Re: [PATCH v3 3/8] sched/topology: Switch to assigning "sd->shared" from s_data

[Valentin Schneider]

On 20/01/26 11:32, K Prateek Nayak wrote:
> @@ -2655,8 +2655,19 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att
>               unsigned int imb_span = 1;
>
>               for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
> +			struct sched_domain *parent = sd->parent;
>                       struct sched_domain *child = sd->child;
>
> +			/* Attach sd->shared to the topmost SD_SHARE_LLC domain. */
> +			if ((sd->flags & SD_SHARE_LLC) &&
> +			    (!parent || !(parent->flags & SD_SHARE_LLC))) {
> +				int llc_id = cpumask_first(sched_domain_span(sd));
> +
> +				sd->shared = *per_cpu_ptr(d.sds, llc_id);
> +				atomic_set(&sd->shared->nr_busy_cpus, sd->span_weight);
> +				atomic_inc(&sd->shared->ref);
> +			}
> +

We now have two if's looking for the highest_flag_domain(i, SD_SHARE_LLC),
but given this needs to write the sd->imb_numa_nr for every SD I couldn't
factorize this into something that looked sane :(

>                       if (!(sd->flags & SD_SHARE_LLC) && child &&
>                           (child->flags & SD_SHARE_LLC)) {
>                               struct sched_domain __rcu *top_p;