Re: Ways to deprecate /sys/devices/system/memory/memoryX/phys_device ?

quoted

Otherwise, hot(un)plugging smaller granularity behaves more like memory
ballooning (and I think I don't have to tell you that ballooning is used
excessively even though it wastes memory on metadata ;) ). Anyhow,
that's another discussion.

Yeah, I am aware of that. And honestly subsection offlining makes very
little sense to me. It was hard to argue against that for nvdimm
usecases where we simply had to workaround the reality where devices
couldn't have been aligned properly. I do not think we want to claim a
support for general hotplug though. 

Totally agree, I also don't want to see actual sub-section
onlining/offlining in the core (e.g., virtio-mem emulates that on top,
but it behaves a lot more like memory ballooning).

[...]

quoted

quoted

There is only one certainty. Providing a long term interface with ever
growing (ab)users is a hard target. And shinyN might be needed in the
end. Who knows. My main point is that the existing interface is hitting
a wall on usecases which _do_not_care_ about memory hotplug. And that is
something we should be looking at.

Agreed. I can see 3 scenarios

a) no memory hotplug support, no sysfs.
b) memory hotplug support, no sysfs
c) memory hotplug support, sysfs

Starting with a) and c) is the easiest way to go.

Yes, the first and the simplest way would be to provide
memory_hotplug=[disabled|v1]

where disabled would be no sysfs interface, v1 would be the existing
infrastructure. I would hope to land with v2 in a future which would
provide a new interface.

Agreed.

-- 
Thanks,

David / dhildenb