From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754880Ab3A2Imt (ORCPT ); Tue, 29 Jan 2013 03:42:49 -0500 Received: from mail-pa0-f46.google.com ([209.85.220.46]:48536 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754647Ab3A2Imr (ORCPT ); Tue, 29 Jan 2013 03:42:47 -0500 Message-ID: <51078B66.9050805@gmail.com> Date: Tue, 29 Jan 2013 16:42:14 +0800 From: Libo Chen User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:17.0) Gecko/20130107 Thunderbird/17.0.2 MIME-Version: 1.0 To: Kirill Tkhai CC: "linux-kernel@vger.kernel.org" , Steven Rostedt , Ingo Molnar , Peter Zijlstra , linux-rt-users , lizefan@huawei.com, jovi.zhangwei@huawei.com Subject: Re: [PATCH]sched/rt: Do not try to push tasks if pinned task switches to RT References: <3019251359404630@web18f.yandex.ru> In-Reply-To: <3019251359404630@web18f.yandex.ru> 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 From: Libo Chen On 2013-1-29 4:23, Kirill Tkhai wrote: > Just switched pinned task is not able to be pushed. If the rq had had > several RT tasks before they have already been considered as candidates > to be pushed (or pulled). > > Signed-off-by: Kirill V Tkhai > CC: Steven Rostedt > CC: Ingo Molnar > CC: Peter Zijlstra > CC: linux-rt-users > --- > kernel/sched/rt.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c > index 4e8f0f4..5f7d92b 100644 > --- a/kernel/sched/rt.c > +++ b/kernel/sched/rt.c > @@ -1925,9 +1925,9 @@ static void switched_to_rt(struct rq *rq, struct task_struct *p) > */ > if (p->on_rq && rq->curr != p) { > #ifdef CONFIG_SMP > - if (rq->rt.overloaded && push_rt_task(rq) && > + if (rq->rt.overloaded && p->nr_cpus_allowed > 1 && > /* Don't resched if we changed runqueues */ > - rq != task_rq(p)) > + push_rt_task(rq) && rq != task_rq(p)) I think you worry about it was excess to call push_rt_task, since the task of p->nr_cpus_allowed=1 can`t be pushed. is that right? The task of p->nr_cpus_allowed =1 would`t be added to pushable_tasks list （see the enqueue_task_rt()）and this push_rt_task() need to push other tasks when rt.overloaded. So I don`t agree this patch. > check_resched = 0; > #endif /* CONFIG_SMP */ > if (check_resched && p->prio < rq->curr->prio) > -- > To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >