From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753446Ab2DJJIv (ORCPT ); Tue, 10 Apr 2012 05:08:51 -0400 Received: from mailout-de.gmx.net ([213.165.64.23]:46348 "HELO mailout-de.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751150Ab2DJJIu (ORCPT ); Tue, 10 Apr 2012 05:08:50 -0400 X-Authenticated: #14349625 X-Provags-ID: V01U2FsdGVkX18INBdL/3AIMHq1/fViYRbUItO+luMXMeL7wjbDiV I/2twYN8utvQdi Message-ID: <1334048925.7524.21.camel@marge.simpson.net> Subject: Re: RFC [patch] sched,cgroup_sched: convince RT_GROUP_SCHED throttle to work From: Mike Galbraith To: LKML Cc: Peter Zijlstra , Ingo Molnar Date: Tue, 10 Apr 2012 11:08:45 +0200 In-Reply-To: <1333792489.12677.58.camel@marge.simpson.net> References: <1333444106.9072.4.camel@marge.simpson.net> <1333444788.9072.9.camel@marge.simpson.net> <1333789124.12677.15.camel@marge.simpson.net> <1333792489.12677.58.camel@marge.simpson.net> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.1 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2012-04-07 at 11:54 +0200, Mike Galbraith wrote: > With this patch, the thing appears to work perfectly, but it doesn't > look correct, since I'm futzing with ->rt_time where I should not. s/doesn't look/definitely isn't. This failed the "definitely works so may live on despite horrific appearance" test anyway, so how about just stop pretending root isn't global instead? sched,rt: fix isolated CPUs leaving root_task_group indefinitely throttled Root task group bandwidth replenishment must service all CPUs regardless of where it was last started. Signed-off-by: Mike Galbraith --- kernel/sched/rt.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -782,6 +782,19 @@ static int do_sched_rt_period_timer(stru 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);