Prev: drivers/net: Correct NULL test
Next: [PATCH 02/13] net: add a wrapper sk_entry()
From: Arun R Bharadwaj on 9 Feb 2010 03:40
* Arun R Bharadwaj <arun(a)linux.vnet.ibm.com> [2010-02-09 13:58:16]:

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(a)linux.vnet.ibm.com>
---
drivers/cpuidle/cpuidle.c | 93 +++++++++++----------------------------------
drivers/cpuidle/cpuidle.h | 6 --
drivers/cpuidle/driver.c | 7 ---
drivers/cpuidle/governor.c | 13 ++----
drivers/cpuidle/sysfs.c | 34 +++++++++-------
include/linux/cpuidle.h | 6 +-
6 files changed, 56 insertions(+), 103 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)
@@ -47,21 +43,20 @@ 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;
int next_state;
+ ktime_t t1, t2;
+ s64 diff;

/* 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 +70,11 @@ 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()) {
local_irq_enable();
return;
@@ -85,7 +84,18 @@ static void cpuidle_idle_call(void)

/* enter the state and update stats */
dev->last_state = target_state;
- dev->last_residency = target_state->enter(dev, target_state);
+
+ t1 = ktime_get();
+
+ target_state->enter(dev, target_state);
+
+ t2 = ktime_get();
+ diff = ktime_to_us(ktime_sub(t2, t1));
+ if (diff > INT_MAX)
+ diff = INT_MAX;
+
+ dev->last_residency = (int) diff;
+
if (dev->last_state)
target_state = dev->last_state;

@@ -99,35 +109,12 @@ 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);
@@ -137,7 +124,6 @@ EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock
*/
void cpuidle_resume_and_unlock(void)
{
- cpuidle_install_idle_handler();
mutex_unlock(&cpuidle_lock);
}

@@ -185,7 +171,6 @@ int cpuidle_enable_device(struct cpuidle

dev->enabled = 1;

- enabled_devices++;
return 0;

fail_sysfs:
@@ -216,30 +201,16 @@ void cpuidle_disable_device(struct cpuid
cpuidle_curr_governor->disable(dev);

cpuidle_remove_state_sysfs(dev);
- enabled_devices--;
}

EXPORT_SYMBOL_GPL(cpuidle_disable_device);

#ifdef CONFIG_ARCH_HAS_CPU_RELAX
-static int poll_idle(struct cpuidle_device *dev, struct cpuidle_state *st)
+static void poll_idle(struct cpuidle_device *dev, struct cpuidle_state *st)
{
- ktime_t t1, t2;
- s64 diff;
- int ret;
-
- t1 = ktime_get();
local_irq_enable();
while (!need_resched())
cpu_relax();
-
- t2 = ktime_get();
- diff = ktime_to_us(ktime_sub(t2, t1));
- if (diff > INT_MAX)
- diff = INT_MAX;
-
- ret = (int) diff;
- return ret;
}

static void poll_idle_init(struct cpuidle_device *dev)
@@ -269,7 +240,6 @@ 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)
@@ -277,16 +247,9 @@ 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;
@@ -308,7 +271,6 @@ int cpuidle_register_device(struct cpuid
}

cpuidle_enable_device(dev);
- cpuidle_install_idle_handler();

mutex_unlock(&cpuidle_lock);

@@ -324,8 +286,6 @@ 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;

@@ -333,9 +293,6 @@ 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();
@@ -387,8 +344,6 @@ 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
@@ -41,7 +41,7 @@ struct cpuidle_state {
unsigned long long usage;
unsigned long long time; /* in US */

- int (*enter) (struct cpuidle_device *dev,
+ void (*enter) (struct cpuidle_device *dev,
struct cpuidle_state *state);
};

@@ -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
@@ -27,11 +27,8 @@ 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;
+ if (!cpuidle_curr_driver)
+ cpuidle_curr_driver = drv;
spin_unlock(&cpuidle_driver_lock);

return 0;
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo(a)vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
 | 
Pages: 1
Prev: drivers/net: Correct NULL test
Next: [PATCH 02/13] net: add a wrapper sk_entry()