busdma buffer management enhancements - call for review and test

[Adrian Chadd]

I just want to make sure that you don't assume individual memory
access costs are the same regardless of how big the allocations are.

Ie, if you have a bunch of scattered L1-sized allocations, versus them
all being nearby in the same 512/1024 byte page; the underlying memory
architecture may be doing memory transactions at a slightly larger
size than your L1 assumption.

Damn these hierarchicial memory systems.


Adrian