From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Date: Thu, 9 Aug 2018 17:08:34 +0000 (+0200)
Subject: sched: idle: Avoid retaining the tick when it has been stopped
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=7059b36636beab57c3c43c62104483e5449bee95;p=linux.git

sched: idle: Avoid retaining the tick when it has been stopped

If the tick has been stopped already, but the governor has not asked to
stop it (which it can do sometimes), the idle loop should invoke
tick_nohz_idle_stop_tick(), to let tick_nohz_stop_tick() take care
of this case properly.

Fixes: 554c8aa8ecad (sched: idle: Select idle state before stopping the tick)
Cc: 4.17+ <stable@vger.kernel.org> # 4.17+
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 1a3e9bddd17b6..16f84142f2f49 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -190,7 +190,7 @@ static void cpuidle_idle_call(void)
 		 */
 		next_state = cpuidle_select(drv, dev, &stop_tick);
 
-		if (stop_tick)
+		if (stop_tick || tick_nohz_tick_stopped())
 			tick_nohz_idle_stop_tick();
 		else
 			tick_nohz_idle_retain_tick();