1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index f952a07ce7a9..60e95872da29 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -42,6 +42,7 @@ enum mem_cgroup_stat_index {
         MEM_CGROUP_STAT_RSS,            /* # of pages charged as anon rss */
         MEM_CGROUP_STAT_RSS_HUGE,       /* # of pages charged as anon huge */
         MEM_CGROUP_STAT_FILE_MAPPED,    /* # of pages charged as file rss */
+        MEM_CGROUP_STAT_WRITEBACK,      /* # of pages under writeback */
         MEM_CGROUP_STAT_SWAP,           /* # of pages, swapped out */
         MEM_CGROUP_STAT_NSTATS,
 };