[PATCH] mm: simplify vmscan vs release refcounting

[linux-2.6-block.git] / mm / vmscan.c

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 8e477b1a48380ec92171c0d38c1c586cab5f243e..e21bab4deda65ab3c35bb40f0fbdce2c22a36222 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1083,29 +1083,26 @@ static int isolate_lru_pages(int nr_to_scan, struct list_head *src,
        int scan = 0;
 
        while (scan++ < nr_to_scan && !list_empty(src)) {
+               struct list_head *target;
                page = lru_to_page(src);
                prefetchw_prev_lru_page(page, src, flags);
 
                BUG_ON(!PageLRU(page));
 
                list_del(&page->lru);
-               if (unlikely(get_page_testone(page))) {
+               target = src;
+               if (likely(get_page_unless_zero(page))) {
                        /*
-                        * It is being freed elsewhere
+                        * Be careful not to clear PageLRU until after we're
+                        * sure the page is not being freed elsewhere -- the
+                        * page release code relies on it.
                         */
-                       __put_page(page);
-                       list_add(&page->lru, src);
-                       continue;
-               }
+                       ClearPageLRU(page);
+                       target = dst;
+                       nr_taken++;
+               } /* else it is being freed elsewhere */
 
-               /*
-                * Be careful not to clear PageLRU until after we're sure
-                * the page is not being freed elsewhere -- the page release
-                * code relies on it.
-                */
-               ClearPageLRU(page);
-               list_add(&page->lru, dst);
-               nr_taken++;
+               list_add(&page->lru, target);
        }
 
        *scanned = scan;