/* Assumption: *_mem_map is contiguous at least up to MAX_ORDER  */
static struct page* __page_find_buddy(struct page *page, unsigned long page_idx, unsigned int order)
/* Assumption: *_mem_map is contiguous at least up to MAX_ORDER  */
static struct page* __page_find_buddy(struct page *page, unsigned long page_idx, unsigned int order)
{
	unsigned long buddy_idx = page_idx ^ (1 << order);
	return page + (buddy_idx - page_idx);
}