cpuset.c revision 1.2 
1/*	$NetBSD: cpuset.c,v 1.2 2008/06/15 23:41:39 rmind Exp $	*/
2
3/*-
4 * Copyright (c) 2008 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Christos Zoulas.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33#if defined(LIBC_SCCS) && !defined(lint)
34__RCSID("$NetBSD: cpuset.c,v 1.2 2008/06/15 23:41:39 rmind Exp $");
35#endif /* LIBC_SCCS and not lint */
36
37#include <sys/param.h>
38#include <sys/sched.h>
39#ifdef _KERNEL
40#include <sys/kmem.h>
41#include <lib/libkern/libkern.h>
42#include <sys/atomic.h>
43#else
44#include <string.h>
45#include <stdlib.h>
46#include <sys/sysctl.h>
47#endif
48
49#define	CPUSET_SHIFT	5
50#define	CPUSET_MASK	31
51#define CPUSET_SIZE(nc)	((nc) > 32 ? ((nc) >> CPUSET_SHIFT) : 1)
52
53struct _cpuset {
54	size_t		size;
55	unsigned int	nused;
56	struct _cpuset *next;
57	uint32_t	bits[0];
58};
59
60size_t
61_cpuset_size(const cpuset_t *c)
62{
63	return sizeof(struct {
64	    size_t size;
65	    unsigned int nused;
66	    struct _cpuset *next;
67	    uint32_t bits[c->size];
68	});
69}
70
71void
72_cpuset_zero(cpuset_t *c)
73{
74#ifdef _KERNEL
75	KASSERT(c->nused == 1);
76#endif
77	(void)memset(c->bits, 0, c->size * sizeof(c->bits[0]));
78}
79
80int
81_cpuset_isset(const cpuset_t *c, int i)
82{
83	const int j = i >> CPUSET_SHIFT;
84
85	if (j >= c->size || j < 0)
86		return -1;
87	return ((1 << (i & CPUSET_MASK)) & c->bits[j]) != 0;
88}
89
90int
91_cpuset_set(cpuset_t *c, int i)
92{
93	const int j = i >> CPUSET_SHIFT;
94
95	if (j >= c->size || j < 0)
96		return -1;
97	c->bits[j] |= 1 << (i & CPUSET_MASK);
98	return 0;
99}
100
101int
102_cpuset_clr(cpuset_t *c, int i)
103{
104	const int j = i >> CPUSET_SHIFT;
105
106	if (j >= c->size || j < 0)
107		return -1;
108	c->bits[j] &= ~(1 << (i & CPUSET_MASK));
109	return 0;
110}
111
112cpuset_t *
113_cpuset_create(void)
114{
115	cpuset_t s, *c;
116#ifdef _KERNEL
117	s.size = CPUSET_SIZE(MAXCPUS);
118	c = kmem_zalloc(_cpuset_size(&s), KM_SLEEP);
119#else
120	static int mib[2] = { CTL_HW, HW_NCPU };
121	size_t len;
122	int nc;
123	if (sysctl(mib, __arraycount(mib), &nc, &len, NULL, 0) == -1)
124		return NULL;
125	s.size = CPUSET_SIZE(nc);
126	c = calloc(1, _cpuset_size(&s));
127#endif
128	c->next = NULL;
129	c->nused = 1;
130	c->size = s.size;
131	return c;
132}
133
134void
135_cpuset_destroy(cpuset_t *c)
136{
137#ifdef _KERNEL
138	while (c) {
139		KASSERT(c->nused == 0);
140		kmem_free(c, _cpuset_size(c));
141		c = c->next;
142	}
143#else
144	free(c);
145#endif
146}
147
148#ifdef _KERNEL
149size_t
150_cpuset_nused(const cpuset_t *c)
151{
152	return c->nused;
153}
154
155void
156_cpuset_copy(cpuset_t *d, const cpuset_t *s)
157{
158
159	KASSERT(d->size == s->size);
160	KASSERT(d->nused == 1);
161	(void)memcpy(d->bits, s->bits, d->size * sizeof(d->bits[0]));
162}
163
164void
165_cpuset_use(cpuset_t *c)
166{
167
168	atomic_inc_uint(&c->nused);
169}
170
171void
172_cpuset_unuse(cpuset_t *c, cpuset_t **lst)
173{
174
175	if (atomic_dec_uint_nv(&c->nused) != 0)
176		return;
177	KASSERT(c->nused > 0);
178	KASSERT(c->next == NULL);
179	if (lst == NULL) {
180		_cpuset_destroy(c);
181		return;
182	}
183	c->next = *lst;
184	*lst = c;
185}
186#endif
187