Date: Tue, 28 Jul 2009 10:11:57 +0900
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
       Lee Schermerhorn <lee.schermerhorn@hp.com>,
       KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>, miaox@cn.fujitsu.com,
       Ingo Molnar <mingo@elte.hu>, Peter Zijlstra <a.p.zijlstra@chello.nl>,
       Christoph Lameter <cl@linux-foundation.org>,
       Paul Menage <menage@google.com>, Nick Piggin <nickpiggin@yahoo.com.au>,
       y-goto@jp.fujitsu.com, Pekka Enberg <penberg@cs.helsinki.fi>,
       linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [BUG] set_mempolicy(MPOL_INTERLEAV) cause kernel panic
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On Mon, 27 Jul 2009 18:02:50 -0700 (PDT)
David Rientjes <rientjes@google.com> wrote:

> On Tue, 28 Jul 2009, KAMEZAWA Hiroyuki wrote:
> 
> > > The problem originally reported here doesn't appear to have anything to do 
> > > with hotplug, it looks like it is the result of Lee's observation that 
> > > ia64 defaults top_cpuset's mems to N_POSSIBLE, which _should_ have been 
> > > updated by cpuset_init_smp(). 
> > cpuset_init_smp() just updates cpuset's mask.
> > init's task->mems_allowed is intizialized independently from cpuset's mask.
> > 
> 
> Presumably the bug is that N_HIGH_MEMORY is not a subset of N_ONLINE at 
> this point on ia64.
> 
N_HIGH_MEMORY is must be subset of N_ONLINE, at the any moment. Hmm,
I'll look into what happens in ia64 world.

> > Could you teach me a pointer for Lee's observation ?
> > 
> 
> http://marc.info/?l=linux-kernel&m=124767909310293
> 
Aha, my patch is very similar to Lee's one.
And he said "hotplug is issue", yes. it is.


Thanks,
-Kame

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