Hi there,
It seems like the bios of this machine doesn't have any type of configuration regarding the memory mapping. I'm already using the kernel-hugemem , but the problem remains. What else can be done?
By the way, if the machine had more than one cpu, the problem would remain?
Best regards, Bruno Sousa
-----Mensagem original----- De: centos-bounces@centos.org [mailto:centos-bounces@centos.org] Em nome de James Pearson Enviada: quinta-feira, 22 de Junho de 2006 15:54 Para: CentOS mailing list Assunto: Re: [CentOS] x86 uniprocessor 4GB memory
Bruno Sousa wrote:
Hi there,
I'm currently using CentOS 4.3 (Server edition) in a HP DC 5100 with the IntelR 915GV chipset, powered by a PIV 3.0GHZ.
Now I'm facing a problem, with memory.
I got myself 4GB of memory, the system bios detects it correctly, but in Linux can only see around 3.5gb memory. With the default kernel-smp (I use hyperthread) or with kernel-hugemem , I have the same results.
Is there any way to workaround this issue?
It is probably the 4Gb memory hole issue - various 'things' reserve memory below 4GB so hiding the real memory from the OS.
Your BIOS may have a mapping option to map some of this hidden real memory to above 4Gb - however, you need to use a hugemem kernel to access this memory.
Having multiple CPUs would make no difference. The hugemem kernel would only see this memory if the BIOS could map it to above 4Gb - if the BIOS can't, then there is nothing above 4Gb for the hugemem kernel to see.
A newer version of the BIOS _might_ have added this support ...
James Pearson