Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751939Ab0HSIxy (ORCPT ); Thu, 19 Aug 2010 04:53:54 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:51962 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751530Ab0HSIxw (ORCPT ); Thu, 19 Aug 2010 04:53:52 -0400 Date: Thu, 19 Aug 2010 04:53:49 -0400 From: Christoph Hellwig To: "Darrick J. Wong" Cc: Christoph Hellwig , "Ted Ts'o" , Mingming Cao , Ric Wheeler , linux-ext4 , linux-kernel , Keith Mannthey , Mingming Cao , Tejun Heo Subject: Re: [RFC v3] ext4: Combine barrier requests coming from fsync Message-ID: <20100819085349.GA8782@infradead.org> References: <4BE02C45.6010608@redhat.com> <1273002566.3755.10.camel@mingming-laptop> <20100629205102.GM15515@tux1.beaverton.ibm.com> <20100805164008.GH2901@thunk.org> <20100805164504.GI2901@thunk.org> <20100806070424.GD2109@tux1.beaverton.ibm.com> <20100809195324.GG2109@tux1.beaverton.ibm.com> <20100809210723.GA28171@infradead.org> <20100816161433.GK2109@tux1.beaverton.ibm.com> <20100819020734.GL2109@tux1.beaverton.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100819020734.GL2109@tux1.beaverton.ibm.com> User-Agent: Mutt/1.5.20 (2009-08-17) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1254 Lines: 25 On Wed, Aug 18, 2010 at 07:07:34PM -0700, Darrick J. Wong wrote: > Oddly, I ran the entire suite of tests against a larger set of machines, and > with Tejun's RFC patchset I didn't see nearly as much of an improvement. I > have been trying to put together a new tree based on "replace barrier with > sequenced flush" and Christoph's "explicitly flush/FUA" patch sets, though I've > gotten lost in the weeds. :( Tejun's patches don't allow concurrent cache flushes to happen, while my patch did. Tejun said there are drivers that can't handly empty flushes with a bio attached, making this nessecary. Tejun, any idea what drivers that would be? > I also experienced some sort of crash with Tejun's relaxed barrier patch on one > of my systems. I was hitting the BUG_ON in drivers/scsi/scsi_lib.c, line 1115. My kernel source doesn't have a BUG_ON line there, but only one two lines above. A req->nr_phys_segments that's zero sounds a bit like empty flush requests, I'll need to look into it again. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/