From: "Darrick J. Wong" Subject: Re: [RFC v2] ext4: Don't send extra barrier during fsync if there are no dirty pages. Date: Fri, 6 Aug 2010 00:04:24 -0700 Message-ID: <20100806070424.GD2109@tux1.beaverton.ibm.com> References: <20100429235102.GC15607@tux1.beaverton.ibm.com> <1272934667.2544.3.camel@mingming-laptop> <4BE02C45.6010608@redhat.com> <1273002566.3755.10.camel@mingming-laptop> <20100629205102.GM15515@tux1.beaverton.ibm.com> <20100805164008.GH2901@thunk.org> <20100805164504.GI2901@thunk.org> Reply-To: djwong@us.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: "Ted Ts'o" , Mingming Cao , Ric Wheeler , linux-ext4 , linux-kernel , Ke Return-path: Received: from e4.ny.us.ibm.com ([32.97.182.144]:50341 "EHLO e4.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754560Ab0HFHE1 (ORCPT ); Fri, 6 Aug 2010 03:04:27 -0400 Content-Disposition: inline In-Reply-To: <20100805164504.GI2901@thunk.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Thu, Aug 05, 2010 at 12:45:04PM -0400, Ted Ts'o wrote: > P.S. If it wasn't clear, I'm still in favor of trying to coordinate > barriers across the whole file system, since that is much more likely > to help use cases that arise in real life. Ok. I have a rough sketch of a patch to do that, and I was going to send it out today, but the test machine caught on fire while I was hammering it with the fsync tests one last time and ... yeah. I'm fairly sure the patch didn't cause the fire, but I'll check anyway after I finish cleaning up. "[PATCH] ext4: Don't set my machine ablaze with barrier requests" :P (The patch did seem to cut barrier requests counts by about 20% though the impact on performance was pretty small.) --D