[Core] Make sleep-mode backend capability flags communicator-agnostic (#47243)

tests/v1/worker/test_sleep_mode_backend.py

@@ -23,13 +23,13 @@ def test_cumem_is_the_default_registered_backend():
 
 
 def test_cumem_capability_flags():
-    # cumem leaves NCCL untouched but does not preserve compiled artifacts,
-    # graphs, or durable state - these flags are what the executor and /health
-    # introspect to decide reinit / persistence behavior.
+    # cumem leaves communicators untouched but does not preserve compiled
+    # artifacts, graphs, or durable state - these flags are what the executor and
+    # /health introspect to decide reinit / persistence behavior.
     assert CuMemBackend.is_supported() is True
-    assert CuMemBackend.preserves_nccl() is True
+    assert CuMemBackend.preserves_communicators() is True
     assert CuMemBackend.preserves_compiled_artifacts() is False
-    assert CuMemBackend.preserves_graphs_with_nccl() is False
+    assert CuMemBackend.preserves_graphs_with_communicators() is False
     assert CuMemBackend.supports_durable_storage() is False
 
 

vllm/device_allocator/sleep_mode_backend.py

@@ -81,9 +81,9 @@ class SleepModeBackend(ABC):
         return True
 
     @classmethod
-    def preserves_nccl(cls) -> bool:
-        """If False, NCCL communicators are destroyed by ``suspend`` and the
-        executor must re-initialize them on ``resume``."""
+    def preserves_communicators(cls) -> bool:
+        """If False, collective communicators (e.g. NCCL) are destroyed by
+        ``suspend`` and the executor must re-initialize them on ``resume``."""
         return False
 
     @classmethod
@@ -93,9 +93,10 @@ class SleepModeBackend(ABC):
         return False
 
     @classmethod
-    def preserves_graphs_with_nccl(cls) -> bool:
-        """If True, CUDA graphs containing NCCL collectives stay valid after
-        resume. False when NCCL is rebuilt (embedded comm handles go stale)."""
+    def preserves_graphs_with_communicators(cls) -> bool:
+        """If True, CUDA graphs containing collective communicators (e.g. NCCL)
+        stay valid after resume. False when communicators are rebuilt (embedded
+        comm handles go stale)."""
         return False
 
     @classmethod
@@ -132,9 +133,9 @@ class CuMemBackend(SleepModeBackend):
         self._state = "RUNNING"
 
     @classmethod
-    def preserves_nccl(cls) -> bool:
-        # NCCL buffers live outside CuMemAllocator's pool, so an allocator-level
-        # sleep leaves the communicators intact (no reinit needed on resume).
+    def preserves_communicators(cls) -> bool:
+        # Communicator buffers (e.g. NCCL) live outside CuMemAllocator's pool, so
+        # an allocator-level sleep leaves them intact (no reinit needed on resume).
         return True