On 27.08.2021 01:10, Stefano Stabellini wrote:
> On Wed, 11 Aug 2021, Wei Chen wrote:
>> @@ -29,3 +31,54 @@ void numa_set_node(int cpu, nodeid_t nid)
>>
>> cpu_to_node[cpu] = nid;
>> }
>> +
>> +void __init numa_init(bool acpi_off)
>> +{
>> + uint32_t idx;
>> + paddr_t ram_start = ~0;
>> + paddr_t ram_size = 0;
>> + paddr_t ram_end = 0;
>> +
>> + printk(XENLOG_WARNING
>> + "NUMA has not been supported yet, NUMA off!\n");
>
> NIT: please align
>
>
>> + /* Arm NUMA has not been implemented until this patch */
>
> "Arm NUMA is not implemented yet"
>
>
>> + numa_off = true;
>> +
>> + /*
>> + * Set all cpu_to_node mapping to 0, this will make cpu_to_node
>> + * function return 0 as previous fake cpu_to_node API.
>> + */
>> + for ( idx = 0; idx < NR_CPUS; idx++ )
>> + cpu_to_node[idx] = 0;
>> +
>> + /*
>> + * Make node_to_cpumask, node_spanned_pages and node_start_pfn
>> + * return as previous fake APIs.
>> + */
>> + for ( idx = 0; idx < MAX_NUMNODES; idx++ ) {
>> + node_to_cpumask[idx] = cpu_online_map;
>> + node_spanned_pages(idx) = (max_page - mfn_x(first_valid_mfn));
>> + node_start_pfn(idx) = (mfn_x(first_valid_mfn));
>> + }
>
> I just want to note that this works because MAX_NUMNODES is 1. If
> MAX_NUMNODES was > 1 then it would be wrong to set node_to_cpumask,
> node_spanned_pages and node_start_pfn for all nodes to the same values.
>
> It might be worth writing something about it in the in-code comment.
Plus perhaps BUILD_BUG_ON(MAX_NUMNODES != 1), so the issue is actually
noticed at build time once the constant gets changed?
Jan
