Re: [PATCH v3 2/5] selftests/resctrl: Add helpers for the non-contiguous test

Hi Maciej,

On 1/25/2024 3:10 AM, Maciej Wieczor-Retman wrote:

The CAT non-contiguous selftests have to read the file responsible for reporting support of non-contiguous CBMs in kernel (resctrl). Then the test compares if that information matches what is reported by CPUID output.

Add a generic helper function to read an unsigned number from a file in /sys/fs/resctrl/info/<RESOURCE>/<FILE>.

Signed-off-by: Maciej Wieczor-Retman maciej.wieczor-retman@intel.com

Changelog v3:

• Rewrite patch message.
• Add documentation and rewrote the function. (Reinette)

Changelog v2:

• Add this patch.

tools/testing/selftests/resctrl/resctrl.h | 1 + tools/testing/selftests/resctrl/resctrlfs.c | 39 +++++++++++++++++++++ 2 files changed, 40 insertions(+)

diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/selftests/resctrl/resctrl.h index a1462029998e..5116ea082d03 100644 --- a/tools/testing/selftests/resctrl/resctrl.h +++ b/tools/testing/selftests/resctrl/resctrl.h @@ -162,6 +162,7 @@ unsigned int count_contiguous_bits(unsigned long val, unsigned int *start); int get_full_cbm(const char *cache_type, unsigned long *mask); int get_mask_no_shareable(const char *cache_type, unsigned long *mask); int get_cache_size(int cpu_no, const char *cache_type, unsigned long *cache_size); +int resource_info_unsigned_get(const char *resource, const char *filename, unsigned int *val); void ctrlc_handler(int signum, siginfo_t *info, void *ptr); int signal_handler_register(void); void signal_handler_unregister(void); diff --git a/tools/testing/selftests/resctrl/resctrlfs.c b/tools/testing/selftests/resctrl/resctrlfs.c index 5750662cce57..cb5147c5f9a9 100644 --- a/tools/testing/selftests/resctrl/resctrlfs.c +++ b/tools/testing/selftests/resctrl/resctrlfs.c @@ -249,6 +249,45 @@ static int get_bit_mask(const char *filename, unsigned long *mask) return 0; } +/*

By not starting with /** the following will not be interpreted as kernel-doc but the formatting does appear to follow the syntax, but not consistently so. I think it would be more readable if the kernel-doc syntax is followed consistently.

• • resource_info_unsigned_get - Read an unsigned value from a file in
• • /sys/fs/resctrl/info/RESOURCE/FILENAME

"Read an unsigned value from /sys/fs/resctrl/info/RESOURCE/FILENAME"?

• • @resource: Resource name that matches directory names in

names? (plural)

• • /sys/fs/resctrl/info
    

• • @filename: Filename of a file located in a directory specified with the

• • 'resource' variable.
    

I think this can be shortened to "File in /sys/fs/resctrl/info/@resource"

• • @val: Variable where the read value is saved on success.

"Contains read value on success."

(no need to refer to it as a variable/parameter, it is implied by syntax).

• • Return: = 0 on success, < 0 on failure. On success the read value is saved into the 'val'
• • variable.

"saved into the 'val' variable" -> "saved into @val" (since syntax indicates it is the parameter there is no need to elaborate). Also please let lines in comments be of consistent length.

• */

+int resource_info_unsigned_get(const char *resource, const char *filename,

• 	       unsigned int *val)
  

+{

• char reason[128], file_path[PATH_MAX];
• FILE *fp;
• snprintf(file_path, sizeof(file_path), "%s/%s/%s", INFO_PATH, resource,

•  filename);
  

• fp = fopen(file_path, "r");
• if (!fp) {

• snprintf(reason, sizeof(reason), "Error in opening %s file\n", filename);
  

(apart from other discussions). "file" in message seems redundant. It can just be "Error opening %s". It may also be useful to print file_path instead of filename to be specific of what the code tried to open.

• ksft_perror(reason);
  

• return -1;
  

• }
• if (fscanf(fp, "%u", val) <= 0) {

• snprintf(reason, sizeof(reason), "Could not get %s's contents\n", filename);
  

• ksft_perror(reason);
  

filename -> file_path ?

• fclose(fp);
  

• return -1;
  

• }
• fclose(fp);
• return 0;

+}

Reinette