diff --git a/mm/compaction.c b/mm/compaction.c
index db289225193d..b99be5ca0000 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -2084,8 +2084,10 @@ static isolate_migrate_t isolate_migratepages(struct compact_control *cc)
 }
 
 /*
- * order == -1 is expected when compacting via
- * /proc/sys/vm/compact_memory
+ * order == -1 is expected when compacting proactively via
+ * 1. /proc/sys/vm/compact_memory
+ * 2. /sys/devices/system/node/nodex/compact
+ * 3. /proc/sys/vm/compaction_proactiveness
  */
 static inline bool is_via_compact_memory(int order)
 {