Nick Piggin wrote on Thursday, March 30, 2006 6:53 PM > >>smp_mb__before_clear_bit() > >>clear_bit(...)( > > > > Sorry, you totally lost me. It could me I'm extremely slow today. For > > option (1), on ia64, clear_bit has release semantic already. The comb > > of __before_clear_bit + clear_bit provides the required ordering. Did > > I miss something? By the way, we are talking about detail implementation > > on one specific architecture. Not some generic concept that clear_bit > > has no ordering stuff in there. > > > > The memory ordering that above combination should produce is a > Linux style smp_mb before the clear_bit. Not a release. 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? - Ken - : 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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