Comment 50 for bug 992424

and for the users :

99Sono (nuno-godinhomatos) wrote on 2013-03-03:
missing the option discard in fstab
this is what you should have.

/dev/sda1 / noatime,discard,errors=remount-ro 0 1

and yes, you can optimze a lot more but it's not needed, try this like above, reboot and test TRIM.