mm: introduce zone_reclaim struct

Add zone_reclam_stat struct for later enhancement.

A later patch uses this.  This patch doesn't any behavior change (yet).

Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: 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>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 7bf22e0..5675b30 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3523,10 +3523,10 @@
 			INIT_LIST_HEAD(&zone->lru[l].list);
 			zone->lru[l].nr_scan = 0;
 		}
-		zone->recent_rotated[0] = 0;
-		zone->recent_rotated[1] = 0;
-		zone->recent_scanned[0] = 0;
-		zone->recent_scanned[1] = 0;
+		zone->reclaim_stat.recent_rotated[0] = 0;
+		zone->reclaim_stat.recent_rotated[1] = 0;
+		zone->reclaim_stat.recent_scanned[0] = 0;
+		zone->reclaim_stat.recent_scanned[1] = 0;
 		zap_zone_vm_stats(zone);
 		zone->flags = 0;
 		if (!size)