From b5be11329f8cb2cc1a4c3b33b6b8d096c6012895 Mon Sep 17 00:00:00 2001
From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Date: Mon, 12 May 2008 14:02:06 -0700
Subject: [PATCH] make vmstat cpu-unplug safe
When accessing cpu_online_map, we should prevent dynamic changing
of cpu_online_map by get_online_cpus().
Unfortunately, all_vm_events() doesn't do that.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Christoph Lameter <clameter@sgi.com>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/vmstat.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 1a32130b958c..db9eabb2c5b3 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -41,7 +41,9 @@ static void sum_vm_events(unsigned long *ret, cpumask_t *cpumask)
*/
void all_vm_events(unsigned long *ret)
{
+ get_online_cpus();
sum_vm_events(ret, &cpu_online_map);
+ put_online_cpus();
}
EXPORT_SYMBOL_GPL(all_vm_events);
--
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