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 6.0-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-6.0 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 700e30bf88cc442b6115310d89fcd749082fadd5 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 2e782d79e80f..532e6cdf706d 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4108,14 +4108,16 @@ 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); } @@ -7029,7 +7031,7 @@ 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);