Recently this patch came in:
commit d689fe222a858c767cb8594faf280048e532b53f Author: Thomas Gleixner tglx@linutronix.de Date: Wed Nov 13 21:01:57 2013 +0100
NOHZ: Check for nohz active instead of nohz enabled
and introduced a bug here. tick_nohz_active is initialized to zero and we are returning from this routine if it is zero. And hence we will never be able to cross this check. Actually this should not have been changed by above patch and should have stayed to tick_nohz_enabled.
Fix it.
Cc: stable@vger.kernel.org # 3.13+ Signed-off-by: Viresh Kumar viresh.kumar@linaro.org ---
Some discussions already happened here:
https://lkml.org/lkml/2014/4/9/243 https://lkml.org/lkml/2014/4/9/346
kernel/time/tick-sched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index dd35b55..059e1eb 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -969,7 +969,7 @@ static void tick_nohz_switch_to_nohz(void) struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched); ktime_t next;
- if (!tick_nohz_active) + if (!tick_nohz_enabled) return;
local_irq_disable();