diff --git a/pkg/core/quota/mclock.go b/pkg/core/quota/mclock.go
index 57e02d202..e6af68577 100644
--- a/pkg/core/quota/mclock.go
+++ b/pkg/core/quota/mclock.go
@@ -12,7 +12,7 @@ const (
 )
 
 type mQueueItem interface {
-	tag() float64
+	ts() float64
 	setIndex(idx int)
 }
 
@@ -21,7 +21,7 @@ type mQueue struct {
 }
 
 type request struct {
-	vm        string
+	tag       string
 	seqNumber uint64
 
 	reservation float64
@@ -33,7 +33,7 @@ type request struct {
 	sharesIdx      int
 }
 
-type vmData struct {
+type tagInfo struct {
 	reservation float64
 	limit       float64
 	shares      float64
@@ -44,14 +44,14 @@ type clock interface {
 }
 
 type worker interface {
-	do(vm string, seqNumber uint64)
+	do(tag string, seqNumber uint64)
 }
 
 type mClockQueue struct {
 	current  uint64
 	limit    uint64
 	clock    clock
-	vmData   map[string]vmData
+	tagInfo  map[string]tagInfo
 	previous map[string]*request
 
 	reservationQueue *mQueue
@@ -62,28 +62,28 @@ type mClockQueue struct {
 	worker worker
 }
 
-func (q *mClockQueue) RequestArrival(vm string) {
+func (q *mClockQueue) RequestArrival(tag string) {
 	now := q.clock.now()
-	vmData, ok := q.vmData[vm]
+	tagInfo, ok := q.tagInfo[tag]
 	if !ok {
-		panic("unknown vm: " + vm)
+		panic("unknown tag: " + tag)
 	}
-	prev, ok := q.previous[vm]
+	prev, ok := q.previous[tag]
 	if !ok {
-		panic("unknown previous: " + vm)
+		panic("undefined previous: " + tag)
 	}
 	r := request{
-		vm:             vm,
-		reservation:    max(prev.reservation+1.0/vmData.reservation, now),
-		limit:          max(prev.limit+1.0/vmData.limit, now),
-		shares:         max(prev.shares+1.0/vmData.shares, now),
+		tag:            tag,
+		reservation:    max(prev.reservation+1.0/tagInfo.reservation, now),
+		limit:          max(prev.limit+1.0/tagInfo.limit, now),
+		shares:         max(prev.shares+1.0/tagInfo.shares, now),
 		seqNumber:      q.index,
 		reservationIdx: invalidIndex,
 		limitIdx:       invalidIndex,
 		sharesIdx:      invalidIndex,
 	}
 	q.index++
-	q.previous[vm] = &r
+	q.previous[tag] = &r
 	heap.Push(q.reservationQueue, &reservationMQueueItem{r: &r})
 	heap.Push(q.limitQueue, &limitMQueueItem{r: &r})
 	q.scheduleRequest()
@@ -91,10 +91,11 @@ func (q *mClockQueue) RequestArrival(vm string) {
 
 func (q *mClockQueue) scheduleRequest() {
 	if q.current >= q.limit {
+		// next request will be scheduled by requestCompleted()
 		return
 	}
 	now := q.clock.now()
-	if q.reservationQueue.Len() > 0 && q.reservationQueue.items[0].tag() <= now {
+	if q.reservationQueue.Len() > 0 && q.reservationQueue.items[0].ts() <= now {
 		it := heap.Pop(q.reservationQueue).(*reservationMQueueItem)
 		if it.r.limitIdx != invalidIndex {
 			heap.Remove(q.limitQueue, it.r.limitIdx)
@@ -104,11 +105,11 @@ func (q *mClockQueue) scheduleRequest() {
 		}
 		assertIndexInvalid(it.r)
 		q.current++
-		q.worker.do(it.r.vm, it.r.seqNumber)
+		q.worker.do(it.r.tag, it.r.seqNumber)
 		return
 	}
 
-	for q.limitQueue.Len() > 0 && q.limitQueue.items[0].tag() <= now {
+	for q.limitQueue.Len() > 0 && q.limitQueue.items[0].ts() <= now {
 		it := heap.Pop(q.limitQueue).(*limitMQueueItem)
 		heap.Push(q.sharesQueue, &sharesMQueueItem{r: it.r})
 	}
@@ -119,14 +120,14 @@ func (q *mClockQueue) scheduleRequest() {
 			heap.Remove(q.reservationQueue, it.r.reservationIdx)
 		}
 		var updated bool
-		vmData, ok := q.vmData[it.r.vm]
+		tagInfo, ok := q.tagInfo[it.r.tag]
 		if !ok {
-			panic("unknown vm: " + it.r.vm)
+			panic("unknown tag: " + it.r.tag)
 		}
 		for _, i := range q.reservationQueue.items {
 			ri := i.(*reservationMQueueItem)
-			if ri.r.vm == it.r.vm {
-				ri.r.reservation -= 1.0 / vmData.reservation
+			if ri.r.tag == it.r.tag {
+				ri.r.reservation -= 1.0 / tagInfo.reservation
 				updated = true
 			}
 		}
@@ -135,7 +136,7 @@ func (q *mClockQueue) scheduleRequest() {
 		}
 		assertIndexInvalid(it.r)
 		q.current++
-		q.worker.do(it.r.vm, it.r.seqNumber)
+		q.worker.do(it.r.tag, it.r.seqNumber)
 		return
 	}
 }
@@ -167,7 +168,7 @@ func (q *mQueue) Len() int {
 
 // Less implements heap.Interface.
 func (q *mQueue) Less(i int, j int) bool {
-	return q.items[i].tag() < q.items[j].tag()
+	return q.items[i].ts() < q.items[j].ts()
 }
 
 // Pop implements heap.Interface.
@@ -198,7 +199,7 @@ type reservationMQueueItem struct {
 	r *request
 }
 
-func (i *reservationMQueueItem) tag() float64 {
+func (i *reservationMQueueItem) ts() float64 {
 	return i.r.reservation
 }
 
diff --git a/pkg/core/quota/mclock_test.go b/pkg/core/quota/mclock_test.go
index effc7b33c..d710f79e3 100644
--- a/pkg/core/quota/mclock_test.go
+++ b/pkg/core/quota/mclock_test.go
@@ -12,7 +12,7 @@ func TestMClockSimulation(t *testing.T) {
 	q := &mClockQueue{
 		limit: 1,
 		clock: &systemClock{},
-		vmData: map[string]vmData{
+		tagInfo: map[string]tagInfo{
 			"class1": {reservation: zeroReservation, limit: maxLimit, shares: 60},
 			"class2": {reservation: zeroReservation, limit: maxLimit, shares: 30},
 		},