Subject: Re: [RFC][PATCH] CPUSets: Move most calls to
	rebuild_sched_domains() to the workqueue
From: Peter Zijlstra <peterz@infradead.org>
To: Max Krasnyansky <maxk@qualcomm.com>
Cc: Paul Menage <menage@google.com>, Vegard Nossum <vegard.nossum@gmail.com>,
       Paul Jackson <pj@sgi.com>, a.p.zijlstra@chello.nl,
       linux-kernel@vger.kernel.org, Gautham R Shenoy <ego@in.ibm.com>
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	 <4863E4C8.9050705@qualcomm.com>
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Date: Thu, 26 Jun 2008 21:19:05 +0200
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On Thu, 2008-06-26 at 11:49 -0700, Max Krasnyansky wrote:

> > Does that mean that you can't ever call get_online_cpus() from a
> > workqueue thread?
> 
> In general it should be ok (no different from user-space task calling 
> it). But there is still circular dependency because we're calling into
> domain partitioning code.
> Below is more detailed lockdep report with your patch applied on top of 
> -rc8.
> Looks like this might be a good time to rethink overall locking in there.

Gautham has been working on some of this recently. Perhaps he can share
his patch-stack again.


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