Commit 3cc4e148 authored by Jing Zhang's avatar Jing Zhang Committed by Paolo Bonzini
Browse files

KVM: stats: Add VM stat for remote tlb flush requests 



Add a new stat that counts the number of times a remote TLB flush is
requested, regardless of whether it kicks vCPUs out of guest mode. This
allows us to look at how often flushes are initiated.

Unlike remote_tlb_flush, this one applies to ARM's instruction-set-based
TLB flush implementation, so apply it there too.

Original-by: default avatarDavid Matlack <dmatlack@google.com>
Signed-off-by: default avatarJing Zhang <jingzhangos@google.com>
Message-Id: <20210817002639.3856694-1-jingzhangos@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent fdde13c1

arch/arm64/kvm/mmu.c

+1 −0
Original line number Diff line number Diff line
@@ -80,6 +80,7 @@ static bool memslot_is_logging(struct kvm_memory_slot *memslot) 
 */

void kvm_flush_remote_tlbs(struct kvm *kvm)

{

	++kvm->stat.generic.remote_tlb_flush_requests;

	kvm_call_hyp(__kvm_tlb_flush_vmid, &kvm->arch.mmu);

}

include/linux/kvm_host.h

+2 −1
Original line number Diff line number Diff line
@@ -1444,7 +1444,8 @@ struct _kvm_stats_desc { 
		KVM_STATS_BASE_POW10, -9, sz)



#define KVM_GENERIC_VM_STATS()						       \

	STATS_DESC_COUNTER(VM_GENERIC, remote_tlb_flush)

	STATS_DESC_COUNTER(VM_GENERIC, remote_tlb_flush),		       \

	STATS_DESC_COUNTER(VM_GENERIC, remote_tlb_flush_requests)



#define KVM_GENERIC_VCPU_STATS()					       \

	STATS_DESC_COUNTER(VCPU_GENERIC, halt_successful_poll),		       \

include/linux/kvm_types.h

+1 −0
Original line number Diff line number Diff line
@@ -80,6 +80,7 @@ struct kvm_mmu_memory_cache { 


struct kvm_vm_stat_generic {

	u64 remote_tlb_flush;

	u64 remote_tlb_flush_requests;

};



struct kvm_vcpu_stat_generic {

virt/kvm/kvm_main.c

+1 −0
Original line number Diff line number Diff line
@@ -318,6 +318,7 @@ void kvm_flush_remote_tlbs(struct kvm *kvm) 
	 */

	long dirty_count = smp_load_acquire(&kvm->tlbs_dirty);



	++kvm->stat.generic.remote_tlb_flush_requests;

	/*

	 * We want to publish modifications to the page tables before reading

	 * mode. Pairs with a memory barrier in arch-specific code.