Re: [Patch v2] selftests/mm: do check_huge_anon() with a number been passed in

[Donet Tom]

On 8/10/25 1:12 AM, Wei Yang wrote:

Currently it hard codes the number of hugepage to check for
check_huge_anon(), but it would be more reasonable to do the check based
on a number passed in.

Pass in the hugepage number and do the check based on it.

Signed-off-by: Wei Yang <richard.weiy...@gmail.com>
Cc: Baolin Wang <baolin.w...@linux.alibaba.com>
Cc: Donet Tom <donet...@linux.ibm.com>
Cc: David Hildenbrand <da...@redhat.com>
Cc: Dev Jain <dev.j...@arm.com>
Cc: Lorenzo Stoakes <lorenzo.stoa...@oracle.com>
Cc: Zi Yan <z...@nvidia.com>

---
v2:
   * use mm-new
   * add back nr_hpages which is removed by an early commit
   * adjust the change log a little
   * drop RB and resend
---
  tools/testing/selftests/mm/split_huge_page_test.c | 6 +++---
  1 file changed, 3 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 5ab488fab1cd..63ac82f0b9e0 100644
--- a/tools/testing/selftests/mm/split_huge_page_test.c
+++ b/tools/testing/selftests/mm/split_huge_page_test.c
@@ -105,12 +105,12 @@ static char *allocate_zero_filled_hugepage(size_t len)
        return result;
  }

-static void verify_rss_anon_split_huge_page_all_zeroes(char *one_page, size_t len)

+static void verify_rss_anon_split_huge_page_all_zeroes(char *one_page, int 
nr_hpages, size_t len)

We are re-adding this argument because nr_hpages should be the same in both
split_pmd_zero_pages and verify_rss_anon_split_huge_page_all_zeroes,
correct? I was just wondering — since the value is currently hardcoded
in both functions, would it be preferable to pass it as an argument,
or keep it hardcoded, What benefit do we gain by re-adding this argument?

  {
        unsigned long rss_anon_before, rss_anon_after;
        size_t i;

- if (!check_huge_anon(one_page, 4, pmd_pagesize))

+       if (!check_huge_anon(one_page, nr_hpages, pmd_pagesize))
                ksft_exit_fail_msg("No THP is allocated\n");

rss_anon_before = rss_anon();

@@ -141,7 +141,7 @@ void split_pmd_zero_pages(void)
        size_t len = nr_hpages * pmd_pagesize;

one_page = allocate_zero_filled_hugepage(len);

-       verify_rss_anon_split_huge_page_all_zeroes(one_page, len);
+       verify_rss_anon_split_huge_page_all_zeroes(one_page, nr_hpages, len);
        ksft_test_result_pass("Split zero filled huge pages successful\n");
        free(one_page);
  }