[14/41] migration: cleanup migration (including thread) in the iothread

Perform final cleanup in a bottom half, and add joining the thread to
the series of cleanup actions.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 include/migration/migration.h |    1 +
 migration.c                   |   37 +++++++++++++++++++------------------
 2 files changed, 20 insertions(+), 18 deletions(-)

On 02/15/2013 07:46 PM, Paolo Bonzini wrote:
> Perform final cleanup in a bottom half, and add joining the thread to
> the series of cleanup actions.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  include/migration/migration.h |    1 +
>  migration.c                   |   37 +++++++++++++++++++------------------
>  2 files changed, 20 insertions(+), 18 deletions(-)
> 
> diff --git a/include/migration/migration.h b/include/migration/migration.h
> index 4928642..d78bbbb 100644
> --- a/include/migration/migration.h
> +++ b/include/migration/migration.h
> @@ -38,6 +38,7 @@ struct MigrationState
>      size_t buffer_size;
>      size_t buffer_capacity;
>      QemuThread thread;
> +    QEMUBH *cleanup_bh;
>  
>      QEMUFile *file;
>      int fd;
> diff --git a/migration.c b/migration.c
> index a7f619b..8abaaea 100644
> --- a/migration.c
> +++ b/migration.c
> @@ -260,8 +260,13 @@ void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
>  
>  /* shared migration helpers */
>  
> -static void migrate_fd_cleanup(MigrationState *s)
> +static void migrate_fd_cleanup(void *opaque)
>  {
> +    MigrationState *s = opaque;
> +
> +    qemu_bh_delete(s->cleanup_bh);
> +    s->cleanup_bh = NULL;
> +
>      if (s->file) {
>          DPRINTF("closing file\n");
>          qemu_fclose(s->file);
> @@ -281,15 +286,9 @@ static void migrate_fd_cleanup(MigrationState *s)
>  void migrate_fd_error(MigrationState *s)
>  {
>      DPRINTF("setting error state\n");
> -    __sync_val_compare_and_swap(&s->state, MIG_STATE_ACTIVE, MIG_STATE_ERROR);
> -    migrate_fd_cleanup(s);
> -}
> -
> -static void migrate_fd_completed(MigrationState *s)
> -{
> -    DPRINTF("setting completed state\n");
> -    __sync_val_compare_and_swap(&s->state, MIG_STATE_ACTIVE, MIG_STATE_COMPLETED);
> -    migrate_fd_cleanup(s);
> +    assert(s->file == NULL);
> +    s->state = MIG_STATE_ERROR;
> +    notifier_list_notify(&migration_state_notifiers, s);
>  }
>  
>  static ssize_t migrate_fd_put_buffer(MigrationState *s, const void *data,
> @@ -316,7 +315,6 @@ static void migrate_fd_cancel(MigrationState *s)
>      DPRINTF("cancelling migration\n");
>  
>      __sync_val_compare_and_swap(&s->state, MIG_STATE_ACTIVE, MIG_STATE_CANCELLED);
> -    migrate_fd_cleanup(s);
>  }
>  
>  int migrate_fd_close(MigrationState *s)
> @@ -580,6 +578,11 @@ static int buffered_close(void *opaque)
>  
>      DPRINTF("closing\n");
>  
> +    qemu_mutex_unlock_iothread();
> +    qemu_thread_join(&s->thread);
> +    qemu_mutex_lock_iothread();
> +    assert (s->state != MIG_STATE_ACTIVE);
> +
>      return migrate_fd_close(s);
>  }
>  
> @@ -692,13 +695,9 @@ static void *buffered_file_thread(void *opaque)
>          }
>          buffered_flush(s);
>          if (qemu_file_get_error(s->file)) {
> -            qemu_mutex_lock_iothread();
> -            migrate_fd_error(s);
> -            qemu_mutex_unlock_iothread();
> +            __sync_val_compare_and_swap(&s->state, MIG_STATE_ACTIVE, MIG_STATE_ERROR);
>          } else if (last_round && s->buffer_size == 0) {
> -            qemu_mutex_lock_iothread();
> -            migrate_fd_completed(s);
> -            qemu_mutex_unlock_iothread();
> +            __sync_val_compare_and_swap(&s->state, MIG_STATE_ACTIVE, MIG_STATE_COMPLETED);
>          }
>      }
>  
> @@ -714,6 +713,7 @@ static void *buffered_file_thread(void *opaque)
>              vm_start();
>          }
>      }
> +    qemu_bh_schedule(s->cleanup_bh);
>      qemu_mutex_unlock_iothread();
>  
>      g_free(s->buffer);
> @@ -739,9 +739,10 @@ void migrate_fd_connect(MigrationState *s)
>  
>      s->xfer_limit = s->bandwidth_limit / XFER_LIMIT_RATIO;
>  
> +    s->cleanup_bh = qemu_bh_new(migrate_fd_cleanup, s);
>      s->file = qemu_fopen_ops(s, &buffered_file_ops);
>  
>      qemu_thread_create(&s->thread, buffered_file_thread, s,
> -                       QEMU_THREAD_DETACHED);
> +                       QEMU_THREAD_JOINABLE);
>      notifier_list_notify(&migration_state_notifiers, s);
>  }
> 

Reviewed-by: Orit Wasserman <owasserm@redhat.com>

Paolo Bonzini <pbonzini@redhat.com> wrote:
> Perform final cleanup in a bottom half, and add joining the thread to
> the series of cleanup actions.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  include/migration/migration.h |    1 +
>  migration.c                   |   37 +++++++++++++++++++------------------
>  2 files changed, 20 insertions(+), 18 deletions(-)
>

Reviewed-by: Juan Quintela <quintela@redhat.com>

Previously, I have had trouble with bottom half here because they added
a lot of latency between we made it runnable until they decided to run.
This was the reason that I didn't used them on my previous tries.

But I haven't hit the problem with this series.