| /* | |
| * ratelimit.c - Do something with rate limit. | |
| * | |
| * Isolated from kernel/printk.c by Dave Young <hidave.darkstar@gmail.com> | |
| * | |
| * This file is released under the GPLv2. | |
| * | |
| */ | |
| #include <linux/kernel.h> | |
| #include <linux/jiffies.h> | |
| #include <linux/module.h> | |
| /* | |
| * __ratelimit - rate limiting | |
| * @ratelimit_jiffies: minimum time in jiffies between two callbacks | |
| * @ratelimit_burst: number of callbacks we do before ratelimiting | |
| * | |
| * This enforces a rate limit: not more than @ratelimit_burst callbacks | |
| * in every ratelimit_jiffies | |
| */ | |
| int __ratelimit(int ratelimit_jiffies, int ratelimit_burst) | |
| { | |
| 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; | |
| 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; | |
| 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; | |
| } | |
| missed++; | |
| spin_unlock_irqrestore(&ratelimit_lock, flags); | |
| return 0; | |
| } | |
| EXPORT_SYMBOL(__ratelimit); |