From: Qais Yousef qais.yousef@arm.com
commit d81304bc6193554014d4372a01debdf65e1e9a4d upstream.
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@arm.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Link: https://lore.kernel.org/r/20220804143609.515789-8-qais.yousef@arm.com (cherry picked from commit d81304bc6193554014d4372a01debdf65e1e9a4d) Signed-off-by: Qais Yousef (Google) qyousef@layalina.io Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/sched/fair.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-)
--- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -3974,14 +3974,16 @@ static inline unsigned long task_util_es }
#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); } @@ -7014,7 +7016,7 @@ static int find_energy_efficient_cpu(str 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;
for (; pd; pd = pd->next) {