Commit | Line | Data |
---|---|---|
5f97a5a8 DY |
1 | /* |
2 | * ratelimit.c - Do something with rate limit. | |
3 | * | |
4 | * Isolated from kernel/printk.c by Dave Young <hidave.darkstar@gmail.com> | |
5 | * | |
6 | * This file is released under the GPLv2. | |
7 | * | |
8 | */ | |
9 | ||
10 | #include <linux/kernel.h> | |
11 | #include <linux/jiffies.h> | |
12 | #include <linux/module.h> | |
13 | ||
14 | /* | |
15 | * __ratelimit - rate limiting | |
16 | * @ratelimit_jiffies: minimum time in jiffies between two callbacks | |
17 | * @ratelimit_burst: number of callbacks we do before ratelimiting | |
18 | * | |
19 | * This enforces a rate limit: not more than @ratelimit_burst callbacks | |
20 | * in every ratelimit_jiffies | |
21 | */ | |
22 | int __ratelimit(int ratelimit_jiffies, int ratelimit_burst) | |
23 | { | |
24 | static DEFINE_SPINLOCK(ratelimit_lock); | |
25 | static unsigned toks = 10 * 5 * HZ; | |
26 | static unsigned long last_msg; | |
27 | static int missed; | |
28 | unsigned long flags; | |
29 | unsigned long now = jiffies; | |
30 | ||
31 | spin_lock_irqsave(&ratelimit_lock, flags); | |
32 | toks += now - last_msg; | |
33 | last_msg = now; | |
34 | if (toks > (ratelimit_burst * ratelimit_jiffies)) | |
35 | toks = ratelimit_burst * ratelimit_jiffies; | |
36 | if (toks >= ratelimit_jiffies) { | |
37 | int lost = missed; | |
38 | ||
39 | missed = 0; | |
40 | toks -= ratelimit_jiffies; | |
41 | spin_unlock_irqrestore(&ratelimit_lock, flags); | |
42 | if (lost) | |
43 | printk(KERN_WARNING "%s: %d messages suppressed\n", | |
44 | __func__, lost); | |
45 | return 1; | |
46 | } | |
47 | missed++; | |
48 | spin_unlock_irqrestore(&ratelimit_lock, flags); | |
49 | return 0; | |
50 | } | |
51 | EXPORT_SYMBOL(__ratelimit); |