In the list of options, find the kernel line - that is, the line beginning with the keyword `linux` (or, in some cases, `linux16`). Append the following option to the end of this line:
Replace _xx_ with the amount of RAM you have in megabytes.
Wait for the system to boot and log in. Then, open a command line and execute the [command]#free -m# command again. If total amount of RAM displayed by the command matches your expectations, append the following to the line beginning with `GRUB_CMDLINE_LINUX` in the `/etc/default/grub` file to make the change permanent:
After you updated the file and saved it, refresh the boot loader configuration so that the change will take effect. Run the following command with root privileges:
In `/etc/default/grub`, the above example would look similar to the following:
GRUB_DISTRIBUTOR="$(sed 's, release.*$,,g' /etc/system-release)"
GRUB_CMDLINE_LINUX="rd.lvm.lv=rhel/root vconsole.font=latarcyrheb-sun16 rd.lvm.lv=rhel/swap $([ -x /usr/sbin/rhcrashkernel.param ] && /usr/sbin/rhcrashkernel-param || :) vconsole.keymap=us rhgb quiet mem=1024M"