Re: [Xen-devel] [PATCH] xc_save: ignore the first suspend event channel notification

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 8/9/08 23:36, "Brendan Cully" <brendan@xxxxxxxxx> wrote:

>> I checked in your patch as is. One question: do we need the
>> wait-one-second-for-shutdown loop in suspend_and_state() at all? My reading
>> of (*suspend)() is that it should be sure the domain is suspended when it
>> returns, and hence should suspend_and_state() not simply raise an error if
>> it finds that domaininfo does not indicate the guest is shut down? The retry
>> loop may simply be allowing bugs of the sort you've just fixed to linger.
> 
> I agree that that retry loop is a bit dubious. It appears to come from
> changeset 2147:949f21fc9e77 (Fix migrate to cope with domains that are
> paused.) This was long before device migration appeared in xend
> (changeset 9657:1fe63743a147), when the only thing that mattered was
> that the domain be suspended before the final round.
> 
> Removing the poll in suspend_and_state undoes 2147. If we want to keep
> that logic, we could probably just hoist it up into *suspend.

If the domain is paused then we're boned, since the evtchn will never fire /
we won't get shutdown acknowledgement from xend. The subsequent checks in
suspend_and_state() are too late. So, if you revert 2147 does everything
still work okay? If so we should do that.

 -- Keir



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