Re: Xend transaction reduction breaks migration

["Daniel P. Berrange" <berrange@redhat.com>]

On Wed, Nov 14, 2007 at 11:44:42PM +0000, Keir Fraser wrote:
> Hey Daniel,
> 
> It turns out that your changeset 16260 in xen-unstable breaks our localhost
> non-live migration tests. What happens is that randomly (but fairly often)
> xend will throw an assertion at line 'assert console_port' in
> XendCheckpoint.py. This is in the domain_restore_fd context, so result is
> that the restorer dies and then of course the saver fails soon after since
> the migration socket goes away.
> 
> Any idea how your patch could cause this rather bizarre behaviour? I haven't
> worked it out myself, though I'm 99% sure it *is* that changeset that has
> caused this regression (based on tests with the changeset reverted).

Basically, instead of doing many small transactions, my change made some stuff
all happen in one large transaction. Oddly though, I tried to be careful so
that I only changed the codepath for the 'xm list' operation (well the SEXPR
call to the list operation). Other operations like create, save, restore
ought to be left using fine grained transactions as before.

Dan.
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