From c0950f56caf206fd241ab6f75add8455244af24d Mon Sep 17 00:00:00 2001
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Date: Wed, 27 Oct 2010 15:33:39 -0700
Subject: [PATCH] --- yaml --- r: 218530 b: refs/heads/master c:
 0c270f8f9988fb0d93ea214fdcff7ab90eb3d894 h: refs/heads/master v: v3

---
 [refs]                | 2 +-
 trunk/mm/memcontrol.c | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index 0eec231cbf8e..5dccfaf0d0dd 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 45531757b45cae0ce64c5aff08c2534d5a0fa3e7
+refs/heads/master: 0c270f8f9988fb0d93ea214fdcff7ab90eb3d894
diff --git a/trunk/mm/memcontrol.c b/trunk/mm/memcontrol.c
index 9be3cf8a5da4..0e3fdbd809c7 100644
--- a/trunk/mm/memcontrol.c
+++ b/trunk/mm/memcontrol.c
@@ -1485,7 +1485,8 @@ void mem_cgroup_update_file_mapped(struct page *page, int val)
 		SetPageCgroupFileMapped(pc);
 	} else {
 		__this_cpu_dec(mem->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
-		ClearPageCgroupFileMapped(pc);
+		if (!page_mapped(page)) /* for race between dec->inc counter */
+			ClearPageCgroupFileMapped(pc);
 	}
 
 done: