diff options
| -rw-r--r-- | include/linux/pm_qos_params.h | 4 | ||||
| -rw-r--r-- | kernel/pm_qos_params.c | 37 |
2 files changed, 29 insertions, 12 deletions
diff --git a/include/linux/pm_qos_params.h b/include/linux/pm_qos_params.h index 77cbddb3784c..a7d87f911cab 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 aeaa7f846821..6a8fad82a3ad 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); |