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

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Date:   Fri, 14 Apr 2023 15:31:55 +0300 (EEST)
From:   Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To:     Shaopeng Tan <tan.shaopeng@...fujitsu.com>
cc:     Fenghua Yu <fenghua.yu@...el.com>,
        Reinette Chatre <reinette.chatre@...el.com>,
        Shuah Khan <shuah@...nel.org>, linux-kernel@...r.kernel.org,
        linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v9 1/6] selftests/resctrl: Fix set up schemata with 100%
 allocation on first run in MBM test

On Thu, 13 Apr 2023, Shaopeng Tan wrote:

> There is a comment "Set up shemata with 100% allocation on the first run"

s/shemata/schemata/

> 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@...el.com>
> Signed-off-by: Shaopeng Tan <tan.shaopeng@...fujitsu.com>
> ---
>  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;

This is not rebased correctly, negative return values mean now errors.
To complete tests "normally", return END_OF_TESTS. Please see commit 
fa10366cc6f4 ("selftests/resctrl: Allow ->setup() to return errors") for 
future information.

With the forementioned problems fixed:

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>

-- 
 i.

> +
>  	/* 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");
>