From 60406cb9825869714a68d191da55e91def0afb9b Mon Sep 17 00:00:00 2001
From: firestar5683 <168790843+firestar5683@users.noreply.github.com>
Date: Thu, 2 Jul 2026 10:44:59 -0500
Subject: [PATCH] Memory Hither

---
 system/manager/process_config.py    | 14 +++++++++-----
 system/manager/test/test_manager.py | 27 ++++++++++++++++++++++-----
 2 files changed, 31 insertions(+), 10 deletions(-)

diff --git a/system/manager/process_config.py b/system/manager/process_config.py
index cfce04dc6..d5b33cd90 100644
--- a/system/manager/process_config.py
+++ b/system/manager/process_config.py
@@ -33,14 +33,12 @@ def python_ui_enabled(device_type: str) -> bool:
   return device_type not in ("tici", "tizi")
 
 
-def python_process_start_method(uses_python_ui: bool, is_pc: bool = PC) -> str:
-  # Native/QT UI devices rely on fork copy-on-write to keep onroad memory low.
-  # Python/raylib UI uses subprocess to avoid fork/import-lock boot hangs.
+def python_ui_process_start_method(uses_python_ui: bool, is_pc: bool = PC) -> str:
   return "fork" if is_pc or not uses_python_ui else "subprocess"
 
 
 PYTHON_UI = python_ui_enabled(device_type)
-os.environ.setdefault("PYTHON_PROCESS_START_METHOD", python_process_start_method(PYTHON_UI))
+PYTHON_UI_PROCESS_START_METHOD = python_ui_process_start_method(PYTHON_UI)
 
 from openpilot.system.manager.process import PythonProcess, NativeProcess, DaemonProcess
 
@@ -176,7 +174,13 @@ procs += [
 ]
 
 if PYTHON_UI:
-  procs.append(PythonProcess("ui", "selfdrive.ui.ui", always_run, watchdog_max_dt=UI_WATCHDOG_MAX_DT))
+  procs.append(PythonProcess(
+    "ui",
+    "selfdrive.ui.ui",
+    always_run,
+    watchdog_max_dt=UI_WATCHDOG_MAX_DT,
+    start_method=PYTHON_UI_PROCESS_START_METHOD,
+  ))
 else:
   procs.append(NativeProcess("ui", "selfdrive/ui", ["./ui"], always_run, watchdog_max_dt=UI_WATCHDOG_MAX_DT))
 
diff --git a/system/manager/test/test_manager.py b/system/manager/test/test_manager.py
index 375bc4611..d4fde7810 100644
--- a/system/manager/test/test_manager.py
+++ b/system/manager/test/test_manager.py
@@ -9,7 +9,13 @@ from cereal import car
 from openpilot.common.params import Params, ParamKeyFlag
 import openpilot.system.manager.manager as manager
 from openpilot.system.manager.process import ensure_running
-from openpilot.system.manager.process_config import managed_processes, procs, python_process_start_method, python_ui_enabled
+from openpilot.system.manager.process import PythonProcess
+from openpilot.system.manager.process_config import (
+  managed_processes,
+  procs,
+  python_ui_enabled,
+  python_ui_process_start_method,
+)
 from openpilot.system.hardware import HARDWARE
 
 os.environ['FAKEUPLOAD'] = "1"
@@ -111,10 +117,21 @@ class TestManager:
     assert names.index("the_galaxy") < ui_idx
     assert names.index("galaxy") < ui_idx
 
-  def test_python_process_start_method_follows_ui_implementation(self):
-    assert python_process_start_method(False, False) == "fork"
-    assert python_process_start_method(True, False) == "subprocess"
-    assert python_process_start_method(True, True) == "fork"
+  def test_python_ui_process_start_method_follows_ui_implementation(self):
+    assert python_ui_process_start_method(False, False) == "fork"
+    assert python_ui_process_start_method(True, False) == "subprocess"
+    assert python_ui_process_start_method(True, True) == "fork"
+
+  def test_python_ui_subprocess_is_scoped_to_ui(self):
+    ui_proc = managed_processes["ui"]
+    uses_python_ui = python_ui_enabled(HARDWARE.get_device_type())
+
+    assert isinstance(ui_proc, PythonProcess) == uses_python_ui
+    if uses_python_ui:
+      assert ui_proc.start_method == python_ui_process_start_method(uses_python_ui)
+    for proc in procs:
+      if isinstance(proc, PythonProcess) and proc.name != "ui":
+        assert proc.start_method is None
 
   def test_python_ui_env_override(self, monkeypatch):
     monkeypatch.setenv("USE_RAYLIB_UI", "1")