Message-ID: <441AC3A4.801@sgi.com>
Date: Fri, 17 Mar 2006 15:11:48 +0100
From: Jes Sorensen <jes@sgi.com>
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To: Nick Piggin <nickpiggin@yahoo.com.au>
CC: Andrew Morton <akpm@osdl.org>, torvalds@osdl.org,
       linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, hch@lst.de,
       cotte@de.ibm.com, Hugh Dickins <hugh@veritas.com>
Subject: Re: [patch 2/2] mspec driver
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Nick Piggin wrote:
> Jes Sorensen wrote:
>> We don't want COW here as the access is backed by special behavior in
>> the memory controller. We only allow shared mappings for that reason.
>>
> No problem, I think you should just stop using the VM_PFNMAP flag then.
> [Linus should jump in here if I'm wrong ;)]

I'd have to go back and find the discussion to verify, but if I
remember correctly the conclusion was that I needed to use it in
order to make sure that vm_normal_page() didn't start thinking it was
in fact a real page, ie. VM_PFNMAP + never a COW mapping..

Chers,
Jes


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