No, I can't immediately see why it shouldn't work. My main concern
would probably still be about the latency of the population stage as I
can't see why it would improve compared to what we have now, because my
> feeling is this is linked with the sharedness property of guest_memfd.
If the problem is the "pagecache" overhead, then yes, it will be a
harder nut to crack. But maybe there are some low-hanging fruits to
optimize? Finding the main cause for the added overhead would be
interesting.
Can you compare uffdio_copy() when using anonymous memory vs. shmem?
That's likely the best we could currently achieve with guest_memfd.
There is the tools/testing/selftests/mm/uffd-stress benchmark, not sure
if that is of any help; it SEGFAULTS for me right now with a (likely)
division by 0.
--
Cheers,
David / dhildenb