Re: [patch 2/2] mspec driver

From: Jes Sorensen
Date: Fri Mar 17 2006 - 09:01:33 EST


>>>>> "Nick" == Nick Piggin <nickpiggin@xxxxxxxxxxxx> writes:

Nick> Jes Sorensen wrote:
>> + vma->vm_flags |= (VM_IO | VM_LOCKED | VM_RESERVED | VM_PFNMAP);

Nick> VM_PFNMAP actually has a fairly specific meaning [unlike the
Nick> rest of them :)] so you should be careful with it. Actually if
Nick> you set vm_pgoff in the right way, then that should enable you
Nick> to do COWs on these areas if that is what you want.

Yup, I went through that when I started using it. I think you guided
me through it :-)

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.

Cheers,
Jes
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