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    SubjectRe: [PATCH] Documentation/preempt-locking.txt clarification
    Thomas Hood <jdthood@yahoo.co.uk> wrote:
    >
    > I have tried to clarify the text while at the same time
    > preserving the original meaning. Everything is pretty clear
    > now except for the last paragraph which I still find baffling.
    > I don't know what "a test to see if preemption is required" is
    > exactly and I don't understand when such a test is required.

    I guess it's saying that if you do this:

    local_irq_disable();
    lah_de_dah();
    local_irq_enable();

    then you should follow that by

    preempt_check_resched();

    just in case someone told this task to preempt itself while it had
    interrupts disabled.

    But I don't see why that's needed: if the preempt command came from another
    CPU then this CPU will take the cross-CPU interrupt as soon as interrupts
    are enabled. And the preempt command couldn't have come from _this_ CPU,
    because it had interrupts disabled.

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