Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755597AbZCYVXZ (ORCPT ); Wed, 25 Mar 2009 17:23:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754177AbZCYVW4 (ORCPT ); Wed, 25 Mar 2009 17:22:56 -0400 Received: from accolon.hansenpartnership.com ([76.243.235.52]:60616 "EHLO accolon.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754842AbZCYVWz (ORCPT ); Wed, 25 Mar 2009 17:22:55 -0400 Subject: Re: Linux 2.6.29 From: James Bottomley To: Ric Wheeler Cc: Jeff Garzik , Jens Axboe , Linus Torvalds , Theodore Tso , Ingo Molnar , Alan Cox , Arjan van de Ven , Andrew Morton , Peter Zijlstra , Nick Piggin , David Rees , Jesper Krogh , Linux Kernel Mailing List In-Reply-To: <49CA9324.6010407@redhat.com> References: <20090324093245.GA22483@elte.hu> <20090324101011.6555a0b9@lxorguk.ukuu.org.uk> <20090324103111.GA26691@elte.hu> <20090324132032.GK5814@mit.edu> <20090324184549.GE32307@mit.edu> <49C93AB0.6070300@garzik.org> <20090325093913.GJ27476@kernel.dk> <49CA86BD.6060205@garzik.org> <20090325194341.GB27476@kernel.dk> <49CA8ADA.3040709@redhat.com> <49CA9114.3040205@garzik.org> <49CA9324.6010407@redhat.com> Content-Type: text/plain Date: Wed, 25 Mar 2009 21:22:50 +0000 Message-Id: <1238016170.3281.36.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 (2.22.3.1-1.fc9) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1284 Lines: 34 On Wed, 2009-03-25 at 16:25 -0400, Ric Wheeler wrote: > Jeff Garzik wrote: > > Ric Wheeler wrote:> And, as I am sure that you do know, to add insult > > to injury, FLUSH_CACHE > >> is per device (not file system). > >> > >> When you issue an fsync() on a disk with multiple partitions, you > >> will flush the data for all of its partitions from the write cache.... > > > > SCSI'S SYNCHRONIZE CACHE command already accepts an (LBA, length) > > pair. We could make use of that. > > > > And I bet we could convince T13 to add FLUSH CACHE RANGE, if we could > > demonstrate clear benefit. > > > > Jeff > > How well supported is this in SCSI? Can we try it out with a commodity > SAS drive? What do you mean by well supported? The way the SCSI standard is written, a device can do a complete cache flush when a range flush is requested and still be fully standards compliant. There's no easy way to tell if it does a complete cache flush every time other than by taking the firmware apart (or asking the manufacturer). James -- 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/