KVM MMU: fix kvm_mmu_zap_page() and its calling path
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From: Xiao Guangrong on 13 Apr 2010 22:20 Marcelo Tosatti wrote: > On Tue, Apr 13, 2010 at 09:34:14AM +0800, Xiao Guangrong wrote: >> >> Marcelo Tosatti wrote: >> >>>> @@ -1483,8 +1483,8 @@ static int mmu_zap_unsync_children(struct kvm *kvm, >>>> for_each_sp(pages, sp, parents, i) { >>>> kvm_mmu_zap_page(kvm, sp); >>>> mmu_pages_clear_parents(&parents); >>>> + zapped++; >>>> } >>>> - zapped += pages.nr; >>>> kvm_mmu_pages_init(parent, &parents, &pages); >>>> } >>> Don't see why this is needed? The for_each_sp loop uses pvec.nr. >> I think mmu_zap_unsync_children() should return the number of zapped pages then we >> can adjust the number of free pages in kvm_mmu_change_mmu_pages(), but pages.nr no >> only includes the unsync/zapped pages but also includes their parents. > > Oh i see. I think its safer to check for list_empty then to rely on > proper accounting there, like __kvm_mmu_free_some_pages does. Do you mean that we'd better add WARN_ON(list_empty()) code in kvm_mmu_zap_page()? Thanks, Xiao -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Marcelo Tosatti on 14 Apr 2010 13:00
On Wed, Apr 14, 2010 at 10:14:29AM +0800, Xiao Guangrong wrote: > > > Marcelo Tosatti wrote: > > On Tue, Apr 13, 2010 at 09:34:14AM +0800, Xiao Guangrong wrote: > >> > >> Marcelo Tosatti wrote: > >> > >>>> @@ -1483,8 +1483,8 @@ static int mmu_zap_unsync_children(struct kvm *kvm, > >>>> for_each_sp(pages, sp, parents, i) { > >>>> kvm_mmu_zap_page(kvm, sp); > >>>> mmu_pages_clear_parents(&parents); > >>>> + zapped++; > >>>> } > >>>> - zapped += pages.nr; > >>>> kvm_mmu_pages_init(parent, &parents, &pages); > >>>> } > >>> Don't see why this is needed? The for_each_sp loop uses pvec.nr. > >> I think mmu_zap_unsync_children() should return the number of zapped pages then we > >> can adjust the number of free pages in kvm_mmu_change_mmu_pages(), but pages.nr no > >> only includes the unsync/zapped pages but also includes their parents. > > > > Oh i see. I think its safer to check for list_empty then to rely on > > proper accounting there, like __kvm_mmu_free_some_pages does. > > Do you mean that we'd better add WARN_ON(list_empty()) code in kvm_mmu_zap_page()? Just break out of the loop if list_empty(&vcpu->kvm->arch.active_mmu_pages). -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |