Messages in this thread | | | Subject | Re: [PATCH -mm v8 5/7] mmu-notifier: add clear_young callback | From | Paolo Bonzini <> | Date | Thu, 16 Jul 2015 13:35:02 +0200 |
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On 15/07/2015 21:16, Andres Lagar-Cavilla wrote: >> > +static int kvm_mmu_notifier_clear_young(struct mmu_notifier *mn, >> > + struct mm_struct *mm, >> > + unsigned long start, >> > + unsigned long end) >> > +{ >> > + struct kvm *kvm = mmu_notifier_to_kvm(mn); >> > + int young, idx; > For reclaim, the clear_flush_young notifier may blow up the secondary > pte to estimate the access pattern, depending on hardware support (EPT > access bits available in Haswell onwards, not sure about AMD, PPC, > etc).
It seems like this problem is limited to pre-Haswell EPT.
I'm okay with the patch. If we find problems later we can always add a parameter to kvm_age_hva so that it effectively doesn't do anything on clear_young.
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo
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