Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752436AbdLSQnE (ORCPT ); Tue, 19 Dec 2017 11:43:04 -0500 Received: from mail.kernel.org ([198.145.29.99]:55184 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750773AbdLSQnD (ORCPT ); Tue, 19 Dec 2017 11:43:03 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0F02320853 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=rostedt@goodmis.org Date: Tue, 19 Dec 2017 11:43:00 -0500 From: Steven Rostedt To: Sebastian Andrzej Siewior Cc: Grygorii Strashko , linux-rt-users , LKML Subject: Re: [v4.14-rt][report] arm: run: stress-ng --class os --all 0 -t 5m Message-ID: <20171219114300.2156577d@gandalf.local.home> In-Reply-To: <20171219153310.aq2rxw6umgyyku3p@linutronix.de> References: <20171219082739.d6oxzkjkdicfu3hq@linutronix.de> <20171219100202.3017a79f@gandalf.local.home> <20171219150418.vz6hkpf4uuangb4q@linutronix.de> <20171219102839.367fa92d@gandalf.local.home> <20171219153310.aq2rxw6umgyyku3p@linutronix.de> X-Mailer: Claws Mail 3.14.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1124 Lines: 28 On Tue, 19 Dec 2017 16:33:10 +0100 Sebastian Andrzej Siewior wrote: > On 2017-12-19 10:28:39 [-0500], Steven Rostedt wrote: > > On Tue, 19 Dec 2017 16:04:18 +0100 > > Sebastian Andrzej Siewior wrote: > > > > > > > > > > The above just seems wrong. local_irq_disable() should imply > > > > local_bh_disable(), as it doesn't let softirqs run either. > > > > > > Where does local_irq_disable() imply this? > > > > If it doesn't explicitly do so, it probably should. How can we have a > > softirq execute when irqs are disabled? > > There are not. With local_bh_disable() the softirq will run on > local_bh_enable(). Without it (and with or without local_irq_disable()) > the softirq won't run but wakeup the ksoftirq thread. We can't do the > wake while holding the hrtimer lock. This is not RT specific. > Then there should be a comment there, as it is way too subtle. As local_bh_disable() is usually used only to prevent softirq from running on the current CPU during a critical period. Where, here we are using it to avoid a wake up of ksoftirqd. -- Steve