Re: [PATCH v3 2/3] util/main-loop: Introduce the main loop into QOM

[Markus Armbruster <armbru@redhat.com>]

Nicolas Saenz Julienne <nsaenzju@redhat.com> writes:

> 'event-loop-base' provides basic property handling for all 'AioContext'
> based event loops. So let's define a new 'MainLoopClass' that inherits
> from it. This will permit tweaking the main loop's properties through
> qapi as well as through the command line using the '-object' keyword[1].
> Only one instance of 'MainLoopClass' might be created at any time.
>
> 'EventLoopBaseClass' learns a new callback, 'can_be_deleted()' so as to
> mark 'MainLoop' as non-deletable.
>
> [1] For example:
>       -object main-loop,id=main-loop,aio-max-batch=<value>
>
> Signed-off-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

[...]

> diff --git a/qapi/qom.json b/qapi/qom.json
> index eeb5395ff3..10800166e8 100644
> --- a/qapi/qom.json
> +++ b/qapi/qom.json
> @@ -528,6 +528,19 @@
>              '*poll-shrink': 'int',
>              '*aio-max-batch': 'int' } }
>  
> +##
> +# @MainLoopProperties:
> +#
> +# Properties for the main-loop object.
> +#
> +# @aio-max-batch: maximum number of requests in a batch for the AIO engine,
> +#                 0 means that the engine will use its default (default:0)
> +#
> +# Since: 7.1
> +##
> +{ 'struct': 'MainLoopProperties',
> +  'data': { '*aio-max-batch': 'int' } }
> +

IothreadProperties has the same member, with the same documentation.

Do main loop and iothreads have a common ancestor, conceptually?

If yes, it might make sense for MainLoopProperties and
IothreadProperties to have a common base type, and put @aio-max-batch
there.  This is not a demand.

>  ##
>  # @MemoryBackendProperties:
>  #
> @@ -818,6 +831,7 @@
>      { 'name': 'input-linux',
>        'if': 'CONFIG_LINUX' },
>      'iothread',
> +    'main-loop',
>      { 'name': 'memory-backend-epc',
>        'if': 'CONFIG_LINUX' },
>      'memory-backend-file',
> @@ -883,6 +897,7 @@
>        'input-linux':                { 'type': 'InputLinuxProperties',
>                                        'if': 'CONFIG_LINUX' },
>        'iothread':                   'IothreadProperties',
> +      'main-loop':                  'MainLoopProperties',
>        'memory-backend-epc':         { 'type': 'MemoryBackendEpcProperties',
>                                        'if': 'CONFIG_LINUX' },
>        'memory-backend-file':        'MemoryBackendFileProperties',

QAPI schema
Acked-by: Markus Armbruster <armbru@redhat.com>