Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754365AbaGVJrt (ORCPT ); Tue, 22 Jul 2014 05:47:49 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:57142 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753392AbaGVJrr (ORCPT ); Tue, 22 Jul 2014 05:47:47 -0400 Date: Tue, 22 Jul 2014 11:47:40 +0200 From: Peter Zijlstra To: Bruno Wolff III Cc: Dietmar Eggemann , Josh Boyer , "mingo@redhat.com" , "linux-kernel@vger.kernel.org" , "H. Peter Anvin" , Thomas Gleixner Subject: Re: Scheduler regression from caffcdd8d27ba78730d5540396ce72ad022aff2c Message-ID: <20140722094740.GJ12054@laptop.lan> References: <53C7B247.2070309@arm.com> <20140717123502.GL19379@twins.programming.kicks-ass.net> <20140718053449.GA2039@wolff.to> <20140718101633.GP9918@twins.programming.kicks-ass.net> <20140718130126.GA2401@wolff.to> <20140718141648.GE20603@laptop.programming.kicks-ass.net> <20140718145040.GG12054@laptop.lan> <20140718161602.GH12054@laptop.lan> <20140721163528.GA10433@wolff.to> <20140721165212.GO3935@laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140721165212.GO3935@laptop> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 21, 2014 at 06:52:12PM +0200, Peter Zijlstra wrote: > On Mon, Jul 21, 2014 at 11:35:28AM -0500, Bruno Wolff III wrote: > > Is there more I can do to help with this now? Or should I just wait for > > patches to test? > > Yeah, sorry, was wiped out today. I'll go stare harder at the P4 > topology setup code tomorrow. Something fishy there. Does this make your machine boot again (while giving an error)? It tries to robustify the topology setup a bit, crashing on crap input should be avoided if possible of course. I'll go stare at the x86/P4 topology code like promised. --- Subject: sched: Robustify topology setup From: Peter Zijlstra Date: Mon Jul 21 23:07:06 CEST 2014 We hard assume that higher topology levels are strict supersets of lower levels. Detect, warn and try to fixup when we encounter this violated. Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/n/tip-cgp9j2tk0qnunhtpps3udsom@git.kernel.org --- kernel/sched/core.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6480,6 +6480,20 @@ struct sched_domain *build_sched_domain( sched_domain_level_max = max(sched_domain_level_max, sd->level); child->parent = sd; sd->child = child; + + if (!cpumask_subset(sched_domain_span(child), + sched_domain_span(sd))) { + pr_err("BUG: arch topology borken\n"); +#ifdef CONFIG_SCHED_DEBUG + pr_err(" the %s domain not a subset of the %s domain\n", + child->name, sd->name); +#endif + /* Fixup, ensure @sd has at least @child cpus. */ + cpumask_or(sched_domain_span(sd), + sched_domain_span(sd), + sched_domain_span(child)); + } + } set_domain_attribute(sd, attr); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/