Re: [PATCH v2 2/4] selftests/mm: Add helper for logging test start and results

[David Hildenbrand <david@redhat.com>]

On 27.05.25 18:04, Mark Brown wrote:
> Several of the MM tests have a pattern of printing a description of the
> test to be run then reporting the actual TAP result using a generic string
> not connected to the specific test, often in a shared function used by many
> tests. The name reported typically varies depending on the specific result
> rather than the test too. This causes problems for tooling that works with
> test results, the names reported with the results are used to deduplicate
> tests and track them between runs so both duplicated names and changing
> names cause trouble for things like UIs and automated bisection.
> 
> As a first step towards matching these tests better with the expectations
> of kselftest provide helpers which record the test name as part of the
> initial print and then use that as part of reporting a result.
> 
> This is not added as a generic kselftest helper partly because the use of
> a variable to store the test name doesn't fit well with the header only
> implementation of kselftest.h and partly because it's not really an
> intended pattern. Ideally at some point the mm tests that use it will be
> updated to not need it.
> 
> Signed-off-by: Mark Brown <broonie@kernel.org>
> ---
>   tools/testing/selftests/mm/vm_util.h | 20 ++++++++++++++++++++
>   1 file changed, 20 insertions(+)
> 
> diff --git a/tools/testing/selftests/mm/vm_util.h b/tools/testing/selftests/mm/vm_util.h
> index 6effafdc4d8a..4944e4c79051 100644
> --- a/tools/testing/selftests/mm/vm_util.h
> +++ b/tools/testing/selftests/mm/vm_util.h
> @@ -3,6 +3,7 @@
>   #include <stdbool.h>
>   #include <sys/mman.h>
>   #include <err.h>
> +#include <stdarg.h>
>   #include <strings.h> /* ffsl() */
>   #include <unistd.h> /* _SC_PAGESIZE */
>   #include "../kselftest.h"
> @@ -74,6 +75,25 @@ int uffd_register_with_ioctls(int uffd, void *addr, uint64_t len,
>   unsigned long get_free_hugepages(void);
>   bool check_vmflag_io(void *addr);
>   
> +/* These helpers need to be inline to match the kselftest.h idiom. */
> +static char test_name[1024];
> +
> +static inline void log_test_start(const char *name, ...)
> +{
> +	va_list args;
> +	va_start(args, name);
> +
> +	vsnprintf(test_name, sizeof(test_name), name, args);
> +	ksft_print_msg("[RUN] %s\n", test_name);
> +
> +	va_end(args);
> +}
> +
> +static inline void log_test_result(int result)
> +{
> +	ksft_test_result_report(result, "%s\n", test_name);
> +}

Won't win a beauty contest, but should get the job done.

We could allocate the array in log_test_start() and free it in 
log_test_result(). Then, we could assert more easily that we always have 
a log_test_result() follow exactly one log_test_start() etc.

-- 
Cheers,

David / dhildenb