[PATCH 2/2] vmstat: make vmstat_update deferrable

From: Michal Hocko
Date: Thu Jan 28 2016 - 12:18:09 EST

From: Michal Hocko <mhocko@xxxxxxxx>

0eb77e988032 ("vmstat: make vmstat_updater deferrable again and shut
down on idle") made vmstat_shepherd deferrable. vmstat_update itself
is still useing standard timer which might interrupt idle task. This
is possible because "mm, vmstat: make quiet_vmstat lighter" removed
cancel_delayed_work from the quiet_vmstat. Change vmstat_work to
use DEFERRABLE_WORK to prevent from pointless wakeups from the idle

Acked-by: Christoph Lameter <cl@xxxxxxxxx>
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
mm/vmstat.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/vmstat.c b/mm/vmstat.c
index eb30bf45bd55..69537d2be6f6 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1512,7 +1512,7 @@ static void __init start_shepherd_timer(void)
int cpu;

- INIT_DELAYED_WORK(per_cpu_ptr(&vmstat_work, cpu),
+ INIT_DEFERRABLE_WORK(per_cpu_ptr(&vmstat_work, cpu),

if (!alloc_cpumask_var(&cpu_stat_off, GFP_KERNEL))