fix review comment

cluster/router/chain/chain.go

@@ -18,6 +18,7 @@
 package chain
 
 import (
+	"math"
 	"sort"
 	"sync"
 )
@@ -51,7 +52,7 @@ type RouterChain struct {
 func (c RouterChain) Route(invoker []protocol.Invoker, url *common.URL, invocation protocol.Invocation) []protocol.Invoker {
 	finalInvokers := invoker
 	l := len(c.routers)
-	rs := make([]router.Router, l, l)
+	rs := make([]router.Router, l, math.Ceil(float64(l)*1.2))
 	c.mutex.RLock()
 	copy(rs, c.routers)
 	c.mutex.RUnlock()

cluster/router/condition/listenable_router.go

@@ -90,7 +90,9 @@ func (l *listenableRouter) Process(event *config_center.ConfigChangeEvent) {
 	logger.Infof("Notification of condition rule, change type is:[%s] , raw rule is:[%v]", event.ConfigType, event.Value)
 	if remoting.EventTypeDel == event.ConfigType {
 		l.routerRule = nil
-		l.conditionRouters = make([]*ConditionRouter, 0)
+		if l.conditionRouters != nil {
+			l.conditionRouters = l.conditionRouters[:0]
+		}
 		return
 	}
 	content, ok := event.Value.(string)
@@ -112,7 +114,7 @@ func (l *listenableRouter) generateConditions(rule *RouterRule) {
 	if rule == nil || !rule.Valid {
 		return
 	}
-	l.conditionRouters = make([]*ConditionRouter, 0)
+	l.conditionRouters = make([]*ConditionRouter, 0, len(rule.Conditions))
 	l.routerRule = rule
 	for _, c := range rule.Conditions {
 		router, e := NewConditionRouterWithRule(c)