Re: [Qemu-devel] Re: [RFD] virtio: Add memory statistics reporting to the balloon driver

[Adam Litke <agl@us.ibm.com>]

On Thu, 2010-01-07 at 16:30 -0200, Luiz Capitulino wrote:
> On Thu, 7 Jan 2010 15:58:30 -0200
> Luiz Capitulino <lcapitulino@redhat.com> wrote:
> 
> >  I like Daniel's idea too. In practice 'refresh-balloon' is going to
> > be Anthony's idea #1 for the QMP case, which seems the right way to
> > do it with QMP.
> 
>  Hm, something that has just occurred to me: it's easy to have
> async messages in the user Monitor, we could add a new type of
> user print callback called async_print.
> 
>  This new callback would be called by the Monitor when the async
> message API is called but we are in user mode.
> 
>  This is really today's user_print, but user data is printed
> asynchronously.

There is one thing I am struggling with as I try to implement this
asynchronous behavior.  How can I suspend the monitor thread to wait for
the stats update to come through?  I see qemu_cond_timedwait(), but that
appears to only be used for a VM's cpu threads.  I also see the bottom
half infrastructure, but I am not sure if that is appropriate either. 

Any pointers would be greatly appreciated.

-- 
Thanks,
Adam