[PATCH 2/2] cpuidle: Respect latency constraints when accounting below misses

[Christian Loehle]

Only count a below miss when an enabled deeper state meets the latency
constraint. Save the applicable limit before entry so QoS changes during
idle do not affect accounting. Continue checking disable flags on exit.

Fixes: 04dab58a39d4 ("cpuidle: Add 'above' and 'below' idle state metrics")
Signed-off-by: Christian Loehle <christian.loehle@xxxxxxx>
---
 drivers/cpuidle/cpuidle.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index faa29f58738e..e9195ea8cfb6 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -219,6 +219,7 @@ noinstr int cpuidle_enter_state(struct cpuidle_device *dev,
 				 int index)
 {
 	int entered_state;
+	s64 latency_req;
 
 	struct cpuidle_state *target_state = &drv->states[index];
 	bool broadcast = !!(target_state->flags & CPUIDLE_FLAG_TIMER_STOP);
@@ -244,6 +245,8 @@ noinstr int cpuidle_enter_state(struct cpuidle_device *dev,
 	if (target_state->flags & CPUIDLE_FLAG_TLB_FLUSHED)
 		leave_mm();
 
+	latency_req = cpuidle_governor_latency_req(dev->cpu);
+
 	/* Take note of the planned idle state. */
 	sched_idle_set_state(target_state);
 
@@ -327,7 +330,8 @@ noinstr int cpuidle_enter_state(struct cpuidle_device *dev,
 			}
 		} else if (diff > delay) {
 			for (i = entered_state + 1; i < drv->state_count; i++) {
-				if (dev->states_usage[i].disable)
+				if (dev->states_usage[i].disable ||
+				    drv->states[i].exit_latency_ns > latency_req)
 					continue;
 
 				/*
-- 
2.34.1