Re: [RFC PATCH 1/3] mm/numa: add exclusive node pool and numa=standby boot parameter

[Gregory Price]

On Sun, Jun 14, 2026 at 12:08:31PM +0300, Mike Rapoport wrote:
> On Thu, Jun 11, 2026 at 10:04:01AM -0400, Gregory Price wrote:
> > On Thu, Jun 11, 2026 at 12:00:17PM +0300, Mike Rapoport wrote:
>  
> > So really i think you're pointing out that futex_init() here probably
> > shouldn't be using num_possible_nodes?
> 
> I'd rather say that num_possible_nodes() with and without CXL (or other
> differentiated memory) has different semantics.
> Maybe we need to add a new primitive for possible differentiated nodes and
> keep num_possible_nodes() to mean "number of possible nodes with normal
> memory".
>  

We'd have to define "normal" here a little more discretely.

Normal = N_MEMORY at __init?
Normal = N_MEMORY in the future?

We also use the possible_nodes() mask to allocate per-node pgdat, so
the futex example is largely just another "hey look at this thing,
I wonder what other stuff is out there".

~Gregory