Re: [PATCH v2 1/1] mm: numa_memblks: Identify the accurate NUMA ID of CFMW

[Jonathan Cameron]

On Fri, 6 Feb 2026 11:32:09 -0500
Gregory Price <gourry@xxxxxxxxxx> wrote:

> On Fri, Feb 06, 2026 at 04:26:44PM +0000, Jonathan Cameron wrote:
> > > 
> > > This should fall out cleanly.
> > > 
> > > The additional nodes won't be associated with anything, but could be
> > > used for hotplug - I imagine.
> > >   
> > 
> > That aligns with what I was thinking as a first solution to allowing this
> > to be more dynamic.   We can get clever later if this doesn't prove sufficient.
> >   
> 
> I can get this out pretty quickly, hopefully sometime next week.
> 
> I had a long talk with Dan about this topic previously, and I'm not sure
> how we get more dynamic than this to be honest.  nr_possible_nodes is
> *definitely* expected to be immutable after __init all over the kernel,
> it's used to allocate a memory.

Indeed. But that doesn't mean to say they are all in use after __init.

You end up allocating a bunch of space, that is not used until there
is some memory there.  Not a problem.

So dynamic nr_possible_nodes is tricky.  Dynamic allocation of stuff into
those nodes is fine. That happens with memory hotplug today.

J
> 
> Surface area is very large here.
> 
> ~Gregory