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 #include <unistd.h>
28 #include <errno.h>
29 #include <sys/mman.h>
30 #include <sys/sysmacros.h>
31 #include "vmem_base.h"
32
33 #define ALLOC_PROT PROT_READ | PROT_WRITE | PROT_EXEC
34 #define FREE_PROT PROT_NONE
35
36 #define ALLOC_FLAGS MAP_PRIVATE | MAP_ANON
37 #define FREE_FLAGS MAP_PRIVATE | MAP_ANON | MAP_NORESERVE
38
39 #define CHUNKSIZE (64*1024) /* 64 kilobytes */
40
41 static vmem_t *mmap_heap;
42
43 static void *
vmem_mmap_alloc(vmem_t * src,size_t size,int vmflags)44 vmem_mmap_alloc(vmem_t *src, size_t size, int vmflags)
45 {
46 void *ret;
47 int old_errno = errno;
48
49 ret = vmem_alloc(src, size, vmflags);
50 if (ret != NULL &&
51 mmap(ret, size, ALLOC_PROT, ALLOC_FLAGS | MAP_FIXED, -1, 0) ==
52 MAP_FAILED) {
53 vmem_free(src, ret, size);
54 vmem_reap();
55
56 ASSERT((vmflags & VM_NOSLEEP) == VM_NOSLEEP);
57 errno = old_errno;
58 return (NULL);
59 }
60
61 errno = old_errno;
62 return (ret);
63 }
64
65 static void
vmem_mmap_free(vmem_t * src,void * addr,size_t size)66 vmem_mmap_free(vmem_t *src, void *addr, size_t size)
67 {
68 int old_errno = errno;
69 (void) mmap(addr, size, FREE_PROT, FREE_FLAGS | MAP_FIXED, -1, 0);
70 vmem_free(src, addr, size);
71 errno = old_errno;
72 }
73
74 static void *
vmem_mmap_top_alloc(vmem_t * src,size_t size,int vmflags)75 vmem_mmap_top_alloc(vmem_t *src, size_t size, int vmflags)
76 {
77 void *ret;
78 void *buf;
79 int old_errno = errno;
80
81 ret = vmem_alloc(src, size, VM_NOSLEEP);
82
83 if (ret) {
84 errno = old_errno;
85 return (ret);
86 }
87 /*
88 * Need to grow the heap
89 */
90 buf = mmap((void *)CHUNKSIZE, size, FREE_PROT, FREE_FLAGS | MAP_ALIGN,
91 -1, 0);
92
93 if (buf != MAP_FAILED) {
94 ret = _vmem_extend_alloc(src, buf, size, size, vmflags);
95 if (ret != NULL)
96 return (ret);
97 else {
98 (void) munmap(buf, size);
99 errno = old_errno;
100 return (NULL);
101 }
102 } else {
103 /*
104 * Growing the heap failed. The allocation above will
105 * already have called umem_reap().
106 */
107 ASSERT((vmflags & VM_NOSLEEP) == VM_NOSLEEP);
108
109 errno = old_errno;
110 return (NULL);
111 }
112 }
113
114 vmem_t *
vmem_mmap_arena(vmem_alloc_t ** a_out,vmem_free_t ** f_out)115 vmem_mmap_arena(vmem_alloc_t **a_out, vmem_free_t **f_out)
116 {
117 size_t pagesize = sysconf(_SC_PAGESIZE);
118
119 if (mmap_heap == NULL) {
120 mmap_heap = vmem_init("mmap_top", CHUNKSIZE,
121 vmem_mmap_top_alloc, vmem_free,
122 "mmap_heap", NULL, 0, pagesize,
123 vmem_mmap_alloc, vmem_mmap_free);
124 }
125
126 if (a_out != NULL)
127 *a_out = vmem_mmap_alloc;
128 if (f_out != NULL)
129 *f_out = vmem_mmap_free;
130
131 return (mmap_heap);
132 }
133