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Commit ee7c29be authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

documentation: Update rcu_dereference.txt based on WG21 discussions 



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: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: default avatarMathieu Desnoyers <mathieu.desnoyers@efficios.com>
parent d956028e

Documentation/RCU/rcu_dereference.txt

+5 −0
Original line number Diff line number Diff line
@@ -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