address the comment

Signed-off-by: Ryan Leung <rleungx@gmail.com>

pkg/keyspace/keyspace.go

@@ -26,8 +26,8 @@ import (
 	"github.com/pingcap/log"
 	"github.com/tikv/pd/pkg/id"
 	"github.com/tikv/pd/pkg/mcs/utils"
+	"github.com/tikv/pd/pkg/schedule/core"
 	"github.com/tikv/pd/pkg/schedule/labeler"
-	"github.com/tikv/pd/pkg/schedule/scheduling"
 	"github.com/tikv/pd/pkg/slice"
 	"github.com/tikv/pd/pkg/storage/endpoint"
 	"github.com/tikv/pd/pkg/storage/kv"
@@ -71,7 +71,7 @@ type Manager struct {
 	// store is the storage for keyspace related information.
 	store endpoint.KeyspaceStorage
 	// rc is the raft cluster of the server.
-	cluster scheduling.ClusterInformer
+	cluster core.ClusterInformer
 	// ctx is the context of the manager, to be used in transaction.
 	ctx context.Context
 	// config is the configurations of the manager.
@@ -98,7 +98,7 @@ type CreateKeyspaceRequest struct {
 func NewKeyspaceManager(
 	ctx context.Context,
 	store endpoint.KeyspaceStorage,
-	cluster scheduling.ClusterInformer,
+	cluster core.ClusterInformer,
 	idAllocator id.Allocator,
 	config Config,
 	kgm *GroupManager,

pkg/schedule/checker/checker_controller.go

@@ -24,10 +24,10 @@ import (
 	"github.com/tikv/pd/pkg/errs"
 	"github.com/tikv/pd/pkg/schedule"
 	"github.com/tikv/pd/pkg/schedule/config"
+	sche "github.com/tikv/pd/pkg/schedule/core"
 	"github.com/tikv/pd/pkg/schedule/labeler"
 	"github.com/tikv/pd/pkg/schedule/operator"
 	"github.com/tikv/pd/pkg/schedule/placement"
-	"github.com/tikv/pd/pkg/schedule/scheduling"
 	"github.com/tikv/pd/pkg/utils/keyutil"
 )
 
@@ -38,7 +38,7 @@ var denyCheckersByLabelerCounter = schedule.LabelerEventCounter.WithLabelValues(
 
 // Controller is used to manage all checkers.
 type Controller struct {
-	cluster           scheduling.ClusterInformer
+	cluster           sche.ClusterInformer
 	conf              config.Config
 	opController      *schedule.OperatorController
 	learnerChecker    *LearnerChecker
@@ -54,7 +54,7 @@ type Controller struct {
 }
 
 // NewController create a new Controller.
-func NewController(ctx context.Context, cluster scheduling.ClusterInformer, conf config.Config, ruleManager *placement.RuleManager, labeler *labeler.RegionLabeler, opController *schedule.OperatorController) *Controller {
+func NewController(ctx context.Context, cluster sche.ClusterInformer, conf config.Config, ruleManager *placement.RuleManager, labeler *labeler.RegionLabeler, opController *schedule.OperatorController) *Controller {
 	regionWaitingList := cache.NewDefaultCache(DefaultCacheSize)
 	return &Controller{
 		cluster:           cluster,

pkg/schedule/checker/joint_state_checker.go

@@ -19,14 +19,14 @@ import (
 	"github.com/tikv/pd/pkg/core"
 	"github.com/tikv/pd/pkg/core/constant"
 	"github.com/tikv/pd/pkg/errs"
+	sche "github.com/tikv/pd/pkg/schedule/core"
 	"github.com/tikv/pd/pkg/schedule/operator"
-	"github.com/tikv/pd/pkg/schedule/scheduling"
 )
 
 // JointStateChecker ensures region is in joint state will leave.
 type JointStateChecker struct {
 	PauseController
-	cluster scheduling.ClusterInformer
+	cluster sche.ClusterInformer
 }
 
 const jointStateCheckerName = "joint_state_checker"
@@ -41,7 +41,7 @@ var (
 )
 
 // NewJointStateChecker creates a joint state checker.
-func NewJointStateChecker(cluster scheduling.ClusterInformer) *JointStateChecker {
+func NewJointStateChecker(cluster sche.ClusterInformer) *JointStateChecker {
 	return &JointStateChecker{
 		cluster: cluster,
 	}

pkg/schedule/checker/learner_checker.go

@@ -18,14 +18,14 @@ import (
 	"github.com/pingcap/log"
 	"github.com/tikv/pd/pkg/core"
 	"github.com/tikv/pd/pkg/errs"
+	sche "github.com/tikv/pd/pkg/schedule/core"
 	"github.com/tikv/pd/pkg/schedule/operator"
-	"github.com/tikv/pd/pkg/schedule/scheduling"
 )
 
 // LearnerChecker ensures region has a learner will be promoted.
 type LearnerChecker struct {
 	PauseController
-	cluster scheduling.ClusterInformer
+	cluster sche.ClusterInformer
 }
 
 var (
@@ -34,7 +34,7 @@ var (
 )
 
 // NewLearnerChecker creates a learner checker.
-func NewLearnerChecker(cluster scheduling.ClusterInformer) *LearnerChecker {
+func NewLearnerChecker(cluster sche.ClusterInformer) *LearnerChecker {
 	return &LearnerChecker{
 		cluster: cluster,
 	}

pkg/schedule/checker/merge_checker.go

@@ -26,11 +26,11 @@ import (
 	"github.com/tikv/pd/pkg/core/constant"
 	"github.com/tikv/pd/pkg/errs"
 	"github.com/tikv/pd/pkg/schedule/config"
+	sche "github.com/tikv/pd/pkg/schedule/core"
 	"github.com/tikv/pd/pkg/schedule/filter"
 	"github.com/tikv/pd/pkg/schedule/labeler"
 	"github.com/tikv/pd/pkg/schedule/operator"
 	"github.com/tikv/pd/pkg/schedule/placement"
-	"github.com/tikv/pd/pkg/schedule/scheduling"
 	"github.com/tikv/pd/pkg/utils/logutil"
 )
 
@@ -76,14 +76,14 @@ var (
 // MergeChecker ensures region to merge with adjacent region when size is small
 type MergeChecker struct {
 	PauseController
-	cluster    scheduling.ClusterInformer
+	cluster    sche.ClusterInformer
 	conf       config.Config
 	splitCache *cache.TTLUint64
 	startTime  time.Time // it's used to judge whether server recently start.
 }
 
 // NewMergeChecker creates a merge checker.
-func NewMergeChecker(ctx context.Context, cluster scheduling.ClusterInformer, conf config.Config) *MergeChecker {
+func NewMergeChecker(ctx context.Context, cluster sche.ClusterInformer, conf config.Config) *MergeChecker {
 	splitCache := cache.NewIDTTL(ctx, time.Minute, conf.GetSplitMergeInterval())
 	return &MergeChecker{
 		cluster:    cluster,
@@ -250,7 +250,7 @@ func (m *MergeChecker) checkTarget(region, adjacent *core.RegionInfo) bool {
 }
 
 // AllowMerge returns true if two regions can be merged according to the key type.
-func AllowMerge(cluster scheduling.ClusterInformer, region, adjacent *core.RegionInfo) bool {
+func AllowMerge(cluster sche.ClusterInformer, region, adjacent *core.RegionInfo) bool {
 	var start, end []byte
 	if bytes.Equal(region.GetEndKey(), adjacent.GetStartKey()) && len(region.GetEndKey()) != 0 {
 		start, end = region.GetStartKey(), adjacent.GetEndKey()
@@ -306,7 +306,7 @@ func isTableIDSame(region, adjacent *core.RegionInfo) bool {
 // Check whether there is a peer of the adjacent region on an offline store,
 // while the source region has no peer on it. This is to prevent from bringing
 // any other peer into an offline store to slow down the offline process.
-func checkPeerStore(cluster scheduling.ClusterInformer, region, adjacent *core.RegionInfo) bool {
+func checkPeerStore(cluster sche.ClusterInformer, region, adjacent *core.RegionInfo) bool {
 	regionStoreIDs := region.GetStoreIDs()
 	for _, peer := range adjacent.GetPeers() {
 		storeID := peer.GetStoreId()

pkg/schedule/checker/priority_inspector.go

@@ -20,22 +20,22 @@ import (
 	"github.com/tikv/pd/pkg/cache"
 	"github.com/tikv/pd/pkg/core"
 	"github.com/tikv/pd/pkg/schedule/config"
+	sche "github.com/tikv/pd/pkg/schedule/core"
 	"github.com/tikv/pd/pkg/schedule/placement"
-	"github.com/tikv/pd/pkg/schedule/scheduling"
 )
 
 // the default value of priority queue size
 const defaultPriorityQueueSize = 1280
 
 // PriorityInspector ensures high priority region should run first
 type PriorityInspector struct {
-	cluster scheduling.ClusterInformer
+	cluster sche.ClusterInformer
 	conf    config.Config
 	queue   *cache.PriorityQueue
 }
 
 // NewPriorityInspector creates a priority inspector.
-func NewPriorityInspector(cluster scheduling.ClusterInformer, conf config.Config) *PriorityInspector {
+func NewPriorityInspector(cluster sche.ClusterInformer, conf config.Config) *PriorityInspector {
 	return &PriorityInspector{
 		cluster: cluster,
 		conf:    conf,

pkg/schedule/checker/replica_checker.go

@@ -24,8 +24,8 @@ import (
 	"github.com/tikv/pd/pkg/core/constant"
 	"github.com/tikv/pd/pkg/errs"
 	"github.com/tikv/pd/pkg/schedule/config"
+	sche "github.com/tikv/pd/pkg/schedule/core"
 	"github.com/tikv/pd/pkg/schedule/operator"
-	"github.com/tikv/pd/pkg/schedule/scheduling"
 	"go.uber.org/zap"
 )
 
@@ -61,13 +61,13 @@ var (
 // Location management, mainly used for cross data center deployment.
 type ReplicaChecker struct {
 	PauseController
-	cluster           scheduling.ClusterInformer
+	cluster           sche.ClusterInformer
 	conf              config.Config
 	regionWaitingList cache.Cache
 }
 
 // NewReplicaChecker creates a replica checker.
-func NewReplicaChecker(cluster scheduling.ClusterInformer, conf config.Config, regionWaitingList cache.Cache) *ReplicaChecker {
+func NewReplicaChecker(cluster sche.ClusterInformer, conf config.Config, regionWaitingList cache.Cache) *ReplicaChecker {
 	return &ReplicaChecker{
 		cluster:           cluster,
 		conf:              conf,

pkg/schedule/checker/replica_strategy.go

@@ -18,16 +18,16 @@ import (
 	"github.com/pingcap/log"
 	"github.com/tikv/pd/pkg/core"
 	"github.com/tikv/pd/pkg/core/constant"
+	sche "github.com/tikv/pd/pkg/schedule/core"
 	"github.com/tikv/pd/pkg/schedule/filter"
-	"github.com/tikv/pd/pkg/schedule/scheduling"
 	"go.uber.org/zap"
 )
 
 // ReplicaStrategy collects some utilities to manipulate region peers. It
 // exists to allow replica_checker and rule_checker to reuse common logics.
 type ReplicaStrategy struct {
 	checkerName    string // replica-checker / rule-checker
-	cluster        scheduling.ClusterInformer
+	cluster        sche.ClusterInformer
 	locationLabels []string
 	isolationLevel string
 	region         *core.RegionInfo

pkg/schedule/checker/rule_checker.go

@@ -27,10 +27,10 @@ import (
 	"github.com/tikv/pd/pkg/core"
 	"github.com/tikv/pd/pkg/core/constant"
 	"github.com/tikv/pd/pkg/errs"
+	sche "github.com/tikv/pd/pkg/schedule/core"
 	"github.com/tikv/pd/pkg/schedule/filter"
 	"github.com/tikv/pd/pkg/schedule/operator"
 	"github.com/tikv/pd/pkg/schedule/placement"
-	"github.com/tikv/pd/pkg/schedule/scheduling"
 	"github.com/tikv/pd/pkg/versioninfo"
 	"go.uber.org/zap"
 )
@@ -81,7 +81,7 @@ var (
 // RuleChecker fix/improve region by placement rules.
 type RuleChecker struct {
 	PauseController
-	cluster            scheduling.ClusterInformer
+	cluster            sche.ClusterInformer
 	ruleManager        *placement.RuleManager
 	name               string
 	regionWaitingList  cache.Cache
@@ -91,7 +91,7 @@ type RuleChecker struct {
 }
 
 // NewRuleChecker creates a checker instance.
-func NewRuleChecker(ctx context.Context, cluster scheduling.ClusterInformer, ruleManager *placement.RuleManager, regionWaitingList cache.Cache) *RuleChecker {
+func NewRuleChecker(ctx context.Context, cluster sche.ClusterInformer, ruleManager *placement.RuleManager, regionWaitingList cache.Cache) *RuleChecker {
 	return &RuleChecker{
 		cluster:            cluster,
 		ruleManager:        ruleManager,
@@ -572,7 +572,7 @@ func (o *recorder) incOfflineLeaderCount(storeID uint64) {
 // Offline is triggered manually and only appears when the node makes some adjustments. here is an operator timeout / 2.
 var offlineCounterTTL = 5 * time.Minute
 
-func (o *recorder) refresh(cluster scheduling.ClusterInformer) {
+func (o *recorder) refresh(cluster sche.ClusterInformer) {
 	// re-count the offlineLeaderCounter if the store is already tombstone or store is gone.
 	if len(o.offlineLeaderCounter) > 0 && time.Since(o.lastUpdateTime) > offlineCounterTTL {
 		needClean := false

pkg/schedule/checker/split_checker.go

@@ -19,16 +19,16 @@ import (
 	"github.com/pingcap/log"
 	"github.com/tikv/pd/pkg/core"
 	"github.com/tikv/pd/pkg/errs"
+	sche "github.com/tikv/pd/pkg/schedule/core"
 	"github.com/tikv/pd/pkg/schedule/labeler"
 	"github.com/tikv/pd/pkg/schedule/operator"
 	"github.com/tikv/pd/pkg/schedule/placement"
-	"github.com/tikv/pd/pkg/schedule/scheduling"
 )
 
 // SplitChecker splits regions when the key range spans across rule/label boundary.
 type SplitChecker struct {
 	PauseController
-	cluster     scheduling.ClusterInformer
+	cluster     sche.ClusterInformer
 	ruleManager *placement.RuleManager
 	labeler     *labeler.RegionLabeler
 }
@@ -42,7 +42,7 @@ var (
 )
 
 // NewSplitChecker creates a new SplitChecker.
-func NewSplitChecker(cluster scheduling.ClusterInformer, ruleManager *placement.RuleManager, labeler *labeler.RegionLabeler) *SplitChecker {
+func NewSplitChecker(cluster sche.ClusterInformer, ruleManager *placement.RuleManager, labeler *labeler.RegionLabeler) *SplitChecker {
 	return &SplitChecker{
 		cluster:     cluster,
 		ruleManager: ruleManager,

pkg/schedule/scheduling/cluster_informer.go → pkg/schedule/core/cluster_informer.go

@@ -1,4 +1,4 @@
-// Copyright 2020 TiKV Project Authors.
+// Copyright 2017 TiKV Project Authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package scheduling
+package core
 
 import (
 	"github.com/tikv/pd/pkg/core"

pkg/schedule/filter/healthy.go

@@ -16,7 +16,7 @@ package filter
 
 import (
 	"github.com/tikv/pd/pkg/core"
-	"github.com/tikv/pd/pkg/schedule/scheduling"
+	sche "github.com/tikv/pd/pkg/schedule/core"
 )
 
 // IsRegionHealthy checks if a region is healthy for scheduling. It requires the
@@ -42,17 +42,17 @@ func hasDownPeers(region *core.RegionInfo) bool {
 // IsRegionReplicated checks if a region is fully replicated. When placement
 // rules is enabled, its peers should fit corresponding rules. When placement
 // rules is disabled, it should have enough replicas and no any learner peer.
-func IsRegionReplicated(cluster scheduling.RegionHealthCluster, region *core.RegionInfo) bool {
+func IsRegionReplicated(cluster sche.RegionHealthCluster, region *core.RegionInfo) bool {
 	if cluster.GetOpts().IsPlacementRulesEnabled() {
 		return isRegionPlacementRuleSatisfied(cluster, region)
 	}
 	return isRegionReplicasSatisfied(cluster, region)
 }
 
-func isRegionPlacementRuleSatisfied(cluster scheduling.RegionHealthCluster, region *core.RegionInfo) bool {
+func isRegionPlacementRuleSatisfied(cluster sche.RegionHealthCluster, region *core.RegionInfo) bool {
 	return cluster.GetRuleManager().FitRegion(cluster, region).IsSatisfied()
 }
 
-func isRegionReplicasSatisfied(cluster scheduling.RegionHealthCluster, region *core.RegionInfo) bool {
+func isRegionReplicasSatisfied(cluster sche.RegionHealthCluster, region *core.RegionInfo) bool {
 	return len(region.GetLearners()) == 0 && len(region.GetPeers()) == cluster.GetOpts().GetMaxReplicas()
 }

pkg/schedule/filter/region_filters.go

@@ -18,9 +18,9 @@ import (
 	"github.com/tikv/pd/pkg/core"
 	"github.com/tikv/pd/pkg/core/constant"
 	"github.com/tikv/pd/pkg/core/storelimit"
+	sche "github.com/tikv/pd/pkg/schedule/core"
 	"github.com/tikv/pd/pkg/schedule/placement"
 	"github.com/tikv/pd/pkg/schedule/plan"
-	"github.com/tikv/pd/pkg/schedule/scheduling"
 	"github.com/tikv/pd/pkg/slice"
 )
 
@@ -100,12 +100,12 @@ func (f *regionDownFilter) Select(region *core.RegionInfo) *plan.Status {
 
 // RegionReplicatedFilter filters all unreplicated regions.
 type RegionReplicatedFilter struct {
-	cluster scheduling.RegionHealthCluster
+	cluster sche.RegionHealthCluster
 	fit     *placement.RegionFit
 }
 
 // NewRegionReplicatedFilter creates a RegionFilter that filters all unreplicated regions.
-func NewRegionReplicatedFilter(cluster scheduling.RegionHealthCluster) RegionFilter {
+func NewRegionReplicatedFilter(cluster sche.RegionHealthCluster) RegionFilter {
 	return &RegionReplicatedFilter{cluster: cluster}
 }
 
@@ -132,11 +132,11 @@ func (f *RegionReplicatedFilter) Select(region *core.RegionInfo) *plan.Status {
 }
 
 type regionEmptyFilter struct {
-	cluster scheduling.RegionHealthCluster
+	cluster sche.RegionHealthCluster
 }
 
 // NewRegionEmptyFilter returns creates a RegionFilter that filters all empty regions.
-func NewRegionEmptyFilter(cluster scheduling.RegionHealthCluster) RegionFilter {
+func NewRegionEmptyFilter(cluster sche.RegionHealthCluster) RegionFilter {
 	return &regionEmptyFilter{cluster: cluster}
 }
 
@@ -148,7 +148,7 @@ func (f *regionEmptyFilter) Select(region *core.RegionInfo) *plan.Status {
 }
 
 // isEmptyRegionAllowBalance returns true if the region is not empty or the number of regions is too small.
-func isEmptyRegionAllowBalance(cluster scheduling.RegionHealthCluster, region *core.RegionInfo) bool {
+func isEmptyRegionAllowBalance(cluster sche.RegionHealthCluster, region *core.RegionInfo) bool {
 	return region.GetApproximateSize() > core.EmptyRegionApproximateSize || cluster.GetRegionCount() < core.InitClusterRegionThreshold
 }