Re: [PATCH 1/2] mm/memory_hotplug: allow marking of memory sections as hotpluggable

Mike Rapoport
2020-10-21T09:59:28Z

On Sat, Oct 17, 2020 at 11:36:39AM +0200, David Hildenbrand wrote:
> On 17.10.20 10:26, Mike Rapoport wrote:
> > On Fri, Oct 16, 2020 at 07:02:23PM -0700, Sudarshan Rajagopalan wrote:
> >> Certain architectures such as arm64 doesn't allow boot memory to be
> >> offlined and removed. Distinguish certain memory sections as
> >> "hotpluggable" which can be marked by module drivers stating to memory
> >> hotplug layer that these sections can be offlined and then removed.
> >
> > I don't quite follow why marking sections as hotpluggable or not should
> > be done by a device driver. Can you describe in more details your
> > use-case and why there is a need to add a flag to the memory map?
> >
>
> This seems to be related to
>
> https://lkml.kernel.org/r/de8388df2fbc5a6a33aab95831ba7db4@codeaurora.org

Thanks for the pointer.

> After reading how the driver is trying to abuse memory hot(un)plug
> infrastructure, my tentative
>
> Nacked-by: David Hildenbrand <david@redhat.com>

I also don't think we would want to let drivers play with the memory
map.

> --
> Thanks,
>
> David / dhildenb
>

--
Sincerely yours,
Mike.