fix(dot/network): memory improvement for network buffers (#2233)

dot/network/inbound.go

@@ -15,8 +15,9 @@ func (s *Service) readStream(stream libp2pnetwork.Stream, decoder messageDecoder
 	s.streamManager.logNewStream(stream)
 
 	peer := stream.Conn().RemotePeer()
-	msgBytes := s.bufPool.get()
-	defer s.bufPool.put(msgBytes)
+	buffer := s.bufPool.Get().(*[]byte)
+	defer s.bufPool.Put(buffer)
+	msgBytes := *buffer
 
 	for {
 		n, err := readStream(stream, msgBytes[:])

dot/network/notifications.go

@@ -427,11 +427,11 @@ func (s *Service) readHandshake(stream libp2pnetwork.Stream, decoder HandshakeDe
 	hsC := make(chan *handshakeReader)
 
 	go func() {
-		msgBytes := s.bufPool.get()
-		defer func() {
-			s.bufPool.put(msgBytes)
-			close(hsC)
-		}()
+		defer close(hsC)
+
+		buffer := s.bufPool.Get().(*[]byte)
+		defer s.bufPool.Put(buffer)
+		msgBytes := *buffer
 
 		tot, err := readStream(stream, msgBytes[:])
 		if err != nil {

dot/network/service.go

@@ -107,7 +107,7 @@ type Service struct {
 	host          *host
 	mdns          *mdns
 	gossip        *gossip
-	bufPool       *sizedBufferPool
+	bufPool       *sync.Pool
 	streamManager *streamManager
 
 	notificationsProtocols map[byte]*notificationsProtocol // map of sub-protocol msg ID to protocol info
@@ -181,16 +181,12 @@ func NewService(cfg *Config) (*Service, error) {
 		return nil, err
 	}
 
-	// pre-allocate pool of buffers used to read from streams.
-	// initially allocate as many buffers as likely necessary which is the number of inbound streams we will have,
-	// which should equal the average number of peers times the number of notifications protocols, which is currently 3.
-	preAllocateInPool := cfg.MinPeers * 3
-	poolSize := cfg.MaxPeers * 3
-	if cfg.noPreAllocate { // testing
-		preAllocateInPool = 0
-		poolSize = cfg.MinPeers * 3
+	bufPool := &sync.Pool{
+		New: func() interface{} {
+			b := make([]byte, maxMessageSize)
+			return &b
+		},
 	}
-	bufPool := newSizedBufferPool(preAllocateInPool, poolSize)
 
 	network := &Service{
 		ctx:                    ctx,