[ltp] memory problems ?

[Robert Hajime Lanning]

<quote who="Kacper Wysocki">
> Straight out of the help for High Memory Support, "CONFIG_NOHIGHMEM",
> in the 2.4.20 kernel:
>
> " If you are compiling a kernel which will never run on a machine with
> more than 960 megabytes of total physical RAM, answer "off" here
> (defaut choice and suitable for most users). This will result in a
> "3GB/1GB" split: 3GB are mapped so that each process sees a 3GB virtual
> memory space and the remaining part of the 4GB virtual memory space is
> used by the kernel to permanently map as much physical memory as
> possible.
> If the machine has between 1 and 4 Gigabytes physical RAM, then answer
> "4GB" here."
>
> I don't know if this is your problem, but I need CONFIG_NOHIGHMEM="4GB"
> on my 1GB RAM machine to be able to use the full 1024MB.
> A second possibility would be that your new RAM module is damaged. This
> could happen, even with brand new ones.
> Cheers,
> 	Kacper

That would not cause the symtoms he is having.  If you have HIGHMEM turned
off, you just will not have 1024MB of ram.  The kernel will "see" 896MB.
This has to do with how kernel memory is mapped to the upper 1 gig of
address space in a process.

Ok, I just took Ted's Usenix Linux kernel tutorial on Monday. :)

Random processes dying like that would most likely be caused by either
an overheated CPU or by bad memory.  I have had both issues on my normal
PC.  (Overheated 486DX4-100, and, most receintly, a memory stick in my
new Athlon.)


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