Nick Piggin wrote on Thursday, March 30, 2006 11:35 PM > > Whoever designed the smp_mb_before/after_* clearly understand the > > difference between a bidirectional smp_mb() and a one-way memory > > ordering. If smp_mb_before/after are equivalent to smp_mb, what's > > the point of introducing another interface? > > > > They are not. They provide equivalent barrier when performed > before/after a clear_bit, there is a big difference. Just to give another blunt brutal example, what is said here is equivalent to say kernel requires: <end of critical section> smp_mb_before_spin_unlock spin_unlock Because it is undesirable to have spin_unlock to leak into the critical Section and allow critical section to leak after spin_unlock. This is just plain brain dead. - : send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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