关于Linux的透明大页详细介绍

2019-10-14 10:46:19丽君

[root@getlnx06 ~]# vi /etc/grub.conf
# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE: You have a /boot partition. This means that
#   all kernel and initrd paths are relative to /boot/, eg.
#   root (hd0,0)
#   kernel /vmlinuz-version ro root=/dev/mapper/VolGroup--LogVol0-LogVol01
#   initrd /initrd-[generic-]version.img
#boot=/dev/sda
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title Red Hat Enterprise Linux 6 (2.6.32-504.el6.x86_64)
  root (hd0,0)
  kernel /vmlinuz-2.6.32-504.el6.x86_64 ro root=/dev/mapper/VolGroup--LogVol0-LogVol01 rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=auto rd_LVM_LV=VolGroup-LogVol0/LogVol01 rd_LVM_LV=VolGroup-LogVol0/LogVol00 KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet
  initrd /initramfs-2.6.32-504.el6.x86_64.img
transparent_hugepage=never

 

方法2:设置/etc/rc.local文件

[root@getlnx06 ~]# vi /etc/rc.local
#!/bin/sh
#
# This script will be executed *after* all the other init scripts.
# You can put your own initialization stuff in here if you don't
# want to do the full Sys V style init stuff.
 
touch /var/lock/subsys/local
 
if test -f /sys/kernel/mm/redhat_transparent_hugepage/enabled; then
 echo never > /sys/kernel/mm/redhat_transparent_hugepage/enabled
fi

使用上面的配置后必须重启操作系统才能生效,你也可以运行下面命令不用重启操作系统。

You must reboot your system for the setting to take effect, or run the following two echo lines to proceed with the install without rebooting:

[root@getlnx06 ~]# echo never > /sys/kernel/mm/redhat_transparent_hugepage/enabled
[root@getlnx06 ~]# cat /sys/kernel/mm/redhat_transparent_hugepage/enabled
always madvise [never]
[root@getlnx06 ~]# 

小知识点:

1:从RedHat 6, OEL 6, SLES 11 and UEK2 kernels 开始,系统缺省会启用 Transparent HugePages :用来提高内存管理的性能透明大页(Transparent HugePages )和之前版本中的大页功能上类似。主要的区别是:Transparent HugePages 可以实时配置,不需要重启才能生效配置;

 

2:Transparent Huge Pages在32位的RHEL 6中是不支持的。

Transparent Huge Pages are not available on the 32-bit version of RHEL 6.

 

3: ORACLE官方不建议我们使用RedHat 6, OEL 6, SLES 11 and UEK2 kernels 时的开启透明大页(Transparent HugePages ), 因为透明大页(Transparent HugePages ) 存在一些问题:

        a.在RAC环境下 透明大页(Transparent HugePages )会导致异常节点重启,和性能问题;