i think we were talking about different cases..

	pmap_enter (pmap, 0x00010000, pa, ..., big_pagesize);
	pmap_enter (pmap, 0x00010100, pa, ..., small_pagesize);

vs:

	pmap_enter (pmap, 0x00010100, pa, ..., small_pagesize);
	pmap_enter (pmap, 0x00010000, pa, ..., big_pagesize);

i.e., "punching a hole" in a large page vs. overwriting and
consolidating a bunch of finer-grained mappings all at once..

We need to consider both cases.  The ideal case would be to push the
complexity off on upper layers..

						- Bill