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    SubjectRe: [patch 0/3] mm: improve page aging fairness between zones/nodes
    On 19.07.2013 22:55, Johannes Weiner wrote:
    > The way the page allocator interacts with kswapd creates aging
    > imbalances, where the amount of time a userspace page gets in memory
    > under reclaim pressure is dependent on which zone, which node the
    > allocator took the page frame from.
    >
    > #1 fixes missed kswapd wakeups on NUMA systems, which lead to some
    > nodes falling behind for a full reclaim cycle relative to the other
    > nodes in the system
    >
    > #3 fixes an interaction where kswapd and a continuous stream of page
    > allocations keep the preferred zone of a task between the high and
    > low watermark (allocations succeed + kswapd does not go to sleep)
    > indefinitely, completely underutilizing the lower zones and
    > thrashing on the preferred zone
    >
    > These patches are the aging fairness part of the thrash-detection
    > based file LRU balancing. Andrea recommended to submit them
    > separately as they are bugfixes in their own right.
    >

    I have the patch applied and under testing. So far, so good. It looks
    like it could finally fix the bug that I was chasing few months ago
    (nicely described in your bullet #3). But, few more days of testing will
    be needed before I can reach a quality verdict.

    Good job!
    --
    Zlatko



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