[Refactor][Diffusion] Read the resolved offload policy outside the config layer (#7327)

Signed-off-by: specture724 <specture724@gmail.com>
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
Co-authored-by: Hongsheng Liu <liuhongsheng4@huawei.com>

vllm_omni/diffusion/diffusion_engine.py

@@ -44,7 +44,11 @@ from vllm_omni.diffusion.io_support import (
     supports_audio_output,
     supports_multimodal_input,
 )
-from vllm_omni.diffusion.offloader.config import any_selected_component_uses_allgather
+from vllm_omni.diffusion.offloader.config import (
+    OffloadStrategy,
+    any_selected_component_uses_allgather,
+    resolve_offload_strategy,
+)
 from vllm_omni.diffusion.output_formatter import (
     format_diffusion_outputs,
     format_empty_diffusion_outputs,
@@ -573,7 +577,8 @@ class DiffusionEngine:
         if output.media is not None:
             if output.output is not None:
                 raise ValueError("DiffusionOutput cannot contain both media and legacy output")
-            media = output.media.to_cpu() if self.od_config.enable_cpu_offload else output.media
+            model_level = resolve_offload_strategy(self.od_config) is OffloadStrategy.MODEL_LEVEL
+            media = output.media.to_cpu() if model_level else output.media
             output_data = media.video.tensor
             outputs = finalize_diffusion_media(media, sampling_params=request.sampling_params)
         else:
@@ -585,7 +590,7 @@ class DiffusionEngine:
             # post-processing to avoid device OOM — model weights may still
             # reside on the device and leave no headroom for intermediates.
             output_data = output.output
-            if self.od_config.enable_cpu_offload:
+            if resolve_offload_strategy(self.od_config) is OffloadStrategy.MODEL_LEVEL:
                 output_data = _move_tensor_tree_to_cpu(output_data)
 
             if self.post_process_func is not None: