Tim Bisson has inital TRIM support working for UFS. His lengthy posting talks about how it’s done, and shows how much it speeds things up. He’s looking for testers, so please try it if you have a SSD. (The usual warnings apply about testing code that specifically deletes things.)
For those not familiar with TRIM in SSD context, here’s the least annoying page with an explanation that I could find in a few seconds of Googling.