[PATCH v7 3/4] KVM: x86/mmu: count KVM mmu usage in secondary pagetable stats.

From: Yosry Ahmed <hidden>
Date: 2022-08-23 00:47:09
Also in: cgroups, kvm, kvmarm, linux-mm, lkml
Subsystem: kernel virtual machine for x86 (kvm/x86), the rest, x86 architecture (32-bit and 64-bit) · Maintainers: Sean Christopherson, Paolo Bonzini, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen

Count the pages used by KVM mmu on x86 in memory stats under secondary
pagetable stats (e.g. "SecPageTables" in /proc/meminfo) to give better
visibility into the memory consumption of KVM mmu in a similar way to
how normal user page tables are accounted.

Signed-off-by: Yosry Ahmed <redacted>
Reviewed-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/mmu/mmu.c     | 16 ++++++++++++++--
 arch/x86/kvm/mmu/tdp_mmu.c | 12 ++++++++++++
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index e418ef3ecfcb..4d38e4eba772 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c

@@ -1665,6 +1665,18 @@ static inline void kvm_mod_used_mmu_pages(struct kvm *kvm, long nr)
 	percpu_counter_add(&kvm_total_used_mmu_pages, nr);
 }
 
+static void kvm_account_mmu_page(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+	kvm_mod_used_mmu_pages(kvm, +1);
+	kvm_account_pgtable_pages((void *)sp->spt, +1);
+}
+
+static void kvm_unaccount_mmu_page(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+	kvm_mod_used_mmu_pages(kvm, -1);
+	kvm_account_pgtable_pages((void *)sp->spt, -1);
+}
+
 static void kvm_mmu_free_shadow_page(struct kvm_mmu_page *sp)
 {
 	MMU_WARN_ON(!is_empty_shadow_page(sp->spt));

@@ -2122,7 +2134,7 @@ static struct kvm_mmu_page *kvm_mmu_alloc_shadow_page(struct kvm *kvm,
 	 */
 	sp->mmu_valid_gen = kvm->arch.mmu_valid_gen;
 	list_add(&sp->link, &kvm->arch.active_mmu_pages);
-	kvm_mod_used_mmu_pages(kvm, +1);
+	kvm_account_mmu_page(kvm, sp);
 
 	sp->gfn = gfn;
 	sp->role = role;

@@ -2456,7 +2468,7 @@ static bool __kvm_mmu_prepare_zap_page(struct kvm *kvm,
 			list_add(&sp->link, invalid_list);
 		else
 			list_move(&sp->link, invalid_list);
-		kvm_mod_used_mmu_pages(kvm, -1);
+		kvm_unaccount_mmu_page(kvm, sp);
 	} else {
 		/*
 		 * Remove the active root from the active page list, the root

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index bf2ccf9debca..672f0432d777 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c

@@ -372,6 +372,16 @@ static void handle_changed_spte_dirty_log(struct kvm *kvm, int as_id, gfn_t gfn,
 	}
 }
 
+static void tdp_account_mmu_page(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+	kvm_account_pgtable_pages((void *)sp->spt, +1);
+}
+
+static void tdp_unaccount_mmu_page(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+	kvm_account_pgtable_pages((void *)sp->spt, -1);
+}
+
 /**
  * tdp_mmu_unlink_sp() - Remove a shadow page from the list of used pages
  *

@@ -384,6 +394,7 @@ static void handle_changed_spte_dirty_log(struct kvm *kvm, int as_id, gfn_t gfn,
 static void tdp_mmu_unlink_sp(struct kvm *kvm, struct kvm_mmu_page *sp,
 			      bool shared)
 {
+	tdp_unaccount_mmu_page(kvm, sp);
 	if (shared)
 		spin_lock(&kvm->arch.tdp_mmu_pages_lock);
 	else

@@ -1132,6 +1143,7 @@ static int tdp_mmu_link_sp(struct kvm *kvm, struct tdp_iter *iter,
 	if (account_nx)
 		account_huge_nx_page(kvm, sp);
 	spin_unlock(&kvm->arch.tdp_mmu_pages_lock);
+	tdp_account_mmu_page(kvm, sp);
 
 	return 0;
 }

-- 
2.37.1.595.g718a3a8f04-goog


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