Re: [PATCH RFCv2 3/4] mm/memory_hotplug: Introduce and use more memory types

[Michal SuchÃnek]

On Fri, 30 Nov 2018 18:59:21 +0100
David Hildenbrand <david@xxxxxxxxxx> wrote:

> Let's introduce new types for different kinds of memory blocks and use
> them in existing code. As I don't see an easy way to split this up,
> do it in one hunk for now.
> 
> acpi:
>  Use DIMM or DIMM_UNREMOVABLE depending on hotremove support in the kernel.
>  Properly change the type when trying to add memory that was already
>  detected and used during boot (so this memory will correctly end up as
>  "acpi" in user space).
> 
> pseries:
>  Use DIMM or DIMM_UNREMOVABLE depending on hotremove support in the kernel.
>  As far as I see, handling like in the acpi case for existing blocks is
>  not required.
> 
> probed memory from user space:
>  Use DIMM_UNREMOVABLE as there is no interface to get rid of this code
>  again.
> 
> hv_balloon,xen/balloon:
>  Use BALLOON. As simple as that :)
> 
> s390x/sclp:
>  Use a dedicated type S390X_STANDBY as this type of memory and it's
>  semantics are very s390x specific.
> 
> powernv/memtrace:
>  Only allow to use BOOT memory for memtrace. I consider this code in
>  general dangerous, but we have to keep it working ... most probably just
>  a debug feature.

I don't think it should be arbitrarily restricted like that.

Thanks

Michal