memcg: add mem_cgroup_zone_nr_pages()

Introduce mem_cgroup_zone_nr_pages().  It is called by zone_nr_pages()
helper function.

This patch doesn't have any behavior change.

Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index b2bc06bffcfb..d958d624d3ae 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -139,6 +139,9 @@ static struct zone_reclaim_stat *get_reclaim_stat(struct zone *zone,
 static unsigned long zone_nr_pages(struct zone *zone, struct scan_control *sc,
                                    enum lru_list lru)
 {
+        if (!scan_global_lru(sc))
+                return mem_cgroup_zone_nr_pages(sc->mem_cgroup, zone, lru);
+
         return zone_page_state(zone, NR_LRU_BASE + lru);
 }