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Subject: Re: KVM bug, git bisected
From: Peter Zijlstra <peterz@infradead.org>
To: Rik van Riel <riel@redhat.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>, linux-kernel@vger.kernel.org,
       Ingo Molnar <mingo@elte.hu>
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Date: Mon, 29 Mar 2010 18:44:42 +0200
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On Mon, 2010-03-29 at 18:29 +0200, Peter Zijlstra wrote:

> > Peter, would it be safe to increase PREEMPT_BITS to eg. 10?

One reason this all sucks massive is that nesting that many spinlocks
creates a terribly large !preempt section.

There is nothing that stops someone from creating 64k vmas (or more when
someone raises that sysctl) and try this, that's just utter suckage.