Re: [PATCH RESEND 0/3] Represent cluster topology and enable load balance between clusters

[Valentin Schneider]

On 05/10/21 09:50, Peter Zijlstra wrote:
> On Fri, Oct 01, 2021 at 04:22:46PM -0700, Tim Chen wrote:
>> On Fri, 2021-10-01 at 16:57 +0200, Peter Zijlstra wrote:
>
>> > The one questino I have is, do we want default y?
>>
>> I also agree that default y is preferable.
>
> I'll change at least the x86 one to:
>
>       default y
>       depends on SMP
>

Huh, so the arm64 SCHED_{SMT,MC} configs are defaultless (I added SCHED_SMT
to arm64's defconfig not so long ago), but x86 has them default y, which
I'm thinking is a tad better, and would be nice to harmonize. Unfortunately
different architectures have their own dependency requirements - arm has
ARM_CPU_TOPOLOGY, parisc has PARISC_CPU_TOPOLOGY...

Would you hate making SCHED_* a "generic" config, with a common default and
help text, and punt the arch specific stuff to an ARCH_SUPPORTS_* knob?

Something like:

arch/arm/Kconfig:
  select ARCH_SUPPORTS_SCHED_MC if ARM_CPU_TOPOLOGY

init/Kconfig:
  config SCHED_MC
    def_bool y
    depends on ARCH_SUPPORTS_SCHED_MC && SMP