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-rw-r--r--kernel/timer.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/kernel/timer.c b/kernel/timer.c
index accfd241b9e5..b75e7893be14 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -939,8 +939,15 @@ void add_timer_on(struct timer_list *timer, int cpu)
* with the timer by holding the timer base lock. This also
* makes sure that a CPU on the way to stop its tick can not
* evaluate the timer wheel.
+ *
+ * Spare the IPI for deferrable timers on idle targets though.
+ * The next busy ticks will take care of it. Except full dynticks
+ * require special care against races with idle_cpu(), lets deal
+ * with that later.
*/
- wake_up_nohz_cpu(cpu);
+ if (!tbase_get_deferrable(timer->base) || tick_nohz_full_cpu(cpu))
+ wake_up_nohz_cpu(cpu);
+
spin_unlock_irqrestore(&base->lock, flags);
}
EXPORT_SYMBOL_GPL(add_timer_on);