free_heap(mrb_state *mrb, mrb_gc *gc)
{
  mrb_heap_page *page = gc->heaps;
  mrb_heap_page *tmp;
  RVALUE *p, *e;

  while (page) {
    tmp = page;
    page = page->next;
    for (p = objects(tmp), e=p+MRB_HEAP_PAGE_SIZE; p<e; p++) {
      if (p->as.free.tt != MRB_TT_FREE)
        obj_free(mrb, &p->as.basic, TRUE);
    }
    mrb_free(mrb, tmp);
  }
}