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authorLinus Torvalds <torvalds@linux-foundation.org>2011-05-29 11:18:09 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-05-29 11:18:09 -0700
commitf310642123e0d32d919c60ca3fab5acd130c4ba3 (patch)
treef3844152e2e8c0fdd01621a400f84c8a159252a0 /kernel/pm_qos_params.c
parentef1d57599dc904fdb31b8e9b5336350d21a1fde1 (diff)
parent5d4c47e0195b989f284907358bd5c268a44b91c7 (diff)
Merge branch 'idle-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6
* 'idle-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6: x86 idle: deprecate mwait_idle() and "idle=mwait" cmdline param x86 idle: deprecate "no-hlt" cmdline param x86 idle APM: deprecate CONFIG_APM_CPU_IDLE x86 idle floppy: deprecate disable_hlt() x86 idle: EXPORT_SYMBOL(default_idle, pm_idle) only when APM demands it x86 idle: clarify AMD erratum 400 workaround idle governor: Avoid lock acquisition to read pm_qos before entering idle cpuidle: menu: fixed wrapping timers at 4.294 seconds
Diffstat (limited to 'kernel/pm_qos_params.c')
-rw-r--r--kernel/pm_qos_params.c37
1 files changed, 25 insertions, 12 deletions
diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c
index fd8d1e035df..6824ca7d4d0 100644
--- a/kernel/pm_qos_params.c
+++ b/kernel/pm_qos_params.c
@@ -54,11 +54,17 @@ 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;
};
@@ -71,7 +77,8 @@ 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,
};
@@ -80,7 +87,8 @@ 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
};
@@ -90,7 +98,8 @@ 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,
};
@@ -136,6 +145,16 @@ 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)
{
@@ -160,6 +179,7 @@ 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)
@@ -194,18 +214,11 @@ 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);