Re: [PATCH v3 31/54] selftests/mm: cow: add setup of HugeTLB pages

[Sarthak Sharma]

Hi Mike!

On 4/29/26 2:12 AM, Mike Rapoport wrote:
> From: "Mike Rapoport (Microsoft)" <rppt@xxxxxxxxxx>
> 
> cow tests skips HugeTLB tests if there are no free huge pages prepared
> by a wrapper script.
> 
> Add setup of HugeTLB pages to the test and make sure that the original
> settings are restored on the test exit.
> 
> Signed-off-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
> ---
>  tools/testing/selftests/mm/cow.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/testing/selftests/mm/cow.c b/tools/testing/selftests/mm/cow.c
> index 4321f4208fe3..1df513bf362d 100644
> --- a/tools/testing/selftests/mm/cow.c
> +++ b/tools/testing/selftests/mm/cow.c
> @@ -1881,21 +1881,21 @@ int main(int argc, char **argv)
>  
>  	ksft_print_header();
>  
> +	hugepage_save_settings(true, true);

Since hugetlb_setup below already calls hugepage_save_settings()
internally, perhaps we can change this to hugepage_save_settings(true,
false) or simply keep thp_save_settings()? Otherwise we're saving the
HugeTLB state twice here and it seems redundant.

> +
>  	pagesize = getpagesize();
>  	pmdsize = read_pmd_pagesize();
>  	if (pmdsize) {
>  		/* Only if THP is supported. */
>  		thp_read_settings(&default_settings);
>  		default_settings.hugepages[sz2ord(pmdsize, pagesize)].enabled = THP_INHERIT;
> -		thp_save_settings();
>  		thp_push_settings(&default_settings);
>  
>  		ksft_print_msg("[INFO] detected PMD size: %zu KiB\n",
>  			       pmdsize / 1024);
>  		nr_thpsizes = detect_thp_sizes(thpsizes, ARRAY_SIZE(thpsizes));
>  	}
> -	nr_hugetlbsizes = detect_hugetlb_page_sizes(hugetlbsizes,
> -						    ARRAY_SIZE(hugetlbsizes));
> +	nr_hugetlbsizes = hugetlb_setup(2, hugetlbsizes, ARRAY_SIZE(hugetlbsizes));
>  	has_huge_zeropage = detect_huge_zeropage();
>  
>  	ksft_set_plan(ARRAY_SIZE(anon_test_cases) * tests_per_anon_test_case() +