+
+---------------------------
+
+What: RCU API moves to EXPORT_SYMBOL_GPL
+When: April 2006
+Files: include/linux/rcupdate.h, kernel/rcupdate.c
+Why: Outside of Linux, the only implementations of anything even
+ vaguely resembling RCU that I am aware of are in DYNIX/ptx,
+ VM/XA, Tornado, and K42. I do not expect anyone to port binary
+ drivers or kernel modules from any of these, since the first two
+ are owned by IBM and the last two are open-source research OSes.
+ So these will move to GPL after a grace period to allow
+ people, who might be using implementations that I am not aware
+ of, to adjust to this upcoming change.
+Who: Paul E. McKenney <paulmck@us.ibm.com>