How to disable transparent hugepages (THP) on Red Hat Enterprise Linux 7, 8

原文链接：https://access.redhat.com/solutions/1320153

环境

• Red Hat Enterprise Linux 7, 8
• transparent hugepages (THP)
• tuned

问题

• How to disable transparent hugepages (THP) on Red Hat Enterprise Linux 7, 8
• Disabling transparent hugepages (THP) on Red Hat Enterprise Linux 7 is not taking effect.

决议

Follow the steps below

1. Add the “transparent_hugepage=never” kernel parameter option to the grub2 configuration file.
   • Append or change the “transparent_hugepage=never” kernel parameter on the GRUB_CMDLINE_LINUX option in /etc/default/grub file. Only include the parameter once.GRUB_CMDLINE_LINUX="rd.lvm.lv=rhel/root rd.lvm.lv=rhel/swap ... transparent_hugepage=never"
2. Rebuild the /boot/grub2/grub.cfg file by running the grub2-mkconfig -o command as follows:
   • Please ensure to take a backup of the existing /boot/grub2/grub.cfg before rebuilding.
     • On BIOS-based machines: ~]# grub2-mkconfig -o /boot/grub2/grub.cfg
     • On UEFI-based machines: ~]# grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg
3. Reboot the system and verify option has been added
   • Reboot the system# shutdown -r now
   • Verify the parameter is set correctly# cat /proc/cmdline

If Transparent Huge Pages (THP) is still not disabled, continue and use one of the options below.

• Option 1: (Recommended) create a customized tuned profile with disabled THP
  • With this resolution we will create a customized version of the currently running profile. The customized version will disable THP.
  • Find out which profile is active, create a copy. In the following example we currently use the throughput-performance profile:# tuned-adm active Current active profile: throughput-performance
  • To create customized profile, create a new directory in /etc/tuned directory with desired profile name.# mkdir /etc/tuned/myprofile-nothp
  • Then create a new tuned.conf file for myprofile-nothp, and insert the new tuning info:# cat /etc/tuned/myprofile-nothp/tuned.conf

# cat /etc/tuned/myprofile-nothp/tuned.conf 
[main]
include=throughput-performance

[vm]
transparent_hugepages=never

Make the script executable:

# chmod +x /etc/tuned/myprofile-nothp/tuned.conf 

Enable myprofile like so:

# tuned-adm profile myprofile-nothp

This change will immediately take effect and persist reboots.

To verify if THP are disabled or not, run below command:

# cat /sys/kernel/mm/transparent_hugepage/enabled

Option 2: (Alternative) Disable tuned services

• This resolution will disable the tuned services.# systemctl stop tuned # systemctl disable tuned
• OR# tuned-adm off
• Now add “transparent_hugepage=never” kernel parameter in grub2 configuration file as explained in steps 1-3 above.
• Reboot the server for changes to take effect.