---

yaml
---
r: 272162
b: refs/heads/master
c: 21ee9f3
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 2f1da6421570d064a94e17190a4955c2df99794d
+refs/heads/master: 21ee9f398be209ccbb62929d35961ca1ed48eec3

trunk/mm/shmem.c

@@ -1068,6 +1068,12 @@ int shmem_lock(struct file *file, int lock, struct user_struct *user)
 		user_shm_unlock(inode->i_size, user);
 		info->flags &= ~VM_LOCKED;
 		mapping_clear_unevictable(file->f_mapping);
+		/*
+		 * Ensure that a racing putback_lru_page() can see
+		 * the pages of this mapping are evictable when we
+		 * skip them due to !PageLRU during the scan.
+		 */
+		smp_mb__after_clear_bit();
 		scan_mapping_unevictable_pages(file->f_mapping);
 	}
 	retval = 0;

trunk/mm/vmscan.c

@@ -633,13 +633,14 @@ void putback_lru_page(struct page *page)
 		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
+		 * When racing with an mlock or AS_UNEVICTABLE clearing
+		 * (page is unlocked) make sure that if the other thread
+		 * does not observe our setting of PG_lru and fails
+		 * isolation/check_move_unevictable_page,
+		 * we see PG_mlocked/AS_UNEVICTABLE cleared below and move
 		 * the page back to the evictable list.
 		 *
-		 * The other side is TestClearPageMlocked().
+		 * The other side is TestClearPageMlocked() or shmem_lock().
 		 */
 		smp_mb();
 	}