KVM: x86/mmu: Refactor the zap loop for recovering NX lpages (7d919c7a) · Commits · 戴 / test

Refactor the zap loop in kvm_recover_nx_lpages() to be a for loop that iterates on to_zap and drop the !to_zap check that leads to the in-loop calling of kvm_mmu_commit_zap_page(). The in-loop commit when to_zap hits zero is superfluous now that there's an unconditional commit after the loop to handle the case where lpage_disallowed_mmu_pages is emptied. Signed-off-by:

Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200923183735.584-3-sean.j.christopherson@intel.com> Signed-off-by:

Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/mmu/mmu.c

+6 −4

Original line number	Diff line number	Diff line
		@@ -6375,7 +6375,10 @@ static void kvm_recover_nx_lpages(struct kvm *kvm)

		ratio = READ_ONCE(nx_huge_pages_recovery_ratio);
		to_zap = ratio ? DIV_ROUND_UP(kvm->stat.nx_lpage_splits, ratio) : 0;
		while (to_zap && !list_empty(&kvm->arch.lpage_disallowed_mmu_pages)) {
		for ( ; to_zap; --to_zap) {
		if (list_empty(&kvm->arch.lpage_disallowed_mmu_pages))
		break;

		/*
		* We use a separate list instead of just using active_mmu_pages
		* because the number of lpage_disallowed pages is expected to
		@@ -6388,9 +6391,8 @@ static void kvm_recover_nx_lpages(struct kvm *kvm)
		kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list);
		WARN_ON_ONCE(sp->lpage_disallowed);

		if (!--to_zap \|\| need_resched() \|\| spin_needbreak(&kvm->mmu_lock)) {
		if (need_resched() \|\| spin_needbreak(&kvm->mmu_lock)) {
		kvm_mmu_commit_zap_page(kvm, &invalid_list);
		if (to_zap)
		cond_resched_lock(&kvm->mmu_lock);
		}
		}

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