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| author | David Matlack <dmatlack@google.com> | 2016-12-21 02:25:57 +0300 |
|---|---|---|
| committer | Radim Krčmář <rkrcmar@redhat.com> | 2017-01-09 16:46:03 +0300 |
| commit | f3414bc77419463c0d81eaa2cea7ee4ccb447c7d (patch) | |
| tree | 153185d45ad2105c030648945e650687fe3adfec /arch/x86/kvm/mmu.c | |
| parent | 826da32140dada1467f4216410525511393317e8 (diff) | |
| download | linux-f3414bc77419463c0d81eaa2cea7ee4ccb447c7d.tar.xz | |
kvm: x86: export maximum number of mmu_page_hash collisions
Report the maximum number of mmu_page_hash collisions as a per-VM stat.
This will make it easy to identify problems with the mmu_page_hash in
the future.
Signed-off-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/mmu.c')
| -rw-r--r-- | arch/x86/kvm/mmu.c | 25 |
1 files changed, 17 insertions, 8 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 7012de4a1fed..45ee7ae88239 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -1904,17 +1904,17 @@ static void kvm_mmu_commit_zap_page(struct kvm *kvm, * since it has been deleted from active_mmu_pages but still can be found * at hast list. * - * for_each_gfn_valid_sp() has skipped that kind of pages. + * for_each_valid_sp() has skipped that kind of pages. */ -#define for_each_gfn_valid_sp(_kvm, _sp, _gfn) \ +#define for_each_valid_sp(_kvm, _sp, _gfn) \ hlist_for_each_entry(_sp, \ &(_kvm)->arch.mmu_page_hash[kvm_page_table_hashfn(_gfn)], hash_link) \ - if ((_sp)->gfn != (_gfn) || is_obsolete_sp((_kvm), (_sp)) \ - || (_sp)->role.invalid) {} else + if (is_obsolete_sp((_kvm), (_sp)) || (_sp)->role.invalid) { \ + } else #define for_each_gfn_indirect_valid_sp(_kvm, _sp, _gfn) \ - for_each_gfn_valid_sp(_kvm, _sp, _gfn) \ - if ((_sp)->role.direct) {} else + for_each_valid_sp(_kvm, _sp, _gfn) \ + if ((_sp)->gfn != (_gfn) || (_sp)->role.direct) {} else /* @sp->gfn should be write-protected at the call site */ static bool __kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, @@ -2116,6 +2116,7 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp; bool need_sync = false; bool flush = false; + int collisions = 0; LIST_HEAD(invalid_list); role = vcpu->arch.mmu.base_role; @@ -2130,7 +2131,12 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1; role.quadrant = quadrant; } - for_each_gfn_valid_sp(vcpu->kvm, sp, gfn) { + for_each_valid_sp(vcpu->kvm, sp, gfn) { + if (sp->gfn != gfn) { + collisions++; + continue; + } + if (!need_sync && sp->unsync) need_sync = true; @@ -2153,7 +2159,7 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, __clear_sp_write_flooding_count(sp); trace_kvm_mmu_get_page(sp, false); - return sp; + goto out; } ++vcpu->kvm->stat.mmu_cache_miss; @@ -2183,6 +2189,9 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, trace_kvm_mmu_get_page(sp, true); kvm_mmu_flush_or_zap(vcpu, &invalid_list, false, flush); +out: + if (collisions > vcpu->kvm->stat.max_mmu_page_hash_collisions) + vcpu->kvm->stat.max_mmu_page_hash_collisions = collisions; return sp; } |