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Commit 6277dd58 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Todd Kjos
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BACKPORT: 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 code behavior changes.

Cherry-picked from a59855cd8c613ba4bb95147f6176360d95f75e60

 - Fixed conflict with tick_nohz_stopped_cpu not appearing in the
   chunk context. Trivial fix.

Change-Id: I0dae9e08e19559efae9697800738c5522ab5933f
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>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Todd Kjos <tkjos@google.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Paven Kondati <pkondeti@qti.qualcomm.com>
Signed-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
parent f69cfc8e

include/linux/hrtimer.h

+1 −0
Original line number Diff line number Diff line
@@ -405,6 +405,7 @@ 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

+43 −4
Original line number Diff line number Diff line
@@ -463,7 +463,8 @@ static inline void hrtimer_update_next_timer(struct hrtimer_cpu_base *cpu_base, 
#endif

}



static ktime_t __hrtimer_get_next_event(struct hrtimer_cpu_base *cpu_base)

static ktime_t __hrtimer_get_next_event(struct hrtimer_cpu_base *cpu_base,

					const struct hrtimer *exclude)

{

	struct hrtimer_clock_base *base = cpu_base->clock_base;

	unsigned int active = cpu_base->active_bases;
@@ -479,9 +480,24 @@ static ktime_t __hrtimer_get_next_event(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;



			hrtimer_update_next_timer(cpu_base, timer);

		}

	}
@@ -560,7 +576,7 @@ hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal) 
	if (!cpu_base->hres_active)

		return;



	expires_next = __hrtimer_get_next_event(cpu_base);

	expires_next = __hrtimer_get_next_event(cpu_base, NULL);



	if (skip_equal && expires_next == cpu_base->expires_next)

		return;
@@ -1076,7 +1092,30 @@ u64 hrtimer_get_next_event(void) 
	raw_spin_lock_irqsave(&cpu_base->lock, flags);



	if (!__hrtimer_hres_active(cpu_base))

		expires = __hrtimer_get_next_event(cpu_base);

		expires = __hrtimer_get_next_event(cpu_base, NULL);



	raw_spin_unlock_irqrestore(&cpu_base->lock, flags);



	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))

		expires = __hrtimer_get_next_event(cpu_base, exclude);



	raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
@@ -1318,7 +1357,7 @@ void hrtimer_interrupt(struct clock_event_device *dev) 
	__hrtimer_run_queues(cpu_base, now);



	/* Reevaluate the clock bases for the next expiry */

	expires_next = __hrtimer_get_next_event(cpu_base);

	expires_next = __hrtimer_get_next_event(cpu_base, NULL);

	/*

	 * Store the new expiry value so the migration code can verify

	 * against it.