On Tue, 15 Oct 2013 22:18:48 +0200 Frederic Weisbecker <[email protected]> wrote:
> How about just updating __warned without a cmpxchg. It's not that critical > if the update is not seen immediately to other CPUs. OTOH it's critical > that's it is visible immediately to the current CPU Well, I didn't use cmpxchg() I used xchg() which is actually quite faster. > > I mean some warrning can be hard to reproduce and happen to some users > while staying for several kernel releases. If it's repetitive, the xchg > might impact the performance. But do we care about that? A WARN_ON() means the kernel (or hardware) is buggy. It should be fixed. But Andrew's ONCE() request is something we would want to avoid the xchg() every time. > > I may be overly paranoid, but I think barrier() (so that at least > we don't recurse locally) alone would be better. Heh, Boris is giving me the same argument on IRC ;-) -- Steve -- 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/
