Just in case: do you know that 'em stands for 'them' ?

Knowing the context of the song would help... usually in song writing as in poetry, the 'meaning' is determined by the reader/listener. It could mean - eg: literally- that there is no place to keep (what ever is being refered to) in his/her place (apartment, room, storage area) that is in the 'uptown' area of the city or eg: figuritively (metaphor) as in: 'no room left in his brain (uptown) for more thoughts ('em)' or there is no way to keep the elements of his/her style ('em) in a classy manner (uptown) as in 'Keeping it uptown!' Good luck with this Ahhsin, song lyrics are always difficult to interpet!

It's art, so a person may interpret the lyrics according to his or her own thinking. For me, it means that he no longer has a place for old memories in his current life. He has moved on.