How to minimize the code size of peer manager?(SDK12, S130)

Hi Nordic, I started from an empty project with peripherial control first, the code size is about 12KB. Then after adding peer manager and related code(fstorage, fds and etc.), the code size become 27KB.In order not to reach the code size 32KB limitation of KEIL. Please kindly tell me how to simplify the extra 15KB size usage of peer manager. Thanks.