Re: [Xen-devel] [xen-unstable test] 128240: regressions - FAIL

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Mon, Oct 01, 2018 at 04:19:07PM +0100, George Dunlap wrote:
> On 10/01/2018 04:17 PM, Wei Liu wrote:
> > On Mon, Oct 01, 2018 at 09:10:25AM -0600, Jan Beulich wrote:
> >>>>> On 01.10.18 at 16:33, <wei.liu2@xxxxxxxxxx> wrote:
> >>> On Mon, Oct 01, 2018 at 03:04:02AM -0600, Jan Beulich wrote:
> >>>>>>> On 30.09.18 at 23:59, <osstest-admin@xxxxxxxxxxxxxx> wrote:
> >>>>> flight 128240 xen-unstable real [real]
> >>>>> http://logs.test-lab.xenproject.org/osstest/logs/128240/ 
> >>>>>
> >>>>> Regressions :-(
> >>>>>
> >>>>> Tests which did not succeed and are blocking,
> >>>>> including tests which could not be run:
> >>>>>  test-amd64-amd64-migrupgrade 22 guest-migrate/src_host/dst_host fail 
> >>>>> REGR. vs. 
> >>> 128084
> >>>>
> >>>> At the first glance
> >>>>
> >>>> libxl: error: libxl_sched.c:232:sched_credit_domain_set: Domain 
> >>>> 1:Getting 
> >>> domain sched credit: Invalid argument
> >>>> libxl: error: libxl_create.c:1275:domcreate_rebuild_done: Domain 
> >>>> 1:cannot 
> >>> (re-)build domain: -3
> >>>>
> >>>> might indicate a problem resulting from the switch to credit2 as the 
> >>>> default
> >>>> scheduler. But "first glance" here really means what it says - I didn't 
> >>>> look
> >>>> (yet) at what exactly libxl tries to do there, in the hope that others 
> >>>> may
> >>>> know without much digging.
> >>>
> >>> I think this is due to toolstack trying to set the same scheduler
> >>> parameters for the newly created guest.
> >>>
> >>> But in this test, the destination host is using a different scheduler
> >>> from the source host. Asking for credit scheduler on a credit2 host is
> >>> wrong.
> >>>
> >>> The relevant snippet in guest cfg (JSON) is:
> >>>
> >>>                 "sched_params": {
> >>>                     "sched": "credit",
> >>>                     "weight": 256,
> >>>                     "cap": 0
> >>>                 },
> >>>
> >>> I can't think of a method to fix it off the top of my head though.
> >>
> >> So is this something that was specified in the original config? Or
> >> is it just the current value which gets read and an attempt made
> >> to re-install. If there was no explicit setting in the guest config,
> >> shouldn't such a "default" setting be retained by not transferring
> >> any scheduler specifics during migration?
> >>
> > 
> > No setting in guest cfg. Those values are extracted from the hypervisor.
> > I think we may be able to not send default values to the remote end.
> 
> Wait, the migration code reads the scheduler parameters -- even if these
> have not been explicitly set by the admin -- and sends them along with
> the migration stream?  And if the remote scheduler is different, the
> migration fails?
> 
> That's not so good. :-)

But one can argue that the guest is specific configured that way so it's
parameters should be preserved. We normally analyse things on a case by
case basis.

Wei.

> 
>  -George
> 

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel