Messages in this thread | | | Date | Sun, 11 Oct 2015 20:12:39 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH] timer: Lazily wakup nohz CPU when adding new timer. |
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On Mon, 28 Sep 2015, Yunhong Jiang wrote: > static void internal_add_timer(struct tvec_base *base, struct timer_list *timer) > { > + bool kick_nohz = false; > + > /* Advance base->jiffies, if the base is empty */ > if (!base->all_timers++) > base->timer_jiffies = jiffies; > @@ -424,9 +426,17 @@ static void internal_add_timer(struct tvec_base *base, struct timer_list *timer) > */ > if (!(timer->flags & TIMER_DEFERRABLE)) { > if (!base->active_timers++ || > - time_before(timer->expires, base->next_timer)) > + time_before(timer->expires, base->next_timer)) { > base->next_timer = timer->expires; > - } > + /* > + * CPU in dynticks need reevaluate the timer wheel > + * if newer timer added with next_timer updated. > + */ > + if (base->nohz_active) > + kick_nohz = true; > + } > + } else if (base->nohz_active && tick_nohz_full_cpu(base->cpu)) > + kick_nohz = true;
Why do you want to kick the other cpu when a deferrable timer got added?
Thanks,
tglx
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