linux-kernel - Re: [PATCH] locktorture: make verbose writable and control stats print

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Message-ID: <57117D1C.3080109@linaro.org>
Date:	Fri, 15 Apr 2016 16:45:32 -0700
From:	"Shi, Yang" <yang.shi@...aro.org>
To:	paulmck@...ux.vnet.ibm.com
Cc:	linux-kernel@...r.kernel.org, linaro-kernel@...ts.linaro.org
Subject: Re: [PATCH] locktorture: make verbose writable and control stats
 print

On 4/15/2016 4:26 PM, Paul E. McKenney wrote:
> On Fri, Apr 15, 2016 at 01:28:11PM -0700, Yang Shi wrote:
>> When building locktorture test into kernel image, it keeps printing out
>> stats information even though there is no lock type specified.
>>
>> There is already verbose parameter to control print, but it is read-only,
>> so it can't be changed at runtime. Make verbose read-write and control
>> stats print.
>>
>> Signed-off-by: Yang Shi <yang.shi@...aro.org>
>
> Interesting change!
>
> But just out of curiosity, when you boot with locktorture built in,
> do you specify the shutdown_secs boot parameter?  If so, another

No, just use the default value, which is 0 for shutdown_secs.

> approach would be to shutdown immediately upon detecting an error
> during initialization.

In my case, it looks there is not error involved.

>
> If not, I would like to know more about your use case.

In my test, I just built locktorture test into kernel instead of a 
module then check how it behaves, no specific purpose.

It sounds like not a normal approach to use it.

Thanks,
Yang

>
> 							Thanx, Paul
>
>> ---
>>   include/linux/torture.h      |  2 ++
>>   kernel/locking/locktorture.c | 11 +++++++----
>>   2 files changed, 9 insertions(+), 4 deletions(-)
>>
>> diff --git a/include/linux/torture.h b/include/linux/torture.h
>> index 7759fc3..86d6e54 100644
>> --- a/include/linux/torture.h
>> +++ b/include/linux/torture.h
>> @@ -48,6 +48,8 @@
>>   	do { if (verbose) pr_alert("%s" TORTURE_FLAG " %s\n", torture_type, s); } while (0)
>>   #define VERBOSE_TOROUT_ERRSTRING(s) \
>>   	do { if (verbose) pr_alert("%s" TORTURE_FLAG "!!! %s\n", torture_type, s); } while (0)
>> +#define VERBOSE_STRING(s) \
>> +	do { if (verbose) pr_alert("%s", s); } while (0)
>>
>>   /* Definitions for online/offline exerciser. */
>>   int torture_onoff_init(long ooholdoff, long oointerval);
>> diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
>> index 8ef1919..d9838a3 100644
>> --- a/kernel/locking/locktorture.c
>> +++ b/kernel/locking/locktorture.c
>> @@ -55,8 +55,11 @@ torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable.");
>>   torture_param(int, stat_interval, 60,
>>   	     "Number of seconds between stats printk()s");
>>   torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
>> -torture_param(bool, verbose, true,
>> -	     "Enable verbose debugging printk()s");
>> +
>> +static bool verbose = true;
>> +module_param(verbose, bool, 0644);
>> +MODULE_PARM_DESC(verbose,
>> +		 "Enable verbose debugging printk()s");
>>
>>   static char *torture_type = "spin_lock";
>>   module_param(torture_type, charp, 0444);
>> @@ -693,7 +696,7 @@ static void lock_torture_stats_print(void)
>>   	}
>>
>>   	__torture_print_stats(buf, cxt.lwsa, true);
>> -	pr_alert("%s", buf);
>> +	VERBOSE_STRING(buf);
>>   	kfree(buf);
>>
>>   	if (cxt.cur_ops->readlock) {
>> @@ -705,7 +708,7 @@ static void lock_torture_stats_print(void)
>>   		}
>>
>>   		__torture_print_stats(buf, cxt.lrsa, false);
>> -		pr_alert("%s", buf);
>> +		VERBOSE_STRING(buf);
>>   		kfree(buf);
>>   	}
>>   }
>> --
>> 2.0.2
>>
>