[PLUG] Resolved: Bigmem not recognizing memory

[Bill Barry]

On Tue, Jul 22, 2008 at 1:53 PM, Bill Barry <barryb at proaxis.com> wrote:
> I recently added 4GB of ram to a machine that already had 2GB for a total of
> 6GB of memory, but I only see 4GB in  /proc/meminfo.  The bios shows that
> the memory is recognized and is functioning, but something is still wrong.
> Here is some relavant information.
>
> :~# cat /proc/meminfo
> MemTotal:      4117296 kB
> MemFree:        405400 kB
>
> I am using a stock Debian bigmem kernel:
>  2.6.25-2-686-bigmem.
>
> The processor is:
> CPU1: AMD Athlon(tm) 64 X2 Dual Core Processor 4000+ stepping 01
>
> The motherboard is:
> ASUS M2NPV-VM GF6150 AM2
>
> Thanks for any help,
> Bill Barry
>
>

Well, I finally figured out what why I could only access 4GB of my 6GB
of memory.  It turned out that I had installed the memory wrong. This
motherboard has 4 memory slots in 2 banks, A and B. I had installed 2
1GB DIMMs in bank A and 2 2GB DIMMs in bank B, but as a last resort I
read the manual  which says that A1+B1 must equal A2+B2, i.e. I had to
install 3 GB in each bank to make them symmetric.   So the bigmem
kernel does work, I can access 6GB with a 32 bit kernel, with each
process  limited to less than 4GB. As part of  trying to find out
where the problem was I also installed a partition with a 64 bit
kernel and I am slowly migrating everything over to that.

Thanks Alan, Jason, Drew and Derek for your suggestions.

Bill