1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2012 Gleb Smirnoff <glebius@FreeBSD.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include <sys/param.h> 33 #include <sys/systm.h> 34 #include <sys/kernel.h> 35 #include <sys/lock.h> 36 #include <sys/mutex.h> 37 #include <sys/proc.h> 38 #include <sys/sched.h> 39 #include <sys/smp.h> 40 #include <sys/sysctl.h> 41 #include <vm/uma.h> 42 43 #define IN_SUBR_COUNTER_C 44 #include <sys/counter.h> 45 46 void 47 counter_u64_zero(counter_u64_t c) 48 { 49 50 counter_u64_zero_inline(c); 51 } 52 53 uint64_t 54 counter_u64_fetch(counter_u64_t c) 55 { 56 57 return (counter_u64_fetch_inline(c)); 58 } 59 60 counter_u64_t 61 counter_u64_alloc(int flags) 62 { 63 counter_u64_t r; 64 65 r = uma_zalloc(pcpu_zone_64, flags); 66 if (r != NULL) 67 counter_u64_zero(r); 68 69 return (r); 70 } 71 72 void 73 counter_u64_free(counter_u64_t c) 74 { 75 76 uma_zfree(pcpu_zone_64, c); 77 } 78 79 int 80 sysctl_handle_counter_u64(SYSCTL_HANDLER_ARGS) 81 { 82 uint64_t out; 83 int error; 84 85 out = counter_u64_fetch(*(counter_u64_t *)arg1); 86 87 error = SYSCTL_OUT(req, &out, sizeof(uint64_t)); 88 89 if (error || !req->newptr) 90 return (error); 91 92 /* 93 * Any write attempt to a counter zeroes it. 94 */ 95 counter_u64_zero(*(counter_u64_t *)arg1); 96 97 return (0); 98 } 99 100 int 101 sysctl_handle_counter_u64_array(SYSCTL_HANDLER_ARGS) 102 { 103 uint64_t *out; 104 int error; 105 106 out = malloc(arg2 * sizeof(uint64_t), M_TEMP, M_WAITOK); 107 for (int i = 0; i < arg2; i++) 108 out[i] = counter_u64_fetch(((counter_u64_t *)arg1)[i]); 109 110 error = SYSCTL_OUT(req, out, arg2 * sizeof(uint64_t)); 111 free(out, M_TEMP); 112 113 if (error || !req->newptr) 114 return (error); 115 116 /* 117 * Any write attempt to a counter zeroes it. 118 */ 119 for (int i = 0; i < arg2; i++) 120 counter_u64_zero(((counter_u64_t *)arg1)[i]); 121 122 return (0); 123 } 124 125 /* 126 * MP-friendly version of ppsratecheck(). 127 * 128 * Returns non-negative if we are in the rate, negative otherwise. 129 * 0 - rate limit not reached. 130 * -1 - rate limit reached. 131 * >0 - rate limit was reached before, and was just reset. The return value 132 * is number of events since last reset. 133 */ 134 int64_t 135 counter_ratecheck(struct counter_rate *cr, int64_t limit) 136 { 137 int64_t val; 138 int now; 139 140 val = cr->cr_over; 141 now = ticks; 142 143 if (now - cr->cr_ticks >= hz) { 144 /* 145 * Time to clear the structure, we are in the next second. 146 * First try unlocked read, and then proceed with atomic. 147 */ 148 if ((cr->cr_lock == 0) && 149 atomic_cmpset_acq_int(&cr->cr_lock, 0, 1)) { 150 /* 151 * Check if other thread has just went through the 152 * reset sequence before us. 153 */ 154 if (now - cr->cr_ticks >= hz) { 155 val = counter_u64_fetch(cr->cr_rate); 156 counter_u64_zero(cr->cr_rate); 157 cr->cr_over = 0; 158 cr->cr_ticks = now; 159 if (val <= limit) 160 val = 0; 161 } 162 atomic_store_rel_int(&cr->cr_lock, 0); 163 } else 164 /* 165 * We failed to lock, in this case other thread may 166 * be running counter_u64_zero(), so it is not safe 167 * to do an update, we skip it. 168 */ 169 return (val); 170 } 171 172 counter_u64_add(cr->cr_rate, 1); 173 if (cr->cr_over != 0) 174 return (-1); 175 if (counter_u64_fetch(cr->cr_rate) > limit) 176 val = cr->cr_over = -1; 177 178 return (val); 179 } 180