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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_2 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 A1293C4320A for ; Wed, 4 Aug 2021 16:48:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8386D60C41 for ; Wed, 4 Aug 2021 16:48:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239625AbhHDQsR (ORCPT ); Wed, 4 Aug 2021 12:48:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:34824 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229798AbhHDQsP (ORCPT ); Wed, 4 Aug 2021 12:48:15 -0400 Received: from oasis.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 132FC60238; Wed, 4 Aug 2021 16:48:01 +0000 (UTC) Date: Wed, 4 Aug 2021 12:47:55 -0400 From: Steven Rostedt To: Sebastian Andrzej Siewior Cc: Jens Axboe , Peter Zijlstra , Daniel Wagner , Thomas Gleixner , LKML , linux-rt-users@vger.kernel.org Subject: Re: [ANNOUNCE] v5.14-rc4-rt4 Message-ID: <20210804124755.21ca7e3d@oasis.local.home> In-Reply-To: <20210804163119.t4c7bkpdk33byxtx@linutronix.de> References: <20210804131731.GG8057@worktop.programming.kicks-ass.net> <4f549344-1040-c677-6a6a-53e243c5f364@kernel.dk> <20210804153308.oasahcxjmcw7vivo@linutronix.de> <20210804154743.niogqvnladdkfgi2@linutronix.de> <7c946918-ae0d-6195-6a78-b019f9bc1fd3@kernel.dk> <20210804121704.1587c41b@oasis.local.home> <20210804162231.rfj5i736lqc4nsio@linutronix.de> <20210804122541.741cf858@oasis.local.home> <20210804163119.t4c7bkpdk33byxtx@linutronix.de> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 4 Aug 2021 18:31:19 +0200 Sebastian Andrzej Siewior wrote: > CPU-local wake-ups just set NEED_RESCHED and wait for preempt_enable() > to do the magic. Just because the code not perform wake_up() now does > not mean it will not do so in the future. Also it is here as an example > which might be copied somewhere else. Does this mean all local_irq_disable/enable() is audited? What do you do for; local_irq_disable(); [..] wakeup_process(x); /* on local CPU */ [..] local_irq_enable(); And if local_irq_disable() is not used anymore, or seldom, what harm would it be to add a preemption check to that caller? And change local_irq_enable() that is used internally by other atom functions be called __local_irq_enable()? Not to mention that we could just open code that too: if (IS_ENABLED(CONFIG_PREEMPT_RT)) { local_irq_enable(); preempt_check_resched(); } And make it ugly enough that nobody will want to copy it :-) -- Steve