Re: [PATCH 1/6] arm64/mm: Enable sysfs based memory hot add interface

[Anshuman Khandual]

On 04/03/2019 06:42 PM, Robin Murphy wrote:
> On 03/04/2019 09:20, David Hildenbrand wrote:
>> On 03.04.19 06:30, Anshuman Khandual wrote:
>>> Sysfs memory probe interface (/sys/devices/system/memory/probe) can accept
>>> starting physical address of an entire memory block to be hot added into
>>> the kernel. This is in addition to the existing ACPI based interface. This
>>> just enables it with the required config CONFIG_ARCH_MEMORY_PROBE.
>>>
>>
>> We recently discussed that the similar interface for removal should
>> rather be moved to a debug/test module
>>
>> I wonder if we should try to do the same for the sysfs probing
>> interface. Rather try to get rid of it than open the doors for more users.
> 
> Agreed - if this option even exists in a released kernel, there's a risk that 
> distros will turn it on for the sake of it, and at that point arm64 is stuck 
> carrying the same ABI baggage as well.

True. Only if we really dont like that interface.

> 
> If users turn up in future with a desperate and unavoidable need for the 
> legacy half-an-API on arm64, we can always reconsider adding it at that 
> point. It was very much deliberate that my original hot-add support did not 
> include a patch like this one.

Sure. Will drop this one next time around.