Re: [Qemu-devel] [PATCH 01/13] migration: create Migration Incoming State at init time

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

* Juan Quintela (quintela@redhat.com) wrote:
> Signed-off-by: Juan Quintela <quintela@redhat.com>
> ---
>  include/migration/migration.h |  1 -
>  migration/migration.c         | 38 +++++++++++++++++---------------------
>  migration/savevm.c            |  4 ++--
>  3 files changed, 19 insertions(+), 24 deletions(-)
> 
> diff --git a/include/migration/migration.h b/include/migration/migration.h
> index 2791b90..37ef4f2 100644
> --- a/include/migration/migration.h
> +++ b/include/migration/migration.h
> @@ -112,7 +112,6 @@ struct MigrationIncomingState {
>  };
> 
>  MigrationIncomingState *migration_incoming_get_current(void);
> -MigrationIncomingState *migration_incoming_state_new(QEMUFile *f);
>  void migration_incoming_state_destroy(void);
> 
>  /*
> diff --git a/migration/migration.c b/migration/migration.c
> index 4d417b7..a71921f 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -104,32 +104,28 @@ MigrationState *migrate_get_current(void)
>      return &current_migration;
>  }
> 
> -/* For incoming */
> -static MigrationIncomingState *mis_current;
> -
>  MigrationIncomingState *migration_incoming_get_current(void)
>  {
> -    return mis_current;
> -}
> +    static bool once;
> +    static MigrationIncomingState mis_current;
> 
> -MigrationIncomingState *migration_incoming_state_new(QEMUFile* f)
> -{
> -    mis_current = g_new0(MigrationIncomingState, 1);
> -    mis_current->from_src_file = f;
> -    mis_current->state = MIGRATION_STATUS_NONE;
> -    QLIST_INIT(&mis_current->loadvm_handlers);
> -    qemu_mutex_init(&mis_current->rp_mutex);
> -    qemu_event_init(&mis_current->main_thread_load_event, false);
> -
> -    return mis_current;
> +    if (!once) {
> +        mis_current.state = MIGRATION_STATUS_NONE;
> +        memset(&mis_current, 0, sizeof(MigrationIncomingState));
> +        QLIST_INIT(&mis_current.loadvm_handlers);
> +        qemu_mutex_init(&mis_current.rp_mutex);
> +        qemu_event_init(&mis_current.main_thread_load_event, false);
> +        once = true;
> +    }
> +    return &mis_current;
>  }
> 
>  void migration_incoming_state_destroy(void)
>  {
> -    qemu_event_destroy(&mis_current->main_thread_load_event);
> -    loadvm_free_handlers(mis_current);
> -    g_free(mis_current);
> -    mis_current = NULL;
> +    struct MigrationIncomingState *mis = migration_incoming_get_current();
> +
> +    qemu_event_destroy(&mis->main_thread_load_event);
> +    loadvm_free_handlers(mis);
>  }
> 
> 
> @@ -375,11 +371,11 @@ static void process_incoming_migration_bh(void *opaque)
>  static void process_incoming_migration_co(void *opaque)
>  {
>      QEMUFile *f = opaque;
> -    MigrationIncomingState *mis;
> +    MigrationIncomingState *mis = migration_incoming_get_current();
>      PostcopyState ps;
>      int ret;
> 
> -    mis = migration_incoming_state_new(f);
> +    mis->from_src_file = f;
>      postcopy_state_set(POSTCOPY_INCOMING_NONE);
>      migrate_set_state(&mis->state, MIGRATION_STATUS_NONE,
>                        MIGRATION_STATUS_ACTIVE);
> diff --git a/migration/savevm.c b/migration/savevm.c
> index a831ec2..de84be5 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -2107,7 +2107,6 @@ void qmp_xen_load_devices_state(const char *filename, Error **errp)
>      }
>      f = qemu_fopen_channel_input(QIO_CHANNEL(ioc));
> 
> -    migration_incoming_state_new(f);

It's curious that this one is the odd case of not setting mis->from_src_file.

Anyway, I think it's OK but please test it with -incoming defer.

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>


>      ret = qemu_loadvm_state(f);
>      qemu_fclose(f);
>      if (ret < 0) {
> @@ -2123,6 +2122,7 @@ int load_vmstate(const char *name)
>      QEMUFile *f;
>      int ret;
>      AioContext *aio_context;
> +    MigrationIncomingState *mis = migration_incoming_get_current();
> 
>      if (!bdrv_all_can_snapshot(&bs)) {
>          error_report("Device '%s' is writable but does not support snapshots.",
> @@ -2173,7 +2173,7 @@ int load_vmstate(const char *name)
>      }
> 
>      qemu_system_reset(VMRESET_SILENT);
> -    migration_incoming_state_new(f);
> +    mis->from_src_file = f;
> 
>      aio_context_acquire(aio_context);
>      ret = qemu_loadvm_state(f);
> -- 
> 2.7.4
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK