From: Dave Chinner Subject: Re: Filesystem writes on RAID5 too slow Date: Wed, 11 Dec 2013 11:27:53 +1100 Message-ID: <20131211002753.GD10988@dastard> References: <528A5C45.4080906@redhat.com> <20131119005740.GY6188@dastard> <20131121092606.GU11434@dastard> <20131121234116.GD6502@dastard> <20131210191803.GA31162@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Martin Boutin , "Kernel.org-Linux-RAID" , Eric Sandeen , "Kernel.org-Linux-EXT4" , xfs-oss To: Christoph Hellwig Return-path: Content-Disposition: inline In-Reply-To: <20131210191803.GA31162@infradead.org> Sender: linux-raid-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Tue, Dec 10, 2013 at 11:18:03AM -0800, Christoph Hellwig wrote: > > xfs: align initial file allocations correctly. > > > > From: Dave Chinner > > > > The function xfs_bmap_isaeof() is used to indicate that an > > allocation is occurring at or past the end of file, and as such > > should be aligned to the underlying storage geometry if possible. > > > > Commit 27a3f8f ("xfs: introduce xfs_bmap_last_extent") changed the > > behaviour of this function for empty files - it turned off > > allocation alignment for this case accidentally. Hence large initial > > allocations from direct IO are not getting correctly aligned to the > > underlying geometry, and that is cause write performance to drop in > > alignment sensitive configurations. > > > > Fix it by considering allocation into empty files as requiring > > aligned allocation again. > > Seems like this one didn't get picked up yet? I'm about to resend all my outstanding patches... Cheers, Dave. -- Dave Chinner david@fromorbit.com