Method DeleteFrame

tensorflow/core/common_runtime/propagator_state.cc:287–365

}

void PropagatorState::DeleteFrame(FrameState* frame, TaggedNodeSeq* ready) {
  // First, propagate dead_exits (if any) to the parent frame.
  FrameState* parent_frame = frame->parent_frame;
  IterationState* parent_iter_state = frame->parent_iter;
  if (parent_frame != nullptr) {
    mutex_lock parent_frame_lock(parent_frame->mu);
    // Propagate all the dead exits to the parent frame.
    mutex_lock this_frame_lock(frame->mu);

    for (const NodeItem* item : frame->dead_exits) {
      auto maybe_add_to_ready = [&](const NodeItem& dst_item, bool dst_ready,
                                    bool dst_dead) {
        if (dst_ready) {
          // NOTE(jiankeng.pt): RunGraphOp can not be dead in any time.
          if (dst_item.is_control_trigger || dst_item.is_run_graph_op) {
            dst_dead = false;
          }
          ready->emplace_back(&dst_item, parent_frame, parent_iter_state,
                              dst_dead);
          parent_iter_state->outstanding_ops++;
        }
      };

      auto propagate_to_non_merge = [&](PendingCounts::Handle dst_pending_id) {
        parent_iter_state->increment_dead_count(dst_pending_id);
        return parent_iter_state->decrement_pending(dst_pending_id, 1) == 0;
      };

      for (const EdgeInfo& e : item->output_edges()) {
        const NodeItem& dst_item =
            immutable_state_.graph_view().node_ref(e.dst_id);
        const auto dst_pending_id = immutable_state_.pending_ids()[e.dst_id];

        bool dst_dead = true;
        bool dst_ready;
        // We know this is a dead input to dst.
        if (dst_item.is_merge) {
          parent_iter_state->increment_dead_count(dst_pending_id);
          const int dead_cnt = parent_iter_state->dead_count(dst_pending_id);
          dst_dead = (dead_cnt == dst_item.num_inputs);
          dst_ready =
              (parent_iter_state->pending(dst_pending_id) == 1) && dst_dead;
        } else {
          dst_ready = propagate_to_non_merge(dst_pending_id);
        }
        maybe_add_to_ready(dst_item, dst_ready, dst_dead);
      }

      for (const ControlEdgeInfo& e : item->output_control_edges()) {
        const NodeItem& dst_item =
            immutable_state_.graph_view().node_ref(e.dst_id);
        const auto dst_pending_id = immutable_state_.pending_ids()[e.dst_id];

        bool dst_dead;
        bool dst_ready;
        // We know this is a dead input to dst.
        if (dst_item.is_merge) {
          parent_iter_state->decrement_pending(dst_pending_id, 2);