sio_read_complete() uses sio->pages to account global PSWPIN vm events, but sio->pages tracks the number of bvec entries (folios), not base pages. For large folios this undercounts compared to the per-memcg path which correctly uses folio_nr_pages(), and compared to the bdev read paths which also use folio_nr_pages(). Use sio->len >> PAGE_SHIFT instead, which gives the correct base page count since sio->len is accumulated via folio_size(folio). Fixes: 6a8c068774ad ("mm/page_io: use a folio in sio_read_complete()") Signed-off-by: David Carlier --- mm/page_io.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/page_io.c b/mm/page_io.c index 63b262f4c5a9..1389cd57ca88 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -497,7 +497,7 @@ static void sio_read_complete(struct kiocb *iocb, long ret) folio_mark_uptodate(folio); folio_unlock(folio); } - count_vm_events(PSWPIN, sio->pages); + count_vm_events(PSWPIN, sio->len >> PAGE_SHIFT); } else { for (p = 0; p < sio->pages; p++) { struct folio *folio = page_folio(sio->bvec[p].bv_page); -- 2.53.0