Re: [PATCH v4 2/7] mm: multi-gen LRU: Have secondary MMUs participate in aging

Sean Christopherson
2024-06-04T00:23:21Z

On Mon, Jun 03, 2024, James Houghton wrote:
> On Mon, Jun 3, 2024 at 4:03 PM Sean Christopherson <seanjc@google.com> wrote:
> > But before we do that, I think we need to perform due dilegence (or provide data)
> > showing that having KVM take mmu_lock for write in the "fast only" API provides
> > better total behavior. I.e. that the additional accuracy is indeed worth the cost.
>
> That sounds good to me. I'll drop the Kconfig. I'm not really sure
> what to do about the self-test, but that's not really all that
> important.

Enable it only on architectures+setups that are guaranteed to implement the
fast-only API? E.g. on x86, it darn well better be active if the TDP MMU is
enabled. If the test fails because that doesn't hold true, then we _want_ the
failure.