On 29 Aug 2025, at 22:31, Wei Yang wrote:
> The check of is_backed_by_folio() is done on each page.
>
> Directly move pointer to next page instead of increase one and check if
> it is page size aligned.
>
> Signed-off-by: Wei Yang <[email protected]>
> ---
> tools/testing/selftests/mm/split_huge_page_test.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/tools/testing/selftests/mm/split_huge_page_test.c
> b/tools/testing/selftests/mm/split_huge_page_test.c
> index 10ae65ea032f..7f7016ba4054 100644
> --- a/tools/testing/selftests/mm/split_huge_page_test.c
> +++ b/tools/testing/selftests/mm/split_huge_page_test.c
> @@ -423,9 +423,8 @@ static void split_pte_mapped_thp(void)
>
> /* smap does not show THPs after mremap, use kpageflags instead */
> thp_size = 0;
> - for (i = 0; i < pagesize * 4; i++)
> - if (i % pagesize == 0 &&
> - is_backed_by_folio(&pte_mapped[i], pmd_order, pagemap_fd,
> kpageflags_fd))
> + for (i = 0; i < pagesize * 4; i += pagesize)
> + if (is_backed_by_folio(&pte_mapped[i], pmd_order, pagemap_fd,
> kpageflags_fd))
> thp_size++;
>
> if (thp_size != 4)
It might be better to add
if (pte_mapped[i] != (char)i)
ksft_exit_fail_msg("%ld byte corrupted\n", i);
instead to make sure mremap() does not change pte_mapped[] values.
--
Best Regards,
Yan, Zi
