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Commit e4bb211a authored by Viresh Kumar's avatar Viresh Kumar Committed by Satya Durga Srinivasu Prabhala
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hrtimer: create hrtimer_quiesce_cpu() to isolate CPU from hrtimers 



To isolate CPUs (isolate from hrtimers) from sysfs using cpusets, we need some
support from the hrtimer core. i.e. A routine hrtimer_quiesce_cpu() which would
migrate away all the unpinned hrtimers, but shouldn't touch the pinned ones.

This patch creates this routine.

Change-Id: Icf93622bdeed9c6c28eb1aca1637bc5b9522a533
Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
[forward port to 3.18]
Signed-off-by: default avatarSantosh Shukla <santosh.shukla@linaro.org>
[ohaugan@codeaurora.org: Port to 4.4]
Git-commit: d4d50a0ddc35e58ee95137ba4d14e74fea8b682f
Git-repo: git://git.linaro.org/people/mike.holmes/santosh.shukla/lng-isol.git


Signed-off-by: default avatarOlav Haugan <ohaugan@codeaurora.org>
[rameezmustafa@codeaurora.org: Port to msm-4.9]
Signed-off-by: default avatarSyed Rameez Mustafa <rameezmustafa@codeaurora.org>
[satyap@codeaurora.org: Port to msm-4.19 and fix merge conflicts]
Signed-off-by: default avatarSatya Durga Srinivasu Prabhala <satyap@codeaurora.org>
parent de27e145

include/linux/hrtimer.h

+3 −0
Original line number Original line Diff line number Diff line
@@ -364,6 +364,9 @@ DECLARE_PER_CPU(struct tick_device, tick_cpu_device); 




/* Exported timer functions: */

/* Exported timer functions: */





/* To be used from cpusets, only */

extern void hrtimer_quiesce_cpu(void *cpup);



/* Initialize timers: */

/* Initialize timers: */

extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,

extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,

			 enum hrtimer_mode mode);

			 enum hrtimer_mode mode);

kernel/time/hrtimer.c

+44 −11
Original line number Original line Diff line number Diff line
@@ -1830,13 +1830,17 @@ int hrtimers_prepare_cpu(unsigned int cpu) 
	return 0;

	return 0;

}

}





#ifdef CONFIG_HOTPLUG_CPU

#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_CPUSETS)



static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,

static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,

				struct hrtimer_clock_base *new_base)

				 struct hrtimer_clock_base *new_base,

				 bool remove_pinned)

{

{

	struct hrtimer *timer;

	struct hrtimer *timer;

	struct timerqueue_node *node;

	struct timerqueue_node *node;

	struct timerqueue_head pinned;

	int is_pinned;



	timerqueue_init_head(&pinned);





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

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

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

		timer = container_of(node, struct hrtimer, node);
@@ -1849,6 +1853,13 @@ static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base, 
		 * under us on another CPU

		 * under us on another CPU

		 */

		 */

		__remove_hrtimer(timer, old_base, HRTIMER_STATE_ENQUEUED, 0);

		__remove_hrtimer(timer, old_base, HRTIMER_STATE_ENQUEUED, 0);



		is_pinned = timer->state & HRTIMER_STATE_PINNED;

		if (!remove_pinned && is_pinned) {

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

			continue;

		}



		timer->base = new_base;

		timer->base = new_base;

		/*

		/*

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

		 * Enqueue the timers on the new cpu. This does not
@@ -1860,23 +1871,29 @@ static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base, 
		 */

		 */

		enqueue_hrtimer(timer, new_base, HRTIMER_MODE_ABS);

		enqueue_hrtimer(timer, new_base, HRTIMER_MODE_ABS);

	}

	}



	/* Re-queue pinned timers for non-hotplug usecase */

	while ((node = timerqueue_getnext(&pinned))) {

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



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

		enqueue_hrtimer(timer, old_base, HRTIMER_MODE_ABS);

	}

}

}





int hrtimers_dead_cpu(unsigned int scpu)

static void __migrate_hrtimers(unsigned int scpu, bool remove_pinned)

{

{

	struct hrtimer_cpu_base *old_base, *new_base;

	struct hrtimer_cpu_base *old_base, *new_base;

	unsigned long flags;

	int i;

	int i;





	BUG_ON(cpu_online(scpu));

	tick_cancel_sched_timer(scpu);



	/*

	/*

	 * this BH disable ensures that raise_softirq_irqoff() does

	 * this BH disable ensures that raise_softirq_irqoff() does

	 * not wakeup ksoftirqd (and acquire the pi-lock) while

	 * not wakeup ksoftirqd (and acquire the pi-lock) while

	 * holding the cpu_base lock

	 * holding the cpu_base lock

	 */

	 */

	local_bh_disable();

	local_bh_disable();

	local_irq_disable();

	local_irq_save(flags);

	old_base = &per_cpu(hrtimer_bases, scpu);

	old_base = &per_cpu(hrtimer_bases, scpu);

	new_base = this_cpu_ptr(&hrtimer_bases);

	new_base = this_cpu_ptr(&hrtimer_bases);

	/*

	/*
@@ -1888,7 +1905,7 @@ int hrtimers_dead_cpu(unsigned int scpu) 




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

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

		migrate_hrtimer_list(&old_base->clock_base[i],

		migrate_hrtimer_list(&old_base->clock_base[i],

				     &new_base->clock_base[i]);

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

	}

	}





	/*

	/*
@@ -1902,13 +1919,29 @@ int hrtimers_dead_cpu(unsigned int scpu) 




	/* Check, if we got expired work to do */

	/* Check, if we got expired work to do */

	__hrtimer_peek_ahead_timers();

	__hrtimer_peek_ahead_timers();

	local_irq_enable();

	local_irq_restore(flags);

	local_bh_enable();

	local_bh_enable();

	return 0;

}

}

#endif /* CONFIG_HOTPLUG_CPU || CONFIG_CPUSETS */



#ifdef CONFIG_HOTPLUG_CPU

int hrtimers_dead_cpu(unsigned int scpu)

{

	BUG_ON(cpu_online(scpu));

	tick_cancel_sched_timer(scpu);





	__migrate_hrtimers(scpu, true);

	return 0;

}

#endif /* CONFIG_HOTPLUG_CPU */

#endif /* CONFIG_HOTPLUG_CPU */





#ifdef CONFIG_CPUSETS

void hrtimer_quiesce_cpu(void *cpup)

{

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

}

#endif /* CONFIG_CPUSETS */



void __init hrtimers_init(void)

void __init hrtimers_init(void)

{

{

	hrtimers_prepare_cpu(smp_processor_id());

	hrtimers_prepare_cpu(smp_processor_id());