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    SubjectRe: [ANNOUNCE] Linux 2.6 Real Time Kernel
    Date
    Sven-Thorsten Dietrich <sdietrich@mvista.com> writes:

    > +#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT)
    > +/*
    > + * This could be a long-held lock. If another CPU holds it for a long time,
    > + * and that CPU is not asked to reschedule then *this* CPU will spin on the
    > + * lock for a long time, even if *this* CPU is asked to reschedule.
    > + *
    > + * So what we do here, in the slow (contended) path is to spin on the lock by
    > + * hand while permitting preemption.
    > + *
    > + * Called inside preempt_disable().
    > + */
    > +
    > +/* these functions are only called from inside spin_lock
    > + * and old_write_lock therefore under spinlock substitution
    > + * they will only be passed old spinlocks or old rwlocks as parameter
    > + * there are no issues with modified mutex behavior here. */
    > +
    > +#endif /* defined(CONFIG_SMP) && defined(CONFIG_PREEMPT) */

    May I inquire as to the purpose of placing a couple of comments under
    an #ifdef?

    --
    Måns Rullgård
    mru@mru.ath.cx

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