linux-kernel - [PATCH v8 3/4] sched/topology: Remove max_cpu_capacity from root

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Message-Id: <20240324004552.999936-4-qyousef@layalina.io>
Date: Sun, 24 Mar 2024 00:45:51 +0000
From: Qais Yousef <qyousef@...alina.io>
To: Ingo Molnar <mingo@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Dietmar Eggemann <dietmar.eggemann@....com>
Cc: linux-kernel@...r.kernel.org,
	"Pierre Gondois" <Pierre.Gondois@....com>,
	Qais Yousef <qyousef@...alina.io>
Subject: [PATCH v8 3/4] sched/topology: Remove max_cpu_capacity from root_domain

The value is no longer used as we now keep track of max_allowed_capacity
for each task instead.

Reviewed-by: Vincent Guittot <vincent.guittot@...aro.org>
Signed-off-by: Qais Yousef <qyousef@...alina.io>
---
 kernel/sched/sched.h    |  2 --
 kernel/sched/topology.c | 13 ++-----------
 2 files changed, 2 insertions(+), 13 deletions(-)

diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index f77c00dddfe1..4f9e952d4fad 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -917,8 +917,6 @@ struct root_domain {
 	cpumask_var_t		rto_mask;
 	struct cpupri		cpupri;
 
-	unsigned long		max_cpu_capacity;
-
 	/*
 	 * NULL-terminated list of performance domains intersecting with the
 	 * CPUs of the rd. Protected by RCU.
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 44ed3d0812ab..63aecd2a7a9f 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -2514,16 +2514,9 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att
 	/* Attach the domains */
 	rcu_read_lock();
 	for_each_cpu(i, cpu_map) {
-		unsigned long capacity;
-
 		rq = cpu_rq(i);
 		sd = *per_cpu_ptr(d.sd, i);
 
-		capacity = arch_scale_cpu_capacity(i);
-		/* Use READ_ONCE()/WRITE_ONCE() to avoid load/store tearing: */
-		if (capacity > READ_ONCE(d.rd->max_cpu_capacity))
-			WRITE_ONCE(d.rd->max_cpu_capacity, capacity);
-
 		cpu_attach_domain(sd, d.rd, i);
 
 		if (lowest_flag_domain(i, SD_CLUSTER))
@@ -2537,10 +2530,8 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att
 	if (has_cluster)
 		static_branch_inc_cpuslocked(&sched_cluster_active);
 
-	if (rq && sched_debug_verbose) {
-		pr_info("root domain span: %*pbl (max cpu_capacity = %lu)\n",
-			cpumask_pr_args(cpu_map), rq->rd->max_cpu_capacity);
-	}
+	if (rq && sched_debug_verbose)
+		pr_info("root domain span: %*pbl\n", cpumask_pr_args(cpu_map));
 
 	ret = 0;
 error:
-- 
2.34.1