[PATCH v2 1/4] selftests/resctrl: Fix set up shemata with 100% allocation on first run in MBM test.

From: Shaopeng Tan
Date: Tue Oct 04 2022 - 21:43:47 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%. This is currently fine because
resctl_val_parm->num_resctrlfs is always 1 and umount/mount will be run
in each test to set the schemata to 100%.

To make mbm_setup() future code-change proof, fix to call
write-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 resctl_val_param->num_of_runs which should be used
instead like in cat_setup().

Signed-off-by: Shaopeng Tan <tan.shaopeng@xxxxxxxxxxxxxx>
---
tools/testing/selftests/resctrl/mbm_test.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/resctrl/mbm_test.c b/tools/testing/selftests/resctrl/mbm_test.c
index 8392e5c55ed0..4a54be314402 100644
--- a/tools/testing/selftests/resctrl/mbm_test.c
+++ b/tools/testing/selftests/resctrl/mbm_test.c
@@ -89,12 +89,11 @@ 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)
+ if (p->num_of_runs >= NUM_OF_RUNS)
return -1;

va_start(param, num);
@@ -102,9 +101,10 @@ static int mbm_setup(int num, ...)
va_end(param);

/* 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;
}
--
2.27.0