Re: Nick's core remove PageReserved broke vmware...

From: Gleb Natapov
Date: Thu Nov 03 2005 - 10:54:23 EST


On Thu, Nov 03, 2005 at 03:37:44PM +0000, Hugh Dickins wrote:
> > > I don't much want to add another path into copy_pte_range, actually
> > > copying pages. If the process really wants DMA into such areas,
> > > then it should contain the code for the child to COW them itself?
> >
> > How do you do that, say, for a stack page, or global data section?
>
> And why do you need to?
>
> You seem to be saying, actually DONTCOPY isn't enough of a solution,
> we need something else instead.
>
DONTCOPY is a good solution for the problem it solves, but there are
other problems :). One of them is what should we do if only part of the
page is used for DMA and other part contains information needed by the
forked child? We can copy such pages on fork or declare such state to be
user error. I can live with both.

--
Gleb.
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