From a52f800e0ad5c50338377ce328cb902d8c5dbb43 Mon Sep 17 00:00:00 2001
From: "mergify[bot]" <37929162+mergify[bot]@users.noreply.github.com>
Date: Tue, 5 Nov 2024 12:01:58 +0000
Subject: [PATCH] [ros2_control_node] Add the realtime_tools lock_memory method
 to prevent page faults (backport #1822) (#1851)

---
 controller_manager/src/ros2_control_node.cpp | 7 +++++++
 doc/release_notes.rst                        | 1 +
 2 files changed, 8 insertions(+)

diff --git a/controller_manager/src/ros2_control_node.cpp b/controller_manager/src/ros2_control_node.cpp
index aa444cde69..263d0c48cb 100644
--- a/controller_manager/src/ros2_control_node.cpp
+++ b/controller_manager/src/ros2_control_node.cpp
@@ -44,6 +44,13 @@ int main(int argc, char ** argv)
 
   auto cm = std::make_shared<controller_manager::ControllerManager>(executor, manager_node_name);
 
+  const bool lock_memory = cm->get_parameter_or<bool>("lock_memory", true);
+  std::string message;
+  if (lock_memory && !realtime_tools::lock_memory(message))
+  {
+    RCLCPP_WARN(cm->get_logger(), "Unable to lock the memory : '%s'", message.c_str());
+  }
+
   RCLCPP_INFO(cm->get_logger(), "update rate is %d Hz", cm->get_update_rate());
   const int thread_priority = cm->get_parameter_or<int>("thread_priority", kSchedPriority);
   RCLCPP_INFO(
diff --git a/doc/release_notes.rst b/doc/release_notes.rst
index b9ad7a195f..9dbc08436b 100644
--- a/doc/release_notes.rst
+++ b/doc/release_notes.rst
@@ -19,3 +19,4 @@ controller_manager
 
 * The ``ros2_control_node`` node now accepts the ``thread_priority`` parameter to set the scheduler priority of the controller_manager's RT thread (`#1820 <https://github.com/ros-controls/ros2_control/pull/1820>`_).
 * Added support for the wildcard entries for the controller configuration files (`#1724 <https://github.com/ros-controls/ros2_control/pull/1724>`_).
+* The ``ros2_control_node`` node has a new ``lock_memory`` parameter to lock memory at startup to physical RAM in order to avoid page faults (`#1822 <https://github.com/ros-controls/ros2_control/pull/1822>`_).