mirror of https://gitee.com/openkylin/linux.git
pm_qos: Reimplement using plists
A lot of the pm_qos extremal value handling is really duplicating what a priority ordered list does, just in a less efficient fashion. Simply redoing the implementation in terms of a plist gets rid of a lot of this junk (although there are several other strange things that could do with tidying up, like pm_qos_request_list has to carry the pm_qos_class with every node, simply because it doesn't get passed in to pm_qos_update_request even though every caller knows full well what parameter it's updating). I think this redo is a win independent of android, so we should do something like this now. Signed-off-by: James Bottomley <James.Bottomley@suse.de> Signed-off-by: mark gross <markgross@thegnar.org> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
This commit is contained in:
James Bottomley
Rafael J. Wysocki
parent
12e4d0cc2e
commit
5f279845f9
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@ -30,6 +30,7 @@
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/*#define DEBUG*/
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#include <linux/pm_qos_params.h>
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#include <linux/plist.h>
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#include <linux/sched.h>
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#include <linux/spinlock.h>
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#include <linux/slab.h>
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@ -49,58 +50,53 @@
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* held, taken with _irqsave. One lock to rule them all
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*/
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struct pm_qos_request_list {
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struct list_head list;
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union {
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s32 value;
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s32 usec;
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s32 kbps;
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};
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struct plist_node list;
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int pm_qos_class;
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};
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static s32 max_compare(s32 v1, s32 v2);
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static s32 min_compare(s32 v1, s32 v2);
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enum pm_qos_type {
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PM_QOS_MAX, /* return the largest value */
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PM_QOS_MIN /* return the smallest value */
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};
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struct pm_qos_object {
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struct pm_qos_request_list requests;
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struct plist_head requests;
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struct blocking_notifier_head *notifiers;
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struct miscdevice pm_qos_power_miscdev;
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char *name;
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s32 default_value;
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atomic_t target_value;
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s32 (*comparitor)(s32, s32);
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enum pm_qos_type type;
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};
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static DEFINE_SPINLOCK(pm_qos_lock);
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static struct pm_qos_object null_pm_qos;
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static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier);
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static struct pm_qos_object cpu_dma_pm_qos = {
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.requests = {LIST_HEAD_INIT(cpu_dma_pm_qos.requests.list)},
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.requests = PLIST_HEAD_INIT(cpu_dma_pm_qos.requests, pm_qos_lock),
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.notifiers = &cpu_dma_lat_notifier,
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.name = "cpu_dma_latency",
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.default_value = 2000 * USEC_PER_SEC,
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.target_value = ATOMIC_INIT(2000 * USEC_PER_SEC),
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.comparitor = min_compare
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.type = PM_QOS_MIN,
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};
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static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);
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static struct pm_qos_object network_lat_pm_qos = {
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.requests = {LIST_HEAD_INIT(network_lat_pm_qos.requests.list)},
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.requests = PLIST_HEAD_INIT(network_lat_pm_qos.requests, pm_qos_lock),
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.notifiers = &network_lat_notifier,
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.name = "network_latency",
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.default_value = 2000 * USEC_PER_SEC,
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.target_value = ATOMIC_INIT(2000 * USEC_PER_SEC),
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.comparitor = min_compare
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.type = PM_QOS_MIN
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};
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static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier);
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static struct pm_qos_object network_throughput_pm_qos = {
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.requests = {LIST_HEAD_INIT(network_throughput_pm_qos.requests.list)},
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.requests = PLIST_HEAD_INIT(network_throughput_pm_qos.requests, pm_qos_lock),
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.notifiers = &network_throughput_notifier,
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.name = "network_throughput",
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.default_value = 0,
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.target_value = ATOMIC_INIT(0),
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.comparitor = max_compare
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.type = PM_QOS_MAX,
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};
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@ -111,8 +107,6 @@ static struct pm_qos_object *pm_qos_array[] = {
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&network_throughput_pm_qos
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};
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static DEFINE_SPINLOCK(pm_qos_lock);
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static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
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size_t count, loff_t *f_pos);
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static int pm_qos_power_open(struct inode *inode, struct file *filp);
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@ -124,46 +118,55 @@ static const struct file_operations pm_qos_power_fops = {
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.release = pm_qos_power_release,
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};
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/* static helper functions */
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static s32 max_compare(s32 v1, s32 v2)
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/* unlocked internal variant */
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static inline int pm_qos_get_value(struct pm_qos_object *o)
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{
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return max(v1, v2);
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if (plist_head_empty(&o->requests))
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return o->default_value;
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switch (o->type) {
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case PM_QOS_MIN:
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return plist_last(&o->requests)->prio;
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case PM_QOS_MAX:
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return plist_first(&o->requests)->prio;
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default:
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/* runtime check for not using enum */
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BUG();
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}
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}
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static s32 min_compare(s32 v1, s32 v2)
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static void update_target(struct pm_qos_object *o, struct plist_node *node,
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int del, int value)
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{
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return min(v1, v2);
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}
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static void update_target(int pm_qos_class)
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{
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s32 extreme_value;
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struct pm_qos_request_list *node;
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unsigned long flags;
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int call_notifier = 0;
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int prev_value, curr_value;
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spin_lock_irqsave(&pm_qos_lock, flags);
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extreme_value = pm_qos_array[pm_qos_class]->default_value;
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list_for_each_entry(node,
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&pm_qos_array[pm_qos_class]->requests.list, list) {
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extreme_value = pm_qos_array[pm_qos_class]->comparitor(
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extreme_value, node->value);
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}
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if (atomic_read(&pm_qos_array[pm_qos_class]->target_value) !=
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extreme_value) {
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call_notifier = 1;
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atomic_set(&pm_qos_array[pm_qos_class]->target_value,
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extreme_value);
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pr_debug(KERN_ERR "new target for qos %d is %d\n", pm_qos_class,
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atomic_read(&pm_qos_array[pm_qos_class]->target_value));
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prev_value = pm_qos_get_value(o);
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/* PM_QOS_DEFAULT_VALUE is a signal that the value is unchanged */
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if (value != PM_QOS_DEFAULT_VALUE) {
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/*
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* to change the list, we atomically remove, reinit
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* with new value and add, then see if the extremal
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* changed
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*/
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plist_del(node, &o->requests);
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plist_node_init(node, value);
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plist_add(node, &o->requests);
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} else if (del) {
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plist_del(node, &o->requests);
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} else {
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plist_add(node, &o->requests);
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}
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curr_value = pm_qos_get_value(o);
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spin_unlock_irqrestore(&pm_qos_lock, flags);
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if (call_notifier)
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blocking_notifier_call_chain(
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pm_qos_array[pm_qos_class]->notifiers,
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(unsigned long) extreme_value, NULL);
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if (prev_value != curr_value)
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blocking_notifier_call_chain(o->notifiers,
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(unsigned long)curr_value,
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NULL);
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}
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static int register_pm_qos_misc(struct pm_qos_object *qos)
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@ -196,7 +199,14 @@ static int find_pm_qos_object_by_minor(int minor)
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*/
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int pm_qos_request(int pm_qos_class)
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{
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return atomic_read(&pm_qos_array[pm_qos_class]->target_value);
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unsigned long flags;
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int value;
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spin_lock_irqsave(&pm_qos_lock, flags);
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value = pm_qos_get_value(pm_qos_array[pm_qos_class]);
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spin_unlock_irqrestore(&pm_qos_lock, flags);
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return value;
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}
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EXPORT_SYMBOL_GPL(pm_qos_request);
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@ -214,21 +224,19 @@ EXPORT_SYMBOL_GPL(pm_qos_request);
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struct pm_qos_request_list *pm_qos_add_request(int pm_qos_class, s32 value)
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{
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struct pm_qos_request_list *dep;
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unsigned long flags;
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dep = kzalloc(sizeof(struct pm_qos_request_list), GFP_KERNEL);
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if (dep) {
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if (value == PM_QOS_DEFAULT_VALUE)
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dep->value = pm_qos_array[pm_qos_class]->default_value;
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else
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dep->value = value;
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dep->pm_qos_class = pm_qos_class;
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struct pm_qos_object *o = pm_qos_array[pm_qos_class];
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int new_value;
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spin_lock_irqsave(&pm_qos_lock, flags);
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list_add(&dep->list,
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&pm_qos_array[pm_qos_class]->requests.list);
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spin_unlock_irqrestore(&pm_qos_lock, flags);
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update_target(pm_qos_class);
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if (value == PM_QOS_DEFAULT_VALUE)
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new_value = o->default_value;
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else
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new_value = value;
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plist_node_init(&dep->list, new_value);
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dep->pm_qos_class = pm_qos_class;
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update_target(o, &dep->list, 0, PM_QOS_DEFAULT_VALUE);
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}
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return dep;
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@ -246,27 +254,23 @@ EXPORT_SYMBOL_GPL(pm_qos_add_request);
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* Attempts are made to make this code callable on hot code paths.
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*/
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void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req,
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s32 new_value)
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s32 new_value)
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{
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unsigned long flags;
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int pending_update = 0;
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s32 temp;
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struct pm_qos_object *o;
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if (pm_qos_req) { /*guard against callers passing in null */
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spin_lock_irqsave(&pm_qos_lock, flags);
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if (new_value == PM_QOS_DEFAULT_VALUE)
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temp = pm_qos_array[pm_qos_req->pm_qos_class]->default_value;
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else
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temp = new_value;
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if (!pm_qos_req) /*guard against callers passing in null */
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return;
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if (temp != pm_qos_req->value) {
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pending_update = 1;
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pm_qos_req->value = temp;
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}
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spin_unlock_irqrestore(&pm_qos_lock, flags);
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if (pending_update)
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update_target(pm_qos_req->pm_qos_class);
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}
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o = pm_qos_array[pm_qos_req->pm_qos_class];
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if (new_value == PM_QOS_DEFAULT_VALUE)
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temp = o->default_value;
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else
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temp = new_value;
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if (temp != pm_qos_req->list.prio)
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update_target(o, &pm_qos_req->list, 0, temp);
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}
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EXPORT_SYMBOL_GPL(pm_qos_update_request);
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@ -280,19 +284,15 @@ EXPORT_SYMBOL_GPL(pm_qos_update_request);
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*/
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void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req)
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{
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unsigned long flags;
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int qos_class;
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struct pm_qos_object *o;
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if (pm_qos_req == NULL)
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return;
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/* silent return to keep pcm code cleaner */
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qos_class = pm_qos_req->pm_qos_class;
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spin_lock_irqsave(&pm_qos_lock, flags);
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list_del(&pm_qos_req->list);
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o = pm_qos_array[pm_qos_req->pm_qos_class];
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update_target(o, &pm_qos_req->list, 1, PM_QOS_DEFAULT_VALUE);
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kfree(pm_qos_req);
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spin_unlock_irqrestore(&pm_qos_lock, flags);
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update_target(qos_class);
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}
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EXPORT_SYMBOL_GPL(pm_qos_remove_request);
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