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Date: Wed, 18 Jul 2012 19:07:46 +0530 From: Raghavendra K T <raghavendra.kt@...ux.vnet.ibm.com> To: "H. Peter Anvin" <hpa@...or.com>, Thomas Gleixner <tglx@...utronix.de>, Marcelo Tosatti <mtosatti@...hat.com>, Ingo Molnar <mingo@...hat.com>, Avi Kivity <avi@...hat.com>, Rik van Riel <riel@...hat.com> Cc: Srikar <srikar@...ux.vnet.ibm.com>, S390 <linux-s390@...r.kernel.org>, Carsten Otte <cotte@...ibm.com>, Christian Borntraeger <borntraeger@...ibm.com>, KVM <kvm@...r.kernel.org>, Raghavendra K T <raghavendra.kt@...ux.vnet.ibm.com>, chegu vinod <chegu_vinod@...com>, "Andrew M. Theurer" <habanero@...ux.vnet.ibm.com>, LKML <linux-kernel@...r.kernel.org>, X86 <x86@...nel.org>, Gleb Natapov <gleb@...hat.com>, linux390@...ibm.com, Srivatsa Vaddagiri <srivatsa.vaddagiri@...il.com>, Joerg Roedel <joerg.roedel@....com> Subject: [PATCH RFC V5 2/3] kvm: Note down when cpu relax intercepted or pause loop exited From: Raghavendra K T <raghavendra.kt@...ux.vnet.ibm.com> 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@...ux.vnet.ibm.com> --- V2 was: Reviewed-by: Rik van Riel <riel@...hat.com> include/linux/kvm_host.h | 34 ++++++++++++++++++++++++++++++++++ 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 c446435..34ce296 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; }; @@ -890,5 +902,27 @@ 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 7e14068..3d6ffc8 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -236,6 +236,9 @@ 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; @@ -1577,6 +1580,7 @@ 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 @@ -1602,6 +1606,7 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me) } } } + kvm_vcpu_set_in_spin_loop(me, false); } EXPORT_SYMBOL_GPL(kvm_vcpu_on_spin); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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