memcg: add mm_vmscan_memcg_isolate tracepoint

Memcg also need to trace page isolation information as global reclaim.
This patch does it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index de54ea0..0576e9e 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -51,6 +51,8 @@
 
 #include <asm/uaccess.h>
 
+#include <trace/events/vmscan.h>
+
 struct cgroup_subsys mem_cgroup_subsys __read_mostly;
 #define MEM_CGROUP_RECLAIM_RETRIES	5
 struct mem_cgroup *root_mem_cgroup __read_mostly;
@@ -1007,6 +1009,10 @@
 	}
 
 	*scanned = scan;
+
+	trace_mm_vmscan_memcg_isolate(0, nr_to_scan, scan, nr_taken,
+				      0, 0, 0, mode);
+
 	return nr_taken;
 }