From: Jan Kara Subject: Re: [PATCH 3/3] ext3: Avoid starting a transaction in writepage when not necessary Date: Mon, 30 Mar 2009 15:22:08 +0200 Message-ID: <20090330132208.GA30897@duck.suse.cz> References: <1238185471-31152-1-git-send-email-tytso@mit.edu> <1238185471-31152-2-git-send-email-tytso@mit.edu> <1238185471-31152-3-git-send-email-tytso@mit.edu> <1238185471-31152-4-git-send-email-tytso@mit.edu> <20090327222346.GJ31071@duck.suse.cz> <20090327230341.GF5176@mit.edu> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="liOOAslEiF7prFVr" To: Theodore Tso , Linux Kernel Developers List , Ext4 Developers List Return-path: Received: from cantor2.suse.de ([195.135.220.15]:34095 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751043AbZC3NWM (ORCPT ); Mon, 30 Mar 2009 09:22:12 -0400 Content-Disposition: inline In-Reply-To: <20090327230341.GF5176@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: --liOOAslEiF7prFVr Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri 27-03-09 19:03:41, Theodore Tso wrote: > On Fri, Mar 27, 2009 at 11:23:46PM +0100, Jan Kara wrote: > > On Fri 27-03-09 16:24:31, Theodore Ts'o wrote: > > > From: Jan Kara > > > > > > We don't have to start a transaction in writepage() when all the blocks > > > are a properly allocated. Even in ordered mode either the data has been > > > written via write() and they are thus already added to transaction's list > > > or the data was written via mmap and then it's random in which transaction > > > they get written anyway. > > > > > > This should help VM to pageout dirty memory without blocking on transaction > > > commits. > > > > > > Signed-off-by: Jan Kara > > > Signed-off-by: "Theodore Ts'o" > > Please, use the patch below instead (and I'd also wait a few days for > > Mingo to check whether it also helps him). It also changes data=writeback > > mode in the same way and it adheres to coding style... > > FYI, Looks like Linus has already cherry-picked your first patch from > LKML and dropped it into mainline. My other two patches haven't gone > in yet as far as I can tell. > > So we'll need to do a delta patch that has the differences from your > new patch and what Linus has already pulled into mainline. Thanks for letting me know. Attached is a rediff against current Linus's tree. Honza -- Jan Kara SUSE Labs, CR --liOOAslEiF7prFVr Content-Type: text/x-patch; charset=us-ascii Content-Disposition: attachment; filename="0001-ext3-Avoid-starting-a-transaction-in-writepage-when.patch" >From f53cf013259b9c782b79f4c1be49d5961884f867 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Mon, 30 Mar 2009 15:14:28 +0200 Subject: [PATCH] ext3: Avoid starting a transaction in writepage when not necessary This does the same as commit 9e80d407736161d9b8b0c5a0d44f786e44c322ea (avoid starting a transaction when no block allocation is needed) but for data=writeback mode of ext3. We also cleanup the data=ordered case a bit to stick to coding style... Signed-off-by: Jan Kara --- fs/ext3/inode.c | 23 ++++++++++++++++++----- 1 files changed, 18 insertions(+), 5 deletions(-) diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c index 4a09ff1..70c86b0 100644 --- a/fs/ext3/inode.c +++ b/fs/ext3/inode.c @@ -1512,12 +1512,16 @@ static int ext3_ordered_writepage(struct page *page, if (!page_has_buffers(page)) { create_empty_buffers(page, inode->i_sb->s_blocksize, (1 << BH_Dirty)|(1 << BH_Uptodate)); - } else if (!walk_page_buffers(NULL, page_buffers(page), 0, PAGE_CACHE_SIZE, NULL, buffer_unmapped)) { - /* Provide NULL instead of get_block so that we catch bugs if buffers weren't really mapped */ - return block_write_full_page(page, NULL, wbc); + page_bufs = page_buffers(page); + } else { + page_bufs = page_buffers(page); + if (!walk_page_buffers(NULL, page_bufs, 0, PAGE_CACHE_SIZE, + NULL, buffer_unmapped)) { + /* Provide NULL get_block() to catch bugs if buffers + * weren't really mapped */ + return block_write_full_page(page, NULL, wbc); + } } - page_bufs = page_buffers(page); --liOOAslEiF7prFVr--