On Tue, 2015-04-28 at 18:43 +0200, Peter Zijlstra wrote: > Well, if you can 'guarantee' the cmpxchg will not fail, you can then > rely on the fact that cmpxchg implies a full barrier, which would > obviate the need for the wmb.
Yes, assuming it implies barriers on both sides. And we could obviously remove the need for pairing. With wake_q being local to wq_sleep() I cannot see duplicate tasks trying to add themselves in the list. Failed cmpxchg should only occur when users start misusing the wake_q. Manfred, do you have any objections to this? Perhaps I've missed the real purpose of the barriers. Thanks, Davidlohr -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
