linux-kernel - Re: [PATCH v2 2/3] sched: Cleanup SCHED_THERMAL

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Date:   Wed, 29 Jul 2020 14:09:10 +0100
From:   Quentin Perret <qperret@...gle.com>
To:     Valentin Schneider <valentin.schneider@....com>
Cc:     Dietmar Eggemann <dietmar.eggemann@....com>, Qian Cai <cai@....pw>,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-pm@...r.kernel.org, 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>
Subject: Re: [PATCH v2 2/3] sched: Cleanup SCHED_THERMAL_PRESSURE kconfig
 entry

On Tuesday 28 Jul 2020 at 17:16:57 (+0100), Valentin Schneider wrote:
> We could change the arch Kconfig into
> 
>   select SCHED_THERMAL_PRESSURE if CPU_FREQ_THERMAL
> 
> but that seems redundant; this dependency is already expressed in
> SCHED_THERMAL_PRESSURE's definition. Is there a proper pattern to select
> some Kconfig option only if all of its dependencies are met?

How about something like this (totally untested):

---8<---
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 939c4d6bbc2e..2ac74904a3ce 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -46,7 +46,6 @@ config ARM
 	select EDAC_ATOMIC_SCRUB
 	select GENERIC_ALLOCATOR
 	select GENERIC_ARCH_TOPOLOGY if ARM_CPU_TOPOLOGY
-	select SCHED_THERMAL_PRESSURE if ARM_CPU_TOPOLOGY
 	select GENERIC_ATOMIC64 if CPU_V7M || CPU_V6 || !CPU_32v6K || !AEABI
 	select GENERIC_CLOCKEVENTS_BROADCAST if SMP
 	select GENERIC_CPU_AUTOPROBE
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index c403e6f5db86..66dc41fd49f2 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -192,7 +192,6 @@ config ARM64
 	select PCI_SYSCALL if PCI
 	select POWER_RESET
 	select POWER_SUPPLY
-	select SCHED_THERMAL_PRESSURE
 	select SPARSE_IRQ
 	select SWIOTLB
 	select SYSCTL_EXCEPTION_TRACE
diff --git a/init/Kconfig b/init/Kconfig
index 0a97d85568b2..c2e1f3ac527e 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -493,6 +493,7 @@ config HAVE_SCHED_AVG_IRQ
 
 config SCHED_THERMAL_PRESSURE
 	bool
+	default y if ARM64 || ARM_CPU_TOPOLOGY
 	depends on SMP
 	depends on CPU_FREQ_THERMAL
 	help
--->8---

Thanks,
Quentin