diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/cpuidle/governors/menu.c | 28 |
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; |