Re: [PATCH 6/8] s390/mm: implement MEM_PHYS_ONLINE MEM_PHYS_OFFLINE memory notifiers

David Hildenbrand
2023-11-16T19:23:43Z

>>>
>>> Maybe s390x should just provide a dedicate interface to add these memory
>>> blocks instead of adding them during boot and then relying on the old way of
>>> using online/offline set them online/offline.
>>
>> Existing behavior:
>> The current 'lsmem -a' command displays both online and standby memory.
>>
>> interface changes:
>> If a new interface is introduced and standby memory is no longer listed,
>> the following consequences might occur:
>>
>> 1. Running 'lsmem -a' would only show online memory, potentially leading
>> to user complaints.
>
> That's why the new, clean way of doing it will require a world switch.
> If the admin wants the benefits of altmap/memmap allocation, it can be
> enabled.

BTW, thinking about it, I guess one could teach lsmem (and maybe chmem)
to consult additional interfaces on s390x to show standby memory that's
not added to the system yet.

--
Cheers,

David / dhildenb