Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756663AbcCBCEk (ORCPT ); Tue, 1 Mar 2016 21:04:40 -0500 Received: from mail177-1.suw61.mandrillapp.com ([198.2.177.1]:4496 "EHLO mail177-1.suw61.mandrillapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754448AbcCAXvY (ORCPT ); Tue, 1 Mar 2016 18:51:24 -0500 From: Greg Kroah-Hartman Subject: [PATCH 3.14 045/130] sched,rt: Remove return value from pull_rt_task() X-Mailer: git-send-email 2.7.2 To: Cc: Greg Kroah-Hartman , , "Peter Zijlstra (Intel)" , , , , , , , , Thomas Gleixner , Byungchul Park Message-Id: <20160301234501.339263998@linuxfoundation.org> In-Reply-To: <20160301234459.768886030@linuxfoundation.org> References: <20160301234459.768886030@linuxfoundation.org> X-Report-Abuse: Please forward a copy of this message, including all headers, to abuse@mandrill.com X-Report-Abuse: You can also report abuse here: http://mandrillapp.com/contact/abuse?id=30481620.c5772556c6524870b39415ddc9d78e1b X-Mandrill-User: md_30481620 Date: Tue, 01 Mar 2016 23:51:05 +0000 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2310 Lines: 84 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peter Zijlstra commit 8046d6806247088de5725eaf8a2580b29e50ac5a upstream. In order to be able to use pull_rt_task() from a callback, we need to do away with the return value. Since the return value indicates if we should reschedule, do this inside the function. Since not all callers currently do this, this can increase the number of reschedules due rt balancing. Too many reschedules is not a correctness issues, too few are. Signed-off-by: Peter Zijlstra (Intel) Cc: ktkhai@parallels.com Cc: rostedt@goodmis.org Cc: juri.lelli@gmail.com Cc: pang.xunlei@linaro.org Cc: oleg@redhat.com Cc: wanpeng.li@linux.intel.com Cc: umgwanakikbuti@gmail.com Link: http://lkml.kernel.org/r/20150611124742.679002000@infradead.org Signed-off-by: Thomas Gleixner Signed-off-by: Byungchul Park Signed-off-by: Greg Kroah-Hartman --- kernel/sched/rt.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1652,14 +1652,15 @@ static void push_rt_tasks(struct rq *rq) ; } -static int pull_rt_task(struct rq *this_rq) +static void pull_rt_task(struct rq *this_rq) { - int this_cpu = this_rq->cpu, ret = 0, cpu; + int this_cpu = this_rq->cpu, cpu; + bool resched = false; struct task_struct *p; struct rq *src_rq; if (likely(!rt_overloaded(this_rq))) - return 0; + return; /* * Match the barrier from rt_set_overloaded; this guarantees that if we @@ -1716,7 +1717,7 @@ static int pull_rt_task(struct rq *this_ if (p->prio < src_rq->curr->prio) goto skip; - ret = 1; + resched = true; deactivate_task(src_rq, p, 0); set_task_cpu(p, this_cpu); @@ -1732,7 +1733,8 @@ skip: double_unlock_balance(this_rq, src_rq); } - return ret; + if (resched) + resched_task(this_rq->curr); } static void pre_schedule_rt(struct rq *rq, struct task_struct *prev) @@ -1835,8 +1837,7 @@ static void switched_from_rt(struct rq * if (!p->on_rq || rq->rt.rt_nr_running) return; - if (pull_rt_task(rq)) - resched_task(rq->curr); + pull_rt_task(rq); } void init_sched_rt_class(void)