Refactor Priority Reduce functions

- Reducing the duplicated reduce function by introducing a reduce
  function generator that generates common reduce functions.
- Remove logs from reduce function, so it's purely calculating scores.
- Optimize the reduce functions by removing unnecessary conversion to
  float64.

plugin/pkg/scheduler/algorithm/priorities/BUILD

@@ -18,6 +18,7 @@ go_library(
         "node_affinity.go",
         "node_label.go",
         "node_prefer_avoid_pods.go",
+        "reduce.go",
         "selector_spreading.go",
         "taint_toleration.go",
         "test_util.go",

plugin/pkg/scheduler/algorithm/priorities/node_affinity.go

@@ -24,8 +24,6 @@ import (
 	v1helper "k8s.io/kubernetes/pkg/api/v1/helper"
 	schedulerapi "k8s.io/kubernetes/plugin/pkg/scheduler/api"
 	"k8s.io/kubernetes/plugin/pkg/scheduler/schedulercache"
-
-	"github.com/golang/glog"
 )
 
 // CalculateNodeAffinityPriority prioritizes nodes according to node affinity scheduling preferences
@@ -76,28 +74,4 @@ func CalculateNodeAffinityPriorityMap(pod *v1.Pod, meta interface{}, nodeInfo *s
 	}, nil
 }
 
-func CalculateNodeAffinityPriorityReduce(pod *v1.Pod, meta interface{}, nodeNameToInfo map[string]*schedulercache.NodeInfo, result schedulerapi.HostPriorityList) error {
-	var maxCount int
-	for i := range result {
-		if result[i].Score > maxCount {
-			maxCount = result[i].Score
-		}
-	}
-	maxCountFloat := float64(maxCount)
-
-	var fScore float64
-	for i := range result {
-		if maxCount > 0 {
-			fScore = float64(schedulerapi.MaxPriority) * (float64(result[i].Score) / maxCountFloat)
-		} else {
-			fScore = 0
-		}
-		if glog.V(10) {
-			// We explicitly don't do glog.V(10).Infof() to avoid computing all the parameters if this is
-			// not logged. There is visible performance gain from it.
-			glog.Infof("%v -> %v: NodeAffinityPriority, Score: (%d)", pod.Name, result[i].Host, int(fScore))
-		}
-		result[i].Score = int(fScore)
-	}
-	return nil
-}
+var CalculateNodeAffinityPriorityReduce = NormalizeReduce(schedulerapi.MaxPriority, false)

plugin/pkg/scheduler/algorithm/priorities/reduce.go

@@ -0,0 +1,64 @@
+/*
+Copyright 2017 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 priorities
+
+import (
+	"k8s.io/api/core/v1"
+	"k8s.io/kubernetes/plugin/pkg/scheduler/algorithm"
+	schedulerapi "k8s.io/kubernetes/plugin/pkg/scheduler/api"
+	"k8s.io/kubernetes/plugin/pkg/scheduler/schedulercache"
+)
+
+// NormalizeReduce generates a PriorityReduceFunction that can normalize the result
+// scores to [0, maxPriority]. If reverse is set to true, it reverses the scores by
+// subtracting it from maxPriority.
+func NormalizeReduce(maxPriority int, reverse bool) algorithm.PriorityReduceFunction {
+	return func(
+		_ *v1.Pod,
+		_ interface{},
+		_ map[string]*schedulercache.NodeInfo,
+		result schedulerapi.HostPriorityList) error {
+
+		var maxCount int
+		for i := range result {
+			if result[i].Score > maxCount {
+				maxCount = result[i].Score
+			}
+		}
+
+		if maxCount == 0 {
+			if reverse {
+				for i := range result {
+					result[i].Score = maxPriority
+				}
+			}
+			return nil
+		}
+
+		for i := range result {
+			score := result[i].Score
+
+			score = maxPriority * score / maxCount
+			if reverse {
+				score = maxPriority - score
+			}
+
+			result[i].Score = score
+		}
+		return nil
+	}
+}

plugin/pkg/scheduler/algorithm/priorities/taint_toleration.go

@@ -23,8 +23,6 @@ import (
 	v1helper "k8s.io/kubernetes/pkg/api/v1/helper"
 	schedulerapi "k8s.io/kubernetes/plugin/pkg/scheduler/api"
 	"k8s.io/kubernetes/plugin/pkg/scheduler/schedulercache"
-
-	"github.com/golang/glog"
 )
 
 // CountIntolerableTaintsPreferNoSchedule gives the count of intolerable taints of a pod with effect PreferNoSchedule
@@ -75,26 +73,4 @@ func ComputeTaintTolerationPriorityMap(pod *v1.Pod, meta interface{}, nodeInfo *
 }
 
 // ComputeTaintTolerationPriorityReduce calculates the source of each node based on the number of intolerable taints on the node
-func ComputeTaintTolerationPriorityReduce(pod *v1.Pod, meta interface{}, nodeNameToInfo map[string]*schedulercache.NodeInfo, result schedulerapi.HostPriorityList) error {
-	var maxCount int
-	for i := range result {
-		if result[i].Score > maxCount {
-			maxCount = result[i].Score
-		}
-	}
-	maxCountFloat := float64(maxCount)
-
-	for i := range result {
-		fScore := float64(schedulerapi.MaxPriority)
-		if maxCountFloat > 0 {
-			fScore = (1.0 - float64(result[i].Score)/maxCountFloat) * float64(schedulerapi.MaxPriority)
-		}
-		if glog.V(10) {
-			// We explicitly don't do glog.V(10).Infof() to avoid computing all the parameters if this is
-			// not logged. There is visible performance gain from it.
-			glog.Infof("%v -> %v: Taint Toleration Priority, Score: (%d)", pod.Name, result[i].Host, int(fScore))
-		}
-		result[i].Score = int(fScore)
-	}
-	return nil
-}
+var ComputeTaintTolerationPriorityReduce = NormalizeReduce(schedulerapi.MaxPriority, true)

plugin/pkg/scheduler/algorithm/types.go

@@ -53,6 +53,7 @@ type MetadataProducer func(pod *v1.Pod, nodeNameToInfo map[string]*schedulercach
 type PriorityFunction func(pod *v1.Pod, nodeNameToInfo map[string]*schedulercache.NodeInfo, nodes []*v1.Node) (schedulerapi.HostPriorityList, error)
 
 type PriorityConfig struct {
+	Name   string
 	Map    PriorityMapFunction
 	Reduce PriorityReduceFunction
 	// TODO: Remove it after migrating all functions to