memcg: make memcg's file mapped consistent with global VM

In global VM, FILE_MAPPED is used but memcg uses MAPPED_FILE.  This makes
grep difficult.  Replace memcg's MAPPED_FILE with FILE_MAPPED

And in global VM, mapped shared memory is accounted into FILE_MAPPED.
But memcg doesn't. fix it.
Note:
  page_is_file_cache() just checks SwapBacked or not.
  So, we need to check PageAnon.

Cc: Balbir Singh <balbir@in.ibm.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@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/rmap.c b/mm/rmap.c
index 98135db..278cd27 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -721,7 +721,7 @@
 {
 	if (atomic_inc_and_test(&page->_mapcount)) {
 		__inc_zone_page_state(page, NR_FILE_MAPPED);
-		mem_cgroup_update_mapped_file_stat(page, 1);
+		mem_cgroup_update_file_mapped(page, 1);
 	}
 }
 
@@ -753,8 +753,8 @@
 		__dec_zone_page_state(page, NR_ANON_PAGES);
 	} else {
 		__dec_zone_page_state(page, NR_FILE_MAPPED);
+		mem_cgroup_update_file_mapped(page, -1);
 	}
-	mem_cgroup_update_mapped_file_stat(page, -1);
 	/*
 	 * It would be tidy to reset the PageAnon mapping here,
 	 * but that might overwrite a racing page_add_anon_rmap