Re: [Qemu-devel] [PATCH v2 2/9] migration: Add announce parameters

[Dr. David Alan Gilbert]

* Daniel P. Berrangé (address@hidden) wrote:
> On Wed, Jan 30, 2019 at 10:32:29AM +0000, Dr. David Alan Gilbert (git) wrote:
> > From: "Dr. David Alan Gilbert" <address@hidden>
> > 
> > Add migration parameters that control RARP/GARP announcement timeouts.
> > 
> > Based on earlier patches by myself and
> >   Vladislav Yasevich <address@hidden>
> > 
> > Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> > ---
> >  hmp.c                    |  28 +++++++++++
> >  include/migration/misc.h |   2 +
> >  include/qemu/typedefs.h  |   1 +
> >  migration/migration.c    | 100 +++++++++++++++++++++++++++++++++++++++
> >  qapi/migration.json      |  54 +++++++++++++++++++--
> >  5 files changed, 182 insertions(+), 3 deletions(-)
> > 
> > diff --git a/qapi/migration.json b/qapi/migration.json
> > index 7a795ecc16..113bb5d925 100644
> > --- a/qapi/migration.json
> > +++ b/qapi/migration.json
> > @@ -6,6 +6,7 @@
> >  ##
> >  
> >  { 'include': 'common.json' }
> > +{ 'include': 'net.json' }
> 
> 
> > @@ -572,6 +588,18 @@
> >  ##
> >  # @MigrateSetParameters:
> >  #
> > +# @announce-initial: Initial delay (in ms) before sending the first 
> > announce
> > +#          (Since 4.0)
> > +#
> > +# @announce-max: Maximum delay (in ms) between packets in the announcment
> > +#          (Since 4.0)
> > +#
> > +# @announce-rounds: Number of self-announce packets sent after migration
> > +#          (Since 4.0)
> > +#
> > +# @announce-step: Increase in delay (in ms) between subsequent packets in
> > +#          the announcement (Since 4.0)
> > +#
> >  # @compress-level: compression level
> >  #
> >  # @compress-threads: compression thread count
> > @@ -653,7 +681,11 @@
> >  # TODO either fuse back into MigrationParameters, or make
> >  # MigrationParameters members mandatory
> >  { 'struct': 'MigrateSetParameters',
> > -  'data': { '*compress-level': 'int',
> > +  'data': { '*announce-initial': 'size',
> > +            '*announce-max': 'size',
> > +            '*announce-rounds': 'size',
> > +            '*announce-step': 'size',
> > +            '*compress-level': 'int',
> >              '*compress-threads': 'int',
> >              '*compress-wait-thread': 'bool',
> >              '*decompress-threads': 'int',
> 
> Historically we've just had a flat list of migration parameters, but
> QAPI doesn't require this. So I wonder about just referencing the
> type you defined in the previous patch:
> 
>    '*announce': 'AnnounceParameters
> 
> from a QMP pov this is trivial & feels more natural. The only downside
> I see is that for HMP it would need to be flattened to what it is here.
> We generally tend to prefer QMP's natural style, even if it doesn't
> match what's nicest for HMP.

I don't trust that's true from QMP; the logic to keep the parameters
optional so that you can set a parameter individually is already pretty
hairy.

Dave

> > @@ -692,6 +724,18 @@
> >  #
> >  # The optional members aren't actually optional.
> >  #
> > +# @announce-initial: Initial delay (in ms) before sending the first 
> > announce
> > +#          (Since 4.0)
> > +#
> > +# @announce-max: Maximum delay (in ms) between packets in the announcment
> > +#          (Since 4.0)
> > +#
> > +# @announce-rounds: Number of self-announce packets sent after migration
> > +#          (Since 4.0)
> > +#
> > +# @announce-step: Increase in delay (in ms) between subsequent packets in
> > +#          the announcement (Since 4.0)
> > +#
> >  # @compress-level: compression level
> >  #
> >  # @compress-threads: compression thread count
> > @@ -769,7 +813,11 @@
> >  # Since: 2.4
> >  ##
> >  { 'struct': 'MigrationParameters',
> > -  'data': { '*compress-level': 'uint8',
> > +  'data': { '*announce-initial': 'size',
> > +            '*announce-max': 'size',
> > +            '*announce-rounds': 'size',
> > +            '*announce-step': 'size',
> 
> Same here about just referencing the AnnounceParameters type.
> 
> > +            '*compress-level': 'uint8',
> >              '*compress-threads': 'uint8',
> >              '*compress-wait-thread': 'bool',
> >              '*decompress-threads': 'uint8',
> 
> Regards,
> Daniel
> -- 
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--
Dr. David Alan Gilbert / address@hidden / Manchester, UK