Re: 2.6.11 kernel can't see 4GB?

[Koen Tavernier <koen@ipec.co.uk>]

Lennart Sorensen wrote:

> On Tue, May 17, 2005 at 01:35:28PM +0100, Koen Tavernier wrote:
>  
>
> > I've been running a dual opteron box with 2GB for a few days. Today I 
> > added 2GB to the box, all recognised by the motherboard, but after 
> > booting into linux (with the stock 2.6.11 debian kernel) free only 
> > reports 3344996 Kb. I thought the 64 bit kernel avoided all problems 
> > with having lots of memory? Or should I pass the kernel a parameter?
> >
> > I had a quick search through the list but couldn't see anything relevant.
> >    
>
> Does your bios have an option for mapping memory from 3-4GB up to 4-5GB
> so the PCI memory hole at 3-4GB won't overlap with it?
>
> This is sometimes called a memory hole (and you want to make one).
>
> The kernel can then use all the memory since 4GB is not a limit for it.
>
> Len Sorensen
>  
This was in deed the culprit! Once you had mentioned the memory hole I 
was able to find a lot more information on this. Setting the memory hole 
mapping to [Software] on the Tyan motherboard gave me 4GB immediately.

Thanks a lot for your help!

Koen.