Re: [PATCH 00/13] KVM: MMU: fast page fault

Marcelo Tosatti
2012-04-11T01:51:01Z

On Tue, Apr 10, 2012 at 01:04:13PM +0300, Avi Kivity wrote:
> On 04/09/2012 10:46 PM, Marcelo Tosatti wrote:
> > Perhaps the mmu_lock hold times by get_dirty are a large component here?
>
> That's my concern, because it affects the scaling of migration for wider
> guests.
>
> > If that can be alleviated, not only RO->RW faults benefit.
>
> Those are the most common types of faults on modern hardware, no?

Depends on your workload, of course. If there is memory pressure,
0->PRESENT might be very frequent. My point is that reduction of
mmu_lock contention is a good thing overall.