chore: cleanup inFlightPods when closing the queue

pkg/scheduler/backend/queue/active_queue.go

@@ -381,6 +381,12 @@ func (aq *activeQueue) done(pod types.UID) {
 
 // close closes the activeQueue.
 func (aq *activeQueue) close() {
+	// We should call done() for all in-flight pods to clean up the inFlightEvents metrics.
+	// It's safe even if the binding cycle running asynchronously calls done() afterwards
+	// done() will just be a no-op.
+	for pod := range aq.inFlightPods {
+		aq.done(pod)
+	}
 	aq.lock.Lock()
 	aq.closed = true
 	aq.lock.Unlock()

pkg/scheduler/backend/queue/active_queue_test.go

@@ -0,0 +1,69 @@
+/*
+Copyright 2024 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package queue
+
+import (
+	"testing"
+	"time"
+
+	"k8s.io/klog/v2/ktesting"
+	"k8s.io/kubernetes/pkg/scheduler/backend/heap"
+	"k8s.io/kubernetes/pkg/scheduler/framework"
+	"k8s.io/kubernetes/pkg/scheduler/metrics"
+	st "k8s.io/kubernetes/pkg/scheduler/testing"
+)
+
+func TestClose(t *testing.T) {
+	logger, ctx := ktesting.NewTestContext(t)
+	rr := metrics.NewMetricsAsyncRecorder(10, time.Second, ctx.Done())
+	aq := newActiveQueue(heap.NewWithRecorder(podInfoKeyFunc, heap.LessFunc[*framework.QueuedPodInfo](newDefaultQueueSort()), metrics.NewActivePodsRecorder()), true, *rr)
+
+	aq.underLock(func(unlockedActiveQ unlockedActiveQueuer) {
+		unlockedActiveQ.AddOrUpdate(&framework.QueuedPodInfo{PodInfo: &framework.PodInfo{Pod: st.MakePod().Namespace("foo").Name("p1").UID("p1").Obj()}})
+		unlockedActiveQ.AddOrUpdate(&framework.QueuedPodInfo{PodInfo: &framework.PodInfo{Pod: st.MakePod().Namespace("bar").Name("p2").UID("p2").Obj()}})
+	})
+
+	_, err := aq.pop(logger)
+	if err != nil {
+		t.Fatalf("unexpected error while pop(): %v", err)
+	}
+	_, err = aq.pop(logger)
+	if err != nil {
+		t.Fatalf("unexpected error while pop(): %v", err)
+	}
+	aq.addEventIfAnyInFlight(nil, nil, framework.NodeAdd)
+	aq.addEventIfAnyInFlight(nil, nil, framework.NodeConditionChange)
+
+	if len(aq.listInFlightEvents()) != 4 {
+		t.Fatalf("unexpected number of in-flight events: %v", len(aq.listInFlightEvents()))
+	}
+	if len(aq.listInFlightPods()) != 2 {
+		t.Fatalf("unexpected number of in-flight pods: %v", len(aq.listInFlightPods()))
+	}
+
+	aq.close()
+
+	// make sure the in-flight events and pods are cleaned up by close()
+
+	if len(aq.listInFlightEvents()) != 0 {
+		t.Fatalf("in-flight events should be cleaned up, but %v item(s) is remaining", len(aq.listInFlightEvents()))
+	}
+
+	if len(aq.listInFlightPods()) != 0 {
+		t.Fatalf("in-flight pods should be cleaned up, but %v pod(s) is remaining", len(aq.listInFlightPods()))
+	}
+}