From: Nikita Danilov Date: Fri, 6 Jan 2006 08:11:08 +0000 (-0800) Subject: [PATCH] find_lock_page(): call __lock_page() directly. X-Git-Tag: firefly_0821_release~39672^2~252 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=bbfbb7cec9dd7266534b2b4b9c8be2fa425bbfc9;p=firefly-linux-kernel-4.4.55.git [PATCH] find_lock_page(): call __lock_page() directly. As find_lock_page() already checks with TestSetPageLocked() that page is locked, there is no need to call lock_page() that will try-lock page again (chances of page being unlocked in between are small). Call __lock_page() directly, this saves one atomic operation. Also, mark truncate-while-slept path as unlikely while we are here. (akpm: ug. But this is actually a common path for normal old read()s against a page which is under readahead I/O so ho-hum.) Signed-off-by: Nikita Danilov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/filemap.c b/mm/filemap.c index 6e1d08a2b8b9..4ef24a397684 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -555,11 +555,12 @@ repeat: page_cache_get(page); if (TestSetPageLocked(page)) { read_unlock_irq(&mapping->tree_lock); - lock_page(page); + __lock_page(page); read_lock_irq(&mapping->tree_lock); /* Has the page been truncated while we slept? */ - if (page->mapping != mapping || page->index != offset) { + if (unlikely(page->mapping != mapping || + page->index != offset)) { unlock_page(page); page_cache_release(page); goto repeat;