Commit-ID: 16d937f880312e3f47157d4d6d6ebf7e61523378 Gitweb: http://git.kernel.org/tip/16d937f880312e3f47157d4d6d6ebf7e61523378 Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> AuthorDate: Mon, 16 Dec 2013 10:32:01 -0800 Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> CommitDate: Tue, 25 Feb 2014 12:39:00 -0800 timers: Reduce future __run_timers() latency for newly emptied list The __run_timers() function currently steps through the list one jiffy at a time in order to update the timer wheel. However, if the timer wheel is empty, no adjustment is needed other than updating ->timer_jiffies. Therefore, if we just emptied the timer wheel, for example, by deleting the last timer, we should mark the timer wheel as being up to date. This marking will reduce (and perhaps eliminate) the jiffy-stepping that a future __run_timers() call will need to do in response to some future timer posting or migration. This commit therefore catches ->timer_jiffies for this case. Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx> Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Reviewed-by: Oleg Nesterov <oleg@xxxxxxxxxx> Reviewed-by: Steven Rostedt <rostedt@xxxxxxxxxxx> Tested-by: Mike Galbraith <bitbucket@xxxxxxxxx> --- kernel/timer.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/timer.c b/kernel/timer.c index c8bc709..dfac34f 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -688,6 +688,7 @@ detach_expired_timer(struct timer_list *timer, struct tvec_base *base) if (!tbase_get_deferrable(timer->base)) base->active_timers--; base->all_timers--; + (void)catchup_timer_jiffies(base); } static int detach_if_pending(struct timer_list *timer, struct tvec_base *base, @@ -703,6 +704,7 @@ static int detach_if_pending(struct timer_list *timer, struct tvec_base *base, base->next_timer = base->timer_jiffies; } base->all_timers--; + (void)catchup_timer_jiffies(base); return 1; } -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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