Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756350Ab2BHI34 (ORCPT ); Wed, 8 Feb 2012 03:29:56 -0500 Received: from mail-qy0-f174.google.com ([209.85.216.174]:61927 "EHLO mail-qy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755461Ab2BHI3y convert rfc822-to-8bit (ORCPT ); Wed, 8 Feb 2012 03:29:54 -0500 MIME-Version: 1.0 In-Reply-To: References: <20120206163721.GF30752@redhat.com> <20120206164428.GA21292@google.com> <20120206172706.GB21292@google.com> <4F303506.9000201@kernel.dk> <20120206215451.GD21292@google.com> <4F30C96F.1000905@kernel.dk> <20120207162253.GG21292@google.com> <4F315113.5010804@kernel.dk> <20120207164735.GH21292@google.com> Date: Wed, 8 Feb 2012 16:29:53 +0800 X-Google-Sender-Auth: JdrrJks8NJZzChyosYDHAokfRlo Message-ID: Subject: Re: [PATCH] block: strip out locking optimization in put_io_context() From: Shaohua Li To: Tejun Heo Cc: Linus Torvalds , Jens Axboe , Vivek Goyal , lkml , Knut Petersen , mroos@linux.ee Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1446 Lines: 35 2012/2/8 Shaohua Li : > 2012/2/8 Tejun Heo : >> Hello, >> >> On Tue, Feb 07, 2012 at 08:33:15AM -0800, Linus Torvalds wrote: >>> Yeah, please just get rid of the crazy code. Maybe *that* fixes the >>> regression too, who knows? >>> >>> For all we know, the "fast case" is what causes extra locking only to >>> then fail and not even be a fast-path. >> >> Yeah, I was about to ask Shaohua to test the version w/o optimization. >> With heavily loaded request_queue, trylock failure could be frequent, >> which I wasn't testing. >> >> Shaohua, can you please test the version w/o optimization? ?Also, can >> you please give a bit more details on the setup? ?Are there multiple >> swap devices? ?Is it SSD or rotating disk? > the test adds mem=4G in a 2 sockets 16 CPU machine. > just make several copy of kernel source in tmpfs (so there is swap > depending on your > memory size) and run kernel build in the kernel source in the meaning time. > there is only one swap device which is a rotating disk. > > I'll test both patches soon. Tried all the options, the regression still exists. Any new idea? I'll spend some time on it if I can get anything Thanks, Shaohua -- 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/