[PATCH 1/3] powerpc/mm/hash: Avoid resizing-down HPT on first memory hotplug

[Leonardo Bras]

Hello David, thanks for your feedback.

On Mon, 2021-03-22 at 17:49 +1100, David Gibson wrote:
> I don't love this approach.  Adding the extra flag at this level seems
> a bit inelegant, and it means we're passing up an easy opportunity to
> reduce our resource footprint on the host.

I understand, but trying to reduce resource footprint in host, and
mostly failing is what causes hot-add and hot-remove to take so long.

> But... maybe we'll have to do it.  I'd like to see if we can get
> things to work well enough with just the "batching" to avoid multiple
> resize attempts first.

This batching is something I had thought a lot about.
Problem is that there are a lot of generic interfaces between memory
hotplug and actually resizing HPT. I tried a simpler approach in
patches 2 & 3, so I don't touch much stuff there.

Best regards,
Leonardo Bras