vm_object_allocate_hold
object = vm_object_allocate_hold(tp, pindex);
object = vm_object_allocate_hold(OBJT_DEFAULT,
result = vm_object_allocate_hold(OBJT_DEFAULT, length);
vm_object_t vm_object_allocate_hold (objtype_t, vm_pindex_t);
object = vm_object_allocate_hold(OBJT_VNODE, lsize);