I just upgraded my system RAM from 1 GB (2x 512 MB) to 1.5 GB (512 MB + 1
GB). However, when I boot into a custom compiled kernel (2.6.21-5 with the
tuxonice/suspend2 patch), I see the memory is unchanged (free -m reports
884 MB). When I boot into a vanilla Debian kernel (2.6.21-2), I see the
full 1.5 GB (free -m reports 1510 MB). Needless to say, the BIOS also
reports the full 1.5 GB. I do not remember hardwiring the total memory
anywhere during the compilation of that kernel. Further, the grub boot line
is unremarkable in either case.

The system feels snappier when I use the Debian vanilla kernel (indicating
that it is really seeing more RAM and I do not simply have a kernel
dependent bug in free -m).

Any suggestions to see where things are going awry ?

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On Wed, 18 Jul 2007 22:18:45 -0700, Geico Caveman wrote:

> I just upgraded my system RAM from 1 GB (2x 512 MB) to 1.5 GB (512 MB + 1
> GB). However, when I boot into a custom compiled kernel (2.6.21-5 with the
> tuxonice/suspend2 patch), I see the memory is unchanged (free -m reports
> 884 MB). When I boot into a vanilla Debian kernel (2.6.21-2), I see the
> full 1.5 GB (free -m reports 1510 MB). Needless to say, the BIOS also
> reports the full 1.5 GB. I do not remember hardwiring the total memory
> anywhere during the compilation of that kernel. Further, the grub boot
> line is unremarkable in either case.
>
> The system feels snappier when I use the Debian vanilla kernel (indicating
> that it is really seeing more RAM and I do not simply have a kernel
> dependent bug in free -m).
>
> Any suggestions to see where things are going awry ?

My first guess would be that you did not CONFIG_HIGHMEM when you compiled
your custom kernel. However, I'm not familiar with that patch, so I might
not be correct. Seems to act like not configured in kernel, though.

Rodney

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