Whoops. There's something wrong with your hint patch. My buildworld
died horribly on a seg-fault and on other issues. Also, I think the
hint-setting optimization you made is broken. You can't just set it to
entry->prev if the vm_map_lookup_entry() fails because first_entry
could be pointing to the last entry in the list causing entry to point
at &map->header and then the hint would point at the first entry in the
list, which is probably wrong.
I am continuing to test your non-hint patch with a buildworld loop. Once
I'm sure it works properly I will revisit the hinting code.
-Matt