[PATCH 3/4] PM / Domains: Use power.sybsys_data to reduce overhead

Rafael J. Wysocki
2011-08-08T22:33:07Z

Currently pm_genpd_runtime_resume() has to walk the list of devices
from the device's PM domain to find the corresponding device list
object containing the need_restore field to check if the driver's
.runtime_resume() callback should be executed for the device.
This is suboptimal and can be simplified by using power.sybsys_data
to store device information used by the generic PM domains code.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
arch/arm/mach-shmobile/pm-sh7372.c | 6 --
drivers/base/power/domain.c | 87 ++++++++++++-------------------------
include/linux/pm.h | 9 +++
include/linux/pm_domain.h | 6 --
include/linux/pm_runtime.h | 10 ++++
5 files changed, 51 insertions(+), 67 deletions(-)

Index: linux-2.6/include/linux/pm.h
===================================================================
--- linux-2.6.orig/include/linux/pm.h
+++ linux-2.6/include/linux/pm.h
@@ -422,12 +422,21 @@ enum rpm_request {

struct wakeup_source;

+struct pm_domain_data {
+ struct list_head list_node;
+ struct device *dev;
+ bool need_restore;
+};
+
struct pm_subsys_data {
struct mutex lock;
unsigned int refcount;
#ifdef CONFIG_PM_CLK
struct list_head clock_list;
#endif
+#ifdef CONFIG_PM_GENERIC_DOMAINS
+ struct pm_domain_data domain_data;
+#endif
};

struct dev_pm_info {
Index: linux-2.6/include/linux/pm_domain.h
===================================================================
--- linux-2.6.orig/include/linux/pm_domain.h
+++ linux-2.6/include/linux/pm_domain.h
@@ -61,12 +61,6 @@ struct gpd_link {
struct list_head slave_node;
};

-struct dev_list_entry {
- struct list_head node;
- struct device *dev;
- bool need_restore;
-};
-
#ifdef CONFIG_PM_GENERIC_DOMAINS
extern int pm_genpd_add_device(struct generic_pm_domain *genpd,
struct device *dev);
Index: linux-2.6/drivers/base/power/domain.c
===================================================================
--- linux-2.6.orig/drivers/base/power/domain.c
+++ linux-2.6/drivers/base/power/domain.c
@@ -181,18 +181,18 @@ int pm_genpd_poweron(struct generic_pm_d

/**
* __pm_genpd_save_device - Save the pre-suspend state of a device.
- * @dle: Device list entry of the device to save the state of.
+ * @pdd: Domain data of the device to save the state of.
* @genpd: PM domain the device belongs to.
*/
-static int __pm_genpd_save_device(struct dev_list_entry *dle,
+static int __pm_genpd_save_device(struct pm_domain_data *pdd,
struct generic_pm_domain *genpd)
__releases(&genpd->lock) __acquires(&genpd->lock)
{
- struct device *dev = dle->dev;
+ struct device *dev = pdd->dev;
struct device_driver *drv = dev->driver;
int ret = 0;

- if (dle->need_restore)
+ if (pdd->need_restore)
return 0;

mutex_unlock(&genpd->lock);
@@ -210,24 +210,24 @@ static int __pm_genpd_save_device(struct
mutex_lock(&genpd->lock);

if (!ret)
- dle->need_restore = true;
+ pdd->need_restore = true;

return ret;
}

/**
* __pm_genpd_restore_device - Restore the pre-suspend state of a device.
- * @dle: Device list entry of the device to restore the state of.
+ * @pdd: Domain data of the device to restore the state of.
* @genpd: PM domain the device belongs to.
*/
-static void __pm_genpd_restore_device(struct dev_list_entry *dle,
+static void __pm_genpd_restore_device(struct pm_domain_data *pdd,
struct generic_pm_domain *genpd)
__releases(&genpd->lock) __acquires(&genpd->lock)
{
- struct device *dev = dle->dev;
+ struct device *dev = pdd->dev;
struct device_driver *drv = dev->driver;

- if (!dle->need_restore)
+ if (!pdd->need_restore)
return;

mutex_unlock(&genpd->lock);
@@ -244,7 +244,7 @@ static void __pm_genpd_restore_device(st

mutex_lock(&genpd->lock);

- dle->need_restore = false;
+ pdd->need_restore = false;
}

/**
@@ -286,7 +286,7 @@ void genpd_queue_power_off_work(struct g
static int pm_genpd_poweroff(struct generic_pm_domain *genpd)
__releases(&genpd->lock) __acquires(&genpd->lock)
{
- struct dev_list_entry *dle;
+ struct pm_domain_data *pdd;
struct gpd_link *link;
unsigned int not_suspended;
int ret = 0;
@@ -308,8 +308,8 @@ static int pm_genpd_poweroff(struct gene
return -EBUSY;

not_suspended = 0;
- list_for_each_entry(dle, &genpd->dev_list, node)
- if (dle->dev->driver && !pm_runtime_suspended(dle->dev))
+ list_for_each_entry(pdd, &genpd->dev_list, list_node)
+ if (pdd->dev->driver && !pm_runtime_suspended(pdd->dev))
not_suspended++;

if (not_suspended > genpd->in_progress)
@@ -332,9 +332,9 @@ static int pm_genpd_poweroff(struct gene
genpd->status = GPD_STATE_BUSY;
genpd->poweroff_task = current;

- list_for_each_entry_reverse(dle, &genpd->dev_list, node) {
+ list_for_each_entry_reverse(pdd, &genpd->dev_list, list_node) {
ret = atomic_read(&genpd->sd_count) == 0 ?
- __pm_genpd_save_device(dle, genpd) : -EBUSY;
+ __pm_genpd_save_device(pdd, genpd) : -EBUSY;

if (genpd_abort_poweroff(genpd))
goto out;
@@ -433,24 +433,6 @@ static int pm_genpd_runtime_suspend(stru
}

/**
- * __pm_genpd_runtime_resume - Resume a device belonging to I/O PM domain.
- * @dev: Device to resume.
- * @genpd: PM domain the device belongs to.
- */
-static void __pm_genpd_runtime_resume(struct device *dev,
- struct generic_pm_domain *genpd)
-{
- struct dev_list_entry *dle;
-
- list_for_each_entry(dle, &genpd->dev_list, node) {
- if (dle->dev == dev) {
- __pm_genpd_restore_device(dle, genpd);
- break;
- }
- }
-}
-
-/**
* pm_genpd_runtime_resume - Resume a device belonging to I/O PM domain.
* @dev: Device to resume.
*
@@ -495,7 +477,7 @@ static int pm_genpd_runtime_resume(struc
mutex_lock(&genpd->lock);
}
finish_wait(&genpd->status_wait_queue, &wait);
- __pm_genpd_runtime_resume(dev, genpd);
+ __pm_genpd_restore_device(&dev->power.subsys_data->domain_data, genpd);
genpd->resume_count--;
genpd_set_active(genpd);
wake_up_all(&genpd->status_wait_queue);
@@ -510,8 +492,6 @@ static int pm_genpd_runtime_resume(struc
#else

static inline void genpd_power_off_work_fn(struct work_struct *work) {}
-static inline void __pm_genpd_runtime_resume(struct device *dev,
- struct generic_pm_domain *genpd) {}

#define pm_genpd_runtime_suspend NULL
#define pm_genpd_runtime_resume NULL
@@ -1068,7 +1048,7 @@ static void pm_genpd_complete(struct dev
*/
int pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev)
{
- struct dev_list_entry *dle;
+ struct pm_domain_data *pdd;
int ret = 0;

dev_dbg(dev, "%s()\n", __func__);
@@ -1088,26 +1068,20 @@ int pm_genpd_add_device(struct generic_p
goto out;
}

- list_for_each_entry(dle, &genpd->dev_list, node)
- if (dle->dev == dev) {
+ list_for_each_entry(pdd, &genpd->dev_list, list_node)
+ if (pdd->dev == dev) {
ret = -EINVAL;
goto out;
}

- dle = kzalloc(sizeof(*dle), GFP_KERNEL);
- if (!dle) {
- ret = -ENOMEM;
- goto out;
- }
-
- dle->dev = dev;
- dle->need_restore = false;
- list_add_tail(&dle->node, &genpd->dev_list);
genpd->device_count++;

- spin_lock_irq(&dev->power.lock);
dev->pm_domain = &genpd->domain;
- spin_unlock_irq(&dev->power.lock);
+ dev_pm_get_subsys_data(dev);
+ pdd = &dev->power.subsys_data->domain_data;
+ pdd->dev = dev;
+ pdd->need_restore = false;
+ list_add_tail(&pdd->list_node, &genpd->dev_list);

out:
genpd_release_lock(genpd);
@@ -1123,7 +1097,7 @@ int pm_genpd_add_device(struct generic_p
int pm_genpd_remove_device(struct generic_pm_domain *genpd,
struct device *dev)
{
- struct dev_list_entry *dle;
+ struct pm_domain_data *pdd;
int ret = -EINVAL;

dev_dbg(dev, "%s()\n", __func__);
@@ -1138,17 +1112,16 @@ int pm_genpd_remove_device(struct generi
goto out;
}

- list_for_each_entry(dle, &genpd->dev_list, node) {
- if (dle->dev != dev)
+ list_for_each_entry(pdd, &genpd->dev_list, list_node) {
+ if (pdd->dev != dev)
continue;

- spin_lock_irq(&dev->power.lock);
+ list_del_init(&pdd->list_node);
+ pdd->dev = NULL;
+ dev_pm_put_subsys_data(dev);
dev->pm_domain = NULL;
- spin_unlock_irq(&dev->power.lock);

genpd->device_count--;
- list_del(&dle->node);
- kfree(dle);

ret = 0;
break;
Index: linux-2.6/arch/arm/mach-shmobile/pm-sh7372.c
===================================================================
--- linux-2.6.orig/arch/arm/mach-shmobile/pm-sh7372.c
+++ linux-2.6/arch/arm/mach-shmobile/pm-sh7372.c
@@ -114,11 +114,9 @@ void sh7372_add_device_to_domain(struct
{
struct device *dev = &pdev->dev;

- if (!dev->power.subsys_data) {
- pm_clk_create(dev);
- pm_clk_add(dev, NULL);
- }
pm_genpd_add_device(&sh7372_pd->genpd, dev);
+ if (pm_clk_no_clocks(dev))
+ pm_clk_add(dev, NULL);
}

struct sh7372_pm_domain sh7372_a4lc = {
Index: linux-2.6/include/linux/pm_runtime.h
===================================================================
--- linux-2.6.orig/include/linux/pm_runtime.h
+++ linux-2.6/include/linux/pm_runtime.h
@@ -258,6 +258,12 @@ struct pm_clk_notifier_block {
};

#ifdef CONFIG_PM_CLK
+static inline bool pm_clk_no_clocks(struct device *dev)
+{
+ return dev && dev->power.subsys_data
+ && list_empty(&dev->power.subsys_data->clock_list);
+}
+
extern void pm_clk_init(struct device *dev);
extern int pm_clk_create(struct device *dev);
extern void pm_clk_destroy(struct device *dev);
@@ -266,6 +272,10 @@ extern void pm_clk_remove(struct device
extern int pm_clk_suspend(struct device *dev);
extern int pm_clk_resume(struct device *dev);
#else
+static inline bool pm_clk_no_clocks(struct device *dev)
+{
+ return true;
+}
static inline void pm_clk_init(struct device *dev)
{
}