This allows for atomic notifications.
This may be necessary to have in some future scenarios,
as it eliminates any scheduling between update_request and doing the
notifier_callback.
---
I took the naming of the interface functions James Bottomly suggested in an earlier patch.
include/linux/pm_qos_params.h | 1 +
kernel/pm_qos_params.c | 76 ++++++++++++++++++++++++++++++++---------
2 files changed, 61 insertions(+), 16 deletions(-)
diff --git a/include/linux/pm_qos_params.h b/include/linux/pm_qos_params.h
index 8ba440e..0f41378 100644
--- a/include/linux/pm_qos_params.h
+++ b/include/linux/pm_qos_params.h
@@ -23,5 +23,6 @@ void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req);
int pm_qos_request(int pm_qos_class);
int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier);
+int pm_qos_add_atomic_notifier(int pm_qos_class, struct notifier_block *notifier);
int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier);
diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c
index 296343a..9346906 100644
--- a/kernel/pm_qos_params.c
+++ b/kernel/pm_qos_params.c
@@ -65,7 +65,8 @@ static void update_notify(struct work_struct *work);
struct pm_qos_object {
struct pm_qos_request_list requests;
- struct blocking_notifier_head *notifiers;
+ struct blocking_notifier_head *blocking_notifiers;
+ struct atomic_notifier_head *atomic_notifiers;
struct miscdevice pm_qos_power_miscdev;
struct work_struct notify;
char *name;
@@ -76,21 +77,25 @@ struct pm_qos_object {
static struct pm_qos_object null_pm_qos;
-static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier);
+static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier_blocking);
+static ATOMIC_NOTIFIER_HEAD(cpu_dma_lat_notifier_atomic);
static struct pm_qos_object cpu_dma_pm_qos = {
.requests = {LIST_HEAD_INIT(cpu_dma_pm_qos.requests.list)},
- .notifiers = &cpu_dma_lat_notifier,
+ .blocking_notifiers = &cpu_dma_lat_notifier_blocking,
+ .atomic_notifiers = &cpu_dma_lat_notifier_atomic,
.notify = __WORK_INITIALIZER(cpu_dma_pm_qos.notify, update_notify),
.name = "cpu_dma_latency",
.default_value = 2000 * USEC_PER_SEC,
.target_value = ATOMIC_INIT(2000 * USEC_PER_SEC),
- .comparitor = min_compare
+ .comparitor = min_compare,
};
-static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);
+static BLOCKING_NOTIFIER_HEAD(network_lat_notifier_blocking);
+static ATOMIC_NOTIFIER_HEAD(network_lat_notifier_atomic);
static struct pm_qos_object network_lat_pm_qos = {
.requests = {LIST_HEAD_INIT(network_lat_pm_qos.requests.list)},
- .notifiers = &network_lat_notifier,
+ .blocking_notifiers = &network_lat_notifier_blocking,
+ .atomic_notifiers = &network_lat_notifier_atomic,
.notify = __WORK_INITIALIZER(network_lat_pm_qos.notify, update_notify),
.name = "network_latency",
.default_value = 2000 * USEC_PER_SEC,
@@ -99,10 +104,12 @@ static struct pm_qos_object network_lat_pm_qos = {
};
-static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier);
+static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier_blocking);
+static ATOMIC_NOTIFIER_HEAD(network_throughput_notifier_atomic);
static struct pm_qos_object network_throughput_pm_qos = {
.requests = {LIST_HEAD_INIT(network_throughput_pm_qos.requests.list)},
- .notifiers = &network_throughput_notifier,
+ .blocking_notifiers = &network_throughput_notifier_blocking,
+ .atomic_notifiers = &network_throughput_notifier_atomic,
.notify = __WORK_INITIALIZER(network_throughput_pm_qos.notify,
update_notify),
.name = "network_throughput",
@@ -142,6 +149,16 @@ static s32 min_compare(s32 v1, s32 v2)
return min(v1, v2);
}
+static void pm_qos_call_notifiers(struct pm_qos_object *o,
+ unsigned long curr_value)
+{
+ schedule_work(&o->notify);
+
+ if (o->atomic_notifiers)
+ atomic_notifier_call_chain(o->atomic_notifiers,
+ curr_value, NULL);
+}
+
static void update_notify(struct work_struct *work)
{
struct pm_qos_object *obj =
@@ -149,7 +166,7 @@ static void update_notify(struct work_struct *work)
s32 extreme_value = atomic_read(&obj->target_value);
blocking_notifier_call_chain(
- obj->notifiers,
+ obj->blocking_notifiers,
(unsigned long) extreme_value, NULL);
}
@@ -175,7 +192,7 @@ static void update_target(int pm_qos_class)
spin_unlock_irqrestore(&pm_qos_lock, flags);
if (call_notifier)
- schedule_work(&obj->notify);
+ pm_qos_call_notifiers(obj, extreme_value);
}
static int register_pm_qos_misc(struct pm_qos_object *qos)
@@ -310,24 +327,48 @@ EXPORT_SYMBOL_GPL(pm_qos_remove_request);
/**
* pm_qos_add_notifier - sets notification entry for changes to target value
- * @pm_qos_class: identifies which qos target changes should be notified.
+ * @pm_qos_class: identifies which qos target changes should trigger
+ * notifications.
* @notifier: notifier block managed by caller.
*
* 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 *nb)
{
int retval;
retval = blocking_notifier_chain_register(
- pm_qos_array[pm_qos_class]->notifiers, notifier);
+ pm_qos_array[pm_qos_class]->blocking_notifiers, nb);
return retval;
}
EXPORT_SYMBOL_GPL(pm_qos_add_notifier);
/**
+ * pm_qos_add_atomic_notifier - sets notification entry for changes to target value
+ * @pm_qos_class: identifies which qos target changes should trigger
+ * notifications.
+ * @notifier: notifier block managed by caller.
+ *
+ * Will register the notifier into a notification chain that gets
+ * called upon changes to the pm_qos_class target value. The notifier
+ * may be called from atomic context. use @pm_qos_remove_notifier to
+ * unregister.
+ *
+ */
+int pm_qos_add_atomic_notifier(int pm_qos_class, struct notifier_block *notifier)
+{
+ /* guard against programming error */
+ BUG_ON(!pm_qos_array[pm_qos_class]->atomic_notifiers);
+
+ return atomic_notifier_chain_register(
+ pm_qos_array[pm_qos_class]->atomic_notifiers,
+ notifier);
+}
+EXPORT_SYMBOL_GPL(pm_qos_add_atomic_notifier);
+
+/**
* pm_qos_remove_notifier - deletes notification entry from chain.
* @pm_qos_class: identifies which qos target changes are notified.
* @notifier: notifier block to be removed.
@@ -335,13 +376,16 @@ EXPORT_SYMBOL_GPL(pm_qos_add_notifier);
* Will remove the notifier from the notification chain that gets called
* upon changes to the pm_qos_class target value.
*/
-int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
+int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *nb)
{
int retval;
retval = blocking_notifier_chain_unregister(
- pm_qos_array[pm_qos_class]->notifiers, notifier);
-
+ pm_qos_array[pm_qos_class]->blocking_notifiers, nb);
+ if (retval) {
+ retval = atomic_notifier_chain_unregister(
+ pm_qos_array[pm_qos_class]->atomic_notifiers, nb);
+ }
return retval;
}
EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);
--
1.7.1
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