Rev 501 | Rev 533 | Go to most recent revision | Details | Compare with Previous | Last modification | View Log | RSS feed
Rev | Author | Line No. | Line |
---|---|---|---|
377 | jermar | 1 | /* |
2 | * Copyright (C) 2005 Jakub Jermar |
||
3 | * All rights reserved. |
||
4 | * |
||
5 | * Redistribution and use in source and binary forms, with or without |
||
6 | * modification, are permitted provided that the following conditions |
||
7 | * are met: |
||
8 | * |
||
9 | * - Redistributions of source code must retain the above copyright |
||
10 | * notice, this list of conditions and the following disclaimer. |
||
11 | * - Redistributions in binary form must reproduce the above copyright |
||
12 | * notice, this list of conditions and the following disclaimer in the |
||
13 | * documentation and/or other materials provided with the distribution. |
||
14 | * - The name of the author may not be used to endorse or promote products |
||
15 | * derived from this software without specific prior written permission. |
||
16 | * |
||
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
||
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
||
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
||
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
||
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
||
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
||
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
||
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
||
25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
||
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
||
27 | */ |
||
28 | |||
29 | #include <mm/buddy.h> |
||
30 | #include <mm/frame.h> |
||
31 | #include <mm/heap.h> |
||
32 | #include <arch/types.h> |
||
33 | #include <typedefs.h> |
||
34 | #include <list.h> |
||
35 | #include <debug.h> |
||
36 | |||
37 | /** Create buddy system |
||
38 | * |
||
39 | * Allocate memory for and initialize new buddy system. |
||
40 | * |
||
41 | * @param max_order The biggest allocable size will be 2^max_order. |
||
42 | * @param op Operations for new buddy system. |
||
490 | jermar | 43 | * @param data Pointer to be used by implementation. |
377 | jermar | 44 | * |
45 | * @return New buddy system. |
||
46 | */ |
||
489 | jermar | 47 | buddy_system_t *buddy_system_create(__u8 max_order, buddy_system_operations_t *op, void *data) |
377 | jermar | 48 | { |
49 | buddy_system_t *b; |
||
50 | int i; |
||
51 | |||
378 | jermar | 52 | ASSERT(max_order < BUDDY_SYSTEM_INNER_BLOCK); |
53 | |||
377 | jermar | 54 | ASSERT(op->find_buddy); |
55 | ASSERT(op->set_order); |
||
56 | ASSERT(op->get_order); |
||
57 | ASSERT(op->bisect); |
||
58 | ASSERT(op->coalesce); |
||
59 | |||
60 | /* |
||
61 | * Allocate memory for structure describing the whole buddy system. |
||
62 | */ |
||
63 | b = (buddy_system_t *) early_malloc(sizeof(buddy_system_t)); |
||
64 | |||
65 | if (b) { |
||
66 | /* |
||
67 | * Allocate memory for all orders this buddy system will work with. |
||
68 | */ |
||
69 | b->order = (link_t *) early_malloc(max_order * sizeof(link_t)); |
||
70 | if (!b->order) { |
||
71 | early_free(b); |
||
72 | return NULL; |
||
73 | } |
||
74 | |||
75 | for (i = 0; i < max_order; i++) |
||
76 | list_initialize(&b->order[i]); |
||
77 | |||
78 | b->max_order = max_order; |
||
79 | b->op = op; |
||
489 | jermar | 80 | b->data = data; |
377 | jermar | 81 | } |
82 | |||
83 | return b; |
||
84 | } |
||
85 | |||
86 | /** Allocate block from buddy system. |
||
87 | * |
||
88 | * @param b Buddy system pointer. |
||
89 | * @param i Returned block will be 2^i big. |
||
90 | * |
||
91 | * @return Block of data represented by link_t. |
||
92 | */ |
||
93 | link_t *buddy_system_alloc(buddy_system_t *b, __u8 i) |
||
94 | { |
||
95 | link_t *res, *hlp; |
||
96 | |||
97 | ASSERT(i < b->max_order); |
||
98 | |||
99 | /* |
||
100 | * If the list of order i is not empty, |
||
101 | * the request can be immediatelly satisfied. |
||
102 | */ |
||
103 | if (!list_empty(&b->order[i])) { |
||
104 | res = b->order[i].next; |
||
105 | list_remove(res); |
||
106 | return res; |
||
107 | } |
||
108 | |||
109 | /* |
||
110 | * If order i is already the maximal order, |
||
111 | * the request cannot be satisfied. |
||
112 | */ |
||
113 | if (i == b->max_order - 1) |
||
114 | return NULL; |
||
115 | |||
116 | /* |
||
117 | * Try to recursively satisfy the request from higher order lists. |
||
118 | */ |
||
119 | hlp = buddy_system_alloc(b, i + 1); |
||
120 | |||
121 | /* |
||
122 | * The request could not be satisfied |
||
123 | * from higher order lists. |
||
124 | */ |
||
125 | if (!hlp) |
||
126 | return NULL; |
||
127 | |||
128 | res = hlp; |
||
129 | |||
130 | /* |
||
131 | * Bisect the block and set order of both of its parts to i. |
||
132 | */ |
||
489 | jermar | 133 | hlp = b->op->bisect(b, res); |
134 | b->op->set_order(b, res, i); |
||
135 | b->op->set_order(b, hlp, i); |
||
377 | jermar | 136 | |
137 | /* |
||
138 | * Return the other half to buddy system. |
||
139 | */ |
||
140 | buddy_system_free(b, hlp); |
||
141 | |||
142 | return res; |
||
143 | |||
144 | } |
||
145 | |||
146 | /** Return block to buddy system. |
||
147 | * |
||
148 | * @param b Buddy system pointer. |
||
149 | * @param block Block to return. |
||
150 | */ |
||
151 | void buddy_system_free(buddy_system_t *b, link_t *block) |
||
152 | { |
||
153 | link_t *buddy, *hlp; |
||
154 | __u8 i; |
||
155 | |||
156 | /* |
||
157 | * Determine block's order. |
||
158 | */ |
||
489 | jermar | 159 | i = b->op->get_order(b, block); |
377 | jermar | 160 | |
161 | ASSERT(i < b->max_order); |
||
162 | |||
379 | jermar | 163 | if (i != b->max_order - 1) { |
377 | jermar | 164 | /* |
379 | jermar | 165 | * See if there is any buddy in the list of order i. |
377 | jermar | 166 | */ |
489 | jermar | 167 | buddy = b->op->find_buddy(b, block); |
379 | jermar | 168 | if (buddy) { |
169 | |||
489 | jermar | 170 | ASSERT(b->op->get_order(b, buddy) == i); |
377 | jermar | 171 | |
379 | jermar | 172 | /* |
173 | * Remove buddy from the list of order i. |
||
174 | */ |
||
175 | list_remove(buddy); |
||
378 | jermar | 176 | |
379 | jermar | 177 | /* |
178 | * Invalidate order of both block and buddy. |
||
179 | */ |
||
489 | jermar | 180 | b->op->set_order(b, block, BUDDY_SYSTEM_INNER_BLOCK); |
181 | b->op->set_order(b, buddy, BUDDY_SYSTEM_INNER_BLOCK); |
||
379 | jermar | 182 | |
183 | /* |
||
184 | * Coalesce block and buddy into one block. |
||
185 | */ |
||
489 | jermar | 186 | hlp = b->op->coalesce(b, block, buddy); |
377 | jermar | 187 | |
379 | jermar | 188 | /* |
189 | * Set order of the coalesced block to i + 1. |
||
190 | */ |
||
489 | jermar | 191 | b->op->set_order(b, hlp, i + 1); |
377 | jermar | 192 | |
379 | jermar | 193 | /* |
194 | * Recursively add the coalesced block to the list of order i + 1. |
||
195 | */ |
||
196 | buddy_system_free(b, hlp); |
||
197 | return; |
||
198 | } |
||
377 | jermar | 199 | } |
200 | |||
379 | jermar | 201 | /* |
202 | * Insert block into the list of order i. |
||
203 | */ |
||
204 | list_append(block, &b->order[i]); |
||
205 | |||
377 | jermar | 206 | } |