Re: [PATCH v2 4/4] mm/memory_hotplug: Remove MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE notifiers

David Hildenbrand
2025-10-09T19:03:38Z

On 09.10.25 15:18, Sumanth Korikkar wrote:
> MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE memory notifiers were introduced
> to prepare the transition of memory to and from a physically accessible
> state. This enhancement was crucial for implementing the "memmap on memory"
> feature for s390.
>
> With introduction of dynamic (de)configuration of hotpluggable memory,
> memory can be brought to accessible state before add_memory(). Memory
> can be brought to inaccessible state before remove_memory(). Hence,
> there is no need of MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE memory
> notifiers anymore.
>
> This basically reverts commit
> c5f1e2d18909 ("mm/memory_hotplug: introduce MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE notifiers")
> Additionally, apply minor adjustments to the function parameters of
> move_pfn_range_to_zone() and mhp_supports_memmap_on_memory() to ensure
> compatibility with the latest branch.
>
> Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
> ---

Acked-by: David Hildenbrand <david@redhat.com>

--
Cheers

David / dhildenb