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 BFD06C4332F for ; Fri, 25 Feb 2022 02:11:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235070AbiBYCMH (ORCPT ); Thu, 24 Feb 2022 21:12:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37012 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235994AbiBYCME (ORCPT ); Thu, 24 Feb 2022 21:12:04 -0500 Received: from mail-pf1-x431.google.com (mail-pf1-x431.google.com [IPv6:2607:f8b0:4864:20::431]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E9A967658; Thu, 24 Feb 2022 18:11:32 -0800 (PST) Received: by mail-pf1-x431.google.com with SMTP id d17so3504244pfl.0; Thu, 24 Feb 2022 18:11:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :cc:references:from:in-reply-to:content-transfer-encoding; bh=cMIbfsx8xhlhlO0rypyks70MaXjDJamppwKLSs70zXg=; b=agWfV/KneIzXmyRrz9MpUkEGgtLQ5KieS3r1T3hSsxxTTjGHJaicT4V4kxEGKONjVE Wh9CgIJBTHvaGQ1v7gf9NEIe9gZYcqGNOsHaaSCmxYOJIXCNOGxp76w8CbxJqcO6T134 qAVaYVuyz3CVRipALOty+jj9f8rTzFIDx+uHOUmgywNiXZHQ2sHCgRoQUqWF2p85L3iO xHLYhKcDdQA4d+4B3ipOQwbYvkLjSoAuNv8FHbi7MVmnTNSKXZ+CZUUcknxIhTwIVsgb UrlgGSHZX4lw8ZUUmbJ0ZtgJbtse6r5WLZC+Fr83Uo2Us7l75FA76Pzc3QyxQPHsZn8R nvxQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=cMIbfsx8xhlhlO0rypyks70MaXjDJamppwKLSs70zXg=; b=fkSd/cs//mDToW2GtMB/HWyU3Icz0omhULs9lDCHVdk0f6F0w73AQFmlG2tJ8nPWCZ DNjqTYq55GPNWj0JLZZg5K6lkdcVRbZNWaBb0kNZfNwJQblIYmzdlQ/4YqnXvoKF46Yg zCqHU4wB8j+ReLAdguqX+AYXIzLDfaYlJstIVwRYGcygUX88HF4Y1RRvucy5qTknpXHM 6stlTqhF8BeWkNDCvnqB1BczgIivJFxiNzCpi887+mtgO69xxpue+MLRFCVdlcMm1tXW xHG/TS3+2y/fB2i88f7ShhWRnqjr+cMEmmodXVpqVXK0ZJMH8NO+Mvq69Nf+9Ma/1vch Fv2A== X-Gm-Message-State: AOAM530V9O/MyT4toVQ0HercQsfocZSGV0ATiAsDx5Jn9G1RfnLgj//V zfahBpVAgPA8wLDMdgFEIcP41QALa71Mdg== X-Google-Smtp-Source: ABdhPJxFcvdnn/j15+geNn7yyDWNYYaTArNomqCKM6Cn4Z8bJTS3viCvPilmLH4a3DbEyOErUhCO7g== X-Received: by 2002:a63:d201:0:b0:372:c882:210f with SMTP id a1-20020a63d201000000b00372c882210fmr4418862pgg.198.1645755092437; Thu, 24 Feb 2022 18:11:32 -0800 (PST) Received: from [172.20.119.15] ([162.219.34.248]) by smtp.gmail.com with ESMTPSA id f4-20020a63f744000000b00373855b7cf2sm745316pgk.22.2022.02.24.18.11.30 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 24 Feb 2022 18:11:32 -0800 (PST) Message-ID: <99ff40cc-8e56-3dff-ccc5-095844734818@gmail.com> Date: Fri, 25 Feb 2022 10:11:29 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.6.1 Subject: Re: [RFC V5 01/16] blk: make the whole blk_mq_submit_bio under q_usage_counter Content-Language: en-US To: Christoph Hellwig Cc: Jens Axboe , Josef Bacik , Tejun Heo , Bart Van Assche , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org References: <20220224090654.54671-1-jianchao.wan9@gmail.com> <20220224090654.54671-2-jianchao.wan9@gmail.com> From: Wang Jianchao In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/2/24 9:38 下午, Christoph Hellwig wrote: > On Thu, Feb 24, 2022 at 05:06:39PM +0800, Wang Jianchao (Kuaishou) wrote: >> This is to protect the rqos list against the rqos open/close. We >> need to drain all of the caller of blk_mq_submit_bio() before >> we can operate the rqos list. > > This means ever I/O now has to d an extra refcount roundtrip. If we want to save cpu cycles for the very fast device, why not introduce another blk_mq_submit_bio_fast() which can reduce the code drastically. Thanks Jianchao