From: Wanpeng Li Date: Wed, 27 Jan 2016 11:26:07 +0000 (+0800) Subject: tick/nohz: Set the correct expiry when switching to nohz/lowres mode X-Git-Tag: firefly_0821_release~176^2~475^2~146 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=d024d46ec5203664fac872a20f7d75125db952da;p=firefly-linux-kernel-4.4.55.git tick/nohz: Set the correct expiry when switching to nohz/lowres mode commit 1ca8ec532fc2d986f1f4a319857bb18e0c9739b4 upstream. commit 0ff53d096422 sets the next tick interrupt to the last jiffies update, i.e. in the past, because the forward operation is invoked before the set operation. There is no resulting damage (yet), but we get an extra pointless tick interrupt. Revert the order so we get the next tick interrupt in the future. Fixes: commit 0ff53d096422 "tick: sched: Force tick interrupt and get rid of softirq magic" Signed-off-by: Wanpeng Li Cc: Peter Zijlstra Cc: Frederic Weisbecker Link: http://lkml.kernel.org/r/1453893967-3458-1-git-send-email-wanpeng.li@hotmail.com Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 7c7ec4515983..22c57e191a23 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -977,9 +977,9 @@ static void tick_nohz_switch_to_nohz(void) /* Get the next period */ next = tick_init_jiffy_update(); - hrtimer_forward_now(&ts->sched_timer, tick_period); hrtimer_set_expires(&ts->sched_timer, next); - tick_program_event(next, 1); + hrtimer_forward_now(&ts->sched_timer, tick_period); + tick_program_event(hrtimer_get_expires(&ts->sched_timer), 1); tick_nohz_activate(ts, NOHZ_MODE_LOWRES); }