Re: [Xen-devel] [PATCH 0 of 5] xl shutdown compatibility with xm

[Sander Eikelenboom <linux@xxxxxxxxxxxxxx>]

Monday, October 15, 2012, 1:45:33 PM, you wrote:

> On Mon, 2012-10-15 at 12:21 +0100, Sander Eikelenboom wrote:
>> Monday, October 15, 2012, 12:37:57 PM, you wrote:
>> 
>> > On Mon, 2012-10-15 at 11:32 +0100, Sander Eikelenboom wrote:
>> >> Hi Ian,
>> >> 
>> >> Great thanks !
>> >> Only thing i was wondering about:
>> >> 
>> >> Shouldn't the "-F" option be dropped in favour of always trying the
>> >> "acpi fallback" when the pv shutdown fails.
>> >> 
>> >> This because the shutdown scripts still don't work for domains without
>> >> pv shutdown and i don't see a down side to just trying that as
>> >> fallback.
>> 
>> > It is guess OS dependent what the ACPI button press event does, it can
>> > reboot, shutdown or hibernate etc depending on the OS type and its
>> > configuration. (in theory I suppose it is completely arbitrary e.g. it
>> > could be configured to eject the CD-ROM or something equally random).
>> 
>> > Therefore the user needs to be aware of when they can safely use it.
>> 
>> Well yes and no:
>>     - can't remember having (to make) that choice with xm ?

> Looks like xend uses SCHEDOP_remote_shutdown. It's unclear to me why
> this is better than just shooting the domain with destroy...

>>     - On shutdown with xl as toolstack and when the guest doesn't
>> support pv shutdown, the init.d/xendomains script doesn't even attempt
>> to shutdown this guest by acpi fallback.
>>     - As a result when using xl as toolstack, the guest is terminated
>> non gracefully when the whole machine finally shutsdown, which seems
>> less desirable then at least *trying* to shut it down gracefully by
>> using the acpi button.

> Using the ACPI fallback is a decision which can only be made locally
> with full knowledge of the configuration of the guests.

I'm not totally convinced (yet):
  - In case of a system shutdown, it seems better to at least *try* instead of 
just halting the system without shutting such a guest down.
      For the shutdown scripts the problems is that there is no way to give it 
the "full knowledge" of how to shutdown a particular guest.
      It would be possible to use the -F flag in the sysconfig xendomains file, 
since the pv shutdown is always tried first.

  - Not everyone seems to be aware, say an IanJ ;-)
      Under the assumption that the guests in the xen-test-harness do react in 
the right way to a acpi powerbutton event,
      it seems the "never passes" in  "Guest-stop" row of 
http://www.chiark.greenend.org.uk/~xensrcts/logs/13967/
      Will probably pass when the -F option will be used, see 
http://www.chiark.greenend.org.uk/~xensrcts/logs/13967/test-amd64-i386-xl-win7-amd64/13.ts-guest-stop.log

--
Sander

> Ian.




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