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    SubjectRe: Slow, persistent memory leak in 2.6.20
    On 8/26/07, Jan Engelhardt <> wrote:
    > On Aug 26 2007 11:51, Fred Tyler wrote:
    > >On 8/26/07, Fred Tyler <> wrote:
    > >> I think I've come across a memory leak in 2.6.20. I've upgraded to the
    > >> latest, but it didn't seem to help.
    > >
    > >Sorry to keep replying to my own post, but further investigation
    > >suggests that the memory losses may be occurring at times of heavy
    > >filesystem access. The machines in question run rsyncs of hundreds of
    > >thousands of files every few hours, and I'm starting to think that the
    > >memory loss occurs during these times. I don't know how I'd go about
    > >proving this though...
    > Please rule out filesystem caches by issuing
    > sync;
    > echo 3 >/proc/sys/vm/drop_caches;

    (Sorry if this goes to the list twice... Mailer problems.)

    Ok, I did this on a non-production machine that has only been up for a
    few hours, and here's what happened:

    ======== Before =========

    $ free -m
    total used free shared buffers cached
    Mem: 878 824 54 0 111 422
    -/+ buffers/cache: 290 587
    Swap: 63 0 63

    ======== After ========

    root@b0$ free -m
    total used free shared buffers cached
    Mem: 878 47 830 0 6 4
    -/+ buffers/cache: 36 841
    Swap: 63 0 63


    So, I guess it worked? (I don't know what was supposed to happen, but
    memory usage dropped significantly when I did this.)

    However, I'm not sure this staging machine has been up long enough or
    doing enough to exhibit the problem. I can try this on my production
    servers (the ones I provided graphs for) late tonight, but how safe is
    running this command? Does it permanently disable file caching? Do I
    need to reset it afterwards? If I stop all services (databases,
    logging, etc) first, am I protected against data loss?
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      Last update: 2007-08-26 18:29    [W:0.029 / U:3.312 seconds]
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