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    SubjectVery bad behavior of kswapd
    Try this (my example I've 2GB of ram)

    turn all your swap off

    dd about 15% of the size of your RAM:
    dd if=/dev/zero of=/local/test count=300 bs=1000000

    Run this program with SIZE about 95% of your RAM:

    #include <stdlib.h>
    #include <unistd.h>
    #include <assert.h>

    #define SIZE (1900 * 1024 * 1024)
    int main()
    {
    int i;
    char *p = malloc(SIZE);
    assert (p != NULL);
    for (i = 0; i < SIZE; i++)
    p[i] = 1;
    printf ("done %p\n", p);

    while (1)
    {
    sleep (60);
    }
    return 0;
    }


    Watch top: when this program needs the memory that kswapd keep in cache they go
    both at 100% cpu (on SMP) but still the size of the program only grows at about
    100KB/s, why is kswapd releasing it so slowly and taking so much CPU ?

    Laurent Chavet

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