Using dm-ioband with Xen

Using dm-ioband with Xen

[Thomas Goirand]

Hi,

It's been many years that I've been looking at the dm-ioband patch for
Linux, which is great.

While having a /etc/dm-ioband.conf is great, I think it would be even
better if we had this control in a Xen domU configuration file, if
dm-ioband is installed and running.

Or is there plans to have the type of feature that dm-ioband offers be
directly in Xen? Does one of you know why dm-ioband doesn't seem to be
in the mainline kernel as well?

What do you think?

Thomas

Re: Using dm-ioband with Xen

[Konrad Rzeszutek Wilk]

On Tue, Dec 28, 2010 at 02:48:25PM +0800, Thomas Goirand wrote:
> Hi,
> 
> It's been many years that I've been looking at the dm-ioband patch for
> Linux, which is great.
> 
> While having a /etc/dm-ioband.conf is great, I think it would be even
> better if we had this control in a Xen domU configuration file, if
> dm-ioband is installed and running.
> 
> Or is there plans to have the type of feature that dm-ioband offers be
> directly in Xen? Does one of you know why dm-ioband doesn't seem to be
> in the mainline kernel as well?

I would suggest you ping the authors of it and see what happend?

I recall discussions about cgroups being able to do something akin to it,
but I don't remember the details anymore..

Re: Using dm-ioband with Xen

[Ian Campbell]

On Mon, 2011-01-03 at 16:52 +0000, Konrad Rzeszutek Wilk wrote:
> On Tue, Dec 28, 2010 at 02:48:25PM +0800, Thomas Goirand wrote:
> > Hi,
> > 
> > It's been many years that I've been looking at the dm-ioband patch for
> > Linux, which is great.
> > 
> > While having a /etc/dm-ioband.conf is great, I think it would be even
> > better if we had this control in a Xen domU configuration file, if
> > dm-ioband is installed and running.
> > 
> > Or is there plans to have the type of feature that dm-ioband offers be
> > directly in Xen? Does one of you know why dm-ioband doesn't seem to be
> > in the mainline kernel as well?
> 
> I would suggest you ping the authors of it and see what happend?

Agreed. I think we really need to understand why a given solution has
not been accepted upstream e.g. what problems it has or what the
preferred upstream alternatives are before adding out of tree kernel
dependencies to Xen toolstacks etc.

In particular the barrier to accepting support for out of tree stuff
which isn't at least moving in the direction of upstream should be
considered very high.

> I recall discussions about cgroups being able to do something akin to it,
> but I don't remember the details anymore..

I vaguely recall this too. I thought it was discussed at LPC in November
but the only reference I can find is a few bullet points in the kernel
report slides.
(http://www.linuxplumbersconf.org/2010/ocw/proposals/417 /
http://www.linuxplumbersconf.org/2010/ocw//system/presentations/417/original/kreport.pdf)

I also found Documentation/cgroups/blkio-controller.txt in 2.6.37-rc
which looks promising.

Ian.