Update LoRA Weights via Tensor (#16226)

Co-authored-by: PopSoda2002 <zhouhp.me@gmail.com>

python/sglang/srt/entrypoints/engine.py

@@ -47,6 +47,7 @@ from sglang.srt.managers.io_struct import (
     GenerateReqInput,
     GetWeightsByNameReqInput,
     InitWeightsUpdateGroupReqInput,
+    LoadLoRAAdapterFromTensorsReqInput,
     LoadLoRAAdapterReqInput,
     MultimodalDataInputFormat,
     ReleaseMemoryOccupationReqInput,
@@ -600,6 +601,22 @@ class Engine(EngineBase):
             self.tokenizer_manager.get_weights_by_name(obj, None)
         )
 
+    def load_lora_adapter_from_tensors(
+        self, lora_name: str, tensors: List[Tuple[str, torch.Tensor]], config_dict: Dict
+    ):
+        # Load LoRA adapter again
+        serialized_tensors = MultiprocessingSerializer.serialize(
+            tensors, output_str=True
+        )
+        lora_req = LoadLoRAAdapterFromTensorsReqInput(
+            lora_name=lora_name,
+            config_dict=config_dict,
+            serialized_tensors=serialized_tensors,
+        )
+        return self.loop.run_until_complete(
+            self.tokenizer_manager.load_lora_adapter_from_tensors(lora_req, None)
+        )
+
     def load_lora_adapter(self, lora_name: str, lora_path: str, pinned: bool = False):
         """Load a new LoRA adapter without re-launching the engine."""
 

python/sglang/srt/entrypoints/http_server.py

@@ -103,6 +103,7 @@ from sglang.srt.managers.io_struct import (
     GetWeightsByNameReqInput,
     InitWeightsSendGroupForRemoteInstanceReqInput,
     InitWeightsUpdateGroupReqInput,
+    LoadLoRAAdapterFromTensorsReqInput,
     LoadLoRAAdapterReqInput,
     OpenSessionReqInput,
     ParseFunctionCallReq,
@@ -1062,6 +1063,21 @@ async def load_lora_adapter(obj: LoadLoRAAdapterReqInput, request: Request):
         )
 
 
+@app.api_route("/load_lora_adapter_from_tensors", methods=["POST"])
+async def load_lora_adapter_from_tensors(
+    obj: LoadLoRAAdapterFromTensorsReqInput, request: Request
+):
+    """Load a new LoRA adapter from tensors without re-launching the server."""
+    result = await _global_state.tokenizer_manager.load_lora_adapter_from_tensors(
+        obj, request
+    )
+
+    if result.success:
+        return ORJSONResponse(result, status_code=HTTPStatus.OK)
+    else:
+        return ORJSONResponse(result, status_code=HTTPStatus.BAD_REQUEST)
+
+
 @app.api_route("/unload_lora_adapter", methods=["POST"])
 async def unload_lora_adapter(obj: UnloadLoRAAdapterReqInput, request: Request):
     """Load a new LoRA adapter without re-launching the server."""