From f864abe29da9a4a9dbe2df85a18c254f400ed1a9 Mon Sep 17 00:00:00 2001
From: Oleg Vivtash <oleg@vivtash.net>
Date: Wed, 8 Apr 2015 20:18:19 +0300
Subject: [PATCH] Disable Linux THP on Debian distros

---
 README.md            |  1 +
 defaults/main.yml    |  1 +
 files/disable_thp.sh | 11 +++++++++++
 tasks/configure.yml  | 12 ++++++++++++
 4 files changed, 25 insertions(+)
 create mode 100644 files/disable_thp.sh

diff --git a/README.md b/README.md
index e2cfdd7..a8d0c46 100644
--- a/README.md
+++ b/README.md
@@ -14,6 +14,7 @@ mongodb_package: mongodb-org
 
 mongodb_force_wait_for_port: false                # When not forced, the role will wait for mongod port to become available only with systemd
 mongodb_pymongo_from_pip: false                   # Install latest PyMongo via PIP or package manager
+mongodb_disable_thp: true
 
 mongodb_user: mongodb
 mongodb_daemon_name: "{{ 'mongod' if ('mongodb-org' in mongodb_package) else 'mongodb' }}"
diff --git a/defaults/main.yml b/defaults/main.yml
index 68b4a37..0e95959 100644
--- a/defaults/main.yml
+++ b/defaults/main.yml
@@ -3,6 +3,7 @@
 mongodb_package: mongodb-org
 mongodb_force_wait_for_port: false
 mongodb_pymongo_from_pip: false                   # Install latest PyMongo via PIP or package manager
+mongodb_disable_thp: true
 
 mongodb_user: mongodb
 mongodb_daemon_name: "{{ 'mongod' if ('mongodb-org' in mongodb_package) else 'mongodb' }}"
diff --git a/files/disable_thp.sh b/files/disable_thp.sh
new file mode 100644
index 0000000..abf2f48
--- /dev/null
+++ b/files/disable_thp.sh
@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+
+if test -f /sys/kernel/mm/transparent_hugepage/khugepaged/defrag; then
+  echo 0 > /sys/kernel/mm/transparent_hugepage/khugepaged/defrag
+fi
+if test -f /sys/kernel/mm/transparent_hugepage/defrag; then
+  echo never > /sys/kernel/mm/transparent_hugepage/defrag
+fi
+if test -f /sys/kernel/mm/transparent_hugepage/enabled; then
+  echo never > /sys/kernel/mm/transparent_hugepage/enabled
+fi
\ No newline at end of file
diff --git a/tasks/configure.yml b/tasks/configure.yml
index d60ea4f..971f40c 100644
--- a/tasks/configure.yml
+++ b/tasks/configure.yml
@@ -50,6 +50,18 @@
   template: src=mongod.conf.j2 dest=/etc/mongod.conf backup=yes owner=root group=root mode=0644
   register: config_result
 
+- name: Install disable_thp script
+  copy: src=disable_thp.sh dest=/usr/local/bin/disable_thp.sh mode='u=rwx,g=rx,o=rx'
+  when: ansible_os_family == 'Debian' and mongodb_disable_thp
+
+- name: Disable Linux transparent hugepages now
+  command: /usr/local/bin/disable_thp.sh
+  when: ansible_os_family == 'Debian' and mongodb_disable_thp
+
+- name: Disable Linux transparent hugepages on boot
+  lineinfile: dest=/etc/rc.local regexp='/usr/local/bin/disable_thp.sh' line='if test -f '/usr/local/bin/disable_thp.sh'; /usr/local/bin/disable_thp.sh; fi'
+  when: ansible_os_family == 'Debian' and mongodb_disable_thp
+
 - name: mongodb restart
   service: name={{ mongodb_daemon_name }} state=restarted
   when: config_result|changed