[v9 PATCH 2/9]: cpuidle: cleanup drivers/cpuidle/cpuidle.c

Arun R Bharadwaj
2009-10-16T09:41:13Z

This patch cleans up drivers/cpuidle/cpuidle.c
Earlier cpuidle assumed pm_idle as the default idle loop. Break that
assumption and make it more generic. cpuidle_idle_call() which is the
main idle loop of cpuidle is to be called by architectures which have
registered to cpuidle.

Remove routines cpuidle_install/uninstall_idle_handler() and
cpuidle_kick_cpus() which are not needed anymore.

Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com>
---
drivers/cpuidle/cpuidle.c | 63 ++++++---------------------------------------
drivers/cpuidle/cpuidle.h | 6 +---
drivers/cpuidle/driver.c | 4 --
drivers/cpuidle/governor.c | 13 +++------
drivers/cpuidle/sysfs.c | 34 +++++++++++++-----------
include/linux/cpuidle.h | 4 ++
6 files changed, 38 insertions(+), 86 deletions(-)

Index: linux.trees.git/drivers/cpuidle/cpuidle.c
===================================================================
--- linux.trees.git.orig/drivers/cpuidle/cpuidle.c
+++ linux.trees.git/drivers/cpuidle/cpuidle.c
@@ -24,10 +24,6 @@
DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices);

DEFINE_MUTEX(cpuidle_lock);
-LIST_HEAD(cpuidle_detected_devices);
-static void (*pm_idle_old)(void);
-
-static int enabled_devices;

#if defined(CONFIG_ARCH_HAS_CPU_IDLE_WAIT)
static void cpuidle_kick_cpus(void)
@@ -47,7 +43,7 @@ static int __cpuidle_register_device(str
*
* NOTE: no locks or semaphores should be used here
*/
-static void cpuidle_idle_call(void)
+void cpuidle_idle_call(void)
{
struct cpuidle_device *dev = __get_cpu_var(cpuidle_devices);
struct cpuidle_state *target_state;
@@ -55,13 +51,10 @@ static void cpuidle_idle_call(void)

/* check if the device is ready */
if (!dev || !dev->enabled) {
- if (pm_idle_old)
- pm_idle_old();
- else
#if defined(CONFIG_ARCH_HAS_DEFAULT_IDLE)
- default_idle();
+ default_idle();
#else
- local_irq_enable();
+ local_irq_enable();
#endif
return;
}
@@ -75,7 +68,11 @@ static void cpuidle_idle_call(void)
hrtimer_peek_ahead_timers();
#endif
/* ask the governor for the next state */
- next_state = cpuidle_curr_governor->select(dev);
+ if (dev->state_count > 1)
+ next_state = cpuidle_curr_governor->select(dev);
+ else
+ next_state = 0;
+
if (need_resched())
return;
target_state = &dev->states[next_state];
@@ -96,35 +93,12 @@ static void cpuidle_idle_call(void)
}

/**
- * cpuidle_install_idle_handler - installs the cpuidle idle loop handler
- */
-void cpuidle_install_idle_handler(void)
-{
- if (enabled_devices && (pm_idle != cpuidle_idle_call)) {
- /* Make sure all changes finished before we switch to new idle */
- smp_wmb();
- pm_idle = cpuidle_idle_call;
- }
-}
-
-/**
- * cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler
- */
-void cpuidle_uninstall_idle_handler(void)
-{
- if (enabled_devices && pm_idle_old && (pm_idle != pm_idle_old)) {
- pm_idle = pm_idle_old;
- cpuidle_kick_cpus();
- }
-}
-
-/**
* cpuidle_pause_and_lock - temporarily disables CPUIDLE
*/
void cpuidle_pause_and_lock(void)
{
mutex_lock(&cpuidle_lock);
- cpuidle_uninstall_idle_handler();
+ cpuidle_kick_cpus();
}

EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock);
@@ -134,7 +108,6 @@ EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock
*/
void cpuidle_resume_and_unlock(void)
{
- cpuidle_install_idle_handler();
mutex_unlock(&cpuidle_lock);
}

@@ -182,7 +155,6 @@ int cpuidle_enable_device(struct cpuidle

dev->enabled = 1;

- enabled_devices++;
return 0;

fail_sysfs:
@@ -213,7 +185,6 @@ void cpuidle_disable_device(struct cpuid
cpuidle_curr_governor->disable(dev);

cpuidle_remove_state_sysfs(dev);
- enabled_devices--;
}

EXPORT_SYMBOL_GPL(cpuidle_disable_device);
@@ -266,7 +237,6 @@ static void poll_idle_init(struct cpuidl
*/
static int __cpuidle_register_device(struct cpuidle_device *dev)
{
- int ret;
struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu);

if (!sys_dev)
@@ -274,16 +244,9 @@ static int __cpuidle_register_device(str
if (!try_module_get(cpuidle_curr_driver->owner))
return -EINVAL;

- init_completion(&dev->kobj_unregister);
-
poll_idle_init(dev);

per_cpu(cpuidle_devices, dev->cpu) = dev;
- list_add(&dev->device_list, &cpuidle_detected_devices);
- if ((ret = cpuidle_add_sysfs(sys_dev))) {
- module_put(cpuidle_curr_driver->owner);
- return ret;
- }

dev->registered = 1;
return 0;
@@ -305,7 +268,6 @@ int cpuidle_register_device(struct cpuid
}

cpuidle_enable_device(dev);
- cpuidle_install_idle_handler();

mutex_unlock(&cpuidle_lock);

@@ -321,8 +283,6 @@ EXPORT_SYMBOL_GPL(cpuidle_register_devic
*/
void cpuidle_unregister_device(struct cpuidle_device *dev)
{
- struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu);
-
if (dev->registered == 0)
return;

@@ -330,9 +290,6 @@ void cpuidle_unregister_device(struct cp

cpuidle_disable_device(dev);

- cpuidle_remove_sysfs(sys_dev);
- list_del(&dev->device_list);
- wait_for_completion(&dev->kobj_unregister);
per_cpu(cpuidle_devices, dev->cpu) = NULL;

cpuidle_resume_and_unlock();
@@ -384,8 +341,6 @@ static int __init cpuidle_init(void)
{
int ret;

- pm_idle_old = pm_idle;
-
ret = cpuidle_add_class_sysfs(&cpu_sysdev_class);
if (ret)
return ret;
Index: linux.trees.git/drivers/cpuidle/governor.c
===================================================================
--- linux.trees.git.orig/drivers/cpuidle/governor.c
+++ linux.trees.git/drivers/cpuidle/governor.c
@@ -43,16 +43,14 @@ static struct cpuidle_governor * __cpuid
*/
int cpuidle_switch_governor(struct cpuidle_governor *gov)
{
- struct cpuidle_device *dev;
+ int cpu;

if (gov == cpuidle_curr_governor)
return 0;

- cpuidle_uninstall_idle_handler();
-
if (cpuidle_curr_governor) {
- list_for_each_entry(dev, &cpuidle_detected_devices, device_list)
- cpuidle_disable_device(dev);
+ for_each_online_cpu(cpu)
+ cpuidle_disable_device(per_cpu(cpuidle_devices, cpu));
module_put(cpuidle_curr_governor->owner);
}

@@ -61,9 +59,8 @@ int cpuidle_switch_governor(struct cpuid
if (gov) {
if (!try_module_get(cpuidle_curr_governor->owner))
return -EINVAL;
- list_for_each_entry(dev, &cpuidle_detected_devices, device_list)
- cpuidle_enable_device(dev);
- cpuidle_install_idle_handler();
+ for_each_online_cpu(cpu)
+ cpuidle_enable_device(per_cpu(cpuidle_devices, cpu));
printk(KERN_INFO "cpuidle: using governor %s\n", gov->name);
}

Index: linux.trees.git/include/linux/cpuidle.h
===================================================================
--- linux.trees.git.orig/include/linux/cpuidle.h
+++ linux.trees.git/include/linux/cpuidle.h
@@ -92,7 +92,6 @@ struct cpuidle_device {
struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
struct cpuidle_state *last_state;

- struct list_head device_list;
struct kobject kobj;
struct completion kobj_unregister;
void *governor_data;
@@ -112,6 +111,9 @@ static inline int cpuidle_get_last_resid
return dev->last_residency;
}

+extern struct cpuidle_driver *cpuidle_curr_driver;
+extern void cpuidle_idle_call(void);
+

/****************************
* CPUIDLE DRIVER INTERFACE *
Index: linux.trees.git/drivers/cpuidle/cpuidle.h
===================================================================
--- linux.trees.git.orig/drivers/cpuidle/cpuidle.h
+++ linux.trees.git/drivers/cpuidle/cpuidle.h
@@ -9,9 +9,7 @@

/* For internal use only */
extern struct cpuidle_governor *cpuidle_curr_governor;
-extern struct cpuidle_driver *cpuidle_curr_driver;
extern struct list_head cpuidle_governors;
-extern struct list_head cpuidle_detected_devices;
extern struct mutex cpuidle_lock;
extern spinlock_t cpuidle_driver_lock;

@@ -27,7 +25,7 @@ extern int cpuidle_add_class_sysfs(struc
extern void cpuidle_remove_class_sysfs(struct sysdev_class *cls);
extern int cpuidle_add_state_sysfs(struct cpuidle_device *device);
extern void cpuidle_remove_state_sysfs(struct cpuidle_device *device);
-extern int cpuidle_add_sysfs(struct sys_device *sysdev);
-extern void cpuidle_remove_sysfs(struct sys_device *sysdev);
+extern int cpuidle_add_sysfs(struct cpuidle_device *device);
+extern void cpuidle_remove_sysfs(struct cpuidle_device *device);

#endif /* __DRIVER_CPUIDLE_H */
Index: linux.trees.git/drivers/cpuidle/sysfs.c
===================================================================
--- linux.trees.git.orig/drivers/cpuidle/sysfs.c
+++ linux.trees.git/drivers/cpuidle/sysfs.c
@@ -311,6 +311,13 @@ int cpuidle_add_state_sysfs(struct cpuid
int i, ret = -ENOMEM;
struct cpuidle_state_kobj *kobj;

+ init_completion(&device->kobj_unregister);
+
+ ret = cpuidle_add_sysfs(device);
+ if (ret) {
+ module_put(cpuidle_curr_driver->owner);
+ return ret;
+ }
/* state statistics */
for (i = 0; i < device->state_count; i++) {
kobj = kzalloc(sizeof(struct cpuidle_state_kobj), GFP_KERNEL);
@@ -347,35 +354,32 @@ void cpuidle_remove_state_sysfs(struct c

for (i = 0; i < device->state_count; i++)
cpuidle_free_state_kobj(device, i);
+
+ cpuidle_remove_sysfs(device);
}

/**
* cpuidle_add_sysfs - creates a sysfs instance for the target device
- * @sysdev: the target device
+ * @device: the target device
*/
-int cpuidle_add_sysfs(struct sys_device *sysdev)
+int cpuidle_add_sysfs(struct cpuidle_device *device)
{
- int cpu = sysdev->id;
- struct cpuidle_device *dev;
int error;
+ struct sys_device *sysdev = get_cpu_sysdev((unsigned long)device->cpu);

- dev = per_cpu(cpuidle_devices, cpu);
- error = kobject_init_and_add(&dev->kobj, &ktype_cpuidle, &sysdev->kobj,
- "cpuidle");
+ error = kobject_init_and_add(&device->kobj, &ktype_cpuidle,
+ &sysdev->kobj, "cpuidle");
if (!error)
- kobject_uevent(&dev->kobj, KOBJ_ADD);
+ kobject_uevent(&device->kobj, KOBJ_ADD);
return error;
}

/**
* cpuidle_remove_sysfs - deletes a sysfs instance on the target device
- * @sysdev: the target device
+ * @device: the target device
*/
-void cpuidle_remove_sysfs(struct sys_device *sysdev)
+void cpuidle_remove_sysfs(struct cpuidle_device *device)
{
- int cpu = sysdev->id;
- struct cpuidle_device *dev;
-
- dev = per_cpu(cpuidle_devices, cpu);
- kobject_put(&dev->kobj);
+ kobject_put(&device->kobj);
+ wait_for_completion(&device->kobj_unregister);
}
Index: linux.trees.git/drivers/cpuidle/driver.c
===================================================================
--- linux.trees.git.orig/drivers/cpuidle/driver.c
+++ linux.trees.git/drivers/cpuidle/driver.c
@@ -27,10 +27,6 @@ int cpuidle_register_driver(struct cpuid
return -EINVAL;

spin_lock(&cpuidle_driver_lock);
- if (cpuidle_curr_driver) {
- spin_unlock(&cpuidle_driver_lock);
- return -EBUSY;
- }
cpuidle_curr_driver = drv;
spin_unlock(&cpuidle_driver_lock);