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=-8.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 3D8EBC433E1 for ; Sat, 18 Jul 2020 20:22:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1F64F2073E for ; Sat, 18 Jul 2020 20:22:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726837AbgGRUWb (ORCPT ); Sat, 18 Jul 2020 16:22:31 -0400 Received: from mail-pg1-f193.google.com ([209.85.215.193]:44084 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726801AbgGRUWb (ORCPT ); Sat, 18 Jul 2020 16:22:31 -0400 Received: by mail-pg1-f193.google.com with SMTP id j19so8330209pgm.11; Sat, 18 Jul 2020 13:22:30 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=WgiU3sE9W5l55r+mqCm7ZyiWtQixr0nXZ9gsgnHQhWY=; b=cWek8xpAN7az/pQNCoOjyfHdi0wwoPcd1JR4OjPKRhWzhNhk/JBbX9PrF0OV1WWr1W zvKmub/BRtRjJ8Rpe3qmhkXN4xU6zkuFc/aRiY9Nt2H+TvBByF/vdQ6OMKnZpSatHGWD FTW2V2A772QwtQBE68T3MWaTWAg3J2R8TZYljitVkILcf+TiqbXXW/fRzXhJf6TZ3hQC D/HNhQPnuSvOsQw6npcU6v1KmWekBerSXdg7iaKUYCzpYRE1cGydFGhR7Min2F89DuLT F86nEy7QWUtErfcegr/C8i795kvnlm/XBIM5zcueDrGymMNbJKbCSjA4Zlr6Y4dup1HD bXXw== X-Gm-Message-State: AOAM531xpcaLRZIyI0p7OLzvG7oImdlaaq94Ofbk1l22KdpEb+juVYRj CtTd1QdpUDvOurXU/u/Ly6M= X-Google-Smtp-Source: ABdhPJyur9FOx7tbAKc1TU72nd7zqKdBOZYn762UQkuR8YcXcDRpnd/Hx3oLDnFNNpWlRnm3lAf/dg== X-Received: by 2002:a63:b18:: with SMTP id 24mr14130324pgl.406.1595103750250; Sat, 18 Jul 2020 13:22:30 -0700 (PDT) Received: from [192.168.50.147] (c-73-241-217-19.hsd1.ca.comcast.net. [73.241.217.19]) by smtp.gmail.com with ESMTPSA id a33sm10854379pgl.75.2020.07.18.13.22.28 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 18 Jul 2020 13:22:28 -0700 (PDT) Subject: Re: [PATCH] scsi: core: run queue in case of IO queueing failure To: Ming Lei , James Bottomley , linux-scsi@vger.kernel.org, "Martin K . Petersen" Cc: linux-block@vger.kernel.org, Christoph Hellwig References: <20200708131405.3346107-1-ming.lei@redhat.com> From: Bart Van Assche Autocrypt: addr=bvanassche@acm.org; prefer-encrypt=mutual; keydata= mQENBFSOu4oBCADcRWxVUvkkvRmmwTwIjIJvZOu6wNm+dz5AF4z0FHW2KNZL3oheO3P8UZWr LQOrCfRcK8e/sIs2Y2D3Lg/SL7qqbMehGEYcJptu6mKkywBfoYbtBkVoJ/jQsi2H0vBiiCOy fmxMHIPcYxaJdXxrOG2UO4B60Y/BzE6OrPDT44w4cZA9DH5xialliWU447Bts8TJNa3lZKS1 AvW1ZklbvJfAJJAwzDih35LxU2fcWbmhPa7EO2DCv/LM1B10GBB/oQB5kvlq4aA2PSIWkqz4 3SI5kCPSsygD6wKnbRsvNn2mIACva6VHdm62A7xel5dJRfpQjXj2snd1F/YNoNc66UUTABEB AAG0JEJhcnQgVmFuIEFzc2NoZSA8YnZhbmFzc2NoZUBhY20ub3JnPokBOQQTAQIAIwUCVI67 igIbAwcLCQgHAwIBBhUIAgkKCwQWAgMBAh4BAheAAAoJEHFcPTXFzhAJ8QkH/1AdXblKL65M Y1Zk1bYKnkAb4a98LxCPm/pJBilvci6boefwlBDZ2NZuuYWYgyrehMB5H+q+Kq4P0IBbTqTa jTPAANn62A6jwJ0FnCn6YaM9TZQjM1F7LoDX3v+oAkaoXuq0dQ4hnxQNu792bi6QyVdZUvKc macVFVgfK9n04mL7RzjO3f+X4midKt/s+G+IPr4DGlrq+WH27eDbpUR3aYRk8EgbgGKvQFdD CEBFJi+5ZKOArmJVBSk21RHDpqyz6Vit3rjep7c1SN8s7NhVi9cjkKmMDM7KYhXkWc10lKx2 RTkFI30rkDm4U+JpdAd2+tP3tjGf9AyGGinpzE2XY1K5AQ0EVI67igEIAKiSyd0nECrgz+H5 PcFDGYQpGDMTl8MOPCKw/F3diXPuj2eql4xSbAdbUCJzk2ETif5s3twT2ER8cUTEVOaCEUY3 eOiaFgQ+nGLx4BXqqGewikPJCe+UBjFnH1m2/IFn4T9jPZkV8xlkKmDUqMK5EV9n3eQLkn5g lco+FepTtmbkSCCjd91EfThVbNYpVQ5ZjdBCXN66CKyJDMJ85HVr5rmXG/nqriTh6cv1l1Js T7AFvvPjUPknS6d+BETMhTkbGzoyS+sywEsQAgA+BMCxBH4LvUmHYhpS+W6CiZ3ZMxjO8Hgc ++w1mLeRUvda3i4/U8wDT3SWuHcB3DWlcppECLkAEQEAAYkBHwQYAQIACQUCVI67igIbDAAK CRBxXD01xc4QCZ4dB/0QrnEasxjM0PGeXK5hcZMT9Eo998alUfn5XU0RQDYdwp6/kMEXMdmT oH0F0xB3SQ8WVSXA9rrc4EBvZruWQ+5/zjVrhhfUAx12CzL4oQ9Ro2k45daYaonKTANYG22y //x8dLe2Fv1By4SKGhmzwH87uXxbTJAUxiWIi1np0z3/RDnoVyfmfbbL1DY7zf2hYXLLzsJR mSsED/1nlJ9Oq5fALdNEPgDyPUerqHxcmIub+pF0AzJoYHK5punqpqfGmqPbjxrJLPJfHVKy goMj5DlBMoYqEgpbwdUYkH6QdizJJCur4icy8GUNbisFYABeoJ91pnD4IGei3MTdvINSZI5e Message-ID: Date: Sat, 18 Jul 2020 13:22:27 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200708131405.3346107-1-ming.lei@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 2020-07-08 06:14, Ming Lei wrote: > diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > index 534b85e87c80..4d7fab9e8af9 100644 > --- a/drivers/scsi/scsi_lib.c > +++ b/drivers/scsi/scsi_lib.c > @@ -1694,6 +1694,16 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx, > */ > if (req->rq_flags & RQF_DONTPREP) > scsi_mq_uninit_cmd(cmd); > + > + /* > + * Requests may be held in block layer queue because of > + * resource contention. We usually run queue in normal > + * completion for queuing these requests again. Block layer > + * will finish this failed request simply, run queue in case > + * of IO queueing failure so that requests can get chance to > + * be finished. > + */ > + scsi_run_queue(q); > break; > } > return ret; So this patch causes blk_mq_run_hw_queues() to be called synchronously from inside blk_mq_run_hw_queues()? Wouldn't it be better to avoid such recursion and to run the queue asynchronously instead of synchronously from inside scsi_queue_rq()? The following code already exists in scsi_end_request(): blk_mq_run_hw_queues(q, true); Thanks, Bart.