[PATCH 1/3] Add ratelimited printk for different alert levels

[raghu.prabhu13 at gmail.com]

From: Raghavendra D Prabhu <rprabhu at wnohang.net>

Ratelimited printk will be useful in printing xfs messages which are otherwise
not required to be printed always due to their high rate (to prevent kernel ring
buffer from overflowing), while at the same time required to be printed.

Signed-off-by: Raghavendra D Prabhu <rprabhu at wnohang.net>
---
 fs/xfs/xfs_message.h | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/fs/xfs/xfs_message.h b/fs/xfs/xfs_message.h
index 56dc0c1..87999a5 100644
--- a/fs/xfs/xfs_message.h
+++ b/fs/xfs/xfs_message.h
@@ -1,6 +1,8 @@
 #ifndef __XFS_MESSAGE_H
 #define __XFS_MESSAGE_H 1
 
+#include <linux/ratelimit.h>
+
 struct xfs_mount;
 
 extern __printf(2, 3)
@@ -30,6 +32,32 @@ void xfs_debug(const struct xfs_mount *mp, const char *fmt, ...)
 }
 #endif
 
+#define xfs_printk_ratelimited(xfs_printk, dev, fmt, ...)		\
+do {									\
+	static DEFINE_RATELIMIT_STATE(_rs,				\
+				      DEFAULT_RATELIMIT_INTERVAL,	\
+				      DEFAULT_RATELIMIT_BURST);		\
+	if (__ratelimit(&_rs))						\
+		xfs_printk(dev, fmt, ##__VA_ARGS__);			\
+} while (0)
+
+#define xfs_emerg_ratelimited(dev, fmt, ...)				\
+	xfs_printk_ratelimited(xfs_emerg, dev, fmt, ##__VA_ARGS__)
+#define xfs_alert_ratelimited(dev, fmt, ...)				\
+	xfs_printk_ratelimited(xfs_alert, dev, fmt, ##__VA_ARGS__)
+#define xfs_crit_ratelimited(dev, fmt, ...)				\
+	xfs_printk_ratelimited(xfs_crit, dev, fmt, ##__VA_ARGS__)
+#define xfs_err_ratelimited(dev, fmt, ...)				\
+	xfs_printk_ratelimited(xfs_err, dev, fmt, ##__VA_ARGS__)
+#define xfs_warn_ratelimited(dev, fmt, ...)				\
+	xfs_printk_ratelimited(xfs_warn, dev, fmt, ##__VA_ARGS__)
+#define xfs_notice_ratelimited(dev, fmt, ...)				\
+	xfs_printk_ratelimited(xfs_notice, dev, fmt, ##__VA_ARGS__)
+#define xfs_info_ratelimited(dev, fmt, ...)				\
+	xfs_printk_ratelimited(xfs_info, dev, fmt, ##__VA_ARGS__)
+#define xfs_dbg_ratelimited(dev, fmt, ...)				\
+	xfs_printk_ratelimited(xfs_dbg, dev, fmt, ##__VA_ARGS__)
+
 extern void assfail(char *expr, char *f, int l);
 
 extern void xfs_hex_dump(void *p, int length);
-- 
1.7.12