From mboxrd@z Thu Jan 1 00:00:00 1970 From: Libo Chen Subject: Re: [PATCH]sched/rt: Do not try to push tasks if pinned task switches to RT Date: Tue, 29 Jan 2013 16:42:14 +0800 Message-ID: <51078B66.9050805@gmail.com> References: <3019251359404630@web18f.yandex.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: "linux-kernel@vger.kernel.org" , Steven Rostedt , Ingo Molnar , Peter Zijlstra , linux-rt-users , lizefan@huawei.com, jovi.zhangwei@huawei.com To: Kirill Tkhai Return-path: In-Reply-To: <3019251359404630@web18f.yandex.ru> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org =46rom: 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 candidat= es > 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, struc= t task_struct *p) > */ > if (p->on_rq && rq->curr !=3D 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 !=3D task_rq(p)) > + push_rt_task(rq) && rq !=3D task_rq(p)) I think you worry about it was excess to call push_rt_task, since the t= ask of p->nr_cpus_allowed=3D1 can`t be pushed. is that right? The task of p->nr_cpus_allowed =3D1 would`t be added to pushable_tasks= list =EF=BC=88see the enqueue_task_rt()=EF=BC=89and this push_rt_task= () need to push other tasks when rt.overloaded. So I don`t agree this patch. =20 > check_resched =3D 0; > #endif /* CONFIG_SMP */ > if (check_resched && p->prio < rq->curr->prio) > -- > To unsubscribe from this list: send the line "unsubscribe linux-rt-us= ers" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >