1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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 #include <sys/param.h> 31 #include <sys/systm.h> 32 #include <sys/kernel.h> 33 #include <sys/lock.h> 34 #include <sys/mutex.h> 35 #include <sys/proc.h> 36 #include <sys/sched.h> 37 #include <sys/smp.h> 38 #include <sys/sysctl.h> 39 #include <vm/uma.h> 40 41 #define IN_SUBR_COUNTER_C 42 #include <sys/counter.h> 43 44 void 45 counter_u64_zero(counter_u64_t c) 46 { 47 48 counter_u64_zero_inline(c); 49 } 50 51 uint64_t 52 counter_u64_fetch(counter_u64_t c) 53 { 54 55 return (counter_u64_fetch_inline(c)); 56 } 57 58 counter_u64_t 59 counter_u64_alloc(int flags) 60 { 61 62 return (uma_zalloc_pcpu(pcpu_zone_8, flags | M_ZERO)); 63 } 64 65 void 66 counter_u64_free(counter_u64_t c) 67 { 68 69 uma_zfree_pcpu(pcpu_zone_8, c); 70 } 71 72 int 73 sysctl_handle_counter_u64(SYSCTL_HANDLER_ARGS) 74 { 75 uint64_t out; 76 int error; 77 78 out = counter_u64_fetch(*(counter_u64_t *)arg1); 79 80 error = SYSCTL_OUT(req, &out, sizeof(uint64_t)); 81 82 if (error || !req->newptr) 83 return (error); 84 85 /* 86 * Any write attempt to a counter zeroes it. 87 */ 88 counter_u64_zero(*(counter_u64_t *)arg1); 89 90 return (0); 91 } 92 93 int 94 sysctl_handle_counter_u64_array(SYSCTL_HANDLER_ARGS) 95 { 96 uint64_t *out; 97 int error; 98 99 out = malloc(arg2 * sizeof(uint64_t), M_TEMP, M_WAITOK); 100 for (int i = 0; i < arg2; i++) 101 out[i] = counter_u64_fetch(((counter_u64_t *)arg1)[i]); 102 103 error = SYSCTL_OUT(req, out, arg2 * sizeof(uint64_t)); 104 free(out, M_TEMP); 105 106 if (error || !req->newptr) 107 return (error); 108 109 /* 110 * Any write attempt to a counter zeroes it. 111 */ 112 for (int i = 0; i < arg2; i++) 113 counter_u64_zero(((counter_u64_t *)arg1)[i]); 114 115 return (0); 116 } 117 118 /* 119 * MP-friendly version of ppsratecheck(). 120 * 121 * Returns non-negative if we are in the rate, negative otherwise. 122 * 0 - rate limit not reached. 123 * -1 - rate limit reached. 124 * >0 - rate limit was reached before, and was just reset. The return value 125 * is number of events since last reset. 126 */ 127 int64_t 128 counter_ratecheck(struct counter_rate *cr, int64_t limit) 129 { 130 int64_t val; 131 int now; 132 133 val = cr->cr_over; 134 now = ticks; 135 136 if ((u_int)(now - cr->cr_ticks) >= hz) { 137 /* 138 * Time to clear the structure, we are in the next second. 139 * First try unlocked read, and then proceed with atomic. 140 */ 141 if ((cr->cr_lock == 0) && 142 atomic_cmpset_acq_int(&cr->cr_lock, 0, 1)) { 143 /* 144 * Check if other thread has just went through the 145 * reset sequence before us. 146 */ 147 if ((u_int)(now - cr->cr_ticks) >= hz) { 148 val = counter_u64_fetch(cr->cr_rate); 149 counter_u64_zero(cr->cr_rate); 150 cr->cr_over = 0; 151 cr->cr_ticks = now; 152 if (val <= limit) 153 val = 0; 154 } 155 atomic_store_rel_int(&cr->cr_lock, 0); 156 } else 157 /* 158 * We failed to lock, in this case other thread may 159 * be running counter_u64_zero(), so it is not safe 160 * to do an update, we skip it. 161 */ 162 return (val); 163 } 164 165 counter_u64_add(cr->cr_rate, 1); 166 if (cr->cr_over != 0) 167 return (-1); 168 if (counter_u64_fetch(cr->cr_rate) > limit) 169 val = cr->cr_over = -1; 170 171 return (val); 172 } 173 174 void 175 counter_u64_sysinit(void *arg) 176 { 177 counter_u64_t *cp; 178 179 cp = arg; 180 *cp = counter_u64_alloc(M_WAITOK); 181 } 182 183 void 184 counter_u64_sysuninit(void *arg) 185 { 186 counter_u64_t *cp; 187 188 cp = arg; 189 counter_u64_free(*cp); 190 } 191