memcg: fix account leak at failure of memsw acconting

Commit 4b53433468 ("memcg: clean up try_charge main loop") removes a
cancel of charge at case: memory charge-> success.  mem+swap charge->
failure.

This leaks usage of memory.  Fix it.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: <stable@kernel.org>	[2.6.36+]
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 4fcf47a..1eb1a04 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1832,6 +1832,7 @@ static int __mem_cgroup_do_charge(struct mem_cgroup *mem, gfp_t gfp_mask,
                if (likely(!ret))
                        return CHARGE_OK;
 
+               res_counter_uncharge(&mem->res, csize);
                mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw);
                flags |= MEM_CGROUP_RECLAIM_NOSWAP;
        } else