Re: [PATCH 3/3] KVM: x86/mmu: Buffer nested MMU split_desc_cache only by default capacity

[David Matlack]

On Fri, Jun 24, 2022 at 05:18:08PM +0000, Sean Christopherson wrote:
> Buffer split_desc_cache, the cache used to allcoate rmap list entries,
> only by the default cache capacity (currently 40), not by doubling the
> minimum (513).  Aliasing L2 GPAs to L1 GPAs is uncommon, thus eager page
> splitting is unlikely to need 500+ entries.  And because each object is a
> non-trivial 128 bytes (see struct pte_list_desc), those extra ~500
> entries means KVM is in all likelihood wasting ~64kb of memory per VM.
> 
> Link: https://lore.kernel.org/all/YrTDcrsn0%2F+alpzf@xxxxxxxxxx
> Cc: David Matlack <dmatlack@xxxxxxxxxx>
> Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>

Thanks for the cleanups!

Reviewed-by: David Matlack <dmatlack@xxxxxxxxxx>