Re: [PATCH v6 6/6] powerpc/pseries: Consolidate form1 distance initialization into a helper

["Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>]

On 8/6/21 12:17 PM, David Gibson wrote:
> On Tue, Jul 27, 2021 at 03:33:11PM +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.
> 
> Oh... sorry.. comments on the earlier patch were from before I read
> and saw you adjusted things here.
> 
>>
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
>> ---
>>   arch/powerpc/mm/numa.c | 83 ++++++++++++++++++++++++++----------------
>>   1 file changed, 51 insertions(+), 32 deletions(-)
>>
>> diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
>> index fffb3c40f595..7506251e17f2 100644
>> --- a/arch/powerpc/mm/numa.c
>> +++ b/arch/powerpc/mm/numa.c
>> @@ -171,19 +171,19 @@ 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;
>> +	/*
>> +	 * primary_domain_index is 1 based array index.
>> +	 */
>> +	int index = primary_domain_index  - 1;
>>   
>> -	if (!numa_enabled)
>> +	if (!numa_enabled || index >= max_array_sz)
>>   		goto out;
> 
> You don't need a goto, you can just return NUMA_NO_NODE.

updated

> 
>>   
>> -	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)
>> @@ -191,6 +191,17 @@ static int associativity_to_nid(const __be32 *associativity)
>>   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)
>>   {
>> @@ -295,24 +306,41 @@ 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
> 
> WARN_ON, maybe?


updated

> 
>> +			 */
>> +			if (index >= max_array_sz)
>> +				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(const __be32 *associativity)
> 
> Do you actually use this in-between wrapper?

yes used in

static void initialize_form1_numa_distance(struct device_node *node)
{
	const __be32 *associativity;

	associativity = of_get_associativity(node);
	if (!associativity)
		return;

	__initialize_form1_numa_distance(associativity);
}



> 
>> +{
>> +	int array_sz;
>> +
>> +	array_sz = of_read_number(associativity, 1);
>> +	/* Skip the first element in the associativity array */
>> +	___initialize_form1_numa_distance(associativity + 1, array_sz);
>> +}
>> +
>>   static void initialize_form1_numa_distance(struct device_node *node)
>>   {
>>   	const __be32 *associativity;
>> @@ -586,27 +614,18 @@ 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);
> 
> Better, thanks.
> 
>>   		}
>>   	}
>>   	return nid;
>> @@ -632,11 +651,11 @@ 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;
>>   }
> 


-aneesh