> So is > > while (__raw_spin_is_locked(&v)); > > supposed to work? Or should that be > > while (__raw_spin_is_locked(&v)) > cpu_relax(); > > as well and all the volatiles can/should go away?
cpu_relax() is a really good idea in every spinloop on hyper-threaded cores. It lets the h/w know that we aren't doing anything useful here, so resources and power can be diverted to other threads sharing the core. Avoiding the need for volatile or other compiler optimizer defeating tricks is a side benefit. -Tony - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
