linux-kernel - [PATCH 1/3] thermal/cpu-cooling, sched/core: Cleanup thermal pressure definition

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Message-Id: <20200614010755.9129-2-valentin.schneider@arm.com>
Date:   Sun, 14 Jun 2020 02:07:53 +0100
From:   Valentin Schneider <valentin.schneider@....com>
To:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-pm@...r.kernel.org
Cc:     Russell King <linux@...linux.org.uk>,
        Thara Gopinath <thara.gopinath@...aro.org>,
        Sudeep Holla <sudeep.holla@....com>,
        Amit Daniel Kachhap <amit.kachhap@...il.com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>
Subject: [PATCH 1/3] thermal/cpu-cooling, sched/core: Cleanup thermal pressure definition

The following commit:

  14533a16c46d ("thermal/cpu-cooling, sched/core: Move the arch_set_thermal_pressure() API to generic scheduler code")

moved the definition of arch_set_thermal_pressure() to sched/core.c, but
kept its declaration in linux/arch_topology.h. When building e.g. an x86
kernel with CONFIG_SCHED_THERMAL_PRESSURE=y, cpufreq_cooling.c ends up
getting the declaration of arch_set_thermal_pressure() from
include/linux/arch_topology.h, which is somewhat awkward.

On top of this, the public setter, arch_set_thermal_pressure(), is defined
unconditionally in sched/core.c while the public getter,
arch_scale_thermal_pressure(), is hardcoded to return 0 unless it has been
redefined by the architecture. arch_*() functions are meant to be defined
by architectures, so revert the aforementioned commit and re-implement it
in a way that keeps arch_set_thermal_pressure() architecture-definable.

Signed-off-by: Valentin Schneider <valentin.schneider@....com>
---
 drivers/base/arch_topology.c      | 11 +++++++++++
 drivers/thermal/cpufreq_cooling.c |  5 +++++
 include/linux/arch_topology.h     |  3 ---
 kernel/sched/core.c               | 11 -----------
 4 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
index 4d0a0038b476..d14cab7dfa3c 100644
--- a/drivers/base/arch_topology.c
+++ b/drivers/base/arch_topology.c
@@ -54,6 +54,17 @@ void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity)
 	per_cpu(cpu_scale, cpu) = capacity;
 }
 
+DEFINE_PER_CPU(unsigned long, thermal_pressure);
+
+void arch_set_thermal_pressure(const struct cpumask *cpus,
+			       unsigned long th_pressure)
+{
+	int cpu;
+
+	for_each_cpu(cpu, cpus)
+		WRITE_ONCE(per_cpu(thermal_pressure, cpu), th_pressure);
+}
+
 static ssize_t cpu_capacity_show(struct device *dev,
 				 struct device_attribute *attr,
 				 char *buf)
diff --git a/drivers/thermal/cpufreq_cooling.c b/drivers/thermal/cpufreq_cooling.c
index e297e135c031..a1efd379b683 100644
--- a/drivers/thermal/cpufreq_cooling.c
+++ b/drivers/thermal/cpufreq_cooling.c
@@ -417,6 +417,11 @@ static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev,
 	return 0;
 }
 
+__weak void
+arch_set_thermal_pressure(const struct cpumask *cpus, unsigned long th_pressure)
+{
+}
+
 /**
  * cpufreq_set_cur_state - callback function to set the current cooling state.
  * @cdev: thermal cooling device pointer.
diff --git a/include/linux/arch_topology.h b/include/linux/arch_topology.h
index 0566cb3314ef..81bd1c627195 100644
--- a/include/linux/arch_topology.h
+++ b/include/linux/arch_topology.h
@@ -39,9 +39,6 @@ static inline unsigned long topology_get_thermal_pressure(int cpu)
 	return per_cpu(thermal_pressure, cpu);
 }
 
-void arch_set_thermal_pressure(struct cpumask *cpus,
-			       unsigned long th_pressure);
-
 struct cpu_topology {
 	int thread_id;
 	int core_id;
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 43ba2d4a8eca..7861d21f3c2b 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3628,17 +3628,6 @@ unsigned long long task_sched_runtime(struct task_struct *p)
 	return ns;
 }
 
-DEFINE_PER_CPU(unsigned long, thermal_pressure);
-
-void arch_set_thermal_pressure(struct cpumask *cpus,
-			       unsigned long th_pressure)
-{
-	int cpu;
-
-	for_each_cpu(cpu, cpus)
-		WRITE_ONCE(per_cpu(thermal_pressure, cpu), th_pressure);
-}
-
 /*
  * This function gets called by the timer code, with HZ frequency.
  * We call it with interrupts disabled.
-- 
2.27.0