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Commit 84483ea4 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: add shiny new debug assists to Documentation/RCU/checklist.txt 



Add a section describing PROVE_RCU, DEBUG_OBJECTS_RCU_HEAD, and
the __rcu sparse checking to the RCU checklist.

Suggested-by: default avatarDavid Miller <davem@davemloft.net>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: default avatarJosh Triplett <josh@joshtriplett.org>
parent 4b6a2872

Documentation/RCU/checklist.txt

+23 −0
Original line number Diff line number Diff line
@@ -365,3 +365,26 @@ over a rather long period of time, but improvements are always welcome! 
	and the compiler to freely reorder code into and out of RCU

	read-side critical sections.  It is the responsibility of the

	RCU update-side primitives to deal with this.



17.	Use CONFIG_PROVE_RCU, CONFIG_DEBUG_OBJECTS_RCU_HEAD, and

	the __rcu sparse checks to validate your RCU code.  These

	can help find problems as follows:



	CONFIG_PROVE_RCU: check that accesses to RCU-protected data

		structures are carried out under the proper RCU

		read-side critical section, while holding the right

		combination of locks, or whatever other conditions

		are appropriate.



	CONFIG_DEBUG_OBJECTS_RCU_HEAD: check that you don't pass the

		same object to call_rcu() (or friends) before an RCU

		grace period has elapsed since the last time that you

		passed that same object to call_rcu() (or friends).



	__rcu sparse checks: tag the pointer to the RCU-protected data

		structure with __rcu, and sparse will warn you if you

		access that pointer without the services of one of the

		variants of rcu_dereference().



	These debugging aids can help you find problems that are

	otherwise extremely difficult to spot.