memcg: fix memory.memsw.usage_in_bytes for root cgroup

A memory cgroup has a memory.memsw.usage_in_bytes file.  It shows the sum
of the usage of pages and swapents in the cgroup.  Presently the root
cgroup's memsw.usage_in_bytes shows the wrong value - the number of
swapents are not added.

So take MEM_CGROUP_STAT_SWAPOUT into account.

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e0c2066495e3..7b5b108c1c6b 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2542,6 +2542,7 @@ static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
                         val += idx_val;
                         mem_cgroup_get_recursive_idx_stat(mem,
                                 MEM_CGROUP_STAT_SWAPOUT, &idx_val);
+                        val += idx_val;
                         val <<= PAGE_SHIFT;
                 } else
                         val = res_counter_read_u64(&mem->memsw, name);