memcg: use correct scan number at reclaim

Even when page reclaim is under mem_cgroup, # of scan page is determined by
status of global LRU. Fix that.
Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/vmscan.c

@@ -1469,7 +1469,7 @@ static void shrink_zone(int priority, struct zone *zone,
 		int file = is_file_lru(l);
 		int scan;
 
-		scan = zone_page_state(zone, NR_LRU_BASE + l);
+		scan = zone_nr_pages(zone, sc, l);
 		if (priority) {
 			scan >>= priority;
 			scan = (scan * percent[file]) / 100;