Re: [PATCH 1/5] mm: Add support for unaccepted memory

Andi Kleen
2021-08-10T18:31:27Z

> So, this is right in the fast path of the page allocator. It's a
> one-time thing per 2M page, so it's not permanent.
>
> *But* there's both a global spinlock and a firmware call hidden in
> clear_page_offline(). That's *GOT* to hurt if you were, for instance,
> running a benchmark while this code path is being tickled. Not just to
>
> That could be just downright catastrophic for scalability, albeit
> temporarily

This would be only a short blib at initialization until the system
reaches steady state. So yes it would be temporary, but very short at that.

-Andi