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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EDD26C74A5B for ; Wed, 29 Mar 2023 03:17:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229976AbjC2DR1 (ORCPT ); Tue, 28 Mar 2023 23:17:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52624 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229451AbjC2DRX (ORCPT ); Tue, 28 Mar 2023 23:17:23 -0400 Received: from mail-pj1-f42.google.com (mail-pj1-f42.google.com [209.85.216.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 99DE81FDA; Tue, 28 Mar 2023 20:17:22 -0700 (PDT) Received: by mail-pj1-f42.google.com with SMTP id p3-20020a17090a74c300b0023f69bc7a68so14752946pjl.4; Tue, 28 Mar 2023 20:17:22 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680059842; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=uLjUKExRZYqRLUfr3tzAXkQagcsDKdjQLlBbO0Cmu08=; b=QS5p4YmlT/rPPgG4wdhKjv4+pu9pEDL//gOii7klYgTeB53St+CJCX0u4w6JtjZVF5 mPHFbnqiR+R0DTPiRHSsuNTgFzGQYwMF0Y4uU2l4sna48RkbpHOfOmPwSxHZGPZGSJ/K B0rwnJw55tsRql+mBau1ulF803fhDp4NWiBEi7jNGNHjMy9e3grbz7JAX05kkHPoN45r o5ZGkyREAvZ0utKDxqEF0koztggfsisKc3d6KNFlWikqmZUASfrT1O9G+m+hUESj5gIq yjW9U6EWUJppSdhMlh1qgjF3K/OgKwRW9nxiaqnFoqyduaitlaEQVsrk78Ywlqv4F2vo eOLA== X-Gm-Message-State: AAQBX9cZ/6H1gR7F9uHAASjDAAFZO17f0VkEKu/OIL+/0KqfkzJTbJHj 4XHqtNXESz2jPEDRyNX6SvmnvCxynIQ= X-Google-Smtp-Source: AKy350YzVZu7jRaQqedo3XXu6FnU0XGFplGppJjGk6e5le4T7qcgACa5GO7OfY6ejksf9kF5QL3ZAQ== X-Received: by 2002:a17:903:3092:b0:19e:786f:4cac with SMTP id u18-20020a170903309200b0019e786f4cacmr14079031plc.53.1680059841938; Tue, 28 Mar 2023 20:17:21 -0700 (PDT) Received: from [192.168.3.219] ([98.51.102.78]) by smtp.gmail.com with ESMTPSA id ji17-20020a170903325100b00199023c688esm21853735plb.26.2023.03.28.20.17.19 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 28 Mar 2023 20:17:21 -0700 (PDT) Message-ID: <9266aa1b-2d63-43d5-f06e-5a228bc131be@acm.org> Date: Tue, 28 Mar 2023 20:17:19 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.9.0 Subject: Re: [PATCH] scsi: ufs: core: Make UFS_MCQ_NUM_DEV_CMD_QUEUES a module parameter Content-Language: en-US To: Po-Wen Kao , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, Alim Akhtar , Avri Altman , "James E.J. Bottomley" , "Martin K. Petersen" , Matthias Brugger , AngeloGioacchino Del Regno Cc: wsd_upstream@mediatek.com, peter.wang@mediatek.com, stanley.chu@mediatek.com, alice.chao@mediatek.com, naomi.chu@mediatek.com, chun-hung.wu@mediatek.com, cc.chou@mediatek.com, eddie.huang@mediatek.com, mason.zhang@mediatek.com, chaotian.jing@mediatek.com, jiajie.hao@mediatek.com References: <20230328103000.10757-1-powen.kao@mediatek.com> From: Bart Van Assche In-Reply-To: <20230328103000.10757-1-powen.kao@mediatek.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/28/23 03:29, Po-Wen Kao wrote: > A dedicated queue for dev commands is not mandatory, hence let > UFS_MCQ_NUM_DEV_CMD_QUEUES become module parameter `dev_cmd_queues` > to allow sharing first hw queue for dev commands. Which queue is selected for device management commands? What is the impact of this change? If a device command is queued on a queue with multiple pending commands, does that mean that it can take long for the device command to reach the UFS device? The answer to the above questions should be in the patch description. Please expand the patch description. > +unsigned int dev_cmd_queues = 1; > +module_param_cb(dev_cmd_queues, &dev_cmd_queue_count_ops, &dev_cmd_queues, 0644); > +MODULE_PARM_DESC(dev_cmd_queues, > + "Number of queues used for dev command. Default value is 1"); I prefer a solution that does not require any new kernel module parameters. That means either a dedicated device command queue for all host controllers or no dedicated device command queue for any host controller. Thanks, Bart.