Joining Royal Caribean Cruise at Baoshan Cruise terminal...

We are from Malaysia, will be traveling under the 15 days visa free option. After 12 days, we will join the Royal Caribbean cruise to Japan for 5N6D, back to Shanghai again. Is joining the cruise considered as exit China? Coming to Shanghai again after the cruise is consider as new entry to China, and enjoy another 15 days visa free option? Thank you.