On Mon, Jun 16, 2014 at 05:25:00PM -0700, Nishanth Aravamudan wrote: [...] > > But you seem to claim you need 3 nodes with non-contiguous IDs. In that > > case, which exactly is the guest-visible difference you expect to get > > between: > > -numa node,nodeid=0,cpus=0-7,memory=0 \ > > -numa node,nodeid=1 \ > > -numa node,nodeid=2,cpus=0-3,mem=1040 \ > > -numa node,nodeid=3 \ > > -numa node,nodeid=4,cpus=4-7,mem=1040 > > I guess here you'd see 5 NUMA nodes in Linux, with 0, 1 and 3 having no > memory. > > > and > > -numa node,nodeid=0,cpus=0-7,memory=0 \ > > -numa node,nodeid=2,cpus=0-3,mem=1040 \ > > -numa node,nodeid=4,cpus=4-7,mem=1040 > > ? > > And here you'd see 3 NUMA nodes in Linux, with 0 having no memory. I > would think the principle of least surprise means qemu doesn't change > the topology from the user-requested one without any indicate that's > happening?
OK, so we are on the same page. The problem is: with your patch, both cases above are exactly the same. That's what confused me: I thought you wanted to implement the former, but you want the latter. When changing the code to allow non-contiguous node IDs, I believe we need to differentiate those cases and implement both correctly. Otherwise we will be forced to break compatibility in the future. -- Eduardo
