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-rw-r--r--include/linux/pm_qos_params.h4
-rw-r--r--kernel/pm_qos_params.c37
2 files changed, 29 insertions, 12 deletions
diff --git a/include/linux/pm_qos_params.h b/include/linux/pm_qos_params.h
index 77cbddb..a7d87f9 100644
--- a/include/linux/pm_qos_params.h
+++ b/include/linux/pm_qos_params.h
@@ -16,6 +16,10 @@
#define PM_QOS_NUM_CLASSES 4
#define PM_QOS_DEFAULT_VALUE -1
+#define PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE (2000 * USEC_PER_SEC)
+#define PM_QOS_NETWORK_LAT_DEFAULT_VALUE (2000 * USEC_PER_SEC)
+#define PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE 0
+
struct pm_qos_request_list {
struct plist_node list;
int pm_qos_class;
diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c
index aeaa7f8..6a8fad8 100644
--- a/kernel/pm_qos_params.c
+++ b/kernel/pm_qos_params.c
@@ -53,11 +53,17 @@ enum pm_qos_type {
PM_QOS_MIN /* return the smallest value */
};
+/*
+ * Note: The lockless read path depends on the CPU accessing
+ * target_value atomically. Atomic access is only guaranteed on all CPU
+ * types linux supports for 32 bit quantites
+ */
struct pm_qos_object {
struct plist_head requests;
struct blocking_notifier_head *notifiers;
struct miscdevice pm_qos_power_miscdev;
char *name;
+ s32 target_value; /* Do not change to 64 bit */
s32 default_value;
enum pm_qos_type type;
};
@@ -70,7 +76,8 @@ static struct pm_qos_object cpu_dma_pm_qos = {
.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 = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,
+ .default_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,
.type = PM_QOS_MIN,
};
@@ -79,7 +86,8 @@ static struct pm_qos_object network_lat_pm_qos = {
.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 = PM_QOS_NETWORK_LAT_DEFAULT_VALUE,
+ .default_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE,
.type = PM_QOS_MIN
};
@@ -89,7 +97,8 @@ static struct pm_qos_object network_throughput_pm_qos = {
.requests = PLIST_HEAD_INIT(network_throughput_pm_qos.requests, pm_qos_lock),
.notifiers = &network_throughput_notifier,
.name = "network_throughput",
- .default_value = 0,
+ .target_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE,
+ .default_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE,
.type = PM_QOS_MAX,
};
@@ -132,6 +141,16 @@ static inline int pm_qos_get_value(struct pm_qos_object *o)
}
}
+static inline s32 pm_qos_read_value(struct pm_qos_object *o)
+{
+ return o->target_value;
+}
+
+static inline void pm_qos_set_value(struct pm_qos_object *o, s32 value)
+{
+ o->target_value = value;
+}
+
static void update_target(struct pm_qos_object *o, struct plist_node *node,
int del, int value)
{
@@ -156,6 +175,7 @@ static void update_target(struct pm_qos_object *o, struct plist_node *node,
plist_add(node, &o->requests);
}
curr_value = pm_qos_get_value(o);
+ pm_qos_set_value(o, curr_value);
spin_unlock_irqrestore(&pm_qos_lock, flags);
if (prev_value != curr_value)
@@ -190,18 +210,11 @@ static int find_pm_qos_object_by_minor(int minor)
* 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.
+ * This function returns the current target value.
*/
int pm_qos_request(int pm_qos_class)
{
- 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;
+ return pm_qos_read_value(pm_qos_array[pm_qos_class]);
}
EXPORT_SYMBOL_GPL(pm_qos_request);
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