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Re: [OCLUG-Tech] Machine becomes unresponsive when allocated large amounts of memory

  • Subject: Re: [OCLUG-Tech] Machine becomes unresponsive when allocated large amounts of memory
  • From: Martin Hicks <mort [ at ] bork [ dot ] org>
  • Date: Mon, 13 Feb 2006 09:11:07 -0500
On Sun, Feb 12, 2006 at 07:55:16PM -0800, tiller man wrote:
> For the last few weeks, I have been allocating extremely large amounts  of memory in the programs I have been writing. I keep running into the  same problem.

For someone's definition of "extremely large" :-)

>   Now, I currently access this machine(AMD64 with 1GB of memory I  believe) through ssh, as it is not located directly at my workplace.  After the process has allocated a certain amount of memory, I can't  kill it, as it is completely unresponsive. I can't open another ssh  session with the machine either. I just get no response from anything.  As a result, I have to email someone working next to the machine to  tell them to restart the machine every time this happens.

You're right that You should be able to allocate more memory than is
physically present in the machine, up to a theoretical total of
physical+swap.  In practise this isn't always true.  The Linux Virtual
memory manager sometimes has a little snit and won't do it.  It just
becomes unresponsive and slow.

>   Linux pot1 2.4.21-37.ELsmp #1 SMP Wed Sep 7 13:32:18 EDT 2005 x86_64 x86_64 x86_
>   64 GNU/Linux

Oh good lord.  2.4 is totally useless for allocating more than physical
memory.  If you want any hope then upgrade to a latest 2.6 kernel.  When
I was at SGI we had no end of problems dealing with large memory
configurations on Altix.


Martin Hicks || mort [ at ] bork [ dot ] org || PGP/GnuPG: 0x4C7F2BEE

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