* 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
+ * Dependents on a QoS value : register requests
* Watchers of QoS value : get notified when target QoS value changes
*
* This QoS design is best effort based. Dependents register their QoS needs.
* timeout: usec <-- currently not used.
* throughput: kbs (kilo byte / sec)
*
- * There are lists of pm_qos_objects each one wrapping requirements, notifiers
+ * There are lists of pm_qos_objects each one wrapping requests, notifiers
*
- * User mode requirements on a QOS parameter register themselves to the
+ * User mode requests 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
+ * request is removed and a new qos target is computed. This way when the
+ * request 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>
*/
+/*#define DEBUG*/
+
#include <linux/pm_qos_params.h>
#include <linux/sched.h>
-#include <linux/smp_lock.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/uaccess.h>
/*
- * locking rule: all changes to target_value or requirements or notifiers lists
+ * locking rule: all changes to requests 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 requirement_list {
+struct pm_qos_request_list {
struct list_head list;
union {
s32 value;
s32 usec;
s32 kbps;
};
- char *name;
+ int pm_qos_class;
};
static s32 max_compare(s32 v1, s32 v2);
static s32 min_compare(s32 v1, s32 v2);
struct pm_qos_object {
- struct requirement_list requirements;
+ struct pm_qos_request_list requests;
struct blocking_notifier_head *notifiers;
struct miscdevice pm_qos_power_miscdev;
char *name;
s32 default_value;
- s32 target_value;
+ atomic_t target_value;
s32 (*comparitor)(s32, s32);
};
static struct pm_qos_object null_pm_qos;
static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier);
static struct pm_qos_object cpu_dma_pm_qos = {
- .requirements = {LIST_HEAD_INIT(cpu_dma_pm_qos.requirements.list)},
+ .requests = {LIST_HEAD_INIT(cpu_dma_pm_qos.requests.list)},
.notifiers = &cpu_dma_lat_notifier,
.name = "cpu_dma_latency",
.default_value = 2000 * USEC_PER_SEC,
- .target_value = 2000 * USEC_PER_SEC,
+ .target_value = ATOMIC_INIT(2000 * USEC_PER_SEC),
.comparitor = min_compare
};
static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);
static struct pm_qos_object network_lat_pm_qos = {
- .requirements = {LIST_HEAD_INIT(network_lat_pm_qos.requirements.list)},
+ .requests = {LIST_HEAD_INIT(network_lat_pm_qos.requests.list)},
.notifiers = &network_lat_notifier,
.name = "network_latency",
.default_value = 2000 * USEC_PER_SEC,
- .target_value = 2000 * USEC_PER_SEC,
+ .target_value = ATOMIC_INIT(2000 * USEC_PER_SEC),
.comparitor = min_compare
};
static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier);
static struct pm_qos_object network_throughput_pm_qos = {
- .requirements =
- {LIST_HEAD_INIT(network_throughput_pm_qos.requirements.list)},
+ .requests = {LIST_HEAD_INIT(network_throughput_pm_qos.requests.list)},
.notifiers = &network_throughput_notifier,
.name = "network_throughput",
.default_value = 0,
- .target_value = 0,
+ .target_value = ATOMIC_INIT(0),
.comparitor = max_compare
};
}
-static void update_target(int target)
+static void update_target(int pm_qos_class)
{
s32 extreme_value;
- struct requirement_list *node;
+ struct pm_qos_request_list *node;
unsigned long flags;
int call_notifier = 0;
spin_lock_irqsave(&pm_qos_lock, flags);
- extreme_value = pm_qos_array[target]->default_value;
+ extreme_value = pm_qos_array[pm_qos_class]->default_value;
list_for_each_entry(node,
- &pm_qos_array[target]->requirements.list, list) {
- extreme_value = pm_qos_array[target]->comparitor(
+ &pm_qos_array[pm_qos_class]->requests.list, list) {
+ extreme_value = pm_qos_array[pm_qos_class]->comparitor(
extreme_value, node->value);
}
- if (pm_qos_array[target]->target_value != extreme_value) {
+ if (atomic_read(&pm_qos_array[pm_qos_class]->target_value) !=
+ extreme_value) {
call_notifier = 1;
- 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);
+ atomic_set(&pm_qos_array[pm_qos_class]->target_value,
+ extreme_value);
+ pr_debug(KERN_ERR "new target for qos %d is %d\n", pm_qos_class,
+ atomic_read(&pm_qos_array[pm_qos_class]->target_value));
}
spin_unlock_irqrestore(&pm_qos_lock, flags);
if (call_notifier)
- blocking_notifier_call_chain(pm_qos_array[target]->notifiers,
- (unsigned long) extreme_value, NULL);
+ blocking_notifier_call_chain(
+ pm_qos_array[pm_qos_class]->notifiers,
+ (unsigned long) extreme_value, NULL);
}
static int register_pm_qos_misc(struct pm_qos_object *qos)
}
/**
- * pm_qos_requirement - returns current system wide qos expectation
+ * pm_qos_request - 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 pm_qos_request(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;
+ return atomic_read(&pm_qos_array[pm_qos_class]->target_value);
}
-EXPORT_SYMBOL_GPL(pm_qos_requirement);
+EXPORT_SYMBOL_GPL(pm_qos_request);
/**
- * pm_qos_add_requirement - inserts new qos request into the list
+ * pm_qos_add_request - 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 characteristics. It recomputes the aggregate QoS expectations
- * for the pm_qos_class of parameters.
+ * for the pm_qos_class of parameters, and returns the pm_qos_request list
+ * element as a handle for use in updating and removal. Call needs to save
+ * this handle for later use.
*/
-int pm_qos_add_requirement(int pm_qos_class, char *name, s32 value)
+struct pm_qos_request_list *pm_qos_add_request(int pm_qos_class, s32 value)
{
- struct requirement_list *dep;
+ struct pm_qos_request_list *dep;
unsigned long flags;
- dep = kzalloc(sizeof(struct requirement_list), GFP_KERNEL);
+ dep = kzalloc(sizeof(struct pm_qos_request_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;
+ dep->pm_qos_class = pm_qos_class;
spin_lock_irqsave(&pm_qos_lock, flags);
list_add(&dep->list,
- &pm_qos_array[pm_qos_class]->requirements.list);
+ &pm_qos_array[pm_qos_class]->requests.list);
spin_unlock_irqrestore(&pm_qos_lock, flags);
update_target(pm_qos_class);
-
- return 0;
}
-cleanup:
- kfree(dep);
- return -ENOMEM;
+ return dep;
}
-EXPORT_SYMBOL_GPL(pm_qos_add_requirement);
+EXPORT_SYMBOL_GPL(pm_qos_add_request);
/**
- * pm_qos_update_requirement - modifies an existing qos request
- * @pm_qos_class: identifies which list of qos request to us
- * @name: identifies the request
+ * pm_qos_update_request - modifies an existing qos request
+ * @pm_qos_req : handle to list element holding a pm_qos request to use
* @value: defines the qos request
*
- * Updates an existing qos requirement for the pm_qos_class of parameters along
+ * Updates an existing qos request for the pm_qos_class of parameters along
* with updating the target pm_qos_class value.
*
- * If the named request isn't in the list then no change is made.
+ * Attempts are made to make this code callable on hot code paths.
*/
-int pm_qos_update_requirement(int pm_qos_class, char *name, s32 new_value)
+void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req,
+ s32 new_value)
{
unsigned long flags;
- struct requirement_list *node;
int pending_update = 0;
+ s32 temp;
- 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;
+ if (pm_qos_req) { /*guard against callers passing in null */
+ spin_lock_irqsave(&pm_qos_lock, flags);
+ if (new_value == PM_QOS_DEFAULT_VALUE)
+ temp = pm_qos_array[pm_qos_req->pm_qos_class]->default_value;
+ else
+ temp = new_value;
+
+ if (temp != pm_qos_req->value) {
pending_update = 1;
- break;
+ pm_qos_req->value = temp;
}
+ spin_unlock_irqrestore(&pm_qos_lock, flags);
+ if (pending_update)
+ update_target(pm_qos_req->pm_qos_class);
}
- spin_unlock_irqrestore(&pm_qos_lock, flags);
- if (pending_update)
- update_target(pm_qos_class);
-
- return 0;
}
-EXPORT_SYMBOL_GPL(pm_qos_update_requirement);
+EXPORT_SYMBOL_GPL(pm_qos_update_request);
/**
- * pm_qos_remove_requirement - modifies an existing qos request
- * @pm_qos_class: identifies which list of qos request to us
- * @name: identifies the request
+ * pm_qos_remove_request - modifies an existing qos request
+ * @pm_qos_req: handle to request list element
*
- * Will remove named qos request from pm_qos_class list of parameters and
- * recompute the current target value for the pm_qos_class.
+ * Will remove pm qos request from the list of requests and
+ * recompute the current target value for the pm_qos_class. Call this
+ * on slow code paths.
*/
-void pm_qos_remove_requirement(int pm_qos_class, char *name)
+void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req)
{
unsigned long flags;
- struct requirement_list *node;
- int pending_update = 0;
+ int qos_class;
+ if (pm_qos_req == NULL)
+ return;
+ /* silent return to keep pcm code cleaner */
+
+ qos_class = pm_qos_req->pm_qos_class;
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;
- }
- }
+ list_del(&pm_qos_req->list);
+ kfree(pm_qos_req);
spin_unlock_irqrestore(&pm_qos_lock, flags);
- if (pending_update)
- update_target(pm_qos_class);
+ update_target(qos_class);
}
-EXPORT_SYMBOL_GPL(pm_qos_remove_requirement);
+EXPORT_SYMBOL_GPL(pm_qos_remove_request);
/**
* pm_qos_add_notifier - sets notification entry for changes to target value
* will register the notifier into a notification chain that gets called
* upon changes to the pm_qos_class target value.
*/
- int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
+int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
{
int 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;
long pm_qos_class;
- lock_kernel();
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) {
- unlock_kernel();
+ filp->private_data = (void *) pm_qos_add_request(pm_qos_class,
+ PM_QOS_DEFAULT_VALUE);
+
+ if (filp->private_data)
return 0;
- }
}
- unlock_kernel();
-
return -EPERM;
}
static int pm_qos_power_release(struct inode *inode, struct file *filp)
{
- int pm_qos_class;
+ struct pm_qos_request_list *req;
- pm_qos_class = (long)filp->private_data;
- sprintf(name, "process_%d", current->pid);
- pm_qos_remove_requirement(pm_qos_class, name);
+ req = (struct pm_qos_request_list *)filp->private_data;
+ pm_qos_remove_request(req);
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 = (long)filp->private_data;
- if (count != sizeof(s32))
+ int x;
+ char ascii_value[11];
+ struct pm_qos_request_list *pm_qos_req;
+
+ if (count == sizeof(s32)) {
+ if (copy_from_user(&value, buf, sizeof(s32)))
+ return -EFAULT;
+ } else if (count == 11) { /* len('0x12345678/0') */
+ if (copy_from_user(ascii_value, buf, 11))
+ return -EFAULT;
+ x = sscanf(ascii_value, "%x", &value);
+ if (x != 1)
+ return -EINVAL;
+ pr_debug(KERN_ERR "%s, %d, 0x%x\n", ascii_value, x, value);
+ } else
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);
+ pm_qos_req = (struct pm_qos_request_list *)filp->private_data;
+ pm_qos_update_request(pm_qos_req, value);
+
+ return count;
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff