static void shrink_halt_poll_ns(struct kvm_vcpu *vcpu)
{
	unsigned int old, val, shrink;

	old = val = vcpu->halt_poll_ns;
	shrink = READ_ONCE(halt_poll_ns_shrink);
	if (shrink == 0)
		val = 0;
	else
		val /= shrink;

	vcpu->halt_poll_ns = val;
	trace_kvm_halt_poll_ns_shrink(vcpu->vcpu_id, val, old);
}