Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756887AbaGDPf0 (ORCPT ); Fri, 4 Jul 2014 11:35:26 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:30866 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752129AbaGDPfZ (ORCPT ); Fri, 4 Jul 2014 11:35:25 -0400 Message-ID: <53B6C9BA.1020106@fb.com> Date: Fri, 4 Jul 2014 09:35:22 -0600 From: Jens Axboe User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Shaohua Li , Subject: Re: [patch]blk-mq: suppress a warning References: <20140704112623.GA17435@kernel.org> In-Reply-To: <20140704112623.GA17435@kernel.org> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [192.168.57.29] X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.12.52,1.0.14,0.0.0000 definitions=2014-07-04_05:2014-07-04,2014-07-04,1970-01-01 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 kscore.is_bulkscore=7.61524268089175e-08 kscore.compositescore=0 circleOfTrustscore=502.112 compositescore=0.9989857498195 urlsuspect_oldscore=0.9989857498195 suspectscore=0 recipient_domain_to_sender_totalscore=0 phishscore=0 bulkscore=0 kscore.is_spamscore=0 recipient_to_sender_totalscore=0 recipient_domain_to_sender_domain_totalscore=62764 rbsscore=0.9989857498195 spamscore=0 recipient_to_sender_domain_totalscore=0 urlsuspectscore=0.9 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=7.0.1-1402240000 definitions=main-1407040177 X-FB-Internal: deliver Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/04/2014 05:26 AM, Shaohua Li wrote: > > The warning is hit when cpu hotplug is running. After scheduler puts a cpu > online and before blk-mq mapping reinit, a task can queue a request and run the > queue. At that time the cpu isn't in hctx->cpumask, but the cpu is mapped into > hctx 0. When the race happens, hctx->cpumask doesn't set the cpu and > ctx->index_hw/hctx->nr_ctx isn't correct, but it doesn't cause any problem. So > just suppress the warning here. Thanks Shaohua, I think that is an improvement. Not super fond of having to do an extra map, but it's saner than the CPU test in that it uses the same mechanism to verify it's correct. And we can probably kill this WARN_ON() in a revision or two. -- 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/