[Systems] Load on treehouse

Bernie Innocenti bernie at codewiz.org
Wed Sep 29 05:09:07 EDT 2010

On 09/29/10 09:23, Sascha Silbe wrote:
> I have no idea whether it might eat my firstborn some day, but it
> definitely does churn CPU, making the system so horribly slow that a
> hard reset is often the only option.

Were you working near the limit of physical memory?  High CPU usage is
what happens when the system is constantly scanning virtual memory to
find pages that could be evicted. Eventually, it will start dropping
cached files, including running programs and libraries, causing a lot of
disk I/O. Adding some swap would help this situation by paging out
rarely used data and thus lowering the pressure on the VM system.

If you have twice the physical memory for your working set, this problem
should never happen.

> I don't remember if I had overcommit accounting turned off on the
> (many) systems where I encountered it (over the last decade, including
> as recently as last year).
> I usually configure a small swap place, even if just a RAM disk. This
> allows the OOM to kick in and everything works fine (enough).

Have you tried posting a reproducible test case to the lkml? Sounds like
a kernel bug to me.

A lot of Linux systems run with no swap at all, including all embedded
devices and some servers. It would be a shame if this did not work.

   // Bernie Innocenti - http://codewiz.org/
 \X/  Sugar Labs       - http://sugarlabs.org/

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