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authorJames Bottomley <James.Bottomley@suse.de>2010-07-19 02:00:18 +0200
committerRafael J. Wysocki <rjw@sisk.pl>2010-07-19 02:00:18 +0200
commit5f279845f9d684661563894d44729a0c706375b4 (patch)
treede26a630f8b573ccf725a48652700504d1088d8d /kernel
parent12e4d0cc2e0a776a526c93bb2fcb9267abc6e0b1 (diff)
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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/pm_qos_params.c172
1 files changed, 86 insertions, 86 deletions
diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c
index f42d3f737a33..db8e51d7f392 100644
--- a/kernel/pm_qos_params.c
+++ b/kernel/pm_qos_params.c
@@ -30,6 +30,7 @@
/*#define DEBUG*/
#include <linux/pm_qos_params.h>
+#include <linux/plist.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
@@ -49,58 +50,53 @@
* held, taken with _irqsave. One lock to rule them all
*/
struct pm_qos_request_list {
- struct list_head list;
- union {
- s32 value;
- s32 usec;
- s32 kbps;
- };
+ struct plist_node list;
int pm_qos_class;
};
-static s32 max_compare(s32 v1, s32 v2);
-static s32 min_compare(s32 v1, s32 v2);
+enum pm_qos_type {
+ PM_QOS_MAX, /* return the largest value */
+ PM_QOS_MIN /* return the smallest value */
+};
struct pm_qos_object {
- struct pm_qos_request_list requests;
+ struct plist_head requests;
struct blocking_notifier_head *notifiers;
struct miscdevice pm_qos_power_miscdev;
char *name;
s32 default_value;
- atomic_t target_value;
- s32 (*comparitor)(s32, s32);
+ enum pm_qos_type type;
};
+static DEFINE_SPINLOCK(pm_qos_lock);
+
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 = {
- .requests = {LIST_HEAD_INIT(cpu_dma_pm_qos.requests.list)},
+ .requests = PLIST_HEAD_INIT(cpu_dma_pm_qos.requests, pm_qos_lock),
.notifiers = &cpu_dma_lat_notifier,
.name = "cpu_dma_latency",
.default_value = 2000 * USEC_PER_SEC,
- .target_value = ATOMIC_INIT(2000 * USEC_PER_SEC),
- .comparitor = min_compare
+ .type = PM_QOS_MIN,
};
static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);
static struct pm_qos_object network_lat_pm_qos = {
- .requests = {LIST_HEAD_INIT(network_lat_pm_qos.requests.list)},
+ .requests = PLIST_HEAD_INIT(network_lat_pm_qos.requests, pm_qos_lock),
.notifiers = &network_lat_notifier,
.name = "network_latency",
.default_value = 2000 * USEC_PER_SEC,
- .target_value = ATOMIC_INIT(2000 * USEC_PER_SEC),
- .comparitor = min_compare
+ .type = PM_QOS_MIN
};
static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier);
static struct pm_qos_object network_throughput_pm_qos = {
- .requests = {LIST_HEAD_INIT(network_throughput_pm_qos.requests.list)},
+ .requests = PLIST_HEAD_INIT(network_throughput_pm_qos.requests, pm_qos_lock),
.notifiers = &network_throughput_notifier,
.name = "network_throughput",
.default_value = 0,
- .target_value = ATOMIC_INIT(0),
- .comparitor = max_compare
+ .type = PM_QOS_MAX,
};
@@ -111,8 +107,6 @@ static struct pm_qos_object *pm_qos_array[] = {
&network_throughput_pm_qos
};
-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);
@@ -124,46 +118,55 @@ static const struct file_operations pm_qos_power_fops = {
.release = pm_qos_power_release,
};
-/* static helper functions */
-static s32 max_compare(s32 v1, s32 v2)
+/* unlocked internal variant */
+static inline int pm_qos_get_value(struct pm_qos_object *o)
{
- return max(v1, v2);
-}
+ if (plist_head_empty(&o->requests))
+ return o->default_value;
-static s32 min_compare(s32 v1, s32 v2)
-{
- return min(v1, v2);
-}
+ switch (o->type) {
+ case PM_QOS_MIN:
+ return plist_last(&o->requests)->prio;
+ case PM_QOS_MAX:
+ return plist_first(&o->requests)->prio;
-static void update_target(int pm_qos_class)
+ default:
+ /* runtime check for not using enum */
+ BUG();
+ }
+}
+
+static void update_target(struct pm_qos_object *o, struct plist_node *node,
+ int del, int value)
{
- s32 extreme_value;
- struct pm_qos_request_list *node;
unsigned long flags;
- int call_notifier = 0;
+ int prev_value, curr_value;
spin_lock_irqsave(&pm_qos_lock, flags);
- extreme_value = pm_qos_array[pm_qos_class]->default_value;
- list_for_each_entry(node,
- &pm_qos_array[pm_qos_class]->requests.list, list) {
- extreme_value = pm_qos_array[pm_qos_class]->comparitor(
- extreme_value, node->value);
- }
- if (atomic_read(&pm_qos_array[pm_qos_class]->target_value) !=
- extreme_value) {
- call_notifier = 1;
- 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));
+ prev_value = pm_qos_get_value(o);
+ /* PM_QOS_DEFAULT_VALUE is a signal that the value is unchanged */
+ if (value != PM_QOS_DEFAULT_VALUE) {
+ /*
+ * to change the list, we atomically remove, reinit
+ * with new value and add, then see if the extremal
+ * changed
+ */
+ plist_del(node, &o->requests);
+ plist_node_init(node, value);
+ plist_add(node, &o->requests);
+ } else if (del) {
+ plist_del(node, &o->requests);
+ } else {
+ plist_add(node, &o->requests);
}
+ curr_value = pm_qos_get_value(o);
spin_unlock_irqrestore(&pm_qos_lock, flags);
- if (call_notifier)
- blocking_notifier_call_chain(
- pm_qos_array[pm_qos_class]->notifiers,
- (unsigned long) extreme_value, NULL);
+ if (prev_value != curr_value)
+ blocking_notifier_call_chain(o->notifiers,
+ (unsigned long)curr_value,
+ NULL);
}
static int register_pm_qos_misc(struct pm_qos_object *qos)
@@ -196,7 +199,14 @@ static int find_pm_qos_object_by_minor(int minor)
*/
int pm_qos_request(int pm_qos_class)
{
- return atomic_read(&pm_qos_array[pm_qos_class]->target_value);
+ unsigned long flags;
+ int value;
+
+ spin_lock_irqsave(&pm_qos_lock, flags);
+ value = pm_qos_get_value(pm_qos_array[pm_qos_class]);
+ spin_unlock_irqrestore(&pm_qos_lock, flags);
+
+ return value;
}
EXPORT_SYMBOL_GPL(pm_qos_request);
@@ -214,21 +224,19 @@ EXPORT_SYMBOL_GPL(pm_qos_request);
struct pm_qos_request_list *pm_qos_add_request(int pm_qos_class, s32 value)
{
struct pm_qos_request_list *dep;
- unsigned long flags;
dep = kzalloc(sizeof(struct pm_qos_request_list), GFP_KERNEL);
if (dep) {
+ struct pm_qos_object *o = pm_qos_array[pm_qos_class];
+ int new_value;
+
if (value == PM_QOS_DEFAULT_VALUE)
- dep->value = pm_qos_array[pm_qos_class]->default_value;
+ new_value = o->default_value;
else
- dep->value = value;
+ new_value = value;
+ plist_node_init(&dep->list, new_value);
dep->pm_qos_class = pm_qos_class;
-
- spin_lock_irqsave(&pm_qos_lock, flags);
- list_add(&dep->list,
- &pm_qos_array[pm_qos_class]->requests.list);
- spin_unlock_irqrestore(&pm_qos_lock, flags);
- update_target(pm_qos_class);
+ update_target(o, &dep->list, 0, PM_QOS_DEFAULT_VALUE);
}
return dep;
@@ -246,27 +254,23 @@ EXPORT_SYMBOL_GPL(pm_qos_add_request);
* Attempts are made to make this code callable on hot code paths.
*/
void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req,
- s32 new_value)
+ s32 new_value)
{
- unsigned long flags;
- int pending_update = 0;
s32 temp;
+ struct pm_qos_object *o;
- 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;
- pm_qos_req->value = temp;
- }
- spin_unlock_irqrestore(&pm_qos_lock, flags);
- if (pending_update)
- update_target(pm_qos_req->pm_qos_class);
- }
+ if (!pm_qos_req) /*guard against callers passing in null */
+ return;
+
+ o = pm_qos_array[pm_qos_req->pm_qos_class];
+
+ if (new_value == PM_QOS_DEFAULT_VALUE)
+ temp = o->default_value;
+ else
+ temp = new_value;
+
+ if (temp != pm_qos_req->list.prio)
+ update_target(o, &pm_qos_req->list, 0, temp);
}
EXPORT_SYMBOL_GPL(pm_qos_update_request);
@@ -280,19 +284,15 @@ EXPORT_SYMBOL_GPL(pm_qos_update_request);
*/
void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req)
{
- unsigned long flags;
- int qos_class;
+ struct pm_qos_object *o;
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_del(&pm_qos_req->list);
+ o = pm_qos_array[pm_qos_req->pm_qos_class];
+ update_target(o, &pm_qos_req->list, 1, PM_QOS_DEFAULT_VALUE);
kfree(pm_qos_req);
- spin_unlock_irqrestore(&pm_qos_lock, flags);
- update_target(qos_class);
}
EXPORT_SYMBOL_GPL(pm_qos_remove_request);