Free page lower limit

Richard B. Johnson (root@chaos.analogic.com)
Tue, 2 Feb 1999 08:59:59 -0500 (EST)


The following, between two systems using Linux 2.2.1:

mount skunkworks:/ /mnt
tar -clf /dev/null /mnt

Eventually results in a low memory situation on the serving node.
This prevents login from executing.

If a task remains logged in, `cat proc/meminfo` shows more and
more swap being used, plus less and less free memory. Eventually
I get a "can't fork" error. The problem seems to be when the
free pages get below 740k. This is the last number I am able to
see before the "can't fork" error.

The problem is reversible, i.e., there doesn't seem to be a memory
leak, only that the free pages are allowed to get a bit too low.
I think that if the lower limit is adjusted upwards a bit, this
problem will not exist.

FYI, changes in 'mm' improved the performance. A kernel compile
now takes 120 seconds, down from 300.

Cheers,
Dick Johnson
***** FILE SYSTEM WAS MODIFIED *****
Penguin : Linux version 2.2.1 on an i686 machine (400.59 BogoMips).
Warning : It's hard to remain at the trailing edge of technology.
Wisdom : It's not a Y2K problem. It's a Y2Day problem.

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