pageref           171 kern/vm/kmalloc.c freepageref(struct pageref *p)
pageref           212 kern/vm/kmalloc.c checksubpage(struct pageref *pr)
pageref           284 kern/vm/kmalloc.c dumpsubpage(struct pageref *pr)
pageref           354 kern/vm/kmalloc.c remove_lists(struct pageref *pr, int blktype)