Re: [Qemu-devel] [PATCH] migration: avoid starting a new migration task while the previous one still exist

[Paolo Bonzini <bonzini@gnu.org>]

Il 04/11/2013 12:26, Zhanghaoyu (A) ha scritto:
> Avoid starting a new migration task while the previous one still exist.

Can you explain how to reproduce the problem?

Also please use pbonzini@redhat.com instead.  My Gmail address is an
implementation detail. :)

> Signed-off-by: Zeng Junliang <zengjunliang@huawei.com>

It looks like the author of the patch is not the same as you.  If so,
you need to make Zeng Junliang the author (using --author on the "git
commit" command line) and add your own signoff line.

Paolo

> ---
>  migration.c |   34 ++++++++++++++++++++++------------
>  1 files changed, 22 insertions(+), 12 deletions(-)
> 
> diff --git a/migration.c b/migration.c
> index 2b1ab20..ab4c439 100644
> --- a/migration.c
> +++ b/migration.c
> @@ -40,8 +40,10 @@ enum {
>      MIG_STATE_ERROR = -1,
>      MIG_STATE_NONE,
>      MIG_STATE_SETUP,
> +    MIG_STATE_CANCELLING,
>      MIG_STATE_CANCELLED,
>      MIG_STATE_ACTIVE,
> +    MIG_STATE_COMPLETING,
>      MIG_STATE_COMPLETED,
>  };
>  
> @@ -196,6 +198,8 @@ MigrationInfo *qmp_query_migrate(Error **errp)
>          info->has_total_time = false;
>          break;
>      case MIG_STATE_ACTIVE:
> +    case MIG_STATE_CANCELLING:
> +    case MIG_STATE_COMPLETING:
>          info->has_status = true;
>          info->status = g_strdup("active");
>          info->has_total_time = true;
> @@ -282,6 +286,13 @@ void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
>  
>  /* shared migration helpers */
>  
> +static void migrate_set_state(MigrationState *s, int old_state, int new_state)
> +{
> +    if (atomic_cmpxchg(&s->state, old_state, new_state) == new_state) {
> +        trace_migrate_set_state(new_state);
> +    }
> +}
> +
>  static void migrate_fd_cleanup(void *opaque)
>  {
>      MigrationState *s = opaque;
> @@ -301,20 +312,18 @@ static void migrate_fd_cleanup(void *opaque)
>  
>      assert(s->state != MIG_STATE_ACTIVE);
>  
> -    if (s->state != MIG_STATE_COMPLETED) {
> +    if (s->state != MIG_STATE_COMPLETING) {
>          qemu_savevm_state_cancel();
> +        if (s->state == MIG_STATE_CANCELLING) {
> +            migrate_set_state(s, MIG_STATE_CANCELLING, MIG_STATE_CANCELLED); 
> +        }
> +    }else {
> +        migrate_set_state(s, MIG_STATE_COMPLETING, MIG_STATE_COMPLETED); 
>      }
>  
>      notifier_list_notify(&migration_state_notifiers, s);
>  }
>  
> -static void migrate_set_state(MigrationState *s, int old_state, int new_state)
> -{
> -    if (atomic_cmpxchg(&s->state, old_state, new_state) == new_state) {
> -        trace_migrate_set_state(new_state);
> -    }
> -}
> -
>  void migrate_fd_error(MigrationState *s)
>  {
>      DPRINTF("setting error state\n");
> @@ -328,7 +337,7 @@ static void migrate_fd_cancel(MigrationState *s)
>  {
>      DPRINTF("cancelling migration\n");
>  
> -    migrate_set_state(s, s->state, MIG_STATE_CANCELLED);
> +    migrate_set_state(s, s->state, MIG_STATE_CANCELLING);
>  }
>  
>  void add_migration_state_change_notifier(Notifier *notify)
> @@ -405,7 +414,8 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
>      params.blk = has_blk && blk;
>      params.shared = has_inc && inc;
>  
> -    if (s->state == MIG_STATE_ACTIVE || s->state == MIG_STATE_SETUP) {
> +    if (s->state == MIG_STATE_ACTIVE || s->state == MIG_STATE_SETUP ||
> +        s->state == MIG_STATE_COMPLETING || s->state == MIG_STATE_CANCELLING) {
>          error_set(errp, QERR_MIGRATION_ACTIVE);
>          return;
>      }
> @@ -594,7 +604,7 @@ static void *migration_thread(void *opaque)
>                  }
>  
>                  if (!qemu_file_get_error(s->file)) {
> -                    migrate_set_state(s, MIG_STATE_ACTIVE, MIG_STATE_COMPLETED);
> +                    migrate_set_state(s, MIG_STATE_ACTIVE, MIG_STATE_COMPLETING);
>                      break;
>                  }
>              }
> @@ -634,7 +644,7 @@ static void *migration_thread(void *opaque)
>      }
>  
>      qemu_mutex_lock_iothread();
> -    if (s->state == MIG_STATE_COMPLETED) {
> +    if (s->state == MIG_STATE_COMPLETING) {
>          int64_t end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
>          s->total_time = end_time - s->total_time;
>          s->downtime = end_time - start_time;
>