RDS: add stat for socket recv memory usage

Tracks the receive side memory added to scokets and removed from sockets.

Signed-off-by: Venkat Venkatsubra <venkat.x.venkatsubra@oracle.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
diff --git a/net/rds/rds.h b/net/rds/rds.h
index 0bb8213..8ccd5a9 100644
--- a/net/rds/rds.h
+++ b/net/rds/rds.h
@@ -631,6 +631,9 @@ struct rds_statistics {
 	uint64_t	s_cong_update_received;
 	uint64_t	s_cong_send_error;
 	uint64_t	s_cong_send_blocked;
+	uint64_t	s_recv_bytes_added_to_socket;
+	uint64_t	s_recv_bytes_removed_from_socket;
+
 };
 
 /* af_rds.c */