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

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Message-ID: <20160415232613.GC3687@linux.vnet.ibm.com>
Date:	Fri, 15 Apr 2016 16:26:13 -0700
From:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To:	Yang Shi <yang.shi@...aro.org>
Cc:	linux-kernel@...r.kernel.org, linaro-kernel@...ts.linaro.org
Subject: Re: [PATCH] locktorture: make verbose writable and control stats
 print

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

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

							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
>