uvmspace_dused
vsize_t uvmspace_dused(struct vm_map*, vaddr_t, vaddr_t);
uvmspace_dused(map, *addr, *addr + sz);
uvmspace_dused(map, entry->start, entry->end);
dused += uvmspace_dused(
uvmspace_dused(map, iter->start,
uvmspace_dused(map, iter->start,
vm2->vm_dused += uvmspace_dused(
uvmspace_dused(map, *addr, *addr + sz);