From 554c086b798755eeaec213cf4db05af178d39fa3 Mon Sep 17 00:00:00 2001
From: Jeremy Lecour <jlecour@evolix.fr>
Date: Thu, 20 Oct 2022 14:38:12 +0200
Subject: [PATCH] redis: variable to disable transparent hugepage (default: do
 nothing)

---
 CHANGELOG.md            |  1 +
 redis/defaults/main.yml |  4 ++++
 redis/handlers/main.yml |  5 +++++
 redis/tasks/main.yml    | 24 ++++++++++++++----------
 redis/tasks/thp.yml     | 34 ++++++++++++++++++++++++++++++++++
 5 files changed, 58 insertions(+), 10 deletions(-)
 create mode 100644 redis/tasks/thp.yml

diff --git a/CHANGELOG.md b/CHANGELOG.md
index da7c4dbc..a7435530 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -25,6 +25,7 @@ The **patch** part changes is incremented if multiple releases happen the same m
 * lxc-solr: set homedir and port at install
 * minifirewall: whitelist deb.freexian.com
 * redis: some values should be quoted
+* redis: variable to disable transparent hugepage (default: do nothing)
 * squid: whitelist deb.freexian.com
 
 ### Fixed
diff --git a/redis/defaults/main.yml b/redis/defaults/main.yml
index 1a86c95c..b5547597 100644
--- a/redis/defaults/main.yml
+++ b/redis/defaults/main.yml
@@ -61,5 +61,9 @@ redis_sentinel_install: False
 
 redis_default_server_disabled: False
 
+# Set to Null to leave as is
+# Set to "always", "madvise" or "never" for custom value
+redis_sysctl_transparent_hugepage_enabled: Null
+
 general_alert_email: "root@localhost"
 log2mail_alert_email: Null
diff --git a/redis/handlers/main.yml b/redis/handlers/main.yml
index d85dcbf8..6d870b39 100644
--- a/redis/handlers/main.yml
+++ b/redis/handlers/main.yml
@@ -23,3 +23,8 @@
   service:
     name: log2mail
     state: restarted
+
+- name: restart sysfsutils
+  service:
+    name: sysfsutils
+    state: restarted
diff --git a/redis/tasks/main.yml b/redis/tasks/main.yml
index 871ab3eb..d9a57bb2 100644
--- a/redis/tasks/main.yml
+++ b/redis/tasks/main.yml
@@ -3,7 +3,19 @@
 - set_fact:
     redis_restart_handler_name: "{{ redis_restart_if_needed | bool | ternary('restart redis', 'restart redis (noop)') }}"
 
-- name: Redis is installed.
+- name: Linux kernel overcommit memory setting is enabled
+  sysctl:
+    name: "vm.overcommit_memory"
+    value: "1"
+    sysctl_file: "/etc/sysctl.d/evolinux-redis.conf"
+    state: present
+    reload: yes
+
+- name: Customize Kernel Transparent Huge Page
+  include: thp.yml
+  when: redis_sysctl_transparent_hugepage_enabled is not none
+
+- name: Redis is installed
   apt:
     name:
       - redis-server
@@ -13,7 +25,7 @@
     - redis
     - packages
 
-- name: Redis Sentinel is installed.
+- name: Redis Sentinel is installed
   apt:
     name: "redis-sentinel"
     state: present
@@ -22,14 +34,6 @@
     - packages
   when: redis_sentinel_install | bool
 
-- name: Linux kernel overcommit memory setting is enabled
-  sysctl:
-    name: "vm.overcommit_memory"
-    value: "1"
-    sysctl_file: "/etc/sysctl.d/evolinux-redis.conf"
-    state: present
-    reload: yes
-
 - name: Get Redis version
   shell: "redis-server -v | grep -Eo '(v=\\S+)' | cut -d'=' -f 2 | grep -E '^([0-9]|\\.)+$'"
   changed_when: false
diff --git a/redis/tasks/thp.yml b/redis/tasks/thp.yml
new file mode 100644
index 00000000..7a0dce27
--- /dev/null
+++ b/redis/tasks/thp.yml
@@ -0,0 +1,34 @@
+---
+
+- name: sysfsutils is installed
+  apt:
+    name:
+      - sysfsutils
+    state: present
+  tags:
+    - redis
+    - packages
+    - kernel
+
+- name: Check possible values for THP
+  assert:
+    that: redis_sysctl_transparent_hugepage_enabled is in ['always', 'madvise', 'never']
+    msg: "redis_sysctl_transparent_hugepage_enabled has incorrect value : '{{ redis_sysctl_transparent_hugepage_enabled }}' not in ['always', 'madvise', 'never']"
+  tags:
+    - redis
+    - kernel
+
+- name: "Set THP to {{ redis_sysctl_transparent_hugepage_enabled }} at boot"
+  lineinfile:
+    path: /etc/sysfs.conf
+    line: kernel/mm/transparent_hugepage/enabled = {{ redis_sysctl_transparent_hugepage_enabled }}
+    regexp: "kernel/mm/transparent_hugepage/enabled"
+  tags:
+    - redis
+    - kernel
+
+- name: "Set THP to {{ redis_sysctl_transparent_hugepage_enabled }} for this boot"
+  shell: "echo '{{ redis_sysctl_transparent_hugepage_enabled }}' >> /sys/kernel/mm/transparent_hugepage/enabled"
+  tags:
+    - redis
+    - kernel
\ No newline at end of file