[PATCH] Fix equiv. cache invalidation of Node condition.

Equivalence cache for CheckNodeConditionPred becomes invalid when
Node.Spec.Unschedulable changes. This can happen even if
Node.Status.Conditions does not change, so move the logic around.

This logic is covered by integration test
"test/integration/scheduler".TestUnschedulableNodes but equivalence
cache is currently skipped when test pods have no OwnerReference.

Add benchmark for equivalence hashing.

Change equivalence hash function.

This changes the equivalence class hashing function to use as inputs all
the Pod fields which are read by FitPredicates. Before we used a
combination of OwnerReference and PersistentVolumeClaim info, which was
a close approximation. The new method ensures that hashing remains
correct regardless of controller behavior.

The PVCSet field can be removed from equivalencePod because it is
implicitly included in the Volume list.

Tests are now broken.

Move equivalence class hash code.

This moves the equivalence hashing code from
algorithm/predicates/utils.go to core/equivalence_cache.go.

In the process, making the hashing function and hashing function factory
both injectable dependencies is removed.

Fix equivalence cache hash tests.

Co-authored-by: Jonathan Basseri <misterikkit@google.com>
Co-authored-by: Harry Zhang <resouer@gmail.com>

pkg/scheduler/algorithm/predicates/utils.go

@@ -17,12 +17,8 @@ limitations under the License.
 package predicates
 
 import (
-	"github.com/golang/glog"
 	"k8s.io/api/core/v1"
-	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/labels"
-	"k8s.io/apimachinery/pkg/util/sets"
-	"k8s.io/kubernetes/pkg/scheduler/algorithm"
 	schedutil "k8s.io/kubernetes/pkg/scheduler/util"
 )
 
@@ -70,69 +66,6 @@ func CreateSelectorFromLabels(aL map[string]string) labels.Selector {
 	return labels.Set(aL).AsSelector()
 }
 
-// EquivalencePodGenerator is a generator of equivalence class for pod with consideration of PVC info.
-type EquivalencePodGenerator struct {
-	pvcInfo PersistentVolumeClaimInfo
-}
-
-// NewEquivalencePodGenerator returns a getEquivalencePod method with consideration of PVC info.
-func NewEquivalencePodGenerator(pvcInfo PersistentVolumeClaimInfo) algorithm.GetEquivalencePodFunc {
-	g := &EquivalencePodGenerator{
-		pvcInfo: pvcInfo,
-	}
-	return g.getEquivalencePod
-}
-
-// GetEquivalencePod returns a EquivalencePod which contains a group of pod attributes which can be reused.
-func (e *EquivalencePodGenerator) getEquivalencePod(pod *v1.Pod) interface{} {
-	// For now we only consider pods:
-	// 1. OwnerReferences is Controller
-	// 2. with same OwnerReferences
-	// 3. with same PVC claim
-	// to be equivalent
-	for _, ref := range pod.OwnerReferences {
-		if ref.Controller != nil && *ref.Controller {
-			pvcSet, err := e.getPVCSet(pod)
-			if err == nil {
-				// A pod can only belongs to one controller, so let's return.
-				return &EquivalencePod{
-					ControllerRef: ref,
-					PVCSet:        pvcSet,
-				}
-			}
-
-			// If error encountered, log warning and return nil (i.e. no equivalent pod found)
-			glog.Warningf("[EquivalencePodGenerator] for pod: %v failed due to: %v", pod.GetName(), err)
-			return nil
-		}
-	}
-	return nil
-}
-
-// getPVCSet returns a set of PVC UIDs of given pod.
-func (e *EquivalencePodGenerator) getPVCSet(pod *v1.Pod) (sets.String, error) {
-	result := sets.NewString()
-	for _, volume := range pod.Spec.Volumes {
-		if volume.PersistentVolumeClaim == nil {
-			continue
-		}
-		pvcName := volume.PersistentVolumeClaim.ClaimName
-		pvc, err := e.pvcInfo.GetPersistentVolumeClaimInfo(pod.GetNamespace(), pvcName)
-		if err != nil {
-			return nil, err
-		}
-		result.Insert(string(pvc.UID))
-	}
-
-	return result, nil
-}
-
-// EquivalencePod is a group of pod attributes which can be reused as equivalence to schedule other pods.
-type EquivalencePod struct {
-	ControllerRef metav1.OwnerReference
-	PVCSet        sets.String
-}
-
 // portsConflict check whether existingPorts and wantPorts conflict with each other
 // return true if we have a conflict
 func portsConflict(existingPorts schedutil.HostPortInfo, wantPorts []*v1.ContainerPort) bool {