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Commit 62abf225 authored by Olav Haugan's avatar Olav Haugan
Browse files

hrtimer: Ensure timer is not running before migrating 



A timer might be running when we are trying to move the timer to another
CPU so ensure that we wait for the timer to finish before migrating.

Change-Id: I4c9ee39c715baebfbdb8a50476a475e38b092f70
Signed-off-by: default avatarOlav Haugan <ohaugan@codeaurora.org>
parent 46692be6

kernel/time/hrtimer.c

+29 −13
Original line number Diff line number Diff line
@@ -1625,20 +1625,36 @@ static void init_hrtimers_cpu(int cpu) 
}



#if defined(CONFIG_HOTPLUG_CPU)

static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,

				 struct hrtimer_clock_base *new_base,

static void migrate_hrtimer_list(struct hrtimer_cpu_base *old_base,

				 struct hrtimer_cpu_base *new_base,

				 unsigned int i,

				 bool wait,

				 bool remove_pinned)

{

	struct hrtimer *timer;

	struct timerqueue_node *node;

	struct timerqueue_head pinned;

	int is_pinned;

	struct hrtimer_clock_base *old_c_base = &old_base->clock_base[i];

	struct hrtimer_clock_base *new_c_base = &new_base->clock_base[i];



	timerqueue_init_head(&pinned);



	while ((node = timerqueue_getnext(&old_base->active))) {

	while ((node = timerqueue_getnext(&old_c_base->active))) {

		timer = container_of(node, struct hrtimer, node);

		if (wait) {

			/* Ensure timers are done running before continuing */

			while (hrtimer_callback_running(timer)) {

				raw_spin_unlock(&old_base->lock);

				raw_spin_unlock(&new_base->lock);

				cpu_relax();

				raw_spin_lock(&new_base->lock);

				raw_spin_lock_nested(&old_base->lock,

							SINGLE_DEPTH_NESTING);

			}

		} else {

			BUG_ON(hrtimer_callback_running(timer));

		}

		debug_deactivate(timer);



		/*
@@ -1646,7 +1662,7 @@ static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base, 
		 * timer could be seen as !active and just vanish away

		 * under us on another CPU

		 */

		__remove_hrtimer(timer, old_base, HRTIMER_STATE_ENQUEUED, 0);

		__remove_hrtimer(timer, old_c_base, HRTIMER_STATE_ENQUEUED, 0);



		is_pinned = timer->state & HRTIMER_STATE_PINNED;

		if (!remove_pinned && is_pinned) {
@@ -1654,7 +1670,7 @@ static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base, 
			continue;

		}



		timer->base = new_base;

		timer->base = new_c_base;

		/*

		 * Enqueue the timers on the new cpu. This does not

		 * reprogram the event device in case the timer
@@ -1663,7 +1679,7 @@ static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base, 
		 * sort out already expired timers and reprogram the

		 * event device.

		 */

		enqueue_hrtimer(timer, new_base);

		enqueue_hrtimer(timer, new_c_base);

	}



	/* Re-queue pinned timers for non-hotplug usecase */
@@ -1671,11 +1687,11 @@ static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base, 
		timer = container_of(node, struct hrtimer, node);



		timerqueue_del(&pinned, &timer->node);

		enqueue_hrtimer(timer, old_base);

		enqueue_hrtimer(timer, old_c_base);

	}

}



static void __migrate_hrtimers(int scpu, bool remove_pinned)

static void __migrate_hrtimers(int scpu, bool wait, bool remove_pinned)

{

	struct hrtimer_cpu_base *old_base, *new_base;

	unsigned long flags;
@@ -1692,8 +1708,8 @@ static void __migrate_hrtimers(int scpu, bool remove_pinned) 
	raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);



	for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {

		migrate_hrtimer_list(&old_base->clock_base[i],

				     &new_base->clock_base[i], remove_pinned);

		migrate_hrtimer_list(old_base, new_base, i, wait,

								remove_pinned);

	}



	raw_spin_unlock(&old_base->lock);
@@ -1709,12 +1725,12 @@ static void migrate_hrtimers(int scpu) 
	BUG_ON(cpu_online(scpu));

	tick_cancel_sched_timer(scpu);



	__migrate_hrtimers(scpu, true);

	__migrate_hrtimers(scpu, false, true);

}



void hrtimer_quiesce_cpu(void *cpup)

{

	__migrate_hrtimers(*(int *)cpup, false);

	__migrate_hrtimers(*(int *)cpup, true, false);

}



#endif /* CONFIG_HOTPLUG_CPU */