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    SubjectRe: [RFC PATCH 0/6] Convert all tasklets to workqueues

    * Daniel Walker <> wrote:

    > > - tasklets have certain fairness limitations. (they are executed in
    > > softirq context and thus preempt everything, even if there is
    > > some potentially more important, high-priority task waiting to be
    > > executed.)
    > Since -rt has been executing tasklets in process context for a long
    > time, I'm not sure this change would cause to many regressions.
    > However, it seems like implicit dependencies on "tasklets preempt
    > everything" might crop up. The other issue is if they don't "preempt
    > everything" (most of the time), what default priority do we give them
    > (all of the time)? [...]

    there is no such guarantee at all (of 'instant preemption'), even with
    current, softirq-based tasklets. A tasklet might be 'stolen' by another
    CPU. It might be delayed to the next timer tick (or other softirq
    execution). Or it might be delayed into a ksoftirqd context, which
    currently runs at nice +19. So your worry of implicit execution
    dependencies is unfounded, because, if they existed, they would be bad
    (and triggerable) bugs today too.

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      Last update: 2007-06-23 00:19    [W:0.021 / U:147.116 seconds]
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