Re: [Qemu-devel] [RFC v4 16/21] blockjobs: add waiting status

[Eric Blake]

On 02/23/2018 05:51 PM, John Snow wrote:
> For jobs that are stuck waiting on others in a transaction, it would
> be nice to know that they are no longer "running" in that sense, but
> instead are waiting on other jobs in the transaction.
>
> Jobs that are "waiting" in this sense cannot be meaningfully altered
> any longer as they have left their running loop. The only meaningful
> user verb for jobs in this state is "cancel," which will cancel the
> whole transaction, too.
>
> Transitions:
> Running -> Waiting:   Normal transition.
> Ready   -> Waiting:   Normal transition.
> Waiting -> Aborting:  Transactional cancellation.
> Waiting -> Concluded: Normal transition.
>
> Removed Transitions:
> Running -> Concluded: Jobs must go to WAITING first.
> Ready   -> Concluded: Jobs must go to WAITING fisrt.

s/fisrt/first/

> +++ b/blockjob.c

> @@ -3934,6 +3938,29 @@
>               'offset': 'int',
>               'speed' : 'int' } }
>   
> +##
> +# @BLOCK_JOB_WAITING:
> +#
> +# Emitted when a block job that is part of a transction has stopped work and is

s/transction/transaction/

> +# waiting for other jobs in the transaction to reach the same state.

Is this event emitted only for 'new-style' transactions (old drivers 
will never see it, because they don't request new style), or always (old 
drivers will see, but presumably ignore, it)?

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org