Michael Bringmann [off-list ref] writes:

On 05/24/2017 06:19 AM, Michael Ellerman wrote:

quoted

Michael Bringmann [off-list ref] writes:

quoted

With or without 3af229f2071f, we would still need to add something, somewhere to add new
bits to the 'node_possible_map'.  That is not being done.

You mustn't add bits to the possible map after boot.

That's its purpose, to tell you what nodes could ever *possibly* exist.

The problem that I have been encountering is that the 'possible map' did *not*
show all of the possible nodes.

OK so how did that happen?

The commit message for 3af229f2071f says:

    In practice, we never see a system with 256 NUMA nodes, and in fact, we
    do not support node hotplug on power in the first place, so the nodes
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    that are online when we come up are the nodes that will be present for
    the lifetime of this kernel.

Is that no longer true?

cheers