Re: [Qemu-devel] [PATCH 7/8] migration: new migration test mode

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Denis V. Lunev (den@openvz.org) wrote:
> From: Igor Redko <redkoi@virtuozzo.com>
> 
> In this patch the ability to start a migration with test-only
> capability was added. It allows to gather the guest VM’s memory
> usage statistics avoiding time and memory overheads and real
> data transmission.  New MIGRATION_STATUS_TEST_COMPLETED was
> added to distinguish between test migration and true migration
> success states.

Why isn't this just a new transport? i.e. I could do this just by doing
a migrate to test:   ?

It seems simpler and avoids some of the special casing?

Dave

> Signed-off-by: Igor Redko <redkoi@virtuozzo.com>
> Reviewed-by: Anna Melekhova <annam@virtuozzo.com>
> Signed-off-by: Denis V. Lunev <den@openvz.org>
> ---
>  migration/migration.c | 12 ++++++++++--
>  qapi-schema.json      |  4 +++-
>  2 files changed, 13 insertions(+), 3 deletions(-)
> 
> diff --git a/migration/migration.c b/migration/migration.c
> index 3182e15..3470d39 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -790,7 +790,9 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
>  
>      s = migrate_init(&params);
>  
> -    if (strstart(uri, "tcp:", &p)) {
> +    if (migrate_is_test()) {
> +        test_start_migration(s, p, &local_err);
> +    } else if (strstart(uri, "tcp:", &p)) {
>          tcp_start_outgoing_migration(s, p, &local_err);
>  #ifdef CONFIG_RDMA
>      } else if (strstart(uri, "rdma:", &p)) {
> @@ -1054,8 +1056,14 @@ static void *migration_thread(void *opaque)
>          }
>  
>          if (qemu_file_get_error(s->file)) {
> -            migrate_set_state(s, MIGRATION_STATUS_ACTIVE,
> +            /*FIXME replace magic number with smth legit*/
> +            if (migrate_is_test() && qemu_file_get_error(s->file) == -42) {
> +                migrate_set_state(s, MIGRATION_STATUS_ACTIVE,
> +                              MIGRATION_STATUS_TEST_COMPLETED);
> +            } else {
> +                migrate_set_state(s, MIGRATION_STATUS_ACTIVE,
>                                MIGRATION_STATUS_FAILED);
> +            }
>              break;
>          }
>  
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 38bf199..e022f9c 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -432,6 +432,8 @@
>  #
>  # @completed: migration is finished.
>  #
> +# @test-completed: migration time estimation finished.
> +#
>  # @failed: some error occurred during migration process.
>  #
>  # Since: 2.3
> @@ -439,7 +441,7 @@
>  ##
>  { 'enum': 'MigrationStatus',
>    'data': [ 'none', 'setup', 'cancelling', 'cancelled',
> -            'active', 'completed', 'failed' ] }
> +            'active', 'completed', 'test-completed', 'failed' ] }
>  
>  ##
>  # @MigrationInfo
> -- 
> 2.1.4
> 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK