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From: Avi Kivity <avi@qumranet.com>
Subject: [ofa-general] Re: [RFC] Notifier for Externally Mapped Memory (EMM)
Date: Wed, 05 Mar 2008 07:09:55 +0200
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Cc: Nick Piggin <npiggin@suse.de>, Andrea Arcangeli <andrea@qumranet.com>,
	kvm-devel@lists.sourceforge.net, Kanoj Sarcar <kanojsarcar@yahoo.com>,
	Roland Dreier <rdreier@cisco.com>,
	Jack Steiner <steiner@sgi.com>, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, daniel.blueman@quadrics.com,
	Robin Holt <holt@sgi.com>, general@lists.openfabrics.org,
	akpm@linux-foundation.org, Christoph Lameter <clameter@sgi.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
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Peter Zijlstra wrote:
> On Tue, 2008-03-04 at 14:35 -0800, Christoph Lameter wrote:
>
>   
>> RCU means that the callbacks occur in an atomic context.
>>     
>
> Not really, if it requires moving the VM locks to sleepable locks under
> a .config option, I think its also fair to require PREEMPT_RCU.
>
> OTOH, if you want to unconditionally move the VM locks to sleepable
> locks you have a point.
>   

Isn't that out of the question for .25?

I really wish we can get the atomic variant in now, and add on 
sleepability in .26, updating users if necessary.

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.