diff --git a/session.go b/session.go
index 79441e1..bf5f680 100644
--- a/session.go
+++ b/session.go
@@ -21,15 +21,15 @@ import (
 // The MemoryManager allows management of memory allocations.
 type MemoryManager interface {
 	// ReserveMemory reserves memory / buffer.
-	ReserveMemory(size int, prio uint8) error
+	ReserveMemory(conn *Session, size int, prio uint8) error
 	// ReleaseMemory explicitly releases memory previously reserved with ReserveMemory
-	ReleaseMemory(size int)
+	ReleaseMemory(conn *Session, size int)
 }
 
 type nullMemoryManagerImpl struct{}
 
-func (n nullMemoryManagerImpl) ReserveMemory(size int, prio uint8) error { return nil }
-func (n nullMemoryManagerImpl) ReleaseMemory(size int)                   {}
+func (n nullMemoryManagerImpl) ReserveMemory(conn *Session, size int, prio uint8) error { return nil }
+func (n nullMemoryManagerImpl) ReleaseMemory(conn *Session, size int)                   {}
 
 var nullMemoryManager MemoryManager = &nullMemoryManagerImpl{}
 
@@ -208,7 +208,7 @@ func (s *Session) OpenStream(ctx context.Context) (*Stream, error) {
 		return nil, s.shutdownErr
 	}
 
-	if err := s.memoryManager.ReserveMemory(initialStreamWindow, 255); err != nil {
+	if err := s.memoryManager.ReserveMemory(s, initialStreamWindow, 255); err != nil {
 		return nil, err
 	}
 
@@ -759,7 +759,7 @@ func (s *Session) incomingStream(id uint32) error {
 	}
 
 	// Allocate a new stream
-	if err := s.memoryManager.ReserveMemory(initialStreamWindow, 255); err != nil {
+	if err := s.memoryManager.ReserveMemory(s, initialStreamWindow, 255); err != nil {
 		return err
 	}
 	stream := newStream(s, id, streamSYNReceived, initialStreamWindow)
@@ -773,14 +773,14 @@ func (s *Session) incomingStream(id uint32) error {
 		if sendErr := s.sendMsg(s.goAway(goAwayProtoErr), nil, nil); sendErr != nil {
 			s.logger.Printf("[WARN] yamux: failed to send go away: %v", sendErr)
 		}
-		s.memoryManager.ReleaseMemory(initialStreamWindow)
+		s.memoryManager.ReleaseMemory(s, initialStreamWindow)
 		return ErrDuplicateStream
 	}
 
 	if s.numIncomingStreams >= s.config.MaxIncomingStreams {
 		// too many active streams at the same time
 		s.logger.Printf("[WARN] yamux: MaxIncomingStreams exceeded, forcing stream reset")
-		s.memoryManager.ReleaseMemory(initialStreamWindow)
+		s.memoryManager.ReleaseMemory(s, initialStreamWindow)
 		hdr := encode(typeWindowUpdate, flagRST, id, 0)
 		return s.sendMsg(hdr, nil, nil)
 	}
@@ -827,7 +827,7 @@ func (s *Session) deleteStream(id uint32) {
 	if !ok {
 		return
 	}
-	s.memoryManager.ReleaseMemory(int(str.recvWindow))
+	s.memoryManager.ReleaseMemory(s, int(str.recvWindow))
 	delete(s.streams, id)
 }
 
diff --git a/stream.go b/stream.go
index 7ae0be3..bbc40de 100644
--- a/stream.go
+++ b/stream.go
@@ -225,7 +225,7 @@ func (s *Stream) sendWindowUpdate() error {
 			recvWindow = min(s.recvWindow*2, s.session.config.MaxStreamWindowSize)
 		}
 		if recvWindow > s.recvWindow {
-			if err := s.session.memoryManager.ReserveMemory(int(delta), 128); err == nil {
+			if err := s.session.memoryManager.ReserveMemory(s.session, int(delta), 128); err == nil {
 				s.recvWindow = recvWindow
 				_, delta = s.recvBuf.GrowTo(s.recvWindow, true)
 			}