Re: [RFC PATCH v2 2/3] sched: Introduce cpus_share_l2c

[Aaron Lu]

On Sat, Aug 19, 2023 at 08:31:55AM -0400, Mathieu Desnoyers wrote:
> +#ifdef TOPOLOGY_CLUSTER_SYSFS
> +static int cpu_get_l2c_info(int cpu, int *l2c_size, int *l2c_id)
> +{
> +	const struct cpumask *cluster_mask = topology_cluster_cpumask(cpu);
> +
> +	*l2c_size = cpumask_weight(cluster_mask);
> +	*l2c_id = cpumask_first(cluster_mask);
> +	return 0;
> +}
> +#else
> +static int cpu_get_l2c_info(int cpu, int *l2c_size, int *l2c_id)
> +{
> +	return -1;
> +}
> +#endif
> +
>  static void update_top_cache_domain(int cpu)
>  {
>  	struct sched_domain_shared *sds = NULL;
>  	struct sched_domain *sd;
> -	int id = cpu;
> -	int size = 1;
> +	int id = cpu, size = 1, l2c_id, l2c_size;
>  
>  	sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES);
>  	if (sd) {
> @@ -686,6 +704,14 @@ static void update_top_cache_domain(int cpu)
>  		sds = sd->shared;
>  	}
>  
> +	if (cpu_get_l2c_info(cpu, &l2c_id, &l2c_size)) {

Should be:  cpu_get_l2c_info(cpu, &l2c_size, &l2c_id)

> +		/* Fallback on using LLC. */
> +		l2c_size = size;
> +		l2c_id = id;
> +	}
> +	per_cpu(sd_l2c_size, cpu) = l2c_size;
> +	per_cpu(sd_l2c_id, cpu) = l2c_id;
> +
>  	rcu_assign_pointer(per_cpu(sd_llc, cpu), sd);
>  	per_cpu(sd_llc_size, cpu) = size;
>  	per_cpu(sd_llc_id, cpu) = id;
> -- 
> 2.39.2
>