X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=blobdiff_plain;f=mm%2Fvmscan.c;h=777af57fd8c8c80971d7abaf4edb974e360288c9;hp=fbcac3bdcf1965c3997966ffb5b3979f33684290;hb=9a1607071c293e48b08bd703733480b1d55c7b93;hpb=41e20983fe553b39bc2b00e07c7a379f0c86a4bc

diff --git a/mm/vmscan.c b/mm/vmscan.c
index fbcac3b..777af57 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -544,6 +544,16 @@ redo:
 		 */
 		lru = LRU_UNEVICTABLE;
 		add_page_to_unevictable_list(page);
+		/*
+		 * When racing with an mlock clearing (page is
+		 * unlocked), make sure that if the other thread does
+		 * not observe our setting of PG_lru and fails
+		 * isolation, we see PG_mlocked cleared below and move
+		 * the page back to the evictable list.
+		 *
+		 * The other side is TestClearPageMlocked().
+		 */
+		smp_mb();
 	}
 
 	/*