[ltp] memory problems ?

[Fabrice Bellet]

On Fri, Jun 13, 2003 at 01:37:03AM -0700, Robert Hajime Lanning wrote:
> 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.)

You're right.

I enabled HIGHMEM (4GB) support in my custom kernel, and jumped from approx 
926000000 to 1058029568 total available memory. I'll have to stress the machine
a bit in this new configuration, but I doubt this'll make disappear my random
crashes. I'll keep you informed.

Moreover the memtest86 program doesn't have this compilation option, and can 
test memory above 1GB.

I have a long experience of problems with faulty memory chips. Basically, ALL
*noname* 512MB modules, with very few exceptions, that I put in my machines
were buggy on the long term. Some of them started causing problems after a few 
weeks (running 24/24 7/7), some were so buggy that I couldn't even enter the 
BIOS of the machine. Symptoms with Linux were always the same : random gcc 
crashes (internal error, signal 11, ...), random seg faults of userland apps, 
kernel oops (less frequent). Since these various bad experience, I stay with
chips from well known brands, possibly with ECC, to avoid these kind of 
problems...

-- 
fabrice