From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754267AbaI2PD3 (ORCPT ); Mon, 29 Sep 2014 11:03:29 -0400 Received: from service87.mimecast.com ([91.220.42.44]:51366 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751347AbaI2PD1 convert rfc822-to-8bit (ORCPT ); Mon, 29 Sep 2014 11:03:27 -0400 Message-ID: <542974DE.8050203@arm.com> Date: Mon, 29 Sep 2014 16:03:58 +0100 From: Juri Lelli User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.0 MIME-Version: 1.0 To: Kirill Tkhai , "linux-kernel@vger.kernel.org" CC: Peter Zijlstra , Kirill Tkhai , Ingo Molnar , Juri Lelli Subject: Re: [PATCH 2/2] sched/dl: Cleanup prio_changed_dl() References: <20140927084044.1634.60573.stgit@localhost> <20140927084104.1634.88783.stgit@localhost> In-Reply-To: <20140927084104.1634.88783.stgit@localhost> X-OriginalArrivalTime: 29 Sep 2014 15:03:23.0020 (UTC) FILETIME=[83697CC0:01CFDBF6] X-MC-Unique: 114092916032504201 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 Hi Kirill, On 27/09/14 09:41, Kirill Tkhai wrote: > From: Kirill Tkhai > > Now rq->curr task can't be dequeued in this function > (it's possible only in __schedule()). > Could you please detail about "before", with a reference to the commit that made this further change necessary? Thanks a lot, - Juri > Also, delete "else" branch which is dead code. > > Signed-off-by: Kirill Tkhai > --- > kernel/sched/deadline.c | 50 +++++++++++++++++++++++------------------------ > 1 file changed, 24 insertions(+), 26 deletions(-) > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > index 63f8b4a..38b4f19 100644 > --- a/kernel/sched/deadline.c > +++ b/kernel/sched/deadline.c > @@ -1638,35 +1638,33 @@ static void switched_to_dl(struct rq *rq, struct task_struct *p) > static void prio_changed_dl(struct rq *rq, struct task_struct *p, > int oldprio) > { > - if (task_on_rq_queued(p) || rq->curr == p) { > + if (!task_on_rq_queued(p)) > + return; > #ifdef CONFIG_SMP > - /* > - * This might be too much, but unfortunately > - * we don't have the old deadline value, and > - * we can't argue if the task is increasing > - * or lowering its prio, so... > - */ > - if (!rq->dl.overloaded) > - pull_dl_task(rq); > - > - /* > - * If we now have a earlier deadline task than p, > - * then reschedule, provided p is still on this > - * runqueue. > - */ > - if (dl_time_before(rq->dl.earliest_dl.curr, p->dl.deadline) && > - rq->curr == p) > - resched_curr(rq); > -#else > - /* > - * Again, we don't know if p has a earlier > - * or later deadline, so let's blindly set a > - * (maybe not needed) rescheduling point. > - */ > + /* > + * This might be too much, but unfortunately > + * we don't have the old deadline value, and > + * we can't argue if the task is increasing > + * or lowering its prio, so... > + */ > + if (!rq->dl.overloaded) > + pull_dl_task(rq); > + /* > + * If we now have a earlier deadline task than p, > + * then reschedule, provided p is still on this > + * runqueue. > + */ > + if (dl_time_before(rq->dl.earliest_dl.curr, p->dl.deadline) && > + rq->curr == p) > resched_curr(rq); > +#else > + /* > + * Again, we don't know if p has a earlier > + * or later deadline, so let's blindly set a > + * (maybe not needed) rescheduling point. > + */ > + resched_curr(rq); > #endif /* CONFIG_SMP */ > - } else > - switched_to_dl(rq, p); > } > > const struct sched_class dl_sched_class = { > >