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=-5.3 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 A6F3FC11F65 for ; Wed, 30 Jun 2021 21:17:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 83F1F613E0 for ; Wed, 30 Jun 2021 21:17:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233754AbhF3VUK (ORCPT ); Wed, 30 Jun 2021 17:20:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32996 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229774AbhF3VUJ (ORCPT ); Wed, 30 Jun 2021 17:20:09 -0400 Received: from mail-il1-x131.google.com (mail-il1-x131.google.com [IPv6:2607:f8b0:4864:20::131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8F9EDC061756 for ; Wed, 30 Jun 2021 14:17:40 -0700 (PDT) Received: by mail-il1-x131.google.com with SMTP id g3so4312865ilj.7 for ; Wed, 30 Jun 2021 14:17:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=ZJUwk8K9XYgRnENVNODKEi53QEvKtDZRquSfK1zf5vQ=; b=fCbdjy/chKXor8MDu0LlQfpggXgv0wrQYUF5rbAjETgOSYUGEGcrJfBt39eQb4wmJf TkReGRiZtYYOxSy05ZLXLmJVdKwGRAh/dY2Manac3QVQ6hYwp4rPrnnaxJpTBMBN4fzZ LB/OCdjw+QeKOXzNIslKL/368uHW2+QZFGuV6WebjPKTwXJ67YwRgd3fj1retnpJb5U/ 3HxscKo6S5mkk71TUnlyWfIDHVjFwnI5oh8FWde/nAWu4Rzdiz0x9k/S3+3jHU9aWulp /+Y37FyY4GVk3Hb4KRvmmkR7CmTnAO1weTQzGKASzCxr5aX7/OQTapM3KUNigW634apz rlWw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=ZJUwk8K9XYgRnENVNODKEi53QEvKtDZRquSfK1zf5vQ=; b=k3Qjfe5RKaurWuGtbimmqjzZUyPWd9VTpzpVjQ0XsqsUi1H4PYGbnY9zqeoCPujGTV sahK38Eb99bMsXMZ32PRaxAO42PX7JIB69qLwzPpiUzkH8RLUBb3auuMvgjsj8qOY6JU goMMEc+4ddq/42v6SP0DQE3ABm+p+6PZDSm4z5RKdbhOowkgQYCagOBP01aVnKShjd5X EkwysS+ZVsgFBWowYQ5Xu/T3JuvRiiY4gZ8dayYllcAzuG/YHeujFS6XK/aZuXhzFTQi v+Ri4eTP1s5KrUfj5/hvTM+3u+GI3KjIxNPIT+A1VPnoavtJf7C4UQSjQgxLV1b68PfJ M4bA== X-Gm-Message-State: AOAM533amoRPfxx6kOk+0WMbbdZUq45v/NdwA3BXnkfLGujs0gk46a/B nhnZRPKjs9mNr0GUBvz8kQTX4EDRcqgkfw== X-Google-Smtp-Source: ABdhPJwXkRmT64xegznljgjnD1hu1Uh/tePeWS7GxY/hMOx0WS3ujphLS/2DoeQNSQWdMso1hKrjmg== X-Received: by 2002:a92:de45:: with SMTP id e5mr20837807ilr.157.1625087859603; Wed, 30 Jun 2021 14:17:39 -0700 (PDT) Received: from [192.168.1.134] ([198.8.77.61]) by smtp.gmail.com with ESMTPSA id g5sm30868ilr.87.2021.06.30.14.17.38 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 30 Jun 2021 14:17:39 -0700 (PDT) Subject: Re: [PATCH 3/3] io_uring: tweak io_req_task_work_add To: Pavel Begunkov , io-uring@vger.kernel.org References: <24b575ea075ae923992e9ce86b61e8b51629fd29.1625086418.git.asml.silence@gmail.com> From: Jens Axboe Message-ID: <70c425a8-73dd-e15a-5a10-8ea640cdc7cd@kernel.dk> Date: Wed, 30 Jun 2021 15:17:38 -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: <24b575ea075ae923992e9ce86b61e8b51629fd29.1625086418.git.asml.silence@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 6/30/21 2:54 PM, Pavel Begunkov wrote: > Whenever possible we don't want to fallback a request. task_work_add() > will be fine if the task is exiting, so don't check for PF_EXITING, > there is anyway only a relatively small gap between setting the flag > and doing the final task_work_run(). > > Also add likely for the hot path. I'm not a huge fan of likely/unlikely, and in particular constructs like: > - if (test_bit(0, &tctx->task_state) || > + if (likely(test_bit(0, &tctx->task_state)) || > test_and_set_bit(0, &tctx->task_state)) > return 0; where the state is combined. In any case, it should be a separate change. If there's an "Also" paragraph in a patch, then that's also usually a good clue that that particular change should've been separate :-) -- Jens Axboe