From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965075AbbDJO2m (ORCPT ); Fri, 10 Apr 2015 10:28:42 -0400 Received: from mail-wg0-f53.google.com ([74.125.82.53]:33164 "EHLO mail-wg0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933028AbbDJO2k (ORCPT ); Fri, 10 Apr 2015 10:28:40 -0400 Message-ID: <1428676114.4309.112.camel@gmail.com> Subject: Re: [rfc patch v2] rt,nohz_full: fix nohz_full for PREEMPT_RT_FULL From: Mike Galbraith To: Sebastian Andrzej Siewior Cc: linux-rt-users , LKML , Thomas Gleixner , rostedt@goodmis.org, John Kacur Date: Fri, 10 Apr 2015 16:28:34 +0200 In-Reply-To: <20150410141552.GC3057@linutronix.de> References: <20150216111822.GA21649@linutronix.de> <1424258514.3819.39.camel@gmail.com> <20150309134535.GA13768@linutronix.de> <1425911771.30469.8.camel@gmail.com> <1425980136.3507.17.camel@gmail.com> <1426153093.4190.2.camel@gmail.com> <1426222405.17611.7.camel@gmail.com> <20150410141552.GC3057@linutronix.de> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.16.0 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2015-04-10 at 16:15 +0200, Sebastian Andrzej Siewior wrote: > * Mike Galbraith | 2015-03-13 05:53:25 [+0100]: > > > First of all, a task being ticked and trying to shut the tick down > > will > > fail to do so due to having just awakened ksoftirqd, so let > > ksoftirqd > > try to do that after SOFTIRQ_TIMER processing. Secondly, should > > the > > tick be shut down, we may livelock in hrtimer-cancel() because in - > > rt > > a callback may be running. Break the loop, and let > > tick_nohz_restart() > > know that the timer is busy so it can bail. > > So with this patch > http://marc.info/?l=linux-rt-users&m=142866940327602&w=2 Oh duh, too much of a hurry, I'll give that a spin. -Mike