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    Subject[PATCH] 0/2 swap token tuning
    A while ago the swap token (aka token based thrashing control)
    mechanism was introduced into Linux. This code improves performance
    under heavy VM loads, but can reduce performance under very light
    VM loads.

    The cause turns out to be me overlooking something in the original
    token based thrashing control paper: the swap token is only supposed
    to be enforced while the task holding the swap token is paging data
    in, not while the task is running (and referencing its working set).

    The temporary solution in Linux was to disable the swap token code
    and have users turn it on again via /proc. The following patch
    instead approximates the "only enforce the swap token if the task
    holding it is swapping something in" idea. This should make sure
    the swap token is effectively disabled when the VM load is low.

    I have not benchmarked these patches yet; instead, I'm posting
    them before the weekend is over, hoping to catch a bit of test
    time from others while my own tests are being run ;)

    The Theory of Escalating Commitment: "The cost of continuing mistakes is
    borne by others, while the cost of admitting mistakes is borne by yourself."
    -- Joseph Stiglitz, Nobel Laureate in Economics
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      Last update: 2005-06-27 00:39    [W:0.021 / U:91.208 seconds]
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