Re: vmalloc kernel parameter

[Rodrigo Amestica <ramestic@nrao.edu>]

Hi Sergey, many thanks for the reply.

I saw those links before but I did not get their full meaning.

By setting uppermem to 512M it does actually work. However, now I'm trying to 
reserve RAM for DMA sake. For that I use mem=1899M; where 1899 comes from the 
total memory reported under normal booting less 128M, which are the Megs that 
I'm trying to reserve.

It seems that by adding mem to the boot line goes into conflicting with the 
uppermem+vmalloc arrangement.

Without providing more details on what's actually happening can you tell that 
there is something wrong on what I'm trying to do?

Would switching to lilo help any?

thanks,
  Rodrigo

Sergey Vlasov wrote:
> 
> This is a known problem with GRUB: it tries to put initrd at the highest
> possible address in memory, and assumes the standard vmalloc area size.
> You need to trick GRUB into thinking that your machine has less memory
> by using "uppermem 524288" (512M) or even lower - then the initrd data
> will still be accessible for the kernel even with larger vmalloc area.
> 
> http://lkml.org/lkml/2005/4/4/283
> http://lists.linbit.com/pipermail/drbd-user/2005-April/002890.html
> 
>> ps: my kernel version is 2.6.15.2, and my machine is a dual opteron
>> with 2GB of ram
>>
>> title with vmalloc
>>          root (hd0,0)
> 
> Add "uppermem 524288" here.
> 
>>          kernel /boot/vmlinuz ro root=LABEL=/ vmalloc=256M
>>          initrd /boot/initrd.img