to allow moving task from cpu
+			 * with reduced capacity.
+			 */
+			env->migration_type = migrate_load;
+			env->imbalance = busiest->group_misfit_task_load;
+		}
+		return;
+	}
+
+	if (busiest->group_type == group_asym_packing) {
+		/*
+		 * In case of asym capacity, we will try to migrate all load to
+		 * the preferred CPU.
+		 */
+		env->migration_type = migrate_task;
+		env->imbalance = busiest->sum_h_nr_running;
+		return;
+	}
+
+	if (busiest->group_type == group_smt_balance) {
+		/* Reduce number of tasks sharing CPU capacity */
+		env->migration_type = migrate_task;
+		env->imbalance = 1;
+		return;
+	}
+
+	if (busiest->group_type == group_imbalanced) {
+		/*
+		 * In the group_imb case we cannot rely on group-wide averages
+		 * to ensure CPU-load equilibrium, try to move any task to fix
+		 * the imbalance. The next load balance will take care of
+		 * balancing back the system.
+		 */
+		env->migration_type = migrate_task;
+		env->imbalance = 1;
+		return;
+	}
+
+	/*
+	 * Try to use spare capacity of local group without overloading it or
+	 * emptying busiest.
+	 */
+	if (local->group_type == group_has_spare) {
+		if ((busiest->group_type > group_fully_busy) &&
+		    !(env->sd->flags & SD_SHARE_PKG_RESOURCES)) {
+			/*
+			 * If busiest is overloaded, try to fill spare
+			 * capacity. This might end up creating spare capacity
+			 * in busiest or busiest still being overloaded but
+			 * there is no simple way to directly compute the
+			 * amount of load to migrate in order to balance the
+			 * system.
+			 */
+			env->migration_type = migrate_util;
+			env->imbalance = max(local->group_capacity, local->group_util) -
+					 local->group_util;
+
+			/*
+			 * In some cases, the group's utilization is max or even
+			 * higher than capacity because of migrations but the
+			 * local CPU is (newly) idle. There is at least one
+			 * waiting task in this overloaded busiest group. Let's
+			 * try to pull it.
+			 */
+			if (env->idle != CPU_NOT_IDLE && env->imbalance == 0) {
+				env->migration_type = migrate_task;
+				env->imbalance = 1;
+			}
+
+			return;
+		}
+
+		if (busiest->group_weight == 1 || sds->prefer_sibling) {
+			/*
+			 * When prefer sibling, evenly spread running tasks on
+			 * groups.
+			 */
+			env->migration_type = migrate_task;
+			env->imbalance = sibling_imbalance(env, sds, busiest, local);
+		} else {
+
+			/*
+			 * If there is no overload, we just want to even the number of
+			 * idle cpus.
+			 */
+			env->migration_type = migrate_task;
+			env->imbalance = max_t(long, 0,
+					       (local->idle_cpus - busiest->idle_cpus));
+		}
+
+#ifdef CONFIG_NUMA
+		/* Consider allowing a small imbalance between NUMA groups */
+		if (env->sd->flags & SD_NUMA) {
+			env->imbalance = adjust_numa_imbalance(env->imbalance,
+							       local->sum_nr_running + 1,
+							       env->sd->imb_numa_nr);
+		}
+#endif
+
+		/* Number of tasks to move to restore balance */
+		env->imbalance >>= 1;
+
+		return;
+	}
+
+	/*
+	 * Local is fully busy but has to take more load to relieve the
+	 * busiest group
+	 */
+	if (local->group_type < group_overloaded) {
+		/*
+		 * Local will become overloaded so the avg_load metrics are
+		 * finally needed.
+		 */
+
+		local->avg_load = (local->group_load * SCHED_CAPACITY_SCALE) /
+				  local->group_capacity;
+
+		/*
+		 * If the local group is more loaded than the selected
+		 * busiest group don't try to pull any tasks.
+		 */
+		if (local->avg_load >= busiest->avg_load) {
+			env->imbalance = 0;
+			return;
+		}
+
+		sds->avg_load = (sds->total_load * SCHED_CAPACITY_SCALE) /
+				sds->total_capacity;
+
+		/*
+		 * If the local group is more loaded than the average system
+		 * load, don't try to pull any tasks.
+		 */
+		if (local->avg_load >= sds->avg_load) {
+			env->imbalance = 0;
+			return;
+		}
+
+	}
+
+	/*
+	 * Both group are or will become overloaded and we're trying to get all
+	 * the CPUs to the average_load, so we don't want to push ourselves
+	 * above the average load, nor do we wish to reduce the max loaded CPU
+	 * below the average load. At the same time, we also don't want to
+	 * reduce the group load below the group capacity. Thus we look for
+	 * the minimum possible imbalance.
+	 */
+	env->migration_type = migrate_load;
+	env->imbalance = min(
+		(busiest->avg_load - sds->avg_load) * busiest->group_capacity,
+		(sds->avg_load - local->avg_load) * local->group_capacity
+	) / SCHED_CAPACITY_SCALE;
+}
+
+/******* find_busiest_group() helpers end here *********************/
+
+/*
+ * Decision matrix according to the local and busiest group type:
+ *
+ * busiest \ local has_spare fully_busy misfit asym imbalanced overloaded
+ * has_spare        nr_idle   balanced   N/A    N/A  balanced   balanced
+ * fully_busy       nr_idle   nr_idle    N/A    N/A  balanced   balanced
+ * misfit_task      force     N/A        N/A    N/A  N/A        N/A
+ * asym_packing     force     force      N/A    N/A  force      force
+ * imbalanced       force     force      N/A    N/A  force      force
+ * overloaded       force     force      N/A    N/A  force      avg_load
+ *
+ * N/A :      Not Applicable because already filtered while updating
+ *            statistics.
+ * balanced : The system is balanced for these 2 groups.
+ * force :    Calculate the imbalance as load migration is probably needed.
+ * avg_load : Only if imbalance is significant enough.
+ * nr_idle :  dst_cpu is not busy and the number of idle CPUs is quite
+ *            different in groups.
+ */
+
+/**
+ * find_busiest_group - Returns the busiest group within the sched_domain
+ * if there is an imbalance.
+ * @env: The load balancing environment.
+ *
+ * Also calculates the amount of runnable load which should be moved
+ * to restore balance.
+ *
+ * Return:	- The busiest group if imbalance exists.
+ */
+static struct sched_group *find_busiest_group(struct lb_env *env)
+{
+	struct sg_lb_stats *local, *busiest;
+	struct sd_lb_stats sds;
+
+	init_sd_lb_stats(&sds);
+
+	/*
+	 * Compute the various statistics relevant for load balancing at
+	 * this level.
+	 */
+	update_sd_lb_stats(env, &sds);
+
+	/* There is no busy sibling group to pull tasks from */
+	if (!sds.busiest)
+		goto out_balanced;
+
+	busiest = &sds.busiest_stat;
+
+	/* Misfit tasks should be dealt with regardless of the avg load */
+	if (busiest->group_type == group_misfit_task)
+		goto force_balance;
+
+	if (sched_energy_enabled()) {
+		struct root_domain *rd = env->dst_rq->rd;
+
+		if (rcu_dereference(rd->pd) && !READ_ONCE(rd->overutilized))
+			goto out_balanced;
+	}
+
+	/* ASYM feature bypasses nice load balance check */
+	if (busiest->group_type == group_asym_packing)
+		goto force_balance;
+
+	/*
+	 * If the busiest group is imbalanced the below checks don't
+	 * work because they assume all things are equal, which typically
+	 * isn't true due to cpus_ptr constraints and the like.
+	 */
+	if (busiest->group_type == group_imbalanced)
+		goto force_balance;
+
+	local = &sds.local_stat;
+	/*
+	 * If the local group is busier than the selected busiest group
+	 * don't try and pull any tasks.
+	 */
+	if (local->group_type > busiest->group_type)
+		goto out_balanced;
+
+	/*
+	 * When groups are overloaded, use the avg_load to ensure fairness
+	 * between tasks.
+	 */
+	if (local->group_type == group_overloaded) {
+		/*
+		 * If the local group is more loaded than the selected
+		 * busiest group don't try to pull any tasks.
+		 */
+		if (local->avg_load >= busiest->avg_load)
+			goto out_balanced;
+
+		/* XXX broken for overlapping NUMA groups */
+		sds.avg_load = (sds.total_load * SCHED_CAPACITY_SCALE) /
+				sds.total_capacity;
+
+		/*
+		 * Don't pull any tasks if this group is already above the
+		 * domain average load.
+		 */
+		if (local->avg_load >= sds.avg_load)
+			goto out_balanced;
+
+		/*
+		 * If the busiest group is more loaded, use imbalance_pct to be
+		 * conservative.
+		 */
+		if (100 * busiest->avg_load <=
+				env->sd->imbalance_pct * local->avg_load)
+			goto out_balanced;
+	}
+
+	/*
+	 * Try to move all excess tasks to a sibling domain of the busiest
+	 * group's child domain.
+	 */
+	if (sds.prefer_sibling && local->group_type == group_has_spare &&
+	    sibling_imbalance(env, &sds, busiest, local) > 1)
+		goto force_balance;
+
+	if (busiest->group_type != group_overloaded) {
+		if (env->idle == CPU_NOT_IDLE) {
+			/*
+			 * If the busiest group is not overloaded (and as a
+			 * result the local one too) but this CPU is already
+			 * busy, let another idle CPU try to pull task.
+			 */
+			goto out_balanced;
+		}
+
+		if (busiest->group_type == group_smt_balance &&
+		    smt_vs_nonsmt_groups(sds.local, sds.busiest)) {
+			/* Let non SMT CPU pull from SMT CPU sharing with sibling */
+			goto force_balance;
+		}
+
+		if (busiest->group_weight > 1 &&
+		    local->idle_cpus <= (busiest->idle_cpus + 1)) {
+			/*
+			 * If the busiest group is not overloaded
+			 * and there is no imbalance between this and busiest
+			 * group wrt idle CPUs, it is balanced. The imbalance
+			 * becomes significant if the diff is greater than 1
+			 * otherwise we might end up to just move the imbalance
+			 * on another group. Of course this applies only if
+			 * there is more than 1 CPU per group.
+			 */
+			goto out_balanced;
+		}
+
+		if (busiest->sum_h_nr_running == 1) {
+			/*
+			 * busiest doesn't have any tasks waiting to run
+			 */
+			goto out_balanced;
+		}
+	}
+
+force_balance:
+	/* Looks like there is an imbalance. Compute it */
+	calculate_imbalance(env, &sds);
+	return env->imbalance ? sds.busiest : NULL;
+
+out_balanced:
+	env->imbalance = 0;
+	return NULL;
+}
+
+/*
+ * find_busiest_queue - find the busiest runqueue among the CPUs in the group.
+ */
+static struct rq *find_busiest_queue(struct lb_env *env,
+				     struct sched_group *group)
+{
+	struct rq *busiest = NULL, *rq;
+	unsigned long busiest_util = 0, busiest_load = 0, busiest_capacity = 1;
+	unsigned int busiest_nr = 0;
+	int i;
+
+	for_each_cpu_and(i, sched_group_span(group), env->cpus) {
+		unsigned long capacity, load, util;
+		unsigned int nr_running;
+		enum fbq_type rt;
+
+		rq = cpu_rq(i);
+		rt = fbq_classify_rq(rq);
+
+		/*
+		 * We classify groups/runqueues into three groups:
+		 *  - regular: there are !numa tasks
+		 *  - remote:  there are numa tasks that run on the 'wrong' node
+		 *  - all:     there is no distinction
+		 *
+		 * In order to avoid migrating ideally placed numa tasks,
+		 * ignore those when there's better options.
+		 *
+		 * If we ignore the actual busiest queue to migrate another
+		 * task, the next balance pass can still reduce the busiest
+		 * queue by moving tasks around inside the node.
+		 *
+		 * If we cannot move enough load due to this classification
+		 * the next pass will adjust the group classification and
+		 * allow migration of more tasks.
+		 *
+		 * Both cases only affect the total convergence complexity.
+		 */
+		if (rt > env->fbq_type)
+			continue;
+
+		nr_running = rq->cfs.h_nr_running;
+		if (!nr_running)
+			continue;
+
+		capacity = capacity_of(i);
+
+		/*
+		 * For ASYM_CPUCAPACITY domains, don't pick a CPU that could
+		 * eventually lead to active_balancing high->low capacity.
+		 * Higher per-CPU capacity is considered better than balancing
+		 * average load.
+		 */
+		if (env->sd->flags & SD_ASYM_CPUCAPACITY &&
+		    !capacity_greater(capacity_of(env->dst_cpu), capacity) &&
+		    nr_running == 1)
+			continue;
+
+		/*
+		 * Make sure we only pull tasks from a CPU of lower priority
+		 * when balancing between SMT siblings.
+		 *
+		 * If balancing between cores, let lower priority CPUs help
+		 * SMT cores with more than one busy sibling.
+		 */
+		if ((env->sd->flags & SD_ASYM_PACKING) &&
+		    sched_use_asym_prio(env->sd, i) &&
+		    sched_asym_prefer(i, env->dst_cpu) &&
+		    nr_running == 1)
+			continue;
+
+		switch (env->migration_type) {
+		case migrate_load:
+			/*
+			 * When comparing with load imbalance, use cpu_load()
+			 * which is not scaled with the CPU capacity.
+			 */
+			load = cpu_load(rq);
+
+			if (nr_running == 1 && load > env->imbalance &&
+			    !check_cpu_capacity(rq, env->sd))
+				break;
+
+			/*
+			 * For the load comparisons with the other CPUs,
+			 * consider the cpu_load() scaled with the CPU
+			 * capacity, so that the load can be moved away
+			 * from the CPU that is potentially running at a
+			 * lower capacity.
+			 *
+			 * Thus we're looking for max(load_i / capacity_i),
+			 * crosswise multiplication to rid ourselves of the
+			 * division works out to:
+			 * load_i * capacity_j > load_j * capacity_i;
+			 * where j is our previous maximum.
+			 */
+			if (load * busiest_capacity > busiest_load * capacity) {
+				busiest_load = load;
+				busiest_capacity = capacity;
+				busiest = rq;
+			}
+			break;
+
+		case migrate_util:
+			util = cpu_util_cfs_boost(i);
+
+			/*
+			 * Don't try to pull utilization from a CPU with one
+			 * running task. Whatever its utilization, we will fail
+			 * detach the task.
+			 */
+			if (nr_running <= 1)
+				continue;
+
+			if (busiest_util < util) {
+				busiest_util = util;
+				busiest = rq;
+			}
+			break;
+
+		case migrate_task:
+			if (busiest_nr < nr_running) {
+				busiest_nr = nr_running;
+				busiest = rq;
+			}
+			break;
+
+		case migrate_misfit:
+			/*
+			 * For ASYM_CPUCAPACITY domains with misfit tasks we
+			 * simply seek the "biggest" misfit task.
+			 */
+			if (rq->misfit_task_load > busiest_load) {
+				busiest_load = rq->misfit_task_load;
+				busiest = rq;
+			}
+
+			break;
+
+		}
+	}
+
+	return busiest;
+}
+
+/*
+ * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
+ * so long as it is large enough.
+ */
+#define MAX_PINNED_INTERVAL	512
+
+static inline bool
+asym_active_balance(struct lb_env *env)
+{
+	/*
+	 * ASYM_PACKING needs to force migrate tasks from busy but lower
+	 * priority CPUs in order to pack all tasks in the highest priority
+	 * CPUs. When done between cores, do it only if the whole core if the
+	 * whole core is idle.
+	 *
+	 * If @env::src_cpu is an SMT core with busy siblings, let
+	 * the lower priority @env::dst_cpu help it. Do not follow
+	 * CPU priority.
+	 */
+	return env->idle != CPU_NOT_IDLE && (env->sd->flags & SD_ASYM_PACKING) &&
+	       sched_use_asym_prio(env->sd, env->dst_cpu) &&
+	       (sched_asym_prefer(env->dst_cpu, env->src_cpu) ||
+		!sched_use_asym_prio(env->sd, env->src_cpu));
+}
+
+static inline bool
+imbalanced_active_balance(struct lb_env *env)
+{
+	struct sched_domain *sd = env->sd;
+
+	/*
+	 * The imbalanced case includes the case of pinned tasks preventing a fair
+	 * distribution of the load on the system but also the even distribution of the
+	 * threads on a system with spare capacity
+	 */
+	if ((env->migration_type == migrate_task) &&
+	    (sd->nr_balance_failed > sd->cache_nice_tries+2))
+		return 1;
+
+	return 0;
+}
+
+static int need_active_balance(struct lb_env *env)
+{
+	struct sched_domain *sd = env->sd;
+
+	if (asym_active_balance(env))
+		return 1;
+
+	if (imbalanced_active_balance(env))
+		return 1;
+
+	/*
+	 * The dst_cpu is idle and the src_cpu CPU has only 1 CFS task.
+	 * It's worth migrating the task if the src_cpu's capacity is reduced
+	 * because of other sched_class or IRQs if more capacity stays
+	 * available on dst_cpu.
+	 */
+	if ((env->idle != CPU_NOT_IDLE) &&
+	    (env->src_rq->cfs.h_nr_running == 1)) {
+		if ((check_cpu_capacity(env->src_rq, sd)) &&
+		    (capacity_of(env->src_cpu)*sd->imbalance_pct < capacity_of(env->dst_cpu)*100))
+			return 1;
+	}
+
+	if (env->migration_type == migrate_misfit)
+		return 1;
+
+	return 0;
+}
+
+static int active_load_balance_cpu_stop(void *data);
+
+static int should_we_balance(struct lb_env *env)
+{
+	struct cpumask *swb_cpus = this_cpu_cpumask_var_ptr(should_we_balance_tmpmask);
+	struct sched_group *sg = env->sd->groups;
+	int cpu, idle_smt = -1;
+
+	/*
+	 * Ensure the balancing environment is consistent; can happen
+	 * when the softirq triggers 'during' hotplug.
+	 */
+	if (!cpumask_test_cpu(env->dst_cpu, env->cpus))
+		return 0;
+
+	/*
+	 * In the newly idle case, we will allow all the CPUs
+	 * to do the newly idle load balance.
+	 *
+	 * However, we bail out if we already have tasks or a wakeup pending,
+	 * to optimize wakeup latency.
+	 */
+	if (env->idle == CPU_NEWLY_IDLE) {
+		if (env->dst_rq->nr_running > 0 || env->dst_rq->ttwu_pending)
+			return 0;
+		return 1;
+	}
+
+	cpumask_copy(swb_cpus, group_balance_mask(sg));
+	/* Try to find first idle CPU */
+	for_each_cpu_and(cpu, swb_cpus, env->cpus) {
+		if (!idle_cpu(cpu))
+			continue;
+
+		/*
+		 * Don't balance to idle SMT in busy core right away when
+		 * balancing cores, but remember the first idle SMT CPU for
+		 * later consideration.  Find CPU on an idle core first.
+		 */
+		if (!(env->sd->flags & SD_SHARE_CPUCAPACITY) && !is_core_idle(cpu)) {
+			if (idle_smt == -1)
+				idle_smt = cpu;
+			/*
+			 * If the core is not idle, and first SMT sibling which is
+			 * idle has been found, then its not needed to check other
+			 * SMT siblings for idleness:
+			 */
+#ifdef CONFIG_SCHED_SMT
+			cpumask_andnot(swb_cpus, swb_cpus, cpu_smt_mask(cpu));
+#endif
+			continue;
+		}
+
+		/*
+		 * Are we the first idle core in a non-SMT domain or higher,
+		 * or the first idle CPU in a SMT domain?
+		 */
+		return cpu == env->dst_cpu;
+	}
+
+	/* Are we the first idle CPU with busy siblings? */
+	if (idle_smt != -1)
+		return idle_smt == env->dst_cpu;
+
+	/* Are we the first CPU of this group ? */
+	return group_balance_cpu(sg) == env->dst_cpu;
+}
+
+/*
+ * Check this_cpu to ensure it is balanced within domain. Attempt to move
+ * tasks if there is an imbalance.
+ */
+static int load_balance(int this_cpu, struct rq *this_rq,
+			struct sched_domain *sd, enum cpu_idle_type idle,
+			int *continue_balancing)
+{
+	int ld_moved, cur_ld_moved, active_balance = 0;
+	struct sched_domain *sd_parent = sd->parent;
+	struct sched_group *group;
+	struct rq *busiest;
+	struct rq_flags rf;
+	struct cpumask *cpus = this_cpu_cpumask_var_ptr(load_balance_mask);
+	struct lb_env env = {
+		.sd		= sd,
+		.dst_cpu	= this_cpu,
+		.dst_rq		= this_rq,
+		.dst_grpmask    = group_balance_mask(sd->groups),
+		.idle		= idle,
+		.loop_break	= SCHED_NR_MIGRATE_BREAK,
+		.cpus		= cpus,
+		.fbq_type	= all,
+		.tasks		= LIST_HEAD_INIT(env.tasks),
+	};
+
+	cpumask_and(cpus, sched_domain_span(sd), cpu_active_mask);
+
+	schedstat_inc(sd->lb_count[idle]);
+
+redo:
+	if (!should_we_balance(&env)) {
+		*continue_balancing = 0;
+		goto out_balanced;
+	}
+
+	group = find_busiest_group(&env);
+	if (!group) {
+		schedstat_inc(sd->lb_nobusyg[idle]);
+		goto out_balanced;
+	}
+
+	busiest = find_busiest_queue(&env, group);
+	if (!busiest) {
+		schedstat_inc(sd->lb_nobusyq[idle]);
+		goto out_balanced;
+	}
+
+	WARN_ON_ONCE(busiest == env.dst_rq);
+
+	schedstat_add(sd->lb_imbalance[idle], env.imbalance);
+
+	env.src_cpu = busiest->cpu;
+	env.src_rq = busiest;
+
+	ld_moved = 0;
+	/* Clear this flag as soon as we find a pullable task */
+	env.flags |= LBF_ALL_PINNED;
+	if (busiest->nr_running > 1) {
+		/*
+		 * Attempt to move tasks. If find_busiest_group has found
+		 * an imbalance but busiest->nr_running <= 1, the group is
+		 * still unbalanced. ld_moved simply stays zero, so it is
+		 * correctly treated as an imbalance.
+		 */
+		env.loop_max  = min(sysctl_sched_nr_migrate, busiest->nr_running);
+
+more_balance:
+		rq_lock_irqsave(busiest, &rf);
+		update_rq_clock(busiest);
+
+		/*
+		 * cur_ld_moved - load moved in current iteration
+		 * ld_moved     - cumulative load moved across iterations
+		 */
+		cur_ld_moved = detach_tasks(&env);
+
+		/*
+		 * We've detached some tasks from busiest_rq. Every
+		 * task is masked "TASK_ON_RQ_MIGRATING", so we can safely
+		 * unlock busiest->lock, and we are able to be sure
+		 * that nobody can manipulate the tasks in parallel.
+		 * See task_rq_lock() family for the details.
+		 */
+
+		rq_unlock(busiest, &rf);
+
+		if (cur_ld_moved) {
+			attach_tasks(&env);
+			ld_moved += cur_ld_moved;
+		}
+
+		local_irq_restore(rf.flags);
+
+		if (env.flags & LBF_NEED_BREAK) {
+			env.flags &= ~LBF_NEED_BREAK;
+			/* Stop if we tried all running tasks */
+			if (env.loop < busiest->nr_running)
+				goto more_balance;
+		}
+
+		/*
+		 * Revisit (affine) tasks on src_cpu that couldn't be moved to
+		 * us and move them to an alternate dst_cpu in our sched_group
+		 * where they can run. The upper limit on how many times we
+		 * iterate on same src_cpu is dependent on number of CPUs in our
+		 * sched_group.
+		 *
+		 * This changes load balance semantics a bit on who can move
+		 * load to a given_cpu. In addition to the given_cpu itself
+		 * (or a ilb_cpu acting on its behalf where given_cpu is
+		 * nohz-idle), we now have balance_cpu in a position to move
+		 * load to given_cpu. In rare situations, this may cause
+		 * conflicts (balance_cpu and given_cpu/ilb_cpu deciding
+		 * _independently_ and at _same_ time to move some load to
+		 * given_cpu) causing excess load to be moved to given_cpu.
+		 * This however should not happen so much in practice and
+		 * moreover subsequent load balance cycles should correct the
+		 * excess load moved.
+		 */
+		if ((env.flags & LBF_DST_PINNED) && env.imbalance > 0) {
+
+			/* Prevent to re-select dst_cpu via env's CPUs */
+			__cpumask_clear_cpu(env.dst_cpu, env.cpus);
+
+			env.dst_rq	 = cpu_rq(env.new_dst_cpu);
+			env.dst_cpu	 = env.new_dst_cpu;
+			env.flags	&= ~LBF_DST_PINNED;
+			env.loop	 = 0;
+			env.loop_break	 = SCHED_NR_MIGRATE_BREAK;
+
+			/*
+			 * Go back to "more_balance" rather than "redo" since we
+			 * need to continue with same src_cpu.
+			 */
+			goto more_balance;
+		}
+
+		/*
+		 * We failed to reach balance because of affinity.
+		 */
+		if (sd_parent) {
+			int *group_imbalance = &sd_parent->groups->sgc->imbalance;
+
+			if ((env.flags & LBF_SOME_PINNED) && env.imbalance > 0)
+				*group_imbalance = 1;
+		}
+
+		/* All tasks on this runqueue were pinned by CPU affinity */
+		if (unlikely(env.flags & LBF_ALL_PINNED)) {
+			__cpumask_clear_cpu(cpu_of(busiest), cpus);
+			/*
+			 * Attempting to continue load balancing at the current
+			 * sched_domain level only makes sense if there are
+			 * active CPUs remaining as possible busiest CPUs to
+			 * pull load from which are not contained within the
+			 * destination group that is receiving any migrated
+			 * load.
+			 */
+			if (!cpumask_subset(cpus, env.dst_grpmask)) {
+				env.loop = 0;
+				env.loop_break = SCHED_NR_MIGRATE_BREAK;
+				goto redo;
+			}
+			goto out_all_pinned;
+		}
+	}
+
+	if (!ld_moved) {
+		schedstat_inc(sd->lb_failed[idle]);
+		/*
+		 * Increment the failure counter only on periodic balance.
+		 * We do not want newidle balance, which can be very
+		 * frequent, pollute the failure counter causing
+		 * excessive cache_hot migrations and active balances.
+		 */
+		if (idle != CPU_NEWLY_IDLE)
+			sd->nr_balance_failed++;
+
+		if (need_active_balance(&env)) {
+			unsigned long flags;
+
+			raw_spin_rq_lock_irqsave(busiest, flags);
+
+			/*
+			 * Don't kick the active_load_balance_cpu_stop,
+			 * if the curr task on busiest CPU can't be
+			 * moved to this_cpu:
+			 */
+			if (!cpumask_test_cpu(this_cpu, busiest->curr->cpus_ptr)) {
+				raw_spin_rq_unlock_irqrestore(busiest, flags);
+				goto out_one_pinned;
+			}
+
+			/* Record that we found at least one task that could run on this_cpu */
+			env.flags &= ~LBF_ALL_PINNED;
+
+			/*
+			 * ->active_balance synchronizes accesses to
+			 * ->active_balance_work.  Once set, it's cleared
+			 * only after active load balance is finished.
+			 */
+			if (!busiest->active_balance) {
+				busiest->active_balance = 1;
+				busiest->push_cpu = this_cpu;
+				active_balance = 1;
+			}
+
+			preempt_disable();
+			raw_spin_rq_unlock_irqrestore(busiest, flags);
+			if (active_balance) {
+				stop_one_cpu_nowait(cpu_of(busiest),
+					active_load_balance_cpu_stop, busiest,
+					&busiest->active_balance_work);
+			}
+			preempt_enable();
+		}
+	} else {
+		sd->nr_balance_failed = 0;
+	}
+
+	if (likely(!active_balance) || need_active_balance(&env)) {
+		/* We were unbalanced, so reset the balancing interval */
+		sd->balance_interval = sd->min_interval;
+	}
+
+	goto out;
+
+out_balanced:
+	/*
+	 * We reach balance although we may have faced some affinity
+	 * constraints. Clear the imbalance flag only if other tasks got
+	 * a chance to move and fix the imbalance.
+	 */
+	if (sd_parent && !(env.flags & LBF_ALL_PINNED)) {
+		int *group_imbalance = &sd_parent->groups->sgc->imbalance;
+
+		if (*group_imbalance)
+			*group_imbalance = 0;
+	}
+
+out_all_pinned:
+	/*
+	 * We reach balance because all tasks are pinned at this level so
+	 * we can't migrate them. Let the imbalance flag set so parent level
+	 * can try to migrate them.
+	 */
+	schedstat_inc(sd->lb_balanced[idle]);
+
+	sd->nr_balance_failed = 0;
+
+out_one_pinned:
+	ld_moved = 0;
+
+	/*
+	 * newidle_balance() disregards balance intervals, so we could
+	 * repeatedly reach this code, which would lead to balance_interval
+	 * skyrocketing in a short amount of time. Skip the balance_interval
+	 * increase logic to avoid that.
+	 */
+	if (env.idle == CPU_NEWLY_IDLE)
+		goto out;
+
+	/* tune up the balancing interval */
+	if ((env.flags & LBF_ALL_PINNED &&
+	     sd->balance_interval < MAX_PINNED_INTERVAL) ||
+	    sd->balance_interval < sd->max_interval)
+		sd->balance_interval *= 2;
+out:
+	return ld_moved;
+}
+
+static inline unsigned long
+get_sd_balance_interval(struct sched_domain *sd, int cpu_busy)
+{
+	unsigned long interval = sd->balance_interval;
+
+	if (cpu_busy)
+		interval *= sd->busy_factor;
+
+	/* scale ms to jiffies */
+	interval = msecs_to_jiffies(interval);
+
+	/*
+	 * Reduce likelihood of busy balancing at higher domains racing with
+	 * balancing at lower domains by preventing their balancing periods
+	 * from being multiples of each other.
+	 */
+	if (cpu_busy)
+		interval -= 1;
+
+	interval = clamp(interval, 1UL, max_load_balance_interval);
+
+	return interval;
+}
+
+static inline void
+update_next_balance(struct sched_domain *sd, unsigned long *next_balance)
+{
+	unsigned long interval, next;
+
+	/* used by idle balance, so cpu_busy = 0 */
+	interval = get_sd_balance_interval(sd, 0);
+	next = sd->last_balance + interval;
+
+	if (time_after(*next_balance, next))
+		*next_balance = next;
+}
+
+/*
+ * active_load_balance_cpu_stop is run by the CPU stopper. It pushes
+ * running tasks off the busiest CPU onto idle CPUs. It requires at
+ * least 1 task to be running on each physical CPU where possible, and
+ * avoids physical / logical imbalances.
+ */
+static int active_load_balance_cpu_stop(void *data)
+{
+	struct rq *busiest_rq = data;
+	int busiest_cpu = cpu_of(busiest_rq);
+	int target_cpu = busiest_rq->push_cpu;
+	struct rq *target_rq = cpu_rq(target_cpu);
+	struct sched_domain *sd;
+	struct task_struct *p = NULL;
+	struct rq_flags rf;
+
+	rq_lock_irq(busiest_rq, &rf);
+	/*
+	 * Between queueing the stop-work and running it is a hole in which
+	 * CPUs can become inactive. We should not move tasks from or to
+	 * inactive CPUs.
+	 */
+	if (!cpu_active(busiest_cpu) || !cpu_active(target_cpu))
+		goto out_unlock;
+
+	/* Make sure the requested CPU hasn't gone down in the meantime: */
+	if (unlikely(busiest_cpu != smp_processor_id() ||
+		     !busiest_rq->active_balance))
+		goto out_unlock;
+
+	/* Is there any task to move? */
+	if (busiest_rq->nr_running <= 1)
+		goto out_unlock;
+
+	/*
+	 * This condition is "impossible", if it occurs
+	 * we need to fix it. Originally reported by
+	 * Bjorn Helgaas on a 128-CPU setup.
+	 */
+	WARN_ON_ONCE(busiest_rq == target_rq);
+
+	/* Search for an sd spanning us and the target CPU. */
+	rcu_read_lock();
+	for_each_domain(target_cpu, sd) {
+		if (cpumask_test_cpu(busiest_cpu, sched_domain_span(sd)))
+			break;
+	}
+
+	if (likely(sd)) {
+		struct lb_env env = {
+			.sd		= sd,
+			.dst_cpu	= target_cpu,
+			.dst_rq		= target_rq,
+			.src_cpu	= busiest_rq->cpu,
+			.src_rq		= busiest_rq,
+			.idle		= CPU_IDLE,
+			.flags		= LBF_ACTIVE_LB,
+		};
+
+		schedstat_inc(sd->alb_count);
+		update_rq_clock(busiest_rq);
+
+		p = detach_one_task(&env);
+		if (p) {
+			schedstat_inc(sd->alb_pushed);
+			/* Active balancing done, reset the failure counter. */
+			sd->nr_balance_failed = 0;
+		} else {
+			schedstat_inc(sd->alb_failed);
+		}
+	}
+	rcu_read_unlock();
+out_unlock:
+	busiest_rq->active_balance = 0;
+	rq_unlock(busiest_rq, &rf);
+
+	if (p)
+		attach_one_task(target_rq, p);
+
+	local_irq_enable();
+
+	return 0;
+}
+
+static DEFINE_SPINLOCK(balancing);
+
+/*
+ * Scale the max load_balance interval with the number of CPUs in the system.
+ * This trades load-balance latency on larger machines for less cross talk.
+ */
+void update_max_interval(void)
+{
+	max_load_balance_interval = HZ*num_online_cpus()/10;
+}
+
+static inline bool update_newidle_cost(struct sched_domain *sd, u64 cost)
+{
+	if (cost > sd->max_newidle_lb_cost) {
+		/*
+		 * Track max cost of a domain to make sure to not delay the
+		 * next wakeup on the CPU.
+		 */
+		sd->max_newidle_lb_cost = cost;
+		sd->last_decay_max_lb_cost = jiffies;
+	} else if (time_after(jiffies, sd->last_decay_max_lb_cost + HZ)) {
+		/*
+		 * Decay the newidle max times by ~1% per second to ensure that
+		 * it is not outdated and the current max cost is actually
+		 * shorter.
+		 */
+		sd->max_newidle_lb_cost = (sd->max_newidle_lb_cost * 253) / 256;
+		sd->last_decay_max_lb_cost = jiffies;
+
+		return true;
+	}
+
+	return false;
+}
+
+/*
+ * It checks each scheduling domain to see if it is due to be balanced,
+ * and initiates a balancing operation if so.
+ *
+ * Balancing parameters are set up in init_sched_domains.
+ */
+static void rebalance_domains(struct rq *rq, enum cpu_idle_type idle)
+{
+	int continue_balancing = 1;
+	int cpu = rq->cpu;
+	int busy = idle != CPU_IDLE && !sched_idle_cpu(cpu);
+	unsigned long interval;
+	struct sched_domain *sd;
+	/* Earliest time when we have to do rebalance again */
+	unsigned long next_balance = jiffies + 60*HZ;
+	int update_next_balance = 0;
+	int need_serialize, need_decay = 0;
+	u64 max_cost = 0;
+
+	rcu_read_lock();
+	for_each_domain(cpu, sd) {
+		/*
+		 * Decay the newidle max times here because this is a regular
+		 * visit to all the domains.
+		 */
+		need_decay = update_newidle_cost(sd, 0);
+		max_cost += sd->max_newidle_lb_cost;
+
+		/*
+		 * Stop the load balance at this level. There is another
+		 * CPU in our sched group which is doing load balancing more
+		 * actively.
+		 */
+		if (!continue_balancing) {
+			if (need_decay)
+				continue;
+			break;
+		}
+
+		interval = get_sd_balance_interval(sd, busy);
+
+		need_serialize = sd->flags & SD_SERIALIZE;
+		if (need_serialize) {
+			if (!spin_trylock(&balancing))
+				goto out;
+		}
+
+		if (time_after_eq(jiffies, sd->last_balance + interval)) {
+			if (load_balance(cpu, rq, sd, idle, &continue_balancing)) {
+				/*
+				 * The LBF_DST_PINNED logic could have changed
+				 * env->dst_cpu, so we can't know our idle
+				 * state even if we migrated tasks. Update it.
+				 */
+				idle = idle_cpu(cpu) ? CPU_IDLE : CPU_NOT_IDLE;
+				busy = idle != CPU_IDLE && !sched_idle_cpu(cpu);
+			}
+			sd->last_balance = jiffies;
+			interval = get_sd_balance_interval(sd, busy);
+		}
+		if (need_serialize)
+			spin_unlock(&balancing);
+out:
+		if (time_after(next_balance, sd->last_balance + interval)) {
+			next_balance = sd->last_balance + interval;
+			update_next_balance = 1;
+		}
+	}
+	if (need_decay) {
+		/*
+		 * Ensure the rq-wide value also decays but keep it at a
+		 * reasonable floor to avoid funnies with rq->avg_idle.
+		 */
+		rq->max_idle_balance_cost =
+			max((u64)sysctl_sched_migration_cost, max_cost);
+	}
+	rcu_read_unlock();
+
+	/*
+	 * next_balance will be updated only when there is a need.
+	 * When the cpu is attached to null domain for ex, it will not be
+	 * updated.
+	 */
+	if (likely(update_next_balance))
+		rq->next_balance = next_balance;
+
+}
+
+static inline int on_null_domain(struct rq *rq)
+{
+	return unlikely(!rcu_dereference_sched(rq->sd));
+}
+
+#ifdef CONFIG_NO_HZ_COMMON
+/*
+ * idle load balancing details
+ * - When one of the busy CPUs notice that there may be an idle rebalancing
+ *   needed, they will kick the idle load balancer, which then does idle
+ *   load balancing for all the idle CPUs.
+ * - HK_TYPE_MISC CPUs are used for this task, because HK_TYPE_SCHED not set
+ *   anywhere yet.
+ */
+
+static inline int find_new_ilb(void)
+{
+	int ilb;
+	const struct cpumask *hk_mask;
+
+	hk_mask = housekeeping_cpumask(HK_TYPE_MISC);
+
+	for_each_cpu_and(ilb, nohz.idle_cpus_mask, hk_mask) {
+
+		if (ilb == smp_processor_id())
+			continue;
+
+		if (idle_cpu(ilb))
+			return ilb;
+	}
+
+	return nr_cpu_ids;
+}
+
+/*
+ * Kick a CPU to do the nohz balancing, if it is time for it. We pick any
+ * idle CPU in the HK_TYPE_MISC housekeeping set (if there is one).
+ */
+static void kick_ilb(unsigned int flags)
+{
+	int ilb_cpu;
+
+	/*
+	 * Increase nohz.next_balance only when if full ilb is triggered but
+	 * not if we only update stats.
+	 */
+	if (flags & NOHZ_BALANCE_KICK)
+		nohz.next_balance = jiffies+1;
+
+	ilb_cpu = find_new_ilb();
+
+	if (ilb_cpu >= nr_cpu_ids)
+		return;
+
+	/*
+	 * Access to rq::nohz_csd is serialized by NOHZ_KICK_MASK; he who sets
+	 * the first flag owns it; cleared by nohz_csd_func().
+	 */
+	flags = atomic_fetch_or(flags, nohz_flags(ilb_cpu));
+	if (flags & NOHZ_KICK_MASK)
+		return;
+
+	/*
+	 * This way we generate an IPI on the target CPU which
+	 * is idle. And the softirq performing nohz idle load balance
+	 * will be run before returning from the IPI.
+	 */
+	smp_call_function_single_async(ilb_cpu, &cpu_rq(ilb_cpu)->nohz_csd);
+}
+
+/*
+ * Current decision point for kicking the idle load balancer in the presence
+ * of idle CPUs in the system.
+ */
+static void nohz_balancer_kick(struct rq *rq)
+{
+	unsigned long now = jiffies;
+	struct sched_domain_shared *sds;
+	struct sched_domain *sd;
+	int nr_busy, i, cpu = rq->cpu;
+	unsigned int flags = 0;
+
+	if (unlikely(rq->idle_balance))
+		return;
+
+	/*
+	 * We may be recently in ticked or tickless idle mode. At the first
+	 * busy tick after returning from idle, we will update the busy stats.
+	 */
+	nohz_balance_exit_idle(rq);
+
+	/*
+	 * None are in tickless mode and hence no need for NOHZ idle load
+	 * balancing.
+	 */
+	if (likely(!atomic_read(&nohz.nr_cpus)))
+		return;
+
+	if (READ_ONCE(nohz.has_blocked) &&
+	    time_after(now, READ_ONCE(nohz.next_blocked)))
+		flags = NOHZ_STATS_KICK;
+
+	if (time_before(now, nohz.next_balance))
+		goto out;
+
+	if (rq->nr_running >= 2) {
+		flags = NOHZ_STATS_KICK | NOHZ_BALANCE_KICK;
+		goto out;
+	}
+
+	rcu_read_lock();
+
+	sd = rcu_dereference(rq->sd);
+	if (sd) {
+		/*
+		 * If there's a CFS task and the current CPU has reduced
+		 * capacity; kick the ILB to see if there's a better CPU to run
+		 * on.
+		 */
+		if (rq->cfs.h_nr_running >= 1 && check_cpu_capacity(rq, sd)) {
+			flags = NOHZ_STATS_KICK | NOHZ_BALANCE_KICK;
+			goto unlock;
+		}
+	}
+
+	sd = rcu_dereference(per_cpu(sd_asym_packing, cpu));
+	if (sd) {
+		/*
+		 * When ASYM_PACKING; see if there's a more preferred CPU
+		 * currently idle; in which case, kick the ILB to move tasks
+		 * around.
+		 *
+		 * When balancing betwen cores, all the SMT siblings of the
+		 * preferred CPU must be idle.
+		 */
+		for_each_cpu_and(i, sched_domain_span(sd), nohz.idle_cpus_mask) {
+			if (sched_use_asym_prio(sd, i) &&
+			    sched_asym_prefer(i, cpu)) {
+				flags = NOHZ_STATS_KICK | NOHZ_BALANCE_KICK;
+				goto unlock;
+			}
+		}
+	}
+
+	sd = rcu_dereference(per_cpu(sd_asym_cpucapacity, cpu));
+	if (sd) {
+		/*
+		 * When ASYM_CPUCAPACITY; see if there's a higher capacity CPU
+		 * to run the misfit task on.
+		 */
+		if (check_misfit_status(rq, sd)) {
+			flags = NOHZ_STATS_KICK | NOHZ_BALANCE_KICK;
+			goto unlock;
+		}
+
+		/*
+		 * For asymmetric systems, we do not want to nicely balance
+		 * cache use, instead we want to embrace asymmetry and only
+		 * ensure tasks have enough CPU capacity.
+		 *
+		 * Skip the LLC logic because it's not relevant in that case.
+		 */
+		goto unlock;
+	}
+
+	sds = rcu_dereference(per_cpu(sd_llc_shared, cpu));
+	if (sds) {
+		/*
+		 * If there is an imbalance between LLC domains (IOW we could
+		 * increase the overall cache use), we need some less-loaded LLC
+		 * domain to pull some load. Likewise, we may need to spread
+		 * load within the current LLC domain (e.g. packed SMT cores but
+		 * other CPUs are idle). We can't really know from here how busy
+		 * the others are - so just get a nohz balance going if it looks
+		 * like this LLC domain has tasks we could move.
+		 */
+		nr_busy = atomic_read(&sds->nr_busy_cpus);
+		if (nr_busy > 1) {
+			flags = NOHZ_STATS_KICK | NOHZ_BALANCE_KICK;
+			goto unlock;
+		}
+	}
+unlock:
+	rcu_read_unlock();
+out:
+	if (READ_ONCE(nohz.needs_update))
+		flags |= NOHZ_NEXT_KICK;
+
+	if (flags)
+		kick_ilb(flags);
+}
+
+static void set_cpu_sd_state_busy(int cpu)
+{
+	struct sched_domain *sd;
+
+	rcu_read_lock();
+	sd = rcu_dereference(per_cpu(sd_llc, cpu));
+
+	if (!sd || !sd->nohz_idle)
+		goto unlock;
+	sd->nohz_idle = 0;
+
+	atomic_inc(&sd->shared->nr_busy_cpus);
+unlock:
+	rcu_read_unlock();
+}
+
+void nohz_balance_exit_idle(struct rq *rq)
+{
+	SCHED_WARN_ON(rq != this_rq());
+
+	if (likely(!rq->nohz_tick_stopped))
+		return;
+
+	rq->nohz_tick_stopped = 0;
+	cpumask_clear_cpu(rq->cpu, nohz.idle_cpus_mask);
+	atomic_dec(&nohz.nr_cpus);
+
+	set_cpu_sd_state_busy(rq->cpu);
+}
+
+static void set_cpu_sd_state_idle(int cpu)
+{
+	struct sched_domain *sd;
+
+	rcu_read_lock();
+	sd = rcu_dereference(per_cpu(sd_llc, cpu));
+
+	if (!sd || sd->nohz_idle)
+		goto unlock;
+	sd->nohz_idle = 1;
+
+	atomic_dec(&sd->shared->nr_busy_cpus);
+unlock:
+	rcu_read_unlock();
+}
+
+/*
+ * This routine will record that the CPU is going idle with tick stopped.
+ * This info will be used in performing idle load balancing in the future.
+ */
+void nohz_balance_enter_idle(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	SCHED_WARN_ON(cpu != smp_processor_id());
+
+	/* If this CPU is going down, then nothing needs to be done: */
+	if (!cpu_active(cpu))
+		return;
+
+	/* Spare idle load balancing on CPUs that don't want to be disturbed: */
+	if (!housekeeping_cpu(cpu, HK_TYPE_SCHED))
+		return;
+
+	/*
+	 * Can be set safely without rq->lock held
+	 * If a clear happens, it will have evaluated last additions because
+	 * rq->lock is held during the check and the clear
+	 */
+	rq->has_blocked_load = 1;
+
+	/*
+	 * The tick is still stopped but load could have been added in the
+	 * meantime. We set the nohz.has_blocked flag to trig a check of the
+	 * *_avg. The CPU is already part of nohz.idle_cpus_mask so the clear
+	 * of nohz.has_blocked can only happen after checking the new load
+	 */
+	if (rq->nohz_tick_stopped)
+		goto out;
+
+	/* If we're a completely isolated CPU, we don't play: */
+	if (on_null_domain(rq))
+		return;
+
+	rq->nohz_tick_stopped = 1;
+
+	cpumask_set_cpu(cpu, nohz.idle_cpus_mask);
+	atomic_inc(&nohz.nr_cpus);
+
+	/*
+	 * Ensures that if nohz_idle_balance() fails to observe our
+	 * @idle_cpus_mask store, it must observe the @has_blocked
+	 * and @needs_update stores.
+	 */
+	smp_mb__after_atomic();
+
+	set_cpu_sd_state_idle(cpu);
+
+	WRITE_ONCE(nohz.needs_update, 1);
+out:
+	/*
+	 * Each time a cpu enter idle, we assume that it has blocked load and
+	 * enable the periodic update of the load of idle cpus
+	 */
+	WRITE_ONCE(nohz.has_blocked, 1);
+}
+
+static bool update_nohz_stats(struct rq *rq)
+{
+	unsigned int cpu = rq->cpu;
+
+	if (!rq->has_blocked_load)
+		return false;
+
+	if (!cpumask_test_cpu(cpu, nohz.idle_cpus_mask))
+		return false;
+
+	if (!time_after(jiffies, READ_ONCE(rq->last_blocked_load_update_tick)))
+		return true;
+
+	update_blocked_averages(cpu);
+
+	return rq->has_blocked_load;
+}
+
+/*
+ * Internal function that runs load balance for all idle cpus. The load balance
+ * can be a simple update of blocked load or a complete load balance with
+ * tasks movement depending of flags.
+ */
+static void _nohz_idle_balance(struct rq *this_rq, unsigned int flags)
+{
+	/* Earliest time when we have to do rebalance again */
+	unsigned long now = jiffies;
+	unsigned long next_balance = now + 60*HZ;
+	bool has_blocked_load = false;
+	int update_next_balance = 0;
+	int this_cpu = this_rq->cpu;
+	int balance_cpu;
+	struct rq *rq;
+
+	SCHED_WARN_ON((flags & NOHZ_KICK_MASK) == NOHZ_BALANCE_KICK);
+
+	/*
+	 * We assume there will be no idle load after this update and clear
+	 * the has_blocked flag. If a cpu enters idle in the mean time, it will
+	 * set the has_blocked flag and trigger another update of idle load.
+	 * Because a cpu that becomes idle, is added to idle_cpus_mask before
+	 * setting the flag, we are sure to not clear the state and not
+	 * check the load of an idle cpu.
+	 *
+	 * Same applies to idle_cpus_mask vs needs_update.
+	 */
+	if (flags & NOHZ_STATS_KICK)
+		WRITE_ONCE(nohz.has_blocked, 0);
+	if (flags & NOHZ_NEXT_KICK)
+		WRITE_ONCE(nohz.needs_update, 0);
+
+	/*
+	 * Ensures that if we miss the CPU, we must see the has_blocked
+	 * store from nohz_balance_enter_idle().
+	 */
+	smp_mb();
+
+	/*
+	 * Start with the next CPU after this_cpu so we will end with this_cpu and let a
+	 * chance for other idle cpu to pull load.
+	 */
+	for_each_cpu_wrap(balance_cpu,  nohz.idle_cpus_mask, this_cpu+1) {
+		if (!idle_cpu(balance_cpu))
+			continue;
+
+		/*
+		 * If this CPU gets work to do, stop the load balancing
+		 * work being done for other CPUs. Next load
+		 * balancing owner will pick it up.
+		 */
+		if (need_resched()) {
+			if (flags & NOHZ_STATS_KICK)
+				has_blocked_load = true;
+			if (flags & NOHZ_NEXT_KICK)
+				WRITE_ONCE(nohz.needs_update, 1);
+			goto abort;
+		}
+
+		rq = cpu_rq(balance_cpu);
+
+		if (flags & NOHZ_STATS_KICK)
+			has_blocked_load |= update_nohz_stats(rq);
+
+		/*
+		 * If time for next balance is due,
+		 * do the balance.
+		 */
+		if (time_after_eq(jiffies, rq->next_balance)) {
+			struct rq_flags rf;
+
+			rq_lock_irqsave(rq, &rf);
+			update_rq_clock(rq);
+			rq_unlock_irqrestore(rq, &rf);
+
+			if (flags & NOHZ_BALANCE_KICK)
+				rebalance_domains(rq, CPU_IDLE);
+		}
+
+		if (time_after(next_balance, rq->next_balance)) {
+			next_balance = rq->next_balance;
+			update_next_balance = 1;
+		}
+	}
+
+	/*
+	 * next_balance will be updated only when there is a need.
+	 * When the CPU is attached to null domain for ex, it will not be
+	 * updated.
+	 */
+	if (likely(update_next_balance))
+		nohz.next_balance = next_balance;
+
+	if (flags & NOHZ_STATS_KICK)
+		WRITE_ONCE(nohz.next_blocked,
+			   now + msecs_to_jiffies(LOAD_AVG_PERIOD));
+
+abort:
+	/* There is still blocked load, enable periodic update */
+	if (has_blocked_load)
+		WRITE_ONCE(nohz.has_blocked, 1);
+}
+
+/*
+ * In CONFIG_NO_HZ_COMMON case, the idle balance kickee will do the
+ * rebalancing for all the cpus for whom scheduler ticks are stopped.
+ */
+static bool nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle)
+{
+	unsigned int flags = this_rq->nohz_idle_balance;
+
+	if (!flags)
+		return false;
+
+	this_rq->nohz_idle_balance = 0;
+
+	if (idle != CPU_IDLE)
+		return false;
+
+	_nohz_idle_balance(this_rq, flags);
+
+	return true;
+}
+
+/*
+ * Check if we need to run the ILB for updating blocked load before entering
+ * idle state.
+ */
+void nohz_run_idle_balance(int cpu)
+{
+	unsigned int flags;
+
+	flags = atomic_fetch_andnot(NOHZ_NEWILB_KICK, nohz_flags(cpu));
+
+	/*
+	 * Update the blocked load only if no SCHED_SOFTIRQ is about to happen
+	 * (ie NOHZ_STATS_KICK set) and will do the same.
+	 */
+	if ((flags == NOHZ_NEWILB_KICK) && !need_resched())
+		_nohz_idle_balance(cpu_rq(cpu), NOHZ_STATS_KICK);
+}
+
+static void nohz_newidle_balance(struct rq *this_rq)
+{
+	int this_cpu = this_rq->cpu;
+
+	/*
+	 * This CPU doesn't want to be disturbed by scheduler
+	 * housekeeping
+	 */
+	if (!housekeeping_cpu(this_cpu, HK_TYPE_SCHED))
+		return;
+
+	/* Will wake up very soon. No time for doing anything else*/
+	if (this_rq->avg_idle < sysctl_sched_migration_cost)
+		return;
+
+	/* Don't need to update blocked load of idle CPUs*/
+	if (!READ_ONCE(nohz.has_blocked) ||
+	    time_before(jiffies, READ_ONCE(nohz.next_blocked)))
+		return;
+
+	/*
+	 * Set the need to trigger ILB in order to update blocked load
+	 * before entering idle state.
+	 */
+	atomic_or(NOHZ_NEWILB_KICK, nohz_flags(this_cpu));
+}
+
+#else /* !CONFIG_NO_HZ_COMMON */
+static inline void nohz_balancer_kick(struct rq *rq) { }
+
+static inline bool nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle)
+{
+	return false;
+}
+
+static inline void nohz_newidle_balance(struct rq *this_rq) { }
+#endif /* CONFIG_NO_HZ_COMMON */
+
+/*
+ * newidle_balance is called by schedule() if this_cpu is about to become
+ * idle. Attempts to pull tasks from other CPUs.
+ *
+ * Returns:
+ *   < 0 - we released the lock and there are !fair tasks present
+ *     0 - failed, no new tasks
+ *   > 0 - success, new (fair) tasks present
+ */
+static int newidle_balance(struct rq *this_rq, struct rq_flags *rf)
+{
+	unsigned long next_balance = jiffies + HZ;
+	int this_cpu = this_rq->cpu;
+	u64 t0, t1, curr_cost = 0;
+	struct sched_domain *sd;
+	int pulled_task = 0;
+
+	update_misfit_status(NULL, this_rq);
+
+	/*
+	 * There is a task waiting to run. No need to search for one.
+	 * Return 0; the task will be enqueued when switching to idle.
+	 */
+	if (this_rq->ttwu_pending)
+		return 0;
+
+	/*
+	 * We must set idle_stamp _before_ calling idle_balance(), such that we
+	 * measure the duration of idle_balance() as idle time.
+	 */
+	this_rq->idle_stamp = rq_clock(this_rq);
+
+	/*
+	 * Do not pull tasks towards !active CPUs...
+	 */
+	if (!cpu_active(this_cpu))
+		return 0;
+
+	/*
+	 * This is OK, because current is on_cpu, which avoids it being picked
+	 * for load-balance and preemption/IRQs are still disabled avoiding
+	 * further scheduler activity on it and we're being very careful to
+	 * re-start the picking loop.
+	 */
+	rq_unpin_lock(this_rq, rf);
+
+	rcu_read_lock();
+	sd = rcu_dereference_check_sched_domain(this_rq->sd);
+
+	if (!READ_ONCE(this_rq->rd->overload) ||
+	    (sd && this_rq->avg_idle < sd->max_newidle_lb_cost)) {
+
+		if (sd)
+			update_next_balance(sd, &next_balance);
+		rcu_read_unlock();
+
+		goto out;
+	}
+	rcu_read_unlock();
+
+	raw_spin_rq_unlock(this_rq);
+
+	t0 = sched_clock_cpu(this_cpu);
+	update_blocked_averages(this_cpu);
+
+	rcu_read_lock();
+	for_each_domain(this_cpu, sd) {
+		int continue_balancing = 1;
+		u64 domain_cost;
+
+		update_next_balance(sd, &next_balance);
+
+		if (this_rq->avg_idle < curr_cost + sd->max_newidle_lb_cost)
+			break;
+
+		if (sd->flags & SD_BALANCE_NEWIDLE) {
+
+			pulled_task = load_balance(this_cpu, this_rq,
+						   sd, CPU_NEWLY_IDLE,
+						   &continue_balancing);
+
+			t1 = sched_clock_cpu(this_cpu);
+			domain_cost = t1 - t0;
+			update_newidle_cost(sd, domain_cost);
+
+			curr_cost += domain_cost;
+			t0 = t1;
+		}
+
+		/*
+		 * Stop searching for tasks to pull if there are
+		 * now runnable tasks on this rq.
+		 */
+		if (pulled_task || this_rq->nr_running > 0 ||
+		    this_rq->ttwu_pending)
+			break;
+	}
+	rcu_read_unlock();
+
+	raw_spin_rq_lock(this_rq);
+
+	if (curr_cost > this_rq->max_idle_balance_cost)
+		this_rq->max_idle_balance_cost = curr_cost;
+
+	/*
+	 * While browsing the domains, we released the rq lock, a task could
+	 * have been enqueued in the meantime. Since we're not going idle,
+	 * pretend we pulled a task.
+	 */
+	if (this_rq->cfs.h_nr_running && !pulled_task)
+		pulled_task = 1;
+
+	/* Is there a task of a high priority class? */
+	if (this_rq->nr_running != this_rq->cfs.h_nr_running)
+		pulled_task = -1;
+
+out:
+	/* Move the next balance forward */
+	if (time_after(this_rq->next_balance, next_balance))
+		this_rq->next_balance = next_balance;
+
+	if (pulled_task)
+		this_rq->idle_stamp = 0;
+	else
+		nohz_newidle_balance(this_rq);
+
+	rq_repin_lock(this_rq, rf);
+
+	return pulled_task;
+}
+
+/*
+ * run_rebalance_domains is triggered when needed from the scheduler tick.
+ * Also triggered for nohz idle balancing (with nohz_balancing_kick set).
+ */
+static __latent_entropy void run_rebalance_domains(struct softirq_action *h)
+{
+	struct rq *this_rq = this_rq();
+	enum cpu_idle_type idle = this_rq->idle_balance ?
+						CPU_IDLE : CPU_NOT_IDLE;
+
+	/*
+	 * If this CPU has a pending nohz_balance_kick, then do the
+	 * balancing on behalf of the other idle CPUs whose ticks are
+	 * stopped. Do nohz_idle_balance *before* rebalance_domains to
+	 * give the idle CPUs a chance to load balance. Else we may
+	 * load balance only within the local sched_domain hierarchy
+	 * and abort nohz_idle_balance altogether if we pull some load.
+	 */
+	if (nohz_idle_balance(this_rq, idle))
+		return;
+
+	/* normal load balance */
+	update_blocked_averages(this_rq->cpu);
+	rebalance_domains(this_rq, idle);
+}
+
+/*
+ * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
+ */
+void trigger_load_balance(struct rq *rq)
+{
+	/*
+	 * Don't need to rebalance while attached to NULL domain or
+	 * runqueue CPU is not active
+	 */
+	if (unlikely(on_null_domain(rq) || !cpu_active(cpu_of(rq))))
+		return;
+
+	if (time_after_eq(jiffies, rq->next_balance))
+		raise_softirq(SCHED_SOFTIRQ);
+
+	nohz_balancer_kick(rq);
+}
+
+static void rq_online_fair(struct rq *rq)
+{
+	update_sysctl();
+
+	update_runtime_enabled(rq);
+}
+
+static void rq_offline_fair(struct rq *rq)
+{
+	update_sysctl();
+
+	/* Ensure any throttled groups are reachable by pick_next_task */
+	unthrottle_offline_cfs_rqs(rq);
+}
+
+#endif /* CONFIG_SMP */
+
+#ifdef CONFIG_SCHED_CORE
+static inline bool
+__entity_slice_used(struct sched_entity *se, int min_nr_tasks)
+{
+	u64 rtime = se->sum_exec_runtime - se->prev_sum_exec_runtime;
+	u64 slice = se->slice;
+
+	return (rtime * min_nr_tasks > slice);
+}
+
+#define MIN_NR_TASKS_DURING_FORCEIDLE	2
+static inline void task_tick_core(struct rq *rq, struct task_struct *curr)
+{
+	if (!sched_core_enabled(rq))
+		return;
+
+	/*
+	 * If runqueue has only one task which used up its slice and
+	 * if the sibling is forced idle, then trigger schedule to
+	 * give forced idle task a chance.
+	 *
+	 * sched_slice() considers only this active rq and it gets the
+	 * whole slice. But during force idle, we have siblings acting
+	 * like a single runqueue and hence we need to consider runnable
+	 * tasks on this CPU and the forced idle CPU. Ideally, we should
+	 * go through the forced idle rq, but that would be a perf hit.
+	 * We can assume that the forced idle CPU has at least
+	 * MIN_NR_TASKS_DURING_FORCEIDLE - 1 tasks and use that to check
+	 * if we need to give up the CPU.
+	 */
+	if (rq->core->core_forceidle_count && rq->cfs.nr_running == 1 &&
+	    __entity_slice_used(&curr->se, MIN_NR_TASKS_DURING_FORCEIDLE))
+		resched_curr(rq);
+}
+
+/*
+ * se_fi_update - Update the cfs_rq->min_vruntime_fi in a CFS hierarchy if needed.
+ */
+static void se_fi_update(const struct sched_entity *se, unsigned int fi_seq,
+			 bool forceidle)
+{
+	for_each_sched_entity(se) {
+		struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+		if (forceidle) {
+			if (cfs_rq->forceidle_seq == fi_seq)
+				break;
+			cfs_rq->forceidle_seq = fi_seq;
+		}
+
+		cfs_rq->min_vruntime_fi = cfs_rq->min_vruntime;
+	}
+}
+
+void task_vruntime_update(struct rq *rq, struct task_struct *p, bool in_fi)
+{
+	struct sched_entity *se = &p->se;
+
+	if (p->sched_class != &fair_sched_class)
+		return;
+
+	se_fi_update(se, rq->core->core_forceidle_seq, in_fi);
+}
+
+bool cfs_prio_less(const struct task_struct *a, const struct task_struct *b,
+			bool in_fi)
+{
+	struct rq *rq = task_rq(a);
+	const struct sched_entity *sea = &a->se;
+	const struct sched_entity *seb = &b->se;
+	struct cfs_rq *cfs_rqa;
+	struct cfs_rq *cfs_rqb;
+	s64 delta;
+
+	SCHED_WARN_ON(task_rq(b)->core != rq->core);
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	/*
+	 * Find an se in the hierarchy for tasks a and b, such that the se's
+	 * are immediate siblings.
+	 */
+	while (sea->cfs_rq->tg != seb->cfs_rq->tg) {
+		int sea_depth = sea->depth;
+		int seb_depth = seb->depth;
+
+		if (sea_depth >= seb_depth)
+			sea = parent_entity(sea);
+		if (sea_depth <= seb_depth)
+			seb = parent_entity(seb);
+	}
+
+	se_fi_update(sea, rq->core->core_forceidle_seq, in_fi);
+	se_fi_update(seb, rq->core->core_forceidle_seq, in_fi);
+
+	cfs_rqa = sea->cfs_rq;
+	cfs_rqb = seb->cfs_rq;
+#else
+	cfs_rqa = &task_rq(a)->cfs;
+	cfs_rqb = &task_rq(b)->cfs;
+#endif
+
+	/*
+	 * Find delta after normalizing se's vruntime with its cfs_rq's
+	 * min_vruntime_fi, which would have been updated in prior calls
+	 * to se_fi_update().
+	 */
+	delta = (s64)(sea->vruntime - seb->vruntime) +
+		(s64)(cfs_rqb->min_vruntime_fi - cfs_rqa->min_vruntime_fi);
+
+	return delta > 0;
+}
+
+static int task_is_throttled_fair(struct task_struct *p, int cpu)
+{
+	struct cfs_rq *cfs_rq;
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	cfs_rq = task_group(p)->cfs_rq[cpu];
+#else
+	cfs_rq = &cpu_rq(cpu)->cfs;
+#endif
+	return throttled_hierarchy(cfs_rq);
+}
+#else
+static inline void task_tick_core(struct rq *rq, struct task_struct *curr) {}
+#endif
+
+/*
+ * scheduler tick hitting a task of our scheduling class.
+ *
+ * NOTE: This function can be called remotely by the tick offload that
+ * goes along full dynticks. Therefore no local assumption can be made
+ * and everything must be accessed through the @rq and @curr passed in
+ * parameters.
+ */
+static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued)
+{
+	struct cfs_rq *cfs_rq;
+	struct sched_entity *se = &curr->se;
+
+	for_each_sched_entity(se) {
+		cfs_rq = cfs_rq_of(se);
+		entity_tick(cfs_rq, se, queued);
+	}
+
+	if (static_branch_unlikely(&sched_numa_balancing))
+		task_tick_numa(rq, curr);
+
+	update_misfit_status(curr, rq);
+	update_overutilized_status(task_rq(curr));
+
+	task_tick_core(rq, curr);
+}
+
+/*
+ * called on fork with the child task as argument from the parent's context
+ *  - child not yet on the tasklist
+ *  - preemption disabled
+ */
+static void task_fork_fair(struct task_struct *p)
+{
+	struct sched_entity *se = &p->se, *curr;
+	struct cfs_rq *cfs_rq;
+	struct rq *rq = this_rq();
+	struct rq_flags rf;
+
+	rq_lock(rq, &rf);
+	update_rq_clock(rq);
+
+	cfs_rq = task_cfs_rq(current);
+	curr = cfs_rq->curr;
+	if (curr)
+		update_curr(cfs_rq);
+	place_entity(cfs_rq, se, ENQUEUE_INITIAL);
+	rq_unlock(rq, &rf);
+}
+
+/*
+ * Priority of the task has changed. Check to see if we preempt
+ * the current task.
+ */
+static void
+prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio)
+{
+	if (!task_on_rq_queued(p))
+		return;
+
+	if (rq->cfs.nr_running == 1)
+		return;
+
+	/*
+	 * Reschedule if we are currently running on this runqueue and
+	 * our priority decreased, or if we are not currently running on
+	 * this runqueue and our priority is higher than the current's
+	 */
+	if (task_current(rq, p)) {
+		if (p->prio > oldprio)
+			resched_curr(rq);
+	} else
+		check_preempt_curr(rq, p, 0);
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+/*
+ * Propagate the changes of the sched_entity across the tg tree to make it
+ * visible to the root
+ */
+static void propagate_entity_cfs_rq(struct sched_entity *se)
+{
+	struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+	if (cfs_rq_throttled(cfs_rq))
+		return;
+
+	if (!throttled_hierarchy(cfs_rq))
+		list_add_leaf_cfs_rq(cfs_rq);
+
+	/* Start to propagate at parent */
+	se = se->parent;
+
+	for_each_sched_entity(se) {
+		cfs_rq = cfs_rq_of(se);
+
+		update_load_avg(cfs_rq, se, UPDATE_TG);
+
+		if (cfs_rq_throttled(cfs_rq))
+			break;
+
+		if (!throttled_hierarchy(cfs_rq))
+			list_add_leaf_cfs_rq(cfs_rq);
+	}
+}
+#else
+static void propagate_entity_cfs_rq(struct sched_entity *se) { }
+#endif
+
+static void detach_entity_cfs_rq(struct sched_entity *se)
+{
+	struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+#ifdef CONFIG_SMP
+	/*
+	 * In case the task sched_avg hasn't been attached:
+	 * - A forked task which hasn't been woken up by wake_up_new_task().
+	 * - A task which has been woken up by try_to_wake_up() but is
+	 *   waiting for actually being woken up by sched_ttwu_pending().
+	 */
+	if (!se->avg.last_update_time)
+		return;
+#endif
+
+	/* Catch up with the cfs_rq and remove our load when we leave */
+	update_load_avg(cfs_rq, se, 0);
+	detach_entity_load_avg(cfs_rq, se);
+	update_tg_load_avg(cfs_rq);
+	propagate_entity_cfs_rq(se);
+}
+
+static void attach_entity_cfs_rq(struct sched_entity *se)
+{
+	struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+	/* Synchronize entity with its cfs_rq */
+	update_load_avg(cfs_rq, se, sched_feat(ATTACH_AGE_LOAD) ? 0 : SKIP_AGE_LOAD);
+	attach_entity_load_avg(cfs_rq, se);
+	update_tg_load_avg(cfs_rq);
+	propagate_entity_cfs_rq(se);
+}
+
+static void detach_task_cfs_rq(struct task_struct *p)
+{
+	struct sched_entity *se = &p->se;
+
+	detach_entity_cfs_rq(se);
+}
+
+static void attach_task_cfs_rq(struct task_struct *p)
+{
+	struct sched_entity *se = &p->se;
+
+	attach_entity_cfs_rq(se);
+}
+
+static void switched_from_fair(struct rq *rq, struct task_struct *p)
+{
+	detach_task_cfs_rq(p);
+}
+
+static void switched_to_fair(struct rq *rq, struct task_struct *p)
+{
+	attach_task_cfs_rq(p);
+
+	if (task_on_rq_queued(p)) {
+		/*
+		 * We were most likely switched from sched_rt, so
+		 * kick off the schedule if running, otherwise just see
+		 * if we can still preempt the current task.
+		 */
+		if (task_current(rq, p))
+			resched_curr(rq);
+		else
+			check_preempt_curr(rq, p, 0);
+	}
+}
+
+/* Account for a task changing its policy or group.
+ *
+ * This routine is mostly called to set cfs_rq->curr field when a task
+ * migrates between groups/classes.
+ */
+static void set_next_task_fair(struct rq *rq, struct task_struct *p, bool first)
+{
+	struct sched_entity *se = &p->se;
+
+#ifdef CONFIG_SMP
+	if (task_on_rq_queued(p)) {
+		/*
+		 * Move the next running task to the front of the list, so our
+		 * cfs_tasks list becomes MRU one.
+		 */
+		list_move(&se->group_node, &rq->cfs_tasks);
+	}
+#endif
+
+	for_each_sched_entity(se) {
+		struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+		set_next_entity(cfs_rq, se);
+		/* ensure bandwidth has been allocated on our new cfs_rq */
+		account_cfs_rq_runtime(cfs_rq, 0);
+	}
+}
+
+void init_cfs_rq(struct cfs_rq *cfs_rq)
+{
+	cfs_rq->tasks_timeline = RB_ROOT_CACHED;
+	u64_u32_store(cfs_rq->min_vruntime, (u64)(-(1LL << 20)));
+#ifdef CONFIG_SMP
+	raw_spin_lock_init(&cfs_rq->removed.lock);
+#endif
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static void task_change_group_fair(struct task_struct *p)
+{
+	/*
+	 * We couldn't detach or attach a forked task which
+	 * hasn't been woken up by wake_up_new_task().
+	 */
+	if (READ_ONCE(p->__state) == TASK_NEW)
+		return;
+
+	detach_task_cfs_rq(p);
+
+#ifdef CONFIG_SMP
+	/* Tell se's cfs_rq has been changed -- migrated */
+	p->se.avg.last_update_time = 0;
+#endif
+	set_task_rq(p, task_cpu(p));
+	attach_task_cfs_rq(p);
+}
+
+void free_fair_sched_group(struct task_group *tg)
+{
+	int i;
+
+	for_each_possible_cpu(i) {
+		if (tg->cfs_rq)
+			kfree(tg->cfs_rq[i]);
+		if (tg->se)
+			kfree(tg->se[i]);
+	}
+
+	kfree(tg->cfs_rq);
+	kfree(tg->se);
+}
+
+int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
+{
+	struct sched_entity *se;
+	struct cfs_rq *cfs_rq;
+	int i;
+
+	tg->cfs_rq = kcalloc(nr_cpu_ids, sizeof(cfs_rq), GFP_KERNEL);
+	if (!tg->cfs_rq)
+		goto err;
+	tg->se = kcalloc(nr_cpu_ids, sizeof(se), GFP_KERNEL);
+	if (!tg->se)
+		goto err;
+
+	tg->shares = NICE_0_LOAD;
+
+	init_cfs_bandwidth(tg_cfs_bandwidth(tg), tg_cfs_bandwidth(parent));
+
+	for_each_possible_cpu(i) {
+		cfs_rq = kzalloc_node(sizeof(struct cfs_rq),
+				      GFP_KERNEL, cpu_to_node(i));
+		if (!cfs_rq)
+			goto err;
+
+		se = kzalloc_node(sizeof(struct sched_entity_stats),
+				  GFP_KERNEL, cpu_to_node(i));
+		if (!se)
+			goto err_free_rq;
+
+		init_cfs_rq(cfs_rq);
+		init_tg_cfs_entry(tg, cfs_rq, se, i, parent->se[i]);
+		init_entity_runnable_average(se);
+	}
+
+	return 1;
+
+err_free_rq:
+	kfree(cfs_rq);
+err:
+	return 0;
+}
+
+void online_fair_sched_group(struct task_group *tg)
+{
+	struct sched_entity *se;
+	struct rq_flags rf;
+	struct rq *rq;
+	int i;
+
+	for_each_possible_cpu(i) {
+		rq = cpu_rq(i);
+		se = tg->se[i];
+		rq_lock_irq(rq, &rf);
+		update_rq_clock(rq);
+		attach_entity_cfs_rq(se);
+		sync_throttle(tg, i);
+		rq_unlock_irq(rq, &rf);
+	}
+}
+
+void unregister_fair_sched_group(struct task_group *tg)
+{
+	unsigned long flags;
+	struct rq *rq;
+	int cpu;
+
+	destroy_cfs_bandwidth(tg_cfs_bandwidth(tg));
+
+	for_each_possible_cpu(cpu) {
+		if (tg->se[cpu])
+			remove_entity_load_avg(tg->se[cpu]);
+
+		/*
+		 * Only empty task groups can be destroyed; so we can speculatively
+		 * check on_list without danger of it being re-added.
+		 */
+		if (!tg->cfs_rq[cpu]->on_list)
+			continue;
+
+		rq = cpu_rq(cpu);
+
+		raw_spin_rq_lock_irqsave(rq, flags);
+		list_del_leaf_cfs_rq(tg->cfs_rq[cpu]);
+		raw_spin_rq_unlock_irqrestore(rq, flags);
+	}
+}
+
+void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
+			struct sched_entity *se, int cpu,
+			struct sched_entity *parent)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	cfs_rq->tg = tg;
+	cfs_rq->rq = rq;
+	init_cfs_rq_runtime(cfs_rq);
+
+	tg->cfs_rq[cpu] = cfs_rq;
+	tg->se[cpu] = se;
+
+	/* se could be NULL for root_task_group */
+	if (!se)
+		return;
+
+	if (!parent) {
+		se->cfs_rq = &rq->cfs;
+		se->depth = 0;
+	} else {
+		se->cfs_rq = parent->my_q;
+		se->depth = parent->depth + 1;
+	}
+
+	se->my_q = cfs_rq;
+	/* guarantee group entities always have weight */
+	update_load_set(&se->load, NICE_0_LOAD);
+	se->parent = parent;
+}
+
+static DEFINE_MUTEX(shares_mutex);
+
+static int __sched_group_set_shares(struct task_group *tg, unsigned long shares)
+{
+	int i;
+
+	lockdep_assert_held(&shares_mutex);
+
+	/*
+	 * We can't change the weight of the root cgroup.
+	 */
+	if (!tg->se[0])
+		return -EINVAL;
+
+	shares = clamp(shares, scale_load(MIN_SHARES), scale_load(MAX_SHARES));
+
+	if (tg->shares == shares)
+		return 0;
+
+	tg->shares = shares;
+	for_each_possible_cpu(i) {
+		struct rq *rq = cpu_rq(i);
+		struct sched_entity *se = tg->se[i];
+		struct rq_flags rf;
+
+		/* Propagate contribution to hierarchy */
+		rq_lock_irqsave(rq, &rf);
+		update_rq_clock(rq);
+		for_each_sched_entity(se) {
+			update_load_avg(cfs_rq_of(se), se, UPDATE_TG);
+			update_cfs_group(se);
+		}
+		rq_unlock_irqrestore(rq, &rf);
+	}
+
+	return 0;
+}
+
+int sched_group_set_shares(struct task_group *tg, unsigned long shares)
+{
+	int ret;
+
+	mutex_lock(&shares_mutex);
+	if (tg_is_idle(tg))
+		ret = -EINVAL;
+	else
+		ret = __sched_group_set_shares(tg, shares);
+	mutex_unlock(&shares_mutex);
+
+	return ret;
+}
+
+int sched_group_set_idle(struct task_group *tg, long idle)
+{
+	int i;
+
+	if (tg == &root_task_group)
+		return -EINVAL;
+
+	if (idle < 0 || idle > 1)
+		return -EINVAL;
+
+	mutex_lock(&shares_mutex);
+
+	if (tg->idle == idle) {
+		mutex_unlock(&shares_mutex);
+		return 0;
+	}
+
+	tg->idle = idle;
+
+	for_each_possible_cpu(i) {
+		struct rq *rq = cpu_rq(i);
+		struct sched_entity *se = tg->se[i];
+		struct cfs_rq *parent_cfs_rq, *grp_cfs_rq = tg->cfs_rq[i];
+		bool was_idle = cfs_rq_is_idle(grp_cfs_rq);
+		long idle_task_delta;
+		struct rq_flags rf;
+
+		rq_lock_irqsave(rq, &rf);
+
+		grp_cfs_rq->idle = idle;
+		if (WARN_ON_ONCE(was_idle == cfs_rq_is_idle(grp_cfs_rq)))
+			goto next_cpu;
+
+		if (se->on_rq) {
+			parent_cfs_rq = cfs_rq_of(se);
+			if (cfs_rq_is_idle(grp_cfs_rq))
+				parent_cfs_rq->idle_nr_running++;
+			else
+				parent_cfs_rq->idle_nr_running--;
+		}
+
+		idle_task_delta = grp_cfs_rq->h_nr_running -
+				  grp_cfs_rq->idle_h_nr_running;
+		if (!cfs_rq_is_idle(grp_cfs_rq))
+			idle_task_delta *= -1;
+
+		for_each_sched_entity(se) {
+			struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+			if (!se->on_rq)
+				break;
+
+			cfs_rq->idle_h_nr_running += idle_task_delta;
+
+			/* Already accounted at parent level and above. */
+			if (cfs_rq_is_idle(cfs_rq))
+				break;
+		}
+
+next_cpu:
+		rq_unlock_irqrestore(rq, &rf);
+	}
+
+	/* Idle groups have minimum weight. */
+	if (tg_is_idle(tg))
+		__sched_group_set_shares(tg, scale_load(WEIGHT_IDLEPRIO));
+	else
+		__sched_group_set_shares(tg, NICE_0_LOAD);
+
+	mutex_unlock(&shares_mutex);
+	return 0;
+}
+
+#else /* CONFIG_FAIR_GROUP_SCHED */
+
+void free_fair_sched_group(struct task_group *tg) { }
+
+int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
+{
+	return 1;
+}
+
+void online_fair_sched_group(struct task_group *tg) { }
+
+void unregister_fair_sched_group(struct task_group *tg) { }
+
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+
+static unsigned int get_rr_interval_fair(struct rq *rq, struct task_struct *task)
+{
+	struct sched_entity *se = &task->se;
+	unsigned int rr_interval = 0;
+
+	/*
+	 * Time slice is 0 for SCHED_OTHER tasks that are on an otherwise
+	 * idle runqueue:
+	 */
+	if (rq->cfs.load.weight)
+		rr_interval = NS_TO_JIFFIES(se->slice);
+
+	return rr_interval;
+}
+
+/*
+ * All the scheduling class methods:
+ */
+DEFINE_SCHED_CLASS(fair) = {
+
+	.enqueue_task		= enqueue_task_fair,
+	.dequeue_task		= dequeue_task_fair,
+	.yield_task		= yield_task_fair,
+	.yield_to_task		= yield_to_task_fair,
+
+	.check_preempt_curr	= check_preempt_wakeup,
+
+	.pick_next_task		= __pick_next_task_fair,
+	.put_prev_task		= put_prev_task_fair,
+	.set_next_task          = set_next_task_fair,
+
+#ifdef CONFIG_SMP
+	.balance		= balance_fair,
+	.pick_task		= pick_task_fair,
+	.select_task_rq		= select_task_rq_fair,
+	.migrate_task_rq	= migrate_task_rq_fair,
+
+	.rq_online		= rq_online_fair,
+	.rq_offline		= rq_offline_fair,
+
+	.task_dead		= task_dead_fair,
+	.set_cpus_allowed	= set_cpus_allowed_common,
+#endif
+
+	.task_tick		= task_tick_fair,
+	.task_fork		= task_fork_fair,
+
+	.prio_changed		= prio_changed_fair,
+	.switched_from		= switched_from_fair,
+	.switched_to		= switched_to_fair,
+
+	.get_rr_interval	= get_rr_interval_fair,
+
+	.update_curr		= update_curr_fair,
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	.task_change_group	= task_change_group_fair,
+#endif
+
+#ifdef CONFIG_SCHED_CORE
+	.task_is_throttled	= task_is_throttled_fair,
+#endif
+
+#ifdef CONFIG_UCLAMP_TASK
+	.uclamp_enabled		= 1,
+#endif
+};
+
+#ifdef CONFIG_SCHED_DEBUG
+void print_cfs_stats(struct seq_file *m, int cpu)
+{
+	struct cfs_rq *cfs_rq, *pos;
+
+	rcu_read_lock();
+	for_each_leaf_cfs_rq_safe(cpu_rq(cpu), cfs_rq, pos)
+		print_cfs_rq(m, cpu, cfs_rq);
+	rcu_read_unlock();
+}
+
+#ifdef CONFIG_NUMA_BALANCING
+void show_numa_stats(struct task_struct *p, struct seq_file *m)
+{
+	int node;
+	unsigned long tsf = 0, tpf = 0, gsf = 0, gpf = 0;
+	struct numa_group *ng;
+
+	rcu_read_lock();
+	ng = rcu_dereference(p->numa_group);
+	for_each_online_node(node) {
+		if (p->numa_faults) {
+			tsf = p->numa_faults[task_faults_idx(NUMA_MEM, node, 0)];
+			tpf = p->numa_faults[task_faults_idx(NUMA_MEM, node, 1)];
+		}
+		if (ng) {
+			gsf = ng->faults[task_faults_idx(NUMA_MEM, node, 0)],
+			gpf = ng->faults[task_faults_idx(NUMA_MEM, node, 1)];
+		}
+		print_numa_stats(m, node, tsf, tpf, gsf, gpf);
+	}
+	rcu_read_unlock();
+}
+#endif /* CONFIG_NUMA_BALANCING */
+#endif /* CONFIG_SCHED_DEBUG */
+
+__init void init_sched_fair_class(void)
+{
+#ifdef CONFIG_SMP
+	int i;
+
+	for_each_possible_cpu(i) {
+		zalloc_cpumask_var_node(&per_cpu(load_balance_mask, i), GFP_KERNEL, cpu_to_node(i));
+		zalloc_cpumask_var_node(&per_cpu(select_rq_mask,    i), GFP_KERNEL, cpu_to_node(i));
+		zalloc_cpumask_var_node(&per_cpu(should_we_balance_tmpmask, i),
+					GFP_KERNEL, cpu_to_node(i));
+
+#ifdef CONFIG_CFS_BANDWIDTH
+		INIT_CSD(&cpu_rq(i)->cfsb_csd, __cfsb_csd_unthrottle, cpu_rq(i));
+		INIT_LIST_HEAD(&cpu_rq(i)->cfsb_csd_list);
+#endif
+	}
+
+	open_softirq(SCHED_SOFTIRQ, run_rebalance_domains);
+
+#ifdef CONFIG_NO_HZ_COMMON
+	nohz.next_balance = jiffies;
+	nohz.next_blocked = jiffies;
+	zalloc_cpumask_var(&nohz.idle_cpus_mask, GFP_NOWAIT);
+#endif
+#endif /* SMP */
+
+}
diff --git a/kernel/sched/features.h b/kernel/sched/features.h
new file mode 100644
index 0000000000..f770168230
--- /dev/null
+++ b/kernel/sched/features.h
@@ -0,0 +1,91 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * Using the avg_vruntime, do the right thing and preserve lag across
+ * sleep+wake cycles. EEVDF placement strategy #1, #2 if disabled.
+ */
+SCHED_FEAT(PLACE_LAG, true)
+SCHED_FEAT(PLACE_DEADLINE_INITIAL, true)
+SCHED_FEAT(RUN_TO_PARITY, true)
+
+/*
+ * Prefer to schedule the task we woke last (assuming it failed
+ * wakeup-preemption), since its likely going to consume data we
+ * touched, increases cache locality.
+ */
+SCHED_FEAT(NEXT_BUDDY, false)
+
+/*
+ * Consider buddies to be cache hot, decreases the likeliness of a
+ * cache buddy being migrated away, increases cache locality.
+ */
+SCHED_FEAT(CACHE_HOT_BUDDY, true)
+
+/*
+ * Allow wakeup-time preemption of the current task:
+ */
+SCHED_FEAT(WAKEUP_PREEMPTION, true)
+
+SCHED_FEAT(HRTICK, false)
+SCHED_FEAT(HRTICK_DL, false)
+SCHED_FEAT(DOUBLE_TICK, false)
+
+/*
+ * Decrement CPU capacity based on time not spent running tasks
+ */
+SCHED_FEAT(NONTASK_CAPACITY, true)
+
+#ifdef CONFIG_PREEMPT_RT
+SCHED_FEAT(TTWU_QUEUE, false)
+#else
+
+/*
+ * Queue remote wakeups on the target CPU and process them
+ * using the scheduler IPI. Reduces rq->lock contention/bounces.
+ */
+SCHED_FEAT(TTWU_QUEUE, true)
+#endif
+
+/*
+ * When doing wakeups, attempt to limit superfluous scans of the LLC domain.
+ */
+SCHED_FEAT(SIS_PROP, false)
+SCHED_FEAT(SIS_UTIL, true)
+
+/*
+ * Issue a WARN when we do multiple update_rq_clock() calls
+ * in a single rq->lock section. Default disabled because the
+ * annotations are not complete.
+ */
+SCHED_FEAT(WARN_DOUBLE_CLOCK, false)
+
+#ifdef HAVE_RT_PUSH_IPI
+/*
+ * In order to avoid a thundering herd attack of CPUs that are
+ * lowering their priorities at the same time, and there being
+ * a single CPU that has an RT task that can migrate and is waiting
+ * to run, where the other CPUs will try to take that CPUs
+ * rq lock and possibly create a large contention, sending an
+ * IPI to that CPU and let that CPU push the RT task to where
+ * it should go may be a better scenario.
+ */
+SCHED_FEAT(RT_PUSH_IPI, true)
+#endif
+
+SCHED_FEAT(RT_RUNTIME_SHARE, false)
+SCHED_FEAT(LB_MIN, false)
+SCHED_FEAT(ATTACH_AGE_LOAD, true)
+
+SCHED_FEAT(WA_IDLE, true)
+SCHED_FEAT(WA_WEIGHT, true)
+SCHED_FEAT(WA_BIAS, true)
+
+/*
+ * UtilEstimation. Use estimated CPU utilization.
+ */
+SCHED_FEAT(UTIL_EST, true)
+SCHED_FEAT(UTIL_EST_FASTUP, true)
+
+SCHED_FEAT(LATENCY_WARN, false)
+
+SCHED_FEAT(HZ_BW, true)
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
new file mode 100644
index 0000000000..5007b25c5b
--- /dev/null
+++ b/kernel/sched/idle.c
@@ -0,0 +1,503 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Generic entry points for the idle threads and
+ * implementation of the idle task scheduling class.
+ *
+ * (NOTE: these are not related to SCHED_IDLE batch scheduled
+ *        tasks which are handled in sched/fair.c )
+ */
+
+/* Linker adds these: start and end of __cpuidle functions */
+extern char __cpuidle_text_start[], __cpuidle_text_end[];
+
+/**
+ * sched_idle_set_state - Record idle state for the current CPU.
+ * @idle_state: State to record.
+ */
+void sched_idle_set_state(struct cpuidle_state *idle_state)
+{
+	idle_set_state(this_rq(), idle_state);
+}
+
+static int __read_mostly cpu_idle_force_poll;
+
+void cpu_idle_poll_ctrl(bool enable)
+{
+	if (enable) {
+		cpu_idle_force_poll++;
+	} else {
+		cpu_idle_force_poll--;
+		WARN_ON_ONCE(cpu_idle_force_poll < 0);
+	}
+}
+
+#ifdef CONFIG_GENERIC_IDLE_POLL_SETUP
+static int __init cpu_idle_poll_setup(char *__unused)
+{
+	cpu_idle_force_poll = 1;
+
+	return 1;
+}
+__setup("nohlt", cpu_idle_poll_setup);
+
+static int __init cpu_idle_nopoll_setup(char *__unused)
+{
+	cpu_idle_force_poll = 0;
+
+	return 1;
+}
+__setup("hlt", cpu_idle_nopoll_setup);
+#endif
+
+static noinline int __cpuidle cpu_idle_poll(void)
+{
+	instrumentation_begin();
+	trace_cpu_idle(0, smp_processor_id());
+	stop_critical_timings();
+	ct_cpuidle_enter();
+
+	raw_local_irq_enable();
+	while (!tif_need_resched() &&
+	       (cpu_idle_force_poll || tick_check_broadcast_expired()))
+		cpu_relax();
+	raw_local_irq_disable();
+
+	ct_cpuidle_exit();
+	start_critical_timings();
+	trace_cpu_idle(PWR_EVENT_EXIT, smp_processor_id());
+	local_irq_enable();
+	instrumentation_end();
+
+	return 1;
+}
+
+/* Weak implementations for optional arch specific functions */
+void __weak arch_cpu_idle_prepare(void) { }
+void __weak arch_cpu_idle_enter(void) { }
+void __weak arch_cpu_idle_exit(void) { }
+void __weak __noreturn arch_cpu_idle_dead(void) { while (1); }
+void __weak arch_cpu_idle(void)
+{
+	cpu_idle_force_poll = 1;
+}
+
+/**
+ * default_idle_call - Default CPU idle routine.
+ *
+ * To use when the cpuidle framework cannot be used.
+ */
+void __cpuidle default_idle_call(void)
+{
+	instrumentation_begin();
+	if (!current_clr_polling_and_test()) {
+		trace_cpu_idle(1, smp_processor_id());
+		stop_critical_timings();
+
+		ct_cpuidle_enter();
+		arch_cpu_idle();
+		ct_cpuidle_exit();
+
+		start_critical_timings();
+		trace_cpu_idle(PWR_EVENT_EXIT, smp_processor_id());
+	}
+	local_irq_enable();
+	instrumentation_end();
+}
+
+static int call_cpuidle_s2idle(struct cpuidle_driver *drv,
+			       struct cpuidle_device *dev)
+{
+	if (current_clr_polling_and_test())
+		return -EBUSY;
+
+	return cpuidle_enter_s2idle(drv, dev);
+}
+
+static int call_cpuidle(struct cpuidle_driver *drv, struct cpuidle_device *dev,
+		      int next_state)
+{
+	/*
+	 * The idle task must be scheduled, it is pointless to go to idle, just
+	 * update no idle residency and return.
+	 */
+	if (current_clr_polling_and_test()) {
+		dev->last_residency_ns = 0;
+		local_irq_enable();
+		return -EBUSY;
+	}
+
+	/*
+	 * Enter the idle state previously returned by the governor decision.
+	 * This function will block until an interrupt occurs and will take
+	 * care of re-enabling the local interrupts
+	 */
+	return cpuidle_enter(drv, dev, next_state);
+}
+
+/**
+ * cpuidle_idle_call - the main idle function
+ *
+ * NOTE: no locks or semaphores should be used here
+ *
+ * On architectures that support TIF_POLLING_NRFLAG, is called with polling
+ * set, and it returns with polling set.  If it ever stops polling, it
+ * must clear the polling bit.
+ */
+static void cpuidle_idle_call(void)
+{
+	struct cpuidle_device *dev = cpuidle_get_device();
+	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
+	int next_state, entered_state;
+
+	/*
+	 * Check if the idle task must be rescheduled. If it is the
+	 * case, exit the function after re-enabling the local irq.
+	 */
+	if (need_resched()) {
+		local_irq_enable();
+		return;
+	}
+
+	/*
+	 * The RCU framework needs to be told that we are entering an idle
+	 * section, so no more rcu read side critical sections and one more
+	 * step to the grace period
+	 */
+
+	if (cpuidle_not_available(drv, dev)) {
+		tick_nohz_idle_stop_tick();
+
+		default_idle_call();
+		goto exit_idle;
+	}
+
+	/*
+	 * Suspend-to-idle ("s2idle") is a system state in which all user space
+	 * has been frozen, all I/O devices have been suspended and the only
+	 * activity happens here and in interrupts (if any). In that case bypass
+	 * the cpuidle governor and go straight for the deepest idle state
+	 * available.  Possibly also suspend the local tick and the entire
+	 * timekeeping to prevent timer interrupts from kicking us out of idle
+	 * until a proper wakeup interrupt happens.
+	 */
+
+	if (idle_should_enter_s2idle() || dev->forced_idle_latency_limit_ns) {
+		u64 max_latency_ns;
+
+		if (idle_should_enter_s2idle()) {
+
+			entered_state = call_cpuidle_s2idle(drv, dev);
+			if (entered_state > 0)
+				goto exit_idle;
+
+			max_latency_ns = U64_MAX;
+		} else {
+			max_latency_ns = dev->forced_idle_latency_limit_ns;
+		}
+
+		tick_nohz_idle_stop_tick();
+
+		next_state = cpuidle_find_deepest_state(drv, dev, max_latency_ns);
+		call_cpuidle(drv, dev, next_state);
+	} else {
+		bool stop_tick = true;
+
+		/*
+		 * Ask the cpuidle framework to choose a convenient idle state.
+		 */
+		next_state = cpuidle_select(drv, dev, &stop_tick);
+
+		if (stop_tick || tick_nohz_tick_stopped())
+			tick_nohz_idle_stop_tick();
+		else
+			tick_nohz_idle_retain_tick();
+
+		entered_state = call_cpuidle(drv, dev, next_state);
+		/*
+		 * Give the governor an opportunity to reflect on the outcome
+		 */
+		cpuidle_reflect(dev, entered_state);
+	}
+
+exit_idle:
+	__current_set_polling();
+
+	/*
+	 * It is up to the idle functions to reenable local interrupts
+	 */
+	if (WARN_ON_ONCE(irqs_disabled()))
+		local_irq_enable();
+}
+
+/*
+ * Generic idle loop implementation
+ *
+ * Called with polling cleared.
+ */
+static void do_idle(void)
+{
+	int cpu = smp_processor_id();
+
+	/*
+	 * Check if we need to update blocked load
+	 */
+	nohz_run_idle_balance(cpu);
+
+	/*
+	 * If the arch has a polling bit, we maintain an invariant:
+	 *
+	 * Our polling bit is clear if we're not scheduled (i.e. if rq->curr !=
+	 * rq->idle). This means that, if rq->idle has the polling bit set,
+	 * then setting need_resched is guaranteed to cause the CPU to
+	 * reschedule.
+	 */
+
+	__current_set_polling();
+	tick_nohz_idle_enter();
+
+	while (!need_resched()) {
+		rmb();
+
+		local_irq_disable();
+
+		if (cpu_is_offline(cpu)) {
+			tick_nohz_idle_stop_tick();
+			cpuhp_report_idle_dead();
+			arch_cpu_idle_dead();
+		}
+
+		arch_cpu_idle_enter();
+		rcu_nocb_flush_deferred_wakeup();
+
+		/*
+		 * In poll mode we reenable interrupts and spin. Also if we
+		 * detected in the wakeup from idle path that the tick
+		 * broadcast device expired for us, we don't want to go deep
+		 * idle as we know that the IPI is going to arrive right away.
+		 */
+		if (cpu_idle_force_poll || tick_check_broadcast_expired()) {
+			tick_nohz_idle_restart_tick();
+			cpu_idle_poll();
+		} else {
+			cpuidle_idle_call();
+		}
+		arch_cpu_idle_exit();
+	}
+
+	/*
+	 * Since we fell out of the loop above, we know TIF_NEED_RESCHED must
+	 * be set, propagate it into PREEMPT_NEED_RESCHED.
+	 *
+	 * This is required because for polling idle loops we will not have had
+	 * an IPI to fold the state for us.
+	 */
+	preempt_set_need_resched();
+	tick_nohz_idle_exit();
+	__current_clr_polling();
+
+	/*
+	 * We promise to call sched_ttwu_pending() and reschedule if
+	 * need_resched() is set while polling is set. That means that clearing
+	 * polling needs to be visible before doing these things.
+	 */
+	smp_mb__after_atomic();
+
+	/*
+	 * RCU relies on this call to be done outside of an RCU read-side
+	 * critical section.
+	 */
+	flush_smp_call_function_queue();
+	schedule_idle();
+
+	if (unlikely(klp_patch_pending(current)))
+		klp_update_patch_state(current);
+}
+
+bool cpu_in_idle(unsigned long pc)
+{
+	return pc >= (unsigned long)__cpuidle_text_start &&
+		pc < (unsigned long)__cpuidle_text_end;
+}
+
+struct idle_timer {
+	struct hrtimer timer;
+	int done;
+};
+
+static enum hrtimer_restart idle_inject_timer_fn(struct hrtimer *timer)
+{
+	struct idle_timer *it = container_of(timer, struct idle_timer, timer);
+
+	WRITE_ONCE(it->done, 1);
+	set_tsk_need_resched(current);
+
+	return HRTIMER_NORESTART;
+}
+
+void play_idle_precise(u64 duration_ns, u64 latency_ns)
+{
+	struct idle_timer it;
+
+	/*
+	 * Only FIFO tasks can disable the tick since they don't need the forced
+	 * preemption.
+	 */
+	WARN_ON_ONCE(current->policy != SCHED_FIFO);
+	WARN_ON_ONCE(current->nr_cpus_allowed != 1);
+	WARN_ON_ONCE(!(current->flags & PF_KTHREAD));
+	WARN_ON_ONCE(!(current->flags & PF_NO_SETAFFINITY));
+	WARN_ON_ONCE(!duration_ns);
+	WARN_ON_ONCE(current->mm);
+
+	rcu_sleep_check();
+	preempt_disable();
+	current->flags |= PF_IDLE;
+	cpuidle_use_deepest_state(latency_ns);
+
+	it.done = 0;
+	hrtimer_init_on_stack(&it.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
+	it.timer.function = idle_inject_timer_fn;
+	hrtimer_start(&it.timer, ns_to_ktime(duration_ns),
+		      HRTIMER_MODE_REL_PINNED_HARD);
+
+	while (!READ_ONCE(it.done))
+		do_idle();
+
+	cpuidle_use_deepest_state(0);
+	current->flags &= ~PF_IDLE;
+
+	preempt_fold_need_resched();
+	preempt_enable();
+}
+EXPORT_SYMBOL_GPL(play_idle_precise);
+
+void cpu_startup_entry(enum cpuhp_state state)
+{
+	current->flags |= PF_IDLE;
+	arch_cpu_idle_prepare();
+	cpuhp_online_idle(state);
+	while (1)
+		do_idle();
+}
+
+/*
+ * idle-task scheduling class.
+ */
+
+#ifdef CONFIG_SMP
+static int
+select_task_rq_idle(struct task_struct *p, int cpu, int flags)
+{
+	return task_cpu(p); /* IDLE tasks as never migrated */
+}
+
+static int
+balance_idle(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
+{
+	return WARN_ON_ONCE(1);
+}
+#endif
+
+/*
+ * Idle tasks are unconditionally rescheduled:
+ */
+static void check_preempt_curr_idle(struct rq *rq, struct task_struct *p, int flags)
+{
+	resched_curr(rq);
+}
+
+static void put_prev_task_idle(struct rq *rq, struct task_struct *prev)
+{
+}
+
+static void set_next_task_idle(struct rq *rq, struct task_struct *next, bool first)
+{
+	update_idle_core(rq);
+	schedstat_inc(rq->sched_goidle);
+}
+
+#ifdef CONFIG_SMP
+static struct task_struct *pick_task_idle(struct rq *rq)
+{
+	return rq->idle;
+}
+#endif
+
+struct task_struct *pick_next_task_idle(struct rq *rq)
+{
+	struct task_struct *next = rq->idle;
+
+	set_next_task_idle(rq, next, true);
+
+	return next;
+}
+
+/*
+ * It is not legal to sleep in the idle task - print a warning
+ * message if some code attempts to do it:
+ */
+static void
+dequeue_task_idle(struct rq *rq, struct task_struct *p, int flags)
+{
+	raw_spin_rq_unlock_irq(rq);
+	printk(KERN_ERR "bad: scheduling from the idle thread!\n");
+	dump_stack();
+	raw_spin_rq_lock_irq(rq);
+}
+
+/*
+ * scheduler tick hitting a task of our scheduling class.
+ *
+ * NOTE: This function can be called remotely by the tick offload that
+ * goes along full dynticks. Therefore no local assumption can be made
+ * and everything must be accessed through the @rq and @curr passed in
+ * parameters.
+ */
+static void task_tick_idle(struct rq *rq, struct task_struct *curr, int queued)
+{
+}
+
+static void switched_to_idle(struct rq *rq, struct task_struct *p)
+{
+	BUG();
+}
+
+static void
+prio_changed_idle(struct rq *rq, struct task_struct *p, int oldprio)
+{
+	BUG();
+}
+
+static void update_curr_idle(struct rq *rq)
+{
+}
+
+/*
+ * Simple, special scheduling class for the per-CPU idle tasks:
+ */
+DEFINE_SCHED_CLASS(idle) = {
+
+	/* no enqueue/yield_task for idle tasks */
+
+	/* dequeue is not valid, we print a debug message there: */
+	.dequeue_task		= dequeue_task_idle,
+
+	.check_preempt_curr	= check_preempt_curr_idle,
+
+	.pick_next_task		= pick_next_task_idle,
+	.put_prev_task		= put_prev_task_idle,
+	.set_next_task          = set_next_task_idle,
+
+#ifdef CONFIG_SMP
+	.balance		= balance_idle,
+	.pick_task		= pick_task_idle,
+	.select_task_rq		= select_task_rq_idle,
+	.set_cpus_allowed	= set_cpus_allowed_common,
+#endif
+
+	.task_tick		= task_tick_idle,
+
+	.prio_changed		= prio_changed_idle,
+	.switched_to		= switched_to_idle,
+	.update_curr		= update_curr_idle,
+};
diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c
new file mode 100644
index 0000000000..373d42c707
--- /dev/null
+++ b/kernel/sched/isolation.c
@@ -0,0 +1,241 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Housekeeping management. Manage the targets for routine code that can run on
+ *  any CPU: unbound workqueues, timers, kthreads and any offloadable work.
+ *
+ * Copyright (C) 2017 Red Hat, Inc., Frederic Weisbecker
+ * Copyright (C) 2017-2018 SUSE, Frederic Weisbecker
+ *
+ */
+
+enum hk_flags {
+	HK_FLAG_TIMER		= BIT(HK_TYPE_TIMER),
+	HK_FLAG_RCU		= BIT(HK_TYPE_RCU),
+	HK_FLAG_MISC		= BIT(HK_TYPE_MISC),
+	HK_FLAG_SCHED		= BIT(HK_TYPE_SCHED),
+	HK_FLAG_TICK		= BIT(HK_TYPE_TICK),
+	HK_FLAG_DOMAIN		= BIT(HK_TYPE_DOMAIN),
+	HK_FLAG_WQ		= BIT(HK_TYPE_WQ),
+	HK_FLAG_MANAGED_IRQ	= BIT(HK_TYPE_MANAGED_IRQ),
+	HK_FLAG_KTHREAD		= BIT(HK_TYPE_KTHREAD),
+};
+
+DEFINE_STATIC_KEY_FALSE(housekeeping_overridden);
+EXPORT_SYMBOL_GPL(housekeeping_overridden);
+
+struct housekeeping {
+	cpumask_var_t cpumasks[HK_TYPE_MAX];
+	unsigned long flags;
+};
+
+static struct housekeeping housekeeping;
+
+bool housekeeping_enabled(enum hk_type type)
+{
+	return !!(housekeeping.flags & BIT(type));
+}
+EXPORT_SYMBOL_GPL(housekeeping_enabled);
+
+int housekeeping_any_cpu(enum hk_type type)
+{
+	int cpu;
+
+	if (static_branch_unlikely(&housekeeping_overridden)) {
+		if (housekeeping.flags & BIT(type)) {
+			cpu = sched_numa_find_closest(housekeeping.cpumasks[type], smp_processor_id());
+			if (cpu < nr_cpu_ids)
+				return cpu;
+
+			return cpumask_any_and(housekeeping.cpumasks[type], cpu_online_mask);
+		}
+	}
+	return smp_processor_id();
+}
+EXPORT_SYMBOL_GPL(housekeeping_any_cpu);
+
+const struct cpumask *housekeeping_cpumask(enum hk_type type)
+{
+	if (static_branch_unlikely(&housekeeping_overridden))
+		if (housekeeping.flags & BIT(type))
+			return housekeeping.cpumasks[type];
+	return cpu_possible_mask;
+}
+EXPORT_SYMBOL_GPL(housekeeping_cpumask);
+
+void housekeeping_affine(struct task_struct *t, enum hk_type type)
+{
+	if (static_branch_unlikely(&housekeeping_overridden))
+		if (housekeeping.flags & BIT(type))
+			set_cpus_allowed_ptr(t, housekeeping.cpumasks[type]);
+}
+EXPORT_SYMBOL_GPL(housekeeping_affine);
+
+bool housekeeping_test_cpu(int cpu, enum hk_type type)
+{
+	if (static_branch_unlikely(&housekeeping_overridden))
+		if (housekeeping.flags & BIT(type))
+			return cpumask_test_cpu(cpu, housekeeping.cpumasks[type]);
+	return true;
+}
+EXPORT_SYMBOL_GPL(housekeeping_test_cpu);
+
+void __init housekeeping_init(void)
+{
+	enum hk_type type;
+
+	if (!housekeeping.flags)
+		return;
+
+	static_branch_enable(&housekeeping_overridden);
+
+	if (housekeeping.flags & HK_FLAG_TICK)
+		sched_tick_offload_init();
+
+	for_each_set_bit(type, &housekeeping.flags, HK_TYPE_MAX) {
+		/* We need at least one CPU to handle housekeeping work */
+		WARN_ON_ONCE(cpumask_empty(housekeeping.cpumasks[type]));
+	}
+}
+
+static void __init housekeeping_setup_type(enum hk_type type,
+					   cpumask_var_t housekeeping_staging)
+{
+
+	alloc_bootmem_cpumask_var(&housekeeping.cpumasks[type]);
+	cpumask_copy(housekeeping.cpumasks[type],
+		     housekeeping_staging);
+}
+
+static int __init housekeeping_setup(char *str, unsigned long flags)
+{
+	cpumask_var_t non_housekeeping_mask, housekeeping_staging;
+	int err = 0;
+
+	if ((flags & HK_FLAG_TICK) && !(housekeeping.flags & HK_FLAG_TICK)) {
+		if (!IS_ENABLED(CONFIG_NO_HZ_FULL)) {
+			pr_warn("Housekeeping: nohz unsupported."
+				" Build with CONFIG_NO_HZ_FULL\n");
+			return 0;
+		}
+	}
+
+	alloc_bootmem_cpumask_var(&non_housekeeping_mask);
+	if (cpulist_parse(str, non_housekeeping_mask) < 0) {
+		pr_warn("Housekeeping: nohz_full= or isolcpus= incorrect CPU range\n");
+		goto free_non_housekeeping_mask;
+	}
+
+	alloc_bootmem_cpumask_var(&housekeeping_staging);
+	cpumask_andnot(housekeeping_staging,
+		       cpu_possible_mask, non_housekeeping_mask);
+
+	if (!cpumask_intersects(cpu_present_mask, housekeeping_staging)) {
+		__cpumask_set_cpu(smp_processor_id(), housekeeping_staging);
+		__cpumask_clear_cpu(smp_processor_id(), non_housekeeping_mask);
+		if (!housekeeping.flags) {
+			pr_warn("Housekeeping: must include one present CPU, "
+				"using boot CPU:%d\n", smp_processor_id());
+		}
+	}
+
+	if (!housekeeping.flags) {
+		/* First setup call ("nohz_full=" or "isolcpus=") */
+		enum hk_type type;
+
+		for_each_set_bit(type, &flags, HK_TYPE_MAX)
+			housekeeping_setup_type(type, housekeeping_staging);
+	} else {
+		/* Second setup call ("nohz_full=" after "isolcpus=" or the reverse) */
+		enum hk_type type;
+		unsigned long iter_flags = flags & housekeeping.flags;
+
+		for_each_set_bit(type, &iter_flags, HK_TYPE_MAX) {
+			if (!cpumask_equal(housekeeping_staging,
+					   housekeeping.cpumasks[type])) {
+				pr_warn("Housekeeping: nohz_full= must match isolcpus=\n");
+				goto free_housekeeping_staging;
+			}
+		}
+
+		iter_flags = flags & ~housekeeping.flags;
+
+		for_each_set_bit(type, &iter_flags, HK_TYPE_MAX)
+			housekeeping_setup_type(type, housekeeping_staging);
+	}
+
+	if ((flags & HK_FLAG_TICK) && !(housekeeping.flags & HK_FLAG_TICK))
+		tick_nohz_full_setup(non_housekeeping_mask);
+
+	housekeeping.flags |= flags;
+	err = 1;
+
+free_housekeeping_staging:
+	free_bootmem_cpumask_var(housekeeping_staging);
+free_non_housekeeping_mask:
+	free_bootmem_cpumask_var(non_housekeeping_mask);
+
+	return err;
+}
+
+static int __init housekeeping_nohz_full_setup(char *str)
+{
+	unsigned long flags;
+
+	flags = HK_FLAG_TICK | HK_FLAG_WQ | HK_FLAG_TIMER | HK_FLAG_RCU |
+		HK_FLAG_MISC | HK_FLAG_KTHREAD;
+
+	return housekeeping_setup(str, flags);
+}
+__setup("nohz_full=", housekeeping_nohz_full_setup);
+
+static int __init housekeeping_isolcpus_setup(char *str)
+{
+	unsigned long flags = 0;
+	bool illegal = false;
+	char *par;
+	int len;
+
+	while (isalpha(*str)) {
+		if (!strncmp(str, "nohz,", 5)) {
+			str += 5;
+			flags |= HK_FLAG_TICK;
+			continue;
+		}
+
+		if (!strncmp(str, "domain,", 7)) {
+			str += 7;
+			flags |= HK_FLAG_DOMAIN;
+			continue;
+		}
+
+		if (!strncmp(str, "managed_irq,", 12)) {
+			str += 12;
+			flags |= HK_FLAG_MANAGED_IRQ;
+			continue;
+		}
+
+		/*
+		 * Skip unknown sub-parameter and validate that it is not
+		 * containing an invalid character.
+		 */
+		for (par = str, len = 0; *str && *str != ','; str++, len++) {
+			if (!isalpha(*str) && *str != '_')
+				illegal = true;
+		}
+
+		if (illegal) {
+			pr_warn("isolcpus: Invalid flag %.*s\n", len, par);
+			return 0;
+		}
+
+		pr_info("isolcpus: Skipped unknown flag %.*s\n", len, par);
+		str++;
+	}
+
+	/* Default behaviour for isolcpus without flags */
+	if (!flags)
+		flags |= HK_FLAG_DOMAIN;
+
+	return housekeeping_setup(str, flags);
+}
+__setup("isolcpus=", housekeeping_isolcpus_setup);
diff --git a/kernel/sched/loadavg.c b/kernel/sched/loadavg.c
new file mode 100644
index 0000000000..52c8f8226b
--- /dev/null
+++ b/kernel/sched/loadavg.c
@@ -0,0 +1,397 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * kernel/sched/loadavg.c
+ *
+ * This file contains the magic bits required to compute the global loadavg
+ * figure. Its a silly number but people think its important. We go through
+ * great pains to make it work on big machines and tickless kernels.
+ */
+
+/*
+ * Global load-average calculations
+ *
+ * We take a distributed and async approach to calculating the global load-avg
+ * in order to minimize overhead.
+ *
+ * The global load average is an exponentially decaying average of nr_running +
+ * nr_uninterruptible.
+ *
+ * Once every LOAD_FREQ:
+ *
+ *   nr_active = 0;
+ *   for_each_possible_cpu(cpu)
+ *	nr_active += cpu_of(cpu)->nr_running + cpu_of(cpu)->nr_uninterruptible;
+ *
+ *   avenrun[n] = avenrun[0] * exp_n + nr_active * (1 - exp_n)
+ *
+ * Due to a number of reasons the above turns in the mess below:
+ *
+ *  - for_each_possible_cpu() is prohibitively expensive on machines with
+ *    serious number of CPUs, therefore we need to take a distributed approach
+ *    to calculating nr_active.
+ *
+ *        \Sum_i x_i(t) = \Sum_i x_i(t) - x_i(t_0) | x_i(t_0) := 0
+ *                      = \Sum_i { \Sum_j=1 x_i(t_j) - x_i(t_j-1) }
+ *
+ *    So assuming nr_active := 0 when we start out -- true per definition, we
+ *    can simply take per-CPU deltas and fold those into a global accumulate
+ *    to obtain the same result. See calc_load_fold_active().
+ *
+ *    Furthermore, in order to avoid synchronizing all per-CPU delta folding
+ *    across the machine, we assume 10 ticks is sufficient time for every
+ *    CPU to have completed this task.
+ *
+ *    This places an upper-bound on the IRQ-off latency of the machine. Then
+ *    again, being late doesn't loose the delta, just wrecks the sample.
+ *
+ *  - cpu_rq()->nr_uninterruptible isn't accurately tracked per-CPU because
+ *    this would add another cross-CPU cacheline miss and atomic operation
+ *    to the wakeup path. Instead we increment on whatever CPU the task ran
+ *    when it went into uninterruptible state and decrement on whatever CPU
+ *    did the wakeup. This means that only the sum of nr_uninterruptible over
+ *    all CPUs yields the correct result.
+ *
+ *  This covers the NO_HZ=n code, for extra head-aches, see the comment below.
+ */
+
+/* Variables and functions for calc_load */
+atomic_long_t calc_load_tasks;
+unsigned long calc_load_update;
+unsigned long avenrun[3];
+EXPORT_SYMBOL(avenrun); /* should be removed */
+
+/**
+ * get_avenrun - get the load average array
+ * @loads:	pointer to dest load array
+ * @offset:	offset to add
+ * @shift:	shift count to shift the result left
+ *
+ * These values are estimates at best, so no need for locking.
+ */
+void get_avenrun(unsigned long *loads, unsigned long offset, int shift)
+{
+	loads[0] = (avenrun[0] + offset) << shift;
+	loads[1] = (avenrun[1] + offset) << shift;
+	loads[2] = (avenrun[2] + offset) << shift;
+}
+
+long calc_load_fold_active(struct rq *this_rq, long adjust)
+{
+	long nr_active, delta = 0;
+
+	nr_active = this_rq->nr_running - adjust;
+	nr_active += (int)this_rq->nr_uninterruptible;
+
+	if (nr_active != this_rq->calc_load_active) {
+		delta = nr_active - this_rq->calc_load_active;
+		this_rq->calc_load_active = nr_active;
+	}
+
+	return delta;
+}
+
+/**
+ * fixed_power_int - compute: x^n, in O(log n) time
+ *
+ * @x:         base of the power
+ * @frac_bits: fractional bits of @x
+ * @n:         power to raise @x to.
+ *
+ * By exploiting the relation between the definition of the natural power
+ * function: x^n := x*x*...*x (x multiplied by itself for n times), and
+ * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i,
+ * (where: n_i \elem {0, 1}, the binary vector representing n),
+ * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is
+ * of course trivially computable in O(log_2 n), the length of our binary
+ * vector.
+ */
+static unsigned long
+fixed_power_int(unsigned long x, unsigned int frac_bits, unsigned int n)
+{
+	unsigned long result = 1UL << frac_bits;
+
+	if (n) {
+		for (;;) {
+			if (n & 1) {
+				result *= x;
+				result += 1UL << (frac_bits - 1);
+				result >>= frac_bits;
+			}
+			n >>= 1;
+			if (!n)
+				break;
+			x *= x;
+			x += 1UL << (frac_bits - 1);
+			x >>= frac_bits;
+		}
+	}
+
+	return result;
+}
+
+/*
+ * a1 = a0 * e + a * (1 - e)
+ *
+ * a2 = a1 * e + a * (1 - e)
+ *    = (a0 * e + a * (1 - e)) * e + a * (1 - e)
+ *    = a0 * e^2 + a * (1 - e) * (1 + e)
+ *
+ * a3 = a2 * e + a * (1 - e)
+ *    = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e)
+ *    = a0 * e^3 + a * (1 - e) * (1 + e + e^2)
+ *
+ *  ...
+ *
+ * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1]
+ *    = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e)
+ *    = a0 * e^n + a * (1 - e^n)
+ *
+ * [1] application of the geometric series:
+ *
+ *              n         1 - x^(n+1)
+ *     S_n := \Sum x^i = -------------
+ *             i=0          1 - x
+ */
+unsigned long
+calc_load_n(unsigned long load, unsigned long exp,
+	    unsigned long active, unsigned int n)
+{
+	return calc_load(load, fixed_power_int(exp, FSHIFT, n), active);
+}
+
+#ifdef CONFIG_NO_HZ_COMMON
+/*
+ * Handle NO_HZ for the global load-average.
+ *
+ * Since the above described distributed algorithm to compute the global
+ * load-average relies on per-CPU sampling from the tick, it is affected by
+ * NO_HZ.
+ *
+ * The basic idea is to fold the nr_active delta into a global NO_HZ-delta upon
+ * entering NO_HZ state such that we can include this as an 'extra' CPU delta
+ * when we read the global state.
+ *
+ * Obviously reality has to ruin such a delightfully simple scheme:
+ *
+ *  - When we go NO_HZ idle during the window, we can negate our sample
+ *    contribution, causing under-accounting.
+ *
+ *    We avoid this by keeping two NO_HZ-delta counters and flipping them
+ *    when the window starts, thus separating old and new NO_HZ load.
+ *
+ *    The only trick is the slight shift in index flip for read vs write.
+ *
+ *        0s            5s            10s           15s
+ *          +10           +10           +10           +10
+ *        |-|-----------|-|-----------|-|-----------|-|
+ *    r:0 0 1           1 0           0 1           1 0
+ *    w:0 1 1           0 0           1 1           0 0
+ *
+ *    This ensures we'll fold the old NO_HZ contribution in this window while
+ *    accumulating the new one.
+ *
+ *  - When we wake up from NO_HZ during the window, we push up our
+ *    contribution, since we effectively move our sample point to a known
+ *    busy state.
+ *
+ *    This is solved by pushing the window forward, and thus skipping the
+ *    sample, for this CPU (effectively using the NO_HZ-delta for this CPU which
+ *    was in effect at the time the window opened). This also solves the issue
+ *    of having to deal with a CPU having been in NO_HZ for multiple LOAD_FREQ
+ *    intervals.
+ *
+ * When making the ILB scale, we should try to pull this in as well.
+ */
+static atomic_long_t calc_load_nohz[2];
+static int calc_load_idx;
+
+static inline int calc_load_write_idx(void)
+{
+	int idx = calc_load_idx;
+
+	/*
+	 * See calc_global_nohz(), if we observe the new index, we also
+	 * need to observe the new update time.
+	 */
+	smp_rmb();
+
+	/*
+	 * If the folding window started, make sure we start writing in the
+	 * next NO_HZ-delta.
+	 */
+	if (!time_before(jiffies, READ_ONCE(calc_load_update)))
+		idx++;
+
+	return idx & 1;
+}
+
+static inline int calc_load_read_idx(void)
+{
+	return calc_load_idx & 1;
+}
+
+static void calc_load_nohz_fold(struct rq *rq)
+{
+	long delta;
+
+	delta = calc_load_fold_active(rq, 0);
+	if (delta) {
+		int idx = calc_load_write_idx();
+
+		atomic_long_add(delta, &calc_load_nohz[idx]);
+	}
+}
+
+void calc_load_nohz_start(void)
+{
+	/*
+	 * We're going into NO_HZ mode, if there's any pending delta, fold it
+	 * into the pending NO_HZ delta.
+	 */
+	calc_load_nohz_fold(this_rq());
+}
+
+/*
+ * Keep track of the load for NOHZ_FULL, must be called between
+ * calc_load_nohz_{start,stop}().
+ */
+void calc_load_nohz_remote(struct rq *rq)
+{
+	calc_load_nohz_fold(rq);
+}
+
+void calc_load_nohz_stop(void)
+{
+	struct rq *this_rq = this_rq();
+
+	/*
+	 * If we're still before the pending sample window, we're done.
+	 */
+	this_rq->calc_load_update = READ_ONCE(calc_load_update);
+	if (time_before(jiffies, this_rq->calc_load_update))
+		return;
+
+	/*
+	 * We woke inside or after the sample window, this means we're already
+	 * accounted through the nohz accounting, so skip the entire deal and
+	 * sync up for the next window.
+	 */
+	if (time_before(jiffies, this_rq->calc_load_update + 10))
+		this_rq->calc_load_update += LOAD_FREQ;
+}
+
+static long calc_load_nohz_read(void)
+{
+	int idx = calc_load_read_idx();
+	long delta = 0;
+
+	if (atomic_long_read(&calc_load_nohz[idx]))
+		delta = atomic_long_xchg(&calc_load_nohz[idx], 0);
+
+	return delta;
+}
+
+/*
+ * NO_HZ can leave us missing all per-CPU ticks calling
+ * calc_load_fold_active(), but since a NO_HZ CPU folds its delta into
+ * calc_load_nohz per calc_load_nohz_start(), all we need to do is fold
+ * in the pending NO_HZ delta if our NO_HZ period crossed a load cycle boundary.
+ *
+ * Once we've updated the global active value, we need to apply the exponential
+ * weights adjusted to the number of cycles missed.
+ */
+static void calc_global_nohz(void)
+{
+	unsigned long sample_window;
+	long delta, active, n;
+
+	sample_window = READ_ONCE(calc_load_update);
+	if (!time_before(jiffies, sample_window + 10)) {
+		/*
+		 * Catch-up, fold however many we are behind still
+		 */
+		delta = jiffies - sample_window - 10;
+		n = 1 + (delta / LOAD_FREQ);
+
+		active = atomic_long_read(&calc_load_tasks);
+		active = active > 0 ? active * FIXED_1 : 0;
+
+		avenrun[0] = calc_load_n(avenrun[0], EXP_1, active, n);
+		avenrun[1] = calc_load_n(avenrun[1], EXP_5, active, n);
+		avenrun[2] = calc_load_n(avenrun[2], EXP_15, active, n);
+
+		WRITE_ONCE(calc_load_update, sample_window + n * LOAD_FREQ);
+	}
+
+	/*
+	 * Flip the NO_HZ index...
+	 *
+	 * Make sure we first write the new time then flip the index, so that
+	 * calc_load_write_idx() will see the new time when it reads the new
+	 * index, this avoids a double flip messing things up.
+	 */
+	smp_wmb();
+	calc_load_idx++;
+}
+#else /* !CONFIG_NO_HZ_COMMON */
+
+static inline long calc_load_nohz_read(void) { return 0; }
+static inline void calc_global_nohz(void) { }
+
+#endif /* CONFIG_NO_HZ_COMMON */
+
+/*
+ * calc_load - update the avenrun load estimates 10 ticks after the
+ * CPUs have updated calc_load_tasks.
+ *
+ * Called from the global timer code.
+ */
+void calc_global_load(void)
+{
+	unsigned long sample_window;
+	long active, delta;
+
+	sample_window = READ_ONCE(calc_load_update);
+	if (time_before(jiffies, sample_window + 10))
+		return;
+
+	/*
+	 * Fold the 'old' NO_HZ-delta to include all NO_HZ CPUs.
+	 */
+	delta = calc_load_nohz_read();
+	if (delta)
+		atomic_long_add(delta, &calc_load_tasks);
+
+	active = atomic_long_read(&calc_load_tasks);
+	active = active > 0 ? active * FIXED_1 : 0;
+
+	avenrun[0] = calc_load(avenrun[0], EXP_1, active);
+	avenrun[1] = calc_load(avenrun[1], EXP_5, active);
+	avenrun[2] = calc_load(avenrun[2], EXP_15, active);
+
+	WRITE_ONCE(calc_load_update, sample_window + LOAD_FREQ);
+
+	/*
+	 * In case we went to NO_HZ for multiple LOAD_FREQ intervals
+	 * catch up in bulk.
+	 */
+	calc_global_nohz();
+}
+
+/*
+ * Called from scheduler_tick() to periodically update this CPU's
+ * active count.
+ */
+void calc_global_load_tick(struct rq *this_rq)
+{
+	long delta;
+
+	if (time_before(jiffies, this_rq->calc_load_update))
+		return;
+
+	delta  = calc_load_fold_active(this_rq, 0);
+	if (delta)
+		atomic_long_add(delta, &calc_load_tasks);
+
+	this_rq->calc_load_update += LOAD_FREQ;
+}
diff --git a/kernel/sched/membarrier.c b/kernel/sched/membarrier.c
new file mode 100644
index 0000000000..2ad881d077
--- /dev/null
+++ b/kernel/sched/membarrier.c
@@ -0,0 +1,666 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2010-2017 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * membarrier system call
+ */
+
+/*
+ * For documentation purposes, here are some membarrier ordering
+ * scenarios to keep in mind:
+ *
+ * A) Userspace thread execution after IPI vs membarrier's memory
+ *    barrier before sending the IPI
+ *
+ * Userspace variables:
+ *
+ * int x = 0, y = 0;
+ *
+ * The memory barrier at the start of membarrier() on CPU0 is necessary in
+ * order to enforce the guarantee that any writes occurring on CPU0 before
+ * the membarrier() is executed will be visible to any code executing on
+ * CPU1 after the IPI-induced memory barrier:
+ *
+ *         CPU0                              CPU1
+ *
+ *         x = 1
+ *         membarrier():
+ *           a: smp_mb()
+ *           b: send IPI                       IPI-induced mb
+ *           c: smp_mb()
+ *         r2 = y
+ *                                           y = 1
+ *                                           barrier()
+ *                                           r1 = x
+ *
+ *                     BUG_ON(r1 == 0 && r2 == 0)
+ *
+ * The write to y and load from x by CPU1 are unordered by the hardware,
+ * so it's possible to have "r1 = x" reordered before "y = 1" at any
+ * point after (b).  If the memory barrier at (a) is omitted, then "x = 1"
+ * can be reordered after (a) (although not after (c)), so we get r1 == 0
+ * and r2 == 0.  This violates the guarantee that membarrier() is
+ * supposed by provide.
+ *
+ * The timing of the memory barrier at (a) has to ensure that it executes
+ * before the IPI-induced memory barrier on CPU1.
+ *
+ * B) Userspace thread execution before IPI vs membarrier's memory
+ *    barrier after completing the IPI
+ *
+ * Userspace variables:
+ *
+ * int x = 0, y = 0;
+ *
+ * The memory barrier at the end of membarrier() on CPU0 is necessary in
+ * order to enforce the guarantee that any writes occurring on CPU1 before
+ * the membarrier() is executed will be visible to any code executing on
+ * CPU0 after the membarrier():
+ *
+ *         CPU0                              CPU1
+ *
+ *                                           x = 1
+ *                                           barrier()
+ *                                           y = 1
+ *         r2 = y
+ *         membarrier():
+ *           a: smp_mb()
+ *           b: send IPI                       IPI-induced mb
+ *           c: smp_mb()
+ *         r1 = x
+ *         BUG_ON(r1 == 0 && r2 == 1)
+ *
+ * The writes to x and y are unordered by the hardware, so it's possible to
+ * have "r2 = 1" even though the write to x doesn't execute until (b).  If
+ * the memory barrier at (c) is omitted then "r1 = x" can be reordered
+ * before (b) (although not before (a)), so we get "r1 = 0".  This violates
+ * the guarantee that membarrier() is supposed to provide.
+ *
+ * The timing of the memory barrier at (c) has to ensure that it executes
+ * after the IPI-induced memory barrier on CPU1.
+ *
+ * C) Scheduling userspace thread -> kthread -> userspace thread vs membarrier
+ *
+ *           CPU0                            CPU1
+ *
+ *           membarrier():
+ *           a: smp_mb()
+ *                                           d: switch to kthread (includes mb)
+ *           b: read rq->curr->mm == NULL
+ *                                           e: switch to user (includes mb)
+ *           c: smp_mb()
+ *
+ * Using the scenario from (A), we can show that (a) needs to be paired
+ * with (e). Using the scenario from (B), we can show that (c) needs to
+ * be paired with (d).
+ *
+ * D) exit_mm vs membarrier
+ *
+ * Two thread groups are created, A and B.  Thread group B is created by
+ * issuing clone from group A with flag CLONE_VM set, but not CLONE_THREAD.
+ * Let's assume we have a single thread within each thread group (Thread A
+ * and Thread B).  Thread A runs on CPU0, Thread B runs on CPU1.
+ *
+ *           CPU0                            CPU1
+ *
+ *           membarrier():
+ *             a: smp_mb()
+ *                                           exit_mm():
+ *                                             d: smp_mb()
+ *                                             e: current->mm = NULL
+ *             b: read rq->curr->mm == NULL
+ *             c: smp_mb()
+ *
+ * Using scenario (B), we can show that (c) needs to be paired with (d).
+ *
+ * E) kthread_{use,unuse}_mm vs membarrier
+ *
+ *           CPU0                            CPU1
+ *
+ *           membarrier():
+ *           a: smp_mb()
+ *                                           kthread_unuse_mm()
+ *                                             d: smp_mb()
+ *                                             e: current->mm = NULL
+ *           b: read rq->curr->mm == NULL
+ *                                           kthread_use_mm()
+ *                                             f: current->mm = mm
+ *                                             g: smp_mb()
+ *           c: smp_mb()
+ *
+ * Using the scenario from (A), we can show that (a) needs to be paired
+ * with (g). Using the scenario from (B), we can show that (c) needs to
+ * be paired with (d).
+ */
+
+/*
+ * Bitmask made from a "or" of all commands within enum membarrier_cmd,
+ * except MEMBARRIER_CMD_QUERY.
+ */
+#ifdef CONFIG_ARCH_HAS_MEMBARRIER_SYNC_CORE
+#define MEMBARRIER_PRIVATE_EXPEDITED_SYNC_CORE_BITMASK			\
+	(MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE			\
+	| MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_SYNC_CORE)
+#else
+#define MEMBARRIER_PRIVATE_EXPEDITED_SYNC_CORE_BITMASK	0
+#endif
+
+#ifdef CONFIG_RSEQ
+#define MEMBARRIER_PRIVATE_EXPEDITED_RSEQ_BITMASK		\
+	(MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ			\
+	| MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ)
+#else
+#define MEMBARRIER_PRIVATE_EXPEDITED_RSEQ_BITMASK	0
+#endif
+
+#define MEMBARRIER_CMD_BITMASK						\
+	(MEMBARRIER_CMD_GLOBAL | MEMBARRIER_CMD_GLOBAL_EXPEDITED	\
+	| MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED			\
+	| MEMBARRIER_CMD_PRIVATE_EXPEDITED				\
+	| MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED			\
+	| MEMBARRIER_PRIVATE_EXPEDITED_SYNC_CORE_BITMASK		\
+	| MEMBARRIER_PRIVATE_EXPEDITED_RSEQ_BITMASK			\
+	| MEMBARRIER_CMD_GET_REGISTRATIONS)
+
+static void ipi_mb(void *info)
+{
+	smp_mb();	/* IPIs should be serializing but paranoid. */
+}
+
+static void ipi_sync_core(void *info)
+{
+	/*
+	 * The smp_mb() in membarrier after all the IPIs is supposed to
+	 * ensure that memory on remote CPUs that occur before the IPI
+	 * become visible to membarrier()'s caller -- see scenario B in
+	 * the big comment at the top of this file.
+	 *
+	 * A sync_core() would provide this guarantee, but
+	 * sync_core_before_usermode() might end up being deferred until
+	 * after membarrier()'s smp_mb().
+	 */
+	smp_mb();	/* IPIs should be serializing but paranoid. */
+
+	sync_core_before_usermode();
+}
+
+static void ipi_rseq(void *info)
+{
+	/*
+	 * Ensure that all stores done by the calling thread are visible
+	 * to the current task before the current task resumes.  We could
+	 * probably optimize this away on most architectures, but by the
+	 * time we've already sent an IPI, the cost of the extra smp_mb()
+	 * is negligible.
+	 */
+	smp_mb();
+	rseq_preempt(current);
+}
+
+static void ipi_sync_rq_state(void *info)
+{
+	struct mm_struct *mm = (struct mm_struct *) info;
+
+	if (current->mm != mm)
+		return;
+	this_cpu_write(runqueues.membarrier_state,
+		       atomic_read(&mm->membarrier_state));
+	/*
+	 * Issue a memory barrier after setting
+	 * MEMBARRIER_STATE_GLOBAL_EXPEDITED in the current runqueue to
+	 * guarantee that no memory access following registration is reordered
+	 * before registration.
+	 */
+	smp_mb();
+}
+
+void membarrier_exec_mmap(struct mm_struct *mm)
+{
+	/*
+	 * Issue a memory barrier before clearing membarrier_state to
+	 * guarantee that no memory access prior to exec is reordered after
+	 * clearing this state.
+	 */
+	smp_mb();
+	atomic_set(&mm->membarrier_state, 0);
+	/*
+	 * Keep the runqueue membarrier_state in sync with this mm
+	 * membarrier_state.
+	 */
+	this_cpu_write(runqueues.membarrier_state, 0);
+}
+
+void membarrier_update_current_mm(struct mm_struct *next_mm)
+{
+	struct rq *rq = this_rq();
+	int membarrier_state = 0;
+
+	if (next_mm)
+		membarrier_state = atomic_read(&next_mm->membarrier_state);
+	if (READ_ONCE(rq->membarrier_state) == membarrier_state)
+		return;
+	WRITE_ONCE(rq->membarrier_state, membarrier_state);
+}
+
+static int membarrier_global_expedited(void)
+{
+	int cpu;
+	cpumask_var_t tmpmask;
+
+	if (num_online_cpus() == 1)
+		return 0;
+
+	/*
+	 * Matches memory barriers around rq->curr modification in
+	 * scheduler.
+	 */
+	smp_mb();	/* system call entry is not a mb. */
+
+	if (!zalloc_cpumask_var(&tmpmask, GFP_KERNEL))
+		return -ENOMEM;
+
+	cpus_read_lock();
+	rcu_read_lock();
+	for_each_online_cpu(cpu) {
+		struct task_struct *p;
+
+		/*
+		 * Skipping the current CPU is OK even through we can be
+		 * migrated at any point. The current CPU, at the point
+		 * where we read raw_smp_processor_id(), is ensured to
+		 * be in program order with respect to the caller
+		 * thread. Therefore, we can skip this CPU from the
+		 * iteration.
+		 */
+		if (cpu == raw_smp_processor_id())
+			continue;
+
+		if (!(READ_ONCE(cpu_rq(cpu)->membarrier_state) &
+		    MEMBARRIER_STATE_GLOBAL_EXPEDITED))
+			continue;
+
+		/*
+		 * Skip the CPU if it runs a kernel thread which is not using
+		 * a task mm.
+		 */
+		p = rcu_dereference(cpu_rq(cpu)->curr);
+		if (!p->mm)
+			continue;
+
+		__cpumask_set_cpu(cpu, tmpmask);
+	}
+	rcu_read_unlock();
+
+	preempt_disable();
+	smp_call_function_many(tmpmask, ipi_mb, NULL, 1);
+	preempt_enable();
+
+	free_cpumask_var(tmpmask);
+	cpus_read_unlock();
+
+	/*
+	 * Memory barrier on the caller thread _after_ we finished
+	 * waiting for the last IPI. Matches memory barriers around
+	 * rq->curr modification in scheduler.
+	 */
+	smp_mb();	/* exit from system call is not a mb */
+	return 0;
+}
+
+static int membarrier_private_expedited(int flags, int cpu_id)
+{
+	cpumask_var_t tmpmask;
+	struct mm_struct *mm = current->mm;
+	smp_call_func_t ipi_func = ipi_mb;
+
+	if (flags == MEMBARRIER_FLAG_SYNC_CORE) {
+		if (!IS_ENABLED(CONFIG_ARCH_HAS_MEMBARRIER_SYNC_CORE))
+			return -EINVAL;
+		if (!(atomic_read(&mm->membarrier_state) &
+		      MEMBARRIER_STATE_PRIVATE_EXPEDITED_SYNC_CORE_READY))
+			return -EPERM;
+		ipi_func = ipi_sync_core;
+	} else if (flags == MEMBARRIER_FLAG_RSEQ) {
+		if (!IS_ENABLED(CONFIG_RSEQ))
+			return -EINVAL;
+		if (!(atomic_read(&mm->membarrier_state) &
+		      MEMBARRIER_STATE_PRIVATE_EXPEDITED_RSEQ_READY))
+			return -EPERM;
+		ipi_func = ipi_rseq;
+	} else {
+		WARN_ON_ONCE(flags);
+		if (!(atomic_read(&mm->membarrier_state) &
+		      MEMBARRIER_STATE_PRIVATE_EXPEDITED_READY))
+			return -EPERM;
+	}
+
+	if (flags != MEMBARRIER_FLAG_SYNC_CORE &&
+	    (atomic_read(&mm->mm_users) == 1 || num_online_cpus() == 1))
+		return 0;
+
+	/*
+	 * Matches memory barriers around rq->curr modification in
+	 * scheduler.
+	 */
+	smp_mb();	/* system call entry is not a mb. */
+
+	if (cpu_id < 0 && !zalloc_cpumask_var(&tmpmask, GFP_KERNEL))
+		return -ENOMEM;
+
+	cpus_read_lock();
+
+	if (cpu_id >= 0) {
+		struct task_struct *p;
+
+		if (cpu_id >= nr_cpu_ids || !cpu_online(cpu_id))
+			goto out;
+		rcu_read_lock();
+		p = rcu_dereference(cpu_rq(cpu_id)->curr);
+		if (!p || p->mm != mm) {
+			rcu_read_unlock();
+			goto out;
+		}
+		rcu_read_unlock();
+	} else {
+		int cpu;
+
+		rcu_read_lock();
+		for_each_online_cpu(cpu) {
+			struct task_struct *p;
+
+			p = rcu_dereference(cpu_rq(cpu)->curr);
+			if (p && p->mm == mm)
+				__cpumask_set_cpu(cpu, tmpmask);
+		}
+		rcu_read_unlock();
+	}
+
+	if (cpu_id >= 0) {
+		/*
+		 * smp_call_function_single() will call ipi_func() if cpu_id
+		 * is the calling CPU.
+		 */
+		smp_call_function_single(cpu_id, ipi_func, NULL, 1);
+	} else {
+		/*
+		 * For regular membarrier, we can save a few cycles by
+		 * skipping the current cpu -- we're about to do smp_mb()
+		 * below, and if we migrate to a different cpu, this cpu
+		 * and the new cpu will execute a full barrier in the
+		 * scheduler.
+		 *
+		 * For SYNC_CORE, we do need a barrier on the current cpu --
+		 * otherwise, if we are migrated and replaced by a different
+		 * task in the same mm just before, during, or after
+		 * membarrier, we will end up with some thread in the mm
+		 * running without a core sync.
+		 *
+		 * For RSEQ, don't rseq_preempt() the caller.  User code
+		 * is not supposed to issue syscalls at all from inside an
+		 * rseq critical section.
+		 */
+		if (flags != MEMBARRIER_FLAG_SYNC_CORE) {
+			preempt_disable();
+			smp_call_function_many(tmpmask, ipi_func, NULL, true);
+			preempt_enable();
+		} else {
+			on_each_cpu_mask(tmpmask, ipi_func, NULL, true);
+		}
+	}
+
+out:
+	if (cpu_id < 0)
+		free_cpumask_var(tmpmask);
+	cpus_read_unlock();
+
+	/*
+	 * Memory barrier on the caller thread _after_ we finished
+	 * waiting for the last IPI. Matches memory barriers around
+	 * rq->curr modification in scheduler.
+	 */
+	smp_mb();	/* exit from system call is not a mb */
+
+	return 0;
+}
+
+static int sync_runqueues_membarrier_state(struct mm_struct *mm)
+{
+	int membarrier_state = atomic_read(&mm->membarrier_state);
+	cpumask_var_t tmpmask;
+	int cpu;
+
+	if (atomic_read(&mm->mm_users) == 1 || num_online_cpus() == 1) {
+		this_cpu_write(runqueues.membarrier_state, membarrier_state);
+
+		/*
+		 * For single mm user, we can simply issue a memory barrier
+		 * after setting MEMBARRIER_STATE_GLOBAL_EXPEDITED in the
+		 * mm and in the current runqueue to guarantee that no memory
+		 * access following registration is reordered before
+		 * registration.
+		 */
+		smp_mb();
+		return 0;
+	}
+
+	if (!zalloc_cpumask_var(&tmpmask, GFP_KERNEL))
+		return -ENOMEM;
+
+	/*
+	 * For mm with multiple users, we need to ensure all future
+	 * scheduler executions will observe @mm's new membarrier
+	 * state.
+	 */
+	synchronize_rcu();
+
+	/*
+	 * For each cpu runqueue, if the task's mm match @mm, ensure that all
+	 * @mm's membarrier state set bits are also set in the runqueue's
+	 * membarrier state. This ensures that a runqueue scheduling
+	 * between threads which are users of @mm has its membarrier state
+	 * updated.
+	 */
+	cpus_read_lock();
+	rcu_read_lock();
+	for_each_online_cpu(cpu) {
+		struct rq *rq = cpu_rq(cpu);
+		struct task_struct *p;
+
+		p = rcu_dereference(rq->curr);
+		if (p && p->mm == mm)
+			__cpumask_set_cpu(cpu, tmpmask);
+	}
+	rcu_read_unlock();
+
+	on_each_cpu_mask(tmpmask, ipi_sync_rq_state, mm, true);
+
+	free_cpumask_var(tmpmask);
+	cpus_read_unlock();
+
+	return 0;
+}
+
+static int membarrier_register_global_expedited(void)
+{
+	struct task_struct *p = current;
+	struct mm_struct *mm = p->mm;
+	int ret;
+
+	if (atomic_read(&mm->membarrier_state) &
+	    MEMBARRIER_STATE_GLOBAL_EXPEDITED_READY)
+		return 0;
+	atomic_or(MEMBARRIER_STATE_GLOBAL_EXPEDITED, &mm->membarrier_state);
+	ret = sync_runqueues_membarrier_state(mm);
+	if (ret)
+		return ret;
+	atomic_or(MEMBARRIER_STATE_GLOBAL_EXPEDITED_READY,
+		  &mm->membarrier_state);
+
+	return 0;
+}
+
+static int membarrier_register_private_expedited(int flags)
+{
+	struct task_struct *p = current;
+	struct mm_struct *mm = p->mm;
+	int ready_state = MEMBARRIER_STATE_PRIVATE_EXPEDITED_READY,
+	    set_state = MEMBARRIER_STATE_PRIVATE_EXPEDITED,
+	    ret;
+
+	if (flags == MEMBARRIER_FLAG_SYNC_CORE) {
+		if (!IS_ENABLED(CONFIG_ARCH_HAS_MEMBARRIER_SYNC_CORE))
+			return -EINVAL;
+		ready_state =
+			MEMBARRIER_STATE_PRIVATE_EXPEDITED_SYNC_CORE_READY;
+	} else if (flags == MEMBARRIER_FLAG_RSEQ) {
+		if (!IS_ENABLED(CONFIG_RSEQ))
+			return -EINVAL;
+		ready_state =
+			MEMBARRIER_STATE_PRIVATE_EXPEDITED_RSEQ_READY;
+	} else {
+		WARN_ON_ONCE(flags);
+	}
+
+	/*
+	 * We need to consider threads belonging to different thread
+	 * groups, which use the same mm. (CLONE_VM but not
+	 * CLONE_THREAD).
+	 */
+	if ((atomic_read(&mm->membarrier_state) & ready_state) == ready_state)
+		return 0;
+	if (flags & MEMBARRIER_FLAG_SYNC_CORE)
+		set_state |= MEMBARRIER_STATE_PRIVATE_EXPEDITED_SYNC_CORE;
+	if (flags & MEMBARRIER_FLAG_RSEQ)
+		set_state |= MEMBARRIER_STATE_PRIVATE_EXPEDITED_RSEQ;
+	atomic_or(set_state, &mm->membarrier_state);
+	ret = sync_runqueues_membarrier_state(mm);
+	if (ret)
+		return ret;
+	atomic_or(ready_state, &mm->membarrier_state);
+
+	return 0;
+}
+
+static int membarrier_get_registrations(void)
+{
+	struct task_struct *p = current;
+	struct mm_struct *mm = p->mm;
+	int registrations_mask = 0, membarrier_state, i;
+	static const int states[] = {
+		MEMBARRIER_STATE_GLOBAL_EXPEDITED |
+			MEMBARRIER_STATE_GLOBAL_EXPEDITED_READY,
+		MEMBARRIER_STATE_PRIVATE_EXPEDITED |
+			MEMBARRIER_STATE_PRIVATE_EXPEDITED_READY,
+		MEMBARRIER_STATE_PRIVATE_EXPEDITED_SYNC_CORE |
+			MEMBARRIER_STATE_PRIVATE_EXPEDITED_SYNC_CORE_READY,
+		MEMBARRIER_STATE_PRIVATE_EXPEDITED_RSEQ |
+			MEMBARRIER_STATE_PRIVATE_EXPEDITED_RSEQ_READY
+	};
+	static const int registration_cmds[] = {
+		MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED,
+		MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED,
+		MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_SYNC_CORE,
+		MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ
+	};
+	BUILD_BUG_ON(ARRAY_SIZE(states) != ARRAY_SIZE(registration_cmds));
+
+	membarrier_state = atomic_read(&mm->membarrier_state);
+	for (i = 0; i < ARRAY_SIZE(states); ++i) {
+		if (membarrier_state & states[i]) {
+			registrations_mask |= registration_cmds[i];
+			membarrier_state &= ~states[i];
+		}
+	}
+	WARN_ON_ONCE(membarrier_state != 0);
+	return registrations_mask;
+}
+
+/**
+ * sys_membarrier - issue memory barriers on a set of threads
+ * @cmd:    Takes command values defined in enum membarrier_cmd.
+ * @flags:  Currently needs to be 0 for all commands other than
+ *          MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ: in the latter
+ *          case it can be MEMBARRIER_CMD_FLAG_CPU, indicating that @cpu_id
+ *          contains the CPU on which to interrupt (= restart)
+ *          the RSEQ critical section.
+ * @cpu_id: if @flags == MEMBARRIER_CMD_FLAG_CPU, indicates the cpu on which
+ *          RSEQ CS should be interrupted (@cmd must be
+ *          MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ).
+ *
+ * If this system call is not implemented, -ENOSYS is returned. If the
+ * command specified does not exist, not available on the running
+ * kernel, or if the command argument is invalid, this system call
+ * returns -EINVAL. For a given command, with flags argument set to 0,
+ * if this system call returns -ENOSYS or -EINVAL, it is guaranteed to
+ * always return the same value until reboot. In addition, it can return
+ * -ENOMEM if there is not enough memory available to perform the system
+ * call.
+ *
+ * All memory accesses performed in program order from each targeted thread
+ * is guaranteed to be ordered with respect to sys_membarrier(). If we use
+ * the semantic "barrier()" to represent a compiler barrier forcing memory
+ * accesses to be performed in program order across the barrier, and
+ * smp_mb() to represent explicit memory barriers forcing full memory
+ * ordering across the barrier, we have the following ordering table for
+ * each pair of barrier(), sys_membarrier() and smp_mb():
+ *
+ * The pair ordering is detailed as (O: ordered, X: not ordered):
+ *
+ *                        barrier()   smp_mb() sys_membarrier()
+ *        barrier()          X           X            O
+ *        smp_mb()           X           O            O
+ *        sys_membarrier()   O           O            O
+ */
+SYSCALL_DEFINE3(membarrier, int, cmd, unsigned int, flags, int, cpu_id)
+{
+	switch (cmd) {
+	case MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ:
+		if (unlikely(flags && flags != MEMBARRIER_CMD_FLAG_CPU))
+			return -EINVAL;
+		break;
+	default:
+		if (unlikely(flags))
+			return -EINVAL;
+	}
+
+	if (!(flags & MEMBARRIER_CMD_FLAG_CPU))
+		cpu_id = -1;
+
+	switch (cmd) {
+	case MEMBARRIER_CMD_QUERY:
+	{
+		int cmd_mask = MEMBARRIER_CMD_BITMASK;
+
+		if (tick_nohz_full_enabled())
+			cmd_mask &= ~MEMBARRIER_CMD_GLOBAL;
+		return cmd_mask;
+	}
+	case MEMBARRIER_CMD_GLOBAL:
+		/* MEMBARRIER_CMD_GLOBAL is not compatible with nohz_full. */
+		if (tick_nohz_full_enabled())
+			return -EINVAL;
+		if (num_online_cpus() > 1)
+			synchronize_rcu();
+		return 0;
+	case MEMBARRIER_CMD_GLOBAL_EXPEDITED:
+		return membarrier_global_expedited();
+	case MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED:
+		return membarrier_register_global_expedited();
+	case MEMBARRIER_CMD_PRIVATE_EXPEDITED:
+		return membarrier_private_expedited(0, cpu_id);
+	case MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED:
+		return membarrier_register_private_expedited(0);
+	case MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE:
+		return membarrier_private_expedited(MEMBARRIER_FLAG_SYNC_CORE, cpu_id);
+	case MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_SYNC_CORE:
+		return membarrier_register_private_expedited(MEMBARRIER_FLAG_SYNC_CORE);
+	case MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ:
+		return membarrier_private_expedited(MEMBARRIER_FLAG_RSEQ, cpu_id);
+	case MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ:
+		return membarrier_register_private_expedited(MEMBARRIER_FLAG_RSEQ);
+	case MEMBARRIER_CMD_GET_REGISTRATIONS:
+		return membarrier_get_registrations();
+	default:
+		return -EINVAL;
+	}
+}
diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c
new file mode 100644
index 0000000000..0f31076826
--- /dev/null
+++ b/kernel/sched/pelt.c
@@ -0,0 +1,469 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Per Entity Load Tracking
+ *
+ *  Copyright (C) 2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ *  Interactivity improvements by Mike Galbraith
+ *  (C) 2007 Mike Galbraith <efault@gmx.de>
+ *
+ *  Various enhancements by Dmitry Adamushko.
+ *  (C) 2007 Dmitry Adamushko <dmitry.adamushko@gmail.com>
+ *
+ *  Group scheduling enhancements by Srivatsa Vaddagiri
+ *  Copyright IBM Corporation, 2007
+ *  Author: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
+ *
+ *  Scaled math optimizations by Thomas Gleixner
+ *  Copyright (C) 2007, Thomas Gleixner <tglx@linutronix.de>
+ *
+ *  Adaptive scheduling granularity, math enhancements by Peter Zijlstra
+ *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
+ *
+ *  Move PELT related code from fair.c into this pelt.c file
+ *  Author: Vincent Guittot <vincent.guittot@linaro.org>
+ */
+
+/*
+ * Approximate:
+ *   val * y^n,    where y^32 ~= 0.5 (~1 scheduling period)
+ */
+static u64 decay_load(u64 val, u64 n)
+{
+	unsigned int local_n;
+
+	if (unlikely(n > LOAD_AVG_PERIOD * 63))
+		return 0;
+
+	/* after bounds checking we can collapse to 32-bit */
+	local_n = n;
+
+	/*
+	 * As y^PERIOD = 1/2, we can combine
+	 *    y^n = 1/2^(n/PERIOD) * y^(n%PERIOD)
+	 * With a look-up table which covers y^n (n<PERIOD)
+	 *
+	 * To achieve constant time decay_load.
+	 */
+	if (unlikely(local_n >= LOAD_AVG_PERIOD)) {
+		val >>= local_n / LOAD_AVG_PERIOD;
+		local_n %= LOAD_AVG_PERIOD;
+	}
+
+	val = mul_u64_u32_shr(val, runnable_avg_yN_inv[local_n], 32);
+	return val;
+}
+
+static u32 __accumulate_pelt_segments(u64 periods, u32 d1, u32 d3)
+{
+	u32 c1, c2, c3 = d3; /* y^0 == 1 */
+
+	/*
+	 * c1 = d1 y^p
+	 */
+	c1 = decay_load((u64)d1, periods);
+
+	/*
+	 *            p-1
+	 * c2 = 1024 \Sum y^n
+	 *            n=1
+	 *
+	 *              inf        inf
+	 *    = 1024 ( \Sum y^n - \Sum y^n - y^0 )
+	 *              n=0        n=p
+	 */
+	c2 = LOAD_AVG_MAX - decay_load(LOAD_AVG_MAX, periods) - 1024;
+
+	return c1 + c2 + c3;
+}
+
+/*
+ * Accumulate the three separate parts of the sum; d1 the remainder
+ * of the last (incomplete) period, d2 the span of full periods and d3
+ * the remainder of the (incomplete) current period.
+ *
+ *           d1          d2           d3
+ *           ^           ^            ^
+ *           |           |            |
+ *         |<->|<----------------->|<--->|
+ * ... |---x---|------| ... |------|-----x (now)
+ *
+ *                           p-1
+ * u' = (u + d1) y^p + 1024 \Sum y^n + d3 y^0
+ *                           n=1
+ *
+ *    = u y^p +					(Step 1)
+ *
+ *                     p-1
+ *      d1 y^p + 1024 \Sum y^n + d3 y^0		(Step 2)
+ *                     n=1
+ */
+static __always_inline u32
+accumulate_sum(u64 delta, struct sched_avg *sa,
+	       unsigned long load, unsigned long runnable, int running)
+{
+	u32 contrib = (u32)delta; /* p == 0 -> delta < 1024 */
+	u64 periods;
+
+	delta += sa->period_contrib;
+	periods = delta / 1024; /* A period is 1024us (~1ms) */
+
+	/*
+	 * Step 1: decay old *_sum if we crossed period boundaries.
+	 */
+	if (periods) {
+		sa->load_sum = decay_load(sa->load_sum, periods);
+		sa->runnable_sum =
+			decay_load(sa->runnable_sum, periods);
+		sa->util_sum = decay_load((u64)(sa->util_sum), periods);
+
+		/*
+		 * Step 2
+		 */
+		delta %= 1024;
+		if (load) {
+			/*
+			 * This relies on the:
+			 *
+			 * if (!load)
+			 *	runnable = running = 0;
+			 *
+			 * clause from ___update_load_sum(); this results in
+			 * the below usage of @contrib to disappear entirely,
+			 * so no point in calculating it.
+			 */
+			contrib = __accumulate_pelt_segments(periods,
+					1024 - sa->period_contrib, delta);
+		}
+	}
+	sa->period_contrib = delta;
+
+	if (load)
+		sa->load_sum += load * contrib;
+	if (runnable)
+		sa->runnable_sum += runnable * contrib << SCHED_CAPACITY_SHIFT;
+	if (running)
+		sa->util_sum += contrib << SCHED_CAPACITY_SHIFT;
+
+	return periods;
+}
+
+/*
+ * We can represent the historical contribution to runnable average as the
+ * coefficients of a geometric series.  To do this we sub-divide our runnable
+ * history into segments of approximately 1ms (1024us); label the segment that
+ * occurred N-ms ago p_N, with p_0 corresponding to the current period, e.g.
+ *
+ * [<- 1024us ->|<- 1024us ->|<- 1024us ->| ...
+ *      p0            p1           p2
+ *     (now)       (~1ms ago)  (~2ms ago)
+ *
+ * Let u_i denote the fraction of p_i that the entity was runnable.
+ *
+ * We then designate the fractions u_i as our co-efficients, yielding the
+ * following representation of historical load:
+ *   u_0 + u_1*y + u_2*y^2 + u_3*y^3 + ...
+ *
+ * We choose y based on the with of a reasonably scheduling period, fixing:
+ *   y^32 = 0.5
+ *
+ * This means that the contribution to load ~32ms ago (u_32) will be weighted
+ * approximately half as much as the contribution to load within the last ms
+ * (u_0).
+ *
+ * When a period "rolls over" and we have new u_0`, multiplying the previous
+ * sum again by y is sufficient to update:
+ *   load_avg = u_0` + y*(u_0 + u_1*y + u_2*y^2 + ... )
+ *            = u_0 + u_1*y + u_2*y^2 + ... [re-labeling u_i --> u_{i+1}]
+ */
+static __always_inline int
+___update_load_sum(u64 now, struct sched_avg *sa,
+		  unsigned long load, unsigned long runnable, int running)
+{
+	u64 delta;
+
+	delta = now - sa->last_update_time;
+	/*
+	 * This should only happen when time goes backwards, which it
+	 * unfortunately does during sched clock init when we swap over to TSC.
+	 */
+	if ((s64)delta < 0) {
+		sa->last_update_time = now;
+		return 0;
+	}
+
+	/*
+	 * Use 1024ns as the unit of measurement since it's a reasonable
+	 * approximation of 1us and fast to compute.
+	 */
+	delta >>= 10;
+	if (!delta)
+		return 0;
+
+	sa->last_update_time += delta << 10;
+
+	/*
+	 * running is a subset of runnable (weight) so running can't be set if
+	 * runnable is clear. But there are some corner cases where the current
+	 * se has been already dequeued but cfs_rq->curr still points to it.
+	 * This means that weight will be 0 but not running for a sched_entity
+	 * but also for a cfs_rq if the latter becomes idle. As an example,
+	 * this happens during idle_balance() which calls
+	 * update_blocked_averages().
+	 *
+	 * Also see the comment in accumulate_sum().
+	 */
+	if (!load)
+		runnable = running = 0;
+
+	/*
+	 * Now we know we crossed measurement unit boundaries. The *_avg
+	 * accrues by two steps:
+	 *
+	 * Step 1: accumulate *_sum since last_update_time. If we haven't
+	 * crossed period boundaries, finish.
+	 */
+	if (!accumulate_sum(delta, sa, load, runnable, running))
+		return 0;
+
+	return 1;
+}
+
+/*
+ * When syncing *_avg with *_sum, we must take into account the current
+ * position in the PELT segment otherwise the remaining part of the segment
+ * will be considered as idle time whereas it's not yet elapsed and this will
+ * generate unwanted oscillation in the range [1002..1024[.
+ *
+ * The max value of *_sum varies with the position in the time segment and is
+ * equals to :
+ *
+ *   LOAD_AVG_MAX*y + sa->period_contrib
+ *
+ * which can be simplified into:
+ *
+ *   LOAD_AVG_MAX - 1024 + sa->period_contrib
+ *
+ * because LOAD_AVG_MAX*y == LOAD_AVG_MAX-1024
+ *
+ * The same care must be taken when a sched entity is added, updated or
+ * removed from a cfs_rq and we need to update sched_avg. Scheduler entities
+ * and the cfs rq, to which they are attached, have the same position in the
+ * time segment because they use the same clock. This means that we can use
+ * the period_contrib of cfs_rq when updating the sched_avg of a sched_entity
+ * if it's more convenient.
+ */
+static __always_inline void
+___update_load_avg(struct sched_avg *sa, unsigned long load)
+{
+	u32 divider = get_pelt_divider(sa);
+
+	/*
+	 * Step 2: update *_avg.
+	 */
+	sa->load_avg = div_u64(load * sa->load_sum, divider);
+	sa->runnable_avg = div_u64(sa->runnable_sum, divider);
+	WRITE_ONCE(sa->util_avg, sa->util_sum / divider);
+}
+
+/*
+ * sched_entity:
+ *
+ *   task:
+ *     se_weight()   = se->load.weight
+ *     se_runnable() = !!on_rq
+ *
+ *   group: [ see update_cfs_group() ]
+ *     se_weight()   = tg->weight * grq->load_avg / tg->load_avg
+ *     se_runnable() = grq->h_nr_running
+ *
+ *   runnable_sum = se_runnable() * runnable = grq->runnable_sum
+ *   runnable_avg = runnable_sum
+ *
+ *   load_sum := runnable
+ *   load_avg = se_weight(se) * load_sum
+ *
+ * cfq_rq:
+ *
+ *   runnable_sum = \Sum se->avg.runnable_sum
+ *   runnable_avg = \Sum se->avg.runnable_avg
+ *
+ *   load_sum = \Sum se_weight(se) * se->avg.load_sum
+ *   load_avg = \Sum se->avg.load_avg
+ */
+
+int __update_load_avg_blocked_se(u64 now, struct sched_entity *se)
+{
+	if (___update_load_sum(now, &se->avg, 0, 0, 0)) {
+		___update_load_avg(&se->avg, se_weight(se));
+		trace_pelt_se_tp(se);
+		return 1;
+	}
+
+	return 0;
+}
+
+int __update_load_avg_se(u64 now, struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	if (___update_load_sum(now, &se->avg, !!se->on_rq, se_runnable(se),
+				cfs_rq->curr == se)) {
+
+		___update_load_avg(&se->avg, se_weight(se));
+		cfs_se_util_change(&se->avg);
+		trace_pelt_se_tp(se);
+		return 1;
+	}
+
+	return 0;
+}
+
+int __update_load_avg_cfs_rq(u64 now, struct cfs_rq *cfs_rq)
+{
+	if (___update_load_sum(now, &cfs_rq->avg,
+				scale_load_down(cfs_rq->load.weight),
+				cfs_rq->h_nr_running,
+				cfs_rq->curr != NULL)) {
+
+		___update_load_avg(&cfs_rq->avg, 1);
+		trace_pelt_cfs_tp(cfs_rq);
+		return 1;
+	}
+
+	return 0;
+}
+
+/*
+ * rt_rq:
+ *
+ *   util_sum = \Sum se->avg.util_sum but se->avg.util_sum is not tracked
+ *   util_sum = cpu_scale * load_sum
+ *   runnable_sum = util_sum
+ *
+ *   load_avg and runnable_avg are not supported and meaningless.
+ *
+ */
+
+int update_rt_rq_load_avg(u64 now, struct rq *rq, int running)
+{
+	if (___update_load_sum(now, &rq->avg_rt,
+				running,
+				running,
+				running)) {
+
+		___update_load_avg(&rq->avg_rt, 1);
+		trace_pelt_rt_tp(rq);
+		return 1;
+	}
+
+	return 0;
+}
+
+/*
+ * dl_rq:
+ *
+ *   util_sum = \Sum se->avg.util_sum but se->avg.util_sum is not tracked
+ *   util_sum = cpu_scale * load_sum
+ *   runnable_sum = util_sum
+ *
+ *   load_avg and runnable_avg are not supported and meaningless.
+ *
+ */
+
+int update_dl_rq_load_avg(u64 now, struct rq *rq, int running)
+{
+	if (___update_load_sum(now, &rq->avg_dl,
+				running,
+				running,
+				running)) {
+
+		___update_load_avg(&rq->avg_dl, 1);
+		trace_pelt_dl_tp(rq);
+		return 1;
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_SCHED_THERMAL_PRESSURE
+/*
+ * thermal:
+ *
+ *   load_sum = \Sum se->avg.load_sum but se->avg.load_sum is not tracked
+ *
+ *   util_avg and runnable_load_avg are not supported and meaningless.
+ *
+ * Unlike rt/dl utilization tracking that track time spent by a cpu
+ * running a rt/dl task through util_avg, the average thermal pressure is
+ * tracked through load_avg. This is because thermal pressure signal is
+ * time weighted "delta" capacity unlike util_avg which is binary.
+ * "delta capacity" =  actual capacity  -
+ *			capped capacity a cpu due to a thermal event.
+ */
+
+int update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity)
+{
+	if (___update_load_sum(now, &rq->avg_thermal,
+			       capacity,
+			       capacity,
+			       capacity)) {
+		___update_load_avg(&rq->avg_thermal, 1);
+		trace_pelt_thermal_tp(rq);
+		return 1;
+	}
+
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
+/*
+ * irq:
+ *
+ *   util_sum = \Sum se->avg.util_sum but se->avg.util_sum is not tracked
+ *   util_sum = cpu_scale * load_sum
+ *   runnable_sum = util_sum
+ *
+ *   load_avg and runnable_avg are not supported and meaningless.
+ *
+ */
+
+int update_irq_load_avg(struct rq *rq, u64 running)
+{
+	int ret = 0;
+
+	/*
+	 * We can't use clock_pelt because irq time is not accounted in
+	 * clock_task. Instead we directly scale the running time to
+	 * reflect the real amount of computation
+	 */
+	running = cap_scale(running, arch_scale_freq_capacity(cpu_of(rq)));
+	running = cap_scale(running, arch_scale_cpu_capacity(cpu_of(rq)));
+
+	/*
+	 * We know the time that has been used by interrupt since last update
+	 * but we don't when. Let be pessimistic and assume that interrupt has
+	 * happened just before the update. This is not so far from reality
+	 * because interrupt will most probably wake up task and trig an update
+	 * of rq clock during which the metric is updated.
+	 * We start to decay with normal context time and then we add the
+	 * interrupt context time.
+	 * We can safely remove running from rq->clock because
+	 * rq->clock += delta with delta >= running
+	 */
+	ret = ___update_load_sum(rq->clock - running, &rq->avg_irq,
+				0,
+				0,
+				0);
+	ret += ___update_load_sum(rq->clock, &rq->avg_irq,
+				1,
+				1,
+				1);
+
+	if (ret) {
+		___update_load_avg(&rq->avg_irq, 1);
+		trace_pelt_irq_tp(rq);
+	}
+
+	return ret;
+}
+#endif
diff --git a/kernel/sched/pelt.h b/kernel/sched/pelt.h
new file mode 100644
index 0000000000..3a0e0dc287
--- /dev/null
+++ b/kernel/sched/pelt.h
@@ -0,0 +1,235 @@
+#ifdef CONFIG_SMP
+#include "sched-pelt.h"
+
+int __update_load_avg_blocked_se(u64 now, struct sched_entity *se);
+int __update_load_avg_se(u64 now, struct cfs_rq *cfs_rq, struct sched_entity *se);
+int __update_load_avg_cfs_rq(u64 now, struct cfs_rq *cfs_rq);
+int update_rt_rq_load_avg(u64 now, struct rq *rq, int running);
+int update_dl_rq_load_avg(u64 now, struct rq *rq, int running);
+
+#ifdef CONFIG_SCHED_THERMAL_PRESSURE
+int update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity);
+
+static inline u64 thermal_load_avg(struct rq *rq)
+{
+	return READ_ONCE(rq->avg_thermal.load_avg);
+}
+#else
+static inline int
+update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity)
+{
+	return 0;
+}
+
+static inline u64 thermal_load_avg(struct rq *rq)
+{
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
+int update_irq_load_avg(struct rq *rq, u64 running);
+#else
+static inline int
+update_irq_load_avg(struct rq *rq, u64 running)
+{
+	return 0;
+}
+#endif
+
+#define PELT_MIN_DIVIDER	(LOAD_AVG_MAX - 1024)
+
+static inline u32 get_pelt_divider(struct sched_avg *avg)
+{
+	return PELT_MIN_DIVIDER + avg->period_contrib;
+}
+
+static inline void cfs_se_util_change(struct sched_avg *avg)
+{
+	unsigned int enqueued;
+
+	if (!sched_feat(UTIL_EST))
+		return;
+
+	/* Avoid store if the flag has been already reset */
+	enqueued = avg->util_est.enqueued;
+	if (!(enqueued & UTIL_AVG_UNCHANGED))
+		return;
+
+	/* Reset flag to report util_avg has been updated */
+	enqueued &= ~UTIL_AVG_UNCHANGED;
+	WRITE_ONCE(avg->util_est.enqueued, enqueued);
+}
+
+static inline u64 rq_clock_pelt(struct rq *rq)
+{
+	lockdep_assert_rq_held(rq);
+	assert_clock_updated(rq);
+
+	return rq->clock_pelt - rq->lost_idle_time;
+}
+
+/* The rq is idle, we can sync to clock_task */
+static inline void _update_idle_rq_clock_pelt(struct rq *rq)
+{
+	rq->clock_pelt  = rq_clock_task(rq);
+
+	u64_u32_store(rq->clock_idle, rq_clock(rq));
+	/* Paired with smp_rmb in migrate_se_pelt_lag() */
+	smp_wmb();
+	u64_u32_store(rq->clock_pelt_idle, rq_clock_pelt(rq));
+}
+
+/*
+ * The clock_pelt scales the time to reflect the effective amount of
+ * computation done during the running delta time but then sync back to
+ * clock_task when rq is idle.
+ *
+ *
+ * absolute time   | 1| 2| 3| 4| 5| 6| 7| 8| 9|10|11|12|13|14|15|16
+ * @ max capacity  ------******---------------******---------------
+ * @ half capacity ------************---------************---------
+ * clock pelt      | 1| 2|    3|    4| 7| 8| 9|   10|   11|14|15|16
+ *
+ */
+static inline void update_rq_clock_pelt(struct rq *rq, s64 delta)
+{
+	if (unlikely(is_idle_task(rq->curr))) {
+		_update_idle_rq_clock_pelt(rq);
+		return;
+	}
+
+	/*
+	 * When a rq runs at a lower compute capacity, it will need
+	 * more time to do the same amount of work than at max
+	 * capacity. In order to be invariant, we scale the delta to
+	 * reflect how much work has been really done.
+	 * Running longer results in stealing idle time that will
+	 * disturb the load signal compared to max capacity. This
+	 * stolen idle time will be automatically reflected when the
+	 * rq will be idle and the clock will be synced with
+	 * rq_clock_task.
+	 */
+
+	/*
+	 * Scale the elapsed time to reflect the real amount of
+	 * computation
+	 */
+	delta = cap_scale(delta, arch_scale_cpu_capacity(cpu_of(rq)));
+	delta = cap_scale(delta, arch_scale_freq_capacity(cpu_of(rq)));
+
+	rq->clock_pelt += delta;
+}
+
+/*
+ * When rq becomes idle, we have to check if it has lost idle time
+ * because it was fully busy. A rq is fully used when the /Sum util_sum
+ * is greater or equal to:
+ * (LOAD_AVG_MAX - 1024 + rq->cfs.avg.period_contrib) << SCHED_CAPACITY_SHIFT;
+ * For optimization and computing rounding purpose, we don't take into account
+ * the position in the current window (period_contrib) and we use the higher
+ * bound of util_sum to decide.
+ */
+static inline void update_idle_rq_clock_pelt(struct rq *rq)
+{
+	u32 divider = ((LOAD_AVG_MAX - 1024) << SCHED_CAPACITY_SHIFT) - LOAD_AVG_MAX;
+	u32 util_sum = rq->cfs.avg.util_sum;
+	util_sum += rq->avg_rt.util_sum;
+	util_sum += rq->avg_dl.util_sum;
+
+	/*
+	 * Reflecting stolen time makes sense only if the idle
+	 * phase would be present at max capacity. As soon as the
+	 * utilization of a rq has reached the maximum value, it is
+	 * considered as an always running rq without idle time to
+	 * steal. This potential idle time is considered as lost in
+	 * this case. We keep track of this lost idle time compare to
+	 * rq's clock_task.
+	 */
+	if (util_sum >= divider)
+		rq->lost_idle_time += rq_clock_task(rq) - rq->clock_pelt;
+
+	_update_idle_rq_clock_pelt(rq);
+}
+
+#ifdef CONFIG_CFS_BANDWIDTH
+static inline void update_idle_cfs_rq_clock_pelt(struct cfs_rq *cfs_rq)
+{
+	u64 throttled;
+
+	if (unlikely(cfs_rq->throttle_count))
+		throttled = U64_MAX;
+	else
+		throttled = cfs_rq->throttled_clock_pelt_time;
+
+	u64_u32_store(cfs_rq->throttled_pelt_idle, throttled);
+}
+
+/* rq->task_clock normalized against any time this cfs_rq has spent throttled */
+static inline u64 cfs_rq_clock_pelt(struct cfs_rq *cfs_rq)
+{
+	if (unlikely(cfs_rq->throttle_count))
+		return cfs_rq->throttled_clock_pelt - cfs_rq->throttled_clock_pelt_time;
+
+	return rq_clock_pelt(rq_of(cfs_rq)) - cfs_rq->throttled_clock_pelt_time;
+}
+#else
+static inline void update_idle_cfs_rq_clock_pelt(struct cfs_rq *cfs_rq) { }
+static inline u64 cfs_rq_clock_pelt(struct cfs_rq *cfs_rq)
+{
+	return rq_clock_pelt(rq_of(cfs_rq));
+}
+#endif
+
+#else
+
+static inline int
+update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
+{
+	return 0;
+}
+
+static inline int
+update_rt_rq_load_avg(u64 now, struct rq *rq, int running)
+{
+	return 0;
+}
+
+static inline int
+update_dl_rq_load_avg(u64 now, struct rq *rq, int running)
+{
+	return 0;
+}
+
+static inline int
+update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity)
+{
+	return 0;
+}
+
+static inline u64 thermal_load_avg(struct rq *rq)
+{
+	return 0;
+}
+
+static inline int
+update_irq_load_avg(struct rq *rq, u64 running)
+{
+	return 0;
+}
+
+static inline u64 rq_clock_pelt(struct rq *rq)
+{
+	return rq_clock_task(rq);
+}
+
+static inline void
+update_rq_clock_pelt(struct rq *rq, s64 delta) { }
+
+static inline void
+update_idle_rq_clock_pelt(struct rq *rq) { }
+
+static inline void update_idle_cfs_rq_clock_pelt(struct cfs_rq *cfs_rq) { }
+#endif
+
+
diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
new file mode 100644
index 0000000000..1d0f634725
--- /dev/null
+++ b/kernel/sched/psi.c
@@ -0,0 +1,1665 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Pressure stall information for CPU, memory and IO
+ *
+ * Copyright (c) 2018 Facebook, Inc.
+ * Author: Johannes Weiner <hannes@cmpxchg.org>
+ *
+ * Polling support by Suren Baghdasaryan <surenb@google.com>
+ * Copyright (c) 2018 Google, Inc.
+ *
+ * When CPU, memory and IO are contended, tasks experience delays that
+ * reduce throughput and introduce latencies into the workload. Memory
+ * and IO contention, in addition, can cause a full loss of forward
+ * progress in which the CPU goes idle.
+ *
+ * This code aggregates individual task delays into resource pressure
+ * metrics that indicate problems with both workload health and
+ * resource utilization.
+ *
+ *			Model
+ *
+ * The time in which a task can execute on a CPU is our baseline for
+ * productivity. Pressure expresses the amount of time in which this
+ * potential cannot be realized due to resource contention.
+ *
+ * This concept of productivity has two components: the workload and
+ * the CPU. To measure the impact of pressure on both, we define two
+ * contention states for a resource: SOME and FULL.
+ *
+ * In the SOME state of a given resource, one or more tasks are
+ * delayed on that resource. This affects the workload's ability to
+ * perform work, but the CPU may still be executing other tasks.
+ *
+ * In the FULL state of a given resource, all non-idle tasks are
+ * delayed on that resource such that nobody is advancing and the CPU
+ * goes idle. This leaves both workload and CPU unproductive.
+ *
+ *	SOME = nr_delayed_tasks != 0
+ *	FULL = nr_delayed_tasks != 0 && nr_productive_tasks == 0
+ *
+ * What it means for a task to be productive is defined differently
+ * for each resource. For IO, productive means a running task. For
+ * memory, productive means a running task that isn't a reclaimer. For
+ * CPU, productive means an oncpu task.
+ *
+ * Naturally, the FULL state doesn't exist for the CPU resource at the
+ * system level, but exist at the cgroup level. At the cgroup level,
+ * FULL means all non-idle tasks in the cgroup are delayed on the CPU
+ * resource which is being used by others outside of the cgroup or
+ * throttled by the cgroup cpu.max configuration.
+ *
+ * The percentage of wallclock time spent in those compound stall
+ * states gives pressure numbers between 0 and 100 for each resource,
+ * where the SOME percentage indicates workload slowdowns and the FULL
+ * percentage indicates reduced CPU utilization:
+ *
+ *	%SOME = time(SOME) / period
+ *	%FULL = time(FULL) / period
+ *
+ *			Multiple CPUs
+ *
+ * The more tasks and available CPUs there are, the more work can be
+ * performed concurrently. This means that the potential that can go
+ * unrealized due to resource contention *also* scales with non-idle
+ * tasks and CPUs.
+ *
+ * Consider a scenario where 257 number crunching tasks are trying to
+ * run concurrently on 256 CPUs. If we simply aggregated the task
+ * states, we would have to conclude a CPU SOME pressure number of
+ * 100%, since *somebody* is waiting on a runqueue at all
+ * times. However, that is clearly not the amount of contention the
+ * workload is experiencing: only one out of 256 possible execution
+ * threads will be contended at any given time, or about 0.4%.
+ *
+ * Conversely, consider a scenario of 4 tasks and 4 CPUs where at any
+ * given time *one* of the tasks is delayed due to a lack of memory.
+ * Again, looking purely at the task state would yield a memory FULL
+ * pressure number of 0%, since *somebody* is always making forward
+ * progress. But again this wouldn't capture the amount of execution
+ * potential lost, which is 1 out of 4 CPUs, or 25%.
+ *
+ * To calculate wasted potential (pressure) with multiple processors,
+ * we have to base our calculation on the number of non-idle tasks in
+ * conjunction with the number of available CPUs, which is the number
+ * of potential execution threads. SOME becomes then the proportion of
+ * delayed tasks to possible threads, and FULL is the share of possible
+ * threads that are unproductive due to delays:
+ *
+ *	threads = min(nr_nonidle_tasks, nr_cpus)
+ *	   SOME = min(nr_delayed_tasks / threads, 1)
+ *	   FULL = (threads - min(nr_productive_tasks, threads)) / threads
+ *
+ * For the 257 number crunchers on 256 CPUs, this yields:
+ *
+ *	threads = min(257, 256)
+ *	   SOME = min(1 / 256, 1)             = 0.4%
+ *	   FULL = (256 - min(256, 256)) / 256 = 0%
+ *
+ * For the 1 out of 4 memory-delayed tasks, this yields:
+ *
+ *	threads = min(4, 4)
+ *	   SOME = min(1 / 4, 1)               = 25%
+ *	   FULL = (4 - min(3, 4)) / 4         = 25%
+ *
+ * [ Substitute nr_cpus with 1, and you can see that it's a natural
+ *   extension of the single-CPU model. ]
+ *
+ *			Implementation
+ *
+ * To assess the precise time spent in each such state, we would have
+ * to freeze the system on task changes and start/stop the state
+ * clocks accordingly. Obviously that doesn't scale in practice.
+ *
+ * Because the scheduler aims to distribute the compute load evenly
+ * among the available CPUs, we can track task state locally to each
+ * CPU and, at much lower frequency, extrapolate the global state for
+ * the cumulative stall times and the running averages.
+ *
+ * For each runqueue, we track:
+ *
+ *	   tSOME[cpu] = time(nr_delayed_tasks[cpu] != 0)
+ *	   tFULL[cpu] = time(nr_delayed_tasks[cpu] && !nr_productive_tasks[cpu])
+ *	tNONIDLE[cpu] = time(nr_nonidle_tasks[cpu] != 0)
+ *
+ * and then periodically aggregate:
+ *
+ *	tNONIDLE = sum(tNONIDLE[i])
+ *
+ *	   tSOME = sum(tSOME[i] * tNONIDLE[i]) / tNONIDLE
+ *	   tFULL = sum(tFULL[i] * tNONIDLE[i]) / tNONIDLE
+ *
+ *	   %SOME = tSOME / period
+ *	   %FULL = tFULL / period
+ *
+ * This gives us an approximation of pressure that is practical
+ * cost-wise, yet way more sensitive and accurate than periodic
+ * sampling of the aggregate task states would be.
+ */
+
+static int psi_bug __read_mostly;
+
+DEFINE_STATIC_KEY_FALSE(psi_disabled);
+static DEFINE_STATIC_KEY_TRUE(psi_cgroups_enabled);
+
+#ifdef CONFIG_PSI_DEFAULT_DISABLED
+static bool psi_enable;
+#else
+static bool psi_enable = true;
+#endif
+static int __init setup_psi(char *str)
+{
+	return kstrtobool(str, &psi_enable) == 0;
+}
+__setup("psi=", setup_psi);
+
+/* Running averages - we need to be higher-res than loadavg */
+#define PSI_FREQ	(2*HZ+1)	/* 2 sec intervals */
+#define EXP_10s		1677		/* 1/exp(2s/10s) as fixed-point */
+#define EXP_60s		1981		/* 1/exp(2s/60s) */
+#define EXP_300s	2034		/* 1/exp(2s/300s) */
+
+/* PSI trigger definitions */
+#define WINDOW_MAX_US 10000000	/* Max window size is 10s */
+#define UPDATES_PER_WINDOW 10	/* 10 updates per window */
+
+/* Sampling frequency in nanoseconds */
+static u64 psi_period __read_mostly;
+
+/* System-level pressure and stall tracking */
+static DEFINE_PER_CPU(struct psi_group_cpu, system_group_pcpu);
+struct psi_group psi_system = {
+	.pcpu = &system_group_pcpu,
+};
+
+static void psi_avgs_work(struct work_struct *work);
+
+static void poll_timer_fn(struct timer_list *t);
+
+static void group_init(struct psi_group *group)
+{
+	int cpu;
+
+	group->enabled = true;
+	for_each_possible_cpu(cpu)
+		seqcount_init(&per_cpu_ptr(group->pcpu, cpu)->seq);
+	group->avg_last_update = sched_clock();
+	group->avg_next_update = group->avg_last_update + psi_period;
+	mutex_init(&group->avgs_lock);
+
+	/* Init avg trigger-related members */
+	INIT_LIST_HEAD(&group->avg_triggers);
+	memset(group->avg_nr_triggers, 0, sizeof(group->avg_nr_triggers));
+	INIT_DELAYED_WORK(&group->avgs_work, psi_avgs_work);
+
+	/* Init rtpoll trigger-related members */
+	atomic_set(&group->rtpoll_scheduled, 0);
+	mutex_init(&group->rtpoll_trigger_lock);
+	INIT_LIST_HEAD(&group->rtpoll_triggers);
+	group->rtpoll_min_period = U32_MAX;
+	group->rtpoll_next_update = ULLONG_MAX;
+	init_waitqueue_head(&group->rtpoll_wait);
+	timer_setup(&group->rtpoll_timer, poll_timer_fn, 0);
+	rcu_assign_pointer(group->rtpoll_task, NULL);
+}
+
+void __init psi_init(void)
+{
+	if (!psi_enable) {
+		static_branch_enable(&psi_disabled);
+		static_branch_disable(&psi_cgroups_enabled);
+		return;
+	}
+
+	if (!cgroup_psi_enabled())
+		static_branch_disable(&psi_cgroups_enabled);
+
+	psi_period = jiffies_to_nsecs(PSI_FREQ);
+	group_init(&psi_system);
+}
+
+static bool test_state(unsigned int *tasks, enum psi_states state, bool oncpu)
+{
+	switch (state) {
+	case PSI_IO_SOME:
+		return unlikely(tasks[NR_IOWAIT]);
+	case PSI_IO_FULL:
+		return unlikely(tasks[NR_IOWAIT] && !tasks[NR_RUNNING]);
+	case PSI_MEM_SOME:
+		return unlikely(tasks[NR_MEMSTALL]);
+	case PSI_MEM_FULL:
+		return unlikely(tasks[NR_MEMSTALL] &&
+			tasks[NR_RUNNING] == tasks[NR_MEMSTALL_RUNNING]);
+	case PSI_CPU_SOME:
+		return unlikely(tasks[NR_RUNNING] > oncpu);
+	case PSI_CPU_FULL:
+		return unlikely(tasks[NR_RUNNING] && !oncpu);
+	case PSI_NONIDLE:
+		return tasks[NR_IOWAIT] || tasks[NR_MEMSTALL] ||
+			tasks[NR_RUNNING];
+	default:
+		return false;
+	}
+}
+
+static void get_recent_times(struct psi_group *group, int cpu,
+			     enum psi_aggregators aggregator, u32 *times,
+			     u32 *pchanged_states)
+{
+	struct psi_group_cpu *groupc = per_cpu_ptr(group->pcpu, cpu);
+	int current_cpu = raw_smp_processor_id();
+	unsigned int tasks[NR_PSI_TASK_COUNTS];
+	u64 now, state_start;
+	enum psi_states s;
+	unsigned int seq;
+	u32 state_mask;
+
+	*pchanged_states = 0;
+
+	/* Snapshot a coherent view of the CPU state */
+	do {
+		seq = read_seqcount_begin(&groupc->seq);
+		now = cpu_clock(cpu);
+		memcpy(times, groupc->times, sizeof(groupc->times));
+		state_mask = groupc->state_mask;
+		state_start = groupc->state_start;
+		if (cpu == current_cpu)
+			memcpy(tasks, groupc->tasks, sizeof(groupc->tasks));
+	} while (read_seqcount_retry(&groupc->seq, seq));
+
+	/* Calculate state time deltas against the previous snapshot */
+	for (s = 0; s < NR_PSI_STATES; s++) {
+		u32 delta;
+		/*
+		 * In addition to already concluded states, we also
+		 * incorporate currently active states on the CPU,
+		 * since states may last for many sampling periods.
+		 *
+		 * This way we keep our delta sampling buckets small
+		 * (u32) and our reported pressure close to what's
+		 * actually happening.
+		 */
+		if (state_mask & (1 << s))
+			times[s] += now - state_start;
+
+		delta = times[s] - groupc->times_prev[aggregator][s];
+		groupc->times_prev[aggregator][s] = times[s];
+
+		times[s] = delta;
+		if (delta)
+			*pchanged_states |= (1 << s);
+	}
+
+	/*
+	 * When collect_percpu_times() from the avgs_work, we don't want to
+	 * re-arm avgs_work when all CPUs are IDLE. But the current CPU running
+	 * this avgs_work is never IDLE, cause avgs_work can't be shut off.
+	 * So for the current CPU, we need to re-arm avgs_work only when
+	 * (NR_RUNNING > 1 || NR_IOWAIT > 0 || NR_MEMSTALL > 0), for other CPUs
+	 * we can just check PSI_NONIDLE delta.
+	 */
+	if (current_work() == &group->avgs_work.work) {
+		bool reschedule;
+
+		if (cpu == current_cpu)
+			reschedule = tasks[NR_RUNNING] +
+				     tasks[NR_IOWAIT] +
+				     tasks[NR_MEMSTALL] > 1;
+		else
+			reschedule = *pchanged_states & (1 << PSI_NONIDLE);
+
+		if (reschedule)
+			*pchanged_states |= PSI_STATE_RESCHEDULE;
+	}
+}
+
+static void calc_avgs(unsigned long avg[3], int missed_periods,
+		      u64 time, u64 period)
+{
+	unsigned long pct;
+
+	/* Fill in zeroes for periods of no activity */
+	if (missed_periods) {
+		avg[0] = calc_load_n(avg[0], EXP_10s, 0, missed_periods);
+		avg[1] = calc_load_n(avg[1], EXP_60s, 0, missed_periods);
+		avg[2] = calc_load_n(avg[2], EXP_300s, 0, missed_periods);
+	}
+
+	/* Sample the most recent active period */
+	pct = div_u64(time * 100, period);
+	pct *= FIXED_1;
+	avg[0] = calc_load(avg[0], EXP_10s, pct);
+	avg[1] = calc_load(avg[1], EXP_60s, pct);
+	avg[2] = calc_load(avg[2], EXP_300s, pct);
+}
+
+static void collect_percpu_times(struct psi_group *group,
+				 enum psi_aggregators aggregator,
+				 u32 *pchanged_states)
+{
+	u64 deltas[NR_PSI_STATES - 1] = { 0, };
+	unsigned long nonidle_total = 0;
+	u32 changed_states = 0;
+	int cpu;
+	int s;
+
+	/*
+	 * Collect the per-cpu time buckets and average them into a
+	 * single time sample that is normalized to wallclock time.
+	 *
+	 * For averaging, each CPU is weighted by its non-idle time in
+	 * the sampling period. This eliminates artifacts from uneven
+	 * loading, or even entirely idle CPUs.
+	 */
+	for_each_possible_cpu(cpu) {
+		u32 times[NR_PSI_STATES];
+		u32 nonidle;
+		u32 cpu_changed_states;
+
+		get_recent_times(group, cpu, aggregator, times,
+				&cpu_changed_states);
+		changed_states |= cpu_changed_states;
+
+		nonidle = nsecs_to_jiffies(times[PSI_NONIDLE]);
+		nonidle_total += nonidle;
+
+		for (s = 0; s < PSI_NONIDLE; s++)
+			deltas[s] += (u64)times[s] * nonidle;
+	}
+
+	/*
+	 * Integrate the sample into the running statistics that are
+	 * reported to userspace: the cumulative stall times and the
+	 * decaying averages.
+	 *
+	 * Pressure percentages are sampled at PSI_FREQ. We might be
+	 * called more often when the user polls more frequently than
+	 * that; we might be called less often when there is no task
+	 * activity, thus no data, and clock ticks are sporadic. The
+	 * below handles both.
+	 */
+
+	/* total= */
+	for (s = 0; s < NR_PSI_STATES - 1; s++)
+		group->total[aggregator][s] +=
+				div_u64(deltas[s], max(nonidle_total, 1UL));
+
+	if (pchanged_states)
+		*pchanged_states = changed_states;
+}
+
+/* Trigger tracking window manipulations */
+static void window_reset(struct psi_window *win, u64 now, u64 value,
+			 u64 prev_growth)
+{
+	win->start_time = now;
+	win->start_value = value;
+	win->prev_growth = prev_growth;
+}
+
+/*
+ * PSI growth tracking window update and growth calculation routine.
+ *
+ * This approximates a sliding tracking window by interpolating
+ * partially elapsed windows using historical growth data from the
+ * previous intervals. This minimizes memory requirements (by not storing
+ * all the intermediate values in the previous window) and simplifies
+ * the calculations. It works well because PSI signal changes only in
+ * positive direction and over relatively small window sizes the growth
+ * is close to linear.
+ */
+static u64 window_update(struct psi_window *win, u64 now, u64 value)
+{
+	u64 elapsed;
+	u64 growth;
+
+	elapsed = now - win->start_time;
+	growth = value - win->start_value;
+	/*
+	 * After each tracking window passes win->start_value and
+	 * win->start_time get reset and win->prev_growth stores
+	 * the average per-window growth of the previous window.
+	 * win->prev_growth is then used to interpolate additional
+	 * growth from the previous window assuming it was linear.
+	 */
+	if (elapsed > win->size)
+		window_reset(win, now, value, growth);
+	else {
+		u32 remaining;
+
+		remaining = win->size - elapsed;
+		growth += div64_u64(win->prev_growth * remaining, win->size);
+	}
+
+	return growth;
+}
+
+static u64 update_triggers(struct psi_group *group, u64 now, bool *update_total,
+						   enum psi_aggregators aggregator)
+{
+	struct psi_trigger *t;
+	u64 *total = group->total[aggregator];
+	struct list_head *triggers;
+	u64 *aggregator_total;
+	*update_total = false;
+
+	if (aggregator == PSI_AVGS) {
+		triggers = &group->avg_triggers;
+		aggregator_total = group->avg_total;
+	} else {
+		triggers = &group->rtpoll_triggers;
+		aggregator_total = group->rtpoll_total;
+	}
+
+	/*
+	 * On subsequent updates, calculate growth deltas and let
+	 * watchers know when their specified thresholds are exceeded.
+	 */
+	list_for_each_entry(t, triggers, node) {
+		u64 growth;
+		bool new_stall;
+
+		new_stall = aggregator_total[t->state] != total[t->state];
+
+		/* Check for stall activity or a previous threshold breach */
+		if (!new_stall && !t->pending_event)
+			continue;
+		/*
+		 * Check for new stall activity, as well as deferred
+		 * events that occurred in the last window after the
+		 * trigger had already fired (we want to ratelimit
+		 * events without dropping any).
+		 */
+		if (new_stall) {
+			/*
+			 * Multiple triggers might be looking at the same state,
+			 * remember to update group->polling_total[] once we've
+			 * been through all of them. Also remember to extend the
+			 * polling time if we see new stall activity.
+			 */
+			*update_total = true;
+
+			/* Calculate growth since last update */
+			growth = window_update(&t->win, now, total[t->state]);
+			if (!t->pending_event) {
+				if (growth < t->threshold)
+					continue;
+
+				t->pending_event = true;
+			}
+		}
+		/* Limit event signaling to once per window */
+		if (now < t->last_event_time + t->win.size)
+			continue;
+
+		/* Generate an event */
+		if (cmpxchg(&t->event, 0, 1) == 0) {
+			if (t->of)
+				kernfs_notify(t->of->kn);
+			else
+				wake_up_interruptible(&t->event_wait);
+		}
+		t->last_event_time = now;
+		/* Reset threshold breach flag once event got generated */
+		t->pending_event = false;
+	}
+
+	return now + group->rtpoll_min_period;
+}
+
+static u64 update_averages(struct psi_group *group, u64 now)
+{
+	unsigned long missed_periods = 0;
+	u64 expires, period;
+	u64 avg_next_update;
+	int s;
+
+	/* avgX= */
+	expires = group->avg_next_update;
+	if (now - expires >= psi_period)
+		missed_periods = div_u64(now - expires, psi_period);
+
+	/*
+	 * The periodic clock tick can get delayed for various
+	 * reasons, especially on loaded systems. To avoid clock
+	 * drift, we schedule the clock in fixed psi_period intervals.
+	 * But the deltas we sample out of the per-cpu buckets above
+	 * are based on the actual time elapsing between clock ticks.
+	 */
+	avg_next_update = expires + ((1 + missed_periods) * psi_period);
+	period = now - (group->avg_last_update + (missed_periods * psi_period));
+	group->avg_last_update = now;
+
+	for (s = 0; s < NR_PSI_STATES - 1; s++) {
+		u32 sample;
+
+		sample = group->total[PSI_AVGS][s] - group->avg_total[s];
+		/*
+		 * Due to the lockless sampling of the time buckets,
+		 * recorded time deltas can slip into the next period,
+		 * which under full pressure can result in samples in
+		 * excess of the period length.
+		 *
+		 * We don't want to report non-sensical pressures in
+		 * excess of 100%, nor do we want to drop such events
+		 * on the floor. Instead we punt any overage into the
+		 * future until pressure subsides. By doing this we
+		 * don't underreport the occurring pressure curve, we
+		 * just report it delayed by one period length.
+		 *
+		 * The error isn't cumulative. As soon as another
+		 * delta slips from a period P to P+1, by definition
+		 * it frees up its time T in P.
+		 */
+		if (sample > period)
+			sample = period;
+		group->avg_total[s] += sample;
+		calc_avgs(group->avg[s], missed_periods, sample, period);
+	}
+
+	return avg_next_update;
+}
+
+static void psi_avgs_work(struct work_struct *work)
+{
+	struct delayed_work *dwork;
+	struct psi_group *group;
+	u32 changed_states;
+	bool update_total;
+	u64 now;
+
+	dwork = to_delayed_work(work);
+	group = container_of(dwork, struct psi_group, avgs_work);
+
+	mutex_lock(&group->avgs_lock);
+
+	now = sched_clock();
+
+	collect_percpu_times(group, PSI_AVGS, &changed_states);
+	/*
+	 * If there is task activity, periodically fold the per-cpu
+	 * times and feed samples into the running averages. If things
+	 * are idle and there is no data to process, stop the clock.
+	 * Once restarted, we'll catch up the running averages in one
+	 * go - see calc_avgs() and missed_periods.
+	 */
+	if (now >= group->avg_next_update) {
+		update_triggers(group, now, &update_total, PSI_AVGS);
+		group->avg_next_update = update_averages(group, now);
+	}
+
+	if (changed_states & PSI_STATE_RESCHEDULE) {
+		schedule_delayed_work(dwork, nsecs_to_jiffies(
+				group->avg_next_update - now) + 1);
+	}
+
+	mutex_unlock(&group->avgs_lock);
+}
+
+static void init_rtpoll_triggers(struct psi_group *group, u64 now)
+{
+	struct psi_trigger *t;
+
+	list_for_each_entry(t, &group->rtpoll_triggers, node)
+		window_reset(&t->win, now,
+				group->total[PSI_POLL][t->state], 0);
+	memcpy(group->rtpoll_total, group->total[PSI_POLL],
+		   sizeof(group->rtpoll_total));
+	group->rtpoll_next_update = now + group->rtpoll_min_period;
+}
+
+/* Schedule polling if it's not already scheduled or forced. */
+static void psi_schedule_rtpoll_work(struct psi_group *group, unsigned long delay,
+				   bool force)
+{
+	struct task_struct *task;
+
+	/*
+	 * atomic_xchg should be called even when !force to provide a
+	 * full memory barrier (see the comment inside psi_rtpoll_work).
+	 */
+	if (atomic_xchg(&group->rtpoll_scheduled, 1) && !force)
+		return;
+
+	rcu_read_lock();
+
+	task = rcu_dereference(group->rtpoll_task);
+	/*
+	 * kworker might be NULL in case psi_trigger_destroy races with
+	 * psi_task_change (hotpath) which can't use locks
+	 */
+	if (likely(task))
+		mod_timer(&group->rtpoll_timer, jiffies + delay);
+	else
+		atomic_set(&group->rtpoll_scheduled, 0);
+
+	rcu_read_unlock();
+}
+
+static void psi_rtpoll_work(struct psi_group *group)
+{
+	bool force_reschedule = false;
+	u32 changed_states;
+	bool update_total;
+	u64 now;
+
+	mutex_lock(&group->rtpoll_trigger_lock);
+
+	now = sched_clock();
+
+	if (now > group->rtpoll_until) {
+		/*
+		 * We are either about to start or might stop polling if no
+		 * state change was recorded. Resetting poll_scheduled leaves
+		 * a small window for psi_group_change to sneak in and schedule
+		 * an immediate poll_work before we get to rescheduling. One
+		 * potential extra wakeup at the end of the polling window
+		 * should be negligible and polling_next_update still keeps
+		 * updates correctly on schedule.
+		 */
+		atomic_set(&group->rtpoll_scheduled, 0);
+		/*
+		 * A task change can race with the poll worker that is supposed to
+		 * report on it. To avoid missing events, ensure ordering between
+		 * poll_scheduled and the task state accesses, such that if the poll
+		 * worker misses the state update, the task change is guaranteed to
+		 * reschedule the poll worker:
+		 *
+		 * poll worker:
+		 *   atomic_set(poll_scheduled, 0)
+		 *   smp_mb()
+		 *   LOAD states
+		 *
+		 * task change:
+		 *   STORE states
+		 *   if atomic_xchg(poll_scheduled, 1) == 0:
+		 *     schedule poll worker
+		 *
+		 * The atomic_xchg() implies a full barrier.
+		 */
+		smp_mb();
+	} else {
+		/* Polling window is not over, keep rescheduling */
+		force_reschedule = true;
+	}
+
+
+	collect_percpu_times(group, PSI_POLL, &changed_states);
+
+	if (changed_states & group->rtpoll_states) {
+		/* Initialize trigger windows when entering polling mode */
+		if (now > group->rtpoll_until)
+			init_rtpoll_triggers(group, now);
+
+		/*
+		 * Keep the monitor active for at least the duration of the
+		 * minimum tracking window as long as monitor states are
+		 * changing.
+		 */
+		group->rtpoll_until = now +
+			group->rtpoll_min_period * UPDATES_PER_WINDOW;
+	}
+
+	if (now > group->rtpoll_until) {
+		group->rtpoll_next_update = ULLONG_MAX;
+		goto out;
+	}
+
+	if (now >= group->rtpoll_next_update) {
+		group->rtpoll_next_update = update_triggers(group, now, &update_total, PSI_POLL);
+		if (update_total)
+			memcpy(group->rtpoll_total, group->total[PSI_POLL],
+				   sizeof(group->rtpoll_total));
+	}
+
+	psi_schedule_rtpoll_work(group,
+		nsecs_to_jiffies(group->rtpoll_next_update - now) + 1,
+		force_reschedule);
+
+out:
+	mutex_unlock(&group->rtpoll_trigger_lock);
+}
+
+static int psi_rtpoll_worker(void *data)
+{
+	struct psi_group *group = (struct psi_group *)data;
+
+	sched_set_fifo_low(current);
+
+	while (true) {
+		wait_event_interruptible(group->rtpoll_wait,
+				atomic_cmpxchg(&group->rtpoll_wakeup, 1, 0) ||
+				kthread_should_stop());
+		if (kthread_should_stop())
+			break;
+
+		psi_rtpoll_work(group);
+	}
+	return 0;
+}
+
+static void poll_timer_fn(struct timer_list *t)
+{
+	struct psi_group *group = from_timer(group, t, rtpoll_timer);
+
+	atomic_set(&group->rtpoll_wakeup, 1);
+	wake_up_interruptible(&group->rtpoll_wait);
+}
+
+static void record_times(struct psi_group_cpu *groupc, u64 now)
+{
+	u32 delta;
+
+	delta = now - groupc->state_start;
+	groupc->state_start = now;
+
+	if (groupc->state_mask & (1 << PSI_IO_SOME)) {
+		groupc->times[PSI_IO_SOME] += delta;
+		if (groupc->state_mask & (1 << PSI_IO_FULL))
+			groupc->times[PSI_IO_FULL] += delta;
+	}
+
+	if (groupc->state_mask & (1 << PSI_MEM_SOME)) {
+		groupc->times[PSI_MEM_SOME] += delta;
+		if (groupc->state_mask & (1 << PSI_MEM_FULL))
+			groupc->times[PSI_MEM_FULL] += delta;
+	}
+
+	if (groupc->state_mask & (1 << PSI_CPU_SOME)) {
+		groupc->times[PSI_CPU_SOME] += delta;
+		if (groupc->state_mask & (1 << PSI_CPU_FULL))
+			groupc->times[PSI_CPU_FULL] += delta;
+	}
+
+	if (groupc->state_mask & (1 << PSI_NONIDLE))
+		groupc->times[PSI_NONIDLE] += delta;
+}
+
+static void psi_group_change(struct psi_group *group, int cpu,
+			     unsigned int clear, unsigned int set, u64 now,
+			     bool wake_clock)
+{
+	struct psi_group_cpu *groupc;
+	unsigned int t, m;
+	enum psi_states s;
+	u32 state_mask;
+
+	groupc = per_cpu_ptr(group->pcpu, cpu);
+
+	/*
+	 * First we update the task counts according to the state
+	 * change requested through the @clear and @set bits.
+	 *
+	 * Then if the cgroup PSI stats accounting enabled, we
+	 * assess the aggregate resource states this CPU's tasks
+	 * have been in since the last change, and account any
+	 * SOME and FULL time these may have resulted in.
+	 */
+	write_seqcount_begin(&groupc->seq);
+
+	/*
+	 * Start with TSK_ONCPU, which doesn't have a corresponding
+	 * task count - it's just a boolean flag directly encoded in
+	 * the state mask. Clear, set, or carry the current state if
+	 * no changes are requested.
+	 */
+	if (unlikely(clear & TSK_ONCPU)) {
+		state_mask = 0;
+		clear &= ~TSK_ONCPU;
+	} else if (unlikely(set & TSK_ONCPU)) {
+		state_mask = PSI_ONCPU;
+		set &= ~TSK_ONCPU;
+	} else {
+		state_mask = groupc->state_mask & PSI_ONCPU;
+	}
+
+	/*
+	 * The rest of the state mask is calculated based on the task
+	 * counts. Update those first, then construct the mask.
+	 */
+	for (t = 0, m = clear; m; m &= ~(1 << t), t++) {
+		if (!(m & (1 << t)))
+			continue;
+		if (groupc->tasks[t]) {
+			groupc->tasks[t]--;
+		} else if (!psi_bug) {
+			printk_deferred(KERN_ERR "psi: task underflow! cpu=%d t=%d tasks=[%u %u %u %u] clear=%x set=%x\n",
+					cpu, t, groupc->tasks[0],
+					groupc->tasks[1], groupc->tasks[2],
+					groupc->tasks[3], clear, set);
+			psi_bug = 1;
+		}
+	}
+
+	for (t = 0; set; set &= ~(1 << t), t++)
+		if (set & (1 << t))
+			groupc->tasks[t]++;
+
+	if (!group->enabled) {
+		/*
+		 * On the first group change after disabling PSI, conclude
+		 * the current state and flush its time. This is unlikely
+		 * to matter to the user, but aggregation (get_recent_times)
+		 * may have already incorporated the live state into times_prev;
+		 * avoid a delta sample underflow when PSI is later re-enabled.
+		 */
+		if (unlikely(groupc->state_mask & (1 << PSI_NONIDLE)))
+			record_times(groupc, now);
+
+		groupc->state_mask = state_mask;
+
+		write_seqcount_end(&groupc->seq);
+		return;
+	}
+
+	for (s = 0; s < NR_PSI_STATES; s++) {
+		if (test_state(groupc->tasks, s, state_mask & PSI_ONCPU))
+			state_mask |= (1 << s);
+	}
+
+	/*
+	 * Since we care about lost potential, a memstall is FULL
+	 * when there are no other working tasks, but also when
+	 * the CPU is actively reclaiming and nothing productive
+	 * could run even if it were runnable. So when the current
+	 * task in a cgroup is in_memstall, the corresponding groupc
+	 * on that cpu is in PSI_MEM_FULL state.
+	 */
+	if (unlikely((state_mask & PSI_ONCPU) && cpu_curr(cpu)->in_memstall))
+		state_mask |= (1 << PSI_MEM_FULL);
+
+	record_times(groupc, now);
+
+	groupc->state_mask = state_mask;
+
+	write_seqcount_end(&groupc->seq);
+
+	if (state_mask & group->rtpoll_states)
+		psi_schedule_rtpoll_work(group, 1, false);
+
+	if (wake_clock && !delayed_work_pending(&group->avgs_work))
+		schedule_delayed_work(&group->avgs_work, PSI_FREQ);
+}
+
+static inline struct psi_group *task_psi_group(struct task_struct *task)
+{
+#ifdef CONFIG_CGROUPS
+	if (static_branch_likely(&psi_cgroups_enabled))
+		return cgroup_psi(task_dfl_cgroup(task));
+#endif
+	return &psi_system;
+}
+
+static void psi_flags_change(struct task_struct *task, int clear, int set)
+{
+	if (((task->psi_flags & set) ||
+	     (task->psi_flags & clear) != clear) &&
+	    !psi_bug) {
+		printk_deferred(KERN_ERR "psi: inconsistent task state! task=%d:%s cpu=%d psi_flags=%x clear=%x set=%x\n",
+				task->pid, task->comm, task_cpu(task),
+				task->psi_flags, clear, set);
+		psi_bug = 1;
+	}
+
+	task->psi_flags &= ~clear;
+	task->psi_flags |= set;
+}
+
+void psi_task_change(struct task_struct *task, int clear, int set)
+{
+	int cpu = task_cpu(task);
+	struct psi_group *group;
+	u64 now;
+
+	if (!task->pid)
+		return;
+
+	psi_flags_change(task, clear, set);
+
+	now = cpu_clock(cpu);
+
+	group = task_psi_group(task);
+	do {
+		psi_group_change(group, cpu, clear, set, now, true);
+	} while ((group = group->parent));
+}
+
+void psi_task_switch(struct task_struct *prev, struct task_struct *next,
+		     bool sleep)
+{
+	struct psi_group *group, *common = NULL;
+	int cpu = task_cpu(prev);
+	u64 now = cpu_clock(cpu);
+
+	if (next->pid) {
+		psi_flags_change(next, 0, TSK_ONCPU);
+		/*
+		 * Set TSK_ONCPU on @next's cgroups. If @next shares any
+		 * ancestors with @prev, those will already have @prev's
+		 * TSK_ONCPU bit set, and we can stop the iteration there.
+		 */
+		group = task_psi_group(next);
+		do {
+			if (per_cpu_ptr(group->pcpu, cpu)->state_mask &
+			    PSI_ONCPU) {
+				common = group;
+				break;
+			}
+
+			psi_group_change(group, cpu, 0, TSK_ONCPU, now, true);
+		} while ((group = group->parent));
+	}
+
+	if (prev->pid) {
+		int clear = TSK_ONCPU, set = 0;
+		bool wake_clock = true;
+
+		/*
+		 * When we're going to sleep, psi_dequeue() lets us
+		 * handle TSK_RUNNING, TSK_MEMSTALL_RUNNING and
+		 * TSK_IOWAIT here, where we can combine it with
+		 * TSK_ONCPU and save walking common ancestors twice.
+		 */
+		if (sleep) {
+			clear |= TSK_RUNNING;
+			if (prev->in_memstall)
+				clear |= TSK_MEMSTALL_RUNNING;
+			if (prev->in_iowait)
+				set |= TSK_IOWAIT;
+
+			/*
+			 * Periodic aggregation shuts off if there is a period of no
+			 * task changes, so we wake it back up if necessary. However,
+			 * don't do this if the task change is the aggregation worker
+			 * itself going to sleep, or we'll ping-pong forever.
+			 */
+			if (unlikely((prev->flags & PF_WQ_WORKER) &&
+				     wq_worker_last_func(prev) == psi_avgs_work))
+				wake_clock = false;
+		}
+
+		psi_flags_change(prev, clear, set);
+
+		group = task_psi_group(prev);
+		do {
+			if (group == common)
+				break;
+			psi_group_change(group, cpu, clear, set, now, wake_clock);
+		} while ((group = group->parent));
+
+		/*
+		 * TSK_ONCPU is handled up to the common ancestor. If there are
+		 * any other differences between the two tasks (e.g. prev goes
+		 * to sleep, or only one task is memstall), finish propagating
+		 * those differences all the way up to the root.
+		 */
+		if ((prev->psi_flags ^ next->psi_flags) & ~TSK_ONCPU) {
+			clear &= ~TSK_ONCPU;
+			for (; group; group = group->parent)
+				psi_group_change(group, cpu, clear, set, now, wake_clock);
+		}
+	}
+}
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+void psi_account_irqtime(struct task_struct *task, u32 delta)
+{
+	int cpu = task_cpu(task);
+	struct psi_group *group;
+	struct psi_group_cpu *groupc;
+	u64 now;
+
+	if (!task->pid)
+		return;
+
+	now = cpu_clock(cpu);
+
+	group = task_psi_group(task);
+	do {
+		if (!group->enabled)
+			continue;
+
+		groupc = per_cpu_ptr(group->pcpu, cpu);
+
+		write_seqcount_begin(&groupc->seq);
+
+		record_times(groupc, now);
+		groupc->times[PSI_IRQ_FULL] += delta;
+
+		write_seqcount_end(&groupc->seq);
+
+		if (group->rtpoll_states & (1 << PSI_IRQ_FULL))
+			psi_schedule_rtpoll_work(group, 1, false);
+	} while ((group = group->parent));
+}
+#endif
+
+/**
+ * psi_memstall_enter - mark the beginning of a memory stall section
+ * @flags: flags to handle nested sections
+ *
+ * Marks the calling task as being stalled due to a lack of memory,
+ * such as waiting for a refault or performing reclaim.
+ */
+void psi_memstall_enter(unsigned long *flags)
+{
+	struct rq_flags rf;
+	struct rq *rq;
+
+	if (static_branch_likely(&psi_disabled))
+		return;
+
+	*flags = current->in_memstall;
+	if (*flags)
+		return;
+	/*
+	 * in_memstall setting & accounting needs to be atomic wrt
+	 * changes to the task's scheduling state, otherwise we can
+	 * race with CPU migration.
+	 */
+	rq = this_rq_lock_irq(&rf);
+
+	current->in_memstall = 1;
+	psi_task_change(current, 0, TSK_MEMSTALL | TSK_MEMSTALL_RUNNING);
+
+	rq_unlock_irq(rq, &rf);
+}
+EXPORT_SYMBOL_GPL(psi_memstall_enter);
+
+/**
+ * psi_memstall_leave - mark the end of an memory stall section
+ * @flags: flags to handle nested memdelay sections
+ *
+ * Marks the calling task as no longer stalled due to lack of memory.
+ */
+void psi_memstall_leave(unsigned long *flags)
+{
+	struct rq_flags rf;
+	struct rq *rq;
+
+	if (static_branch_likely(&psi_disabled))
+		return;
+
+	if (*flags)
+		return;
+	/*
+	 * in_memstall clearing & accounting needs to be atomic wrt
+	 * changes to the task's scheduling state, otherwise we could
+	 * race with CPU migration.
+	 */
+	rq = this_rq_lock_irq(&rf);
+
+	current->in_memstall = 0;
+	psi_task_change(current, TSK_MEMSTALL | TSK_MEMSTALL_RUNNING, 0);
+
+	rq_unlock_irq(rq, &rf);
+}
+EXPORT_SYMBOL_GPL(psi_memstall_leave);
+
+#ifdef CONFIG_CGROUPS
+int psi_cgroup_alloc(struct cgroup *cgroup)
+{
+	if (!static_branch_likely(&psi_cgroups_enabled))
+		return 0;
+
+	cgroup->psi = kzalloc(sizeof(struct psi_group), GFP_KERNEL);
+	if (!cgroup->psi)
+		return -ENOMEM;
+
+	cgroup->psi->pcpu = alloc_percpu(struct psi_group_cpu);
+	if (!cgroup->psi->pcpu) {
+		kfree(cgroup->psi);
+		return -ENOMEM;
+	}
+	group_init(cgroup->psi);
+	cgroup->psi->parent = cgroup_psi(cgroup_parent(cgroup));
+	return 0;
+}
+
+void psi_cgroup_free(struct cgroup *cgroup)
+{
+	if (!static_branch_likely(&psi_cgroups_enabled))
+		return;
+
+	cancel_delayed_work_sync(&cgroup->psi->avgs_work);
+	free_percpu(cgroup->psi->pcpu);
+	/* All triggers must be removed by now */
+	WARN_ONCE(cgroup->psi->rtpoll_states, "psi: trigger leak\n");
+	kfree(cgroup->psi);
+}
+
+/**
+ * cgroup_move_task - move task to a different cgroup
+ * @task: the task
+ * @to: the target css_set
+ *
+ * Move task to a new cgroup and safely migrate its associated stall
+ * state between the different groups.
+ *
+ * This function acquires the task's rq lock to lock out concurrent
+ * changes to the task's scheduling state and - in case the task is
+ * running - concurrent changes to its stall state.
+ */
+void cgroup_move_task(struct task_struct *task, struct css_set *to)
+{
+	unsigned int task_flags;
+	struct rq_flags rf;
+	struct rq *rq;
+
+	if (!static_branch_likely(&psi_cgroups_enabled)) {
+		/*
+		 * Lame to do this here, but the scheduler cannot be locked
+		 * from the outside, so we move cgroups from inside sched/.
+		 */
+		rcu_assign_pointer(task->cgroups, to);
+		return;
+	}
+
+	rq = task_rq_lock(task, &rf);
+
+	/*
+	 * We may race with schedule() dropping the rq lock between
+	 * deactivating prev and switching to next. Because the psi
+	 * updates from the deactivation are deferred to the switch
+	 * callback to save cgroup tree updates, the task's scheduling
+	 * state here is not coherent with its psi state:
+	 *
+	 * schedule()                   cgroup_move_task()
+	 *   rq_lock()
+	 *   deactivate_task()
+	 *     p->on_rq = 0
+	 *     psi_dequeue() // defers TSK_RUNNING & TSK_IOWAIT updates
+	 *   pick_next_task()
+	 *     rq_unlock()
+	 *                                rq_lock()
+	 *                                psi_task_change() // old cgroup
+	 *                                task->cgroups = to
+	 *                                psi_task_change() // new cgroup
+	 *                                rq_unlock()
+	 *     rq_lock()
+	 *   psi_sched_switch() // does deferred updates in new cgroup
+	 *
+	 * Don't rely on the scheduling state. Use psi_flags instead.
+	 */
+	task_flags = task->psi_flags;
+
+	if (task_flags)
+		psi_task_change(task, task_flags, 0);
+
+	/* See comment above */
+	rcu_assign_pointer(task->cgroups, to);
+
+	if (task_flags)
+		psi_task_change(task, 0, task_flags);
+
+	task_rq_unlock(rq, task, &rf);
+}
+
+void psi_cgroup_restart(struct psi_group *group)
+{
+	int cpu;
+
+	/*
+	 * After we disable psi_group->enabled, we don't actually
+	 * stop percpu tasks accounting in each psi_group_cpu,
+	 * instead only stop test_state() loop, record_times()
+	 * and averaging worker, see psi_group_change() for details.
+	 *
+	 * When disable cgroup PSI, this function has nothing to sync
+	 * since cgroup pressure files are hidden and percpu psi_group_cpu
+	 * would see !psi_group->enabled and only do task accounting.
+	 *
+	 * When re-enable cgroup PSI, this function use psi_group_change()
+	 * to get correct state mask from test_state() loop on tasks[],
+	 * and restart groupc->state_start from now, use .clear = .set = 0
+	 * here since no task status really changed.
+	 */
+	if (!group->enabled)
+		return;
+
+	for_each_possible_cpu(cpu) {
+		struct rq *rq = cpu_rq(cpu);
+		struct rq_flags rf;
+		u64 now;
+
+		rq_lock_irq(rq, &rf);
+		now = cpu_clock(cpu);
+		psi_group_change(group, cpu, 0, 0, now, true);
+		rq_unlock_irq(rq, &rf);
+	}
+}
+#endif /* CONFIG_CGROUPS */
+
+int psi_show(struct seq_file *m, struct psi_group *group, enum psi_res res)
+{
+	bool only_full = false;
+	int full;
+	u64 now;
+
+	if (static_branch_likely(&psi_disabled))
+		return -EOPNOTSUPP;
+
+	/* Update averages before reporting them */
+	mutex_lock(&group->avgs_lock);
+	now = sched_clock();
+	collect_percpu_times(group, PSI_AVGS, NULL);
+	if (now >= group->avg_next_update)
+		group->avg_next_update = update_averages(group, now);
+	mutex_unlock(&group->avgs_lock);
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+	only_full = res == PSI_IRQ;
+#endif
+
+	for (full = 0; full < 2 - only_full; full++) {
+		unsigned long avg[3] = { 0, };
+		u64 total = 0;
+		int w;
+
+		/* CPU FULL is undefined at the system level */
+		if (!(group == &psi_system && res == PSI_CPU && full)) {
+			for (w = 0; w < 3; w++)
+				avg[w] = group->avg[res * 2 + full][w];
+			total = div_u64(group->total[PSI_AVGS][res * 2 + full],
+					NSEC_PER_USEC);
+		}
+
+		seq_printf(m, "%s avg10=%lu.%02lu avg60=%lu.%02lu avg300=%lu.%02lu total=%llu\n",
+			   full || only_full ? "full" : "some",
+			   LOAD_INT(avg[0]), LOAD_FRAC(avg[0]),
+			   LOAD_INT(avg[1]), LOAD_FRAC(avg[1]),
+			   LOAD_INT(avg[2]), LOAD_FRAC(avg[2]),
+			   total);
+	}
+
+	return 0;
+}
+
+struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf,
+				       enum psi_res res, struct file *file,
+				       struct kernfs_open_file *of)
+{
+	struct psi_trigger *t;
+	enum psi_states state;
+	u32 threshold_us;
+	bool privileged;
+	u32 window_us;
+
+	if (static_branch_likely(&psi_disabled))
+		return ERR_PTR(-EOPNOTSUPP);
+
+	/*
+	 * Checking the privilege here on file->f_cred implies that a privileged user
+	 * could open the file and delegate the write to an unprivileged one.
+	 */
+	privileged = cap_raised(file->f_cred->cap_effective, CAP_SYS_RESOURCE);
+
+	if (sscanf(buf, "some %u %u", &threshold_us, &window_us) == 2)
+		state = PSI_IO_SOME + res * 2;
+	else if (sscanf(buf, "full %u %u", &threshold_us, &window_us) == 2)
+		state = PSI_IO_FULL + res * 2;
+	else
+		return ERR_PTR(-EINVAL);
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+	if (res == PSI_IRQ && --state != PSI_IRQ_FULL)
+		return ERR_PTR(-EINVAL);
+#endif
+
+	if (state >= PSI_NONIDLE)
+		return ERR_PTR(-EINVAL);
+
+	if (window_us == 0 || window_us > WINDOW_MAX_US)
+		return ERR_PTR(-EINVAL);
+
+	/*
+	 * Unprivileged users can only use 2s windows so that averages aggregation
+	 * work is used, and no RT threads need to be spawned.
+	 */
+	if (!privileged && window_us % 2000000)
+		return ERR_PTR(-EINVAL);
+
+	/* Check threshold */
+	if (threshold_us == 0 || threshold_us > window_us)
+		return ERR_PTR(-EINVAL);
+
+	t = kmalloc(sizeof(*t), GFP_KERNEL);
+	if (!t)
+		return ERR_PTR(-ENOMEM);
+
+	t->group = group;
+	t->state = state;
+	t->threshold = threshold_us * NSEC_PER_USEC;
+	t->win.size = window_us * NSEC_PER_USEC;
+	window_reset(&t->win, sched_clock(),
+			group->total[PSI_POLL][t->state], 0);
+
+	t->event = 0;
+	t->last_event_time = 0;
+	t->of = of;
+	if (!of)
+		init_waitqueue_head(&t->event_wait);
+	t->pending_event = false;
+	t->aggregator = privileged ? PSI_POLL : PSI_AVGS;
+
+	if (privileged) {
+		mutex_lock(&group->rtpoll_trigger_lock);
+
+		if (!rcu_access_pointer(group->rtpoll_task)) {
+			struct task_struct *task;
+
+			task = kthread_create(psi_rtpoll_worker, group, "psimon");
+			if (IS_ERR(task)) {
+				kfree(t);
+				mutex_unlock(&group->rtpoll_trigger_lock);
+				return ERR_CAST(task);
+			}
+			atomic_set(&group->rtpoll_wakeup, 0);
+			wake_up_process(task);
+			rcu_assign_pointer(group->rtpoll_task, task);
+		}
+
+		list_add(&t->node, &group->rtpoll_triggers);
+		group->rtpoll_min_period = min(group->rtpoll_min_period,
+			div_u64(t->win.size, UPDATES_PER_WINDOW));
+		group->rtpoll_nr_triggers[t->state]++;
+		group->rtpoll_states |= (1 << t->state);
+
+		mutex_unlock(&group->rtpoll_trigger_lock);
+	} else {
+		mutex_lock(&group->avgs_lock);
+
+		list_add(&t->node, &group->avg_triggers);
+		group->avg_nr_triggers[t->state]++;
+
+		mutex_unlock(&group->avgs_lock);
+	}
+	return t;
+}
+
+void psi_trigger_destroy(struct psi_trigger *t)
+{
+	struct psi_group *group;
+	struct task_struct *task_to_destroy = NULL;
+
+	/*
+	 * We do not check psi_disabled since it might have been disabled after
+	 * the trigger got created.
+	 */
+	if (!t)
+		return;
+
+	group = t->group;
+	/*
+	 * Wakeup waiters to stop polling and clear the queue to prevent it from
+	 * being accessed later. Can happen if cgroup is deleted from under a
+	 * polling process.
+	 */
+	if (t->of)
+		kernfs_notify(t->of->kn);
+	else
+		wake_up_interruptible(&t->event_wait);
+
+	if (t->aggregator == PSI_AVGS) {
+		mutex_lock(&group->avgs_lock);
+		if (!list_empty(&t->node)) {
+			list_del(&t->node);
+			group->avg_nr_triggers[t->state]--;
+		}
+		mutex_unlock(&group->avgs_lock);
+	} else {
+		mutex_lock(&group->rtpoll_trigger_lock);
+		if (!list_empty(&t->node)) {
+			struct psi_trigger *tmp;
+			u64 period = ULLONG_MAX;
+
+			list_del(&t->node);
+			group->rtpoll_nr_triggers[t->state]--;
+			if (!group->rtpoll_nr_triggers[t->state])
+				group->rtpoll_states &= ~(1 << t->state);
+			/*
+			 * Reset min update period for the remaining triggers
+			 * iff the destroying trigger had the min window size.
+			 */
+			if (group->rtpoll_min_period == div_u64(t->win.size, UPDATES_PER_WINDOW)) {
+				list_for_each_entry(tmp, &group->rtpoll_triggers, node)
+					period = min(period, div_u64(tmp->win.size,
+							UPDATES_PER_WINDOW));
+				group->rtpoll_min_period = period;
+			}
+			/* Destroy rtpoll_task when the last trigger is destroyed */
+			if (group->rtpoll_states == 0) {
+				group->rtpoll_until = 0;
+				task_to_destroy = rcu_dereference_protected(
+						group->rtpoll_task,
+						lockdep_is_held(&group->rtpoll_trigger_lock));
+				rcu_assign_pointer(group->rtpoll_task, NULL);
+				del_timer(&group->rtpoll_timer);
+			}
+		}
+		mutex_unlock(&group->rtpoll_trigger_lock);
+	}
+
+	/*
+	 * Wait for psi_schedule_rtpoll_work RCU to complete its read-side
+	 * critical section before destroying the trigger and optionally the
+	 * rtpoll_task.
+	 */
+	synchronize_rcu();
+	/*
+	 * Stop kthread 'psimon' after releasing rtpoll_trigger_lock to prevent
+	 * a deadlock while waiting for psi_rtpoll_work to acquire
+	 * rtpoll_trigger_lock
+	 */
+	if (task_to_destroy) {
+		/*
+		 * After the RCU grace period has expired, the worker
+		 * can no longer be found through group->rtpoll_task.
+		 */
+		kthread_stop(task_to_destroy);
+		atomic_set(&group->rtpoll_scheduled, 0);
+	}
+	kfree(t);
+}
+
+__poll_t psi_trigger_poll(void **trigger_ptr,
+				struct file *file, poll_table *wait)
+{
+	__poll_t ret = DEFAULT_POLLMASK;
+	struct psi_trigger *t;
+
+	if (static_branch_likely(&psi_disabled))
+		return DEFAULT_POLLMASK | EPOLLERR | EPOLLPRI;
+
+	t = smp_load_acquire(trigger_ptr);
+	if (!t)
+		return DEFAULT_POLLMASK | EPOLLERR | EPOLLPRI;
+
+	if (t->of)
+		kernfs_generic_poll(t->of, wait);
+	else
+		poll_wait(file, &t->event_wait, wait);
+
+	if (cmpxchg(&t->event, 1, 0) == 1)
+		ret |= EPOLLPRI;
+
+	return ret;
+}
+
+#ifdef CONFIG_PROC_FS
+static int psi_io_show(struct seq_file *m, void *v)
+{
+	return psi_show(m, &psi_system, PSI_IO);
+}
+
+static int psi_memory_show(struct seq_file *m, void *v)
+{
+	return psi_show(m, &psi_system, PSI_MEM);
+}
+
+static int psi_cpu_show(struct seq_file *m, void *v)
+{
+	return psi_show(m, &psi_system, PSI_CPU);
+}
+
+static int psi_io_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, psi_io_show, NULL);
+}
+
+static int psi_memory_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, psi_memory_show, NULL);
+}
+
+static int psi_cpu_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, psi_cpu_show, NULL);
+}
+
+static ssize_t psi_write(struct file *file, const char __user *user_buf,
+			 size_t nbytes, enum psi_res res)
+{
+	char buf[32];
+	size_t buf_size;
+	struct seq_file *seq;
+	struct psi_trigger *new;
+
+	if (static_branch_likely(&psi_disabled))
+		return -EOPNOTSUPP;
+
+	if (!nbytes)
+		return -EINVAL;
+
+	buf_size = min(nbytes, sizeof(buf));
+	if (copy_from_user(buf, user_buf, buf_size))
+		return -EFAULT;
+
+	buf[buf_size - 1] = '\0';
+
+	seq = file->private_data;
+
+	/* Take seq->lock to protect seq->private from concurrent writes */
+	mutex_lock(&seq->lock);
+
+	/* Allow only one trigger per file descriptor */
+	if (seq->private) {
+		mutex_unlock(&seq->lock);
+		return -EBUSY;
+	}
+
+	new = psi_trigger_create(&psi_system, buf, res, file, NULL);
+	if (IS_ERR(new)) {
+		mutex_unlock(&seq->lock);
+		return PTR_ERR(new);
+	}
+
+	smp_store_release(&seq->private, new);
+	mutex_unlock(&seq->lock);
+
+	return nbytes;
+}
+
+static ssize_t psi_io_write(struct file *file, const char __user *user_buf,
+			    size_t nbytes, loff_t *ppos)
+{
+	return psi_write(file, user_buf, nbytes, PSI_IO);
+}
+
+static ssize_t psi_memory_write(struct file *file, const char __user *user_buf,
+				size_t nbytes, loff_t *ppos)
+{
+	return psi_write(file, user_buf, nbytes, PSI_MEM);
+}
+
+static ssize_t psi_cpu_write(struct file *file, const char __user *user_buf,
+			     size_t nbytes, loff_t *ppos)
+{
+	return psi_write(file, user_buf, nbytes, PSI_CPU);
+}
+
+static __poll_t psi_fop_poll(struct file *file, poll_table *wait)
+{
+	struct seq_file *seq = file->private_data;
+
+	return psi_trigger_poll(&seq->private, file, wait);
+}
+
+static int psi_fop_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *seq = file->private_data;
+
+	psi_trigger_destroy(seq->private);
+	return single_release(inode, file);
+}
+
+static const struct proc_ops psi_io_proc_ops = {
+	.proc_open	= psi_io_open,
+	.proc_read	= seq_read,
+	.proc_lseek	= seq_lseek,
+	.proc_write	= psi_io_write,
+	.proc_poll	= psi_fop_poll,
+	.proc_release	= psi_fop_release,
+};
+
+static const struct proc_ops psi_memory_proc_ops = {
+	.proc_open	= psi_memory_open,
+	.proc_read	= seq_read,
+	.proc_lseek	= seq_lseek,
+	.proc_write	= psi_memory_write,
+	.proc_poll	= psi_fop_poll,
+	.proc_release	= psi_fop_release,
+};
+
+static const struct proc_ops psi_cpu_proc_ops = {
+	.proc_open	= psi_cpu_open,
+	.proc_read	= seq_read,
+	.proc_lseek	= seq_lseek,
+	.proc_write	= psi_cpu_write,
+	.proc_poll	= psi_fop_poll,
+	.proc_release	= psi_fop_release,
+};
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+static int psi_irq_show(struct seq_file *m, void *v)
+{
+	return psi_show(m, &psi_system, PSI_IRQ);
+}
+
+static int psi_irq_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, psi_irq_show, NULL);
+}
+
+static ssize_t psi_irq_write(struct file *file, const char __user *user_buf,
+			     size_t nbytes, loff_t *ppos)
+{
+	return psi_write(file, user_buf, nbytes, PSI_IRQ);
+}
+
+static const struct proc_ops psi_irq_proc_ops = {
+	.proc_open	= psi_irq_open,
+	.proc_read	= seq_read,
+	.proc_lseek	= seq_lseek,
+	.proc_write	= psi_irq_write,
+	.proc_poll	= psi_fop_poll,
+	.proc_release	= psi_fop_release,
+};
+#endif
+
+static int __init psi_proc_init(void)
+{
+	if (psi_enable) {
+		proc_mkdir("pressure", NULL);
+		proc_create("pressure/io", 0666, NULL, &psi_io_proc_ops);
+		proc_create("pressure/memory", 0666, NULL, &psi_memory_proc_ops);
+		proc_create("pressure/cpu", 0666, NULL, &psi_cpu_proc_ops);
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+		proc_create("pressure/irq", 0666, NULL, &psi_irq_proc_ops);
+#endif
+	}
+	return 0;
+}
+module_init(psi_proc_init);
+
+#endif /* CONFIG_PROC_FS */
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
new file mode 100644
index 0000000000..904dd85345
--- /dev/null
+++ b/kernel/sched/rt.c
@@ -0,0 +1,3090 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Real-Time Scheduling Class (mapped to the SCHED_FIFO and SCHED_RR
+ * policies)
+ */
+
+int sched_rr_timeslice = RR_TIMESLICE;
+/* More than 4 hours if BW_SHIFT equals 20. */
+static const u64 max_rt_runtime = MAX_BW;
+
+static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
+
+struct rt_bandwidth def_rt_bandwidth;
+
+/*
+ * period over which we measure -rt task CPU usage in us.
+ * default: 1s
+ */
+unsigned int sysctl_sched_rt_period = 1000000;
+
+/*
+ * part of the period that we allow rt tasks to run in us.
+ * default: 0.95s
+ */
+int sysctl_sched_rt_runtime = 950000;
+
+#ifdef CONFIG_SYSCTL
+static int sysctl_sched_rr_timeslice = (MSEC_PER_SEC * RR_TIMESLICE) / HZ;
+static int sched_rt_handler(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos);
+static int sched_rr_handler(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos);
+static struct ctl_table sched_rt_sysctls[] = {
+	{
+		.procname       = "sched_rt_period_us",
+		.data           = &sysctl_sched_rt_period,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = sched_rt_handler,
+	},
+	{
+		.procname       = "sched_rt_runtime_us",
+		.data           = &sysctl_sched_rt_runtime,
+		.maxlen         = sizeof(int),
+		.mode           = 0644,
+		.proc_handler   = sched_rt_handler,
+	},
+	{
+		.procname       = "sched_rr_timeslice_ms",
+		.data           = &sysctl_sched_rr_timeslice,
+		.maxlen         = sizeof(int),
+		.mode           = 0644,
+		.proc_handler   = sched_rr_handler,
+	},
+	{}
+};
+
+static int __init sched_rt_sysctl_init(void)
+{
+	register_sysctl_init("kernel", sched_rt_sysctls);
+	return 0;
+}
+late_initcall(sched_rt_sysctl_init);
+#endif
+
+static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
+{
+	struct rt_bandwidth *rt_b =
+		container_of(timer, struct rt_bandwidth, rt_period_timer);
+	int idle = 0;
+	int overrun;
+
+	raw_spin_lock(&rt_b->rt_runtime_lock);
+	for (;;) {
+		overrun = hrtimer_forward_now(timer, rt_b->rt_period);
+		if (!overrun)
+			break;
+
+		raw_spin_unlock(&rt_b->rt_runtime_lock);
+		idle = do_sched_rt_period_timer(rt_b, overrun);
+		raw_spin_lock(&rt_b->rt_runtime_lock);
+	}
+	if (idle)
+		rt_b->rt_period_active = 0;
+	raw_spin_unlock(&rt_b->rt_runtime_lock);
+
+	return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
+}
+
+void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
+{
+	rt_b->rt_period = ns_to_ktime(period);
+	rt_b->rt_runtime = runtime;
+
+	raw_spin_lock_init(&rt_b->rt_runtime_lock);
+
+	hrtimer_init(&rt_b->rt_period_timer, CLOCK_MONOTONIC,
+		     HRTIMER_MODE_REL_HARD);
+	rt_b->rt_period_timer.function = sched_rt_period_timer;
+}
+
+static inline void do_start_rt_bandwidth(struct rt_bandwidth *rt_b)
+{
+	raw_spin_lock(&rt_b->rt_runtime_lock);
+	if (!rt_b->rt_period_active) {
+		rt_b->rt_period_active = 1;
+		/*
+		 * SCHED_DEADLINE updates the bandwidth, as a run away
+		 * RT task with a DL task could hog a CPU. But DL does
+		 * not reset the period. If a deadline task was running
+		 * without an RT task running, it can cause RT tasks to
+		 * throttle when they start up. Kick the timer right away
+		 * to update the period.
+		 */
+		hrtimer_forward_now(&rt_b->rt_period_timer, ns_to_ktime(0));
+		hrtimer_start_expires(&rt_b->rt_period_timer,
+				      HRTIMER_MODE_ABS_PINNED_HARD);
+	}
+	raw_spin_unlock(&rt_b->rt_runtime_lock);
+}
+
+static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
+{
+	if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
+		return;
+
+	do_start_rt_bandwidth(rt_b);
+}
+
+void init_rt_rq(struct rt_rq *rt_rq)
+{
+	struct rt_prio_array *array;
+	int i;
+
+	array = &rt_rq->active;
+	for (i = 0; i < MAX_RT_PRIO; i++) {
+		INIT_LIST_HEAD(array->queue + i);
+		__clear_bit(i, array->bitmap);
+	}
+	/* delimiter for bitsearch: */
+	__set_bit(MAX_RT_PRIO, array->bitmap);
+
+#if defined CONFIG_SMP
+	rt_rq->highest_prio.curr = MAX_RT_PRIO-1;
+	rt_rq->highest_prio.next = MAX_RT_PRIO-1;
+	rt_rq->rt_nr_migratory = 0;
+	rt_rq->overloaded = 0;
+	plist_head_init(&rt_rq->pushable_tasks);
+#endif /* CONFIG_SMP */
+	/* We start is dequeued state, because no RT tasks are queued */
+	rt_rq->rt_queued = 0;
+
+	rt_rq->rt_time = 0;
+	rt_rq->rt_throttled = 0;
+	rt_rq->rt_runtime = 0;
+	raw_spin_lock_init(&rt_rq->rt_runtime_lock);
+}
+
+#ifdef CONFIG_RT_GROUP_SCHED
+static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
+{
+	hrtimer_cancel(&rt_b->rt_period_timer);
+}
+
+#define rt_entity_is_task(rt_se) (!(rt_se)->my_q)
+
+static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
+{
+#ifdef CONFIG_SCHED_DEBUG
+	WARN_ON_ONCE(!rt_entity_is_task(rt_se));
+#endif
+	return container_of(rt_se, struct task_struct, rt);
+}
+
+static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
+{
+	return rt_rq->rq;
+}
+
+static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
+{
+	return rt_se->rt_rq;
+}
+
+static inline struct rq *rq_of_rt_se(struct sched_rt_entity *rt_se)
+{
+	struct rt_rq *rt_rq = rt_se->rt_rq;
+
+	return rt_rq->rq;
+}
+
+void unregister_rt_sched_group(struct task_group *tg)
+{
+	if (tg->rt_se)
+		destroy_rt_bandwidth(&tg->rt_bandwidth);
+
+}
+
+void free_rt_sched_group(struct task_group *tg)
+{
+	int i;
+
+	for_each_possible_cpu(i) {
+		if (tg->rt_rq)
+			kfree(tg->rt_rq[i]);
+		if (tg->rt_se)
+			kfree(tg->rt_se[i]);
+	}
+
+	kfree(tg->rt_rq);
+	kfree(tg->rt_se);
+}
+
+void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
+		struct sched_rt_entity *rt_se, int cpu,
+		struct sched_rt_entity *parent)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	rt_rq->highest_prio.curr = MAX_RT_PRIO-1;
+	rt_rq->rt_nr_boosted = 0;
+	rt_rq->rq = rq;
+	rt_rq->tg = tg;
+
+	tg->rt_rq[cpu] = rt_rq;
+	tg->rt_se[cpu] = rt_se;
+
+	if (!rt_se)
+		return;
+
+	if (!parent)
+		rt_se->rt_rq = &rq->rt;
+	else
+		rt_se->rt_rq = parent->my_q;
+
+	rt_se->my_q = rt_rq;
+	rt_se->parent = parent;
+	INIT_LIST_HEAD(&rt_se->run_list);
+}
+
+int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
+{
+	struct rt_rq *rt_rq;
+	struct sched_rt_entity *rt_se;
+	int i;
+
+	tg->rt_rq = kcalloc(nr_cpu_ids, sizeof(rt_rq), GFP_KERNEL);
+	if (!tg->rt_rq)
+		goto err;
+	tg->rt_se = kcalloc(nr_cpu_ids, sizeof(rt_se), GFP_KERNEL);
+	if (!tg->rt_se)
+		goto err;
+
+	init_rt_bandwidth(&tg->rt_bandwidth,
+			ktime_to_ns(def_rt_bandwidth.rt_period), 0);
+
+	for_each_possible_cpu(i) {
+		rt_rq = kzalloc_node(sizeof(struct rt_rq),
+				     GFP_KERNEL, cpu_to_node(i));
+		if (!rt_rq)
+			goto err;
+
+		rt_se = kzalloc_node(sizeof(struct sched_rt_entity),
+				     GFP_KERNEL, cpu_to_node(i));
+		if (!rt_se)
+			goto err_free_rq;
+
+		init_rt_rq(rt_rq);
+		rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
+		init_tg_rt_entry(tg, rt_rq, rt_se, i, parent->rt_se[i]);
+	}
+
+	return 1;
+
+err_free_rq:
+	kfree(rt_rq);
+err:
+	return 0;
+}
+
+#else /* CONFIG_RT_GROUP_SCHED */
+
+#define rt_entity_is_task(rt_se) (1)
+
+static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
+{
+	return container_of(rt_se, struct task_struct, rt);
+}
+
+static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
+{
+	return container_of(rt_rq, struct rq, rt);
+}
+
+static inline struct rq *rq_of_rt_se(struct sched_rt_entity *rt_se)
+{
+	struct task_struct *p = rt_task_of(rt_se);
+
+	return task_rq(p);
+}
+
+static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
+{
+	struct rq *rq = rq_of_rt_se(rt_se);
+
+	return &rq->rt;
+}
+
+void unregister_rt_sched_group(struct task_group *tg) { }
+
+void free_rt_sched_group(struct task_group *tg) { }
+
+int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
+{
+	return 1;
+}
+#endif /* CONFIG_RT_GROUP_SCHED */
+
+#ifdef CONFIG_SMP
+
+static inline bool need_pull_rt_task(struct rq *rq, struct task_struct *prev)
+{
+	/* Try to pull RT tasks here if we lower this rq's prio */
+	return rq->online && rq->rt.highest_prio.curr > prev->prio;
+}
+
+static inline int rt_overloaded(struct rq *rq)
+{
+	return atomic_read(&rq->rd->rto_count);
+}
+
+static inline void rt_set_overload(struct rq *rq)
+{
+	if (!rq->online)
+		return;
+
+	cpumask_set_cpu(rq->cpu, rq->rd->rto_mask);
+	/*
+	 * Make sure the mask is visible before we set
+	 * the overload count. That is checked to determine
+	 * if we should look at the mask. It would be a shame
+	 * if we looked at the mask, but the mask was not
+	 * updated yet.
+	 *
+	 * Matched by the barrier in pull_rt_task().
+	 */
+	smp_wmb();
+	atomic_inc(&rq->rd->rto_count);
+}
+
+static inline void rt_clear_overload(struct rq *rq)
+{
+	if (!rq->online)
+		return;
+
+	/* the order here really doesn't matter */
+	atomic_dec(&rq->rd->rto_count);
+	cpumask_clear_cpu(rq->cpu, rq->rd->rto_mask);
+}
+
+static void update_rt_migration(struct rt_rq *rt_rq)
+{
+	if (rt_rq->rt_nr_migratory && rt_rq->rt_nr_total > 1) {
+		if (!rt_rq->overloaded) {
+			rt_set_overload(rq_of_rt_rq(rt_rq));
+			rt_rq->overloaded = 1;
+		}
+	} else if (rt_rq->overloaded) {
+		rt_clear_overload(rq_of_rt_rq(rt_rq));
+		rt_rq->overloaded = 0;
+	}
+}
+
+static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+	struct task_struct *p;
+
+	if (!rt_entity_is_task(rt_se))
+		return;
+
+	p = rt_task_of(rt_se);
+	rt_rq = &rq_of_rt_rq(rt_rq)->rt;
+
+	rt_rq->rt_nr_total++;
+	if (p->nr_cpus_allowed > 1)
+		rt_rq->rt_nr_migratory++;
+
+	update_rt_migration(rt_rq);
+}
+
+static void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+	struct task_struct *p;
+
+	if (!rt_entity_is_task(rt_se))
+		return;
+
+	p = rt_task_of(rt_se);
+	rt_rq = &rq_of_rt_rq(rt_rq)->rt;
+
+	rt_rq->rt_nr_total--;
+	if (p->nr_cpus_allowed > 1)
+		rt_rq->rt_nr_migratory--;
+
+	update_rt_migration(rt_rq);
+}
+
+static inline int has_pushable_tasks(struct rq *rq)
+{
+	return !plist_head_empty(&rq->rt.pushable_tasks);
+}
+
+static DEFINE_PER_CPU(struct balance_callback, rt_push_head);
+static DEFINE_PER_CPU(struct balance_callback, rt_pull_head);
+
+static void push_rt_tasks(struct rq *);
+static void pull_rt_task(struct rq *);
+
+static inline void rt_queue_push_tasks(struct rq *rq)
+{
+	if (!has_pushable_tasks(rq))
+		return;
+
+	queue_balance_callback(rq, &per_cpu(rt_push_head, rq->cpu), push_rt_tasks);
+}
+
+static inline void rt_queue_pull_task(struct rq *rq)
+{
+	queue_balance_callback(rq, &per_cpu(rt_pull_head, rq->cpu), pull_rt_task);
+}
+
+static void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
+{
+	plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
+	plist_node_init(&p->pushable_tasks, p->prio);
+	plist_add(&p->pushable_tasks, &rq->rt.pushable_tasks);
+
+	/* Update the highest prio pushable task */
+	if (p->prio < rq->rt.highest_prio.next)
+		rq->rt.highest_prio.next = p->prio;
+}
+
+static void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
+{
+	plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
+
+	/* Update the new highest prio pushable task */
+	if (has_pushable_tasks(rq)) {
+		p = plist_first_entry(&rq->rt.pushable_tasks,
+				      struct task_struct, pushable_tasks);
+		rq->rt.highest_prio.next = p->prio;
+	} else {
+		rq->rt.highest_prio.next = MAX_RT_PRIO-1;
+	}
+}
+
+#else
+
+static inline void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
+{
+}
+
+static inline void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
+{
+}
+
+static inline
+void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+}
+
+static inline
+void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+}
+
+static inline void rt_queue_push_tasks(struct rq *rq)
+{
+}
+#endif /* CONFIG_SMP */
+
+static void enqueue_top_rt_rq(struct rt_rq *rt_rq);
+static void dequeue_top_rt_rq(struct rt_rq *rt_rq, unsigned int count);
+
+static inline int on_rt_rq(struct sched_rt_entity *rt_se)
+{
+	return rt_se->on_rq;
+}
+
+#ifdef CONFIG_UCLAMP_TASK
+/*
+ * Verify the fitness of task @p to run on @cpu taking into account the uclamp
+ * settings.
+ *
+ * This check is only important for heterogeneous systems where uclamp_min value
+ * is higher than the capacity of a @cpu. For non-heterogeneous system this
+ * function will always return true.
+ *
+ * The function will return true if the capacity of the @cpu is >= the
+ * uclamp_min and false otherwise.
+ *
+ * Note that uclamp_min will be clamped to uclamp_max if uclamp_min
+ * > uclamp_max.
+ */
+static inline bool rt_task_fits_capacity(struct task_struct *p, int cpu)
+{
+	unsigned int min_cap;
+	unsigned int max_cap;
+	unsigned int cpu_cap;
+
+	/* Only heterogeneous systems can benefit from this check */
+	if (!sched_asym_cpucap_active())
+		return true;
+
+	min_cap = uclamp_eff_value(p, UCLAMP_MIN);
+	max_cap = uclamp_eff_value(p, UCLAMP_MAX);
+
+	cpu_cap = capacity_orig_of(cpu);
+
+	return cpu_cap >= min(min_cap, max_cap);
+}
+#else
+static inline bool rt_task_fits_capacity(struct task_struct *p, int cpu)
+{
+	return true;
+}
+#endif
+
+#ifdef CONFIG_RT_GROUP_SCHED
+
+static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
+{
+	if (!rt_rq->tg)
+		return RUNTIME_INF;
+
+	return rt_rq->rt_runtime;
+}
+
+static inline u64 sched_rt_period(struct rt_rq *rt_rq)
+{
+	return ktime_to_ns(rt_rq->tg->rt_bandwidth.rt_period);
+}
+
+typedef struct task_group *rt_rq_iter_t;
+
+static inline struct task_group *next_task_group(struct task_group *tg)
+{
+	do {
+		tg = list_entry_rcu(tg->list.next,
+			typeof(struct task_group), list);
+	} while (&tg->list != &task_groups && task_group_is_autogroup(tg));
+
+	if (&tg->list == &task_groups)
+		tg = NULL;
+
+	return tg;
+}
+
+#define for_each_rt_rq(rt_rq, iter, rq)					\
+	for (iter = container_of(&task_groups, typeof(*iter), list);	\
+		(iter = next_task_group(iter)) &&			\
+		(rt_rq = iter->rt_rq[cpu_of(rq)]);)
+
+#define for_each_sched_rt_entity(rt_se) \
+	for (; rt_se; rt_se = rt_se->parent)
+
+static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
+{
+	return rt_se->my_q;
+}
+
+static void enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags);
+static void dequeue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags);
+
+static void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
+{
+	struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr;
+	struct rq *rq = rq_of_rt_rq(rt_rq);
+	struct sched_rt_entity *rt_se;
+
+	int cpu = cpu_of(rq);
+
+	rt_se = rt_rq->tg->rt_se[cpu];
+
+	if (rt_rq->rt_nr_running) {
+		if (!rt_se)
+			enqueue_top_rt_rq(rt_rq);
+		else if (!on_rt_rq(rt_se))
+			enqueue_rt_entity(rt_se, 0);
+
+		if (rt_rq->highest_prio.curr < curr->prio)
+			resched_curr(rq);
+	}
+}
+
+static void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
+{
+	struct sched_rt_entity *rt_se;
+	int cpu = cpu_of(rq_of_rt_rq(rt_rq));
+
+	rt_se = rt_rq->tg->rt_se[cpu];
+
+	if (!rt_se) {
+		dequeue_top_rt_rq(rt_rq, rt_rq->rt_nr_running);
+		/* Kick cpufreq (see the comment in kernel/sched/sched.h). */
+		cpufreq_update_util(rq_of_rt_rq(rt_rq), 0);
+	}
+	else if (on_rt_rq(rt_se))
+		dequeue_rt_entity(rt_se, 0);
+}
+
+static inline int rt_rq_throttled(struct rt_rq *rt_rq)
+{
+	return rt_rq->rt_throttled && !rt_rq->rt_nr_boosted;
+}
+
+static int rt_se_boosted(struct sched_rt_entity *rt_se)
+{
+	struct rt_rq *rt_rq = group_rt_rq(rt_se);
+	struct task_struct *p;
+
+	if (rt_rq)
+		return !!rt_rq->rt_nr_boosted;
+
+	p = rt_task_of(rt_se);
+	return p->prio != p->normal_prio;
+}
+
+#ifdef CONFIG_SMP
+static inline const struct cpumask *sched_rt_period_mask(void)
+{
+	return this_rq()->rd->span;
+}
+#else
+static inline const struct cpumask *sched_rt_period_mask(void)
+{
+	return cpu_online_mask;
+}
+#endif
+
+static inline
+struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
+{
+	return container_of(rt_b, struct task_group, rt_bandwidth)->rt_rq[cpu];
+}
+
+static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
+{
+	return &rt_rq->tg->rt_bandwidth;
+}
+
+#else /* !CONFIG_RT_GROUP_SCHED */
+
+static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
+{
+	return rt_rq->rt_runtime;
+}
+
+static inline u64 sched_rt_period(struct rt_rq *rt_rq)
+{
+	return ktime_to_ns(def_rt_bandwidth.rt_period);
+}
+
+typedef struct rt_rq *rt_rq_iter_t;
+
+#define for_each_rt_rq(rt_rq, iter, rq) \
+	for ((void) iter, rt_rq = &rq->rt; rt_rq; rt_rq = NULL)
+
+#define for_each_sched_rt_entity(rt_se) \
+	for (; rt_se; rt_se = NULL)
+
+static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
+{
+	return NULL;
+}
+
+static inline void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
+{
+	struct rq *rq = rq_of_rt_rq(rt_rq);
+
+	if (!rt_rq->rt_nr_running)
+		return;
+
+	enqueue_top_rt_rq(rt_rq);
+	resched_curr(rq);
+}
+
+static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
+{
+	dequeue_top_rt_rq(rt_rq, rt_rq->rt_nr_running);
+}
+
+static inline int rt_rq_throttled(struct rt_rq *rt_rq)
+{
+	return rt_rq->rt_throttled;
+}
+
+static inline const struct cpumask *sched_rt_period_mask(void)
+{
+	return cpu_online_mask;
+}
+
+static inline
+struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
+{
+	return &cpu_rq(cpu)->rt;
+}
+
+static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
+{
+	return &def_rt_bandwidth;
+}
+
+#endif /* CONFIG_RT_GROUP_SCHED */
+
+bool sched_rt_bandwidth_account(struct rt_rq *rt_rq)
+{
+	struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
+
+	return (hrtimer_active(&rt_b->rt_period_timer) ||
+		rt_rq->rt_time < rt_b->rt_runtime);
+}
+
+#ifdef CONFIG_SMP
+/*
+ * We ran out of runtime, see if we can borrow some from our neighbours.
+ */
+static void do_balance_runtime(struct rt_rq *rt_rq)
+{
+	struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
+	struct root_domain *rd = rq_of_rt_rq(rt_rq)->rd;
+	int i, weight;
+	u64 rt_period;
+
+	weight = cpumask_weight(rd->span);
+
+	raw_spin_lock(&rt_b->rt_runtime_lock);
+	rt_period = ktime_to_ns(rt_b->rt_period);
+	for_each_cpu(i, rd->span) {
+		struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
+		s64 diff;
+
+		if (iter == rt_rq)
+			continue;
+
+		raw_spin_lock(&iter->rt_runtime_lock);
+		/*
+		 * Either all rqs have inf runtime and there's nothing to steal
+		 * or __disable_runtime() below sets a specific rq to inf to
+		 * indicate its been disabled and disallow stealing.
+		 */
+		if (iter->rt_runtime == RUNTIME_INF)
+			goto next;
+
+		/*
+		 * From runqueues with spare time, take 1/n part of their
+		 * spare time, but no more than our period.
+		 */
+		diff = iter->rt_runtime - iter->rt_time;
+		if (diff > 0) {
+			diff = div_u64((u64)diff, weight);
+			if (rt_rq->rt_runtime + diff > rt_period)
+				diff = rt_period - rt_rq->rt_runtime;
+			iter->rt_runtime -= diff;
+			rt_rq->rt_runtime += diff;
+			if (rt_rq->rt_runtime == rt_period) {
+				raw_spin_unlock(&iter->rt_runtime_lock);
+				break;
+			}
+		}
+next:
+		raw_spin_unlock(&iter->rt_runtime_lock);
+	}
+	raw_spin_unlock(&rt_b->rt_runtime_lock);
+}
+
+/*
+ * Ensure this RQ takes back all the runtime it lend to its neighbours.
+ */
+static void __disable_runtime(struct rq *rq)
+{
+	struct root_domain *rd = rq->rd;
+	rt_rq_iter_t iter;
+	struct rt_rq *rt_rq;
+
+	if (unlikely(!scheduler_running))
+		return;
+
+	for_each_rt_rq(rt_rq, iter, rq) {
+		struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
+		s64 want;
+		int i;
+
+		raw_spin_lock(&rt_b->rt_runtime_lock);
+		raw_spin_lock(&rt_rq->rt_runtime_lock);
+		/*
+		 * Either we're all inf and nobody needs to borrow, or we're
+		 * already disabled and thus have nothing to do, or we have
+		 * exactly the right amount of runtime to take out.
+		 */
+		if (rt_rq->rt_runtime == RUNTIME_INF ||
+				rt_rq->rt_runtime == rt_b->rt_runtime)
+			goto balanced;
+		raw_spin_unlock(&rt_rq->rt_runtime_lock);
+
+		/*
+		 * Calculate the difference between what we started out with
+		 * and what we current have, that's the amount of runtime
+		 * we lend and now have to reclaim.
+		 */
+		want = rt_b->rt_runtime - rt_rq->rt_runtime;
+
+		/*
+		 * Greedy reclaim, take back as much as we can.
+		 */
+		for_each_cpu(i, rd->span) {
+			struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
+			s64 diff;
+
+			/*
+			 * Can't reclaim from ourselves or disabled runqueues.
+			 */
+			if (iter == rt_rq || iter->rt_runtime == RUNTIME_INF)
+				continue;
+
+			raw_spin_lock(&iter->rt_runtime_lock);
+			if (want > 0) {
+				diff = min_t(s64, iter->rt_runtime, want);
+				iter->rt_runtime -= diff;
+				want -= diff;
+			} else {
+				iter->rt_runtime -= want;
+				want -= want;
+			}
+			raw_spin_unlock(&iter->rt_runtime_lock);
+
+			if (!want)
+				break;
+		}
+
+		raw_spin_lock(&rt_rq->rt_runtime_lock);
+		/*
+		 * We cannot be left wanting - that would mean some runtime
+		 * leaked out of the system.
+		 */
+		WARN_ON_ONCE(want);
+balanced:
+		/*
+		 * Disable all the borrow logic by pretending we have inf
+		 * runtime - in which case borrowing doesn't make sense.
+		 */
+		rt_rq->rt_runtime = RUNTIME_INF;
+		rt_rq->rt_throttled = 0;
+		raw_spin_unlock(&rt_rq->rt_runtime_lock);
+		raw_spin_unlock(&rt_b->rt_runtime_lock);
+
+		/* Make rt_rq available for pick_next_task() */
+		sched_rt_rq_enqueue(rt_rq);
+	}
+}
+
+static void __enable_runtime(struct rq *rq)
+{
+	rt_rq_iter_t iter;
+	struct rt_rq *rt_rq;
+
+	if (unlikely(!scheduler_running))
+		return;
+
+	/*
+	 * Reset each runqueue's bandwidth settings
+	 */
+	for_each_rt_rq(rt_rq, iter, rq) {
+		struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
+
+		raw_spin_lock(&rt_b->rt_runtime_lock);
+		raw_spin_lock(&rt_rq->rt_runtime_lock);
+		rt_rq->rt_runtime = rt_b->rt_runtime;
+		rt_rq->rt_time = 0;
+		rt_rq->rt_throttled = 0;
+		raw_spin_unlock(&rt_rq->rt_runtime_lock);
+		raw_spin_unlock(&rt_b->rt_runtime_lock);
+	}
+}
+
+static void balance_runtime(struct rt_rq *rt_rq)
+{
+	if (!sched_feat(RT_RUNTIME_SHARE))
+		return;
+
+	if (rt_rq->rt_time > rt_rq->rt_runtime) {
+		raw_spin_unlock(&rt_rq->rt_runtime_lock);
+		do_balance_runtime(rt_rq);
+		raw_spin_lock(&rt_rq->rt_runtime_lock);
+	}
+}
+#else /* !CONFIG_SMP */
+static inline void balance_runtime(struct rt_rq *rt_rq) {}
+#endif /* CONFIG_SMP */
+
+static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
+{
+	int i, idle = 1, throttled = 0;
+	const struct cpumask *span;
+
+	span = sched_rt_period_mask();
+#ifdef CONFIG_RT_GROUP_SCHED
+	/*
+	 * FIXME: isolated CPUs should really leave the root task group,
+	 * whether they are isolcpus or were isolated via cpusets, lest
+	 * the timer run on a CPU which does not service all runqueues,
+	 * potentially leaving other CPUs indefinitely throttled.  If
+	 * isolation is really required, the user will turn the throttle
+	 * off to kill the perturbations it causes anyway.  Meanwhile,
+	 * this maintains functionality for boot and/or troubleshooting.
+	 */
+	if (rt_b == &root_task_group.rt_bandwidth)
+		span = cpu_online_mask;
+#endif
+	for_each_cpu(i, span) {
+		int enqueue = 0;
+		struct rt_rq *rt_rq = sched_rt_period_rt_rq(rt_b, i);
+		struct rq *rq = rq_of_rt_rq(rt_rq);
+		struct rq_flags rf;
+		int skip;
+
+		/*
+		 * When span == cpu_online_mask, taking each rq->lock
+		 * can be time-consuming. Try to avoid it when possible.
+		 */
+		raw_spin_lock(&rt_rq->rt_runtime_lock);
+		if (!sched_feat(RT_RUNTIME_SHARE) && rt_rq->rt_runtime != RUNTIME_INF)
+			rt_rq->rt_runtime = rt_b->rt_runtime;
+		skip = !rt_rq->rt_time && !rt_rq->rt_nr_running;
+		raw_spin_unlock(&rt_rq->rt_runtime_lock);
+		if (skip)
+			continue;
+
+		rq_lock(rq, &rf);
+		update_rq_clock(rq);
+
+		if (rt_rq->rt_time) {
+			u64 runtime;
+
+			raw_spin_lock(&rt_rq->rt_runtime_lock);
+			if (rt_rq->rt_throttled)
+				balance_runtime(rt_rq);
+			runtime = rt_rq->rt_runtime;
+			rt_rq->rt_time -= min(rt_rq->rt_time, overrun*runtime);
+			if (rt_rq->rt_throttled && rt_rq->rt_time < runtime) {
+				rt_rq->rt_throttled = 0;
+				enqueue = 1;
+
+				/*
+				 * When we're idle and a woken (rt) task is
+				 * throttled check_preempt_curr() will set
+				 * skip_update and the time between the wakeup
+				 * and this unthrottle will get accounted as
+				 * 'runtime'.
+				 */
+				if (rt_rq->rt_nr_running && rq->curr == rq->idle)
+					rq_clock_cancel_skipupdate(rq);
+			}
+			if (rt_rq->rt_time || rt_rq->rt_nr_running)
+				idle = 0;
+			raw_spin_unlock(&rt_rq->rt_runtime_lock);
+		} else if (rt_rq->rt_nr_running) {
+			idle = 0;
+			if (!rt_rq_throttled(rt_rq))
+				enqueue = 1;
+		}
+		if (rt_rq->rt_throttled)
+			throttled = 1;
+
+		if (enqueue)
+			sched_rt_rq_enqueue(rt_rq);
+		rq_unlock(rq, &rf);
+	}
+
+	if (!throttled && (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF))
+		return 1;
+
+	return idle;
+}
+
+static inline int rt_se_prio(struct sched_rt_entity *rt_se)
+{
+#ifdef CONFIG_RT_GROUP_SCHED
+	struct rt_rq *rt_rq = group_rt_rq(rt_se);
+
+	if (rt_rq)
+		return rt_rq->highest_prio.curr;
+#endif
+
+	return rt_task_of(rt_se)->prio;
+}
+
+static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
+{
+	u64 runtime = sched_rt_runtime(rt_rq);
+
+	if (rt_rq->rt_throttled)
+		return rt_rq_throttled(rt_rq);
+
+	if (runtime >= sched_rt_period(rt_rq))
+		return 0;
+
+	balance_runtime(rt_rq);
+	runtime = sched_rt_runtime(rt_rq);
+	if (runtime == RUNTIME_INF)
+		return 0;
+
+	if (rt_rq->rt_time > runtime) {
+		struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
+
+		/*
+		 * Don't actually throttle groups that have no runtime assigned
+		 * but accrue some time due to boosting.
+		 */
+		if (likely(rt_b->rt_runtime)) {
+			rt_rq->rt_throttled = 1;
+			printk_deferred_once("sched: RT throttling activated\n");
+		} else {
+			/*
+			 * In case we did anyway, make it go away,
+			 * replenishment is a joke, since it will replenish us
+			 * with exactly 0 ns.
+			 */
+			rt_rq->rt_time = 0;
+		}
+
+		if (rt_rq_throttled(rt_rq)) {
+			sched_rt_rq_dequeue(rt_rq);
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Update the current task's runtime statistics. Skip current tasks that
+ * are not in our scheduling class.
+ */
+static void update_curr_rt(struct rq *rq)
+{
+	struct task_struct *curr = rq->curr;
+	struct sched_rt_entity *rt_se = &curr->rt;
+	u64 delta_exec;
+	u64 now;
+
+	if (curr->sched_class != &rt_sched_class)
+		return;
+
+	now = rq_clock_task(rq);
+	delta_exec = now - curr->se.exec_start;
+	if (unlikely((s64)delta_exec <= 0))
+		return;
+
+	schedstat_set(curr->stats.exec_max,
+		      max(curr->stats.exec_max, delta_exec));
+
+	trace_sched_stat_runtime(curr, delta_exec, 0);
+
+	update_current_exec_runtime(curr, now, delta_exec);
+
+	if (!rt_bandwidth_enabled())
+		return;
+
+	for_each_sched_rt_entity(rt_se) {
+		struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
+		int exceeded;
+
+		if (sched_rt_runtime(rt_rq) != RUNTIME_INF) {
+			raw_spin_lock(&rt_rq->rt_runtime_lock);
+			rt_rq->rt_time += delta_exec;
+			exceeded = sched_rt_runtime_exceeded(rt_rq);
+			if (exceeded)
+				resched_curr(rq);
+			raw_spin_unlock(&rt_rq->rt_runtime_lock);
+			if (exceeded)
+				do_start_rt_bandwidth(sched_rt_bandwidth(rt_rq));
+		}
+	}
+}
+
+static void
+dequeue_top_rt_rq(struct rt_rq *rt_rq, unsigned int count)
+{
+	struct rq *rq = rq_of_rt_rq(rt_rq);
+
+	BUG_ON(&rq->rt != rt_rq);
+
+	if (!rt_rq->rt_queued)
+		return;
+
+	BUG_ON(!rq->nr_running);
+
+	sub_nr_running(rq, count);
+	rt_rq->rt_queued = 0;
+
+}
+
+static void
+enqueue_top_rt_rq(struct rt_rq *rt_rq)
+{
+	struct rq *rq = rq_of_rt_rq(rt_rq);
+
+	BUG_ON(&rq->rt != rt_rq);
+
+	if (rt_rq->rt_queued)
+		return;
+
+	if (rt_rq_throttled(rt_rq))
+		return;
+
+	if (rt_rq->rt_nr_running) {
+		add_nr_running(rq, rt_rq->rt_nr_running);
+		rt_rq->rt_queued = 1;
+	}
+
+	/* Kick cpufreq (see the comment in kernel/sched/sched.h). */
+	cpufreq_update_util(rq, 0);
+}
+
+#if defined CONFIG_SMP
+
+static void
+inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
+{
+	struct rq *rq = rq_of_rt_rq(rt_rq);
+
+#ifdef CONFIG_RT_GROUP_SCHED
+	/*
+	 * Change rq's cpupri only if rt_rq is the top queue.
+	 */
+	if (&rq->rt != rt_rq)
+		return;
+#endif
+	if (rq->online && prio < prev_prio)
+		cpupri_set(&rq->rd->cpupri, rq->cpu, prio);
+}
+
+static void
+dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
+{
+	struct rq *rq = rq_of_rt_rq(rt_rq);
+
+#ifdef CONFIG_RT_GROUP_SCHED
+	/*
+	 * Change rq's cpupri only if rt_rq is the top queue.
+	 */
+	if (&rq->rt != rt_rq)
+		return;
+#endif
+	if (rq->online && rt_rq->highest_prio.curr != prev_prio)
+		cpupri_set(&rq->rd->cpupri, rq->cpu, rt_rq->highest_prio.curr);
+}
+
+#else /* CONFIG_SMP */
+
+static inline
+void inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
+static inline
+void dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
+
+#endif /* CONFIG_SMP */
+
+#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
+static void
+inc_rt_prio(struct rt_rq *rt_rq, int prio)
+{
+	int prev_prio = rt_rq->highest_prio.curr;
+
+	if (prio < prev_prio)
+		rt_rq->highest_prio.curr = prio;
+
+	inc_rt_prio_smp(rt_rq, prio, prev_prio);
+}
+
+static void
+dec_rt_prio(struct rt_rq *rt_rq, int prio)
+{
+	int prev_prio = rt_rq->highest_prio.curr;
+
+	if (rt_rq->rt_nr_running) {
+
+		WARN_ON(prio < prev_prio);
+
+		/*
+		 * This may have been our highest task, and therefore
+		 * we may have some recomputation to do
+		 */
+		if (prio == prev_prio) {
+			struct rt_prio_array *array = &rt_rq->active;
+
+			rt_rq->highest_prio.curr =
+				sched_find_first_bit(array->bitmap);
+		}
+
+	} else {
+		rt_rq->highest_prio.curr = MAX_RT_PRIO-1;
+	}
+
+	dec_rt_prio_smp(rt_rq, prio, prev_prio);
+}
+
+#else
+
+static inline void inc_rt_prio(struct rt_rq *rt_rq, int prio) {}
+static inline void dec_rt_prio(struct rt_rq *rt_rq, int prio) {}
+
+#endif /* CONFIG_SMP || CONFIG_RT_GROUP_SCHED */
+
+#ifdef CONFIG_RT_GROUP_SCHED
+
+static void
+inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+	if (rt_se_boosted(rt_se))
+		rt_rq->rt_nr_boosted++;
+
+	if (rt_rq->tg)
+		start_rt_bandwidth(&rt_rq->tg->rt_bandwidth);
+}
+
+static void
+dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+	if (rt_se_boosted(rt_se))
+		rt_rq->rt_nr_boosted--;
+
+	WARN_ON(!rt_rq->rt_nr_running && rt_rq->rt_nr_boosted);
+}
+
+#else /* CONFIG_RT_GROUP_SCHED */
+
+static void
+inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+	start_rt_bandwidth(&def_rt_bandwidth);
+}
+
+static inline
+void dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) {}
+
+#endif /* CONFIG_RT_GROUP_SCHED */
+
+static inline
+unsigned int rt_se_nr_running(struct sched_rt_entity *rt_se)
+{
+	struct rt_rq *group_rq = group_rt_rq(rt_se);
+
+	if (group_rq)
+		return group_rq->rt_nr_running;
+	else
+		return 1;
+}
+
+static inline
+unsigned int rt_se_rr_nr_running(struct sched_rt_entity *rt_se)
+{
+	struct rt_rq *group_rq = group_rt_rq(rt_se);
+	struct task_struct *tsk;
+
+	if (group_rq)
+		return group_rq->rr_nr_running;
+
+	tsk = rt_task_of(rt_se);
+
+	return (tsk->policy == SCHED_RR) ? 1 : 0;
+}
+
+static inline
+void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+	int prio = rt_se_prio(rt_se);
+
+	WARN_ON(!rt_prio(prio));
+	rt_rq->rt_nr_running += rt_se_nr_running(rt_se);
+	rt_rq->rr_nr_running += rt_se_rr_nr_running(rt_se);
+
+	inc_rt_prio(rt_rq, prio);
+	inc_rt_migration(rt_se, rt_rq);
+	inc_rt_group(rt_se, rt_rq);
+}
+
+static inline
+void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+	WARN_ON(!rt_prio(rt_se_prio(rt_se)));
+	WARN_ON(!rt_rq->rt_nr_running);
+	rt_rq->rt_nr_running -= rt_se_nr_running(rt_se);
+	rt_rq->rr_nr_running -= rt_se_rr_nr_running(rt_se);
+
+	dec_rt_prio(rt_rq, rt_se_prio(rt_se));
+	dec_rt_migration(rt_se, rt_rq);
+	dec_rt_group(rt_se, rt_rq);
+}
+
+/*
+ * Change rt_se->run_list location unless SAVE && !MOVE
+ *
+ * assumes ENQUEUE/DEQUEUE flags match
+ */
+static inline bool move_entity(unsigned int flags)
+{
+	if ((flags & (DEQUEUE_SAVE | DEQUEUE_MOVE)) == DEQUEUE_SAVE)
+		return false;
+
+	return true;
+}
+
+static void __delist_rt_entity(struct sched_rt_entity *rt_se, struct rt_prio_array *array)
+{
+	list_del_init(&rt_se->run_list);
+
+	if (list_empty(array->queue + rt_se_prio(rt_se)))
+		__clear_bit(rt_se_prio(rt_se), array->bitmap);
+
+	rt_se->on_list = 0;
+}
+
+static inline struct sched_statistics *
+__schedstats_from_rt_se(struct sched_rt_entity *rt_se)
+{
+#ifdef CONFIG_RT_GROUP_SCHED
+	/* schedstats is not supported for rt group. */
+	if (!rt_entity_is_task(rt_se))
+		return NULL;
+#endif
+
+	return &rt_task_of(rt_se)->stats;
+}
+
+static inline void
+update_stats_wait_start_rt(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se)
+{
+	struct sched_statistics *stats;
+	struct task_struct *p = NULL;
+
+	if (!schedstat_enabled())
+		return;
+
+	if (rt_entity_is_task(rt_se))
+		p = rt_task_of(rt_se);
+
+	stats = __schedstats_from_rt_se(rt_se);
+	if (!stats)
+		return;
+
+	__update_stats_wait_start(rq_of_rt_rq(rt_rq), p, stats);
+}
+
+static inline void
+update_stats_enqueue_sleeper_rt(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se)
+{
+	struct sched_statistics *stats;
+	struct task_struct *p = NULL;
+
+	if (!schedstat_enabled())
+		return;
+
+	if (rt_entity_is_task(rt_se))
+		p = rt_task_of(rt_se);
+
+	stats = __schedstats_from_rt_se(rt_se);
+	if (!stats)
+		return;
+
+	__update_stats_enqueue_sleeper(rq_of_rt_rq(rt_rq), p, stats);
+}
+
+static inline void
+update_stats_enqueue_rt(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se,
+			int flags)
+{
+	if (!schedstat_enabled())
+		return;
+
+	if (flags & ENQUEUE_WAKEUP)
+		update_stats_enqueue_sleeper_rt(rt_rq, rt_se);
+}
+
+static inline void
+update_stats_wait_end_rt(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se)
+{
+	struct sched_statistics *stats;
+	struct task_struct *p = NULL;
+
+	if (!schedstat_enabled())
+		return;
+
+	if (rt_entity_is_task(rt_se))
+		p = rt_task_of(rt_se);
+
+	stats = __schedstats_from_rt_se(rt_se);
+	if (!stats)
+		return;
+
+	__update_stats_wait_end(rq_of_rt_rq(rt_rq), p, stats);
+}
+
+static inline void
+update_stats_dequeue_rt(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se,
+			int flags)
+{
+	struct task_struct *p = NULL;
+
+	if (!schedstat_enabled())
+		return;
+
+	if (rt_entity_is_task(rt_se))
+		p = rt_task_of(rt_se);
+
+	if ((flags & DEQUEUE_SLEEP) && p) {
+		unsigned int state;
+
+		state = READ_ONCE(p->__state);
+		if (state & TASK_INTERRUPTIBLE)
+			__schedstat_set(p->stats.sleep_start,
+					rq_clock(rq_of_rt_rq(rt_rq)));
+
+		if (state & TASK_UNINTERRUPTIBLE)
+			__schedstat_set(p->stats.block_start,
+					rq_clock(rq_of_rt_rq(rt_rq)));
+	}
+}
+
+static void __enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
+{
+	struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
+	struct rt_prio_array *array = &rt_rq->active;
+	struct rt_rq *group_rq = group_rt_rq(rt_se);
+	struct list_head *queue = array->queue + rt_se_prio(rt_se);
+
+	/*
+	 * Don't enqueue the group if its throttled, or when empty.
+	 * The latter is a consequence of the former when a child group
+	 * get throttled and the current group doesn't have any other
+	 * active members.
+	 */
+	if (group_rq && (rt_rq_throttled(group_rq) || !group_rq->rt_nr_running)) {
+		if (rt_se->on_list)
+			__delist_rt_entity(rt_se, array);
+		return;
+	}
+
+	if (move_entity(flags)) {
+		WARN_ON_ONCE(rt_se->on_list);
+		if (flags & ENQUEUE_HEAD)
+			list_add(&rt_se->run_list, queue);
+		else
+			list_add_tail(&rt_se->run_list, queue);
+
+		__set_bit(rt_se_prio(rt_se), array->bitmap);
+		rt_se->on_list = 1;
+	}
+	rt_se->on_rq = 1;
+
+	inc_rt_tasks(rt_se, rt_rq);
+}
+
+static void __dequeue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
+{
+	struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
+	struct rt_prio_array *array = &rt_rq->active;
+
+	if (move_entity(flags)) {
+		WARN_ON_ONCE(!rt_se->on_list);
+		__delist_rt_entity(rt_se, array);
+	}
+	rt_se->on_rq = 0;
+
+	dec_rt_tasks(rt_se, rt_rq);
+}
+
+/*
+ * Because the prio of an upper entry depends on the lower
+ * entries, we must remove entries top - down.
+ */
+static void dequeue_rt_stack(struct sched_rt_entity *rt_se, unsigned int flags)
+{
+	struct sched_rt_entity *back = NULL;
+	unsigned int rt_nr_running;
+
+	for_each_sched_rt_entity(rt_se) {
+		rt_se->back = back;
+		back = rt_se;
+	}
+
+	rt_nr_running = rt_rq_of_se(back)->rt_nr_running;
+
+	for (rt_se = back; rt_se; rt_se = rt_se->back) {
+		if (on_rt_rq(rt_se))
+			__dequeue_rt_entity(rt_se, flags);
+	}
+
+	dequeue_top_rt_rq(rt_rq_of_se(back), rt_nr_running);
+}
+
+static void enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
+{
+	struct rq *rq = rq_of_rt_se(rt_se);
+
+	update_stats_enqueue_rt(rt_rq_of_se(rt_se), rt_se, flags);
+
+	dequeue_rt_stack(rt_se, flags);
+	for_each_sched_rt_entity(rt_se)
+		__enqueue_rt_entity(rt_se, flags);
+	enqueue_top_rt_rq(&rq->rt);
+}
+
+static void dequeue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
+{
+	struct rq *rq = rq_of_rt_se(rt_se);
+
+	update_stats_dequeue_rt(rt_rq_of_se(rt_se), rt_se, flags);
+
+	dequeue_rt_stack(rt_se, flags);
+
+	for_each_sched_rt_entity(rt_se) {
+		struct rt_rq *rt_rq = group_rt_rq(rt_se);
+
+		if (rt_rq && rt_rq->rt_nr_running)
+			__enqueue_rt_entity(rt_se, flags);
+	}
+	enqueue_top_rt_rq(&rq->rt);
+}
+
+/*
+ * Adding/removing a task to/from a priority array:
+ */
+static void
+enqueue_task_rt(struct rq *rq, struct task_struct *p, int flags)
+{
+	struct sched_rt_entity *rt_se = &p->rt;
+
+	if (flags & ENQUEUE_WAKEUP)
+		rt_se->timeout = 0;
+
+	check_schedstat_required();
+	update_stats_wait_start_rt(rt_rq_of_se(rt_se), rt_se);
+
+	enqueue_rt_entity(rt_se, flags);
+
+	if (!task_current(rq, p) && p->nr_cpus_allowed > 1)
+		enqueue_pushable_task(rq, p);
+}
+
+static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int flags)
+{
+	struct sched_rt_entity *rt_se = &p->rt;
+
+	update_curr_rt(rq);
+	dequeue_rt_entity(rt_se, flags);
+
+	dequeue_pushable_task(rq, p);
+}
+
+/*
+ * Put task to the head or the end of the run list without the overhead of
+ * dequeue followed by enqueue.
+ */
+static void
+requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se, int head)
+{
+	if (on_rt_rq(rt_se)) {
+		struct rt_prio_array *array = &rt_rq->active;
+		struct list_head *queue = array->queue + rt_se_prio(rt_se);
+
+		if (head)
+			list_move(&rt_se->run_list, queue);
+		else
+			list_move_tail(&rt_se->run_list, queue);
+	}
+}
+
+static void requeue_task_rt(struct rq *rq, struct task_struct *p, int head)
+{
+	struct sched_rt_entity *rt_se = &p->rt;
+	struct rt_rq *rt_rq;
+
+	for_each_sched_rt_entity(rt_se) {
+		rt_rq = rt_rq_of_se(rt_se);
+		requeue_rt_entity(rt_rq, rt_se, head);
+	}
+}
+
+static void yield_task_rt(struct rq *rq)
+{
+	requeue_task_rt(rq, rq->curr, 0);
+}
+
+#ifdef CONFIG_SMP
+static int find_lowest_rq(struct task_struct *task);
+
+static int
+select_task_rq_rt(struct task_struct *p, int cpu, int flags)
+{
+	struct task_struct *curr;
+	struct rq *rq;
+	bool test;
+
+	/* For anything but wake ups, just return the task_cpu */
+	if (!(flags & (WF_TTWU | WF_FORK)))
+		goto out;
+
+	rq = cpu_rq(cpu);
+
+	rcu_read_lock();
+	curr = READ_ONCE(rq->curr); /* unlocked access */
+
+	/*
+	 * If the current task on @p's runqueue is an RT task, then
+	 * try to see if we can wake this RT task up on another
+	 * runqueue. Otherwise simply start this RT task
+	 * on its current runqueue.
+	 *
+	 * We want to avoid overloading runqueues. If the woken
+	 * task is a higher priority, then it will stay on this CPU
+	 * and the lower prio task should be moved to another CPU.
+	 * Even though this will probably make the lower prio task
+	 * lose its cache, we do not want to bounce a higher task
+	 * around just because it gave up its CPU, perhaps for a
+	 * lock?
+	 *
+	 * For equal prio tasks, we just let the scheduler sort it out.
+	 *
+	 * Otherwise, just let it ride on the affined RQ and the
+	 * post-schedule router will push the preempted task away
+	 *
+	 * This test is optimistic, if we get it wrong the load-balancer
+	 * will have to sort it out.
+	 *
+	 * We take into account the capacity of the CPU to ensure it fits the
+	 * requirement of the task - which is only important on heterogeneous
+	 * systems like big.LITTLE.
+	 */
+	test = curr &&
+	       unlikely(rt_task(curr)) &&
+	       (curr->nr_cpus_allowed < 2 || curr->prio <= p->prio);
+
+	if (test || !rt_task_fits_capacity(p, cpu)) {
+		int target = find_lowest_rq(p);
+
+		/*
+		 * Bail out if we were forcing a migration to find a better
+		 * fitting CPU but our search failed.
+		 */
+		if (!test && target != -1 && !rt_task_fits_capacity(p, target))
+			goto out_unlock;
+
+		/*
+		 * Don't bother moving it if the destination CPU is
+		 * not running a lower priority task.
+		 */
+		if (target != -1 &&
+		    p->prio < cpu_rq(target)->rt.highest_prio.curr)
+			cpu = target;
+	}
+
+out_unlock:
+	rcu_read_unlock();
+
+out:
+	return cpu;
+}
+
+static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
+{
+	/*
+	 * Current can't be migrated, useless to reschedule,
+	 * let's hope p can move out.
+	 */
+	if (rq->curr->nr_cpus_allowed == 1 ||
+	    !cpupri_find(&rq->rd->cpupri, rq->curr, NULL))
+		return;
+
+	/*
+	 * p is migratable, so let's not schedule it and
+	 * see if it is pushed or pulled somewhere else.
+	 */
+	if (p->nr_cpus_allowed != 1 &&
+	    cpupri_find(&rq->rd->cpupri, p, NULL))
+		return;
+
+	/*
+	 * There appear to be other CPUs that can accept
+	 * the current task but none can run 'p', so lets reschedule
+	 * to try and push the current task away:
+	 */
+	requeue_task_rt(rq, p, 1);
+	resched_curr(rq);
+}
+
+static int balance_rt(struct rq *rq, struct task_struct *p, struct rq_flags *rf)
+{
+	if (!on_rt_rq(&p->rt) && need_pull_rt_task(rq, p)) {
+		/*
+		 * This is OK, because current is on_cpu, which avoids it being
+		 * picked for load-balance and preemption/IRQs are still
+		 * disabled avoiding further scheduler activity on it and we've
+		 * not yet started the picking loop.
+		 */
+		rq_unpin_lock(rq, rf);
+		pull_rt_task(rq);
+		rq_repin_lock(rq, rf);
+	}
+
+	return sched_stop_runnable(rq) || sched_dl_runnable(rq) || sched_rt_runnable(rq);
+}
+#endif /* CONFIG_SMP */
+
+/*
+ * Preempt the current task with a newly woken task if needed:
+ */
+static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int flags)
+{
+	if (p->prio < rq->curr->prio) {
+		resched_curr(rq);
+		return;
+	}
+
+#ifdef CONFIG_SMP
+	/*
+	 * If:
+	 *
+	 * - the newly woken task is of equal priority to the current task
+	 * - the newly woken task is non-migratable while current is migratable
+	 * - current will be preempted on the next reschedule
+	 *
+	 * we should check to see if current can readily move to a different
+	 * cpu.  If so, we will reschedule to allow the push logic to try
+	 * to move current somewhere else, making room for our non-migratable
+	 * task.
+	 */
+	if (p->prio == rq->curr->prio && !test_tsk_need_resched(rq->curr))
+		check_preempt_equal_prio(rq, p);
+#endif
+}
+
+static inline void set_next_task_rt(struct rq *rq, struct task_struct *p, bool first)
+{
+	struct sched_rt_entity *rt_se = &p->rt;
+	struct rt_rq *rt_rq = &rq->rt;
+
+	p->se.exec_start = rq_clock_task(rq);
+	if (on_rt_rq(&p->rt))
+		update_stats_wait_end_rt(rt_rq, rt_se);
+
+	/* The running task is never eligible for pushing */
+	dequeue_pushable_task(rq, p);
+
+	if (!first)
+		return;
+
+	/*
+	 * If prev task was rt, put_prev_task() has already updated the
+	 * utilization. We only care of the case where we start to schedule a
+	 * rt task
+	 */
+	if (rq->curr->sched_class != &rt_sched_class)
+		update_rt_rq_load_avg(rq_clock_pelt(rq), rq, 0);
+
+	rt_queue_push_tasks(rq);
+}
+
+static struct sched_rt_entity *pick_next_rt_entity(struct rt_rq *rt_rq)
+{
+	struct rt_prio_array *array = &rt_rq->active;
+	struct sched_rt_entity *next = NULL;
+	struct list_head *queue;
+	int idx;
+
+	idx = sched_find_first_bit(array->bitmap);
+	BUG_ON(idx >= MAX_RT_PRIO);
+
+	queue = array->queue + idx;
+	if (SCHED_WARN_ON(list_empty(queue)))
+		return NULL;
+	next = list_entry(queue->next, struct sched_rt_entity, run_list);
+
+	return next;
+}
+
+static struct task_struct *_pick_next_task_rt(struct rq *rq)
+{
+	struct sched_rt_entity *rt_se;
+	struct rt_rq *rt_rq  = &rq->rt;
+
+	do {
+		rt_se = pick_next_rt_entity(rt_rq);
+		if (unlikely(!rt_se))
+			return NULL;
+		rt_rq = group_rt_rq(rt_se);
+	} while (rt_rq);
+
+	return rt_task_of(rt_se);
+}
+
+static struct task_struct *pick_task_rt(struct rq *rq)
+{
+	struct task_struct *p;
+
+	if (!sched_rt_runnable(rq))
+		return NULL;
+
+	p = _pick_next_task_rt(rq);
+
+	return p;
+}
+
+static struct task_struct *pick_next_task_rt(struct rq *rq)
+{
+	struct task_struct *p = pick_task_rt(rq);
+
+	if (p)
+		set_next_task_rt(rq, p, true);
+
+	return p;
+}
+
+static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
+{
+	struct sched_rt_entity *rt_se = &p->rt;
+	struct rt_rq *rt_rq = &rq->rt;
+
+	if (on_rt_rq(&p->rt))
+		update_stats_wait_start_rt(rt_rq, rt_se);
+
+	update_curr_rt(rq);
+
+	update_rt_rq_load_avg(rq_clock_pelt(rq), rq, 1);
+
+	/*
+	 * The previous task needs to be made eligible for pushing
+	 * if it is still active
+	 */
+	if (on_rt_rq(&p->rt) && p->nr_cpus_allowed > 1)
+		enqueue_pushable_task(rq, p);
+}
+
+#ifdef CONFIG_SMP
+
+/* Only try algorithms three times */
+#define RT_MAX_TRIES 3
+
+static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu)
+{
+	if (!task_on_cpu(rq, p) &&
+	    cpumask_test_cpu(cpu, &p->cpus_mask))
+		return 1;
+
+	return 0;
+}
+
+/*
+ * Return the highest pushable rq's task, which is suitable to be executed
+ * on the CPU, NULL otherwise
+ */
+static struct task_struct *pick_highest_pushable_task(struct rq *rq, int cpu)
+{
+	struct plist_head *head = &rq->rt.pushable_tasks;
+	struct task_struct *p;
+
+	if (!has_pushable_tasks(rq))
+		return NULL;
+
+	plist_for_each_entry(p, head, pushable_tasks) {
+		if (pick_rt_task(rq, p, cpu))
+			return p;
+	}
+
+	return NULL;
+}
+
+static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask);
+
+static int find_lowest_rq(struct task_struct *task)
+{
+	struct sched_domain *sd;
+	struct cpumask *lowest_mask = this_cpu_cpumask_var_ptr(local_cpu_mask);
+	int this_cpu = smp_processor_id();
+	int cpu      = task_cpu(task);
+	int ret;
+
+	/* Make sure the mask is initialized first */
+	if (unlikely(!lowest_mask))
+		return -1;
+
+	if (task->nr_cpus_allowed == 1)
+		return -1; /* No other targets possible */
+
+	/*
+	 * If we're on asym system ensure we consider the different capacities
+	 * of the CPUs when searching for the lowest_mask.
+	 */
+	if (sched_asym_cpucap_active()) {
+
+		ret = cpupri_find_fitness(&task_rq(task)->rd->cpupri,
+					  task, lowest_mask,
+					  rt_task_fits_capacity);
+	} else {
+
+		ret = cpupri_find(&task_rq(task)->rd->cpupri,
+				  task, lowest_mask);
+	}
+
+	if (!ret)
+		return -1; /* No targets found */
+
+	/*
+	 * At this point we have built a mask of CPUs representing the
+	 * lowest priority tasks in the system.  Now we want to elect
+	 * the best one based on our affinity and topology.
+	 *
+	 * We prioritize the last CPU that the task executed on since
+	 * it is most likely cache-hot in that location.
+	 */
+	if (cpumask_test_cpu(cpu, lowest_mask))
+		return cpu;
+
+	/*
+	 * Otherwise, we consult the sched_domains span maps to figure
+	 * out which CPU is logically closest to our hot cache data.
+	 */
+	if (!cpumask_test_cpu(this_cpu, lowest_mask))
+		this_cpu = -1; /* Skip this_cpu opt if not among lowest */
+
+	rcu_read_lock();
+	for_each_domain(cpu, sd) {
+		if (sd->flags & SD_WAKE_AFFINE) {
+			int best_cpu;
+
+			/*
+			 * "this_cpu" is cheaper to preempt than a
+			 * remote processor.
+			 */
+			if (this_cpu != -1 &&
+			    cpumask_test_cpu(this_cpu, sched_domain_span(sd))) {
+				rcu_read_unlock();
+				return this_cpu;
+			}
+
+			best_cpu = cpumask_any_and_distribute(lowest_mask,
+							      sched_domain_span(sd));
+			if (best_cpu < nr_cpu_ids) {
+				rcu_read_unlock();
+				return best_cpu;
+			}
+		}
+	}
+	rcu_read_unlock();
+
+	/*
+	 * And finally, if there were no matches within the domains
+	 * just give the caller *something* to work with from the compatible
+	 * locations.
+	 */
+	if (this_cpu != -1)
+		return this_cpu;
+
+	cpu = cpumask_any_distribute(lowest_mask);
+	if (cpu < nr_cpu_ids)
+		return cpu;
+
+	return -1;
+}
+
+/* Will lock the rq it finds */
+static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
+{
+	struct rq *lowest_rq = NULL;
+	int tries;
+	int cpu;
+
+	for (tries = 0; tries < RT_MAX_TRIES; tries++) {
+		cpu = find_lowest_rq(task);
+
+		if ((cpu == -1) || (cpu == rq->cpu))
+			break;
+
+		lowest_rq = cpu_rq(cpu);
+
+		if (lowest_rq->rt.highest_prio.curr <= task->prio) {
+			/*
+			 * Target rq has tasks of equal or higher priority,
+			 * retrying does not release any lock and is unlikely
+			 * to yield a different result.
+			 */
+			lowest_rq = NULL;
+			break;
+		}
+
+		/* if the prio of this runqueue changed, try again */
+		if (double_lock_balance(rq, lowest_rq)) {
+			/*
+			 * We had to unlock the run queue. In
+			 * the mean time, task could have
+			 * migrated already or had its affinity changed.
+			 * Also make sure that it wasn't scheduled on its rq.
+			 * It is possible the task was scheduled, set
+			 * "migrate_disabled" and then got preempted, so we must
+			 * check the task migration disable flag here too.
+			 */
+			if (unlikely(task_rq(task) != rq ||
+				     !cpumask_test_cpu(lowest_rq->cpu, &task->cpus_mask) ||
+				     task_on_cpu(rq, task) ||
+				     !rt_task(task) ||
+				     is_migration_disabled(task) ||
+				     !task_on_rq_queued(task))) {
+
+				double_unlock_balance(rq, lowest_rq);
+				lowest_rq = NULL;
+				break;
+			}
+		}
+
+		/* If this rq is still suitable use it. */
+		if (lowest_rq->rt.highest_prio.curr > task->prio)
+			break;
+
+		/* try again */
+		double_unlock_balance(rq, lowest_rq);
+		lowest_rq = NULL;
+	}
+
+	return lowest_rq;
+}
+
+static struct task_struct *pick_next_pushable_task(struct rq *rq)
+{
+	struct task_struct *p;
+
+	if (!has_pushable_tasks(rq))
+		return NULL;
+
+	p = plist_first_entry(&rq->rt.pushable_tasks,
+			      struct task_struct, pushable_tasks);
+
+	BUG_ON(rq->cpu != task_cpu(p));
+	BUG_ON(task_current(rq, p));
+	BUG_ON(p->nr_cpus_allowed <= 1);
+
+	BUG_ON(!task_on_rq_queued(p));
+	BUG_ON(!rt_task(p));
+
+	return p;
+}
+
+/*
+ * If the current CPU has more than one RT task, see if the non
+ * running task can migrate over to a CPU that is running a task
+ * of lesser priority.
+ */
+static int push_rt_task(struct rq *rq, bool pull)
+{
+	struct task_struct *next_task;
+	struct rq *lowest_rq;
+	int ret = 0;
+
+	if (!rq->rt.overloaded)
+		return 0;
+
+	next_task = pick_next_pushable_task(rq);
+	if (!next_task)
+		return 0;
+
+retry:
+	/*
+	 * It's possible that the next_task slipped in of
+	 * higher priority than current. If that's the case
+	 * just reschedule current.
+	 */
+	if (unlikely(next_task->prio < rq->curr->prio)) {
+		resched_curr(rq);
+		return 0;
+	}
+
+	if (is_migration_disabled(next_task)) {
+		struct task_struct *push_task = NULL;
+		int cpu;
+
+		if (!pull || rq->push_busy)
+			return 0;
+
+		/*
+		 * Invoking find_lowest_rq() on anything but an RT task doesn't
+		 * make sense. Per the above priority check, curr has to
+		 * be of higher priority than next_task, so no need to
+		 * reschedule when bailing out.
+		 *
+		 * Note that the stoppers are masqueraded as SCHED_FIFO
+		 * (cf. sched_set_stop_task()), so we can't rely on rt_task().
+		 */
+		if (rq->curr->sched_class != &rt_sched_class)
+			return 0;
+
+		cpu = find_lowest_rq(rq->curr);
+		if (cpu == -1 || cpu == rq->cpu)
+			return 0;
+
+		/*
+		 * Given we found a CPU with lower priority than @next_task,
+		 * therefore it should be running. However we cannot migrate it
+		 * to this other CPU, instead attempt to push the current
+		 * running task on this CPU away.
+		 */
+		push_task = get_push_task(rq);
+		if (push_task) {
+			preempt_disable();
+			raw_spin_rq_unlock(rq);
+			stop_one_cpu_nowait(rq->cpu, push_cpu_stop,
+					    push_task, &rq->push_work);
+			preempt_enable();
+			raw_spin_rq_lock(rq);
+		}
+
+		return 0;
+	}
+
+	if (WARN_ON(next_task == rq->curr))
+		return 0;
+
+	/* We might release rq lock */
+	get_task_struct(next_task);
+
+	/* find_lock_lowest_rq locks the rq if found */
+	lowest_rq = find_lock_lowest_rq(next_task, rq);
+	if (!lowest_rq) {
+		struct task_struct *task;
+		/*
+		 * find_lock_lowest_rq releases rq->lock
+		 * so it is possible that next_task has migrated.
+		 *
+		 * We need to make sure that the task is still on the same
+		 * run-queue and is also still the next task eligible for
+		 * pushing.
+		 */
+		task = pick_next_pushable_task(rq);
+		if (task == next_task) {
+			/*
+			 * The task hasn't migrated, and is still the next
+			 * eligible task, but we failed to find a run-queue
+			 * to push it to.  Do not retry in this case, since
+			 * other CPUs will pull from us when ready.
+			 */
+			goto out;
+		}
+
+		if (!task)
+			/* No more tasks, just exit */
+			goto out;
+
+		/*
+		 * Something has shifted, try again.
+		 */
+		put_task_struct(next_task);
+		next_task = task;
+		goto retry;
+	}
+
+	deactivate_task(rq, next_task, 0);
+	set_task_cpu(next_task, lowest_rq->cpu);
+	activate_task(lowest_rq, next_task, 0);
+	resched_curr(lowest_rq);
+	ret = 1;
+
+	double_unlock_balance(rq, lowest_rq);
+out:
+	put_task_struct(next_task);
+
+	return ret;
+}
+
+static void push_rt_tasks(struct rq *rq)
+{
+	/* push_rt_task will return true if it moved an RT */
+	while (push_rt_task(rq, false))
+		;
+}
+
+#ifdef HAVE_RT_PUSH_IPI
+
+/*
+ * When a high priority task schedules out from a CPU and a lower priority
+ * task is scheduled in, a check is made to see if there's any RT tasks
+ * on other CPUs that are waiting to run because a higher priority RT task
+ * is currently running on its CPU. In this case, the CPU with multiple RT
+ * tasks queued on it (overloaded) needs to be notified that a CPU has opened
+ * up that may be able to run one of its non-running queued RT tasks.
+ *
+ * All CPUs with overloaded RT tasks need to be notified as there is currently
+ * no way to know which of these CPUs have the highest priority task waiting
+ * to run. Instead of trying to take a spinlock on each of these CPUs,
+ * which has shown to cause large latency when done on machines with many
+ * CPUs, sending an IPI to the CPUs to have them push off the overloaded
+ * RT tasks waiting to run.
+ *
+ * Just sending an IPI to each of the CPUs is also an issue, as on large
+ * count CPU machines, this can cause an IPI storm on a CPU, especially
+ * if its the only CPU with multiple RT tasks queued, and a large number
+ * of CPUs scheduling a lower priority task at the same time.
+ *
+ * Each root domain has its own irq work function that can iterate over
+ * all CPUs with RT overloaded tasks. Since all CPUs with overloaded RT
+ * task must be checked if there's one or many CPUs that are lowering
+ * their priority, there's a single irq work iterator that will try to
+ * push off RT tasks that are waiting to run.
+ *
+ * When a CPU schedules a lower priority task, it will kick off the
+ * irq work iterator that will jump to each CPU with overloaded RT tasks.
+ * As it only takes the first CPU that schedules a lower priority task
+ * to start the process, the rto_start variable is incremented and if
+ * the atomic result is one, then that CPU will try to take the rto_lock.
+ * This prevents high contention on the lock as the process handles all
+ * CPUs scheduling lower priority tasks.
+ *
+ * All CPUs that are scheduling a lower priority task will increment the
+ * rt_loop_next variable. This will make sure that the irq work iterator
+ * checks all RT overloaded CPUs whenever a CPU schedules a new lower
+ * priority task, even if the iterator is in the middle of a scan. Incrementing
+ * the rt_loop_next will cause the iterator to perform another scan.
+ *
+ */
+static int rto_next_cpu(struct root_domain *rd)
+{
+	int next;
+	int cpu;
+
+	/*
+	 * When starting the IPI RT pushing, the rto_cpu is set to -1,
+	 * rt_next_cpu() will simply return the first CPU found in
+	 * the rto_mask.
+	 *
+	 * If rto_next_cpu() is called with rto_cpu is a valid CPU, it
+	 * will return the next CPU found in the rto_mask.
+	 *
+	 * If there are no more CPUs left in the rto_mask, then a check is made
+	 * against rto_loop and rto_loop_next. rto_loop is only updated with
+	 * the rto_lock held, but any CPU may increment the rto_loop_next
+	 * without any locking.
+	 */
+	for (;;) {
+
+		/* When rto_cpu is -1 this acts like cpumask_first() */
+		cpu = cpumask_next(rd->rto_cpu, rd->rto_mask);
+
+		rd->rto_cpu = cpu;
+
+		if (cpu < nr_cpu_ids)
+			return cpu;
+
+		rd->rto_cpu = -1;
+
+		/*
+		 * ACQUIRE ensures we see the @rto_mask changes
+		 * made prior to the @next value observed.
+		 *
+		 * Matches WMB in rt_set_overload().
+		 */
+		next = atomic_read_acquire(&rd->rto_loop_next);
+
+		if (rd->rto_loop == next)
+			break;
+
+		rd->rto_loop = next;
+	}
+
+	return -1;
+}
+
+static inline bool rto_start_trylock(atomic_t *v)
+{
+	return !atomic_cmpxchg_acquire(v, 0, 1);
+}
+
+static inline void rto_start_unlock(atomic_t *v)
+{
+	atomic_set_release(v, 0);
+}
+
+static void tell_cpu_to_push(struct rq *rq)
+{
+	int cpu = -1;
+
+	/* Keep the loop going if the IPI is currently active */
+	atomic_inc(&rq->rd->rto_loop_next);
+
+	/* Only one CPU can initiate a loop at a time */
+	if (!rto_start_trylock(&rq->rd->rto_loop_start))
+		return;
+
+	raw_spin_lock(&rq->rd->rto_lock);
+
+	/*
+	 * The rto_cpu is updated under the lock, if it has a valid CPU
+	 * then the IPI is still running and will continue due to the
+	 * update to loop_next, and nothing needs to be done here.
+	 * Otherwise it is finishing up and an ipi needs to be sent.
+	 */
+	if (rq->rd->rto_cpu < 0)
+		cpu = rto_next_cpu(rq->rd);
+
+	raw_spin_unlock(&rq->rd->rto_lock);
+
+	rto_start_unlock(&rq->rd->rto_loop_start);
+
+	if (cpu >= 0) {
+		/* Make sure the rd does not get freed while pushing */
+		sched_get_rd(rq->rd);
+		irq_work_queue_on(&rq->rd->rto_push_work, cpu);
+	}
+}
+
+/* Called from hardirq context */
+void rto_push_irq_work_func(struct irq_work *work)
+{
+	struct root_domain *rd =
+		container_of(work, struct root_domain, rto_push_work);
+	struct rq *rq;
+	int cpu;
+
+	rq = this_rq();
+
+	/*
+	 * We do not need to grab the lock to check for has_pushable_tasks.
+	 * When it gets updated, a check is made if a push is possible.
+	 */
+	if (has_pushable_tasks(rq)) {
+		raw_spin_rq_lock(rq);
+		while (push_rt_task(rq, true))
+			;
+		raw_spin_rq_unlock(rq);
+	}
+
+	raw_spin_lock(&rd->rto_lock);
+
+	/* Pass the IPI to the next rt overloaded queue */
+	cpu = rto_next_cpu(rd);
+
+	raw_spin_unlock(&rd->rto_lock);
+
+	if (cpu < 0) {
+		sched_put_rd(rd);
+		return;
+	}
+
+	/* Try the next RT overloaded CPU */
+	irq_work_queue_on(&rd->rto_push_work, cpu);
+}
+#endif /* HAVE_RT_PUSH_IPI */
+
+static void pull_rt_task(struct rq *this_rq)
+{
+	int this_cpu = this_rq->cpu, cpu;
+	bool resched = false;
+	struct task_struct *p, *push_task;
+	struct rq *src_rq;
+	int rt_overload_count = rt_overloaded(this_rq);
+
+	if (likely(!rt_overload_count))
+		return;
+
+	/*
+	 * Match the barrier from rt_set_overloaded; this guarantees that if we
+	 * see overloaded we must also see the rto_mask bit.
+	 */
+	smp_rmb();
+
+	/* If we are the only overloaded CPU do nothing */
+	if (rt_overload_count == 1 &&
+	    cpumask_test_cpu(this_rq->cpu, this_rq->rd->rto_mask))
+		return;
+
+#ifdef HAVE_RT_PUSH_IPI
+	if (sched_feat(RT_PUSH_IPI)) {
+		tell_cpu_to_push(this_rq);
+		return;
+	}
+#endif
+
+	for_each_cpu(cpu, this_rq->rd->rto_mask) {
+		if (this_cpu == cpu)
+			continue;
+
+		src_rq = cpu_rq(cpu);
+
+		/*
+		 * Don't bother taking the src_rq->lock if the next highest
+		 * task is known to be lower-priority than our current task.
+		 * This may look racy, but if this value is about to go
+		 * logically higher, the src_rq will push this task away.
+		 * And if its going logically lower, we do not care
+		 */
+		if (src_rq->rt.highest_prio.next >=
+		    this_rq->rt.highest_prio.curr)
+			continue;
+
+		/*
+		 * We can potentially drop this_rq's lock in
+		 * double_lock_balance, and another CPU could
+		 * alter this_rq
+		 */
+		push_task = NULL;
+		double_lock_balance(this_rq, src_rq);
+
+		/*
+		 * We can pull only a task, which is pushable
+		 * on its rq, and no others.
+		 */
+		p = pick_highest_pushable_task(src_rq, this_cpu);
+
+		/*
+		 * Do we have an RT task that preempts
+		 * the to-be-scheduled task?
+		 */
+		if (p && (p->prio < this_rq->rt.highest_prio.curr)) {
+			WARN_ON(p == src_rq->curr);
+			WARN_ON(!task_on_rq_queued(p));
+
+			/*
+			 * There's a chance that p is higher in priority
+			 * than what's currently running on its CPU.
+			 * This is just that p is waking up and hasn't
+			 * had a chance to schedule. We only pull
+			 * p if it is lower in priority than the
+			 * current task on the run queue
+			 */
+			if (p->prio < src_rq->curr->prio)
+				goto skip;
+
+			if (is_migration_disabled(p)) {
+				push_task = get_push_task(src_rq);
+			} else {
+				deactivate_task(src_rq, p, 0);
+				set_task_cpu(p, this_cpu);
+				activate_task(this_rq, p, 0);
+				resched = true;
+			}
+			/*
+			 * We continue with the search, just in
+			 * case there's an even higher prio task
+			 * in another runqueue. (low likelihood
+			 * but possible)
+			 */
+		}
+skip:
+		double_unlock_balance(this_rq, src_rq);
+
+		if (push_task) {
+			preempt_disable();
+			raw_spin_rq_unlock(this_rq);
+			stop_one_cpu_nowait(src_rq->cpu, push_cpu_stop,
+					    push_task, &src_rq->push_work);
+			preempt_enable();
+			raw_spin_rq_lock(this_rq);
+		}
+	}
+
+	if (resched)
+		resched_curr(this_rq);
+}
+
+/*
+ * If we are not running and we are not going to reschedule soon, we should
+ * try to push tasks away now
+ */
+static void task_woken_rt(struct rq *rq, struct task_struct *p)
+{
+	bool need_to_push = !task_on_cpu(rq, p) &&
+			    !test_tsk_need_resched(rq->curr) &&
+			    p->nr_cpus_allowed > 1 &&
+			    (dl_task(rq->curr) || rt_task(rq->curr)) &&
+			    (rq->curr->nr_cpus_allowed < 2 ||
+			     rq->curr->prio <= p->prio);
+
+	if (need_to_push)
+		push_rt_tasks(rq);
+}
+
+/* Assumes rq->lock is held */
+static void rq_online_rt(struct rq *rq)
+{
+	if (rq->rt.overloaded)
+		rt_set_overload(rq);
+
+	__enable_runtime(rq);
+
+	cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio.curr);
+}
+
+/* Assumes rq->lock is held */
+static void rq_offline_rt(struct rq *rq)
+{
+	if (rq->rt.overloaded)
+		rt_clear_overload(rq);
+
+	__disable_runtime(rq);
+
+	cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_INVALID);
+}
+
+/*
+ * When switch from the rt queue, we bring ourselves to a position
+ * that we might want to pull RT tasks from other runqueues.
+ */
+static void switched_from_rt(struct rq *rq, struct task_struct *p)
+{
+	/*
+	 * If there are other RT tasks then we will reschedule
+	 * and the scheduling of the other RT tasks will handle
+	 * the balancing. But if we are the last RT task
+	 * we may need to handle the pulling of RT tasks
+	 * now.
+	 */
+	if (!task_on_rq_queued(p) || rq->rt.rt_nr_running)
+		return;
+
+	rt_queue_pull_task(rq);
+}
+
+void __init init_sched_rt_class(void)
+{
+	unsigned int i;
+
+	for_each_possible_cpu(i) {
+		zalloc_cpumask_var_node(&per_cpu(local_cpu_mask, i),
+					GFP_KERNEL, cpu_to_node(i));
+	}
+}
+#endif /* CONFIG_SMP */
+
+/*
+ * When switching a task to RT, we may overload the runqueue
+ * with RT tasks. In this case we try to push them off to
+ * other runqueues.
+ */
+static void switched_to_rt(struct rq *rq, struct task_struct *p)
+{
+	/*
+	 * If we are running, update the avg_rt tracking, as the running time
+	 * will now on be accounted into the latter.
+	 */
+	if (task_current(rq, p)) {
+		update_rt_rq_load_avg(rq_clock_pelt(rq), rq, 0);
+		return;
+	}
+
+	/*
+	 * If we are not running we may need to preempt the current
+	 * running task. If that current running task is also an RT task
+	 * then see if we can move to another run queue.
+	 */
+	if (task_on_rq_queued(p)) {
+#ifdef CONFIG_SMP
+		if (p->nr_cpus_allowed > 1 && rq->rt.overloaded)
+			rt_queue_push_tasks(rq);
+#endif /* CONFIG_SMP */
+		if (p->prio < rq->curr->prio && cpu_online(cpu_of(rq)))
+			resched_curr(rq);
+	}
+}
+
+/*
+ * Priority of the task has changed. This may cause
+ * us to initiate a push or pull.
+ */
+static void
+prio_changed_rt(struct rq *rq, struct task_struct *p, int oldprio)
+{
+	if (!task_on_rq_queued(p))
+		return;
+
+	if (task_current(rq, p)) {
+#ifdef CONFIG_SMP
+		/*
+		 * If our priority decreases while running, we
+		 * may need to pull tasks to this runqueue.
+		 */
+		if (oldprio < p->prio)
+			rt_queue_pull_task(rq);
+
+		/*
+		 * If there's a higher priority task waiting to run
+		 * then reschedule.
+		 */
+		if (p->prio > rq->rt.highest_prio.curr)
+			resched_curr(rq);
+#else
+		/* For UP simply resched on drop of prio */
+		if (oldprio < p->prio)
+			resched_curr(rq);
+#endif /* CONFIG_SMP */
+	} else {
+		/*
+		 * This task is not running, but if it is
+		 * greater than the current running task
+		 * then reschedule.
+		 */
+		if (p->prio < rq->curr->prio)
+			resched_curr(rq);
+	}
+}
+
+#ifdef CONFIG_POSIX_TIMERS
+static void watchdog(struct rq *rq, struct task_struct *p)
+{
+	unsigned long soft, hard;
+
+	/* max may change after cur was read, this will be fixed next tick */
+	soft = task_rlimit(p, RLIMIT_RTTIME);
+	hard = task_rlimit_max(p, RLIMIT_RTTIME);
+
+	if (soft != RLIM_INFINITY) {
+		unsigned long next;
+
+		if (p->rt.watchdog_stamp != jiffies) {
+			p->rt.timeout++;
+			p->rt.watchdog_stamp = jiffies;
+		}
+
+		next = DIV_ROUND_UP(min(soft, hard), USEC_PER_SEC/HZ);
+		if (p->rt.timeout > next) {
+			posix_cputimers_rt_watchdog(&p->posix_cputimers,
+						    p->se.sum_exec_runtime);
+		}
+	}
+}
+#else
+static inline void watchdog(struct rq *rq, struct task_struct *p) { }
+#endif
+
+/*
+ * scheduler tick hitting a task of our scheduling class.
+ *
+ * NOTE: This function can be called remotely by the tick offload that
+ * goes along full dynticks. Therefore no local assumption can be made
+ * and everything must be accessed through the @rq and @curr passed in
+ * parameters.
+ */
+static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
+{
+	struct sched_rt_entity *rt_se = &p->rt;
+
+	update_curr_rt(rq);
+	update_rt_rq_load_avg(rq_clock_pelt(rq), rq, 1);
+
+	watchdog(rq, p);
+
+	/*
+	 * RR tasks need a special form of timeslice management.
+	 * FIFO tasks have no timeslices.
+	 */
+	if (p->policy != SCHED_RR)
+		return;
+
+	if (--p->rt.time_slice)
+		return;
+
+	p->rt.time_slice = sched_rr_timeslice;
+
+	/*
+	 * Requeue to the end of queue if we (and all of our ancestors) are not
+	 * the only element on the queue
+	 */
+	for_each_sched_rt_entity(rt_se) {
+		if (rt_se->run_list.prev != rt_se->run_list.next) {
+			requeue_task_rt(rq, p, 0);
+			resched_curr(rq);
+			return;
+		}
+	}
+}
+
+static unsigned int get_rr_interval_rt(struct rq *rq, struct task_struct *task)
+{
+	/*
+	 * Time slice is 0 for SCHED_FIFO tasks
+	 */
+	if (task->policy == SCHED_RR)
+		return sched_rr_timeslice;
+	else
+		return 0;
+}
+
+#ifdef CONFIG_SCHED_CORE
+static int task_is_throttled_rt(struct task_struct *p, int cpu)
+{
+	struct rt_rq *rt_rq;
+
+#ifdef CONFIG_RT_GROUP_SCHED
+	rt_rq = task_group(p)->rt_rq[cpu];
+#else
+	rt_rq = &cpu_rq(cpu)->rt;
+#endif
+
+	return rt_rq_throttled(rt_rq);
+}
+#endif
+
+DEFINE_SCHED_CLASS(rt) = {
+
+	.enqueue_task		= enqueue_task_rt,
+	.dequeue_task		= dequeue_task_rt,
+	.yield_task		= yield_task_rt,
+
+	.check_preempt_curr	= check_preempt_curr_rt,
+
+	.pick_next_task		= pick_next_task_rt,
+	.put_prev_task		= put_prev_task_rt,
+	.set_next_task          = set_next_task_rt,
+
+#ifdef CONFIG_SMP
+	.balance		= balance_rt,
+	.pick_task		= pick_task_rt,
+	.select_task_rq		= select_task_rq_rt,
+	.set_cpus_allowed       = set_cpus_allowed_common,
+	.rq_online              = rq_online_rt,
+	.rq_offline             = rq_offline_rt,
+	.task_woken		= task_woken_rt,
+	.switched_from		= switched_from_rt,
+	.find_lock_rq		= find_lock_lowest_rq,
+#endif
+
+	.task_tick		= task_tick_rt,
+
+	.get_rr_interval	= get_rr_interval_rt,
+
+	.prio_changed		= prio_changed_rt,
+	.switched_to		= switched_to_rt,
+
+	.update_curr		= update_curr_rt,
+
+#ifdef CONFIG_SCHED_CORE
+	.task_is_throttled	= task_is_throttled_rt,
+#endif
+
+#ifdef CONFIG_UCLAMP_TASK
+	.uclamp_enabled		= 1,
+#endif
+};
+
+#ifdef CONFIG_RT_GROUP_SCHED
+/*
+ * Ensure that the real time constraints are schedulable.
+ */
+static DEFINE_MUTEX(rt_constraints_mutex);
+
+static inline int tg_has_rt_tasks(struct task_group *tg)
+{
+	struct task_struct *task;
+	struct css_task_iter it;
+	int ret = 0;
+
+	/*
+	 * Autogroups do not have RT tasks; see autogroup_create().
+	 */
+	if (task_group_is_autogroup(tg))
+		return 0;
+
+	css_task_iter_start(&tg->css, 0, &it);
+	while (!ret && (task = css_task_iter_next(&it)))
+		ret |= rt_task(task);
+	css_task_iter_end(&it);
+
+	return ret;
+}
+
+struct rt_schedulable_data {
+	struct task_group *tg;
+	u64 rt_period;
+	u64 rt_runtime;
+};
+
+static int tg_rt_schedulable(struct task_group *tg, void *data)
+{
+	struct rt_schedulable_data *d = data;
+	struct task_group *child;
+	unsigned long total, sum = 0;
+	u64 period, runtime;
+
+	period = ktime_to_ns(tg->rt_bandwidth.rt_period);
+	runtime = tg->rt_bandwidth.rt_runtime;
+
+	if (tg == d->tg) {
+		period = d->rt_period;
+		runtime = d->rt_runtime;
+	}
+
+	/*
+	 * Cannot have more runtime than the period.
+	 */
+	if (runtime > period && runtime != RUNTIME_INF)
+		return -EINVAL;
+
+	/*
+	 * Ensure we don't starve existing RT tasks if runtime turns zero.
+	 */
+	if (rt_bandwidth_enabled() && !runtime &&
+	    tg->rt_bandwidth.rt_runtime && tg_has_rt_tasks(tg))
+		return -EBUSY;
+
+	total = to_ratio(period, runtime);
+
+	/*
+	 * Nobody can have more than the global setting allows.
+	 */
+	if (total > to_ratio(global_rt_period(), global_rt_runtime()))
+		return -EINVAL;
+
+	/*
+	 * The sum of our children's runtime should not exceed our own.
+	 */
+	list_for_each_entry_rcu(child, &tg->children, siblings) {
+		period = ktime_to_ns(child->rt_bandwidth.rt_period);
+		runtime = child->rt_bandwidth.rt_runtime;
+
+		if (child == d->tg) {
+			period = d->rt_period;
+			runtime = d->rt_runtime;
+		}
+
+		sum += to_ratio(period, runtime);
+	}
+
+	if (sum > total)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
+{
+	int ret;
+
+	struct rt_schedulable_data data = {
+		.tg = tg,
+		.rt_period = period,
+		.rt_runtime = runtime,
+	};
+
+	rcu_read_lock();
+	ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data);
+	rcu_read_unlock();
+
+	return ret;
+}
+
+static int tg_set_rt_bandwidth(struct task_group *tg,
+		u64 rt_period, u64 rt_runtime)
+{
+	int i, err = 0;
+
+	/*
+	 * Disallowing the root group RT runtime is BAD, it would disallow the
+	 * kernel creating (and or operating) RT threads.
+	 */
+	if (tg == &root_task_group && rt_runtime == 0)
+		return -EINVAL;
+
+	/* No period doesn't make any sense. */
+	if (rt_period == 0)
+		return -EINVAL;
+
+	/*
+	 * Bound quota to defend quota against overflow during bandwidth shift.
+	 */
+	if (rt_runtime != RUNTIME_INF && rt_runtime > max_rt_runtime)
+		return -EINVAL;
+
+	mutex_lock(&rt_constraints_mutex);
+	err = __rt_schedulable(tg, rt_period, rt_runtime);
+	if (err)
+		goto unlock;
+
+	raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
+	tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
+	tg->rt_bandwidth.rt_runtime = rt_runtime;
+
+	for_each_possible_cpu(i) {
+		struct rt_rq *rt_rq = tg->rt_rq[i];
+
+		raw_spin_lock(&rt_rq->rt_runtime_lock);
+		rt_rq->rt_runtime = rt_runtime;
+		raw_spin_unlock(&rt_rq->rt_runtime_lock);
+	}
+	raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
+unlock:
+	mutex_unlock(&rt_constraints_mutex);
+
+	return err;
+}
+
+int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
+{
+	u64 rt_runtime, rt_period;
+
+	rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
+	rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
+	if (rt_runtime_us < 0)
+		rt_runtime = RUNTIME_INF;
+	else if ((u64)rt_runtime_us > U64_MAX / NSEC_PER_USEC)
+		return -EINVAL;
+
+	return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
+}
+
+long sched_group_rt_runtime(struct task_group *tg)
+{
+	u64 rt_runtime_us;
+
+	if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
+		return -1;
+
+	rt_runtime_us = tg->rt_bandwidth.rt_runtime;
+	do_div(rt_runtime_us, NSEC_PER_USEC);
+	return rt_runtime_us;
+}
+
+int sched_group_set_rt_period(struct task_group *tg, u64 rt_period_us)
+{
+	u64 rt_runtime, rt_period;
+
+	if (rt_period_us > U64_MAX / NSEC_PER_USEC)
+		return -EINVAL;
+
+	rt_period = rt_period_us * NSEC_PER_USEC;
+	rt_runtime = tg->rt_bandwidth.rt_runtime;
+
+	return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
+}
+
+long sched_group_rt_period(struct task_group *tg)
+{
+	u64 rt_period_us;
+
+	rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
+	do_div(rt_period_us, NSEC_PER_USEC);
+	return rt_period_us;
+}
+
+#ifdef CONFIG_SYSCTL
+static int sched_rt_global_constraints(void)
+{
+	int ret = 0;
+
+	mutex_lock(&rt_constraints_mutex);
+	ret = __rt_schedulable(NULL, 0, 0);
+	mutex_unlock(&rt_constraints_mutex);
+
+	return ret;
+}
+#endif /* CONFIG_SYSCTL */
+
+int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
+{
+	/* Don't accept realtime tasks when there is no way for them to run */
+	if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0)
+		return 0;
+
+	return 1;
+}
+
+#else /* !CONFIG_RT_GROUP_SCHED */
+
+#ifdef CONFIG_SYSCTL
+static int sched_rt_global_constraints(void)
+{
+	unsigned long flags;
+	int i;
+
+	raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
+	for_each_possible_cpu(i) {
+		struct rt_rq *rt_rq = &cpu_rq(i)->rt;
+
+		raw_spin_lock(&rt_rq->rt_runtime_lock);
+		rt_rq->rt_runtime = global_rt_runtime();
+		raw_spin_unlock(&rt_rq->rt_runtime_lock);
+	}
+	raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
+
+	return 0;
+}
+#endif /* CONFIG_SYSCTL */
+#endif /* CONFIG_RT_GROUP_SCHED */
+
+#ifdef CONFIG_SYSCTL
+static int sched_rt_global_validate(void)
+{
+	if (sysctl_sched_rt_period <= 0)
+		return -EINVAL;
+
+	if ((sysctl_sched_rt_runtime != RUNTIME_INF) &&
+		((sysctl_sched_rt_runtime > sysctl_sched_rt_period) ||
+		 ((u64)sysctl_sched_rt_runtime *
+			NSEC_PER_USEC > max_rt_runtime)))
+		return -EINVAL;
+
+	return 0;
+}
+
+static void sched_rt_do_global(void)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
+	def_rt_bandwidth.rt_runtime = global_rt_runtime();
+	def_rt_bandwidth.rt_period = ns_to_ktime(global_rt_period());
+	raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
+}
+
+static int sched_rt_handler(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
+{
+	int old_period, old_runtime;
+	static DEFINE_MUTEX(mutex);
+	int ret;
+
+	mutex_lock(&mutex);
+	old_period = sysctl_sched_rt_period;
+	old_runtime = sysctl_sched_rt_runtime;
+
+	ret = proc_dointvec(table, write, buffer, lenp, ppos);
+
+	if (!ret && write) {
+		ret = sched_rt_global_validate();
+		if (ret)
+			goto undo;
+
+		ret = sched_dl_global_validate();
+		if (ret)
+			goto undo;
+
+		ret = sched_rt_global_constraints();
+		if (ret)
+			goto undo;
+
+		sched_rt_do_global();
+		sched_dl_do_global();
+	}
+	if (0) {
+undo:
+		sysctl_sched_rt_period = old_period;
+		sysctl_sched_rt_runtime = old_runtime;
+	}
+	mutex_unlock(&mutex);
+
+	return ret;
+}
+
+static int sched_rr_handler(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
+{
+	int ret;
+	static DEFINE_MUTEX(mutex);
+
+	mutex_lock(&mutex);
+	ret = proc_dointvec(table, write, buffer, lenp, ppos);
+	/*
+	 * Make sure that internally we keep jiffies.
+	 * Also, writing zero resets the timeslice to default:
+	 */
+	if (!ret && write) {
+		sched_rr_timeslice =
+			sysctl_sched_rr_timeslice <= 0 ? RR_TIMESLICE :
+			msecs_to_jiffies(sysctl_sched_rr_timeslice);
+
+		if (sysctl_sched_rr_timeslice <= 0)
+			sysctl_sched_rr_timeslice = jiffies_to_msecs(RR_TIMESLICE);
+	}
+	mutex_unlock(&mutex);
+
+	return ret;
+}
+#endif /* CONFIG_SYSCTL */
+
+#ifdef CONFIG_SCHED_DEBUG
+void print_rt_stats(struct seq_file *m, int cpu)
+{
+	rt_rq_iter_t iter;
+	struct rt_rq *rt_rq;
+
+	rcu_read_lock();
+	for_each_rt_rq(rt_rq, iter, cpu_rq(cpu))
+		print_rt_rq(m, cpu, rt_rq);
+	rcu_read_unlock();
+}
+#endif /* CONFIG_SCHED_DEBUG */
diff --git a/kernel/sched/sched-pelt.h b/kernel/sched/sched-pelt.h
new file mode 100644
index 0000000000..c529706bed
--- /dev/null
+++ b/kernel/sched/sched-pelt.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Generated by Documentation/scheduler/sched-pelt; do not modify. */
+
+static const u32 runnable_avg_yN_inv[] __maybe_unused = {
+	0xffffffff, 0xfa83b2da, 0xf5257d14, 0xefe4b99a, 0xeac0c6e6, 0xe5b906e6,
+	0xe0ccdeeb, 0xdbfbb796, 0xd744fcc9, 0xd2a81d91, 0xce248c14, 0xc9b9bd85,
+	0xc5672a10, 0xc12c4cc9, 0xbd08a39e, 0xb8fbaf46, 0xb504f333, 0xb123f581,
+	0xad583ee9, 0xa9a15ab4, 0xa5fed6a9, 0xa2704302, 0x9ef5325f, 0x9b8d39b9,
+	0x9837f050, 0x94f4efa8, 0x91c3d373, 0x8ea4398a, 0x8b95c1e3, 0x88980e80,
+	0x85aac367, 0x82cd8698,
+};
+
+#define LOAD_AVG_PERIOD 32
+#define LOAD_AVG_MAX 47742
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
new file mode 100644
index 0000000000..0484627240
--- /dev/null
+++ b/kernel/sched/sched.h
@@ -0,0 +1,3531 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Scheduler internal types and methods:
+ */
+#ifndef _KERNEL_SCHED_SCHED_H
+#define _KERNEL_SCHED_SCHED_H
+
+#include <linux/sched/affinity.h>
+#include <linux/sched/autogroup.h>
+#include <linux/sched/cpufreq.h>
+#include <linux/sched/deadline.h>
+#include <linux/sched.h>
+#include <linux/sched/loadavg.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/rseq_api.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/smt.h>
+#include <linux/sched/stat.h>
+#include <linux/sched/sysctl.h>
+#include <linux/sched/task_flags.h>
+#include <linux/sched/task.h>
+#include <linux/sched/topology.h>
+
+#include <linux/atomic.h>
+#include <linux/bitmap.h>
+#include <linux/bug.h>
+#include <linux/capability.h>
+#include <linux/cgroup_api.h>
+#include <linux/cgroup.h>
+#include <linux/context_tracking.h>
+#include <linux/cpufreq.h>
+#include <linux/cpumask_api.h>
+#include <linux/ctype.h>
+#include <linux/file.h>
+#include <linux/fs_api.h>
+#include <linux/hrtimer_api.h>
+#include <linux/interrupt.h>
+#include <linux/irq_work.h>
+#include <linux/jiffies.h>
+#include <linux/kref_api.h>
+#include <linux/kthread.h>
+#include <linux/ktime_api.h>
+#include <linux/lockdep_api.h>
+#include <linux/lockdep.h>
+#include <linux/minmax.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/mutex_api.h>
+#include <linux/plist.h>
+#include <linux/poll.h>
+#include <linux/proc_fs.h>
+#include <linux/profile.h>
+#include <linux/psi.h>
+#include <linux/rcupdate.h>
+#include <linux/seq_file.h>
+#include <linux/seqlock.h>
+#include <linux/softirq.h>
+#include <linux/spinlock_api.h>
+#include <linux/static_key.h>
+#include <linux/stop_machine.h>
+#include <linux/syscalls_api.h>
+#include <linux/syscalls.h>
+#include <linux/tick.h>
+#include <linux/topology.h>
+#include <linux/types.h>
+#include <linux/u64_stats_sync_api.h>
+#include <linux/uaccess.h>
+#include <linux/wait_api.h>
+#include <linux/wait_bit.h>
+#include <linux/workqueue_api.h>
+
+#include <trace/events/power.h>
+#include <trace/events/sched.h>
+
+#include "../workqueue_internal.h"
+
+#ifdef CONFIG_CGROUP_SCHED
+#include <linux/cgroup.h>
+#include <linux/psi.h>
+#endif
+
+#ifdef CONFIG_SCHED_DEBUG
+# include <linux/static_key.h>
+#endif
+
+#ifdef CONFIG_PARAVIRT
+# include <asm/paravirt.h>
+# include <asm/paravirt_api_clock.h>
+#endif
+
+#include "cpupri.h"
+#include "cpudeadline.h"
+
+#ifdef CONFIG_SCHED_DEBUG
+# define SCHED_WARN_ON(x)      WARN_ONCE(x, #x)
+#else
+# define SCHED_WARN_ON(x)      ({ (void)(x), 0; })
+#endif
+
+struct rq;
+struct cpuidle_state;
+
+/* task_struct::on_rq states: */
+#define TASK_ON_RQ_QUEUED	1
+#define TASK_ON_RQ_MIGRATING	2
+
+extern __read_mostly int scheduler_running;
+
+extern unsigned long calc_load_update;
+extern atomic_long_t calc_load_tasks;
+
+extern unsigned int sysctl_sched_child_runs_first;
+
+extern void calc_global_load_tick(struct rq *this_rq);
+extern long calc_load_fold_active(struct rq *this_rq, long adjust);
+
+extern void call_trace_sched_update_nr_running(struct rq *rq, int count);
+
+extern unsigned int sysctl_sched_rt_period;
+extern int sysctl_sched_rt_runtime;
+extern int sched_rr_timeslice;
+
+/*
+ * Helpers for converting nanosecond timing to jiffy resolution
+ */
+#define NS_TO_JIFFIES(TIME)	((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
+
+/*
+ * Increase resolution of nice-level calculations for 64-bit architectures.
+ * The extra resolution improves shares distribution and load balancing of
+ * low-weight task groups (eg. nice +19 on an autogroup), deeper taskgroup
+ * hierarchies, especially on larger systems. This is not a user-visible change
+ * and does not change the user-interface for setting shares/weights.
+ *
+ * We increase resolution only if we have enough bits to allow this increased
+ * resolution (i.e. 64-bit). The costs for increasing resolution when 32-bit
+ * are pretty high and the returns do not justify the increased costs.
+ *
+ * Really only required when CONFIG_FAIR_GROUP_SCHED=y is also set, but to
+ * increase coverage and consistency always enable it on 64-bit platforms.
+ */
+#ifdef CONFIG_64BIT
+# define NICE_0_LOAD_SHIFT	(SCHED_FIXEDPOINT_SHIFT + SCHED_FIXEDPOINT_SHIFT)
+# define scale_load(w)		((w) << SCHED_FIXEDPOINT_SHIFT)
+# define scale_load_down(w) \
+({ \
+	unsigned long __w = (w); \
+	if (__w) \
+		__w = max(2UL, __w >> SCHED_FIXEDPOINT_SHIFT); \
+	__w; \
+})
+#else
+# define NICE_0_LOAD_SHIFT	(SCHED_FIXEDPOINT_SHIFT)
+# define scale_load(w)		(w)
+# define scale_load_down(w)	(w)
+#endif
+
+/*
+ * Task weight (visible to users) and its load (invisible to users) have
+ * independent resolution, but they should be well calibrated. We use
+ * scale_load() and scale_load_down(w) to convert between them. The
+ * following must be true:
+ *
+ *  scale_load(sched_prio_to_weight[NICE_TO_PRIO(0)-MAX_RT_PRIO]) == NICE_0_LOAD
+ *
+ */
+#define NICE_0_LOAD		(1L << NICE_0_LOAD_SHIFT)
+
+/*
+ * Single value that decides SCHED_DEADLINE internal math precision.
+ * 10 -> just above 1us
+ * 9  -> just above 0.5us
+ */
+#define DL_SCALE		10
+
+/*
+ * Single value that denotes runtime == period, ie unlimited time.
+ */
+#define RUNTIME_INF		((u64)~0ULL)
+
+static inline int idle_policy(int policy)
+{
+	return policy == SCHED_IDLE;
+}
+static inline int fair_policy(int policy)
+{
+	return policy == SCHED_NORMAL || policy == SCHED_BATCH;
+}
+
+static inline int rt_policy(int policy)
+{
+	return policy == SCHED_FIFO || policy == SCHED_RR;
+}
+
+static inline int dl_policy(int policy)
+{
+	return policy == SCHED_DEADLINE;
+}
+static inline bool valid_policy(int policy)
+{
+	return idle_policy(policy) || fair_policy(policy) ||
+		rt_policy(policy) || dl_policy(policy);
+}
+
+static inline int task_has_idle_policy(struct task_struct *p)
+{
+	return idle_policy(p->policy);
+}
+
+static inline int task_has_rt_policy(struct task_struct *p)
+{
+	return rt_policy(p->policy);
+}
+
+static inline int task_has_dl_policy(struct task_struct *p)
+{
+	return dl_policy(p->policy);
+}
+
+#define cap_scale(v, s) ((v)*(s) >> SCHED_CAPACITY_SHIFT)
+
+static inline void update_avg(u64 *avg, u64 sample)
+{
+	s64 diff = sample - *avg;
+	*avg += diff / 8;
+}
+
+/*
+ * Shifting a value by an exponent greater *or equal* to the size of said value
+ * is UB; cap at size-1.
+ */
+#define shr_bound(val, shift)							\
+	(val >> min_t(typeof(shift), shift, BITS_PER_TYPE(typeof(val)) - 1))
+
+/*
+ * !! For sched_setattr_nocheck() (kernel) only !!
+ *
+ * This is actually gross. :(
+ *
+ * It is used to make schedutil kworker(s) higher priority than SCHED_DEADLINE
+ * tasks, but still be able to sleep. We need this on platforms that cannot
+ * atomically change clock frequency. Remove once fast switching will be
+ * available on such platforms.
+ *
+ * SUGOV stands for SchedUtil GOVernor.
+ */
+#define SCHED_FLAG_SUGOV	0x10000000
+
+#define SCHED_DL_FLAGS (SCHED_FLAG_RECLAIM | SCHED_FLAG_DL_OVERRUN | SCHED_FLAG_SUGOV)
+
+static inline bool dl_entity_is_special(const struct sched_dl_entity *dl_se)
+{
+#ifdef CONFIG_CPU_FREQ_GOV_SCHEDUTIL
+	return unlikely(dl_se->flags & SCHED_FLAG_SUGOV);
+#else
+	return false;
+#endif
+}
+
+/*
+ * Tells if entity @a should preempt entity @b.
+ */
+static inline bool dl_entity_preempt(const struct sched_dl_entity *a,
+				     const struct sched_dl_entity *b)
+{
+	return dl_entity_is_special(a) ||
+	       dl_time_before(a->deadline, b->deadline);
+}
+
+/*
+ * This is the priority-queue data structure of the RT scheduling class:
+ */
+struct rt_prio_array {
+	DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */
+	struct list_head queue[MAX_RT_PRIO];
+};
+
+struct rt_bandwidth {
+	/* nests inside the rq lock: */
+	raw_spinlock_t		rt_runtime_lock;
+	ktime_t			rt_period;
+	u64			rt_runtime;
+	struct hrtimer		rt_period_timer;
+	unsigned int		rt_period_active;
+};
+
+void __dl_clear_params(struct task_struct *p);
+
+static inline int dl_bandwidth_enabled(void)
+{
+	return sysctl_sched_rt_runtime >= 0;
+}
+
+/*
+ * To keep the bandwidth of -deadline tasks under control
+ * we need some place where:
+ *  - store the maximum -deadline bandwidth of each cpu;
+ *  - cache the fraction of bandwidth that is currently allocated in
+ *    each root domain;
+ *
+ * This is all done in the data structure below. It is similar to the
+ * one used for RT-throttling (rt_bandwidth), with the main difference
+ * that, since here we are only interested in admission control, we
+ * do not decrease any runtime while the group "executes", neither we
+ * need a timer to replenish it.
+ *
+ * With respect to SMP, bandwidth is given on a per root domain basis,
+ * meaning that:
+ *  - bw (< 100%) is the deadline bandwidth of each CPU;
+ *  - total_bw is the currently allocated bandwidth in each root domain;
+ */
+struct dl_bw {
+	raw_spinlock_t		lock;
+	u64			bw;
+	u64			total_bw;
+};
+
+extern void init_dl_bw(struct dl_bw *dl_b);
+extern int  sched_dl_global_validate(void);
+extern void sched_dl_do_global(void);
+extern int  sched_dl_overflow(struct task_struct *p, int policy, const struct sched_attr *attr);
+extern void __setparam_dl(struct task_struct *p, const struct sched_attr *attr);
+extern void __getparam_dl(struct task_struct *p, struct sched_attr *attr);
+extern bool __checkparam_dl(const struct sched_attr *attr);
+extern bool dl_param_changed(struct task_struct *p, const struct sched_attr *attr);
+extern int  dl_cpuset_cpumask_can_shrink(const struct cpumask *cur, const struct cpumask *trial);
+extern int  dl_bw_check_overflow(int cpu);
+
+#ifdef CONFIG_CGROUP_SCHED
+
+struct cfs_rq;
+struct rt_rq;
+
+extern struct list_head task_groups;
+
+struct cfs_bandwidth {
+#ifdef CONFIG_CFS_BANDWIDTH
+	raw_spinlock_t		lock;
+	ktime_t			period;
+	u64			quota;
+	u64			runtime;
+	u64			burst;
+	u64			runtime_snap;
+	s64			hierarchical_quota;
+
+	u8			idle;
+	u8			period_active;
+	u8			slack_started;
+	struct hrtimer		period_timer;
+	struct hrtimer		slack_timer;
+	struct list_head	throttled_cfs_rq;
+
+	/* Statistics: */
+	int			nr_periods;
+	int			nr_throttled;
+	int			nr_burst;
+	u64			throttled_time;
+	u64			burst_time;
+#endif
+};
+
+/* Task group related information */
+struct task_group {
+	struct cgroup_subsys_state css;
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	/* schedulable entities of this group on each CPU */
+	struct sched_entity	**se;
+	/* runqueue "owned" by this group on each CPU */
+	struct cfs_rq		**cfs_rq;
+	unsigned long		shares;
+
+	/* A positive value indicates that this is a SCHED_IDLE group. */
+	int			idle;
+
+#ifdef	CONFIG_SMP
+	/*
+	 * load_avg can be heavily contended at clock tick time, so put
+	 * it in its own cacheline separated from the fields above which
+	 * will also be accessed at each tick.
+	 */
+	atomic_long_t		load_avg ____cacheline_aligned;
+#endif
+#endif
+
+#ifdef CONFIG_RT_GROUP_SCHED
+	struct sched_rt_entity	**rt_se;
+	struct rt_rq		**rt_rq;
+
+	struct rt_bandwidth	rt_bandwidth;
+#endif
+
+	struct rcu_head		rcu;
+	struct list_head	list;
+
+	struct task_group	*parent;
+	struct list_head	siblings;
+	struct list_head	children;
+
+#ifdef CONFIG_SCHED_AUTOGROUP
+	struct autogroup	*autogroup;
+#endif
+
+	struct cfs_bandwidth	cfs_bandwidth;
+
+#ifdef CONFIG_UCLAMP_TASK_GROUP
+	/* The two decimal precision [%] value requested from user-space */
+	unsigned int		uclamp_pct[UCLAMP_CNT];
+	/* Clamp values requested for a task group */
+	struct uclamp_se	uclamp_req[UCLAMP_CNT];
+	/* Effective clamp values used for a task group */
+	struct uclamp_se	uclamp[UCLAMP_CNT];
+#endif
+
+};
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+#define ROOT_TASK_GROUP_LOAD	NICE_0_LOAD
+
+/*
+ * A weight of 0 or 1 can cause arithmetics problems.
+ * A weight of a cfs_rq is the sum of weights of which entities
+ * are queued on this cfs_rq, so a weight of a entity should not be
+ * too large, so as the shares value of a task group.
+ * (The default weight is 1024 - so there's no practical
+ *  limitation from this.)
+ */
+#define MIN_SHARES		(1UL <<  1)
+#define MAX_SHARES		(1UL << 18)
+#endif
+
+typedef int (*tg_visitor)(struct task_group *, void *);
+
+extern int walk_tg_tree_from(struct task_group *from,
+			     tg_visitor down, tg_visitor up, void *data);
+
+/*
+ * Iterate the full tree, calling @down when first entering a node and @up when
+ * leaving it for the final time.
+ *
+ * Caller must hold rcu_lock or sufficient equivalent.
+ */
+static inline int walk_tg_tree(tg_visitor down, tg_visitor up, void *data)
+{
+	return walk_tg_tree_from(&root_task_group, down, up, data);
+}
+
+extern int tg_nop(struct task_group *tg, void *data);
+
+extern void free_fair_sched_group(struct task_group *tg);
+extern int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent);
+extern void online_fair_sched_group(struct task_group *tg);
+extern void unregister_fair_sched_group(struct task_group *tg);
+extern void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
+			struct sched_entity *se, int cpu,
+			struct sched_entity *parent);
+extern void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b, struct cfs_bandwidth *parent);
+
+extern void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b);
+extern void start_cfs_bandwidth(struct cfs_bandwidth *cfs_b);
+extern void unthrottle_cfs_rq(struct cfs_rq *cfs_rq);
+extern bool cfs_task_bw_constrained(struct task_struct *p);
+
+extern void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
+		struct sched_rt_entity *rt_se, int cpu,
+		struct sched_rt_entity *parent);
+extern int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us);
+extern int sched_group_set_rt_period(struct task_group *tg, u64 rt_period_us);
+extern long sched_group_rt_runtime(struct task_group *tg);
+extern long sched_group_rt_period(struct task_group *tg);
+extern int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk);
+
+extern struct task_group *sched_create_group(struct task_group *parent);
+extern void sched_online_group(struct task_group *tg,
+			       struct task_group *parent);
+extern void sched_destroy_group(struct task_group *tg);
+extern void sched_release_group(struct task_group *tg);
+
+extern void sched_move_task(struct task_struct *tsk);
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+extern int sched_group_set_shares(struct task_group *tg, unsigned long shares);
+
+extern int sched_group_set_idle(struct task_group *tg, long idle);
+
+#ifdef CONFIG_SMP
+extern void set_task_rq_fair(struct sched_entity *se,
+			     struct cfs_rq *prev, struct cfs_rq *next);
+#else /* !CONFIG_SMP */
+static inline void set_task_rq_fair(struct sched_entity *se,
+			     struct cfs_rq *prev, struct cfs_rq *next) { }
+#endif /* CONFIG_SMP */
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+#else /* CONFIG_CGROUP_SCHED */
+
+struct cfs_bandwidth { };
+static inline bool cfs_task_bw_constrained(struct task_struct *p) { return false; }
+
+#endif	/* CONFIG_CGROUP_SCHED */
+
+extern void unregister_rt_sched_group(struct task_group *tg);
+extern void free_rt_sched_group(struct task_group *tg);
+extern int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent);
+
+/*
+ * u64_u32_load/u64_u32_store
+ *
+ * Use a copy of a u64 value to protect against data race. This is only
+ * applicable for 32-bits architectures.
+ */
+#ifdef CONFIG_64BIT
+# define u64_u32_load_copy(var, copy)       var
+# define u64_u32_store_copy(var, copy, val) (var = val)
+#else
+# define u64_u32_load_copy(var, copy)					\
+({									\
+	u64 __val, __val_copy;						\
+	do {								\
+		__val_copy = copy;					\
+		/*							\
+		 * paired with u64_u32_store_copy(), ordering access	\
+		 * to var and copy.					\
+		 */							\
+		smp_rmb();						\
+		__val = var;						\
+	} while (__val != __val_copy);					\
+	__val;								\
+})
+# define u64_u32_store_copy(var, copy, val)				\
+do {									\
+	typeof(val) __val = (val);					\
+	var = __val;							\
+	/*								\
+	 * paired with u64_u32_load_copy(), ordering access to var and	\
+	 * copy.							\
+	 */								\
+	smp_wmb();							\
+	copy = __val;							\
+} while (0)
+#endif
+# define u64_u32_load(var)      u64_u32_load_copy(var, var##_copy)
+# define u64_u32_store(var, val) u64_u32_store_copy(var, var##_copy, val)
+
+/* CFS-related fields in a runqueue */
+struct cfs_rq {
+	struct load_weight	load;
+	unsigned int		nr_running;
+	unsigned int		h_nr_running;      /* SCHED_{NORMAL,BATCH,IDLE} */
+	unsigned int		idle_nr_running;   /* SCHED_IDLE */
+	unsigned int		idle_h_nr_running; /* SCHED_IDLE */
+
+	s64			avg_vruntime;
+	u64			avg_load;
+
+	u64			exec_clock;
+	u64			min_vruntime;
+#ifdef CONFIG_SCHED_CORE
+	unsigned int		forceidle_seq;
+	u64			min_vruntime_fi;
+#endif
+
+#ifndef CONFIG_64BIT
+	u64			min_vruntime_copy;
+#endif
+
+	struct rb_root_cached	tasks_timeline;
+
+	/*
+	 * 'curr' points to currently running entity on this cfs_rq.
+	 * It is set to NULL otherwise (i.e when none are currently running).
+	 */
+	struct sched_entity	*curr;
+	struct sched_entity	*next;
+
+#ifdef	CONFIG_SCHED_DEBUG
+	unsigned int		nr_spread_over;
+#endif
+
+#ifdef CONFIG_SMP
+	/*
+	 * CFS load tracking
+	 */
+	struct sched_avg	avg;
+#ifndef CONFIG_64BIT
+	u64			last_update_time_copy;
+#endif
+	struct {
+		raw_spinlock_t	lock ____cacheline_aligned;
+		int		nr;
+		unsigned long	load_avg;
+		unsigned long	util_avg;
+		unsigned long	runnable_avg;
+	} removed;
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	unsigned long		tg_load_avg_contrib;
+	long			propagate;
+	long			prop_runnable_sum;
+
+	/*
+	 *   h_load = weight * f(tg)
+	 *
+	 * Where f(tg) is the recursive weight fraction assigned to
+	 * this group.
+	 */
+	unsigned long		h_load;
+	u64			last_h_load_update;
+	struct sched_entity	*h_load_next;
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+#endif /* CONFIG_SMP */
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	struct rq		*rq;	/* CPU runqueue to which this cfs_rq is attached */
+
+	/*
+	 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
+	 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
+	 * (like users, containers etc.)
+	 *
+	 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a CPU.
+	 * This list is used during load balance.
+	 */
+	int			on_list;
+	struct list_head	leaf_cfs_rq_list;
+	struct task_group	*tg;	/* group that "owns" this runqueue */
+
+	/* Locally cached copy of our task_group's idle value */
+	int			idle;
+
+#ifdef CONFIG_CFS_BANDWIDTH
+	int			runtime_enabled;
+	s64			runtime_remaining;
+
+	u64			throttled_pelt_idle;
+#ifndef CONFIG_64BIT
+	u64                     throttled_pelt_idle_copy;
+#endif
+	u64			throttled_clock;
+	u64			throttled_clock_pelt;
+	u64			throttled_clock_pelt_time;
+	u64			throttled_clock_self;
+	u64			throttled_clock_self_time;
+	int			throttled;
+	int			throttle_count;
+	struct list_head	throttled_list;
+#ifdef CONFIG_SMP
+	struct list_head	throttled_csd_list;
+#endif
+#endif /* CONFIG_CFS_BANDWIDTH */
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+};
+
+static inline int rt_bandwidth_enabled(void)
+{
+	return sysctl_sched_rt_runtime >= 0;
+}
+
+/* RT IPI pull logic requires IRQ_WORK */
+#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_SMP)
+# define HAVE_RT_PUSH_IPI
+#endif
+
+/* Real-Time classes' related field in a runqueue: */
+struct rt_rq {
+	struct rt_prio_array	active;
+	unsigned int		rt_nr_running;
+	unsigned int		rr_nr_running;
+#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
+	struct {
+		int		curr; /* highest queued rt task prio */
+#ifdef CONFIG_SMP
+		int		next; /* next highest */
+#endif
+	} highest_prio;
+#endif
+#ifdef CONFIG_SMP
+	unsigned int		rt_nr_migratory;
+	unsigned int		rt_nr_total;
+	int			overloaded;
+	struct plist_head	pushable_tasks;
+
+#endif /* CONFIG_SMP */
+	int			rt_queued;
+
+	int			rt_throttled;
+	u64			rt_time;
+	u64			rt_runtime;
+	/* Nests inside the rq lock: */
+	raw_spinlock_t		rt_runtime_lock;
+
+#ifdef CONFIG_RT_GROUP_SCHED
+	unsigned int		rt_nr_boosted;
+
+	struct rq		*rq;
+	struct task_group	*tg;
+#endif
+};
+
+static inline bool rt_rq_is_runnable(struct rt_rq *rt_rq)
+{
+	return rt_rq->rt_queued && rt_rq->rt_nr_running;
+}
+
+/* Deadline class' related fields in a runqueue */
+struct dl_rq {
+	/* runqueue is an rbtree, ordered by deadline */
+	struct rb_root_cached	root;
+
+	unsigned int		dl_nr_running;
+
+#ifdef CONFIG_SMP
+	/*
+	 * Deadline values of the currently executing and the
+	 * earliest ready task on this rq. Caching these facilitates
+	 * the decision whether or not a ready but not running task
+	 * should migrate somewhere else.
+	 */
+	struct {
+		u64		curr;
+		u64		next;
+	} earliest_dl;
+
+	unsigned int		dl_nr_migratory;
+	int			overloaded;
+
+	/*
+	 * Tasks on this rq that can be pushed away. They are kept in
+	 * an rb-tree, ordered by tasks' deadlines, with caching
+	 * of the leftmost (earliest deadline) element.
+	 */
+	struct rb_root_cached	pushable_dl_tasks_root;
+#else
+	struct dl_bw		dl_bw;
+#endif
+	/*
+	 * "Active utilization" for this runqueue: increased when a
+	 * task wakes up (becomes TASK_RUNNING) and decreased when a
+	 * task blocks
+	 */
+	u64			running_bw;
+
+	/*
+	 * Utilization of the tasks "assigned" to this runqueue (including
+	 * the tasks that are in runqueue and the tasks that executed on this
+	 * CPU and blocked). Increased when a task moves to this runqueue, and
+	 * decreased when the task moves away (migrates, changes scheduling
+	 * policy, or terminates).
+	 * This is needed to compute the "inactive utilization" for the
+	 * runqueue (inactive utilization = this_bw - running_bw).
+	 */
+	u64			this_bw;
+	u64			extra_bw;
+
+	/*
+	 * Maximum available bandwidth for reclaiming by SCHED_FLAG_RECLAIM
+	 * tasks of this rq. Used in calculation of reclaimable bandwidth(GRUB).
+	 */
+	u64			max_bw;
+
+	/*
+	 * Inverse of the fraction of CPU utilization that can be reclaimed
+	 * by the GRUB algorithm.
+	 */
+	u64			bw_ratio;
+};
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+/* An entity is a task if it doesn't "own" a runqueue */
+#define entity_is_task(se)	(!se->my_q)
+
+static inline void se_update_runnable(struct sched_entity *se)
+{
+	if (!entity_is_task(se))
+		se->runnable_weight = se->my_q->h_nr_running;
+}
+
+static inline long se_runnable(struct sched_entity *se)
+{
+	if (entity_is_task(se))
+		return !!se->on_rq;
+	else
+		return se->runnable_weight;
+}
+
+#else
+#define entity_is_task(se)	1
+
+static inline void se_update_runnable(struct sched_entity *se) {}
+
+static inline long se_runnable(struct sched_entity *se)
+{
+	return !!se->on_rq;
+}
+#endif
+
+#ifdef CONFIG_SMP
+/*
+ * XXX we want to get rid of these helpers and use the full load resolution.
+ */
+static inline long se_weight(struct sched_entity *se)
+{
+	return scale_load_down(se->load.weight);
+}
+
+
+static inline bool sched_asym_prefer(int a, int b)
+{
+	return arch_asym_cpu_priority(a) > arch_asym_cpu_priority(b);
+}
+
+struct perf_domain {
+	struct em_perf_domain *em_pd;
+	struct perf_domain *next;
+	struct rcu_head rcu;
+};
+
+/* Scheduling group status flags */
+#define SG_OVERLOAD		0x1 /* More than one runnable task on a CPU. */
+#define SG_OVERUTILIZED		0x2 /* One or more CPUs are over-utilized. */
+
+/*
+ * We add the notion of a root-domain which will be used to define per-domain
+ * variables. Each exclusive cpuset essentially defines an island domain by
+ * fully partitioning the member CPUs from any other cpuset. Whenever a new
+ * exclusive cpuset is created, we also create and attach a new root-domain
+ * object.
+ *
+ */
+struct root_domain {
+	atomic_t		refcount;
+	atomic_t		rto_count;
+	struct rcu_head		rcu;
+	cpumask_var_t		span;
+	cpumask_var_t		online;
+
+	/*
+	 * Indicate pullable load on at least one CPU, e.g:
+	 * - More than one runnable task
+	 * - Running task is misfit
+	 */
+	int			overload;
+
+	/* Indicate one or more cpus over-utilized (tipping point) */
+	int			overutilized;
+
+	/*
+	 * The bit corresponding to a CPU gets set here if such CPU has more
+	 * than one runnable -deadline task (as it is below for RT tasks).
+	 */
+	cpumask_var_t		dlo_mask;
+	atomic_t		dlo_count;
+	struct dl_bw		dl_bw;
+	struct cpudl		cpudl;
+
+	/*
+	 * Indicate whether a root_domain's dl_bw has been checked or
+	 * updated. It's monotonously increasing value.
+	 *
+	 * Also, some corner cases, like 'wrap around' is dangerous, but given
+	 * that u64 is 'big enough'. So that shouldn't be a concern.
+	 */
+	u64 visit_gen;
+
+#ifdef HAVE_RT_PUSH_IPI
+	/*
+	 * For IPI pull requests, loop across the rto_mask.
+	 */
+	struct irq_work		rto_push_work;
+	raw_spinlock_t		rto_lock;
+	/* These are only updated and read within rto_lock */
+	int			rto_loop;
+	int			rto_cpu;
+	/* These atomics are updated outside of a lock */
+	atomic_t		rto_loop_next;
+	atomic_t		rto_loop_start;
+#endif
+	/*
+	 * The "RT overload" flag: it gets set if a CPU has more than
+	 * one runnable RT task.
+	 */
+	cpumask_var_t		rto_mask;
+	struct cpupri		cpupri;
+
+	unsigned long		max_cpu_capacity;
+
+	/*
+	 * NULL-terminated list of performance domains intersecting with the
+	 * CPUs of the rd. Protected by RCU.
+	 */
+	struct perf_domain __rcu *pd;
+};
+
+extern void init_defrootdomain(void);
+extern int sched_init_domains(const struct cpumask *cpu_map);
+extern void rq_attach_root(struct rq *rq, struct root_domain *rd);
+extern void sched_get_rd(struct root_domain *rd);
+extern void sched_put_rd(struct root_domain *rd);
+
+#ifdef HAVE_RT_PUSH_IPI
+extern void rto_push_irq_work_func(struct irq_work *work);
+#endif
+#endif /* CONFIG_SMP */
+
+#ifdef CONFIG_UCLAMP_TASK
+/*
+ * struct uclamp_bucket - Utilization clamp bucket
+ * @value: utilization clamp value for tasks on this clamp bucket
+ * @tasks: number of RUNNABLE tasks on this clamp bucket
+ *
+ * Keep track of how many tasks are RUNNABLE for a given utilization
+ * clamp value.
+ */
+struct uclamp_bucket {
+	unsigned long value : bits_per(SCHED_CAPACITY_SCALE);
+	unsigned long tasks : BITS_PER_LONG - bits_per(SCHED_CAPACITY_SCALE);
+};
+
+/*
+ * struct uclamp_rq - rq's utilization clamp
+ * @value: currently active clamp values for a rq
+ * @bucket: utilization clamp buckets affecting a rq
+ *
+ * Keep track of RUNNABLE tasks on a rq to aggregate their clamp values.
+ * A clamp value is affecting a rq when there is at least one task RUNNABLE
+ * (or actually running) with that value.
+ *
+ * There are up to UCLAMP_CNT possible different clamp values, currently there
+ * are only two: minimum utilization and maximum utilization.
+ *
+ * All utilization clamping values are MAX aggregated, since:
+ * - for util_min: we want to run the CPU at least at the max of the minimum
+ *   utilization required by its currently RUNNABLE tasks.
+ * - for util_max: we want to allow the CPU to run up to the max of the
+ *   maximum utilization allowed by its currently RUNNABLE tasks.
+ *
+ * Since on each system we expect only a limited number of different
+ * utilization clamp values (UCLAMP_BUCKETS), use a simple array to track
+ * the metrics required to compute all the per-rq utilization clamp values.
+ */
+struct uclamp_rq {
+	unsigned int value;
+	struct uclamp_bucket bucket[UCLAMP_BUCKETS];
+};
+
+DECLARE_STATIC_KEY_FALSE(sched_uclamp_used);
+#endif /* CONFIG_UCLAMP_TASK */
+
+struct rq;
+struct balance_callback {
+	struct balance_callback *next;
+	void (*func)(struct rq *rq);
+};
+
+/*
+ * This is the main, per-CPU runqueue data structure.
+ *
+ * Locking rule: those places that want to lock multiple runqueues
+ * (such as the load balancing or the thread migration code), lock
+ * acquire operations must be ordered by ascending &runqueue.
+ */
+struct rq {
+	/* runqueue lock: */
+	raw_spinlock_t		__lock;
+
+	/*
+	 * nr_running and cpu_load should be in the same cacheline because
+	 * remote CPUs use both these fields when doing load calculation.
+	 */
+	unsigned int		nr_running;
+#ifdef CONFIG_NUMA_BALANCING
+	unsigned int		nr_numa_running;
+	unsigned int		nr_preferred_running;
+	unsigned int		numa_migrate_on;
+#endif
+#ifdef CONFIG_NO_HZ_COMMON
+#ifdef CONFIG_SMP
+	unsigned long		last_blocked_load_update_tick;
+	unsigned int		has_blocked_load;
+	call_single_data_t	nohz_csd;
+#endif /* CONFIG_SMP */
+	unsigned int		nohz_tick_stopped;
+	atomic_t		nohz_flags;
+#endif /* CONFIG_NO_HZ_COMMON */
+
+#ifdef CONFIG_SMP
+	unsigned int		ttwu_pending;
+#endif
+	u64			nr_switches;
+
+#ifdef CONFIG_UCLAMP_TASK
+	/* Utilization clamp values based on CPU's RUNNABLE tasks */
+	struct uclamp_rq	uclamp[UCLAMP_CNT] ____cacheline_aligned;
+	unsigned int		uclamp_flags;
+#define UCLAMP_FLAG_IDLE 0x01
+#endif
+
+	struct cfs_rq		cfs;
+	struct rt_rq		rt;
+	struct dl_rq		dl;
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	/* list of leaf cfs_rq on this CPU: */
+	struct list_head	leaf_cfs_rq_list;
+	struct list_head	*tmp_alone_branch;
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+	/*
+	 * This is part of a global counter where only the total sum
+	 * over all CPUs matters. A task can increase this counter on
+	 * one CPU and if it got migrated afterwards it may decrease
+	 * it on another CPU. Always updated under the runqueue lock:
+	 */
+	unsigned int		nr_uninterruptible;
+
+	struct task_struct __rcu	*curr;
+	struct task_struct	*idle;
+	struct task_struct	*stop;
+	unsigned long		next_balance;
+	struct mm_struct	*prev_mm;
+
+	unsigned int		clock_update_flags;
+	u64			clock;
+	/* Ensure that all clocks are in the same cache line */
+	u64			clock_task ____cacheline_aligned;
+	u64			clock_pelt;
+	unsigned long		lost_idle_time;
+	u64			clock_pelt_idle;
+	u64			clock_idle;
+#ifndef CONFIG_64BIT
+	u64			clock_pelt_idle_copy;
+	u64			clock_idle_copy;
+#endif
+
+	atomic_t		nr_iowait;
+
+#ifdef CONFIG_SCHED_DEBUG
+	u64 last_seen_need_resched_ns;
+	int ticks_without_resched;
+#endif
+
+#ifdef CONFIG_MEMBARRIER
+	int membarrier_state;
+#endif
+
+#ifdef CONFIG_SMP
+	struct root_domain		*rd;
+	struct sched_domain __rcu	*sd;
+
+	unsigned long		cpu_capacity;
+	unsigned long		cpu_capacity_orig;
+
+	struct balance_callback *balance_callback;
+
+	unsigned char		nohz_idle_balance;
+	unsigned char		idle_balance;
+
+	unsigned long		misfit_task_load;
+
+	/* For active balancing */
+	int			active_balance;
+	int			push_cpu;
+	struct cpu_stop_work	active_balance_work;
+
+	/* CPU of this runqueue: */
+	int			cpu;
+	int			online;
+
+	struct list_head cfs_tasks;
+
+	struct sched_avg	avg_rt;
+	struct sched_avg	avg_dl;
+#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
+	struct sched_avg	avg_irq;
+#endif
+#ifdef CONFIG_SCHED_THERMAL_PRESSURE
+	struct sched_avg	avg_thermal;
+#endif
+	u64			idle_stamp;
+	u64			avg_idle;
+
+	unsigned long		wake_stamp;
+	u64			wake_avg_idle;
+
+	/* This is used to determine avg_idle's max value */
+	u64			max_idle_balance_cost;
+
+#ifdef CONFIG_HOTPLUG_CPU
+	struct rcuwait		hotplug_wait;
+#endif
+#endif /* CONFIG_SMP */
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+	u64			prev_irq_time;
+#endif
+#ifdef CONFIG_PARAVIRT
+	u64			prev_steal_time;
+#endif
+#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
+	u64			prev_steal_time_rq;
+#endif
+
+	/* calc_load related fields */
+	unsigned long		calc_load_update;
+	long			calc_load_active;
+
+#ifdef CONFIG_SCHED_HRTICK
+#ifdef CONFIG_SMP
+	call_single_data_t	hrtick_csd;
+#endif
+	struct hrtimer		hrtick_timer;
+	ktime_t 		hrtick_time;
+#endif
+
+#ifdef CONFIG_SCHEDSTATS
+	/* latency stats */
+	struct sched_info	rq_sched_info;
+	unsigned long long	rq_cpu_time;
+	/* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
+
+	/* sys_sched_yield() stats */
+	unsigned int		yld_count;
+
+	/* schedule() stats */
+	unsigned int		sched_count;
+	unsigned int		sched_goidle;
+
+	/* try_to_wake_up() stats */
+	unsigned int		ttwu_count;
+	unsigned int		ttwu_local;
+#endif
+
+#ifdef CONFIG_CPU_IDLE
+	/* Must be inspected within a rcu lock section */
+	struct cpuidle_state	*idle_state;
+#endif
+
+#ifdef CONFIG_SMP
+	unsigned int		nr_pinned;
+#endif
+	unsigned int		push_busy;
+	struct cpu_stop_work	push_work;
+
+#ifdef CONFIG_SCHED_CORE
+	/* per rq */
+	struct rq		*core;
+	struct task_struct	*core_pick;
+	unsigned int		core_enabled;
+	unsigned int		core_sched_seq;
+	struct rb_root		core_tree;
+
+	/* shared state -- careful with sched_core_cpu_deactivate() */
+	unsigned int		core_task_seq;
+	unsigned int		core_pick_seq;
+	unsigned long		core_cookie;
+	unsigned int		core_forceidle_count;
+	unsigned int		core_forceidle_seq;
+	unsigned int		core_forceidle_occupation;
+	u64			core_forceidle_start;
+#endif
+
+	/* Scratch cpumask to be temporarily used under rq_lock */
+	cpumask_var_t		scratch_mask;
+
+#if defined(CONFIG_CFS_BANDWIDTH) && defined(CONFIG_SMP)
+	call_single_data_t	cfsb_csd;
+	struct list_head	cfsb_csd_list;
+#endif
+};
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+
+/* CPU runqueue to which this cfs_rq is attached */
+static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
+{
+	return cfs_rq->rq;
+}
+
+#else
+
+static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
+{
+	return container_of(cfs_rq, struct rq, cfs);
+}
+#endif
+
+static inline int cpu_of(struct rq *rq)
+{
+#ifdef CONFIG_SMP
+	return rq->cpu;
+#else
+	return 0;
+#endif
+}
+
+#define MDF_PUSH	0x01
+
+static inline bool is_migration_disabled(struct task_struct *p)
+{
+#ifdef CONFIG_SMP
+	return p->migration_disabled;
+#else
+	return false;
+#endif
+}
+
+DECLARE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
+
+#define cpu_rq(cpu)		(&per_cpu(runqueues, (cpu)))
+#define this_rq()		this_cpu_ptr(&runqueues)
+#define task_rq(p)		cpu_rq(task_cpu(p))
+#define cpu_curr(cpu)		(cpu_rq(cpu)->curr)
+#define raw_rq()		raw_cpu_ptr(&runqueues)
+
+struct sched_group;
+#ifdef CONFIG_SCHED_CORE
+static inline struct cpumask *sched_group_span(struct sched_group *sg);
+
+DECLARE_STATIC_KEY_FALSE(__sched_core_enabled);
+
+static inline bool sched_core_enabled(struct rq *rq)
+{
+	return static_branch_unlikely(&__sched_core_enabled) && rq->core_enabled;
+}
+
+static inline bool sched_core_disabled(void)
+{
+	return !static_branch_unlikely(&__sched_core_enabled);
+}
+
+/*
+ * Be careful with this function; not for general use. The return value isn't
+ * stable unless you actually hold a relevant rq->__lock.
+ */
+static inline raw_spinlock_t *rq_lockp(struct rq *rq)
+{
+	if (sched_core_enabled(rq))
+		return &rq->core->__lock;
+
+	return &rq->__lock;
+}
+
+static inline raw_spinlock_t *__rq_lockp(struct rq *rq)
+{
+	if (rq->core_enabled)
+		return &rq->core->__lock;
+
+	return &rq->__lock;
+}
+
+bool cfs_prio_less(const struct task_struct *a, const struct task_struct *b,
+			bool fi);
+void task_vruntime_update(struct rq *rq, struct task_struct *p, bool in_fi);
+
+/*
+ * Helpers to check if the CPU's core cookie matches with the task's cookie
+ * when core scheduling is enabled.
+ * A special case is that the task's cookie always matches with CPU's core
+ * cookie if the CPU is in an idle core.
+ */
+static inline bool sched_cpu_cookie_match(struct rq *rq, struct task_struct *p)
+{
+	/* Ignore cookie match if core scheduler is not enabled on the CPU. */
+	if (!sched_core_enabled(rq))
+		return true;
+
+	return rq->core->core_cookie == p->core_cookie;
+}
+
+static inline bool sched_core_cookie_match(struct rq *rq, struct task_struct *p)
+{
+	bool idle_core = true;
+	int cpu;
+
+	/* Ignore cookie match if core scheduler is not enabled on the CPU. */
+	if (!sched_core_enabled(rq))
+		return true;
+
+	for_each_cpu(cpu, cpu_smt_mask(cpu_of(rq))) {
+		if (!available_idle_cpu(cpu)) {
+			idle_core = false;
+			break;
+		}
+	}
+
+	/*
+	 * A CPU in an idle core is always the best choice for tasks with
+	 * cookies.
+	 */
+	return idle_core || rq->core->core_cookie == p->core_cookie;
+}
+
+static inline bool sched_group_cookie_match(struct rq *rq,
+					    struct task_struct *p,
+					    struct sched_group *group)
+{
+	int cpu;
+
+	/* Ignore cookie match if core scheduler is not enabled on the CPU. */
+	if (!sched_core_enabled(rq))
+		return true;
+
+	for_each_cpu_and(cpu, sched_group_span(group), p->cpus_ptr) {
+		if (sched_core_cookie_match(cpu_rq(cpu), p))
+			return true;
+	}
+	return false;
+}
+
+static inline bool sched_core_enqueued(struct task_struct *p)
+{
+	return !RB_EMPTY_NODE(&p->core_node);
+}
+
+extern void sched_core_enqueue(struct rq *rq, struct task_struct *p);
+extern void sched_core_dequeue(struct rq *rq, struct task_struct *p, int flags);
+
+extern void sched_core_get(void);
+extern void sched_core_put(void);
+
+#else /* !CONFIG_SCHED_CORE */
+
+static inline bool sched_core_enabled(struct rq *rq)
+{
+	return false;
+}
+
+static inline bool sched_core_disabled(void)
+{
+	return true;
+}
+
+static inline raw_spinlock_t *rq_lockp(struct rq *rq)
+{
+	return &rq->__lock;
+}
+
+static inline raw_spinlock_t *__rq_lockp(struct rq *rq)
+{
+	return &rq->__lock;
+}
+
+static inline bool sched_cpu_cookie_match(struct rq *rq, struct task_struct *p)
+{
+	return true;
+}
+
+static inline bool sched_core_cookie_match(struct rq *rq, struct task_struct *p)
+{
+	return true;
+}
+
+static inline bool sched_group_cookie_match(struct rq *rq,
+					    struct task_struct *p,
+					    struct sched_group *group)
+{
+	return true;
+}
+#endif /* CONFIG_SCHED_CORE */
+
+static inline void lockdep_assert_rq_held(struct rq *rq)
+{
+	lockdep_assert_held(__rq_lockp(rq));
+}
+
+extern void raw_spin_rq_lock_nested(struct rq *rq, int subclass);
+extern bool raw_spin_rq_trylock(struct rq *rq);
+extern void raw_spin_rq_unlock(struct rq *rq);
+
+static inline void raw_spin_rq_lock(struct rq *rq)
+{
+	raw_spin_rq_lock_nested(rq, 0);
+}
+
+static inline void raw_spin_rq_lock_irq(struct rq *rq)
+{
+	local_irq_disable();
+	raw_spin_rq_lock(rq);
+}
+
+static inline void raw_spin_rq_unlock_irq(struct rq *rq)
+{
+	raw_spin_rq_unlock(rq);
+	local_irq_enable();
+}
+
+static inline unsigned long _raw_spin_rq_lock_irqsave(struct rq *rq)
+{
+	unsigned long flags;
+	local_irq_save(flags);
+	raw_spin_rq_lock(rq);
+	return flags;
+}
+
+static inline void raw_spin_rq_unlock_irqrestore(struct rq *rq, unsigned long flags)
+{
+	raw_spin_rq_unlock(rq);
+	local_irq_restore(flags);
+}
+
+#define raw_spin_rq_lock_irqsave(rq, flags)	\
+do {						\
+	flags = _raw_spin_rq_lock_irqsave(rq);	\
+} while (0)
+
+#ifdef CONFIG_SCHED_SMT
+extern void __update_idle_core(struct rq *rq);
+
+static inline void update_idle_core(struct rq *rq)
+{
+	if (static_branch_unlikely(&sched_smt_present))
+		__update_idle_core(rq);
+}
+
+#else
+static inline void update_idle_core(struct rq *rq) { }
+#endif
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static inline struct task_struct *task_of(struct sched_entity *se)
+{
+	SCHED_WARN_ON(!entity_is_task(se));
+	return container_of(se, struct task_struct, se);
+}
+
+static inline struct cfs_rq *task_cfs_rq(struct task_struct *p)
+{
+	return p->se.cfs_rq;
+}
+
+/* runqueue on which this entity is (to be) queued */
+static inline struct cfs_rq *cfs_rq_of(const struct sched_entity *se)
+{
+	return se->cfs_rq;
+}
+
+/* runqueue "owned" by this group */
+static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp)
+{
+	return grp->my_q;
+}
+
+#else
+
+#define task_of(_se)	container_of(_se, struct task_struct, se)
+
+static inline struct cfs_rq *task_cfs_rq(const struct task_struct *p)
+{
+	return &task_rq(p)->cfs;
+}
+
+static inline struct cfs_rq *cfs_rq_of(const struct sched_entity *se)
+{
+	const struct task_struct *p = task_of(se);
+	struct rq *rq = task_rq(p);
+
+	return &rq->cfs;
+}
+
+/* runqueue "owned" by this group */
+static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp)
+{
+	return NULL;
+}
+#endif
+
+extern void update_rq_clock(struct rq *rq);
+
+/*
+ * rq::clock_update_flags bits
+ *
+ * %RQCF_REQ_SKIP - will request skipping of clock update on the next
+ *  call to __schedule(). This is an optimisation to avoid
+ *  neighbouring rq clock updates.
+ *
+ * %RQCF_ACT_SKIP - is set from inside of __schedule() when skipping is
+ *  in effect and calls to update_rq_clock() are being ignored.
+ *
+ * %RQCF_UPDATED - is a debug flag that indicates whether a call has been
+ *  made to update_rq_clock() since the last time rq::lock was pinned.
+ *
+ * If inside of __schedule(), clock_update_flags will have been
+ * shifted left (a left shift is a cheap operation for the fast path
+ * to promote %RQCF_REQ_SKIP to %RQCF_ACT_SKIP), so you must use,
+ *
+ *	if (rq-clock_update_flags >= RQCF_UPDATED)
+ *
+ * to check if %RQCF_UPDATED is set. It'll never be shifted more than
+ * one position though, because the next rq_unpin_lock() will shift it
+ * back.
+ */
+#define RQCF_REQ_SKIP		0x01
+#define RQCF_ACT_SKIP		0x02
+#define RQCF_UPDATED		0x04
+
+static inline void assert_clock_updated(struct rq *rq)
+{
+	/*
+	 * The only reason for not seeing a clock update since the
+	 * last rq_pin_lock() is if we're currently skipping updates.
+	 */
+	SCHED_WARN_ON(rq->clock_update_flags < RQCF_ACT_SKIP);
+}
+
+static inline u64 rq_clock(struct rq *rq)
+{
+	lockdep_assert_rq_held(rq);
+	assert_clock_updated(rq);
+
+	return rq->clock;
+}
+
+static inline u64 rq_clock_task(struct rq *rq)
+{
+	lockdep_assert_rq_held(rq);
+	assert_clock_updated(rq);
+
+	return rq->clock_task;
+}
+
+/**
+ * By default the decay is the default pelt decay period.
+ * The decay shift can change the decay period in
+ * multiples of 32.
+ *  Decay shift		Decay period(ms)
+ *	0			32
+ *	1			64
+ *	2			128
+ *	3			256
+ *	4			512
+ */
+extern int sched_thermal_decay_shift;
+
+static inline u64 rq_clock_thermal(struct rq *rq)
+{
+	return rq_clock_task(rq) >> sched_thermal_decay_shift;
+}
+
+static inline void rq_clock_skip_update(struct rq *rq)
+{
+	lockdep_assert_rq_held(rq);
+	rq->clock_update_flags |= RQCF_REQ_SKIP;
+}
+
+/*
+ * See rt task throttling, which is the only time a skip
+ * request is canceled.
+ */
+static inline void rq_clock_cancel_skipupdate(struct rq *rq)
+{
+	lockdep_assert_rq_held(rq);
+	rq->clock_update_flags &= ~RQCF_REQ_SKIP;
+}
+
+/*
+ * During cpu offlining and rq wide unthrottling, we can trigger
+ * an update_rq_clock() for several cfs and rt runqueues (Typically
+ * when using list_for_each_entry_*)
+ * rq_clock_start_loop_update() can be called after updating the clock
+ * once and before iterating over the list to prevent multiple update.
+ * After the iterative traversal, we need to call rq_clock_stop_loop_update()
+ * to clear RQCF_ACT_SKIP of rq->clock_update_flags.
+ */
+static inline void rq_clock_start_loop_update(struct rq *rq)
+{
+	lockdep_assert_rq_held(rq);
+	SCHED_WARN_ON(rq->clock_update_flags & RQCF_ACT_SKIP);
+	rq->clock_update_flags |= RQCF_ACT_SKIP;
+}
+
+static inline void rq_clock_stop_loop_update(struct rq *rq)
+{
+	lockdep_assert_rq_held(rq);
+	rq->clock_update_flags &= ~RQCF_ACT_SKIP;
+}
+
+struct rq_flags {
+	unsigned long flags;
+	struct pin_cookie cookie;
+#ifdef CONFIG_SCHED_DEBUG
+	/*
+	 * A copy of (rq::clock_update_flags & RQCF_UPDATED) for the
+	 * current pin context is stashed here in case it needs to be
+	 * restored in rq_repin_lock().
+	 */
+	unsigned int clock_update_flags;
+#endif
+};
+
+extern struct balance_callback balance_push_callback;
+
+/*
+ * Lockdep annotation that avoids accidental unlocks; it's like a
+ * sticky/continuous lockdep_assert_held().
+ *
+ * This avoids code that has access to 'struct rq *rq' (basically everything in
+ * the scheduler) from accidentally unlocking the rq if they do not also have a
+ * copy of the (on-stack) 'struct rq_flags rf'.
+ *
+ * Also see Documentation/locking/lockdep-design.rst.
+ */
+static inline void rq_pin_lock(struct rq *rq, struct rq_flags *rf)
+{
+	rf->cookie = lockdep_pin_lock(__rq_lockp(rq));
+
+#ifdef CONFIG_SCHED_DEBUG
+	rq->clock_update_flags &= (RQCF_REQ_SKIP|RQCF_ACT_SKIP);
+	rf->clock_update_flags = 0;
+#ifdef CONFIG_SMP
+	SCHED_WARN_ON(rq->balance_callback && rq->balance_callback != &balance_push_callback);
+#endif
+#endif
+}
+
+static inline void rq_unpin_lock(struct rq *rq, struct rq_flags *rf)
+{
+#ifdef CONFIG_SCHED_DEBUG
+	if (rq->clock_update_flags > RQCF_ACT_SKIP)
+		rf->clock_update_flags = RQCF_UPDATED;
+#endif
+
+	lockdep_unpin_lock(__rq_lockp(rq), rf->cookie);
+}
+
+static inline void rq_repin_lock(struct rq *rq, struct rq_flags *rf)
+{
+	lockdep_repin_lock(__rq_lockp(rq), rf->cookie);
+
+#ifdef CONFIG_SCHED_DEBUG
+	/*
+	 * Restore the value we stashed in @rf for this pin context.
+	 */
+	rq->clock_update_flags |= rf->clock_update_flags;
+#endif
+}
+
+struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf)
+	__acquires(rq->lock);
+
+struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf)
+	__acquires(p->pi_lock)
+	__acquires(rq->lock);
+
+static inline void __task_rq_unlock(struct rq *rq, struct rq_flags *rf)
+	__releases(rq->lock)
+{
+	rq_unpin_lock(rq, rf);
+	raw_spin_rq_unlock(rq);
+}
+
+static inline void
+task_rq_unlock(struct rq *rq, struct task_struct *p, struct rq_flags *rf)
+	__releases(rq->lock)
+	__releases(p->pi_lock)
+{
+	rq_unpin_lock(rq, rf);
+	raw_spin_rq_unlock(rq);
+	raw_spin_unlock_irqrestore(&p->pi_lock, rf->flags);
+}
+
+static inline void
+rq_lock_irqsave(struct rq *rq, struct rq_flags *rf)
+	__acquires(rq->lock)
+{
+	raw_spin_rq_lock_irqsave(rq, rf->flags);
+	rq_pin_lock(rq, rf);
+}
+
+static inline void
+rq_lock_irq(struct rq *rq, struct rq_flags *rf)
+	__acquires(rq->lock)
+{
+	raw_spin_rq_lock_irq(rq);
+	rq_pin_lock(rq, rf);
+}
+
+static inline void
+rq_lock(struct rq *rq, struct rq_flags *rf)
+	__acquires(rq->lock)
+{
+	raw_spin_rq_lock(rq);
+	rq_pin_lock(rq, rf);
+}
+
+static inline void
+rq_unlock_irqrestore(struct rq *rq, struct rq_flags *rf)
+	__releases(rq->lock)
+{
+	rq_unpin_lock(rq, rf);
+	raw_spin_rq_unlock_irqrestore(rq, rf->flags);
+}
+
+static inline void
+rq_unlock_irq(struct rq *rq, struct rq_flags *rf)
+	__releases(rq->lock)
+{
+	rq_unpin_lock(rq, rf);
+	raw_spin_rq_unlock_irq(rq);
+}
+
+static inline void
+rq_unlock(struct rq *rq, struct rq_flags *rf)
+	__releases(rq->lock)
+{
+	rq_unpin_lock(rq, rf);
+	raw_spin_rq_unlock(rq);
+}
+
+DEFINE_LOCK_GUARD_1(rq_lock, struct rq,
+		    rq_lock(_T->lock, &_T->rf),
+		    rq_unlock(_T->lock, &_T->rf),
+		    struct rq_flags rf)
+
+DEFINE_LOCK_GUARD_1(rq_lock_irq, struct rq,
+		    rq_lock_irq(_T->lock, &_T->rf),
+		    rq_unlock_irq(_T->lock, &_T->rf),
+		    struct rq_flags rf)
+
+DEFINE_LOCK_GUARD_1(rq_lock_irqsave, struct rq,
+		    rq_lock_irqsave(_T->lock, &_T->rf),
+		    rq_unlock_irqrestore(_T->lock, &_T->rf),
+		    struct rq_flags rf)
+
+static inline struct rq *
+this_rq_lock_irq(struct rq_flags *rf)
+	__acquires(rq->lock)
+{
+	struct rq *rq;
+
+	local_irq_disable();
+	rq = this_rq();
+	rq_lock(rq, rf);
+	return rq;
+}
+
+#ifdef CONFIG_NUMA
+enum numa_topology_type {
+	NUMA_DIRECT,
+	NUMA_GLUELESS_MESH,
+	NUMA_BACKPLANE,
+};
+extern enum numa_topology_type sched_numa_topology_type;
+extern int sched_max_numa_distance;
+extern bool find_numa_distance(int distance);
+extern void sched_init_numa(int offline_node);
+extern void sched_update_numa(int cpu, bool online);
+extern void sched_domains_numa_masks_set(unsigned int cpu);
+extern void sched_domains_numa_masks_clear(unsigned int cpu);
+extern int sched_numa_find_closest(const struct cpumask *cpus, int cpu);
+#else
+static inline void sched_init_numa(int offline_node) { }
+static inline void sched_update_numa(int cpu, bool online) { }
+static inline void sched_domains_numa_masks_set(unsigned int cpu) { }
+static inline void sched_domains_numa_masks_clear(unsigned int cpu) { }
+static inline int sched_numa_find_closest(const struct cpumask *cpus, int cpu)
+{
+	return nr_cpu_ids;
+}
+#endif
+
+#ifdef CONFIG_NUMA_BALANCING
+/* The regions in numa_faults array from task_struct */
+enum numa_faults_stats {
+	NUMA_MEM = 0,
+	NUMA_CPU,
+	NUMA_MEMBUF,
+	NUMA_CPUBUF
+};
+extern void sched_setnuma(struct task_struct *p, int node);
+extern int migrate_task_to(struct task_struct *p, int cpu);
+extern int migrate_swap(struct task_struct *p, struct task_struct *t,
+			int cpu, int scpu);
+extern void init_numa_balancing(unsigned long clone_flags, struct task_struct *p);
+#else
+static inline void
+init_numa_balancing(unsigned long clone_flags, struct task_struct *p)
+{
+}
+#endif /* CONFIG_NUMA_BALANCING */
+
+#ifdef CONFIG_SMP
+
+static inline void
+queue_balance_callback(struct rq *rq,
+		       struct balance_callback *head,
+		       void (*func)(struct rq *rq))
+{
+	lockdep_assert_rq_held(rq);
+
+	/*
+	 * Don't (re)queue an already queued item; nor queue anything when
+	 * balance_push() is active, see the comment with
+	 * balance_push_callback.
+	 */
+	if (unlikely(head->next || rq->balance_callback == &balance_push_callback))
+		return;
+
+	head->func = func;
+	head->next = rq->balance_callback;
+	rq->balance_callback = head;
+}
+
+#define rcu_dereference_check_sched_domain(p) \
+	rcu_dereference_check((p), \
+			      lockdep_is_held(&sched_domains_mutex))
+
+/*
+ * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
+ * See destroy_sched_domains: call_rcu for details.
+ *
+ * The domain tree of any CPU may only be accessed from within
+ * preempt-disabled sections.
+ */
+#define for_each_domain(cpu, __sd) \
+	for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); \
+			__sd; __sd = __sd->parent)
+
+/* A mask of all the SD flags that have the SDF_SHARED_CHILD metaflag */
+#define SD_FLAG(name, mflags) (name * !!((mflags) & SDF_SHARED_CHILD)) |
+static const unsigned int SD_SHARED_CHILD_MASK =
+#include <linux/sched/sd_flags.h>
+0;
+#undef SD_FLAG
+
+/**
+ * highest_flag_domain - Return highest sched_domain containing flag.
+ * @cpu:	The CPU whose highest level of sched domain is to
+ *		be returned.
+ * @flag:	The flag to check for the highest sched_domain
+ *		for the given CPU.
+ *
+ * Returns the highest sched_domain of a CPU which contains @flag. If @flag has
+ * the SDF_SHARED_CHILD metaflag, all the children domains also have @flag.
+ */
+static inline struct sched_domain *highest_flag_domain(int cpu, int flag)
+{
+	struct sched_domain *sd, *hsd = NULL;
+
+	for_each_domain(cpu, sd) {
+		if (sd->flags & flag) {
+			hsd = sd;
+			continue;
+		}
+
+		/*
+		 * Stop the search if @flag is known to be shared at lower
+		 * levels. It will not be found further up.
+		 */
+		if (flag & SD_SHARED_CHILD_MASK)
+			break;
+	}
+
+	return hsd;
+}
+
+static inline struct sched_domain *lowest_flag_domain(int cpu, int flag)
+{
+	struct sched_domain *sd;
+
+	for_each_domain(cpu, sd) {
+		if (sd->flags & flag)
+			break;
+	}
+
+	return sd;
+}
+
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_llc);
+DECLARE_PER_CPU(int, sd_llc_size);
+DECLARE_PER_CPU(int, sd_llc_id);
+DECLARE_PER_CPU(struct sched_domain_shared __rcu *, sd_llc_shared);
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_numa);
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing);
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_asym_cpucapacity);
+extern struct static_key_false sched_asym_cpucapacity;
+
+static __always_inline bool sched_asym_cpucap_active(void)
+{
+	return static_branch_unlikely(&sched_asym_cpucapacity);
+}
+
+struct sched_group_capacity {
+	atomic_t		ref;
+	/*
+	 * CPU capacity of this group, SCHED_CAPACITY_SCALE being max capacity
+	 * for a single CPU.
+	 */
+	unsigned long		capacity;
+	unsigned long		min_capacity;		/* Min per-CPU capacity in group */
+	unsigned long		max_capacity;		/* Max per-CPU capacity in group */
+	unsigned long		next_update;
+	int			imbalance;		/* XXX unrelated to capacity but shared group state */
+
+#ifdef CONFIG_SCHED_DEBUG
+	int			id;
+#endif
+
+	unsigned long		cpumask[];		/* Balance mask */
+};
+
+struct sched_group {
+	struct sched_group	*next;			/* Must be a circular list */
+	atomic_t		ref;
+
+	unsigned int		group_weight;
+	unsigned int		cores;
+	struct sched_group_capacity *sgc;
+	int			asym_prefer_cpu;	/* CPU of highest priority in group */
+	int			flags;
+
+	/*
+	 * The CPUs this group covers.
+	 *
+	 * NOTE: this field is variable length. (Allocated dynamically
+	 * by attaching extra space to the end of the structure,
+	 * depending on how many CPUs the kernel has booted up with)
+	 */
+	unsigned long		cpumask[];
+};
+
+static inline struct cpumask *sched_group_span(struct sched_group *sg)
+{
+	return to_cpumask(sg->cpumask);
+}
+
+/*
+ * See build_balance_mask().
+ */
+static inline struct cpumask *group_balance_mask(struct sched_group *sg)
+{
+	return to_cpumask(sg->sgc->cpumask);
+}
+
+extern int group_balance_cpu(struct sched_group *sg);
+
+#ifdef CONFIG_SCHED_DEBUG
+void update_sched_domain_debugfs(void);
+void dirty_sched_domain_sysctl(int cpu);
+#else
+static inline void update_sched_domain_debugfs(void)
+{
+}
+static inline void dirty_sched_domain_sysctl(int cpu)
+{
+}
+#endif
+
+extern int sched_update_scaling(void);
+
+static inline const struct cpumask *task_user_cpus(struct task_struct *p)
+{
+	if (!p->user_cpus_ptr)
+		return cpu_possible_mask; /* &init_task.cpus_mask */
+	return p->user_cpus_ptr;
+}
+#endif /* CONFIG_SMP */
+
+#include "stats.h"
+
+#if defined(CONFIG_SCHED_CORE) && defined(CONFIG_SCHEDSTATS)
+
+extern void __sched_core_account_forceidle(struct rq *rq);
+
+static inline void sched_core_account_forceidle(struct rq *rq)
+{
+	if (schedstat_enabled())
+		__sched_core_account_forceidle(rq);
+}
+
+extern void __sched_core_tick(struct rq *rq);
+
+static inline void sched_core_tick(struct rq *rq)
+{
+	if (sched_core_enabled(rq) && schedstat_enabled())
+		__sched_core_tick(rq);
+}
+
+#else
+
+static inline void sched_core_account_forceidle(struct rq *rq) {}
+
+static inline void sched_core_tick(struct rq *rq) {}
+
+#endif /* CONFIG_SCHED_CORE && CONFIG_SCHEDSTATS */
+
+#ifdef CONFIG_CGROUP_SCHED
+
+/*
+ * Return the group to which this tasks belongs.
+ *
+ * We cannot use task_css() and friends because the cgroup subsystem
+ * changes that value before the cgroup_subsys::attach() method is called,
+ * therefore we cannot pin it and might observe the wrong value.
+ *
+ * The same is true for autogroup's p->signal->autogroup->tg, the autogroup
+ * core changes this before calling sched_move_task().
+ *
+ * Instead we use a 'copy' which is updated from sched_move_task() while
+ * holding both task_struct::pi_lock and rq::lock.
+ */
+static inline struct task_group *task_group(struct task_struct *p)
+{
+	return p->sched_task_group;
+}
+
+/* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
+static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
+{
+#if defined(CONFIG_FAIR_GROUP_SCHED) || defined(CONFIG_RT_GROUP_SCHED)
+	struct task_group *tg = task_group(p);
+#endif
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	set_task_rq_fair(&p->se, p->se.cfs_rq, tg->cfs_rq[cpu]);
+	p->se.cfs_rq = tg->cfs_rq[cpu];
+	p->se.parent = tg->se[cpu];
+	p->se.depth = tg->se[cpu] ? tg->se[cpu]->depth + 1 : 0;
+#endif
+
+#ifdef CONFIG_RT_GROUP_SCHED
+	p->rt.rt_rq  = tg->rt_rq[cpu];
+	p->rt.parent = tg->rt_se[cpu];
+#endif
+}
+
+#else /* CONFIG_CGROUP_SCHED */
+
+static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
+static inline struct task_group *task_group(struct task_struct *p)
+{
+	return NULL;
+}
+
+#endif /* CONFIG_CGROUP_SCHED */
+
+static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
+{
+	set_task_rq(p, cpu);
+#ifdef CONFIG_SMP
+	/*
+	 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
+	 * successfully executed on another CPU. We must ensure that updates of
+	 * per-task data have been completed by this moment.
+	 */
+	smp_wmb();
+	WRITE_ONCE(task_thread_info(p)->cpu, cpu);
+	p->wake_cpu = cpu;
+#endif
+}
+
+/*
+ * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
+ */
+#ifdef CONFIG_SCHED_DEBUG
+# define const_debug __read_mostly
+#else
+# define const_debug const
+#endif
+
+#define SCHED_FEAT(name, enabled)	\
+	__SCHED_FEAT_##name ,
+
+enum {
+#include "features.h"
+	__SCHED_FEAT_NR,
+};
+
+#undef SCHED_FEAT
+
+#ifdef CONFIG_SCHED_DEBUG
+
+/*
+ * To support run-time toggling of sched features, all the translation units
+ * (but core.c) reference the sysctl_sched_features defined in core.c.
+ */
+extern const_debug unsigned int sysctl_sched_features;
+
+#ifdef CONFIG_JUMP_LABEL
+#define SCHED_FEAT(name, enabled)					\
+static __always_inline bool static_branch_##name(struct static_key *key) \
+{									\
+	return static_key_##enabled(key);				\
+}
+
+#include "features.h"
+#undef SCHED_FEAT
+
+extern struct static_key sched_feat_keys[__SCHED_FEAT_NR];
+#define sched_feat(x) (static_branch_##x(&sched_feat_keys[__SCHED_FEAT_##x]))
+
+#else /* !CONFIG_JUMP_LABEL */
+
+#define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
+
+#endif /* CONFIG_JUMP_LABEL */
+
+#else /* !SCHED_DEBUG */
+
+/*
+ * Each translation unit has its own copy of sysctl_sched_features to allow
+ * constants propagation at compile time and compiler optimization based on
+ * features default.
+ */
+#define SCHED_FEAT(name, enabled)	\
+	(1UL << __SCHED_FEAT_##name) * enabled |
+static const_debug __maybe_unused unsigned int sysctl_sched_features =
+#include "features.h"
+	0;
+#undef SCHED_FEAT
+
+#define sched_feat(x) !!(sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
+
+#endif /* SCHED_DEBUG */
+
+extern struct static_key_false sched_numa_balancing;
+extern struct static_key_false sched_schedstats;
+
+static inline u64 global_rt_period(void)
+{
+	return (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
+}
+
+static inline u64 global_rt_runtime(void)
+{
+	if (sysctl_sched_rt_runtime < 0)
+		return RUNTIME_INF;
+
+	return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
+}
+
+static inline int task_current(struct rq *rq, struct task_struct *p)
+{
+	return rq->curr == p;
+}
+
+static inline int task_on_cpu(struct rq *rq, struct task_struct *p)
+{
+#ifdef CONFIG_SMP
+	return p->on_cpu;
+#else
+	return task_current(rq, p);
+#endif
+}
+
+static inline int task_on_rq_queued(struct task_struct *p)
+{
+	return p->on_rq == TASK_ON_RQ_QUEUED;
+}
+
+static inline int task_on_rq_migrating(struct task_struct *p)
+{
+	return READ_ONCE(p->on_rq) == TASK_ON_RQ_MIGRATING;
+}
+
+/* Wake flags. The first three directly map to some SD flag value */
+#define WF_EXEC         0x02 /* Wakeup after exec; maps to SD_BALANCE_EXEC */
+#define WF_FORK         0x04 /* Wakeup after fork; maps to SD_BALANCE_FORK */
+#define WF_TTWU         0x08 /* Wakeup;            maps to SD_BALANCE_WAKE */
+
+#define WF_SYNC         0x10 /* Waker goes to sleep after wakeup */
+#define WF_MIGRATED     0x20 /* Internal use, task got migrated */
+#define WF_CURRENT_CPU  0x40 /* Prefer to move the wakee to the current CPU. */
+
+#ifdef CONFIG_SMP
+static_assert(WF_EXEC == SD_BALANCE_EXEC);
+static_assert(WF_FORK == SD_BALANCE_FORK);
+static_assert(WF_TTWU == SD_BALANCE_WAKE);
+#endif
+
+/*
+ * To aid in avoiding the subversion of "niceness" due to uneven distribution
+ * of tasks with abnormal "nice" values across CPUs the contribution that
+ * each task makes to its run queue's load is weighted according to its
+ * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
+ * scaled version of the new time slice allocation that they receive on time
+ * slice expiry etc.
+ */
+
+#define WEIGHT_IDLEPRIO		3
+#define WMULT_IDLEPRIO		1431655765
+
+extern const int		sched_prio_to_weight[40];
+extern const u32		sched_prio_to_wmult[40];
+
+/*
+ * {de,en}queue flags:
+ *
+ * DEQUEUE_SLEEP  - task is no longer runnable
+ * ENQUEUE_WAKEUP - task just became runnable
+ *
+ * SAVE/RESTORE - an otherwise spurious dequeue/enqueue, done to ensure tasks
+ *                are in a known state which allows modification. Such pairs
+ *                should preserve as much state as possible.
+ *
+ * MOVE - paired with SAVE/RESTORE, explicitly does not preserve the location
+ *        in the runqueue.
+ *
+ * ENQUEUE_HEAD      - place at front of runqueue (tail if not specified)
+ * ENQUEUE_REPLENISH - CBS (replenish runtime and postpone deadline)
+ * ENQUEUE_MIGRATED  - the task was migrated during wakeup
+ *
+ */
+
+#define DEQUEUE_SLEEP		0x01
+#define DEQUEUE_SAVE		0x02 /* Matches ENQUEUE_RESTORE */
+#define DEQUEUE_MOVE		0x04 /* Matches ENQUEUE_MOVE */
+#define DEQUEUE_NOCLOCK		0x08 /* Matches ENQUEUE_NOCLOCK */
+
+#define ENQUEUE_WAKEUP		0x01
+#define ENQUEUE_RESTORE		0x02
+#define ENQUEUE_MOVE		0x04
+#define ENQUEUE_NOCLOCK		0x08
+
+#define ENQUEUE_HEAD		0x10
+#define ENQUEUE_REPLENISH	0x20
+#ifdef CONFIG_SMP
+#define ENQUEUE_MIGRATED	0x40
+#else
+#define ENQUEUE_MIGRATED	0x00
+#endif
+#define ENQUEUE_INITIAL		0x80
+
+#define RETRY_TASK		((void *)-1UL)
+
+struct affinity_context {
+	const struct cpumask *new_mask;
+	struct cpumask *user_mask;
+	unsigned int flags;
+};
+
+struct sched_class {
+
+#ifdef CONFIG_UCLAMP_TASK
+	int uclamp_enabled;
+#endif
+
+	void (*enqueue_task) (struct rq *rq, struct task_struct *p, int flags);
+	void (*dequeue_task) (struct rq *rq, struct task_struct *p, int flags);
+	void (*yield_task)   (struct rq *rq);
+	bool (*yield_to_task)(struct rq *rq, struct task_struct *p);
+
+	void (*check_preempt_curr)(struct rq *rq, struct task_struct *p, int flags);
+
+	struct task_struct *(*pick_next_task)(struct rq *rq);
+
+	void (*put_prev_task)(struct rq *rq, struct task_struct *p);
+	void (*set_next_task)(struct rq *rq, struct task_struct *p, bool first);
+
+#ifdef CONFIG_SMP
+	int (*balance)(struct rq *rq, struct task_struct *prev, struct rq_flags *rf);
+	int  (*select_task_rq)(struct task_struct *p, int task_cpu, int flags);
+
+	struct task_struct * (*pick_task)(struct rq *rq);
+
+	void (*migrate_task_rq)(struct task_struct *p, int new_cpu);
+
+	void (*task_woken)(struct rq *this_rq, struct task_struct *task);
+
+	void (*set_cpus_allowed)(struct task_struct *p, struct affinity_context *ctx);
+
+	void (*rq_online)(struct rq *rq);
+	void (*rq_offline)(struct rq *rq);
+
+	struct rq *(*find_lock_rq)(struct task_struct *p, struct rq *rq);
+#endif
+
+	void (*task_tick)(struct rq *rq, struct task_struct *p, int queued);
+	void (*task_fork)(struct task_struct *p);
+	void (*task_dead)(struct task_struct *p);
+
+	/*
+	 * The switched_from() call is allowed to drop rq->lock, therefore we
+	 * cannot assume the switched_from/switched_to pair is serialized by
+	 * rq->lock. They are however serialized by p->pi_lock.
+	 */
+	void (*switched_from)(struct rq *this_rq, struct task_struct *task);
+	void (*switched_to)  (struct rq *this_rq, struct task_struct *task);
+	void (*prio_changed) (struct rq *this_rq, struct task_struct *task,
+			      int oldprio);
+
+	unsigned int (*get_rr_interval)(struct rq *rq,
+					struct task_struct *task);
+
+	void (*update_curr)(struct rq *rq);
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	void (*task_change_group)(struct task_struct *p);
+#endif
+
+#ifdef CONFIG_SCHED_CORE
+	int (*task_is_throttled)(struct task_struct *p, int cpu);
+#endif
+};
+
+static inline void put_prev_task(struct rq *rq, struct task_struct *prev)
+{
+	WARN_ON_ONCE(rq->curr != prev);
+	prev->sched_class->put_prev_task(rq, prev);
+}
+
+static inline void set_next_task(struct rq *rq, struct task_struct *next)
+{
+	next->sched_class->set_next_task(rq, next, false);
+}
+
+
+/*
+ * Helper to define a sched_class instance; each one is placed in a separate
+ * section which is ordered by the linker script:
+ *
+ *   include/asm-generic/vmlinux.lds.h
+ *
+ * *CAREFUL* they are laid out in *REVERSE* order!!!
+ *
+ * Also enforce alignment on the instance, not the type, to guarantee layout.
+ */
+#define DEFINE_SCHED_CLASS(name) \
+const struct sched_class name##_sched_class \
+	__aligned(__alignof__(struct sched_class)) \
+	__section("__" #name "_sched_class")
+
+/* Defined in include/asm-generic/vmlinux.lds.h */
+extern struct sched_class __sched_class_highest[];
+extern struct sched_class __sched_class_lowest[];
+
+#define for_class_range(class, _from, _to) \
+	for (class = (_from); class < (_to); class++)
+
+#define for_each_class(class) \
+	for_class_range(class, __sched_class_highest, __sched_class_lowest)
+
+#define sched_class_above(_a, _b)	((_a) < (_b))
+
+extern const struct sched_class stop_sched_class;
+extern const struct sched_class dl_sched_class;
+extern const struct sched_class rt_sched_class;
+extern const struct sched_class fair_sched_class;
+extern const struct sched_class idle_sched_class;
+
+static inline bool sched_stop_runnable(struct rq *rq)
+{
+	return rq->stop && task_on_rq_queued(rq->stop);
+}
+
+static inline bool sched_dl_runnable(struct rq *rq)
+{
+	return rq->dl.dl_nr_running > 0;
+}
+
+static inline bool sched_rt_runnable(struct rq *rq)
+{
+	return rq->rt.rt_queued > 0;
+}
+
+static inline bool sched_fair_runnable(struct rq *rq)
+{
+	return rq->cfs.nr_running > 0;
+}
+
+extern struct task_struct *pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf);
+extern struct task_struct *pick_next_task_idle(struct rq *rq);
+
+#define SCA_CHECK		0x01
+#define SCA_MIGRATE_DISABLE	0x02
+#define SCA_MIGRATE_ENABLE	0x04
+#define SCA_USER		0x08
+
+#ifdef CONFIG_SMP
+
+extern void update_group_capacity(struct sched_domain *sd, int cpu);
+
+extern void trigger_load_balance(struct rq *rq);
+
+extern void set_cpus_allowed_common(struct task_struct *p, struct affinity_context *ctx);
+
+static inline struct task_struct *get_push_task(struct rq *rq)
+{
+	struct task_struct *p = rq->curr;
+
+	lockdep_assert_rq_held(rq);
+
+	if (rq->push_busy)
+		return NULL;
+
+	if (p->nr_cpus_allowed == 1)
+		return NULL;
+
+	if (p->migration_disabled)
+		return NULL;
+
+	rq->push_busy = true;
+	return get_task_struct(p);
+}
+
+extern int push_cpu_stop(void *arg);
+
+#endif
+
+#ifdef CONFIG_CPU_IDLE
+static inline void idle_set_state(struct rq *rq,
+				  struct cpuidle_state *idle_state)
+{
+	rq->idle_state = idle_state;
+}
+
+static inline struct cpuidle_state *idle_get_state(struct rq *rq)
+{
+	SCHED_WARN_ON(!rcu_read_lock_held());
+
+	return rq->idle_state;
+}
+#else
+static inline void idle_set_state(struct rq *rq,
+				  struct cpuidle_state *idle_state)
+{
+}
+
+static inline struct cpuidle_state *idle_get_state(struct rq *rq)
+{
+	return NULL;
+}
+#endif
+
+extern void schedule_idle(void);
+asmlinkage void schedule_user(void);
+
+extern void sysrq_sched_debug_show(void);
+extern void sched_init_granularity(void);
+extern void update_max_interval(void);
+
+extern void init_sched_dl_class(void);
+extern void init_sched_rt_class(void);
+extern void init_sched_fair_class(void);
+
+extern void reweight_task(struct task_struct *p, int prio);
+
+extern void resched_curr(struct rq *rq);
+extern void resched_cpu(int cpu);
+
+extern struct rt_bandwidth def_rt_bandwidth;
+extern void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime);
+extern bool sched_rt_bandwidth_account(struct rt_rq *rt_rq);
+
+extern void init_dl_task_timer(struct sched_dl_entity *dl_se);
+extern void init_dl_inactive_task_timer(struct sched_dl_entity *dl_se);
+
+#define BW_SHIFT		20
+#define BW_UNIT			(1 << BW_SHIFT)
+#define RATIO_SHIFT		8
+#define MAX_BW_BITS		(64 - BW_SHIFT)
+#define MAX_BW			((1ULL << MAX_BW_BITS) - 1)
+unsigned long to_ratio(u64 period, u64 runtime);
+
+extern void init_entity_runnable_average(struct sched_entity *se);
+extern void post_init_entity_util_avg(struct task_struct *p);
+
+#ifdef CONFIG_NO_HZ_FULL
+extern bool sched_can_stop_tick(struct rq *rq);
+extern int __init sched_tick_offload_init(void);
+
+/*
+ * Tick may be needed by tasks in the runqueue depending on their policy and
+ * requirements. If tick is needed, lets send the target an IPI to kick it out of
+ * nohz mode if necessary.
+ */
+static inline void sched_update_tick_dependency(struct rq *rq)
+{
+	int cpu = cpu_of(rq);
+
+	if (!tick_nohz_full_cpu(cpu))
+		return;
+
+	if (sched_can_stop_tick(rq))
+		tick_nohz_dep_clear_cpu(cpu, TICK_DEP_BIT_SCHED);
+	else
+		tick_nohz_dep_set_cpu(cpu, TICK_DEP_BIT_SCHED);
+}
+#else
+static inline int sched_tick_offload_init(void) { return 0; }
+static inline void sched_update_tick_dependency(struct rq *rq) { }
+#endif
+
+static inline void add_nr_running(struct rq *rq, unsigned count)
+{
+	unsigned prev_nr = rq->nr_running;
+
+	rq->nr_running = prev_nr + count;
+	if (trace_sched_update_nr_running_tp_enabled()) {
+		call_trace_sched_update_nr_running(rq, count);
+	}
+
+#ifdef CONFIG_SMP
+	if (prev_nr < 2 && rq->nr_running >= 2) {
+		if (!READ_ONCE(rq->rd->overload))
+			WRITE_ONCE(rq->rd->overload, 1);
+	}
+#endif
+
+	sched_update_tick_dependency(rq);
+}
+
+static inline void sub_nr_running(struct rq *rq, unsigned count)
+{
+	rq->nr_running -= count;
+	if (trace_sched_update_nr_running_tp_enabled()) {
+		call_trace_sched_update_nr_running(rq, -count);
+	}
+
+	/* Check if we still need preemption */
+	sched_update_tick_dependency(rq);
+}
+
+extern void activate_task(struct rq *rq, struct task_struct *p, int flags);
+extern void deactivate_task(struct rq *rq, struct task_struct *p, int flags);
+
+extern void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags);
+
+#ifdef CONFIG_PREEMPT_RT
+#define SCHED_NR_MIGRATE_BREAK 8
+#else
+#define SCHED_NR_MIGRATE_BREAK 32
+#endif
+
+extern const_debug unsigned int sysctl_sched_nr_migrate;
+extern const_debug unsigned int sysctl_sched_migration_cost;
+
+extern unsigned int sysctl_sched_base_slice;
+
+#ifdef CONFIG_SCHED_DEBUG
+extern int sysctl_resched_latency_warn_ms;
+extern int sysctl_resched_latency_warn_once;
+
+extern unsigned int sysctl_sched_tunable_scaling;
+
+extern unsigned int sysctl_numa_balancing_scan_delay;
+extern unsigned int sysctl_numa_balancing_scan_period_min;
+extern unsigned int sysctl_numa_balancing_scan_period_max;
+extern unsigned int sysctl_numa_balancing_scan_size;
+extern unsigned int sysctl_numa_balancing_hot_threshold;
+#endif
+
+#ifdef CONFIG_SCHED_HRTICK
+
+/*
+ * Use hrtick when:
+ *  - enabled by features
+ *  - hrtimer is actually high res
+ */
+static inline int hrtick_enabled(struct rq *rq)
+{
+	if (!cpu_active(cpu_of(rq)))
+		return 0;
+	return hrtimer_is_hres_active(&rq->hrtick_timer);
+}
+
+static inline int hrtick_enabled_fair(struct rq *rq)
+{
+	if (!sched_feat(HRTICK))
+		return 0;
+	return hrtick_enabled(rq);
+}
+
+static inline int hrtick_enabled_dl(struct rq *rq)
+{
+	if (!sched_feat(HRTICK_DL))
+		return 0;
+	return hrtick_enabled(rq);
+}
+
+void hrtick_start(struct rq *rq, u64 delay);
+
+#else
+
+static inline int hrtick_enabled_fair(struct rq *rq)
+{
+	return 0;
+}
+
+static inline int hrtick_enabled_dl(struct rq *rq)
+{
+	return 0;
+}
+
+static inline int hrtick_enabled(struct rq *rq)
+{
+	return 0;
+}
+
+#endif /* CONFIG_SCHED_HRTICK */
+
+#ifndef arch_scale_freq_tick
+static __always_inline
+void arch_scale_freq_tick(void)
+{
+}
+#endif
+
+#ifndef arch_scale_freq_capacity
+/**
+ * arch_scale_freq_capacity - get the frequency scale factor of a given CPU.
+ * @cpu: the CPU in question.
+ *
+ * Return: the frequency scale factor normalized against SCHED_CAPACITY_SCALE, i.e.
+ *
+ *     f_curr
+ *     ------ * SCHED_CAPACITY_SCALE
+ *     f_max
+ */
+static __always_inline
+unsigned long arch_scale_freq_capacity(int cpu)
+{
+	return SCHED_CAPACITY_SCALE;
+}
+#endif
+
+#ifdef CONFIG_SCHED_DEBUG
+/*
+ * In double_lock_balance()/double_rq_lock(), we use raw_spin_rq_lock() to
+ * acquire rq lock instead of rq_lock(). So at the end of these two functions
+ * we need to call double_rq_clock_clear_update() to clear RQCF_UPDATED of
+ * rq->clock_update_flags to avoid the WARN_DOUBLE_CLOCK warning.
+ */
+static inline void double_rq_clock_clear_update(struct rq *rq1, struct rq *rq2)
+{
+	rq1->clock_update_flags &= (RQCF_REQ_SKIP|RQCF_ACT_SKIP);
+	/* rq1 == rq2 for !CONFIG_SMP, so just clear RQCF_UPDATED once. */
+#ifdef CONFIG_SMP
+	rq2->clock_update_flags &= (RQCF_REQ_SKIP|RQCF_ACT_SKIP);
+#endif
+}
+#else
+static inline void double_rq_clock_clear_update(struct rq *rq1, struct rq *rq2) {}
+#endif
+
+#define DEFINE_LOCK_GUARD_2(name, type, _lock, _unlock, ...)		\
+__DEFINE_UNLOCK_GUARD(name, type, _unlock, type *lock2; __VA_ARGS__) \
+static inline class_##name##_t class_##name##_constructor(type *lock, type *lock2) \
+{ class_##name##_t _t = { .lock = lock, .lock2 = lock2 }, *_T = &_t;	\
+  _lock; return _t; }
+
+#ifdef CONFIG_SMP
+
+static inline bool rq_order_less(struct rq *rq1, struct rq *rq2)
+{
+#ifdef CONFIG_SCHED_CORE
+	/*
+	 * In order to not have {0,2},{1,3} turn into into an AB-BA,
+	 * order by core-id first and cpu-id second.
+	 *
+	 * Notably:
+	 *
+	 *	double_rq_lock(0,3); will take core-0, core-1 lock
+	 *	double_rq_lock(1,2); will take core-1, core-0 lock
+	 *
+	 * when only cpu-id is considered.
+	 */
+	if (rq1->core->cpu < rq2->core->cpu)
+		return true;
+	if (rq1->core->cpu > rq2->core->cpu)
+		return false;
+
+	/*
+	 * __sched_core_flip() relies on SMT having cpu-id lock order.
+	 */
+#endif
+	return rq1->cpu < rq2->cpu;
+}
+
+extern void double_rq_lock(struct rq *rq1, struct rq *rq2);
+
+#ifdef CONFIG_PREEMPTION
+
+/*
+ * fair double_lock_balance: Safely acquires both rq->locks in a fair
+ * way at the expense of forcing extra atomic operations in all
+ * invocations.  This assures that the double_lock is acquired using the
+ * same underlying policy as the spinlock_t on this architecture, which
+ * reduces latency compared to the unfair variant below.  However, it
+ * also adds more overhead and therefore may reduce throughput.
+ */
+static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
+	__releases(this_rq->lock)
+	__acquires(busiest->lock)
+	__acquires(this_rq->lock)
+{
+	raw_spin_rq_unlock(this_rq);
+	double_rq_lock(this_rq, busiest);
+
+	return 1;
+}
+
+#else
+/*
+ * Unfair double_lock_balance: Optimizes throughput at the expense of
+ * latency by eliminating extra atomic operations when the locks are
+ * already in proper order on entry.  This favors lower CPU-ids and will
+ * grant the double lock to lower CPUs over higher ids under contention,
+ * regardless of entry order into the function.
+ */
+static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
+	__releases(this_rq->lock)
+	__acquires(busiest->lock)
+	__acquires(this_rq->lock)
+{
+	if (__rq_lockp(this_rq) == __rq_lockp(busiest) ||
+	    likely(raw_spin_rq_trylock(busiest))) {
+		double_rq_clock_clear_update(this_rq, busiest);
+		return 0;
+	}
+
+	if (rq_order_less(this_rq, busiest)) {
+		raw_spin_rq_lock_nested(busiest, SINGLE_DEPTH_NESTING);
+		double_rq_clock_clear_update(this_rq, busiest);
+		return 0;
+	}
+
+	raw_spin_rq_unlock(this_rq);
+	double_rq_lock(this_rq, busiest);
+
+	return 1;
+}
+
+#endif /* CONFIG_PREEMPTION */
+
+/*
+ * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
+ */
+static inline int double_lock_balance(struct rq *this_rq, struct rq *busiest)
+{
+	lockdep_assert_irqs_disabled();
+
+	return _double_lock_balance(this_rq, busiest);
+}
+
+static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
+	__releases(busiest->lock)
+{
+	if (__rq_lockp(this_rq) != __rq_lockp(busiest))
+		raw_spin_rq_unlock(busiest);
+	lock_set_subclass(&__rq_lockp(this_rq)->dep_map, 0, _RET_IP_);
+}
+
+static inline void double_lock(spinlock_t *l1, spinlock_t *l2)
+{
+	if (l1 > l2)
+		swap(l1, l2);
+
+	spin_lock(l1);
+	spin_lock_nested(l2, SINGLE_DEPTH_NESTING);
+}
+
+static inline void double_lock_irq(spinlock_t *l1, spinlock_t *l2)
+{
+	if (l1 > l2)
+		swap(l1, l2);
+
+	spin_lock_irq(l1);
+	spin_lock_nested(l2, SINGLE_DEPTH_NESTING);
+}
+
+static inline void double_raw_lock(raw_spinlock_t *l1, raw_spinlock_t *l2)
+{
+	if (l1 > l2)
+		swap(l1, l2);
+
+	raw_spin_lock(l1);
+	raw_spin_lock_nested(l2, SINGLE_DEPTH_NESTING);
+}
+
+static inline void double_raw_unlock(raw_spinlock_t *l1, raw_spinlock_t *l2)
+{
+	raw_spin_unlock(l1);
+	raw_spin_unlock(l2);
+}
+
+DEFINE_LOCK_GUARD_2(double_raw_spinlock, raw_spinlock_t,
+		    double_raw_lock(_T->lock, _T->lock2),
+		    double_raw_unlock(_T->lock, _T->lock2))
+
+/*
+ * double_rq_unlock - safely unlock two runqueues
+ *
+ * Note this does not restore interrupts like task_rq_unlock,
+ * you need to do so manually after calling.
+ */
+static inline void double_rq_unlock(struct rq *rq1, struct rq *rq2)
+	__releases(rq1->lock)
+	__releases(rq2->lock)
+{
+	if (__rq_lockp(rq1) != __rq_lockp(rq2))
+		raw_spin_rq_unlock(rq2);
+	else
+		__release(rq2->lock);
+	raw_spin_rq_unlock(rq1);
+}
+
+extern void set_rq_online (struct rq *rq);
+extern void set_rq_offline(struct rq *rq);
+extern bool sched_smp_initialized;
+
+#else /* CONFIG_SMP */
+
+/*
+ * double_rq_lock - safely lock two runqueues
+ *
+ * Note this does not disable interrupts like task_rq_lock,
+ * you need to do so manually before calling.
+ */
+static inline void double_rq_lock(struct rq *rq1, struct rq *rq2)
+	__acquires(rq1->lock)
+	__acquires(rq2->lock)
+{
+	WARN_ON_ONCE(!irqs_disabled());
+	WARN_ON_ONCE(rq1 != rq2);
+	raw_spin_rq_lock(rq1);
+	__acquire(rq2->lock);	/* Fake it out ;) */
+	double_rq_clock_clear_update(rq1, rq2);
+}
+
+/*
+ * double_rq_unlock - safely unlock two runqueues
+ *
+ * Note this does not restore interrupts like task_rq_unlock,
+ * you need to do so manually after calling.
+ */
+static inline void double_rq_unlock(struct rq *rq1, struct rq *rq2)
+	__releases(rq1->lock)
+	__releases(rq2->lock)
+{
+	WARN_ON_ONCE(rq1 != rq2);
+	raw_spin_rq_unlock(rq1);
+	__release(rq2->lock);
+}
+
+#endif
+
+DEFINE_LOCK_GUARD_2(double_rq_lock, struct rq,
+		    double_rq_lock(_T->lock, _T->lock2),
+		    double_rq_unlock(_T->lock, _T->lock2))
+
+extern struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq);
+extern struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq);
+
+#ifdef	CONFIG_SCHED_DEBUG
+extern bool sched_debug_verbose;
+
+extern void print_cfs_stats(struct seq_file *m, int cpu);
+extern void print_rt_stats(struct seq_file *m, int cpu);
+extern void print_dl_stats(struct seq_file *m, int cpu);
+extern void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq);
+extern void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq);
+extern void print_dl_rq(struct seq_file *m, int cpu, struct dl_rq *dl_rq);
+
+extern void resched_latency_warn(int cpu, u64 latency);
+#ifdef CONFIG_NUMA_BALANCING
+extern void
+show_numa_stats(struct task_struct *p, struct seq_file *m);
+extern void
+print_numa_stats(struct seq_file *m, int node, unsigned long tsf,
+	unsigned long tpf, unsigned long gsf, unsigned long gpf);
+#endif /* CONFIG_NUMA_BALANCING */
+#else
+static inline void resched_latency_warn(int cpu, u64 latency) {}
+#endif /* CONFIG_SCHED_DEBUG */
+
+extern void init_cfs_rq(struct cfs_rq *cfs_rq);
+extern void init_rt_rq(struct rt_rq *rt_rq);
+extern void init_dl_rq(struct dl_rq *dl_rq);
+
+extern void cfs_bandwidth_usage_inc(void);
+extern void cfs_bandwidth_usage_dec(void);
+
+#ifdef CONFIG_NO_HZ_COMMON
+#define NOHZ_BALANCE_KICK_BIT	0
+#define NOHZ_STATS_KICK_BIT	1
+#define NOHZ_NEWILB_KICK_BIT	2
+#define NOHZ_NEXT_KICK_BIT	3
+
+/* Run rebalance_domains() */
+#define NOHZ_BALANCE_KICK	BIT(NOHZ_BALANCE_KICK_BIT)
+/* Update blocked load */
+#define NOHZ_STATS_KICK		BIT(NOHZ_STATS_KICK_BIT)
+/* Update blocked load when entering idle */
+#define NOHZ_NEWILB_KICK	BIT(NOHZ_NEWILB_KICK_BIT)
+/* Update nohz.next_balance */
+#define NOHZ_NEXT_KICK		BIT(NOHZ_NEXT_KICK_BIT)
+
+#define NOHZ_KICK_MASK	(NOHZ_BALANCE_KICK | NOHZ_STATS_KICK | NOHZ_NEXT_KICK)
+
+#define nohz_flags(cpu)	(&cpu_rq(cpu)->nohz_flags)
+
+extern void nohz_balance_exit_idle(struct rq *rq);
+#else
+static inline void nohz_balance_exit_idle(struct rq *rq) { }
+#endif
+
+#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
+extern void nohz_run_idle_balance(int cpu);
+#else
+static inline void nohz_run_idle_balance(int cpu) { }
+#endif
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+struct irqtime {
+	u64			total;
+	u64			tick_delta;
+	u64			irq_start_time;
+	struct u64_stats_sync	sync;
+};
+
+DECLARE_PER_CPU(struct irqtime, cpu_irqtime);
+
+/*
+ * Returns the irqtime minus the softirq time computed by ksoftirqd.
+ * Otherwise ksoftirqd's sum_exec_runtime is subtracted its own runtime
+ * and never move forward.
+ */
+static inline u64 irq_time_read(int cpu)
+{
+	struct irqtime *irqtime = &per_cpu(cpu_irqtime, cpu);
+	unsigned int seq;
+	u64 total;
+
+	do {
+		seq = __u64_stats_fetch_begin(&irqtime->sync);
+		total = irqtime->total;
+	} while (__u64_stats_fetch_retry(&irqtime->sync, seq));
+
+	return total;
+}
+#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
+
+#ifdef CONFIG_CPU_FREQ
+DECLARE_PER_CPU(struct update_util_data __rcu *, cpufreq_update_util_data);
+
+/**
+ * cpufreq_update_util - Take a note about CPU utilization changes.
+ * @rq: Runqueue to carry out the update for.
+ * @flags: Update reason flags.
+ *
+ * This function is called by the scheduler on the CPU whose utilization is
+ * being updated.
+ *
+ * It can only be called from RCU-sched read-side critical sections.
+ *
+ * The way cpufreq is currently arranged requires it to evaluate the CPU
+ * performance state (frequency/voltage) on a regular basis to prevent it from
+ * being stuck in a completely inadequate performance level for too long.
+ * That is not guaranteed to happen if the updates are only triggered from CFS
+ * and DL, though, because they may not be coming in if only RT tasks are
+ * active all the time (or there are RT tasks only).
+ *
+ * As a workaround for that issue, this function is called periodically by the
+ * RT sched class to trigger extra cpufreq updates to prevent it from stalling,
+ * but that really is a band-aid.  Going forward it should be replaced with
+ * solutions targeted more specifically at RT tasks.
+ */
+static inline void cpufreq_update_util(struct rq *rq, unsigned int flags)
+{
+	struct update_util_data *data;
+
+	data = rcu_dereference_sched(*per_cpu_ptr(&cpufreq_update_util_data,
+						  cpu_of(rq)));
+	if (data)
+		data->func(data, rq_clock(rq), flags);
+}
+#else
+static inline void cpufreq_update_util(struct rq *rq, unsigned int flags) {}
+#endif /* CONFIG_CPU_FREQ */
+
+#ifdef arch_scale_freq_capacity
+# ifndef arch_scale_freq_invariant
+#  define arch_scale_freq_invariant()	true
+# endif
+#else
+# define arch_scale_freq_invariant()	false
+#endif
+
+#ifdef CONFIG_SMP
+static inline unsigned long capacity_orig_of(int cpu)
+{
+	return cpu_rq(cpu)->cpu_capacity_orig;
+}
+
+/**
+ * enum cpu_util_type - CPU utilization type
+ * @FREQUENCY_UTIL:	Utilization used to select frequency
+ * @ENERGY_UTIL:	Utilization used during energy calculation
+ *
+ * The utilization signals of all scheduling classes (CFS/RT/DL) and IRQ time
+ * need to be aggregated differently depending on the usage made of them. This
+ * enum is used within effective_cpu_util() to differentiate the types of
+ * utilization expected by the callers, and adjust the aggregation accordingly.
+ */
+enum cpu_util_type {
+	FREQUENCY_UTIL,
+	ENERGY_UTIL,
+};
+
+unsigned long effective_cpu_util(int cpu, unsigned long util_cfs,
+				 enum cpu_util_type type,
+				 struct task_struct *p);
+
+/*
+ * Verify the fitness of task @p to run on @cpu taking into account the
+ * CPU original capacity and the runtime/deadline ratio of the task.
+ *
+ * The function will return true if the original capacity of @cpu is
+ * greater than or equal to task's deadline density right shifted by
+ * (BW_SHIFT - SCHED_CAPACITY_SHIFT) and false otherwise.
+ */
+static inline bool dl_task_fits_capacity(struct task_struct *p, int cpu)
+{
+	unsigned long cap = arch_scale_cpu_capacity(cpu);
+
+	return cap >= p->dl.dl_density >> (BW_SHIFT - SCHED_CAPACITY_SHIFT);
+}
+
+static inline unsigned long cpu_bw_dl(struct rq *rq)
+{
+	return (rq->dl.running_bw * SCHED_CAPACITY_SCALE) >> BW_SHIFT;
+}
+
+static inline unsigned long cpu_util_dl(struct rq *rq)
+{
+	return READ_ONCE(rq->avg_dl.util_avg);
+}
+
+
+extern unsigned long cpu_util_cfs(int cpu);
+extern unsigned long cpu_util_cfs_boost(int cpu);
+
+static inline unsigned long cpu_util_rt(struct rq *rq)
+{
+	return READ_ONCE(rq->avg_rt.util_avg);
+}
+#endif
+
+#ifdef CONFIG_UCLAMP_TASK
+unsigned long uclamp_eff_value(struct task_struct *p, enum uclamp_id clamp_id);
+
+static inline unsigned long uclamp_rq_get(struct rq *rq,
+					  enum uclamp_id clamp_id)
+{
+	return READ_ONCE(rq->uclamp[clamp_id].value);
+}
+
+static inline void uclamp_rq_set(struct rq *rq, enum uclamp_id clamp_id,
+				 unsigned int value)
+{
+	WRITE_ONCE(rq->uclamp[clamp_id].value, value);
+}
+
+static inline bool uclamp_rq_is_idle(struct rq *rq)
+{
+	return rq->uclamp_flags & UCLAMP_FLAG_IDLE;
+}
+
+/**
+ * uclamp_rq_util_with - clamp @util with @rq and @p effective uclamp values.
+ * @rq:		The rq to clamp against. Must not be NULL.
+ * @util:	The util value to clamp.
+ * @p:		The task to clamp against. Can be NULL if you want to clamp
+ *		against @rq only.
+ *
+ * Clamps the passed @util to the max(@rq, @p) effective uclamp values.
+ *
+ * If sched_uclamp_used static key is disabled, then just return the util
+ * without any clamping since uclamp aggregation at the rq level in the fast
+ * path is disabled, rendering this operation a NOP.
+ *
+ * Use uclamp_eff_value() if you don't care about uclamp values at rq level. It
+ * will return the correct effective uclamp value of the task even if the
+ * static key is disabled.
+ */
+static __always_inline
+unsigned long uclamp_rq_util_with(struct rq *rq, unsigned long util,
+				  struct task_struct *p)
+{
+	unsigned long min_util = 0;
+	unsigned long max_util = 0;
+
+	if (!static_branch_likely(&sched_uclamp_used))
+		return util;
+
+	if (p) {
+		min_util = uclamp_eff_value(p, UCLAMP_MIN);
+		max_util = uclamp_eff_value(p, UCLAMP_MAX);
+
+		/*
+		 * Ignore last runnable task's max clamp, as this task will
+		 * reset it. Similarly, no need to read the rq's min clamp.
+		 */
+		if (uclamp_rq_is_idle(rq))
+			goto out;
+	}
+
+	min_util = max_t(unsigned long, min_util, uclamp_rq_get(rq, UCLAMP_MIN));
+	max_util = max_t(unsigned long, max_util, uclamp_rq_get(rq, UCLAMP_MAX));
+out:
+	/*
+	 * Since CPU's {min,max}_util clamps are MAX aggregated considering
+	 * RUNNABLE tasks with _different_ clamps, we can end up with an
+	 * inversion. Fix it now when the clamps are applied.
+	 */
+	if (unlikely(min_util >= max_util))
+		return min_util;
+
+	return clamp(util, min_util, max_util);
+}
+
+/* Is the rq being capped/throttled by uclamp_max? */
+static inline bool uclamp_rq_is_capped(struct rq *rq)
+{
+	unsigned long rq_util;
+	unsigned long max_util;
+
+	if (!static_branch_likely(&sched_uclamp_used))
+		return false;
+
+	rq_util = cpu_util_cfs(cpu_of(rq)) + cpu_util_rt(rq);
+	max_util = READ_ONCE(rq->uclamp[UCLAMP_MAX].value);
+
+	return max_util != SCHED_CAPACITY_SCALE && rq_util >= max_util;
+}
+
+/*
+ * When uclamp is compiled in, the aggregation at rq level is 'turned off'
+ * by default in the fast path and only gets turned on once userspace performs
+ * an operation that requires it.
+ *
+ * Returns true if userspace opted-in to use uclamp and aggregation at rq level
+ * hence is active.
+ */
+static inline bool uclamp_is_used(void)
+{
+	return static_branch_likely(&sched_uclamp_used);
+}
+#else /* CONFIG_UCLAMP_TASK */
+static inline unsigned long uclamp_eff_value(struct task_struct *p,
+					     enum uclamp_id clamp_id)
+{
+	if (clamp_id == UCLAMP_MIN)
+		return 0;
+
+	return SCHED_CAPACITY_SCALE;
+}
+
+static inline
+unsigned long uclamp_rq_util_with(struct rq *rq, unsigned long util,
+				  struct task_struct *p)
+{
+	return util;
+}
+
+static inline bool uclamp_rq_is_capped(struct rq *rq) { return false; }
+
+static inline bool uclamp_is_used(void)
+{
+	return false;
+}
+
+static inline unsigned long uclamp_rq_get(struct rq *rq,
+					  enum uclamp_id clamp_id)
+{
+	if (clamp_id == UCLAMP_MIN)
+		return 0;
+
+	return SCHED_CAPACITY_SCALE;
+}
+
+static inline void uclamp_rq_set(struct rq *rq, enum uclamp_id clamp_id,
+				 unsigned int value)
+{
+}
+
+static inline bool uclamp_rq_is_idle(struct rq *rq)
+{
+	return false;
+}
+#endif /* CONFIG_UCLAMP_TASK */
+
+#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
+static inline unsigned long cpu_util_irq(struct rq *rq)
+{
+	return rq->avg_irq.util_avg;
+}
+
+static inline
+unsigned long scale_irq_capacity(unsigned long util, unsigned long irq, unsigned long max)
+{
+	util *= (max - irq);
+	util /= max;
+
+	return util;
+
+}
+#else
+static inline unsigned long cpu_util_irq(struct rq *rq)
+{
+	return 0;
+}
+
+static inline
+unsigned long scale_irq_capacity(unsigned long util, unsigned long irq, unsigned long max)
+{
+	return util;
+}
+#endif
+
+#if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
+
+#define perf_domain_span(pd) (to_cpumask(((pd)->em_pd->cpus)))
+
+DECLARE_STATIC_KEY_FALSE(sched_energy_present);
+
+static inline bool sched_energy_enabled(void)
+{
+	return static_branch_unlikely(&sched_energy_present);
+}
+
+#else /* ! (CONFIG_ENERGY_MODEL && CONFIG_CPU_FREQ_GOV_SCHEDUTIL) */
+
+#define perf_domain_span(pd) NULL
+static inline bool sched_energy_enabled(void) { return false; }
+
+#endif /* CONFIG_ENERGY_MODEL && CONFIG_CPU_FREQ_GOV_SCHEDUTIL */
+
+#ifdef CONFIG_MEMBARRIER
+/*
+ * The scheduler provides memory barriers required by membarrier between:
+ * - prior user-space memory accesses and store to rq->membarrier_state,
+ * - store to rq->membarrier_state and following user-space memory accesses.
+ * In the same way it provides those guarantees around store to rq->curr.
+ */
+static inline void membarrier_switch_mm(struct rq *rq,
+					struct mm_struct *prev_mm,
+					struct mm_struct *next_mm)
+{
+	int membarrier_state;
+
+	if (prev_mm == next_mm)
+		return;
+
+	membarrier_state = atomic_read(&next_mm->membarrier_state);
+	if (READ_ONCE(rq->membarrier_state) == membarrier_state)
+		return;
+
+	WRITE_ONCE(rq->membarrier_state, membarrier_state);
+}
+#else
+static inline void membarrier_switch_mm(struct rq *rq,
+					struct mm_struct *prev_mm,
+					struct mm_struct *next_mm)
+{
+}
+#endif
+
+#ifdef CONFIG_SMP
+static inline bool is_per_cpu_kthread(struct task_struct *p)
+{
+	if (!(p->flags & PF_KTHREAD))
+		return false;
+
+	if (p->nr_cpus_allowed != 1)
+		return false;
+
+	return true;
+}
+#endif
+
+extern void swake_up_all_locked(struct swait_queue_head *q);
+extern void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait);
+
+extern int try_to_wake_up(struct task_struct *tsk, unsigned int state, int wake_flags);
+
+#ifdef CONFIG_PREEMPT_DYNAMIC
+extern int preempt_dynamic_mode;
+extern int sched_dynamic_mode(const char *str);
+extern void sched_dynamic_update(int mode);
+#endif
+
+static inline void update_current_exec_runtime(struct task_struct *curr,
+						u64 now, u64 delta_exec)
+{
+	curr->se.sum_exec_runtime += delta_exec;
+	account_group_exec_runtime(curr, delta_exec);
+
+	curr->se.exec_start = now;
+	cgroup_account_cputime(curr, delta_exec);
+}
+
+#ifdef CONFIG_SCHED_MM_CID
+
+#define SCHED_MM_CID_PERIOD_NS	(100ULL * 1000000)	/* 100ms */
+#define MM_CID_SCAN_DELAY	100			/* 100ms */
+
+extern raw_spinlock_t cid_lock;
+extern int use_cid_lock;
+
+extern void sched_mm_cid_migrate_from(struct task_struct *t);
+extern void sched_mm_cid_migrate_to(struct rq *dst_rq, struct task_struct *t);
+extern void task_tick_mm_cid(struct rq *rq, struct task_struct *curr);
+extern void init_sched_mm_cid(struct task_struct *t);
+
+static inline void __mm_cid_put(struct mm_struct *mm, int cid)
+{
+	if (cid < 0)
+		return;
+	cpumask_clear_cpu(cid, mm_cidmask(mm));
+}
+
+/*
+ * The per-mm/cpu cid can have the MM_CID_LAZY_PUT flag set or transition to
+ * the MM_CID_UNSET state without holding the rq lock, but the rq lock needs to
+ * be held to transition to other states.
+ *
+ * State transitions synchronized with cmpxchg or try_cmpxchg need to be
+ * consistent across cpus, which prevents use of this_cpu_cmpxchg.
+ */
+static inline void mm_cid_put_lazy(struct task_struct *t)
+{
+	struct mm_struct *mm = t->mm;
+	struct mm_cid __percpu *pcpu_cid = mm->pcpu_cid;
+	int cid;
+
+	lockdep_assert_irqs_disabled();
+	cid = __this_cpu_read(pcpu_cid->cid);
+	if (!mm_cid_is_lazy_put(cid) ||
+	    !try_cmpxchg(&this_cpu_ptr(pcpu_cid)->cid, &cid, MM_CID_UNSET))
+		return;
+	__mm_cid_put(mm, mm_cid_clear_lazy_put(cid));
+}
+
+static inline int mm_cid_pcpu_unset(struct mm_struct *mm)
+{
+	struct mm_cid __percpu *pcpu_cid = mm->pcpu_cid;
+	int cid, res;
+
+	lockdep_assert_irqs_disabled();
+	cid = __this_cpu_read(pcpu_cid->cid);
+	for (;;) {
+		if (mm_cid_is_unset(cid))
+			return MM_CID_UNSET;
+		/*
+		 * Attempt transition from valid or lazy-put to unset.
+		 */
+		res = cmpxchg(&this_cpu_ptr(pcpu_cid)->cid, cid, MM_CID_UNSET);
+		if (res == cid)
+			break;
+		cid = res;
+	}
+	return cid;
+}
+
+static inline void mm_cid_put(struct mm_struct *mm)
+{
+	int cid;
+
+	lockdep_assert_irqs_disabled();
+	cid = mm_cid_pcpu_unset(mm);
+	if (cid == MM_CID_UNSET)
+		return;
+	__mm_cid_put(mm, mm_cid_clear_lazy_put(cid));
+}
+
+static inline int __mm_cid_try_get(struct mm_struct *mm)
+{
+	struct cpumask *cpumask;
+	int cid;
+
+	cpumask = mm_cidmask(mm);
+	/*
+	 * Retry finding first zero bit if the mask is temporarily
+	 * filled. This only happens during concurrent remote-clear
+	 * which owns a cid without holding a rq lock.
+	 */
+	for (;;) {
+		cid = cpumask_first_zero(cpumask);
+		if (cid < nr_cpu_ids)
+			break;
+		cpu_relax();
+	}
+	if (cpumask_test_and_set_cpu(cid, cpumask))
+		return -1;
+	return cid;
+}
+
+/*
+ * Save a snapshot of the current runqueue time of this cpu
+ * with the per-cpu cid value, allowing to estimate how recently it was used.
+ */
+static inline void mm_cid_snapshot_time(struct rq *rq, struct mm_struct *mm)
+{
+	struct mm_cid *pcpu_cid = per_cpu_ptr(mm->pcpu_cid, cpu_of(rq));
+
+	lockdep_assert_rq_held(rq);
+	WRITE_ONCE(pcpu_cid->time, rq->clock);
+}
+
+static inline int __mm_cid_get(struct rq *rq, struct mm_struct *mm)
+{
+	int cid;
+
+	/*
+	 * All allocations (even those using the cid_lock) are lock-free. If
+	 * use_cid_lock is set, hold the cid_lock to perform cid allocation to
+	 * guarantee forward progress.
+	 */
+	if (!READ_ONCE(use_cid_lock)) {
+		cid = __mm_cid_try_get(mm);
+		if (cid >= 0)
+			goto end;
+		raw_spin_lock(&cid_lock);
+	} else {
+		raw_spin_lock(&cid_lock);
+		cid = __mm_cid_try_get(mm);
+		if (cid >= 0)
+			goto unlock;
+	}
+
+	/*
+	 * cid concurrently allocated. Retry while forcing following
+	 * allocations to use the cid_lock to ensure forward progress.
+	 */
+	WRITE_ONCE(use_cid_lock, 1);
+	/*
+	 * Set use_cid_lock before allocation. Only care about program order
+	 * because this is only required for forward progress.
+	 */
+	barrier();
+	/*
+	 * Retry until it succeeds. It is guaranteed to eventually succeed once
+	 * all newcoming allocations observe the use_cid_lock flag set.
+	 */
+	do {
+		cid = __mm_cid_try_get(mm);
+		cpu_relax();
+	} while (cid < 0);
+	/*
+	 * Allocate before clearing use_cid_lock. Only care about
+	 * program order because this is for forward progress.
+	 */
+	barrier();
+	WRITE_ONCE(use_cid_lock, 0);
+unlock:
+	raw_spin_unlock(&cid_lock);
+end:
+	mm_cid_snapshot_time(rq, mm);
+	return cid;
+}
+
+static inline int mm_cid_get(struct rq *rq, struct mm_struct *mm)
+{
+	struct mm_cid __percpu *pcpu_cid = mm->pcpu_cid;
+	struct cpumask *cpumask;
+	int cid;
+
+	lockdep_assert_rq_held(rq);
+	cpumask = mm_cidmask(mm);
+	cid = __this_cpu_read(pcpu_cid->cid);
+	if (mm_cid_is_valid(cid)) {
+		mm_cid_snapshot_time(rq, mm);
+		return cid;
+	}
+	if (mm_cid_is_lazy_put(cid)) {
+		if (try_cmpxchg(&this_cpu_ptr(pcpu_cid)->cid, &cid, MM_CID_UNSET))
+			__mm_cid_put(mm, mm_cid_clear_lazy_put(cid));
+	}
+	cid = __mm_cid_get(rq, mm);
+	__this_cpu_write(pcpu_cid->cid, cid);
+	return cid;
+}
+
+static inline void switch_mm_cid(struct rq *rq,
+				 struct task_struct *prev,
+				 struct task_struct *next)
+{
+	/*
+	 * Provide a memory barrier between rq->curr store and load of
+	 * {prev,next}->mm->pcpu_cid[cpu] on rq->curr->mm transition.
+	 *
+	 * Should be adapted if context_switch() is modified.
+	 */
+	if (!next->mm) {                                // to kernel
+		/*
+		 * user -> kernel transition does not guarantee a barrier, but
+		 * we can use the fact that it performs an atomic operation in
+		 * mmgrab().
+		 */
+		if (prev->mm)                           // from user
+			smp_mb__after_mmgrab();
+		/*
+		 * kernel -> kernel transition does not change rq->curr->mm
+		 * state. It stays NULL.
+		 */
+	} else {                                        // to user
+		/*
+		 * kernel -> user transition does not provide a barrier
+		 * between rq->curr store and load of {prev,next}->mm->pcpu_cid[cpu].
+		 * Provide it here.
+		 */
+		if (!prev->mm)                          // from kernel
+			smp_mb();
+		/*
+		 * user -> user transition guarantees a memory barrier through
+		 * switch_mm() when current->mm changes. If current->mm is
+		 * unchanged, no barrier is needed.
+		 */
+	}
+	if (prev->mm_cid_active) {
+		mm_cid_snapshot_time(rq, prev->mm);
+		mm_cid_put_lazy(prev);
+		prev->mm_cid = -1;
+	}
+	if (next->mm_cid_active)
+		next->last_mm_cid = next->mm_cid = mm_cid_get(rq, next->mm);
+}
+
+#else
+static inline void switch_mm_cid(struct rq *rq, struct task_struct *prev, struct task_struct *next) { }
+static inline void sched_mm_cid_migrate_from(struct task_struct *t) { }
+static inline void sched_mm_cid_migrate_to(struct rq *dst_rq, struct task_struct *t) { }
+static inline void task_tick_mm_cid(struct rq *rq, struct task_struct *curr) { }
+static inline void init_sched_mm_cid(struct task_struct *t) { }
+#endif
+
+extern u64 avg_vruntime(struct cfs_rq *cfs_rq);
+extern int entity_eligible(struct cfs_rq *cfs_rq, struct sched_entity *se);
+
+#endif /* _KERNEL_SCHED_SCHED_H */
diff --git a/kernel/sched/smp.h b/kernel/sched/smp.h
new file mode 100644
index 0000000000..21ac44428b
--- /dev/null
+++ b/kernel/sched/smp.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Scheduler internal SMP callback types and methods between the scheduler
+ * and other internal parts of the core kernel:
+ */
+
+extern void sched_ttwu_pending(void *arg);
+
+extern bool call_function_single_prep_ipi(int cpu);
+
+#ifdef CONFIG_SMP
+extern void flush_smp_call_function_queue(void);
+#else
+static inline void flush_smp_call_function_queue(void) { }
+#endif
diff --git a/kernel/sched/stats.c b/kernel/sched/stats.c
new file mode 100644
index 0000000000..857f837f52
--- /dev/null
+++ b/kernel/sched/stats.c
@@ -0,0 +1,231 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * /proc/schedstat implementation
+ */
+
+void __update_stats_wait_start(struct rq *rq, struct task_struct *p,
+			       struct sched_statistics *stats)
+{
+	u64 wait_start, prev_wait_start;
+
+	wait_start = rq_clock(rq);
+	prev_wait_start = schedstat_val(stats->wait_start);
+
+	if (p && likely(wait_start > prev_wait_start))
+		wait_start -= prev_wait_start;
+
+	__schedstat_set(stats->wait_start, wait_start);
+}
+
+void __update_stats_wait_end(struct rq *rq, struct task_struct *p,
+			     struct sched_statistics *stats)
+{
+	u64 delta = rq_clock(rq) - schedstat_val(stats->wait_start);
+
+	if (p) {
+		if (task_on_rq_migrating(p)) {
+			/*
+			 * Preserve migrating task's wait time so wait_start
+			 * time stamp can be adjusted to accumulate wait time
+			 * prior to migration.
+			 */
+			__schedstat_set(stats->wait_start, delta);
+
+			return;
+		}
+
+		trace_sched_stat_wait(p, delta);
+	}
+
+	__schedstat_set(stats->wait_max,
+			max(schedstat_val(stats->wait_max), delta));
+	__schedstat_inc(stats->wait_count);
+	__schedstat_add(stats->wait_sum, delta);
+	__schedstat_set(stats->wait_start, 0);
+}
+
+void __update_stats_enqueue_sleeper(struct rq *rq, struct task_struct *p,
+				    struct sched_statistics *stats)
+{
+	u64 sleep_start, block_start;
+
+	sleep_start = schedstat_val(stats->sleep_start);
+	block_start = schedstat_val(stats->block_start);
+
+	if (sleep_start) {
+		u64 delta = rq_clock(rq) - sleep_start;
+
+		if ((s64)delta < 0)
+			delta = 0;
+
+		if (unlikely(delta > schedstat_val(stats->sleep_max)))
+			__schedstat_set(stats->sleep_max, delta);
+
+		__schedstat_set(stats->sleep_start, 0);
+		__schedstat_add(stats->sum_sleep_runtime, delta);
+
+		if (p) {
+			account_scheduler_latency(p, delta >> 10, 1);
+			trace_sched_stat_sleep(p, delta);
+		}
+	}
+
+	if (block_start) {
+		u64 delta = rq_clock(rq) - block_start;
+
+		if ((s64)delta < 0)
+			delta = 0;
+
+		if (unlikely(delta > schedstat_val(stats->block_max)))
+			__schedstat_set(stats->block_max, delta);
+
+		__schedstat_set(stats->block_start, 0);
+		__schedstat_add(stats->sum_sleep_runtime, delta);
+		__schedstat_add(stats->sum_block_runtime, delta);
+
+		if (p) {
+			if (p->in_iowait) {
+				__schedstat_add(stats->iowait_sum, delta);
+				__schedstat_inc(stats->iowait_count);
+				trace_sched_stat_iowait(p, delta);
+			}
+
+			trace_sched_stat_blocked(p, delta);
+
+			/*
+			 * Blocking time is in units of nanosecs, so shift by
+			 * 20 to get a milliseconds-range estimation of the
+			 * amount of time that the task spent sleeping:
+			 */
+			if (unlikely(prof_on == SLEEP_PROFILING)) {
+				profile_hits(SLEEP_PROFILING,
+					     (void *)get_wchan(p),
+					     delta >> 20);
+			}
+			account_scheduler_latency(p, delta >> 10, 0);
+		}
+	}
+}
+
+/*
+ * Current schedstat API version.
+ *
+ * Bump this up when changing the output format or the meaning of an existing
+ * format, so that tools can adapt (or abort)
+ */
+#define SCHEDSTAT_VERSION 15
+
+static int show_schedstat(struct seq_file *seq, void *v)
+{
+	int cpu;
+
+	if (v == (void *)1) {
+		seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION);
+		seq_printf(seq, "timestamp %lu\n", jiffies);
+	} else {
+		struct rq *rq;
+#ifdef CONFIG_SMP
+		struct sched_domain *sd;
+		int dcount = 0;
+#endif
+		cpu = (unsigned long)(v - 2);
+		rq = cpu_rq(cpu);
+
+		/* runqueue-specific stats */
+		seq_printf(seq,
+		    "cpu%d %u 0 %u %u %u %u %llu %llu %lu",
+		    cpu, rq->yld_count,
+		    rq->sched_count, rq->sched_goidle,
+		    rq->ttwu_count, rq->ttwu_local,
+		    rq->rq_cpu_time,
+		    rq->rq_sched_info.run_delay, rq->rq_sched_info.pcount);
+
+		seq_printf(seq, "\n");
+
+#ifdef CONFIG_SMP
+		/* domain-specific stats */
+		rcu_read_lock();
+		for_each_domain(cpu, sd) {
+			enum cpu_idle_type itype;
+
+			seq_printf(seq, "domain%d %*pb", dcount++,
+				   cpumask_pr_args(sched_domain_span(sd)));
+			for (itype = CPU_IDLE; itype < CPU_MAX_IDLE_TYPES;
+					itype++) {
+				seq_printf(seq, " %u %u %u %u %u %u %u %u",
+				    sd->lb_count[itype],
+				    sd->lb_balanced[itype],
+				    sd->lb_failed[itype],
+				    sd->lb_imbalance[itype],
+				    sd->lb_gained[itype],
+				    sd->lb_hot_gained[itype],
+				    sd->lb_nobusyq[itype],
+				    sd->lb_nobusyg[itype]);
+			}
+			seq_printf(seq,
+				   " %u %u %u %u %u %u %u %u %u %u %u %u\n",
+			    sd->alb_count, sd->alb_failed, sd->alb_pushed,
+			    sd->sbe_count, sd->sbe_balanced, sd->sbe_pushed,
+			    sd->sbf_count, sd->sbf_balanced, sd->sbf_pushed,
+			    sd->ttwu_wake_remote, sd->ttwu_move_affine,
+			    sd->ttwu_move_balance);
+		}
+		rcu_read_unlock();
+#endif
+	}
+	return 0;
+}
+
+/*
+ * This iterator needs some explanation.
+ * It returns 1 for the header position.
+ * This means 2 is cpu 0.
+ * In a hotplugged system some CPUs, including cpu 0, may be missing so we have
+ * to use cpumask_* to iterate over the CPUs.
+ */
+static void *schedstat_start(struct seq_file *file, loff_t *offset)
+{
+	unsigned long n = *offset;
+
+	if (n == 0)
+		return (void *) 1;
+
+	n--;
+
+	if (n > 0)
+		n = cpumask_next(n - 1, cpu_online_mask);
+	else
+		n = cpumask_first(cpu_online_mask);
+
+	*offset = n + 1;
+
+	if (n < nr_cpu_ids)
+		return (void *)(unsigned long)(n + 2);
+
+	return NULL;
+}
+
+static void *schedstat_next(struct seq_file *file, void *data, loff_t *offset)
+{
+	(*offset)++;
+
+	return schedstat_start(file, offset);
+}
+
+static void schedstat_stop(struct seq_file *file, void *data)
+{
+}
+
+static const struct seq_operations schedstat_sops = {
+	.start = schedstat_start,
+	.next  = schedstat_next,
+	.stop  = schedstat_stop,
+	.show  = show_schedstat,
+};
+
+static int __init proc_schedstat_init(void)
+{
+	proc_create_seq("schedstat", 0, NULL, &schedstat_sops);
+	return 0;
+}
+subsys_initcall(proc_schedstat_init);
diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h
new file mode 100644
index 0000000000..38f3698f5e
--- /dev/null
+++ b/kernel/sched/stats.h
@@ -0,0 +1,296 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _KERNEL_STATS_H
+#define _KERNEL_STATS_H
+
+#ifdef CONFIG_SCHEDSTATS
+
+extern struct static_key_false sched_schedstats;
+
+/*
+ * Expects runqueue lock to be held for atomicity of update
+ */
+static inline void
+rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
+{
+	if (rq) {
+		rq->rq_sched_info.run_delay += delta;
+		rq->rq_sched_info.pcount++;
+	}
+}
+
+/*
+ * Expects runqueue lock to be held for atomicity of update
+ */
+static inline void
+rq_sched_info_depart(struct rq *rq, unsigned long long delta)
+{
+	if (rq)
+		rq->rq_cpu_time += delta;
+}
+
+static inline void
+rq_sched_info_dequeue(struct rq *rq, unsigned long long delta)
+{
+	if (rq)
+		rq->rq_sched_info.run_delay += delta;
+}
+#define   schedstat_enabled()		static_branch_unlikely(&sched_schedstats)
+#define __schedstat_inc(var)		do { var++; } while (0)
+#define   schedstat_inc(var)		do { if (schedstat_enabled()) { var++; } } while (0)
+#define __schedstat_add(var, amt)	do { var += (amt); } while (0)
+#define   schedstat_add(var, amt)	do { if (schedstat_enabled()) { var += (amt); } } while (0)
+#define __schedstat_set(var, val)	do { var = (val); } while (0)
+#define   schedstat_set(var, val)	do { if (schedstat_enabled()) { var = (val); } } while (0)
+#define   schedstat_val(var)		(var)
+#define   schedstat_val_or_zero(var)	((schedstat_enabled()) ? (var) : 0)
+
+void __update_stats_wait_start(struct rq *rq, struct task_struct *p,
+			       struct sched_statistics *stats);
+
+void __update_stats_wait_end(struct rq *rq, struct task_struct *p,
+			     struct sched_statistics *stats);
+void __update_stats_enqueue_sleeper(struct rq *rq, struct task_struct *p,
+				    struct sched_statistics *stats);
+
+static inline void
+check_schedstat_required(void)
+{
+	if (schedstat_enabled())
+		return;
+
+	/* Force schedstat enabled if a dependent tracepoint is active */
+	if (trace_sched_stat_wait_enabled()    ||
+	    trace_sched_stat_sleep_enabled()   ||
+	    trace_sched_stat_iowait_enabled()  ||
+	    trace_sched_stat_blocked_enabled() ||
+	    trace_sched_stat_runtime_enabled())
+		printk_deferred_once("Scheduler tracepoints stat_sleep, stat_iowait, stat_blocked and stat_runtime require the kernel parameter schedstats=enable or kernel.sched_schedstats=1\n");
+}
+
+#else /* !CONFIG_SCHEDSTATS: */
+
+static inline void rq_sched_info_arrive  (struct rq *rq, unsigned long long delta) { }
+static inline void rq_sched_info_dequeue(struct rq *rq, unsigned long long delta) { }
+static inline void rq_sched_info_depart  (struct rq *rq, unsigned long long delta) { }
+# define   schedstat_enabled()		0
+# define __schedstat_inc(var)		do { } while (0)
+# define   schedstat_inc(var)		do { } while (0)
+# define __schedstat_add(var, amt)	do { } while (0)
+# define   schedstat_add(var, amt)	do { } while (0)
+# define __schedstat_set(var, val)	do { } while (0)
+# define   schedstat_set(var, val)	do { } while (0)
+# define   schedstat_val(var)		0
+# define   schedstat_val_or_zero(var)	0
+
+# define __update_stats_wait_start(rq, p, stats)       do { } while (0)
+# define __update_stats_wait_end(rq, p, stats)         do { } while (0)
+# define __update_stats_enqueue_sleeper(rq, p, stats)  do { } while (0)
+# define check_schedstat_required()                    do { } while (0)
+
+#endif /* CONFIG_SCHEDSTATS */
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+struct sched_entity_stats {
+	struct sched_entity     se;
+	struct sched_statistics stats;
+} __no_randomize_layout;
+#endif
+
+static inline struct sched_statistics *
+__schedstats_from_se(struct sched_entity *se)
+{
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	if (!entity_is_task(se))
+		return &container_of(se, struct sched_entity_stats, se)->stats;
+#endif
+	return &task_of(se)->stats;
+}
+
+#ifdef CONFIG_PSI
+void psi_task_change(struct task_struct *task, int clear, int set);
+void psi_task_switch(struct task_struct *prev, struct task_struct *next,
+		     bool sleep);
+void psi_account_irqtime(struct task_struct *task, u32 delta);
+
+/*
+ * PSI tracks state that persists across sleeps, such as iowaits and
+ * memory stalls. As a result, it has to distinguish between sleeps,
+ * where a task's runnable state changes, and requeues, where a task
+ * and its state are being moved between CPUs and runqueues.
+ */
+static inline void psi_enqueue(struct task_struct *p, bool wakeup)
+{
+	int clear = 0, set = TSK_RUNNING;
+
+	if (static_branch_likely(&psi_disabled))
+		return;
+
+	if (p->in_memstall)
+		set |= TSK_MEMSTALL_RUNNING;
+
+	if (!wakeup) {
+		if (p->in_memstall)
+			set |= TSK_MEMSTALL;
+	} else {
+		if (p->in_iowait)
+			clear |= TSK_IOWAIT;
+	}
+
+	psi_task_change(p, clear, set);
+}
+
+static inline void psi_dequeue(struct task_struct *p, bool sleep)
+{
+	if (static_branch_likely(&psi_disabled))
+		return;
+
+	/*
+	 * A voluntary sleep is a dequeue followed by a task switch. To
+	 * avoid walking all ancestors twice, psi_task_switch() handles
+	 * TSK_RUNNING and TSK_IOWAIT for us when it moves TSK_ONCPU.
+	 * Do nothing here.
+	 */
+	if (sleep)
+		return;
+
+	psi_task_change(p, p->psi_flags, 0);
+}
+
+static inline void psi_ttwu_dequeue(struct task_struct *p)
+{
+	if (static_branch_likely(&psi_disabled))
+		return;
+	/*
+	 * Is the task being migrated during a wakeup? Make sure to
+	 * deregister its sleep-persistent psi states from the old
+	 * queue, and let psi_enqueue() know it has to requeue.
+	 */
+	if (unlikely(p->psi_flags)) {
+		struct rq_flags rf;
+		struct rq *rq;
+
+		rq = __task_rq_lock(p, &rf);
+		psi_task_change(p, p->psi_flags, 0);
+		__task_rq_unlock(rq, &rf);
+	}
+}
+
+static inline void psi_sched_switch(struct task_struct *prev,
+				    struct task_struct *next,
+				    bool sleep)
+{
+	if (static_branch_likely(&psi_disabled))
+		return;
+
+	psi_task_switch(prev, next, sleep);
+}
+
+#else /* CONFIG_PSI */
+static inline void psi_enqueue(struct task_struct *p, bool wakeup) {}
+static inline void psi_dequeue(struct task_struct *p, bool sleep) {}
+static inline void psi_ttwu_dequeue(struct task_struct *p) {}
+static inline void psi_sched_switch(struct task_struct *prev,
+				    struct task_struct *next,
+				    bool sleep) {}
+static inline void psi_account_irqtime(struct task_struct *task, u32 delta) {}
+#endif /* CONFIG_PSI */
+
+#ifdef CONFIG_SCHED_INFO
+/*
+ * We are interested in knowing how long it was from the *first* time a
+ * task was queued to the time that it finally hit a CPU, we call this routine
+ * from dequeue_task() to account for possible rq->clock skew across CPUs. The
+ * delta taken on each CPU would annul the skew.
+ */
+static inline void sched_info_dequeue(struct rq *rq, struct task_struct *t)
+{
+	unsigned long long delta = 0;
+
+	if (!t->sched_info.last_queued)
+		return;
+
+	delta = rq_clock(rq) - t->sched_info.last_queued;
+	t->sched_info.last_queued = 0;
+	t->sched_info.run_delay += delta;
+
+	rq_sched_info_dequeue(rq, delta);
+}
+
+/*
+ * Called when a task finally hits the CPU.  We can now calculate how
+ * long it was waiting to run.  We also note when it began so that we
+ * can keep stats on how long its timeslice is.
+ */
+static void sched_info_arrive(struct rq *rq, struct task_struct *t)
+{
+	unsigned long long now, delta = 0;
+
+	if (!t->sched_info.last_queued)
+		return;
+
+	now = rq_clock(rq);
+	delta = now - t->sched_info.last_queued;
+	t->sched_info.last_queued = 0;
+	t->sched_info.run_delay += delta;
+	t->sched_info.last_arrival = now;
+	t->sched_info.pcount++;
+
+	rq_sched_info_arrive(rq, delta);
+}
+
+/*
+ * This function is only called from enqueue_task(), but also only updates
+ * the timestamp if it is already not set.  It's assumed that
+ * sched_info_dequeue() will clear that stamp when appropriate.
+ */
+static inline void sched_info_enqueue(struct rq *rq, struct task_struct *t)
+{
+	if (!t->sched_info.last_queued)
+		t->sched_info.last_queued = rq_clock(rq);
+}
+
+/*
+ * Called when a process ceases being the active-running process involuntarily
+ * due, typically, to expiring its time slice (this may also be called when
+ * switching to the idle task).  Now we can calculate how long we ran.
+ * Also, if the process is still in the TASK_RUNNING state, call
+ * sched_info_enqueue() to mark that it has now again started waiting on
+ * the runqueue.
+ */
+static inline void sched_info_depart(struct rq *rq, struct task_struct *t)
+{
+	unsigned long long delta = rq_clock(rq) - t->sched_info.last_arrival;
+
+	rq_sched_info_depart(rq, delta);
+
+	if (task_is_running(t))
+		sched_info_enqueue(rq, t);
+}
+
+/*
+ * Called when tasks are switched involuntarily due, typically, to expiring
+ * their time slice.  (This may also be called when switching to or from
+ * the idle task.)  We are only called when prev != next.
+ */
+static inline void
+sched_info_switch(struct rq *rq, struct task_struct *prev, struct task_struct *next)
+{
+	/*
+	 * prev now departs the CPU.  It's not interesting to record
+	 * stats about how efficient we were at scheduling the idle
+	 * process, however.
+	 */
+	if (prev != rq->idle)
+		sched_info_depart(rq, prev);
+
+	if (next != rq->idle)
+		sched_info_arrive(rq, next);
+}
+
+#else /* !CONFIG_SCHED_INFO: */
+# define sched_info_enqueue(rq, t)	do { } while (0)
+# define sched_info_dequeue(rq, t)	do { } while (0)
+# define sched_info_switch(rq, t, next)	do { } while (0)
+#endif /* CONFIG_SCHED_INFO */
+
+#endif /* _KERNEL_STATS_H */
diff --git a/kernel/sched/stop_task.c b/kernel/sched/stop_task.c
new file mode 100644
index 0000000000..85590599b4
--- /dev/null
+++ b/kernel/sched/stop_task.c
@@ -0,0 +1,141 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * stop-task scheduling class.
+ *
+ * The stop task is the highest priority task in the system, it preempts
+ * everything and will be preempted by nothing.
+ *
+ * See kernel/stop_machine.c
+ */
+
+#ifdef CONFIG_SMP
+static int
+select_task_rq_stop(struct task_struct *p, int cpu, int flags)
+{
+	return task_cpu(p); /* stop tasks as never migrate */
+}
+
+static int
+balance_stop(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
+{
+	return sched_stop_runnable(rq);
+}
+#endif /* CONFIG_SMP */
+
+static void
+check_preempt_curr_stop(struct rq *rq, struct task_struct *p, int flags)
+{
+	/* we're never preempted */
+}
+
+static void set_next_task_stop(struct rq *rq, struct task_struct *stop, bool first)
+{
+	stop->se.exec_start = rq_clock_task(rq);
+}
+
+static struct task_struct *pick_task_stop(struct rq *rq)
+{
+	if (!sched_stop_runnable(rq))
+		return NULL;
+
+	return rq->stop;
+}
+
+static struct task_struct *pick_next_task_stop(struct rq *rq)
+{
+	struct task_struct *p = pick_task_stop(rq);
+
+	if (p)
+		set_next_task_stop(rq, p, true);
+
+	return p;
+}
+
+static void
+enqueue_task_stop(struct rq *rq, struct task_struct *p, int flags)
+{
+	add_nr_running(rq, 1);
+}
+
+static void
+dequeue_task_stop(struct rq *rq, struct task_struct *p, int flags)
+{
+	sub_nr_running(rq, 1);
+}
+
+static void yield_task_stop(struct rq *rq)
+{
+	BUG(); /* the stop task should never yield, its pointless. */
+}
+
+static void put_prev_task_stop(struct rq *rq, struct task_struct *prev)
+{
+	struct task_struct *curr = rq->curr;
+	u64 now, delta_exec;
+
+	now = rq_clock_task(rq);
+	delta_exec = now - curr->se.exec_start;
+	if (unlikely((s64)delta_exec < 0))
+		delta_exec = 0;
+
+	schedstat_set(curr->stats.exec_max,
+		      max(curr->stats.exec_max, delta_exec));
+
+	update_current_exec_runtime(curr, now, delta_exec);
+}
+
+/*
+ * scheduler tick hitting a task of our scheduling class.
+ *
+ * NOTE: This function can be called remotely by the tick offload that
+ * goes along full dynticks. Therefore no local assumption can be made
+ * and everything must be accessed through the @rq and @curr passed in
+ * parameters.
+ */
+static void task_tick_stop(struct rq *rq, struct task_struct *curr, int queued)
+{
+}
+
+static void switched_to_stop(struct rq *rq, struct task_struct *p)
+{
+	BUG(); /* its impossible to change to this class */
+}
+
+static void
+prio_changed_stop(struct rq *rq, struct task_struct *p, int oldprio)
+{
+	BUG(); /* how!?, what priority? */
+}
+
+static void update_curr_stop(struct rq *rq)
+{
+}
+
+/*
+ * Simple, special scheduling class for the per-CPU stop tasks:
+ */
+DEFINE_SCHED_CLASS(stop) = {
+
+	.enqueue_task		= enqueue_task_stop,
+	.dequeue_task		= dequeue_task_stop,
+	.yield_task		= yield_task_stop,
+
+	.check_preempt_curr	= check_preempt_curr_stop,
+
+	.pick_next_task		= pick_next_task_stop,
+	.put_prev_task		= put_prev_task_stop,
+	.set_next_task          = set_next_task_stop,
+
+#ifdef CONFIG_SMP
+	.balance		= balance_stop,
+	.pick_task		= pick_task_stop,
+	.select_task_rq		= select_task_rq_stop,
+	.set_cpus_allowed	= set_cpus_allowed_common,
+#endif
+
+	.task_tick		= task_tick_stop,
+
+	.prio_changed		= prio_changed_stop,
+	.switched_to		= switched_to_stop,
+	.update_curr		= update_curr_stop,
+};
diff --git a/kernel/sched/swait.c b/kernel/sched/swait.c
new file mode 100644
index 0000000000..72505cd3b6
--- /dev/null
+++ b/kernel/sched/swait.c
@@ -0,0 +1,144 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * <linux/swait.h> (simple wait queues ) implementation:
+ */
+
+void __init_swait_queue_head(struct swait_queue_head *q, const char *name,
+			     struct lock_class_key *key)
+{
+	raw_spin_lock_init(&q->lock);
+	lockdep_set_class_and_name(&q->lock, key, name);
+	INIT_LIST_HEAD(&q->task_list);
+}
+EXPORT_SYMBOL(__init_swait_queue_head);
+
+/*
+ * The thing about the wake_up_state() return value; I think we can ignore it.
+ *
+ * If for some reason it would return 0, that means the previously waiting
+ * task is already running, so it will observe condition true (or has already).
+ */
+void swake_up_locked(struct swait_queue_head *q, int wake_flags)
+{
+	struct swait_queue *curr;
+
+	if (list_empty(&q->task_list))
+		return;
+
+	curr = list_first_entry(&q->task_list, typeof(*curr), task_list);
+	try_to_wake_up(curr->task, TASK_NORMAL, wake_flags);
+	list_del_init(&curr->task_list);
+}
+EXPORT_SYMBOL(swake_up_locked);
+
+/*
+ * Wake up all waiters. This is an interface which is solely exposed for
+ * completions and not for general usage.
+ *
+ * It is intentionally different from swake_up_all() to allow usage from
+ * hard interrupt context and interrupt disabled regions.
+ */
+void swake_up_all_locked(struct swait_queue_head *q)
+{
+	while (!list_empty(&q->task_list))
+		swake_up_locked(q, 0);
+}
+
+void swake_up_one(struct swait_queue_head *q)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&q->lock, flags);
+	swake_up_locked(q, 0);
+	raw_spin_unlock_irqrestore(&q->lock, flags);
+}
+EXPORT_SYMBOL(swake_up_one);
+
+/*
+ * Does not allow usage from IRQ disabled, since we must be able to
+ * release IRQs to guarantee bounded hold time.
+ */
+void swake_up_all(struct swait_queue_head *q)
+{
+	struct swait_queue *curr;
+	LIST_HEAD(tmp);
+
+	raw_spin_lock_irq(&q->lock);
+	list_splice_init(&q->task_list, &tmp);
+	while (!list_empty(&tmp)) {
+		curr = list_first_entry(&tmp, typeof(*curr), task_list);
+
+		wake_up_state(curr->task, TASK_NORMAL);
+		list_del_init(&curr->task_list);
+
+		if (list_empty(&tmp))
+			break;
+
+		raw_spin_unlock_irq(&q->lock);
+		raw_spin_lock_irq(&q->lock);
+	}
+	raw_spin_unlock_irq(&q->lock);
+}
+EXPORT_SYMBOL(swake_up_all);
+
+void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait)
+{
+	wait->task = current;
+	if (list_empty(&wait->task_list))
+		list_add_tail(&wait->task_list, &q->task_list);
+}
+
+void prepare_to_swait_exclusive(struct swait_queue_head *q, struct swait_queue *wait, int state)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&q->lock, flags);
+	__prepare_to_swait(q, wait);
+	set_current_state(state);
+	raw_spin_unlock_irqrestore(&q->lock, flags);
+}
+EXPORT_SYMBOL(prepare_to_swait_exclusive);
+
+long prepare_to_swait_event(struct swait_queue_head *q, struct swait_queue *wait, int state)
+{
+	unsigned long flags;
+	long ret = 0;
+
+	raw_spin_lock_irqsave(&q->lock, flags);
+	if (signal_pending_state(state, current)) {
+		/*
+		 * See prepare_to_wait_event(). TL;DR, subsequent swake_up_one()
+		 * must not see us.
+		 */
+		list_del_init(&wait->task_list);
+		ret = -ERESTARTSYS;
+	} else {
+		__prepare_to_swait(q, wait);
+		set_current_state(state);
+	}
+	raw_spin_unlock_irqrestore(&q->lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(prepare_to_swait_event);
+
+void __finish_swait(struct swait_queue_head *q, struct swait_queue *wait)
+{
+	__set_current_state(TASK_RUNNING);
+	if (!list_empty(&wait->task_list))
+		list_del_init(&wait->task_list);
+}
+
+void finish_swait(struct swait_queue_head *q, struct swait_queue *wait)
+{
+	unsigned long flags;
+
+	__set_current_state(TASK_RUNNING);
+
+	if (!list_empty_careful(&wait->task_list)) {
+		raw_spin_lock_irqsave(&q->lock, flags);
+		list_del_init(&wait->task_list);
+		raw_spin_unlock_irqrestore(&q->lock, flags);
+	}
+}
+EXPORT_SYMBOL(finish_swait);
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
new file mode 100644
index 0000000000..423d089479
--- /dev/null
+++ b/kernel/sched/topology.c
@@ -0,0 +1,2760 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Scheduler topology setup/handling methods
+ */
+
+#include <linux/bsearch.h>
+
+DEFINE_MUTEX(sched_domains_mutex);
+
+/* Protected by sched_domains_mutex: */
+static cpumask_var_t sched_domains_tmpmask;
+static cpumask_var_t sched_domains_tmpmask2;
+
+#ifdef CONFIG_SCHED_DEBUG
+
+static int __init sched_debug_setup(char *str)
+{
+	sched_debug_verbose = true;
+
+	return 0;
+}
+early_param("sched_verbose", sched_debug_setup);
+
+static inline bool sched_debug(void)
+{
+	return sched_debug_verbose;
+}
+
+#define SD_FLAG(_name, mflags) [__##_name] = { .meta_flags = mflags, .name = #_name },
+const struct sd_flag_debug sd_flag_debug[] = {
+#include <linux/sched/sd_flags.h>
+};
+#undef SD_FLAG
+
+static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
+				  struct cpumask *groupmask)
+{
+	struct sched_group *group = sd->groups;
+	unsigned long flags = sd->flags;
+	unsigned int idx;
+
+	cpumask_clear(groupmask);
+
+	printk(KERN_DEBUG "%*s domain-%d: ", level, "", level);
+	printk(KERN_CONT "span=%*pbl level=%s\n",
+	       cpumask_pr_args(sched_domain_span(sd)), sd->name);
+
+	if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
+		printk(KERN_ERR "ERROR: domain->span does not contain CPU%d\n", cpu);
+	}
+	if (group && !cpumask_test_cpu(cpu, sched_group_span(group))) {
+		printk(KERN_ERR "ERROR: domain->groups does not contain CPU%d\n", cpu);
+	}
+
+	for_each_set_bit(idx, &flags, __SD_FLAG_CNT) {
+		unsigned int flag = BIT(idx);
+		unsigned int meta_flags = sd_flag_debug[idx].meta_flags;
+
+		if ((meta_flags & SDF_SHARED_CHILD) && sd->child &&
+		    !(sd->child->flags & flag))
+			printk(KERN_ERR "ERROR: flag %s set here but not in child\n",
+			       sd_flag_debug[idx].name);
+
+		if ((meta_flags & SDF_SHARED_PARENT) && sd->parent &&
+		    !(sd->parent->flags & flag))
+			printk(KERN_ERR "ERROR: flag %s set here but not in parent\n",
+			       sd_flag_debug[idx].name);
+	}
+
+	printk(KERN_DEBUG "%*s groups:", level + 1, "");
+	do {
+		if (!group) {
+			printk("\n");
+			printk(KERN_ERR "ERROR: group is NULL\n");
+			break;
+		}
+
+		if (cpumask_empty(sched_group_span(group))) {
+			printk(KERN_CONT "\n");
+			printk(KERN_ERR "ERROR: empty group\n");
+			break;
+		}
+
+		if (!(sd->flags & SD_OVERLAP) &&
+		    cpumask_intersects(groupmask, sched_group_span(group))) {
+			printk(KERN_CONT "\n");
+			printk(KERN_ERR "ERROR: repeated CPUs\n");
+			break;
+		}
+
+		cpumask_or(groupmask, groupmask, sched_group_span(group));
+
+		printk(KERN_CONT " %d:{ span=%*pbl",
+				group->sgc->id,
+				cpumask_pr_args(sched_group_span(group)));
+
+		if ((sd->flags & SD_OVERLAP) &&
+		    !cpumask_equal(group_balance_mask(group), sched_group_span(group))) {
+			printk(KERN_CONT " mask=%*pbl",
+				cpumask_pr_args(group_balance_mask(group)));
+		}
+
+		if (group->sgc->capacity != SCHED_CAPACITY_SCALE)
+			printk(KERN_CONT " cap=%lu", group->sgc->capacity);
+
+		if (group == sd->groups && sd->child &&
+		    !cpumask_equal(sched_domain_span(sd->child),
+				   sched_group_span(group))) {
+			printk(KERN_ERR "ERROR: domain->groups does not match domain->child\n");
+		}
+
+		printk(KERN_CONT " }");
+
+		group = group->next;
+
+		if (group != sd->groups)
+			printk(KERN_CONT ",");
+
+	} while (group != sd->groups);
+	printk(KERN_CONT "\n");
+
+	if (!cpumask_equal(sched_domain_span(sd), groupmask))
+		printk(KERN_ERR "ERROR: groups don't span domain->span\n");
+
+	if (sd->parent &&
+	    !cpumask_subset(groupmask, sched_domain_span(sd->parent)))
+		printk(KERN_ERR "ERROR: parent span is not a superset of domain->span\n");
+	return 0;
+}
+
+static void sched_domain_debug(struct sched_domain *sd, int cpu)
+{
+	int level = 0;
+
+	if (!sched_debug_verbose)
+		return;
+
+	if (!sd) {
+		printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
+		return;
+	}
+
+	printk(KERN_DEBUG "CPU%d attaching sched-domain(s):\n", cpu);
+
+	for (;;) {
+		if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask))
+			break;
+		level++;
+		sd = sd->parent;
+		if (!sd)
+			break;
+	}
+}
+#else /* !CONFIG_SCHED_DEBUG */
+
+# define sched_debug_verbose 0
+# define sched_domain_debug(sd, cpu) do { } while (0)
+static inline bool sched_debug(void)
+{
+	return false;
+}
+#endif /* CONFIG_SCHED_DEBUG */
+
+/* Generate a mask of SD flags with the SDF_NEEDS_GROUPS metaflag */
+#define SD_FLAG(name, mflags) (name * !!((mflags) & SDF_NEEDS_GROUPS)) |
+static const unsigned int SD_DEGENERATE_GROUPS_MASK =
+#include <linux/sched/sd_flags.h>
+0;
+#undef SD_FLAG
+
+static int sd_degenerate(struct sched_domain *sd)
+{
+	if (cpumask_weight(sched_domain_span(sd)) == 1)
+		return 1;
+
+	/* Following flags need at least 2 groups */
+	if ((sd->flags & SD_DEGENERATE_GROUPS_MASK) &&
+	    (sd->groups != sd->groups->next))
+		return 0;
+
+	/* Following flags don't use groups */
+	if (sd->flags & (SD_WAKE_AFFINE))
+		return 0;
+
+	return 1;
+}
+
+static int
+sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
+{
+	unsigned long cflags = sd->flags, pflags = parent->flags;
+
+	if (sd_degenerate(parent))
+		return 1;
+
+	if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
+		return 0;
+
+	/* Flags needing groups don't count if only 1 group in parent */
+	if (parent->groups == parent->groups->next)
+		pflags &= ~SD_DEGENERATE_GROUPS_MASK;
+
+	if (~cflags & pflags)
+		return 0;
+
+	return 1;
+}
+
+#if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
+DEFINE_STATIC_KEY_FALSE(sched_energy_present);
+static unsigned int sysctl_sched_energy_aware = 1;
+static DEFINE_MUTEX(sched_energy_mutex);
+static bool sched_energy_update;
+
+void rebuild_sched_domains_energy(void)
+{
+	mutex_lock(&sched_energy_mutex);
+	sched_energy_update = true;
+	rebuild_sched_domains();
+	sched_energy_update = false;
+	mutex_unlock(&sched_energy_mutex);
+}
+
+#ifdef CONFIG_PROC_SYSCTL
+static int sched_energy_aware_handler(struct ctl_table *table, int write,
+		void *buffer, size_t *lenp, loff_t *ppos)
+{
+	int ret, state;
+
+	if (write && !capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+	if (!ret && write) {
+		state = static_branch_unlikely(&sched_energy_present);
+		if (state != sysctl_sched_energy_aware)
+			rebuild_sched_domains_energy();
+	}
+
+	return ret;
+}
+
+static struct ctl_table sched_energy_aware_sysctls[] = {
+	{
+		.procname       = "sched_energy_aware",
+		.data           = &sysctl_sched_energy_aware,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = sched_energy_aware_handler,
+		.extra1         = SYSCTL_ZERO,
+		.extra2         = SYSCTL_ONE,
+	},
+	{}
+};
+
+static int __init sched_energy_aware_sysctl_init(void)
+{
+	register_sysctl_init("kernel", sched_energy_aware_sysctls);
+	return 0;
+}
+
+late_initcall(sched_energy_aware_sysctl_init);
+#endif
+
+static void free_pd(struct perf_domain *pd)
+{
+	struct perf_domain *tmp;
+
+	while (pd) {
+		tmp = pd->next;
+		kfree(pd);
+		pd = tmp;
+	}
+}
+
+static struct perf_domain *find_pd(struct perf_domain *pd, int cpu)
+{
+	while (pd) {
+		if (cpumask_test_cpu(cpu, perf_domain_span(pd)))
+			return pd;
+		pd = pd->next;
+	}
+
+	return NULL;
+}
+
+static struct perf_domain *pd_init(int cpu)
+{
+	struct em_perf_domain *obj = em_cpu_get(cpu);
+	struct perf_domain *pd;
+
+	if (!obj) {
+		if (sched_debug())
+			pr_info("%s: no EM found for CPU%d\n", __func__, cpu);
+		return NULL;
+	}
+
+	pd = kzalloc(sizeof(*pd), GFP_KERNEL);
+	if (!pd)
+		return NULL;
+	pd->em_pd = obj;
+
+	return pd;
+}
+
+static void perf_domain_debug(const struct cpumask *cpu_map,
+						struct perf_domain *pd)
+{
+	if (!sched_debug() || !pd)
+		return;
+
+	printk(KERN_DEBUG "root_domain %*pbl:", cpumask_pr_args(cpu_map));
+
+	while (pd) {
+		printk(KERN_CONT " pd%d:{ cpus=%*pbl nr_pstate=%d }",
+				cpumask_first(perf_domain_span(pd)),
+				cpumask_pr_args(perf_domain_span(pd)),
+				em_pd_nr_perf_states(pd->em_pd));
+		pd = pd->next;
+	}
+
+	printk(KERN_CONT "\n");
+}
+
+static void destroy_perf_domain_rcu(struct rcu_head *rp)
+{
+	struct perf_domain *pd;
+
+	pd = container_of(rp, struct perf_domain, rcu);
+	free_pd(pd);
+}
+
+static void sched_energy_set(bool has_eas)
+{
+	if (!has_eas && static_branch_unlikely(&sched_energy_present)) {
+		if (sched_debug())
+			pr_info("%s: stopping EAS\n", __func__);
+		static_branch_disable_cpuslocked(&sched_energy_present);
+	} else if (has_eas && !static_branch_unlikely(&sched_energy_present)) {
+		if (sched_debug())
+			pr_info("%s: starting EAS\n", __func__);
+		static_branch_enable_cpuslocked(&sched_energy_present);
+	}
+}
+
+/*
+ * EAS can be used on a root domain if it meets all the following conditions:
+ *    1. an Energy Model (EM) is available;
+ *    2. the SD_ASYM_CPUCAPACITY flag is set in the sched_domain hierarchy.
+ *    3. no SMT is detected.
+ *    4. the EM complexity is low enough to keep scheduling overheads low;
+ *    5. schedutil is driving the frequency of all CPUs of the rd;
+ *    6. frequency invariance support is present;
+ *
+ * The complexity of the Energy Model is defined as:
+ *
+ *              C = nr_pd * (nr_cpus + nr_ps)
+ *
+ * with parameters defined as:
+ *  - nr_pd:    the number of performance domains
+ *  - nr_cpus:  the number of CPUs
+ *  - nr_ps:    the sum of the number of performance states of all performance
+ *              domains (for example, on a system with 2 performance domains,
+ *              with 10 performance states each, nr_ps = 2 * 10 = 20).
+ *
+ * It is generally not a good idea to use such a model in the wake-up path on
+ * very complex platforms because of the associated scheduling overheads. The
+ * arbitrary constraint below prevents that. It makes EAS usable up to 16 CPUs
+ * with per-CPU DVFS and less than 8 performance states each, for example.
+ */
+#define EM_MAX_COMPLEXITY 2048
+
+extern struct cpufreq_governor schedutil_gov;
+static bool build_perf_domains(const struct cpumask *cpu_map)
+{
+	int i, nr_pd = 0, nr_ps = 0, nr_cpus = cpumask_weight(cpu_map);
+	struct perf_domain *pd = NULL, *tmp;
+	int cpu = cpumask_first(cpu_map);
+	struct root_domain *rd = cpu_rq(cpu)->rd;
+	struct cpufreq_policy *policy;
+	struct cpufreq_governor *gov;
+
+	if (!sysctl_sched_energy_aware)
+		goto free;
+
+	/* EAS is enabled for asymmetric CPU capacity topologies. */
+	if (!per_cpu(sd_asym_cpucapacity, cpu)) {
+		if (sched_debug()) {
+			pr_info("rd %*pbl: CPUs do not have asymmetric capacities\n",
+					cpumask_pr_args(cpu_map));
+		}
+		goto free;
+	}
+
+	/* EAS definitely does *not* handle SMT */
+	if (sched_smt_active()) {
+		pr_warn("rd %*pbl: Disabling EAS, SMT is not supported\n",
+			cpumask_pr_args(cpu_map));
+		goto free;
+	}
+
+	if (!arch_scale_freq_invariant()) {
+		if (sched_debug()) {
+			pr_warn("rd %*pbl: Disabling EAS: frequency-invariant load tracking not yet supported",
+				cpumask_pr_args(cpu_map));
+		}
+		goto free;
+	}
+
+	for_each_cpu(i, cpu_map) {
+		/* Skip already covered CPUs. */
+		if (find_pd(pd, i))
+			continue;
+
+		/* Do not attempt EAS if schedutil is not being used. */
+		policy = cpufreq_cpu_get(i);
+		if (!policy)
+			goto free;
+		gov = policy->governor;
+		cpufreq_cpu_put(policy);
+		if (gov != &schedutil_gov) {
+			if (rd->pd)
+				pr_warn("rd %*pbl: Disabling EAS, schedutil is mandatory\n",
+						cpumask_pr_args(cpu_map));
+			goto free;
+		}
+
+		/* Create the new pd and add it to the local list. */
+		tmp = pd_init(i);
+		if (!tmp)
+			goto free;
+		tmp->next = pd;
+		pd = tmp;
+
+		/*
+		 * Count performance domains and performance states for the
+		 * complexity check.
+		 */
+		nr_pd++;
+		nr_ps += em_pd_nr_perf_states(pd->em_pd);
+	}
+
+	/* Bail out if the Energy Model complexity is too high. */
+	if (nr_pd * (nr_ps + nr_cpus) > EM_MAX_COMPLEXITY) {
+		WARN(1, "rd %*pbl: Failed to start EAS, EM complexity is too high\n",
+						cpumask_pr_args(cpu_map));
+		goto free;
+	}
+
+	perf_domain_debug(cpu_map, pd);
+
+	/* Attach the new list of performance domains to the root domain. */
+	tmp = rd->pd;
+	rcu_assign_pointer(rd->pd, pd);
+	if (tmp)
+		call_rcu(&tmp->rcu, destroy_perf_domain_rcu);
+
+	return !!pd;
+
+free:
+	free_pd(pd);
+	tmp = rd->pd;
+	rcu_assign_pointer(rd->pd, NULL);
+	if (tmp)
+		call_rcu(&tmp->rcu, destroy_perf_domain_rcu);
+
+	return false;
+}
+#else
+static void free_pd(struct perf_domain *pd) { }
+#endif /* CONFIG_ENERGY_MODEL && CONFIG_CPU_FREQ_GOV_SCHEDUTIL*/
+
+static void free_rootdomain(struct rcu_head *rcu)
+{
+	struct root_domain *rd = container_of(rcu, struct root_domain, rcu);
+
+	cpupri_cleanup(&rd->cpupri);
+	cpudl_cleanup(&rd->cpudl);
+	free_cpumask_var(rd->dlo_mask);
+	free_cpumask_var(rd->rto_mask);
+	free_cpumask_var(rd->online);
+	free_cpumask_var(rd->span);
+	free_pd(rd->pd);
+	kfree(rd);
+}
+
+void rq_attach_root(struct rq *rq, struct root_domain *rd)
+{
+	struct root_domain *old_rd = NULL;
+	struct rq_flags rf;
+
+	rq_lock_irqsave(rq, &rf);
+
+	if (rq->rd) {
+		old_rd = rq->rd;
+
+		if (cpumask_test_cpu(rq->cpu, old_rd->online))
+			set_rq_offline(rq);
+
+		cpumask_clear_cpu(rq->cpu, old_rd->span);
+
+		/*
+		 * If we dont want to free the old_rd yet then
+		 * set old_rd to NULL to skip the freeing later
+		 * in this function:
+		 */
+		if (!atomic_dec_and_test(&old_rd->refcount))
+			old_rd = NULL;
+	}
+
+	atomic_inc(&rd->refcount);
+	rq->rd = rd;
+
+	cpumask_set_cpu(rq->cpu, rd->span);
+	if (cpumask_test_cpu(rq->cpu, cpu_active_mask))
+		set_rq_online(rq);
+
+	rq_unlock_irqrestore(rq, &rf);
+
+	if (old_rd)
+		call_rcu(&old_rd->rcu, free_rootdomain);
+}
+
+void sched_get_rd(struct root_domain *rd)
+{
+	atomic_inc(&rd->refcount);
+}
+
+void sched_put_rd(struct root_domain *rd)
+{
+	if (!atomic_dec_and_test(&rd->refcount))
+		return;
+
+	call_rcu(&rd->rcu, free_rootdomain);
+}
+
+static int init_rootdomain(struct root_domain *rd)
+{
+	if (!zalloc_cpumask_var(&rd->span, GFP_KERNEL))
+		goto out;
+	if (!zalloc_cpumask_var(&rd->online, GFP_KERNEL))
+		goto free_span;
+	if (!zalloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL))
+		goto free_online;
+	if (!zalloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
+		goto free_dlo_mask;
+
+#ifdef HAVE_RT_PUSH_IPI
+	rd->rto_cpu = -1;
+	raw_spin_lock_init(&rd->rto_lock);
+	rd->rto_push_work = IRQ_WORK_INIT_HARD(rto_push_irq_work_func);
+#endif
+
+	rd->visit_gen = 0;
+	init_dl_bw(&rd->dl_bw);
+	if (cpudl_init(&rd->cpudl) != 0)
+		goto free_rto_mask;
+
+	if (cpupri_init(&rd->cpupri) != 0)
+		goto free_cpudl;
+	return 0;
+
+free_cpudl:
+	cpudl_cleanup(&rd->cpudl);
+free_rto_mask:
+	free_cpumask_var(rd->rto_mask);
+free_dlo_mask:
+	free_cpumask_var(rd->dlo_mask);
+free_online:
+	free_cpumask_var(rd->online);
+free_span:
+	free_cpumask_var(rd->span);
+out:
+	return -ENOMEM;
+}
+
+/*
+ * By default the system creates a single root-domain with all CPUs as
+ * members (mimicking the global state we have today).
+ */
+struct root_domain def_root_domain;
+
+void __init init_defrootdomain(void)
+{
+	init_rootdomain(&def_root_domain);
+
+	atomic_set(&def_root_domain.refcount, 1);
+}
+
+static struct root_domain *alloc_rootdomain(void)
+{
+	struct root_domain *rd;
+
+	rd = kzalloc(sizeof(*rd), GFP_KERNEL);
+	if (!rd)
+		return NULL;
+
+	if (init_rootdomain(rd) != 0) {
+		kfree(rd);
+		return NULL;
+	}
+
+	return rd;
+}
+
+static void free_sched_groups(struct sched_group *sg, int free_sgc)
+{
+	struct sched_group *tmp, *first;
+
+	if (!sg)
+		return;
+
+	first = sg;
+	do {
+		tmp = sg->next;
+
+		if (free_sgc && atomic_dec_and_test(&sg->sgc->ref))
+			kfree(sg->sgc);
+
+		if (atomic_dec_and_test(&sg->ref))
+			kfree(sg);
+		sg = tmp;
+	} while (sg != first);
+}
+
+static void destroy_sched_domain(struct sched_domain *sd)
+{
+	/*
+	 * A normal sched domain may have multiple group references, an
+	 * overlapping domain, having private groups, only one.  Iterate,
+	 * dropping group/capacity references, freeing where none remain.
+	 */
+	free_sched_groups(sd->groups, 1);
+
+	if (sd->shared && atomic_dec_and_test(&sd->shared->ref))
+		kfree(sd->shared);
+	kfree(sd);
+}
+
+static void destroy_sched_domains_rcu(struct rcu_head *rcu)
+{
+	struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu);
+
+	while (sd) {
+		struct sched_domain *parent = sd->parent;
+		destroy_sched_domain(sd);
+		sd = parent;
+	}
+}
+
+static void destroy_sched_domains(struct sched_domain *sd)
+{
+	if (sd)
+		call_rcu(&sd->rcu, destroy_sched_domains_rcu);
+}
+
+/*
+ * Keep a special pointer to the highest sched_domain that has
+ * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
+ * allows us to avoid some pointer chasing select_idle_sibling().
+ *
+ * Also keep a unique ID per domain (we use the first CPU number in
+ * the cpumask of the domain), this allows us to quickly tell if
+ * two CPUs are in the same cache domain, see cpus_share_cache().
+ */
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_llc);
+DEFINE_PER_CPU(int, sd_llc_size);
+DEFINE_PER_CPU(int, sd_llc_id);
+DEFINE_PER_CPU(struct sched_domain_shared __rcu *, sd_llc_shared);
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_numa);
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing);
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_cpucapacity);
+DEFINE_STATIC_KEY_FALSE(sched_asym_cpucapacity);
+
+static void update_top_cache_domain(int cpu)
+{
+	struct sched_domain_shared *sds = NULL;
+	struct sched_domain *sd;
+	int id = cpu;
+	int size = 1;
+
+	sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES);
+	if (sd) {
+		id = cpumask_first(sched_domain_span(sd));
+		size = cpumask_weight(sched_domain_span(sd));
+		sds = sd->shared;
+	}
+
+	rcu_assign_pointer(per_cpu(sd_llc, cpu), sd);
+	per_cpu(sd_llc_size, cpu) = size;
+	per_cpu(sd_llc_id, cpu) = id;
+	rcu_assign_pointer(per_cpu(sd_llc_shared, cpu), sds);
+
+	sd = lowest_flag_domain(cpu, SD_NUMA);
+	rcu_assign_pointer(per_cpu(sd_numa, cpu), sd);
+
+	sd = highest_flag_domain(cpu, SD_ASYM_PACKING);
+	rcu_assign_pointer(per_cpu(sd_asym_packing, cpu), sd);
+
+	sd = lowest_flag_domain(cpu, SD_ASYM_CPUCAPACITY_FULL);
+	rcu_assign_pointer(per_cpu(sd_asym_cpucapacity, cpu), sd);
+}
+
+/*
+ * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
+ * hold the hotplug lock.
+ */
+static void
+cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	struct sched_domain *tmp;
+
+	/* Remove the sched domains which do not contribute to scheduling. */
+	for (tmp = sd; tmp; ) {
+		struct sched_domain *parent = tmp->parent;
+		if (!parent)
+			break;
+
+		if (sd_parent_degenerate(tmp, parent)) {
+			tmp->parent = parent->parent;
+
+			if (parent->parent) {
+				parent->parent->child = tmp;
+				parent->parent->groups->flags = tmp->flags;
+			}
+
+			/*
+			 * Transfer SD_PREFER_SIBLING down in case of a
+			 * degenerate parent; the spans match for this
+			 * so the property transfers.
+			 */
+			if (parent->flags & SD_PREFER_SIBLING)
+				tmp->flags |= SD_PREFER_SIBLING;
+			destroy_sched_domain(parent);
+		} else
+			tmp = tmp->parent;
+	}
+
+	if (sd && sd_degenerate(sd)) {
+		tmp = sd;
+		sd = sd->parent;
+		destroy_sched_domain(tmp);
+		if (sd) {
+			struct sched_group *sg = sd->groups;
+
+			/*
+			 * sched groups hold the flags of the child sched
+			 * domain for convenience. Clear such flags since
+			 * the child is being destroyed.
+			 */
+			do {
+				sg->flags = 0;
+			} while (sg != sd->groups);
+
+			sd->child = NULL;
+		}
+	}
+
+	sched_domain_debug(sd, cpu);
+
+	rq_attach_root(rq, rd);
+	tmp = rq->sd;
+	rcu_assign_pointer(rq->sd, sd);
+	dirty_sched_domain_sysctl(cpu);
+	destroy_sched_domains(tmp);
+
+	update_top_cache_domain(cpu);
+}
+
+struct s_data {
+	struct sched_domain * __percpu *sd;
+	struct root_domain	*rd;
+};
+
+enum s_alloc {
+	sa_rootdomain,
+	sa_sd,
+	sa_sd_storage,
+	sa_none,
+};
+
+/*
+ * Return the canonical balance CPU for this group, this is the first CPU
+ * of this group that's also in the balance mask.
+ *
+ * The balance mask are all those CPUs that could actually end up at this
+ * group. See build_balance_mask().
+ *
+ * Also see should_we_balance().
+ */
+int group_balance_cpu(struct sched_group *sg)
+{
+	return cpumask_first(group_balance_mask(sg));
+}
+
+
+/*
+ * NUMA topology (first read the regular topology blurb below)
+ *
+ * Given a node-distance table, for example:
+ *
+ *   node   0   1   2   3
+ *     0:  10  20  30  20
+ *     1:  20  10  20  30
+ *     2:  30  20  10  20
+ *     3:  20  30  20  10
+ *
+ * which represents a 4 node ring topology like:
+ *
+ *   0 ----- 1
+ *   |       |
+ *   |       |
+ *   |       |
+ *   3 ----- 2
+ *
+ * We want to construct domains and groups to represent this. The way we go
+ * about doing this is to build the domains on 'hops'. For each NUMA level we
+ * construct the mask of all nodes reachable in @level hops.
+ *
+ * For the above NUMA topology that gives 3 levels:
+ *
+ * NUMA-2	0-3		0-3		0-3		0-3
+ *  groups:	{0-1,3},{1-3}	{0-2},{0,2-3}	{1-3},{0-1,3}	{0,2-3},{0-2}
+ *
+ * NUMA-1	0-1,3		0-2		1-3		0,2-3
+ *  groups:	{0},{1},{3}	{0},{1},{2}	{1},{2},{3}	{0},{2},{3}
+ *
+ * NUMA-0	0		1		2		3
+ *
+ *
+ * As can be seen; things don't nicely line up as with the regular topology.
+ * When we iterate a domain in child domain chunks some nodes can be
+ * represented multiple times -- hence the "overlap" naming for this part of
+ * the topology.
+ *
+ * In order to minimize this overlap, we only build enough groups to cover the
+ * domain. For instance Node-0 NUMA-2 would only get groups: 0-1,3 and 1-3.
+ *
+ * Because:
+ *
+ *  - the first group of each domain is its child domain; this
+ *    gets us the first 0-1,3
+ *  - the only uncovered node is 2, who's child domain is 1-3.
+ *
+ * However, because of the overlap, computing a unique CPU for each group is
+ * more complicated. Consider for instance the groups of NODE-1 NUMA-2, both
+ * groups include the CPUs of Node-0, while those CPUs would not in fact ever
+ * end up at those groups (they would end up in group: 0-1,3).
+ *
+ * To correct this we have to introduce the group balance mask. This mask
+ * will contain those CPUs in the group that can reach this group given the
+ * (child) domain tree.
+ *
+ * With this we can once again compute balance_cpu and sched_group_capacity
+ * relations.
+ *
+ * XXX include words on how balance_cpu is unique and therefore can be
+ * used for sched_group_capacity links.
+ *
+ *
+ * Another 'interesting' topology is:
+ *
+ *   node   0   1   2   3
+ *     0:  10  20  20  30
+ *     1:  20  10  20  20
+ *     2:  20  20  10  20
+ *     3:  30  20  20  10
+ *
+ * Which looks a little like:
+ *
+ *   0 ----- 1
+ *   |     / |
+ *   |   /   |
+ *   | /     |
+ *   2 ----- 3
+ *
+ * This topology is asymmetric, nodes 1,2 are fully connected, but nodes 0,3
+ * are not.
+ *
+ * This leads to a few particularly weird cases where the sched_domain's are
+ * not of the same number for each CPU. Consider:
+ *
+ * NUMA-2	0-3						0-3
+ *  groups:	{0-2},{1-3}					{1-3},{0-2}
+ *
+ * NUMA-1	0-2		0-3		0-3		1-3
+ *
+ * NUMA-0	0		1		2		3
+ *
+ */
+
+
+/*
+ * Build the balance mask; it contains only those CPUs that can arrive at this
+ * group and should be considered to continue balancing.
+ *
+ * We do this during the group creation pass, therefore the group information
+ * isn't complete yet, however since each group represents a (child) domain we
+ * can fully construct this using the sched_domain bits (which are already
+ * complete).
+ */
+static void
+build_balance_mask(struct sched_domain *sd, struct sched_group *sg, struct cpumask *mask)
+{
+	const struct cpumask *sg_span = sched_group_span(sg);
+	struct sd_data *sdd = sd->private;
+	struct sched_domain *sibling;
+	int i;
+
+	cpumask_clear(mask);
+
+	for_each_cpu(i, sg_span) {
+		sibling = *per_cpu_ptr(sdd->sd, i);
+
+		/*
+		 * Can happen in the asymmetric case, where these siblings are
+		 * unused. The mask will not be empty because those CPUs that
+		 * do have the top domain _should_ span the domain.
+		 */
+		if (!sibling->child)
+			continue;
+
+		/* If we would not end up here, we can't continue from here */
+		if (!cpumask_equal(sg_span, sched_domain_span(sibling->child)))
+			continue;
+
+		cpumask_set_cpu(i, mask);
+	}
+
+	/* We must not have empty masks here */
+	WARN_ON_ONCE(cpumask_empty(mask));
+}
+
+/*
+ * XXX: This creates per-node group entries; since the load-balancer will
+ * immediately access remote memory to construct this group's load-balance
+ * statistics having the groups node local is of dubious benefit.
+ */
+static struct sched_group *
+build_group_from_child_sched_domain(struct sched_domain *sd, int cpu)
+{
+	struct sched_group *sg;
+	struct cpumask *sg_span;
+
+	sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
+			GFP_KERNEL, cpu_to_node(cpu));
+
+	if (!sg)
+		return NULL;
+
+	sg_span = sched_group_span(sg);
+	if (sd->child) {
+		cpumask_copy(sg_span, sched_domain_span(sd->child));
+		sg->flags = sd->child->flags;
+	} else {
+		cpumask_copy(sg_span, sched_domain_span(sd));
+	}
+
+	atomic_inc(&sg->ref);
+	return sg;
+}
+
+static void init_overlap_sched_group(struct sched_domain *sd,
+				     struct sched_group *sg)
+{
+	struct cpumask *mask = sched_domains_tmpmask2;
+	struct sd_data *sdd = sd->private;
+	struct cpumask *sg_span;
+	int cpu;
+
+	build_balance_mask(sd, sg, mask);
+	cpu = cpumask_first(mask);
+
+	sg->sgc = *per_cpu_ptr(sdd->sgc, cpu);
+	if (atomic_inc_return(&sg->sgc->ref) == 1)
+		cpumask_copy(group_balance_mask(sg), mask);
+	else
+		WARN_ON_ONCE(!cpumask_equal(group_balance_mask(sg), mask));
+
+	/*
+	 * Initialize sgc->capacity such that even if we mess up the
+	 * domains and no possible iteration will get us here, we won't
+	 * die on a /0 trap.
+	 */
+	sg_span = sched_group_span(sg);
+	sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sg_span);
+	sg->sgc->min_capacity = SCHED_CAPACITY_SCALE;
+	sg->sgc->max_capacity = SCHED_CAPACITY_SCALE;
+}
+
+static struct sched_domain *
+find_descended_sibling(struct sched_domain *sd, struct sched_domain *sibling)
+{
+	/*
+	 * The proper descendant would be the one whose child won't span out
+	 * of sd
+	 */
+	while (sibling->child &&
+	       !cpumask_subset(sched_domain_span(sibling->child),
+			       sched_domain_span(sd)))
+		sibling = sibling->child;
+
+	/*
+	 * As we are referencing sgc across different topology level, we need
+	 * to go down to skip those sched_domains which don't contribute to
+	 * scheduling because they will be degenerated in cpu_attach_domain
+	 */
+	while (sibling->child &&
+	       cpumask_equal(sched_domain_span(sibling->child),
+			     sched_domain_span(sibling)))
+		sibling = sibling->child;
+
+	return sibling;
+}
+
+static int
+build_overlap_sched_groups(struct sched_domain *sd, int cpu)
+{
+	struct sched_group *first = NULL, *last = NULL, *sg;
+	const struct cpumask *span = sched_domain_span(sd);
+	struct cpumask *covered = sched_domains_tmpmask;
+	struct sd_data *sdd = sd->private;
+	struct sched_domain *sibling;
+	int i;
+
+	cpumask_clear(covered);
+
+	for_each_cpu_wrap(i, span, cpu) {
+		struct cpumask *sg_span;
+
+		if (cpumask_test_cpu(i, covered))
+			continue;
+
+		sibling = *per_cpu_ptr(sdd->sd, i);
+
+		/*
+		 * Asymmetric node setups can result in situations where the
+		 * domain tree is of unequal depth, make sure to skip domains
+		 * that already cover the entire range.
+		 *
+		 * In that case build_sched_domains() will have terminated the
+		 * iteration early and our sibling sd spans will be empty.
+		 * Domains should always include the CPU they're built on, so
+		 * check that.
+		 */
+		if (!cpumask_test_cpu(i, sched_domain_span(sibling)))
+			continue;
+
+		/*
+		 * Usually we build sched_group by sibling's child sched_domain
+		 * But for machines whose NUMA diameter are 3 or above, we move
+		 * to build sched_group by sibling's proper descendant's child
+		 * domain because sibling's child sched_domain will span out of
+		 * the sched_domain being built as below.
+		 *
+		 * Smallest diameter=3 topology is:
+		 *
+		 *   node   0   1   2   3
+		 *     0:  10  20  30  40
+		 *     1:  20  10  20  30
+		 *     2:  30  20  10  20
+		 *     3:  40  30  20  10
+		 *
+		 *   0 --- 1 --- 2 --- 3
+		 *
+		 * NUMA-3       0-3             N/A             N/A             0-3
+		 *  groups:     {0-2},{1-3}                                     {1-3},{0-2}
+		 *
+		 * NUMA-2       0-2             0-3             0-3             1-3
+		 *  groups:     {0-1},{1-3}     {0-2},{2-3}     {1-3},{0-1}     {2-3},{0-2}
+		 *
+		 * NUMA-1       0-1             0-2             1-3             2-3
+		 *  groups:     {0},{1}         {1},{2},{0}     {2},{3},{1}     {3},{2}
+		 *
+		 * NUMA-0       0               1               2               3
+		 *
+		 * The NUMA-2 groups for nodes 0 and 3 are obviously buggered, as the
+		 * group span isn't a subset of the domain span.
+		 */
+		if (sibling->child &&
+		    !cpumask_subset(sched_domain_span(sibling->child), span))
+			sibling = find_descended_sibling(sd, sibling);
+
+		sg = build_group_from_child_sched_domain(sibling, cpu);
+		if (!sg)
+			goto fail;
+
+		sg_span = sched_group_span(sg);
+		cpumask_or(covered, covered, sg_span);
+
+		init_overlap_sched_group(sibling, sg);
+
+		if (!first)
+			first = sg;
+		if (last)
+			last->next = sg;
+		last = sg;
+		last->next = first;
+	}
+	sd->groups = first;
+
+	return 0;
+
+fail:
+	free_sched_groups(first, 0);
+
+	return -ENOMEM;
+}
+
+
+/*
+ * Package topology (also see the load-balance blurb in fair.c)
+ *
+ * The scheduler builds a tree structure to represent a number of important
+ * topology features. By default (default_topology[]) these include:
+ *
+ *  - Simultaneous multithreading (SMT)
+ *  - Multi-Core Cache (MC)
+ *  - Package (DIE)
+ *
+ * Where the last one more or less denotes everything up to a NUMA node.
+ *
+ * The tree consists of 3 primary data structures:
+ *
+ *	sched_domain -> sched_group -> sched_group_capacity
+ *	    ^ ^             ^ ^
+ *          `-'             `-'
+ *
+ * The sched_domains are per-CPU and have a two way link (parent & child) and
+ * denote the ever growing mask of CPUs belonging to that level of topology.
+ *
+ * Each sched_domain has a circular (double) linked list of sched_group's, each
+ * denoting the domains of the level below (or individual CPUs in case of the
+ * first domain level). The sched_group linked by a sched_domain includes the
+ * CPU of that sched_domain [*].
+ *
+ * Take for instance a 2 threaded, 2 core, 2 cache cluster part:
+ *
+ * CPU   0   1   2   3   4   5   6   7
+ *
+ * DIE  [                             ]
+ * MC   [             ] [             ]
+ * SMT  [     ] [     ] [     ] [     ]
+ *
+ *  - or -
+ *
+ * DIE  0-7 0-7 0-7 0-7 0-7 0-7 0-7 0-7
+ * MC	0-3 0-3 0-3 0-3 4-7 4-7 4-7 4-7
+ * SMT  0-1 0-1 2-3 2-3 4-5 4-5 6-7 6-7
+ *
+ * CPU   0   1   2   3   4   5   6   7
+ *
+ * One way to think about it is: sched_domain moves you up and down among these
+ * topology levels, while sched_group moves you sideways through it, at child
+ * domain granularity.
+ *
+ * sched_group_capacity ensures each unique sched_group has shared storage.
+ *
+ * There are two related construction problems, both require a CPU that
+ * uniquely identify each group (for a given domain):
+ *
+ *  - The first is the balance_cpu (see should_we_balance() and the
+ *    load-balance blub in fair.c); for each group we only want 1 CPU to
+ *    continue balancing at a higher domain.
+ *
+ *  - The second is the sched_group_capacity; we want all identical groups
+ *    to share a single sched_group_capacity.
+ *
+ * Since these topologies are exclusive by construction. That is, its
+ * impossible for an SMT thread to belong to multiple cores, and cores to
+ * be part of multiple caches. There is a very clear and unique location
+ * for each CPU in the hierarchy.
+ *
+ * Therefore computing a unique CPU for each group is trivial (the iteration
+ * mask is redundant and set all 1s; all CPUs in a group will end up at _that_
+ * group), we can simply pick the first CPU in each group.
+ *
+ *
+ * [*] in other words, the first group of each domain is its child domain.
+ */
+
+static struct sched_group *get_group(int cpu, struct sd_data *sdd)
+{
+	struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu);
+	struct sched_domain *child = sd->child;
+	struct sched_group *sg;
+	bool already_visited;
+
+	if (child)
+		cpu = cpumask_first(sched_domain_span(child));
+
+	sg = *per_cpu_ptr(sdd->sg, cpu);
+	sg->sgc = *per_cpu_ptr(sdd->sgc, cpu);
+
+	/* Increase refcounts for claim_allocations: */
+	already_visited = atomic_inc_return(&sg->ref) > 1;
+	/* sgc visits should follow a similar trend as sg */
+	WARN_ON(already_visited != (atomic_inc_return(&sg->sgc->ref) > 1));
+
+	/* If we have already visited that group, it's already initialized. */
+	if (already_visited)
+		return sg;
+
+	if (child) {
+		cpumask_copy(sched_group_span(sg), sched_domain_span(child));
+		cpumask_copy(group_balance_mask(sg), sched_group_span(sg));
+		sg->flags = child->flags;
+	} else {
+		cpumask_set_cpu(cpu, sched_group_span(sg));
+		cpumask_set_cpu(cpu, group_balance_mask(sg));
+	}
+
+	sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sched_group_span(sg));
+	sg->sgc->min_capacity = SCHED_CAPACITY_SCALE;
+	sg->sgc->max_capacity = SCHED_CAPACITY_SCALE;
+
+	return sg;
+}
+
+/*
+ * build_sched_groups will build a circular linked list of the groups
+ * covered by the given span, will set each group's ->cpumask correctly,
+ * and will initialize their ->sgc.
+ *
+ * Assumes the sched_domain tree is fully constructed
+ */
+static int
+build_sched_groups(struct sched_domain *sd, int cpu)
+{
+	struct sched_group *first = NULL, *last = NULL;
+	struct sd_data *sdd = sd->private;
+	const struct cpumask *span = sched_domain_span(sd);
+	struct cpumask *covered;
+	int i;
+
+	lockdep_assert_held(&sched_domains_mutex);
+	covered = sched_domains_tmpmask;
+
+	cpumask_clear(covered);
+
+	for_each_cpu_wrap(i, span, cpu) {
+		struct sched_group *sg;
+
+		if (cpumask_test_cpu(i, covered))
+			continue;
+
+		sg = get_group(i, sdd);
+
+		cpumask_or(covered, covered, sched_group_span(sg));
+
+		if (!first)
+			first = sg;
+		if (last)
+			last->next = sg;
+		last = sg;
+	}
+	last->next = first;
+	sd->groups = first;
+
+	return 0;
+}
+
+/*
+ * Initialize sched groups cpu_capacity.
+ *
+ * cpu_capacity indicates the capacity of sched group, which is used while
+ * distributing the load between different sched groups in a sched domain.
+ * Typically cpu_capacity for all the groups in a sched domain will be same
+ * unless there are asymmetries in the topology. If there are asymmetries,
+ * group having more cpu_capacity will pickup more load compared to the
+ * group having less cpu_capacity.
+ */
+static void init_sched_groups_capacity(int cpu, struct sched_domain *sd)
+{
+	struct sched_group *sg = sd->groups;
+	struct cpumask *mask = sched_domains_tmpmask2;
+
+	WARN_ON(!sg);
+
+	do {
+		int cpu, cores = 0, max_cpu = -1;
+
+		sg->group_weight = cpumask_weight(sched_group_span(sg));
+
+		cpumask_copy(mask, sched_group_span(sg));
+		for_each_cpu(cpu, mask) {
+			cores++;
+#ifdef CONFIG_SCHED_SMT
+			cpumask_andnot(mask, mask, cpu_smt_mask(cpu));
+#endif
+		}
+		sg->cores = cores;
+
+		if (!(sd->flags & SD_ASYM_PACKING))
+			goto next;
+
+		for_each_cpu(cpu, sched_group_span(sg)) {
+			if (max_cpu < 0)
+				max_cpu = cpu;
+			else if (sched_asym_prefer(cpu, max_cpu))
+				max_cpu = cpu;
+		}
+		sg->asym_prefer_cpu = max_cpu;
+
+next:
+		sg = sg->next;
+	} while (sg != sd->groups);
+
+	if (cpu != group_balance_cpu(sg))
+		return;
+
+	update_group_capacity(sd, cpu);
+}
+
+/*
+ * Asymmetric CPU capacity bits
+ */
+struct asym_cap_data {
+	struct list_head link;
+	unsigned long capacity;
+	unsigned long cpus[];
+};
+
+/*
+ * Set of available CPUs grouped by their corresponding capacities
+ * Each list entry contains a CPU mask reflecting CPUs that share the same
+ * capacity.
+ * The lifespan of data is unlimited.
+ */
+static LIST_HEAD(asym_cap_list);
+
+#define cpu_capacity_span(asym_data) to_cpumask((asym_data)->cpus)
+
+/*
+ * Verify whether there is any CPU capacity asymmetry in a given sched domain.
+ * Provides sd_flags reflecting the asymmetry scope.
+ */
+static inline int
+asym_cpu_capacity_classify(const struct cpumask *sd_span,
+			   const struct cpumask *cpu_map)
+{
+	struct asym_cap_data *entry;
+	int count = 0, miss = 0;
+
+	/*
+	 * Count how many unique CPU capacities this domain spans across
+	 * (compare sched_domain CPUs mask with ones representing  available
+	 * CPUs capacities). Take into account CPUs that might be offline:
+	 * skip those.
+	 */
+	list_for_each_entry(entry, &asym_cap_list, link) {
+		if (cpumask_intersects(sd_span, cpu_capacity_span(entry)))
+			++count;
+		else if (cpumask_intersects(cpu_map, cpu_capacity_span(entry)))
+			++miss;
+	}
+
+	WARN_ON_ONCE(!count && !list_empty(&asym_cap_list));
+
+	/* No asymmetry detected */
+	if (count < 2)
+		return 0;
+	/* Some of the available CPU capacity values have not been detected */
+	if (miss)
+		return SD_ASYM_CPUCAPACITY;
+
+	/* Full asymmetry */
+	return SD_ASYM_CPUCAPACITY | SD_ASYM_CPUCAPACITY_FULL;
+
+}
+
+static inline void asym_cpu_capacity_update_data(int cpu)
+{
+	unsigned long capacity = arch_scale_cpu_capacity(cpu);
+	struct asym_cap_data *entry = NULL;
+
+	list_for_each_entry(entry, &asym_cap_list, link) {
+		if (capacity == entry->capacity)
+			goto done;
+	}
+
+	entry = kzalloc(sizeof(*entry) + cpumask_size(), GFP_KERNEL);
+	if (WARN_ONCE(!entry, "Failed to allocate memory for asymmetry data\n"))
+		return;
+	entry->capacity = capacity;
+	list_add(&entry->link, &asym_cap_list);
+done:
+	__cpumask_set_cpu(cpu, cpu_capacity_span(entry));
+}
+
+/*
+ * Build-up/update list of CPUs grouped by their capacities
+ * An update requires explicit request to rebuild sched domains
+ * with state indicating CPU topology changes.
+ */
+static void asym_cpu_capacity_scan(void)
+{
+	struct asym_cap_data *entry, *next;
+	int cpu;
+
+	list_for_each_entry(entry, &asym_cap_list, link)
+		cpumask_clear(cpu_capacity_span(entry));
+
+	for_each_cpu_and(cpu, cpu_possible_mask, housekeeping_cpumask(HK_TYPE_DOMAIN))
+		asym_cpu_capacity_update_data(cpu);
+
+	list_for_each_entry_safe(entry, next, &asym_cap_list, link) {
+		if (cpumask_empty(cpu_capacity_span(entry))) {
+			list_del(&entry->link);
+			kfree(entry);
+		}
+	}
+
+	/*
+	 * Only one capacity value has been detected i.e. this system is symmetric.
+	 * No need to keep this data around.
+	 */
+	if (list_is_singular(&asym_cap_list)) {
+		entry = list_first_entry(&asym_cap_list, typeof(*entry), link);
+		list_del(&entry->link);
+		kfree(entry);
+	}
+}
+
+/*
+ * Initializers for schedule domains
+ * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
+ */
+
+static int default_relax_domain_level = -1;
+int sched_domain_level_max;
+
+static int __init setup_relax_domain_level(char *str)
+{
+	if (kstrtoint(str, 0, &default_relax_domain_level))
+		pr_warn("Unable to set relax_domain_level\n");
+
+	return 1;
+}
+__setup("relax_domain_level=", setup_relax_domain_level);
+
+static void set_domain_attribute(struct sched_domain *sd,
+				 struct sched_domain_attr *attr)
+{
+	int request;
+
+	if (!attr || attr->relax_domain_level < 0) {
+		if (default_relax_domain_level < 0)
+			return;
+		request = default_relax_domain_level;
+	} else
+		request = attr->relax_domain_level;
+
+	if (sd->level > request) {
+		/* Turn off idle balance on this domain: */
+		sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
+	}
+}
+
+static void __sdt_free(const struct cpumask *cpu_map);
+static int __sdt_alloc(const struct cpumask *cpu_map);
+
+static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
+				 const struct cpumask *cpu_map)
+{
+	switch (what) {
+	case sa_rootdomain:
+		if (!atomic_read(&d->rd->refcount))
+			free_rootdomain(&d->rd->rcu);
+		fallthrough;
+	case sa_sd:
+		free_percpu(d->sd);
+		fallthrough;
+	case sa_sd_storage:
+		__sdt_free(cpu_map);
+		fallthrough;
+	case sa_none:
+		break;
+	}
+}
+
+static enum s_alloc
+__visit_domain_allocation_hell(struct s_data *d, const struct cpumask *cpu_map)
+{
+	memset(d, 0, sizeof(*d));
+
+	if (__sdt_alloc(cpu_map))
+		return sa_sd_storage;
+	d->sd = alloc_percpu(struct sched_domain *);
+	if (!d->sd)
+		return sa_sd_storage;
+	d->rd = alloc_rootdomain();
+	if (!d->rd)
+		return sa_sd;
+
+	return sa_rootdomain;
+}
+
+/*
+ * NULL the sd_data elements we've used to build the sched_domain and
+ * sched_group structure so that the subsequent __free_domain_allocs()
+ * will not free the data we're using.
+ */
+static void claim_allocations(int cpu, struct sched_domain *sd)
+{
+	struct sd_data *sdd = sd->private;
+
+	WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd);
+	*per_cpu_ptr(sdd->sd, cpu) = NULL;
+
+	if (atomic_read(&(*per_cpu_ptr(sdd->sds, cpu))->ref))
+		*per_cpu_ptr(sdd->sds, cpu) = NULL;
+
+	if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref))
+		*per_cpu_ptr(sdd->sg, cpu) = NULL;
+
+	if (atomic_read(&(*per_cpu_ptr(sdd->sgc, cpu))->ref))
+		*per_cpu_ptr(sdd->sgc, cpu) = NULL;
+}
+
+#ifdef CONFIG_NUMA
+enum numa_topology_type sched_numa_topology_type;
+
+static int			sched_domains_numa_levels;
+static int			sched_domains_curr_level;
+
+int				sched_max_numa_distance;
+static int			*sched_domains_numa_distance;
+static struct cpumask		***sched_domains_numa_masks;
+#endif
+
+/*
+ * SD_flags allowed in topology descriptions.
+ *
+ * These flags are purely descriptive of the topology and do not prescribe
+ * behaviour. Behaviour is artificial and mapped in the below sd_init()
+ * function:
+ *
+ *   SD_SHARE_CPUCAPACITY   - describes SMT topologies
+ *   SD_SHARE_PKG_RESOURCES - describes shared caches
+ *   SD_NUMA                - describes NUMA topologies
+ *
+ * Odd one out, which beside describing the topology has a quirk also
+ * prescribes the desired behaviour that goes along with it:
+ *
+ *   SD_ASYM_PACKING        - describes SMT quirks
+ */
+#define TOPOLOGY_SD_FLAGS		\
+	(SD_SHARE_CPUCAPACITY	|	\
+	 SD_SHARE_PKG_RESOURCES |	\
+	 SD_NUMA		|	\
+	 SD_ASYM_PACKING)
+
+static struct sched_domain *
+sd_init(struct sched_domain_topology_level *tl,
+	const struct cpumask *cpu_map,
+	struct sched_domain *child, int cpu)
+{
+	struct sd_data *sdd = &tl->data;
+	struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu);
+	int sd_id, sd_weight, sd_flags = 0;
+	struct cpumask *sd_span;
+
+#ifdef CONFIG_NUMA
+	/*
+	 * Ugly hack to pass state to sd_numa_mask()...
+	 */
+	sched_domains_curr_level = tl->numa_level;
+#endif
+
+	sd_weight = cpumask_weight(tl->mask(cpu));
+
+	if (tl->sd_flags)
+		sd_flags = (*tl->sd_flags)();
+	if (WARN_ONCE(sd_flags & ~TOPOLOGY_SD_FLAGS,
+			"wrong sd_flags in topology description\n"))
+		sd_flags &= TOPOLOGY_SD_FLAGS;
+
+	*sd = (struct sched_domain){
+		.min_interval		= sd_weight,
+		.max_interval		= 2*sd_weight,
+		.busy_factor		= 16,
+		.imbalance_pct		= 117,
+
+		.cache_nice_tries	= 0,
+
+		.flags			= 1*SD_BALANCE_NEWIDLE
+					| 1*SD_BALANCE_EXEC
+					| 1*SD_BALANCE_FORK
+					| 0*SD_BALANCE_WAKE
+					| 1*SD_WAKE_AFFINE
+					| 0*SD_SHARE_CPUCAPACITY
+					| 0*SD_SHARE_PKG_RESOURCES
+					| 0*SD_SERIALIZE
+					| 1*SD_PREFER_SIBLING
+					| 0*SD_NUMA
+					| sd_flags
+					,
+
+		.last_balance		= jiffies,
+		.balance_interval	= sd_weight,
+		.max_newidle_lb_cost	= 0,
+		.last_decay_max_lb_cost	= jiffies,
+		.child			= child,
+#ifdef CONFIG_SCHED_DEBUG
+		.name			= tl->name,
+#endif
+	};
+
+	sd_span = sched_domain_span(sd);
+	cpumask_and(sd_span, cpu_map, tl->mask(cpu));
+	sd_id = cpumask_first(sd_span);
+
+	sd->flags |= asym_cpu_capacity_classify(sd_span, cpu_map);
+
+	WARN_ONCE((sd->flags & (SD_SHARE_CPUCAPACITY | SD_ASYM_CPUCAPACITY)) ==
+		  (SD_SHARE_CPUCAPACITY | SD_ASYM_CPUCAPACITY),
+		  "CPU capacity asymmetry not supported on SMT\n");
+
+	/*
+	 * Convert topological properties into behaviour.
+	 */
+	/* Don't attempt to spread across CPUs of different capacities. */
+	if ((sd->flags & SD_ASYM_CPUCAPACITY) && sd->child)
+		sd->child->flags &= ~SD_PREFER_SIBLING;
+
+	if (sd->flags & SD_SHARE_CPUCAPACITY) {
+		sd->imbalance_pct = 110;
+
+	} else if (sd->flags & SD_SHARE_PKG_RESOURCES) {
+		sd->imbalance_pct = 117;
+		sd->cache_nice_tries = 1;
+
+#ifdef CONFIG_NUMA
+	} else if (sd->flags & SD_NUMA) {
+		sd->cache_nice_tries = 2;
+
+		sd->flags &= ~SD_PREFER_SIBLING;
+		sd->flags |= SD_SERIALIZE;
+		if (sched_domains_numa_distance[tl->numa_level] > node_reclaim_distance) {
+			sd->flags &= ~(SD_BALANCE_EXEC |
+				       SD_BALANCE_FORK |
+				       SD_WAKE_AFFINE);
+		}
+
+#endif
+	} else {
+		sd->cache_nice_tries = 1;
+	}
+
+	/*
+	 * For all levels sharing cache; connect a sched_domain_shared
+	 * instance.
+	 */
+	if (sd->flags & SD_SHARE_PKG_RESOURCES) {
+		sd->shared = *per_cpu_ptr(sdd->sds, sd_id);
+		atomic_inc(&sd->shared->ref);
+		atomic_set(&sd->shared->nr_busy_cpus, sd_weight);
+	}
+
+	sd->private = sdd;
+
+	return sd;
+}
+
+/*
+ * Topology list, bottom-up.
+ */
+static struct sched_domain_topology_level default_topology[] = {
+#ifdef CONFIG_SCHED_SMT
+	{ cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
+#endif
+
+#ifdef CONFIG_SCHED_CLUSTER
+	{ cpu_clustergroup_mask, cpu_cluster_flags, SD_INIT_NAME(CLS) },
+#endif
+
+#ifdef CONFIG_SCHED_MC
+	{ cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
+#endif
+	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
+	{ NULL, },
+};
+
+static struct sched_domain_topology_level *sched_domain_topology =
+	default_topology;
+static struct sched_domain_topology_level *sched_domain_topology_saved;
+
+#define for_each_sd_topology(tl)			\
+	for (tl = sched_domain_topology; tl->mask; tl++)
+
+void __init set_sched_topology(struct sched_domain_topology_level *tl)
+{
+	if (WARN_ON_ONCE(sched_smp_initialized))
+		return;
+
+	sched_domain_topology = tl;
+	sched_domain_topology_saved = NULL;
+}
+
+#ifdef CONFIG_NUMA
+
+static const struct cpumask *sd_numa_mask(int cpu)
+{
+	return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)];
+}
+
+static void sched_numa_warn(const char *str)
+{
+	static int done = false;
+	int i,j;
+
+	if (done)
+		return;
+
+	done = true;
+
+	printk(KERN_WARNING "ERROR: %s\n\n", str);
+
+	for (i = 0; i < nr_node_ids; i++) {
+		printk(KERN_WARNING "  ");
+		for (j = 0; j < nr_node_ids; j++) {
+			if (!node_state(i, N_CPU) || !node_state(j, N_CPU))
+				printk(KERN_CONT "(%02d) ", node_distance(i,j));
+			else
+				printk(KERN_CONT " %02d  ", node_distance(i,j));
+		}
+		printk(KERN_CONT "\n");
+	}
+	printk(KERN_WARNING "\n");
+}
+
+bool find_numa_distance(int distance)
+{
+	bool found = false;
+	int i, *distances;
+
+	if (distance == node_distance(0, 0))
+		return true;
+
+	rcu_read_lock();
+	distances = rcu_dereference(sched_domains_numa_distance);
+	if (!distances)
+		goto unlock;
+	for (i = 0; i < sched_domains_numa_levels; i++) {
+		if (distances[i] == distance) {
+			found = true;
+			break;
+		}
+	}
+unlock:
+	rcu_read_unlock();
+
+	return found;
+}
+
+#define for_each_cpu_node_but(n, nbut)		\
+	for_each_node_state(n, N_CPU)		\
+		if (n == nbut)			\
+			continue;		\
+		else
+
+/*
+ * A system can have three types of NUMA topology:
+ * NUMA_DIRECT: all nodes are directly connected, or not a NUMA system
+ * NUMA_GLUELESS_MESH: some nodes reachable through intermediary nodes
+ * NUMA_BACKPLANE: nodes can reach other nodes through a backplane
+ *
+ * The difference between a glueless mesh topology and a backplane
+ * topology lies in whether communication between not directly
+ * connected nodes goes through intermediary nodes (where programs
+ * could run), or through backplane controllers. This affects
+ * placement of programs.
+ *
+ * The type of topology can be discerned with the following tests:
+ * - If the maximum distance between any nodes is 1 hop, the system
+ *   is directly connected.
+ * - If for two nodes A and B, located N > 1 hops away from each other,
+ *   there is an intermediary node C, which is < N hops away from both
+ *   nodes A and B, the system is a glueless mesh.
+ */
+static void init_numa_topology_type(int offline_node)
+{
+	int a, b, c, n;
+
+	n = sched_max_numa_distance;
+
+	if (sched_domains_numa_levels <= 2) {
+		sched_numa_topology_type = NUMA_DIRECT;
+		return;
+	}
+
+	for_each_cpu_node_but(a, offline_node) {
+		for_each_cpu_node_but(b, offline_node) {
+			/* Find two nodes furthest removed from each other. */
+			if (node_distance(a, b) < n)
+				continue;
+
+			/* Is there an intermediary node between a and b? */
+			for_each_cpu_node_but(c, offline_node) {
+				if (node_distance(a, c) < n &&
+				    node_distance(b, c) < n) {
+					sched_numa_topology_type =
+							NUMA_GLUELESS_MESH;
+					return;
+				}
+			}
+
+			sched_numa_topology_type = NUMA_BACKPLANE;
+			return;
+		}
+	}
+
+	pr_err("Failed to find a NUMA topology type, defaulting to DIRECT\n");
+	sched_numa_topology_type = NUMA_DIRECT;
+}
+
+
+#define NR_DISTANCE_VALUES (1 << DISTANCE_BITS)
+
+void sched_init_numa(int offline_node)
+{
+	struct sched_domain_topology_level *tl;
+	unsigned long *distance_map;
+	int nr_levels = 0;
+	int i, j;
+	int *distances;
+	struct cpumask ***masks;
+
+	/*
+	 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
+	 * unique distances in the node_distance() table.
+	 */
+	distance_map = bitmap_alloc(NR_DISTANCE_VALUES, GFP_KERNEL);
+	if (!distance_map)
+		return;
+
+	bitmap_zero(distance_map, NR_DISTANCE_VALUES);
+	for_each_cpu_node_but(i, offline_node) {
+		for_each_cpu_node_but(j, offline_node) {
+			int distance = node_distance(i, j);
+
+			if (distance < LOCAL_DISTANCE || distance >= NR_DISTANCE_VALUES) {
+				sched_numa_warn("Invalid distance value range");
+				bitmap_free(distance_map);
+				return;
+			}
+
+			bitmap_set(distance_map, distance, 1);
+		}
+	}
+	/*
+	 * We can now figure out how many unique distance values there are and
+	 * allocate memory accordingly.
+	 */
+	nr_levels = bitmap_weight(distance_map, NR_DISTANCE_VALUES);
+
+	distances = kcalloc(nr_levels, sizeof(int), GFP_KERNEL);
+	if (!distances) {
+		bitmap_free(distance_map);
+		return;
+	}
+
+	for (i = 0, j = 0; i < nr_levels; i++, j++) {
+		j = find_next_bit(distance_map, NR_DISTANCE_VALUES, j);
+		distances[i] = j;
+	}
+	rcu_assign_pointer(sched_domains_numa_distance, distances);
+
+	bitmap_free(distance_map);
+
+	/*
+	 * 'nr_levels' contains the number of unique distances
+	 *
+	 * The sched_domains_numa_distance[] array includes the actual distance
+	 * numbers.
+	 */
+
+	/*
+	 * Here, we should temporarily reset sched_domains_numa_levels to 0.
+	 * If it fails to allocate memory for array sched_domains_numa_masks[][],
+	 * the array will contain less then 'nr_levels' members. This could be
+	 * dangerous when we use it to iterate array sched_domains_numa_masks[][]
+	 * in other functions.
+	 *
+	 * We reset it to 'nr_levels' at the end of this function.
+	 */
+	sched_domains_numa_levels = 0;
+
+	masks = kzalloc(sizeof(void *) * nr_levels, GFP_KERNEL);
+	if (!masks)
+		return;
+
+	/*
+	 * Now for each level, construct a mask per node which contains all
+	 * CPUs of nodes that are that many hops away from us.
+	 */
+	for (i = 0; i < nr_levels; i++) {
+		masks[i] = kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL);
+		if (!masks[i])
+			return;
+
+		for_each_cpu_node_but(j, offline_node) {
+			struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL);
+			int k;
+
+			if (!mask)
+				return;
+
+			masks[i][j] = mask;
+
+			for_each_cpu_node_but(k, offline_node) {
+				if (sched_debug() && (node_distance(j, k) != node_distance(k, j)))
+					sched_numa_warn("Node-distance not symmetric");
+
+				if (node_distance(j, k) > sched_domains_numa_distance[i])
+					continue;
+
+				cpumask_or(mask, mask, cpumask_of_node(k));
+			}
+		}
+	}
+	rcu_assign_pointer(sched_domains_numa_masks, masks);
+
+	/* Compute default topology size */
+	for (i = 0; sched_domain_topology[i].mask; i++);
+
+	tl = kzalloc((i + nr_levels + 1) *
+			sizeof(struct sched_domain_topology_level), GFP_KERNEL);
+	if (!tl)
+		return;
+
+	/*
+	 * Copy the default topology bits..
+	 */
+	for (i = 0; sched_domain_topology[i].mask; i++)
+		tl[i] = sched_domain_topology[i];
+
+	/*
+	 * Add the NUMA identity distance, aka single NODE.
+	 */
+	tl[i++] = (struct sched_domain_topology_level){
+		.mask = sd_numa_mask,
+		.numa_level = 0,
+		SD_INIT_NAME(NODE)
+	};
+
+	/*
+	 * .. and append 'j' levels of NUMA goodness.
+	 */
+	for (j = 1; j < nr_levels; i++, j++) {
+		tl[i] = (struct sched_domain_topology_level){
+			.mask = sd_numa_mask,
+			.sd_flags = cpu_numa_flags,
+			.flags = SDTL_OVERLAP,
+			.numa_level = j,
+			SD_INIT_NAME(NUMA)
+		};
+	}
+
+	sched_domain_topology_saved = sched_domain_topology;
+	sched_domain_topology = tl;
+
+	sched_domains_numa_levels = nr_levels;
+	WRITE_ONCE(sched_max_numa_distance, sched_domains_numa_distance[nr_levels - 1]);
+
+	init_numa_topology_type(offline_node);
+}
+
+
+static void sched_reset_numa(void)
+{
+	int nr_levels, *distances;
+	struct cpumask ***masks;
+
+	nr_levels = sched_domains_numa_levels;
+	sched_domains_numa_levels = 0;
+	sched_max_numa_distance = 0;
+	sched_numa_topology_type = NUMA_DIRECT;
+	distances = sched_domains_numa_distance;
+	rcu_assign_pointer(sched_domains_numa_distance, NULL);
+	masks = sched_domains_numa_masks;
+	rcu_assign_pointer(sched_domains_numa_masks, NULL);
+	if (distances || masks) {
+		int i, j;
+
+		synchronize_rcu();
+		kfree(distances);
+		for (i = 0; i < nr_levels && masks; i++) {
+			if (!masks[i])
+				continue;
+			for_each_node(j)
+				kfree(masks[i][j]);
+			kfree(masks[i]);
+		}
+		kfree(masks);
+	}
+	if (sched_domain_topology_saved) {
+		kfree(sched_domain_topology);
+		sched_domain_topology = sched_domain_topology_saved;
+		sched_domain_topology_saved = NULL;
+	}
+}
+
+/*
+ * Call with hotplug lock held
+ */
+void sched_update_numa(int cpu, bool online)
+{
+	int node;
+
+	node = cpu_to_node(cpu);
+	/*
+	 * Scheduler NUMA topology is updated when the first CPU of a
+	 * node is onlined or the last CPU of a node is offlined.
+	 */
+	if (cpumask_weight(cpumask_of_node(node)) != 1)
+		return;
+
+	sched_reset_numa();
+	sched_init_numa(online ? NUMA_NO_NODE : node);
+}
+
+void sched_domains_numa_masks_set(unsigned int cpu)
+{
+	int node = cpu_to_node(cpu);
+	int i, j;
+
+	for (i = 0; i < sched_domains_numa_levels; i++) {
+		for (j = 0; j < nr_node_ids; j++) {
+			if (!node_state(j, N_CPU))
+				continue;
+
+			/* Set ourselves in the remote node's masks */
+			if (node_distance(j, node) <= sched_domains_numa_distance[i])
+				cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]);
+		}
+	}
+}
+
+void sched_domains_numa_masks_clear(unsigned int cpu)
+{
+	int i, j;
+
+	for (i = 0; i < sched_domains_numa_levels; i++) {
+		for (j = 0; j < nr_node_ids; j++) {
+			if (sched_domains_numa_masks[i][j])
+				cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]);
+		}
+	}
+}
+
+/*
+ * sched_numa_find_closest() - given the NUMA topology, find the cpu
+ *                             closest to @cpu from @cpumask.
+ * cpumask: cpumask to find a cpu from
+ * cpu: cpu to be close to
+ *
+ * returns: cpu, or nr_cpu_ids when nothing found.
+ */
+int sched_numa_find_closest(const struct cpumask *cpus, int cpu)
+{
+	int i, j = cpu_to_node(cpu), found = nr_cpu_ids;
+	struct cpumask ***masks;
+
+	rcu_read_lock();
+	masks = rcu_dereference(sched_domains_numa_masks);
+	if (!masks)
+		goto unlock;
+	for (i = 0; i < sched_domains_numa_levels; i++) {
+		if (!masks[i][j])
+			break;
+		cpu = cpumask_any_and(cpus, masks[i][j]);
+		if (cpu < nr_cpu_ids) {
+			found = cpu;
+			break;
+		}
+	}
+unlock:
+	rcu_read_unlock();
+
+	return found;
+}
+
+struct __cmp_key {
+	const struct cpumask *cpus;
+	struct cpumask ***masks;
+	int node;
+	int cpu;
+	int w;
+};
+
+static int hop_cmp(const void *a, const void *b)
+{
+	struct cpumask **prev_hop, **cur_hop = *(struct cpumask ***)b;
+	struct __cmp_key *k = (struct __cmp_key *)a;
+
+	if (cpumask_weight_and(k->cpus, cur_hop[k->node]) <= k->cpu)
+		return 1;
+
+	if (b == k->masks) {
+		k->w = 0;
+		return 0;
+	}
+
+	prev_hop = *((struct cpumask ***)b - 1);
+	k->w = cpumask_weight_and(k->cpus, prev_hop[k->node]);
+	if (k->w <= k->cpu)
+		return 0;
+
+	return -1;
+}
+
+/*
+ * sched_numa_find_nth_cpu() - given the NUMA topology, find the Nth next cpu
+ *                             closest to @cpu from @cpumask.
+ * cpumask: cpumask to find a cpu from
+ * cpu: Nth cpu to find
+ *
+ * returns: cpu, or nr_cpu_ids when nothing found.
+ */
+int sched_numa_find_nth_cpu(const struct cpumask *cpus, int cpu, int node)
+{
+	struct __cmp_key k = { .cpus = cpus, .cpu = cpu };
+	struct cpumask ***hop_masks;
+	int hop, ret = nr_cpu_ids;
+
+	rcu_read_lock();
+
+	/* CPU-less node entries are uninitialized in sched_domains_numa_masks */
+	node = numa_nearest_node(node, N_CPU);
+	k.node = node;
+
+	k.masks = rcu_dereference(sched_domains_numa_masks);
+	if (!k.masks)
+		goto unlock;
+
+	hop_masks = bsearch(&k, k.masks, sched_domains_numa_levels, sizeof(k.masks[0]), hop_cmp);
+	hop = hop_masks	- k.masks;
+
+	ret = hop ?
+		cpumask_nth_and_andnot(cpu - k.w, cpus, k.masks[hop][node], k.masks[hop-1][node]) :
+		cpumask_nth_and(cpu, cpus, k.masks[0][node]);
+unlock:
+	rcu_read_unlock();
+	return ret;
+}
+EXPORT_SYMBOL_GPL(sched_numa_find_nth_cpu);
+
+/**
+ * sched_numa_hop_mask() - Get the cpumask of CPUs at most @hops hops away from
+ *                         @node
+ * @node: The node to count hops from.
+ * @hops: Include CPUs up to that many hops away. 0 means local node.
+ *
+ * Return: On success, a pointer to a cpumask of CPUs at most @hops away from
+ * @node, an error value otherwise.
+ *
+ * Requires rcu_lock to be held. Returned cpumask is only valid within that
+ * read-side section, copy it if required beyond that.
+ *
+ * Note that not all hops are equal in distance; see sched_init_numa() for how
+ * distances and masks are handled.
+ * Also note that this is a reflection of sched_domains_numa_masks, which may change
+ * during the lifetime of the system (offline nodes are taken out of the masks).
+ */
+const struct cpumask *sched_numa_hop_mask(unsigned int node, unsigned int hops)
+{
+	struct cpumask ***masks;
+
+	if (node >= nr_node_ids || hops >= sched_domains_numa_levels)
+		return ERR_PTR(-EINVAL);
+
+	masks = rcu_dereference(sched_domains_numa_masks);
+	if (!masks)
+		return ERR_PTR(-EBUSY);
+
+	return masks[hops][node];
+}
+EXPORT_SYMBOL_GPL(sched_numa_hop_mask);
+
+#endif /* CONFIG_NUMA */
+
+static int __sdt_alloc(const struct cpumask *cpu_map)
+{
+	struct sched_domain_topology_level *tl;
+	int j;
+
+	for_each_sd_topology(tl) {
+		struct sd_data *sdd = &tl->data;
+
+		sdd->sd = alloc_percpu(struct sched_domain *);
+		if (!sdd->sd)
+			return -ENOMEM;
+
+		sdd->sds = alloc_percpu(struct sched_domain_shared *);
+		if (!sdd->sds)
+			return -ENOMEM;
+
+		sdd->sg = alloc_percpu(struct sched_group *);
+		if (!sdd->sg)
+			return -ENOMEM;
+
+		sdd->sgc = alloc_percpu(struct sched_group_capacity *);
+		if (!sdd->sgc)
+			return -ENOMEM;
+
+		for_each_cpu(j, cpu_map) {
+			struct sched_domain *sd;
+			struct sched_domain_shared *sds;
+			struct sched_group *sg;
+			struct sched_group_capacity *sgc;
+
+			sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(),
+					GFP_KERNEL, cpu_to_node(j));
+			if (!sd)
+				return -ENOMEM;
+
+			*per_cpu_ptr(sdd->sd, j) = sd;
+
+			sds = kzalloc_node(sizeof(struct sched_domain_shared),
+					GFP_KERNEL, cpu_to_node(j));
+			if (!sds)
+				return -ENOMEM;
+
+			*per_cpu_ptr(sdd->sds, j) = sds;
+
+			sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
+					GFP_KERNEL, cpu_to_node(j));
+			if (!sg)
+				return -ENOMEM;
+
+			sg->next = sg;
+
+			*per_cpu_ptr(sdd->sg, j) = sg;
+
+			sgc = kzalloc_node(sizeof(struct sched_group_capacity) + cpumask_size(),
+					GFP_KERNEL, cpu_to_node(j));
+			if (!sgc)
+				return -ENOMEM;
+
+#ifdef CONFIG_SCHED_DEBUG
+			sgc->id = j;
+#endif
+
+			*per_cpu_ptr(sdd->sgc, j) = sgc;
+		}
+	}
+
+	return 0;
+}
+
+static void __sdt_free(const struct cpumask *cpu_map)
+{
+	struct sched_domain_topology_level *tl;
+	int j;
+
+	for_each_sd_topology(tl) {
+		struct sd_data *sdd = &tl->data;
+
+		for_each_cpu(j, cpu_map) {
+			struct sched_domain *sd;
+
+			if (sdd->sd) {
+				sd = *per_cpu_ptr(sdd->sd, j);
+				if (sd && (sd->flags & SD_OVERLAP))
+					free_sched_groups(sd->groups, 0);
+				kfree(*per_cpu_ptr(sdd->sd, j));
+			}
+
+			if (sdd->sds)
+				kfree(*per_cpu_ptr(sdd->sds, j));
+			if (sdd->sg)
+				kfree(*per_cpu_ptr(sdd->sg, j));
+			if (sdd->sgc)
+				kfree(*per_cpu_ptr(sdd->sgc, j));
+		}
+		free_percpu(sdd->sd);
+		sdd->sd = NULL;
+		free_percpu(sdd->sds);
+		sdd->sds = NULL;
+		free_percpu(sdd->sg);
+		sdd->sg = NULL;
+		free_percpu(sdd->sgc);
+		sdd->sgc = NULL;
+	}
+}
+
+static struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,
+		const struct cpumask *cpu_map, struct sched_domain_attr *attr,
+		struct sched_domain *child, int cpu)
+{
+	struct sched_domain *sd = sd_init(tl, cpu_map, child, cpu);
+
+	if (child) {
+		sd->level = child->level + 1;
+		sched_domain_level_max = max(sched_domain_level_max, sd->level);
+		child->parent = sd;
+
+		if (!cpumask_subset(sched_domain_span(child),
+				    sched_domain_span(sd))) {
+			pr_err("BUG: arch topology borken\n");
+#ifdef CONFIG_SCHED_DEBUG
+			pr_err("     the %s domain not a subset of the %s domain\n",
+					child->name, sd->name);
+#endif
+			/* Fixup, ensure @sd has at least @child CPUs. */
+			cpumask_or(sched_domain_span(sd),
+				   sched_domain_span(sd),
+				   sched_domain_span(child));
+		}
+
+	}
+	set_domain_attribute(sd, attr);
+
+	return sd;
+}
+
+/*
+ * Ensure topology masks are sane, i.e. there are no conflicts (overlaps) for
+ * any two given CPUs at this (non-NUMA) topology level.
+ */
+static bool topology_span_sane(struct sched_domain_topology_level *tl,
+			      const struct cpumask *cpu_map, int cpu)
+{
+	int i;
+
+	/* NUMA levels are allowed to overlap */
+	if (tl->flags & SDTL_OVERLAP)
+		return true;
+
+	/*
+	 * Non-NUMA levels cannot partially overlap - they must be either
+	 * completely equal or completely disjoint. Otherwise we can end up
+	 * breaking the sched_group lists - i.e. a later get_group() pass
+	 * breaks the linking done for an earlier span.
+	 */
+	for_each_cpu(i, cpu_map) {
+		if (i == cpu)
+			continue;
+		/*
+		 * We should 'and' all those masks with 'cpu_map' to exactly
+		 * match the topology we're about to build, but that can only
+		 * remove CPUs, which only lessens our ability to detect
+		 * overlaps
+		 */
+		if (!cpumask_equal(tl->mask(cpu), tl->mask(i)) &&
+		    cpumask_intersects(tl->mask(cpu), tl->mask(i)))
+			return false;
+	}
+
+	return true;
+}
+
+/*
+ * Build sched domains for a given set of CPUs and attach the sched domains
+ * to the individual CPUs
+ */
+static int
+build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *attr)
+{
+	enum s_alloc alloc_state = sa_none;
+	struct sched_domain *sd;
+	struct s_data d;
+	struct rq *rq = NULL;
+	int i, ret = -ENOMEM;
+	bool has_asym = false;
+
+	if (WARN_ON(cpumask_empty(cpu_map)))
+		goto error;
+
+	alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
+	if (alloc_state != sa_rootdomain)
+		goto error;
+
+	/* Set up domains for CPUs specified by the cpu_map: */
+	for_each_cpu(i, cpu_map) {
+		struct sched_domain_topology_level *tl;
+
+		sd = NULL;
+		for_each_sd_topology(tl) {
+
+			if (WARN_ON(!topology_span_sane(tl, cpu_map, i)))
+				goto error;
+
+			sd = build_sched_domain(tl, cpu_map, attr, sd, i);
+
+			has_asym |= sd->flags & SD_ASYM_CPUCAPACITY;
+
+			if (tl == sched_domain_topology)
+				*per_cpu_ptr(d.sd, i) = sd;
+			if (tl->flags & SDTL_OVERLAP)
+				sd->flags |= SD_OVERLAP;
+			if (cpumask_equal(cpu_map, sched_domain_span(sd)))
+				break;
+		}
+	}
+
+	/* Build the groups for the domains */
+	for_each_cpu(i, cpu_map) {
+		for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
+			sd->span_weight = cpumask_weight(sched_domain_span(sd));
+			if (sd->flags & SD_OVERLAP) {
+				if (build_overlap_sched_groups(sd, i))
+					goto error;
+			} else {
+				if (build_sched_groups(sd, i))
+					goto error;
+			}
+		}
+	}
+
+	/*
+	 * Calculate an allowed NUMA imbalance such that LLCs do not get
+	 * imbalanced.
+	 */
+	for_each_cpu(i, cpu_map) {
+		unsigned int imb = 0;
+		unsigned int imb_span = 1;
+
+		for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
+			struct sched_domain *child = sd->child;
+
+			if (!(sd->flags & SD_SHARE_PKG_RESOURCES) && child &&
+			    (child->flags & SD_SHARE_PKG_RESOURCES)) {
+				struct sched_domain __rcu *top_p;
+				unsigned int nr_llcs;
+
+				/*
+				 * For a single LLC per node, allow an
+				 * imbalance up to 12.5% of the node. This is
+				 * arbitrary cutoff based two factors -- SMT and
+				 * memory channels. For SMT-2, the intent is to
+				 * avoid premature sharing of HT resources but
+				 * SMT-4 or SMT-8 *may* benefit from a different
+				 * cutoff. For memory channels, this is a very
+				 * rough estimate of how many channels may be
+				 * active and is based on recent CPUs with
+				 * many cores.
+				 *
+				 * For multiple LLCs, allow an imbalance
+				 * until multiple tasks would share an LLC
+				 * on one node while LLCs on another node
+				 * remain idle. This assumes that there are
+				 * enough logical CPUs per LLC to avoid SMT
+				 * factors and that there is a correlation
+				 * between LLCs and memory channels.
+				 */
+				nr_llcs = sd->span_weight / child->span_weight;
+				if (nr_llcs == 1)
+					imb = sd->span_weight >> 3;
+				else
+					imb = nr_llcs;
+				imb = max(1U, imb);
+				sd->imb_numa_nr = imb;
+
+				/* Set span based on the first NUMA domain. */
+				top_p = sd->parent;
+				while (top_p && !(top_p->flags & SD_NUMA)) {
+					top_p = top_p->parent;
+				}
+				imb_span = top_p ? top_p->span_weight : sd->span_weight;
+			} else {
+				int factor = max(1U, (sd->span_weight / imb_span));
+
+				sd->imb_numa_nr = imb * factor;
+			}
+		}
+	}
+
+	/* Calculate CPU capacity for physical packages and nodes */
+	for (i = nr_cpumask_bits-1; i >= 0; i--) {
+		if (!cpumask_test_cpu(i, cpu_map))
+			continue;
+
+		for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
+			claim_allocations(i, sd);
+			init_sched_groups_capacity(i, sd);
+		}
+	}
+
+	/* Attach the domains */
+	rcu_read_lock();
+	for_each_cpu(i, cpu_map) {
+		rq = cpu_rq(i);
+		sd = *per_cpu_ptr(d.sd, i);
+
+		/* Use READ_ONCE()/WRITE_ONCE() to avoid load/store tearing: */
+		if (rq->cpu_capacity_orig > READ_ONCE(d.rd->max_cpu_capacity))
+			WRITE_ONCE(d.rd->max_cpu_capacity, rq->cpu_capacity_orig);
+
+		cpu_attach_domain(sd, d.rd, i);
+	}
+	rcu_read_unlock();
+
+	if (has_asym)
+		static_branch_inc_cpuslocked(&sched_asym_cpucapacity);
+
+	if (rq && sched_debug_verbose) {
+		pr_info("root domain span: %*pbl (max cpu_capacity = %lu)\n",
+			cpumask_pr_args(cpu_map), rq->rd->max_cpu_capacity);
+	}
+
+	ret = 0;
+error:
+	__free_domain_allocs(&d, alloc_state, cpu_map);
+
+	return ret;
+}
+
+/* Current sched domains: */
+static cpumask_var_t			*doms_cur;
+
+/* Number of sched domains in 'doms_cur': */
+static int				ndoms_cur;
+
+/* Attributes of custom domains in 'doms_cur' */
+static struct sched_domain_attr		*dattr_cur;
+
+/*
+ * Special case: If a kmalloc() of a doms_cur partition (array of
+ * cpumask) fails, then fallback to a single sched domain,
+ * as determined by the single cpumask fallback_doms.
+ */
+static cpumask_var_t			fallback_doms;
+
+/*
+ * arch_update_cpu_topology lets virtualized architectures update the
+ * CPU core maps. It is supposed to return 1 if the topology changed
+ * or 0 if it stayed the same.
+ */
+int __weak arch_update_cpu_topology(void)
+{
+	return 0;
+}
+
+cpumask_var_t *alloc_sched_domains(unsigned int ndoms)
+{
+	int i;
+	cpumask_var_t *doms;
+
+	doms = kmalloc_array(ndoms, sizeof(*doms), GFP_KERNEL);
+	if (!doms)
+		return NULL;
+	for (i = 0; i < ndoms; i++) {
+		if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) {
+			free_sched_domains(doms, i);
+			return NULL;
+		}
+	}
+	return doms;
+}
+
+void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms)
+{
+	unsigned int i;
+	for (i = 0; i < ndoms; i++)
+		free_cpumask_var(doms[i]);
+	kfree(doms);
+}
+
+/*
+ * Set up scheduler domains and groups.  For now this just excludes isolated
+ * CPUs, but could be used to exclude other special cases in the future.
+ */
+int __init sched_init_domains(const struct cpumask *cpu_map)
+{
+	int err;
+
+	zalloc_cpumask_var(&sched_domains_tmpmask, GFP_KERNEL);
+	zalloc_cpumask_var(&sched_domains_tmpmask2, GFP_KERNEL);
+	zalloc_cpumask_var(&fallback_doms, GFP_KERNEL);
+
+	arch_update_cpu_topology();
+	asym_cpu_capacity_scan();
+	ndoms_cur = 1;
+	doms_cur = alloc_sched_domains(ndoms_cur);
+	if (!doms_cur)
+		doms_cur = &fallback_doms;
+	cpumask_and(doms_cur[0], cpu_map, housekeeping_cpumask(HK_TYPE_DOMAIN));
+	err = build_sched_domains(doms_cur[0], NULL);
+
+	return err;
+}
+
+/*
+ * Detach sched domains from a group of CPUs specified in cpu_map
+ * These CPUs will now be attached to the NULL domain
+ */
+static void detach_destroy_domains(const struct cpumask *cpu_map)
+{
+	unsigned int cpu = cpumask_any(cpu_map);
+	int i;
+
+	if (rcu_access_pointer(per_cpu(sd_asym_cpucapacity, cpu)))
+		static_branch_dec_cpuslocked(&sched_asym_cpucapacity);
+
+	rcu_read_lock();
+	for_each_cpu(i, cpu_map)
+		cpu_attach_domain(NULL, &def_root_domain, i);
+	rcu_read_unlock();
+}
+
+/* handle null as "default" */
+static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
+			struct sched_domain_attr *new, int idx_new)
+{
+	struct sched_domain_attr tmp;
+
+	/* Fast path: */
+	if (!new && !cur)
+		return 1;
+
+	tmp = SD_ATTR_INIT;
+
+	return !memcmp(cur ? (cur + idx_cur) : &tmp,
+			new ? (new + idx_new) : &tmp,
+			sizeof(struct sched_domain_attr));
+}
+
+/*
+ * Partition sched domains as specified by the 'ndoms_new'
+ * cpumasks in the array doms_new[] of cpumasks. This compares
+ * doms_new[] to the current sched domain partitioning, doms_cur[].
+ * It destroys each deleted domain and builds each new domain.
+ *
+ * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
+ * The masks don't intersect (don't overlap.) We should setup one
+ * sched domain for each mask. CPUs not in any of the cpumasks will
+ * not be load balanced. If the same cpumask appears both in the
+ * current 'doms_cur' domains and in the new 'doms_new', we can leave
+ * it as it is.
+ *
+ * The passed in 'doms_new' should be allocated using
+ * alloc_sched_domains.  This routine takes ownership of it and will
+ * free_sched_domains it when done with it. If the caller failed the
+ * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
+ * and partition_sched_domains() will fallback to the single partition
+ * 'fallback_doms', it also forces the domains to be rebuilt.
+ *
+ * If doms_new == NULL it will be replaced with cpu_online_mask.
+ * ndoms_new == 0 is a special case for destroying existing domains,
+ * and it will not create the default domain.
+ *
+ * Call with hotplug lock and sched_domains_mutex held
+ */
+void partition_sched_domains_locked(int ndoms_new, cpumask_var_t doms_new[],
+				    struct sched_domain_attr *dattr_new)
+{
+	bool __maybe_unused has_eas = false;
+	int i, j, n;
+	int new_topology;
+
+	lockdep_assert_held(&sched_domains_mutex);
+
+	/* Let the architecture update CPU core mappings: */
+	new_topology = arch_update_cpu_topology();
+	/* Trigger rebuilding CPU capacity asymmetry data */
+	if (new_topology)
+		asym_cpu_capacity_scan();
+
+	if (!doms_new) {
+		WARN_ON_ONCE(dattr_new);
+		n = 0;
+		doms_new = alloc_sched_domains(1);
+		if (doms_new) {
+			n = 1;
+			cpumask_and(doms_new[0], cpu_active_mask,
+				    housekeeping_cpumask(HK_TYPE_DOMAIN));
+		}
+	} else {
+		n = ndoms_new;
+	}
+
+	/* Destroy deleted domains: */
+	for (i = 0; i < ndoms_cur; i++) {
+		for (j = 0; j < n && !new_topology; j++) {
+			if (cpumask_equal(doms_cur[i], doms_new[j]) &&
+			    dattrs_equal(dattr_cur, i, dattr_new, j)) {
+				struct root_domain *rd;
+
+				/*
+				 * This domain won't be destroyed and as such
+				 * its dl_bw->total_bw needs to be cleared.  It
+				 * will be recomputed in function
+				 * update_tasks_root_domain().
+				 */
+				rd = cpu_rq(cpumask_any(doms_cur[i]))->rd;
+				dl_clear_root_domain(rd);
+				goto match1;
+			}
+		}
+		/* No match - a current sched domain not in new doms_new[] */
+		detach_destroy_domains(doms_cur[i]);
+match1:
+		;
+	}
+
+	n = ndoms_cur;
+	if (!doms_new) {
+		n = 0;
+		doms_new = &fallback_doms;
+		cpumask_and(doms_new[0], cpu_active_mask,
+			    housekeeping_cpumask(HK_TYPE_DOMAIN));
+	}
+
+	/* Build new domains: */
+	for (i = 0; i < ndoms_new; i++) {
+		for (j = 0; j < n && !new_topology; j++) {
+			if (cpumask_equal(doms_new[i], doms_cur[j]) &&
+			    dattrs_equal(dattr_new, i, dattr_cur, j))
+				goto match2;
+		}
+		/* No match - add a new doms_new */
+		build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL);
+match2:
+		;
+	}
+
+#if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
+	/* Build perf. domains: */
+	for (i = 0; i < ndoms_new; i++) {
+		for (j = 0; j < n && !sched_energy_update; j++) {
+			if (cpumask_equal(doms_new[i], doms_cur[j]) &&
+			    cpu_rq(cpumask_first(doms_cur[j]))->rd->pd) {
+				has_eas = true;
+				goto match3;
+			}
+		}
+		/* No match - add perf. domains for a new rd */
+		has_eas |= build_perf_domains(doms_new[i]);
+match3:
+		;
+	}
+	sched_energy_set(has_eas);
+#endif
+
+	/* Remember the new sched domains: */
+	if (doms_cur != &fallback_doms)
+		free_sched_domains(doms_cur, ndoms_cur);
+
+	kfree(dattr_cur);
+	doms_cur = doms_new;
+	dattr_cur = dattr_new;
+	ndoms_cur = ndoms_new;
+
+	update_sched_domain_debugfs();
+}
+
+/*
+ * Call with hotplug lock held
+ */
+void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
+			     struct sched_domain_attr *dattr_new)
+{
+	mutex_lock(&sched_domains_mutex);
+	partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
+	mutex_unlock(&sched_domains_mutex);
+}
diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c
new file mode 100644
index 0000000000..802d98cf2d
--- /dev/null
+++ b/kernel/sched/wait.c
@@ -0,0 +1,486 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Generic waiting primitives.
+ *
+ * (C) 2004 Nadia Yvette Chambers, Oracle
+ */
+
+void __init_waitqueue_head(struct wait_queue_head *wq_head, const char *name, struct lock_class_key *key)
+{
+	spin_lock_init(&wq_head->lock);
+	lockdep_set_class_and_name(&wq_head->lock, key, name);
+	INIT_LIST_HEAD(&wq_head->head);
+}
+
+EXPORT_SYMBOL(__init_waitqueue_head);
+
+void add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
+{
+	unsigned long flags;
+
+	wq_entry->flags &= ~WQ_FLAG_EXCLUSIVE;
+	spin_lock_irqsave(&wq_head->lock, flags);
+	__add_wait_queue(wq_head, wq_entry);
+	spin_unlock_irqrestore(&wq_head->lock, flags);
+}
+EXPORT_SYMBOL(add_wait_queue);
+
+void add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
+{
+	unsigned long flags;
+
+	wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
+	spin_lock_irqsave(&wq_head->lock, flags);
+	__add_wait_queue_entry_tail(wq_head, wq_entry);
+	spin_unlock_irqrestore(&wq_head->lock, flags);
+}
+EXPORT_SYMBOL(add_wait_queue_exclusive);
+
+void add_wait_queue_priority(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
+{
+	unsigned long flags;
+
+	wq_entry->flags |= WQ_FLAG_EXCLUSIVE | WQ_FLAG_PRIORITY;
+	spin_lock_irqsave(&wq_head->lock, flags);
+	__add_wait_queue(wq_head, wq_entry);
+	spin_unlock_irqrestore(&wq_head->lock, flags);
+}
+EXPORT_SYMBOL_GPL(add_wait_queue_priority);
+
+void remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&wq_head->lock, flags);
+	__remove_wait_queue(wq_head, wq_entry);
+	spin_unlock_irqrestore(&wq_head->lock, flags);
+}
+EXPORT_SYMBOL(remove_wait_queue);
+
+/*
+ * Scan threshold to break wait queue walk.
+ * This allows a waker to take a break from holding the
+ * wait queue lock during the wait queue walk.
+ */
+#define WAITQUEUE_WALK_BREAK_CNT 64
+
+/*
+ * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
+ * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
+ * number) then we wake that number of exclusive tasks, and potentially all
+ * the non-exclusive tasks. Normally, exclusive tasks will be at the end of
+ * the list and any non-exclusive tasks will be woken first. A priority task
+ * may be at the head of the list, and can consume the event without any other
+ * tasks being woken.
+ *
+ * There are circumstances in which we can try to wake a task which has already
+ * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
+ * zero in this (rare) case, and we handle it by continuing to scan the queue.
+ */
+static int __wake_up_common(struct wait_queue_head *wq_head, unsigned int mode,
+			int nr_exclusive, int wake_flags, void *key,
+			wait_queue_entry_t *bookmark)
+{
+	wait_queue_entry_t *curr, *next;
+	int cnt = 0;
+
+	lockdep_assert_held(&wq_head->lock);
+
+	if (bookmark && (bookmark->flags & WQ_FLAG_BOOKMARK)) {
+		curr = list_next_entry(bookmark, entry);
+
+		list_del(&bookmark->entry);
+		bookmark->flags = 0;
+	} else
+		curr = list_first_entry(&wq_head->head, wait_queue_entry_t, entry);
+
+	if (&curr->entry == &wq_head->head)
+		return nr_exclusive;
+
+	list_for_each_entry_safe_from(curr, next, &wq_head->head, entry) {
+		unsigned flags = curr->flags;
+		int ret;
+
+		if (flags & WQ_FLAG_BOOKMARK)
+			continue;
+
+		ret = curr->func(curr, mode, wake_flags, key);
+		if (ret < 0)
+			break;
+		if (ret && (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
+			break;
+
+		if (bookmark && (++cnt > WAITQUEUE_WALK_BREAK_CNT) &&
+				(&next->entry != &wq_head->head)) {
+			bookmark->flags = WQ_FLAG_BOOKMARK;
+			list_add_tail(&bookmark->entry, &next->entry);
+			break;
+		}
+	}
+
+	return nr_exclusive;
+}
+
+static int __wake_up_common_lock(struct wait_queue_head *wq_head, unsigned int mode,
+			int nr_exclusive, int wake_flags, void *key)
+{
+	unsigned long flags;
+	wait_queue_entry_t bookmark;
+	int remaining = nr_exclusive;
+
+	bookmark.flags = 0;
+	bookmark.private = NULL;
+	bookmark.func = NULL;
+	INIT_LIST_HEAD(&bookmark.entry);
+
+	do {
+		spin_lock_irqsave(&wq_head->lock, flags);
+		remaining = __wake_up_common(wq_head, mode, remaining,
+						wake_flags, key, &bookmark);
+		spin_unlock_irqrestore(&wq_head->lock, flags);
+	} while (bookmark.flags & WQ_FLAG_BOOKMARK);
+
+	return nr_exclusive - remaining;
+}
+
+/**
+ * __wake_up - wake up threads blocked on a waitqueue.
+ * @wq_head: the waitqueue
+ * @mode: which threads
+ * @nr_exclusive: how many wake-one or wake-many threads to wake up
+ * @key: is directly passed to the wakeup function
+ *
+ * If this function wakes up a task, it executes a full memory barrier
+ * before accessing the task state.  Returns the number of exclusive
+ * tasks that were awaken.
+ */
+int __wake_up(struct wait_queue_head *wq_head, unsigned int mode,
+	      int nr_exclusive, void *key)
+{
+	return __wake_up_common_lock(wq_head, mode, nr_exclusive, 0, key);
+}
+EXPORT_SYMBOL(__wake_up);
+
+void __wake_up_on_current_cpu(struct wait_queue_head *wq_head, unsigned int mode, void *key)
+{
+	__wake_up_common_lock(wq_head, mode, 1, WF_CURRENT_CPU, key);
+}
+
+/*
+ * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
+ */
+void __wake_up_locked(struct wait_queue_head *wq_head, unsigned int mode, int nr)
+{
+	__wake_up_common(wq_head, mode, nr, 0, NULL, NULL);
+}
+EXPORT_SYMBOL_GPL(__wake_up_locked);
+
+void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, void *key)
+{
+	__wake_up_common(wq_head, mode, 1, 0, key, NULL);
+}
+EXPORT_SYMBOL_GPL(__wake_up_locked_key);
+
+void __wake_up_locked_key_bookmark(struct wait_queue_head *wq_head,
+		unsigned int mode, void *key, wait_queue_entry_t *bookmark)
+{
+	__wake_up_common(wq_head, mode, 1, 0, key, bookmark);
+}
+EXPORT_SYMBOL_GPL(__wake_up_locked_key_bookmark);
+
+/**
+ * __wake_up_sync_key - wake up threads blocked on a waitqueue.
+ * @wq_head: the waitqueue
+ * @mode: which threads
+ * @key: opaque value to be passed to wakeup targets
+ *
+ * The sync wakeup differs that the waker knows that it will schedule
+ * away soon, so while the target thread will be woken up, it will not
+ * be migrated to another CPU - ie. the two threads are 'synchronized'
+ * with each other. This can prevent needless bouncing between CPUs.
+ *
+ * On UP it can prevent extra preemption.
+ *
+ * If this function wakes up a task, it executes a full memory barrier before
+ * accessing the task state.
+ */
+void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode,
+			void *key)
+{
+	if (unlikely(!wq_head))
+		return;
+
+	__wake_up_common_lock(wq_head, mode, 1, WF_SYNC, key);
+}
+EXPORT_SYMBOL_GPL(__wake_up_sync_key);
+
+/**
+ * __wake_up_locked_sync_key - wake up a thread blocked on a locked waitqueue.
+ * @wq_head: the waitqueue
+ * @mode: which threads
+ * @key: opaque value to be passed to wakeup targets
+ *
+ * The sync wakeup differs in that the waker knows that it will schedule
+ * away soon, so while the target thread will be woken up, it will not
+ * be migrated to another CPU - ie. the two threads are 'synchronized'
+ * with each other. This can prevent needless bouncing between CPUs.
+ *
+ * On UP it can prevent extra preemption.
+ *
+ * If this function wakes up a task, it executes a full memory barrier before
+ * accessing the task state.
+ */
+void __wake_up_locked_sync_key(struct wait_queue_head *wq_head,
+			       unsigned int mode, void *key)
+{
+        __wake_up_common(wq_head, mode, 1, WF_SYNC, key, NULL);
+}
+EXPORT_SYMBOL_GPL(__wake_up_locked_sync_key);
+
+/*
+ * __wake_up_sync - see __wake_up_sync_key()
+ */
+void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode)
+{
+	__wake_up_sync_key(wq_head, mode, NULL);
+}
+EXPORT_SYMBOL_GPL(__wake_up_sync);	/* For internal use only */
+
+void __wake_up_pollfree(struct wait_queue_head *wq_head)
+{
+	__wake_up(wq_head, TASK_NORMAL, 0, poll_to_key(EPOLLHUP | POLLFREE));
+	/* POLLFREE must have cleared the queue. */
+	WARN_ON_ONCE(waitqueue_active(wq_head));
+}
+
+/*
+ * Note: we use "set_current_state()" _after_ the wait-queue add,
+ * because we need a memory barrier there on SMP, so that any
+ * wake-function that tests for the wait-queue being active
+ * will be guaranteed to see waitqueue addition _or_ subsequent
+ * tests in this thread will see the wakeup having taken place.
+ *
+ * The spin_unlock() itself is semi-permeable and only protects
+ * one way (it only protects stuff inside the critical region and
+ * stops them from bleeding out - it would still allow subsequent
+ * loads to move into the critical region).
+ */
+void
+prepare_to_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state)
+{
+	unsigned long flags;
+
+	wq_entry->flags &= ~WQ_FLAG_EXCLUSIVE;
+	spin_lock_irqsave(&wq_head->lock, flags);
+	if (list_empty(&wq_entry->entry))
+		__add_wait_queue(wq_head, wq_entry);
+	set_current_state(state);
+	spin_unlock_irqrestore(&wq_head->lock, flags);
+}
+EXPORT_SYMBOL(prepare_to_wait);
+
+/* Returns true if we are the first waiter in the queue, false otherwise. */
+bool
+prepare_to_wait_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state)
+{
+	unsigned long flags;
+	bool was_empty = false;
+
+	wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
+	spin_lock_irqsave(&wq_head->lock, flags);
+	if (list_empty(&wq_entry->entry)) {
+		was_empty = list_empty(&wq_head->head);
+		__add_wait_queue_entry_tail(wq_head, wq_entry);
+	}
+	set_current_state(state);
+	spin_unlock_irqrestore(&wq_head->lock, flags);
+	return was_empty;
+}
+EXPORT_SYMBOL(prepare_to_wait_exclusive);
+
+void init_wait_entry(struct wait_queue_entry *wq_entry, int flags)
+{
+	wq_entry->flags = flags;
+	wq_entry->private = current;
+	wq_entry->func = autoremove_wake_function;
+	INIT_LIST_HEAD(&wq_entry->entry);
+}
+EXPORT_SYMBOL(init_wait_entry);
+
+long prepare_to_wait_event(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state)
+{
+	unsigned long flags;
+	long ret = 0;
+
+	spin_lock_irqsave(&wq_head->lock, flags);
+	if (signal_pending_state(state, current)) {
+		/*
+		 * Exclusive waiter must not fail if it was selected by wakeup,
+		 * it should "consume" the condition we were waiting for.
+		 *
+		 * The caller will recheck the condition and return success if
+		 * we were already woken up, we can not miss the event because
+		 * wakeup locks/unlocks the same wq_head->lock.
+		 *
+		 * But we need to ensure that set-condition + wakeup after that
+		 * can't see us, it should wake up another exclusive waiter if
+		 * we fail.
+		 */
+		list_del_init(&wq_entry->entry);
+		ret = -ERESTARTSYS;
+	} else {
+		if (list_empty(&wq_entry->entry)) {
+			if (wq_entry->flags & WQ_FLAG_EXCLUSIVE)
+				__add_wait_queue_entry_tail(wq_head, wq_entry);
+			else
+				__add_wait_queue(wq_head, wq_entry);
+		}
+		set_current_state(state);
+	}
+	spin_unlock_irqrestore(&wq_head->lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(prepare_to_wait_event);
+
+/*
+ * Note! These two wait functions are entered with the
+ * wait-queue lock held (and interrupts off in the _irq
+ * case), so there is no race with testing the wakeup
+ * condition in the caller before they add the wait
+ * entry to the wake queue.
+ */
+int do_wait_intr(wait_queue_head_t *wq, wait_queue_entry_t *wait)
+{
+	if (likely(list_empty(&wait->entry)))
+		__add_wait_queue_entry_tail(wq, wait);
+
+	set_current_state(TASK_INTERRUPTIBLE);
+	if (signal_pending(current))
+		return -ERESTARTSYS;
+
+	spin_unlock(&wq->lock);
+	schedule();
+	spin_lock(&wq->lock);
+
+	return 0;
+}
+EXPORT_SYMBOL(do_wait_intr);
+
+int do_wait_intr_irq(wait_queue_head_t *wq, wait_queue_entry_t *wait)
+{
+	if (likely(list_empty(&wait->entry)))
+		__add_wait_queue_entry_tail(wq, wait);
+
+	set_current_state(TASK_INTERRUPTIBLE);
+	if (signal_pending(current))
+		return -ERESTARTSYS;
+
+	spin_unlock_irq(&wq->lock);
+	schedule();
+	spin_lock_irq(&wq->lock);
+
+	return 0;
+}
+EXPORT_SYMBOL(do_wait_intr_irq);
+
+/**
+ * finish_wait - clean up after waiting in a queue
+ * @wq_head: waitqueue waited on
+ * @wq_entry: wait descriptor
+ *
+ * Sets current thread back to running state and removes
+ * the wait descriptor from the given waitqueue if still
+ * queued.
+ */
+void finish_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
+{
+	unsigned long flags;
+
+	__set_current_state(TASK_RUNNING);
+	/*
+	 * We can check for list emptiness outside the lock
+	 * IFF:
+	 *  - we use the "careful" check that verifies both
+	 *    the next and prev pointers, so that there cannot
+	 *    be any half-pending updates in progress on other
+	 *    CPU's that we haven't seen yet (and that might
+	 *    still change the stack area.
+	 * and
+	 *  - all other users take the lock (ie we can only
+	 *    have _one_ other CPU that looks at or modifies
+	 *    the list).
+	 */
+	if (!list_empty_careful(&wq_entry->entry)) {
+		spin_lock_irqsave(&wq_head->lock, flags);
+		list_del_init(&wq_entry->entry);
+		spin_unlock_irqrestore(&wq_head->lock, flags);
+	}
+}
+EXPORT_SYMBOL(finish_wait);
+
+int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key)
+{
+	int ret = default_wake_function(wq_entry, mode, sync, key);
+
+	if (ret)
+		list_del_init_careful(&wq_entry->entry);
+
+	return ret;
+}
+EXPORT_SYMBOL(autoremove_wake_function);
+
+/*
+ * DEFINE_WAIT_FUNC(wait, woken_wake_func);
+ *
+ * add_wait_queue(&wq_head, &wait);
+ * for (;;) {
+ *     if (condition)
+ *         break;
+ *
+ *     // in wait_woken()			// in woken_wake_function()
+ *
+ *     p->state = mode;				wq_entry->flags |= WQ_FLAG_WOKEN;
+ *     smp_mb(); // A				try_to_wake_up():
+ *     if (!(wq_entry->flags & WQ_FLAG_WOKEN))	   <full barrier>
+ *         schedule()				   if (p->state & mode)
+ *     p->state = TASK_RUNNING;			      p->state = TASK_RUNNING;
+ *     wq_entry->flags &= ~WQ_FLAG_WOKEN;	~~~~~~~~~~~~~~~~~~
+ *     smp_mb(); // B				condition = true;
+ * }						smp_mb(); // C
+ * remove_wait_queue(&wq_head, &wait);		wq_entry->flags |= WQ_FLAG_WOKEN;
+ */
+long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout)
+{
+	/*
+	 * The below executes an smp_mb(), which matches with the full barrier
+	 * executed by the try_to_wake_up() in woken_wake_function() such that
+	 * either we see the store to wq_entry->flags in woken_wake_function()
+	 * or woken_wake_function() sees our store to current->state.
+	 */
+	set_current_state(mode); /* A */
+	if (!(wq_entry->flags & WQ_FLAG_WOKEN) && !kthread_should_stop_or_park())
+		timeout = schedule_timeout(timeout);
+	__set_current_state(TASK_RUNNING);
+
+	/*
+	 * The below executes an smp_mb(), which matches with the smp_mb() (C)
+	 * in woken_wake_function() such that either we see the wait condition
+	 * being true or the store to wq_entry->flags in woken_wake_function()
+	 * follows ours in the coherence order.
+	 */
+	smp_store_mb(wq_entry->flags, wq_entry->flags & ~WQ_FLAG_WOKEN); /* B */
+
+	return timeout;
+}
+EXPORT_SYMBOL(wait_woken);
+
+int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key)
+{
+	/* Pairs with the smp_store_mb() in wait_woken(). */
+	smp_mb(); /* C */
+	wq_entry->flags |= WQ_FLAG_WOKEN;
+
+	return default_wake_function(wq_entry, mode, sync, key);
+}
+EXPORT_SYMBOL(woken_wake_function);
diff --git a/kernel/sched/wait_bit.c b/kernel/sched/wait_bit.c
new file mode 100644
index 0000000000..0b1cd985dc
--- /dev/null
+++ b/kernel/sched/wait_bit.c
@@ -0,0 +1,251 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ * The implementation of the wait_bit*() and related waiting APIs:
+ */
+
+#define WAIT_TABLE_BITS 8
+#define WAIT_TABLE_SIZE (1 << WAIT_TABLE_BITS)
+
+static wait_queue_head_t bit_wait_table[WAIT_TABLE_SIZE] __cacheline_aligned;
+
+wait_queue_head_t *bit_waitqueue(void *word, int bit)
+{
+	const int shift = BITS_PER_LONG == 32 ? 5 : 6;
+	unsigned long val = (unsigned long)word << shift | bit;
+
+	return bit_wait_table + hash_long(val, WAIT_TABLE_BITS);
+}
+EXPORT_SYMBOL(bit_waitqueue);
+
+int wake_bit_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *arg)
+{
+	struct wait_bit_key *key = arg;
+	struct wait_bit_queue_entry *wait_bit = container_of(wq_entry, struct wait_bit_queue_entry, wq_entry);
+
+	if (wait_bit->key.flags != key->flags ||
+			wait_bit->key.bit_nr != key->bit_nr ||
+			test_bit(key->bit_nr, key->flags))
+		return 0;
+
+	return autoremove_wake_function(wq_entry, mode, sync, key);
+}
+EXPORT_SYMBOL(wake_bit_function);
+
+/*
+ * To allow interruptible waiting and asynchronous (i.e. nonblocking)
+ * waiting, the actions of __wait_on_bit() and __wait_on_bit_lock() are
+ * permitted return codes. Nonzero return codes halt waiting and return.
+ */
+int __sched
+__wait_on_bit(struct wait_queue_head *wq_head, struct wait_bit_queue_entry *wbq_entry,
+	      wait_bit_action_f *action, unsigned mode)
+{
+	int ret = 0;
+
+	do {
+		prepare_to_wait(wq_head, &wbq_entry->wq_entry, mode);
+		if (test_bit(wbq_entry->key.bit_nr, wbq_entry->key.flags))
+			ret = (*action)(&wbq_entry->key, mode);
+	} while (test_bit_acquire(wbq_entry->key.bit_nr, wbq_entry->key.flags) && !ret);
+
+	finish_wait(wq_head, &wbq_entry->wq_entry);
+
+	return ret;
+}
+EXPORT_SYMBOL(__wait_on_bit);
+
+int __sched out_of_line_wait_on_bit(void *word, int bit,
+				    wait_bit_action_f *action, unsigned mode)
+{
+	struct wait_queue_head *wq_head = bit_waitqueue(word, bit);
+	DEFINE_WAIT_BIT(wq_entry, word, bit);
+
+	return __wait_on_bit(wq_head, &wq_entry, action, mode);
+}
+EXPORT_SYMBOL(out_of_line_wait_on_bit);
+
+int __sched out_of_line_wait_on_bit_timeout(
+	void *word, int bit, wait_bit_action_f *action,
+	unsigned mode, unsigned long timeout)
+{
+	struct wait_queue_head *wq_head = bit_waitqueue(word, bit);
+	DEFINE_WAIT_BIT(wq_entry, word, bit);
+
+	wq_entry.key.timeout = jiffies + timeout;
+
+	return __wait_on_bit(wq_head, &wq_entry, action, mode);
+}
+EXPORT_SYMBOL_GPL(out_of_line_wait_on_bit_timeout);
+
+int __sched
+__wait_on_bit_lock(struct wait_queue_head *wq_head, struct wait_bit_queue_entry *wbq_entry,
+			wait_bit_action_f *action, unsigned mode)
+{
+	int ret = 0;
+
+	for (;;) {
+		prepare_to_wait_exclusive(wq_head, &wbq_entry->wq_entry, mode);
+		if (test_bit(wbq_entry->key.bit_nr, wbq_entry->key.flags)) {
+			ret = action(&wbq_entry->key, mode);
+			/*
+			 * See the comment in prepare_to_wait_event().
+			 * finish_wait() does not necessarily takes wwq_head->lock,
+			 * but test_and_set_bit() implies mb() which pairs with
+			 * smp_mb__after_atomic() before wake_up_page().
+			 */
+			if (ret)
+				finish_wait(wq_head, &wbq_entry->wq_entry);
+		}
+		if (!test_and_set_bit(wbq_entry->key.bit_nr, wbq_entry->key.flags)) {
+			if (!ret)
+				finish_wait(wq_head, &wbq_entry->wq_entry);
+			return 0;
+		} else if (ret) {
+			return ret;
+		}
+	}
+}
+EXPORT_SYMBOL(__wait_on_bit_lock);
+
+int __sched out_of_line_wait_on_bit_lock(void *word, int bit,
+					 wait_bit_action_f *action, unsigned mode)
+{
+	struct wait_queue_head *wq_head = bit_waitqueue(word, bit);
+	DEFINE_WAIT_BIT(wq_entry, word, bit);
+
+	return __wait_on_bit_lock(wq_head, &wq_entry, action, mode);
+}
+EXPORT_SYMBOL(out_of_line_wait_on_bit_lock);
+
+void __wake_up_bit(struct wait_queue_head *wq_head, void *word, int bit)
+{
+	struct wait_bit_key key = __WAIT_BIT_KEY_INITIALIZER(word, bit);
+
+	if (waitqueue_active(wq_head))
+		__wake_up(wq_head, TASK_NORMAL, 1, &key);
+}
+EXPORT_SYMBOL(__wake_up_bit);
+
+/**
+ * wake_up_bit - wake up a waiter on a bit
+ * @word: the word being waited on, a kernel virtual address
+ * @bit: the bit of the word being waited on
+ *
+ * There is a standard hashed waitqueue table for generic use. This
+ * is the part of the hashtable's accessor API that wakes up waiters
+ * on a bit. For instance, if one were to have waiters on a bitflag,
+ * one would call wake_up_bit() after clearing the bit.
+ *
+ * In order for this to function properly, as it uses waitqueue_active()
+ * internally, some kind of memory barrier must be done prior to calling
+ * this. Typically, this will be smp_mb__after_atomic(), but in some
+ * cases where bitflags are manipulated non-atomically under a lock, one
+ * may need to use a less regular barrier, such fs/inode.c's smp_mb(),
+ * because spin_unlock() does not guarantee a memory barrier.
+ */
+void wake_up_bit(void *word, int bit)
+{
+	__wake_up_bit(bit_waitqueue(word, bit), word, bit);
+}
+EXPORT_SYMBOL(wake_up_bit);
+
+wait_queue_head_t *__var_waitqueue(void *p)
+{
+	return bit_wait_table + hash_ptr(p, WAIT_TABLE_BITS);
+}
+EXPORT_SYMBOL(__var_waitqueue);
+
+static int
+var_wake_function(struct wait_queue_entry *wq_entry, unsigned int mode,
+		  int sync, void *arg)
+{
+	struct wait_bit_key *key = arg;
+	struct wait_bit_queue_entry *wbq_entry =
+		container_of(wq_entry, struct wait_bit_queue_entry, wq_entry);
+
+	if (wbq_entry->key.flags != key->flags ||
+	    wbq_entry->key.bit_nr != key->bit_nr)
+		return 0;
+
+	return autoremove_wake_function(wq_entry, mode, sync, key);
+}
+
+void init_wait_var_entry(struct wait_bit_queue_entry *wbq_entry, void *var, int flags)
+{
+	*wbq_entry = (struct wait_bit_queue_entry){
+		.key = {
+			.flags	= (var),
+			.bit_nr = -1,
+		},
+		.wq_entry = {
+			.flags	 = flags,
+			.private = current,
+			.func	 = var_wake_function,
+			.entry	 = LIST_HEAD_INIT(wbq_entry->wq_entry.entry),
+		},
+	};
+}
+EXPORT_SYMBOL(init_wait_var_entry);
+
+void wake_up_var(void *var)
+{
+	__wake_up_bit(__var_waitqueue(var), var, -1);
+}
+EXPORT_SYMBOL(wake_up_var);
+
+__sched int bit_wait(struct wait_bit_key *word, int mode)
+{
+	schedule();
+	if (signal_pending_state(mode, current))
+		return -EINTR;
+
+	return 0;
+}
+EXPORT_SYMBOL(bit_wait);
+
+__sched int bit_wait_io(struct wait_bit_key *word, int mode)
+{
+	io_schedule();
+	if (signal_pending_state(mode, current))
+		return -EINTR;
+
+	return 0;
+}
+EXPORT_SYMBOL(bit_wait_io);
+
+__sched int bit_wait_timeout(struct wait_bit_key *word, int mode)
+{
+	unsigned long now = READ_ONCE(jiffies);
+
+	if (time_after_eq(now, word->timeout))
+		return -EAGAIN;
+	schedule_timeout(word->timeout - now);
+	if (signal_pending_state(mode, current))
+		return -EINTR;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(bit_wait_timeout);
+
+__sched int bit_wait_io_timeout(struct wait_bit_key *word, int mode)
+{
+	unsigned long now = READ_ONCE(jiffies);
+
+	if (time_after_eq(now, word->timeout))
+		return -EAGAIN;
+	io_schedule_timeout(word->timeout - now);
+	if (signal_pending_state(mode, current))
+		return -EINTR;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(bit_wait_io_timeout);
+
+void __init wait_bit_init(void)
+{
+	int i;
+
+	for (i = 0; i < WAIT_TABLE_SIZE; i++)
+		init_waitqueue_head(bit_wait_table + i);
+}