diff mbox series

[3/4] PM / Domains: Search for the CPU device outside the genpd lock

Message ID 20190425090413.10700-4-ulf.hansson@linaro.org (mailing list archive)
State Mainlined, archived
Commit b24e196586fecafed1c3cff9b2f87c1a64138ade
Headers show
Series PM / Domains: Improve support for CPUs in genpd | expand

Commit Message

Ulf Hansson April 25, 2019, 9:04 a.m. UTC
While attaching/detaching a device to a PM domain (genpd) that has the
GENPD_FLAG_CPU_DOMAIN set, genpd iterates the cpu_possible_mask to check
whether the device corresponds to a CPU. This iteration is done while
holding the genpd's lock, which is unnecessary. Let's avoid the locking,
by restructuring the corresponding code a bit.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/base/power/domain.c | 52 +++++++++++++++++++------------------
 1 file changed, 27 insertions(+), 25 deletions(-)

Comments

Viresh Kumar April 25, 2019, 9:45 a.m. UTC | #1
On 25-04-19, 11:04, Ulf Hansson wrote:
> While attaching/detaching a device to a PM domain (genpd) that has the
> GENPD_FLAG_CPU_DOMAIN set, genpd iterates the cpu_possible_mask to check
> whether the device corresponds to a CPU. This iteration is done while
> holding the genpd's lock, which is unnecessary. Let's avoid the locking,
> by restructuring the corresponding code a bit.
> 
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> ---
>  drivers/base/power/domain.c | 52 +++++++++++++++++++------------------
>  1 file changed, 27 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 93298b7db408..da1c99178943 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -1450,8 +1450,8 @@ static void genpd_free_dev_data(struct device *dev,
>  	dev_pm_put_subsys_data(dev);
>  }
>  
> -static void __genpd_update_cpumask(struct generic_pm_domain *genpd,
> -				   int cpu, bool set, unsigned int depth)
> +static void genpd_update_cpumask(struct generic_pm_domain *genpd,
> +				 int cpu, bool set, unsigned int depth)
>  {
>  	struct gpd_link *link;
>  
> @@ -1462,7 +1462,7 @@ static void __genpd_update_cpumask(struct generic_pm_domain *genpd,
>  		struct generic_pm_domain *master = link->master;
>  
>  		genpd_lock_nested(master, depth + 1);
> -		__genpd_update_cpumask(master, cpu, set, depth + 1);
> +		genpd_update_cpumask(master, cpu, set, depth + 1);
>  		genpd_unlock(master);
>  	}
>  
> @@ -1472,38 +1472,37 @@ static void __genpd_update_cpumask(struct generic_pm_domain *genpd,
>  		cpumask_clear_cpu(cpu, genpd->cpus);
>  }
>  
> -static void genpd_update_cpumask(struct generic_pm_domain *genpd,
> -				 struct device *dev, bool set)
> +static void genpd_set_cpumask(struct generic_pm_domain *genpd, int cpu)
> +{
> +	if (cpu >= 0)
> +		genpd_update_cpumask(genpd, cpu, true, 0);
> +}
> +
> +static void genpd_clear_cpumask(struct generic_pm_domain *genpd, int cpu)
> +{
> +	if (cpu >= 0)
> +		genpd_update_cpumask(genpd, cpu, false, 0);
> +}
> +
> +static int genpd_get_cpu(struct generic_pm_domain *genpd, struct device *dev)
>  {
>  	int cpu;
>  
>  	if (!genpd_is_cpu_domain(genpd))
> -		return;
> +		return -1;
>  
>  	for_each_possible_cpu(cpu) {
> -		if (get_cpu_device(cpu) == dev) {
> -			__genpd_update_cpumask(genpd, cpu, set, 0);
> -			return;
> -		}
> +		if (get_cpu_device(cpu) == dev)
> +			return cpu;
>  	}
> -}
>  
> -static void genpd_set_cpumask(struct generic_pm_domain *genpd,
> -			      struct device *dev)
> -{
> -	genpd_update_cpumask(genpd, dev, true);
> -}
> -
> -static void genpd_clear_cpumask(struct generic_pm_domain *genpd,
> -				struct device *dev)
> -{
> -	genpd_update_cpumask(genpd, dev, false);
> +	return -1;
>  }
>  
>  static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev)
>  {
>  	struct generic_pm_domain_data *gpd_data;
> -	int ret;
> +	int ret, cpu;
>  
>  	dev_dbg(dev, "%s()\n", __func__);
>  
> @@ -1514,13 +1513,15 @@ static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev)
>  	if (IS_ERR(gpd_data))
>  		return PTR_ERR(gpd_data);
>  
> +	cpu = genpd_get_cpu(genpd, dev);
> +
>  	ret = genpd->attach_dev ? genpd->attach_dev(genpd, dev) : 0;
>  	if (ret)
>  		goto out;
>  
>  	genpd_lock(genpd);
>  
> -	genpd_set_cpumask(genpd, dev);
> +	genpd_set_cpumask(genpd, cpu);

Should we check if "cpu" is valid here ? As that was done earlier.

>  	dev_pm_domain_set(dev, &genpd->domain);
>  
>  	genpd->device_count++;
> @@ -1560,13 +1561,14 @@ static int genpd_remove_device(struct generic_pm_domain *genpd,
>  {
>  	struct generic_pm_domain_data *gpd_data;
>  	struct pm_domain_data *pdd;
> -	int ret = 0;
> +	int cpu, ret = 0;
>  
>  	dev_dbg(dev, "%s()\n", __func__);
>  
>  	pdd = dev->power.subsys_data->domain_data;
>  	gpd_data = to_gpd_data(pdd);
>  	dev_pm_qos_remove_notifier(dev, &gpd_data->nb);
> +	cpu = genpd_get_cpu(genpd, dev);
>  
>  	genpd_lock(genpd);
>  
> @@ -1578,7 +1580,7 @@ static int genpd_remove_device(struct generic_pm_domain *genpd,
>  	genpd->device_count--;
>  	genpd->max_off_time_changed = true;
>  
> -	genpd_clear_cpumask(genpd, dev);
> +	genpd_clear_cpumask(genpd, cpu);

Same here.

>  	dev_pm_domain_set(dev, NULL);
>  
>  	list_del_init(&pdd->list_node);
> -- 
> 2.17.1
Ulf Hansson April 25, 2019, 10:14 a.m. UTC | #2
On Thu, 25 Apr 2019 at 11:45, Viresh Kumar <viresh.kumar@linaro.org> wrote:
>
> On 25-04-19, 11:04, Ulf Hansson wrote:
> > While attaching/detaching a device to a PM domain (genpd) that has the
> > GENPD_FLAG_CPU_DOMAIN set, genpd iterates the cpu_possible_mask to check
> > whether the device corresponds to a CPU. This iteration is done while
> > holding the genpd's lock, which is unnecessary. Let's avoid the locking,
> > by restructuring the corresponding code a bit.
> >
> > Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> > ---
> >  drivers/base/power/domain.c | 52 +++++++++++++++++++------------------
> >  1 file changed, 27 insertions(+), 25 deletions(-)
> >
> > diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> > index 93298b7db408..da1c99178943 100644
> > --- a/drivers/base/power/domain.c
> > +++ b/drivers/base/power/domain.c
> > @@ -1450,8 +1450,8 @@ static void genpd_free_dev_data(struct device *dev,
> >       dev_pm_put_subsys_data(dev);
> >  }
> >
> > -static void __genpd_update_cpumask(struct generic_pm_domain *genpd,
> > -                                int cpu, bool set, unsigned int depth)
> > +static void genpd_update_cpumask(struct generic_pm_domain *genpd,
> > +                              int cpu, bool set, unsigned int depth)
> >  {
> >       struct gpd_link *link;
> >
> > @@ -1462,7 +1462,7 @@ static void __genpd_update_cpumask(struct generic_pm_domain *genpd,
> >               struct generic_pm_domain *master = link->master;
> >
> >               genpd_lock_nested(master, depth + 1);
> > -             __genpd_update_cpumask(master, cpu, set, depth + 1);
> > +             genpd_update_cpumask(master, cpu, set, depth + 1);
> >               genpd_unlock(master);
> >       }
> >
> > @@ -1472,38 +1472,37 @@ static void __genpd_update_cpumask(struct generic_pm_domain *genpd,
> >               cpumask_clear_cpu(cpu, genpd->cpus);
> >  }
> >
> > -static void genpd_update_cpumask(struct generic_pm_domain *genpd,
> > -                              struct device *dev, bool set)
> > +static void genpd_set_cpumask(struct generic_pm_domain *genpd, int cpu)
> > +{
> > +     if (cpu >= 0)
> > +             genpd_update_cpumask(genpd, cpu, true, 0);
> > +}
> > +
> > +static void genpd_clear_cpumask(struct generic_pm_domain *genpd, int cpu)
> > +{
> > +     if (cpu >= 0)
> > +             genpd_update_cpumask(genpd, cpu, false, 0);
> > +}
> > +
> > +static int genpd_get_cpu(struct generic_pm_domain *genpd, struct device *dev)
> >  {
> >       int cpu;
> >
> >       if (!genpd_is_cpu_domain(genpd))
> > -             return;
> > +             return -1;
> >
> >       for_each_possible_cpu(cpu) {
> > -             if (get_cpu_device(cpu) == dev) {
> > -                     __genpd_update_cpumask(genpd, cpu, set, 0);
> > -                     return;
> > -             }
> > +             if (get_cpu_device(cpu) == dev)
> > +                     return cpu;
> >       }
> > -}
> >
> > -static void genpd_set_cpumask(struct generic_pm_domain *genpd,
> > -                           struct device *dev)
> > -{
> > -     genpd_update_cpumask(genpd, dev, true);
> > -}
> > -
> > -static void genpd_clear_cpumask(struct generic_pm_domain *genpd,
> > -                             struct device *dev)
> > -{
> > -     genpd_update_cpumask(genpd, dev, false);
> > +     return -1;
> >  }
> >
> >  static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev)
> >  {
> >       struct generic_pm_domain_data *gpd_data;
> > -     int ret;
> > +     int ret, cpu;
> >
> >       dev_dbg(dev, "%s()\n", __func__);
> >
> > @@ -1514,13 +1513,15 @@ static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev)
> >       if (IS_ERR(gpd_data))
> >               return PTR_ERR(gpd_data);
> >
> > +     cpu = genpd_get_cpu(genpd, dev);
> > +
> >       ret = genpd->attach_dev ? genpd->attach_dev(genpd, dev) : 0;
> >       if (ret)
> >               goto out;
> >
> >       genpd_lock(genpd);
> >
> > -     genpd_set_cpumask(genpd, dev);
> > +     genpd_set_cpumask(genpd, cpu);
>
> Should we check if "cpu" is valid here ? As that was done earlier.

This is being done in the new version of genpd_set|clear_cpumask(). Like below.

"if (cpu >= 0)"...

>
> >       dev_pm_domain_set(dev, &genpd->domain);
> >
> >       genpd->device_count++;
> > @@ -1560,13 +1561,14 @@ static int genpd_remove_device(struct generic_pm_domain *genpd,
> >  {
> >       struct generic_pm_domain_data *gpd_data;
> >       struct pm_domain_data *pdd;
> > -     int ret = 0;
> > +     int cpu, ret = 0;
> >
> >       dev_dbg(dev, "%s()\n", __func__);
> >
> >       pdd = dev->power.subsys_data->domain_data;
> >       gpd_data = to_gpd_data(pdd);
> >       dev_pm_qos_remove_notifier(dev, &gpd_data->nb);
> > +     cpu = genpd_get_cpu(genpd, dev);
> >
> >       genpd_lock(genpd);
> >
> > @@ -1578,7 +1580,7 @@ static int genpd_remove_device(struct generic_pm_domain *genpd,
> >       genpd->device_count--;
> >       genpd->max_off_time_changed = true;
> >
> > -     genpd_clear_cpumask(genpd, dev);
> > +     genpd_clear_cpumask(genpd, cpu);
>
> Same here.

See above.

>
> >       dev_pm_domain_set(dev, NULL);
> >
> >       list_del_init(&pdd->list_node);
> > --
> > 2.17.1
>
> --
> viresh

Thanks for reviewing!

Kind regards
Uffe
Viresh Kumar April 25, 2019, 10:17 a.m. UTC | #3
On 25-04-19, 11:04, Ulf Hansson wrote:
> While attaching/detaching a device to a PM domain (genpd) that has the
> GENPD_FLAG_CPU_DOMAIN set, genpd iterates the cpu_possible_mask to check
> whether the device corresponds to a CPU. This iteration is done while
> holding the genpd's lock, which is unnecessary. Let's avoid the locking,
> by restructuring the corresponding code a bit.
> 
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> ---
>  drivers/base/power/domain.c | 52 +++++++++++++++++++------------------
>  1 file changed, 27 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 93298b7db408..da1c99178943 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -1450,8 +1450,8 @@ static void genpd_free_dev_data(struct device *dev,
>  	dev_pm_put_subsys_data(dev);
>  }
>  
> -static void __genpd_update_cpumask(struct generic_pm_domain *genpd,
> -				   int cpu, bool set, unsigned int depth)
> +static void genpd_update_cpumask(struct generic_pm_domain *genpd,
> +				 int cpu, bool set, unsigned int depth)
>  {
>  	struct gpd_link *link;
>  
> @@ -1462,7 +1462,7 @@ static void __genpd_update_cpumask(struct generic_pm_domain *genpd,
>  		struct generic_pm_domain *master = link->master;
>  
>  		genpd_lock_nested(master, depth + 1);
> -		__genpd_update_cpumask(master, cpu, set, depth + 1);
> +		genpd_update_cpumask(master, cpu, set, depth + 1);
>  		genpd_unlock(master);
>  	}
>  
> @@ -1472,38 +1472,37 @@ static void __genpd_update_cpumask(struct generic_pm_domain *genpd,
>  		cpumask_clear_cpu(cpu, genpd->cpus);
>  }
>  
> -static void genpd_update_cpumask(struct generic_pm_domain *genpd,
> -				 struct device *dev, bool set)
> +static void genpd_set_cpumask(struct generic_pm_domain *genpd, int cpu)
> +{
> +	if (cpu >= 0)
> +		genpd_update_cpumask(genpd, cpu, true, 0);
> +}
> +
> +static void genpd_clear_cpumask(struct generic_pm_domain *genpd, int cpu)
> +{
> +	if (cpu >= 0)
> +		genpd_update_cpumask(genpd, cpu, false, 0);
> +}
> +
> +static int genpd_get_cpu(struct generic_pm_domain *genpd, struct device *dev)
>  {
>  	int cpu;
>  
>  	if (!genpd_is_cpu_domain(genpd))
> -		return;
> +		return -1;
>  
>  	for_each_possible_cpu(cpu) {
> -		if (get_cpu_device(cpu) == dev) {
> -			__genpd_update_cpumask(genpd, cpu, set, 0);
> -			return;
> -		}
> +		if (get_cpu_device(cpu) == dev)
> +			return cpu;
>  	}
> -}
>  
> -static void genpd_set_cpumask(struct generic_pm_domain *genpd,
> -			      struct device *dev)
> -{
> -	genpd_update_cpumask(genpd, dev, true);
> -}
> -
> -static void genpd_clear_cpumask(struct generic_pm_domain *genpd,
> -				struct device *dev)
> -{
> -	genpd_update_cpumask(genpd, dev, false);
> +	return -1;
>  }
>  
>  static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev)
>  {
>  	struct generic_pm_domain_data *gpd_data;
> -	int ret;
> +	int ret, cpu;
>  
>  	dev_dbg(dev, "%s()\n", __func__);
>  
> @@ -1514,13 +1513,15 @@ static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev)
>  	if (IS_ERR(gpd_data))
>  		return PTR_ERR(gpd_data);
>  
> +	cpu = genpd_get_cpu(genpd, dev);
> +
>  	ret = genpd->attach_dev ? genpd->attach_dev(genpd, dev) : 0;
>  	if (ret)
>  		goto out;
>  
>  	genpd_lock(genpd);
>  
> -	genpd_set_cpumask(genpd, dev);
> +	genpd_set_cpumask(genpd, cpu);
>  	dev_pm_domain_set(dev, &genpd->domain);
>  
>  	genpd->device_count++;
> @@ -1560,13 +1561,14 @@ static int genpd_remove_device(struct generic_pm_domain *genpd,
>  {
>  	struct generic_pm_domain_data *gpd_data;
>  	struct pm_domain_data *pdd;
> -	int ret = 0;
> +	int cpu, ret = 0;
>  
>  	dev_dbg(dev, "%s()\n", __func__);
>  
>  	pdd = dev->power.subsys_data->domain_data;
>  	gpd_data = to_gpd_data(pdd);
>  	dev_pm_qos_remove_notifier(dev, &gpd_data->nb);
> +	cpu = genpd_get_cpu(genpd, dev);
>  
>  	genpd_lock(genpd);
>  
> @@ -1578,7 +1580,7 @@ static int genpd_remove_device(struct generic_pm_domain *genpd,
>  	genpd->device_count--;
>  	genpd->max_off_time_changed = true;
>  
> -	genpd_clear_cpumask(genpd, dev);
> +	genpd_clear_cpumask(genpd, cpu);
>  	dev_pm_domain_set(dev, NULL);
>  
>  	list_del_init(&pdd->list_node);

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

Patch

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 93298b7db408..da1c99178943 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -1450,8 +1450,8 @@  static void genpd_free_dev_data(struct device *dev,
 	dev_pm_put_subsys_data(dev);
 }
 
-static void __genpd_update_cpumask(struct generic_pm_domain *genpd,
-				   int cpu, bool set, unsigned int depth)
+static void genpd_update_cpumask(struct generic_pm_domain *genpd,
+				 int cpu, bool set, unsigned int depth)
 {
 	struct gpd_link *link;
 
@@ -1462,7 +1462,7 @@  static void __genpd_update_cpumask(struct generic_pm_domain *genpd,
 		struct generic_pm_domain *master = link->master;
 
 		genpd_lock_nested(master, depth + 1);
-		__genpd_update_cpumask(master, cpu, set, depth + 1);
+		genpd_update_cpumask(master, cpu, set, depth + 1);
 		genpd_unlock(master);
 	}
 
@@ -1472,38 +1472,37 @@  static void __genpd_update_cpumask(struct generic_pm_domain *genpd,
 		cpumask_clear_cpu(cpu, genpd->cpus);
 }
 
-static void genpd_update_cpumask(struct generic_pm_domain *genpd,
-				 struct device *dev, bool set)
+static void genpd_set_cpumask(struct generic_pm_domain *genpd, int cpu)
+{
+	if (cpu >= 0)
+		genpd_update_cpumask(genpd, cpu, true, 0);
+}
+
+static void genpd_clear_cpumask(struct generic_pm_domain *genpd, int cpu)
+{
+	if (cpu >= 0)
+		genpd_update_cpumask(genpd, cpu, false, 0);
+}
+
+static int genpd_get_cpu(struct generic_pm_domain *genpd, struct device *dev)
 {
 	int cpu;
 
 	if (!genpd_is_cpu_domain(genpd))
-		return;
+		return -1;
 
 	for_each_possible_cpu(cpu) {
-		if (get_cpu_device(cpu) == dev) {
-			__genpd_update_cpumask(genpd, cpu, set, 0);
-			return;
-		}
+		if (get_cpu_device(cpu) == dev)
+			return cpu;
 	}
-}
 
-static void genpd_set_cpumask(struct generic_pm_domain *genpd,
-			      struct device *dev)
-{
-	genpd_update_cpumask(genpd, dev, true);
-}
-
-static void genpd_clear_cpumask(struct generic_pm_domain *genpd,
-				struct device *dev)
-{
-	genpd_update_cpumask(genpd, dev, false);
+	return -1;
 }
 
 static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev)
 {
 	struct generic_pm_domain_data *gpd_data;
-	int ret;
+	int ret, cpu;
 
 	dev_dbg(dev, "%s()\n", __func__);
 
@@ -1514,13 +1513,15 @@  static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev)
 	if (IS_ERR(gpd_data))
 		return PTR_ERR(gpd_data);
 
+	cpu = genpd_get_cpu(genpd, dev);
+
 	ret = genpd->attach_dev ? genpd->attach_dev(genpd, dev) : 0;
 	if (ret)
 		goto out;
 
 	genpd_lock(genpd);
 
-	genpd_set_cpumask(genpd, dev);
+	genpd_set_cpumask(genpd, cpu);
 	dev_pm_domain_set(dev, &genpd->domain);
 
 	genpd->device_count++;
@@ -1560,13 +1561,14 @@  static int genpd_remove_device(struct generic_pm_domain *genpd,
 {
 	struct generic_pm_domain_data *gpd_data;
 	struct pm_domain_data *pdd;
-	int ret = 0;
+	int cpu, ret = 0;
 
 	dev_dbg(dev, "%s()\n", __func__);
 
 	pdd = dev->power.subsys_data->domain_data;
 	gpd_data = to_gpd_data(pdd);
 	dev_pm_qos_remove_notifier(dev, &gpd_data->nb);
+	cpu = genpd_get_cpu(genpd, dev);
 
 	genpd_lock(genpd);
 
@@ -1578,7 +1580,7 @@  static int genpd_remove_device(struct generic_pm_domain *genpd,
 	genpd->device_count--;
 	genpd->max_off_time_changed = true;
 
-	genpd_clear_cpumask(genpd, dev);
+	genpd_clear_cpumask(genpd, cpu);
 	dev_pm_domain_set(dev, NULL);
 
 	list_del_init(&pdd->list_node);