1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or https://opensource.org/licenses/CDDL-1.0. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright (c) 2017, Lawrence Livermore National Security, LLC. 24 */ 25 26 #include <sys/zfs_ratelimit.h> 27 28 /* 29 * Initialize rate limit struct 30 * 31 * rl: zfs_ratelimit_t struct 32 * burst: Number to allow in an interval before rate limiting 33 * interval: Interval time in seconds 34 */ 35 void 36 zfs_ratelimit_init(zfs_ratelimit_t *rl, unsigned int *burst, 37 unsigned int interval) 38 { 39 rl->count = 0; 40 rl->start = 0; 41 rl->interval = interval; 42 rl->burst = burst; 43 mutex_init(&rl->lock, NULL, MUTEX_DEFAULT, NULL); 44 } 45 46 /* 47 * Finalize rate limit struct 48 * 49 * rl: zfs_ratelimit_t struct 50 */ 51 void 52 zfs_ratelimit_fini(zfs_ratelimit_t *rl) 53 { 54 mutex_destroy(&rl->lock); 55 } 56 57 /* 58 * Re-implementation of the kernel's __ratelimit() function 59 * 60 * We had to write our own rate limiter because the kernel's __ratelimit() 61 * function annoyingly prints out how many times it rate limited to the kernel 62 * logs (and there's no way to turn it off): 63 * 64 * __ratelimit: 59 callbacks suppressed 65 * 66 * If the kernel ever allows us to disable these prints, we should go back to 67 * using __ratelimit() instead. 68 * 69 * Return values are the same as __ratelimit(): 70 * 71 * 0: If we're rate limiting 72 * 1: If we're not rate limiting. 73 */ 74 int 75 zfs_ratelimit(zfs_ratelimit_t *rl) 76 { 77 hrtime_t now; 78 79 hrtime_t elapsed; 80 int error = 1; 81 82 mutex_enter(&rl->lock); 83 84 now = gethrtime(); 85 elapsed = now - rl->start; 86 87 rl->count++; 88 if (NSEC2SEC(elapsed) >= rl->interval) { 89 rl->start = now; 90 rl->count = 0; 91 } else { 92 if (rl->count >= *rl->burst) { 93 error = 0; /* We're ratelimiting */ 94 } 95 } 96 mutex_exit(&rl->lock); 97 98 return (error); 99 } 100