[PLUG] Memory leak???

Brent Jones brent at servuhome.net
Sat Dec 15 21:05:09 UTC 2007


On 12/15/07, Kurt Sussman <plug at merlot.com> wrote:
>
> someone (plug_1 at robinson-west.com) typed this ...
> > On a CentOS 4.3 box yum  updated to 4.4 I have been watching the free
> store
> > via top and have been noticing it going down throughout the day.  I've
> had
> > to shut this box off the hard way a couple of times because it was
> thrashing.
> > Question is, what's the culprit?
>
> First, let's change the question.
>
> What is the problem?
>
> Is the load going up? Is daemon response measurably slower? Are
> processes dropping core dumps?
>
> > Why isn't the swap space being used?
>
> Because the system hasn't run out of RAM.
>
> Free memory can show as little as 5M. That doesn't mean the system is in
> a low-memory state.
>
> > Is there a way to do garbage collection or otherwise get the memory back
> > before the system starts to thrash?
>
> Define (and describe) 'thrash'. As Rogan said, if there's no swap usage,
> there can be no thrashing.
>
> --Kurt
> --
> ----------------------------------------------------------------------
>     Merlot Research Group, Inc               http://www.merlot.com
>     kls[at]merlot.com        GPG key 82505A74       GTalk: ratbelt
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The linux kernel is better at memory management than you'd think. It won't
reclaim memory until another program needs it, for the most part. "Free"
memory is a bit if a misleading term, you'll want to identify how much your
processes are using, not what 'top' says is free, since the two are pretty
different.
Thrashing could occur for any number of reasons as well, you listed quite a
few services running on that system, as well as mentioned it being a CD
server. Chances are, any 'thrashing' thats occuring is just normal disk
access loading up program data.
Hard drive activity is normal  :)
I've got a couple dev boxes with umpteen gigs of RAM, and still theres
massive disk access to program data, databases, etc.


-- 
Brent Jones
brent at servuhome.net



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