From 78aaced3408141bb7c836f2db0ca435790399da5 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sat, 26 Feb 2011 14:09:14 -0500 Subject: ext4: don't lock the next page in write_cache_pages if not needed If we have accumulated a contiguous region of memory to be written out, and the next page can added to this region, don't bother locking (and then unlocking the page) before writing out the memory. In the unlikely event that the next page was being written back by some other CPU, we can also skip waiting that page to finish writeback. Signed-off-by: "Theodore Ts'o" --- fs/ext4/inode.c | 27 ++++++++++----------------- 1 file changed, 10 insertions(+), 17 deletions(-) (limited to 'fs/ext4') diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 617c9cbba18..c2e6af33823 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2761,6 +2761,16 @@ static int write_cache_pages_da(struct address_space *mapping, *done_index = page->index + 1; + /* + * If we can't merge this page, and we have + * accumulated an contiguous region, write it + */ + if ((mpd->next_page != page->index) && + (mpd->next_page != mpd->first_page)) { + mpage_da_map_and_submit(mpd); + goto ret_extent_tail; + } + lock_page(page); /* @@ -2784,24 +2794,7 @@ static int write_cache_pages_da(struct address_space *mapping, BUG_ON(PageWriteback(page)); - /* - * Can we merge this page to current extent? - */ if (mpd->next_page != page->index) { - /* - * Nope, we can't. So, we map - * non-allocated blocks and start IO - * on them - */ - if (mpd->next_page != mpd->first_page) { - mpage_da_map_and_submit(mpd); - /* - * skip rest of the page in the page_vec - */ - unlock_page(page); - goto ret_extent_tail; - } - /* * Start next extent of pages and blocks */ -- cgit v1.2.3