1 files changed, 13 insertions, 0 deletions
diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c
index 2be6b9112808..6d184fae0ad1 100644
--- a/mm/memcontrol-v1.c
+++ b/mm/memcontrol-v1.c
@@ -490,6 +490,19 @@ static void mem_cgroup_threshold(struct mem_cgroup *memcg)
 }
 
 /* Cgroup1: threshold notifications & softlimit tree updates */
+
+/*
+ * Per memcg event counter is incremented at every pagein/pageout. With THP,
+ * it will be incremented by the number of pages. This counter is used
+ * to trigger some periodic events. This is straightforward and better
+ * than using jiffies etc. to handle periodic memcg event.
+ */
+enum mem_cgroup_events_target {
+	MEM_CGROUP_TARGET_THRESH,
+	MEM_CGROUP_TARGET_SOFTLIMIT,
+	MEM_CGROUP_NTARGETS,
+};
+
 struct memcg1_events_percpu {
 	unsigned long nr_page_events;
 	unsigned long targets[MEM_CGROUP_NTARGETS];