[PATCH] memcg: mark mem_cgroup_page_stat() underflow unlikely

[Greg Thelen]

Add unlikely() to indicate that underflow of per-cpu counter
sum is not expected.

The underflow is already handled, but should have been
marked unlikely.

Reported-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
Signed-off-by: Greg Thelen <gthelen@xxxxxxxxxx>
---
 mm/memcontrol.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index ed070d0..e8fbade 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1393,7 +1393,7 @@ unsigned long mem_cgroup_page_stat(struct mem_cgroup *mem,
 	 * value.  This function returns an unsigned value, so round it up to
 	 * zero to avoid returning a very large value.
 	 */
-	if (value < 0)
+	if (unlikely(value < 0))
 		value = 0;
 
 	put_online_cpus();
-- 
1.7.3.1

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