16GB RAM not recognized
 

All,


I have a user who's only seeing 11 of his 16GB RAM after boot. This is FC6 x86_64.

uname-a =

2.6.19-1.2911.fc6 #1 SMP Sat Feb 10 15:16:31 EST 2007 x86_64 x86_64 x86_64 GNU/Linux

It states quite clearly in /var/log/messages (below) that I'm not getting it all. You can see that I specify 16GB on the kernel boot line.

Any susggestions on how to get the other 5GB?

Thanks


Feb 22 10:52:58 coil3 kernel: Kernel command line: mem=16000m ro root=LABEL=/1 rhgb
Feb 22 10:52:58 coil3 kernel: Memory: 11077076k/16384000k available (2468k kernel code, 211048k reserved, 1938k data, 312k init)
Feb 22 10:52:58 coil3 kernel: Freeing initrd memory: 1606k freed
Feb 22 10:52:58 coil3 kernel: MEM window: fa700000-fa8fffff
Feb 22 10:52:58 coil3 kernel: MEM window: fa500000-fa6fffff
Feb 22 10:52:58 coil3 kernel: MEM window: f9c00000-fa4fffff
Feb 22 10:52:58 coil3 kernel: MEM window: faa00000-feafffff
Feb 22 10:52:58 coil3 kernel: Total HugeTLB memory allocated, 0
Feb 22 10:52:58 coil3 kernel: Non-volatile memory driver v1.2
Feb 22 10:52:58 coil3 kernel: Freeing unused kernel memory: 312k freed
Feb 22 10:52:58 coil3 kernel: ohci_hcd 0000:03:00.0: irq 19, io mem 0xfa8fd000
Feb 22 10:52:58 coil3 kernel: ohci_hcd 0000:03:00.1: irq 19, io mem 0xfa8fe000

You may need to recompile the kernel.
I can't think of the exact parameter right know but, there a setting for max memory.

I found this on google, the first link...
http://kerneltrap.org/node/2450

Scroll down to:
HIGHMEM solution for using 64 GB of memory

maybe more?
 

All,

Well thanks for the help so far, but maybe somebody else can write in.

I realize I may have to recompile the kernel, but can't do that unless the unremembered parameter is...um...remembered. Better yet, if someone can tell me where to research it, I'll find out myself and post the answer here.

As for the kernel article, it was interesting reading, but it's strictly about 32-bit architectures, and as I said, this is 64-bit Fedora.

Any other advice?

Regards...

Parameters should be the same.

You are looking to recompile with BIGMEM support ie >4GB.

The parameter you are after is CONFIG_HIGHMEM64G according to this thread.

The procedure for compiling the Linux kernel is generally the same whether you are running a 32 bit, 64 bit or any other supported architecture. There is a guide that may help you compile kernels specifically for Fedora Core.