On 28/07/2020 18:16, Valentin Schneider wrote:

Hi,

On 27/07/20 18:45, Dietmar Eggemann wrote:

quoted

On 27/07/2020 16:18, Qian Cai wrote:

quoted

On Sun, Jul 12, 2020 at 05:59:16PM +0100, Valentin Schneider wrote:

[...]

I went for having SCHED_THERMAL_PRESSURE in arm64/Kconfig because of where
the discussion went in the original thread ([1] in the changelog).

One point is that selecting this option requires having the right
infrastructure in place (arch_{set, scale}_thermal_pressure() must be
redefined by the architecture), which cannot be easily expressed in Kconfig
terms. Russell's point was that this is difficult for a lambda user to make
sense of, and Vincent argued that this option should simply be selected at
architecture level, which, given the context, makes sense IMO.

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?

The warning when disabling CPU_FREQ_THERMAL after make defconfig disappears, so
this should be OK.

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 939c4d6bbc2e..a677e71b3d5f 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig

@@ -46,7 +46,7 @@ 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 SCHED_THERMAL_PRESSURE if ARM_CPU_TOPOLOGY && CPU_FREQ_THERMAL
        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..59ae16f8b941 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig

@@ -192,7 +192,7 @@ config ARM64
        select PCI_SYSCALL if PCI
        select POWER_RESET
        select POWER_SUPPLY
-       select SCHED_THERMAL_PRESSURE
+       select SCHED_THERMAL_PRESSURE if CPU_FREQ_THERMAL
        select SPARSE_IRQ
        select SWIOTLB
        select SYSCTL_EXCEPTION_TRAC

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