Re: [PATCH v4 3/3] selftest/mm: ksm_functional_tests: extend test case for ksm fork/exec

[David Hildenbrand <david@redhat.com>]

On 28.03.24 12:10, Jinjiang Tu wrote:
> This extends test_prctl_fork() and test_prctl_fork_exec() to make sure
> that deduplication really happens, instead of only testing the
> MMF_VM_MERGE_ANY flag is set.
> 
> Suggested-by: David Hildenbrand <david@redhat.com>
> Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
> ---
>   .../selftests/mm/ksm_functional_tests.c       | 49 ++++++++++++++-----
>   1 file changed, 38 insertions(+), 11 deletions(-)
> 
> diff --git a/tools/testing/selftests/mm/ksm_functional_tests.c b/tools/testing/selftests/mm/ksm_functional_tests.c
> index 5462873df84c..2d277620fad2 100644
> --- a/tools/testing/selftests/mm/ksm_functional_tests.c
> +++ b/tools/testing/selftests/mm/ksm_functional_tests.c
> @@ -475,6 +475,36 @@ static void test_prctl(void)
>   	ksft_test_result_pass("Setting/clearing PR_SET_MEMORY_MERGE works\n");
>   }
>   
> +static int test_child_ksm(void)
> +{
> +	const unsigned int size = 2 * MiB;
> +	char *map;
> +
> +	/* Test if KSM is enabled for the process. */
> +	if (prctl(PR_GET_MEMORY_MERGE, 0, 0, 0, 0) != 1)
> +		return -1;
> +
> +	/* Test if merge could really happen. */
> +	map = __mmap_and_merge_range(0xcf, size, PROT_READ | PROT_WRITE, KSM_MERGE_NONE);
> +	if (map == MAP_MERGE_FAIL)
> +		return -2;
> +	else if (map == MAP_MERGE_SKIP)
> +		return -3;
> +
> +	munmap(map, size);
> +	return 0;
> +}
> +
> +static void test_child_ksm_err(int status)

Maybe better "handle_child_ksm_err" because you only call it if status != 0.


Thanks!

Reviewed-by: David Hildenbrand <david@redhat.com>


-- 
Cheers,

David / dhildenb