On 03.02.21 14:46, Paolo Bonzini wrote:
On 03/02/21 14:44, David Hildenbrand wrote:
BTW: what are your thoughts regarding converting the rmap array on
x86-64 into some dynamic datastructre (xarray etc)? Has that already
been discussed?
Hasn't been discussed---as always, showing the code would be the best
way to start a discussion. :)
If only a workday would have more hours :)
However, note that the TDP MMU does not need an rmap at all. Since that
one is getting ready to become the default, the benefits of working on
the rmap would be quite small and only affect nested virtualization.
Right, but we currently always have to allocate it.
8 bytes per 4k page, 8 bytes per 2M page, 8 bytes per 1G page.
The 4k part alone is 0.2% of the memblock size.
For a 1 TB memslot we might "waste" > 2 GB on rmap arrays.
(that's why I am asking :) )
--
Thanks,
David / dhildenb
