On Thu, Jan 08, 2015 at 10:41:02AM +0100, Peter Zijlstra wrote: > On Wed, Jan 07, 2015 at 09:32:20AM -0800, Paul E. McKenney wrote: > > From: "Paul E. McKenney" <paul...@linux.vnet.ibm.com> > > > > This commit prevents random compiler optimizations by applying > > ACCESS_ONCE() to lockless accesses. > > > > Signed-off-by: Paul E. McKenney <paul...@linux.vnet.ibm.com> > > --- > > kernel/rcu/tree_plugin.h | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h > > index 3ec85cb5d544..d59913ef8360 100644 > > --- a/kernel/rcu/tree_plugin.h > > +++ b/kernel/rcu/tree_plugin.h > > @@ -1127,7 +1127,8 @@ static int rcu_boost(struct rcu_node *rnp) > > struct task_struct *t; > > struct list_head *tb; > > > > - if (rnp->exp_tasks == NULL && rnp->boost_tasks == NULL) > > + if (ACCESS_ONCE(rnp->exp_tasks) == NULL && > > + ACCESS_ONCE(rnp->boost_tasks) == NULL) > > return 0; /* Nothing left to boost. */ > > Didn't we just obsolete ACCESS_ONCE with that {READ,WRITE}_ONCE stuff?
Indeed we did! But that was after I did this commit back on October 29th. I am planning a bulk change to READ_ONCE() and ASSIGN_ONCE() either as the last patch for 3.20 or as the first one for 3.21. Probably as the first for 3.21 to minimize rebasing hassles with any needed 3.20 fixes. Thanx, Paul -- 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/