FC3 max memory

[Rick Stevens]

Tony Dietrich wrote:
> On Wednesday 02 Mar 2005 21:44, Alexander Lazarevich wrote:
> 
>>[root at blah root]# uname -a
>>Linux blah 2.6.10-1.741_FC3smp #1 SMP Thu Jan 13 16:58:29 EST 2005 x86_64
>>x86_64 x86_64 GNU/Linux
>>
>>Hardware is Tyan 2885 mobo, two opteron 244 procs in it. Right now the
>>system has 4GB of memory installed:
>>
>>[root at hofmann license]# cat /proc/meminfo
>>MemTotal:      3607440 kB
>>
>>The mobo takes up to 16GB of memory. But when I add more memory, 4 more
>>1GB dimms, 8GB total, same exact type of memory that is already in the
>>system (DDR ECC Reg PC2700), the kernel panics and doesn't boot. The error
>>is:
>>
>><0> kernel panic - not syncing: Attempted to kill the idle task
>>
>>It dies just before the audit init takes place, so the kernel hardly boots
>>at all, if even.
>>
>>Any idea what the maximum memory is for FC3 with the kernel I have? I
>>tried looking for a bigmem kernel but isn't large memory support built in?
>>I'm pretty sure support is for much more memory than 4GB. Do I have to
>>recompile a special kernel though?

If you look at the "/boot/config-`uname -r`" file, you can see which
memory model you have.  The default one for FC3 on an i686 is 4GB:

# CONFIG_NOHIGHMEM is not set
CONFIG_HIGHMEM4G=y
# CONFIG_HIGHMEM64G is not set
CONFIG_HIGHMEM=y
CONFIG_HIGHPTE=y
# CONFIG_MATH_EMULATION is not set
CONFIG_MTRR=y
# CONFIG_EFI is not set
CONFIG_REGPARM=y

That's found somewhere around line 126 in the config file.

> Isn't there a bigmem kernel somewhere?  Or was that RH9 that had that?

RH7.x-9 had it, as well as RHEL (the "EL" kernels are set SMP, 64GB).
If you want a bigmem kernel, you'll have to build it yourself.

There are very few desktops out there with >4GB.  Servers, yes, but not
desktops and "out of the box" FC3 is really aimed at desktops.  As far
as "does it work?", I have built FC3 kernels for 8GB mobos
("CONFIG_HIGHMEM64G=y") and they work.
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- Rick Stevens, Senior Systems Engineer     rstevens at vitalstream.com -
- VitalStream, Inc.                       http://www.vitalstream.com -
-                                                                    -
-            I'm afraid my karma just ran over your dogma            -
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