chore: import upstream snapshot with attribution

python/ray/_private/gc_collect_manager.py

@@ -0,0 +1,51 @@
+import gc
+import logging
+import threading
+import time
+from typing import Callable, Optional
+
+logger = logging.getLogger(__name__)
+
+
+class PythonGCThread(threading.Thread):
+    """A background thread that triggers Python garbage collection.
+
+    This thread waits for GC events from CoreWorker and triggers `gc.collect()` when
+    when requested."""
+
+    def __init__(self, *, gc_collect_func: Optional[Callable] = None):
+        logger.debug("Starting Python GC thread")
+        super().__init__(name="PythonGCThread", daemon=True)
+        self._should_exit = False
+        self._gc_event = threading.Event()
+        # Sets the gc_collect_func (only for testing), defaults to gc.collect
+        self._gc_collect_func = gc_collect_func or gc.collect
+
+    def trigger_gc(self) -> None:
+        self._gc_event.set()
+
+    def run(self):
+        while not self._should_exit:
+            self._gc_event.wait()
+            self._gc_event.clear()
+
+            if self._should_exit:
+                break
+
+            try:
+                start = time.monotonic()
+                num_freed = self._gc_collect_func()
+                if num_freed > 0:
+                    logger.debug(
+                        "gc.collect() freed {} refs in {} seconds".format(
+                            num_freed, time.monotonic() - start
+                        )
+                    )
+            except Exception as e:
+                logger.error(f"Error during GC: {e}")
+
+    def stop(self):
+        logger.debug("Stopping Python GC thread")
+        self._should_exit = True
+        self._gc_event.set()
+        self.join()