diff --git a/callbacks.go b/callbacks.go
index 4544730..e2402f7 100644
--- a/callbacks.go
+++ b/callbacks.go
@@ -11,6 +11,7 @@ import (
 	"io"
 	"net/http"
 	"net/url"
+	"runtime"
 	"strconv"
 	"strings"
 	"sync"
@@ -160,9 +161,11 @@ func onBeginHeaderCallback(ptr unsafe.Pointer, streamID C.int) C.int {
 		},
 	}
 	s.request.Body = s.bp
-
+	//log.Printf("new stream %d", int(streamID))
 	conn.streams[int(streamID)] = s
 
+	runtime.SetFinalizer(s, (*stream).free)
+
 	//log.Println("onBeginHeaderCallback end")
 	return NGHTTP2_NO_ERROR
 }
@@ -274,6 +277,7 @@ func onStreamClose(ptr unsafe.Pointer, streamID C.int) C.int {
 	stream, ok := conn.streams[int(streamID)]
 	if ok {
 		go stream.Close()
+		//log.Printf("remove stream %d", int(streamID))
 		//conn.lock.Lock()
 		delete(conn.streams, int(streamID))
 		//go stream.Close()
@@ -291,7 +295,7 @@ func onConnectionCloseCallback(ptr unsafe.Pointer) {
 	conn.err = io.EOF
 
 	// signal all goroutings exit
-	for i := 0; i < 4; i++ {
+	for i := 0; i < 6; i++ {
 		select {
 		case conn.exitch <- struct{}{}:
 		default:
diff --git a/conn.go b/conn.go
index 81385ad..5fc1622 100644
--- a/conn.go
+++ b/conn.go
@@ -14,6 +14,7 @@ import (
 	"net"
 	"net/http"
 	"net/url"
+	"runtime"
 	"strings"
 	"sync"
 	"time"
@@ -79,6 +80,8 @@ func Server(c net.Conn, handler http.Handler) (*Conn, error) {
 		isServer: true,
 		streams:  make(map[int]*stream),
 	}
+	//log.Printf("new conn %x", uintptr(unsafe.Pointer(conn)))
+	runtime.SetFinalizer(conn, (*Conn).free)
 	conn.session = C.init_nghttp2_server_session(C.size_t(uintptr(unsafe.Pointer(conn))))
 	if conn.session == nil {
 		return nil, errors.New("init server session failed")
@@ -104,6 +107,8 @@ func Client(c net.Conn) (*Conn, error) {
 		lock:    new(sync.Mutex),
 		streams: make(map[int]*stream),
 	}
+	//log.Printf("new conn %x", uintptr(unsafe.Pointer(conn)))
+	runtime.SetFinalizer(conn, (*Conn).free)
 	conn.session = C.init_nghttp2_client_session(C.size_t(uintptr(unsafe.Pointer(conn))))
 	if conn.session == nil {
 		return nil, errors.New("init server session failed")
@@ -138,6 +143,17 @@ func HTTP2Handler(srv *http.Server, conn *tls.Conn, handler http.Handler) {
 	h2conn.Run()
 }
 
+func (c *Conn) free() {
+	//log.Printf("free conn %x", uintptr(unsafe.Pointer(c)))
+	if !c.closed {
+		c.Close()
+	}
+	c.conn = nil
+	c.session = nil
+	c.streams = nil
+	c.lock = nil
+}
+
 // Error return conn error
 func (c *Conn) Error() error {
 	c.lock.Lock()
@@ -239,6 +255,7 @@ func (c *Conn) submitRequest(nv []C.nghttp2_nv, cdp *C.nghttp2_data_provider) (*
 	if cdp != nil {
 		s.cdp = *cdp
 	}
+	runtime.SetFinalizer(s, (*stream).free)
 	return s, nil
 }
 
@@ -335,6 +352,10 @@ func (c *Conn) Close() error {
 		s.Close()
 	}
 
+	for n := range c.streams {
+		delete(c.streams, n)
+	}
+
 	c.lock.Lock()
 	C.nghttp2_session_terminate_session(c.session, 0)
 	C.nghttp2_session_del(c.session)
@@ -353,27 +374,27 @@ func (c *Conn) errorNotify(err error) {
 }
 
 func (c *Conn) readloop() {
-	type data struct {
-		buf []byte
-		err error
-	}
 
 	var ret C.ssize_t
 	var err error
-	var d data
-
-	datach := make(chan data)
 
+	datach := make(chan []byte)
 	go func() {
-		d1 := data{}
 		var n int
 		var err1 error
 		for {
+			select {
+			case <-c.exitch:
+				return
+			default:
+			}
 			buf := make([]byte, 16*1024)
 			n, err1 = c.conn.Read(buf)
-			d1.buf = buf[:n]
-			d1.err = err1
-			datach <- d1
+			if err1 != nil {
+				c.errorNotify(err1)
+				break
+			}
+			datach <- buf[:n]
 		}
 	}()
 
@@ -381,14 +402,14 @@ func (c *Conn) readloop() {
 		select {
 		case <-c.exitch:
 			return
-		case d = <-datach:
-			if d.err != nil {
-				c.errorNotify(d.err)
+		case d := <-datach:
+			c.lock.Lock()
+			if c.closed {
+				c.lock.Unlock()
 				return
 			}
-			c.lock.Lock()
 			ret = C.nghttp2_session_mem_recv(c.session,
-				(*C.uchar)(unsafe.Pointer(&d.buf[0])), C.size_t(len(d.buf)))
+				(*C.uchar)(unsafe.Pointer(&d[0])), C.size_t(len(d)))
 			c.lock.Unlock()
 			if int(ret) < 0 {
 				err = fmt.Errorf("http2 recv error: %s", C.GoString(C.nghttp2_strerror(C.int(ret))))
@@ -403,6 +424,7 @@ func (c *Conn) writeloop() {
 	var ret C.int
 	var err error
 	var delay = 50 * time.Millisecond
+
 	for {
 		select {
 		case <-c.exitch:
diff --git a/data_provider.go b/data_provider.go
index 42b8c93..ca7a986 100644
--- a/data_provider.go
+++ b/data_provider.go
@@ -7,6 +7,7 @@ import "C"
 import (
 	"bytes"
 	"errors"
+	"io"
 	"log"
 	"sync"
 	"time"
@@ -51,6 +52,24 @@ func (dp *dataProvider) Write(buf []byte) (n int, err error) {
 		log.Println("dp write invalid state")
 		return 0, errors.New("invalid state")
 	}
+
+	// make sure the buffer not too large
+	delay := 10 * time.Millisecond
+	maxBufSize := 1 * 1024 * 1024
+	for {
+		dp.lock.Lock()
+		_len := dp.buf.Len()
+		closed := dp.closed
+		dp.lock.Unlock()
+		if closed {
+			return 0, io.EOF
+		}
+		if _len < maxBufSize {
+			break
+		}
+		time.Sleep(delay)
+	}
+
 	dp.lock.Lock()
 	defer dp.lock.Unlock()
 
diff --git a/stream.go b/stream.go
index 3d5cd70..0ccfd96 100644
--- a/stream.go
+++ b/stream.go
@@ -31,6 +31,29 @@ type stream struct {
 
 var _ net.Conn = &stream{}
 
+func (s *stream) free() {
+	//log.Printf("stream free %d", s.streamID)
+	if !s.closed {
+		s.Close()
+	}
+	s.conn = nil
+	if s.dp != nil {
+		s.dp.buf = nil
+		s.dp.lock = nil
+		s.dp.sessLock = nil
+		s.dp.session = nil
+		s.dp = nil
+	}
+	if s.bp != nil {
+		s.bp.buf = nil
+		s.bp.lock = nil
+		s.bp = nil
+	}
+	s.request = nil
+	s.response = nil
+	s.resch = nil
+}
+
 func (s *stream) Read(buf []byte) (int, error) {
 	if s.closed {
 		return 0, io.EOF