Re: [PATCH 2/2] KVM: Scalable memslots implementation

[David Hildenbrand <david@redhat.com>]

>> The new implementation also uses standard kernel {rb,interval}-tree
>> and hash table implementation as its basic data structures, so it
>> automatically benefits from any generic improvements to these.
>>
>> All for the low price of just 174 net lines of code added.
> 
> I think the best thing to do here is to provide a patch series that
> splits the individual changes so that they can be reviewed and their
> separate merits evaluated.
> 
> Another thing that I dislike about KVM_SET_USER_MEMORY_REGION is that
> IMO userspace should provide all memslots at once, for an atomic switch
> of the whole memory array.  (Or at least I would like to see the code;
> it might be a bit tricky because you'll need code to compute the
> difference between the old and new arrays and invoke
> kvm_arch_prepare/commit_memory_region).  I'm not sure how that would
> interact with the active/inactive pair that you introduce here.
> 

+1

One issue I am aware of is resizing/splitting slots, especially due to 
arrays like rmap + dirty bitmaps.

BTW: what are your thoughts regarding converting the rmap array on 
x86-64 into some dynamic datastructre (xarray etc)? Has that already 
been discussed?

> Paolo
> 


-- 
Thanks,

David / dhildenb