From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id p74AaITZ064269 for ; Thu, 4 Aug 2011 05:36:18 -0500 Received: from mx2.suse.de (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id BC3981877DF2 for ; Thu, 4 Aug 2011 03:36:17 -0700 (PDT) Received: from mx2.suse.de (cantor2.suse.de [195.135.220.15]) by cuda.sgi.com with ESMTP id pbwt7VWD7je82ppG for ; Thu, 04 Aug 2011 03:36:17 -0700 (PDT) Date: Thu, 4 Aug 2011 12:36:16 +0200 From: Jan Kara Subject: Re: [PATCH 0/2] Improve writeout pattern from xfs_flush_pages() Message-ID: <20110804103616.GF17196@quack.suse.cz> References: <1312404545-15400-1-git-send-email-jack@suse.cz> <20110803214206.GA20477@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20110803214206.GA20477@infradead.org> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Christoph Hellwig Cc: linux-fsdevel@vger.kernel.org, Jan Kara , xfs@oss.sgi.com On Wed 03-08-11 17:42:06, Christoph Hellwig wrote: > On Wed, Aug 03, 2011 at 10:49:03PM +0200, Jan Kara wrote: > > > > Hi, > > > > at one of customer's machines, I've spotted an issue that sync(1) called > > after writing a single huge file has been achieving rather low throughput. After > > debugging this with blktrace, I've found that the culprit was in flusher thread > > racing with page writeout happening from XFS sync code. The patches below helped > > that case. Although they are not a complete solution, I belive they are useful > > anyway so please consider merging them... > > We currently have three calls to xfs_flush_pages with XBF_ASYNC set: > > - xfs_setattr_size > - xfs_sync_inode_data > - xfs_release > > The first one actually is a synchronous writeout, just implemented in > a rather odd way by doing the xfs_ioend_wait right after it, so your > change is actively harmful for it. Oh, right. BTW cannot be truncate livelocked on a busy file because of that xfs_ioend_wait()? > The second is only called from xfs_flush_worker, which is the workqueue > offload when we hit ENOSPC. I can see how this might race with the > writeback code, but the correct fix is to replace it with a call to > writeback_inodes_sb(_if_idle) on that one is fixed to do a trylock on > s_umount and thus won't deadlock. OK. > The third one is opportunistic writeout if a file got truncated down on > final release. filemap_flush probably is fine here, but there's no need > for a range version. If you replace it with filemap_flush please also > kill the useless wrapper while you're at it. Do you mean xfs_flush_pages()? OK, I can do that. Thanks for having a look. Honza -- Jan Kara SUSE Labs, CR _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs