"Paul E. McKenney" <[EMAIL PROTECTED]> writes: > Turns out that compiler writers are a bit more aggressive about optimizing > than one might expect. This patch prevents a number of such optimizations > from messing up rcu_deference(). This is not merely a theoretical > problem, as evidenced by the rmb() in mce_log().
Don't think that's an improvement. rmb() at least is known to work reliable to prevent such reordering. Memory barriers are well documented in the gcc documentation. Who knows about volatile? The volatile semantics have been traditionally unclear and shakey. The C standard doesn't make much guarantees and i don't think gcc does either. If anything you might want to embedd rmb(); in a statement expression in rcu_deference instead. -Andi - 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/
