环境

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

问题

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

决议

Follow the steps below

  2. 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.

    Raw
    GRUB_CMDLINE_LINUX="rd.lvm.lv=rhel/root rd.lvm.lv=rhel/swap ... transparent_hugepage=never"
  1. 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​​
  1. Reboot the system and verify option has been added
  • Reboot the system

    Raw
    # shutdown -r now
  • Verify the parameter is set correctly

    Raw
    # 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:

    Raw
    # tuned-adm active Current active profile: throughput-performance
  • To create customized profile, create a new directory in /etc/tuned directory with desired profile name.

    Raw
    # mkdir /etc/tuned/myprofile-nothp
  • Then create a new tuned.conf file for myprofile-nothp, and insert the new tuning info:

    Raw
    # cat /etc/tuned/myprofile-nothp/tuned.conf [main] include= throughput-performance [vm] transparent_hugepages=never
  • Make the script executable:

    Raw
    # chmod +x /etc/tuned/myprofile-nothp/tuned.conf
  • Enable myprofile like so:

    Raw
    # 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:

    Raw
    # cat /sys/kernel/mm/transparent_hugepage/enabled
  • Option 2: (Alternative) Disable tuned services
  • This resolution will disable the tuned services.

    Raw
    # systemctl stop tuned # systemctl disable tuned
  • OR

    Raw
    # 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.