linux-kernel - Re: [PATCH 2/3] selftests/resctrl: Simplify cleanup in ctrl-c handler

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Message-ID: <uck6k4upde5642uarjjyoeyt76ju7f3ympqbnugnv3ufaw65k2@wdh2chxqsooo>
Date: Tue, 20 Feb 2024 15:08:03 +0100
From: Maciej Wieczor-Retman <maciej.wieczor-retman@...el.com>
To: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
CC: Fenghua Yu <fenghua.yu@...el.com>, Reinette Chatre
	<reinette.chatre@...el.com>, Shuah Khan <shuah@...nel.org>, LKML
	<linux-kernel@...r.kernel.org>, <linux-kselftest@...r.kernel.org>
Subject: Re: [PATCH 2/3] selftests/resctrl: Simplify cleanup in ctrl-c handler

On 2024-02-20 at 15:45:23 +0200, Ilpo Järvinen wrote:
>On Tue, 20 Feb 2024, Maciej Wieczor-Retman wrote:
>
>> Ctrl-c handler isn't aware of what test is currently running. Because of
>> that it executes all cleanups even if they aren't necessary. Since the
>> ctrl-c handler uses the sigaction system no parameters can be passed
>> to it as function arguments.
>> 
>> Add a global variable to make ctrl-c handler aware of the currently run
>> test and only execute the correct cleanup callback.
>> 
>> Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@...el.com>
>> ---
>>  tools/testing/selftests/resctrl/resctrl.h     |  2 ++
>>  .../testing/selftests/resctrl/resctrl_tests.c | 20 +++++++++----------
>>  tools/testing/selftests/resctrl/resctrl_val.c |  2 +-
>>  3 files changed, 13 insertions(+), 11 deletions(-)
>> 
>> diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/selftests/resctrl/resctrl.h
>> index 0f49df4961ea..79b45cbeb628 100644
>> --- a/tools/testing/selftests/resctrl/resctrl.h
>> +++ b/tools/testing/selftests/resctrl/resctrl.h
>> @@ -128,6 +128,8 @@ extern pid_t bm_pid, ppid;
>>  
>>  extern char llc_occup_path[1024];
>>  
>> +extern struct resctrl_test current_test;
>
>Why this is not just a pointer?

I tried making this as a pointer but the 'test' in test_prepare() is of type
'const struct resctrl_test *' and there are warnings about dropping the const
modifier.

>
>> +
>>  int get_vendor(void);
>>  bool check_resctrlfs_support(void);
>>  int filter_dmesg(void);
>> diff --git a/tools/testing/selftests/resctrl/resctrl_tests.c b/tools/testing/selftests/resctrl/resctrl_tests.c
>> index 75fc49ba3efb..b17f7401892c 100644
>> --- a/tools/testing/selftests/resctrl/resctrl_tests.c
>> +++ b/tools/testing/selftests/resctrl/resctrl_tests.c
>> @@ -14,6 +14,12 @@
>>  static volatile int sink_target;
>>  volatile int *value_sink = &sink_target;
>>  
>> +/*
>> + * Set during test preparation for the cleanup function pointer used in
>> + * ctrl-c sa_sigaction
>> + */
>> +struct resctrl_test current_test;
>> +
>>  static struct resctrl_test *resctrl_tests[] = {
>>  	&mbm_test,
>>  	&mba_test,
>> @@ -75,18 +81,12 @@ static void cmd_help(void)
>>  	printf("\t-h: help\n");
>>  }
>>  
>> -void tests_cleanup(void)
>> -{
>> -	mbm_test_cleanup();
>> -	mba_test_cleanup();
>> -	cmt_test_cleanup();
>> -	cat_test_cleanup();
>> -}
>
>This should be removed from resctrl.h too.

Thanks, forgot that it was there too.

>
>> -
>> -static int test_prepare(void)
>> +static int test_prepare(const struct resctrl_test *test)
>>  {
>>  	int res;
>>  
>> +	current_test = *test;
>
>I'd prefer to keep this internal to signal handling functions so that 
>either the struct resctrl_test or just the cleanup handler is passed 
>to signal_handler_register().

Okay, would moving this assignment to signal_handler_register() be okay then?

>
>It'd also allow current_test (or the cleanup function ptr) to be static.
>
>-- 
> i.
>

-- 
Kind regards
Maciej Wieczór-Retman