1 /**************************************************************************
3 * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., USA.
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
21 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
24 * USE OR OTHER DEALINGS IN THE SOFTWARE.
27 **************************************************************************/
30 * Generic simple memory manager implementation. Intended to be used as a base
31 * class implementation for more advanced memory managers.
33 * Note that the algorithm used is quite simple and there might be substantial
34 * performance gains if a smarter free list is implemented. Currently it is just an
35 * unordered stack of free regions. This could easily be improved if an RB-tree
36 * is used instead. At least if we expect heavy fragmentation.
38 * Aligned allocations can also see improvement.
41 * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
46 #include <linux/slab.h>
47 #include <linux/seq_file.h>
49 #define MM_UNUSED_TARGET 4
51 unsigned long drm_mm_tail_space(struct drm_mm *mm)
53 struct list_head *tail_node;
54 struct drm_mm_node *entry;
56 tail_node = mm->ml_entry.prev;
57 entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
64 int drm_mm_remove_space_from_tail(struct drm_mm *mm, unsigned long size)
66 struct list_head *tail_node;
67 struct drm_mm_node *entry;
69 tail_node = mm->ml_entry.prev;
70 entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
74 if (entry->size <= size)
81 static struct drm_mm_node *drm_mm_kmalloc(struct drm_mm *mm, int atomic)
83 struct drm_mm_node *child;
86 child = kmalloc(sizeof(*child), GFP_ATOMIC);
88 child = kmalloc(sizeof(*child), GFP_KERNEL);
90 if (unlikely(child == NULL)) {
91 spin_lock(&mm->unused_lock);
92 if (list_empty(&mm->unused_nodes))
96 list_entry(mm->unused_nodes.next,
97 struct drm_mm_node, fl_entry);
98 list_del(&child->fl_entry);
101 spin_unlock(&mm->unused_lock);
106 /* drm_mm_pre_get() - pre allocate drm_mm_node structure
107 * drm_mm: memory manager struct we are pre-allocating for
109 * Returns 0 on success or -ENOMEM if allocation fails.
111 int drm_mm_pre_get(struct drm_mm *mm)
113 struct drm_mm_node *node;
115 spin_lock(&mm->unused_lock);
116 while (mm->num_unused < MM_UNUSED_TARGET) {
117 spin_unlock(&mm->unused_lock);
118 node = kmalloc(sizeof(*node), GFP_KERNEL);
119 spin_lock(&mm->unused_lock);
121 if (unlikely(node == NULL)) {
122 int ret = (mm->num_unused < 2) ? -ENOMEM : 0;
123 spin_unlock(&mm->unused_lock);
127 list_add_tail(&node->fl_entry, &mm->unused_nodes);
129 spin_unlock(&mm->unused_lock);
132 EXPORT_SYMBOL(drm_mm_pre_get);
134 static int drm_mm_create_tail_node(struct drm_mm *mm,
136 unsigned long size, int atomic)
138 struct drm_mm_node *child;
140 child = drm_mm_kmalloc(mm, atomic);
141 if (unlikely(child == NULL))
146 child->start = start;
149 list_add_tail(&child->ml_entry, &mm->ml_entry);
150 list_add_tail(&child->fl_entry, &mm->fl_entry);
155 int drm_mm_add_space_to_tail(struct drm_mm *mm, unsigned long size, int atomic)
157 struct list_head *tail_node;
158 struct drm_mm_node *entry;
160 tail_node = mm->ml_entry.prev;
161 entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
163 return drm_mm_create_tail_node(mm, entry->start + entry->size,
170 static struct drm_mm_node *drm_mm_split_at_start(struct drm_mm_node *parent,
174 struct drm_mm_node *child;
176 child = drm_mm_kmalloc(parent->mm, atomic);
177 if (unlikely(child == NULL))
180 INIT_LIST_HEAD(&child->fl_entry);
184 child->start = parent->start;
185 child->mm = parent->mm;
187 list_add_tail(&child->ml_entry, &parent->ml_entry);
188 INIT_LIST_HEAD(&child->fl_entry);
190 parent->size -= size;
191 parent->start += size;
196 struct drm_mm_node *drm_mm_get_block_generic(struct drm_mm_node *node,
202 struct drm_mm_node *align_splitoff = NULL;
206 tmp = node->start % alignment;
210 drm_mm_split_at_start(node, alignment - tmp, atomic);
211 if (unlikely(align_splitoff == NULL))
215 if (node->size == size) {
216 list_del_init(&node->fl_entry);
219 node = drm_mm_split_at_start(node, size, atomic);
223 drm_mm_put_block(align_splitoff);
227 EXPORT_SYMBOL(drm_mm_get_block_generic);
230 * Put a block. Merge with the previous and / or next block if they are free.
231 * Otherwise add to the free stack.
234 void drm_mm_put_block(struct drm_mm_node *cur)
237 struct drm_mm *mm = cur->mm;
238 struct list_head *cur_head = &cur->ml_entry;
239 struct list_head *root_head = &mm->ml_entry;
240 struct drm_mm_node *prev_node = NULL;
241 struct drm_mm_node *next_node;
245 if (cur_head->prev != root_head) {
247 list_entry(cur_head->prev, struct drm_mm_node, ml_entry);
248 if (prev_node->free) {
249 prev_node->size += cur->size;
253 if (cur_head->next != root_head) {
255 list_entry(cur_head->next, struct drm_mm_node, ml_entry);
256 if (next_node->free) {
258 prev_node->size += next_node->size;
259 list_del(&next_node->ml_entry);
260 list_del(&next_node->fl_entry);
261 spin_lock(&mm->unused_lock);
262 if (mm->num_unused < MM_UNUSED_TARGET) {
263 list_add(&next_node->fl_entry,
268 spin_unlock(&mm->unused_lock);
270 next_node->size += cur->size;
271 next_node->start = cur->start;
278 list_add(&cur->fl_entry, &mm->fl_entry);
280 list_del(&cur->ml_entry);
281 spin_lock(&mm->unused_lock);
282 if (mm->num_unused < MM_UNUSED_TARGET) {
283 list_add(&cur->fl_entry, &mm->unused_nodes);
287 spin_unlock(&mm->unused_lock);
291 EXPORT_SYMBOL(drm_mm_put_block);
293 struct drm_mm_node *drm_mm_search_free(const struct drm_mm *mm,
295 unsigned alignment, int best_match)
297 struct list_head *list;
298 const struct list_head *free_stack = &mm->fl_entry;
299 struct drm_mm_node *entry;
300 struct drm_mm_node *best;
301 unsigned long best_size;
307 list_for_each(list, free_stack) {
308 entry = list_entry(list, struct drm_mm_node, fl_entry);
311 if (entry->size < size)
315 register unsigned tmp = entry->start % alignment;
317 wasted += alignment - tmp;
320 if (entry->size >= size + wasted) {
323 if (size < best_size) {
325 best_size = entry->size;
332 EXPORT_SYMBOL(drm_mm_search_free);
334 int drm_mm_clean(struct drm_mm * mm)
336 struct list_head *head = &mm->ml_entry;
338 return (head->next->next == head);
340 EXPORT_SYMBOL(drm_mm_clean);
342 int drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size)
344 INIT_LIST_HEAD(&mm->ml_entry);
345 INIT_LIST_HEAD(&mm->fl_entry);
346 INIT_LIST_HEAD(&mm->unused_nodes);
348 spin_lock_init(&mm->unused_lock);
350 return drm_mm_create_tail_node(mm, start, size, 0);
352 EXPORT_SYMBOL(drm_mm_init);
354 void drm_mm_takedown(struct drm_mm * mm)
356 struct list_head *bnode = mm->fl_entry.next;
357 struct drm_mm_node *entry;
358 struct drm_mm_node *next;
360 entry = list_entry(bnode, struct drm_mm_node, fl_entry);
362 if (entry->ml_entry.next != &mm->ml_entry ||
363 entry->fl_entry.next != &mm->fl_entry) {
364 DRM_ERROR("Memory manager not clean. Delaying takedown\n");
368 list_del(&entry->fl_entry);
369 list_del(&entry->ml_entry);
372 spin_lock(&mm->unused_lock);
373 list_for_each_entry_safe(entry, next, &mm->unused_nodes, fl_entry) {
374 list_del(&entry->fl_entry);
378 spin_unlock(&mm->unused_lock);
380 BUG_ON(mm->num_unused != 0);
382 EXPORT_SYMBOL(drm_mm_takedown);
384 #if defined(CONFIG_DEBUG_FS)
385 int drm_mm_dump_table(struct seq_file *m, struct drm_mm *mm)
387 struct drm_mm_node *entry;
388 int total_used = 0, total_free = 0, total = 0;
390 list_for_each_entry(entry, &mm->ml_entry, ml_entry) {
391 seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: %s\n", entry->start, entry->start + entry->size, entry->size, entry->free ? "free" : "used");
392 total += entry->size;
394 total_free += entry->size;
396 total_used += entry->size;
398 seq_printf(m, "total: %d, used %d free %d\n", total, total_free, total_used);
401 EXPORT_SYMBOL(drm_mm_dump_table);