[PATCH] PM_QOS 1 of 2

[PATCH] PM_QOS 1 of 2

[Mark Gross]

The following is the cleaned up patch implementing the power management
quality of service infrastructure discussed at the pm summit last June.

It is a genralization of the latency code put into the kernel last year
by Arjan.

I would like to get this code included in the MM tree and to get some
milage on it.

One thing to note about this implementation is that it exposes an
interface to user space for registering pm_qos constraints in addition
to the kernel exports.  Its a file based interface where a module can
register a constraint and the constraint is valid only as long as the
device node is held open.  Upon closing of the device node that
constraint is cleaned up.

The patch set is in two postings.  
1) the base parameter code (this email)
2) replacing of latency.c/latenc.h with pm_qos_params.c/pm_qos_params.h


thanks,

--mgross


Signed-off-by: mark gross <mgross@linux.intel.com>

-----------

diff -urN -X linux-2.6.23-rc8/Documentation/dontdiff linux-2.6.23-rc8/include/linux/pm_qos_params.h linux-2.6.23-rc8-qos/include/linux/pm_qos_params.h
--- linux-2.6.23-rc8/include/linux/pm_qos_params.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.23-rc8-qos/include/linux/pm_qos_params.h	2007-10-01 11:19:13.000000000 -0700
@@ -0,0 +1,35 @@
+/* interface for the pm_qos_power infrastructure of the linux kernel.
+ *
+ * Mark Gross
+ */
+#include <linux/list.h>
+#include <linux/notifier.h>
+#include <linux/miscdevice.h>
+
+struct requirement_list {
+	struct list_head list;
+	union {
+		s32 value;
+		s32 usec;
+		s32 kbps;
+	};
+	char *name;
+};
+
+#define PM_QOS_RESERVED 0
+#define PM_QOS_CPU_DMA_LATENCY 1
+#define PM_QOS_NETWORK_LATENCY 2
+#define PM_QOS_NETWORK_THROUGHPUT 3
+
+#define PM_QOS_NUM_CLASSES 4
+#define PM_QOS_DEFAULT_VALUE -1
+
+int pm_qos_add_requirement(int qos, char *name, s32 value);
+int pm_qos_update_requirement(int qos, char *name, s32 new_value);
+void pm_qos_remove_requirement(int qos, char *name);
+
+int pm_qos_requirement(int qos);
+
+int pm_qos_add_notifier(int qos, struct notifier_block *notifier);
+int pm_qos_remove_notifier(int qos, struct notifier_block *notifier);
+
diff -urN -X linux-2.6.23-rc8/Documentation/dontdiff linux-2.6.23-rc8/kernel/Makefile linux-2.6.23-rc8-qos/kernel/Makefile
--- linux-2.6.23-rc8/kernel/Makefile	2007-09-26 13:54:54.000000000 -0700
+++ linux-2.6.23-rc8-qos/kernel/Makefile	2007-10-01 11:13:35.000000000 -0700
@@ -9,7 +9,7 @@
 	    rcupdate.o extable.o params.o posix-timers.o \
 	    kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \
 	    hrtimer.o rwsem.o latency.o nsproxy.o srcu.o die_notifier.o \
-	    utsname.o
+	    utsname.o pm_qos_params.o
 
 obj-$(CONFIG_STACKTRACE) += stacktrace.o
 obj-y += time/
diff -urN -X linux-2.6.23-rc8/Documentation/dontdiff linux-2.6.23-rc8/kernel/pm_qos_params.c linux-2.6.23-rc8-qos/kernel/pm_qos_params.c
--- linux-2.6.23-rc8/kernel/pm_qos_params.c	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.23-rc8-qos/kernel/pm_qos_params.c	2007-10-01 16:03:31.000000000 -0700
@@ -0,0 +1,417 @@
+/*
+ * This module exposes the interface to kernel space for specifying
+ * QoS dependencies.  It provides infrastructure for registration of:
+ *
+ * Dependents on a QoS value : register requirements
+ * Watchers of QoS value : get notified when target QoS value changes
+ *
+ * This QoS design is best effort based.  Dependents register their QoS needs.
+ * Watchers register to keep track of the current QoS needs of the system.
+ *
+ * There are 3 basic classes of QoS parameter: latency, timeout, throughput
+ * each have defined units:
+ * latency: usec
+ * timeout: usec <-- currently not used.
+ * throughput: kbs (kilo byte / sec)
+ *
+ * There are lists of pm_qos_objects each one wrapping requirements, notifiers
+ *
+ * User mode requirements on a QOS parameter register themselves to the
+ * subsystem by opening the device node /dev/... and writing there request to
+ * the node.  As long as the process holds a file handle open to the node the
+ * client continues to be accounted for.  Upon file release the usermode
+ * requirement is removed and a new qos target is computed.  This way when the
+ * requirement that the application has is cleaned up when closes the file
+ * pointer or exits the pm_qos_object will get an opportunity to clean up.
+ *
+ * mark gross mgross@linux.intel.com
+ */
+
+#include <linux/pm_qos_params.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/device.h>
+#include <linux/miscdevice.h>
+#include <linux/string.h>
+#include <linux/platform_device.h>
+#include <linux/init.h>
+
+#include <linux/uaccess.h>
+
+/*
+ * locking rule: all changes to target_value or requirements or notifiers lists
+ * or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock
+ * held, taken with _irqsave.  One lock to rule them all
+ */
+
+struct pm_qos_object {
+	struct requirement_list requirements;
+	struct srcu_notifier_head notifiers;
+	struct miscdevice pm_qos_power_miscdev;
+	char *name;
+	s32 default_value;
+	s32 target_value;
+	s32 (*comparitor)(s32, s32);
+};
+static struct pm_qos_object pm_qos_array[PM_QOS_NUM_CLASSES];
+static DEFINE_SPINLOCK(pm_qos_lock);
+
+static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
+		size_t count, loff_t *f_pos);
+static int pm_qos_power_open(struct inode *inode, struct file *filp);
+static int pm_qos_power_release(struct inode *inode, struct file *filp);
+
+static const struct file_operations pm_qos_power_fops = {
+	.write = pm_qos_power_write,
+	.open = pm_qos_power_open,
+	.release = pm_qos_power_release,
+};
+
+/* static helper functions */
+static s32 max_compare(s32 v1, s32 v2)
+{
+	return max(v1, v2);
+}
+
+static s32 min_compare(s32 v1, s32 v2)
+{
+	return min(v1, v2);
+}
+
+/* assumes pm_qos_lock is held */
+static void update_target(int target)
+{
+	s32 extreme_value;
+	struct requirement_list *node;
+
+	extreme_value = pm_qos_array[target].default_value;
+	list_for_each_entry(node,
+			&pm_qos_array[target].requirements.list, list) {
+		extreme_value = pm_qos_array[target].comparitor(
+				extreme_value, node->value);
+	}
+	if (pm_qos_array[target].target_value != extreme_value) {
+		pm_qos_array[target].target_value = extreme_value;
+		pr_debug(KERN_ERR "new target for qos %d is %d\n", target,
+			pm_qos_array[target].target_value);
+		srcu_notifier_call_chain(&pm_qos_array[target].notifiers,
+			(unsigned long) pm_qos_array[target].target_value,
+						NULL);
+	}
+}
+
+static int register_new_pm_qos_misc(struct pm_qos_object *qos)
+{
+	qos->pm_qos_power_miscdev.minor = MISC_DYNAMIC_MINOR;
+	qos->pm_qos_power_miscdev.name = qos->name;
+	qos->pm_qos_power_miscdev.fops = &pm_qos_power_fops;
+
+	return misc_register(&qos->pm_qos_power_miscdev);
+}
+
+
+/* constructors */
+static int init_pm_qos_object(int pm_qos_class, const char *name,
+			s32 default_value, s32 (*comparitor)(s32, s32))
+{
+	int ret = -ENOMEM;
+	struct pm_qos_object *qos = NULL;
+
+	if (pm_qos_class < PM_QOS_NUM_CLASSES) {
+		qos = &pm_qos_array[pm_qos_class];
+		qos->name = kstrdup(name, GFP_KERNEL);
+		if (!qos->name)
+			goto cleanup;
+
+		qos->default_value = default_value;
+		qos->target_value = default_value;
+		qos->comparitor = comparitor;
+		srcu_init_notifier_head(&qos->notifiers);
+		INIT_LIST_HEAD(&qos->requirements.list);
+		ret = register_new_pm_qos_misc(qos);
+		if (ret < 0)
+			goto cleanup;
+	} else
+		ret = -EINVAL;
+
+	return ret;
+cleanup:
+	kfree(qos->name);
+
+	return ret;
+}
+
+static int find_pm_qos_object_by_minor(int minor)
+{
+	int pm_qos_class;
+
+	for (pm_qos_class = 0;
+		pm_qos_class < PM_QOS_NUM_CLASSES; pm_qos_class++) {
+		if (minor ==
+			pm_qos_array[pm_qos_class].pm_qos_power_miscdev.minor)
+			return pm_qos_class;
+	}
+	return -1;
+}
+
+static int new_latency_qos(int pm_qos_class, const char *name)
+{
+	return init_pm_qos_object(pm_qos_class, name, 2000 * USEC_PER_SEC,
+			min_compare);
+	/* 2000 sec is about infinite */
+}
+
+static int new_throughput_qos(int pm_qos_class, const char *name)
+{
+	return init_pm_qos_object(pm_qos_class, name, 0, max_compare);
+}
+
+/**
+ * pm_qos_requirement - returns current system wide qos expectation
+ * @pm_qos_class: identification of which qos value is requested
+ *
+ * This function returns the current target value in an atomic manner.
+ */
+int pm_qos_requirement(int pm_qos_class)
+{
+	int ret_val;
+	unsigned long flags;
+
+	spin_lock_irqsave(&pm_qos_lock, flags);
+	ret_val = pm_qos_array[pm_qos_class].target_value;
+	spin_unlock_irqrestore(&pm_qos_lock, flags);
+
+	return ret_val;
+}
+EXPORT_SYMBOL_GPL(pm_qos_requirement);
+
+/**
+ * pm_qos_add_requirement - inserts new qos request into the list
+ * @pm_qos_class: identifies which list of qos request to us
+ * @name: identifies the request
+ * @value: defines the qos request
+ *
+ * This function inserts a new entry in the pm_qos_class list of requested qos
+ * performance charactoistics.  It recomputes the agregate QoS expectations for
+ * the pm_qos_class of parrameters.
+ */
+int pm_qos_add_requirement(int pm_qos_class, char *name, s32 value)
+{
+	struct requirement_list *dep;
+	unsigned long flags;
+
+	dep = kzalloc(sizeof(struct requirement_list), GFP_KERNEL);
+	if (dep) {
+		if (value == PM_QOS_DEFAULT_VALUE)
+			dep->value = pm_qos_array[pm_qos_class].default_value;
+		else
+			dep->value = value;
+		dep->name = kstrdup(name, GFP_KERNEL);
+		if (!dep->name)
+			goto cleanup;
+
+		spin_lock_irqsave(&pm_qos_lock, flags);
+		list_add(&dep->list,
+			&pm_qos_array[pm_qos_class].requirements.list);
+		update_target(pm_qos_class);
+		spin_unlock_irqrestore(&pm_qos_lock, flags);
+
+		return 0;
+	}
+
+cleanup:
+	kfree(dep);
+	return -ENOMEM;
+}
+EXPORT_SYMBOL_GPL(pm_qos_add_requirement);
+
+/**
+ * pm_qos_update_requirement - modifies an existing qos request
+ * @pm_qos_class: identifies which list of qos request to us
+ * @name: identifies the request
+ * @value: defines the qos request
+ *
+ * Updates an existing qos requierement for the pm_qos_class of parameters along
+ * with updating the target pm_qos_class value.
+ *
+ * If the named request isn't in the lest then no change is made.
+ */
+int pm_qos_update_requirement(int pm_qos_class, char *name, s32 new_value)
+{
+	unsigned long flags;
+	struct requirement_list *node;
+	int pending_update = 0;
+
+	spin_lock_irqsave(&pm_qos_lock, flags);
+	list_for_each_entry(node,
+		&pm_qos_array[pm_qos_class].requirements.list, list) {
+		if (strcmp(node->name, name) == 0) {
+			if (new_value == PM_QOS_DEFAULT_VALUE)
+				node->value =
+				pm_qos_array[pm_qos_class].default_value;
+			else
+				node->value = new_value;
+			pending_update = 1;
+			break;
+		}
+	}
+	if (pending_update)
+		update_target(pm_qos_class);
+
+	spin_unlock_irqrestore(&pm_qos_lock, flags);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pm_qos_update_requirement);
+
+/**
+ * pm_qos_remove_requirement - modifies an existing qos request
+ * @pm_qos_class: identifies which list of qos request to us
+ * @name: identifies the request
+ *
+ * Will remove named qos request from pm_qos_class list of parrameters and
+ * recompute the current target value for the pm_qos_class.
+ */
+void pm_qos_remove_requirement(int pm_qos_class, char *name)
+{
+	unsigned long flags;
+	struct requirement_list *node;
+	int pending_update = 0;
+
+	spin_lock_irqsave(&pm_qos_lock, flags);
+	list_for_each_entry(node,
+		&pm_qos_array[pm_qos_class].requirements.list, list) {
+		if (strcmp(node->name, name) == 0) {
+			kfree(node->name);
+			list_del(&node->list);
+			kfree(node);
+			pending_update = 1;
+			break;
+		}
+	}
+	if (pending_update)
+		update_target(pm_qos_class);
+	spin_unlock_irqrestore(&pm_qos_lock, flags);
+}
+EXPORT_SYMBOL_GPL(pm_qos_remove_requirement);
+
+/**
+ * pm_qos_add_notifier - sets notification entry for changes to target value
+ * @pm_qos_class: identifies which qos target changes should be notified.
+ * @notifier: notifier block managed by caller.
+ *
+ * will register the notifier into a notification chain that gets called
+ * uppon changes to the pm_qos_class target value.
+ */
+ int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
+{
+	unsigned long flags;
+	int retval;
+
+	spin_lock_irqsave(&pm_qos_lock, flags);
+	retval = srcu_notifier_chain_register(
+			&pm_qos_array[pm_qos_class].notifiers, notifier);
+	spin_unlock_irqrestore(&pm_qos_lock, flags);
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(pm_qos_add_notifier);
+
+/**
+ * pm_qos_remove_notifier - deletes notification entry from chain.
+ * @pm_qos_class: identifies which qos target changes are notified.
+ * @notifier: notifier block to be removed.
+ *
+ * will remove the notifier from the notification chain that gets called
+ * uppon changes to the pm_qos_class target value.
+ */
+int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
+{
+	unsigned long flags;
+	int retval;
+
+	spin_lock_irqsave(&pm_qos_lock, flags);
+	retval = srcu_notifier_chain_unregister(
+			&pm_qos_array[pm_qos_class].notifiers, notifier);
+	spin_unlock_irqrestore(&pm_qos_lock, flags);
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);
+
+#define PID_NAME_LEN sizeof("process_1234567890")
+static char name[PID_NAME_LEN];
+
+static int pm_qos_power_open(struct inode *inode, struct file *filp)
+{
+	int ret;
+	int pm_qos_class;
+
+	pm_qos_class = find_pm_qos_object_by_minor(iminor(inode));
+	if (pm_qos_class >= 0) {
+		filp->private_data = (void *) pm_qos_class;
+		sprintf(name, "process_%d", current->pid);
+		ret = pm_qos_add_requirement(pm_qos_class, name,
+					PM_QOS_DEFAULT_VALUE);
+		if (ret >= 0)
+			return 0;
+	}
+
+	return -EPERM;
+}
+
+static int pm_qos_power_release(struct inode *inode, struct file *filp)
+{
+	int pm_qos_class;
+
+	pm_qos_class = (int) filp->private_data;
+	sprintf(name, "process_%d", current->pid);
+	pm_qos_remove_requirement(pm_qos_class, name);
+
+	return 0;
+}
+
+static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
+		size_t count, loff_t *f_pos)
+{
+	s32 value;
+	int pm_qos_class;
+
+	pm_qos_class = (int) filp->private_data;
+	if (count != sizeof(s32))
+		return -EINVAL;
+	if (copy_from_user(&value, buf, sizeof(s32)))
+		return -EFAULT;
+	sprintf(name, "process_%d", current->pid);
+	pm_qos_update_requirement(pm_qos_class, name, value);
+
+	return  sizeof(s32);
+}
+
+
+static int __init pm_qos_power_init(void)
+{
+	int ret = 0;
+	ret = new_latency_qos(PM_QOS_CPU_DMA_LATENCY, "cpu_dma_latency");
+	if (ret < 0) {
+		printk(KERN_ERR "pm_qos_param: cpu_dma_latency setup failed\n");
+		return ret;
+	}
+	ret = new_latency_qos(PM_QOS_NETWORK_LATENCY, "network_latency");
+	if (ret < 0) {
+		printk(KERN_ERR "pm_qos_param: network_latency setup failed\n");
+		return ret;
+	}
+	ret = new_throughput_qos(PM_QOS_NETWORK_THROUGHPUT,
+			"network_throughput");
+	if (ret < 0)
+		printk(KERN_ERR
+			"pm_qos_param: network_throughput setup failed\n");
+
+	return ret;
+}
+
+late_initcall(pm_qos_power_init);

[PATCH] PM_QOS 1 of 2

[Mark Gross]

The following is the cleaned up patch implementing the power management
quality of service infrastructure discussed at the pm summit last June.

It is a genralization of the latency code put into the kernel last year
by Arjan.

I would like to get this code included in the MM tree and to get some
milage on it.

One thing to note about this implementation is that it exposes an
interface to user space for registering pm_qos constraints in addition
to the kernel exports.  Its a file based interface where a module can
register a constraint and the constraint is valid only as long as the
device node is held open.  Upon closing of the device node that
constraint is cleaned up.

The patch set is in two postings.  
1) the base parameter code (this email)
2) replacing of latency.c/latenc.h with pm_qos_params.c/pm_qos_params.h


thanks,

--mgross


Signed-off-by: mark gross <mgross@linux.intel.com>

-----------

diff -urN -X linux-2.6.23-rc8/Documentation/dontdiff linux-2.6.23-rc8/include/linux/pm_qos_params.h linux-2.6.23-rc8-qos/include/linux/pm_qos_params.h
--- linux-2.6.23-rc8/include/linux/pm_qos_params.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.23-rc8-qos/include/linux/pm_qos_params.h	2007-10-01 11:19:13.000000000 -0700
@@ -0,0 +1,35 @@
+/* interface for the pm_qos_power infrastructure of the linux kernel.
+ *
+ * Mark Gross
+ */
+#include <linux/list.h>
+#include <linux/notifier.h>
+#include <linux/miscdevice.h>
+
+struct requirement_list {
+	struct list_head list;
+	union {
+		s32 value;
+		s32 usec;
+		s32 kbps;
+	};
+	char *name;
+};
+
+#define PM_QOS_RESERVED 0
+#define PM_QOS_CPU_DMA_LATENCY 1
+#define PM_QOS_NETWORK_LATENCY 2
+#define PM_QOS_NETWORK_THROUGHPUT 3
+
+#define PM_QOS_NUM_CLASSES 4
+#define PM_QOS_DEFAULT_VALUE -1
+
+int pm_qos_add_requirement(int qos, char *name, s32 value);
+int pm_qos_update_requirement(int qos, char *name, s32 new_value);
+void pm_qos_remove_requirement(int qos, char *name);
+
+int pm_qos_requirement(int qos);
+
+int pm_qos_add_notifier(int qos, struct notifier_block *notifier);
+int pm_qos_remove_notifier(int qos, struct notifier_block *notifier);
+
diff -urN -X linux-2.6.23-rc8/Documentation/dontdiff linux-2.6.23-rc8/kernel/Makefile linux-2.6.23-rc8-qos/kernel/Makefile
--- linux-2.6.23-rc8/kernel/Makefile	2007-09-26 13:54:54.000000000 -0700
+++ linux-2.6.23-rc8-qos/kernel/Makefile	2007-10-01 11:13:35.000000000 -0700
@@ -9,7 +9,7 @@
 	    rcupdate.o extable.o params.o posix-timers.o \
 	    kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \
 	    hrtimer.o rwsem.o latency.o nsproxy.o srcu.o die_notifier.o \
-	    utsname.o
+	    utsname.o pm_qos_params.o
 
 obj-$(CONFIG_STACKTRACE) += stacktrace.o
 obj-y += time/
diff -urN -X linux-2.6.23-rc8/Documentation/dontdiff linux-2.6.23-rc8/kernel/pm_qos_params.c linux-2.6.23-rc8-qos/kernel/pm_qos_params.c
--- linux-2.6.23-rc8/kernel/pm_qos_params.c	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.23-rc8-qos/kernel/pm_qos_params.c	2007-10-01 16:03:31.000000000 -0700
@@ -0,0 +1,417 @@
+/*
+ * This module exposes the interface to kernel space for specifying
+ * QoS dependencies.  It provides infrastructure for registration of:
+ *
+ * Dependents on a QoS value : register requirements
+ * Watchers of QoS value : get notified when target QoS value changes
+ *
+ * This QoS design is best effort based.  Dependents register their QoS needs.
+ * Watchers register to keep track of the current QoS needs of the system.
+ *
+ * There are 3 basic classes of QoS parameter: latency, timeout, throughput
+ * each have defined units:
+ * latency: usec
+ * timeout: usec <-- currently not used.
+ * throughput: kbs (kilo byte / sec)
+ *
+ * There are lists of pm_qos_objects each one wrapping requirements, notifiers
+ *
+ * User mode requirements on a QOS parameter register themselves to the
+ * subsystem by opening the device node /dev/... and writing there request to
+ * the node.  As long as the process holds a file handle open to the node the
+ * client continues to be accounted for.  Upon file release the usermode
+ * requirement is removed and a new qos target is computed.  This way when the
+ * requirement that the application has is cleaned up when closes the file
+ * pointer or exits the pm_qos_object will get an opportunity to clean up.
+ *
+ * mark gross mgross@linux.intel.com
+ */
+
+#include <linux/pm_qos_params.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/device.h>
+#include <linux/miscdevice.h>
+#include <linux/string.h>
+#include <linux/platform_device.h>
+#include <linux/init.h>
+
+#include <linux/uaccess.h>
+
+/*
+ * locking rule: all changes to target_value or requirements or notifiers lists
+ * or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock
+ * held, taken with _irqsave.  One lock to rule them all
+ */
+
+struct pm_qos_object {
+	struct requirement_list requirements;
+	struct srcu_notifier_head notifiers;
+	struct miscdevice pm_qos_power_miscdev;
+	char *name;
+	s32 default_value;
+	s32 target_value;
+	s32 (*comparitor)(s32, s32);
+};
+static struct pm_qos_object pm_qos_array[PM_QOS_NUM_CLASSES];
+static DEFINE_SPINLOCK(pm_qos_lock);
+
+static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
+		size_t count, loff_t *f_pos);
+static int pm_qos_power_open(struct inode *inode, struct file *filp);
+static int pm_qos_power_release(struct inode *inode, struct file *filp);
+
+static const struct file_operations pm_qos_power_fops = {
+	.write = pm_qos_power_write,
+	.open = pm_qos_power_open,
+	.release = pm_qos_power_release,
+};
+
+/* static helper functions */
+static s32 max_compare(s32 v1, s32 v2)
+{
+	return max(v1, v2);
+}
+
+static s32 min_compare(s32 v1, s32 v2)
+{
+	return min(v1, v2);
+}
+
+/* assumes pm_qos_lock is held */
+static void update_target(int target)
+{
+	s32 extreme_value;
+	struct requirement_list *node;
+
+	extreme_value = pm_qos_array[target].default_value;
+	list_for_each_entry(node,
+			&pm_qos_array[target].requirements.list, list) {
+		extreme_value = pm_qos_array[target].comparitor(
+				extreme_value, node->value);
+	}
+	if (pm_qos_array[target].target_value != extreme_value) {
+		pm_qos_array[target].target_value = extreme_value;
+		pr_debug(KERN_ERR "new target for qos %d is %d\n", target,
+			pm_qos_array[target].target_value);
+		srcu_notifier_call_chain(&pm_qos_array[target].notifiers,
+			(unsigned long) pm_qos_array[target].target_value,
+						NULL);
+	}
+}
+
+static int register_new_pm_qos_misc(struct pm_qos_object *qos)
+{
+	qos->pm_qos_power_miscdev.minor = MISC_DYNAMIC_MINOR;
+	qos->pm_qos_power_miscdev.name = qos->name;
+	qos->pm_qos_power_miscdev.fops = &pm_qos_power_fops;
+
+	return misc_register(&qos->pm_qos_power_miscdev);
+}
+
+
+/* constructors */
+static int init_pm_qos_object(int pm_qos_class, const char *name,
+			s32 default_value, s32 (*comparitor)(s32, s32))
+{
+	int ret = -ENOMEM;
+	struct pm_qos_object *qos = NULL;
+
+	if (pm_qos_class < PM_QOS_NUM_CLASSES) {
+		qos = &pm_qos_array[pm_qos_class];
+		qos->name = kstrdup(name, GFP_KERNEL);
+		if (!qos->name)
+			goto cleanup;
+
+		qos->default_value = default_value;
+		qos->target_value = default_value;
+		qos->comparitor = comparitor;
+		srcu_init_notifier_head(&qos->notifiers);
+		INIT_LIST_HEAD(&qos->requirements.list);
+		ret = register_new_pm_qos_misc(qos);
+		if (ret < 0)
+			goto cleanup;
+	} else
+		ret = -EINVAL;
+
+	return ret;
+cleanup:
+	kfree(qos->name);
+
+	return ret;
+}
+
+static int find_pm_qos_object_by_minor(int minor)
+{
+	int pm_qos_class;
+
+	for (pm_qos_class = 0;
+		pm_qos_class < PM_QOS_NUM_CLASSES; pm_qos_class++) {
+		if (minor ==
+			pm_qos_array[pm_qos_class].pm_qos_power_miscdev.minor)
+			return pm_qos_class;
+	}
+	return -1;
+}
+
+static int new_latency_qos(int pm_qos_class, const char *name)
+{
+	return init_pm_qos_object(pm_qos_class, name, 2000 * USEC_PER_SEC,
+			min_compare);
+	/* 2000 sec is about infinite */
+}
+
+static int new_throughput_qos(int pm_qos_class, const char *name)
+{
+	return init_pm_qos_object(pm_qos_class, name, 0, max_compare);
+}
+
+/**
+ * pm_qos_requirement - returns current system wide qos expectation
+ * @pm_qos_class: identification of which qos value is requested
+ *
+ * This function returns the current target value in an atomic manner.
+ */
+int pm_qos_requirement(int pm_qos_class)
+{
+	int ret_val;
+	unsigned long flags;
+
+	spin_lock_irqsave(&pm_qos_lock, flags);
+	ret_val = pm_qos_array[pm_qos_class].target_value;
+	spin_unlock_irqrestore(&pm_qos_lock, flags);
+
+	return ret_val;
+}
+EXPORT_SYMBOL_GPL(pm_qos_requirement);
+
+/**
+ * pm_qos_add_requirement - inserts new qos request into the list
+ * @pm_qos_class: identifies which list of qos request to us
+ * @name: identifies the request
+ * @value: defines the qos request
+ *
+ * This function inserts a new entry in the pm_qos_class list of requested qos
+ * performance charactoistics.  It recomputes the agregate QoS expectations for
+ * the pm_qos_class of parrameters.
+ */
+int pm_qos_add_requirement(int pm_qos_class, char *name, s32 value)
+{
+	struct requirement_list *dep;
+	unsigned long flags;
+
+	dep = kzalloc(sizeof(struct requirement_list), GFP_KERNEL);
+	if (dep) {
+		if (value == PM_QOS_DEFAULT_VALUE)
+			dep->value = pm_qos_array[pm_qos_class].default_value;
+		else
+			dep->value = value;
+		dep->name = kstrdup(name, GFP_KERNEL);
+		if (!dep->name)
+			goto cleanup;
+
+		spin_lock_irqsave(&pm_qos_lock, flags);
+		list_add(&dep->list,
+			&pm_qos_array[pm_qos_class].requirements.list);
+		update_target(pm_qos_class);
+		spin_unlock_irqrestore(&pm_qos_lock, flags);
+
+		return 0;
+	}
+
+cleanup:
+	kfree(dep);
+	return -ENOMEM;
+}
+EXPORT_SYMBOL_GPL(pm_qos_add_requirement);
+
+/**
+ * pm_qos_update_requirement - modifies an existing qos request
+ * @pm_qos_class: identifies which list of qos request to us
+ * @name: identifies the request
+ * @value: defines the qos request
+ *
+ * Updates an existing qos requierement for the pm_qos_class of parameters along
+ * with updating the target pm_qos_class value.
+ *
+ * If the named request isn't in the lest then no change is made.
+ */
+int pm_qos_update_requirement(int pm_qos_class, char *name, s32 new_value)
+{
+	unsigned long flags;
+	struct requirement_list *node;
+	int pending_update = 0;
+
+	spin_lock_irqsave(&pm_qos_lock, flags);
+	list_for_each_entry(node,
+		&pm_qos_array[pm_qos_class].requirements.list, list) {
+		if (strcmp(node->name, name) == 0) {
+			if (new_value == PM_QOS_DEFAULT_VALUE)
+				node->value =
+				pm_qos_array[pm_qos_class].default_value;
+			else
+				node->value = new_value;
+			pending_update = 1;
+			break;
+		}
+	}
+	if (pending_update)
+		update_target(pm_qos_class);
+
+	spin_unlock_irqrestore(&pm_qos_lock, flags);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pm_qos_update_requirement);
+
+/**
+ * pm_qos_remove_requirement - modifies an existing qos request
+ * @pm_qos_class: identifies which list of qos request to us
+ * @name: identifies the request
+ *
+ * Will remove named qos request from pm_qos_class list of parrameters and
+ * recompute the current target value for the pm_qos_class.
+ */
+void pm_qos_remove_requirement(int pm_qos_class, char *name)
+{
+	unsigned long flags;
+	struct requirement_list *node;
+	int pending_update = 0;
+
+	spin_lock_irqsave(&pm_qos_lock, flags);
+	list_for_each_entry(node,
+		&pm_qos_array[pm_qos_class].requirements.list, list) {
+		if (strcmp(node->name, name) == 0) {
+			kfree(node->name);
+			list_del(&node->list);
+			kfree(node);
+			pending_update = 1;
+			break;
+		}
+	}
+	if (pending_update)
+		update_target(pm_qos_class);
+	spin_unlock_irqrestore(&pm_qos_lock, flags);
+}
+EXPORT_SYMBOL_GPL(pm_qos_remove_requirement);
+
+/**
+ * pm_qos_add_notifier - sets notification entry for changes to target value
+ * @pm_qos_class: identifies which qos target changes should be notified.
+ * @notifier: notifier block managed by caller.
+ *
+ * will register the notifier into a notification chain that gets called
+ * uppon changes to the pm_qos_class target value.
+ */
+ int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
+{
+	unsigned long flags;
+	int retval;
+
+	spin_lock_irqsave(&pm_qos_lock, flags);
+	retval = srcu_notifier_chain_register(
+			&pm_qos_array[pm_qos_class].notifiers, notifier);
+	spin_unlock_irqrestore(&pm_qos_lock, flags);
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(pm_qos_add_notifier);
+
+/**
+ * pm_qos_remove_notifier - deletes notification entry from chain.
+ * @pm_qos_class: identifies which qos target changes are notified.
+ * @notifier: notifier block to be removed.
+ *
+ * will remove the notifier from the notification chain that gets called
+ * uppon changes to the pm_qos_class target value.
+ */
+int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
+{
+	unsigned long flags;
+	int retval;
+
+	spin_lock_irqsave(&pm_qos_lock, flags);
+	retval = srcu_notifier_chain_unregister(
+			&pm_qos_array[pm_qos_class].notifiers, notifier);
+	spin_unlock_irqrestore(&pm_qos_lock, flags);
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);
+
+#define PID_NAME_LEN sizeof("process_1234567890")
+static char name[PID_NAME_LEN];
+
+static int pm_qos_power_open(struct inode *inode, struct file *filp)
+{
+	int ret;
+	int pm_qos_class;
+
+	pm_qos_class = find_pm_qos_object_by_minor(iminor(inode));
+	if (pm_qos_class >= 0) {
+		filp->private_data = (void *) pm_qos_class;
+		sprintf(name, "process_%d", current->pid);
+		ret = pm_qos_add_requirement(pm_qos_class, name,
+					PM_QOS_DEFAULT_VALUE);
+		if (ret >= 0)
+			return 0;
+	}
+
+	return -EPERM;
+}
+
+static int pm_qos_power_release(struct inode *inode, struct file *filp)
+{
+	int pm_qos_class;
+
+	pm_qos_class = (int) filp->private_data;
+	sprintf(name, "process_%d", current->pid);
+	pm_qos_remove_requirement(pm_qos_class, name);
+
+	return 0;
+}
+
+static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
+		size_t count, loff_t *f_pos)
+{
+	s32 value;
+	int pm_qos_class;
+
+	pm_qos_class = (int) filp->private_data;
+	if (count != sizeof(s32))
+		return -EINVAL;
+	if (copy_from_user(&value, buf, sizeof(s32)))
+		return -EFAULT;
+	sprintf(name, "process_%d", current->pid);
+	pm_qos_update_requirement(pm_qos_class, name, value);
+
+	return  sizeof(s32);
+}
+
+
+static int __init pm_qos_power_init(void)
+{
+	int ret = 0;
+	ret = new_latency_qos(PM_QOS_CPU_DMA_LATENCY, "cpu_dma_latency");
+	if (ret < 0) {
+		printk(KERN_ERR "pm_qos_param: cpu_dma_latency setup failed\n");
+		return ret;
+	}
+	ret = new_latency_qos(PM_QOS_NETWORK_LATENCY, "network_latency");
+	if (ret < 0) {
+		printk(KERN_ERR "pm_qos_param: network_latency setup failed\n");
+		return ret;
+	}
+	ret = new_throughput_qos(PM_QOS_NETWORK_THROUGHPUT,
+			"network_throughput");
+	if (ret < 0)
+		printk(KERN_ERR
+			"pm_qos_param: network_throughput setup failed\n");
+
+	return ret;
+}
+
+late_initcall(pm_qos_power_init);

Re: [linux-pm] [PATCH] PM_QOS 2 of 2

[Mark Gross]

this is the second part of the patch to replace latency.c use with
pm_qos_params use.


--mgross



Signed-off-by: mark gross <mgross@linux.intel.com>

-----------

diff -urN -X linux-2.6.23-rc8/Documentation/dontdiff linux-2.6.23-rc8-qos/drivers/acpi/processor_idle.c linux-2.6.23-rc8-qos-nolatency.c/drivers/acpi/processor_idle.c
--- linux-2.6.23-rc8-qos/drivers/acpi/processor_idle.c	2007-09-26 13:54:28.000000000 -0700
+++ linux-2.6.23-rc8-qos-nolatency.c/drivers/acpi/processor_idle.c	2007-10-01 11:32:13.000000000 -0700
@@ -38,7 +38,7 @@
 #include <linux/dmi.h>
 #include <linux/moduleparam.h>
 #include <linux/sched.h>	/* need_resched() */
-#include <linux/latency.h>
+#include <linux/pm_qos_params.h>
 #include <linux/clockchips.h>
 
 /*
@@ -605,7 +605,8 @@
 	if (cx->promotion.state &&
 	    ((cx->promotion.state - pr->power.states) <= max_cstate)) {
 		if (sleep_ticks > cx->promotion.threshold.ticks &&
-		  cx->promotion.state->latency <= system_latency_constraint()) {
+		  cx->promotion.state->latency <=
+				pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY)) {
 			cx->promotion.count++;
 			cx->demotion.count = 0;
 			if (cx->promotion.count >=
@@ -649,7 +650,8 @@
 	 * or if the latency of the current state is unacceptable
 	 */
 	if ((pr->power.state - pr->power.states) > max_cstate ||
-		pr->power.state->latency > system_latency_constraint()) {
+		pr->power.state->latency >
+				pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY)) {
 		if (cx->demotion.state)
 			next_state = cx->demotion.state;
 	}
@@ -1173,7 +1175,7 @@
 		   "maximum allowed latency: %d usec\n",
 		   pr->power.state ? pr->power.state - pr->power.states : 0,
 		   max_cstate, (unsigned)pr->power.bm_activity,
-		   system_latency_constraint());
+		   pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY));
 
 	seq_puts(seq, "states:\n");
 
@@ -1280,7 +1282,8 @@
 			       max_cstate);
 		first_run++;
 #ifdef CONFIG_SMP
-		register_latency_notifier(&acpi_processor_latency_notifier);
+		pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY,
+				&acpi_processor_latency_notifier);
 #endif
 	}
 
@@ -1354,7 +1357,8 @@
 		 */
 		cpu_idle_wait();
 #ifdef CONFIG_SMP
-		unregister_latency_notifier(&acpi_processor_latency_notifier);
+		pm_qos_remove_notifier(PM_QOS_CPU_DMA_LATENCY,
+				&acpi_processor_latency_notifier);
 #endif
 	}
 
diff -urN -X linux-2.6.23-rc8/Documentation/dontdiff linux-2.6.23-rc8-qos/drivers/net/wireless/ipw2100.c linux-2.6.23-rc8-qos-nolatency.c/drivers/net/wireless/ipw2100.c
--- linux-2.6.23-rc8-qos/drivers/net/wireless/ipw2100.c	2007-09-26 13:54:34.000000000 -0700
+++ linux-2.6.23-rc8-qos-nolatency.c/drivers/net/wireless/ipw2100.c	2007-10-01 12:32:56.000000000 -0700
@@ -162,7 +162,7 @@
 #include <linux/firmware.h>
 #include <linux/acpi.h>
 #include <linux/ctype.h>
-#include <linux/latency.h>
+#include <linux/pm_qos_params.h>
 
 #include "ipw2100.h"
 
@@ -1701,7 +1701,7 @@
 	/* the ipw2100 hardware really doesn't want power management delays
 	 * longer than 175usec
 	 */
-	modify_acceptable_latency("ipw2100", 175);
+	pm_qos_update_requirement(PM_QOS_CPU_DMA_LATENCY, "ipw2100", 175);
 
 	/* If the interrupt is enabled, turn it off... */
 	spin_lock_irqsave(&priv->low_lock, flags);
@@ -1856,7 +1856,8 @@
 	ipw2100_disable_interrupts(priv);
 	spin_unlock_irqrestore(&priv->low_lock, flags);
 
-	modify_acceptable_latency("ipw2100", INFINITE_LATENCY);
+	pm_qos_update_requirement(PM_QOS_CPU_DMA_LATENCY, "ipw2100",
+			PM_QOS_DEFAULT_VALUE);
 
 #ifdef ACPI_CSTATE_LIMIT_DEFINED
 	if (priv->config & CFG_C3_DISABLED) {
@@ -6544,7 +6545,8 @@
 	if (ret)
 		goto out;
 
-	set_acceptable_latency("ipw2100", INFINITE_LATENCY);
+	pm_qos_add_requirement(PM_QOS_CPU_DMA_LATENCY, "ipw2100",
+			PM_QOS_DEFAULT_VALUE);
 #ifdef CONFIG_IPW2100_DEBUG
 	ipw2100_debug_level = debug;
 	ret = driver_create_file(&ipw2100_pci_driver.driver,
@@ -6566,7 +6568,7 @@
 			   &driver_attr_debug_level);
 #endif
 	pci_unregister_driver(&ipw2100_pci_driver);
-	remove_acceptable_latency("ipw2100");
+	pm_qos_remove_requirement(PM_QOS_CPU_DMA_LATENCY, "ipw2100");
 }
 
 module_init(ipw2100_init);
diff -urN -X linux-2.6.23-rc8/Documentation/dontdiff linux-2.6.23-rc8-qos/include/linux/latency.h linux-2.6.23-rc8-qos-nolatency.c/include/linux/latency.h
--- linux-2.6.23-rc8-qos/include/linux/latency.h	2007-07-08 16:32:17.000000000 -0700
+++ linux-2.6.23-rc8-qos-nolatency.c/include/linux/latency.h	1969-12-31 16:00:00.000000000 -0800
@@ -1,25 +0,0 @@
-/*
- * latency.h: Explicit system-wide latency-expectation infrastructure
- *
- * (C) Copyright 2006 Intel Corporation
- * Author: Arjan van de Ven <arjan@linux.intel.com>
- *
- */
-
-#ifndef _INCLUDE_GUARD_LATENCY_H_
-#define _INCLUDE_GUARD_LATENCY_H_
-
-#include <linux/notifier.h>
-
-void set_acceptable_latency(char *identifier, int usecs);
-void modify_acceptable_latency(char *identifier, int usecs);
-void remove_acceptable_latency(char *identifier);
-void synchronize_acceptable_latency(void);
-int system_latency_constraint(void);
-
-int register_latency_notifier(struct notifier_block * nb);
-int unregister_latency_notifier(struct notifier_block * nb);
-
-#define INFINITE_LATENCY 1000000
-
-#endif
diff -urN -X linux-2.6.23-rc8/Documentation/dontdiff linux-2.6.23-rc8-qos/kernel/latency.c linux-2.6.23-rc8-qos-nolatency.c/kernel/latency.c
--- linux-2.6.23-rc8-qos/kernel/latency.c	2007-07-08 16:32:17.000000000 -0700
+++ linux-2.6.23-rc8-qos-nolatency.c/kernel/latency.c	1969-12-31 16:00:00.000000000 -0800
@@ -1,280 +0,0 @@
-/*
- * latency.c: Explicit system-wide latency-expectation infrastructure
- *
- * The purpose of this infrastructure is to allow device drivers to set
- * latency constraint they have and to collect and summarize these
- * expectations globally. The cummulated result can then be used by
- * power management and similar users to make decisions that have
- * tradoffs with a latency component.
- *
- * An example user of this are the x86 C-states; each higher C state saves
- * more power, but has a higher exit latency. For the idle loop power
- * code to make a good decision which C-state to use, information about
- * acceptable latencies is required.
- *
- * An example announcer of latency is an audio driver that knowns it
- * will get an interrupt when the hardware has 200 usec of samples
- * left in the DMA buffer; in that case the driver can set a latency
- * constraint of, say, 150 usec.
- *
- * Multiple drivers can each announce their maximum accepted latency,
- * to keep these appart, a string based identifier is used.
- *
- *
- * (C) Copyright 2006 Intel Corporation
- * Author: Arjan van de Ven <arjan@linux.intel.com>
- *
- * 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; version 2
- * of the License.
- */
-
-#include <linux/latency.h>
-#include <linux/list.h>
-#include <linux/spinlock.h>
-#include <linux/slab.h>
-#include <linux/module.h>
-#include <linux/notifier.h>
-#include <linux/jiffies.h>
-#include <asm/atomic.h>
-
-struct latency_info {
-	struct list_head list;
-	int usecs;
-	char *identifier;
-};
-
-/*
- * locking rule: all modifications to current_max_latency and
- * latency_list need to be done while holding the latency_lock.
- * latency_lock needs to be taken _irqsave.
- */
-static atomic_t current_max_latency;
-static DEFINE_SPINLOCK(latency_lock);
-
-static LIST_HEAD(latency_list);
-static BLOCKING_NOTIFIER_HEAD(latency_notifier);
-
-/*
- * This function returns the maximum latency allowed, which
- * happens to be the minimum of all maximum latencies on the
- * list.
- */
-static int __find_max_latency(void)
-{
-	int min = INFINITE_LATENCY;
-	struct latency_info *info;
-
-	list_for_each_entry(info, &latency_list, list) {
-		if (info->usecs < min)
-			min = info->usecs;
-	}
-	return min;
-}
-
-/**
- * set_acceptable_latency - sets the maximum latency acceptable
- * @identifier: string that identifies this driver
- * @usecs: maximum acceptable latency for this driver
- *
- * This function informs the kernel that this device(driver)
- * can accept at most usecs latency. This setting is used for
- * power management and similar tradeoffs.
- *
- * This function sleeps and can only be called from process
- * context.
- * Calling this function with an existing identifier is valid
- * and will cause the existing latency setting to be changed.
- */
-void set_acceptable_latency(char *identifier, int usecs)
-{
-	struct latency_info *info, *iter;
-	unsigned long flags;
-	int found_old = 0;
-
-	info = kzalloc(sizeof(struct latency_info), GFP_KERNEL);
-	if (!info)
-		return;
-	info->usecs = usecs;
-	info->identifier = kstrdup(identifier, GFP_KERNEL);
-	if (!info->identifier)
-		goto free_info;
-
-	spin_lock_irqsave(&latency_lock, flags);
-	list_for_each_entry(iter, &latency_list, list) {
-		if (strcmp(iter->identifier, identifier)==0) {
-			found_old = 1;
-			iter->usecs = usecs;
-			break;
-		}
-	}
-	if (!found_old)
-		list_add(&info->list, &latency_list);
-
-	if (usecs < atomic_read(&current_max_latency))
-		atomic_set(&current_max_latency, usecs);
-
-	spin_unlock_irqrestore(&latency_lock, flags);
-
-	blocking_notifier_call_chain(&latency_notifier,
-		atomic_read(&current_max_latency), NULL);
-
-	/*
-	 * if we inserted the new one, we're done; otherwise there was
-	 * an existing one so we need to free the redundant data
-	 */
-	if (!found_old)
-		return;
-
-	kfree(info->identifier);
-free_info:
-	kfree(info);
-}
-EXPORT_SYMBOL_GPL(set_acceptable_latency);
-
-/**
- * modify_acceptable_latency - changes the maximum latency acceptable
- * @identifier: string that identifies this driver
- * @usecs: maximum acceptable latency for this driver
- *
- * This function informs the kernel that this device(driver)
- * can accept at most usecs latency. This setting is used for
- * power management and similar tradeoffs.
- *
- * This function does not sleep and can be called in any context.
- * Trying to use a non-existing identifier silently gets ignored.
- *
- * Due to the atomic nature of this function, the modified latency
- * value will only be used for future decisions; past decisions
- * can still lead to longer latencies in the near future.
- */
-void modify_acceptable_latency(char *identifier, int usecs)
-{
-	struct latency_info *iter;
-	unsigned long flags;
-
-	spin_lock_irqsave(&latency_lock, flags);
-	list_for_each_entry(iter, &latency_list, list) {
-		if (strcmp(iter->identifier, identifier) == 0) {
-			iter->usecs = usecs;
-			break;
-		}
-	}
-	if (usecs < atomic_read(&current_max_latency))
-		atomic_set(&current_max_latency, usecs);
-	spin_unlock_irqrestore(&latency_lock, flags);
-}
-EXPORT_SYMBOL_GPL(modify_acceptable_latency);
-
-/**
- * remove_acceptable_latency - removes the maximum latency acceptable
- * @identifier: string that identifies this driver
- *
- * This function removes a previously set maximum latency setting
- * for the driver and frees up any resources associated with the
- * bookkeeping needed for this.
- *
- * This function does not sleep and can be called in any context.
- * Trying to use a non-existing identifier silently gets ignored.
- */
-void remove_acceptable_latency(char *identifier)
-{
-	unsigned long flags;
-	int newmax = 0;
-	struct latency_info *iter, *temp;
-
-	spin_lock_irqsave(&latency_lock, flags);
-
-	list_for_each_entry_safe(iter,  temp, &latency_list, list) {
-		if (strcmp(iter->identifier, identifier) == 0) {
-			list_del(&iter->list);
-			newmax = iter->usecs;
-			kfree(iter->identifier);
-			kfree(iter);
-			break;
-		}
-	}
-
-	/* If we just deleted the system wide value, we need to
-	 * recalculate with a full search
-	 */
-	if (newmax == atomic_read(&current_max_latency)) {
-		newmax = __find_max_latency();
-		atomic_set(&current_max_latency, newmax);
-	}
-	spin_unlock_irqrestore(&latency_lock, flags);
-}
-EXPORT_SYMBOL_GPL(remove_acceptable_latency);
-
-/**
- * system_latency_constraint - queries the system wide latency maximum
- *
- * This function returns the system wide maximum latency in
- * microseconds.
- *
- * This function does not sleep and can be called in any context.
- */
-int system_latency_constraint(void)
-{
-	return atomic_read(&current_max_latency);
-}
-EXPORT_SYMBOL_GPL(system_latency_constraint);
-
-/**
- * synchronize_acceptable_latency - recalculates all latency decisions
- *
- * This function will cause a callback to various kernel pieces that
- * will make those pieces rethink their latency decisions. This implies
- * that if there are overlong latencies in hardware state already, those
- * latencies get taken right now. When this call completes no overlong
- * latency decisions should be active anymore.
- *
- * Typical usecase of this is after a modify_acceptable_latency() call,
- * which in itself is non-blocking and non-synchronizing.
- *
- * This function blocks and should not be called with locks held.
- */
-
-void synchronize_acceptable_latency(void)
-{
-	blocking_notifier_call_chain(&latency_notifier,
-		atomic_read(&current_max_latency), NULL);
-}
-EXPORT_SYMBOL_GPL(synchronize_acceptable_latency);
-
-/*
- * Latency notifier: this notifier gets called when a non-atomic new
- * latency value gets set. The expectation nof the caller of the
- * non-atomic set is that when the call returns, future latencies
- * are within bounds, so the functions on the notifier list are
- * expected to take the overlong latencies immediately, inside the
- * callback, and not make a overlong latency decision anymore.
- *
- * The callback gets called when the new latency value is made
- * active so system_latency_constraint() returns the new latency.
- */
-int register_latency_notifier(struct notifier_block * nb)
-{
-	return blocking_notifier_chain_register(&latency_notifier, nb);
-}
-EXPORT_SYMBOL_GPL(register_latency_notifier);
-
-int unregister_latency_notifier(struct notifier_block * nb)
-{
-	return blocking_notifier_chain_unregister(&latency_notifier, nb);
-}
-EXPORT_SYMBOL_GPL(unregister_latency_notifier);
-
-static __init int latency_init(void)
-{
-	atomic_set(&current_max_latency, INFINITE_LATENCY);
-	/*
-	 * we don't want by default to have longer latencies than 2 ticks,
-	 * since that would cause lost ticks
-	 */
-	set_acceptable_latency("kernel", 2*1000000/HZ);
-	return 0;
-}
-
-module_init(latency_init);
diff -urN -X linux-2.6.23-rc8/Documentation/dontdiff linux-2.6.23-rc8-qos/kernel/Makefile linux-2.6.23-rc8-qos-nolatency.c/kernel/Makefile
--- linux-2.6.23-rc8-qos/kernel/Makefile	2007-10-01 11:13:35.000000000 -0700
+++ linux-2.6.23-rc8-qos-nolatency.c/kernel/Makefile	2007-10-01 11:15:31.000000000 -0700
@@ -8,7 +8,7 @@
 	    signal.o sys.o kmod.o workqueue.o pid.o \
 	    rcupdate.o extable.o params.o posix-timers.o \
 	    kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \
-	    hrtimer.o rwsem.o latency.o nsproxy.o srcu.o die_notifier.o \
+	    hrtimer.o rwsem.o nsproxy.o srcu.o die_notifier.o \
 	    utsname.o pm_qos_params.o
 
 obj-$(CONFIG_STACKTRACE) += stacktrace.o
diff -urN -X linux-2.6.23-rc8/Documentation/dontdiff linux-2.6.23-rc8-qos/sound/core/pcm_native.c linux-2.6.23-rc8-qos-nolatency.c/sound/core/pcm_native.c
--- linux-2.6.23-rc8-qos/sound/core/pcm_native.c	2007-09-26 13:54:57.000000000 -0700
+++ linux-2.6.23-rc8-qos-nolatency.c/sound/core/pcm_native.c	2007-10-01 12:33:36.000000000 -0700
@@ -24,7 +24,7 @@
 #include <linux/file.h>
 #include <linux/slab.h>
 #include <linux/time.h>
-#include <linux/latency.h>
+#include <linux/pm_qos_params.h>
 #include <linux/uio.h>
 #include <sound/core.h>
 #include <sound/control.h>
@@ -447,9 +447,11 @@
 	snd_pcm_timer_resolution_change(substream);
 	runtime->status->state = SNDRV_PCM_STATE_SETUP;
 
-	remove_acceptable_latency(substream->latency_id);
+	pm_qos_remove_requirement(PM_QOS_CPU_DMA_LATENCY,
+				substream->latency_id);
 	if ((usecs = period_to_usecs(runtime)) >= 0)
-		set_acceptable_latency(substream->latency_id, usecs);
+		pm_qos_add_requirement(PM_QOS_CPU_DMA_LATENCY,
+					substream->latency_id, usecs);
 	return 0;
  _error:
 	/* hardware might be unuseable from this time,
@@ -509,7 +511,8 @@
 	if (substream->ops->hw_free)
 		result = substream->ops->hw_free(substream);
 	runtime->status->state = SNDRV_PCM_STATE_OPEN;
-	remove_acceptable_latency(substream->latency_id);
+	pm_qos_remove_requirement(PM_QOS_CPU_DMA_LATENCY,
+		substream->latency_id);
 	return result;
 }
 

Re: [PATCH] PM_QOS 2 of 2

[Mark Gross]

this is the second part of the patch to replace latency.c use with
pm_qos_params use.


--mgross



Signed-off-by: mark gross <mgross@linux.intel.com>

-----------

diff -urN -X linux-2.6.23-rc8/Documentation/dontdiff linux-2.6.23-rc8-qos/drivers/acpi/processor_idle.c linux-2.6.23-rc8-qos-nolatency.c/drivers/acpi/processor_idle.c
--- linux-2.6.23-rc8-qos/drivers/acpi/processor_idle.c	2007-09-26 13:54:28.000000000 -0700
+++ linux-2.6.23-rc8-qos-nolatency.c/drivers/acpi/processor_idle.c	2007-10-01 11:32:13.000000000 -0700
@@ -38,7 +38,7 @@
 #include <linux/dmi.h>
 #include <linux/moduleparam.h>
 #include <linux/sched.h>	/* need_resched() */
-#include <linux/latency.h>
+#include <linux/pm_qos_params.h>
 #include <linux/clockchips.h>
 
 /*
@@ -605,7 +605,8 @@
 	if (cx->promotion.state &&
 	    ((cx->promotion.state - pr->power.states) <= max_cstate)) {
 		if (sleep_ticks > cx->promotion.threshold.ticks &&
-		  cx->promotion.state->latency <= system_latency_constraint()) {
+		  cx->promotion.state->latency <=
+				pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY)) {
 			cx->promotion.count++;
 			cx->demotion.count = 0;
 			if (cx->promotion.count >=
@@ -649,7 +650,8 @@
 	 * or if the latency of the current state is unacceptable
 	 */
 	if ((pr->power.state - pr->power.states) > max_cstate ||
-		pr->power.state->latency > system_latency_constraint()) {
+		pr->power.state->latency >
+				pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY)) {
 		if (cx->demotion.state)
 			next_state = cx->demotion.state;
 	}
@@ -1173,7 +1175,7 @@
 		   "maximum allowed latency: %d usec\n",
 		   pr->power.state ? pr->power.state - pr->power.states : 0,
 		   max_cstate, (unsigned)pr->power.bm_activity,
-		   system_latency_constraint());
+		   pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY));
 
 	seq_puts(seq, "states:\n");
 
@@ -1280,7 +1282,8 @@
 			       max_cstate);
 		first_run++;
 #ifdef CONFIG_SMP
-		register_latency_notifier(&acpi_processor_latency_notifier);
+		pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY,
+				&acpi_processor_latency_notifier);
 #endif
 	}
 
@@ -1354,7 +1357,8 @@
 		 */
 		cpu_idle_wait();
 #ifdef CONFIG_SMP
-		unregister_latency_notifier(&acpi_processor_latency_notifier);
+		pm_qos_remove_notifier(PM_QOS_CPU_DMA_LATENCY,
+				&acpi_processor_latency_notifier);
 #endif
 	}
 
diff -urN -X linux-2.6.23-rc8/Documentation/dontdiff linux-2.6.23-rc8-qos/drivers/net/wireless/ipw2100.c linux-2.6.23-rc8-qos-nolatency.c/drivers/net/wireless/ipw2100.c
--- linux-2.6.23-rc8-qos/drivers/net/wireless/ipw2100.c	2007-09-26 13:54:34.000000000 -0700
+++ linux-2.6.23-rc8-qos-nolatency.c/drivers/net/wireless/ipw2100.c	2007-10-01 12:32:56.000000000 -0700
@@ -162,7 +162,7 @@
 #include <linux/firmware.h>
 #include <linux/acpi.h>
 #include <linux/ctype.h>
-#include <linux/latency.h>
+#include <linux/pm_qos_params.h>
 
 #include "ipw2100.h"
 
@@ -1701,7 +1701,7 @@
 	/* the ipw2100 hardware really doesn't want power management delays
 	 * longer than 175usec
 	 */
-	modify_acceptable_latency("ipw2100", 175);
+	pm_qos_update_requirement(PM_QOS_CPU_DMA_LATENCY, "ipw2100", 175);
 
 	/* If the interrupt is enabled, turn it off... */
 	spin_lock_irqsave(&priv->low_lock, flags);
@@ -1856,7 +1856,8 @@
 	ipw2100_disable_interrupts(priv);
 	spin_unlock_irqrestore(&priv->low_lock, flags);
 
-	modify_acceptable_latency("ipw2100", INFINITE_LATENCY);
+	pm_qos_update_requirement(PM_QOS_CPU_DMA_LATENCY, "ipw2100",
+			PM_QOS_DEFAULT_VALUE);
 
 #ifdef ACPI_CSTATE_LIMIT_DEFINED
 	if (priv->config & CFG_C3_DISABLED) {
@@ -6544,7 +6545,8 @@
 	if (ret)
 		goto out;
 
-	set_acceptable_latency("ipw2100", INFINITE_LATENCY);
+	pm_qos_add_requirement(PM_QOS_CPU_DMA_LATENCY, "ipw2100",
+			PM_QOS_DEFAULT_VALUE);
 #ifdef CONFIG_IPW2100_DEBUG
 	ipw2100_debug_level = debug;
 	ret = driver_create_file(&ipw2100_pci_driver.driver,
@@ -6566,7 +6568,7 @@
 			   &driver_attr_debug_level);
 #endif
 	pci_unregister_driver(&ipw2100_pci_driver);
-	remove_acceptable_latency("ipw2100");
+	pm_qos_remove_requirement(PM_QOS_CPU_DMA_LATENCY, "ipw2100");
 }
 
 module_init(ipw2100_init);
diff -urN -X linux-2.6.23-rc8/Documentation/dontdiff linux-2.6.23-rc8-qos/include/linux/latency.h linux-2.6.23-rc8-qos-nolatency.c/include/linux/latency.h
--- linux-2.6.23-rc8-qos/include/linux/latency.h	2007-07-08 16:32:17.000000000 -0700
+++ linux-2.6.23-rc8-qos-nolatency.c/include/linux/latency.h	1969-12-31 16:00:00.000000000 -0800
@@ -1,25 +0,0 @@
-/*
- * latency.h: Explicit system-wide latency-expectation infrastructure
- *
- * (C) Copyright 2006 Intel Corporation
- * Author: Arjan van de Ven <arjan@linux.intel.com>
- *
- */
-
-#ifndef _INCLUDE_GUARD_LATENCY_H_
-#define _INCLUDE_GUARD_LATENCY_H_
-
-#include <linux/notifier.h>
-
-void set_acceptable_latency(char *identifier, int usecs);
-void modify_acceptable_latency(char *identifier, int usecs);
-void remove_acceptable_latency(char *identifier);
-void synchronize_acceptable_latency(void);
-int system_latency_constraint(void);
-
-int register_latency_notifier(struct notifier_block * nb);
-int unregister_latency_notifier(struct notifier_block * nb);
-
-#define INFINITE_LATENCY 1000000
-
-#endif
diff -urN -X linux-2.6.23-rc8/Documentation/dontdiff linux-2.6.23-rc8-qos/kernel/latency.c linux-2.6.23-rc8-qos-nolatency.c/kernel/latency.c
--- linux-2.6.23-rc8-qos/kernel/latency.c	2007-07-08 16:32:17.000000000 -0700
+++ linux-2.6.23-rc8-qos-nolatency.c/kernel/latency.c	1969-12-31 16:00:00.000000000 -0800
@@ -1,280 +0,0 @@
-/*
- * latency.c: Explicit system-wide latency-expectation infrastructure
- *
- * The purpose of this infrastructure is to allow device drivers to set
- * latency constraint they have and to collect and summarize these
- * expectations globally. The cummulated result can then be used by
- * power management and similar users to make decisions that have
- * tradoffs with a latency component.
- *
- * An example user of this are the x86 C-states; each higher C state saves
- * more power, but has a higher exit latency. For the idle loop power
- * code to make a good decision which C-state to use, information about
- * acceptable latencies is required.
- *
- * An example announcer of latency is an audio driver that knowns it
- * will get an interrupt when the hardware has 200 usec of samples
- * left in the DMA buffer; in that case the driver can set a latency
- * constraint of, say, 150 usec.
- *
- * Multiple drivers can each announce their maximum accepted latency,
- * to keep these appart, a string based identifier is used.
- *
- *
- * (C) Copyright 2006 Intel Corporation
- * Author: Arjan van de Ven <arjan@linux.intel.com>
- *
- * 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; version 2
- * of the License.
- */
-
-#include <linux/latency.h>
-#include <linux/list.h>
-#include <linux/spinlock.h>
-#include <linux/slab.h>
-#include <linux/module.h>
-#include <linux/notifier.h>
-#include <linux/jiffies.h>
-#include <asm/atomic.h>
-
-struct latency_info {
-	struct list_head list;
-	int usecs;
-	char *identifier;
-};
-
-/*
- * locking rule: all modifications to current_max_latency and
- * latency_list need to be done while holding the latency_lock.
- * latency_lock needs to be taken _irqsave.
- */
-static atomic_t current_max_latency;
-static DEFINE_SPINLOCK(latency_lock);
-
-static LIST_HEAD(latency_list);
-static BLOCKING_NOTIFIER_HEAD(latency_notifier);
-
-/*
- * This function returns the maximum latency allowed, which
- * happens to be the minimum of all maximum latencies on the
- * list.
- */
-static int __find_max_latency(void)
-{
-	int min = INFINITE_LATENCY;
-	struct latency_info *info;
-
-	list_for_each_entry(info, &latency_list, list) {
-		if (info->usecs < min)
-			min = info->usecs;
-	}
-	return min;
-}
-
-/**
- * set_acceptable_latency - sets the maximum latency acceptable
- * @identifier: string that identifies this driver
- * @usecs: maximum acceptable latency for this driver
- *
- * This function informs the kernel that this device(driver)
- * can accept at most usecs latency. This setting is used for
- * power management and similar tradeoffs.
- *
- * This function sleeps and can only be called from process
- * context.
- * Calling this function with an existing identifier is valid
- * and will cause the existing latency setting to be changed.
- */
-void set_acceptable_latency(char *identifier, int usecs)
-{
-	struct latency_info *info, *iter;
-	unsigned long flags;
-	int found_old = 0;
-
-	info = kzalloc(sizeof(struct latency_info), GFP_KERNEL);
-	if (!info)
-		return;
-	info->usecs = usecs;
-	info->identifier = kstrdup(identifier, GFP_KERNEL);
-	if (!info->identifier)
-		goto free_info;
-
-	spin_lock_irqsave(&latency_lock, flags);
-	list_for_each_entry(iter, &latency_list, list) {
-		if (strcmp(iter->identifier, identifier)==0) {
-			found_old = 1;
-			iter->usecs = usecs;
-			break;
-		}
-	}
-	if (!found_old)
-		list_add(&info->list, &latency_list);
-
-	if (usecs < atomic_read(&current_max_latency))
-		atomic_set(&current_max_latency, usecs);
-
-	spin_unlock_irqrestore(&latency_lock, flags);
-
-	blocking_notifier_call_chain(&latency_notifier,
-		atomic_read(&current_max_latency), NULL);
-
-	/*
-	 * if we inserted the new one, we're done; otherwise there was
-	 * an existing one so we need to free the redundant data
-	 */
-	if (!found_old)
-		return;
-
-	kfree(info->identifier);
-free_info:
-	kfree(info);
-}
-EXPORT_SYMBOL_GPL(set_acceptable_latency);
-
-/**
- * modify_acceptable_latency - changes the maximum latency acceptable
- * @identifier: string that identifies this driver
- * @usecs: maximum acceptable latency for this driver
- *
- * This function informs the kernel that this device(driver)
- * can accept at most usecs latency. This setting is used for
- * power management and similar tradeoffs.
- *
- * This function does not sleep and can be called in any context.
- * Trying to use a non-existing identifier silently gets ignored.
- *
- * Due to the atomic nature of this function, the modified latency
- * value will only be used for future decisions; past decisions
- * can still lead to longer latencies in the near future.
- */
-void modify_acceptable_latency(char *identifier, int usecs)
-{
-	struct latency_info *iter;
-	unsigned long flags;
-
-	spin_lock_irqsave(&latency_lock, flags);
-	list_for_each_entry(iter, &latency_list, list) {
-		if (strcmp(iter->identifier, identifier) == 0) {
-			iter->usecs = usecs;
-			break;
-		}
-	}
-	if (usecs < atomic_read(&current_max_latency))
-		atomic_set(&current_max_latency, usecs);
-	spin_unlock_irqrestore(&latency_lock, flags);
-}
-EXPORT_SYMBOL_GPL(modify_acceptable_latency);
-
-/**
- * remove_acceptable_latency - removes the maximum latency acceptable
- * @identifier: string that identifies this driver
- *
- * This function removes a previously set maximum latency setting
- * for the driver and frees up any resources associated with the
- * bookkeeping needed for this.
- *
- * This function does not sleep and can be called in any context.
- * Trying to use a non-existing identifier silently gets ignored.
- */
-void remove_acceptable_latency(char *identifier)
-{
-	unsigned long flags;
-	int newmax = 0;
-	struct latency_info *iter, *temp;
-
-	spin_lock_irqsave(&latency_lock, flags);
-
-	list_for_each_entry_safe(iter,  temp, &latency_list, list) {
-		if (strcmp(iter->identifier, identifier) == 0) {
-			list_del(&iter->list);
-			newmax = iter->usecs;
-			kfree(iter->identifier);
-			kfree(iter);
-			break;
-		}
-	}
-
-	/* If we just deleted the system wide value, we need to
-	 * recalculate with a full search
-	 */
-	if (newmax == atomic_read(&current_max_latency)) {
-		newmax = __find_max_latency();
-		atomic_set(&current_max_latency, newmax);
-	}
-	spin_unlock_irqrestore(&latency_lock, flags);
-}
-EXPORT_SYMBOL_GPL(remove_acceptable_latency);
-
-/**
- * system_latency_constraint - queries the system wide latency maximum
- *
- * This function returns the system wide maximum latency in
- * microseconds.
- *
- * This function does not sleep and can be called in any context.
- */
-int system_latency_constraint(void)
-{
-	return atomic_read(&current_max_latency);
-}
-EXPORT_SYMBOL_GPL(system_latency_constraint);
-
-/**
- * synchronize_acceptable_latency - recalculates all latency decisions
- *
- * This function will cause a callback to various kernel pieces that
- * will make those pieces rethink their latency decisions. This implies
- * that if there are overlong latencies in hardware state already, those
- * latencies get taken right now. When this call completes no overlong
- * latency decisions should be active anymore.
- *
- * Typical usecase of this is after a modify_acceptable_latency() call,
- * which in itself is non-blocking and non-synchronizing.
- *
- * This function blocks and should not be called with locks held.
- */
-
-void synchronize_acceptable_latency(void)
-{
-	blocking_notifier_call_chain(&latency_notifier,
-		atomic_read(&current_max_latency), NULL);
-}
-EXPORT_SYMBOL_GPL(synchronize_acceptable_latency);
-
-/*
- * Latency notifier: this notifier gets called when a non-atomic new
- * latency value gets set. The expectation nof the caller of the
- * non-atomic set is that when the call returns, future latencies
- * are within bounds, so the functions on the notifier list are
- * expected to take the overlong latencies immediately, inside the
- * callback, and not make a overlong latency decision anymore.
- *
- * The callback gets called when the new latency value is made
- * active so system_latency_constraint() returns the new latency.
- */
-int register_latency_notifier(struct notifier_block * nb)
-{
-	return blocking_notifier_chain_register(&latency_notifier, nb);
-}
-EXPORT_SYMBOL_GPL(register_latency_notifier);
-
-int unregister_latency_notifier(struct notifier_block * nb)
-{
-	return blocking_notifier_chain_unregister(&latency_notifier, nb);
-}
-EXPORT_SYMBOL_GPL(unregister_latency_notifier);
-
-static __init int latency_init(void)
-{
-	atomic_set(&current_max_latency, INFINITE_LATENCY);
-	/*
-	 * we don't want by default to have longer latencies than 2 ticks,
-	 * since that would cause lost ticks
-	 */
-	set_acceptable_latency("kernel", 2*1000000/HZ);
-	return 0;
-}
-
-module_init(latency_init);
diff -urN -X linux-2.6.23-rc8/Documentation/dontdiff linux-2.6.23-rc8-qos/kernel/Makefile linux-2.6.23-rc8-qos-nolatency.c/kernel/Makefile
--- linux-2.6.23-rc8-qos/kernel/Makefile	2007-10-01 11:13:35.000000000 -0700
+++ linux-2.6.23-rc8-qos-nolatency.c/kernel/Makefile	2007-10-01 11:15:31.000000000 -0700
@@ -8,7 +8,7 @@
 	    signal.o sys.o kmod.o workqueue.o pid.o \
 	    rcupdate.o extable.o params.o posix-timers.o \
 	    kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \
-	    hrtimer.o rwsem.o latency.o nsproxy.o srcu.o die_notifier.o \
+	    hrtimer.o rwsem.o nsproxy.o srcu.o die_notifier.o \
 	    utsname.o pm_qos_params.o
 
 obj-$(CONFIG_STACKTRACE) += stacktrace.o
diff -urN -X linux-2.6.23-rc8/Documentation/dontdiff linux-2.6.23-rc8-qos/sound/core/pcm_native.c linux-2.6.23-rc8-qos-nolatency.c/sound/core/pcm_native.c
--- linux-2.6.23-rc8-qos/sound/core/pcm_native.c	2007-09-26 13:54:57.000000000 -0700
+++ linux-2.6.23-rc8-qos-nolatency.c/sound/core/pcm_native.c	2007-10-01 12:33:36.000000000 -0700
@@ -24,7 +24,7 @@
 #include <linux/file.h>
 #include <linux/slab.h>
 #include <linux/time.h>
-#include <linux/latency.h>
+#include <linux/pm_qos_params.h>
 #include <linux/uio.h>
 #include <sound/core.h>
 #include <sound/control.h>
@@ -447,9 +447,11 @@
 	snd_pcm_timer_resolution_change(substream);
 	runtime->status->state = SNDRV_PCM_STATE_SETUP;
 
-	remove_acceptable_latency(substream->latency_id);
+	pm_qos_remove_requirement(PM_QOS_CPU_DMA_LATENCY,
+				substream->latency_id);
 	if ((usecs = period_to_usecs(runtime)) >= 0)
-		set_acceptable_latency(substream->latency_id, usecs);
+		pm_qos_add_requirement(PM_QOS_CPU_DMA_LATENCY,
+					substream->latency_id, usecs);
 	return 0;
  _error:
 	/* hardware might be unuseable from this time,
@@ -509,7 +511,8 @@
 	if (substream->ops->hw_free)
 		result = substream->ops->hw_free(substream);
 	runtime->status->state = SNDRV_PCM_STATE_OPEN;
-	remove_acceptable_latency(substream->latency_id);
+	pm_qos_remove_requirement(PM_QOS_CPU_DMA_LATENCY,
+		substream->latency_id);
 	return result;
 }
 

Re: [PATCH] PM_QOS 1 of 2

[Andrew Morton]

On Mon, 1 Oct 2007 16:45:28 -0700
Mark Gross <mgross@linux.intel.com> wrote:

> The following is the cleaned up patch implementing the power management
> quality of service infrastructure discussed at the pm summit last June.
> 
> It is a genralization of the latency code put into the kernel last year
> by Arjan.
> 
> I would like to get this code included in the MM tree and to get some
> milage on it.
> 
> One thing to note about this implementation is that it exposes an
> interface to user space for registering pm_qos constraints in addition
> to the kernel exports.  Its a file based interface where a module can
> register a constraint and the constraint is valid only as long as the
> device node is held open.  Upon closing of the device node that
> constraint is cleaned up.
> 
> The patch set is in two postings.  
> 1) the base parameter code (this email)
> 2) replacing of latency.c/latenc.h with pm_qos_params.c/pm_qos_params.h

I wouldn't really view this as an adequate changelog.

- The Subject:s are pretty pathetic (please see my suggesed replacements)

- There is no description of the proposed new kernel<->userspace
  interfaces.

  As you are proposing new and permanent enhancements to the Linux API,
  this is something which should be spelled out in some detail.  Because we
  can change the implementation, but we can not ever change your interface.

  It would be nice to get that interface described in Documentation/
  somewhere, but it is *critical* that the design be fully revealed right
  now, during review.


Anyway, I am not a suitable person to review this submission.

I'll put the patches in -mm for a bit of eyeball-and-test (not that anyone
will know how to test it, due to the secret interfaces) but I do not want
to move this code into mainline until someone who is familiar with the PM
code has performed a detailed review of both the implementation and the
design (whatever that is!).

Please send new, complete descriptions of these patches.  I don't think
they can be effectively reviewed without that information.  Except perhaps
by someone who was at the PM summit, but that's cheating.


Thanks.

Re: [PATCH] PM_QOS 1 of 2

[Andrew Morton]

On Mon, 1 Oct 2007 16:45:28 -0700
Mark Gross <mgross@linux.intel.com> wrote:

> The following is the cleaned up patch implementing the power management
> quality of service infrastructure discussed at the pm summit last June.
> 
> It is a genralization of the latency code put into the kernel last year
> by Arjan.
> 
> I would like to get this code included in the MM tree and to get some
> milage on it.
> 
> One thing to note about this implementation is that it exposes an
> interface to user space for registering pm_qos constraints in addition
> to the kernel exports.  Its a file based interface where a module can
> register a constraint and the constraint is valid only as long as the
> device node is held open.  Upon closing of the device node that
> constraint is cleaned up.
> 
> The patch set is in two postings.  
> 1) the base parameter code (this email)
> 2) replacing of latency.c/latenc.h with pm_qos_params.c/pm_qos_params.h

I wouldn't really view this as an adequate changelog.

- The Subject:s are pretty pathetic (please see my suggesed replacements)

- There is no description of the proposed new kernel<->userspace
  interfaces.

  As you are proposing new and permanent enhancements to the Linux API,
  this is something which should be spelled out in some detail.  Because we
  can change the implementation, but we can not ever change your interface.

  It would be nice to get that interface described in Documentation/
  somewhere, but it is *critical* that the design be fully revealed right
  now, during review.


Anyway, I am not a suitable person to review this submission.

I'll put the patches in -mm for a bit of eyeball-and-test (not that anyone
will know how to test it, due to the secret interfaces) but I do not want
to move this code into mainline until someone who is familiar with the PM
code has performed a detailed review of both the implementation and the
design (whatever that is!).

Please send new, complete descriptions of these patches.  I don't think
they can be effectively reviewed without that information.  Except perhaps
by someone who was at the PM summit, but that's cheating.


Thanks.

Re: [PATCH] PM_QOS 1 of 2

[Mark Gross]

On Thu, Oct 04, 2007 at 12:53:56PM -0700, Andrew Morton wrote:
> On Mon, 1 Oct 2007 16:45:28 -0700
> Mark Gross <mgross@linux.intel.com> wrote:
> 
> > The following is the cleaned up patch implementing the power management
> > quality of service infrastructure discussed at the pm summit last June.
> > 
> > It is a genralization of the latency code put into the kernel last year
> > by Arjan.
> > 
> > I would like to get this code included in the MM tree and to get some
> > milage on it.
> > 
> > One thing to note about this implementation is that it exposes an
> > interface to user space for registering pm_qos constraints in addition
> > to the kernel exports.  Its a file based interface where a module can
> > register a constraint and the constraint is valid only as long as the
> > device node is held open.  Upon closing of the device node that
> > constraint is cleaned up.
> > 
> > The patch set is in two postings.  
> > 1) the base parameter code (this email)
> > 2) replacing of latency.c/latenc.h with pm_qos_params.c/pm_qos_params.h
> 
> I wouldn't really view this as an adequate changelog.
> 
> - The Subject:s are pretty pathetic (please see my suggesed replacements)

uhg.  Your right.

> 
> - There is no description of the proposed new kernel<->userspace
>   interfaces.
> 

the above description is light on specific details. 

>   As you are proposing new and permanent enhancements to the Linux API,
>   this is something which should be spelled out in some detail.  Because we
>   can change the implementation, but we can not ever change your interface.
> 
>   It would be nice to get that interface described in Documentation/
>   somewhere, but it is *critical* that the design be fully revealed right
>   now, during review.

I'll provide this.

> 
> 
> Anyway, I am not a suitable person to review this submission.
> 
> I'll put the patches in -mm for a bit of eyeball-and-test (not that anyone
> will know how to test it, due to the secret interfaces) but I do not want
> to move this code into mainline until someone who is familiar with the PM
> code has performed a detailed review of both the implementation and the
> design (whatever that is!).
> 
> Please send new, complete descriptions of these patches.  I don't think
> they can be effectively reviewed without that information.  Except perhaps
> by someone who was at the PM summit, but that's cheating.
> 

I will do this.

--mgross

Re: [PATCH] PM_QOS 1 of 2

[Mark Gross]

On Thu, Oct 04, 2007 at 12:53:56PM -0700, Andrew Morton wrote:
> On Mon, 1 Oct 2007 16:45:28 -0700
> Mark Gross <mgross@linux.intel.com> wrote:
> 
> > The following is the cleaned up patch implementing the power management
> > quality of service infrastructure discussed at the pm summit last June.
> > 
> > It is a genralization of the latency code put into the kernel last year
> > by Arjan.
> > 
> > I would like to get this code included in the MM tree and to get some
> > milage on it.
> > 
> > One thing to note about this implementation is that it exposes an
> > interface to user space for registering pm_qos constraints in addition
> > to the kernel exports.  Its a file based interface where a module can
> > register a constraint and the constraint is valid only as long as the
> > device node is held open.  Upon closing of the device node that
> > constraint is cleaned up.
> > 
> > The patch set is in two postings.  
> > 1) the base parameter code (this email)
> > 2) replacing of latency.c/latenc.h with pm_qos_params.c/pm_qos_params.h
> 
> I wouldn't really view this as an adequate changelog.
> 
> - The Subject:s are pretty pathetic (please see my suggesed replacements)

uhg.  Your right.

> 
> - There is no description of the proposed new kernel<->userspace
>   interfaces.
> 

the above description is light on specific details. 

>   As you are proposing new and permanent enhancements to the Linux API,
>   this is something which should be spelled out in some detail.  Because we
>   can change the implementation, but we can not ever change your interface.
> 
>   It would be nice to get that interface described in Documentation/
>   somewhere, but it is *critical* that the design be fully revealed right
>   now, during review.

I'll provide this.

> 
> 
> Anyway, I am not a suitable person to review this submission.
> 
> I'll put the patches in -mm for a bit of eyeball-and-test (not that anyone
> will know how to test it, due to the secret interfaces) but I do not want
> to move this code into mainline until someone who is familiar with the PM
> code has performed a detailed review of both the implementation and the
> design (whatever that is!).
> 
> Please send new, complete descriptions of these patches.  I don't think
> they can be effectively reviewed without that information.  Except perhaps
> by someone who was at the PM summit, but that's cheating.
> 

I will do this.

--mgross