Re: [PATCH v6 00/11] libxl: ocaml: improve the bindings

[George Dunlap <george.dunlap@eu.citrix.com>]

On 12/10/2013 01:20 PM, Ian Campbell wrote:
> On Mon, 2013-12-09 at 15:17 +0000, Rob Hoes wrote:
>> This series contains version 6 of the remaining patches to fix the OCaml
>> bindings to libxl.
>>
>> The main change compared to version 5 is that we now properly register the
>> "user" values (OCaml values that are given to the libxl event system, and
>> returned to OCaml in callbacks) with the OCaml GC.
> So the release process has moved on sufficiently that I think we need to
> consider whether the previous release-ack still stands:
> http://thread.gmane.org/gmane.comp.emulators.xen.devel/180254/focus=180383
>
> I think the arguments made there still stand, in short it would be
> awesome if xapi could move to using libxl on top of 4.4 and the risks
> are almost entirely contained within this use case, which cannot be
> satisfied by the code as it stands today.

Except that that basically calls into question what a "code freeze" is 
at all.  At some point we just need to say, "No more, this is what we 
have; from now on we work on bug fixes."

We've decided that PVH dom0 and ARM "physical address space leak" fixes 
are blockers for strategic reasons.  Is there a good reason that we 
should consider updated OCaml bindings in the same light?

At this point, the fact that there is only one downstream user 
(XenServer) is an argument *against* its inclusion: there is very little 
benefit, as XS can simply carry the patches if they want to.

The timeframe in which we did this kind of "cost/benefits" analysis for 
new features was meant to have passed already -- the "grace period" has 
already been three weeks; the schedule for the code freeze has been 
published and hasn't changed in 6 weeks.

While I can certainly understand the feeling of "just having missed" 
when it might have been accepted, given the number of people working on 
Xen now, I think we are almost always going to be in that situation.  We 
can either keep slipping the window until we happen to get lucky enough 
not to have any "really nice" features to add in, or we can set a hard 
deadline and say, "Sorry, that will have to wait."  Feel free to make a 
case for the first, but at the moment the second seems like the only way 
to proceed to me.

  -George