From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Chinner Subject: Re: [Lsf] IO less throttling and cgroup aware writeback (Was: Re: Preliminary Agenda and Activities for LSF) Date: Fri, 1 Apr 2011 18:23:48 +1100 Message-ID: <20110401072348.GD6957@dastard> References: <20110330041802.GA20849@dastard> <20110330153757.GD1291@redhat.com> <20110330222002.GB20849@dastard> <20110331141637.GA11139@redhat.com> <1301581251-sup-987@think> <20110331221425.GB2904@dastard> <20110401013424.GA17928@redhat.com> <20110401043605.GA6957@dastard> <20110401063254.GA28242@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Vivek Goyal , James Bottomley , lsf , linux-fsdevel To: Christoph Hellwig Return-path: Received: from ipmail07.adl2.internode.on.net ([150.101.137.131]:32015 "EHLO ipmail07.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754921Ab1DAHXv (ORCPT ); Fri, 1 Apr 2011 03:23:51 -0400 Content-Disposition: inline In-Reply-To: <20110401063254.GA28242@infradead.org> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Fri, Apr 01, 2011 at 02:32:54AM -0400, Christoph Hellwig wrote: > On Fri, Apr 01, 2011 at 03:36:05PM +1100, Dave Chinner wrote: > > > If that's a concern, > > > can filesystem mark that bio (REQ_META?) and throttling logic can possibly > > > let these bio pass through. > > > > We already tag most metadata IO in this way. > > Actually we don't tag any I/O that way right now. That's mostly > because REQ_META assumes it's synchronous I/O and cfg and the block > layer give id additional priority, while in XFS metadata writes > are mostly asynchronous. We'll need a properly defined REQ_META > to use it, which currently is not the case. Oh, I misread the code in _xfs_buf_read that fiddles with _XBF_RUN_QUEUES. That flag is dead then, as is the XBF_LOG_BUFFER code which appears to have been superceded by the new XBF_ORDERED code. Definitely needs cleaning up. Cheers, Dave. -- Dave Chinner david@fromorbit.com