Transparent Hugepage is not getting disabled (Doc ID 2279458.1)

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APPLIES TO:

Linux OS - Version Oracle Linux 6.8 with Unbreakable Enterprise Kernel [4.1.12] and later
Information in this document applies to any platform.

SYMPTOMS

Trying to disable transparent hugepages. Made the following entries:

            /etc/grub.conf 
           
           kernel /vmlinuz-2.6.32-642.3.1.el6.x86_64 ro root=/dev/mapper/vg_ho02db02-lv_root rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=auto rd_LVM_LV=vg_ho02db02/lv_swap rd_LVM_LV=vg_ho02db02/lv_root KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet numa=off transparent_hugepage=never fnic.fnic_max_qdepth=256

            /etc/rc.d/rc.local： 
           
           if test −f /sys/kernel/mm/transparent_hugepage/enabled; then 
           
           echo never > /sys/kernel/mm/transparent_hugepage/enabled 
           
           fi 
           
           if test −f /sys/kernel/mm/transparent_hugepage/defrag; then 
           
           echo never > /sys/kernel/mm/transparent_hugepage/defrag 
           
           fi

Even though the changes have been made the system still shows hugepage is active

CAUSE

The ktune service enables transparent_hugepages by default for all profiles hence anytime a tuned profile is enabled at bootup or manually transparent huge pages gets re-enabled.

The below file states the cause of the hugepage getting enabled always even though it is set to never in grub.conf file
/etc/tune-profiles/enterprise-storage/ktune.sh

            #!/bin/sh 
           
. /etc/tune-profiles/functions 
           
start() { 
           
  set_cpu_governor performance 
           
  set_transparent_hugepages always ---->>>> set transparent_hugepages always 
           
  disable_disk_barriers 
           
  multiply_disk_readahead 4 
           
  return 0 
           
} 
           
stop() { 
           
  [ "$1" != "restart" ] && restore_cpu_governor 
           
  restore_transparent_hugepages 
           
  enable_disk_barriers 
           
  restore_disk_readahead 
           
  return 0 
           
} 
           
process $@

SOLUTION

            #service tuned stop 
           
#chkconfig tuned off 
           
#service ktune stop 
           
#chkconfig ktune off

Append transparent_hugepage=never to kernel command line in /boot/grub/grub.conf file

            /etc/grub.conf: 
           
... 
           
kernel /vmlinuz-2.6.32-642.3.1.el6.x86_64 ro root=/dev/mapper/vg_ho02db02-lv_root rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=auto rd_LVM_LV=vg_ho02db02/lv_swap rd_LVM_LV=vg_ho02db02/lv_root KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet numa=off 
           transparent_hugepage=never 
            fnic.fnic_max_qdepth=256 
           
... 
          

Reboot the server and check if /sys/kernel/mm/transparent_hugepage/enabled changed

            #cat /sys/kernel/mm/transparent_hugepage/enabled 
           
           always madvise [never]