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 (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 #pragma ident "%Z%%M% %I% %E% SMI"
28
29 #include <unistd.h>
30 #include <errno.h>
31 #include <sys/mman.h>
32 #include <sys/sysmacros.h>
33 #include "vmem_base.h"
34
35 #define ALLOC_PROT PROT_READ | PROT_WRITE | PROT_EXEC
36 #define FREE_PROT PROT_NONE
37
38 #define ALLOC_FLAGS MAP_PRIVATE | MAP_ANON
39 #define FREE_FLAGS MAP_PRIVATE | MAP_ANON | MAP_NORESERVE
40
41 #define CHUNKSIZE (64*1024) /* 64 kilobytes */
42
43 static vmem_t *mmap_heap;
44
45 static void *
vmem_mmap_alloc(vmem_t * src,size_t size,int vmflags)46 vmem_mmap_alloc(vmem_t *src, size_t size, int vmflags)
47 {
48 void *ret;
49 int old_errno = errno;
50
51 ret = vmem_alloc(src, size, vmflags);
52 if (ret != NULL &&
53 mmap(ret, size, ALLOC_PROT, ALLOC_FLAGS | MAP_FIXED, -1, 0) ==
54 MAP_FAILED) {
55 vmem_free(src, ret, size);
56 vmem_reap();
57
58 ASSERT((vmflags & VM_NOSLEEP) == VM_NOSLEEP);
59 errno = old_errno;
60 return (NULL);
61 }
62
63 errno = old_errno;
64 return (ret);
65 }
66
67 static void
vmem_mmap_free(vmem_t * src,void * addr,size_t size)68 vmem_mmap_free(vmem_t *src, void *addr, size_t size)
69 {
70 int old_errno = errno;
71 (void) mmap(addr, size, FREE_PROT, FREE_FLAGS | MAP_FIXED, -1, 0);
72 vmem_free(src, addr, size);
73 errno = old_errno;
74 }
75
76 static void *
vmem_mmap_top_alloc(vmem_t * src,size_t size,int vmflags)77 vmem_mmap_top_alloc(vmem_t *src, size_t size, int vmflags)
78 {
79 void *ret;
80 void *buf;
81 int old_errno = errno;
82
83 ret = vmem_alloc(src, size, VM_NOSLEEP);
84
85 if (ret) {
86 errno = old_errno;
87 return (ret);
88 }
89 /*
90 * Need to grow the heap
91 */
92 buf = mmap((void *)CHUNKSIZE, size, FREE_PROT, FREE_FLAGS | MAP_ALIGN,
93 -1, 0);
94
95 if (buf != MAP_FAILED) {
96 ret = _vmem_extend_alloc(src, buf, size, size, vmflags);
97 if (ret != NULL)
98 return (ret);
99 else {
100 (void) munmap(buf, size);
101 errno = old_errno;
102 return (NULL);
103 }
104 } else {
105 /*
106 * Growing the heap failed. The allocation above will
107 * already have called umem_reap().
108 */
109 ASSERT((vmflags & VM_NOSLEEP) == VM_NOSLEEP);
110
111 errno = old_errno;
112 return (NULL);
113 }
114 }
115
116 vmem_t *
vmem_mmap_arena(vmem_alloc_t ** a_out,vmem_free_t ** f_out)117 vmem_mmap_arena(vmem_alloc_t **a_out, vmem_free_t **f_out)
118 {
119 size_t pagesize = sysconf(_SC_PAGESIZE);
120
121 if (mmap_heap == NULL) {
122 mmap_heap = vmem_init("mmap_top", CHUNKSIZE,
123 vmem_mmap_top_alloc, vmem_free,
124 "mmap_heap", NULL, 0, pagesize,
125 vmem_mmap_alloc, vmem_mmap_free);
126 }
127
128 if (a_out != NULL)
129 *a_out = vmem_mmap_alloc;
130 if (f_out != NULL)
131 *f_out = vmem_mmap_free;
132
133 return (mmap_heap);
134 }
135