From 05988d728dcd962d50374e4e63171324163005b6 Mon Sep 17 00:00:00 2001 From: Gleb Natapov Date: Fri, 31 May 2013 08:36:30 +0800 Subject: [PATCH] KVM: MMU: reduce KVM_REQ_MMU_RELOAD when root page is zapped Quote Gleb's mail: | why don't we check for sp->role.invalid in | kvm_mmu_prepare_zap_page before calling kvm_reload_remote_mmus()? and | Actually we can add check for is_obsolete_sp() there too since | kvm_mmu_invalidate_all_pages() already calls kvm_reload_remote_mmus() | after incrementing mmu_valid_gen. [ Xiao: add some comments and the check of is_obsolete_sp() ] Signed-off-by: Gleb Natapov Signed-off-by: Xiao Guangrong Reviewed-by: Marcelo Tosatti Signed-off-by: Gleb Natapov --- arch/x86/kvm/mmu.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 79af88a..6941fa7 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -2108,7 +2108,13 @@ static int kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp, kvm_mod_used_mmu_pages(kvm, -1); } else { list_move(&sp->link, &kvm->arch.active_mmu_pages); - kvm_reload_remote_mmus(kvm); + + /* + * The obsolete pages can not be used on any vcpus. + * See the comments in kvm_mmu_invalidate_zap_all_pages(). + */ + if (!sp->role.invalid && !is_obsolete_sp(kvm, sp)) + kvm_reload_remote_mmus(kvm); } sp->role.invalid = 1; -- 2.7.4