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Date: Tue, 15 Jun 2010 11:42:58 -0500
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] [CFR 1/10] qmp: balloon command
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Cc: Luiz Capitulino <lcapitulino@redhat.com>, qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>, Markus Armbruster <armbru@redhat.com>

On 06/15/2010 11:30 AM, Anthony Liguori wrote:
> balloon
> -------
>
> Request VM to change its memory allocation (in bytes).
>    

We ought to clarify a few points:

1) What happens if there isn't a balloon device?
2) What happens upon reboot?
3) What is the valid range for value?
4) How does a user determine when the guest has actually responded to 
the balloon request?

This is a case where I think we ought to use async events because the 
guest can adjust it's balloon allotment without an explicit request from 
the host.  In fact, if we add a shrinker callback to the balloon driver 
(and we should) it will do exactly this.

Regards,

Anthony Liguori

> Arguments:
>
> - "value": New memory allocation (json-int)
>
> Example:
>
> ->  { "execute": "balloon", "arguments": { "value": 536870912 } }
> <- { "return": {} }
>
>
>