func (p *criStatsProvider) cleanupOutdatedCaches() {
	p.mutex.Lock()
	defer p.mutex.Unlock()

	for k, v := range p.cpuUsageCache {
		if v == nil {
			delete(p.cpuUsageCache, k)
			continue
		}

		if time.Since(time.Unix(0, v.stats.Timestamp)) > defaultCachePeriod {
			delete(p.cpuUsageCache, k)
		}
	}
}

// removeTerminatedPods returns pods with terminated ones removed.

	tests := []struct {
		desc          string
		cpuUsageCache map[string]*cpuUsageRecord
		stats         *runtimeapi.ContainerStats
		expected      *uint64
	}{
		{
			desc:          "should return nil if stats is nil",
			cpuUsageCache: map[string]*cpuUsageRecord{},
		},
		{
			desc:          "should return nil if cpu stats is nil",
			cpuUsageCache: map[string]*cpuUsageRecord{},