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Subject[v5 RFC PATCH 1/7]: cpuidle: cleanup drivers/cpuidle/cpuidle.c
* Arun R Bharadwaj <arun@linux.vnet.ibm.com> [2009-09-22 11:03:14]:

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 | 59 ++++++---------------------------------------
drivers/cpuidle/cpuidle.h | 1
drivers/cpuidle/governor.c | 3 --
include/linux/cpuidle.h | 3 ++
4 files changed, 11 insertions(+), 55 deletions(-)
Index: linux.trees.git/drivers/cpuidle/cpuidle.c
===================================================================
--- linux.trees.git.orig/drivers/cpuidle/cpuidle.c
+++ linux.trees.git/drivers/cpuidle/cpuidle.c
@@ -24,20 +24,6 @@ DEFINE_PER_CPU(struct cpuidle_device *,

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)
-{
- cpu_idle_wait();
-}
-#elif defined(CONFIG_SMP)
-# error "Arch needs cpu_idle_wait() equivalent here"
-#else /* !CONFIG_ARCH_HAS_CPU_IDLE_WAIT && !CONFIG_SMP */
-static void cpuidle_kick_cpus(void) {}
-#endif

static int __cpuidle_register_device(struct cpuidle_device *dev);

@@ -46,7 +32,7 @@ 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;
@@ -54,13 +40,10 @@ 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;
}
@@ -74,7 +57,11 @@ 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];
@@ -94,35 +81,11 @@ 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();
}

EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock);
@@ -132,7 +95,6 @@ EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock
*/
void cpuidle_resume_and_unlock(void)
{
- cpuidle_install_idle_handler();
mutex_unlock(&cpuidle_lock);
}

@@ -180,7 +142,6 @@ int cpuidle_enable_device(struct cpuidle

dev->enabled = 1;

- enabled_devices++;
return 0;

fail_sysfs:
@@ -211,7 +172,6 @@ void cpuidle_disable_device(struct cpuid
cpuidle_curr_governor->disable(dev);

cpuidle_remove_state_sysfs(dev);
- enabled_devices--;
}

EXPORT_SYMBOL_GPL(cpuidle_disable_device);
@@ -303,7 +263,6 @@ int cpuidle_register_device(struct cpuid
}

cpuidle_enable_device(dev);
- cpuidle_install_idle_handler();

mutex_unlock(&cpuidle_lock);

@@ -382,8 +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
@@ -48,8 +48,6 @@ int cpuidle_switch_governor(struct cpuid
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);
@@ -63,7 +61,6 @@ int cpuidle_switch_governor(struct cpuid
return -EINVAL;
list_for_each_entry(dev, &cpuidle_detected_devices, device_list)
cpuidle_enable_device(dev);
- cpuidle_install_idle_handler();
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
@@ -112,6 +112,9 @@ static inline int cpuidle_get_last_resid
return dev->last_residency;
}

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

/****************************
* 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
@@ -9,7 +9,6 @@

/* 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;

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