projects / deliverable / linux.git / blame
| 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 | * | |
| 717115e1 DY |
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 | * | |
| 5f97a5a8 | 9 | * This file is released under the GPLv2. |
| 5f97a5a8 DY |
10 | */ |
| 11 | ||
| 3fff4c42 | 12 | #include <linux/ratelimit.h> |
| 5f97a5a8 | 13 | #include <linux/jiffies.h> |
| 8bc3bcc9 | 14 | #include <linux/export.h> |
| 5f97a5a8 DY |
15 | |
| 16 | /* | |
| 17 | * __ratelimit - rate limiting | |
| 717115e1 | 18 | * @rs: ratelimit_state data |
| 2a7268ab | 19 | * @func: name of calling function |
| 5f97a5a8 | 20 | * |
| 2a7268ab YZ |
21 | * This enforces a rate limit: not more than @rs->burst callbacks |
| 22 | * in every @rs->interval | |
| 23 | * | |
| 24 | * RETURNS: | |
| 25 | * 0 means callbacks will be suppressed. | |
| 26 | * 1 means go ahead and do it. | |
| 5f97a5a8 | 27 | */ |
| 5c828713 | 28 | int ___ratelimit(struct ratelimit_state *rs, const char *func) |
| 5f97a5a8 | 29 | { |
| 4d9c377c | 30 | unsigned long flags; |
| 979f693d | 31 | int ret; |
| 4d9c377c | 32 | |
| 717115e1 DY |
33 | if (!rs->interval) |
| 34 | return 1; | |
| 5f97a5a8 | 35 | |
| edaac8e3 IM |
36 | /* |
| 37 | * If we contend on this state's lock then almost | |
| 38 | * by definition we are too busy to print a message, | |
| 39 | * in addition to the one that will be printed by | |
| 40 | * the entity that is holding the lock already: | |
| 41 | */ | |
| 07354eb1 | 42 | if (!raw_spin_trylock_irqsave(&rs->lock, flags)) |
| 57119c34 | 43 | return 0; |
| edaac8e3 | 44 | |
| 717115e1 DY |
45 | if (!rs->begin) |
| 46 | rs->begin = jiffies; | |
| 5f97a5a8 | 47 | |
| 717115e1 DY |
48 | if (time_is_before_jiffies(rs->begin + rs->interval)) { |
| 49 | if (rs->missed) | |
| 50 | printk(KERN_WARNING "%s: %d callbacks suppressed\n", | |
| 5c828713 | 51 | func, rs->missed); |
| c2594bc3 | 52 | rs->begin = jiffies; |
| 717115e1 | 53 | rs->printed = 0; |
| 979f693d | 54 | rs->missed = 0; |
| 5f97a5a8 | 55 | } |
| 979f693d IM |
56 | if (rs->burst && rs->burst > rs->printed) { |
| 57 | rs->printed++; | |
| 58 | ret = 1; | |
| 59 | } else { | |
| 60 | rs->missed++; | |
| 61 | ret = 0; | |
| 62 | } | |
| 07354eb1 | 63 | raw_spin_unlock_irqrestore(&rs->lock, flags); |
| 717115e1 | 64 | |
| 979f693d | 65 | return ret; |
| 5f97a5a8 | 66 | } |
| 5c828713 | 67 | EXPORT_SYMBOL(___ratelimit); |