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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 0FF96C4361B for ; Mon, 7 Dec 2020 17:47:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D4AAA21D42 for ; Mon, 7 Dec 2020 17:47:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726289AbgLGRra (ORCPT ); Mon, 7 Dec 2020 12:47:30 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:38020 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726002AbgLGRr3 (ORCPT ); Mon, 7 Dec 2020 12:47:29 -0500 From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1607363208; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=afDC03InAXZsSNwfef2vWGfi5DTW9+sgf5g7C6+1NsA=; b=OVGEyYBnrdqJ3N9sFPwlQrVzeJHhVqcqrNQs0QQcb/zYkPL75uFBdNWMvCSf0aHat5BQ+2 WS+sgSAbDcFNFRDd2QVF73wORuMfErYzzzNR2qpn388m7r3qHzYrQAePHAjA4tDMz/Q1rV Hr6NZmQQnXcroCax9DkDjOH1SjBcWD3N4rOxDMy/oGzGE9C+eWVcHcXIxeC6Z1k3dZptYA D3Moctk8j+C1ecigV1sM46jO9+I7cJvRb4G8gaoAIZMyNRG34jzSmQCKMWuK91vM4KxIV4 G/k4jubAGTeT6OZGV6AzwZL17w+Om50zQ33bu7ckB+W6FLW22Ge/9QfySJ57xA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1607363208; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=afDC03InAXZsSNwfef2vWGfi5DTW9+sgf5g7C6+1NsA=; b=LVuezxMdPq/58zrhUDFJlNPYpS7Q4X5cB8etMiMenYAdqOJyFmfYqCSr3bd39bQzH1pEBa iLbmIai15q1357CQ== To: Peter Zijlstra Cc: LKML , Marco Elver , kasan-dev , "Paul E. McKenney" , Ingo Molnar , Frederic Weisbecker , Will Deacon , Naresh Kamboju , syzbot+23a256029191772c2f02@syzkaller.appspotmail.com, syzbot+56078ac0b9071335a745@syzkaller.appspotmail.com, syzbot+867130cb240c41f15164@syzkaller.appspotmail.com Subject: Re: [patch 3/3] tick: Annotate tick_do_timer_cpu data races In-Reply-To: <20201207120943.GS3021@hirez.programming.kicks-ass.net> References: <20201206211253.919834182@linutronix.de> <20201206212002.876987748@linutronix.de> <20201207120943.GS3021@hirez.programming.kicks-ass.net> Date: Mon, 07 Dec 2020 18:46:47 +0100 Message-ID: <87y2i94igo.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 07 2020 at 13:09, Peter Zijlstra wrote: > On Sun, Dec 06, 2020 at 10:12:56PM +0100, Thomas Gleixner wrote: >> + if (data_race(tick_do_timer_cpu) == TICK_DO_TIMER_BOOT) { > > I prefer the form: > > if (data_race(tick_do_timer_cpu == TICK_DO_TIMER_BOOT)) { > > But there doesn't yet seem to be sufficient data_race() usage in the > kernel to see which of the forms is preferred. Do we want to bike-shed > this now and document the outcome somewhere? Yes please before we get a gazillion of patches changing half of them half a year from now. Thanks, tglx