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| author | Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> | 2012-07-18 19:07:46 +0530 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2012-07-23 13:01:52 +0300 |
| commit | 4c088493c8d07e4e27bad53a99dcfdc14cdf45f8 (patch) | |
| tree | b90cfa07e207bb938b6997ae62c774c0624b0dd6 | |
| parent | f2a743473194a1ad44a85f8b63aeef9d63e5bf47 (diff) | |
| download | linux-stable-4c088493c8d07e4e27bad53a99dcfdc14cdf45f8.tar.gz linux-stable-4c088493c8d07e4e27bad53a99dcfdc14cdf45f8.tar.bz2 linux-stable-4c088493c8d07e4e27bad53a99dcfdc14cdf45f8.zip | |
KVM: Note down when cpu relax intercepted or pause loop exited
Noting pause loop exited vcpu or cpu relax intercepted helps in
filtering right candidate to yield. Wrong selection of vcpu;
i.e., a vcpu that just did a pl-exit or cpu relax intercepted may
contribute to performance degradation.
Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> # on s390x
Signed-off-by: Avi Kivity <avi@redhat.com>
| -rw-r--r-- | include/linux/kvm_host.h | 34 | ||||
| -rw-r--r-- | virt/kvm/kvm_main.c | 5 |
2 files changed, 39 insertions, 0 deletions
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index db9aa917840a..361b36fe7ecc 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -183,6 +183,18 @@ struct kvm_vcpu { } async_pf; #endif +#ifdef CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT + /* + * Cpu relax intercept or pause loop exit optimization + * in_spin_loop: set when a vcpu does a pause loop exit + * or cpu relax intercepted. + * dy_eligible: indicates whether vcpu is eligible for directed yield. + */ + struct { + bool in_spin_loop; + bool dy_eligible; + } spin_loop; +#endif struct kvm_vcpu_arch arch; }; @@ -898,5 +910,27 @@ static inline bool kvm_check_request(int req, struct kvm_vcpu *vcpu) } } +#ifdef CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT + +static inline void kvm_vcpu_set_in_spin_loop(struct kvm_vcpu *vcpu, bool val) +{ + vcpu->spin_loop.in_spin_loop = val; +} +static inline void kvm_vcpu_set_dy_eligible(struct kvm_vcpu *vcpu, bool val) +{ + vcpu->spin_loop.dy_eligible = val; +} + +#else /* !CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT */ + +static inline void kvm_vcpu_set_in_spin_loop(struct kvm_vcpu *vcpu, bool val) +{ +} + +static inline void kvm_vcpu_set_dy_eligible(struct kvm_vcpu *vcpu, bool val) +{ +} + +#endif /* CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT */ #endif diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 68dda513cd72..0892b75eeedd 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -239,6 +239,9 @@ int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id) } vcpu->run = page_address(page); + kvm_vcpu_set_in_spin_loop(vcpu, false); + kvm_vcpu_set_dy_eligible(vcpu, false); + r = kvm_arch_vcpu_init(vcpu); if (r < 0) goto fail_free_run; @@ -1585,6 +1588,7 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me) int pass; int i; + kvm_vcpu_set_in_spin_loop(me, true); /* * We boost the priority of a VCPU that is runnable but not * currently running, because it got preempted by something @@ -1610,6 +1614,7 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me) } } } + kvm_vcpu_set_in_spin_loop(me, false); } EXPORT_SYMBOL_GPL(kvm_vcpu_on_spin); |