> Aggressive use of TRIM when committing entries out of the journal would
> make it easier to reap blocks within this faster level of hierarchy, and
> would make the drive less sensitive to the size of the journal. That is,
> the journal could be much larger than the NVRAM size, but you'd still get
> the benefit if the *active* part of the journal fit in the NVRAM.
Aggressive use of TRIM on the journal could also mean TRIMming the journal completely on a clean mount, or even after replaying it on an unclean mount (some care needs to be taken here, though). I think this could help wear leveling on laptops and netbooks quite a bit (they boot often), and those are currently the place where the biggest advantages of SSDs are.