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    SubjectRE: [patch] scheduler bugfix, SMP, 2.4.0-test7

    On Mon, 28 Aug 2000, Dimitris Michailidis wrote:

    > > the attached sched-2.4.0-test7-C1 patch fixes a 'missed wakeup'
    > > SMP-scheduler bug.
    >
    > +running_again:
    > + if (prev == idle_task(smp_processor_id()))
    > + goto out_unlock;
    >
    > Why don't you move the test for the idle task to the beginning of the
    > function so we don't need to take the run queue lock if prev is idle? There
    > is nothing to be done for idle tasks, we don't even need to set ->has_cpu.

    for performance reasons. The whole running_again path is extremely rare
    (because the window for a re-wakeup is small), so i moved all checks into
    the slow path and made the common code fall-through.

    Ingo

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