[RFC,3/9] replace x86 kvm n_free_mmu_pages with n_used_mmu_pages

Commit Message

David Hansen June 15, 2010, 1:55 p.m. UTC

None

Patch

diff -puN arch/x86/include/asm/kvm_host.h~replace-free-with-used arch/x86/include/asm/kvm_host.h
--- linux-2.6.git/arch/x86/include/asm/kvm_host.h~replace-free-with-used	2010-06-09 15:14:29.000000000 -0700
+++ linux-2.6.git-dave/arch/x86/include/asm/kvm_host.h	2010-06-09 15:14:29.000000000 -0700
@@ -380,7 +380,7 @@  struct kvm_mem_aliases {
 struct kvm_arch {
 	struct kvm_mem_aliases *aliases;
 
-	unsigned int n_free_mmu_pages;
+	unsigned int n_used_mmu_pages;
 	unsigned int n_requested_mmu_pages;
 	unsigned int n_max_mmu_pages;
 	atomic_t invlpg_counter;
diff -puN arch/x86/kvm/mmu.c~replace-free-with-used arch/x86/kvm/mmu.c
--- linux-2.6.git/arch/x86/kvm/mmu.c~replace-free-with-used	2010-06-09 15:14:29.000000000 -0700
+++ linux-2.6.git-dave/arch/x86/kvm/mmu.c	2010-06-09 15:14:29.000000000 -0700
@@ -898,7 +898,7 @@  static void kvm_mmu_free_page(struct kvm
 	__free_page(virt_to_page(sp->spt));
 	__free_page(virt_to_page(sp->gfns));
 	kfree(sp);
-	++kvm->arch.n_free_mmu_pages;
+	--kvm->arch.n_used_mmu_pages;
 }
 
 static unsigned kvm_page_table_hashfn(gfn_t gfn)
@@ -919,7 +919,7 @@  static struct kvm_mmu_page *kvm_mmu_allo
 	bitmap_zero(sp->slot_bitmap, KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS);
 	sp->multimapped = 0;
 	sp->parent_pte = parent_pte;
-	--vcpu->kvm->arch.n_free_mmu_pages;
+	++vcpu->kvm->arch.n_used_mmu_pages;
 	return sp;
 }
 
@@ -1516,39 +1516,30 @@  static int kvm_mmu_zap_page(struct kvm *
 
 /*
  * Changing the number of mmu pages allocated to the vm
- * Note: if kvm_nr_mmu_pages is too small, you will get dead lock
+ * Note: if goal_nr_mmu_pages is too small, you will get dead lock
  */
-void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages)
+void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int goal_nr_mmu_pages)
 {
-	int used_pages;
-
-	used_pages = kvm->arch.n_max_mmu_pages - kvm_mmu_available_pages(kvm);
-	used_pages = max(0, used_pages);
-
 	/*
 	 * 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
 	 */
 
-	if (used_pages > kvm_nr_mmu_pages) {
-		while (used_pages > kvm_nr_mmu_pages &&
+	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;
 
 			page = container_of(kvm->arch.active_mmu_pages.prev,
 					    struct kvm_mmu_page, link);
-			used_pages -= kvm_mmu_zap_page(kvm, page);
-			used_pages--;
+			kvm->arch.n_used_mmu_pages -= kvm_mmu_zap_page(kvm, page);
+			kvm->arch.n_used_mmu_pages--;
 		}
-		kvm_nr_mmu_pages = used_pages;
-		kvm->arch.n_free_mmu_pages = 0;
+		goal_nr_mmu_pages = kvm->arch.n_used_mmu_pages;
 	}
-	else
-		kvm->arch.n_free_mmu_pages += kvm_nr_mmu_pages
-					 - kvm->arch.n_max_mmu_pages;
 
-	kvm->arch.n_max_mmu_pages = kvm_nr_mmu_pages;
+	kvm->arch.n_max_mmu_pages = goal_nr_mmu_pages;
 }
 
 static int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
diff -puN arch/x86/kvm/mmu.h~replace-free-with-used arch/x86/kvm/mmu.h
--- linux-2.6.git/arch/x86/kvm/mmu.h~replace-free-with-used	2010-06-09 15:14:29.000000000 -0700
+++ linux-2.6.git-dave/arch/x86/kvm/mmu.h	2010-06-09 15:14:29.000000000 -0700
@@ -52,7 +52,8 @@  int kvm_mmu_get_spte_hierarchy(struct kv
 
 static inline unsigned int kvm_mmu_available_pages(struct kvm *kvm)
 {
-	return kvm->arch.n_free_mmu_pages;
+	return kvm->arch.n_max_mmu_pages -
+		kvm->arch.n_used_mmu_pages;
 }
 
 static inline void kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)