On Wed 24-06-20 09:48:37, Ben Widawsky wrote: > On 20-06-24 10:25:59, Michal Hocko wrote: > > On Fri 19-06-20 09:24:09, Ben Widawsky wrote: > > > Calling out some distinctions first as I understand it, and the > > > reasoning of the patch: > > > numa_node_id() - The node id for the currently running CPU. > > > numa_mem_id() - The node id for the closest memory node. > > > > Correct > > > > > The case where they are not the same is CONFIG_HAVE_MEMORYLESS_NODES. > > > Only ia64 and powerpc support this option, so it is perhaps not a very > > > interesting situation to most. > > > > Other arches can have nodes without any memory as well. Just offline all > > the managed memory via hotplug... (please note that such node still > > might have memory present! Just not useable by the page allocator) > > You must have CONFIG_HAVE_MEMORYLESS_NODES defined. So I believe that this > change is limited to ia64 and powerpc. I don't think there is a way to set it > outside of those arches. I have tried to say that while other arches (like x86) do not have CONFIG_HAVE_MEMORYLESS_NODES defined they still can end up with a memory node without any memory. Just use memory hotplug... -- Michal Hocko SUSE Labs
