Patch "sched/uclamp: Cater for uclamp in find_energy_efficient_cpu()'s early exit condition" has been added to the 6.1-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    sched/uclamp: Cater for uclamp in find_energy_efficient_cpu()'s early exit condition

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     sched-uclamp-cater-for-uclamp-in-find_energy_efficie.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 4a7bb54d8f0099bdd583ea98ace01f8616a09e20
Author: Qais Yousef <qais.yousef@xxxxxxx>
Date:   Thu Aug 4 15:36:07 2022 +0100

    sched/uclamp: Cater for uclamp in find_energy_efficient_cpu()'s early exit condition
    
    [ Upstream commit d81304bc6193554014d4372a01debdf65e1e9a4d ]
    
    If the utilization of the woken up task is 0, we skip the energy
    calculation because it has no impact.
    
    But if the task is boosted (uclamp_min != 0) will have an impact on task
    placement and frequency selection. Only skip if the util is truly
    0 after applying uclamp values.
    
    Change uclamp_task_cpu() signature to avoid unnecessary additional calls
    to uclamp_eff_get(). feec() is the only user now.
    
    Fixes: 732cd75b8c920 ("sched/fair: Select an energy-efficient CPU on task wake-up")
    Signed-off-by: Qais Yousef <qais.yousef@xxxxxxx>
    Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/20220804143609.515789-8-qais.yousef@xxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index a0ee3192e5a7..0f32acb05055 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4280,14 +4280,16 @@ static inline unsigned long task_util_est(struct task_struct *p)
 }
 
 #ifdef CONFIG_UCLAMP_TASK
-static inline unsigned long uclamp_task_util(struct task_struct *p)
+static inline unsigned long uclamp_task_util(struct task_struct *p,
+					     unsigned long uclamp_min,
+					     unsigned long uclamp_max)
 {
-	return clamp(task_util_est(p),
-		     uclamp_eff_value(p, UCLAMP_MIN),
-		     uclamp_eff_value(p, UCLAMP_MAX));
+	return clamp(task_util_est(p), uclamp_min, uclamp_max);
 }
 #else
-static inline unsigned long uclamp_task_util(struct task_struct *p)
+static inline unsigned long uclamp_task_util(struct task_struct *p,
+					     unsigned long uclamp_min,
+					     unsigned long uclamp_max)
 {
 	return task_util_est(p);
 }
@@ -7205,7 +7207,7 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu)
 	target = prev_cpu;
 
 	sync_entity_load_avg(&p->se);
-	if (!task_util_est(p))
+	if (!uclamp_task_util(p, p_util_min, p_util_max))
 		goto unlock;
 
 	eenv_task_busy_time(&eenv, p, prev_cpu);