From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [PATCH] block: BARRIER request should imply SYNC Date: Thu, 17 Jun 2010 09:34:29 +0200 Message-ID: <4C19D005.8090703@kernel.dk> References: <20100617065416.GA19903@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: swhiteho@redhat.com, chris.mason@oracle.com, linux-fsdevel@vger.kernel.org To: Christoph Hellwig Return-path: Received: from 0122700014.0.fullrate.dk ([95.166.99.235]:52923 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752249Ab0FQHeb (ORCPT ); Thu, 17 Jun 2010 03:34:31 -0400 In-Reply-To: <20100617065416.GA19903@lst.de> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On 2010-06-17 08:54, Christoph Hellwig wrote: > > A barrier request should by defintion have priority in get_request > and let the queue be unplugged immediately as it's blocking all forward > progress due to the queue draining. > > Most filesystems already get this implicitly by the way how submit_bh > treats the buffer_ordered flag, and gfs2 sets it explicitly. But btrfs > and XFS are still forgetting to set the flag, as is blkdev_issue_flush > and some places in DM/MD. > > For XFS on metadata heavy workloads this gives a consistent speedup > in the 2-3% range. Thanks Christoph, applied. -- Jens Axboe