Commit 1ca8ec53 authored Jan 27, 2016 by Wanpeng Li Committed by Thomas Gleixner Jan 27, 2016

tick/nohz: Set the correct expiry when switching to nohz/lowres mode



commit 0ff53d09 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 0ff53d09 "tick: sched: Force tick interrupt and get rid of softirq magic"
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1453893967-3458-1-git-send-email-wanpeng.li@hotmail.com


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

parent d7023e62

kernel/time/tick-sched.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -995,9 +995,9 @@ 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);
		}

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