diff --git a/adapter/adapter.go b/adapter/adapter.go
index 6cc79c3a..c7351061 100644
--- a/adapter/adapter.go
+++ b/adapter/adapter.go
@@ -10,6 +10,7 @@ import (
 	"net/netip"
 	"net/url"
 	"strconv"
+	"sync"
 	"time"
 
 	"github.com/Dreamacro/clash/common/atomic"
@@ -36,7 +37,7 @@ type Proxy struct {
 	history *queue.Queue[C.DelayHistory]
 	alive   *atomic.Bool
 	url     string
-	extra   map[string]*extraProxyState
+	extra   sync.Map
 }
 
 // Alive implements C.Proxy
@@ -46,10 +47,8 @@ func (p *Proxy) Alive() bool {
 
 // AliveForTestUrl implements C.Proxy
 func (p *Proxy) AliveForTestUrl(url string) bool {
-	if p.extra != nil {
-		if state, ok := p.extra[url]; ok {
-			return state.alive.Load()
-		}
+	if state, ok := p.extra.Load(url); ok {
+		return state.(*extraProxyState).alive.Load()
 	}
 
 	return p.alive.Load()
@@ -88,16 +87,16 @@ func (p *Proxy) DelayHistory() []C.DelayHistory {
 	for _, item := range queueM {
 		histories = append(histories, item)
 	}
+
 	return histories
 }
 
 // DelayHistoryForTestUrl implements C.Proxy
 func (p *Proxy) DelayHistoryForTestUrl(url string) []C.DelayHistory {
 	var queueM []C.DelayHistory
-	if p.extra != nil {
-		if state, ok := p.extra[url]; ok {
-			queueM = state.history.Copy()
-		}
+
+	if state, ok := p.extra.Load(url); ok {
+		queueM = state.(*extraProxyState).history.Copy()
 	}
 
 	if queueM == nil {
@@ -112,19 +111,25 @@ func (p *Proxy) DelayHistoryForTestUrl(url string) []C.DelayHistory {
 }
 
 func (p *Proxy) ExtraDelayHistory() map[string][]C.DelayHistory {
-	extra := map[string][]C.DelayHistory{}
-	if p.extra != nil && len(p.extra) != 0 {
-		for testUrl, option := range p.extra {
-			histories := []C.DelayHistory{}
-			queueM := option.history.Copy()
-			for _, item := range queueM {
-				histories = append(histories, item)
-			}
+	extraHistory := map[string][]C.DelayHistory{}
 
-			extra[testUrl] = histories
+	p.extra.Range(func(k, v interface{}) bool {
+
+		testUrl := k.(string)
+		state := v.(*extraProxyState)
+
+		histories := []C.DelayHistory{}
+		queueM := state.history.Copy()
+
+		for _, item := range queueM {
+			histories = append(histories, item)
 		}
-	}
-	return extra
+
+		extraHistory[testUrl] = histories
+
+		return true
+	})
+	return extraHistory
 }
 
 // LastDelay return last history record. if proxy is not alive, return the max value of uint16.
@@ -149,11 +154,9 @@ func (p *Proxy) LastDelayForTestUrl(url string) (delay uint16) {
 	alive := p.alive.Load()
 	history := p.history.Last()
 
-	if p.extra != nil {
-		if state, ok := p.extra[url]; ok {
-			alive = state.alive.Load()
-			history = state.history.Last()
-		}
+	if state, ok := p.extra.Load(url); ok {
+		alive = state.(*extraProxyState).alive.Load()
+		history = state.(*extraProxyState).history.Last()
 	}
 
 	if !alive {
@@ -214,23 +217,19 @@ func (p *Proxy) URLTest(ctx context.Context, url string, expectedStatus utils.In
 				record.Delay = t
 			}
 
-			if p.extra == nil {
-				p.extra = map[string]*extraProxyState{}
-			}
-
-			state, ok := p.extra[url]
+			state, ok := p.extra.Load(url)
 			if !ok {
 				state = &extraProxyState{
 					history: queue.New[C.DelayHistory](defaultHistoriesNum),
 					alive:   atomic.NewBool(true),
 				}
-				p.extra[url] = state
+				p.extra.Store(url, state)
 			}
 
-			state.alive.Store(alive)
-			state.history.Put(record)
-			if state.history.Len() > defaultHistoriesNum {
-				state.history.Pop()
+			state.(*extraProxyState).alive.Store(alive)
+			state.(*extraProxyState).history.Put(record)
+			if state.(*extraProxyState).history.Len() > defaultHistoriesNum {
+				state.(*extraProxyState).history.Pop()
 			}
 		default:
 			log.Debugln("health check result will be discarded, url: %s alive: %t, delay: %d", url, alive, t)
@@ -307,7 +306,12 @@ func (p *Proxy) URLTest(ctx context.Context, url string, expectedStatus utils.In
 }
 
 func NewProxy(adapter C.ProxyAdapter) *Proxy {
-	return &Proxy{adapter, queue.New[C.DelayHistory](defaultHistoriesNum), atomic.NewBool(true), "", map[string]*extraProxyState{}}
+	return &Proxy{
+		ProxyAdapter: adapter,
+		history:      queue.New[C.DelayHistory](defaultHistoriesNum),
+		alive:        atomic.NewBool(true),
+		url:          "",
+		extra:        sync.Map{}}
 }
 
 func urlToMetadata(rawURL string) (addr C.Metadata, err error) {
@@ -350,14 +354,24 @@ func (p *Proxy) determineFinalStoreType(store C.DelayHistoryStoreType, url strin
 		return C.OriginalHistory
 	}
 
-	if p.extra == nil {
-		store = C.ExtraHistory
-	} else {
-		if _, ok := p.extra[url]; ok {
-			store = C.ExtraHistory
-		} else if len(p.extra) < 2*C.DefaultMaxHealthCheckUrlNum {
-			store = C.ExtraHistory
-		}
+	length := 0
+	p.extra.Range(func(_, _ interface{}) bool {
+		length++
+		return length < 2*C.DefaultMaxHealthCheckUrlNum
+	})
+
+	if length == 0 {
+		return C.ExtraHistory
 	}
+
+	_, ok := p.extra.Load(url)
+	if ok {
+		return C.ExtraHistory
+	}
+
+	if length < 2*C.DefaultMaxHealthCheckUrlNum {
+		return C.ExtraHistory
+	}
+
 	return store
 }