Re: [patch 2/4] mmu_notifier: Callbacks to invalidate address ranges

On Fri, Feb 01, 2008 at 03:19:32PM -0800, Christoph Lameter wrote:
On Fri, 1 Feb 2008, Robin Holt wrote:

We are getting this callout when we transition the pte from a read-only
to read-write. Jack and I can not see a reason we would need that
callout. It is causing problems for xpmem in that a write fault goes
to get_user_pages which gets back to do_wp_page that does the callout.

Right. You placed it there in the first place. So we can drop the code
from do_wp_page?

No, we need a callout when we are becoming more restrictive, but not
when becoming more permissive. I would have to guess that is the case
for any of these callouts. It is for both GRU and XPMEM. I would
expect the same is true for KVM, but would like a ruling from Andrea on
that.

Thanks,
Robin
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