echo 0 > /proc/sys/vm/swappiness triggers OOM killer under 2.6.14.

From: Rob Landley (rob_at_landley.net)
Date: 10/31/05

  • Next message: Adrian Bunk: "What is the history of CONFIG_EXT{2,3}_CHECK?"
    To: linux-kernel@vger.kernel.org
    Date:	Sun, 30 Oct 2005 18:09:04 -0600
    
    

    Under 2.6.14 (UML), I have a workload that runs with 64 megs ram and 256 megs
    swap space. It completes (albeit swapping like mad) with swappiness at the
    default 60, but if I set it to 0 the OOM killer kicks in and the script
    aborts.

    The workload is basically compiling gcc 4.0.2 with gcc 3.3.2. Now gcc a pig
    (hence the reason for feeding it 256 megs of swap space), but twiddling
    swappiness shouldn't make the difference between success and failure.

    Why does the OOM killer ever trigger when there are _any_ dirty pages queued
    up for DMA to an existing local block device? (Or when there is SWAP SPACE
    LEFT?) This is memory that will be freed in time, thus the system isn't
    guaranteed to hang yet. Don't we only need to trigger the OOM killer if the
    alternative is the system hanging?

    Rob

    P.S. Not only is this repeatable, but I have a script that I run that
    downloads the UML and gcc sources, builds UML, and tries to build GCC under
    it. I can put this up somewhere if anybody would like to try to reproduce
    this themselves...
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  • Next message: Adrian Bunk: "What is the history of CONFIG_EXT{2,3}_CHECK?"

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