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Subject: Re: [Qemu-devel] [PATCH 21/23] object: sure up reference counting
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To: Anthony Liguori <aliguori@us.ibm.com>
Cc: Peter Maydell <peter.maydell@linaro.org>, Andreas Faerber <andreas.faerber@web.de>, qemu-devel@nongnu.org

On 01/30/2012 10:08 PM, Anthony Liguori wrote:
> Now we have the following behavior:
>
> 1) object_new() returns an object with ref = 1
> 2) object_initialize() does not increase the reference count (ref may be 0).
> 3) object_deref() will finalize the object when ref = 0.  it does not free the
>     memory associated with the object.
> 4) both link and child properties correctly set the reference count.
>
> The expected usage is the following:
>
> 1) child devices should generally be created via object_initialize() using
>     memory from the parent device.  Adding the object as a child property will
>     take ownership of the object and tie the child's life cycle to the parent.
>
> 2) If a child device is created via qdev_create() or some other form of
>     object_new(), there must be an object_delete() call in the parent device's
>     finalize function.

We might want to fix this by adding a special "created as child" 
refcount value, so that the object_delete can still be automatic. 
Adding floating references as they have them in GObject is also 
possible.  I agree that it can be left for later, though.

Paolo