Messages in this thread Patch in this message | | | From | Mel Gorman <> | Subject | [PATCH 15/17] mm: Do not use unnecessary atomic operations when adding pages to the LRU | Date | Thu, 1 May 2014 09:44:46 +0100 |
| |
When adding pages to the LRU we clear the active bit unconditionally. As the page could be reachable from other paths we cannot use unlocked operations without risk of corruption such as a parallel mark_page_accessed. This patch test if is necessary to clear the atomic flag before using an atomic operation. In the unlikely even this races with mark_page_accesssed the consequences are simply that the page may be promoted to the active list that might have been left on the inactive list before the patch. This is a marginal consequence.
Signed-off-by: Mel Gorman <mgorman@suse.de> --- include/linux/swap.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/include/linux/swap.h b/include/linux/swap.h index da8a250..395dcab 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -329,13 +329,15 @@ extern void add_page_to_unevictable_list(struct page *page); */ static inline void lru_cache_add_anon(struct page *page) { - ClearPageActive(page); + if (PageActive(page)) + ClearPageActive(page); __lru_cache_add(page); } static inline void lru_cache_add_file(struct page *page) { - ClearPageActive(page); + if (PageActive(page)) + ClearPageActive(page); __lru_cache_add(page); } -- 1.8.4.5
| |