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authorPaul E. McKenney <paul.mckenney@linaro.org>2012-10-19 12:49:17 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2013-01-28 22:06:21 -0800
commit6bfc09e2327dfbffc312004c16188dbf8dfb0297 (patch)
treef36ac34ec671ea5eaa926ebabba8486bbda9c175 /kernel/rcu.h
parent1b0048a44c502c5ab850203e6e0a6498d7d8676d (diff)
downloadlwn-6bfc09e2327dfbffc312004c16188dbf8dfb0297.tar.gz
lwn-6bfc09e2327dfbffc312004c16188dbf8dfb0297.zip
rcu: Provide RCU CPU stall warnings for tiny RCU
Tiny RCU has historically omitted RCU CPU stall warnings in order to reduce memory requirements, however, lack of these warnings caused Thomas Gleixner some debugging pain recently. Therefore, this commit adds RCU CPU stall warnings to tiny RCU if RCU_TRACE=y. This keeps the memory footprint small, while still enabling CPU stall warnings in kernels built to enable them. Updated to include Josh Triplett's suggested use of RCU_STALL_COMMON config variable to simplify #if expressions. Reported-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'kernel/rcu.h')
-rw-r--r--kernel/rcu.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/rcu.h b/kernel/rcu.h
index 20dfba576c2b..7f8e7590e3e5 100644
--- a/kernel/rcu.h
+++ b/kernel/rcu.h
@@ -111,4 +111,11 @@ static inline bool __rcu_reclaim(char *rn, struct rcu_head *head)
extern int rcu_expedited;
+#ifdef CONFIG_RCU_STALL_COMMON
+
+extern int rcu_cpu_stall_suppress;
+int rcu_jiffies_till_stall_check(void);
+
+#endif /* #ifdef CONFIG_RCU_STALL_COMMON */
+
#endif /* __LINUX_RCU_H */