Re: [PATCH v6 3/3] kselftest: mm: remove check_huge_shmem()

["David Hildenbrand (Arm)" <david@kernel.org>]

On 9/14/26 09:30, Yeoreum Yun wrote:
> check_huge_shmem() was required to distinguish shmem huge pages because
> /proc/self/smaps reports them using a dedicated “ShmemPmdMapped” entry,
> as opposed to “FilePmdMapped” for file-backed huge pages.
> 
> Now that /proc/self/smaps is no longer used to detect huge pages and
> /proc/kpageflags is used instead, it is sufficient to distinguish
> between file-backed and anonymous pages since the ShmemPmdMapped is also
> kind of file-backed.
> 
> Therefore, remove check_huge_shmem() and use check_huge_file() instead.
> 
> Suggested-by: David Hildenbrand (Arm) <david@kernel.org>
> Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
> ---
>  tools/testing/selftests/mm/folio_split_race_test.c |  2 +-
>  tools/testing/selftests/mm/khugepaged.c            |  5 ++---
>  tools/testing/selftests/mm/uffd-common.c           |  4 ++--
>  tools/testing/selftests/mm/vm_util.c               | 11 +----------
>  tools/testing/selftests/mm/vm_util.h               |  2 --
>  5 files changed, 6 insertions(+), 18 deletions(-)
> 
> diff --git a/tools/testing/selftests/mm/folio_split_race_test.c b/tools/testing/selftests/mm/folio_split_race_test.c
> index 1960635a953e..4c0d3b6a411b 100644
> --- a/tools/testing/selftests/mm/folio_split_race_test.c
> +++ b/tools/testing/selftests/mm/folio_split_race_test.c
> @@ -182,7 +182,7 @@ static uint64_t run_iteration(void)
>  	for (i = 0; i < TOTAL_PAGES; i++)
>  		fill_page(mmap_base, i);
>  
> -	if (!check_huge_shmem(mmap_base, FILE_SIZE, NR_PMD_PAGE, pmd_pagesize))
> +	if (!check_huge_file(mmap_base, FILE_SIZE, NR_PMD_PAGE, pmd_pagesize))
>  		ksft_exit_fail_msg("No shmem THP is allocated\n");
>  
>  	if (pthread_barrier_init(&ctl.barrier, NULL, NUM_READER_THREADS + 1) != 0)
> diff --git a/tools/testing/selftests/mm/khugepaged.c b/tools/testing/selftests/mm/khugepaged.c
> index f82673f5f6b4..6cd1effea465 100644
> --- a/tools/testing/selftests/mm/khugepaged.c
> +++ b/tools/testing/selftests/mm/khugepaged.c
> @@ -416,9 +416,8 @@ static bool file_check_huge(void *addr, size_t len, int nr_hpages,
>  {
>  	switch (finfo.type) {
>  	case VMA_FILE:
> -		return check_huge_file(addr, len, nr_hpages, hpage_size);
>  	case VMA_SHMEM:
> -		return check_huge_shmem(addr, len, nr_hpages, hpage_size);
> +		return check_huge_file(addr, len, nr_hpages, hpage_size);
>  	default:
>  		ksft_exit_fail_msg("Unknown VMA type\n");
>  		return false;


Assuming we do:

diff --git a/tools/testing/selftests/mm/khugepaged.c b/tools/testing/selftests/mm/khugepaged.c
index f82673f5f6b47..9542173a748e2 100644
--- a/tools/testing/selftests/mm/khugepaged.c
+++ b/tools/testing/selftests/mm/khugepaged.c
@@ -53,7 +53,7 @@ struct mem_ops {
        void *(*setup_area)(int nr_hpages);
        void (*cleanup_area)(void *p, unsigned long size);
        void (*fault)(void *p, unsigned long start, unsigned long end);
-       bool (*check_huge)(void *addr, size_t len, int nr_hpages, unsigned long hpage_size);
+       bool (*check_huge)(void *addr, size_t len, int nr_hpages, uint64_t hpage_size);
        const char *name;
 };


Could we then simply use check_huge_anon/check_huge_file directly and get rid of
these helpers anon_check_huge + check_huge_file entirely?

-- 
Cheers,

David