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    SubjectRe: scheduling problem?

    On Fri, 17 Dec 1999, Andrea Arcangeli wrote:

    > On Thu, 16 Dec 1999, Jamie Lokier wrote:
    >
    > > asm volatile("sti ; hlt" : : : "memory");
    > ^^^^^^^^^
    >
    > The wakeup can still happen between sti and hlt so it doesn't fix the
    > irq race condition.
    >
    The Intel Assembly Language Reference Manual states that the sti
    instruction sets the interrupt flag to 1 and the CPU then responds
    to external interrupts after executing the *next* instruction if the
    next instruction allows the interrupt to remain enabled. So the
    wakeup can only happen _after_ the hlt which is the desired effect.

    I have implemented the above patch and tested overnight with no
    more problems due to the idle task.

    Wm


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