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Date: Tue, 18 Dec 2012 10:47:37 -0500
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: "Liu, Jinsong" <jinsong.liu@intel.com>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH V1 1/2] Xen acpi memory hotplug driver
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> >>>> Not only inform firmware.
> >>>> Hotplug notify callback will invoke acpi_bus_add -> ... ->
> >>>> implicitly invoke drv->ops.add method to add the hotadded memory
> >>>> device.
> >>> 
> >>> Gotcha.
> >> 
> >> ? So it will lose the notification and no way to add the new memory
> >> device in the future. 
> >> 
> >> Xen memory hotplug logic consist of 2 parts:
> >> 1) driver logic (.add/.remove etc)
> >> 2) notification install/callback logic
> >> If you want to use 'xen_stub driver + .add/.remove ops', then
> >> notification install/callback logic would implement with xen_stub
> >> driver (means in build-in part, otherwise it would lose notification
> >> when the ops unload) --> but that would make xen_stub in big build-in
> >> size.
> > 
> > How about
> > * build-in part: xen_stub driver (stub .add to record what matched
> > cpu devices) + notification install/callback; 
> > * module part: .add/.remove ops;
> > w/ it, native driver has no chance to load and no hotplug event lose,
> > and approximately 1/3 code is build-in and 2/3 are module. 
> > 
> > I think it will work but I'm not quite sure, at least we can have a
> > try/test? 
> > 
> > Thanks,
> > Jinsong
> > 
> 
> Thoughts? If you think it's OK, I will update later.

Pls try. I am just thinking that the less we of code that has to be built-in - the
better.
> 
> Thanks,
> Jinsong