Reza Arbab <ar...@linux.vnet.ibm.com> writes: > On Thu, May 25, 2017 at 04:19:53PM +1000, Michael Ellerman wrote: >>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? > > I don't know what the reasoning behind that statement was at the time, > but as far as I can tell, the only thing missing for node hotplug now is > Balbir's patchset [1]. He fixes the resource issue which motivated > 3af229f2071f and reverts it. > > With that set, I can instantiate a new numa node just by doing > add_memory(nid, ...) where nid doesn't currently exist.
But does that actually happen on any real system? cheers
