Re: [Qemu-devel] [PULL 24/28] migration: Make events a capability

[Wen Congyang <ghostwcy@gmail.com>]

At 2015/7/7 21:09, Juan Quintela Wrote:
> Make check fails with events.  THis is due to the parser/lexer that it
> uses.  Just in case that they are more broken parsers, just only send
> events when there are capabilities.
> 
> Signed-off-by: Juan Quintela <quintela@redhat.com>
> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
>   include/migration/migration.h |  1 +
>   migration/migration.c         | 20 ++++++++++++++++++--
>   qapi-schema.json              |  5 ++++-
>   3 files changed, 23 insertions(+), 3 deletions(-)
> 
> diff --git a/include/migration/migration.h b/include/migration/migration.h
> index a308ecc..b2711ef 100644
> --- a/include/migration/migration.h
> +++ b/include/migration/migration.h
> @@ -177,6 +177,7 @@ bool migrate_use_compression(void);
>   int migrate_compress_level(void);
>   int migrate_compress_threads(void);
>   int migrate_decompress_threads(void);
> +bool migrate_use_events(void);
> 
>   void ram_control_before_iterate(QEMUFile *f, uint64_t flags);
>   void ram_control_after_iterate(QEMUFile *f, uint64_t flags);
> diff --git a/migration/migration.c b/migration/migration.c
> index d8415c4..cd32eac 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -205,6 +205,14 @@ void register_global_state(void)
>       vmstate_register(NULL, 0, &vmstate_globalstate, &global_state);
>   }
> 
> +static void migrate_generate_event(int new_state)
> +{
> +    if (migrate_use_events()) {
> +        qapi_event_send_migration(new_state, &error_abort);
> +        trace_migrate_set_state(new_state);
> +    }
> +}
> +
>   /*
>    * Called on -incoming with a defer: uri.
>    * The migration can be started later after any parameters have been
> @@ -511,8 +519,7 @@ void qmp_migrate_set_parameters(bool has_compress_level,
>   static void migrate_set_state(MigrationState *s, int old_state, int new_state)
>   {
>       if (atomic_cmpxchg(&s->state, old_state, new_state) == old_state) {
> -        qapi_event_send_migration(new_state, &error_abort);
> -        trace_migrate_set_state(new_state);
> +        migrate_generate_event(new_state);

Why moving trace_* to migrate_generate_event()? trace event should be
controlled
by the monitor command trace-event xxx on/off. It is very strange if the
user turns
the trace event on, but gets no output.

Thanks
Wen Congyang

>       }
>   }
> 
> @@ -862,6 +869,15 @@ int migrate_decompress_threads(void)
>       return s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS];
>   }
> 
> +bool migrate_use_events(void)
> +{
> +    MigrationState *s;
> +
> +    s = migrate_get_current();
> +
> +    return s->enabled_capabilities[MIGRATION_CAPABILITY_EVENTS];
> +}
> +
>   int migrate_use_xbzrle(void)
>   {
>       MigrationState *s;
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 106008c..1285b8c 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -523,6 +523,9 @@
>   #          minimize migration traffic. The feature is disabled by default.
>   #          (since 2.4 )
>   #
> +# @events: generate events for each migration state change
> +#          (since 2.4 )
> +#
>   # @auto-converge: If enabled, QEMU will automatically throttle down the guest
>   #          to speed up convergence of RAM migration. (since 1.6)
>   #
> @@ -530,7 +533,7 @@
>   ##
>   { 'enum': 'MigrationCapability',
>     'data': ['xbzrle', 'rdma-pin-all', 'auto-converge', 'zero-blocks',
> -           'compress'] }
> +           'compress', 'events'] }
> 
>   ##
>   # @MigrationCapabilityStatus
>