1 /*
2 *
3 * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., USA.
4 * Copyright (c) 2009, Intel Corporation.
5 * All Rights Reserved.
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a
8 * copy of this software and associated documentation files(the
9 * "Software"), to deal in the Software without restriction, including
10 * without limitation the rights to use, copy, modify, merge, publish,
11 * distribute, sub license, and/or sell copies of the Software, and to
12 * permit persons to whom the Software is furnished to do so, subject to
13 * the following conditions:
14 *
15 * The above copyright notice and this permission notice(including the
16 * next paragraph) shall be included in all copies or substantial portions
17 * of the Software.
18 *
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
22 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
23 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
24 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
25 * USE OR OTHER DEALINGS IN THE SOFTWARE.
26 *
27 *
28 */
29
30 /*
31 * Generic simple memory manager implementation. Intended to be used as a base
32 * class implementation for more advanced memory managers.
33 *
34 * Note that the algorithm used is quite simple and there might be substantial
35 * performance gains if a smarter free list is implemented.
36 * Currently it is just an
37 * unordered stack of free regions. This could easily be improved if an RB-tree
38 * is used instead. At least if we expect heavy fragmentation.
39 *
40 * Aligned allocations can also see improvement.
41 *
42 * Authors:
43 * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
44 */
45
46 /*
47 * Copyright 2009 Sun Microsystems, Inc. All rights reserved.
48 * Use is subject to license terms.
49 */
50
51 #include "drmP.h"
52
53 unsigned long
54 drm_mm_tail_space(struct drm_mm *mm)
55 {
56 struct list_head *tail_node;
57 struct drm_mm_node *entry;
58
59 tail_node = mm->ml_entry.prev;
60 entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
61 if (!entry->free)
62 return (0);
63
64 return (entry->size);
65 }
66
67 int
68 drm_mm_remove_space_from_tail(struct drm_mm *mm, unsigned long size)
69 {
70 struct list_head *tail_node;
71 struct drm_mm_node *entry;
72
73 tail_node = mm->ml_entry.prev;
74 entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
75 if (!entry->free)
76 return (ENOMEM);
77
78 if (entry->size <= size)
79 return (ENOMEM);
80
81 entry->size -= size;
82 return (0);
83 }
84
85
86 static int
87 drm_mm_create_tail_node(struct drm_mm *mm,
88 unsigned long start,
89 unsigned long size)
90 {
91 struct drm_mm_node *child;
92
93 child = (struct drm_mm_node *)
94 drm_alloc(sizeof (*child), DRM_MEM_MM);
95 if (!child)
96 return (ENOMEM);
97
98 child->free = 1;
99 child->size = size;
100 child->start = start;
101 child->mm = mm;
102
103 list_add_tail(&child->ml_entry, &mm->ml_entry, (caddr_t)child);
104 list_add_tail(&child->fl_entry, &mm->fl_entry, (caddr_t)child);
105
106 return (0);
107 }
108
109
110 int
111 drm_mm_add_space_to_tail(struct drm_mm *mm, unsigned long size)
112 {
113 struct list_head *tail_node;
114 struct drm_mm_node *entry;
115
116 tail_node = mm->ml_entry.prev;
117 entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
118 if (!entry->free) {
119 return (drm_mm_create_tail_node(mm,
120 entry->start + entry->size, size));
121 }
122 entry->size += size;
123 return (0);
124 }
125
126 static struct drm_mm_node *
127 drm_mm_split_at_start(struct drm_mm_node *parent,
128 unsigned long size)
129 {
130 struct drm_mm_node *child;
131
132 child = (struct drm_mm_node *)
133 drm_alloc(sizeof (*child), DRM_MEM_MM);
134 if (!child)
135 return (NULL);
136
137 INIT_LIST_HEAD(&child->fl_entry);
138
139 child->free = 0;
140 child->size = size;
141 child->start = parent->start;
142 child->mm = parent->mm;
143
144 list_add_tail(&child->ml_entry, &parent->ml_entry, (caddr_t)child);
145 INIT_LIST_HEAD(&child->fl_entry);
146
147 parent->size -= size;
148 parent->start += size;
149 return (child);
150 }
151
152 /*
153 * Put a block. Merge with the previous and / or next block if they are free.
154 * Otherwise add to the free stack.
155 */
156
157 void
158 drm_mm_put_block(struct drm_mm_node *cur)
159 {
160
161 struct drm_mm *mm = cur->mm;
162 struct list_head *cur_head = &cur->ml_entry;
163 struct list_head *root_head = &mm->ml_entry;
164 struct drm_mm_node *prev_node = NULL;
165 struct drm_mm_node *next_node;
166
167 int merged = 0;
168
169 if (cur_head->prev != root_head) {
170 prev_node = list_entry(cur_head->prev,
171 struct drm_mm_node, ml_entry);
172 if (prev_node->free) {
173 prev_node->size += cur->size;
174 merged = 1;
175 }
176 }
177 if (cur_head->next != root_head) {
178 next_node = list_entry(cur_head->next,
179 struct drm_mm_node, ml_entry);
180 if (next_node->free) {
181 if (merged) {
182 prev_node->size += next_node->size;
183 list_del(&next_node->ml_entry);
184 list_del(&next_node->fl_entry);
185 drm_free(next_node,
186 sizeof (*next_node), DRM_MEM_MM);
187 } else {
188 next_node->size += cur->size;
189 next_node->start = cur->start;
190 merged = 1;
191 }
192 }
193 }
194 if (!merged) {
195 cur->free = 1;
196 list_add(&cur->fl_entry, &mm->fl_entry, (caddr_t)cur);
197 } else {
198 list_del(&cur->ml_entry);
199 drm_free(cur, sizeof (*cur), DRM_MEM_MM);
200 }
201 }
202
203 struct drm_mm_node *
204 drm_mm_get_block(struct drm_mm_node *parent,
205 unsigned long size,
206 unsigned alignment)
207 {
208
209 struct drm_mm_node *align_splitoff = NULL;
210 struct drm_mm_node *child;
211 unsigned tmp = 0;
212
213 if (alignment)
214 tmp = parent->start % alignment;
215
216 if (tmp) {
217 align_splitoff = drm_mm_split_at_start(parent, alignment - tmp);
218 if (!align_splitoff)
219 return (NULL);
220 }
221
222 if (parent->size == size) {
223 list_del_init(&parent->fl_entry);
224 parent->free = 0;
225 return (parent);
226 } else {
227 child = drm_mm_split_at_start(parent, size);
228 }
229
230 if (align_splitoff)
231 drm_mm_put_block(align_splitoff);
232
233 return (child);
234 }
235
236 struct drm_mm_node *
237 drm_mm_search_free(const struct drm_mm *mm,
238 unsigned long size,
239 unsigned alignment,
240 int best_match)
241 {
242 struct list_head *list;
243 const struct list_head *free_stack = &mm->fl_entry;
244 struct drm_mm_node *entry;
245 struct drm_mm_node *best;
246 unsigned long best_size;
247 unsigned wasted;
248
249 best = NULL;
250 best_size = ~0UL;
251
252 list_for_each(list, free_stack) {
253 entry = list_entry(list, struct drm_mm_node, fl_entry);
254 wasted = 0;
255
256 if (entry->size < size)
257 continue;
258
259 if (alignment) {
260 register unsigned tmp = entry->start % alignment;
261 if (tmp)
262 wasted += alignment - tmp;
263 }
264
265
266 if (entry->size >= size + wasted) {
267 if (!best_match)
268 return (entry);
269 if (size < best_size) {
270 best = entry;
271 best_size = entry->size;
272 }
273 }
274 }
275
276 return (best);
277 }
278
279 int
280 drm_mm_clean(struct drm_mm *mm)
281 {
282 struct list_head *head = &mm->ml_entry;
283
284 return (head->next->next == head);
285 }
286
287 int
288 drm_mm_init(struct drm_mm *mm, unsigned long start, unsigned long size)
289 {
290 INIT_LIST_HEAD(&mm->ml_entry);
291 INIT_LIST_HEAD(&mm->fl_entry);
292
293 return (drm_mm_create_tail_node(mm, start, size));
294 }
295
296
297 void
298 drm_mm_takedown(struct drm_mm *mm)
299 {
300 struct list_head *bnode = mm->fl_entry.next;
301 struct drm_mm_node *entry;
302
303 entry = list_entry(bnode, struct drm_mm_node, fl_entry);
304
305 if (entry->ml_entry.next != &mm->ml_entry ||
306 entry->fl_entry.next != &mm->fl_entry) {
307 DRM_ERROR("Memory manager not clean. Delaying takedown\n");
308 return;
309 }
310
311 list_del(&entry->fl_entry);
312 list_del(&entry->ml_entry);
313
314 drm_free(entry, sizeof (*entry), DRM_MEM_MM);
315 }
316
317 void
318 drm_mm_clean_ml(const struct drm_mm *mm)
319 {
320 const struct list_head *mlstack = &mm->ml_entry;
321 struct list_head *list, *temp;
322 struct drm_mm_node *entry;
323
324 if (mlstack->next == NULL)
325 return;
326
327 list_for_each_safe(list, temp, mlstack) {
328 entry = list_entry(list, struct drm_mm_node, ml_entry);
329 DRM_DEBUG("ml_entry 0x%x, size 0x%x, start 0x%x",
330 entry, entry->size, entry->start);
331
332 list_del(&entry->fl_entry);
333 list_del(&entry->ml_entry);
334 drm_free(entry, sizeof (*entry), DRM_MEM_MM);
335 }
336 }