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>
diff --git a/lib/ratelimit.c b/lib/ratelimit.c
index 485e304..3513667 100644
--- a/lib/ratelimit.c
+++ b/lib/ratelimit.c
@@ -3,6 +3,9 @@
*
* Isolated from kernel/printk.c by Dave Young <hidave.darkstar@gmail.com>
*
+ * 2008-05-01 rewrite the function and use a ratelimit_state data struct as
+ * parameter. Now every user can use their own standalone ratelimit_state.
+ *
* This file is released under the GPLv2.
*
*/
@@ -11,41 +14,43 @@
#include <linux/jiffies.h>
#include <linux/module.h>
+static DEFINE_SPINLOCK(ratelimit_lock);
+static unsigned long flags;
+
/*
* __ratelimit - rate limiting
- * @ratelimit_jiffies: minimum time in jiffies between two callbacks
- * @ratelimit_burst: number of callbacks we do before ratelimiting
+ * @rs: ratelimit_state data
*
- * This enforces a rate limit: not more than @ratelimit_burst callbacks
- * in every ratelimit_jiffies
+ * This enforces a rate limit: not more than @rs->ratelimit_burst callbacks
+ * in every @rs->ratelimit_jiffies
*/
-int __ratelimit(int ratelimit_jiffies, int ratelimit_burst)
+int __ratelimit(struct ratelimit_state *rs)
{
- static DEFINE_SPINLOCK(ratelimit_lock);
- static unsigned toks = 10 * 5 * HZ;
- static unsigned long last_msg;
- static int missed;
- unsigned long flags;
- unsigned long now = jiffies;
+ if (!rs->interval)
+ return 1;
spin_lock_irqsave(&ratelimit_lock, flags);
- toks += now - last_msg;
- last_msg = now;
- if (toks > (ratelimit_burst * ratelimit_jiffies))
- toks = ratelimit_burst * ratelimit_jiffies;
- if (toks >= ratelimit_jiffies) {
- int lost = missed;
+ if (!rs->begin)
+ rs->begin = jiffies;
- missed = 0;
- toks -= ratelimit_jiffies;
- spin_unlock_irqrestore(&ratelimit_lock, flags);
- if (lost)
- printk(KERN_WARNING "%s: %d messages suppressed\n",
- __func__, lost);
- return 1;
+ if (time_is_before_jiffies(rs->begin + rs->interval)) {
+ if (rs->missed)
+ printk(KERN_WARNING "%s: %d callbacks suppressed\n",
+ __func__, rs->missed);
+ rs->begin = 0;
+ rs->printed = 0;
+ rs->missed = 0;
}
- missed++;
+ if (rs->burst && rs->burst > rs->printed)
+ goto print;
+
+ rs->missed++;
spin_unlock_irqrestore(&ratelimit_lock, flags);
return 0;
+
+print:
+ rs->printed++;
+ spin_unlock_irqrestore(&ratelimit_lock, flags);
+ return 1;
}
EXPORT_SYMBOL(__ratelimit);