linux-master/mm/readahead.c

29  * contains ->size being the total number of pages, and ->async_size
102  * Those folios not in the final ``async_size`` of the request should be
106  * become available.  Folios in the final ``async_size`` may be
171 			if (rac->ra->async_size >= nr) {
172 				rac->ra->async_size -= nr;
379  *                        |<----- async_size ---------|
388  * only async_size pages left in the readahead window. Normally async_size
393  * page at (start+size-async_size) with PG_readahead, and use it as readahead
459 	ra->async_size = 1;
492 	pgoff_t mark = index + ra->size - ra->async_size;
525 		ra->async_size += index - limit - 1;
539 	do_page_cache_ra(ractl, ra->size, ra->async_size);
573 	expected = round_down(ra->start + ra->size - ra->async_size,
578 		ra->async_size = ra->size;
585 	 * Query the pagecache for async_size, which normally equals to
600 		ra->size = start - index;	/* old async_size */
603 		ra->async_size = ra->size;
640 	ra->async_size = ra->size > req_size ? ra->size - req_size : ra->size;
649 	if (index == ra->start && ra->size == ra->async_size) {
652 			ra->async_size = add_pages;
656 			ra->async_size = max_pages >> 1;
831 			ra->async_size++;