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| author | Wanpeng Li <wanpengli@tencent.com> | 2019-08-29 16:49:57 +0800 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2019-09-11 17:46:15 +0200 |
| commit | 1328edca4a142ee3c7442d1eece2c3ca383eff35 (patch) | |
| tree | 75a50d1d56f31a075fe7d1372a247f654a57a46d | |
| parent | 472f263660832b90e53bede2020f68cd14f8b76c (diff) | |
| download | linux-1328edca4a142ee3c7442d1eece2c3ca383eff35.tar.gz linux-1328edca4a142ee3c7442d1eece2c3ca383eff35.tar.bz2 linux-1328edca4a142ee3c7442d1eece2c3ca383eff35.zip | |
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>
| -rw-r--r-- | arch/x86/kernel/kvm.c | 1 | ||||
| -rw-r--r-- | drivers/cpuidle/cpuidle-haltpoll.c | 3 |
2 files changed, 3 insertions, 1 deletions
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 60bab4a3b36b..3726ba48f763 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -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) { diff --git a/drivers/cpuidle/cpuidle-haltpoll.c b/drivers/cpuidle/cpuidle-haltpoll.c index 49a65c6fe91e..932390b028f1 100644 --- a/drivers/cpuidle/cpuidle-haltpoll.c +++ b/drivers/cpuidle/cpuidle-haltpoll.c @@ -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); |