xref: /freebsd/sys/kern/subr_counter.c (revision 3f0164abf32b9b761e0a2cb4bdca3a8b84f156d4)
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 static uma_zone_t uint64_pcpu_zone;
45 
46 void
47 counter_u64_zero(counter_u64_t c)
48 {
49 
50 	counter_u64_zero_inline(c);
51 }
52 
53 uint64_t
54 counter_u64_fetch(counter_u64_t c)
55 {
56 
57 	return (counter_u64_fetch_inline(c));
58 }
59 
60 counter_u64_t
61 counter_u64_alloc(int flags)
62 {
63 	counter_u64_t r;
64 
65 	r = uma_zalloc(uint64_pcpu_zone, flags);
66 	if (r != NULL)
67 		counter_u64_zero(r);
68 
69 	return (r);
70 }
71 
72 void
73 counter_u64_free(counter_u64_t c)
74 {
75 
76 	uma_zfree(uint64_pcpu_zone, c);
77 }
78 
79 int
80 sysctl_handle_counter_u64(SYSCTL_HANDLER_ARGS)
81 {
82 	uint64_t out;
83 	int error;
84 
85 	out = counter_u64_fetch(*(counter_u64_t *)arg1);
86 
87 	error = SYSCTL_OUT(req, &out, sizeof(uint64_t));
88 
89 	if (error || !req->newptr)
90 		return (error);
91 
92 	/*
93 	 * Any write attempt to a counter zeroes it.
94 	 */
95 	counter_u64_zero(*(counter_u64_t *)arg1);
96 
97 	return (0);
98 }
99 
100 static void
101 counter_startup(void)
102 {
103 
104 	uint64_pcpu_zone = uma_zcreate("uint64 pcpu", sizeof(uint64_t),
105 	    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_PCPU);
106 }
107 SYSINIT(counter, SI_SUB_KMEM, SI_ORDER_ANY, counter_startup, NULL);
108