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* LowFree/LowMem problem
@ 2008-01-21  5:32 Matthias Wolle
  2008-01-23 22:06 ` Andrew Morton
  0 siblings, 1 reply; 6+ messages in thread
From: Matthias Wolle @ 2008-01-21  5:32 UTC (permalink / raw)
  To: linux-kernel

Hi,

my company is running several servers with kernel 2.6.23.12.  This are Dual 
Quad Core servers (CPU Intel) with 16GB RAM using a 32Bit kernel.
After some days nicely running the oom killer killed our processes.
Our research discovered that the free low memory was reduced to about 11MB. We 
found out that the decreasing of low memory is related to the count off 
executed and ended programs.

I could reproduce the same bug on a maschine with 2GB RAM without PAE (option 
4GB HIGHMEM). The following code reproduces the bug.

#!/bin/sh

while [ true ]; do
	cat /proc/meminfo| grep LowFree
done

Please run this script only on a test system. It reduces the low memory quite 
fast (within minutes). 

The latest available kernel 2.6.24-rc8 is also affected.

Please fell free to request more information from me.
Please always CC to me, I'm not subscribed.

Thanks for reading

Matthias

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: LowFree/LowMem problem
@ 2008-01-21 16:45 Parag Warudkar
  0 siblings, 0 replies; 6+ messages in thread
From: Parag Warudkar @ 2008-01-21 16:45 UTC (permalink / raw)
  To: Matthias.Wolle; +Cc: LKML

Matthias Wolle <Matthias.Wolle <at> gmx.de> writes:

>
> Hi,
>
> my company is running several servers with kernel 2.6.23.12.  This are Dual
> Quad Core servers (CPU Intel) with 16GB RAM using a 32Bit kernel.

This is a common problem with running 32-bit kernels with more than 8Gb RAM.
(Search the archives and you will find similar problem reports.)

Anyone in your situation has two options - Preferred one is to switch
to a 64-bit kernel. In most cases you can just upgrade the kernel to
64-bits and use the same 32-bit userspace. It works fine.

If you cannot for some reason upgrade to a 64-bit kernel, the second
option is to try and use RHEL/CentOS kernels which according to Alan
Cox are better tuned for this kind of setup and you have a better
chance that they will work.

HTH

Parag

^ permalink raw reply	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2008-01-25  1:45 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2008-01-21  5:32 LowFree/LowMem problem Matthias Wolle
2008-01-23 22:06 ` Andrew Morton
2008-01-23 22:40   ` Matthias Wolle
2008-01-24  7:16     ` Andi Kleen
2008-01-25  1:45       ` Matthias Wolle
2008-01-21 16:45 Parag Warudkar

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