Parallelize taint manager

pkg/controller/nodelifecycle/scheduler/taint_manager.go

@@ -18,6 +18,8 @@ package scheduler
 
 import (
 	"fmt"
+	"hash/fnv"
+	"io"
 	"sync"
 	"time"
 
@@ -58,6 +60,32 @@ type podUpdateItem struct {
 	newTolerations []v1.Toleration
 }
 
+func (n *nodeUpdateItem) name() string {
+	if n.newNode != nil {
+		return n.newNode.ObjectMeta.Name
+	}
+	if n.oldNode != nil {
+		return n.oldNode.ObjectMeta.Name
+	}
+	return ""
+}
+
+func (p *podUpdateItem) nodeName() string {
+	if p.newPod != nil {
+		return p.newPod.Spec.NodeName
+	}
+	if p.oldPod != nil {
+		return p.oldPod.Spec.NodeName
+	}
+	return ""
+}
+
+func hash(val string) int {
+	hasher := fnv.New32a()
+	io.WriteString(hasher, val)
+	return int(hasher.Sum32())
+}
+
 // NoExecuteTaintManager listens to Taint/Toleration changes and is responsible for removing Pods
 // from Nodes tainted with NoExecute Taints.
 type NoExecuteTaintManager struct {
@@ -69,8 +97,8 @@ type NoExecuteTaintManager struct {
 	taintedNodesLock sync.Mutex
 	taintedNodes     map[string][]v1.Taint
 
-	nodeUpdateChannel chan *nodeUpdateItem
+	nodeUpdateChannels []chan *nodeUpdateItem
-	podUpdateChannel  chan *podUpdateItem
+	podUpdateChannels  []chan *podUpdateItem
 
 	nodeUpdateQueue workqueue.Interface
 	podUpdateQueue  workqueue.Interface
@@ -163,8 +191,6 @@ func NewNoExecuteTaintManager(c clientset.Interface) *NoExecuteTaintManager {
 		client:       c,
 		recorder:     recorder,
 		taintedNodes: make(map[string][]v1.Taint),
-		nodeUpdateChannel: make(chan *nodeUpdateItem, nodeUpdateChannelSize),
-		podUpdateChannel:  make(chan *podUpdateItem, podUpdateChannelSize),
 
 		nodeUpdateQueue: workqueue.New(),
 		podUpdateQueue:  workqueue.New(),
@@ -177,6 +203,15 @@ func NewNoExecuteTaintManager(c clientset.Interface) *NoExecuteTaintManager {
 // Run starts NoExecuteTaintManager which will run in loop until `stopCh` is closed.
 func (tc *NoExecuteTaintManager) Run(stopCh <-chan struct{}) {
 	glog.V(0).Infof("Starting NoExecuteTaintManager")
+
+	// TODO: Figure out a reasonable number of workers and propagate the
+	// number of workers up making it a paramater of Run() function.
+	workers := 8
+	for i := 0; i < workers; i++ {
+		tc.nodeUpdateChannels = append(tc.nodeUpdateChannels, make(chan *nodeUpdateItem, nodeUpdateChannelSize))
+		tc.podUpdateChannels = append(tc.podUpdateChannels, make(chan *podUpdateItem, podUpdateChannelSize))
+	}
+
 	// Functions that are responsible for taking work items out of the workqueues and putting them
 	// into channels.
 	go func(stopCh <-chan struct{}) {
@@ -186,10 +221,11 @@ func (tc *NoExecuteTaintManager) Run(stopCh <-chan struct{}) {
 				break
 			}
 			nodeUpdate := item.(*nodeUpdateItem)
+			hash := hash(nodeUpdate.name())
 			select {
 			case <-stopCh:
 				break
-			case tc.nodeUpdateChannel <- nodeUpdate:
+			case tc.nodeUpdateChannels[hash%workers] <- nodeUpdate:
 			}
 		}
 	}(stopCh)
@@ -201,14 +237,26 @@ func (tc *NoExecuteTaintManager) Run(stopCh <-chan struct{}) {
 				break
 			}
 			podUpdate := item.(*podUpdateItem)
+			hash := hash(podUpdate.nodeName())
 			select {
 			case <-stopCh:
 				break
-			case tc.podUpdateChannel <- podUpdate:
+			case tc.podUpdateChannels[hash%workers] <- podUpdate:
 			}
 		}
 	}(stopCh)
 
+	wg := sync.WaitGroup{}
+	wg.Add(workers)
+	for i := 0; i < workers; i++ {
+		go tc.worker(i, wg.Done, stopCh)
+	}
+	wg.Wait()
+}
+
+func (tc *NoExecuteTaintManager) worker(worker int, done func(), stopCh <-chan struct{}) {
+	defer done()
+
 	// When processing events we want to prioritize Node updates over Pod updates,
 	// as NodeUpdates that interest NoExecuteTaintManager should be handled as soon as possible -
 	// we don't want user (or system) to wait until PodUpdate queue is drained before it can
@@ -216,15 +264,15 @@ func (tc *NoExecuteTaintManager) Run(stopCh <-chan struct{}) {
 	for {
 		select {
 		case <-stopCh:
-			break
+			return
-		case nodeUpdate := <-tc.nodeUpdateChannel:
+		case nodeUpdate := <-tc.nodeUpdateChannels[worker]:
 			tc.handleNodeUpdate(nodeUpdate)
-		case podUpdate := <-tc.podUpdateChannel:
+		case podUpdate := <-tc.podUpdateChannels[worker]:
 			// If we found a Pod update we need to empty Node queue first.
 		priority:
 			for {
 				select {
-				case nodeUpdate := <-tc.nodeUpdateChannel:
+				case nodeUpdate := <-tc.nodeUpdateChannels[worker]:
 					tc.handleNodeUpdate(nodeUpdate)
 				default:
 					break priority