4mb PAGES for mbuf clusters

[Matthew Dillon]

    It's not a bad idea and tests done on FreeBSD have shown a
    significant improvement in performance for certain workloads,
    but it's fairly difficult to manage memory in 4MB chunks
    and fragmentation will screw it up on machines with long uptimes,
    so unless we rewrite a whole lot of subsystems I don't think we
    can do better then a hack.  For the record, I don't like what FreeBSD
    did.

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>