Documentation/RCU/whatisRCU.rst

103 b.	Wait for all previous readers to complete their RCU read-side
166 	reclaimer that the reader is entering an RCU read-side critical
167 	section.  It is illegal to block while in an RCU read-side
169 	can preempt RCU read-side critical sections.  Any RCU-protected
170 	data structure accessed during an RCU read-side critical section
180 	reclaimer that the reader is exiting an RCU read-side critical
181 	section.  Note that RCU read-side critical sections may be nested
190 	all pre-existing RCU read-side critical sections on all CPUs
192 	necessarily wait for any subsequent RCU read-side critical
206 	read-side critical sections to complete, not necessarily for
210 	**immediately** after the last pre-existing RCU read-side critical
224 	argument which are invoked after all ongoing RCU read-side
227 	or where update-side performance is critically important.
297 	only within the enclosing RCU read-side critical section [1]_.
308 	Holding a reference from one RCU read-side critical section
324 	of an RCU read-side critical section as long as the usage is
325 	protected by locks acquired by the update-side code.  This variant
337 	update-side code as well as by RCU readers, then an additional
341 	invoked outside of an RCU read-side critical section and without
379 above shows the most common one. On the updater side, the rcu_assign_pointer(),
381 flavors. However for protection (on the reader side), the primitives used vary
481 	read-side critical sections.
483 -	Within an RCU read-side critical section, use rcu_dereference()
498 	RCU read-side critical sections that might be referencing that
588 	read-side critical sections that might be referencing that
635 one read-side critical section to another.  It also assumes recursive
682 that once synchronize_rcu() exits, all RCU read-side critical sections
730 read-side overhead is precisely zero, at least on non-Alpha CPUs.
743 Remember that it is illegal to block while in an RCU read-side critical
745 that it must have completed all preceding RCU read-side critical sections.
747 RCU read-side critical sections will have completed.
751 that there are no RCU read-side critical sections holding a reference
757 		Give an example where Classic RCU's read-side
765 		If it is illegal to block in an RCU read-side
831 Or, for those who prefer a side-by-side listing::
882 Either way, the differences are quite small.  Read-side locking moves
883 to rcu_read_lock() and rcu_read_unlock, update-side locking moves from
887 However, there is one potential catch: the read-side and update-side
1168 g.	Do you need read-side critical sections that are respected even
1218 		consider task A in an RCU read-side critical section
1222 		read_acquire rcu_gp_mutex.  Task A's RCU read-side
1227 		approach where tasks in RCU read-side critical sections
1233 		Give an example where Classic RCU's read-side
1262 		If it is illegal to block in an RCU read-side
1269 		read-side critical sections.  It also permits
1270 		spinlocks blocking while in RCU read-side critical