balloon_free_pages
if ((r = balloon_free_pages(1, &mfn, NULL, NULL)) != 1) {
extern long balloon_free_pages(uint_t, mfn_t *, caddr_t, pfn_t *);
(void) balloon_free_pages(rv - cnt, &mfn_frames[i], NULL, NULL);
rv = balloon_free_pages(debit, mfn_frames, NULL, NULL);
cnt = balloon_free_pages(1, NULL, NULL, &pp[i]->p_pagenum);
long balloon_free_pages(uint_t, mfn_t *, caddr_t, pfn_t *);