Re: [Qemu-devel] [PATCH V7 2/2] Add a new qmp command to do checkpoint, query xen replication status

[Zhang Chen]

On 02/21/2017 07:15 PM, Markus Armbruster wrote:
> Zhang Chen <address@hidden> writes:
>
> > We can call this qmp command to do checkpoint outside of qemu.
> > Xen colo will need this function.
> I know nothing about "Xen colo", but I'll try anyway.
>
> I *guess* "Xen colo" is a long-running activity, and the new commands
> interact with it.  Correct?

Yes, you are right.
By the way this patch has been reviewed by Eric black.

https://lists.nongnu.org/archive/html/qemu-devel/2017-02/msg03435.html



> > Signed-off-by: Zhang Chen <address@hidden>
> > Signed-off-by: Wen Congyang <address@hidden>
> > ---
> >   migration/colo.c | 17 ++++++++++++++++
> >   qapi-schema.json | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> >   2 files changed, 77 insertions(+)
> >
> > diff --git a/migration/colo.c b/migration/colo.c
> > index 6fc2ade..2f98a33 100644
> > --- a/migration/colo.c
> > +++ b/migration/colo.c
> > @@ -127,6 +127,23 @@ void qmp_xen_set_replication(bool enable, bool primary,
> >       }
> >   }
> >   
> > +ReplicationResult *qmp_query_xen_replication_status(Error **errp)
> > +{
> > +    Error *err = NULL;
> > +    ReplicationResult *result = g_new0(ReplicationResult, 1);
> > +    replication_get_error_all(&err);
> > +    result->status = err ?
> > +                     REPLICATION_STATUS_ERROR :
> > +                     REPLICATION_STATUS_NORMAL;
> Reports only that there is an error, throws away the actual error
> message.  Naive question: could the error message be good to know for
> the QMP user?

Yes, Xen colo will handle it.

> > +    error_free(err);
> > +    return result;
> > +}
> > +
> > +void qmp_xen_do_checkpoint(Error **errp)
> > +{
> > +    replication_do_checkpoint_all(errp);
> > +}
> > +
> >   static void colo_send_message(QEMUFile *f, COLOMessage msg,
> >                                 Error **errp)
> >   {
> > diff --git a/qapi-schema.json b/qapi-schema.json
> > index 9445b93..719744a 100644
> > --- a/qapi-schema.json
> > +++ b/qapi-schema.json
> > @@ -5931,6 +5931,66 @@
> >     'data': { 'enable': 'bool', 'primary': 'bool', '*failover' : 'bool' } }
> >   
> >   ##
> > +# @ReplicationStatus:
> > +#
> > +# Describe the status of replication.
> > +#
> > +# @error: Replication has an error.
> > +#
> > +# @normal: Replication is running normally.
> > +#
> > +# Since: 2.9
> > +##
> > +{ 'enum': 'ReplicationStatus',
> > +  'data': [ 'error', 'normal' ] }
> Do you expect more status values in the future?
>
> If yes, what should clients do when they see a status value they don't
> know?

We will add other status for it, now, that's enough.

> If no, why not simply use bool?
>
> > +
> > +##
> > +# @ReplicationResult:
> > +#
> > +# The result format for 'query-xen-replication-status'.
> > +#
> > +# @status: enum of @ReplicationStatus, which shows current
> > +#          replication error status
> > +#
> > +# Since: 2.9
> > +##
> > +{ 'struct': 'ReplicationResult',
> > +  'data': { 'status': 'ReplicationStatus'} }
> > +
> > +##
> > +# @query-xen-replication-status:
> > +#
> > +# Query replication status while the vm is running.
> > +#
> > +# Returns: A @ReplicationResult objects showing the status.
> > +#
> > +# Example:
> > +#
> > +# -> { "execute": "query-xen-replication-status" }
> > +# <- { "return": { "status": "normal" } }
> > +#
> > +# Since: 2.9
> > +##
> > +{ 'command': 'query-xen-replication-status',
> > +  'returns': 'ReplicationResult' }
> The naming is a bit unfortunate: query-xen-replication-status returns
> ReplicationResult, which contains ReplicationStatus.

I will change the name in next version.

Thanks
Zhang Chen

> > +
> > +##
> > +# @xen-do-checkpoint:
> > +#
> > +# Xen uses this command to notify replication to trigger a checkpoint.
> > +#
> > +# Returns: nothing.
> > +#
> > +# Example:
> > +#
> > +# -> { "execute": "xen-do-checkpoint" }
> > +# <- { "return": {} }
> > +#
> > +# Since: 2.9
> > +##
> > +{ 'command': 'xen-do-checkpoint' }
> > +
> > +##
> >   # @GICCapability:
> >   #
> >   # The struct describes capability for a specific GIC (Generic
>
> .

--
Thanks
Zhang Chen