Commit bbfbb7ce authored Jan 06, 2006 by Nikita Danilov Committed by Linus Torvalds Jan 06, 2006

[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 <danilov@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent a226f6c8

mm/filemap.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -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;

Admin message