Re: Balloon driver.

[Christoph Egger <Christoph_Egger%gmx.de@localhost>]

On Wednesday 07 July 2010 10:48:59 Cherry G. Mathew wrote:
> On 7 July 2010 14:00, Christoph Egger <Christoph_Egger%gmx.de@localhost> 
> wrote:
> > On Tuesday 06 July 2010 17:02:08 Cherry G. Mathew wrote:
> >> On 6 July 2010 09:19, Cherry G. Mathew 
> >> <cherry.g.mathew%gmail.com@localhost> wrote:
> >> > jym@ and I made a few more changes to this.
> >> > Have a look here:
> >> > ftp://ftp.netbsd.org/pub/NetBSD/misc/cherry/balloon/
> >> >
> >> > Any feedback would be much appreciated. If things go well, I'm hoping
> >> > to commit this marked "EXPERIMENTAL" "soon".
> >>
> >> Done.
> >
> > Thank you for doing this work.
> >
> > Though I have to report a bug:
> >
> > I have an amd64 Dom0 kernel w/o XEN_BALLOONING in the kernel config.
> > Boot the xen kernel with dom0_mem=512m
> >
> > After login I do:
> >
> > # sysctl kern.xen
> > kern.xen.balloon.current = 131072
> > node_val out of range.
> > node_val = 0
> >
> > I expect kern.xen.balloon.current to say 512MB and I don't expect to see
> > the node_val messages.
>
> Whoops!
>
> Does the following patch fix it for you:

I think, the ballooning sysctl's should be always there regardless if compiled
with or w/o XEN_BALLOONING in the kernel config to prevent misbehaviour
of the xen tools.

If XEN_BALLOONING is not specified then the sysctl values should be
a) read-only
b) print reasonable fixed values.

Christoph