KVM: MMU: lower the aduit frequency

The audit is very high overhead, so we need lower the frequency to assure
the guest is running.

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/arch/x86/kvm/mmu_audit.c b/arch/x86/kvm/mmu_audit.c
index 3bde186..bd2b1be 100644 (file)
--- a/arch/x86/kvm/mmu_audit.c
+++ b/arch/x86/kvm/mmu_audit.c
@@ -17,6 +17,8 @@
  *
  */
 
+#include <linux/ratelimit.h>
+
 static const char *audit_msg;
 
 typedef void (*inspect_spte_fn) (struct kvm_vcpu *vcpu, u64 *sptep, int level);
@@ -228,6 +230,11 @@ static void audit_vcpu_spte(struct kvm_vcpu *vcpu)
 
 static void kvm_mmu_audit(void *ignore, struct kvm_vcpu *vcpu, int audit_point)
 {
+       static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
+
+       if (!__ratelimit(&ratelimit_state))
+               return;
+
        audit_msg = audit_point_name[audit_point];
        audit_all_active_sps(vcpu->kvm);
        audit_vcpu_spte(vcpu);