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
counter_u64_zero(counter_u64_t c)45 counter_u64_zero(counter_u64_t c)
46 {
47
48 counter_u64_zero_inline(c);
49 }
50
51 uint64_t
counter_u64_fetch(counter_u64_t c)52 counter_u64_fetch(counter_u64_t c)
53 {
54
55 return (counter_u64_fetch_inline(c));
56 }
57
58 counter_u64_t
counter_u64_alloc(int flags)59 counter_u64_alloc(int flags)
60 {
61
62 return (uma_zalloc_pcpu(pcpu_zone_8, flags | M_ZERO));
63 }
64
65 void
counter_u64_free(counter_u64_t c)66 counter_u64_free(counter_u64_t c)
67 {
68
69 uma_zfree_pcpu(pcpu_zone_8, c);
70 }
71
72 int
sysctl_handle_counter_u64(SYSCTL_HANDLER_ARGS)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
sysctl_handle_counter_u64_array(SYSCTL_HANDLER_ARGS)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
counter_ratecheck(struct counter_rate * cr,int64_t limit)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
counter_u64_sysinit(void * arg)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
counter_u64_sysuninit(void * arg)184 counter_u64_sysuninit(void *arg)
185 {
186 counter_u64_t *cp;
187
188 cp = arg;
189 counter_u64_free(*cp);
190 }
191