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Date: Sun, 21 Mar 2010 21:57:00 +0200
From: "Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [Qemu-devel] Re: [PATCH 0/9] Virtio cleanups
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To: Jamie Lokier <jamie@shareable.org>
Cc: qemu-devel@nongnu.org, Juan Quintela <quintela@redhat.com>

On Sun, Mar 21, 2010 at 06:11:43PM +0000, Jamie Lokier wrote:
> Michael S. Tsirkin wrote:
> > That's version 1 of my patch. Version 2 removed even need for macro
> > completely by moving allocations to the caller.
> 
> The downside of moving allocations are: (1) it's one more call in the
> caller, to allocate the type, (2) it needs a virtual destructor for
> each type to free the object, which can clutter the code if there is
> no other reason for virtual destructors.

BTW I don't understand why do you refer to virtual destructors here.
When virtio-net.c allocates and frees structure of type VirtIONet
this is analogous to regular destructur, not a virtual one.

> I don't think those are necessarily bad, but they can remove from the
> neatness of existing code.  Personally I favour an occasional macro
> using sizeof/offsetof/container_of if the result is a natural and
> sensible API to all of its callers.
> 
> -- Jamie