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Commit a59855cd authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

time: hrtimer: Introduce hrtimer_next_event_without() 



The next set of changes will need to compute the time to the next
hrtimer event over all hrtimers except for the scheduler tick one.

To that end introduce a new helper function,
hrtimer_next_event_without(), for computing the time until the next
hrtimer event over all timers except for one and modify the underlying
code in __hrtimer_next_event_base() to prepare it for being called by
that new function.

No intentional changes in functionality.

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarFrederic Weisbecker <frederic@kernel.org>
parent 23a8d888

include/linux/hrtimer.h

+1 −0
Original line number Diff line number Diff line
@@ -426,6 +426,7 @@ static inline ktime_t hrtimer_get_remaining(const struct hrtimer *timer) 
}



extern u64 hrtimer_get_next_event(void);

extern u64 hrtimer_next_event_without(const struct hrtimer *exclude);



extern bool hrtimer_active(const struct hrtimer *timer);

kernel/time/hrtimer.c

+53 −2
Original line number Diff line number Diff line
@@ -490,6 +490,7 @@ __next_base(struct hrtimer_cpu_base *cpu_base, unsigned int *active) 
	while ((base = __next_base((cpu_base), &(active))))



static ktime_t __hrtimer_next_event_base(struct hrtimer_cpu_base *cpu_base,

					 const struct hrtimer *exclude,

					 unsigned int active,

					 ktime_t expires_next)

{
@@ -502,9 +503,24 @@ static ktime_t __hrtimer_next_event_base(struct hrtimer_cpu_base *cpu_base, 


		next = timerqueue_getnext(&base->active);

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

		if (timer == exclude) {

			/* Get to the next timer in the queue. */

			struct rb_node *rbn = rb_next(&next->node);



			next = rb_entry_safe(rbn, struct timerqueue_node, node);

			if (!next)

				continue;



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

		}

		expires = ktime_sub(hrtimer_get_expires(timer), base->offset);

		if (expires < expires_next) {

			expires_next = expires;



			/* Skip cpu_base update if a timer is being excluded. */

			if (exclude)

				continue;



			if (timer->is_soft)

				cpu_base->softirq_next_timer = timer;

			else
@@ -548,7 +564,8 @@ __hrtimer_get_next_event(struct hrtimer_cpu_base *cpu_base, unsigned int active_ 
	if (!cpu_base->softirq_activated && (active_mask & HRTIMER_ACTIVE_SOFT)) {

		active = cpu_base->active_bases & HRTIMER_ACTIVE_SOFT;

		cpu_base->softirq_next_timer = NULL;

		expires_next = __hrtimer_next_event_base(cpu_base, active, KTIME_MAX);

		expires_next = __hrtimer_next_event_base(cpu_base, NULL,

							 active, KTIME_MAX);



		next_timer = cpu_base->softirq_next_timer;

	}
@@ -556,7 +573,8 @@ __hrtimer_get_next_event(struct hrtimer_cpu_base *cpu_base, unsigned int active_ 
	if (active_mask & HRTIMER_ACTIVE_HARD) {

		active = cpu_base->active_bases & HRTIMER_ACTIVE_HARD;

		cpu_base->next_timer = next_timer;

		expires_next = __hrtimer_next_event_base(cpu_base, active, expires_next);

		expires_next = __hrtimer_next_event_base(cpu_base, NULL, active,

							 expires_next);

	}



	return expires_next;
@@ -1202,6 +1220,39 @@ u64 hrtimer_get_next_event(void) 


	return expires;

}



/**

 * hrtimer_next_event_without - time until next expiry event w/o one timer

 * @exclude:	timer to exclude

 *

 * Returns the next expiry time over all timers except for the @exclude one or

 * KTIME_MAX if none of them is pending.

 */

u64 hrtimer_next_event_without(const struct hrtimer *exclude)

{

	struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);

	u64 expires = KTIME_MAX;

	unsigned long flags;



	raw_spin_lock_irqsave(&cpu_base->lock, flags);



	if (__hrtimer_hres_active(cpu_base)) {

		unsigned int active;



		if (!cpu_base->softirq_activated) {

			active = cpu_base->active_bases & HRTIMER_ACTIVE_SOFT;

			expires = __hrtimer_next_event_base(cpu_base, exclude,

							    active, KTIME_MAX);

		}

		active = cpu_base->active_bases & HRTIMER_ACTIVE_HARD;

		expires = __hrtimer_next_event_base(cpu_base, exclude, active,

						    expires);

	}



	raw_spin_unlock_irqrestore(&cpu_base->lock, flags);



	return expires;

}

#endif



static inline int hrtimer_clockid_to_base(clockid_t clock_id)