From: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Date: Thu, 13 Jan 2011 23:47:43 +0000 (-0800)
Subject: memcg: fix memory migration of shmem swapcache
X-Git-Tag: v2.6.38-rc1~74
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=50de1dd967d4ba3b8a90ebe7a4f5feca24191317;p=pandora-kernel.git

memcg: fix memory migration of shmem swapcache

In the current implementation mem_cgroup_end_migration() decides whether
the page migration has succeeded or not by checking "oldpage->mapping".

But if we are tring to migrate a shmem swapcache, the page->mapping of it
is NULL from the begining, so the check would be invalid.  As a result,
mem_cgroup_end_migration() assumes the migration has succeeded even if
it's not, so "newpage" would be freed while it's not uncharged.

This patch fixes it by passing mem_cgroup_end_migration() the result of
the page migration.

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

Reading git-diff-tree failed