Merge "timer: create timer_quiesce_cpu() to isolate CPU from timers" (8dfdffca) · Commits · e / devices / android_kernel_fairphone_FP5

include/linux/timer.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -182,6 +182,9 @@ extern bool check_pending_deferrable_timers(int cpu);
		*/
		#define NEXT_TIMER_MAX_DELTA ((1UL << 30) - 1)

		/* To be used from cpusets, only */
		extern void timer_quiesce_cpu(void *cpup);

		extern void add_timer(struct timer_list *timer);

		extern int try_to_del_timer_sync(struct timer_list *timer);

kernel/time/timer.c

+22 −10

Original line number	Diff line number	Diff line
		@@ -1981,14 +1981,20 @@ signed long __sched schedule_timeout_idle(signed long timeout)
		EXPORT_SYMBOL(schedule_timeout_idle);

		#ifdef CONFIG_HOTPLUG_CPU
		static void migrate_timer_list(struct timer_base new_base, struct hlist_head head)
		static void migrate_timer_list(struct timer_base *new_base,
		struct hlist_head *head, bool remove_pinned)
		{
		struct timer_list *timer;
		int cpu = new_base->cpu;
		struct hlist_node *n;
		int is_pinned;

		while (!hlist_empty(head)) {
		timer = hlist_entry(head->first, struct timer_list, entry);
		detach_timer(timer, false);
		hlist_for_each_entry_safe(timer, n, head, entry) {
		is_pinned = timer->flags & TIMER_PINNED;
		if (!remove_pinned && is_pinned)
		continue;

		detach_if_pending(timer, get_timer_base(timer->flags), false);
		timer->flags = (timer->flags & ~TIMER_BASEMASK) \| cpu;
		internal_add_timer(new_base, timer);
		}
		@@ -2009,14 +2015,13 @@ int timers_prepare_cpu(unsigned int cpu)
		return 0;
		}

		int timers_dead_cpu(unsigned int cpu)
		static void __migrate_timers(unsigned int cpu, bool remove_pinned)
		{
		struct timer_base *old_base;
		struct timer_base *new_base;
		unsigned long flags;
		int b, i;

		BUG_ON(cpu_online(cpu));

		for (b = 0; b < NR_BASES; b++) {
		old_base = per_cpu_ptr(&timer_bases[b], cpu);
		new_base = get_cpu_ptr(&timer_bases[b]);
		@@ -2024,7 +2029,7 @@ int timers_dead_cpu(unsigned int cpu)
		* The caller is globally serialized and nobody else
		* takes two locks at once, deadlock is not possible.
		*/
		raw_spin_lock_irq(&new_base->lock);
		raw_spin_lock_irqsave(&new_base->lock, flags);
		raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);

		/*
		@@ -2036,12 +2041,19 @@ int timers_dead_cpu(unsigned int cpu)
		BUG_ON(old_base->running_timer);

		for (i = 0; i < WHEEL_SIZE; i++)
		migrate_timer_list(new_base, old_base->vectors + i);
		migrate_timer_list(new_base, old_base->vectors + i,
		remove_pinned);

		raw_spin_unlock(&old_base->lock);
		raw_spin_unlock_irq(&new_base->lock);
		raw_spin_unlock_irqrestore(&new_base->lock, flags);
		put_cpu_ptr(&timer_bases);
		}
		}

		int timers_dead_cpu(unsigned int cpu)
		{
		BUG_ON(cpu_online(cpu));
		__migrate_timers(cpu, true);
		return 0;
		}