memcg: mem_cgroup_shrink_node_zone() doesn't need sc.nodemask

Currently mem_cgroup_shrink_node_zone() call shrink_zone() directly.  thus
it doesn't need to initialize sc.nodemask because shrink_zone() doesn't
use it at all.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Nishimura Daisuke <d-nishimura@mtf.biglobe.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 2912704..06ccda6 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1969,7 +1969,7 @@
 unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
 						gfp_t gfp_mask, bool noswap,
 						unsigned int swappiness,
-						struct zone *zone, int nid)
+						struct zone *zone)
 {
 	struct scan_control sc = {
 		.nr_to_reclaim = SWAP_CLUSTER_MAX,
@@ -1980,11 +1980,8 @@
 		.order = 0,
 		.mem_cgroup = mem,
 	};
-	nodemask_t nm  = nodemask_of_node(nid);
-
 	sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) |
 			(GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK);
-	sc.nodemask = &nm;
 
 	trace_mm_vmscan_memcg_softlimit_reclaim_begin(0,
 						      sc.may_writepage,