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 8C083C7EE43 for ; Wed, 1 Feb 2023 17:34:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231707AbjBARe0 (ORCPT ); Wed, 1 Feb 2023 12:34:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57712 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232127AbjBAReS (ORCPT ); Wed, 1 Feb 2023 12:34:18 -0500 Received: from mail-pj1-f41.google.com (mail-pj1-f41.google.com [209.85.216.41]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 049E168AEC; Wed, 1 Feb 2023 09:33:51 -0800 (PST) Received: by mail-pj1-f41.google.com with SMTP id l4-20020a17090a850400b0023013402671so2930231pjn.5; Wed, 01 Feb 2023 09:33:50 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; 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=q/aU7Sx+Q2q+ijznzRLc/zl8vln97T87YSV2SvjpCmw=; b=NoLXqe8+25lyX9nERFHTPag0M6UHjxIp4pH9S6XXo4J/pLBSPPoXYdZ1tlZvvxHZ7l qaMqpUDbWB2cxw2FdJV0y0kMpsCKgWQ7BQ6F1Umhvk5HkQdDT25K2zGWl+haHBk3H8zO /t38FsEYCbbG22gLfXFtuWBX8WXgsVONrLHmwayiAqS0Z+fP69xpLRxnKm/vRccOBrVI PsUofoIJ5qICtoxPEKxrxEqGlR4UTIBaZ+3mkOc3Cdn0lGpIgbzl9h6v6zxOzfuCrWH4 WKtTEqDvzxAX+mOGAmA9mBsSA6B4hTeRTH7OfkyBN9sVt0ikhF4NJ9CNvTo+iSQDLFng c8Qw== X-Gm-Message-State: AO0yUKVbTOnIDxAkx4AIIP2os1ja6HCjbqTOH3NmRFxAybxPMRCCH2gL v0zvIQKTlRPPj3rN/6iTSblHycF9LKQ= X-Google-Smtp-Source: AK7set9Ycqux29N2wsB31xcfCQChDuOZNpbLrXNTTh/WzZIVKAYDMFTzZ4Xw5aYXc54sZ606NodI2Q== X-Received: by 2002:a17:903:cd:b0:195:f097:d65b with SMTP id x13-20020a17090300cd00b00195f097d65bmr12801187plc.49.1675272807088; Wed, 01 Feb 2023 09:33:27 -0800 (PST) Received: from ?IPV6:2620:15c:211:201:f3cf:17ca:687:af15? ([2620:15c:211:201:f3cf:17ca:687:af15]) by smtp.gmail.com with ESMTPSA id p1-20020a1709026b8100b00192b23b8451sm12005700plk.108.2023.02.01.09.33.25 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 01 Feb 2023 09:33:26 -0800 (PST) Message-ID: <8c068af3-7199-11cf-5c69-a523c7c22d9a@acm.org> Date: Wed, 1 Feb 2023 09:33:24 -0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.6.0 Subject: Re: [PATCH] blk-ioprio: Introduce promote-to-rt policy Content-Language: en-US To: Hou Tao , linux-block@vger.kernel.org Cc: Jan Kara , Jens Axboe , cgroups@vger.kernel.org, Tejun Heo , Zefan Li , Johannes Weiner , Jonathan Corbet , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, houtao1@huawei.com References: <20230201045227.2203123-1-houtao@huaweicloud.com> From: Bart Van Assche In-Reply-To: <20230201045227.2203123-1-houtao@huaweicloud.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 1/31/23 20:52, Hou Tao wrote: > /** > * enum prio_policy - I/O priority class policy. > * @POLICY_NO_CHANGE: (default) do not modify the I/O priority class. > @@ -27,21 +34,30 @@ > * @POLICY_RESTRICT_TO_BE: modify IOPRIO_CLASS_NONE and IOPRIO_CLASS_RT into > * IOPRIO_CLASS_BE. > * @POLICY_ALL_TO_IDLE: change the I/O priority class into IOPRIO_CLASS_IDLE. > - * > + * @POLICY_PROMOTE_TO_RT: modify IOPRIO_CLASS_NONE and IOPRIO_CLASS_BE into > + * IOPRIO_CLASS_RT. > * See also . > */ > enum prio_policy { > - POLICY_NO_CHANGE = 0, > - POLICY_NONE_TO_RT = 1, > - POLICY_RESTRICT_TO_BE = 2, > - POLICY_ALL_TO_IDLE = 3, > + POLICY_NO_CHANGE = IOPRIO_CLASS_NONE, > + POLICY_NONE_TO_RT = IOPRIO_CLASS_RT, > + POLICY_RESTRICT_TO_BE = IOPRIO_CLASS_BE, > + POLICY_ALL_TO_IDLE = IOPRIO_CLASS_IDLE, > + POLICY_PROMOTE_TO_RT = IOPRIO_CLASS_RT | IOPRIO_POL_PROMOTION, > +}; The above change complicates the ioprio code. Additionally, I'm concerned that it makes the ioprio code slower. Has it been considered to keep the numerical values for the existing policies, to assign the number 4 to POLICY_PROMOTE_TO_RT and to use a lookup-array in blkcg_set_ioprio() to convert the policy number into an IOPRIO_CLASS value? Thanks, Bart.