[PATCH v9 1/6] selftests/resctrl: Fix set up schemata with 100% allocation on first run in MBM test

From: Shaopeng Tan
Date: Thu Apr 13 2023 - 03:23:09 EST


There is a comment "Set up shemata with 100% allocation on the first run"
in function mbm_setup(), but there is an increment bug and the condition
"num_of_runs == 0" will never be met and write_schemata() will never be
called to set schemata to 100%. Even if write_schemata() is called in MBM
test, since it is not supported for MBM test it does not set the schemata.
This is currently fine because resctrl_val_parm->mum_resctrlfs is always 1
and umount/mount will be run in each test to set the schemata to 100%.

To support the usage when MBM test does not unmount/remount resctrl
filesystem before the test starts, fix to call write_schemata() and
set schemata properly when the function is called for the first time.

Also, remove static local variable 'num_of_runs' because this is not
needed as there is resctrl_val_param->num_of_runs which should be used
instead like in cat_setup().

Reviewed-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Signed-off-by: Shaopeng Tan <tan.shaopeng@xxxxxxxxxxxxxx>
---
tools/testing/selftests/resctrl/mbm_test.c | 13 +++++++------
tools/testing/selftests/resctrl/resctrlfs.c | 4 +++-
2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/tools/testing/selftests/resctrl/mbm_test.c b/tools/testing/selftests/resctrl/mbm_test.c
index c9dfa54af42f..9b591c35310f 100644
--- a/tools/testing/selftests/resctrl/mbm_test.c
+++ b/tools/testing/selftests/resctrl/mbm_test.c
@@ -89,23 +89,24 @@ static int check_results(int span)
static int mbm_setup(int num, ...)
{
struct resctrl_val_param *p;
- static int num_of_runs;
va_list param;
int ret = 0;

- /* Run NUM_OF_RUNS times */
- if (num_of_runs++ >= NUM_OF_RUNS)
- return END_OF_TESTS;
-
va_start(param, num);
p = va_arg(param, struct resctrl_val_param *);
va_end(param);

+ /* Run NUM_OF_RUNS times */
+ if (p->num_of_runs >= NUM_OF_RUNS)
+ return -1;
+
/* Set up shemata with 100% allocation on the first run. */
- if (num_of_runs == 0)
+ if (p->num_of_runs == 0)
ret = write_schemata(p->ctrlgrp, "100", p->cpu_no,
p->resctrl_val);

+ p->num_of_runs++;
+
return ret;
}

diff --git a/tools/testing/selftests/resctrl/resctrlfs.c b/tools/testing/selftests/resctrl/resctrlfs.c
index cc6cf49e3129..b31b1d9e41d1 100644
--- a/tools/testing/selftests/resctrl/resctrlfs.c
+++ b/tools/testing/selftests/resctrl/resctrlfs.c
@@ -498,6 +498,7 @@ int write_schemata(char *ctrlgrp, char *schemata, int cpu_no, char *resctrl_val)
FILE *fp;

if (strncmp(resctrl_val, MBA_STR, sizeof(MBA_STR)) &&
+ strncmp(resctrl_val, MBM_STR, sizeof(MBM_STR)) &&
strncmp(resctrl_val, CAT_STR, sizeof(CAT_STR)) &&
strncmp(resctrl_val, CMT_STR, sizeof(CMT_STR)))
return -ENOENT;
@@ -523,7 +524,8 @@ int write_schemata(char *ctrlgrp, char *schemata, int cpu_no, char *resctrl_val)
if (!strncmp(resctrl_val, CAT_STR, sizeof(CAT_STR)) ||
!strncmp(resctrl_val, CMT_STR, sizeof(CMT_STR)))
sprintf(schema, "%s%d%c%s", "L3:", resource_id, '=', schemata);
- if (!strncmp(resctrl_val, MBA_STR, sizeof(MBA_STR)))
+ if (!strncmp(resctrl_val, MBA_STR, sizeof(MBA_STR)) ||
+ !strncmp(resctrl_val, MBM_STR, sizeof(MBM_STR)))
sprintf(schema, "%s%d%c%s", "MB:", resource_id, '=', schemata);

fp = fopen(controlgroup, "w");
--
2.27.0