memcg: reclaim shouldn't change zone->recent_rotated statistics

memcg reclaim shouldn't change zone->recent_rotated statistics.  If
memcgroup reclaim changes zone statistics, global reclaim can get a bit
confused.
Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: NRik van Riel <riel@redhat.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/vmscan.c

@@ -1246,7 +1246,8 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
 	 * This helps balance scan pressure between file and anonymous
 	 * pages in get_scan_ratio.
 	 */
-	zone->recent_rotated[!!file] += pgmoved;
+	if (scan_global_lru(sc))
+		zone->recent_rotated[!!file] += pgmoved;
 
 	/*
 	 * Move the pages to the [file or anon] inactive list.