summaryrefslogtreecommitdiff
path: root/drivers/cpuidle
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/cpuidle')
-rw-r--r--drivers/cpuidle/governors/menu.c28
1 files changed, 17 insertions, 11 deletions
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index a8b31b0ca57f..cf7f2f0e4ef5 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -123,10 +123,10 @@ struct menu_device {
int needs_update;
unsigned int expected_us;
- u64 predicted_us;
+ unsigned int predicted_us;
unsigned int exit_us;
unsigned int bucket;
- u64 correction_factor[BUCKETS];
+ unsigned int correction_factor[BUCKETS];
unsigned int intervals[INTERVALS];
int interval_ptr;
};
@@ -321,8 +321,13 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
if (data->correction_factor[data->bucket] == 0)
data->correction_factor[data->bucket] = RESOLUTION * DECAY;
- /* Make sure to round up for half microseconds */
- data->predicted_us = div_round64(data->expected_us * data->correction_factor[data->bucket],
+ /*
+ * Force the result of multiplication to be 64 bits even if both
+ * operands are 32 bits.
+ * Make sure to round up for half microseconds.
+ */
+ data->predicted_us = div_round64((uint64_t)data->expected_us *
+ data->correction_factor[data->bucket],
RESOLUTION * DECAY);
get_typical_interval(data);
@@ -388,7 +393,7 @@ static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
unsigned int last_idle_us = cpuidle_get_last_residency(dev);
struct cpuidle_state *target = &drv->states[last_idx];
unsigned int measured_us;
- u64 new_factor;
+ unsigned int new_factor;
/*
* Ugh, this idle state doesn't support residency measurements, so we
@@ -409,10 +414,9 @@ static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
measured_us -= data->exit_us;
- /* update our correction ratio */
-
- new_factor = data->correction_factor[data->bucket]
- * (DECAY - 1) / DECAY;
+ /* Update our correction ratio */
+ new_factor = data->correction_factor[data->bucket];
+ new_factor -= new_factor / DECAY;
if (data->expected_us > 0 && measured_us < MAX_INTERESTING)
new_factor += RESOLUTION * measured_us / data->expected_us;
@@ -425,9 +429,11 @@ static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
/*
* We don't want 0 as factor; we always want at least
- * a tiny bit of estimated time.
+ * 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 (new_factor == 0)
+ if (DECAY == 1 && unlikely(new_factor == 0))
new_factor = 1;
data->correction_factor[data->bucket] = new_factor;