Adding upstream version 4.19.249.upstream/4.19.249upstream

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

1 files changed, 2793 insertions, 0 deletions

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
new file mode 100644
index 000000000..beec5081a
--- /dev/null
+++ b/kernel/sched/deadline.c
@@ -0,0 +1,2793 @@
+// 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 "sched.h"
+#include "pelt.h"
+
+struct dl_bandwidth def_dl_bandwidth;
+
+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_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 = 0;
+
+	RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(),
+			 "sched RCU must be held");
+	for_each_cpu_and(i, rd->span, cpu_active_mask)
+		cpus++;
+
+	return cpus;
+}
+#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;
+}
+#endif
+
+static inline
+void __add_running_bw(u64 dl_bw, struct dl_rq *dl_rq)
+{
+	u64 old = dl_rq->running_bw;
+
+	lockdep_assert_held(&(rq_of_dl_rq(dl_rq))->lock);
+	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_held(&(rq_of_dl_rq(dl_rq))->lock);
+	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_held(&(rq_of_dl_rq(dl_rq))->lock);
+	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_held(&(rq_of_dl_rq(dl_rq))->lock);
+	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);
+}
+
+void dl_change_utilization(struct task_struct *p, u64 new_bw)
+{
+	struct rq *rq;
+
+	BUG_ON(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 cancelled, 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 cancelled, 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) || p->state == TASK_DEAD) {
+			struct dl_bw *dl_b = dl_bw_of(task_cpu(p));
+
+			if (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)));
+			__dl_clear_params(p);
+			raw_spin_unlock(&dl_b->lock);
+		}
+
+		return;
+	}
+
+	dl_se->dl_non_contending = 1;
+	get_task_struct(p);
+	hrtimer_start(timer, ns_to_ktime(zerolag_time), HRTIMER_MODE_REL);
+}
+
+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 cancelled, 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 dl_rq->root.rb_leftmost == &dl_se->rb_node;
+}
+
+void init_dl_bandwidth(struct dl_bandwidth *dl_b, u64 period, u64 runtime)
+{
+	raw_spin_lock_init(&dl_b->dl_runtime_lock);
+	dl_b->dl_period = period;
+	dl_b->dl_runtime = runtime;
+}
+
+void init_dl_bw(struct dl_bw *dl_b)
+{
+	raw_spin_lock_init(&dl_b->lock);
+	raw_spin_lock(&def_dl_bandwidth.dl_runtime_lock);
+	if (global_rt_runtime() == RUNTIME_INF)
+		dl_b->bw = -1;
+	else
+		dl_b->bw = to_ratio(global_rt_period(), global_rt_runtime());
+	raw_spin_unlock(&def_dl_bandwidth.dl_runtime_lock);
+	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);
+}
+
+/*
+ * 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 dl_rq *dl_rq = &rq->dl;
+	struct rb_node **link = &dl_rq->pushable_dl_tasks_root.rb_root.rb_node;
+	struct rb_node *parent = NULL;
+	struct task_struct *entry;
+	bool leftmost = true;
+
+	BUG_ON(!RB_EMPTY_NODE(&p->pushable_dl_tasks));
+
+	while (*link) {
+		parent = *link;
+		entry = rb_entry(parent, struct task_struct,
+				 pushable_dl_tasks);
+		if (dl_entity_preempt(&p->dl, &entry->dl))
+			link = &parent->rb_left;
+		else {
+			link = &parent->rb_right;
+			leftmost = false;
+		}
+	}
+
+	if (leftmost)
+		dl_rq->earliest_dl.next = p->dl.deadline;
+
+	rb_link_node(&p->pushable_dl_tasks, parent, link);
+	rb_insert_color_cached(&p->pushable_dl_tasks,
+			       &dl_rq->pushable_dl_tasks_root, leftmost);
+}
+
+static void dequeue_pushable_dl_task(struct rq *rq, struct task_struct *p)
+{
+	struct dl_rq *dl_rq = &rq->dl;
+
+	if (RB_EMPTY_NODE(&p->pushable_dl_tasks))
+		return;
+
+	if (dl_rq->pushable_dl_tasks_root.rb_leftmost == &p->pushable_dl_tasks) {
+		struct rb_node *next_node;
+
+		next_node = rb_next(&p->pushable_dl_tasks);
+		if (next_node) {
+			dl_rq->earliest_dl.next = rb_entry(next_node,
+				struct task_struct, pushable_dl_tasks)->dl.deadline;
+		}
+	}
+
+	rb_erase_cached(&p->pushable_dl_tasks, &dl_rq->pushable_dl_tasks_root);
+	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 dl_task(prev);
+}
+
+static DEFINE_PER_CPU(struct callback_head, dl_push_head);
+static DEFINE_PER_CPU(struct callback_head, 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_allowed);
+		if (cpu >= nr_cpu_ids) {
+			/*
+			 * Failed to find any suitable CPU.
+			 * The task will never come back!
+			 */
+			BUG_ON(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 bool need_pull_dl_task(struct rq *rq, struct task_struct *prev)
+{
+	return false;
+}
+
+static inline void pull_dl_task(struct rq *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);
+
+/*
+ * 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(dl_se->dl_boosted);
+	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.).
+	 */
+	dl_se->deadline = rq_clock(rq) + dl_se->dl_deadline;
+	dl_se->runtime = dl_se->dl_runtime;
+}
+
+/*
+ * 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 sched_dl_entity *pi_se)
+{
+	struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
+	struct rq *rq = rq_of_dl_rq(dl_rq);
+
+	BUG_ON(pi_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) {
+		dl_se->deadline = rq_clock(rq) + pi_se->dl_deadline;
+		dl_se->runtime = pi_se->dl_runtime;
+	}
+
+	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_se->dl_period;
+		dl_se->runtime += pi_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");
+		dl_se->deadline = rq_clock(rq) + pi_se->dl_deadline;
+		dl_se->runtime = pi_se->dl_runtime;
+	}
+
+	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.txt for more informations).
+ *
+ * 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,
+			       struct sched_dl_entity *pi_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_se->dl_deadline >> DL_SCALE) * (dl_se->runtime >> DL_SCALE);
+	right = ((dl_se->deadline - t) >> DL_SCALE) *
+		(pi_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 sched_dl_entity *pi_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, pi_se, rq_clock(rq))) {
+
+		if (unlikely(!dl_is_implicit(dl_se) &&
+			     !dl_time_before(dl_se->deadline, rq_clock(rq)) &&
+			     !dl_se->dl_boosted)){
+			update_dl_revised_wakeup(dl_se, rq);
+			return;
+		}
+
+		dl_se->deadline = rq_clock(rq) + pi_se->dl_deadline;
+		dl_se->runtime = pi_se->dl_runtime;
+	}
+}
+
+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_held(&rq->lock);
+
+	/*
+	 * 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);
+	}
+
+	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 (dl_se->dl_boosted)
+		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, 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->lock, rf.cookie);
+		rq = dl_task_offline_migration(rq, p);
+		rf.cookie = lockdep_pin_lock(&rq->lock);
+		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);
+	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 (deadine < 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(dl_se->dl_boosted || !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);
+}
+
+extern bool sched_rt_bandwidth_account(struct rt_rq *rt_rq);
+
+/*
+ * 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, (1 - Uinact - Uextra)} 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 multipled 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_inact = rq->dl.this_bw - rq->dl.running_bw; /* Utot - Uact */
+	u64 u_act;
+	u64 u_act_min = (dl_se->dl_bw * rq->dl.bw_ratio) >> RATIO_SHIFT;
+
+	/*
+	 * Instead of computing max{u * bw_ratio, (1 - u_inact - u_extra)},
+	 * we compare u_inact + rq->dl.extra_bw with
+	 * 1 - (u * rq->dl.bw_ratio >> RATIO_SHIFT), because
+	 * u_inact + rq->dl.extra_bw can be larger than
+	 * 1 * (so, 1 - u_inact - rq->dl.extra_bw would be negative
+	 * leading to wrong results)
+	 */
+	if (u_inact + rq->dl.extra_bw > BW_UNIT - u_act_min)
+		u_act = u_act_min;
+	else
+		u_act = BW_UNIT - u_inact - rq->dl.extra_bw;
+
+	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->se.statistics.exec_max,
+		      max(curr->se.statistics.exec_max, 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);
+
+	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(NULL, 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(dl_se->dl_boosted || !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) || p->state == TASK_DEAD) {
+		struct dl_bw *dl_b = dl_bw_of(task_cpu(p));
+
+		if (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);
+	timer->function = inactive_task_timer;
+}
+
+#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)) {
+		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);
+	} else {
+		struct rb_node *leftmost = dl_rq->root.rb_leftmost;
+		struct sched_dl_entity *entry;
+
+		entry = rb_entry(leftmost, struct sched_dl_entity, rb_node);
+		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 void __enqueue_dl_entity(struct sched_dl_entity *dl_se)
+{
+	struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
+	struct rb_node **link = &dl_rq->root.rb_root.rb_node;
+	struct rb_node *parent = NULL;
+	struct sched_dl_entity *entry;
+	int leftmost = 1;
+
+	BUG_ON(!RB_EMPTY_NODE(&dl_se->rb_node));
+
+	while (*link) {
+		parent = *link;
+		entry = rb_entry(parent, struct sched_dl_entity, rb_node);
+		if (dl_time_before(dl_se->deadline, entry->deadline))
+			link = &parent->rb_left;
+		else {
+			link = &parent->rb_right;
+			leftmost = 0;
+		}
+	}
+
+	rb_link_node(&dl_se->rb_node, parent, link);
+	rb_insert_color_cached(&dl_se->rb_node, &dl_rq->root, leftmost);
+
+	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,
+		  struct sched_dl_entity *pi_se, int flags)
+{
+	BUG_ON(on_dl_rq(dl_se));
+
+	/*
+	 * 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, pi_se);
+	} else if (flags & ENQUEUE_REPLENISH) {
+		replenish_dl_entity(dl_se, pi_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)
+{
+	struct task_struct *pi_task = rt_mutex_get_top_task(p);
+	struct sched_dl_entity *pi_se = &p->dl;
+
+	/*
+	 * Use the scheduling parameters of the top pi-waiter task if:
+	 * - we have a top pi-waiter which is a SCHED_DEADLINE task AND
+	 * - our dl_boosted is set (i.e. the pi-waiter's (absolute) deadline is
+	 *   smaller than our deadline OR we are a !SCHED_DEADLINE task getting
+	 *   boosted due to a SCHED_DEADLINE pi-waiter).
+	 * Otherwise we keep our runtime and deadline.
+	 */
+	if (pi_task && dl_prio(pi_task->normal_prio) && p->dl.dl_boosted) {
+		pi_se = &pi_task->dl;
+	} 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.
+		 */
+		BUG_ON(!p->dl.dl_boosted || flags != ENQUEUE_REPLENISH);
+		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;
+	}
+
+	enqueue_dl_entity(&p->dl, pi_se, 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)
+{
+	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 int find_later_rq(struct task_struct *task);
+
+static int
+select_task_rq_dl(struct task_struct *p, int cpu, int sd_flag, int flags)
+{
+	struct task_struct *curr;
+	struct rq *rq;
+
+	if (sd_flag != SD_BALANCE_WAKE)
+		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.
+	 */
+	if (unlikely(dl_task(curr)) &&
+	    (curr->nr_cpus_allowed < 2 ||
+	     !dl_entity_preempt(&p->dl, &curr->dl)) &&
+	    (p->nr_cpus_allowed > 1)) {
+		int target = find_later_rq(p);
+
+		if (target != -1 &&
+				(dl_time_before(p->dl.deadline,
+					cpu_rq(target)->dl.earliest_dl.curr) ||
+				(cpu_rq(target)->dl.dl_nr_running == 0)))
+			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 *rq;
+
+	if (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
+	 */
+	raw_spin_lock(&rq->lock);
+	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 cancelled, 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);
+	raw_spin_unlock(&rq->lock);
+}
+
+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);
+}
+
+#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 struct sched_dl_entity *pick_next_dl_entity(struct rq *rq,
+						   struct dl_rq *dl_rq)
+{
+	struct rb_node *left = rb_first_cached(&dl_rq->root);
+
+	if (!left)
+		return NULL;
+
+	return rb_entry(left, struct sched_dl_entity, rb_node);
+}
+
+static struct task_struct *
+pick_next_task_dl(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
+{
+	struct sched_dl_entity *dl_se;
+	struct task_struct *p;
+	struct dl_rq *dl_rq;
+
+	dl_rq = &rq->dl;
+
+	if (need_pull_dl_task(rq, prev)) {
+		/*
+		 * 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(rq, rf);
+		pull_dl_task(rq);
+		rq_repin_lock(rq, rf);
+		/*
+		 * pull_dl_task() can drop (and re-acquire) rq->lock; this
+		 * means a stop task can slip in, in which case we need to
+		 * re-start task selection.
+		 */
+		if (rq->stop && task_on_rq_queued(rq->stop))
+			return RETRY_TASK;
+	}
+
+	/*
+	 * When prev is DL, we may throttle it in put_prev_task().
+	 * So, we update time before we check for dl_nr_running.
+	 */
+	if (prev->sched_class == &dl_sched_class)
+		update_curr_dl(rq);
+
+	if (unlikely(!dl_rq->dl_nr_running))
+		return NULL;
+
+	put_prev_task(rq, prev);
+
+	dl_se = pick_next_dl_entity(rq, dl_rq);
+	BUG_ON(!dl_se);
+
+	p = dl_task_of(dl_se);
+	p->se.exec_start = rq_clock_task(rq);
+
+	/* Running task will never be pushed. */
+       dequeue_pushable_dl_task(rq, p);
+
+	if (hrtick_enabled(rq))
+		start_hrtick_dl(rq, p);
+
+	deadline_queue_push_tasks(rq);
+
+	if (rq->curr->sched_class != &dl_sched_class)
+		update_dl_rq_load_avg(rq_clock_task(rq), rq, 0);
+
+	return p;
+}
+
+static void put_prev_task_dl(struct rq *rq, struct task_struct *p)
+{
+	update_curr_dl(rq);
+
+	update_dl_rq_load_avg(rq_clock_task(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_task(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(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()
+	 */
+}
+
+static void set_curr_task_dl(struct rq *rq)
+{
+	struct task_struct *p = rq->curr;
+
+	p->se.exec_start = rq_clock_task(rq);
+
+	/* You can't push away the running task */
+	dequeue_pushable_dl_task(rq, p);
+}
+
+#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_running(rq, p) &&
+	    cpumask_test_cpu(cpu, &p->cpus_allowed))
+		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 rb_node *next_node = rq->dl.pushable_dl_tasks_root.rb_leftmost;
+	struct task_struct *p = NULL;
+
+	if (!has_pushable_dl_tasks(rq))
+		return NULL;
+
+next_node:
+	if (next_node) {
+		p = rb_entry(next_node, struct task_struct, pushable_dl_tasks);
+
+		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_first_and(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(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 (later_rq->dl.dl_nr_running &&
+		    !dl_time_before(task->dl.deadline,
+					later_rq->dl.earliest_dl.curr)) {
+			/*
+			 * 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_allowed) ||
+				     task_running(rq, task) ||
+				     !dl_task(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 (!later_rq->dl.dl_nr_running ||
+		    dl_time_before(task->dl.deadline,
+				   later_rq->dl.earliest_dl.curr))
+			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 = rb_entry(rq->dl.pushable_dl_tasks_root.rb_leftmost,
+		     struct task_struct, pushable_dl_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(!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 (unlikely(next_task == rq->curr)) {
+		WARN_ON(1);
+		return 0;
+	}
+
+	/*
+	 * 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;
+	}
+
+	/* 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);
+	sub_running_bw(&next_task->dl, &rq->dl);
+	sub_rq_bw(&next_task->dl, &rq->dl);
+	set_task_cpu(next_task, later_rq->cpu);
+	add_rq_bw(&next_task->dl, &later_rq->dl);
+
+	/*
+	 * Update the later_rq clock here, because the clock is used
+	 * by the cpufreq_update_util() inside __add_running_bw().
+	 */
+	update_rq_clock(later_rq);
+	add_running_bw(&next_task->dl, &later_rq->dl);
+	activate_task(later_rq, next_task, ENQUEUE_NOCLOCK);
+	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;
+	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 */
+		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) &&
+		    (!this_rq->dl.dl_nr_running ||
+		     dl_time_before(p->dl.deadline,
+				    this_rq->dl.earliest_dl.curr))) {
+			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;
+
+			resched = true;
+
+			deactivate_task(src_rq, p, 0);
+			sub_running_bw(&p->dl, &src_rq->dl);
+			sub_rq_bw(&p->dl, &src_rq->dl);
+			set_task_cpu(p, this_cpu);
+			add_rq_bw(&p->dl, &this_rq->dl);
+			add_running_bw(&p->dl, &this_rq->dl);
+			activate_task(this_rq, p, 0);
+			dmin = p->dl.deadline;
+
+			/* Is there any other task even earlier? */
+		}
+skip:
+		double_unlock_balance(this_rq, src_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_running(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,
+				const struct cpumask *new_mask)
+{
+	struct root_domain *src_rd;
+	struct rq *rq;
+
+	BUG_ON(!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, 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, new_mask);
+}
+
+/* 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));
+}
+
+#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);
+
+	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);
+
+	/* 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);
+	}
+}
+
+/*
+ * 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) || rq->curr == p) {
+#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 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
+		/*
+		 * Again, 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 /* CONFIG_SMP */
+	}
+}
+
+const struct sched_class dl_sched_class = {
+	.next			= &rt_sched_class,
+	.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,
+
+#ifdef CONFIG_SMP
+	.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,
+#endif
+
+	.set_curr_task		= set_curr_task_dl,
+	.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,
+};
+
+int sched_dl_global_validate(void)
+{
+	u64 runtime = global_rt_runtime();
+	u64 period = global_rt_period();
+	u64 new_bw = to_ratio(period, runtime);
+	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.
+	 *
+	 * FIXME: Cycling on all the CPUs is overdoing, but simpler than
+	 * cycling on root_domains... Discussion on different/better
+	 * solutions is welcome!
+	 */
+	for_each_possible_cpu(cpu) {
+		rcu_read_lock_sched();
+		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);
+
+		rcu_read_unlock_sched();
+
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
+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->extra_bw = 1 << BW_SHIFT;
+	} else {
+		dl_rq->bw_ratio = to_ratio(global_rt_runtime(),
+			  global_rt_period()) >> (BW_SHIFT - RATIO_SHIFT);
+		dl_rq->extra_bw = to_ratio(global_rt_period(),
+						    global_rt_runtime());
+	}
+}
+
+void sched_dl_do_global(void)
+{
+	u64 new_bw = -1;
+	struct dl_bw *dl_b;
+	int cpu;
+	unsigned long flags;
+
+	def_dl_bandwidth.dl_period = global_rt_period();
+	def_dl_bandwidth.dl_runtime = global_rt_runtime();
+
+	if (global_rt_runtime() != RUNTIME_INF)
+		new_bw = to_ratio(global_rt_period(), global_rt_runtime());
+
+	/*
+	 * FIXME: As above...
+	 */
+	for_each_possible_cpu(cpu) {
+		rcu_read_lock_sched();
+		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)
+{
+	struct dl_bw *dl_b = dl_bw_of(task_cpu(p));
+	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;
+
+	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(task_cpu(p));
+	if (dl_policy(policy) && !task_has_dl_policy(p) &&
+	    !__dl_overflow(dl_b, cpus, 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, cpus, 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)
+{
+	/* 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;
+
+	/* runtime <= deadline <= period (if period != 0) */
+	if ((attr->sched_period != 0 &&
+	     attr->sched_period < attr->sched_deadline) ||
+	    attr->sched_deadline < attr->sched_runtime)
+		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_boosted		= 0;
+	dl_se->dl_throttled		= 0;
+	dl_se->dl_yielded		= 0;
+	dl_se->dl_non_contending	= 0;
+	dl_se->dl_overrun		= 0;
+}
+
+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_task_can_attach(struct task_struct *p, const struct cpumask *cs_cpus_allowed)
+{
+	unsigned int dest_cpu;
+	struct dl_bw *dl_b;
+	bool overflow;
+	int cpus, ret;
+	unsigned long flags;
+
+	dest_cpu = cpumask_any_and(cpu_active_mask, cs_cpus_allowed);
+
+	rcu_read_lock_sched();
+	dl_b = dl_bw_of(dest_cpu);
+	raw_spin_lock_irqsave(&dl_b->lock, flags);
+	cpus = dl_bw_cpus(dest_cpu);
+	overflow = __dl_overflow(dl_b, cpus, 0, p->dl.dl_bw);
+	if (overflow) {
+		ret = -EBUSY;
+	} else {
+		/*
+		 * We reserve space for this task 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, p->dl.dl_bw, cpus);
+		ret = 0;
+	}
+	raw_spin_unlock_irqrestore(&dl_b->lock, flags);
+	rcu_read_unlock_sched();
+
+	return ret;
+}
+
+int dl_cpuset_cpumask_can_shrink(const struct cpumask *cur,
+				 const struct cpumask *trial)
+{
+	int ret = 1, trial_cpus;
+	struct dl_bw *cur_dl_b;
+	unsigned long flags;
+
+	rcu_read_lock_sched();
+	cur_dl_b = dl_bw_of(cpumask_any(cur));
+	trial_cpus = cpumask_weight(trial);
+
+	raw_spin_lock_irqsave(&cur_dl_b->lock, flags);
+	if (cur_dl_b->bw != -1 &&
+	    cur_dl_b->bw * trial_cpus < cur_dl_b->total_bw)
+		ret = 0;
+	raw_spin_unlock_irqrestore(&cur_dl_b->lock, flags);
+	rcu_read_unlock_sched();
+
+	return ret;
+}
+
+bool dl_cpu_busy(unsigned int cpu)
+{
+	unsigned long flags;
+	struct dl_bw *dl_b;
+	bool overflow;
+	int cpus;
+
+	rcu_read_lock_sched();
+	dl_b = dl_bw_of(cpu);
+	raw_spin_lock_irqsave(&dl_b->lock, flags);
+	cpus = dl_bw_cpus(cpu);
+	overflow = __dl_overflow(dl_b, cpus, 0, 0);
+	raw_spin_unlock_irqrestore(&dl_b->lock, flags);
+	rcu_read_unlock_sched();
+
+	return overflow;
+}
+#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 */