RedHatAS4 Kernel configuration change and re-compile

I. kernel memory configuration check: --------------------- you can use the following methods to check whether the kernel supports 64 GB memory at startup. First, you must find out which kernel is used at startup [root @ study ~] # Cat/boot/grub. conf... default = 0 (indicating that the first entry is started by default) timeout = 5 splashimage = (hd0, 0)/grub

I. kernel memory configuration check:

-----------------------

You can use the following method to check whether the kernel supports 64 GB memory at startup.

First, find out which kernel is used during startup

[Root @ study ~] # Cat/boot/grub. conf

...

Default = 0 (indicating that the first entry is started by default)

Timeout = 5

Splashimage = (hd0, 0)/grub/splash.xpm.gz

Hiddenmenu

Title Red Hat Enterprise Linux AS (2.6.9-34. ELsmp)

Root (hd0, 0)

Kernel/vmlinuz-2.6.9-34.ELsmp ro root =/dev/VolGroup00/LogVol00 rhgb quiet

Initrd/initrd-2.6.9-34.ELsmp.img

Title Red Hat Enterprise Linux AS-up (2.6.9-34.EL)

Root (hd0, 0)

Kernel/vmlinuz-2.6.9-34.EL ro root =/dev/VolGroup00/LogVol00 rhgb quiet

Initrd/initrd-2.6.9-34.EL.img

My kernel is vmlinuz-2.6.9-34.ELsmp

The corresponding kernel compilation file during installation is

/Boot/config-2.6.9-34.ELsmp

Check high memory support

[Root @ study ~] # More/boot/config-2.6.9-34.ELsmp | grep 4G

# CONFIG_X86_4G is not set

# CONFIG_X86_4G_VM_LAYOUT is not set

# CONFIG_HIGHMEM4G is not set

CONFIG_HIGHMEM64G = y indicates that 64 GB memory is selected during kernel compilation,

Only 4G Support is similar:

[Root @ study ~] # More/boot/config-2.6.9-34.EL | grep 4G

# CONFIG_X86_4G is not set

# CONFIG_X86_4G_VM_LAYOUT is not set

CONFIG_HIGHMEM4G = y

# CONFIG_HIGHMEM64G is not set