Re: [Qemu-devel] [PATCH v2 1/4] qom: provide root container for internal objs

[Andreas Färber]

Hi,

Am 25.09.2017 um 10:14 schrieb Peter Xu:
> On Mon, Sep 25, 2017 at 09:14:21AM +0200, Andreas Färber wrote:
>> Am 25.09.2017 um 08:37 schrieb Peter Xu:
>>> We have object_get_objects_root() to keep user created objects, however
>>> no place for objects that will be used internally.  Create such a
>>> container for internal objects.
>>>
>>> CC: Andreas Färber <address@hidden>
>>> CC: Markus Armbruster <address@hidden>
>>> CC: Paolo Bonzini <address@hidden>
>>> Suggested-by: Daniel P. Berrange <address@hidden>
>>> Signed-off-by: Peter Xu <address@hidden>
>>> ---
>>>  include/qom/object.h | 10 ++++++++++
>>>  qom/object.c         |  5 +++++
>>>  2 files changed, 15 insertions(+)
>>>
>>> diff --git a/include/qom/object.h b/include/qom/object.h
>>> index f3e5cff..f567052 100644
>>> --- a/include/qom/object.h
>>> +++ b/include/qom/object.h
>>> @@ -1214,6 +1214,16 @@ Object *object_get_root(void);
>>>  Object *object_get_objects_root(void);
>>>  
>>>  /**
>>> + * object_get_internal_root:
>>> + *
>>> + * Get the container object that holds internally used object
>>> + * instances. This is the object at path "/internal-objects"
>>> + *
>>> + * Returns: the internal object container
>>> + */
>>> +Object *object_get_internal_root(void);
>>> +
>>> +/**
>>>   * object_get_canonical_path_component:
>>>   *
>>>   * Returns: The final component in the object's canonical path.  The 
>>> canonical
>>> diff --git a/qom/object.c b/qom/object.c
>>> index 3e18537..857cee7 100644
>>> --- a/qom/object.c
>>> +++ b/qom/object.c
>>> @@ -1370,6 +1370,11 @@ Object *object_get_objects_root(void)
>>>      return container_get(object_get_root(), "/objects");
>>>  }
>>>  
>>> +Object *object_get_internal_root(void)
>>> +{
>>> +    return container_get(object_get_root(), "/internal-objects");
>>
>> Whatever you expose in the QOM tree is no longer internal. Other name?
> 
> Hi, Andreas,
> 
> If you mean "info qom-tree" here, can we still treat it as internal?
> Since after all it's not exposed in QMP (while IMHO QMP is the
> official protocol for QEMU clients).  And IIUC some HMP commands do
> dump some internal structs for debugging purpose (like: "info
> ramblock").
> 
> Or, do you have any suggestion?
> 
> (I did think about something like "hidden-objects", but I believe they
>  are not hidden as well if we think they are not internal...)

I'm on travels and only seeing this 1/4 without context - according to
Manos apparently something about IOThreads.

The reason that certain container groups such as "/machine/peripheral"
exist was more of a legacy reason for migration from qdev, so yes I am
critical of "/hidden-objects" as well. If the objects are not related to
an existing device, you could just place them somewhere outside
"/machine", e.g. directly in the root node or in a container specific to
that use case (/io? /threads?), rather than a new generic bucket of
whatever name. Any objects not under /machine should be close to what
you consider internal.

Note that "info qom-tree" is not the only way to query the objects,
there's some Python QMP scripts as well.

Regards,
Andreas

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