From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753144AbbCWMZP (ORCPT ); Mon, 23 Mar 2015 08:25:15 -0400 Received: from terminus.zytor.com ([198.137.202.10]:41371 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752644AbbCWMYk (ORCPT ); Mon, 23 Mar 2015 08:24:40 -0400 Date: Mon, 23 Mar 2015 05:24:11 -0700 From: tip-bot for Brian Silverman Message-ID: Cc: tglx@linutronix.de, brian@peloton-tech.com, hpa@zytor.com, stable@vger.kernel.org, peterz@infradead.org, linux-kernel@vger.kernel.org, mingo@kernel.org Reply-To: stable@vger.kernel.org, hpa@zytor.com, brian@peloton-tech.com, tglx@linutronix.de, linux-kernel@vger.kernel.org, peterz@infradead.org, mingo@kernel.org In-Reply-To: <1424305436-6716-1-git-send-email-brian@peloton-tech.com> References: <1424305436-6716-1-git-send-email-brian@peloton-tech.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched: Fix RLIMIT_RTTIME when PI-boosting to RT Git-Commit-ID: 746db9443ea57fd9c059f62c4bfbf41cf224fe13 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 746db9443ea57fd9c059f62c4bfbf41cf224fe13 Gitweb: http://git.kernel.org/tip/746db9443ea57fd9c059f62c4bfbf41cf224fe13 Author: Brian Silverman AuthorDate: Wed, 18 Feb 2015 16:23:56 -0800 Committer: Ingo Molnar CommitDate: Mon, 23 Mar 2015 10:47:55 +0100 sched: Fix RLIMIT_RTTIME when PI-boosting to RT When non-realtime tasks get priority-inheritance boosted to a realtime scheduling class, RLIMIT_RTTIME starts to apply to them. However, the counter used for checking this (the same one used for SCHED_RR timeslices) was not getting reset. This meant that tasks running with a non-realtime scheduling class which are repeatedly boosted to a realtime one, but never block while they are running realtime, eventually hit the timeout without ever running for a time over the limit. This patch resets the realtime timeslice counter when un-PI-boosting from an RT to a non-RT scheduling class. I have some test code with two threads and a shared PTHREAD_PRIO_INHERIT mutex which induces priority boosting and spins while boosted that gets killed by a SIGXCPU on non-fixed kernels but doesn't with this patch applied. It happens much faster with a CONFIG_PREEMPT_RT kernel, and does happen eventually with PREEMPT_VOLUNTARY kernels. Signed-off-by: Brian Silverman Signed-off-by: Peter Zijlstra (Intel) Cc: austin@peloton-tech.com Cc: Link: http://lkml.kernel.org/r/1424305436-6716-1-git-send-email-brian@peloton-tech.com Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index f0f831e..62671f5 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3034,6 +3034,8 @@ void rt_mutex_setprio(struct task_struct *p, int prio) } else { if (dl_prio(oldprio)) p->dl.dl_boosted = 0; + if (rt_prio(oldprio)) + p->rt.timeout = 0; p->sched_class = &fair_sched_class; }