>> Compatiblity with Mach VM: clear pmap-private bits in pmap_remove() if !UVM.


>"referenced" and "modifed" are attributes of the hardware page, not the
>mapping of it.

Exactly so. The VM system should track them as PG_CLEAN and not mess
around with the clean or referenced bits when mappings get removed.
(That goes for UVM, too.)


Castor Fu says the previous tieration doesn't work anymore with the
old Mach VM.  What should we do?  Go back to frobbing PG_CLEAN directly?