|author||Paul E. McKenney <email@example.com>||2010-06-16 16:48:13 -0700|
|committer||Paul E. McKenney <firstname.lastname@example.org>||2010-08-19 17:18:01 -0700|
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: David Miller <email@example.com> Signed-off-by: Paul E. McKenney <firstname.lastname@example.org> Reviewed-by: Josh Triplett <email@example.com>
1 files changed, 23 insertions, 0 deletions
diff --git a/Documentation/RCU/checklist.txt b/Documentation/RCU/checklist.txt
index 790d1a812376..c7c6788956f4 100644
@@ -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.