Function vm_object_terminate_pages

freebsd/vm/vm_object.c:879–917

* vm_object_terminate_pages removes any remaining pageable pages * from the object and resets the object to an empty state. */

 *	from the object and resets the object to an empty state.
 */
static void
vm_object_terminate_pages(vm_object_t object)
{
	vm_page_t p, p_next;

	VM_OBJECT_ASSERT_WLOCKED(object);

	/*
	 * Free any remaining pageable pages.  This also removes them from the
	 * paging queues.  However, don't free wired pages, just remove them
	 * from the object.  Rather than incrementally removing each page from
	 * the object, the page and object are reset to any empty state. 
	 */
	TAILQ_FOREACH_SAFE(p, &object->memq, listq, p_next) {
		vm_page_assert_unbusied(p);
		KASSERT(p->object == object &&
		    (p->ref_count & VPRC_OBJREF) != 0,
		    ("vm_object_terminate_pages: page %p is inconsistent", p));

		p->object = NULL;
		if (vm_page_drop(p, VPRC_OBJREF) == VPRC_OBJREF) {
			VM_CNT_INC(v_pfree);
			vm_page_free(p);
		}
	}

	/*
	 * If the object contained any pages, then reset it to an empty state.
	 * None of the object's fields, including "resident_page_count", were
	 * modified by the preceding loop.
	 */
	if (object->resident_page_count != 0) {
		vm_radix_reclaim_allnodes(&object->rtree);
		TAILQ_INIT(&object->memq);
		object->resident_page_count = 0;
		if (object->type == OBJT_VNODE)
			vdrop(object->handle);
	}
}

/*
 *	vm_object_terminate actually destroys the specified object, freeing