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[PATCH] find_lock_page(): call __lock_page() directly.

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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>
This commit is contained in:
Nikita Danilov 2006-01-06 00:11:08 -08:00 committed by Linus Torvalds
parent a226f6c899
commit bbfbb7cec9
1 changed files with 3 additions and 2 deletions
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5
mm/filemap.c
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@ -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;