On Wed, Feb 23, 2022 at 3:32 PM Ben Gardon <bgardon@xxxxxxxxxx> wrote:
>
> On Wed, Feb 2, 2022 at 5:02 PM David Matlack <dmatlack@xxxxxxxxxx> wrote:
> >
> > Update the page stats in __rmap_add() rather than at the call site. This
> > will avoid having to manually update page stats when splitting huge
> > pages in a subsequent commit.
> >
> > No functional change intended.
> >
>
> Reviewed-by: Ben Gardon <bgardon@xxxxxxxxxx>
>
> > Signed-off-by: David Matlack <dmatlack@xxxxxxxxxx>
> > ---
> > arch/x86/kvm/mmu/mmu.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> > index c2f7f026d414..ae1564e67e49 100644
> > --- a/arch/x86/kvm/mmu/mmu.c
> > +++ b/arch/x86/kvm/mmu/mmu.c
> > @@ -1621,6 +1621,8 @@ static void __rmap_add(struct kvm *kvm,
> > rmap_head = gfn_to_rmap(gfn, sp->role.level, slot);
> > rmap_count = pte_list_add(cache, spte, rmap_head);
> >
> > + kvm_update_page_stats(kvm, sp->role.level, 1);
> > +
Strictly speaking, this is a functional change since you're moving the
stat update after the rmap update, but there's no synchronization on
the stats anyway, so I don't think it matters if it's updated before
or after.
> > if (rmap_count > RMAP_RECYCLE_THRESHOLD) {
> > kvm_unmap_rmapp(kvm, rmap_head, NULL, gfn, sp->role.level, __pte(0));
> > kvm_flush_remote_tlbs_with_address(
> > @@ -2831,7 +2833,6 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot,
> >
> > if (!was_rmapped) {
> > WARN_ON_ONCE(ret == RET_PF_SPURIOUS);
> > - kvm_update_page_stats(vcpu->kvm, level, 1);
> > rmap_add(vcpu, slot, sptep, gfn);
> > }
> >
> > --
> > 2.35.0.rc2.247.g8bbb082509-goog
> >
