add service selector cache in endpoint controller and endpointSlice controller

pkg/controller/util/endpoint/controller_utils.go

@@ -22,9 +22,11 @@ import (
 	"fmt"
 	"reflect"
 	"sort"
+	"sync"
 
 	v1 "k8s.io/api/core/v1"
 	discovery "k8s.io/api/discovery/v1alpha1"
+	"k8s.io/apimachinery/pkg/labels"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/apimachinery/pkg/util/sets"
 	v1listers "k8s.io/client-go/listers/core/v1"
@@ -34,6 +36,76 @@ import (
 	"k8s.io/kubernetes/pkg/util/hash"
 )
 
+// ServiceSelectorCache is a cache of service selectors to avoid high CPU consumption caused by frequent calls to AsSelectorPreValidated (see #73527)
+type ServiceSelectorCache struct {
+	lock  sync.RWMutex
+	cache map[string]labels.Selector
+}
+
+// NewServiceSelectorCache init ServiceSelectorCache for both endpoint controller and endpointSlice controller.
+func NewServiceSelectorCache() *ServiceSelectorCache {
+	return &ServiceSelectorCache{
+		cache: map[string]labels.Selector{},
+	}
+}
+
+// Get return selector and existence in ServiceSelectorCache by key.
+func (sc *ServiceSelectorCache) Get(key string) (labels.Selector, bool) {
+	sc.lock.RLock()
+	selector, ok := sc.cache[key]
+	// fine-grained lock improves GetPodServiceMemberships performance(16.5%) than defer measured by BenchmarkGetPodServiceMemberships
+	sc.lock.RUnlock()
+	return selector, ok
+}
+
+// Update can update or add a selector in ServiceSelectorCache while service's selector changed.
+func (sc *ServiceSelectorCache) Update(key string, rawSelector map[string]string) labels.Selector {
+	sc.lock.Lock()
+	defer sc.lock.Unlock()
+	selector := labels.Set(rawSelector).AsSelectorPreValidated()
+	sc.cache[key] = selector
+	return selector
+}
+
+// Delete can delete selector which exist in ServiceSelectorCache.
+func (sc *ServiceSelectorCache) Delete(key string) {
+	sc.lock.Lock()
+	defer sc.lock.Unlock()
+	delete(sc.cache, key)
+}
+
+// GetPodServiceMemberships returns a set of Service keys for Services that have
+// a selector matching the given pod.
+func (sc *ServiceSelectorCache) GetPodServiceMemberships(serviceLister v1listers.ServiceLister, pod *v1.Pod) (sets.String, error) {
+	set := sets.String{}
+	services, err := serviceLister.Services(pod.Namespace).List(labels.Everything())
+	if err != nil {
+		return set, err
+	}
+
+	var selector labels.Selector
+	for _, service := range services {
+		if service.Spec.Selector == nil {
+			// if the service has a nil selector this means selectors match nothing, not everything.
+			continue
+		}
+		key, err := controller.KeyFunc(service)
+		if err != nil {
+			return nil, err
+		}
+		if v, ok := sc.Get(key); ok {
+			selector = v
+		} else {
+			selector = sc.Update(key, service.Spec.Selector)
+		}
+
+		if selector.Matches(labels.Set(pod.Labels)) {
+			set.Insert(key)
+		}
+	}
+	return set, nil
+}
+
 // EndpointsMatch is a type of function that returns true if pod endpoints match.
 type EndpointsMatch func(*v1.Pod, *v1.Pod) bool
 
@@ -100,29 +172,9 @@ func PodChanged(oldPod, newPod *v1.Pod, endpointChanged EndpointsMatch) (bool, b
 	return endpointChanged(newPod, oldPod), labelsChanged
 }
 
-// GetPodServiceMemberships returns a set of Service keys for Services that have
-// a selector matching the given pod.
-func GetPodServiceMemberships(serviceLister v1listers.ServiceLister, pod *v1.Pod) (sets.String, error) {
-	set := sets.String{}
-	services, err := serviceLister.GetPodServices(pod)
-	if err != nil {
-		// don't log this error because this function makes pointless
-		// errors when no services match
-		return set, nil
-	}
-	for i := range services {
-		key, err := controller.KeyFunc(services[i])
-		if err != nil {
-			return nil, err
-		}
-		set.Insert(key)
-	}
-	return set, nil
-}
-
 // GetServicesToUpdateOnPodChange returns a set of Service keys for Services
 // that have potentially been affected by a change to this pod.
-func GetServicesToUpdateOnPodChange(serviceLister v1listers.ServiceLister, old, cur interface{}, endpointChanged EndpointsMatch) sets.String {
+func GetServicesToUpdateOnPodChange(serviceLister v1listers.ServiceLister, selectorCache *ServiceSelectorCache, old, cur interface{}, endpointChanged EndpointsMatch) sets.String {
 	newPod := cur.(*v1.Pod)
 	oldPod := old.(*v1.Pod)
 	if newPod.ResourceVersion == oldPod.ResourceVersion {
@@ -138,14 +190,14 @@ func GetServicesToUpdateOnPodChange(serviceLister v1listers.ServiceLister, old,
 		return sets.String{}
 	}
 
-	services, err := GetPodServiceMemberships(serviceLister, newPod)
+	services, err := selectorCache.GetPodServiceMemberships(serviceLister, newPod)
 	if err != nil {
 		utilruntime.HandleError(fmt.Errorf("Unable to get pod %s/%s's service memberships: %v", newPod.Namespace, newPod.Name, err))
 		return sets.String{}
 	}
 
 	if labelsChanged {
-		oldServices, err := GetPodServiceMemberships(serviceLister, oldPod)
+		oldServices, err := selectorCache.GetPodServiceMemberships(serviceLister, oldPod)
 		if err != nil {
 			utilruntime.HandleError(fmt.Errorf("Unable to get pod %s/%s's service memberships: %v", newPod.Namespace, newPod.Name, err))
 		}