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 B07A3C3A5A9 for ; Mon, 4 May 2020 09:58:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 86E202071C for ; Mon, 4 May 2020 09:58:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728401AbgEDJ6G (ORCPT ); Mon, 4 May 2020 05:58:06 -0400 Received: from lhrrgout.huawei.com ([185.176.76.210]:2155 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728079AbgEDJ6F (ORCPT ); Mon, 4 May 2020 05:58:05 -0400 Received: from lhreml724-chm.china.huawei.com (unknown [172.18.7.107]) by Forcepoint Email with ESMTP id 4DFA7D4BA2B49E0EB57B; Mon, 4 May 2020 10:58:04 +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 10:58:03 +0100 Subject: Re: [PATCH V9 00/11] blk-mq: improvement CPU hotplug From: John Garry 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> <4892e8d0-0a4b-2f35-130c-eae23d578549@huawei.com> Message-ID: <6e4c4382-c52b-14ac-8538-71e683dce47e@huawei.com> Date: Mon, 4 May 2020 10:57:19 +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: <4892e8d0-0a4b-2f35-130c-eae23d578549@huawei.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit 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 10:07, John Garry wrote: > 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. looks pretty solid now. I assume we'll see a v10, so please add: Tested-by: John Garry > > cheers > > .