[Perf] Move gc.freeze logic from EngineCoreProc to EngineCore for better coverage (#27896)

Signed-off-by: Jialin Ouyang <Jialin.Ouyang@gmail.com>

vllm/entrypoints/openai/api_server.py

@@ -1,8 +1,6 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
-
 import asyncio
-import gc
 import hashlib
 import importlib
 import inspect
@@ -118,6 +116,7 @@ from vllm.reasoning import ReasoningParserManager
 from vllm.tasks import POOLING_TASKS
 from vllm.usage.usage_lib import UsageContext
 from vllm.utils.argparse_utils import FlexibleArgumentParser
+from vllm.utils.gc_utils import freeze_gc_heap
 from vllm.utils.network_utils import is_valid_ipv6_address
 from vllm.utils.system_utils import decorate_logs, set_ulimit
 from vllm.v1.engine.exceptions import EngineDeadError
@@ -153,8 +152,7 @@ async def lifespan(app: FastAPI):
 
         # Mark the startup heap as static so that it's ignored by GC.
         # Reduces pause times of oldest generation collections.
-        gc.collect()
-        gc.freeze()
+        freeze_gc_heap()
         try:
             yield
         finally: