On Wed, Jul 08, 2020 at 06:10:19PM +0200, David Hildenbrand wrote:

On 08.07.20 17:50, Dan Williams wrote:

quoted

On Wed, Jul 8, 2020 at 3:04 AM David Hildenbrand [off-list ref] wrote:

quoted

I'm not quite understanding the concern, or requirement about
"updating memblock" in the hotplug path. The routines
memory_add_physaddr_to_nid() and phys_to_target_node() are helpers to
interrogate platform-firmware numa info through a common abstraction.
They place no burden on the memory hotplug code they're just used to
see if a hot-added range lies within an existing node span when
platform-firmware otherwise fails to communicate a node. x86 can
continue to back those helpers with numa_meminfo, arm64 can use a
generic memblock implementation and other archs can follow the arm64
example if they want better numa answers for drivers.

See memblock_add_node()/memblock_remove() in mm/memory_hotplug.c. I
don't want that code be reactivated for x86/s390x. That's all I am saying.

And these have actual meaning only on arm64 because powerpc does not
rely on memblock for memory hot(un)plug, AFAIU.

Anyway, at the moment we can use memblock on hotplug path only on arm64
and I don't think its the path worth exploring.

-- 
Thanks,

David / dhildenb

-- 
Sincerely yours,
Mike.

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