xref: /freebsd/sys/kern/subr_counter.c (revision 40a8ac8f62b535d30349faf28cf47106b7041b83)
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