From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932991AbaBAEV4 (ORCPT ); Fri, 31 Jan 2014 23:21:56 -0500 Received: from moutng.kundenserver.de ([212.227.126.171]:56323 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932368AbaBAEVz (ORCPT ); Fri, 31 Jan 2014 23:21:55 -0500 Message-ID: <1391228495.5348.82.camel@marge.simpson.net> Subject: Re: [PATCH RT 4/8] rtmutex: use a trylock for waiter lock in trylock From: Mike Galbraith To: Sebastian Andrzej Siewior Cc: Steven Rostedt , linux-kernel@vger.kernel.org, linux-rt-users , Thomas Gleixner , Carsten Emde , John Kacur Date: Sat, 01 Feb 2014 05:21:35 +0100 In-Reply-To: <20140131220737.GF21238@linutronix.de> References: <20140116015824.201732155@goodmis.org> <20140116020324.637491369@goodmis.org> <1389841737.5418.14.camel@marge.simpson.net> <20140116232228.0f3cfb89@gandalf.local.home> <1389935832.5449.23.camel@marge.simpson.net> <20140131220737.GF21238@linutronix.de> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 X-Provags-ID: V02:K0:lbx0DHmqP/xrwp4BCmJ5Kq+4dnAaz5/4koBIInCNXBH P87XGfGJOmMz2VtsxnyHXuPGx2E2/sSbthB078CItMVjogVNDC Hr/xOevmk/fwFn/aG5oM158cLLuCgIHH2vV26gEYyeb4xtECyU 99qA3tNOC8EB9Fel17R/WQQAYPS38E3QpmG6aN6YsLaKtTd5W/ XxJ20Lb1NGRroRH5gF8nzpa6CYEnS3sncxQ3Mn3xuU5ZW6Zqit uFtm7IG6iTMDifdHYoBXxx4LsB3y1Kc0hybZ3W1WbyRyGp0t/0 6Y/m+cVbaKj5yB7MOD2QajSuNNMSIz0qxSz2tvrf4Qcs8V9Oy9 UZ9nsyL9zA7GyIiK+77nPKI7ivdIxt3NXPn2w4z3k/cdIAZTeY w6/papMhxtqnQ== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2014-01-31 at 23:07 +0100, Sebastian Andrzej Siewior wrote: > * Mike Galbraith | 2014-01-17 06:17:12 [+0100]: > > >On Thu, 2014-01-16 at 23:22 -0500, Steven Rostedt wrote: > >> On Thu, 16 Jan 2014 04:08:57 +0100 > >> Mike Galbraith wrote: > >> > >> > On Wed, 2014-01-15 at 20:58 -0500, Steven Rostedt wrote: > >> > > >> > > >> > > 3.2.53-rt76-rc1 stable review patch. > >> > > If anyone has any objections, please let me know. > >> > > >> > Not sure this is needed without the tglx don't unconditionally raise > >> > timer softirq patch, and with that patch applied in the form it exists > >> > in 3.12-rt9, as well as this one, you'll still eventually deadlock. > >> > >> Hmm, I'll have to take a look. This sounds to be missing from all the > >> stable -rt kernels. I'll be pulling in the latest updates from 3.12-rt > >> soon. > > > >Below are the two deadlocks I encountered with 3.12-rt9, which has both > >$subject and timers-do-not-raise-softirq-unconditionally.patch applied. > > This patch was introduced because we had a deadlock in > run_local_timers() which took a sleeping lock in hardirq context. This > seem not to be the case in v3.2 therefore I would suggest not to take > this patch here because it does not fix anything. > > Mike, do you see these deadlocks with 3.12.*-rt11 as well? No. I beat 64 core box hard configured both nohz_idle and nohz_full, the only thing that fell out was the nohz_full irqs enabled warning. If Stevens patch didn't fix them, it did make them hide very well. -Mike