1 files changed, 9 insertions, 1 deletions
diff --git a/mm/mlock.c b/mm/mlock.c
index 7debb4f..bd34b3a 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -110,7 +110,15 @@ void munlock_vma_page(struct page *page)
 	if (TestClearPageMlocked(page)) {
 		dec_zone_page_state(page, NR_MLOCK);
 		if (!isolate_lru_page(page)) {
-			int ret = try_to_munlock(page);
+			int ret = SWAP_AGAIN;
+
+			/*
+			 * Optimization: if the page was mapped just once,
+			 * that's our mapping and we don't need to check all the
+			 * other vmas.
+			 */
+			if (page_mapcount(page) > 1)
+				ret = try_to_munlock(page);
 			/*
 			 * did try_to_unlock() succeed or punt?
 			 */