From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932209AbaISRwq (ORCPT ); Fri, 19 Sep 2014 13:52:46 -0400 Received: from mail-pd0-f177.google.com ([209.85.192.177]:54951 "EHLO mail-pd0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932069AbaISRwp (ORCPT ); Fri, 19 Sep 2014 13:52:45 -0400 Message-ID: <541C6D7B.5000005@kernel.dk> Date: Fri, 19 Sep 2014 11:52:59 -0600 From: Jens Axboe User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.1.1 MIME-Version: 1.0 To: Christoph Hellwig , Ming Lei CC: linux-kernel@vger.kernel.org Subject: Re: [PATCH] blk-mq: auto-start hw queue in requeue References: <1411136570-23439-1-git-send-email-ming.lei@canonical.com> <20140919174806.GA19983@lst.de> In-Reply-To: <20140919174806.GA19983@lst.de> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/19/2014 11:48 AM, Christoph Hellwig wrote: > On Fri, Sep 19, 2014 at 10:22:50PM +0800, Ming Lei wrote: >> Requests often need to be retried because of timeout, hardware >> busy or sort of reasons via blk_mq_requeue_request(), but at >> that time dispatch queue may have been stopped. >> >> This patch starts the dispatch queue automatically in requeue's >> work handler, and fixes scsi-mq's timeout issue, which can be >> triggered if there are two or more requests timedout. > > Sounds like blk_mq_requeue_work should simply call void > blk_mq_start_hw_queues where it calls blk_mq_run_queues currently. I agree. I think Ming wanted to avoid an unnecessary bitflip if possible, but the fix is more convoluted than I would like. -- Jens Axboe