From: Jan Kara Subject: Re: [PATCH 0/11] Fix page_mkwrite() for blocksize < pagesize Date: Thu, 28 May 2009 11:36:01 +0200 Message-ID: <20090528093601.GF29199@duck.suse.cz> References: <1243429268-3028-1-git-send-email-jack@suse.cz> <20090527153358.GA19989@skywalker> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jan Kara , LKML , npiggin@suse.de, linux-ext4@vger.kernel.org To: "Aneesh Kumar K.V" Return-path: Received: from cantor.suse.de ([195.135.220.2]:53046 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754624AbZE1JgH (ORCPT ); Thu, 28 May 2009 05:36:07 -0400 Content-Disposition: inline In-Reply-To: <20090527153358.GA19989@skywalker> Sender: linux-ext4-owner@vger.kernel.org List-ID: Hi, On Wed 27-05-09 21:03:58, Aneesh Kumar K.V wrote: > On Wed, May 27, 2009 at 03:00:57PM +0200, Jan Kara wrote: > > > > patches below are an attempt to solve problems filesystems have with > > page_mkwrite() when blocksize < pagesize (see the changelog of the third patch > > for details). > > > > The series is against 2.6.30-rc7. The first two patches are just small cleanup > > and should be merged separately (Ted should have the ext4 cleanup rebased on > > top of current ext4 tree). For ext3 the fix is done in two phases, in the first > > we make it to correctly allocate space at page-fault time from page_mkwrite(). > > This has the disadvantage that under random mmaped writes, the file gets much > > more fragmented and performance of e.g. Berkeley DB drops by ~20%. Therefore > > in the second phase I've implemented delayed allocation for ext3 and blocks > > are just reserved during page_mkwrite time and really allocated only during > > writepage. This gets the performance back to original numbers for me. > > > > The patches should be fairly complete and sustained quite some testing. OTOH > > the area is kind of complex so please review them so that they can get merged. > > Thanks. > > Can you move patch 7 and patch 11 as the last two patches. That would > make sure we can push rest of the patches earlier. Rest of the patches > are needed for ext4 to fix some of the bugs we are seeing. For eg: > http://bugzilla.kernel.org/show_bug.cgi?id=12624 > http://bugzilla.kernel.org/show_bug.cgi?id=13369 OK, I think I can just move patches 3 and 5 to the beginning. That's all that should be needed for ext4. > I have few writepage patches also on top of your last series. Having > patch 7 and patch 11 as last two patches make sure we can get the rest > of the patches in ext4 patchqueue and get wider testing. Good point. I think Ted did the right thing and took just patches 3 and 5 to ext4 patch queue but I can reorder the patches for next time... Honza -- Jan Kara SUSE Labs, CR