1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /*
28 * Standalone-specific vmem routines
29 *
30 * The standalone allocator operates on a pre-existing blob of memory, the
31 * location and dimensions of which are set using vmem_stand_setsize(). We
32 * then hand out CHUNKSIZE-sized pieces of this blob, until we run out.
33 */
34
35 #define DEF_CHUNKSIZE (64 * 1024) /* 64K */
36
37 #define DEF_NREGIONS 2
38
39 #include <errno.h>
40 #include <limits.h>
41 #include <sys/sysmacros.h>
42 #include <sys/mman.h>
43 #include <unistd.h>
44 #include <strings.h>
45
46 #include "vmem_base.h"
47 #include "misc.h"
48
49 static vmem_t *stand_heap;
50
51 static size_t stand_chunksize;
52
53 typedef struct stand_region {
54 caddr_t sr_base;
55 caddr_t sr_curtop;
56 size_t sr_left;
57 } stand_region_t;
58
59 static stand_region_t stand_regions[DEF_NREGIONS];
60 static int stand_nregions;
61
62 extern void membar_producer(void);
63
64 void
vmem_stand_init(void)65 vmem_stand_init(void)
66 {
67 stand_chunksize = MAX(DEF_CHUNKSIZE, pagesize);
68
69 stand_nregions = 0;
70 }
71
72 int
vmem_stand_add(caddr_t base,size_t len)73 vmem_stand_add(caddr_t base, size_t len)
74 {
75 stand_region_t *sr = &stand_regions[stand_nregions];
76
77 ASSERT(pagesize != 0);
78
79 if (stand_nregions == DEF_NREGIONS) {
80 errno = ENOSPC;
81 return (-1); /* we don't have room -- throw it back */
82 }
83
84 /*
85 * We guarantee that only one call to `vmem_stand_add' will be
86 * active at a time, but we can't ensure that the allocator won't be
87 * in use while this function is being called. As such, we have to
88 * ensure that sr is populated and visible to other processors before
89 * allowing the allocator to access the new region.
90 */
91 sr->sr_base = base;
92 sr->sr_curtop = (caddr_t)P2ROUNDUP((ulong_t)base, stand_chunksize);
93 sr->sr_left = P2ALIGN(len - (size_t)(sr->sr_curtop - sr->sr_base),
94 stand_chunksize);
95 membar_producer();
96
97 stand_nregions++;
98
99 return (0);
100 }
101
102 static void *
stand_parent_alloc(vmem_t * src,size_t size,int vmflags)103 stand_parent_alloc(vmem_t *src, size_t size, int vmflags)
104 {
105 int old_errno = errno;
106 stand_region_t *sr;
107 size_t chksize;
108 void *ret;
109 int i;
110
111 if ((ret = vmem_alloc(src, size, VM_NOSLEEP)) != NULL) {
112 errno = old_errno;
113 return (ret);
114 }
115
116 /* We need to allocate another chunk */
117 chksize = roundup(size, stand_chunksize);
118
119 for (sr = stand_regions, i = 0; i < stand_nregions; i++, sr++) {
120 if (sr->sr_left >= chksize)
121 break;
122 }
123
124 if (i == stand_nregions) {
125 /*
126 * We don't have enough in any of our regions to satisfy the
127 * request.
128 */
129 errno = old_errno;
130 return (NULL);
131 }
132
133 if ((ret = _vmem_extend_alloc(src, sr->sr_curtop, chksize, size,
134 vmflags)) == NULL) {
135 errno = old_errno;
136 return (NULL);
137 }
138
139 bzero(sr->sr_curtop, chksize);
140
141 sr->sr_curtop += chksize;
142 sr->sr_left -= chksize;
143
144 return (ret);
145 }
146
147 vmem_t *
vmem_stand_arena(vmem_alloc_t ** a_out,vmem_free_t ** f_out)148 vmem_stand_arena(vmem_alloc_t **a_out, vmem_free_t **f_out)
149 {
150 ASSERT(stand_nregions == 1);
151
152 stand_heap = vmem_init("stand_parent", stand_chunksize,
153 stand_parent_alloc, vmem_free,
154 "stand_heap", NULL, 0, pagesize, vmem_alloc, vmem_free);
155
156 if (a_out != NULL)
157 *a_out = vmem_alloc;
158 if (f_out != NULL)
159 *f_out = vmem_free;
160
161 return (stand_heap);
162 }
163