695: New method for managing THP

roles/mongodb_linux/defaults/main.yml

@@ -12,3 +12,5 @@ memlock_limit: 1024
 mongodb_ntp_package:
 mongodb_ntp_service:
 mongodb_gnu_c_lib:
+
+mongodb_enable_thp: false

roles/mongodb_linux/files/thp-enable.service

@@ -0,0 +1,10 @@
+[Unit]
+Description=Enable Transparent Huge Pages
+ConditionPathIsDirectory=/sys/kernel/mm/transparent_hugepage
+
+[Service]
+Type=oneshot
+ExecStart=/usr/bin/env sh -c "echo 'always' > /sys/kernel/mm/transparent_hugepage/enabled && echo 'always' > /sys/kernel/mm/transparent_hugepage/defrag"
+
+[Install]
+WantedBy=multi-user.target

roles/mongodb_linux/molecule/default/tests/test_default.py

@@ -42,7 +42,7 @@ def test_swappiness_value(host):
 
 
 def test_thp_service_file(host):
-    f = host.file("/etc/systemd/system/disable-transparent-huge-pages.service")
+    f = host.file("/etc/systemd/system/manage-transparent-huge-pages.service")
 
     assert f.exists
     assert f.user == "root"

roles/mongodb_linux/tasks/main.yml

@@ -140,10 +140,10 @@
     - "setup"
 
 # https://docs.mongodb.com/manual/tutorial/transparent-huge-pages/
-- name: Ensure thp-disable service exists
+- name: Ensure manage-transparent-huge-pages service exists
   copy:
-    src: thp-disable.service
-    dest: /etc/systemd/system/disable-transparent-huge-pages.service
+    src: "{{ mongodb_enable_thp | ternary('thp-enable.service', 'thp-disable.service') }}"
+    dest: /etc/systemd/system/manage-transparent-huge-pages.service
     owner: root
     group: root
   register: thp
@@ -165,28 +165,12 @@
     path: /sys/kernel/mm/transparent_hugepage
   register: sys_thp
 
-- name: Check if disable-transparent-huge-pages service is already run
-  shell: cat /sys/kernel/mm/transparent_hugepage/enabled | grep -o '{{ bs }}[never{{ bs }}]'
-  when: sys_thp.stat.exists
-  register: _huge_page_status
-  ignore_errors: yes
-  changed_when: _huge_page_status.stdout == ""
-  tags:
-    - "linux"
-    - "service"
-    - "setup"
-  vars:
-    bs: \
-
-- debug:
-    var:  _huge_page_status.stdout
-
-- name: Enable disable-transparent-huge-pages service
+- name: Enable manage-transparent-huge-pages service
   service:
-    name: disable-transparent-huge-pages
+    name: manage-transparent-huge-pages
     state: started
     enabled: yes
-  when: (sys_thp.stat.exists) and (_huge_page_status.stdout == "")
+  when: thp.changed
   tags:
     - "linux"
     - "service"