From: Raghavendra K T <raghavendra.kt@xxxxxxxxxxxxxxxxxx>
Noting pause loop exited or cpu relax intercepted vcpu 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@xxxxxxxxxxxxxxxxxx>
---
v2 patches were
Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>
include/linux/kvm_host.h | 12 ++++++++++++
virt/kvm/kvm_main.c | 4 ++++
2 files changed, 16 insertions(+), 0 deletions(-)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index c446435..4ec1cf0 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
+ * cpu_relax_intercepted: 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 cpu_relax_intercepted;
+ bool dy_eligible;
+ } ple;
+#endif
struct kvm_vcpu_arch arch;
};
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 7e14068..4ec0120 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -235,6 +235,8 @@ int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
goto fail;
}
vcpu->run = page_address(page);
+ vcpu->ple.cpu_relax_intercepted = false;
+ vcpu->ple.dy_eligible = false;
r = kvm_arch_vcpu_init(vcpu);
if (r < 0)
@@ -1577,6 +1579,7 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me)
int pass;
int i;
+ me->ple.cpu_relax_intercepted = true;
/*
* We boost the priority of a VCPU that is runnable but not
* currently running, because it got preempted by something
@@ -1602,6 +1605,7 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me)
}
}
}
+ me->ple.cpu_relax_intercepted = false;
}
EXPORT_SYMBOL_GPL(kvm_vcpu_on_spin);
--
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