Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758111AbcDEL5q (ORCPT ); Tue, 5 Apr 2016 07:57:46 -0400 Received: from www.linutronix.de ([62.245.132.108]:37752 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758079AbcDEL5o (ORCPT ); Tue, 5 Apr 2016 07:57:44 -0400 Subject: Re: [PREEMPT-RT] [PATCH] s390/cpum_sf: Remove superfluous SMP function call To: rcochran@linutronix.de, Heiko Carstens References: <1459765640-13599-1-git-send-email-anna-maria@linutronix.de> <20160405104912.GC3937@osiris> <57039DC2.6090907@linutronix.de> <20160405112336.GB6890@osiris> <20160405113637.GC6890@osiris> <20160405115129.GE30124@linutronix.de> Cc: Anna-Maria Gleixner , Martin Schwidefsky , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, rt@linutronix.de From: Sebastian Andrzej Siewior Message-ID: <5703A836.7030708@linutronix.de> Date: Tue, 5 Apr 2016 13:57:42 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Icedove/38.7.0 MIME-Version: 1.0 In-Reply-To: <20160405115129.GE30124@linutronix.de> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001,URIBL_BLOCKED=0.001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 848 Lines: 24 On 04/05/2016 01:51 PM, rcochran@linutronix.de wrote: > On Tue, Apr 05, 2016 at 01:36:38PM +0200, Heiko Carstens wrote: >> On Tue, Apr 05, 2016 at 01:23:36PM +0200, Heiko Carstens wrote: >>> Subsequently, in this case, the setup_pmc_cpu() call will be executed on >>> the wrong cpu. >> >> .. or to illustrate this behaviour: the following patch (white space >> damaged due to copy-paste) results in the following: > > I guess you are missing the following commit? ? > cpu/hotplug: Move online calls to hotplugged cpu No, Heiko is right here. If one of the "CPU_DOWN_PREPARE" fails then the following CPU_DOWN_FAILED will be invoked on the correct CPU. However if we are further down the road and the final ARCH specific "die" failed (just before CPU_DYING) are invoked then we get this done on the wrong CPU. > Thanks, > Richard Sebastian