Merging debian version 4.19.260-1.

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

1 files changed, 0 insertions, 616 deletions

diff --git a/debian/patches-rt/0308-sched-Lazy-migrate_disable-processing.patch b/debian/patches-rt/0308-sched-Lazy-migrate_disable-processing.patch
deleted file mode 100644
index 973b6e870..000000000
--- a/debian/patches-rt/0308-sched-Lazy-migrate_disable-processing.patch
+++ /dev/null
@@ -1,616 +0,0 @@
-From 34b182c6f6606c5a02a3ddea15356251ca28093b Mon Sep 17 00:00:00 2001
-From: Scott Wood <swood@redhat.com>
-Date: Sat, 12 Oct 2019 01:52:13 -0500
-Subject: [PATCH 308/347] sched: Lazy migrate_disable processing
-Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz
-
-[ Upstream commit 425c5b38779a860062aa62219dc920d374b13c17 ]
-
-Avoid overhead on the majority of migrate disable/enable sequences by
-only manipulating scheduler data (and grabbing the relevant locks) when
-the task actually schedules while migrate-disabled.  A kernel build
-showed around a 10% reduction in system time (with CONFIG_NR_CPUS=512).
-
-Instead of cpuhp_pin_lock, CPU hotplug is handled by keeping a per-CPU
-count of the number of pinned tasks (including tasks which have not
-scheduled in the migrate-disabled section); takedown_cpu() will
-wait until that reaches zero (confirmed by take_cpu_down() in stop
-machine context to deal with races) before migrating tasks off of the
-cpu.
-
-To simplify synchronization, updating cpus_mask is no longer deferred
-until migrate_enable().  This lets us not have to worry about
-migrate_enable() missing the update if it's on the fast path (didn't
-schedule during the migrate disabled section).  It also makes the code
-a bit simpler and reduces deviation from mainline.
-
-While the main motivation for this is the performance benefit, lazy
-migrate disable also eliminates the restriction on calling
-migrate_disable() while atomic but leaving the atomic region prior to
-calling migrate_enable() -- though this won't help with local_bh_disable()
-(and thus rcutorture) unless something similar is done with the recently
-added local_lock.
-
-Signed-off-by: Scott Wood <swood@redhat.com>
-Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
-Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
----
- include/linux/cpu.h    |   4 -
- include/linux/sched.h  |  11 +--
- init/init_task.c       |   4 +
- kernel/cpu.c           | 103 +++++++++--------------
- kernel/sched/core.c    | 182 +++++++++++++++++------------------------
- kernel/sched/sched.h   |   4 +
- lib/smp_processor_id.c |   3 +
- 7 files changed, 129 insertions(+), 182 deletions(-)
-
-diff --git a/include/linux/cpu.h b/include/linux/cpu.h
-index e67645924404..87347ccbba0c 100644
---- a/include/linux/cpu.h
-+++ b/include/linux/cpu.h
-@@ -118,8 +118,6 @@ extern void cpu_hotplug_disable(void);
- extern void cpu_hotplug_enable(void);
- void clear_tasks_mm_cpumask(int cpu);
- int cpu_down(unsigned int cpu);
--extern void pin_current_cpu(void);
--extern void unpin_current_cpu(void);
- 
- #else /* CONFIG_HOTPLUG_CPU */
- 
-@@ -131,8 +129,6 @@ static inline int  cpus_read_trylock(void) { return true; }
- static inline void lockdep_assert_cpus_held(void) { }
- static inline void cpu_hotplug_disable(void) { }
- static inline void cpu_hotplug_enable(void) { }
--static inline void pin_current_cpu(void) { }
--static inline void unpin_current_cpu(void) { }
- 
- #endif	/* !CONFIG_HOTPLUG_CPU */
- 
-diff --git a/include/linux/sched.h b/include/linux/sched.h
-index e567fe2d7058..65069db8923c 100644
---- a/include/linux/sched.h
-+++ b/include/linux/sched.h
-@@ -227,6 +227,8 @@ extern void io_schedule_finish(int token);
- extern long io_schedule_timeout(long timeout);
- extern void io_schedule(void);
- 
-+int cpu_nr_pinned(int cpu);
-+
- /**
-  * struct prev_cputime - snapshot of system and user cputime
-  * @utime: time spent in user mode
-@@ -670,16 +672,13 @@ struct task_struct {
- 	cpumask_t			cpus_mask;
- #if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT_BASE)
- 	int				migrate_disable;
--	int				migrate_disable_update;
--	int				pinned_on_cpu;
-+	bool				migrate_disable_scheduled;
- # ifdef CONFIG_SCHED_DEBUG
--	int				migrate_disable_atomic;
-+	int				pinned_on_cpu;
- # endif
--
- #elif !defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT_BASE)
- # ifdef CONFIG_SCHED_DEBUG
- 	int				migrate_disable;
--	int				migrate_disable_atomic;
- # endif
- #endif
- #ifdef CONFIG_PREEMPT_RT_FULL
-@@ -2058,4 +2057,6 @@ static inline void rseq_syscall(struct pt_regs *regs)
- 
- #endif
- 
-+extern struct task_struct *takedown_cpu_task;
-+
- #endif
-diff --git a/init/init_task.c b/init/init_task.c
-index 634becebd713..45b84137c4b3 100644
---- a/init/init_task.c
-+++ b/init/init_task.c
-@@ -80,6 +80,10 @@ struct task_struct init_task
- 	.cpus_ptr	= &init_task.cpus_mask,
- 	.cpus_mask	= CPU_MASK_ALL,
- 	.nr_cpus_allowed= NR_CPUS,
-+#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT_BASE) && \
-+    defined(CONFIG_SCHED_DEBUG)
-+	.pinned_on_cpu	= -1,
-+#endif
- 	.mm		= NULL,
- 	.active_mm	= &init_mm,
- 	.restart_block	= {
-diff --git a/kernel/cpu.c b/kernel/cpu.c
-index c84a93f84164..edd4fd8da726 100644
---- a/kernel/cpu.c
-+++ b/kernel/cpu.c
-@@ -77,11 +77,6 @@ static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state) = {
- 	.fail = CPUHP_INVALID,
- };
- 
--#if defined(CONFIG_HOTPLUG_CPU) && defined(CONFIG_PREEMPT_RT_FULL)
--static DEFINE_PER_CPU(struct rt_rw_lock, cpuhp_pin_lock) = \
--	__RWLOCK_RT_INITIALIZER(cpuhp_pin_lock);
--#endif
--
- #if defined(CONFIG_LOCKDEP) && defined(CONFIG_SMP)
- static struct lockdep_map cpuhp_state_up_map =
- 	STATIC_LOCKDEP_MAP_INIT("cpuhp_state-up", &cpuhp_state_up_map);
-@@ -288,57 +283,6 @@ static int cpu_hotplug_disabled;
- 
- #ifdef CONFIG_HOTPLUG_CPU
- 
--/**
-- * pin_current_cpu - Prevent the current cpu from being unplugged
-- */
--void pin_current_cpu(void)
--{
--#ifdef CONFIG_PREEMPT_RT_FULL
--	struct rt_rw_lock *cpuhp_pin;
--	unsigned int cpu;
--	int ret;
--
--again:
--	cpuhp_pin = this_cpu_ptr(&cpuhp_pin_lock);
--	ret = __read_rt_trylock(cpuhp_pin);
--	if (ret) {
--		current->pinned_on_cpu = smp_processor_id();
--		return;
--	}
--	cpu = smp_processor_id();
--	preempt_lazy_enable();
--	preempt_enable();
--
--	sleeping_lock_inc();
--	__read_rt_lock(cpuhp_pin);
--	sleeping_lock_dec();
--
--	preempt_disable();
--	preempt_lazy_disable();
--	if (cpu != smp_processor_id()) {
--		__read_rt_unlock(cpuhp_pin);
--		goto again;
--	}
--	current->pinned_on_cpu = cpu;
--#endif
--}
--
--/**
-- * unpin_current_cpu - Allow unplug of current cpu
-- */
--void unpin_current_cpu(void)
--{
--#ifdef CONFIG_PREEMPT_RT_FULL
--	struct rt_rw_lock *cpuhp_pin = this_cpu_ptr(&cpuhp_pin_lock);
--
--	if (WARN_ON(current->pinned_on_cpu != smp_processor_id()))
--		cpuhp_pin = per_cpu_ptr(&cpuhp_pin_lock, current->pinned_on_cpu);
--
--	current->pinned_on_cpu = -1;
--	__read_rt_unlock(cpuhp_pin);
--#endif
--}
--
- DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock);
- 
- void cpus_read_lock(void)
-@@ -932,6 +876,15 @@ static int take_cpu_down(void *_param)
- 	int err, cpu = smp_processor_id();
- 	int ret;
- 
-+#ifdef CONFIG_PREEMPT_RT_BASE
-+	/*
-+	 * If any tasks disabled migration before we got here,
-+	 * go back and sleep again.
-+	 */
-+	if (cpu_nr_pinned(cpu))
-+		return -EAGAIN;
-+#endif
-+
- 	/* Ensure this CPU doesn't handle any more interrupts. */
- 	err = __cpu_disable();
- 	if (err < 0)
-@@ -959,11 +912,10 @@ static int take_cpu_down(void *_param)
- 	return 0;
- }
- 
-+struct task_struct *takedown_cpu_task;
-+
- static int takedown_cpu(unsigned int cpu)
- {
--#ifdef CONFIG_PREEMPT_RT_FULL
--	struct rt_rw_lock *cpuhp_pin = per_cpu_ptr(&cpuhp_pin_lock, cpu);
--#endif
- 	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
- 	int err;
- 
-@@ -976,17 +928,38 @@ static int takedown_cpu(unsigned int cpu)
- 	 */
- 	irq_lock_sparse();
- 
--#ifdef CONFIG_PREEMPT_RT_FULL
--	__write_rt_lock(cpuhp_pin);
-+#ifdef CONFIG_PREEMPT_RT_BASE
-+	WARN_ON_ONCE(takedown_cpu_task);
-+	takedown_cpu_task = current;
-+
-+again:
-+	/*
-+	 * If a task pins this CPU after we pass this check, take_cpu_down
-+	 * will return -EAGAIN.
-+	 */
-+	for (;;) {
-+		int nr_pinned;
-+
-+		set_current_state(TASK_UNINTERRUPTIBLE);
-+		nr_pinned = cpu_nr_pinned(cpu);
-+		if (nr_pinned == 0)
-+			break;
-+		schedule();
-+	}
-+	set_current_state(TASK_RUNNING);
- #endif
- 
- 	/*
- 	 * So now all preempt/rcu users must observe !cpu_active().
- 	 */
- 	err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu));
-+#ifdef CONFIG_PREEMPT_RT_BASE
-+	if (err == -EAGAIN)
-+		goto again;
-+#endif
- 	if (err) {
--#ifdef CONFIG_PREEMPT_RT_FULL
--		__write_rt_unlock(cpuhp_pin);
-+#ifdef CONFIG_PREEMPT_RT_BASE
-+		takedown_cpu_task = NULL;
- #endif
- 		/* CPU refused to die */
- 		irq_unlock_sparse();
-@@ -1006,8 +979,8 @@ static int takedown_cpu(unsigned int cpu)
- 	wait_for_ap_thread(st, false);
- 	BUG_ON(st->state != CPUHP_AP_IDLE_DEAD);
- 
--#ifdef CONFIG_PREEMPT_RT_FULL
--	__write_rt_unlock(cpuhp_pin);
-+#ifdef CONFIG_PREEMPT_RT_BASE
-+	takedown_cpu_task = NULL;
- #endif
- 	/* Interrupts are moved away from the dying cpu, reenable alloc/free */
- 	irq_unlock_sparse();
-diff --git a/kernel/sched/core.c b/kernel/sched/core.c
-index 7eb3037c0b35..de6514e13e0c 100644
---- a/kernel/sched/core.c
-+++ b/kernel/sched/core.c
-@@ -1065,7 +1065,8 @@ static int migration_cpu_stop(void *data)
- void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask)
- {
- 	cpumask_copy(&p->cpus_mask, new_mask);
--	p->nr_cpus_allowed = cpumask_weight(new_mask);
-+	if (p->cpus_ptr == &p->cpus_mask)
-+		p->nr_cpus_allowed = cpumask_weight(new_mask);
- }
- 
- #if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT_BASE)
-@@ -1076,8 +1077,7 @@ int __migrate_disabled(struct task_struct *p)
- EXPORT_SYMBOL_GPL(__migrate_disabled);
- #endif
- 
--static void __do_set_cpus_allowed_tail(struct task_struct *p,
--				       const struct cpumask *new_mask)
-+void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
- {
- 	struct rq *rq = task_rq(p);
- 	bool queued, running;
-@@ -1106,20 +1106,6 @@ static void __do_set_cpus_allowed_tail(struct task_struct *p,
- 		set_curr_task(rq, p);
- }
- 
--void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
--{
--#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT_BASE)
--	if (__migrate_disabled(p)) {
--		lockdep_assert_held(&p->pi_lock);
--
--		cpumask_copy(&p->cpus_mask, new_mask);
--		p->migrate_disable_update = 1;
--		return;
--	}
--#endif
--	__do_set_cpus_allowed_tail(p, new_mask);
--}
--
- /*
-  * 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
-@@ -1179,7 +1165,8 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
- 	}
- 
- 	/* Can the task run on the task's current CPU? If so, we're done */
--	if (cpumask_test_cpu(task_cpu(p), new_mask) || __migrate_disabled(p))
-+	if (cpumask_test_cpu(task_cpu(p), new_mask) ||
-+	    p->cpus_ptr != &p->cpus_mask)
- 		goto out;
- 
- 	if (task_running(rq, p) || p->state == TASK_WAKING) {
-@@ -3459,6 +3446,8 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
- 	BUG();
- }
- 
-+static void migrate_disabled_sched(struct task_struct *p);
-+
- /*
-  * __schedule() is the main scheduler function.
-  *
-@@ -3529,6 +3518,9 @@ static void __sched notrace __schedule(bool preempt)
- 	rq_lock(rq, &rf);
- 	smp_mb__after_spinlock();
- 
-+	if (__migrate_disabled(prev))
-+		migrate_disabled_sched(prev);
-+
- 	/* Promote REQ to ACT */
- 	rq->clock_update_flags <<= 1;
- 	update_rq_clock(rq);
-@@ -5777,6 +5769,8 @@ static void migrate_tasks(struct rq *dead_rq, struct rq_flags *rf)
- 		BUG_ON(!next);
- 		put_prev_task(rq, next);
- 
-+		WARN_ON_ONCE(__migrate_disabled(next));
-+
- 		/*
- 		 * Rules for changing task_struct::cpus_mask are holding
- 		 * both pi_lock and rq->lock, such that holding either
-@@ -7241,14 +7235,9 @@ update_nr_migratory(struct task_struct *p, long delta)
- static inline void
- migrate_disable_update_cpus_allowed(struct task_struct *p)
- {
--	struct rq *rq;
--	struct rq_flags rf;
--
--	rq = task_rq_lock(p, &rf);
- 	p->cpus_ptr = cpumask_of(smp_processor_id());
- 	update_nr_migratory(p, -1);
- 	p->nr_cpus_allowed = 1;
--	task_rq_unlock(rq, p, &rf);
- }
- 
- static inline void
-@@ -7266,54 +7255,35 @@ migrate_enable_update_cpus_allowed(struct task_struct *p)
- 
- void migrate_disable(void)
- {
--	struct task_struct *p = current;
-+	preempt_disable();
- 
--	if (in_atomic() || irqs_disabled()) {
-+	if (++current->migrate_disable == 1) {
-+		this_rq()->nr_pinned++;
-+		preempt_lazy_disable();
- #ifdef CONFIG_SCHED_DEBUG
--		p->migrate_disable_atomic++;
-+		WARN_ON_ONCE(current->pinned_on_cpu >= 0);
-+		current->pinned_on_cpu = smp_processor_id();
- #endif
--		return;
--	}
--#ifdef CONFIG_SCHED_DEBUG
--	if (unlikely(p->migrate_disable_atomic)) {
--		tracing_off();
--		WARN_ON_ONCE(1);
- 	}
--#endif
- 
--	if (p->migrate_disable) {
--		p->migrate_disable++;
--		return;
--	}
-+	preempt_enable();
-+}
-+EXPORT_SYMBOL(migrate_disable);
- 
--	preempt_disable();
--	preempt_lazy_disable();
--	pin_current_cpu();
-+static void migrate_disabled_sched(struct task_struct *p)
-+{
-+	if (p->migrate_disable_scheduled)
-+		return;
- 
- 	migrate_disable_update_cpus_allowed(p);
--	p->migrate_disable = 1;
--
--	preempt_enable();
-+	p->migrate_disable_scheduled = 1;
- }
--EXPORT_SYMBOL(migrate_disable);
- 
- void migrate_enable(void)
- {
- 	struct task_struct *p = current;
--
--	if (in_atomic() || irqs_disabled()) {
--#ifdef CONFIG_SCHED_DEBUG
--		p->migrate_disable_atomic--;
--#endif
--		return;
--	}
--
--#ifdef CONFIG_SCHED_DEBUG
--	if (unlikely(p->migrate_disable_atomic)) {
--		tracing_off();
--		WARN_ON_ONCE(1);
--	}
--#endif
-+	struct rq *rq = this_rq();
-+	int cpu = task_cpu(p);
- 
- 	WARN_ON_ONCE(p->migrate_disable <= 0);
- 	if (p->migrate_disable > 1) {
-@@ -7323,67 +7293,69 @@ void migrate_enable(void)
- 
- 	preempt_disable();
- 
-+#ifdef CONFIG_SCHED_DEBUG
-+	WARN_ON_ONCE(current->pinned_on_cpu != cpu);
-+	current->pinned_on_cpu = -1;
-+#endif
-+
-+	WARN_ON_ONCE(rq->nr_pinned < 1);
-+
- 	p->migrate_disable = 0;
-+	rq->nr_pinned--;
-+	if (rq->nr_pinned == 0 && unlikely(!cpu_active(cpu)) &&
-+	    takedown_cpu_task)
-+		wake_up_process(takedown_cpu_task);
-+
-+	if (!p->migrate_disable_scheduled)
-+		goto out;
-+
-+	p->migrate_disable_scheduled = 0;
-+
- 	migrate_enable_update_cpus_allowed(p);
- 
--	if (p->migrate_disable_update) {
--		struct rq *rq;
-+	WARN_ON(smp_processor_id() != cpu);
-+	if (!is_cpu_allowed(p, cpu)) {
-+		struct migration_arg arg = { p };
- 		struct rq_flags rf;
--		int cpu = task_cpu(p);
- 
- 		rq = task_rq_lock(p, &rf);
- 		update_rq_clock(rq);
--
--		__do_set_cpus_allowed_tail(p, &p->cpus_mask);
-+		arg.dest_cpu = select_fallback_rq(cpu, p);
- 		task_rq_unlock(rq, p, &rf);
- 
--		p->migrate_disable_update = 0;
--
--		WARN_ON(smp_processor_id() != cpu);
--		if (!cpumask_test_cpu(cpu, &p->cpus_mask)) {
--			struct migration_arg arg = { p };
--			struct rq_flags rf;
-+		preempt_lazy_enable();
-+		preempt_enable();
- 
--			rq = task_rq_lock(p, &rf);
--			update_rq_clock(rq);
--			arg.dest_cpu = select_fallback_rq(cpu, p);
--			task_rq_unlock(rq, p, &rf);
--
--			unpin_current_cpu();
--			preempt_lazy_enable();
--			preempt_enable();
--
--			sleeping_lock_inc();
--			stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg);
--			sleeping_lock_dec();
--			tlb_migrate_finish(p->mm);
-+		sleeping_lock_inc();
-+		stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg);
-+		sleeping_lock_dec();
-+		tlb_migrate_finish(p->mm);
- 
--			return;
--		}
-+		return;
- 	}
--	unpin_current_cpu();
-+
-+out:
- 	preempt_lazy_enable();
- 	preempt_enable();
- }
- EXPORT_SYMBOL(migrate_enable);
- 
--#elif !defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT_BASE)
--void migrate_disable(void)
-+int cpu_nr_pinned(int cpu)
- {
--#ifdef CONFIG_SCHED_DEBUG
--	struct task_struct *p = current;
-+	struct rq *rq = cpu_rq(cpu);
- 
--	if (in_atomic() || irqs_disabled()) {
--		p->migrate_disable_atomic++;
--		return;
--	}
-+	return rq->nr_pinned;
-+}
- 
--	if (unlikely(p->migrate_disable_atomic)) {
--		tracing_off();
--		WARN_ON_ONCE(1);
--	}
-+#elif !defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT_BASE)
-+static void migrate_disabled_sched(struct task_struct *p)
-+{
-+}
- 
--	p->migrate_disable++;
-+void migrate_disable(void)
-+{
-+#ifdef CONFIG_SCHED_DEBUG
-+	current->migrate_disable++;
- #endif
- 	barrier();
- }
-@@ -7394,20 +7366,14 @@ void migrate_enable(void)
- #ifdef CONFIG_SCHED_DEBUG
- 	struct task_struct *p = current;
- 
--	if (in_atomic() || irqs_disabled()) {
--		p->migrate_disable_atomic--;
--		return;
--	}
--
--	if (unlikely(p->migrate_disable_atomic)) {
--		tracing_off();
--		WARN_ON_ONCE(1);
--	}
--
- 	WARN_ON_ONCE(p->migrate_disable <= 0);
- 	p->migrate_disable--;
- #endif
- 	barrier();
- }
- EXPORT_SYMBOL(migrate_enable);
-+#else
-+static void migrate_disabled_sched(struct task_struct *p)
-+{
-+}
- #endif
-diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
-index 87a05bb90124..45b3f135d205 100644
---- a/kernel/sched/sched.h
-+++ b/kernel/sched/sched.h
-@@ -915,6 +915,10 @@ struct rq {
- 	/* Must be inspected within a rcu lock section */
- 	struct cpuidle_state	*idle_state;
- #endif
-+
-+#if defined(CONFIG_PREEMPT_RT_BASE) && defined(CONFIG_SMP)
-+	int			nr_pinned;
-+#endif
- };
- 
- static inline int cpu_of(struct rq *rq)
-diff --git a/lib/smp_processor_id.c b/lib/smp_processor_id.c
-index b8a8a8db2d75..0c80992aa337 100644
---- a/lib/smp_processor_id.c
-+++ b/lib/smp_processor_id.c
-@@ -22,6 +22,9 @@ notrace static unsigned int check_preemption_disabled(const char *what1,
- 	 * Kernel threads bound to a single CPU can safely use
- 	 * smp_processor_id():
- 	 */
-+	if (current->migrate_disable)
-+		goto out;
-+
- 	if (current->nr_cpus_allowed == 1)
- 		goto out;
- 
--- 
-2.36.1
-