cpufreq: ondemand: Use cpumask_var_t for on-stack cpu mask

[patch] cpufreq: ondemand: Use cpumask_var_t for on-stack cpu mask

Posted by Zhao Liu 3 years, 8 months ago

A cpumask structure on the stack can cause a warning with
CONFIG_NR_CPUS=8192 (e.g. Ubuntu 22.04 uses this):

drivers/cpufreq/cpufreq_ondemand.c: In function 'od_set_powersave_bias':
drivers/cpufreq/cpufreq_ondemand.c:449:1: warning: the frame size of
	1032 bytes is larger than 1024 bytes [-Wframe-larger-than=]
  449 | }
      | ^

CONFIG_CPUMASK_OFFSTACK=y is enabled by default for most distros, and
hence we can work around the warning by using cpumask_var_t.

Signed-off-by: Zhao Liu <zhao1.liu@linux.intel.com>
---
 drivers/cpufreq/cpufreq_ondemand.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index e8fbf970ff07..c52d19d67557 100644
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -416,10 +416,13 @@ static struct dbs_governor od_dbs_gov = {
 static void od_set_powersave_bias(unsigned int powersave_bias)
 {
 	unsigned int cpu;
-	cpumask_t done;
+	cpumask_var_t done;
+
+	if (!alloc_cpumask_var(&done, GFP_KERNEL))
+		return;
 
 	default_powersave_bias = powersave_bias;
-	cpumask_clear(&done);
+	cpumask_clear(done);
 
 	cpus_read_lock();
 	for_each_online_cpu(cpu) {
@@ -428,7 +431,7 @@ static void od_set_powersave_bias(unsigned int powersave_bias)
 		struct dbs_data *dbs_data;
 		struct od_dbs_tuners *od_tuners;
 
-		if (cpumask_test_cpu(cpu, &done))
+		if (cpumask_test_cpu(cpu, done))
 			continue;
 
 		policy = cpufreq_cpu_get_raw(cpu);
@@ -439,13 +442,15 @@ static void od_set_powersave_bias(unsigned int powersave_bias)
 		if (!policy_dbs)
 			continue;
 
-		cpumask_or(&done, &done, policy->cpus);
+		cpumask_or(done, done, policy->cpus);
 
 		dbs_data = policy_dbs->dbs_data;
 		od_tuners = dbs_data->tuners;
 		od_tuners->powersave_bias = default_powersave_bias;
 	}
 	cpus_read_unlock();
+
+	free_cpumask_var(done);
 }
 
 void od_register_powersave_bias_handler(unsigned int (*f)
-- 
2.34.1

Re: [patch] cpufreq: ondemand: Use cpumask_var_t for on-stack cpu mask

Posted by Viresh Kumar 3 years, 8 months ago

On 22-07-22, 10:50, Zhao Liu wrote:
> A cpumask structure on the stack can cause a warning with
> CONFIG_NR_CPUS=8192 (e.g. Ubuntu 22.04 uses this):
> 
> drivers/cpufreq/cpufreq_ondemand.c: In function 'od_set_powersave_bias':
> drivers/cpufreq/cpufreq_ondemand.c:449:1: warning: the frame size of
> 	1032 bytes is larger than 1024 bytes [-Wframe-larger-than=]
>   449 | }
>       | ^
> 
> CONFIG_CPUMASK_OFFSTACK=y is enabled by default for most distros, and
> hence we can work around the warning by using cpumask_var_t.
> 
> Signed-off-by: Zhao Liu <zhao1.liu@linux.intel.com>
> ---
>  drivers/cpufreq/cpufreq_ondemand.c | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
> index e8fbf970ff07..c52d19d67557 100644
> --- a/drivers/cpufreq/cpufreq_ondemand.c
> +++ b/drivers/cpufreq/cpufreq_ondemand.c
> @@ -416,10 +416,13 @@ static struct dbs_governor od_dbs_gov = {
>  static void od_set_powersave_bias(unsigned int powersave_bias)
>  {
>  	unsigned int cpu;
> -	cpumask_t done;
> +	cpumask_var_t done;
> +
> +	if (!alloc_cpumask_var(&done, GFP_KERNEL))
> +		return;
>  
>  	default_powersave_bias = powersave_bias;
> -	cpumask_clear(&done);
> +	cpumask_clear(done);
>  
>  	cpus_read_lock();
>  	for_each_online_cpu(cpu) {
> @@ -428,7 +431,7 @@ static void od_set_powersave_bias(unsigned int powersave_bias)
>  		struct dbs_data *dbs_data;
>  		struct od_dbs_tuners *od_tuners;
>  
> -		if (cpumask_test_cpu(cpu, &done))
> +		if (cpumask_test_cpu(cpu, done))
>  			continue;
>  
>  		policy = cpufreq_cpu_get_raw(cpu);
> @@ -439,13 +442,15 @@ static void od_set_powersave_bias(unsigned int powersave_bias)
>  		if (!policy_dbs)
>  			continue;
>  
> -		cpumask_or(&done, &done, policy->cpus);
> +		cpumask_or(done, done, policy->cpus);
>  
>  		dbs_data = policy_dbs->dbs_data;
>  		od_tuners = dbs_data->tuners;
>  		od_tuners->powersave_bias = default_powersave_bias;
>  	}
>  	cpus_read_unlock();
> +
> +	free_cpumask_var(done);
>  }
>  
>  void od_register_powersave_bias_handler(unsigned int (*f)

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

-- 
viresh

Re: [patch] cpufreq: ondemand: Use cpumask_var_t for on-stack cpu mask

Posted by Rafael J. Wysocki 3 years, 8 months ago

On Mon, Jul 25, 2022 at 12:30 PM Viresh Kumar <viresh.kumar@linaro.org> wrote:
>
> On 22-07-22, 10:50, Zhao Liu wrote:
> > A cpumask structure on the stack can cause a warning with
> > CONFIG_NR_CPUS=8192 (e.g. Ubuntu 22.04 uses this):
> >
> > drivers/cpufreq/cpufreq_ondemand.c: In function 'od_set_powersave_bias':
> > drivers/cpufreq/cpufreq_ondemand.c:449:1: warning: the frame size of
> >       1032 bytes is larger than 1024 bytes [-Wframe-larger-than=]
> >   449 | }
> >       | ^
> >
> > CONFIG_CPUMASK_OFFSTACK=y is enabled by default for most distros, and
> > hence we can work around the warning by using cpumask_var_t.
> >
> > Signed-off-by: Zhao Liu <zhao1.liu@linux.intel.com>
> > ---
> >  drivers/cpufreq/cpufreq_ondemand.c | 13 +++++++++----
> >  1 file changed, 9 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
> > index e8fbf970ff07..c52d19d67557 100644
> > --- a/drivers/cpufreq/cpufreq_ondemand.c
> > +++ b/drivers/cpufreq/cpufreq_ondemand.c
> > @@ -416,10 +416,13 @@ static struct dbs_governor od_dbs_gov = {
> >  static void od_set_powersave_bias(unsigned int powersave_bias)
> >  {
> >       unsigned int cpu;
> > -     cpumask_t done;
> > +     cpumask_var_t done;
> > +
> > +     if (!alloc_cpumask_var(&done, GFP_KERNEL))
> > +             return;
> >
> >       default_powersave_bias = powersave_bias;
> > -     cpumask_clear(&done);
> > +     cpumask_clear(done);
> >
> >       cpus_read_lock();
> >       for_each_online_cpu(cpu) {
> > @@ -428,7 +431,7 @@ static void od_set_powersave_bias(unsigned int powersave_bias)
> >               struct dbs_data *dbs_data;
> >               struct od_dbs_tuners *od_tuners;
> >
> > -             if (cpumask_test_cpu(cpu, &done))
> > +             if (cpumask_test_cpu(cpu, done))
> >                       continue;
> >
> >               policy = cpufreq_cpu_get_raw(cpu);
> > @@ -439,13 +442,15 @@ static void od_set_powersave_bias(unsigned int powersave_bias)
> >               if (!policy_dbs)
> >                       continue;
> >
> > -             cpumask_or(&done, &done, policy->cpus);
> > +             cpumask_or(done, done, policy->cpus);
> >
> >               dbs_data = policy_dbs->dbs_data;
> >               od_tuners = dbs_data->tuners;
> >               od_tuners->powersave_bias = default_powersave_bias;
> >       }
> >       cpus_read_unlock();
> > +
> > +     free_cpumask_var(done);
> >  }
> >
> >  void od_register_powersave_bias_handler(unsigned int (*f)
>
> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

Applied as 5.20 material, thanks!