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Date: Thu, 30 Jan 2014 15:09:20 +0100
From: Daniel Lezcano <daniel.lezcano@...aro.org>
To: nicolas.pitre@...aro.org, peterz@...radead.org, mingo@...hat.com,
tglx@...utronix.de, rjw@...ysocki.net
Cc: linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
linaro-kernel@...ts.linaro.org
Subject: [RFC PATCH 1/3] cpuidle: split cpuidle_idle_call main function into functions
In order to allow better integration between the cpuidle framework and the
scheduler, reducing the distance between the sub-component helps.
This patch splits the cpuidle_idle_call main entry function into 3 big chunks
of API:
1. select the idle state
2. enter the idle state
3. reflect the idle state
The cpuidle_idle_call now calls these three functions to implement the main
idle entry function.
Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
---
drivers/cpuidle/cpuidle.c | 105 ++++++++++++++++++++++++++++++++-------------
include/linux/cpuidle.h | 7 +++
2 files changed, 83 insertions(+), 29 deletions(-)
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index a55e68f..a8fbb28 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -108,6 +108,74 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
}
/**
+ * cpuidle_select - ask the cpuidle framework to choose an idle state
+ *
+ * @drv: the cpuidle driver
+ * @dev: the cpuidle device
+ *
+ * Returns the index of the idle state. On error it returns:
+ * -NODEV : the cpuidle framework is available
+ * -EBUSY : the cpuidle framework is not initialized
+ */
+int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
+{
+ if (off || !initialized)
+ return -ENODEV;
+
+ if (!drv || !dev || !dev->enabled)
+ return -EBUSY;
+
+ return cpuidle_curr_governor->select(drv, dev);
+}
+EXPORT_SYMBOL(cpuidle_select);
+
+/**
+ * cpuidle_enter - enter into the specified idle state
+ *
+ * @drv: the cpuidle driver tied with the cpu
+ * @dev: the cpuidle device
+ * @index: the index in the idle state table
+ *
+ * Returns the index in the idle state, < 0 in case of error.
+ * The error code depends on the backend driver
+ */
+int cpuidle_enter(struct cpuidle_driver *drv, struct cpuidle_device *dev,
+ int index)
+{
+ int entered_state;
+ bool broadcast = !!(drv->states[index].flags & CPUIDLE_FLAG_TIMER_STOP);
+
+ if (broadcast)
+ clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &dev->cpu);
+
+ if (cpuidle_state_is_coupled(dev, drv, index))
+ entered_state = cpuidle_enter_state_coupled(dev, drv, index);
+ else
+ entered_state = cpuidle_enter_state(dev, drv, index);
+
+ if (broadcast)
+ clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &dev->cpu);
+
+ return entered_state;
+}
+EXPORT_SYMBOL(cpuidle_enter);
+
+/**
+ * cpuidle_reflect - tell the underlying governor what was the state
+ * we were in
+ *
+ * @dev : the cpuidle device
+ * @index: the index in the idle state table
+ *
+ */
+void cpuidle_reflect(struct cpuidle_device *dev, int index)
+{
+ if (cpuidle_curr_governor->reflect)
+ cpuidle_curr_governor->reflect(dev, index);
+}
+EXPORT_SYMBOL(cpuidle_reflect);
+
+/**
* cpuidle_idle_call - the main idle loop
*
* NOTE: no locks or semaphores should be used here
@@ -116,51 +184,30 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
int cpuidle_idle_call(void)
{
struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
- struct cpuidle_driver *drv;
+ struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
int next_state, entered_state;
- bool broadcast;
-
- if (off || !initialized)
- return -ENODEV;
-
- /* check if the device is ready */
- if (!dev || !dev->enabled)
- return -EBUSY;
-
- drv = cpuidle_get_cpu_driver(dev);
/* ask the governor for the next state */
- next_state = cpuidle_curr_governor->select(drv, dev);
+ next_state = cpuidle_select(drv, dev);
+ if (next_state < 0)
+ return next_state;
+
if (need_resched()) {
dev->last_residency = 0;
/* give the governor an opportunity to reflect on the outcome */
- if (cpuidle_curr_governor->reflect)
- cpuidle_curr_governor->reflect(dev, next_state);
+ cpuidle_reflect(dev, next_state);
local_irq_enable();
return 0;
}
trace_cpu_idle_rcuidle(next_state, dev->cpu);
- broadcast = !!(drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP);
-
- if (broadcast)
- clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &dev->cpu);
-
- if (cpuidle_state_is_coupled(dev, drv, next_state))
- entered_state = cpuidle_enter_state_coupled(dev, drv,
- next_state);
- else
- entered_state = cpuidle_enter_state(dev, drv, next_state);
-
- if (broadcast)
- clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &dev->cpu);
+ entered_state = cpuidle_enter(drv, dev, next_state);
trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
/* give the governor an opportunity to reflect on the outcome */
- if (cpuidle_curr_governor->reflect)
- cpuidle_curr_governor->reflect(dev, entered_state);
+ cpuidle_reflect(dev, entered_state);
return 0;
}
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index 50fcbb0..1ebe9ff 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -119,6 +119,13 @@ struct cpuidle_driver {
#ifdef CONFIG_CPU_IDLE
extern void disable_cpuidle(void);
+
+extern int cpuidle_select(struct cpuidle_driver *drv,
+ struct cpuidle_device *dev);
+extern int cpuidle_enter(struct cpuidle_driver *drv,
+ struct cpuidle_device *dev, int index);
+extern void cpuidle_reflect(struct cpuidle_device *dev, int index);
+
extern int cpuidle_idle_call(void);
extern int cpuidle_register_driver(struct cpuidle_driver *drv);
extern struct cpuidle_driver *cpuidle_get_driver(void);
--
1.7.9.5
--
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