On Thu, Apr 13, 2017 at 11:18:32AM +0200, Peter Zijlstra wrote: > On Wed, Apr 12, 2017 at 09:55:43AM -0700, Paul E. McKenney wrote: > > However, a little future-proofing is a good thing, > > especially given that smp_mb__before_atomic() is only required to > > provide acquire semantics rather than full ordering. This commit > > therefore adds smp_mb__after_atomic() after the atomic_long_inc() > > in sync_exp_work_done(). > > Oh!? As far as I'm away the smp_mb__{before,after}_atomic() really must > provide full MB, no confusion about that. > > We have other primitives for acquire/release.
Hmmm... Rechecking atomic_ops.txt, it does appear that you are quite correct. Adding Will and Dmitry on CC, but dropping this patch for now. Thanx, Paul