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From: Paolo Bonzini <pbonzini@redhat.com>
To: "Andreas Färber" <afaerber@suse.de>
Cc: peter.maydell@linaro.org, aliguori@us.ibm.com,
	qemu-devel@nongnu.org, Liu Ping Fan <qemulist@gmail.com>
Subject: Re: [Qemu-devel] [PATCH 1.3 3/5] qom: make object_delete usable for statically-allocated objects
Date: Fri, 23 Nov 2012 18:10:07 +0100	[thread overview]
Message-ID: <50AFADEF.6000905@redhat.com> (raw)
In-Reply-To: <50AFAC11.1050500@suse.de>

Il 23/11/2012 18:02, Andreas Färber ha scritto:
>> Store in the object the freeing function that will be used at deletion
>> > time.  This makes it possible to use object_delete on statically-allocated
>> > (embedded) objects.  Dually, it makes it possible to use object_unparent
>> > and object_unref without leaking memory, when the lifetime of object
>> > might extend until after the call to object_delete.
>> > 
>> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> The code is
> 
> Reviewed-by: Andreas Färber <afaerber@suse.de>
> 
> however I do not agree with the goal in the subject. I thought this was
> to match C++ in actually deallocating the memory.

At the "real" end of the series object_delete disappears completely.  I
posted only the initial part because the rest is not appropriate for
1.3, you can see it at https://github.com/bonzini/qemu/commits/qdev-free.

You just have ref/unref to keep an object alive, and unparent to remove it.

qbus_free and qdev_free become simply synonyms for object_unparent.
After the unparent, the refcount is magically zero for the bus/device
and everything below it in the qtree, and they disappear.

Paolo

  reply	other threads:[~2012-11-23 17:32 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-23  8:47 [Qemu-devel] [PATCH 1.3 0/5] QOM/qdev lifetime fixes Paolo Bonzini
2012-11-23  8:47 ` [Qemu-devel] [PATCH 1.3 1/5] qom: fix refcount of non-heap-allocated objects Paolo Bonzini
2012-11-23 16:49   ` Andreas Färber
2012-11-26 15:49   ` Anthony Liguori
2012-11-26 16:08     ` Paolo Bonzini
2012-11-23  8:47 ` [Qemu-devel] [PATCH 1.3 2/5] qdev: move bus removal to object_unparent Paolo Bonzini
2012-11-23 16:52   ` Andreas Färber
2012-11-27  1:02   ` Andreas Färber
2012-11-23  8:47 ` [Qemu-devel] [PATCH 1.3 3/5] qom: make object_delete usable for statically-allocated objects Paolo Bonzini
2012-11-23 17:02   ` Andreas Färber
2012-11-23 17:10     ` Paolo Bonzini [this message]
2012-11-23  8:47 ` [Qemu-devel] [PATCH 1.3 4/5] qdev: simplify (de)allocation of buses Paolo Bonzini
2012-11-23 17:07   ` Andreas Färber
2012-11-23 17:16     ` Paolo Bonzini
2012-11-23  8:47 ` [Qemu-devel] [PATCH 1.3 5/5] qom: make object_finalize static Paolo Bonzini
2012-11-23 17:12   ` Andreas Färber
2012-11-23 17:32     ` Paolo Bonzini
2012-11-26 21:47 ` [Qemu-devel] [PATCH 1.3 0/5] QOM/qdev lifetime fixes Anthony Liguori

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