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>
45 #include <drm/drm_mm.h>
46 #include <linux/slab.h>
47 #include <linux/seq_file.h>
48 #include <linux/export.h>
50 #define MM_UNUSED_TARGET 4
52 static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
56 enum drm_mm_search_flags flags);
57 static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm,
63 enum drm_mm_search_flags flags);
65 static void drm_mm_insert_helper(struct drm_mm_node *hole_node,
66 struct drm_mm_node *node,
67 unsigned long size, unsigned alignment,
70 struct drm_mm *mm = hole_node->mm;
71 unsigned long hole_start = drm_mm_hole_node_start(hole_node);
72 unsigned long hole_end = drm_mm_hole_node_end(hole_node);
73 unsigned long adj_start = hole_start;
74 unsigned long adj_end = hole_end;
76 BUG_ON(node->allocated);
79 mm->color_adjust(hole_node, color, &adj_start, &adj_end);
82 unsigned tmp = adj_start % alignment;
84 adj_start += alignment - tmp;
87 if (adj_start == hole_start) {
88 hole_node->hole_follows = 0;
89 list_del(&hole_node->hole_stack);
92 node->start = adj_start;
98 INIT_LIST_HEAD(&node->hole_stack);
99 list_add(&node->node_list, &hole_node->node_list);
101 BUG_ON(node->start + node->size > adj_end);
103 node->hole_follows = 0;
104 if (__drm_mm_hole_node_start(node) < hole_end) {
105 list_add(&node->hole_stack, &mm->hole_stack);
106 node->hole_follows = 1;
110 int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node)
112 struct drm_mm_node *hole;
113 unsigned long end = node->start + node->size;
114 unsigned long hole_start;
115 unsigned long hole_end;
117 BUG_ON(node == NULL);
119 /* Find the relevant hole to add our node to */
120 drm_mm_for_each_hole(hole, mm, hole_start, hole_end) {
121 if (hole_start > node->start || hole_end < end)
127 INIT_LIST_HEAD(&node->hole_stack);
128 list_add(&node->node_list, &hole->node_list);
130 if (node->start == hole_start) {
131 hole->hole_follows = 0;
132 list_del_init(&hole->hole_stack);
135 node->hole_follows = 0;
136 if (end != hole_end) {
137 list_add(&node->hole_stack, &mm->hole_stack);
138 node->hole_follows = 1;
144 WARN(1, "no hole found for node 0x%lx + 0x%lx\n",
145 node->start, node->size);
148 EXPORT_SYMBOL(drm_mm_reserve_node);
151 * Search for free space and insert a preallocated memory node. Returns
152 * -ENOSPC if no suitable free area is available. The preallocated memory node
155 int drm_mm_insert_node_generic(struct drm_mm *mm, struct drm_mm_node *node,
156 unsigned long size, unsigned alignment,
158 enum drm_mm_search_flags flags)
160 struct drm_mm_node *hole_node;
162 hole_node = drm_mm_search_free_generic(mm, size, alignment,
167 drm_mm_insert_helper(hole_node, node, size, alignment, color);
170 EXPORT_SYMBOL(drm_mm_insert_node_generic);
172 static void drm_mm_insert_helper_range(struct drm_mm_node *hole_node,
173 struct drm_mm_node *node,
174 unsigned long size, unsigned alignment,
176 unsigned long start, unsigned long end)
178 struct drm_mm *mm = hole_node->mm;
179 unsigned long hole_start = drm_mm_hole_node_start(hole_node);
180 unsigned long hole_end = drm_mm_hole_node_end(hole_node);
181 unsigned long adj_start = hole_start;
182 unsigned long adj_end = hole_end;
184 BUG_ON(!hole_node->hole_follows || node->allocated);
186 if (adj_start < start)
191 if (mm->color_adjust)
192 mm->color_adjust(hole_node, color, &adj_start, &adj_end);
195 unsigned tmp = adj_start % alignment;
197 adj_start += alignment - tmp;
200 if (adj_start == hole_start) {
201 hole_node->hole_follows = 0;
202 list_del(&hole_node->hole_stack);
205 node->start = adj_start;
211 INIT_LIST_HEAD(&node->hole_stack);
212 list_add(&node->node_list, &hole_node->node_list);
214 BUG_ON(node->start + node->size > adj_end);
215 BUG_ON(node->start + node->size > end);
217 node->hole_follows = 0;
218 if (__drm_mm_hole_node_start(node) < hole_end) {
219 list_add(&node->hole_stack, &mm->hole_stack);
220 node->hole_follows = 1;
225 * Search for free space and insert a preallocated memory node. Returns
226 * -ENOSPC if no suitable free area is available. This is for range
227 * restricted allocations. The preallocated memory node must be cleared.
229 int drm_mm_insert_node_in_range_generic(struct drm_mm *mm, struct drm_mm_node *node,
230 unsigned long size, unsigned alignment, unsigned long color,
231 unsigned long start, unsigned long end,
232 enum drm_mm_search_flags flags)
234 struct drm_mm_node *hole_node;
236 hole_node = drm_mm_search_free_in_range_generic(mm,
237 size, alignment, color,
242 drm_mm_insert_helper_range(hole_node, node,
243 size, alignment, color,
247 EXPORT_SYMBOL(drm_mm_insert_node_in_range_generic);
250 * Remove a memory node from the allocator.
252 void drm_mm_remove_node(struct drm_mm_node *node)
254 struct drm_mm *mm = node->mm;
255 struct drm_mm_node *prev_node;
257 BUG_ON(node->scanned_block || node->scanned_prev_free
258 || node->scanned_next_free);
261 list_entry(node->node_list.prev, struct drm_mm_node, node_list);
263 if (node->hole_follows) {
264 BUG_ON(__drm_mm_hole_node_start(node) ==
265 __drm_mm_hole_node_end(node));
266 list_del(&node->hole_stack);
268 BUG_ON(__drm_mm_hole_node_start(node) !=
269 __drm_mm_hole_node_end(node));
272 if (!prev_node->hole_follows) {
273 prev_node->hole_follows = 1;
274 list_add(&prev_node->hole_stack, &mm->hole_stack);
276 list_move(&prev_node->hole_stack, &mm->hole_stack);
278 list_del(&node->node_list);
281 EXPORT_SYMBOL(drm_mm_remove_node);
283 static int check_free_hole(unsigned long start, unsigned long end,
284 unsigned long size, unsigned alignment)
286 if (end - start < size)
290 unsigned tmp = start % alignment;
292 start += alignment - tmp;
295 return end >= start + size;
298 static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
302 enum drm_mm_search_flags flags)
304 struct drm_mm_node *entry;
305 struct drm_mm_node *best;
306 unsigned long adj_start;
307 unsigned long adj_end;
308 unsigned long best_size;
310 BUG_ON(mm->scanned_blocks);
315 drm_mm_for_each_hole(entry, mm, adj_start, adj_end) {
316 if (mm->color_adjust) {
317 mm->color_adjust(entry, color, &adj_start, &adj_end);
318 if (adj_end <= adj_start)
322 if (!check_free_hole(adj_start, adj_end, size, alignment))
325 if (!(flags & DRM_MM_SEARCH_BEST))
328 if (entry->size < best_size) {
330 best_size = entry->size;
337 static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm,
343 enum drm_mm_search_flags flags)
345 struct drm_mm_node *entry;
346 struct drm_mm_node *best;
347 unsigned long adj_start;
348 unsigned long adj_end;
349 unsigned long best_size;
351 BUG_ON(mm->scanned_blocks);
356 drm_mm_for_each_hole(entry, mm, adj_start, adj_end) {
357 if (adj_start < start)
362 if (mm->color_adjust) {
363 mm->color_adjust(entry, color, &adj_start, &adj_end);
364 if (adj_end <= adj_start)
368 if (!check_free_hole(adj_start, adj_end, size, alignment))
371 if (!(flags & DRM_MM_SEARCH_BEST))
374 if (entry->size < best_size) {
376 best_size = entry->size;
384 * Moves an allocation. To be used with embedded struct drm_mm_node.
386 void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new)
388 list_replace(&old->node_list, &new->node_list);
389 list_replace(&old->hole_stack, &new->hole_stack);
390 new->hole_follows = old->hole_follows;
392 new->start = old->start;
393 new->size = old->size;
394 new->color = old->color;
399 EXPORT_SYMBOL(drm_mm_replace_node);
402 * Initializa lru scanning.
404 * This simply sets up the scanning routines with the parameters for the desired
407 * Warning: As long as the scan list is non-empty, no other operations than
408 * adding/removing nodes to/from the scan list are allowed.
410 void drm_mm_init_scan(struct drm_mm *mm,
415 mm->scan_color = color;
416 mm->scan_alignment = alignment;
417 mm->scan_size = size;
418 mm->scanned_blocks = 0;
419 mm->scan_hit_start = 0;
420 mm->scan_hit_end = 0;
421 mm->scan_check_range = 0;
422 mm->prev_scanned_node = NULL;
424 EXPORT_SYMBOL(drm_mm_init_scan);
427 * Initializa lru scanning.
429 * This simply sets up the scanning routines with the parameters for the desired
430 * hole. This version is for range-restricted scans.
432 * Warning: As long as the scan list is non-empty, no other operations than
433 * adding/removing nodes to/from the scan list are allowed.
435 void drm_mm_init_scan_with_range(struct drm_mm *mm,
442 mm->scan_color = color;
443 mm->scan_alignment = alignment;
444 mm->scan_size = size;
445 mm->scanned_blocks = 0;
446 mm->scan_hit_start = 0;
447 mm->scan_hit_end = 0;
448 mm->scan_start = start;
450 mm->scan_check_range = 1;
451 mm->prev_scanned_node = NULL;
453 EXPORT_SYMBOL(drm_mm_init_scan_with_range);
456 * Add a node to the scan list that might be freed to make space for the desired
459 * Returns non-zero, if a hole has been found, zero otherwise.
461 int drm_mm_scan_add_block(struct drm_mm_node *node)
463 struct drm_mm *mm = node->mm;
464 struct drm_mm_node *prev_node;
465 unsigned long hole_start, hole_end;
466 unsigned long adj_start, adj_end;
468 mm->scanned_blocks++;
470 BUG_ON(node->scanned_block);
471 node->scanned_block = 1;
473 prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
476 node->scanned_preceeds_hole = prev_node->hole_follows;
477 prev_node->hole_follows = 1;
478 list_del(&node->node_list);
479 node->node_list.prev = &prev_node->node_list;
480 node->node_list.next = &mm->prev_scanned_node->node_list;
481 mm->prev_scanned_node = node;
483 adj_start = hole_start = drm_mm_hole_node_start(prev_node);
484 adj_end = hole_end = drm_mm_hole_node_end(prev_node);
486 if (mm->scan_check_range) {
487 if (adj_start < mm->scan_start)
488 adj_start = mm->scan_start;
489 if (adj_end > mm->scan_end)
490 adj_end = mm->scan_end;
493 if (mm->color_adjust)
494 mm->color_adjust(prev_node, mm->scan_color,
495 &adj_start, &adj_end);
497 if (check_free_hole(adj_start, adj_end,
498 mm->scan_size, mm->scan_alignment)) {
499 mm->scan_hit_start = hole_start;
500 mm->scan_hit_end = hole_end;
506 EXPORT_SYMBOL(drm_mm_scan_add_block);
509 * Remove a node from the scan list.
511 * Nodes _must_ be removed in the exact same order from the scan list as they
512 * have been added, otherwise the internal state of the memory manager will be
515 * When the scan list is empty, the selected memory nodes can be freed. An
516 * immediately following drm_mm_search_free with !DRM_MM_SEARCH_BEST will then
517 * return the just freed block (because its at the top of the free_stack list).
519 * Returns one if this block should be evicted, zero otherwise. Will always
520 * return zero when no hole has been found.
522 int drm_mm_scan_remove_block(struct drm_mm_node *node)
524 struct drm_mm *mm = node->mm;
525 struct drm_mm_node *prev_node;
527 mm->scanned_blocks--;
529 BUG_ON(!node->scanned_block);
530 node->scanned_block = 0;
532 prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
535 prev_node->hole_follows = node->scanned_preceeds_hole;
536 list_add(&node->node_list, &prev_node->node_list);
538 return (drm_mm_hole_node_end(node) > mm->scan_hit_start &&
539 node->start < mm->scan_hit_end);
541 EXPORT_SYMBOL(drm_mm_scan_remove_block);
543 int drm_mm_clean(struct drm_mm * mm)
545 struct list_head *head = &mm->head_node.node_list;
547 return (head->next->next == head);
549 EXPORT_SYMBOL(drm_mm_clean);
551 void drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size)
553 INIT_LIST_HEAD(&mm->hole_stack);
554 mm->scanned_blocks = 0;
556 /* Clever trick to avoid a special case in the free hole tracking. */
557 INIT_LIST_HEAD(&mm->head_node.node_list);
558 INIT_LIST_HEAD(&mm->head_node.hole_stack);
559 mm->head_node.hole_follows = 1;
560 mm->head_node.scanned_block = 0;
561 mm->head_node.scanned_prev_free = 0;
562 mm->head_node.scanned_next_free = 0;
563 mm->head_node.mm = mm;
564 mm->head_node.start = start + size;
565 mm->head_node.size = start - mm->head_node.start;
566 list_add_tail(&mm->head_node.hole_stack, &mm->hole_stack);
568 mm->color_adjust = NULL;
570 EXPORT_SYMBOL(drm_mm_init);
572 void drm_mm_takedown(struct drm_mm * mm)
574 WARN(!list_empty(&mm->head_node.node_list),
575 "Memory manager not clean during takedown.\n");
577 EXPORT_SYMBOL(drm_mm_takedown);
579 static unsigned long drm_mm_debug_hole(struct drm_mm_node *entry,
582 unsigned long hole_start, hole_end, hole_size;
584 if (entry->hole_follows) {
585 hole_start = drm_mm_hole_node_start(entry);
586 hole_end = drm_mm_hole_node_end(entry);
587 hole_size = hole_end - hole_start;
588 printk(KERN_DEBUG "%s 0x%08lx-0x%08lx: %8lu: free\n",
589 prefix, hole_start, hole_end,
597 void drm_mm_debug_table(struct drm_mm *mm, const char *prefix)
599 struct drm_mm_node *entry;
600 unsigned long total_used = 0, total_free = 0, total = 0;
602 total_free += drm_mm_debug_hole(&mm->head_node, prefix);
604 drm_mm_for_each_node(entry, mm) {
605 printk(KERN_DEBUG "%s 0x%08lx-0x%08lx: %8lu: used\n",
606 prefix, entry->start, entry->start + entry->size,
608 total_used += entry->size;
609 total_free += drm_mm_debug_hole(entry, prefix);
611 total = total_free + total_used;
613 printk(KERN_DEBUG "%s total: %lu, used %lu free %lu\n", prefix, total,
614 total_used, total_free);
616 EXPORT_SYMBOL(drm_mm_debug_table);
618 #if defined(CONFIG_DEBUG_FS)
619 static unsigned long drm_mm_dump_hole(struct seq_file *m, struct drm_mm_node *entry)
621 unsigned long hole_start, hole_end, hole_size;
623 if (entry->hole_follows) {
624 hole_start = drm_mm_hole_node_start(entry);
625 hole_end = drm_mm_hole_node_end(entry);
626 hole_size = hole_end - hole_start;
627 seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: free\n",
628 hole_start, hole_end, hole_size);
635 int drm_mm_dump_table(struct seq_file *m, struct drm_mm *mm)
637 struct drm_mm_node *entry;
638 unsigned long total_used = 0, total_free = 0, total = 0;
640 total_free += drm_mm_dump_hole(m, &mm->head_node);
642 drm_mm_for_each_node(entry, mm) {
643 seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: used\n",
644 entry->start, entry->start + entry->size,
646 total_used += entry->size;
647 total_free += drm_mm_dump_hole(m, entry);
649 total = total_free + total_used;
651 seq_printf(m, "total: %lu, used %lu free %lu\n", total, total_used, total_free);
654 EXPORT_SYMBOL(drm_mm_dump_table);