Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933097AbaBUNCJ (ORCPT ); Fri, 21 Feb 2014 08:02:09 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:47674 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933073AbaBUNCD (ORCPT ); Fri, 21 Feb 2014 08:02:03 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Mike Galbraith , Peter Zijlstra , Thomas Gleixner , Li Zefan , Luis Henriques Subject: [PATCH 3.5 16/60] sched,rt: fix isolated CPUs leaving root_task_group indefinitely throttled Date: Fri, 21 Feb 2014 13:00:43 +0000 Message-Id: <1392987687-15367-17-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.9.0 In-Reply-To: <1392987687-15367-1-git-send-email-luis.henriques@canonical.com> References: <1392987687-15367-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.5.7.31 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Mike Galbraith commit e221d028bb08b47e624c5f0a31732c642db9d19a upstream. Root task group bandwidth replenishment must service all CPUs, regardless of where the timer was last started, and regardless of the isolation mechanism, lest 'Quoth the Raven, "Nevermore"' become rt scheduling policy. Signed-off-by: Mike Galbraith Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1344326558.6968.25.camel@marge.simpson.net Signed-off-by: Thomas Gleixner Cc: Li Zefan Signed-off-by: Luis Henriques --- kernel/sched/rt.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 8480912..06c3c6f 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -788,6 +788,19 @@ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun) const struct cpumask *span; span = sched_rt_period_mask(); +#ifdef CONFIG_RT_GROUP_SCHED + /* + * FIXME: isolated CPUs should really leave the root task group, + * whether they are isolcpus or were isolated via cpusets, lest + * the timer run on a CPU which does not service all runqueues, + * potentially leaving other CPUs indefinitely throttled. If + * isolation is really required, the user will turn the throttle + * off to kill the perturbations it causes anyway. Meanwhile, + * this maintains functionality for boot and/or troubleshooting. + */ + if (rt_b == &root_task_group.rt_bandwidth) + span = cpu_online_mask; +#endif for_each_cpu(i, span) { int enqueue = 0; struct rt_rq *rt_rq = sched_rt_period_rt_rq(rt_b, i); -- 1.9.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/