On Wed, Jun 01, 2016 at 06:22:55PM +0200, Peter Zijlstra wrote: > On Wed, Jun 01, 2016 at 09:52:14PM +0800, Boqun Feng wrote: > > On Tue, May 31, 2016 at 11:41:37AM +0200, Peter Zijlstra wrote: > > > > @@ -292,7 +282,7 @@ static void sem_wait_array(struct sem_ar > > > sem = sma->sem_base + i; > > > spin_unlock_wait(&sem->lock); > > > } > > > - ipc_smp_acquire__after_spin_is_unlocked(); > > > + smp_acquire__after_ctrl_dep(); > > > > I wonder whether we can kill this barrier after updating > > spin_unlock_wait() to ACQUIRE? > > See patch 5 doing that :-) Oops, right ;-) Regards, Boqun