----- Original Message ----- > From: "Paul E. McKenney" <[email protected]> > > This commit provides another caveat for the care and feeding of pointers > returned by rcu_dereference() that was pointed out in discussions within > the C++ standards committee. > > Signed-off-by: Paul E. McKenney <[email protected]>
Reviewed-by: Mathieu Desnoyers <[email protected]> BTW, reading through rcu_dereference.txt, I found a nit: operatiors -> operators Very interesting reading :) Thanks! Mathieu > --- > Documentation/RCU/rcu_dereference.txt | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/Documentation/RCU/rcu_dereference.txt > b/Documentation/RCU/rcu_dereference.txt > index ceb05da5a5ac..2d05c9241a33 100644 > --- a/Documentation/RCU/rcu_dereference.txt > +++ b/Documentation/RCU/rcu_dereference.txt > @@ -193,6 +193,11 @@ o Be very careful about comparing pointers > obtained from > pointer. Note that the volatile cast in rcu_dereference() > will normally prevent the compiler from knowing too much. > > + However, please note that if the compiler knows that the > + pointer takes on only one of two values, a not-equal > + comparison will provide exactly the information that the > + compiler needs to deduce the value of the pointer. > + > o Disable any value-speculation optimizations that your compiler > might provide, especially if you are making use of feedback-based > optimizations that take data collected from prior runs. Such > -- > 1.8.1.5 > > -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com -- 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/
