Am Wed, 17 Aug 2016 09:58:55 -0400 schrieb Tejun Heo <t...@kernel.org>:
> Hello, Heiko. > > On Wed, Aug 17, 2016 at 12:19:53AM +0200, Heiko Carstens wrote: > > I think the easiest solution would be to simply assign all cpus, > > for which we do not have any topology information, to an arbitrary > > node; e.g. round robin. > > > > After all the case that cpus are added later is rare and the s390 > > fake numa implementation does not know about the memory topology. > > All it is doing is > > Ah, okay, so there really is no requirement for a newly coming up cpu > to be on a specific node. Well, "no requirement" this is not 100% correct. Currently we use the CPU topology information to assign newly coming CPUs to the "best fitting" node. Example: 1) We have we two fake NUMA nodes N1 and N2 with the following CPU assignment: - N1: cpu 1 on chip 1 - N2: cpu 2 on chip 2 2) A new cpu 3 is configured that lives on chip 2 3) We assign cpu 3 to N2 We do this only if the nodes are balanced. If N2 had already one more cpu than N1 we would assign the new cpu to N1. Michael
