From: Marcelo Tosatti Date: Wed, 8 Apr 2015 20:33:25 -0300 Subject: KVM: lapic: mark LAPIC timer handler as irqsafe Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.4/patches-4.4.1-rt6.tar.xz Since lapic timer handler only wakes up a simple waitqueue, it can be executed from hardirq context. Reduces average cyclictest latency by 3us. Signed-off-by: Marcelo Tosatti Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/kvm/lapic.c | 1 + 1 file changed, 1 insertion(+) --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -1801,6 +1801,7 @@ int kvm_create_lapic(struct kvm_vcpu *vc hrtimer_init(&apic->lapic_timer.timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); apic->lapic_timer.timer.function = apic_timer_fn; + apic->lapic_timer.timer.irqsafe = 1; /* * APIC is created enabled. This will prevent kvm_lapic_set_base from