Re: Serious problem with memory management?

From: Ober0n (ober0n_at_op.pl)
Date: 02/12/04

  • Next message: Robert Nichols: "Re: Get uptime with /proc not mounted" 
    Date: Thu, 12 Feb 2004 18:19:21 +0100

    Jens.Toerring@physik.fu-berlin.de wrote:

    > First of all, your system does not (or at least should not) hang, but
    > it gets probably extremely slow because you run out of RAM and it starts
    > swapping a lot. That can feel like it hangs but it doesn't.

    The problem is, it looks like hang. System is swapping a lot, but after
    some time it _stops_. HDD diode stops blinking too (after some time, of
    course). I made my tests with swap disabled, with the same effect.
    System is completely unusable, so for end-user it's hanged.
    I found on google that it can take several hours to recover
    system from OOM condition...

    > Try to write a 0 to y
    y, i.e. do
    >
    > echo 0 > /proc/sys/vm/overcommit_memory

    # cat /proc/sys/vm/overcommit_memory
    0

    As you can see, it's already zero. I'll play with 1, but later.
    Thanks for pointing this. I didn't know about this feature.

    > Another thing you could play around with if you want malloc() to
    > return NULL is setting a limit for the maximum amount of memory
    > your processes are allowed to use, using ulimit.

    It's my personal desktop station shared with second user (x-terminal).
    Is it possible to limit maximum amount of memory for ALL non-root users
    and sessions? For ex. I have 768MB of ram and I want to make only 750MB
    available for normal user programs, but without any limits for single
    program of each user (so users can eat all 750MB). This makes rest of RAM
    reserved and not accessible for normal users. I think it's good idea to
    reserve some memory to make system recovery from OOM possible. Can I do it
    using pam limits? And what do you think about this solution?

    > Regards, Jens

    Thanks a lot, Ober0n

    Again, sorry for poor english.

  • Next message: Robert Nichols: "Re: Get uptime with /proc not mounted"

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