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=-7.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 354B3C47082 for ; Tue, 8 Jun 2021 18:23:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 16B2761375 for ; Tue, 8 Jun 2021 18:23:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233056AbhFHSYw (ORCPT ); Tue, 8 Jun 2021 14:24:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55160 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231652AbhFHSYu (ORCPT ); Tue, 8 Jun 2021 14:24:50 -0400 Received: from mail-qt1-x82f.google.com (mail-qt1-x82f.google.com [IPv6:2607:f8b0:4864:20::82f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9AAE2C061787 for ; Tue, 8 Jun 2021 11:22:57 -0700 (PDT) Received: by mail-qt1-x82f.google.com with SMTP id a15so1781566qtx.13 for ; Tue, 08 Jun 2021 11:22:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=nGNzR+o9zZcSK3DgIga4bw5mHaZMvM8bFKU8VLJam94=; b=YD4gTOo2PMuJlmavL/H7u9Qp8mdsQlQ7TAyzX2z4mWD2a+RWlrZ9jOLmSabQsLkUUY MIMhbdSX1Z9970av0crItFOwiwGbItQaDhVjd6vYKW3wchV7NNWHLjybOxFwvMvXcVWH HPwWZR1dCtmzye5khwI6kRA+ay/MruK9N+6/hBulWfplZSYUu00aDvGnn5Nbi34UYG7A V0DBDPWjJ+HzByKvG3C0GGsOCQ0WTiKIo30TEk0fMDXSSxD+3kT/9z/tK/6S8+7hUzCX zpnqQogpobPgrHLdHxhVKr5+UoeGHMEUitA352qwRez9YrGpBwX32LdaepbJl0ahfsq1 HDmQ== 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=nGNzR+o9zZcSK3DgIga4bw5mHaZMvM8bFKU8VLJam94=; b=QKgGlrK46B62obeudG1TFZUxizASjMIxrrIvwWmO4d8cKPW6LOBnfW5tFI9ufdU0Pw 9giZjmEirwXee+nQvp6onKnBpUg7o+u1CCHs/OecXoS4M0FO966qlIkzJ5MBArUFFZwk RMgebr30zvkn+H7m5fy0yyGRQA7tw/BThOdFdvVdrulsC1n2iDMVeNdD+phnFmjHlc4V 3oC7D6GlGHloa14YBN98jK9v5Km89097Pi7Kvh6hQfNedE+mFLNX2wEva3uZPZlLT/X/ I6xvuRKZGLvyMZxCG5vEPy3uVyDHhPmQfy8nSnO1DQJ71WF80YN5CmVXxY0Rbv9P3C6d sjnA== X-Gm-Message-State: AOAM533OTMAbf6orHptWimtDxzyNFJHtIY8v5b8f/m0yEiAJjYRZJeVt WIwjnc7Omv8e0vGczOYjnVcErQ== X-Google-Smtp-Source: ABdhPJx6rJCefmbMgALRZq4VLRmbNNuDEoO3lVgsKOp/XHEZ7neGSMNeEEnuADsDxZ5MIUn+BvSu7Q== X-Received: by 2002:ac8:7590:: with SMTP id s16mr16195230qtq.259.1623176576091; Tue, 08 Jun 2021 11:22:56 -0700 (PDT) Received: from [192.168.1.4] ([177.194.59.218]) by smtp.gmail.com with ESMTPSA id q2sm6998062qkc.77.2021.06.08.11.22.50 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 08 Jun 2021 11:22:55 -0700 (PDT) Subject: Re: [PATCH v4 00/15] Add futex2 syscalls To: Florian Weimer Cc: Peter Zijlstra , Sebastian Andrzej Siewior , linux-kselftest@vger.kernel.org, joel@joelfernandes.org, Andrey Semashev , kernel@collabora.com, shuah@kernel.org, Davidlohr Bueso , Peter Oskolkov , corbet@lwn.net, krisman@collabora.com, malteskarupke@fastmail.fm, Ingo Molnar , Darren Hart , acme@kernel.org, Steven Rostedt , =?UTF-8?Q?Andr=c3=a9_Almeida?= , Thomas Gleixner , libc-alpha@sourceware.org, linux-api@vger.kernel.org, z.figura12@gmail.com, Nicholas Piggin , linux-kernel@vger.kernel.org, pgriffais@valvesoftware.com References: <20210603195924.361327-1-andrealmeid@collabora.com> <1622799088.hsuspipe84.astroid@bobo.none> <1622853816.mokf23xgnt.astroid@bobo.none> <22137ccd-c5e6-9fcc-a176-789558e9ab1e@collabora.com> <20210608122622.oxf662ruaawrtyrd@linutronix.de> <74c7f1c1-ca15-1e86-a988-a4d349ad16ef@linaro.org> <878s3k9q3a.fsf@oldenburg.str.redhat.com> From: Adhemerval Zanella Message-ID: Date: Tue, 8 Jun 2021 15:22:48 -0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <878s3k9q3a.fsf@oldenburg.str.redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/06/2021 15:19, Florian Weimer wrote: > * Adhemerval Zanella: > >> Also currently we don't have a specific usage. The proposed patch to >> add the 'pthread_mutex_lock_any' and 'pthreada_timedlock_any' [3] >> also did not gave much detail in realword usages or how it can be >> leveraged. > > The current rwlock implementation in glibc uses a torn 32-bit futex read > which is part of an atomically updated 64-bit word. That's just really, > really ugly, and I suspect we could make that go away with futex2. You are right, I had in the mind the multiple wait proposed by this patch and by the glib RFC one. Not only rwlock, but the posix semaphore might also be simplified on 32 bits I think.