From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932315AbbCIOpv (ORCPT ); Mon, 9 Mar 2015 10:45:51 -0400 Received: from www.linutronix.de ([62.245.132.108]:35882 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753929AbbCIOpr (ORCPT ); Mon, 9 Mar 2015 10:45:47 -0400 Message-ID: <54FDB215.1090205@linutronix.de> Date: Mon, 09 Mar 2015 15:45:41 +0100 From: Sebastian Andrzej Siewior User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.4.0 MIME-Version: 1.0 To: Mike Galbraith CC: linux-rt-users , LKML , Thomas Gleixner , rostedt@goodmis.org, John Kacur Subject: Re: [patch-3.18.7-rt1] sched/context-tracking: fix PREEMPT_LAZY explosions References: <20150216111822.GA21649@linutronix.de> <1424258514.3819.39.camel@gmail.com> <20150309134535.GA13768@linutronix.de> <1425911771.30469.8.camel@gmail.com> In-Reply-To: <1425911771.30469.8.camel@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit 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 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/09/2015 03:36 PM, Mike Galbraith wrote: > On Mon, 2015-03-09 at 14:45 +0100, Sebastian Andrzej Siewior wrote: >> * Mike Galbraith | 2015-02-18 12:21:54 [+0100]: >> >>> On Mon, 2015-02-16 at 12:18 +0100, Sebastian Andrzej Siewior wrote: >>> >>>> Known issues: >>>> >>>> - lazy preempt on x86_64 leads to a crash with some load. >>> >>> The below still works for me. (it doesn't make nohz_full actually work >>> in rt, but at least folks who want to tinker with it can do so) >> So your box still crashes without it? >> >> The thing is I tried to reproduce it and it does not occur anymore. >> Neither in KVM nor on real HW. > > Heh, well that's interesting, I just presumed it would still explode > because you said it would. I'll beat on it any let you know if I'm > carrying a placebo patch or not :) Hehe. By the time I did 3.18-rt1 I was surprised that the disable- lazy-preempt-on-x8664 was still there because I assumed it has been fixed in the v3.14 series. So I left it as-is (including the broken message) and wanted to drop later an eye on it. And after you dropped a few patches to fix it I assumed (even more) that it is still broken :) > > -Mike > Sebastian