sched.stopwait = freezeStopWait
		sched.gcwaiting.Store(true)
		// this should stop running goroutines
		if !preemptall() {
			break // no running goroutines
		}
		usleep(1000)
	}
	// to be sure
	usleep(1000)
	preemptall()
	usleep(1000)
}

// All reads and writes of g's status go through readgstatus, casgstatus
// castogscanstatus, casfrom_Gscanstatus.
//

	if pod.Spec.Priority != nil && IsCriticalPodBasedOnPriority(*pod.Spec.Priority) {
		return true
	}
	return false
}

// Preemptable returns true if preemptor pod can preempt preemptee pod
// if preemptee is not critical or if preemptor's priority is greater than preemptee's priority
func Preemptable(preemptor, preemptee *v1.Pod) bool {
	if IsCriticalPod(preemptor) && !IsCriticalPod(preemptee) {
		return true
	}

			preemptee: getTestPod(configSourceAnnotation(FileSource), &systemPriority, ""),
			expected:  false,
		},
	}
	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			isPreemtable := Preemptable(test.preemptor, test.preemptee)
			assert.Equal(t, test.expected, isPreemtable)
		})
	}
}

func TestIsCriticalPodBasedOnPriority(t *testing.T) {
	tests := []struct {
		priority int32

// can be preempted by preemptor pod.
func sortPodsByQOS(preemptor *v1.Pod, pods []*v1.Pod) (bestEffort, burstable, guaranteed []*v1.Pod) {
	for _, pod := range pods {
		if kubetypes.Preemptable(preemptor, pod) {
			switch v1qos.GetPodQOS(pod) {
			case v1.PodQOSBestEffort:
				bestEffort = append(bestEffort, pod)
			case v1.PodQOSBurstable:
				burstable = append(burstable, pod)