Re: [PATCH v1 4/7] util: Add write-only "node-affinity" property for ThreadContext

[Markus Armbruster <armbru@redhat.com>]

David Hildenbrand <david@redhat.com> writes:

> Let's make it easier to pin threads created via a ThreadContext to
> all current CPUs belonging to given NUMA nodes.
>
> As "node-affinity" is simply a shortcut for setting "cpu-affinity", that
> property cannot be read and if the CPUs for a node change due do CPU
> hotplug, the CPU affinity will not get updated.

Color me confused.

> Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>  qapi/qom.json         |  7 +++-
>  util/meson.build      |  2 +-
>  util/thread-context.c | 84 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 91 insertions(+), 2 deletions(-)
>
> diff --git a/qapi/qom.json b/qapi/qom.json
> index 4775a333ed..d36bf3355f 100644
> --- a/qapi/qom.json
> +++ b/qapi/qom.json
> @@ -838,10 +838,15 @@
>  # @cpu-affinity: the CPU affinity for all threads created in the thread
>  #                context (default: QEMU main thread affinity)
>  #
> +# @node-affinity: shortcut for looking up the current CPUs for the given nodes
> +#                 and setting @cpu-affinity (default: QEMU main thread
> +#                 affinity)
> +#

Still confused.  Explain for dummies?  With an example, perhaps?

>  # Since: 7.2
>  ##
>  { 'struct': 'ThreadContextProperties',
> -  'data': { '*cpu-affinity': ['uint16'] } }
> +  'data': { '*cpu-affinity': ['uint16'],
> +            '*node-affinity': ['uint16'] } }
>  
>  
>  ##

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