Re: [PATCH 8/10] cpumask: convert rcutorture.c

[Paul E. McKenney]

On Sun, Mar 29, 2009 at 12:25:52AM +1030, Rusty Russell wrote:
> 
> We're getting rid of cpumasks on the stack.
> 
> Simply change tmp_mask to a global, and allocate it in
> rcu_torture_init().

Looks good at first glance -- will try running it.

Acked-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>

> Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
> Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
> Cc: Josh Triplett <josh@xxxxxxxxxxxxxxx>
> ---
>  kernel/rcutorture.c |   25 +++++++++++++++++--------
>  1 file changed, 17 insertions(+), 8 deletions(-)
> 
> diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
> --- a/kernel/rcutorture.c
> +++ b/kernel/rcutorture.c
> @@ -126,6 +126,7 @@ static atomic_t n_rcu_torture_error;
>  static atomic_t n_rcu_torture_error;
>  static long n_rcu_torture_timers = 0;
>  static struct list_head rcu_torture_removed;
> +static cpumask_var_t shuffle_tmp_mask;
> 
>  static int stutter_pause_test = 0;
> 
> @@ -889,10 +890,9 @@ static int rcu_idle_cpu;	/* Force all to
>   */
>  static void rcu_torture_shuffle_tasks(void)
>  {
> -	cpumask_t tmp_mask;
>  	int i;
> 
> -	cpus_setall(tmp_mask);
> +	cpumask_setall(shuffle_tmp_mask);
>  	get_online_cpus();
> 
>  	/* No point in shuffling if there is only one online CPU (ex: UP) */
> @@ -902,29 +902,29 @@ static void rcu_torture_shuffle_tasks(vo
>  	}
> 
>  	if (rcu_idle_cpu != -1)
> -		cpu_clear(rcu_idle_cpu, tmp_mask);
> +		cpumask_clear_cpu(rcu_idle_cpu, shuffle_tmp_mask);
> 
> -	set_cpus_allowed_ptr(current, &tmp_mask);
> +	set_cpus_allowed_ptr(current, shuffle_tmp_mask);
> 
>  	if (reader_tasks) {
>  		for (i = 0; i < nrealreaders; i++)
>  			if (reader_tasks[i])
>  				set_cpus_allowed_ptr(reader_tasks[i],
> -						     &tmp_mask);
> +						     shuffle_tmp_mask);
>  	}
> 
>  	if (fakewriter_tasks) {
>  		for (i = 0; i < nfakewriters; i++)
>  			if (fakewriter_tasks[i])
>  				set_cpus_allowed_ptr(fakewriter_tasks[i],
> -						     &tmp_mask);
> +						     shuffle_tmp_mask);
>  	}
> 
>  	if (writer_task)
> -		set_cpus_allowed_ptr(writer_task, &tmp_mask);
> +		set_cpus_allowed_ptr(writer_task, shuffle_tmp_mask);
> 
>  	if (stats_task)
> -		set_cpus_allowed_ptr(stats_task, &tmp_mask);
> +		set_cpus_allowed_ptr(stats_task, shuffle_tmp_mask);
> 
>  	if (rcu_idle_cpu == -1)
>  		rcu_idle_cpu = num_online_cpus() - 1;
> @@ -1012,6 +1012,7 @@ rcu_torture_cleanup(void)
>  	if (shuffler_task) {
>  		VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task");
>  		kthread_stop(shuffler_task);
> +		free_cpumask_var(shuffle_tmp_mask);
>  	}
>  	shuffler_task = NULL;
> 
> @@ -1190,10 +1191,18 @@ rcu_torture_init(void)
>  	}
>  	if (test_no_idle_hz) {
>  		rcu_idle_cpu = num_online_cpus() - 1;
> +
> +		if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
> +			firsterr = -ENOMEM;
> +			VERBOSE_PRINTK_ERRSTRING("Failed to alloc mask");
> +			goto unwind;
> +		}
> +
>  		/* Create the shuffler thread */
>  		shuffler_task = kthread_run(rcu_torture_shuffle, NULL,
>  					  "rcu_torture_shuffle");
>  		if (IS_ERR(shuffler_task)) {
> +			free_cpumask_var(shuffle_tmp_mask);
>  			firsterr = PTR_ERR(shuffler_task);
>  			VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler");
>  			shuffler_task = NULL;
> 
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