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Date: Wed, 8 Feb 2017 13:21:55 +0100
From: Michal Hocko <mhocko@kernel.org>
Subject: Re: mm: deadlock between get_online_cpus/pcpu_alloc
Message-ID: <20170208122154.GJ5686@dhcp22.suse.cz>
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To: Thomas Gleixner <tglx@linutronix.de>
Cc: Christoph Lameter <cl@linux.com>, Mel Gorman <mgorman@techsingularity.net>, Vlastimil Babka <vbabka@suse.cz>, Dmitry Vyukov <dvyukov@google.com>, Tejun Heo <tj@kernel.org>, "linux-mm@kvack.org" <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@kernel.org>, Peter Zijlstra <peterz@infradead.org>, syzkaller <syzkaller@googlegroups.com>, Andrew Morton <akpm@linux-foundation.org>

On Wed 08-02-17 13:02:07, Thomas Gleixner wrote:
> On Wed, 8 Feb 2017, Michal Hocko wrote:
[...]
> > [1] http://lkml.kernel.org/r/20170207201950.20482-1-mhocko@kernel.org
> 
> Well, yes. It's simple, but from an RT point of view I really don't like
> it as we have to fix it up again.

I thought that preempt_disable would turn into migrate_disable or
something like that which shouldn't cause too much trouble. Or am I
missing something? Which part of the patch is so RT unfriendly?
-- 
Michal Hocko
SUSE Labs

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