From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753838AbdFSKPF convert rfc822-to-8bit (ORCPT ); Mon, 19 Jun 2017 06:15:05 -0400 Received: from mout.gmx.net ([212.227.17.22]:58134 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751090AbdFSKPD (ORCPT ); Mon, 19 Jun 2017 06:15:03 -0400 Message-ID: <1497867291.19618.52.camel@gmx.de> Subject: Re: [ANNOUNCE] v4.11.5-rt1 From: Mike Galbraith To: Sebastian Andrzej Siewior Cc: Thomas Gleixner , LKML , linux-rt-users , Steven Rostedt Date: Mon, 19 Jun 2017 12:14:51 +0200 In-Reply-To: <20170619085206.n2n22lpdfsoqbp5m@linutronix.de> References: <20170616105610.rbc6itylcrsla56l@linutronix.de> <1497687277.6908.31.camel@gmx.de> <20170619085206.n2n22lpdfsoqbp5m@linutronix.de> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.20.5 Mime-Version: 1.0 Content-Transfer-Encoding: 8BIT X-Provags-ID: V03:K0:dbVKG7FF8VKqPBHszZEIkD2o4/haUGKq6b/04KKy2qH/vcHEhED r11DY2w7eYJ2o9eKzFI+HQ2ZQ7E+zwXLbexEMwJ0qH4w3jOwsOvzQ8khJ7aZ+bSGUyOA6L/ lExMKy7AOCvTl9HMWlMgNUiVj8XYhZU38Nqqh5RzZOi/7s4zsjWTbKAD/uuJuI0b2sGHVSC 0LPLMUZA2LcMBqAKizo4w== X-UI-Out-Filterresults: notjunk:1;V01:K0:M6qVrt4Pd04=:yatApIASkvshcD4gL7wEe2 HwJkIJaOuVwFRsg4PqzEUhOlVrn8yO/1tJTMibNljUYlFlHOVKLmBqTX8wfxXm/hRHBGECrp6 lpTRMcJco5jPkPovluNkSnRefuJrw1LhH9qevfMj1E1F9GDDkopMIhfYs4DShD5IlTH5NQOfI W0cn0CCqqqCigBhd6sBIgu7W36PF1/2GShDrDO9tkOa7a4TmGqsrbKM9M/aRKoyMB1+IQ8t5Z HPm5g+fvHF8wRW1qyCePZ5pSccwk1ZFwsNeUoa+Q/Ul2SPzyhAEbA0qV/t4GFcqWizHUhRzk/ 6qv6QP9C/lH6PhCOle+8Q1HChwnukzb/rrWgn77j9GBiXDZj/aTRJNAYhj6xCFC/aSOvwOqGS Hc6XyXg4yodYQxpjVl+k1GETy9QmaIEPby7I7abIjWA5ZWGwX1ROJDTL581iA1RWyH/sEQWWd hqCbNDLRzgACBf+sSWbSUbfYkJPvQrc7/hFX8EqIQcJyHaiAzpSUtWxnYK+9uIxIiRuTs9woF Oc7eZqe+k5gxqLKw/iFGVoGn9+P3eYhE/lj2TA/spNwOZ7eQII+kdM5294Dn7oqGXAicoI8ay l5Gll3UX5Hza8eUeP4OLe+n5HzQ7ZCUkhF+m58FP1vvp9L7Ebt+aVHCcF+y3Yn4UseeLUw17v 8+VhOe7jJB2TkVKCbnGxI4Grwr48tq6UYuNuyBmdH3ceQoRiE2F05FTvH+p3evj4CFgOyiyDd Nk4KwUAUJ/+pZ/+aQYDkQzmJvZCb+TohogaJIFcnKdLZD9eh8Ml6hRiFRqjFVTgxecnL7UIZi TroIK2X Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2017-06-19 at 10:52 +0200, Sebastian Andrzej Siewior wrote: > On 2017-06-17 10:14:37 [+0200], Mike Galbraith wrote: > > > During that rebase, migrate_disable() was changed to no longer map to > > preempt_disable() for nonrt, but some patches still assume it does.  It > > now depends upon PREEMPT_COUNT, the RT workaround in futex.c induces > > grumbling in nonrt builds with PREEMPT_COUNT enabled. > > argh, right. It was planned to get it merged upstream but due to > $reasons we never got that far. For that reason I would simply revert > that change and let migrate_disable() map to preempt_disable() as it did > earlier. Ok, doesn't matter for RT testing. What does matter, is that... diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 30b24f774198..10e832da70b6 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2284,7 +2284,7 @@ EXPORT_SYMBOL(wake_up_process); */ int wake_up_lock_sleeper(struct task_struct *p) { - return try_to_wake_up(p, TASK_ALL, WF_LOCK_SLEEPER); + return try_to_wake_up(p, TASK_UNINTERRUPTIBLE, WF_LOCK_SLEEPER); } ...appears to be inducing lost futex wakeups. Scratch that "appears", changing it to TASK_NORMAL just fixed my DL980 running otherwise absolutely pristine 4.9-rt21, after having double verified that rt20 works fine.  Now to go back to 4.11/master/tip-rt, make sure that the little bugger really really REALLY ain't fscking with me for the sheer fun of it, futexes being made of pure evil :) My testcase is to run futex_wait -n 4 in a modest sized loop.  Odd thing is that it only reproduces on the DL980 if I let it use multiple sockets, pin it to one, and all is peachy, (rather seems to be given) whereas on desktop box, the hang is far more intermittent, but there. -Mike