scheduling/config: watch StoreConfig in scheduling config watcher

pkg/mcs/scheduling/server/config/config.go

@@ -36,6 +36,7 @@ import (
 	"github.com/tikv/pd/pkg/utils/configutil"
 	"github.com/tikv/pd/pkg/utils/grpcutil"
 	"github.com/tikv/pd/pkg/utils/metricutil"
+	"github.com/tikv/pd/server/config"
 	"go.uber.org/zap"
 )
 
@@ -193,6 +194,7 @@ type PersistConfig struct {
 	clusterVersion unsafe.Pointer
 	schedule       atomic.Value
 	replication    atomic.Value
+	storeConfig    atomic.Value
 }
 
 // NewPersistConfig creates a new PersistConfig instance.
@@ -201,6 +203,9 @@ func NewPersistConfig(cfg *Config) *PersistConfig {
 	o.SetClusterVersion(&cfg.ClusterVersion)
 	o.schedule.Store(&cfg.Schedule)
 	o.replication.Store(&cfg.Replication)
+	// storeConfig will be fetched from TiKV by PD API server,
+	// so we just set an empty value here first.
+	o.storeConfig.Store(&config.StoreConfig{})
 	return o
 }
 
@@ -234,6 +239,19 @@ func (o *PersistConfig) SetReplicationConfig(cfg *sc.ReplicationConfig) {
 	o.replication.Store(cfg)
 }
 
+// SetStoreConfig sets the TiKV store configuration.
+func (o *PersistConfig) SetStoreConfig(cfg *config.StoreConfig) {
+	// Some of the fields won't be persisted and watched,
+	// so we need to adjust it here before storing it.
+	cfg.Adjust()
+	o.storeConfig.Store(cfg)
+}
+
+// GetStoreConfig returns the TiKV store configuration.
+func (o *PersistConfig) GetStoreConfig() *config.StoreConfig {
+	return o.storeConfig.Load().(*config.StoreConfig)
+}
+
 // GetMaxReplicas returns the max replicas.
 func (o *PersistConfig) GetMaxReplicas() int {
 	return int(o.GetReplicationConfig().MaxReplicas)

pkg/mcs/scheduling/server/config/watcher.go

@@ -23,6 +23,7 @@ import (
 	"github.com/pingcap/log"
 	sc "github.com/tikv/pd/pkg/schedule/config"
 	"github.com/tikv/pd/pkg/utils/etcdutil"
+	"github.com/tikv/pd/server/config"
 	"go.etcd.io/etcd/clientv3"
 	"go.etcd.io/etcd/mvcc/mvccpb"
 	"go.uber.org/zap"
@@ -42,9 +43,10 @@ type Watcher struct {
 }
 
 type persistedConfig struct {
+	ClusterVersion semver.Version       `json:"cluster-version"`
 	Schedule       sc.ScheduleConfig    `json:"schedule"`
 	Replication    sc.ReplicationConfig `json:"replication"`
-	ClusterVersion semver.Version       `json:"cluster-version"`
+	Store          config.StoreConfig   `json:"store"`
 }
 
 // NewWatcher creates a new watcher to watch the config meta change from PD API server.
@@ -71,9 +73,10 @@ func NewWatcher(
 				zap.String("event-kv-key", string(kv.Key)), zap.Error(err))
 			return err
 		}
+		cw.SetClusterVersion(&cfg.ClusterVersion)
 		cw.SetScheduleConfig(&cfg.Schedule)
 		cw.SetReplicationConfig(&cfg.Replication)
-		cw.SetClusterVersion(&cfg.ClusterVersion)
+		cw.SetStoreConfig(&cfg.Store)
 		return nil
 	}
 	deleteFn := func(kv *mvccpb.KeyValue) error {

tests/integrations/mcs/scheduling/config_test.go

@@ -25,6 +25,7 @@ import (
 	"github.com/tikv/pd/pkg/storage/endpoint"
 	"github.com/tikv/pd/pkg/utils/testutil"
 	"github.com/tikv/pd/pkg/versioninfo"
+	severcfg "github.com/tikv/pd/server/config"
 	"github.com/tikv/pd/tests"
 )
 
@@ -81,17 +82,31 @@ func (suite *configTestSuite) TestConfigWatch() {
 	re.Equal(sc.DefaultSplitMergeInterval, watcher.GetScheduleConfig().SplitMergeInterval.Duration)
 	re.Equal("0.0.0", watcher.GetClusterVersion().String())
 	// Update the config and check if the scheduling config watcher can get the latest value.
-	suite.pdLeaderServer.GetPersistOptions().SetMaxReplicas(5)
+	persistOpts := suite.pdLeaderServer.GetPersistOptions()
+	persistOpts.SetMaxReplicas(5)
 	persistConfig(re, suite.pdLeaderServer)
 	testutil.Eventually(re, func() bool {
 		return watcher.GetReplicationConfig().MaxReplicas == 5
 	})
-	suite.pdLeaderServer.GetPersistOptions().SetSplitMergeInterval(2 * sc.DefaultSplitMergeInterval)
+	persistOpts.SetSplitMergeInterval(2 * sc.DefaultSplitMergeInterval)
 	persistConfig(re, suite.pdLeaderServer)
 	testutil.Eventually(re, func() bool {
 		return watcher.GetScheduleConfig().SplitMergeInterval.Duration == 2*sc.DefaultSplitMergeInterval
 	})
-	suite.pdLeaderServer.GetPersistOptions().SetClusterVersion(versioninfo.MinSupportedVersion(versioninfo.Version4_0))
+	persistOpts.SetStoreConfig(&severcfg.StoreConfig{
+		Coprocessor: severcfg.Coprocessor{
+			RegionMaxSize: "144MiB",
+		},
+		Storage: severcfg.Storage{
+			Engine: severcfg.RaftstoreV2,
+		},
+	})
+	persistConfig(re, suite.pdLeaderServer)
+	testutil.Eventually(re, func() bool {
+		return watcher.GetStoreConfig().GetRegionMaxSize() == 144 &&
+			watcher.GetStoreConfig().IsRaftKV2()
+	})
+	persistOpts.SetClusterVersion(versioninfo.MinSupportedVersion(versioninfo.Version4_0))
 	persistConfig(re, suite.pdLeaderServer)
 	testutil.Eventually(re, func() bool {
 		return watcher.GetClusterVersion().String() == "4.0.0"