Re: KVM: guest: only batch user pte updates

Jeremy Fitzhardinge
2009-02-11T16:57:45Z

Avi Kivity wrote:
> Jeremy Fitzhardinge wrote:
>>>
>>> Yes. It seems however that only set_pte_at/pte_update/_defer are
>>> used under significatly long lazy mmu sections (long as in number of
>>> updates). Is it worthwhile to bother (and risk) batching kernel pte
>>> updates ?
>>>
>>
>> Well, that depends on how expensive each update is. For something
>> like kunmap atomic, I think combining the clear+tlb flush probably is
>> worthwhile.
>
> I agree, kmap_atomic() is fairly common.

(Not that we're actually batching it at present; we need to work out
proper semantics for nesting batches...)

J