How can I configure hugepages in Red Hat Enterprise Linux?
Environment
- Red Hat Enterprise Linux (RHEL) 5 or later
Issue
- How can I configure hugepages in Red Hat Enterprise Linux?
Resolution
Preferred method for RHEL 10
The instructions are included in RHEL10 product documentation.
Preferred method for RHEL 9
The instructions are included in RHEL9 product documentation.
Preferred method for RHEL 5, 6, 7, 8
Use the hugepages=X
kernel parameter to set X number of huge pages.
[root@rhel7 ~]# cat /proc/cmdline
BOOT_IMAGE=/vmlinuz-3.10.0-1127.el7.x86_64 root=/dev/mapper/rhel_rhel7-root ro crashkernel=auto spectre_v2=retpoline rd.lvm.lv=rhel_rhel7/root rd.lvm.lv=rhel_rhel7/swap rhgb quiet hugepages=10
[root@rhel7 ~]# cat /proc/sys/vm/nr_hugepages
10
Huge page reservations are allocated from free and contiguous RAM. By using this method the allocation happens early in the boot process where memory is much more likely to be free and contiguous.
See also:
- How do I permanently modify the kernel command line in RHEL5 and RHEL6?
- How do I permanently modify the kernel command line in RHEL7/8/9?
Alternate method:
Configure hugepages by using the kernel tunable vm.nr_hugepages
For example:
- Edit /etc/sysctl.conf file and specify the number of hugepages in the nr_hugepages :
vm.nr_hugepages = 10
- Execute sysctl command.
# sysctl -p <snip> vm.nr_hugepages = 10
-
Confirm in /proc/meminfo :
# cat /proc/meminfo | grep Huge HugePages_Total: 10 HugePages_Free: 10 HugePages_Rsvd: 0 Hugepagesize: 2048 kB
Note : It's recommended to restart the system after configuring hugepages as the chances of having free contiguous memory (for hugepages allocation) is much greater when a system is started.
Comments
- For more details check the kernel documentation at :
/usr/share/doc/kernel-doc-2.6.18/Documentation/vm/hugetlbpage.txt
Note: The above file is provided by the kernel-doc
package.
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Comments