Re: [PATCH V6 13/14] qapi: examine IOThread attachment status via query-iothreads

[Markus Armbruster <armbru@redhat.com>]

Zhang Chen <zhangckid@gmail.com> writes:

> Extend the 'IOThreadInfo' structure to include attachment metrics.
> This allows users to monitor the associated devices by identify them
> by their QOM paths.
>
> New fields added to IOThreadInfo:
> - @holders: IoThreadHolder(QOM path or block node name) of the devices
>             currently associated with this iothread.

See "I'm confused" below.

>
> These fields are also exposed via the Human Monitor Interface (HMP)
> command 'info iothreads' to assist with manual debugging and
> performance tuning.
>
> Signed-off-by: Zhang Chen <zhangckid@gmail.com>

[...]

> diff --git a/qapi/misc.json b/qapi/misc.json
> index d65d8012b2..e173d54a5e 100644
> --- a/qapi/misc.json
> +++ b/qapi/misc.json
> @@ -94,7 +94,8 @@
>  # @IoThreadHolderKind:
>  #
>  # @block-node: Block node name.
> -# @qom-object: Standard QOM path.
> +#
> +# @qom-object: QOM path.
>  #
>  # Since: 11.0
>  ##

Squash this into PATCH 02, please.

> @@ -104,7 +105,7 @@
>  ##
>  # @IoThreadHolder:
>  #
> -# @type: Current IoThread holder type support QOM path and Block node.
> +# @type: Current IoThread holder type support QOM path and block node.

This, too.

>  #
>  # Since: 11.0
>  ##
> @@ -124,6 +125,13 @@
>  #
>  # @thread-id: ID of the underlying host thread
>  #
> +# @holders: IoThreadHolder(QOM path or block node name) of the devices

Space before (

> +#     currently associated with this iothread.  Users can pre-allocate

I'm confused.  What is holding what?

A QOM object / block node / monitor holding an I/O thread?

> +#     multiple iothread objects to serve as a persistent thread pool.
> +#     When a device is hot-unplugged, it is detached from its
> +#     iothread, but the iothread remains available, allowing future
> +#     hot-plugged devices to attach to it.
> +#
>  # @poll-max-ns: maximum polling time in ns, 0 means polling is
>  #     disabled (since 2.9)
>  #
> @@ -141,6 +149,7 @@
>  { 'struct': 'IOThreadInfo',
>    'data': {'id': 'str',
>             'thread-id': 'int',
> +           'holders': ['IoThreadHolder'],
>             'poll-max-ns': 'int',
>             'poll-grow': 'int',
>             'poll-shrink': 'int',
> @@ -166,6 +175,8 @@
>  #              {
>  #                 "id":"iothread0",
>  #                 "thread-id":3134,
> +#                 "holders":["/machine/peripheral/blk1/virtio-backend",
> +#                            "/machine/peripheral/blk0/virtio-backend"],
>  #                 "poll-max-ns":32768,
>  #                 "poll-grow":0,
>  #                 "poll-shrink":0,
> @@ -174,6 +185,7 @@
>  #              {
>  #                 "id":"iothread1",
>  #                 "thread-id":3135,
> +#                 "holders":["/machine/peripheral/blk2/virtio-backend"],
>  #                 "poll-max-ns":32768,
>  #                 "poll-grow":0,
>  #                 "poll-shrink":0,