From: Steven Rostedt <rostedt@goodmis.org>
To: Kirill Tkhai <tkhai@yandex.ru>
Cc: Nicholas Mc Guire <der.herr@hofr.at>,
Peter Zijlstra <peterz@infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>,
linux-rt-users <linux-rt-users@vger.kernel.org>
Subject: Re: [PATCH]sched/rt: Do not try to push tasks if pinned task switches to RT
Date: Thu, 20 Mar 2014 14:21:39 -0400 [thread overview]
Message-ID: <20140320142139.04a40e66@gandalf.local.home> (raw)
In-Reply-To: <3618231394627028@web10g.yandex.ru>
On Wed, 12 Mar 2014 16:23:48 +0400
Kirill Tkhai <tkhai@yandex.ru> wrote:
> > would there not need to be a check for p->migrate_disable ?
> > push_rt_task() is not checking and so a high prio RT task
> > preemting a low prio RT task in a migrate_disable() section
> > would actually push it off this cpu ? atleast I did not
> > find why that would not happen.
>
> Hi, Nicholas!
>
> p is not rq->curr, so its p->migrate_disable state is already updated and
> it can't be pushed (nr_cpus_allowed == 1 and it's not pushable).
>
> (If I understand right, that you worry about this).
>
Correct. If p has migrate_disabled set and scheduled out, then when it
gets scheduled out, its cpu affinity gets set to only the current cpu
and nr_cpu_allowed to 1. No need to check here if p->migrate_disabled is
set.
-- Steve
next prev parent reply other threads:[~2014-03-20 18:21 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-29 14:45 Re:[PATCH]sched/rt: Do not try to push tasks if pinned task switches to RT Kirill Tkhai
2014-03-12 10:18 ` [PATCH]sched/rt: " Steven Rostedt
2014-03-12 10:39 ` Nicholas Mc Guire
2014-03-12 12:23 ` Kirill Tkhai
2014-03-20 18:21 ` Steven Rostedt [this message]
2014-03-12 13:33 ` Peter Zijlstra
-- strict thread matches above, loose matches on Subject: below --
2013-01-28 20:23 Kirill Tkhai
2013-01-29 8:42 ` Libo Chen
2013-01-29 13:26 ` Steven Rostedt
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