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cpuset.c revision 1.5 
      1 /*	$NetBSD: cpuset.c,v 1.5 2008/06/16 02:30:03 christos 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 1.5 2008/06/16 02:30:03 christos 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 
     53 struct _cpuset {
     54 	size_t		size;
     55 	unsigned int	nused;
     56 	struct _cpuset *next;
     57 	uint32_t	bits[0];
     58 };
     59 
     60 size_t
     61 /*ARGSUSED*/
     62 _cpuset_size(const cpuset_t *c)
     63 {
     64 	return sizeof(struct {
     65 	    size_t size;
     66 	    unsigned int nused;
     67 	    struct _cpuset *next;
     68 	    uint32_t bits[c->size];
     69 	});
     70 }
     71 
     72 void
     73 _cpuset_zero(cpuset_t *c)
     74 {
     75 #ifdef _KERNEL
     76 	KASSERT(c->nused == 1);
     77 #endif
     78 	(void)memset(c->bits, 0, c->size * sizeof(c->bits[0]));
     79 }
     80 
     81 int
     82 _cpuset_isset(const cpuset_t *c, cpuid_t i)
     83 {
     84 	const int j = i >> CPUSET_SHIFT;
     85 
     86 	if (j >= c->size || j < 0)
     87 		return -1;
     88 	return ((1 << (i & CPUSET_MASK)) & c->bits[j]) != 0;
     89 }
     90 
     91 int
     92 _cpuset_set(cpuset_t *c, cpuid_t i)
     93 {
     94 	const int j = i >> CPUSET_SHIFT;
     95 
     96 	if (j >= c->size || j < 0)
     97 		return -1;
     98 	c->bits[j] |= 1 << (i & CPUSET_MASK);
     99 	return 0;
    100 }
    101 
    102 int
    103 _cpuset_clr(cpuset_t *c, cpuid_t i)
    104 {
    105 	const int j = i >> CPUSET_SHIFT;
    106 
    107 	if (j >= c->size || j < 0)
    108 		return -1;
    109 	c->bits[j] &= ~(1 << (i & CPUSET_MASK));
    110 	return 0;
    111 }
    112 
    113 cpuset_t *
    114 _cpuset_create(void)
    115 {
    116 	cpuset_t s, *c;
    117 #ifdef _KERNEL
    118 	s.size = CPUSET_SIZE(MAXCPUS);
    119 	c = kmem_zalloc(_cpuset_size(&s), KM_SLEEP);
    120 #else
    121 	static int mib[2] = { CTL_HW, HW_NCPU };
    122 	size_t len;
    123 	int nc;
    124 	if (sysctl(mib, __arraycount(mib), &nc, &len, NULL, 0) == -1)
    125 		return NULL;
    126 	s.size = CPUSET_SIZE(nc);
    127 	c = calloc(1, _cpuset_size(&s));
    128 #endif
    129 	if (c != NULL) {
    130 		c->next = NULL;
    131 		c->nused = 1;
    132 		c->size = s.size;
    133 	}
    134 	return c;
    135 }
    136 
    137 void
    138 _cpuset_destroy(cpuset_t *c)
    139 {
    140 #ifdef _KERNEL
    141 	while (c) {
    142 		KASSERT(c->nused == 0);
    143 		kmem_free(c, _cpuset_size(c));
    144 		c = c->next;
    145 	}
    146 #else
    147 	free(c);
    148 #endif
    149 }
    150 
    151 #ifdef _KERNEL
    152 size_t
    153 kcpuset_nused(const cpuset_t *c)
    154 {
    155 	return c->nused;
    156 }
    157 
    158 void
    159 kcpuset_copy(cpuset_t *d, const cpuset_t *s)
    160 {
    161 
    162 	KASSERT(d->size == s->size);
    163 	KASSERT(d->nused == 1);
    164 	(void)memcpy(d->bits, s->bits, d->size * sizeof(d->bits[0]));
    165 }
    166 
    167 void
    168 kcpuset_use(cpuset_t *c)
    169 {
    170 
    171 	atomic_inc_uint(&c->nused);
    172 }
    173 
    174 void
    175 kcpuset_unuse(cpuset_t *c, cpuset_t **lst)
    176 {
    177 
    178 	if (atomic_dec_uint_nv(&c->nused) != 0)
    179 		return;
    180 	KASSERT(c->nused > 0);
    181 	KASSERT(c->next == NULL);
    182 	if (lst == NULL) {
    183 		_cpuset_destroy(c);
    184 		return;
    185 	}
    186 	c->next = *lst;
    187 	*lst = c;
    188 }
    189 #endif
    190