Re: [PATCH v12 7/8] x86/resctrl: Sub NUMA Cluster detection and enable

[Reinette Chatre]

Hi Tony,

On 11/30/2023 4:37 PM, Tony Luck wrote:
> On Thu, Nov 30, 2023 at 03:40:52PM -0800, Reinette Chatre wrote:
>> Hi Tony,
>>
>> On 11/30/2023 2:43 PM, Tony Luck wrote:
>>> On Thu, Nov 30, 2023 at 01:47:10PM -0800, Reinette Chatre wrote:

>> for something that does not change while not holding the hotplug lock. Reading its
>> description more closely also makes me wonder if the later
>> 	num_online_cpus() != num_present_cpus()
>> should also maybe be 
>> 	num_online_cpus() != num_possible_cpus() ?
>> It seems to more closely match the intention.
> 
> This seems problematic. On a system that does support physical CPU
> hotplug num_possible_cpus() may be some very large number. Reserving
> space for CPUs that can be added later. None of those CPUs can be online
> (obviously!). So this test would fail on such a system.

Thank you for clarifying. It was not obvious to me how these bitmaps are
different with physical hotplug. 

Reinette