| Message ID | 20231009093304.2555344-2-nrb@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: s390: add counters for vsie performance | expand |
On Mon, 9 Oct 2023 11:32:52 +0200 Nico Boehr <nrb@linux.ibm.com> wrote: > The shadow gmap tracks memory of nested guests (guest-3). In certain > scenarios, the shadow gmap needs to be rebuilt, which is a costly operation > since it involves a SIE exit into guest-1 for every entry in the respective > shadow level. > > Add kvm stat counters when new shadow structures are created at various > levels. Also add a counter gmap_shadow_create when a completely fresh > shadow gmap is created as well as a counter gmap_shadow_reuse when an > existing gmap is being reused. > > Note that when several levels are shadowed at once, counters on all > affected levels will be increased. > > Also note that not all page table levels need to be present and a ASCE > can directly point to e.g. a segment table. In this case, a new segment > table will always be equivalent to a new shadow gmap and hence will be > counted as gmap_shadow_create and not as gmap_shadow_segment. > > Signed-off-by: Nico Boehr <nrb@linux.ibm.com> > Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> > --- > arch/s390/include/asm/kvm_host.h | 7 +++++++ > arch/s390/kvm/gaccess.c | 7 +++++++ > arch/s390/kvm/kvm-s390.c | 9 ++++++++- > arch/s390/kvm/vsie.c | 5 ++++- > 4 files changed, 26 insertions(+), 2 deletions(-) > > diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h > index 427f9528a7b6..67a298b6cf6e 100644 > --- a/arch/s390/include/asm/kvm_host.h > +++ b/arch/s390/include/asm/kvm_host.h > @@ -777,6 +777,13 @@ struct kvm_vm_stat { > u64 inject_service_signal; > u64 inject_virtio; > u64 aen_forward; > + u64 gmap_shadow_create; > + u64 gmap_shadow_reuse; > + u64 gmap_shadow_r1_entry; > + u64 gmap_shadow_r2_entry; > + u64 gmap_shadow_r3_entry; > + u64 gmap_shadow_sg_entry; > + u64 gmap_shadow_pg_entry; > }; > > struct kvm_arch_memory_slot { > diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c > index 6d6bc19b37dc..ff8349d17b33 100644 > --- a/arch/s390/kvm/gaccess.c > +++ b/arch/s390/kvm/gaccess.c > @@ -1382,6 +1382,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, > unsigned long *pgt, int *dat_protection, > int *fake) > { > + struct kvm *kvm; > struct gmap *parent; > union asce asce; > union vaddress vaddr; > @@ -1390,6 +1391,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, > > *fake = 0; > *dat_protection = 0; > + kvm = sg->private; > parent = sg->parent; > vaddr.addr = saddr; > asce.val = sg->orig_asce; > @@ -1450,6 +1452,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, > rc = gmap_shadow_r2t(sg, saddr, rfte.val, *fake); > if (rc) > return rc; > + kvm->stat.gmap_shadow_r1_entry++; > } > fallthrough; > case ASCE_TYPE_REGION2: { > @@ -1478,6 +1481,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, > rc = gmap_shadow_r3t(sg, saddr, rste.val, *fake); > if (rc) > return rc; > + kvm->stat.gmap_shadow_r2_entry++; > } > fallthrough; > case ASCE_TYPE_REGION3: { > @@ -1515,6 +1519,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, > rc = gmap_shadow_sgt(sg, saddr, rtte.val, *fake); > if (rc) > return rc; > + kvm->stat.gmap_shadow_r3_entry++; > } > fallthrough; > case ASCE_TYPE_SEGMENT: { > @@ -1548,6 +1553,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, > rc = gmap_shadow_pgt(sg, saddr, ste.val, *fake); > if (rc) > return rc; > + kvm->stat.gmap_shadow_sg_entry++; > } > } > /* Return the parent address of the page table */ > @@ -1618,6 +1624,7 @@ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg, > pte.p |= dat_protection; > if (!rc) > rc = gmap_shadow_page(sg, saddr, __pte(pte.val)); > + vcpu->kvm->stat.gmap_shadow_pg_entry++; > ipte_unlock(vcpu->kvm); > mmap_read_unlock(sg->mm); > return rc; > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > index b3f17e014cab..b42493110d76 100644 > --- a/arch/s390/kvm/kvm-s390.c > +++ b/arch/s390/kvm/kvm-s390.c > @@ -66,7 +66,14 @@ const struct _kvm_stats_desc kvm_vm_stats_desc[] = { > STATS_DESC_COUNTER(VM, inject_pfault_done), > STATS_DESC_COUNTER(VM, inject_service_signal), > STATS_DESC_COUNTER(VM, inject_virtio), > - STATS_DESC_COUNTER(VM, aen_forward) > + STATS_DESC_COUNTER(VM, aen_forward), > + STATS_DESC_COUNTER(VM, gmap_shadow_reuse), > + STATS_DESC_COUNTER(VM, gmap_shadow_create), > + STATS_DESC_COUNTER(VM, gmap_shadow_r1_entry), > + STATS_DESC_COUNTER(VM, gmap_shadow_r2_entry), > + STATS_DESC_COUNTER(VM, gmap_shadow_r3_entry), > + STATS_DESC_COUNTER(VM, gmap_shadow_sg_entry), > + STATS_DESC_COUNTER(VM, gmap_shadow_pg_entry), > }; > > const struct kvm_stats_header kvm_vm_stats_header = { > diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c > index 61499293c2ac..02dcbe82a8e5 100644 > --- a/arch/s390/kvm/vsie.c > +++ b/arch/s390/kvm/vsie.c > @@ -1214,8 +1214,10 @@ static int acquire_gmap_shadow(struct kvm_vcpu *vcpu, > * we're holding has been unshadowed. If the gmap is still valid, > * we can safely reuse it. > */ > - if (vsie_page->gmap && gmap_shadow_valid(vsie_page->gmap, asce, edat)) > + if (vsie_page->gmap && gmap_shadow_valid(vsie_page->gmap, asce, edat)) { > + vcpu->kvm->stat.gmap_shadow_reuse++; > return 0; > + } > > /* release the old shadow - if any, and mark the prefix as unmapped */ > release_gmap_shadow(vsie_page); > @@ -1223,6 +1225,7 @@ static int acquire_gmap_shadow(struct kvm_vcpu *vcpu, > if (IS_ERR(gmap)) > return PTR_ERR(gmap); > gmap->private = vcpu->kvm; > + vcpu->kvm->stat.gmap_shadow_create++; > WRITE_ONCE(vsie_page->gmap, gmap); > return 0; > }
On 10/9/23 11:32, Nico Boehr wrote: > The shadow gmap tracks memory of nested guests (guest-3). In certain > scenarios, the shadow gmap needs to be rebuilt, which is a costly operation > since it involves a SIE exit into guest-1 for every entry in the respective > shadow level. > > Add kvm stat counters when new shadow structures are created at various > levels. Also add a counter gmap_shadow_create when a completely fresh > shadow gmap is created as well as a counter gmap_shadow_reuse when an > existing gmap is being reused. > > Note that when several levels are shadowed at once, counters on all > affected levels will be increased. > > Also note that not all page table levels need to be present and a ASCE > can directly point to e.g. a segment table. In this case, a new segment > table will always be equivalent to a new shadow gmap and hence will be > counted as gmap_shadow_create and not as gmap_shadow_segment. > > Signed-off-by: Nico Boehr <nrb@linux.ibm.com> > Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index 427f9528a7b6..67a298b6cf6e 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -777,6 +777,13 @@ struct kvm_vm_stat { u64 inject_service_signal; u64 inject_virtio; u64 aen_forward; + u64 gmap_shadow_create; + u64 gmap_shadow_reuse; + u64 gmap_shadow_r1_entry; + u64 gmap_shadow_r2_entry; + u64 gmap_shadow_r3_entry; + u64 gmap_shadow_sg_entry; + u64 gmap_shadow_pg_entry; }; struct kvm_arch_memory_slot { diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c index 6d6bc19b37dc..ff8349d17b33 100644 --- a/arch/s390/kvm/gaccess.c +++ b/arch/s390/kvm/gaccess.c @@ -1382,6 +1382,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, unsigned long *pgt, int *dat_protection, int *fake) { + struct kvm *kvm; struct gmap *parent; union asce asce; union vaddress vaddr; @@ -1390,6 +1391,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, *fake = 0; *dat_protection = 0; + kvm = sg->private; parent = sg->parent; vaddr.addr = saddr; asce.val = sg->orig_asce; @@ -1450,6 +1452,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, rc = gmap_shadow_r2t(sg, saddr, rfte.val, *fake); if (rc) return rc; + kvm->stat.gmap_shadow_r1_entry++; } fallthrough; case ASCE_TYPE_REGION2: { @@ -1478,6 +1481,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, rc = gmap_shadow_r3t(sg, saddr, rste.val, *fake); if (rc) return rc; + kvm->stat.gmap_shadow_r2_entry++; } fallthrough; case ASCE_TYPE_REGION3: { @@ -1515,6 +1519,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, rc = gmap_shadow_sgt(sg, saddr, rtte.val, *fake); if (rc) return rc; + kvm->stat.gmap_shadow_r3_entry++; } fallthrough; case ASCE_TYPE_SEGMENT: { @@ -1548,6 +1553,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, rc = gmap_shadow_pgt(sg, saddr, ste.val, *fake); if (rc) return rc; + kvm->stat.gmap_shadow_sg_entry++; } } /* Return the parent address of the page table */ @@ -1618,6 +1624,7 @@ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg, pte.p |= dat_protection; if (!rc) rc = gmap_shadow_page(sg, saddr, __pte(pte.val)); + vcpu->kvm->stat.gmap_shadow_pg_entry++; ipte_unlock(vcpu->kvm); mmap_read_unlock(sg->mm); return rc; diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index b3f17e014cab..b42493110d76 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -66,7 +66,14 @@ const struct _kvm_stats_desc kvm_vm_stats_desc[] = { STATS_DESC_COUNTER(VM, inject_pfault_done), STATS_DESC_COUNTER(VM, inject_service_signal), STATS_DESC_COUNTER(VM, inject_virtio), - STATS_DESC_COUNTER(VM, aen_forward) + STATS_DESC_COUNTER(VM, aen_forward), + STATS_DESC_COUNTER(VM, gmap_shadow_reuse), + STATS_DESC_COUNTER(VM, gmap_shadow_create), + STATS_DESC_COUNTER(VM, gmap_shadow_r1_entry), + STATS_DESC_COUNTER(VM, gmap_shadow_r2_entry), + STATS_DESC_COUNTER(VM, gmap_shadow_r3_entry), + STATS_DESC_COUNTER(VM, gmap_shadow_sg_entry), + STATS_DESC_COUNTER(VM, gmap_shadow_pg_entry), }; const struct kvm_stats_header kvm_vm_stats_header = { diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c index 61499293c2ac..02dcbe82a8e5 100644 --- a/arch/s390/kvm/vsie.c +++ b/arch/s390/kvm/vsie.c @@ -1214,8 +1214,10 @@ static int acquire_gmap_shadow(struct kvm_vcpu *vcpu, * we're holding has been unshadowed. If the gmap is still valid, * we can safely reuse it. */ - if (vsie_page->gmap && gmap_shadow_valid(vsie_page->gmap, asce, edat)) + if (vsie_page->gmap && gmap_shadow_valid(vsie_page->gmap, asce, edat)) { + vcpu->kvm->stat.gmap_shadow_reuse++; return 0; + } /* release the old shadow - if any, and mark the prefix as unmapped */ release_gmap_shadow(vsie_page); @@ -1223,6 +1225,7 @@ static int acquire_gmap_shadow(struct kvm_vcpu *vcpu, if (IS_ERR(gmap)) return PTR_ERR(gmap); gmap->private = vcpu->kvm; + vcpu->kvm->stat.gmap_shadow_create++; WRITE_ONCE(vsie_page->gmap, gmap); return 0; }