printk ratelimiting rewrite

All ratelimit user use same jiffies and burst params, so some messages
(callbacks) will be lost.

For example:
a call printk_ratelimit(5 * HZ, 1)
b call printk_ratelimit(5 * HZ, 1) before the 5*HZ timeout of a, then b will
will be supressed.

- rewrite __ratelimit, and use a ratelimit_state as parameter.  Thanks for
  hints from andrew.

- Add WARN_ON_RATELIMIT, update rcupreempt.h

- remove __printk_ratelimit

- use __ratelimit in net_ratelimit

Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Dave Young <hidave.darkstar@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

5 files changed, 40 insertions, 10 deletions

diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index a346e74..a3f738c 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -97,6 +97,9 @@ extern void warn_slowpath(const char *file, const int line,
 	unlikely(__ret_warn_once);				\
 })
 
+#define WARN_ON_RATELIMIT(condition, state)			\
+		WARN_ON((condition) && __ratelimit(state))
+
 #ifdef CONFIG_SMP
 # define WARN_ON_SMP(x)			WARN_ON(x)
 #else
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 5c4b125..fdbbf72 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -15,6 +15,7 @@
 #include <linux/bitops.h>
 #include <linux/log2.h>
 #include <linux/typecheck.h>
+#include <linux/ratelimit.h>
 #include <asm/byteorder.h>
 #include <asm/bug.h>
 
@@ -189,11 +190,8 @@ asmlinkage int vprintk(const char *fmt, va_list args)
 asmlinkage int printk(const char * fmt, ...)
 	__attribute__ ((format (printf, 1, 2))) __cold;
 
-extern int printk_ratelimit_jiffies;
-extern int printk_ratelimit_burst;
+extern struct ratelimit_state printk_ratelimit_state;
 extern int printk_ratelimit(void);
-extern int __ratelimit(int ratelimit_jiffies, int ratelimit_burst);
-extern int __printk_ratelimit(int ratelimit_jiffies, int ratelimit_burst);
 extern bool printk_timed_ratelimit(unsigned long *caller_jiffies,
 				   unsigned int interval_msec);
 #else
@@ -204,8 +202,6 @@ static inline int printk(const char *s, ...)
 	__attribute__ ((format (printf, 1, 2)));
 static inline int __cold printk(const char *s, ...) { return 0; }
 static inline int printk_ratelimit(void) { return 0; }
-static inline int __printk_ratelimit(int ratelimit_jiffies, \
-				     int ratelimit_burst) { return 0; }
 static inline bool printk_timed_ratelimit(unsigned long *caller_jiffies, \
 					  unsigned int interval_msec)	\
 		{ return false; }
diff --git a/include/linux/net.h b/include/linux/net.h
index 2f999fb..4a9a30f 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -351,8 +351,7 @@ static const struct proto_ops name##_ops = {			\
 
 #ifdef CONFIG_SYSCTL
 #include <linux/sysctl.h>
-extern int net_msg_cost;
-extern int net_msg_burst;
+extern struct ratelimit_state net_ratelimit_state;
 #endif
 
 #endif /* __KERNEL__ */
diff --git a/include/linux/ratelimit.h b/include/linux/ratelimit.h
new file mode 100644
index 0000000..18a5b9b
--- /dev/null
+++ b/include/linux/ratelimit.h
@@ -0,0 +1,27 @@
+#ifndef _LINUX_RATELIMIT_H
+#define _LINUX_RATELIMIT_H
+#include <linux/param.h>
+
+#define DEFAULT_RATELIMIT_INTERVAL (5 * HZ)
+#define DEFAULT_RATELIMIT_BURST 10
+
+struct ratelimit_state {
+	int interval;
+	int burst;
+	int printed;
+	int missed;
+	unsigned long begin;
+};
+
+#define DEFINE_RATELIMIT_STATE(name, interval, burst)		\
+		struct ratelimit_state name = {interval, burst,}
+
+extern int __ratelimit(struct ratelimit_state *rs);
+
+static inline int ratelimit(void)
+{
+	static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL,
+					DEFAULT_RATELIMIT_BURST);
+	return __ratelimit(&rs);
+}
+#endif
diff --git a/include/linux/rcupreempt.h b/include/linux/rcupreempt.h
index f04b64e..0967f03 100644
--- a/include/linux/rcupreempt.h
+++ b/include/linux/rcupreempt.h
@@ -115,16 +115,21 @@ DECLARE_PER_CPU(struct rcu_dyntick_sched, rcu_dyntick_sched);
 
 static inline void rcu_enter_nohz(void)
 {
+	static DEFINE_RATELIMIT_STATE(rs, 10 * HZ, 1);
+
 	smp_mb(); /* CPUs seeing ++ must see prior RCU read-side crit sects */
 	__get_cpu_var(rcu_dyntick_sched).dynticks++;
-	WARN_ON(__get_cpu_var(rcu_dyntick_sched).dynticks & 0x1);
+	WARN_ON_RATELIMIT(__get_cpu_var(rcu_dyntick_sched).dynticks & 0x1, &rs);
 }
 
 static inline void rcu_exit_nohz(void)
 {
+	static DEFINE_RATELIMIT_STATE(rs, 10 * HZ, 1);
+
 	smp_mb(); /* CPUs seeing ++ must see later RCU read-side crit sects */
 	__get_cpu_var(rcu_dyntick_sched).dynticks++;
-	WARN_ON(!(__get_cpu_var(rcu_dyntick_sched).dynticks & 0x1));
+	WARN_ON_RATELIMIT(!(__get_cpu_var(rcu_dyntick_sched).dynticks & 0x1),
+				&rs);
 }
 
 #else /* CONFIG_NO_HZ */