Re: [Xen-devel] RFC: [0/2] Remove netloop by lazy copying in netback

[Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>]

On Tue, Mar 27, 2007 at 02:50:19PM +0100, Keir Fraser wrote:
> 
> PV-on-otherwise-unmodified-guest). Of course we'd only be introducing a
> dependency for a *backend* driver here.

Well I'm still hoping to have a zero-copy dom0 => domU path :)

> Your thought of using the accessed bit is rather neat. I believe it is
> guaranteed that if we test-and-clear a pte, and see A==0, then no TLB can
> cache that pte. If so, I think this could be a winner.

Yes that assumption is used elsewhere too so it should be fine.

I've checked again and the accessed bit is certainly present on ppc
as well as ia64.  The only I don't know is if it's present on the
nested page tables on ia64 but I see no reasons why it wouldn't be.

Cheers,
-- 
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Email: Herbert Xu ~{PmV>HI~} <herbert@xxxxxxxxxxxxxxxxxxx>
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