Commit 1328edca authored Aug 29, 2019 by Wanpeng Li Committed by Rafael J. Wysocki Sep 11, 2019

cpuidle-haltpoll: Enable kvm guest polling when dedicated physical CPUs are available



The downside of guest side polling is that polling is performed even
with other runnable tasks in the host. However, even if poll in kvm
can aware whether or not other runnable tasks in the same pCPU, it
can still incur extra overhead in over-subscribe scenario. Now we can
just enable guest polling when dedicated pCPUs are available.

Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

parent 472f2636

arch/x86/kernel/kvm.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -711,6 +711,7 @@ unsigned int kvm_arch_para_hints(void)
		{
		return cpuid_edx(kvm_cpuid_base() \| KVM_CPUID_FEATURES);
		}
		EXPORT_SYMBOL_GPL(kvm_arch_para_hints);

		static uint32_t __init kvm_detect(void)
		{

drivers/cpuidle/cpuidle-haltpoll.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -97,7 +97,8 @@ static int __init haltpoll_init(void)

		cpuidle_poll_state_init(drv);

		if (!kvm_para_available())
		if (!kvm_para_available() \|\|
		!kvm_para_has_hint(KVM_HINTS_REALTIME))
		return -ENODEV;

		ret = cpuidle_register_driver(drv);

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