linux-kernel - [PATCH 2/2] vmstat: make vmstat

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Date:	Thu, 28 Jan 2016 18:17:46 +0100
From:	Michal Hocko <mhocko@...nel.org>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Cristopher Lameter <clameter@....com>,
	Mike Galbraith <mgalbraith@...e.com>, <linux-mm@...ck.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Michal Hocko <mhocko@...e.com>
Subject: [PATCH 2/2] vmstat: make vmstat_update deferrable

From: Michal Hocko <mhocko@...e.com>

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
context.

Acked-by: Christoph Lameter <cl@...ux.com>
Signed-off-by: Michal Hocko <mhocko@...e.com>
---
 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;
 
 	for_each_possible_cpu(cpu)
-		INIT_DELAYED_WORK(per_cpu_ptr(&vmstat_work, cpu),
+		INIT_DEFERRABLE_WORK(per_cpu_ptr(&vmstat_work, cpu),
 			vmstat_update);
 
 	if (!alloc_cpumask_var(&cpu_stat_off, GFP_KERNEL))
-- 
2.7.0.rc3