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SubjectRe: lost memory on a 4GB amd64
On Sun, 19 Sep 2004, Jon Masters (JM) wrote:

JM> On Sun, 19 Sep 2004 00:18:38 +1000 (EST), Sergei Haller
JM>
JM> > * if the memory configuration is as follows: the first 3gb ar at the
JM> > normal address range, the fourth gb is at the address range 4-5gb.
JM> > then all 4gb are available (not quite -- a few mb ere missing, but
JM> > thats ok) and
JM> > - the SMP kernel panics as soon as I start X
JM>
JM> Just out of interest - can you say what tests you ran here - for
JM> example whether you tried allocating large amounts of memory from a
JM> userspace process without running X and/or touching bits of memory
JM> mapped hardware? You say a kernel compile works fine so can you rule
JM> out this being X taking down the system (you're previous mail seemed
JM> somehat unclear).
- as soon as I start X, the machine is gone.
- if I compile the kernel (without X of course) its ok.

the machine is supposed to be for scientific calculations and we run magma
on it. The test I ran is just a one-liner which creates a matrix of size
20000x20000 with zeros in it. so basically it just allocates 1.6gb of
memory and writes zeros in it. the SMP kernel with the above memory
configuration crashes immediately.
I guess I should write a simple C-program using malloc or something to
reproduce the crash in the simplest possible way, shouldn't I?

Sergei
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