Subject: Re: [PATCH v7 6/6] powerpc/pseries: Consolidate form1 distance initialization into a helper

From: David Gibson <[email-masked]>
Date: Tue, 10 Aug 2021 12:44:42 +1000

On Mon, Aug 09, 2021 at 10:54:34AM +0530, Aneesh Kumar K.V wrote:
> Currently, we duplicate parsing code for ibm,associativity and
> ibm,associativity-lookup-arrays in the kernel. The associativity array provided
> by these device tree properties are very similar and hence can use
> a helper to parse the node id and numa distance details.
> 
> Signed-off-by: Aneesh Kumar K.V <[email-masked]>

Reviewed-by: David Gibson <[email-masked]>

Though I'd prefer to see these fixes folded in with the earlier patch.

> ---
>  arch/powerpc/mm/numa.c | 104 +++++++++++++++++++++++------------------
>  1 file changed, 58 insertions(+), 46 deletions(-)
> 
> diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
> index fffb3c40f595..e6d47fcba335 100644
> --- a/arch/powerpc/mm/numa.c
> +++ b/arch/powerpc/mm/numa.c
> @@ -171,26 +171,36 @@ static void unmap_cpu_from_node(unsigned long cpu)
>  }
>  #endif /* CONFIG_HOTPLUG_CPU || CONFIG_PPC_SPLPAR */
>  
> -/*
> - * Returns nid in the range [0..nr_node_ids], or -1 if no useful NUMA
> - * info is found.
> - */
> -static int associativity_to_nid(const __be32 *associativity)
> +static int __associativity_to_nid(const __be32 *associativity,
> +				  int max_array_sz)
>  {
> -	int nid = NUMA_NO_NODE;
> +	int nid;
> +	/*
> +	 * primary_domain_index is 1 based array index.
> +	 */
> +	int index = primary_domain_index  - 1;
>  
> -	if (!numa_enabled)
> -		goto out;
> +	if (!numa_enabled || index >= max_array_sz)
> +		return NUMA_NO_NODE;
>  
> -	if (of_read_number(associativity, 1) >= primary_domain_index)
> -		nid = of_read_number(&associativity[primary_domain_index], 1);
> +	nid = of_read_number(&associativity[index], 1);
>  
>  	/* POWER4 LPAR uses 0xffff as invalid node */
>  	if (nid == 0xffff || nid >= nr_node_ids)
>  		nid = NUMA_NO_NODE;
> -out:
>  	return nid;
>  }
> +/*
> + * Returns nid in the range [0..nr_node_ids], or -1 if no useful NUMA
> + * info is found.
> + */
> +static int associativity_to_nid(const __be32 *associativity)
> +{
> +	int array_sz = of_read_number(associativity, 1);
> +
> +	/* Skip the first element in the associativity array */
> +	return __associativity_to_nid((associativity + 1), array_sz);
> +}
>  
>  static int __cpu_form2_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
>  {
> @@ -295,33 +305,39 @@ int of_node_to_nid(struct device_node *device)
>  }
>  EXPORT_SYMBOL(of_node_to_nid);
>  
> -static void __initialize_form1_numa_distance(const __be32 *associativity)
> +static void __initialize_form1_numa_distance(const __be32 *associativity,
> +					     int max_array_sz)
>  {
>  	int i, nid;
>  
>  	if (affinity_form != FORM1_AFFINITY)
>  		return;
>  
> -	nid = associativity_to_nid(associativity);
> +	nid = __associativity_to_nid(associativity, max_array_sz);
>  	if (nid != NUMA_NO_NODE) {
>  		for (i = 0; i < distance_ref_points_depth; i++) {
>  			const __be32 *entry;
> +			int index = be32_to_cpu(distance_ref_points[i]) - 1;
> +
> +			/*
> +			 * broken hierarchy, return with broken distance table
> +			 */
> +			if (WARN(index >= max_array_sz, "Broken ibm,associativity property"))
> +				return;
>  
> -			entry = &associativity[be32_to_cpu(distance_ref_points[i])];
> +			entry = &associativity[index];
>  			distance_lookup_table[nid][i] = of_read_number(entry, 1);
>  		}
>  	}
>  }
>  
> -static void initialize_form1_numa_distance(struct device_node *node)
> +static void initialize_form1_numa_distance(const __be32 *associativity)
>  {
> -	const __be32 *associativity;
> -
> -	associativity = of_get_associativity(node);
> -	if (!associativity)
> -		return;
> +	int array_sz;
>  
> -	__initialize_form1_numa_distance(associativity);
> +	array_sz = of_read_number(associativity, 1);
> +	/* Skip the first element in the associativity array */
> +	__initialize_form1_numa_distance(associativity + 1, array_sz);
>  }
>  
>  /*
> @@ -334,7 +350,13 @@ void update_numa_distance(struct device_node *node)
>  	if (affinity_form == FORM0_AFFINITY)
>  		return;
>  	else if (affinity_form == FORM1_AFFINITY) {
> -		initialize_form1_numa_distance(node);
> +		const __be32 *associativity;
> +
> +		associativity = of_get_associativity(node);
> +		if (!associativity)
> +			return;
> +
> +		initialize_form1_numa_distance(associativity);
>  		return;
>  	}
>  
> @@ -586,27 +608,17 @@ static int get_nid_and_numa_distance(struct drmem_lmb *lmb)
>  
>  	if (primary_domain_index <= aa.array_sz &&
>  	    !(lmb->flags & DRCONF_MEM_AI_INVALID) && lmb->aa_index < aa.n_arrays) {
> -		index = lmb->aa_index * aa.array_sz + primary_domain_index - 1;
> -		nid = of_read_number(&aa.arrays[index], 1);
> +		const __be32 *associativity;
>  
> -		if (nid == 0xffff || nid >= nr_node_ids)
> -			nid = default_nid;
> +		index = lmb->aa_index * aa.array_sz;
> +		associativity = &aa.arrays[index];
> +		nid = __associativity_to_nid(associativity, aa.array_sz);
>  		if (nid > 0 && affinity_form == FORM1_AFFINITY) {
> -			int i;
> -			const __be32 *associativity;
> -
> -			index = lmb->aa_index * aa.array_sz;
> -			associativity = &aa.arrays[index];
>  			/*
> -			 * lookup array associativity entries have different format
> -			 * There is no length of the array as the first element.
> +			 * lookup array associativity entries have
> +			 * no length of the array as the first element.
>  			 */
> -			for (i = 0; i < distance_ref_points_depth; i++) {
> -				const __be32 *entry;
> -
> -				entry = &associativity[be32_to_cpu(distance_ref_points[i]) - 1];
> -				distance_lookup_table[nid][i] = of_read_number(entry, 1);
> -			}
> +			__initialize_form1_numa_distance(associativity, aa.array_sz);
>  		}
>  	}
>  	return nid;
> @@ -632,11 +644,11 @@ int of_drconf_to_nid_single(struct drmem_lmb *lmb)
>  
>  	if (primary_domain_index <= aa.array_sz &&
>  	    !(lmb->flags & DRCONF_MEM_AI_INVALID) && lmb->aa_index < aa.n_arrays) {
> -		index = lmb->aa_index * aa.array_sz + primary_domain_index - 1;
> -		nid = of_read_number(&aa.arrays[index], 1);
> +		const __be32 *associativity;
>  
> -		if (nid == 0xffff || nid >= nr_node_ids)
> -			nid = default_nid;
> +		index = lmb->aa_index * aa.array_sz;
> +		associativity = &aa.arrays[index];
> +		nid = __associativity_to_nid(associativity, aa.array_sz);
>  	}
>  	return nid;
>  }
> @@ -939,7 +951,7 @@ static int __init parse_numa_properties(void)
>  
>  		if (__vphn_get_associativity(i, vphn_assoc) == 0) {
>  			nid = associativity_to_nid(vphn_assoc);
> -			__initialize_form1_numa_distance(vphn_assoc);
> +			initialize_form1_numa_distance(vphn_assoc);
>  		} else {
>  
>  			/*
> @@ -953,7 +965,7 @@ static int __init parse_numa_properties(void)
>  			associativity = of_get_associativity(cpu);
>  			if (associativity) {
>  				nid = associativity_to_nid(associativity);
> -				__initialize_form1_numa_distance(associativity);
> +				initialize_form1_numa_distance(associativity);
>  			}
>  			of_node_put(cpu);
>  		}
> @@ -993,7 +1005,7 @@ static int __init parse_numa_properties(void)
>  		associativity = of_get_associativity(memory);
>  		if (associativity) {
>  			nid = associativity_to_nid(associativity);
> -			__initialize_form1_numa_distance(associativity);
> +			initialize_form1_numa_distance(associativity);
>  		} else
>  			nid = default_nid;
>  

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson