1 files changed, 6 insertions, 0 deletions

diff --git a/mm/mlock.c b/mm/mlock.c
index 79398200e423..74e5a6547c3d 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -64,6 +64,12 @@ void clear_page_mlock(struct page *page)
         mod_zone_page_state(page_zone(page), NR_MLOCK,
                             -hpage_nr_pages(page));
         count_vm_event(UNEVICTABLE_PGCLEARED);
+        /*
+         * The previous TestClearPageMlocked() corresponds to the smp_mb()
+         * in __pagevec_lru_add_fn().
+         *
+         * See __pagevec_lru_add_fn for more explanation.
+         */
         if (!isolate_lru_page(page)) {
                 putback_lru_page(page);
         } else {