From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753465Ab2DWL5a (ORCPT ); Mon, 23 Apr 2012 07:57:30 -0400 Received: from mail-bk0-f46.google.com ([209.85.214.46]:61269 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752335Ab2DWL53 (ORCPT ); Mon, 23 Apr 2012 07:57:29 -0400 Message-ID: <4F9543A4.5000705@gmail.com> Date: Mon, 23 Apr 2012 13:57:24 +0200 From: Juri Lelli User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20120329 Thunderbird/11.0.1 MIME-Version: 1.0 To: Peter Zijlstra CC: tglx@linutronix.de, mingo@redhat.com, rostedt@goodmis.org, cfriesen@nortel.com, oleg@redhat.com, fweisbec@gmail.com, darren@dvhart.com, johan.eker@ericsson.com, p.faure@akatech.ch, linux-kernel@vger.kernel.org, claudio@evidence.eu.com, michael@amarulasolutions.com, fchecconi@gmail.com, tommaso.cucinotta@sssup.it, nicola.manica@disi.unitn.it, luca.abeni@unitn.it, dhaval.giani@gmail.com, hgu1972@gmail.com, paulmck@linux.vnet.ibm.com, raistlin@linux.it, insop.song@ericsson.com, liming.wang@windriver.com Subject: Re: [PATCH 05/16] sched: SCHED_DEADLINE policy implementation. References: <1333696481-3433-1-git-send-email-juri.lelli@gmail.com> <1333696481-3433-6-git-send-email-juri.lelli@gmail.com> <1335180849.28150.121.camel@twins> In-Reply-To: <1335180849.28150.121.camel@twins> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/23/2012 01:34 PM, Peter Zijlstra wrote: > On Fri, 2012-04-06 at 09:14 +0200, Juri Lelli wrote: >> + /* >> + * At this point, the deadline really should be "in >> + * the future" with respect to rq->clock. If it's >> + * not, we are, for some reason, lagging too much! >> + * Anyway, after having warn userspace abut that, >> + * we still try to keep the things running by >> + * resetting the deadline and the budget of the >> + * entity. >> + */ >> + if (dl_time_before(dl_se->deadline, rq->clock)) { >> + WARN_ON_ONCE(1); > > Doing printk() and friends from scheduler context isn't actually safe > and can lock up your machine.. there's a printk_sched() that > maybe-sorta-kinda can get your complaints out.. > Thanks! I'll look at it. >> + dl_se->deadline = rq->clock + dl_se->dl_deadline; >> + dl_se->runtime = dl_se->dl_runtime; >> + } - Juri