From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753204AbaCASSp (ORCPT ); Sat, 1 Mar 2014 13:18:45 -0500 Received: from mail-ee0-f46.google.com ([74.125.83.46]:55173 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753083AbaCASSn (ORCPT ); Sat, 1 Mar 2014 13:18:43 -0500 Date: Sat, 1 Mar 2014 19:18:38 +0100 From: Juri Lelli To: Kirill Tkhai Cc: , Thomas Gleixner , Peter Zijlstra , Ingo Molnar , Subject: Re: [PATCH]sched/core: Return possibility to set RT and DL classes back Message-Id: <20140301191838.d15d03112b2598a671dac22c@gmail.com> In-Reply-To: <1393584643.3522.5.camel@tkhai> References: <1393496657.3522.3.camel@tkhai> <1393584643.3522.5.camel@tkhai> X-Mailer: Sylpheed 3.2.0beta5 (GTK+ 2.24.10; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 28 Feb 2014 14:50:43 +0400 Kirill Tkhai wrote: > Thomas, have you seen this? > > Nothing works at the moment: > Noticed the same once rebased on tip/master as of today. > now > > 21 root 20 0 0 0 0 S 0.0 0.0 0:00.00 watchdog/3 > 16 root 20 0 0 0 0 S 0.0 0.0 0:00.00 watchdog/2 > 11 root 20 0 0 0 0 S 0.0 0.0 0:00.00 watchdog/1 > 10 root 20 0 0 0 0 S 0.0 0.0 0:00.00 watchdog/0 > > 22 root 20 0 0 0 0 S 0.0 0.0 0:00.00 migration/3 > 17 root 20 0 0 0 0 S 0.0 0.0 0:00.00 migration/2 > 12 root 20 0 0 0 0 S 0.0 0.0 0:00.04 migration/1 > 9 root 20 0 0 0 0 S 0.0 0.0 0:00.20 migration/0 > > with fix > > 21 root RT 0 0 0 0 S 0.0 0.0 0:00.00 watchdog/3 > 16 root RT 0 0 0 0 S 0.0 0.0 0:00.00 watchdog/2 > 11 root RT 0 0 0 0 S 0.0 0.0 0:00.00 watchdog/1 > 10 root RT 0 0 0 0 S 0.0 0.0 0:00.00 watchdog/0 > > 22 root RT 0 0 0 0 S 0.0 0.0 0:00.00 migration/3 > 17 root RT 0 0 0 0 S 0.0 0.0 0:00.03 migration/2 > 12 root RT 0 0 0 0 S 0.0 0.0 0:00.00 migration/1 > 9 root RT 0 0 0 0 S 0.0 0.0 0:00.24 migration/0 > > В Чт, 27/02/2014 в 14:24 +0400, Kirill Tkhai пишет: > > [PATCH]sched/core: Return possibility to set RT and DL classes back > > > > I found that it's impossible to set RT policy for tasks at the moment. > > > > This is regression after commit [sched: Consider pi boosting in setscheduler()] > > [c365c292d05908c6ea6f32708f331e21033fe71d ] > > Fix that. > > > > Signed-off-by: Kirill Tkhai > > CC: Thomas Gleixner > > CC: Peter Zijlstra > > CC: Ingo Molnar > > --- > > kernel/sched/core.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > > index 84b23ce..30cf9ad 100644 > > --- a/kernel/sched/core.c > > +++ b/kernel/sched/core.c > > @@ -3193,6 +3193,10 @@ static void __setscheduler_params(struct task_struct *p, > > * getparam()/getattr() don't report silly values for !rt tasks. > > */ > > p->rt_priority = attr->sched_priority; > > + > > + p->normal_prio = normal_prio(p); > > + p->prio = rt_mutex_getprio(p); > > + > > set_load_weight(p); > > } > > > > I'd propose what follows, so that we can still use __setscheduler_params() as it is. Regards, - Juri >>From 73bae0ad978db6e75f492eea9adff12ec9d6d2a3 Mon Sep 17 00:00:00 2001 From: Juri Lelli Date: Sat, 1 Mar 2014 16:43:30 +0100 Subject: [PATCH] sched/core: restore __setscheduler() behavior Commit c365c29 introduced __setscheduler_params(), that is now used to only store a task's new scheduling parameters in the case it is priority boosted. Before this change, __setscheduler() was in charge of changing tasks normal_prio and prio, and the latter is used to actually perform sched_class change. Unfortunately, the commit above broke this behavior, causing tasks to remain in fair_sched_class. Restore the old behaviour setting normal_prio and prio to the right values after the __setscheduler_params() call. Signed-off-by: Juri Lelli --- kernel/sched/core.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index ee8004c..04ae20d 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3206,6 +3206,13 @@ static void __setscheduler(struct rq *rq, struct task_struct *p, { __setscheduler_params(p, attr); + /* + * Since we checked before with rt_mutex_check_prio(), + * we don't have pi waiters or our top waiter has lower + * priority (user space view) than what we got. + */ + p->prio = p->normal_prio = normal_prio(p); + if (dl_prio(p->prio)) p->sched_class = &dl_sched_class; else if (rt_prio(p->prio)) -- 1.7.9.5