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Merge branch 'pm-cpuidle'

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Merge a menu governor fix for 6.17-rc3

* pm-cpuidle:
  cpuidle: governors: menu: Avoid selecting states with too much latency
This commit is contained in:
Rafael J. Wysocki
2025-08-21 20:32:25 +02:00
parent 2bc1adb05e 779b1a1cb1
commit 094a7c318b
1 changed files with 12 additions and 17 deletions
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29
drivers/cpuidle/governors/menu.c
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@@ -287,20 +287,15 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
return 0;
}
if (tick_nohz_tick_stopped()) {
/*
* If the tick is already stopped, the cost of possible short
* idle duration misprediction is much higher, because the CPU
* may be stuck in a shallow idle state for a long time as a
* result of it. In that case say we might mispredict and use
* the known time till the closest timer event for the idle
* state selection.
*/
if (predicted_ns < TICK_NSEC)
predicted_ns = data->next_timer_ns;
} else if (latency_req > predicted_ns) {
latency_req = predicted_ns;
}
/*
* If the tick is already stopped, the cost of possible short idle
* duration misprediction is much higher, because the CPU may be stuck
* in a shallow idle state for a long time as a result of it. In that
* case, say we might mispredict and use the known time till the closest
* timer event for the idle state selection.
*/
if (tick_nohz_tick_stopped() && predicted_ns < TICK_NSEC)
predicted_ns = data->next_timer_ns;
/*
* Find the idle state with the lowest power while satisfying
@@ -316,13 +311,15 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
if (idx == -1)
idx = i; /* first enabled state */
if (s->exit_latency_ns > latency_req)
break;
if (s->target_residency_ns > predicted_ns) {
/*
* Use a physical idle state, not busy polling, unless
* a timer is going to trigger soon enough.
*/
if ((drv->states[idx].flags & CPUIDLE_FLAG_POLLING) &&
s->exit_latency_ns <= latency_req &&
s->target_residency_ns <= data->next_timer_ns) {
predicted_ns = s->target_residency_ns;
idx = i;
@@ -354,8 +351,6 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
return idx;
}
if (s->exit_latency_ns > latency_req)
break;
idx = i;
}