[PATCH 6/6] cpuidle: menu: Move the latency_req == 0 special case check

Rafael J. Wysocki
2018-10-02T21:47:43Z

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

It is better to always update data->bucket before returning from
menu_select() so as to prevent disturbing the wakeup statistics
collected by the governor, so combine the latency_req == 0 special
check with the more general check below.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/cpuidle/governors/menu.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)

Index: linux-pm/drivers/cpuidle/governors/menu.c
===================================================================
--- linux-pm.orig/drivers/cpuidle/governors/menu.c
+++ linux-pm/drivers/cpuidle/governors/menu.c
@@ -297,19 +297,13 @@ static int menu_select(struct cpuidle_dr
data->needs_update = 0;
}

- /* Special case when user has set very strict latency requirement */
- if (unlikely(latency_req == 0)) {
- *stop_tick = false;
- return 0;
- }
-
/* determine the expected residency time, round up */
data->next_timer_us = ktime_to_us(tick_nohz_get_sleep_length(&delta_next));

get_iowait_load(&nr_iowaiters, &cpu_load);
data->bucket = which_bucket(data->next_timer_us, nr_iowaiters);

- if (unlikely(drv->state_count <= 1) ||
+ if (unlikely(drv->state_count <= 1 || latency_req == 0) ||
((data->next_timer_us < drv->states[1].target_residency ||
latency_req < drv->states[1].exit_latency) &&
!drv->states[0].disabled && !dev->states_usage[0].disable)) {