[PATCH V3 6/6] cpuidle: menu: Move the update function before its declaration

Daniel Lezcano
2014-11-07T14:32:03Z

In order to prevent a pointless forward declaration, just move the function
at the beginning of the file.

This patch does not change the behavior of the governor, it is just code
reordering.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Len Brown <len.brown@intel.com>
---
drivers/cpuidle/governors/menu.c | 149 +++++++++++++++++++--------------------
1 file changed, 74 insertions(+), 75 deletions(-)

diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index 163e63b..b8017ad 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -184,7 +184,6 @@ static inline int performance_multiplier(unsigned long nr_iowaiters, unsigned lo

static DEFINE_PER_CPU(struct menu_device, menu_devices);

-static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev);

/* This implements DIV_ROUND_CLOSEST but avoids 64 bit division */
static u64 div_round64(u64 dividend, u32 divisor)
@@ -192,6 +191,80 @@ static u64 div_round64(u64 dividend, u32 divisor)
return div_u64(dividend + (divisor / 2), divisor);
}

+/**
+ * menu_update - attempts to guess what happened after entry
+ * @drv: cpuidle driver containing state data
+ * @dev: the CPU
+ */
+static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
+{
+ struct menu_device *data = this_cpu_ptr(&menu_devices);
+ int last_idx = data->last_state_idx;
+ struct cpuidle_state *target = &drv->states[last_idx];
+ unsigned int measured_us;
+ unsigned int new_factor;
+
+ /*
+ * Try to figure out how much time passed between entry to low
+ * power state and occurrence of the wakeup event.
+ *
+ * If the entered idle state didn't support residency measurements,
+ * we are basically lost in the dark how much time passed.
+ * As a compromise, assume we slept for the whole expected time.
+ *
+ * Any measured amount of time will include the exit latency.
+ * Since we are interested in when the wakeup begun, not when it
+ * was completed, we must subtract the exit latency. However, if
+ * the measured amount of time is less than the exit latency,
+ * assume the state was never reached and the exit latency is 0.
+ */
+ if (unlikely(!(target->flags & CPUIDLE_FLAG_TIME_VALID))) {
+ /* Use timer value as is */
+ measured_us = data->next_timer_us;
+
+ } else {
+ /* Use measured value */
+ measured_us = cpuidle_get_last_residency(dev);
+
+ /* Deduct exit latency */
+ if (measured_us > target->exit_latency)
+ measured_us -= target->exit_latency;
+
+ /* Make sure our coefficients do not exceed unity */
+ if (measured_us > data->next_timer_us)
+ measured_us = data->next_timer_us;
+ }
+
+ /* Update our correction ratio */
+ new_factor = data->correction_factor[data->bucket];
+ new_factor -= new_factor / DECAY;
+
+ if (data->next_timer_us > 0 && measured_us < MAX_INTERESTING)
+ new_factor += RESOLUTION * measured_us / data->next_timer_us;
+ else
+ /*
+ * we were idle so long that we count it as a perfect
+ * prediction
+ */
+ new_factor += RESOLUTION;
+
+ /*
+ * We don't want 0 as factor; we always want at least
+ * a tiny bit of estimated time. Fortunately, due to rounding,
+ * new_factor will stay nonzero regardless of measured_us values
+ * and the compiler can eliminate this test as long as DECAY > 1.
+ */
+ if (DECAY == 1 && unlikely(new_factor == 0))
+ new_factor = 1;
+
+ data->correction_factor[data->bucket] = new_factor;
+
+ /* update the repeating-pattern data */
+ data->intervals[data->interval_ptr++] = measured_us;
+ if (data->interval_ptr >= INTERVALS)
+ data->interval_ptr = 0;
+}
+
/*
* Try detecting repeating patterns by keeping track of the last 8
* intervals, and checking if the standard deviation of that set
@@ -371,80 +444,6 @@ static void menu_reflect(struct cpuidle_device *dev, int index)
}

/**
- * menu_update - attempts to guess what happened after entry
- * @drv: cpuidle driver containing state data
- * @dev: the CPU
- */
-static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
-{
- struct menu_device *data = this_cpu_ptr(&menu_devices);
- int last_idx = data->last_state_idx;
- struct cpuidle_state *target = &drv->states[last_idx];
- unsigned int measured_us;
- unsigned int new_factor;
-
- /*
- * Try to figure out how much time passed between entry to low
- * power state and occurrence of the wakeup event.
- *
- * If the entered idle state didn't support residency measurements,
- * we are basically lost in the dark how much time passed.
- * As a compromise, assume we slept for the whole expected time.
- *
- * Any measured amount of time will include the exit latency.
- * Since we are interested in when the wakeup begun, not when it
- * was completed, we must subtract the exit latency. However, if
- * the measured amount of time is less than the exit latency,
- * assume the state was never reached and the exit latency is 0.
- */
- if (unlikely(!(target->flags & CPUIDLE_FLAG_TIME_VALID))) {
- /* Use timer value as is */
- measured_us = data->next_timer_us;
-
- } else {
- /* Use measured value */
- measured_us = cpuidle_get_last_residency(dev);
-
- /* Deduct exit latency */
- if (measured_us > target->exit_latency)
- measured_us -= target->exit_latency;
-
- /* Make sure our coefficients do not exceed unity */
- if (measured_us > data->next_timer_us)
- measured_us = data->next_timer_us;
- }
-
- /* Update our correction ratio */
- new_factor = data->correction_factor[data->bucket];
- new_factor -= new_factor / DECAY;
-
- if (data->next_timer_us > 0 && measured_us < MAX_INTERESTING)
- new_factor += RESOLUTION * measured_us / data->next_timer_us;
- else
- /*
- * we were idle so long that we count it as a perfect
- * prediction
- */
- new_factor += RESOLUTION;
-
- /*
- * We don't want 0 as factor; we always want at least
- * a tiny bit of estimated time. Fortunately, due to rounding,
- * new_factor will stay nonzero regardless of measured_us values
- * and the compiler can eliminate this test as long as DECAY > 1.
- */
- if (DECAY == 1 && unlikely(new_factor == 0))
- new_factor = 1;
-
- data->correction_factor[data->bucket] = new_factor;
-
- /* update the repeating-pattern data */
- data->intervals[data->interval_ptr++] = measured_us;
- if (data->interval_ptr >= INTERVALS)
- data->interval_ptr = 0;
-}
-
-/**
* menu_enable_device - scans a CPU's states and does setup
* @drv: cpuidle driver
* @dev: the CPU
--
1.9.1