[BugFix]Reclaim resources to prevent memory leaks when use LMCacheMPConnector (#30745)

Signed-off-by: wz1qqx <ziqi.wang@novita.ai>
Co-authored-by: wz1qqx <ziqi.wang@novita.ai>

vllm/distributed/kv_transfer/kv_connector/v1/lmcache_integration/multi_process_adapter.py

@@ -147,6 +147,14 @@ class LMCacheMPSchedulerAdapter:
         """
         return self.blocks_in_chunk
 
+    def _cleanup_lookup_result(self, request_id: str) -> None:
+        """
+        Clean up lookup future for a finished request to prevent memory leak.
+        Args:
+            request_id: The ID of the finished request.
+        """
+        self.lookup_futures.pop(request_id, None)
+
     # Helper functions
     def _create_key(self, block_hash: bytes) -> IPCCacheEngineKey:
         """Convert a block hash to an IPC cache engine key"""

vllm/distributed/kv_transfer/kv_connector/v1/lmcache_mp_connector.py

@@ -701,6 +701,8 @@ class LMCacheMPConnector(KVConnectorBase_V1):
                 if condition
                 else LMCacheMPRequestState.READY
             )
+            # Clean up lookup future in scheduler adapter
+            self.scheduler_adapter._cleanup_lookup_result(request.request_id)
 
     def build_connector_meta(
         self, scheduler_output: SchedulerOutput
@@ -754,6 +756,8 @@ class LMCacheMPConnector(KVConnectorBase_V1):
             Optional KVTransferParams to be included in the request outputs
             returned by the engine.
         """
+        # Clean up request tracker to prevent memory leak
+        self._cleanup_request_tracker(request.request_id)
         return True, None
 
     def take_events(self) -> Iterable["KVCacheEvent"]:
@@ -915,3 +919,15 @@ class LMCacheMPConnector(KVConnectorBase_V1):
             new_tracker = LMCacheMPRequestTracker(request)
             self.request_trackers[request_id] = new_tracker
         return self.request_trackers[request_id]
+
+    def _cleanup_request_tracker(self, request_id: str) -> None:
+        """
+        Clean up request tracker and associated lookup future for a request.
+        This should be called when a request is finished to prevent memory leak.
+        """
+        # Clean up request tracker
+        if self.request_trackers.pop(request_id, None):
+            logger.debug(
+                "[KVConnector] Cleaned up request_tracker for request %s",
+                request_id,
+            )