Re: [RFC, PATCH 00/12] userfaultfd: working set tracking for VM guest memory

[David Hildenbrand (Arm)]

> 
> The other thing is, as I mentioned in the other email, I still don't know
> how the current RW protection would work for anonymous.  I don't yet think
> the user swapper can read the anon page with RW-protected pgtables.  So far
> my understanding is maybe you only care about shmem so it's fine, but it'll
> always be great to confirm with you.

I wonder if uffdio_move could be used for a swapper implementation instead?

If we ever have to read from a protnone page, maybe we could teach ptrace access
to do it, or have something that can read from prot_none areas -- like
uffdio_copy, which can write to prot-none areas.

-- 
Cheers,

David