Re: [PATCH 05/19] sched/fair: Add LLC index mapping for CPUs

[Peter Zijlstra]

On Sat, Oct 11, 2025 at 11:24:42AM -0700, Tim Chen wrote:
> diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
> index 2675db980f70..4bd033060f1d 100644
> --- a/kernel/sched/topology.c
> +++ b/kernel/sched/topology.c
> @@ -659,6 +659,7 @@ static void destroy_sched_domains(struct sched_domain *sd)
>  DEFINE_PER_CPU(struct sched_domain __rcu *, sd_llc);
>  DEFINE_PER_CPU(int, sd_llc_size);
>  DEFINE_PER_CPU(int, sd_llc_id);
> +DEFINE_PER_CPU(int, sd_llc_idx);
>  DEFINE_PER_CPU(int, sd_share_id);
>  DEFINE_PER_CPU(struct sched_domain_shared __rcu *, sd_llc_shared);
>  DEFINE_PER_CPU(struct sched_domain __rcu *, sd_numa);

There is literally *ONE* user of sd_llc_id, cpus_share_cache(), surely
that can equally use sd_llc_idx?

That is to say, do we really need two numbers for this?