Re: [PATCH v3 1/3] powerpc/numa: Set numa_node for all possible cpus

Michael Ellerman
2020-05-11T11:26:53Z

Srikar Dronamraju <srikar@linux.vnet.ibm.com> writes:
> * Christopher Lameter <cl@linux.com> [2020-05-02 22:55:16]:
>
>> On Fri, 1 May 2020, Srikar Dronamraju wrote:
>>
>> > - for_each_present_cpu(cpu)
>> > - numa_setup_cpu(cpu);
>> > + for_each_possible_cpu(cpu) {
>> > + /*
>> > + * Powerpc with CONFIG_NUMA always used to have a node 0,
>> > + * even if it was memoryless or cpuless. For all cpus that
>> > + * are possible but not present, cpu_to_node() would point
>> > + * to node 0. To remove a cpuless, memoryless dummy node,
>> > + * powerpc need to make sure all possible but not present
>> > + * cpu_to_node are set to a proper node.
>> > + */
>> > + if (cpu_present(cpu))
>> > + numa_setup_cpu(cpu);
>> > + else
>> > + set_cpu_numa_node(cpu, first_online_node);
>> > + }
>> > }
>>
>> Can this be folded into numa_setup_cpu?
>>
>> This looks more like numa_setup_cpu needs to change?
>
> We can fold this into numa_setup_cpu().
>
> However till now we were sure that numa_setup_cpu() would be called only for
> a present cpu. That assumption will change.
> + (non-consequential) an additional check everytime cpu is hotplugged in.
>
> If Michael Ellerman is okay with the change, I can fold it in.

Yes I agree it would be better in numa_setup_cpu().

cheers