Re: [PATCH v5 25/36] mm/memory_hotplug: support N_MEMORY_PRIVATE node hotplug

On Thu, Aug 06, 2026 at 11:30:08AM +0800, Qiqi Li wrote:
> Hi Gregory,
> 
> On 7/21/2026 3:34 AM, Gregory Price wrote:
> 
> > Add add_private_memory_driver_managed() to let modules hotplug
> > memory onto an N_MEMORY_PRIVATE node they control.
> 
> I am trying to understand how the nid passed to
> add_private_memory_driver_managed() is expected to be provisioned.
> 
> From what I can see, both node_private_register() and
> __add_memory_resource() require the nid to already be present in
> node_possible_map. My understanding is therefore that this patch
> supports hotplugging private memory onto an existing possible node,
> rather than creating a new possible node ID at runtime.
> 
> For example, in the use case I am looking at, the device's private
> node is not described by firmware. Would its nid need to be reserved
> during early NUMA initialization, or is there another mechanism that
> I may have missed?
> 

It would need to be reserved, and you could use numa emulation but
that's clunky.  I have an RFC for exactly this issue - though i haven't
pushed it further yet.

https://lore.kernel.org/all/[email protected]/

> Also, could you please Cc me on future revisions of this series?
> I would appreciate it and would be happy to follow the work:)
> 
> Thanks,
> Qiqi