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/param.h> 30 #include <sys/systm.h> 31 #include <sys/kernel.h> 32 #include <sys/lock.h> 33 #include <sys/mutex.h> 34 #include <sys/proc.h> 35 #include <sys/sched.h> 36 #include <sys/smp.h> 37 #include <sys/sysctl.h> 38 #include <vm/uma.h> 39 40 #define IN_SUBR_COUNTER_C 41 #include <sys/counter.h> 42 43 void 44 counter_u64_zero(counter_u64_t c) 45 { 46 47 counter_u64_zero_inline(c); 48 } 49 50 uint64_t 51 counter_u64_fetch(counter_u64_t c) 52 { 53 54 return (counter_u64_fetch_inline(c)); 55 } 56 57 counter_u64_t 58 counter_u64_alloc(int flags) 59 { 60 61 return (uma_zalloc_pcpu(pcpu_zone_8, flags | M_ZERO)); 62 } 63 64 void 65 counter_u64_free(counter_u64_t c) 66 { 67 68 uma_zfree_pcpu(pcpu_zone_8, c); 69 } 70 71 int 72 sysctl_handle_counter_u64(SYSCTL_HANDLER_ARGS) 73 { 74 uint64_t out; 75 int error; 76 77 out = counter_u64_fetch(*(counter_u64_t *)arg1); 78 79 error = SYSCTL_OUT(req, &out, sizeof(uint64_t)); 80 81 if (error || !req->newptr) 82 return (error); 83 84 /* 85 * Any write attempt to a counter zeroes it. 86 */ 87 counter_u64_zero(*(counter_u64_t *)arg1); 88 89 return (0); 90 } 91 92 int 93 sysctl_handle_counter_u64_array(SYSCTL_HANDLER_ARGS) 94 { 95 uint64_t *out; 96 int error; 97 98 out = malloc(arg2 * sizeof(uint64_t), M_TEMP, M_WAITOK); 99 for (int i = 0; i < arg2; i++) 100 out[i] = counter_u64_fetch(((counter_u64_t *)arg1)[i]); 101 102 error = SYSCTL_OUT(req, out, arg2 * sizeof(uint64_t)); 103 free(out, M_TEMP); 104 105 if (error || !req->newptr) 106 return (error); 107 108 /* 109 * Any write attempt to a counter zeroes it. 110 */ 111 for (int i = 0; i < arg2; i++) 112 counter_u64_zero(((counter_u64_t *)arg1)[i]); 113 114 return (0); 115 } 116 117 /* 118 * MP-friendly version of ppsratecheck(). 119 * 120 * Returns non-negative if we are in the rate, negative otherwise. 121 * 0 - rate limit not reached. 122 * -1 - rate limit reached. 123 * >0 - rate limit was reached before, and was just reset. The return value 124 * is number of events since last reset. 125 */ 126 int64_t 127 counter_ratecheck(struct counter_rate *cr, int64_t limit) 128 { 129 int64_t val; 130 int now; 131 132 val = cr->cr_over; 133 now = ticks; 134 135 if ((u_int)(now - cr->cr_ticks) >= hz) { 136 /* 137 * Time to clear the structure, we are in the next second. 138 * First try unlocked read, and then proceed with atomic. 139 */ 140 if ((cr->cr_lock == 0) && 141 atomic_cmpset_acq_int(&cr->cr_lock, 0, 1)) { 142 /* 143 * Check if other thread has just went through the 144 * reset sequence before us. 145 */ 146 if ((u_int)(now - cr->cr_ticks) >= hz) { 147 val = counter_u64_fetch(cr->cr_rate); 148 counter_u64_zero(cr->cr_rate); 149 cr->cr_over = 0; 150 cr->cr_ticks = now; 151 if (val <= limit) 152 val = 0; 153 } 154 atomic_store_rel_int(&cr->cr_lock, 0); 155 } else 156 /* 157 * We failed to lock, in this case other thread may 158 * be running counter_u64_zero(), so it is not safe 159 * to do an update, we skip it. 160 */ 161 return (val); 162 } 163 164 counter_u64_add(cr->cr_rate, 1); 165 if (cr->cr_over != 0) 166 return (-1); 167 if (counter_u64_fetch(cr->cr_rate) > limit) 168 val = cr->cr_over = -1; 169 170 return (val); 171 } 172 173 void 174 counter_u64_sysinit(void *arg) 175 { 176 counter_u64_t *cp; 177 178 cp = arg; 179 *cp = counter_u64_alloc(M_WAITOK); 180 } 181 182 void 183 counter_u64_sysuninit(void *arg) 184 { 185 counter_u64_t *cp; 186 187 cp = arg; 188 counter_u64_free(*cp); 189 } 190