garbage_collection: freeze objects on klippy ready (#6794)

This significantly reduces the amount of data in the generation 2 garbage collection bucket from the initial startup of klipper.

Signed-off-by: Branden Cash <203336+ammmze@users.noreply.github.com>

klippy/extras/garbage_collection.py

@@ -0,0 +1,31 @@
+# Garbage collection optimizations
+#
+# Copyright (C) 2025  Branden Cash <ammmze@gmail.com>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+import gc
+import logging
+
+class GarbageCollection:
+    def __init__(self, config):
+        self.printer = config.get_printer()
+        # feature check ... freeze/unfreeze is only available in python 3.7+
+        can_freeze = hasattr(gc, 'freeze') and hasattr(gc, 'unfreeze')
+        if can_freeze:
+            self.printer.register_event_handler("klippy:ready",
+                                                self._handle_ready)
+            self.printer.register_event_handler("klippy:disconnect",
+                                                self._handle_disconnect)
+
+    def _handle_ready(self):
+        logging.debug("Running full garbage collection and freezing")
+        for n in range(3):
+            gc.collect(n)
+        gc.freeze()
+
+    def _handle_disconnect(self):
+        logging.debug("Unfreezing garbage collection")
+        gc.unfreeze()
+
+def load_config(config):
+    return GarbageCollection(config)

klippy/toolhead.py

@@ -290,7 +290,7 @@ class ToolHead:
                                             self._handle_shutdown)
         # Load some default modules
         modules = ["gcode_move", "homing", "idle_timeout", "statistics",
-                   "manual_probe", "tuning_tower"]
+                   "manual_probe", "tuning_tower", "garbage_collection"]
         for module_name in modules:
             self.printer.load_object(config, module_name)
     # Print time and flush tracking