diff --git a/pkg/disttask/framework/taskexecutor/manager.go b/pkg/disttask/framework/taskexecutor/manager.go
index 7f864e9c7b5e1..48fb9ad321a34 100644
--- a/pkg/disttask/framework/taskexecutor/manager.go
+++ b/pkg/disttask/framework/taskexecutor/manager.go
@@ -94,7 +94,7 @@ func (b *ManagerBuilder) BuildManager(ctx context.Context, id string, taskTable
 		logCtx:    logutil.WithFields(context.Background()),
 		newPool:   b.newPool,
 		slotManager: &slotManager{
-			executorSlotInfos: make(map[int64]*slotInfo, 0),
+			executorSlotInfos: make(map[int64]*slotInfo),
 			available:         cpu.GetCPUCount(),
 		},
 	}
@@ -222,7 +222,7 @@ func (m *Manager) onRunnableTasks(tasks []*proto.Task) {
 		}
 		logutil.Logger(m.logCtx).Info("detect new subtask", zap.Int64("task-id", task.ID))
 
-		if !m.slotManager.canReserve(task) {
+		if !m.slotManager.canAlloc(task) {
 			failpoint.Inject("taskTick", func() {
 				<-onRunnableTasksTick
 			})
@@ -231,14 +231,13 @@ func (m *Manager) onRunnableTasks(tasks []*proto.Task) {
 		m.addHandlingTask(task.ID)
 		t := task
 		err = m.executorPool.Run(func() {
-			m.slotManager.reserve(t)
-			defer m.slotManager.unReserve(t.ID)
+			m.slotManager.alloc(t)
+			defer m.slotManager.free(t.ID)
 			m.onRunnableTask(t)
 			m.removeHandlingTask(t.ID)
 		})
 		// pool closed.
 		if err != nil {
-			m.slotManager.unReserve(t.ID)
 			m.removeHandlingTask(task.ID)
 			m.logErr(err)
 			return
diff --git a/pkg/disttask/framework/taskexecutor/slot.go b/pkg/disttask/framework/taskexecutor/slot.go
index cb9a34ef606c2..e788312fbccc3 100644
--- a/pkg/disttask/framework/taskexecutor/slot.go
+++ b/pkg/disttask/framework/taskexecutor/slot.go
@@ -38,7 +38,7 @@ type slotInfo struct {
 	slotCount int
 }
 
-func (sm *slotManager) reserve(task *proto.Task) {
+func (sm *slotManager) alloc(task *proto.Task) {
 	sm.Lock()
 	defer sm.Unlock()
 	sm.executorSlotInfos[task.ID] = &slotInfo{
@@ -50,7 +50,7 @@ func (sm *slotManager) reserve(task *proto.Task) {
 	sm.available -= task.Concurrency
 }
 
-func (sm *slotManager) unReserve(taskID int64) {
+func (sm *slotManager) free(taskID int64) {
 	sm.Lock()
 	defer sm.Unlock()
 
@@ -62,9 +62,9 @@ func (sm *slotManager) unReserve(taskID int64) {
 }
 
 // canReserve is used to check whether the instance has enough slots to run the task.
-func (sm *slotManager) canReserve(task *proto.Task) bool {
-	sm.Lock()
-	defer sm.Unlock()
+func (sm *slotManager) canAlloc(task *proto.Task) bool {
+	sm.RLock()
+	defer sm.RUnlock()
 
 	return sm.available >= task.Concurrency
 }
diff --git a/pkg/disttask/framework/taskexecutor/slot_test.go b/pkg/disttask/framework/taskexecutor/slot_test.go
index 8b18c8dce8558..65fff426b9f04 100644
--- a/pkg/disttask/framework/taskexecutor/slot_test.go
+++ b/pkg/disttask/framework/taskexecutor/slot_test.go
@@ -38,18 +38,18 @@ func TestSlotManager(t *testing.T) {
 		Priority:    1,
 		Concurrency: 1,
 	}
-	require.True(t, sm.canReserve(task))
-	sm.reserve(task)
+	require.True(t, sm.canAlloc(task))
+	sm.alloc(task)
 	require.Equal(t, 1, sm.executorSlotInfos[taskID].priority)
 	require.Equal(t, 1, sm.executorSlotInfos[taskID].slotCount)
 	require.Equal(t, 9, sm.available)
 
-	require.False(t, sm.canReserve(&proto.Task{
+	require.False(t, sm.canAlloc(&proto.Task{
 		ID:          taskID2,
 		Priority:    2,
 		Concurrency: 10,
 	}))
 
-	sm.unReserve(taskID)
+	sm.free(taskID)
 	require.Nil(t, sm.executorSlotInfos[taskID])
 }