From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B1B0FC3A5A9 for ; Mon, 4 May 2020 09:08:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 97F99206D9 for ; Mon, 4 May 2020 09:08:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727125AbgEDJIb (ORCPT ); Mon, 4 May 2020 05:08:31 -0400 Received: from lhrrgout.huawei.com ([185.176.76.210]:2150 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726625AbgEDJIb (ORCPT ); Mon, 4 May 2020 05:08:31 -0400 Received: from lhreml724-chm.china.huawei.com (unknown [172.18.7.107]) by Forcepoint Email with ESMTP id B971EE4C47A9C6E82259; Mon, 4 May 2020 10:08:29 +0100 (IST) Received: from [127.0.0.1] (10.210.171.25) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1913.5; Mon, 4 May 2020 10:08:29 +0100 Subject: Re: [PATCH V9 00/11] blk-mq: improvement CPU hotplug To: Ming Lei CC: Jens Axboe , , Bart Van Assche , Hannes Reinecke , Christoph Hellwig , Thomas Gleixner References: <20200502235454.1118520-1-ming.lei@redhat.com> <5db8635b-b606-3dd9-ce1d-5280097acbd3@huawei.com> <20200504083831.GA1139563@T590> From: John Garry Message-ID: <4892e8d0-0a4b-2f35-130c-eae23d578549@huawei.com> Date: Mon, 4 May 2020 10:07:45 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 In-Reply-To: <20200504083831.GA1139563@T590> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.210.171.25] X-ClientProxiedBy: lhreml712-chm.china.huawei.com (10.201.108.63) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 04/05/2020 09:38, Ming Lei wrote: >> [67.602937] refcount_warn_saturate+0x6c/0x13c >> [67.607369] aio_complete_rw+0x350/0x384 >> [67.611279] blkdev_bio_end_io+0xc4/0x12c >> [67.615276] bio_endio+0x104/0x130 >> [67.618665] blk_update_request+0x98/0x37c >> [67.622748] blk_mq_end_request+0x24/0x138 >> [67.626831] blk_mq_resubmit_end_rq+0x40/0x58 >> [67.631174] __blk_mq_end_request+0xb0/0x10c >> [67.635432] scsi_end_request+0xdc/0x20c > Looks an old issue, I believe the following patch can fix the issue: > > diff --git a/block/blk-mq.c b/block/blk-mq.c > index 12dee4ecd5cc..3fc79d4b2fe0 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -2415,6 +2415,10 @@ static void blk_mq_resubmit_rq(struct request *rq) > nrq->bio = rq->bio; > nrq->biotail = rq->biotail; > > + /* Now all bios ownership is transfered to 'nrq' */ > + rq->bio = rq->biotail = NULL; > + rq->__data_len = 0; > + > if (blk_insert_cloned_request(nrq->q, nrq) != BLK_STS_OK) > blk_mq_request_bypass_insert(nrq, false, true); > } ok, looks much better. I'll test this a bit more now. cheers