Re: [libvirt] [PATCH v1 1/1] virhostcpu.c: consider empty NUMA nodes in topology validation

Some devices creates empty (= cpu-less) NUMA nodes to host its memory. This results in topologies where the following sanity rule does not apply as is: nodes * sockets * cores * threads = total_cpus As a result, a call to 'virsh nodeinfo' will return the default value (1) to nodes, sockets and threads, while cores defaults to the total_cpus value. For example, in a Power9 host that has 160 total cpus, 4 cpu-less NUMA nodes, 2 populated NUMA nodes, 1 socket per populated node, 20 cores per socket and 4 threads per socket: $ virsh nodeinfo CPU model: ppc64le CPU(s): 160 CPU frequency: 3783 MHz CPU socket(s): 1 Core(s) per socket: 160 Thread(s) per core: 1 NUMA cell(s): 1 Memory size: 535981376 KiB This patch adjusts virHostCPUGetInfoPopulateLinux to count the cpu-less NUMA nodes and discard them in the sanity rule, changing it to: (nodes - empty_nodes) * sockets * cores * threads = total_cpus And with this new rule, virsh nodeinfo will return the appropriate info for those topologies, without changing the behavior for any other scenario it was previously working. This is the resulting output of nodeinfo after this patch in the same Power9 host mentioned above: $ virsh nodeinfo CPU model: ppc64le CPU(s): 160 CPU frequency: 3783 MHz CPU socket(s): 1 Core(s) per socket: 20 Thread(s) per core: 4 NUMA cell(s): 6 Memory size: 535981376 KiB