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 64 return (uma_zalloc_pcpu(pcpu_zone_64, flags | M_ZERO)); 65 } 66 67 void 68 counter_u64_free(counter_u64_t c) 69 { 70 71 uma_zfree_pcpu(pcpu_zone_64, c); 72 } 73 74 int 75 sysctl_handle_counter_u64(SYSCTL_HANDLER_ARGS) 76 { 77 uint64_t out; 78 int error; 79 80 out = counter_u64_fetch(*(counter_u64_t *)arg1); 81 82 error = SYSCTL_OUT(req, &out, sizeof(uint64_t)); 83 84 if (error || !req->newptr) 85 return (error); 86 87 /* 88 * Any write attempt to a counter zeroes it. 89 */ 90 counter_u64_zero(*(counter_u64_t *)arg1); 91 92 return (0); 93 } 94 95 int 96 sysctl_handle_counter_u64_array(SYSCTL_HANDLER_ARGS) 97 { 98 uint64_t *out; 99 int error; 100 101 out = malloc(arg2 * sizeof(uint64_t), M_TEMP, M_WAITOK); 102 for (int i = 0; i < arg2; i++) 103 out[i] = counter_u64_fetch(((counter_u64_t *)arg1)[i]); 104 105 error = SYSCTL_OUT(req, out, arg2 * sizeof(uint64_t)); 106 free(out, M_TEMP); 107 108 if (error || !req->newptr) 109 return (error); 110 111 /* 112 * Any write attempt to a counter zeroes it. 113 */ 114 for (int i = 0; i < arg2; i++) 115 counter_u64_zero(((counter_u64_t *)arg1)[i]); 116 117 return (0); 118 } 119 120 /* 121 * MP-friendly version of ppsratecheck(). 122 * 123 * Returns non-negative if we are in the rate, negative otherwise. 124 * 0 - rate limit not reached. 125 * -1 - rate limit reached. 126 * >0 - rate limit was reached before, and was just reset. The return value 127 * is number of events since last reset. 128 */ 129 int64_t 130 counter_ratecheck(struct counter_rate *cr, int64_t limit) 131 { 132 int64_t val; 133 int now; 134 135 val = cr->cr_over; 136 now = ticks; 137 138 if ((u_int)(now - cr->cr_ticks) >= hz) { 139 /* 140 * Time to clear the structure, we are in the next second. 141 * First try unlocked read, and then proceed with atomic. 142 */ 143 if ((cr->cr_lock == 0) && 144 atomic_cmpset_acq_int(&cr->cr_lock, 0, 1)) { 145 /* 146 * Check if other thread has just went through the 147 * reset sequence before us. 148 */ 149 if ((u_int)(now - cr->cr_ticks) >= hz) { 150 val = counter_u64_fetch(cr->cr_rate); 151 counter_u64_zero(cr->cr_rate); 152 cr->cr_over = 0; 153 cr->cr_ticks = now; 154 if (val <= limit) 155 val = 0; 156 } 157 atomic_store_rel_int(&cr->cr_lock, 0); 158 } else 159 /* 160 * We failed to lock, in this case other thread may 161 * be running counter_u64_zero(), so it is not safe 162 * to do an update, we skip it. 163 */ 164 return (val); 165 } 166 167 counter_u64_add(cr->cr_rate, 1); 168 if (cr->cr_over != 0) 169 return (-1); 170 if (counter_u64_fetch(cr->cr_rate) > limit) 171 val = cr->cr_over = -1; 172 173 return (val); 174 } 175 176 void 177 counter_u64_sysinit(void *arg) 178 { 179 counter_u64_t *cp; 180 181 cp = arg; 182 *cp = counter_u64_alloc(M_WAITOK); 183 } 184 185 void 186 counter_u64_sysuninit(void *arg) 187 { 188 counter_u64_t *cp; 189 190 cp = arg; 191 counter_u64_free(*cp); 192 } 193