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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2010-06-16 16:48:13 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2010-08-19 17:18:01 -0700
commit84483ea42cd4f2781d6e97a83ab3ebd0ff19fb10 (patch)
treec79e79331ab451218aac8c99b74797291beaf841 /Documentation/RCU/checklist.txt
parent4b6a2872a2a00042ee50024822ab706e5456aad8 (diff)
downloadlinux-linaro-stable-84483ea42cd4f2781d6e97a83ab3ebd0ff19fb10.tar.gz
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 <davem@davemloft.net> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'Documentation/RCU/checklist.txt')
-rw-r--r--Documentation/RCU/checklist.txt23
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diff --git a/Documentation/RCU/checklist.txt b/Documentation/RCU/checklist.txt
index 790d1a812376..c7c6788956f4 100644
--- a/Documentation/RCU/checklist.txt
+++ b/Documentation/RCU/checklist.txt
@@ -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.