Re: [libvirt] [PATCH] Support CPU less NUMA node.

-----Original Message----- From: Peter Krempa [mailto:pkrempa@redhat.com] Sent: Tuesday, April 25, 2017 4:33 PM To: Feng, Shaohe <shaohe.feng(a)intel.com&gt; Cc: libvir-list(a)redhat.com; Du, Dolpher <dolpher.du(a)intel.com>; Zyskowski, Robert <robert.zyskowski(a)intel.com>; Uminski, Piotr <Piotr.Uminski(a)intel.com>; Daniluk, Lukasz <lukasz.daniluk(a)intel.com>; Zang, Rui <rui.zang(a)intel.com>; Chen, He <he.chen(a)intel.com>; jdenemar(a)redhat.com Subject: Re: [libvirt] [PATCH] Support CPU less NUMA node. On Thu, Apr 20, 2017 at 19:22:49 +0800, Feng, Shaohe wrote: > Thanks Peter for the comments. > Will update it in the next version. > > On 2017年04月20日 19:17, Peter Krempa wrote: > > On Thu, Apr 20, 2017 at 03:49:29 +0000, Shaohe Feng wrote: > > > Some platform NUMA node does not include cpu, such as Phi. > > > > > > This patch support CPU less NUMA node. > > > But there must be one CPU cell node for a guest. > > > Also must assign the host nodeset for this guest cell node. > > Additionally to the review below: > > > > Did qemu always support this? If not, you need to add code which > > will allow such configuration only if qemu supports this (adding a > > capability bit etc ...). > need to check it. > > Also please elaborat how is this better than adding a regular numa > > node whith cpus which are disabled. In such case you can still add > > more cpus via the hotplug API in case you desire so. > do you means add an extra attribute "disable" for cpus? > such as > > <cell id='1' cpus="" cpu_disable="true" "memory='512000' unit='KiB'/> Why would you do that? You can specify cpus="some-sane-cpu-set" and then using the <vcpus> element disable the given set. See http://libvirt.org/formatdomain.html#elementsCPUAllocation