Re: [PATCH v4] powerpc/smp: Use nid as fallback for package_id

[Gautham R Shenoy <ego@linux.vnet.ibm.com>]

Hello Srikar,



On Wed, Jan 29, 2020 at 07:21:21PM +0530, Srikar Dronamraju wrote:

[..snip..]

> --- a/arch/powerpc/kernel/smp.c
> +++ b/arch/powerpc/kernel/smp.c
> @@ -1185,10 +1185,34 @@ static inline void add_cpu_to_smallcore_masks(int cpu)
>  	}
>  }
> 
> +int get_physical_package_id(int cpu)
> +{
> +	int ppid = cpu_to_chip_id(cpu);
> +
> +#ifdef CONFIG_PPC_SPLPAR
> +	/*
> +	 * If the platform is PowerNV or Guest on KVM, ibm,chip-id is
> +	 * defined. Hence we would return the chip-id as the
> +	 * get_physical_package_id.
> +	 */
> +	if (ppid == -1 && firmware_has_feature(FW_FEATURE_LPAR)) {
> +		struct device_node *np = of_get_cpu_node(cpu, NULL);
> +
> +		if (np) {
> +			ppid = of_node_to_nid(np);
> +			of_node_put(np);
> +		}
> +	}
> +#endif /* CONFIG_PPC_SPLPAR */
> +
> +	return ppid;
> +}
> +EXPORT_SYMBOL_GPL(get_physical_package_id);
> +
>  static void add_cpu_to_masks(int cpu)
>  {
>  	int first_thread = cpu_first_thread_sibling(cpu);
> -	int chipid = cpu_to_chip_id(cpu);
> +	int ppid = get_physical_package_id(cpu);
>  	int i;
> 
>  	/*
> @@ -1217,11 +1241,11 @@ static void add_cpu_to_masks(int cpu)
>  	for_each_cpu(i, cpu_l2_cache_mask(cpu))
>  		set_cpus_related(cpu, i, cpu_core_mask);
> 
> -	if (chipid == -1)
> +	if (ppid == -1)
>  		return;

Can get_physical_package_id() return -1 ?

> 
>  	for_each_cpu(i, cpu_online_mask)
> -		if (cpu_to_chip_id(i) == chipid)
> +		if (get_physical_package_id(i) == ppid)
>  			set_cpus_related(cpu, i, cpu_core_mask);
>  }
> 
> -- 
> 2.18.1
>

--
Thanks and Regards
gautham.