Re: [Hackathon Minutes] Xen 4.4 Planning

[Alex Bligh <alex@alex.org.uk>]

Ian,

--On 14 June 2013 00:56:14 +0100 Ian Murray <murrayie@yahoo.co.uk> wrote:

> When you talk about "stuff" breaking between major releases, are you
> talking about Xen code not functioning or your code failing because of
> changes in Xen? If the latter, are we talking designed changes in Xen's
> behaviour or non-designed ones (=bugs)?

Both.

As an example of the first, the API changed very significantly between
3.x and 4.1, and 4.1 and 4.2. Some of the API changes were subtle (e.g.
what you had to do across a fork()).

As an example of the second, see the very long thread with O_DIRECT
in the subject line.

> I am at a loss as to what is wrong with contributing a few bug fixes back
> if you're technically capable of finding and fixing... I am not feeling
> the community spirit here.

There's nothing wrong with that, and we have done. However this thread
is about development cycles. Critical stuff breaks, we know that.
That should happen in the unstable version. Patches that fix critical
stuff should be made in the unstable version, not the stable version.

> Also, a little bit of Googling tells me that Flexiant (that is the "we"
> in all of this, right?) provides cloud software to third-parties and does
> not provide cloud services itself. To make your product work reliably
> with Xen for your customers, are you distributing your own patches for
> Xen to these third-parties?

Yes. We ship with a patched version of xen. All our patches have been sent
here and are on github. If the implication is that we're somehow keeping
these to ourselves, you have that totally wrong. We would like nothing
better than all our patches to be in mainline. For 4.2 we are currently
carrying one patch for fixing the tsc (see 'clock stalled on live
migration') which is a backport of a 4.3 patch here, and my minideb
patch which is a packaging change which (for quite understandable
reasons) people don't want in mainline. In the past, we've carried
tens of patches - see the live migrate on qemu-upstream-dm for 4.2
patch series I posted here, since accepted.

-- 
Alex Bligh