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Commit 022b6fdc authored by Pavankumar Kondeti's avatar Pavankumar Kondeti
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timer: don't wakeup idle CPUs unnecessarily 



Kick the target CPU to re-evaluate the timer wheel only if the
timer being enqueued expires before the programmed next tick
event.

Change-Id: Id467ad069db59885b680f6a8e9f65f1a172af541
Signed-off-by: default avatarPavankumar Kondeti <pkondeti@codeaurora.org>
parent e4b8535d

kernel/time/timer.c

+6 −2
Original line number Diff line number Diff line
@@ -408,6 +408,8 @@ __internal_add_timer(struct tvec_base *base, struct timer_list *timer) 


static void internal_add_timer(struct tvec_base *base, struct timer_list *timer)

{

	int leftmost = 0;



	(void)catchup_timer_jiffies(base);

	__internal_add_timer(base, timer);

	/*
@@ -415,8 +417,10 @@ static void internal_add_timer(struct tvec_base *base, struct timer_list *timer) 
	 */

	if (!tbase_get_deferrable(timer->base)) {

		if (!base->active_timers++ ||

		    time_before(timer->expires, base->next_timer))

		    time_before(timer->expires, base->next_timer)) {

			base->next_timer = timer->expires;

			leftmost = 1;

		}

	}

	base->all_timers++;
@@ -433,7 +437,7 @@ static void internal_add_timer(struct tvec_base *base, struct timer_list *timer) 
	 * require special care against races with idle_cpu(), lets deal

	 * with that later.

	 */

	if (!tbase_get_deferrable(timer->base) || tick_nohz_full_cpu(base->cpu))

	if (leftmost || tick_nohz_full_cpu(base->cpu))

		wake_up_nohz_cpu(base->cpu);

}