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

From: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
To: Fenghua Yu <fenghua.yu@intel.com>,
	Reinette Chatre <reinette.chatre@intel.com>,
	Shuah Khan <shuah@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
	tan.shaopeng@jp.fujitsu.com
Subject: [PATCH v2 1/4] selftests/resctrl: Fix set up shemata with 100% allocation on first run in MBM test.
Date: Wed,  5 Oct 2022 10:39:30 +0900	[thread overview]
Message-ID: <20221005013933.1486054-2-tan.shaopeng@jp.fujitsu.com> (raw)
In-Reply-To: <20221005013933.1486054-1-tan.shaopeng@jp.fujitsu.com>

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@jp.fujitsu.com>
---
 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

