From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Date: Tue, 1 Feb 2011 23:52:45 +0000 (-0800)
Subject: memcg: fix event counting breakage from recent THP update
X-Git-Tag: v2.6.38-rc4~32
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=3751d60430fe4c26460a5ca8ad8672d32f93bcb1;p=linux.git

memcg: fix event counting breakage from recent THP update

Changes in e401f1761 ("memcg: modify accounting function for supporting
THP better") adds nr_pages to support multiple page size in
memory_cgroup_charge_statistics.

But counting the number of event nees abs(nr_pages) for increasing
counters.  This patch fixes event counting.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index fc75f34ba609..da53a252b259 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -612,8 +612,10 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
 	/* pagein of a big page is an event. So, ignore page size */
 	if (nr_pages > 0)
 		__this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGIN_COUNT]);
-	else
+	else {
 		__this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGOUT_COUNT]);
+		nr_pages = -nr_pages; /* for event */
+	}
 
 	__this_cpu_add(mem->stat->count[MEM_CGROUP_EVENTS], nr_pages);