Hello Shrikanth,
On 8/29/2025 2:23 PM, Shrikanth Hegde wrote:
> I was looking at:
> https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/log/?h=sched/core
>
> Current code doesn't allow one to enable/disable SCHED_MC on ppc since it is
> set always in kconfig.
> Used the below patch:
>
> I think since the config is there, it would be good to provide a option to
> disable. no?
I think this makes sense.
FWIW, Peter added the "select SCHED_MC" to keep it consistent with the
current behavior.
>
> ---
>
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index fc0d1c19f5a1..da5b2f8d3686 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -170,9 +170,8 @@ config PPC
> select ARCH_STACKWALK
> select ARCH_SUPPORTS_ATOMIC_RMW
> select ARCH_SUPPORTS_DEBUG_PAGEALLOC if PPC_BOOK3S || PPC_8xx
> - select ARCH_SUPPORTS_SCHED_SMT if PPC64 && SMP
> select ARCH_SUPPORTS_SCHED_MC if PPC64 && SMP
> - select SCHED_MC if ARCH_SUPPORTS_SCHED_MC
> + select ARCH_SUPPORTS_SCHED_SMT if PPC64 && SMP
> select ARCH_USE_BUILTIN_BSWAP
> select ARCH_USE_CMPXCHG_LOCKREF if PPC64
> select ARCH_USE_MEMTEST
> diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
> index 68edb66c2964..458ec5bd859e 100644
> --- a/arch/powerpc/kernel/smp.c
> +++ b/arch/powerpc/kernel/smp.c
> @@ -1706,10 +1706,12 @@ static void __init build_sched_topology(void)
> SDTL_INIT(tl_cache_mask, powerpc_shared_cache_flags, CACHE);
> }
>
> +#ifdef CONFIG_SCHED_MC
> if (has_coregroup_support()) {
> powerpc_topology[i++] =
> SDTL_INIT(tl_mc_mask, powerpc_shared_proc_flags, MC);
> }
> +#endif
When I was looking at this, the whole of .*coregroup.* related bits in
smp.c can technically go behind CONFIG_SCHED_MC too but that is a much
larger cleanup and perhaps unnecessary too so this looks good.
--
Thanks and Regards,
Prateek
