Re: [Xen-devel] HVM Migration of domU on Qemu-upstream DM causes stuck system clock with ACPI

[Diana Crisan <dcrisan@xxxxxxxxxxxx>]

On 31 May 2013, at 11:54, George Dunlap <george.dunlap@xxxxxxxxxxxxx> wrote:

> On 31/05/13 09:34, Diana Crisan wrote:
>> George,
>> On 30/05/13 17:06, George Dunlap wrote:
>>> On 05/30/2013 04:55 PM, Diana Crisan wrote:
>>>> On 30/05/13 16:26, George Dunlap wrote:
>>>>> On Tue, May 28, 2013 at 4:06 PM, Diana Crisan <dcrisan@xxxxxxxxxxxx>
>>>>> wrote:
>>>>>> Hi,
>>>>>> 
>>>>>> 
>>>>>> On 26/05/13 09:38, Ian Campbell wrote:
>>>>>>> On Sat, 2013-05-25 at 11:18 +0100, Alex Bligh wrote:
>>>>>>>> George,
>>>>>>>> 
>>>>>>>> --On 24 May 2013 17:16:07 +0100 George Dunlap
>>>>>>>> <George.Dunlap@xxxxxxxxxxxxx>
>>>>>>>> wrote:
>>>>>>>> 
>>>>>>>>>> FWIW it's reproducible on every host h/w platform we've tried
>>>>>>>>>> (a total of 2).
>>>>>>>>> Do you see the same effects if you do a local-host migrate?
>>>>>>>> I hadn't even realised that was possible. That would have made testing
>>>>>>>> live
>>>>>>>> migrate easier!
>>>>>>> That's basically the whole reason it is supported ;-)
>>>>>>> 
>>>>>>>> How do you avoid the name clash in xen-store?
>>>>>>> Most toolstacks receive the incoming migration into a domain named
>>>>>>> FOO-incoming or some such and then rename to FOO upon completion. Some
>>>>>>> also rename the outgoing domain "FOO-migratedaway" towards the end so
>>>>>>> that the bits of the final teardown which can safely happen after the
>>>>>>> target have start can be done so.
>>>>>>> 
>>>>>>> Ian.
>>>>>> I am unsure what I am doing wrong, but I cannot seem to be able to do a
>>>>>> localhost migrate.
>>>>>> 
>>>>>> I created a domU using "xl create xl.conf" and once it fully booted I
>>>>>> issued
>>>>>> an "xl migrate 11 localhost". This fails and gives the output below.
>>>>>> 
>>>>>> Would you please advise on how to get this working?
>>>>>> 
>>>>>> Thanks,
>>>>>> Diana
>>>>>> 
>>>>>> 
>>>>>> root@ubuntu:~# xl migrate 11 localhost
>>>>>> root@localhost's password:
>>>>>> migration target: Ready to receive domain.
>>>>>> Saving to migration stream new xl format (info 0x0/0x0/2344)
>>>>>> Loading new save file <incoming migration stream> (new xl fmt info
>>>>>> 0x0/0x0/2344)
>>>>>>  Savefile contains xl domain config
>>>>>> xc: progress: Reloading memory pages: 53248/1048575    5%
>>>>>> xc: progress: Reloading memory pages: 105472/1048575   10%
>>>>>> libxl: error: libxl_dm.c:1280:device_model_spawn_outcome: domain 12
>>>>>> device
>>>>>> model: spawn failed (rc=-3)
>>>>>> libxl: error: libxl_create.c:1091:domcreate_devmodel_started: device
>>>>>> model
>>>>>> did not start: -3
>>>>>> libxl: error: libxl_dm.c:1311:libxl__destroy_device_model: Device Model
>>>>>> already exited
>>>>>> migration target: Domain creation failed (code -3).
>>>>>> libxl: error: libxl_utils.c:393:libxl_read_exactly: file/stream
>>>>>> truncated
>>>>>> reading ready message from migration receiver stream
>>>>>> libxl: info: libxl_exec.c:118:libxl_report_child_exitstatus: migration
>>>>>> target process [10934] exited with error status 3
>>>>>> Migration failed, resuming at sender.
>>>>>> xc: error: Cannot resume uncooperative HVM guests: Internal error
>>>>>> libxl: error: libxl.c:404:libxl__domain_resume: xc_domain_resume
>>>>>> failed for
>>>>>> domain 11: Success
>>>>> Aha -- I managed to reproduce this one as well.
>>>>> 
>>>>> Your problem is the "vncunused=0" -- that's instructing qemu "You must
>>>>> use this exact port for the vnc server".  But when you do the migrate,
>>>>> that port is still in use by the "from" domain; so the qemu for the
>>>>> "to" domain can't get it, and fails.
>>>>> 
>>>>> Obviously this should fail a lot more gracefully, but that's a bit of
>>>>> a lower-priority bug I think.
>>>>> 
>>>>>  -George
>>>> Yes, I managed to get to the bottom of it too and got vms migrating on
>>>> localhost on our end.
>>>> 
>>>> I can confirm I did get the clock stuck problem while doing a localhost
>>>> migrate.
>>> 
>>> Does the script I posted earlier "work" for you (i.e., does it fail after 
>>> some number of migrations)?
>> 
>> I left your script running throughout the night and it seems that it does 
>> not always catch the problem. I see the following:
>> 
>> 1. vm has the clock stuck
>> 2. script is still running as it seems the vm is still ping-able.
>> 3. migration fails on the basis that the vm is does not ack the suspend 
>> request (see below).
> 
> So I wrote a script to run "date", sleep for 2 seconds, and run "date" a 
> second time -- and eventually the *sleep* hung.
> 
> The VM is still responsive, and I can log in; if I type "date" manually 
> successive times then I get an advancing clock, but if I type "sleep 1" it 
> just hangs.
> 
> If you run "dmesg" in the guest, do you see the following line?
> 
> CE: Reprogramming failure. Giving up
> 

I do. It is preceded by:
CE: xen increased min_delta_ns to 4000000 nsec

> -George

--
Diana
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