mm: fix PSWPIN counter for large folios swap-in

Similar to PSWPOUT, we should count the number of base pages instead of
large folios.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 242d12c ("mm: support large folios swap-in for sync io devices")
Signed-off-by: Barry Song <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Reviewed-by: Baolin Wang <[email protected]>
Cc: Chris Li <[email protected]>
Cc: Yosry Ahmed <[email protected]>
Cc: "Huang, Ying" <[email protected]>
Cc: Kairui Song <[email protected]>
Cc: Ryan Roberts <[email protected]>
Cc: Kanchana P Sridhar <[email protected]>
Cc: Usama Arif <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: Barry Song

mm/page_io.c

@@ -570,7 +570,7 @@ static void swap_read_folio_bdev_sync(struct folio *folio,
 	 * attempt to access it in the page fault retry time check.
 	 */
 	get_task_struct(current);
-	count_vm_event(PSWPIN);
+	count_vm_events(PSWPIN, folio_nr_pages(folio));
 	submit_bio_wait(&bio);
 	__end_swap_bio_read(&bio);
 	put_task_struct(current);
@@ -585,7 +585,7 @@ static void swap_read_folio_bdev_async(struct folio *folio,
 	bio->bi_iter.bi_sector = swap_folio_sector(folio);
 	bio->bi_end_io = end_swap_bio_read;
 	bio_add_folio_nofail(bio, folio, folio_size(folio), 0);
-	count_vm_event(PSWPIN);
+	count_vm_events(PSWPIN, folio_nr_pages(folio));
 	submit_bio(bio);
 }