[Feat] UCM supports recovery form load failure

ucm/integration/vllm/ucm_connector.py

@@ -184,6 +184,9 @@ def __init__(self, vllm_config: "VllmConfig", role: KVConnectorRole):
                 else torch.npu.synchronize
             )
 
+        # invlalid block ids due to load errors
+        self._invalid_block_ids: set[int] = set()
+
     def generate_hash(self, block_size: int, request: "Request") -> list[str]:
         token_ids = request.all_token_ids
 
@@ -513,6 +516,9 @@ def start_load_kv(self, forward_context: "ForwardContext", **kwargs) -> None:
             # TODO error handling
             if self.global_rank == 0 or not self.load_only_first_rank:
                 if self.store.wait(task) != 0:
+                    self._invalid_block_ids.update(
+                        metadata.request_meta[request_id].load_block_ids[1]
+                    )
                     logger.error(f"request {request_id} load kv cache failed.")
             if self.load_only_first_rank:
                 self._broadcast(req_broadcast_addr[request_id])
@@ -626,6 +632,18 @@ def wait_for_save(self) -> None:
     def clear_connector_metadata(self) -> None:
         super().clear_connector_metadata()
 
+    def get_block_ids_with_load_errors(self) -> set[int]:
+        """
+        Get the set of block IDs that failed to load.
+
+        Returns:
+            Set of block IDs that encountered load errors.
+            Empty set if no load errors occurred.
+        """
+        res = self._invalid_block_ids
+        self._invalid_block_ids = set()
+        return res
+
 
 class UCMLayerWiseConnector(UCMDirectConnector):
     """
@@ -866,3 +884,13 @@ def clear_connector_metadata(self) -> None:
         after the model execution.
         """
         self.connector.clear_connector_metadata()
+
+    def get_block_ids_with_load_errors(self) -> set[int]:
+        """
+        Get the set of block IDs that failed to load.
+
+        Returns:
+            Set of block IDs that encountered load errors.
+            Empty set if no load errors occurred.
+        """
+        return self.connector.get_block_ids_with_load_errors()