A woman living in hotel walls, dressing as a biker killing people?

I remember watching a film where there was a junk sale/market/swap meet type thing in a disused swimming pool in a hotel (abandoned hotel?) I thought I dreamt it but I've found a message to a friend saying I was watching a weird film with an Asian woman living in hotel walls who goes round killing people while dressed as a biker (I'm guessing maybe she wears a bike helmet so no one can see who she is) The swimming pool bit may have homeless people living there trading their stuff. 

Any ideas? I sent the message in Dec 21 so the film was released prior to that, not that that is much help!