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Date: Mon, 3 Jun 2024 17:23:06 -0700
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Subject: Re: [PATCH v4 2/7] mm: multi-gen LRU: Have secondary MMUs participate
 in aging
From: Sean Christopherson <seanjc@google.com>
To: James Houghton <jthoughton@google.com>
Cc: Yu Zhao <yuzhao@google.com>, Andrew Morton <akpm@linux-foundation.org>, 
	Paolo Bonzini <pbonzini@redhat.com>, Albert Ou <aou@eecs.berkeley.edu>, 
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On Mon, Jun 03, 2024, James Houghton wrote:
> On Mon, Jun 3, 2024 at 4:03=E2=80=AFPM Sean Christopherson <seanjc@google=
.com> wrote:
> > But before we do that, I think we need to perform due dilegence (or pro=
vide 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 wor=
th the cost.
>=20
> 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 i=
s
enabled.  If the test fails because that doesn't hold true, then we _want_ =
the
failure.