On 18.02.2014 [15:49:22 -0600], Christoph Lameter wrote: > On Tue, 18 Feb 2014, Nishanth Aravamudan wrote: > > > We use the topology provided by the hypervisor, it does actually reflect > > where CPUs and memory are, and their corresponding performance/NUMA > > characteristics. > > And so there are actually nodes without memory that have processors? Virtually (topologically as indicated to Linux), yes. Physically, I don't think they are, but they might be exhausted, which is we get sort of odd-appearing NUMA configurations. > Can the hypervisor or the linux arch code be convinced to ignore nodes > without memory or assign a sane default node to processors? I think this happens quite often, so I don't know that we want to ignore the performance impact of the underlying NUMA configuration. I guess we could special-case memoryless/cpuless configurations somewhat, but I don't think there's any reason to do that if we can make memoryless-node support work in-kernel? > > > Ok then also move the memory of the local node somewhere? > > > > This happens below the OS, we don't control the hypervisor's decisions. > > I'm not sure if that's what you are suggesting. > > You could also do this from the powerpc arch code by sanitizing the > processor / node information that is then used by Linux. I see what you're saying now, thanks! -Nish -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>