From: Michal Schmidt <mschmidt@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>,
linux-kernel@vger.kernel.org,
"Eric W. Biederman" <ebiederm@xmission.com>,
Jon Masters <jcm@redhat.com>,
Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH] kthread: always create the kernel threads with normal priority
Date: Tue, 8 Jan 2008 10:54:28 +0100 [thread overview]
Message-ID: <20080108105428.2fb04bdd@brian.englab.brq.redhat.com> (raw)
In-Reply-To: <20080107092956.419b5f91.akpm@linux-foundation.org>
On Mon, 7 Jan 2008 09:29:56 -0800
Andrew Morton <akpm@linux-foundation.org> wrote:
> On Mon, 7 Jan 2008 12:09:04 +0100 Ingo Molnar <mingo@elte.hu> wrote:
>
> >
> > > > This causes a practical problem. When a runaway real-time task
> > > > is eating 100% CPU and we attempt to put the CPU offline,
> > > > sometimes we block while waiting for the creation of the
> > > > highest-priority "kstopmachine" thread.
> >
> > sched-devel.git has new mechanisms against runaway RT tasks.
> > There's a new RLIMIT_RTTIME rlimit - if an RT task exceeds that
> > rlimit then it is sent SIGXCPU.
>
> Is that "total RT CPU time" or "elapsed time since last schedule()"?
>
> If the former, it is not useful for this problem.
It's "runtime since last sleep" so it is useful.
I still think the kthread patch is good to have anyway. The user can
have other reasons to change kthreadd's priority/cpumask.
Michal
next prev parent reply other threads:[~2008-01-08 9:55 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-17 22:43 [PATCH] kthread: run kthreadd with max priority SCHED_FIFO Michal Schmidt
2007-12-17 23:00 ` Jon Masters
2007-12-22 9:30 ` Andrew Morton
2007-12-22 9:52 ` Jon Masters
2007-12-22 10:11 ` Andrew Morton
2007-12-22 10:18 ` Jon Masters
2007-12-22 10:39 ` Mike Galbraith
2007-12-22 10:52 ` Andrew Morton
2007-12-22 11:21 ` Jon Masters
2007-12-23 8:50 ` Mike Galbraith
2008-01-07 10:06 ` [PATCH] kthread: always create the kernel threads with normal priority Michal Schmidt
2008-01-07 10:25 ` Andrew Morton
2008-01-07 11:09 ` Ingo Molnar
2008-01-07 17:29 ` Andrew Morton
2008-01-07 17:47 ` Peter Zijlstra
2008-01-08 9:54 ` Michal Schmidt [this message]
2008-01-07 13:18 ` Michal Schmidt
2008-01-08 16:22 ` Ingo Molnar
2008-01-07 11:22 ` Remy Bohmer
2008-01-07 13:10 ` Michal Schmidt
2008-01-07 15:53 ` Remy Bohmer
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