#!/bin/bash
#
# from: https://docs.mongodb.com/v3.6/tutorial/transparent-huge-pages/
#

cat >/etc/systemd/system/disable-transparent-huge-pages.service<<EOF
[Unit]
Description=Disable Transparent Huge Pages (THP)
DefaultDependencies=no
After=sysinit.target local-fs.target
Before=mongod.service

[Service]
Type=oneshot
ExecStart=/bin/sh -c 'echo never | tee /sys/kernel/mm/transparent_hugepage/enabled > /dev/null'
ExecStart=/bin/sh -c 'echo never | tee /sys/kernel/mm/transparent_hugepage/defrag > /dev/null'

[Install]
WantedBy=basic.target
EOF

echo "/sys/kernel/mm/transparent_hugepage/enabled" 
cat /sys/kernel/mm/transparent_hugepage/enabled
echo "/sys/kernel/mm/transparent_hugepage/defrag"
cat /sys/kernel/mm/transparent_hugepage/defrag

systemctl enable disable-transparent-huge-pages
systemctl start disable-transparent-huge-pages

echo "/sys/kernel/mm/transparent_hugepage/enabled" 
cat /sys/kernel/mm/transparent_hugepage/enabled
echo "/sys/kernel/mm/transparent_hugepage/defrag"
cat /sys/kernel/mm/transparent_hugepage/defrag