Re: [PATCH v2] iotests.py: Let wait_migration wait even more

[Kevin Wolf <kwolf@redhat.com>]

Am 19.12.2019 um 19:36 hat Max Reitz geschrieben:
> The "migration completed" event may be sent (on the source, to be
> specific) before the migration is actually completed, so the VM runstate
> will still be "finish-migrate" instead of "postmigrate".  So ask the
> users of VM.wait_migration() to specify the final runstate they desire
> and then poll the VM until it has reached that state.  (This should be
> over very quickly, so busy polling is fine.)
> 
> Without this patch, I see intermittent failures in the new iotest 280
> under high system load.  I have not yet seen such failures with other
> iotests that use VM.wait_migration() and query-status afterwards, but
> maybe they just occur even more rarely, or it is because they also wait
> on the destination VM to be running.
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>

> diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
> index 13fd8b5cd2..0b62c42851 100644
> --- a/tests/qemu-iotests/iotests.py
> +++ b/tests/qemu-iotests/iotests.py
> @@ -668,12 +668,16 @@ class VM(qtest.QEMUQtestMachine):
>              }
>          ]))
>  
> -    def wait_migration(self):
> +    def wait_migration(self, expect_runstate):
>          while True:
>              event = self.event_wait('MIGRATION')
>              log(event, filters=[filter_qmp_event])
>              if event['data']['status'] == 'completed':
>                  break
> +        # The event may occur in finish-migrate, so wait for the expected
> +        # post-migration runstate

That's a bit too specific now that you have expect_runstate.

> +        while self.qmp('query-status')['return']['status'] != expect_runstate:
> +            pass
>  
>      def node_info(self, node_name):
>          nodes = self.qmp('query-named-block-nodes')

Tested-by: Kevin Wolf <kwolf@redhat.com>