[PATCH 6.1 0109/1146] sched/uclamp: Make select_idle_capacity() use util_fits_cpu()

Greg Kroah-Hartman
2022-12-28T15:12:07Z

From: Qais Yousef <qais.yousef@arm.com>

[ Upstream commit b759caa1d9f667b94727b2ad12589cbc4ce13a82 ]

Use the new util_fits_cpu() to ensure migration margin and capacity
pressure are taken into account correctly when uclamp is being used
otherwise we will fail to consider CPUs as fitting in scenarios where
they should.

Fixes: b4c9c9f15649 ("sched/fair: Prefer prev cpu in asymmetric wakeup path")
Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220804143609.515789-5-qais.yousef@arm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/sched/fair.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c8eb5ff81084..c877bbfe5deb 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6779,21 +6779,23 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool
static int
select_idle_capacity(struct task_struct *p, struct sched_domain *sd, int target)
{
- unsigned long task_util, best_cap = 0;
+ unsigned long task_util, util_min, util_max, best_cap = 0;
int cpu, best_cpu = -1;
struct cpumask *cpus;

cpus = this_cpu_cpumask_var_ptr(select_rq_mask);
cpumask_and(cpus, sched_domain_span(sd), p->cpus_ptr);

- task_util = uclamp_task_util(p);
+ task_util = task_util_est(p);
+ util_min = uclamp_eff_value(p, UCLAMP_MIN);
+ util_max = uclamp_eff_value(p, UCLAMP_MAX);

for_each_cpu_wrap(cpu, cpus, target) {
unsigned long cpu_cap = capacity_of(cpu);

if (!available_idle_cpu(cpu) && !sched_idle_cpu(cpu))
continue;
- if (fits_capacity(task_util, cpu_cap))
+ if (util_fits_cpu(task_util, util_min, util_max, cpu))
return cpu;

if (cpu_cap > best_cap) {
--
2.35.1