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Date: Tue, 11 Dec 2012 17:23:55 -0200
From: Luiz Capitulino <lcapitulino@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 0/3] re-enable balloon stats
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To: Dietmar Maurer <dietmar@proxmox.com>
Cc: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, "aliguori@us.ibm.com" <aliguori@us.ibm.com>, mdroth <mdroth@linux.vnet.ibm.com>, "agl@us.ibm.com" <agl@us.ibm.com>

On Tue, 11 Dec 2012 19:07:48 +0000
Dietmar Maurer <dietmar@proxmox.com> wrote:

> > I could move the check for the stats feature bit from the function that
> > enables polling to the timer callback. This would solve Dietmar's use-case,
> 
> that would be great.
> 
> > but it would silently fail if the feature is never negotiated (as you said
> > above).
> 
> Why don't we raise the error when we query the values?

Hmm, that's a good idea.

Only small nit is that, today old stats will remain available to be queried
even if you disable the timer. If we do what you suggest, old stats won't
be available if the module is unloaded (well, I *guess* the guest will unset
the feature bit on module removal).