[v7 PATCH 0/7]: cpuidle/x86/POWER: Cleanup idle power management code in x86, cleanup drivers/cpuidle/cpuidle.c and introduce cpuidle to POWER.

[v7 PATCH 0/7]: cpuidle/x86/POWER: Cleanup idle power management code in x86, cleanup drivers/cpuidle/cpuidle.c and introduce cpuidle to POWER.

[Arun R Bharadwaj]

Hi

Please consider this for inclusion into the testing tree.

This patchset introduces cpuidle infrastructure to POWER, prototyping
for pSeries, and also does a major refactoring of current x86 idle
power management and a cleanup of cpuidle infrastructure.

Earlier discussions on the same can be found at:

v6 --> http://lkml.org/lkml/2009/9/22/180
v5 --> http://lkml.org/lkml/2009/9/22/26
v4 --> http://lkml.org/lkml/2009/9/1/133
v3 --> http://lkml.org/lkml/2009/8/27/124
v2 --> http://lkml.org/lkml/2009/8/26/233
v1 --> http://lkml.org/lkml/2009/8/19/150


Changes in this version:
-----------------------------------------

* Earlier implementation maintained a list of cpuidle devices and
  the list was traversed to disable and enable the cpuidle devices
  when switching governors. This list is not necessary and is removed.
  Now, we get the per cpu structure cpuidle_devices and disable and
  enable it for each online cpu while switching governors.

* Earlier iterations were buggy w.r.t the sysfs interface of the cpuidle.
  This iteration removes the bug in PATCH 1/7.

* In PATCH 7/7, smt_snooze_delay was not being updated whenever it was
  changed through the sysfs interface. Provide a helper routine to
  update it.

* In PATCH 7/7, the idle loops are renamed to denote the idle states
  to avoid any confusion.


thanks,
arun

[v7 PATCH 1/7]: cpuidle: cleanup drivers/cpuidle/cpuidle.c

[Arun R Bharadwaj]

* Arun R Bharadwaj <arun@linux.vnet.ibm.com> [2009-10-06 20:54:21]:

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  |   62 +++++----------------------------------------
 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, 37 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 +93,11 @@ 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);
@@ -134,7 +107,6 @@ EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock
  */
 void cpuidle_resume_and_unlock(void)
 {
-	cpuidle_install_idle_handler();
 	mutex_unlock(&cpuidle_lock);
 }
 
@@ -182,7 +154,6 @@ int cpuidle_enable_device(struct cpuidle
 
 	dev->enabled = 1;
 
-	enabled_devices++;
 	return 0;
 
 fail_sysfs:
@@ -213,7 +184,6 @@ 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 +236,6 @@ 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 +243,9 @@ 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 +267,6 @@ int cpuidle_register_device(struct cpuid
 	}
 
 	cpuidle_enable_device(dev);
-	cpuidle_install_idle_handler();
 
 	mutex_unlock(&cpuidle_lock);
 
@@ -321,8 +282,6 @@ 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 +289,6 @@ 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 +340,6 @@ 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 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
@@ -9,9 +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);
 

[v7 PATCH 2/7]: cpuidle: implement a list based approach to register a set of idle routines.

[Arun R Bharadwaj]

* Arun R Bharadwaj <arun@linux.vnet.ibm.com> [2009-10-06 20:54:21]:

Implement a list based registering mechanism for architectures which
have multiple sets of idle routines which are to be registered.

Currently, in x86 it is done by merely setting pm_idle = idle_routine
and managing this pm_idle pointer is messy.

To give an example of how this mechanism works:
In x86, initially, idle routine is selected from the set of poll/mwait/
c1e/default idle loops. So the selected idle loop is registered in cpuidle
as one idle state cpuidle devices. Once ACPI comes up, it registers
another set of idle states on top of this state. Again, suppose a module
registers another set of idle loops, it is added to this list.

This provides a clean way of registering and unregistering idle state
routines.

In the current implementation, pm_idle is set as the current idle routine
being used and the old idle routine has to be maintained and when a module
registers/unregisters an idle routine, confusion arises.


Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com>
---
 drivers/cpuidle/cpuidle.c |   54 ++++++++++++++++++++++++++++++++++++++++------
 include/linux/cpuidle.h   |    1 
 2 files changed, 48 insertions(+), 7 deletions(-)

Index: linux.trees.git/drivers/cpuidle/cpuidle.c
===================================================================
--- linux.trees.git.orig/drivers/cpuidle/cpuidle.c
+++ linux.trees.git/drivers/cpuidle/cpuidle.c
@@ -22,6 +22,7 @@
 #include "cpuidle.h"
 
 DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
+DEFINE_PER_CPU(struct list_head, cpuidle_devices_list);
 
 DEFINE_MUTEX(cpuidle_lock);
 
@@ -112,6 +113,45 @@ void cpuidle_resume_and_unlock(void)
 
 EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock);
 
+int cpuidle_add_to_list(struct cpuidle_device *dev)
+{
+	int ret, cpu = dev->cpu;
+	struct cpuidle_device *old_dev;
+
+	if (!list_empty(&per_cpu(cpuidle_devices_list, cpu))) {
+		old_dev = list_first_entry(&per_cpu(cpuidle_devices_list, cpu),
+				struct cpuidle_device, idle_list);
+		cpuidle_remove_state_sysfs(old_dev);
+	}
+
+	list_add(&dev->idle_list, &per_cpu(cpuidle_devices_list, cpu));
+	ret = cpuidle_add_state_sysfs(dev);
+	return ret;
+}
+
+void cpuidle_remove_from_list(struct cpuidle_device *dev)
+{
+	struct cpuidle_device *temp_dev;
+	struct list_head *pos;
+	int ret, cpu = dev->cpu;
+
+	list_for_each(pos, &per_cpu(cpuidle_devices_list, cpu)) {
+		temp_dev = container_of(pos, struct cpuidle_device, idle_list);
+		if (dev == temp_dev) {
+			list_del(&temp_dev->idle_list);
+			cpuidle_remove_state_sysfs(temp_dev);
+			break;
+		}
+	}
+
+	if (!list_empty(&per_cpu(cpuidle_devices_list, cpu))) {
+		temp_dev = list_first_entry(&per_cpu(cpuidle_devices_list, cpu),
+					struct cpuidle_device, idle_list);
+		ret = cpuidle_add_state_sysfs(temp_dev);
+	}
+	cpuidle_kick_cpus();
+}
+
 /**
  * cpuidle_enable_device - enables idle PM for a CPU
  * @dev: the CPU
@@ -136,9 +176,6 @@ int cpuidle_enable_device(struct cpuidle
 			return ret;
 	}
 
-	if ((ret = cpuidle_add_state_sysfs(dev)))
-		return ret;
-
 	if (cpuidle_curr_governor->enable &&
 	    (ret = cpuidle_curr_governor->enable(dev)))
 		goto fail_sysfs;
@@ -157,7 +194,7 @@ int cpuidle_enable_device(struct cpuidle
 	return 0;
 
 fail_sysfs:
-	cpuidle_remove_state_sysfs(dev);
+	cpuidle_remove_from_list(dev);
 
 	return ret;
 }
@@ -182,8 +219,6 @@ void cpuidle_disable_device(struct cpuid
 
 	if (cpuidle_curr_governor->disable)
 		cpuidle_curr_governor->disable(dev);
-
-	cpuidle_remove_state_sysfs(dev);
 }
 
 EXPORT_SYMBOL_GPL(cpuidle_disable_device);
@@ -267,6 +302,7 @@ int cpuidle_register_device(struct cpuid
 	}
 
 	cpuidle_enable_device(dev);
+	cpuidle_add_to_list(dev);
 
 	mutex_unlock(&cpuidle_lock);
 
@@ -288,6 +324,7 @@ void cpuidle_unregister_device(struct cp
 	cpuidle_pause_and_lock();
 
 	cpuidle_disable_device(dev);
+	cpuidle_remove_from_list(dev);
 
 	per_cpu(cpuidle_devices, dev->cpu) = NULL;
 
@@ -338,12 +375,15 @@ static inline void latency_notifier_init
  */
 static int __init cpuidle_init(void)
 {
-	int ret;
+	int ret, cpu;
 
 	ret = cpuidle_add_class_sysfs(&cpu_sysdev_class);
 	if (ret)
 		return ret;
 
+	for_each_possible_cpu(cpu)
+		INIT_LIST_HEAD(&per_cpu(cpuidle_devices_list, cpu));
+
 	latency_notifier_init(&cpuidle_latency_notifier);
 
 	return 0;
Index: linux.trees.git/include/linux/cpuidle.h
===================================================================
--- linux.trees.git.orig/include/linux/cpuidle.h
+++ linux.trees.git/include/linux/cpuidle.h
@@ -92,6 +92,7 @@ struct cpuidle_device {
 	struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
 	struct cpuidle_state	*last_state;
 
+	struct list_head	idle_list;
 	struct kobject		kobj;
 	struct completion	kobj_unregister;
 	void			*governor_data;

[v7 PATCH 3/7]: x86: refactor x86 idle power management code and remove all instances of pm_idle.

[Arun R Bharadwaj]

* Arun R Bharadwaj <arun@linux.vnet.ibm.com> [2009-10-06 20:54:21]:

This patch cleans up x86 of all instances of pm_idle.

pm_idle which was earlier called from cpu_idle() idle loop
is replaced by cpuidle_idle_call.

x86 also registers to cpuidle when the idle routine is selected,
by populating the cpuidle_device data structure for each cpu.

This is replicated for apm module and for xen, which also used pm_idle.


Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com>
---
 arch/x86/kernel/apm_32.c     |   37 ++++++++++++++++++--
 arch/x86/kernel/process.c    |   79 ++++++++++++++++++++++++++++++++-----------
 arch/x86/kernel/process_32.c |    3 +
 arch/x86/kernel/process_64.c |    3 +
 arch/x86/xen/setup.c         |   22 +++++++++++
 5 files changed, 118 insertions(+), 26 deletions(-)

Index: linux.trees.git/arch/x86/kernel/process.c
===================================================================
--- linux.trees.git.orig/arch/x86/kernel/process.c
+++ linux.trees.git/arch/x86/kernel/process.c
@@ -9,6 +9,7 @@
 #include <linux/pm.h>
 #include <linux/clockchips.h>
 #include <linux/random.h>
+#include <linux/cpuidle.h>
 #include <trace/events/power.h>
 #include <asm/system.h>
 #include <asm/apic.h>
@@ -244,12 +245,6 @@ int sys_vfork(struct pt_regs *regs)
 unsigned long boot_option_idle_override = 0;
 EXPORT_SYMBOL(boot_option_idle_override);
 
-/*
- * Powermanagement idle function, if any..
- */
-void (*pm_idle)(void);
-EXPORT_SYMBOL(pm_idle);
-
 #ifdef CONFIG_X86_32
 /*
  * This halt magic was a workaround for ancient floppy DMA
@@ -329,17 +324,15 @@ static void do_nothing(void *unused)
 }
 
 /*
- * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
- * pm_idle and update to new pm_idle value. Required while changing pm_idle
- * handler on SMP systems.
+ * cpu_idle_wait - Required while changing idle routine handler on SMP systems.
  *
- * Caller must have changed pm_idle to the new value before the call. Old
- * pm_idle value will not be used by any CPU after the return of this function.
+ * Caller must have changed idle routine to the new value before the call. Old
+ * value will not be used by any CPU after the return of this function.
  */
 void cpu_idle_wait(void)
 {
 	smp_mb();
-	/* kick all the CPUs so that they exit out of pm_idle */
+	/* kick all the CPUs so that they exit out of idle loop */
 	smp_call_function(do_nothing, NULL, 1);
 }
 EXPORT_SYMBOL_GPL(cpu_idle_wait);
@@ -518,15 +511,59 @@ static void c1e_idle(void)
 		default_idle();
 }
 
+static void (*local_idle)(void);
+DEFINE_PER_CPU(struct cpuidle_device, idle_devices);
+
+struct cpuidle_driver cpuidle_default_driver = {
+	.name =         "cpuidle_default",
+};
+
+static int local_idle_loop(struct cpuidle_device *dev, struct cpuidle_state *st)
+{
+	ktime_t t1, t2;
+	s64 diff;
+	int ret;
+
+	t1 = ktime_get();
+	local_idle();
+	t2 = ktime_get();
+
+	diff = ktime_to_us(ktime_sub(t2, t1));
+	if (diff > INT_MAX)
+		diff = INT_MAX;
+	ret = (int) diff;
+
+	return ret;
+}
+
+static int setup_cpuidle_simple(void)
+{
+	struct cpuidle_device *dev;
+	int cpu;
+
+	if (!cpuidle_curr_driver)
+		cpuidle_register_driver(&cpuidle_default_driver);
+
+	for_each_online_cpu(cpu) {
+		dev = &per_cpu(idle_devices, cpu);
+		dev->cpu = cpu;
+		dev->states[0].enter = local_idle_loop;
+		dev->state_count = 1;
+		cpuidle_register_device(dev);
+	}
+	return 0;
+}
+device_initcall(setup_cpuidle_simple);
+
 void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
 {
 #ifdef CONFIG_SMP
-	if (pm_idle == poll_idle && smp_num_siblings > 1) {
+	if (local_idle == poll_idle && smp_num_siblings > 1) {
 		printk(KERN_WARNING "WARNING: polling idle and HT enabled,"
 			" performance may degrade.\n");
 	}
 #endif
-	if (pm_idle)
+	if (local_idle)
 		return;
 
 	if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) {
@@ -534,18 +571,20 @@ void __cpuinit select_idle_routine(const
 		 * One CPU supports mwait => All CPUs supports mwait
 		 */
 		printk(KERN_INFO "using mwait in idle threads.\n");
-		pm_idle = mwait_idle;
+		local_idle = mwait_idle;
 	} else if (check_c1e_idle(c)) {
 		printk(KERN_INFO "using C1E aware idle routine\n");
-		pm_idle = c1e_idle;
+		local_idle = c1e_idle;
 	} else
-		pm_idle = default_idle;
+		local_idle = default_idle;
+
+	return;
 }
 
 void __init init_c1e_mask(void)
 {
 	/* If we're using c1e_idle, we need to allocate c1e_mask. */
-	if (pm_idle == c1e_idle)
+	if (local_idle == c1e_idle)
 		zalloc_cpumask_var(&c1e_mask, GFP_KERNEL);
 }
 
@@ -556,7 +595,7 @@ static int __init idle_setup(char *str)
 
 	if (!strcmp(str, "poll")) {
 		printk("using polling idle threads.\n");
-		pm_idle = poll_idle;
+		local_idle = poll_idle;
 	} else if (!strcmp(str, "mwait"))
 		force_mwait = 1;
 	else if (!strcmp(str, "halt")) {
@@ -567,7 +606,7 @@ static int __init idle_setup(char *str)
 		 * To continue to load the CPU idle driver, don't touch
 		 * the boot_option_idle_override.
 		 */
-		pm_idle = default_idle;
+		local_idle = default_idle;
 		idle_halt = 1;
 		return 0;
 	} else if (!strcmp(str, "nomwait")) {
Index: linux.trees.git/arch/x86/kernel/process_32.c
===================================================================
--- linux.trees.git.orig/arch/x86/kernel/process_32.c
+++ linux.trees.git/arch/x86/kernel/process_32.c
@@ -40,6 +40,7 @@
 #include <linux/uaccess.h>
 #include <linux/io.h>
 #include <linux/kdebug.h>
+#include <linux/cpuidle.h>
 
 #include <asm/pgtable.h>
 #include <asm/system.h>
@@ -113,7 +114,7 @@ void cpu_idle(void)
 			local_irq_disable();
 			/* Don't trace irqs off for idle */
 			stop_critical_timings();
-			pm_idle();
+			cpuidle_idle_call();
 			start_critical_timings();
 		}
 		tick_nohz_restart_sched_tick();
Index: linux.trees.git/arch/x86/kernel/process_64.c
===================================================================
--- linux.trees.git.orig/arch/x86/kernel/process_64.c
+++ linux.trees.git/arch/x86/kernel/process_64.c
@@ -39,6 +39,7 @@
 #include <linux/io.h>
 #include <linux/ftrace.h>
 #include <linux/dmi.h>
+#include <linux/cpuidle.h>
 
 #include <asm/pgtable.h>
 #include <asm/system.h>
@@ -142,7 +143,7 @@ void cpu_idle(void)
 			enter_idle();
 			/* Don't trace irqs off for idle */
 			stop_critical_timings();
-			pm_idle();
+			cpuidle_idle_call();
 			start_critical_timings();
 			/* In many cases the interrupt that ended idle
 			   has already called exit_idle. But some idle
Index: linux.trees.git/arch/x86/kernel/apm_32.c
===================================================================
--- linux.trees.git.orig/arch/x86/kernel/apm_32.c
+++ linux.trees.git/arch/x86/kernel/apm_32.c
@@ -2257,6 +2257,38 @@ static struct dmi_system_id __initdata a
 	{ }
 };
 
+DEFINE_PER_CPU(struct cpuidle_device, apm_idle_devices);
+
+struct cpuidle_driver cpuidle_apm_driver = {
+	.name =         "cpuidle_apm",
+};
+
+void __cpuinit setup_cpuidle_apm(void)
+{
+	struct cpuidle_device *dev;
+
+	if (!cpuidle_curr_driver)
+		cpuidle_register_driver(&cpuidle_apm_driver);
+
+	dev = &per_cpu(apm_idle_devices, smp_processor_id());
+	dev->cpu = smp_processor_id();
+	dev->states[0].enter = apm_cpu_idle;
+	dev->state_count = 1;
+	cpuidle_register_device(dev);
+}
+
+void exit_cpuidle_apm(void)
+{
+	struct cpuidle_device *dev;
+	int cpu;
+
+	for_each_online_cpu(cpu) {
+		dev = &per_cpu(apm_idle_devices, cpu);
+		cpuidle_unregister_device(dev);
+	}
+}
+
+
 /*
  * Just start the APM thread. We do NOT want to do APM BIOS
  * calls from anything but the APM thread, if for no other reason
@@ -2394,8 +2426,7 @@ static int __init apm_init(void)
 	if (HZ != 100)
 		idle_period = (idle_period * HZ) / 100;
 	if (idle_threshold < 100) {
-		original_pm_idle = pm_idle;
-		pm_idle  = apm_cpu_idle;
+		setup_cpuidle_apm();
 		set_pm_idle = 1;
 	}
 
@@ -2407,7 +2438,7 @@ static void __exit apm_exit(void)
 	int error;
 
 	if (set_pm_idle) {
-		pm_idle = original_pm_idle;
+		exit_cpuidle_apm();
 		/*
 		 * We are about to unload the current idle thread pm callback
 		 * (pm_idle), Wait for all processors to update cached/local
Index: linux.trees.git/arch/x86/xen/setup.c
===================================================================
--- linux.trees.git.orig/arch/x86/xen/setup.c
+++ linux.trees.git/arch/x86/xen/setup.c
@@ -8,6 +8,7 @@
 #include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/pm.h>
+#include <linux/cpuidle.h>
 
 #include <asm/elf.h>
 #include <asm/vdso.h>
@@ -151,6 +152,25 @@ void __cpuinit xen_enable_syscall(void)
 #endif /* CONFIG_X86_64 */
 }
 
+DEFINE_PER_CPU(struct cpuidle_device, xen_idle_devices);
+struct cpuidle_driver cpuidle_xen_driver = {
+	.name =         "cpuidle_xen",
+};
+
+void __cpuinit setup_cpuidle_xen(void)
+{
+	struct cpuidle_device *dev;
+
+	if (!cpuidle_curr_driver)
+		cpuidle_register_driver(&cpuidle_xen_driver);
+
+	dev = &per_cpu(xen_idle_devices, smp_processor_id());
+	dev->cpu = smp_processor_id();
+	dev->states[0].enter = xen_idle;
+	dev->state_count = 1;
+	cpuidle_register_device(dev);
+}
+
 void __init xen_arch_setup(void)
 {
 	struct physdev_set_iopl set_iopl;
@@ -186,7 +206,7 @@ void __init xen_arch_setup(void)
 	       MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ?
 	       COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);
 
-	pm_idle = xen_idle;
+	setup_cpuidle_xen();
 
 	paravirt_disable_iospace();
 

Re: [v7 PATCH 3/7]: x86: refactor x86 idle power management code and remove all instances of pm_idle.

[Peter Zijlstra]

On Tue, 2009-10-06 at 21:01 +0530, Arun R Bharadwaj wrote:
> +++ linux.trees.git/arch/x86/kernel/process.c
> @@ -9,6 +9,7 @@
>  #include <linux/pm.h>
>  #include <linux/clockchips.h>
>  #include <linux/random.h>
> +#include <linux/cpuidle.h>
>  #include <trace/events/power.h>
>  #include <asm/system.h>
>  #include <asm/apic.h>
> @@ -244,12 +245,6 @@ int sys_vfork(struct pt_regs *regs)
>  unsigned long boot_option_idle_override = 0;
>  EXPORT_SYMBOL(boot_option_idle_override);
>  
> -/*
> - * Powermanagement idle function, if any..
> - */
> -void (*pm_idle)(void);
> -EXPORT_SYMBOL(pm_idle);
> -
>  #ifdef CONFIG_X86_32
>  /*
>   * This halt magic was a workaround for ancient floppy DMA
> @@ -329,17 +324,15 @@ static void do_nothing(void *unused)
>  }
>  
>  /*
> - * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
> - * pm_idle and update to new pm_idle value. Required while changing pm_idle
> - * handler on SMP systems.
> + * cpu_idle_wait - Required while changing idle routine handler on SMP systems.
>   *
> - * Caller must have changed pm_idle to the new value before the call. Old
> - * pm_idle value will not be used by any CPU after the return of this function.
> + * Caller must have changed idle routine to the new value before the call. Old
> + * value will not be used by any CPU after the return of this function.
>   */
>  void cpu_idle_wait(void)
>  {
>         smp_mb();
> -       /* kick all the CPUs so that they exit out of pm_idle */
> +       /* kick all the CPUs so that they exit out of idle loop */
>         smp_call_function(do_nothing, NULL, 1);
>  }
>  EXPORT_SYMBOL_GPL(cpu_idle_wait);
> @@ -518,15 +511,59 @@ static void c1e_idle(void)
>                 default_idle();
>  }
>  
> +static void (*local_idle)(void);
> +DEFINE_PER_CPU(struct cpuidle_device, idle_devices);
> +
> +struct cpuidle_driver cpuidle_default_driver = {
> +       .name =         "cpuidle_default",
> +};
> +
> +static int local_idle_loop(struct cpuidle_device *dev, struct cpuidle_state *st)
> +{
> +       ktime_t t1, t2;
> +       s64 diff;
> +       int ret;
> +
> +       t1 = ktime_get();
> +       local_idle();
> +       t2 = ktime_get();
> +
> +       diff = ktime_to_us(ktime_sub(t2, t1));
> +       if (diff > INT_MAX)
> +               diff = INT_MAX;
> +       ret = (int) diff;
> +
> +       return ret;
> +}
> +
> +static int setup_cpuidle_simple(void)
> +{
> +       struct cpuidle_device *dev;
> +       int cpu;
> +
> +       if (!cpuidle_curr_driver)
> +               cpuidle_register_driver(&cpuidle_default_driver);
> +
> +       for_each_online_cpu(cpu) {
> +               dev = &per_cpu(idle_devices, cpu);
> +               dev->cpu = cpu;
> +               dev->states[0].enter = local_idle_loop;
> +               dev->state_count = 1;
> +               cpuidle_register_device(dev);
> +       }
> +       return 0;
> +}
> +device_initcall(setup_cpuidle_simple);
> +
>  void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
>  {
>  #ifdef CONFIG_SMP
> -       if (pm_idle == poll_idle && smp_num_siblings > 1) {
> +       if (local_idle == poll_idle && smp_num_siblings > 1) {
>                 printk(KERN_WARNING "WARNING: polling idle and HT enabled,"
>                         " performance may degrade.\n");
>         }
>  #endif
> -       if (pm_idle)
> +       if (local_idle)
>                 return;
>  
>         if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) {
> @@ -534,18 +571,20 @@ void __cpuinit select_idle_routine(const
>                  * One CPU supports mwait => All CPUs supports mwait
>                  */
>                 printk(KERN_INFO "using mwait in idle threads.\n");
> -               pm_idle = mwait_idle;
> +               local_idle = mwait_idle;
>         } else if (check_c1e_idle(c)) {
>                 printk(KERN_INFO "using C1E aware idle routine\n");
> -               pm_idle = c1e_idle;
> +               local_idle = c1e_idle;
>         } else
> -               pm_idle = default_idle;
> +               local_idle = default_idle;
> +
> +       return;
>  }
>  
>  void __init init_c1e_mask(void)
>  {
>         /* If we're using c1e_idle, we need to allocate c1e_mask. */
> -       if (pm_idle == c1e_idle)
> +       if (local_idle == c1e_idle)
>                 zalloc_cpumask_var(&c1e_mask, GFP_KERNEL);
>  }
>  
> @@ -556,7 +595,7 @@ static int __init idle_setup(char *str)
>  
>         if (!strcmp(str, "poll")) {
>                 printk("using polling idle threads.\n");
> -               pm_idle = poll_idle;
> +               local_idle = poll_idle;
>         } else if (!strcmp(str, "mwait"))
>                 force_mwait = 1;
>         else if (!strcmp(str, "halt")) {
> @@ -567,7 +606,7 @@ static int __init idle_setup(char *str)
>                  * To continue to load the CPU idle driver, don't touch
>                  * the boot_option_idle_override.
>                  */
> -               pm_idle = default_idle;
> +               local_idle = default_idle;
>                 idle_halt = 1;
>                 return 0;
>         } else if (!strcmp(str, "nomwait")) {


What guarantees that the cpuidle bits actually select this
cpuidle_default driver when you do idle=poll?

Also, cpuidle already has a poll loop in it, why duplicate that?

Re: [v7 PATCH 3/7]: x86: refactor x86 idle power management code and remove all instances of pm_idle.

[Arun R Bharadwaj]

* Peter Zijlstra <a.p.zijlstra@chello.nl> [2009-10-07 16:45:50]:

> On Tue, 2009-10-06 at 21:01 +0530, Arun R Bharadwaj wrote:
> > +++ linux.trees.git/arch/x86/kernel/process.c
> > @@ -9,6 +9,7 @@
> >  #include <linux/pm.h>
> >  #include <linux/clockchips.h>
> >  #include <linux/random.h>
> > +#include <linux/cpuidle.h>
> >  #include <trace/events/power.h>
> >  #include <asm/system.h>
> >  #include <asm/apic.h>
> > @@ -244,12 +245,6 @@ int sys_vfork(struct pt_regs *regs)
> >  unsigned long boot_option_idle_override = 0;
> >  EXPORT_SYMBOL(boot_option_idle_override);
> >  
> > -/*
> > - * Powermanagement idle function, if any..
> > - */
> > -void (*pm_idle)(void);
> > -EXPORT_SYMBOL(pm_idle);
> > -
> >  #ifdef CONFIG_X86_32
> >  /*
> >   * This halt magic was a workaround for ancient floppy DMA
> > @@ -329,17 +324,15 @@ static void do_nothing(void *unused)
> >  }
> >  
> >  /*
> > - * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
> > - * pm_idle and update to new pm_idle value. Required while changing pm_idle
> > - * handler on SMP systems.
> > + * cpu_idle_wait - Required while changing idle routine handler on SMP systems.
> >   *
> > - * Caller must have changed pm_idle to the new value before the call. Old
> > - * pm_idle value will not be used by any CPU after the return of this function.
> > + * Caller must have changed idle routine to the new value before the call. Old
> > + * value will not be used by any CPU after the return of this function.
> >   */
> >  void cpu_idle_wait(void)
> >  {
> >         smp_mb();
> > -       /* kick all the CPUs so that they exit out of pm_idle */
> > +       /* kick all the CPUs so that they exit out of idle loop */
> >         smp_call_function(do_nothing, NULL, 1);
> >  }
> >  EXPORT_SYMBOL_GPL(cpu_idle_wait);
> > @@ -518,15 +511,59 @@ static void c1e_idle(void)
> >                 default_idle();
> >  }
> >  
> > +static void (*local_idle)(void);
> > +DEFINE_PER_CPU(struct cpuidle_device, idle_devices);
> > +
> > +struct cpuidle_driver cpuidle_default_driver = {
> > +       .name =         "cpuidle_default",
> > +};
> > +
> > +static int local_idle_loop(struct cpuidle_device *dev, struct cpuidle_state *st)
> > +{
> > +       ktime_t t1, t2;
> > +       s64 diff;
> > +       int ret;
> > +
> > +       t1 = ktime_get();
> > +       local_idle();
> > +       t2 = ktime_get();
> > +
> > +       diff = ktime_to_us(ktime_sub(t2, t1));
> > +       if (diff > INT_MAX)
> > +               diff = INT_MAX;
> > +       ret = (int) diff;
> > +
> > +       return ret;
> > +}
> > +
> > +static int setup_cpuidle_simple(void)
> > +{
> > +       struct cpuidle_device *dev;
> > +       int cpu;
> > +
> > +       if (!cpuidle_curr_driver)
> > +               cpuidle_register_driver(&cpuidle_default_driver);
> > +
> > +       for_each_online_cpu(cpu) {
> > +               dev = &per_cpu(idle_devices, cpu);
> > +               dev->cpu = cpu;
> > +               dev->states[0].enter = local_idle_loop;
> > +               dev->state_count = 1;
> > +               cpuidle_register_device(dev);
> > +       }
> > +       return 0;
> > +}
> > +device_initcall(setup_cpuidle_simple);
> > +
> >  void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
> >  {
> >  #ifdef CONFIG_SMP
> > -       if (pm_idle == poll_idle && smp_num_siblings > 1) {
> > +       if (local_idle == poll_idle && smp_num_siblings > 1) {
> >                 printk(KERN_WARNING "WARNING: polling idle and HT enabled,"
> >                         " performance may degrade.\n");
> >         }
> >  #endif
> > -       if (pm_idle)
> > +       if (local_idle)
> >                 return;
> >  
> >         if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) {
> > @@ -534,18 +571,20 @@ void __cpuinit select_idle_routine(const
> >                  * One CPU supports mwait => All CPUs supports mwait
> >                  */
> >                 printk(KERN_INFO "using mwait in idle threads.\n");
> > -               pm_idle = mwait_idle;
> > +               local_idle = mwait_idle;
> >         } else if (check_c1e_idle(c)) {
> >                 printk(KERN_INFO "using C1E aware idle routine\n");
> > -               pm_idle = c1e_idle;
> > +               local_idle = c1e_idle;
> >         } else
> > -               pm_idle = default_idle;
> > +               local_idle = default_idle;
> > +
> > +       return;
> >  }
> >  
> >  void __init init_c1e_mask(void)
> >  {
> >         /* If we're using c1e_idle, we need to allocate c1e_mask. */
> > -       if (pm_idle == c1e_idle)
> > +       if (local_idle == c1e_idle)
> >                 zalloc_cpumask_var(&c1e_mask, GFP_KERNEL);
> >  }
> >  
> > @@ -556,7 +595,7 @@ static int __init idle_setup(char *str)
> >  
> >         if (!strcmp(str, "poll")) {
> >                 printk("using polling idle threads.\n");
> > -               pm_idle = poll_idle;
> > +               local_idle = poll_idle;
> >         } else if (!strcmp(str, "mwait"))
> >                 force_mwait = 1;
> >         else if (!strcmp(str, "halt")) {
> > @@ -567,7 +606,7 @@ static int __init idle_setup(char *str)
> >                  * To continue to load the CPU idle driver, don't touch
> >                  * the boot_option_idle_override.
> >                  */
> > -               pm_idle = default_idle;
> > +               local_idle = default_idle;
> >                 idle_halt = 1;
> >                 return 0;
> >         } else if (!strcmp(str, "nomwait")) {
> 
> 
> What guarantees that the cpuidle bits actually select this
> cpuidle_default driver when you do idle=poll?
> 

When we do a idle=poll, it sets boot_option_idle_override = 1, which
is checked during cpuidle_register_device in acpi/processor_idle.c

So cpuidle devices are not even registered if this option is set.

But, in acpi/processor_core.c where cpuidle_register_driver happens,
this check is not made currently. So, I guess this check must be added
before we register acpi_idle driver.

> Also, cpuidle already has a poll loop in it, why duplicate that?
>

Suppose the arch doesnt have a poll loop of its own, it can use the
one provided by cpuidle. I have just retained this from the earlier
implementation.

--arun

Re: [v7 PATCH 3/7]: x86: refactor x86 idle power management code and remove all instances of pm_idle.

[Arun R Bharadwaj]

* Peter Zijlstra <a.p.zijlstra@chello.nl> [2009-10-07 16:45:50]:

> On Tue, 2009-10-06 at 21:01 +0530, Arun R Bharadwaj wrote:
> > +++ linux.trees.git/arch/x86/kernel/process.c
> > @@ -9,6 +9,7 @@
> >  #include <linux/pm.h>
> >  #include <linux/clockchips.h>
> >  #include <linux/random.h>
> > +#include <linux/cpuidle.h>
> >  #include <trace/events/power.h>
> >  #include <asm/system.h>
> >  #include <asm/apic.h>
> > @@ -244,12 +245,6 @@ int sys_vfork(struct pt_regs *regs)
> >  unsigned long boot_option_idle_override = 0;
> >  EXPORT_SYMBOL(boot_option_idle_override);
> >  
> > -/*
> > - * Powermanagement idle function, if any..
> > - */
> > -void (*pm_idle)(void);
> > -EXPORT_SYMBOL(pm_idle);
> > -
> >  #ifdef CONFIG_X86_32
> >  /*
> >   * This halt magic was a workaround for ancient floppy DMA
> > @@ -329,17 +324,15 @@ static void do_nothing(void *unused)
> >  }
> >  
> >  /*
> > - * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
> > - * pm_idle and update to new pm_idle value. Required while changing pm_idle
> > - * handler on SMP systems.
> > + * cpu_idle_wait - Required while changing idle routine handler on SMP systems.
> >   *
> > - * Caller must have changed pm_idle to the new value before the call. Old
> > - * pm_idle value will not be used by any CPU after the return of this function.
> > + * Caller must have changed idle routine to the new value before the call. Old
> > + * value will not be used by any CPU after the return of this function.
> >   */
> >  void cpu_idle_wait(void)
> >  {
> >         smp_mb();
> > -       /* kick all the CPUs so that they exit out of pm_idle */
> > +       /* kick all the CPUs so that they exit out of idle loop */
> >         smp_call_function(do_nothing, NULL, 1);
> >  }
> >  EXPORT_SYMBOL_GPL(cpu_idle_wait);
> > @@ -518,15 +511,59 @@ static void c1e_idle(void)
> >                 default_idle();
> >  }
> >  
> > +static void (*local_idle)(void);
> > +DEFINE_PER_CPU(struct cpuidle_device, idle_devices);
> > +
> > +struct cpuidle_driver cpuidle_default_driver = {
> > +       .name =         "cpuidle_default",
> > +};
> > +
> > +static int local_idle_loop(struct cpuidle_device *dev, struct cpuidle_state *st)
> > +{
> > +       ktime_t t1, t2;
> > +       s64 diff;
> > +       int ret;
> > +
> > +       t1 = ktime_get();
> > +       local_idle();
> > +       t2 = ktime_get();
> > +
> > +       diff = ktime_to_us(ktime_sub(t2, t1));
> > +       if (diff > INT_MAX)
> > +               diff = INT_MAX;
> > +       ret = (int) diff;
> > +
> > +       return ret;
> > +}
> > +
> > +static int setup_cpuidle_simple(void)
> > +{
> > +       struct cpuidle_device *dev;
> > +       int cpu;
> > +
> > +       if (!cpuidle_curr_driver)
> > +               cpuidle_register_driver(&cpuidle_default_driver);
> > +
> > +       for_each_online_cpu(cpu) {
> > +               dev = &per_cpu(idle_devices, cpu);
> > +               dev->cpu = cpu;
> > +               dev->states[0].enter = local_idle_loop;
> > +               dev->state_count = 1;
> > +               cpuidle_register_device(dev);
> > +       }
> > +       return 0;
> > +}
> > +device_initcall(setup_cpuidle_simple);
> > +
> >  void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
> >  {
> >  #ifdef CONFIG_SMP
> > -       if (pm_idle == poll_idle && smp_num_siblings > 1) {
> > +       if (local_idle == poll_idle && smp_num_siblings > 1) {
> >                 printk(KERN_WARNING "WARNING: polling idle and HT enabled,"
> >                         " performance may degrade.\n");
> >         }
> >  #endif
> > -       if (pm_idle)
> > +       if (local_idle)
> >                 return;
> >  
> >         if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) {
> > @@ -534,18 +571,20 @@ void __cpuinit select_idle_routine(const
> >                  * One CPU supports mwait => All CPUs supports mwait
> >                  */
> >                 printk(KERN_INFO "using mwait in idle threads.\n");
> > -               pm_idle = mwait_idle;
> > +               local_idle = mwait_idle;
> >         } else if (check_c1e_idle(c)) {
> >                 printk(KERN_INFO "using C1E aware idle routine\n");
> > -               pm_idle = c1e_idle;
> > +               local_idle = c1e_idle;
> >         } else
> > -               pm_idle = default_idle;
> > +               local_idle = default_idle;
> > +
> > +       return;
> >  }
> >  
> >  void __init init_c1e_mask(void)
> >  {
> >         /* If we're using c1e_idle, we need to allocate c1e_mask. */
> > -       if (pm_idle == c1e_idle)
> > +       if (local_idle == c1e_idle)
> >                 zalloc_cpumask_var(&c1e_mask, GFP_KERNEL);
> >  }
> >  
> > @@ -556,7 +595,7 @@ static int __init idle_setup(char *str)
> >  
> >         if (!strcmp(str, "poll")) {
> >                 printk("using polling idle threads.\n");
> > -               pm_idle = poll_idle;
> > +               local_idle = poll_idle;
> >         } else if (!strcmp(str, "mwait"))
> >                 force_mwait = 1;
> >         else if (!strcmp(str, "halt")) {
> > @@ -567,7 +606,7 @@ static int __init idle_setup(char *str)
> >                  * To continue to load the CPU idle driver, don't touch
> >                  * the boot_option_idle_override.
> >                  */
> > -               pm_idle = default_idle;
> > +               local_idle = default_idle;
> >                 idle_halt = 1;
> >                 return 0;
> >         } else if (!strcmp(str, "nomwait")) {
> 
> 
> What guarantees that the cpuidle bits actually select this
> cpuidle_default driver when you do idle=poll?
> 
> Also, cpuidle already has a poll loop in it, why duplicate that?
> 

Yes, now i see it.. I'll get rid of the redundant poll_idle definition

[v7 PATCH 4/7]: POWER: enable cpuidle for POWER.

[Arun R Bharadwaj]

* Arun R Bharadwaj <arun@linux.vnet.ibm.com> [2009-10-06 20:54:21]:

This patch enables the cpuidle option in Kconfig for pSeries.

Currently cpuidle infrastructure is enabled only for x86 and ARM.
This code is almost completely borrowed from x86 to enable
cpuidle for pSeries.

Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com>
---
 arch/powerpc/Kconfig              |   17 +++++++++++++++++
 arch/powerpc/include/asm/system.h |    2 ++
 arch/powerpc/kernel/idle.c        |   19 +++++++++++++++++++
 3 files changed, 38 insertions(+)

Index: linux.trees.git/arch/powerpc/Kconfig
===================================================================
--- linux.trees.git.orig/arch/powerpc/Kconfig
+++ linux.trees.git/arch/powerpc/Kconfig
@@ -88,6 +88,9 @@ config ARCH_HAS_ILOG2_U64
 	bool
 	default y if 64BIT
 
+config ARCH_HAS_CPU_IDLE_WAIT
+	def_bool y
+
 config GENERIC_HWEIGHT
 	bool
 	default y
@@ -243,6 +246,20 @@ source "kernel/Kconfig.freezer"
 source "arch/powerpc/sysdev/Kconfig"
 source "arch/powerpc/platforms/Kconfig"
 
+menu "Power management options"
+
+source "drivers/cpuidle/Kconfig"
+
+config PSERIES_PROCESSOR_IDLE
+	bool "Idle Power Management Support for pSeries"
+	depends on PPC_PSERIES && CPU_IDLE
+	default y
+	help
+	  Idle Power Management Support for pSeries. This hooks onto cpuidle
+	  infrastructure to help in idle cpu power management.
+
+endmenu
+
 menu "Kernel options"
 
 config HIGHMEM
Index: linux.trees.git/arch/powerpc/include/asm/system.h
===================================================================
--- linux.trees.git.orig/arch/powerpc/include/asm/system.h
+++ linux.trees.git/arch/powerpc/include/asm/system.h
@@ -546,5 +546,7 @@ extern void account_system_vtime(struct 
 
 extern struct dentry *powerpc_debugfs_root;
 
+void cpu_idle_wait(void);
+
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_SYSTEM_H */
Index: linux.trees.git/arch/powerpc/kernel/idle.c
===================================================================
--- linux.trees.git.orig/arch/powerpc/kernel/idle.c
+++ linux.trees.git/arch/powerpc/kernel/idle.c
@@ -102,6 +102,25 @@ void cpu_idle(void)
 	}
 }
 
+static void do_nothing(void *unused)
+{
+}
+
+/*
+ * cpu_idle_wait - Used to ensure that all the CPUs come out of the old
+ * idle loop and start using the new idle loop.
+ * Required while changing idle handler on SMP systems.
+ * Caller must have changed idle handler to the new value before the call.
+ */
+void cpu_idle_wait(void)
+{
+	/* Ensure that new value of ppc_md.power_save is set */
+	smp_mb();
+	/* kick all the CPUs so that they exit out of ppc_md.power_save */
+	smp_call_function(do_nothing, NULL, 1);
+}
+EXPORT_SYMBOL_GPL(cpu_idle_wait);
+
 int powersave_nap;
 
 #ifdef CONFIG_SYSCTL

[v7 PATCH 5/7]: pSeries/cpuidle: remove dedicate/shared idle loops, which will be moved to arch/powerpc/platforms/pseries/processor_idle.c.

[Arun R Bharadwaj]

* Arun R Bharadwaj <arun@linux.vnet.ibm.com> [2009-10-06 20:54:21]:

This patch removes the routines, pseries_shared_idle_sleep and
pseries_dedicated_idle_sleep, since this is implemented as a part
of arch/powerpc/platform/pseries/processor_idle.c

Also, similar to x86, call cpuidle_idle_call from cpu_idle() idle
loop instead of ppc_md.power_save.


Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com>
---
 arch/powerpc/kernel/idle.c             |   50 +++++++-----------
 arch/powerpc/platforms/pseries/setup.c |   89 ---------------------------------
 2 files changed, 22 insertions(+), 117 deletions(-)

Index: linux.trees.git/arch/powerpc/platforms/pseries/setup.c
===================================================================
--- linux.trees.git.orig/arch/powerpc/platforms/pseries/setup.c
+++ linux.trees.git/arch/powerpc/platforms/pseries/setup.c
@@ -75,9 +75,6 @@ EXPORT_SYMBOL(CMO_PageSize);
 
 int fwnmi_active;  /* TRUE if an FWNMI handler is present */
 
-static void pseries_shared_idle_sleep(void);
-static void pseries_dedicated_idle_sleep(void);
-
 static struct device_node *pSeries_mpic_node;
 
 static void pSeries_show_cpuinfo(struct seq_file *m)
@@ -301,18 +298,8 @@ static void __init pSeries_setup_arch(vo
 	pSeries_nvram_init();
 
 	/* Choose an idle loop */
-	if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
+	if (firmware_has_feature(FW_FEATURE_SPLPAR))
 		vpa_init(boot_cpuid);
-		if (get_lppaca()->shared_proc) {
-			printk(KERN_DEBUG "Using shared processor idle loop\n");
-			ppc_md.power_save = pseries_shared_idle_sleep;
-		} else {
-			printk(KERN_DEBUG "Using dedicated idle loop\n");
-			ppc_md.power_save = pseries_dedicated_idle_sleep;
-		}
-	} else {
-		printk(KERN_DEBUG "Using default idle loop\n");
-	}
 
 	if (firmware_has_feature(FW_FEATURE_LPAR))
 		ppc_md.enable_pmcs = pseries_lpar_enable_pmcs;
@@ -500,80 +487,6 @@ static int __init pSeries_probe(void)
 	return 1;
 }
 
-
-DECLARE_PER_CPU(unsigned long, smt_snooze_delay);
-
-static void pseries_dedicated_idle_sleep(void)
-{ 
-	unsigned int cpu = smp_processor_id();
-	unsigned long start_snooze;
-	unsigned long in_purr, out_purr;
-
-	/*
-	 * Indicate to the HV that we are idle. Now would be
-	 * a good time to find other work to dispatch.
-	 */
-	get_lppaca()->idle = 1;
-	get_lppaca()->donate_dedicated_cpu = 1;
-	in_purr = mfspr(SPRN_PURR);
-
-	/*
-	 * We come in with interrupts disabled, and need_resched()
-	 * has been checked recently.  If we should poll for a little
-	 * while, do so.
-	 */
-	if (__get_cpu_var(smt_snooze_delay)) {
-		start_snooze = get_tb() +
-			__get_cpu_var(smt_snooze_delay) * tb_ticks_per_usec;
-		local_irq_enable();
-		set_thread_flag(TIF_POLLING_NRFLAG);
-
-		while (get_tb() < start_snooze) {
-			if (need_resched() || cpu_is_offline(cpu))
-				goto out;
-			ppc64_runlatch_off();
-			HMT_low();
-			HMT_very_low();
-		}
-
-		HMT_medium();
-		clear_thread_flag(TIF_POLLING_NRFLAG);
-		smp_mb();
-		local_irq_disable();
-		if (need_resched() || cpu_is_offline(cpu))
-			goto out;
-	}
-
-	cede_processor();
-
-out:
-	HMT_medium();
-	out_purr = mfspr(SPRN_PURR);
-	get_lppaca()->wait_state_cycles += out_purr - in_purr;
-	get_lppaca()->donate_dedicated_cpu = 0;
-	get_lppaca()->idle = 0;
-}
-
-static void pseries_shared_idle_sleep(void)
-{
-	/*
-	 * Indicate to the HV that we are idle. Now would be
-	 * a good time to find other work to dispatch.
-	 */
-	get_lppaca()->idle = 1;
-
-	/*
-	 * Yield the processor to the hypervisor.  We return if
-	 * an external interrupt occurs (which are driven prior
-	 * to returning here) or if a prod occurs from another
-	 * processor. When returning here, external interrupts
-	 * are enabled.
-	 */
-	cede_processor();
-
-	get_lppaca()->idle = 0;
-}
-
 static int pSeries_pci_probe_mode(struct pci_bus *bus)
 {
 	if (firmware_has_feature(FW_FEATURE_LPAR))
Index: linux.trees.git/arch/powerpc/kernel/idle.c
===================================================================
--- linux.trees.git.orig/arch/powerpc/kernel/idle.c
+++ linux.trees.git/arch/powerpc/kernel/idle.c
@@ -25,6 +25,7 @@
 #include <linux/cpu.h>
 #include <linux/sysctl.h>
 #include <linux/tick.h>
+#include <linux/cpuidle.h>
 
 #include <asm/system.h>
 #include <asm/processor.h>
@@ -60,35 +61,26 @@ void cpu_idle(void)
 		while (!need_resched() && !cpu_should_die()) {
 			ppc64_runlatch_off();
 
-			if (ppc_md.power_save) {
-				clear_thread_flag(TIF_POLLING_NRFLAG);
-				/*
-				 * smp_mb is so clearing of TIF_POLLING_NRFLAG
-				 * is ordered w.r.t. need_resched() test.
-				 */
-				smp_mb();
-				local_irq_disable();
-
-				/* Don't trace irqs off for idle */
-				stop_critical_timings();
-
-				/* check again after disabling irqs */
-				if (!need_resched() && !cpu_should_die())
-					ppc_md.power_save();
-
-				start_critical_timings();
-
-				local_irq_enable();
-				set_thread_flag(TIF_POLLING_NRFLAG);
-
-			} else {
-				/*
-				 * Go into low thread priority and possibly
-				 * low power mode.
-				 */
-				HMT_low();
-				HMT_very_low();
-			}
+			clear_thread_flag(TIF_POLLING_NRFLAG);
+			/*
+			 * smp_mb is so clearing of TIF_POLLING_NRFLAG
+			 * is ordered w.r.t. need_resched() test.
+			 */
+			smp_mb();
+			local_irq_disable();
+
+			/* Don't trace irqs off for idle */
+			stop_critical_timings();
+
+			/* check again after disabling irqs */
+			if (!need_resched() && !cpu_should_die())
+				cpuidle_idle_call();
+
+			start_critical_timings();
+
+			local_irq_enable();
+			set_thread_flag(TIF_POLLING_NRFLAG);
+
 		}
 
 		HMT_medium();

[v7 PATCH 6/7]: POWER: add a default_idle idle loop for POWER.

[Arun R Bharadwaj]

* Arun R Bharadwaj <arun@linux.vnet.ibm.com> [2009-10-06 20:54:21]:

In arch/powerpc/kernel/idle.c create a default_idle() routine by moving
the failover condition of the cpu_idle() idle loop. This is needed by
cpuidle infrastructure to call default_idle when other idle routines
are not yet registered. Functionality remains the same, but the code is
slightly moved around.


Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com>
---
 arch/powerpc/Kconfig              |    3 +++
 arch/powerpc/include/asm/system.h |    1 +
 arch/powerpc/kernel/idle.c        |    6 ++++++
 3 files changed, 10 insertions(+)

Index: linux.trees.git/arch/powerpc/Kconfig
===================================================================
--- linux.trees.git.orig/arch/powerpc/Kconfig
+++ linux.trees.git/arch/powerpc/Kconfig
@@ -91,6 +91,9 @@ config ARCH_HAS_ILOG2_U64
 config ARCH_HAS_CPU_IDLE_WAIT
 	def_bool y
 
+config ARCH_HAS_DEFAULT_IDLE
+	def_bool y
+
 config GENERIC_HWEIGHT
 	bool
 	default y
Index: linux.trees.git/arch/powerpc/include/asm/system.h
===================================================================
--- linux.trees.git.orig/arch/powerpc/include/asm/system.h
+++ linux.trees.git/arch/powerpc/include/asm/system.h
@@ -218,6 +218,7 @@ extern unsigned long klimit;
 extern void *alloc_maybe_bootmem(size_t size, gfp_t mask);
 extern void *zalloc_maybe_bootmem(size_t size, gfp_t mask);
 
+extern void default_idle(void);
 extern int powersave_nap;	/* set if nap mode can be used in idle loop */
 
 /*
Index: linux.trees.git/arch/powerpc/kernel/idle.c
===================================================================
--- linux.trees.git.orig/arch/powerpc/kernel/idle.c
+++ linux.trees.git/arch/powerpc/kernel/idle.c
@@ -113,6 +113,12 @@ void cpu_idle_wait(void)
 }
 EXPORT_SYMBOL_GPL(cpu_idle_wait);
 
+void default_idle(void)
+{
+	HMT_low();
+	HMT_very_low();
+}
+
 int powersave_nap;
 
 #ifdef CONFIG_SYSCTL

[v7 PATCH 7/7]: pSeries: implement pSeries processor idle module.

[Arun R Bharadwaj]

* Arun R Bharadwaj <arun@linux.vnet.ibm.com> [2009-10-06 20:54:21]:

This patch creates arch/powerpc/platforms/pseries/processor_idle.c,
which implements the cpuidle infrastructure for pseries.
It implements a pseries_cpuidle_loop() which would be the main idle loop
called from cpu_idle(). It makes decision of entering either
dedicated_snooze_loop or dedicated_cede_loop for dedicated lpar and
shared_cede_loop for shared lpar processor based on the
decision taken by the cpuidle governor.

Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/system.h               |    1 
 arch/powerpc/kernel/sysfs.c                     |    2 
 arch/powerpc/platforms/pseries/Makefile         |    1 
 arch/powerpc/platforms/pseries/processor_idle.c |  208 ++++++++++++++++++++++++
 arch/powerpc/platforms/pseries/pseries.h        |    8 
 5 files changed, 220 insertions(+)

Index: linux.trees.git/arch/powerpc/platforms/pseries/Makefile
===================================================================
--- linux.trees.git.orig/arch/powerpc/platforms/pseries/Makefile
+++ linux.trees.git/arch/powerpc/platforms/pseries/Makefile
@@ -26,3 +26,4 @@ obj-$(CONFIG_HCALL_STATS)	+= hvCall_inst
 obj-$(CONFIG_PHYP_DUMP)	+= phyp_dump.o
 obj-$(CONFIG_CMM)		+= cmm.o
 obj-$(CONFIG_DTL)		+= dtl.o
+obj-$(CONFIG_PSERIES_PROCESSOR_IDLE)	+= processor_idle.o
Index: linux.trees.git/arch/powerpc/platforms/pseries/pseries.h
===================================================================
--- linux.trees.git.orig/arch/powerpc/platforms/pseries/pseries.h
+++ linux.trees.git/arch/powerpc/platforms/pseries/pseries.h
@@ -10,6 +10,8 @@
 #ifndef _PSERIES_PSERIES_H
 #define _PSERIES_PSERIES_H
 
+#include <linux/cpuidle.h>
+
 extern void __init fw_feature_init(const char *hypertas, unsigned long len);
 
 struct pt_regs;
@@ -40,4 +42,10 @@ extern unsigned long rtas_poweron_auto;
 
 extern void find_udbg_vterm(void);
 
+DECLARE_PER_CPU(unsigned long, smt_snooze_delay);
+
+#ifdef CONFIG_PSERIES_PROCESSOR_IDLE
+extern struct cpuidle_driver pseries_idle_driver;
+#endif
+
 #endif /* _PSERIES_PSERIES_H */
Index: linux.trees.git/arch/powerpc/platforms/pseries/processor_idle.c
===================================================================
--- /dev/null
+++ linux.trees.git/arch/powerpc/platforms/pseries/processor_idle.c
@@ -0,0 +1,208 @@
+/*
+ *  processor_idle - idle state cpuidle driver.
+ *  Adapted from drivers/acpi/processor_idle.c
+ *
+ *  Arun R Bharadwaj <arun@linux.vnet.ibm.com>
+ *
+ *  Copyright (C) 2009 IBM Corporation.
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or (at
+ *  your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but
+ *  WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/moduleparam.h>
+#include <linux/cpuidle.h>
+
+#include <asm/paca.h>
+#include <asm/reg.h>
+#include <asm/system.h>
+#include <asm/machdep.h>
+#include <asm/firmware.h>
+
+#include "plpar_wrappers.h"
+#include "pseries.h"
+
+MODULE_AUTHOR("Arun R Bharadwaj");
+MODULE_DESCRIPTION("pSeries Idle State Driver");
+MODULE_LICENSE("GPL");
+
+struct cpuidle_driver pseries_idle_driver = {
+	.name =		"pseries_idle",
+	.owner =	THIS_MODULE,
+};
+
+DEFINE_PER_CPU(struct cpuidle_device, pseries_dev);
+
+#define IDLE_STATE_COUNT	2
+
+/* pSeries Idle state Flags */
+#define	PSERIES_DEDICATED_SNOOZE	(0x01)
+#define	PSERIES_DEDICATED_CEDE		(0x02)
+#define	PSERIES_SHARED_CEDE		(0x03)
+
+static int pseries_idle_init(struct cpuidle_device *dev)
+{
+	return cpuidle_register_device(dev);
+}
+
+static void shared_cede_loop(void)
+{
+	get_lppaca()->idle = 1;
+	cede_processor();
+	get_lppaca()->idle = 0;
+}
+
+static void dedicated_snooze_loop(void)
+{
+	local_irq_enable();
+	set_thread_flag(TIF_POLLING_NRFLAG);
+	while (!need_resched()) {
+		ppc64_runlatch_off();
+		HMT_low();
+		HMT_very_low();
+	}
+	HMT_medium();
+	clear_thread_flag(TIF_POLLING_NRFLAG);
+	smp_mb();
+	local_irq_disable();
+}
+
+static void dedicated_cede_loop(void)
+{
+	ppc64_runlatch_off();
+	HMT_medium();
+	cede_processor();
+}
+
+static int pseries_cpuidle_loop(struct cpuidle_device *dev,
+				struct cpuidle_state *st)
+{
+	ktime_t t1, t2;
+	s64 diff;
+	int ret;
+	unsigned long in_purr, out_purr;
+
+	get_lppaca()->idle = 1;
+	get_lppaca()->donate_dedicated_cpu = 1;
+	in_purr = mfspr(SPRN_PURR);
+
+	t1 = ktime_get();
+
+	if (st->flags & PSERIES_SHARED_CEDE)
+		shared_cede_loop();
+	else if (st->flags & PSERIES_DEDICATED_SNOOZE)
+		dedicated_snooze_loop();
+	else
+		dedicated_cede_loop();
+
+	t2 = ktime_get();
+	diff = ktime_to_us(ktime_sub(t2, t1));
+	if (diff > INT_MAX)
+		diff = INT_MAX;
+
+	ret = (int) diff;
+
+	out_purr = mfspr(SPRN_PURR);
+	get_lppaca()->wait_state_cycles += out_purr - in_purr;
+	get_lppaca()->donate_dedicated_cpu = 0;
+	get_lppaca()->idle = 0;
+
+	return ret;
+}
+
+static int pseries_setup_cpuidle(struct cpuidle_device *dev, int cpu)
+{
+	int i;
+	struct cpuidle_state *state;
+
+	dev->cpu = cpu;
+
+	if (get_lppaca()->shared_proc) {
+		state = &dev->states[0];
+		snprintf(state->name, CPUIDLE_NAME_LEN, "IDLE");
+		state->enter = pseries_cpuidle_loop;
+		strncpy(state->desc, "shared_cede", CPUIDLE_DESC_LEN);
+		state->flags = PSERIES_SHARED_CEDE;
+		state->exit_latency = 0;
+		state->target_residency = 0;
+		return 0;
+	}
+
+	for (i = 0; i < IDLE_STATE_COUNT; i++) {
+		state = &dev->states[i];
+
+		snprintf(state->name, CPUIDLE_NAME_LEN, "CEDE%d", i);
+		state->enter = pseries_cpuidle_loop;
+
+		switch (i) {
+		case 0:
+			strncpy(state->desc, "snooze", CPUIDLE_DESC_LEN);
+			state->flags = PSERIES_DEDICATED_SNOOZE;
+			state->exit_latency = 0;
+			state->target_residency = 0;
+			break;
+
+		case 1:
+			strncpy(state->desc, "cede", CPUIDLE_DESC_LEN);
+			state->flags = PSERIES_DEDICATED_CEDE;
+			state->exit_latency = 1;
+			state->target_residency =
+					__get_cpu_var(smt_snooze_delay);
+			break;
+		}
+	}
+	dev->state_count = IDLE_STATE_COUNT;
+
+	return 0;
+}
+
+void update_smt_snooze_delay(int snooze)
+{
+	int cpu;
+	for_each_online_cpu(cpu)
+		per_cpu(pseries_dev, cpu).states[0].target_residency = snooze;
+}
+
+static int __init pseries_processor_idle_init(void)
+{
+	int cpu;
+	int result = cpuidle_register_driver(&pseries_idle_driver);
+
+	if (result < 0)
+		return result;
+
+	printk(KERN_DEBUG "pSeries idle driver registered\n");
+
+	if (!firmware_has_feature(FW_FEATURE_SPLPAR)) {
+		printk(KERN_DEBUG "Using default idle\n");
+		return 0;
+	}
+
+	for_each_online_cpu(cpu) {
+		pseries_setup_cpuidle(&per_cpu(pseries_dev, cpu), cpu);
+		pseries_idle_init(&per_cpu(pseries_dev, cpu));
+	}
+
+	printk(KERN_DEBUG "Using cpuidle idle loop\n");
+
+	return 0;
+}
+
+late_initcall(pseries_processor_idle_init);
Index: linux.trees.git/arch/powerpc/include/asm/system.h
===================================================================
--- linux.trees.git.orig/arch/powerpc/include/asm/system.h
+++ linux.trees.git/arch/powerpc/include/asm/system.h
@@ -548,6 +548,7 @@ extern void account_system_vtime(struct 
 extern struct dentry *powerpc_debugfs_root;
 
 void cpu_idle_wait(void);
+extern void update_smt_snooze_delay(int snooze);
 
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_SYSTEM_H */
Index: linux.trees.git/arch/powerpc/kernel/sysfs.c
===================================================================
--- linux.trees.git.orig/arch/powerpc/kernel/sysfs.c
+++ linux.trees.git/arch/powerpc/kernel/sysfs.c
@@ -18,6 +18,7 @@
 #include <asm/machdep.h>
 #include <asm/smp.h>
 #include <asm/pmc.h>
+#include <asm/system.h>
 
 #include "cacheinfo.h"
 
@@ -51,6 +52,7 @@ static ssize_t store_smt_snooze_delay(st
 		return -EINVAL;
 
 	per_cpu(smt_snooze_delay, cpu->sysdev.id) = snooze;
+	update_smt_snooze_delay(snooze);
 
 	return count;
 }

Re: [v7 PATCH 7/7]: pSeries: implement pSeries processor idle module.

[Arun R Bharadwaj]

* Arun R Bharadwaj <arun@linux.vnet.ibm.com> [2009-10-06 21:05:22]:

> * Arun R Bharadwaj <arun@linux.vnet.ibm.com> [2009-10-06 20:54:21]:

Please consider this updated PATCH 7/7 instead of the earlier one.
The earlier one had a late_initcall(pseries_processor_idle_init),
which caused a panic when cpuidle_enable_device() was called from
cpuidle_switch_governor(). This is because registration of cpuidle
devices was happening at a later stage. So change this to a
device_initcall() to get rid of the panic.

---

This patch creates arch/powerpc/platforms/pseries/processor_idle.c,
which implements the cpuidle infrastructure for pseries.
It implements a pseries_cpuidle_loop() which would be the main idle loop
called from cpu_idle(). It makes decision of entering either
dedicated_snooze_loop or dedicated_cede_loop for dedicated lpar and
shared_cede_loop for shared lpar processor based on the
decision taken by the cpuidle governor.

Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/system.h               |    1 
 arch/powerpc/kernel/sysfs.c                     |    2 
 arch/powerpc/platforms/pseries/Makefile         |    1 
 arch/powerpc/platforms/pseries/processor_idle.c |  208 ++++++++++++++++++++++++
 arch/powerpc/platforms/pseries/pseries.h        |    8 
 5 files changed, 220 insertions(+)

Index: linux.trees.git/arch/powerpc/platforms/pseries/Makefile
===================================================================
--- linux.trees.git.orig/arch/powerpc/platforms/pseries/Makefile
+++ linux.trees.git/arch/powerpc/platforms/pseries/Makefile
@@ -26,3 +26,4 @@ obj-$(CONFIG_HCALL_STATS)	+= hvCall_inst
 obj-$(CONFIG_PHYP_DUMP)	+= phyp_dump.o
 obj-$(CONFIG_CMM)		+= cmm.o
 obj-$(CONFIG_DTL)		+= dtl.o
+obj-$(CONFIG_PSERIES_PROCESSOR_IDLE)	+= processor_idle.o
Index: linux.trees.git/arch/powerpc/platforms/pseries/pseries.h
===================================================================
--- linux.trees.git.orig/arch/powerpc/platforms/pseries/pseries.h
+++ linux.trees.git/arch/powerpc/platforms/pseries/pseries.h
@@ -10,6 +10,8 @@
 #ifndef _PSERIES_PSERIES_H
 #define _PSERIES_PSERIES_H
 
+#include <linux/cpuidle.h>
+
 extern void __init fw_feature_init(const char *hypertas, unsigned long len);
 
 struct pt_regs;
@@ -40,4 +42,10 @@ extern unsigned long rtas_poweron_auto;
 
 extern void find_udbg_vterm(void);
 
+DECLARE_PER_CPU(unsigned long, smt_snooze_delay);
+
+#ifdef CONFIG_PSERIES_PROCESSOR_IDLE
+extern struct cpuidle_driver pseries_idle_driver;
+#endif
+
 #endif /* _PSERIES_PSERIES_H */
Index: linux.trees.git/arch/powerpc/platforms/pseries/processor_idle.c
===================================================================
--- /dev/null
+++ linux.trees.git/arch/powerpc/platforms/pseries/processor_idle.c
@@ -0,0 +1,208 @@
+/*
+ *  processor_idle - idle state cpuidle driver.
+ *  Adapted from drivers/acpi/processor_idle.c
+ *
+ *  Arun R Bharadwaj <arun@linux.vnet.ibm.com>
+ *
+ *  Copyright (C) 2009 IBM Corporation.
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or (at
+ *  your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but
+ *  WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/moduleparam.h>
+#include <linux/cpuidle.h>
+
+#include <asm/paca.h>
+#include <asm/reg.h>
+#include <asm/system.h>
+#include <asm/machdep.h>
+#include <asm/firmware.h>
+
+#include "plpar_wrappers.h"
+#include "pseries.h"
+
+MODULE_AUTHOR("Arun R Bharadwaj");
+MODULE_DESCRIPTION("pSeries Idle State Driver");
+MODULE_LICENSE("GPL");
+
+struct cpuidle_driver pseries_idle_driver = {
+	.name =		"pseries_idle",
+	.owner =	THIS_MODULE,
+};
+
+DEFINE_PER_CPU(struct cpuidle_device, pseries_dev);
+
+#define IDLE_STATE_COUNT	2
+
+/* pSeries Idle state Flags */
+#define	PSERIES_DEDICATED_SNOOZE	(0x01)
+#define	PSERIES_DEDICATED_CEDE		(0x02)
+#define	PSERIES_SHARED_CEDE		(0x03)
+
+static int pseries_idle_init(struct cpuidle_device *dev)
+{
+	return cpuidle_register_device(dev);
+}
+
+static void shared_cede_loop(void)
+{
+	get_lppaca()->idle = 1;
+	cede_processor();
+	get_lppaca()->idle = 0;
+}
+
+static void dedicated_snooze_loop(void)
+{
+	local_irq_enable();
+	set_thread_flag(TIF_POLLING_NRFLAG);
+	while (!need_resched()) {
+		ppc64_runlatch_off();
+		HMT_low();
+		HMT_very_low();
+	}
+	HMT_medium();
+	clear_thread_flag(TIF_POLLING_NRFLAG);
+	smp_mb();
+	local_irq_disable();
+}
+
+static void dedicated_cede_loop(void)
+{
+	ppc64_runlatch_off();
+	HMT_medium();
+	cede_processor();
+}
+
+static int pseries_cpuidle_loop(struct cpuidle_device *dev,
+				struct cpuidle_state *st)
+{
+	ktime_t t1, t2;
+	s64 diff;
+	int ret;
+	unsigned long in_purr, out_purr;
+
+	get_lppaca()->idle = 1;
+	get_lppaca()->donate_dedicated_cpu = 1;
+	in_purr = mfspr(SPRN_PURR);
+
+	t1 = ktime_get();
+
+	if (st->flags & PSERIES_SHARED_CEDE)
+		shared_cede_loop();
+	else if (st->flags & PSERIES_DEDICATED_SNOOZE)
+		dedicated_snooze_loop();
+	else
+		dedicated_cede_loop();
+
+	t2 = ktime_get();
+	diff = ktime_to_us(ktime_sub(t2, t1));
+	if (diff > INT_MAX)
+		diff = INT_MAX;
+
+	ret = (int) diff;
+
+	out_purr = mfspr(SPRN_PURR);
+	get_lppaca()->wait_state_cycles += out_purr - in_purr;
+	get_lppaca()->donate_dedicated_cpu = 0;
+	get_lppaca()->idle = 0;
+
+	return ret;
+}
+
+static int pseries_setup_cpuidle(struct cpuidle_device *dev, int cpu)
+{
+	int i;
+	struct cpuidle_state *state;
+
+	dev->cpu = cpu;
+
+	if (get_lppaca()->shared_proc) {
+		state = &dev->states[0];
+		snprintf(state->name, CPUIDLE_NAME_LEN, "IDLE");
+		state->enter = pseries_cpuidle_loop;
+		strncpy(state->desc, "shared_cede", CPUIDLE_DESC_LEN);
+		state->flags = PSERIES_SHARED_CEDE;
+		state->exit_latency = 0;
+		state->target_residency = 0;
+		return 0;
+	}
+
+	for (i = 0; i < IDLE_STATE_COUNT; i++) {
+		state = &dev->states[i];
+
+		snprintf(state->name, CPUIDLE_NAME_LEN, "CEDE%d", i);
+		state->enter = pseries_cpuidle_loop;
+
+		switch (i) {
+		case 0:
+			strncpy(state->desc, "snooze", CPUIDLE_DESC_LEN);
+			state->flags = PSERIES_DEDICATED_SNOOZE;
+			state->exit_latency = 0;
+			state->target_residency = 0;
+			break;
+
+		case 1:
+			strncpy(state->desc, "cede", CPUIDLE_DESC_LEN);
+			state->flags = PSERIES_DEDICATED_CEDE;
+			state->exit_latency = 1;
+			state->target_residency =
+					__get_cpu_var(smt_snooze_delay);
+			break;
+		}
+	}
+	dev->state_count = IDLE_STATE_COUNT;
+
+	return 0;
+}
+
+void update_smt_snooze_delay(int snooze)
+{
+	int cpu;
+	for_each_online_cpu(cpu)
+		per_cpu(pseries_dev, cpu).states[0].target_residency = snooze;
+}
+
+static int __init pseries_processor_idle_init(void)
+{
+	int cpu;
+	int result = cpuidle_register_driver(&pseries_idle_driver);
+
+	if (result < 0)
+		return result;
+
+	printk(KERN_DEBUG "pSeries idle driver registered\n");
+
+	if (!firmware_has_feature(FW_FEATURE_SPLPAR)) {
+		printk(KERN_DEBUG "Using default idle\n");
+		return 0;
+	}
+
+	for_each_online_cpu(cpu) {
+		pseries_setup_cpuidle(&per_cpu(pseries_dev, cpu), cpu);
+		pseries_idle_init(&per_cpu(pseries_dev, cpu));
+	}
+
+	printk(KERN_DEBUG "Using cpuidle idle loop\n");
+
+	return 0;
+}
+
+device_initcall(pseries_processor_idle_init);
Index: linux.trees.git/arch/powerpc/include/asm/system.h
===================================================================
--- linux.trees.git.orig/arch/powerpc/include/asm/system.h
+++ linux.trees.git/arch/powerpc/include/asm/system.h
@@ -548,6 +548,7 @@ extern void account_system_vtime(struct 
 extern struct dentry *powerpc_debugfs_root;
 
 void cpu_idle_wait(void);
+extern void update_smt_snooze_delay(int snooze);
 
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_SYSTEM_H */
Index: linux.trees.git/arch/powerpc/kernel/sysfs.c
===================================================================
--- linux.trees.git.orig/arch/powerpc/kernel/sysfs.c
+++ linux.trees.git/arch/powerpc/kernel/sysfs.c
@@ -18,6 +18,7 @@
 #include <asm/machdep.h>
 #include <asm/smp.h>
 #include <asm/pmc.h>
+#include <asm/system.h>
 
 #include "cacheinfo.h"
 
@@ -51,6 +52,7 @@ static ssize_t store_smt_snooze_delay(st
 		return -EINVAL;
 
 	per_cpu(smt_snooze_delay, cpu->sysdev.id) = snooze;
+	update_smt_snooze_delay(snooze);
 
 	return count;
 }

Re: [v7 PATCH 0/7]: cpuidle/x86/POWER: Cleanup idle power management code in x86, cleanup drivers/cpuidle/cpuidle.c and introduce cpuidle to POWER.

[Arun R Bharadwaj]

* Arun R Bharadwaj <arun@linux.vnet.ibm.com> [2009-10-06 20:54:21]:

> Hi
> 
> Please consider this for inclusion into the testing tree.
> 
> This patchset introduces cpuidle infrastructure to POWER, prototyping
> for pSeries, and also does a major refactoring of current x86 idle
> power management and a cleanup of cpuidle infrastructure.
> 
> Earlier discussions on the same can be found at:
> 
> v6 --> http://lkml.org/lkml/2009/9/22/180
> v5 --> http://lkml.org/lkml/2009/9/22/26
> v4 --> http://lkml.org/lkml/2009/9/1/133
> v3 --> http://lkml.org/lkml/2009/8/27/124
> v2 --> http://lkml.org/lkml/2009/8/26/233
> v1 --> http://lkml.org/lkml/2009/8/19/150
> 
> 
> Changes in this version:
> -----------------------------------------
> 
> * Earlier implementation maintained a list of cpuidle devices and
>   the list was traversed to disable and enable the cpuidle devices
>   when switching governors. This list is not necessary and is removed.
>   Now, we get the per cpu structure cpuidle_devices and disable and
>   enable it for each online cpu while switching governors.
> 
> * Earlier iterations were buggy w.r.t the sysfs interface of the cpuidle.
>   This iteration removes the bug in PATCH 1/7.
> 
> * In PATCH 7/7, smt_snooze_delay was not being updated whenever it was
>   changed through the sysfs interface. Provide a helper routine to
>   update it.
> 
> * In PATCH 7/7, the idle loops are renamed to denote the idle states
>   to avoid any confusion.
> 

Also, the per-cpu nature of registration/unregistration of cpuidle
has been maintained as ACPI needs this.

> 
> thanks,
> arun

Re: [v7 PATCH 0/7]: cpuidle/x86/POWER: Cleanup idle power management code in x86, cleanup drivers/cpuidle/cpuidle.c and introduce cpuidle to POWER.

[Peter Zijlstra]

On Tue, 2009-10-06 at 22:05 +0530, Arun R Bharadwaj wrote:

> Also, the per-cpu nature of registration/unregistration of cpuidle
> has been maintained as ACPI needs this.

Right, so can't we ditch that and have acpi default to the lowest common
C-state and warn when various cpus report different C-states?

Re: [v7 PATCH 0/7]: cpuidle/x86/POWER: Cleanup idle power management code in x86, cleanup drivers/cpuidle/cpuidle.c and introduce cpuidle to POWER.

[Vaidyanathan Srinivasan]

* Peter Zijlstra <a.p.zijlstra@chello.nl> [2009-10-06 20:04:39]:

> On Tue, 2009-10-06 at 22:05 +0530, Arun R Bharadwaj wrote:
> 
> > Also, the per-cpu nature of registration/unregistration of cpuidle
> > has been maintained as ACPI needs this.
> 
> Right, so can't we ditch that and have acpi default to the lowest common
> C-state and warn when various cpus report different C-states?

Hi Peter,

As Arjan mentioned previously, the per-cpu registration has to stay
for x86 for now due to legacy ACPI compatibility.  Breaking that may
break lot of existing users and we do not have a clean fallback
method.  

As far as powerpc is concerned, we can work with a single global
registration.  However we would like to have the same interface across
different archs.

With the new re-factoring (v7), Arun has killed most of the list
traversal and linking between various cpu's cpuidle_driver structures.
Now we have a per-cpu stack of registered devices and we lookup the
structs using online cpumasks.  The cpuidle_driver structure has list
of idle routing pointers (struct cpuidle_state) and rest of it is
statistics that needs to be maintained at a per-cpu level anyway.  All
that is duplicated here is the array of idle routines (struct
cpuidle_state) on each cpu.

The objective of the refactoring is to have a single common idle
routine management framework (remove pm_idle) and we have it done
through cpuidle registration framework.  We can incrementally remove
the per-cpu registration later easily by splitting the cpuidle_driver
structure.

--Vaidy

Re: [v7 PATCH 0/7]: cpuidle/x86/POWER: Cleanup idle power management code in x86, cleanup drivers/cpuidle/cpuidle.c and introduce cpuidle to POWER.

[Balbir Singh]

* Vaidy <svaidy@linux.vnet.ibm.com> [2009-10-07 16:56:48]:

> * Peter Zijlstra <a.p.zijlstra@chello.nl> [2009-10-06 20:04:39]:
> 
> > On Tue, 2009-10-06 at 22:05 +0530, Arun R Bharadwaj wrote:
> > 
> > > Also, the per-cpu nature of registration/unregistration of cpuidle
> > > has been maintained as ACPI needs this.
> > 
> > Right, so can't we ditch that and have acpi default to the lowest common
> > C-state and warn when various cpus report different C-states?
> 
> Hi Peter,
> 
> As Arjan mentioned previously, the per-cpu registration has to stay
> for x86 for now due to legacy ACPI compatibility.  Breaking that may
> break lot of existing users and we do not have a clean fallback
> method.  
> 
> As far as powerpc is concerned, we can work with a single global
> registration.  However we would like to have the same interface across
> different archs.
> 
> With the new re-factoring (v7), Arun has killed most of the list
> traversal and linking between various cpu's cpuidle_driver structures.
> Now we have a per-cpu stack of registered devices and we lookup the
> structs using online cpumasks.  The cpuidle_driver structure has list
> of idle routing pointers (struct cpuidle_state) and rest of it is
> statistics that needs to be maintained at a per-cpu level anyway.  All
> that is duplicated here is the array of idle routines (struct
> cpuidle_state) on each cpu.
> 
> The objective of the refactoring is to have a single common idle
> routine management framework (remove pm_idle) and we have it done
> through cpuidle registration framework.  We can incrementally remove
> the per-cpu registration later easily by splitting the cpuidle_driver
> structure.
>

Yes, incremental refactoring makes the most sense from the do not
break as you refactor point of view.

-- 
	Balbir

Re: [v7 PATCH 0/7]: cpuidle/x86/POWER: Cleanup idle power management code in x86, cleanup drivers/cpuidle/cpuidle.c and introduce cpuidle to POWER.

[Peter Zijlstra]

On Wed, 2009-10-07 at 17:17 +0530, Balbir Singh wrote:

> > The objective of the refactoring is to have a single common idle
> > routine management framework (remove pm_idle) and we have it done
> > through cpuidle registration framework.  We can incrementally remove
> > the per-cpu registration later easily by splitting the cpuidle_driver
> > structure.
> >
> 
> Yes, incremental refactoring makes the most sense from the do not
> break as you refactor point of view.

Sure,.. but I would have though getting rid of the per-cpu-ish-ness
would have made the latter patches in this series easier. But maybe I'm
lazy ;-)

Let me go over the patches one more time, but they do look ok.

Re: [v7 PATCH 0/7]: cpuidle/x86/POWER: Cleanup idle power management code in x86, cleanup drivers/cpuidle/cpuidle.c and introduce cpuidle to POWER.

[Peter Zijlstra]

On Wed, 2009-10-07 at 16:56 +0530, Vaidyanathan Srinivasan wrote:
> * Peter Zijlstra <a.p.zijlstra@chello.nl> [2009-10-06 20:04:39]:
> 
> > On Tue, 2009-10-06 at 22:05 +0530, Arun R Bharadwaj wrote:
> > 
> > > Also, the per-cpu nature of registration/unregistration of cpuidle
> > > has been maintained as ACPI needs this.
> > 
> > Right, so can't we ditch that and have acpi default to the lowest
> common
> > C-state and warn when various cpus report different C-states?
> 
> Hi Peter,
> 
> As Arjan mentioned previously, the per-cpu registration has to stay
> for x86 for now due to legacy ACPI compatibility.  Breaking that may
> break lot of existing users and we do not have a clean fallback
> method.  

>From what I understood some broken ass bioses report different C state
availability on different CPUs in the same SMP system.

I'm suggesting to work around that by limiting all CPUs to the subset of
C states reported on all CPUs, instead of the current mess.

I haven't heard anybody tell me why that wouldn't be possible on x86