Re: [Qemu-devel] [PATCH v9 05/10] move out net queue structs define

[Yang Hongyang <yanghy@cn.fujitsu.com>]

On 09/07/2015 07:00 PM, Daniel P. Berrange wrote:
> On Mon, Sep 07, 2015 at 06:53:49PM +0800, Yang Hongyang wrote:
>> On 09/07/2015 05:11 PM, Stefan Hajnoczi wrote:
>> [...]
>>>> Thanks very much for the suggestion, I've already implemented it and tested,
>>>> the code looks cleaner now.
>>>>
>>>> The last issue is the QOM thing, do Markus and Andreas have more input
>>>> about that?
>>>
>>> If you would like to see examples of QOM usage, take a look at
>>> iothread.c and/or backends/hostmem.c.
>>>
>>> The key things are:
>>>
>>> 1. They use include/qom/object.h to register a type based on
>>>     TYPE_OBJECT and their properties are registered using
>>>     object_property_add_*().
>>>
>>> 2. They implement the TYPE_USER_CREATABLE interface so the -object
>>>     command-line option can be used to instantiate them.  See
>>>     object_interfaces.h.
>>>
>>> As a result, a lot of code becomes unnecessary and iothread.c, in
>>> particular, is quite short.
>>
>> After looking into this, I have some questions on the implement, could you
>> please help me on this because I don't know much about the object mechanism:
>>
>> The netfilter need to be initialized after the net_init_clients, because we
>> need to attach the filter to the net client. But currently, net client is not
>> using QOM, and seems that it is initialized after objects been created. So here
>> comes the problem: how can I initialize a certain object later, is it possiable?
>
> It is currently a bit hacky - most objects are initialized very early,
> but we have a similar problem with rng-egd which must be created /after/
> chardevs. To deal with this in vl.c main() we have two helper methods
> object_create_initial and object_create_delayed. The delayed method though
> still happens before the net clients are created. We could probably just
> move the objec_create_delayed method invokation to later on, after net
> clients are created, but if that doesn't work just add an extra helper
> object_create_very_delayed :-)

If it's ok to move creation of "rng-egd" later, then "move the
objec_create_delayed method invokation after net clients are created" should
solve the problem.

Thank you for the help!

>
> Regards,
> Daniel
>

-- 
Thanks,
Yang.