From 5da596078f915a62e39a20e582308eab91b88c9a Mon Sep 17 00:00:00 2001 From: Takuya Yoshikawa Date: Wed, 6 Mar 2013 16:06:58 +0900 Subject: [PATCH] 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: Gleb Natapov Signed-off-by: Takuya Yoshikawa Signed-off-by: Marcelo Tosatti --- arch/x86/kvm/mmu.c | 55 +++++++++++++++++++--------------------------- 1 file changed, 23 insertions(+), 32 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 0f42645a063c..fdacabba6f62 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -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 @@ restart: 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);