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On 6/1/20 2:50 PM, Daniel Henrique Barboza wrote:
> Hi,
>
> This series implements a convenience feature for the case where
> the user defines an incomplete NUMA topology in the domain,
> when the sum of all cpus in each NUMA cell is less than the
> maximum vcpus count of the domain.
>
> This is an implementation based on Peter Krempa's suggestion in [1].
> The documentation patch (04), aside from documentating this new
> behavior, while also letting the user know that using incomplete
> NUMA topologies are not advised.
>
> This feature does not break migration ABI. I tested it in a migration
> using an incomplete NUMA topology domain to migrate to another host
> with a patched Libvirt. A guest with this NUMA topology, declaring
> 9 vcpus and short of 7 vcpus to complete the total of 16:
>
> <vcpu placement='auto'>16</vcpu>
> [...]
> <cpu mode='custom' match='exact' check='none'>
> <model fallback='forbid'>POWER9</model>
> <numa>
> <cell id='0' cpus='0-1,6' memory='3906250' unit='KiB'/>
> <cell id='1' cpus='2-4' memory='3906250' unit='KiB'/>
> <cell id='2' cpus='10,12' memory='3906250' unit='KiB'/>
> <cell id='3' cpus='14' memory='3906250' unit='KiB'/>
> </numa>
> </cpu>
>
> Successfully migrates to a patched Libvirt, ending up with
> this topology where the missing VCPUs were added to node 0:
>
> <vcpu placement='auto'>16</vcpu>
> [...]
> <cpu mode='custom' match='exact' check='none'>
> <model fallback='forbid'>POWER9</model>
> <numa>
> <cell id='0' cpus='0-1,5-9,11,13,15' memory='3932160' unit='KiB'/>
> <cell id='1' cpus='2-4' memory='3932160' unit='KiB'/>
> <cell id='2' cpus='10,12' memory='3932160' unit='KiB'/>
> <cell id='3' cpus='14' memory='3932160' unit='KiB'/>
> </numa>
> </cpu>
>
>
> [1] https://www.redhat.com/archives/libvir-list/2019-June/msg00263.html
>
> Daniel Henrique Barboza (5):
> numa_conf.c: add helper functions for cpumap operations
> qemu_domain.c: NUMA CPUs auto-fill for incomplete topologies
> qemuxml2xmltest.c: add NUMA vcpus auto fill tests
> formatdomain.html.in: document the NUMA cpus auto fill feature
> qemu_validate.c: revert NUMA CPU range user warning
>
> docs/formatdomain.html.in | 11 ++++-
> src/conf/numa_conf.c | 46 ++++++++++++++++++
> src/conf/numa_conf.h | 3 ++
> src/libvirt_private.syms | 1 +
> src/qemu/qemu_domain.c | 47 +++++++++++++++++++
> src/qemu/qemu_domain.h | 4 ++
> src/qemu/qemu_driver.c | 9 ++++
> src/qemu/qemu_validate.c | 19 ++------
> .../numavcpus-topology-mismatch.xml | 37 +++++++++++++++
> ...avcpus-topology-mismatch.x86_64-latest.xml | 38 +++++++++++++++
> tests/qemuxml2xmltest.c | 1 +
> 11 files changed, 201 insertions(+), 15 deletions(-)
> create mode 100644 tests/qemuxml2argvdata/numavcpus-topology-mismatch.xml
> create mode 100644 tests/qemuxml2xmloutdata/numavcpus-topology-mismatch.x86_64-latest.xml
>