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