Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752889AbaFDPIU (ORCPT ); Wed, 4 Jun 2014 11:08:20 -0400 Received: from mail-pb0-f41.google.com ([209.85.160.41]:52793 "EHLO mail-pb0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752198AbaFDPIP (ORCPT ); Wed, 4 Jun 2014 11:08:15 -0400 Message-ID: <538F365C.8050604@kernel.dk> Date: Wed, 04 Jun 2014 09:08:12 -0600 From: Jens Axboe User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: Christoph Hellwig CC: Shaohua Li , linux-kernel@vger.kernel.org Subject: Re: [patch]blk-mq: blk_mq_tag_to_rq should handle flush request References: <20140509120733.GA27918@kernel.org> <20140509150018.GA26215@infradead.org> <20140510040023.GA13788@kernel.org> <5388912F.7010609@kernel.dk> <20140604111133.GA7826@infradead.org> <538F2A11.4060800@kernel.dk> <20140604142012.GA20056@infradead.org> <538F331F.60101@kernel.dk> <20140604145803.GA7826@infradead.org> <538F34FB.7050003@kernel.dk> <20140604150508.GA21551@infradead.org> In-Reply-To: <20140604150508.GA21551@infradead.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2014-06-04 09:05, Christoph Hellwig wrote: > On Wed, Jun 04, 2014 at 09:02:19AM -0600, Jens Axboe wrote: >> OK strange, there hasn't been that much churn since the last rebase. >> In my for-linus, there's a patch for a single queue crash, but that >> should just hit for the removal case. And then there's the atomic >> schedule patch, but that issue was actually in the code base for >> about a month, so not a new one either. > > You're request initializaion optimization doesn't set up req->cmd and > thus causes all BLOCK_PC I/O (including the SCSI LUN scan) to crash and > burn. The trivial fix is on your way. OK. That'll arguably be a good cleanup as well, getting that initialized in the right place. I hate the 'lets clear all the memory' part of rq init, it's not super cheap to do. > The performance regression is caused by "blk-mq: avoid code > duplication", but I don't really understand why yet. Gah, looks like this one dropped the tag idling. I bet that is why. -- 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/