Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754496Ab1EaKhR (ORCPT ); Tue, 31 May 2011 06:37:17 -0400 Received: from mx1.fusionio.com ([66.114.96.30]:42494 "EHLO mx1.fusionio.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753069Ab1EaKhP (ORCPT ); Tue, 31 May 2011 06:37:15 -0400 X-ASG-Debug-ID: 1306838234-03d6a512ab20c40001-xx1T2L X-Barracuda-Envelope-From: JAxboe@fusionio.com Message-ID: <4DE4C4D7.9060107@fusionio.com> Date: Tue, 31 May 2011 12:37:11 +0200 From: Jens Axboe MIME-Version: 1.0 To: Namhyung Kim CC: Christoph Hellwig , Mike Snitzer , "linux-kernel@vger.kernel.org" , Tejun Heo Subject: Re: [PATCH 1/2] blktrace: treat flush as barrier References: <1306501883-23498-1-git-send-email-namhyung@gmail.com> <20110527131237.GA27647@infradead.org> <1306509182.1351.1.camel@leonhard> <4DE006C5.4010906@fusionio.com> <20110527202747.GA4803@infradead.org> <1306548581.1679.12.camel@leonhard> X-ASG-Orig-Subj: Re: [PATCH 1/2] blktrace: treat flush as barrier In-Reply-To: <1306548581.1679.12.camel@leonhard> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-Barracuda-Connect: mail1.int.fusionio.com[10.101.1.21] X-Barracuda-Start-Time: 1306838234 X-Barracuda-URL: http://10.101.1.180:8000/cgi-mod/mark.cgi X-Barracuda-Spam-Score: 0.00 X-Barracuda-Spam-Status: No, SCORE=0.00 using per-user scores of TAG_LEVEL=1000.0 QUARANTINE_LEVEL=1000.0 KILL_LEVEL=9.0 tests= X-Barracuda-Spam-Report: Code version 3.2, rules version 3.2.2.65189 Rule breakdown below pts rule name description ---- ---------------------- -------------------------------------------------- Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1285 Lines: 34 On 2011-05-28 04:09, Namhyung Kim wrote: > 2011-05-27 (금), 16:27 -0400, Christoph Hellwig: >> On Fri, May 27, 2011 at 10:17:09PM +0200, Jens Axboe wrote: >>> Agree on Christophs comments, we should not pretend they are the same >>> (since they are not). Since flush is a request on its own, F works >>> nicely. For FUA it's associated with a write, so F should work there too >>> indicating Write Fua (and easily humanly parsed as that, or Write >>> Flush). WU would look confusing. >> >> REQ_FLUSH can also be set on a write bio, it only gets split at the >> request level. And even there we're at least pondering allowing it >> to stay as part of the write for some paravirtualized storage protocols. >> > > Hi, > > AFAIK FLUSH always precedes WRITE and then followed by FUA, so how about > using the same F for both of them and distinguishing by position? > > - WRITE: W > - WRITE_FLUSH: FW > - WRITE_FUA: WF > - WRITE_FLUSH_FUA: FWF That looks fine. 'U' would be an illogical choice. -- Jens Axboe -- 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/