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=-7.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 C6EDAC433E2 for ; Thu, 3 Sep 2020 11:41:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8B20E20709 for ; Thu, 3 Sep 2020 11:41:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="dpnMey+j" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728642AbgICLlF (ORCPT ); Thu, 3 Sep 2020 07:41:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38074 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728695AbgICLkd (ORCPT ); Thu, 3 Sep 2020 07:40:33 -0400 Received: from mail-pg1-x544.google.com (mail-pg1-x544.google.com [IPv6:2607:f8b0:4864:20::544]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 22FA8C061244 for ; Thu, 3 Sep 2020 04:40:33 -0700 (PDT) Received: by mail-pg1-x544.google.com with SMTP id u13so1932382pgh.1 for ; Thu, 03 Sep 2020 04:40:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=BbEzMsXeJFMaOZkE8yoL1Se14OvSsVtVf2jVI5mEwnQ=; b=dpnMey+jlMM0j/gJQ9QAiDjtIYrat8OUFvlc7L+FKZ++IPczlrPxzXYPACdMPWqVLr 14NStW4AIZuRWw4tzCJ267i/7NLt7KjpxBnheTM+KBpzAf68rzBKI62764daDf0YFSJ7 1ga2gqBOTbwNIQ7LxmeLSBR/PRQGYVYRURg2QzPaObAV/V32LJe0+IBAvrxTJQDLYTp8 ySWoqA1eKZ1qzRepgyQy1kusDpgoQtxPAtXaSZ9HoDHgOdx2du95FQFIoKvw4MfTZ/rs 7P917C7O34SqumVUSZlUoOfjmLK3niYTG7vpIpCuf9eJQDo836iF0K0nrl8aO70TCGOY AOUA== 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:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=BbEzMsXeJFMaOZkE8yoL1Se14OvSsVtVf2jVI5mEwnQ=; b=uY5GOXBnSE3Kyj4NcfAdtCpdLJrN9tsFRHG5glyvdCzIf1y9xY5MhcVIkZSETxvJ+b Xf06cmofqbXTSbWd+2vl8Y5zhRck6FKAEClwBAQ+0D8FBDtEvgrppr/nLumuXe3OJiR0 NnPzw9iJOeBXpyqZIU0Ux/WikjaiGmGAZFYO6YgY0m2KnSZ5NC2SXXDxgAjZP0N4Z7mn eaUFEVtKNVLhQmy05LWDCGjq/fd0U4eC8ORcC/2EFCm5EjfCoHJ4M7Xv+o/azdzTBXiw RVQguqtWmvzf24r6rm6MZZ+gNHHURK3+GQSe1ZuGFoXbEoO9TWtMcSbIVvleWt7CY25d 8lhA== X-Gm-Message-State: AOAM533AvN/IWgHpCYyfyQNdPrSTjkvrGDnqeW/IXFluxuLH/yn/sUTV W48H+8ybkaI4Kn6Ey8NS8/Wmz3sTYOsZoUBJ X-Google-Smtp-Source: ABdhPJxh2F4UwSxA1zfApE3Z4knIzbl0WGRoNeUyajFRr3H03XMOuK0xNCEQIOS1I89yP7vLFYvNlg== X-Received: by 2002:a17:902:788e:: with SMTP id q14mr3484123pll.140.1599133232465; Thu, 03 Sep 2020 04:40:32 -0700 (PDT) Received: from [192.168.1.187] ([66.219.217.173]) by smtp.gmail.com with ESMTPSA id mp1sm2453694pjb.27.2020.09.03.04.40.31 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 03 Sep 2020 04:40:31 -0700 (PDT) Subject: Re: [PATCH] io_uring: don't hold fixed_file_data's lock when registering files To: Xiaoguang Wang , io-uring@vger.kernel.org Cc: joseph.qi@linux.alibaba.com References: <20200902113256.6620-1-xiaoguang.wang@linux.alibaba.com> From: Jens Axboe Message-ID: <1b698dd1-3440-3fcc-bc4f-3e9e48b029e2@kernel.dk> Date: Thu, 3 Sep 2020 05:40:30 -0600 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: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 9/2/20 10:35 PM, Xiaoguang Wang wrote: > hi， > >> On 9/2/20 5:32 AM, Xiaoguang Wang wrote: >>> While registering new files by IORING_REGISTER_FILES, there're not >>> valid fixed_file_ref_node at the moment, so it's unnecessary to hold >>> fixed_file_data's lock when registering files. >> >> Even if that were the case (I haven't looked too closely at it yet), >> it would a) need a big comment explaining why, and b) some justification >> on why this would be a change we'd want to make. >> >> On b, are you seeing any tangible differences with this? > No, just found this by reading source codes. OK, then I suggest we leave it as it is. The data race analyzers wouldn't be very happy with it either. -- Jens Axboe