linux-kernel - [PATCH 5/7] sched/uclamp: Make asym_fits_capacity() use util_fits

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Date:   Wed, 29 Jun 2022 20:46:30 +0100
From:   Qais Yousef <qais.yousef@....com>
To:     Ingo Molnar <mingo@...nel.org>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>
Cc:     linux-kernel@...r.kernel.org, Xuewen Yan <xuewen.yan94@...il.com>,
        Wei Wang <wvw@...gle.com>,
        Jonathan JMChen <Jonathan.JMChen@...iatek.com>,
        Hank <han.lin@...iatek.com>, Qais Yousef <qais.yousef@....com>
Subject: [PATCH 5/7] sched/uclamp: Make asym_fits_capacity() use util_fits_cpu()

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.

s/asym_fits_capacity/asym_fits_cpu/ to better reflect what it does now.

Fixes: b4c9c9f15649 ("sched/fair: Prefer prev cpu in asymmetric wakeup path")
Signed-off-by: Qais Yousef <qais.yousef@....com>
---
 kernel/sched/fair.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index db1fc6c1aa87..2cfb4efecbc2 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6567,10 +6567,13 @@ select_idle_capacity(struct task_struct *p, struct sched_domain *sd, int target)
 	return best_cpu;
 }
 
-static inline bool asym_fits_capacity(unsigned long task_util, int cpu)
+static inline bool asym_fits_cpu(unsigned long util,
+				 unsigned long util_min,
+				 unsigned long util_max,
+				 int cpu)
 {
 	if (static_branch_unlikely(&sched_asym_cpucapacity))
-		return fits_capacity(task_util, capacity_of(cpu));
+		return util_fits_cpu(util, util_min, util_max, cpu);
 
 	return true;
 }
@@ -6582,7 +6585,7 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
 {
 	bool has_idle_core = false;
 	struct sched_domain *sd;
-	unsigned long task_util;
+	unsigned long task_util, util_min, util_max;
 	int i, recent_used_cpu;
 
 	/*
@@ -6591,7 +6594,9 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
 	 */
 	if (static_branch_unlikely(&sched_asym_cpucapacity)) {
 		sync_entity_load_avg(&p->se);
-		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);
 	}
 
 	/*
@@ -6600,7 +6605,7 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
 	lockdep_assert_irqs_disabled();
 
 	if ((available_idle_cpu(target) || sched_idle_cpu(target)) &&
-	    asym_fits_capacity(task_util, target))
+	    asym_fits_cpu(task_util, util_min, util_max, target))
 		return target;
 
 	/*
@@ -6608,7 +6613,7 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
 	 */
 	if (prev != target && cpus_share_cache(prev, target) &&
 	    (available_idle_cpu(prev) || sched_idle_cpu(prev)) &&
-	    asym_fits_capacity(task_util, prev))
+	    asym_fits_cpu(task_util, util_min, util_max, prev))
 		return prev;
 
 	/*
@@ -6623,7 +6628,7 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
 	    in_task() &&
 	    prev == smp_processor_id() &&
 	    this_rq()->nr_running <= 1 &&
-	    asym_fits_capacity(task_util, prev)) {
+	    asym_fits_cpu(task_util, util_min, util_max, prev)) {
 		return prev;
 	}
 
@@ -6635,7 +6640,7 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
 	    cpus_share_cache(recent_used_cpu, target) &&
 	    (available_idle_cpu(recent_used_cpu) || sched_idle_cpu(recent_used_cpu)) &&
 	    cpumask_test_cpu(p->recent_used_cpu, p->cpus_ptr) &&
-	    asym_fits_capacity(task_util, recent_used_cpu)) {
+	    asym_fits_cpu(task_util, util_min, util_max, recent_used_cpu)) {
 		return recent_used_cpu;
 	}
 
-- 
2.25.1