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Commit 5da59607 authored by Takuya Yoshikawa's avatar Takuya Yoshikawa Committed by Marcelo Tosatti
Browse files

KVM: MMU: Introduce a helper function for FIFO zapping 



Make the code for zapping the oldest mmu page, placed at the tail of the
active list, a separate function.

Reviewed-by: default avatarGleb Natapov <gleb@redhat.com>
Signed-off-by: default avatarTakuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent 945315b9

arch/x86/kvm/mmu.c

+23 −32
Original line number Diff line number Diff line
@@ -2110,6 +2110,21 @@ static void kvm_mmu_commit_zap_page(struct kvm *kvm, 
	}

}



static bool prepare_zap_oldest_mmu_page(struct kvm *kvm,

					struct list_head *invalid_list)

{

	struct kvm_mmu_page *sp;



	if (list_empty(&kvm->arch.active_mmu_pages))

		return false;



	sp = list_entry(kvm->arch.active_mmu_pages.prev,

			struct kvm_mmu_page, link);

	kvm_mmu_prepare_zap_page(kvm, sp, invalid_list);



	return true;

}



/*

 * Changing the number of mmu pages allocated to the vm

 * Note: if goal_nr_mmu_pages is too small, you will get dead lock
@@ -2117,23 +2132,15 @@ static void kvm_mmu_commit_zap_page(struct kvm *kvm, 
void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int goal_nr_mmu_pages)

{

	LIST_HEAD(invalid_list);

	/*

	 * If we set the number of mmu pages to be smaller be than the

	 * number of actived pages , we must to free some mmu pages before we

	 * change the value

	 */



	spin_lock(&kvm->mmu_lock);



	if (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages) {

		while (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages &&

			!list_empty(&kvm->arch.active_mmu_pages)) {

			struct kvm_mmu_page *page;

		/* Need to free some mmu pages to achieve the goal. */

		while (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages)

			if (!prepare_zap_oldest_mmu_page(kvm, &invalid_list))

				break;



			page = container_of(kvm->arch.active_mmu_pages.prev,

					    struct kvm_mmu_page, link);

			kvm_mmu_prepare_zap_page(kvm, page, &invalid_list);

		}

		kvm_mmu_commit_zap_page(kvm, &invalid_list);

		goal_nr_mmu_pages = kvm->arch.n_used_mmu_pages;

	}
@@ -4007,13 +4014,10 @@ void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu) 
{

	LIST_HEAD(invalid_list);



	while (kvm_mmu_available_pages(vcpu->kvm) < KVM_REFILL_PAGES &&

	       !list_empty(&vcpu->kvm->arch.active_mmu_pages)) {

		struct kvm_mmu_page *sp;

	while (kvm_mmu_available_pages(vcpu->kvm) < KVM_REFILL_PAGES) {

		if (!prepare_zap_oldest_mmu_page(vcpu->kvm, &invalid_list))

			break;



		sp = container_of(vcpu->kvm->arch.active_mmu_pages.prev,

				  struct kvm_mmu_page, link);

		kvm_mmu_prepare_zap_page(vcpu->kvm, sp, &invalid_list);

		++vcpu->kvm->stat.mmu_recycled;

	}

	kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
@@ -4182,19 +4186,6 @@ void kvm_mmu_zap_all(struct kvm *kvm) 
	spin_unlock(&kvm->mmu_lock);

}



static void kvm_mmu_remove_some_alloc_mmu_pages(struct kvm *kvm,

						struct list_head *invalid_list)

{

	struct kvm_mmu_page *page;



	if (list_empty(&kvm->arch.active_mmu_pages))

		return;



	page = container_of(kvm->arch.active_mmu_pages.prev,

			    struct kvm_mmu_page, link);

	kvm_mmu_prepare_zap_page(kvm, page, invalid_list);

}



static int mmu_shrink(struct shrinker *shrink, struct shrink_control *sc)

{

	struct kvm *kvm;
@@ -4229,7 +4220,7 @@ static int mmu_shrink(struct shrinker *shrink, struct shrink_control *sc) 
		idx = srcu_read_lock(&kvm->srcu);

		spin_lock(&kvm->mmu_lock);



		kvm_mmu_remove_some_alloc_mmu_pages(kvm, &invalid_list);

		prepare_zap_oldest_mmu_page(kvm, &invalid_list);

		kvm_mmu_commit_zap_page(kvm, &invalid_list);



		spin_unlock(&kvm->mmu_lock);