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    SubjectRe: [PATCH] mm: swap prefetch improvements
    Date
    On Tuesday 22 May 2007 20:25, Ingo Molnar wrote:
    > * Con Kolivas <kernel@kolivas.org> wrote:
    > > > > there was nothing else running on the system - so i suspect the
    > > > > swapin activity flagged 'itself' as some 'other' activity and
    > > > > stopped? The swapins happened in 4 bursts, separated by 5 seconds
    > > > > total idleness.
    > > >
    > > > I've noted burst swapins separated by some seconds of pause in my
    > > > desktop system too (with sp_tester and an idle gnome).
    > >
    > > That really is expected, as just about anything, including journal
    > > writeout, would be enough to put it back to sleep for 5 more seconds.
    >
    > note that nothing like that happened on my system - in the
    > swap-prefetch-off case there was _zero_ IO activity during the sleep
    > period.

    Ok, granted it's _very_ conservative. I really don't want to risk its presence
    being a burden on anything, and the iowait it induces probably makes it turn
    itself off for another PREFETCH_DELAY (5s). I really don't want to cross the
    line to where it is detrimental in any way. Not dropping out on a
    cond_resched and perhaps making the delay tunable should be enough to make it
    a little less "sleepy".

    --
    -ck
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