---

yaml
---
r: 332345
b: refs/heads/master
c: d741c9c
h: refs/heads/master
i:
  332343: de7410c
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 314e51b9851b4f4e8ab302243ff5a6fc6147f379
+refs/heads/master: d741c9cdeee6a569dae0dbbaf028065402955b59

trunk/mm/swap.c

@@ -446,13 +446,22 @@ void mark_page_accessed(struct page *page)
 }
 EXPORT_SYMBOL(mark_page_accessed);
 
+/*
+ * Order of operations is important: flush the pagevec when it's already
+ * full, not when adding the last page, to make sure that last page is
+ * not added to the LRU directly when passed to this function. Because
+ * mark_page_accessed() (called after this when writing) only activates
+ * pages that are on the LRU, linear writes in subpage chunks would see
+ * every PAGEVEC_SIZE page activated, which is unexpected.
+ */
 void __lru_cache_add(struct page *page, enum lru_list lru)
 {
 	struct pagevec *pvec = &get_cpu_var(lru_add_pvecs)[lru];
 
 	page_cache_get(page);
-	if (!pagevec_add(pvec, page))
+	if (!pagevec_space(pvec))
 		__pagevec_lru_add(pvec, lru);
+	pagevec_add(pvec, page);
 	put_cpu_var(lru_add_pvecs);
 }
 EXPORT_SYMBOL(__lru_cache_add);