refcount of the "victim" should be decremented before exiting the loop.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/memcontrol.c

@@ -1133,8 +1133,10 @@ static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
 				 * anything, it might because there are
 				 * no reclaimable pages under this hierarchy
 				 */
-				if (!check_soft || !total)
+				if (!check_soft || !total) {
+					css_put(&victim->css);
 					break;
+				}
 				/*
 				 * We want to do more targetted reclaim.
 				 * excess >> 2 is not to excessive so as to
@@ -1142,8 +1144,10 @@ static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
 				 * coming back to reclaim from this cgroup
 				 */
 				if (total >= (excess >> 2) ||
-					(loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
+					(loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) {
+					css_put(&victim->css);
 					break;
+				}
 			}
 		}
 		if (!mem_cgroup_local_usage(&victim->stat)) {