From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933626AbaD3NGf (ORCPT ); Wed, 30 Apr 2014 09:06:35 -0400 Received: from mail-ee0-f43.google.com ([74.125.83.43]:57560 "EHLO mail-ee0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751435AbaD3NGe (ORCPT ); Wed, 30 Apr 2014 09:06:34 -0400 Message-ID: <1398863189.26071.97.camel@marge.simpson.net> Subject: Re: [ANNOUNCE] 3.14-rt1 From: Mike Galbraith To: Steven Rostedt Cc: Nicholas Mc Guire , Sebastian Andrzej Siewior , linux-rt-users , LKML , Thomas Gleixner , John Kacur , Clark Williams Date: Wed, 30 Apr 2014 15:06:29 +0200 In-Reply-To: <1398843793.26071.52.camel@marge.simpson.net> References: <20140411185739.GA6644@linutronix.de> <1397918766.5436.16.camel@marge.simpson.net> <1398411635.11930.45.camel@marge.simpson.net> <1398501491.12941.5.camel@marge.simpson.net> <1398520699.28726.22.camel@marge.simpson.net> <1398661784.30930.33.camel@marge.simpson.net> <1398676186.30930.49.camel@marge.simpson.net> <20140428101805.75032f45@gandalf.local.home> <1398695832.14475.10.camel@marge.simpson.net> <1398748869.5514.81.camel@marge.simpson.net> <20140429201308.63292691@gandalf.local.home> <1398843793.26071.52.camel@marge.simpson.net> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2014-04-30 at 09:43 +0200, Mike Galbraith wrote: > On Tue, 2014-04-29 at 20:13 -0400, Steven Rostedt wrote: > > On Tue, 29 Apr 2014 07:21:09 +0200 > > Mike Galbraith wrote: > > > > > On Mon, 2014-04-28 at 16:37 +0200, Mike Galbraith wrote: > > > > > > > > Seems that migrate_disable() must be called before taking the lock as > > > > > it is done in every other location. > > > > > > > > And for tasklist_lock, seems you also MUST do that prior to trylock as > > > > well, else you'll run afoul of the hotplug beast. > > > > > > Bah. Futzing with dmesg while stress script is running is either a very > > > bad idea, or a very good test. Both virgin 3.10-rt and 3.12-rt with new > > > bugs squashed will deadlock. > > > > > > Too bad I kept on testing, I liked the notion that hotplug was solid ;-) > > > > I was able to stress cpu hotplug on 3.12-rt after applying the > > following patch. > > > > If there's no complaints about it. I'm going to add this to the 3.12-rt > > stable tree. As without it, it fails horribly with the cpu hotplug > > stress test, and I wont release a stable kernel that does that. > > My local boxen are happy, 64 core box with 14-rt seems happy as well, > though I couldn't let it burn for long. And 3.12 looks stable on 64 core DL980 as well. (If it survived a 24 hour busy+stress session I'd still likely fall outta my chair though) My kinda sorta 3.12-rt enterprise to be kernel wasn't stable on DL980, while appearing just fine on small boxen, which made me suspect that there was still a big box something lurking, only raising its ugly head in the fatter kernel. That wasn't an rt problem after all, someone in enterprise land just didn't stack their goody pile quite high enough while wedging upstream into the stable base kernel, which bent rt. The End.. I hope. I've had enough hotplug entertainment for a while. -Mike