Re: [PATCH v2 3/3] qom: Link multiple numa nodes to device using a new object

[David Hildenbrand <david@redhat.com>]

On 09.10.23 14:30, Jonathan Cameron wrote:
> On Sun, 8 Oct 2023 01:47:40 +0530
> <ankita@nvidia.com> wrote:
> 
>> From: Ankit Agrawal <ankita@nvidia.com>
>>
>> NVIDIA GPU's support MIG (Mult-Instance GPUs) feature [1], which allows
>> partitioning of the GPU device resources (including device memory) into
>> several (upto 8) isolated instances. Each of the partitioned memory needs
>> a dedicated NUMA node to operate. The partitions are not fixed and they
>> can be created/deleted at runtime.
>>
>> Unfortunately Linux OS does not provide a means to dynamically create/destroy
>> NUMA nodes and such feature implementation is not expected to be trivial. The
>> nodes that OS discovers at the boot time while parsing SRAT remains fixed. So
>> we utilize the GI Affinity structures that allows association between nodes
>> and devices. Multiple GI structures per BDF is possible, allowing creation of
>> multiple nodes by exposing unique PXM in each of these structures.
>>
>> Introducing a new nvidia-acpi-generic-initiator object, which inherits from
>> the generic acpi-generic-initiator object to allow a BDF to be associated with
>> more than 1 nodes.
>>
>> An admin can provide the range of nodes using numa-node-start and
>> numa-node-count and link it to a device by providing its id. The following
>> sample creates 8 nodes and link them to the device dev0:
>>
>>          -numa node,nodeid=2 \
>>          -numa node,nodeid=3 \
>>          -numa node,nodeid=4 \
>>          -numa node,nodeid=5 \
>>          -numa node,nodeid=6 \
>>          -numa node,nodeid=7 \
>>          -numa node,nodeid=8 \
>>          -numa node,nodeid=9 \
>>          -device vfio-pci-nohotplug,host=0009:01:00.0,bus=pcie.0,addr=04.0,rombar=0,id=dev0 \
>>          -object nvidia-acpi-generic-initiator,id=gi0,device=dev0,numa-node-start=2,numa-node-count=8 \
> 
> If you go this way, use an array of references to the numa nodes instead of a start and number.
> There is no obvious reason why they should be contiguous that I can see.

Right, a uint16List should do.


-- 
Cheers,

David / dhildenb