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

From: Rafael J. Wysocki
Date: Thu Aug 09 2018 - 13:10:42 EST


From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

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)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
kernel/sched/idle.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-pm/kernel/sched/idle.c
===================================================================
--- linux-pm.orig/kernel/sched/idle.c
+++ linux-pm/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();