From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752121Ab1HSGeG (ORCPT ); Fri, 19 Aug 2011 02:34:06 -0400 Received: from mx1.fusionio.com ([66.114.96.30]:56657 "EHLO mx1.fusionio.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751378Ab1HSGeC (ORCPT ); Fri, 19 Aug 2011 02:34:02 -0400 X-ASG-Debug-ID: 1313735641-03d6a510a82f4580001-xx1T2L X-Barracuda-Envelope-From: JAxboe@fusionio.com Message-ID: <4E4E03D5.40404@fusionio.com> Date: Fri, 19 Aug 2011 08:33:57 +0200 From: Jens Axboe MIME-Version: 1.0 To: Shaohua Li CC: "teravest@google.com" , lkml , "Shi, Alex" Subject: Re: cfq-iosched: a regression References: <1313462826.27321.22.camel@sli10-conroe> X-ASG-Orig-Subj: Re: cfq-iosched: a regression In-Reply-To: <1313462826.27321.22.camel@sli10-conroe> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Barracuda-Connect: mail1.int.fusionio.com[10.101.1.21] X-Barracuda-Start-Time: 1313735641 X-Barracuda-URL: http://10.101.1.180:8000/cgi-mod/mark.cgi X-Barracuda-Bayes: INNOCENT GLOBAL 0.0000 1.0000 -2.0210 X-Barracuda-Spam-Score: -2.02 X-Barracuda-Spam-Status: No, SCORE=-2.02 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 3.2.2.72191 Rule breakdown below pts rule name description ---- ---------------------- -------------------------------------------------- Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2011-08-16 04:47, Shaohua Li wrote: > We have a kernel build regression since 3.1-rc1, which is about 10% > regression. The kernel source is in an ext3 filesystem. > Alex Shi bisect it to commit: > commit a07405b7802691d29ab3b23bdc76ee6d006aad0b > Author: Justin TerAvest > Date: Sun Jul 10 22:09:19 2011 +0200 > > cfq: Remove special treatment for metadata rqs. > > Apparently this is caused by lack metadata preemption, where ext3/ext4 > do use READ_META. I didn't see a way to fix the issue, so suggest > reverting the patch. > > Reported-by: Alex Shi > Reported-by: Shaohua Li I had a gut feeling on that meta data, it's hard to know exactly where it helps at this point. I'll revert the commit and then we can diagnose this on the side. -- Jens Axboe