Dave Young | 5f97a5a | 2008-04-29 00:59:43 -0700 | [diff] [blame] | 1 | /* |
| 2 | * ratelimit.c - Do something with rate limit. |
| 3 | * |
| 4 | * Isolated from kernel/printk.c by Dave Young <hidave.darkstar@gmail.com> |
| 5 | * |
Dave Young | 717115e | 2008-07-25 01:45:58 -0700 | [diff] [blame] | 6 | * 2008-05-01 rewrite the function and use a ratelimit_state data struct as |
| 7 | * parameter. Now every user can use their own standalone ratelimit_state. |
| 8 | * |
Dave Young | 5f97a5a | 2008-04-29 00:59:43 -0700 | [diff] [blame] | 9 | * This file is released under the GPLv2. |
Dave Young | 5f97a5a | 2008-04-29 00:59:43 -0700 | [diff] [blame] | 10 | */ |
| 11 | |
| 12 | #include <linux/kernel.h> |
| 13 | #include <linux/jiffies.h> |
| 14 | #include <linux/module.h> |
| 15 | |
| 16 | /* |
| 17 | * __ratelimit - rate limiting |
Dave Young | 717115e | 2008-07-25 01:45:58 -0700 | [diff] [blame] | 18 | * @rs: ratelimit_state data |
Dave Young | 5f97a5a | 2008-04-29 00:59:43 -0700 | [diff] [blame] | 19 | * |
Dave Young | 717115e | 2008-07-25 01:45:58 -0700 | [diff] [blame] | 20 | * This enforces a rate limit: not more than @rs->ratelimit_burst callbacks |
| 21 | * in every @rs->ratelimit_jiffies |
Dave Young | 5f97a5a | 2008-04-29 00:59:43 -0700 | [diff] [blame] | 22 | */ |
Dave Young | 717115e | 2008-07-25 01:45:58 -0700 | [diff] [blame] | 23 | int __ratelimit(struct ratelimit_state *rs) |
Dave Young | 5f97a5a | 2008-04-29 00:59:43 -0700 | [diff] [blame] | 24 | { |
Alexey Dobriyan | 4d9c377 | 2008-07-28 15:46:21 -0700 | [diff] [blame] | 25 | unsigned long flags; |
Ingo Molnar | 979f693 | 2009-09-22 14:44:11 +0200 | [diff] [blame^] | 26 | int ret; |
Alexey Dobriyan | 4d9c377 | 2008-07-28 15:46:21 -0700 | [diff] [blame] | 27 | |
Dave Young | 717115e | 2008-07-25 01:45:58 -0700 | [diff] [blame] | 28 | if (!rs->interval) |
| 29 | return 1; |
Dave Young | 5f97a5a | 2008-04-29 00:59:43 -0700 | [diff] [blame] | 30 | |
Ingo Molnar | 979f693 | 2009-09-22 14:44:11 +0200 | [diff] [blame^] | 31 | spin_lock_irqsave(&rs->lock, flags); |
Dave Young | 717115e | 2008-07-25 01:45:58 -0700 | [diff] [blame] | 32 | if (!rs->begin) |
| 33 | rs->begin = jiffies; |
Dave Young | 5f97a5a | 2008-04-29 00:59:43 -0700 | [diff] [blame] | 34 | |
Dave Young | 717115e | 2008-07-25 01:45:58 -0700 | [diff] [blame] | 35 | if (time_is_before_jiffies(rs->begin + rs->interval)) { |
| 36 | if (rs->missed) |
| 37 | printk(KERN_WARNING "%s: %d callbacks suppressed\n", |
| 38 | __func__, rs->missed); |
Ingo Molnar | 979f693 | 2009-09-22 14:44:11 +0200 | [diff] [blame^] | 39 | rs->begin = 0; |
Dave Young | 717115e | 2008-07-25 01:45:58 -0700 | [diff] [blame] | 40 | rs->printed = 0; |
Ingo Molnar | 979f693 | 2009-09-22 14:44:11 +0200 | [diff] [blame^] | 41 | rs->missed = 0; |
Dave Young | 5f97a5a | 2008-04-29 00:59:43 -0700 | [diff] [blame] | 42 | } |
Ingo Molnar | 979f693 | 2009-09-22 14:44:11 +0200 | [diff] [blame^] | 43 | if (rs->burst && rs->burst > rs->printed) { |
| 44 | rs->printed++; |
| 45 | ret = 1; |
| 46 | } else { |
| 47 | rs->missed++; |
| 48 | ret = 0; |
| 49 | } |
| 50 | spin_unlock_irqrestore(&rs->lock, flags); |
Dave Young | 717115e | 2008-07-25 01:45:58 -0700 | [diff] [blame] | 51 | |
Ingo Molnar | 979f693 | 2009-09-22 14:44:11 +0200 | [diff] [blame^] | 52 | return ret; |
Dave Young | 5f97a5a | 2008-04-29 00:59:43 -0700 | [diff] [blame] | 53 | } |
| 54 | EXPORT_SYMBOL(__ratelimit); |