From: Peter Zijlstra <peterz@infradead.org>
To: Pekka Enberg <penberg@kernel.org>
Cc: richard -rw- weinberger <richard.weinberger@gmail.com>,
Arjan van de Ven <arjan@linux.intel.com>,
penberg@cs.helsinki.fi, LKML <linux-kernel@vger.kernel.org>,
user-mode-linux-devel@lists.sourceforge.net,
Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
Jeff Dike <jdike@addtoit.com>
Subject: Re: [REGRESSION] um: rcu_sched_state detected stall on CPU 0
Date: Fri, 15 Oct 2010 09:48:48 +0200 [thread overview]
Message-ID: <1287128928.29097.1235.camel@twins> (raw)
In-Reply-To: <AANLkTi=vYFv+S=D6O06Nys4cjU7KHWv11d_VdLGmLyf6@mail.gmail.com>
On Fri, 2010-10-15 at 10:02 +0300, Pekka Enberg wrote:
> On Fri, Oct 15, 2010 at 2:44 AM, richard -rw- weinberger
> <richard.weinberger@gmail.com> wrote:
> > On Thu, Oct 14, 2010 at 9:50 PM, Arjan van de Ven
> <arjan@linux.intel.com> wrote:
> >> On 10/14/2010 11:27 AM, richard -rw- weinberger wrote:
> >>>
> >>> Hi Arjan!
> >>>
> >>> This commit causes some problems on UML.
> >>>
> >> that is extremely weird.
> >>>
> >>> The kernel freezes after a few seconds until it gets some input.
> >>> e.g: When I run top it stops refreshing the process list until i
> press a
> >>> button.
> >>
> >> a slab timer change (to not be as critical) causing global timer
> issues....
> >> that's very obviously not a problem with this patch.
> >> has this been seem anywhere except UML ?
> >
> > A small update:
> > It seems that CONFIG_NO_HZ is broken on UML. :-(
> >
> > CONFIG_NO_HZ + CONFIG_SLAB: works
> > CONFIG_NO_HZ + CONFIG_SLAB + your patch: broken
> > CONFIG_NO_HZ + CONFIG_SLUB: broken
> >
> > CONFIG_SLAB + your patch: works
> > CONFIG_SLAB: works
> > CONFIG_SLUB: works
>
> Thanks for testing! Thomas, Ingo, Peter, I'm not sure who maintains
> CONFIG_NO_HZ so I CC'd you. The problem here is that Arjan's
> deferrable timers patch in SLAB triggered something that looks like a
> latent bug with UML and NOHZ.
Thomas does mostly, but if its UML specific, I guess its Jeff Dike
you'll be wanting to talk to, since he's the arch maintainer.
next prev parent reply other threads:[~2010-10-15 7:49 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-14 18:27 [REGRESSION] um: rcu_sched_state detected stall on CPU 0 richard -rw- weinberger
2010-10-14 19:50 ` Arjan van de Ven
2010-10-14 20:06 ` richard -rw- weinberger
2010-10-14 23:44 ` richard -rw- weinberger
2010-10-15 7:02 ` Pekka Enberg
2010-10-15 7:48 ` Peter Zijlstra [this message]
2010-10-15 9:24 ` richard -rw- weinberger
2010-10-16 15:27 ` richard -rw- weinberger
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