Re: [Qemu-devel] [PATCH 00/39] Delay destruction of memory regions to instance_finalize

[Michael S. Tsirkin]

On Wed, Jun 05, 2013 at 10:33:05AM -0500, Anthony Liguori wrote:
> "Michael S. Tsirkin" <address@hidden> writes:
> 
> > On Wed, Jun 05, 2013 at 07:53:05AM -0500, Anthony Liguori wrote:
> >> "Michael S. Tsirkin" <address@hidden> writes:
> >> 
> >> > On Wed, Jun 05, 2013 at 11:50:52AM +0200, Andreas Färber wrote:
> >> >> Am 04.06.2013 20:51, schrieb Paolo Bonzini:
> >> >> > This series changes all PCI devices (the sole to support hotplug
> >> >> > _and_ use MemoryRegions) to do memory_region_del_subregion at
> >> >> > unrealize time, and memory_region_destroy at instance_finalize
> >> >> > time.
> >> >> 
> >> >> The general idea looks good.
> >> >> 
> >> >> Could you please follow-up with a patch that switches from exit to
> >> >> unrealize?
> >> >
> >> > What do you guys think about changing the name to something
> >> > else e.g. "free" or "destroy"?
> >> 
> >> exit/unrealize != free/destroy.
> >> 
> >> You don't actually free anything.  See 00/39 in this series for a
> >> precise description.
> >
> > That's where I got this. It says:
> > "instance_finalize will reclaim the memory"
> 
> I'm not sure what you're talking about.
> 
> There are two callbacks: exit and instance_finalize.
> 
> exit() is called to disconnect the device to the guest.  Andreas is
> proposing renaming it to unrealize.
> 
> Ideally, reset() would be implemented as a combination of calls to
> unrealize() + realize() (or exit() + init() as they are named today).
> 
> Nothing should be freed in exit.
> 
> instance_finalize is only called once, before the object is freed().  It
> should be used to release resources associated with the object.
> 
> Paolo is using this to destroy memory regions.  Normally this callback
> is never used because child objects are automatically handled by QOM.
>
> "finalize" is the standard name of the hook that gets called before
> garbage collection as Andreas previously pointed out.

I am simply asking for function names to tell us
what they do, not when they are called.

>  It's this way in
> Java, Python, C#, etc.

Well bringing in idioms from more languages just serves to confuse
readers even more.

> Regards,
> 
> Anthony Liguori
> 
> >
> >> > http://dictionary.cambridge.org/spellcheck/american-english/?q=unrealize
> >> 
> >> English is a fluid language.  I wouldn't worry too much about that.
> >> 
> >> Regards,
> >> 
> >> Anthony Liguori
> >
> > Well I am not worried about English at all.
> > I'm just confused by the function naming, and
> > I think it can be improved.
> >
> > Can we have names actually say what a function is
> > doing? There's no need to use ambiguous terms and then
> > document what they mean.
> >
> >
> >> > I can do it easily if people agree.
> >> >
> >> >> use BUS(), PCI_DEVICE() etc. to hide this.
> >> >> 
> >> >> Andreas
> >> >> 
> >> >> -- 
> >> >> SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
> >> >> GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg