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1/**************************************************************************
2 *
3 * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., USA.
4 * All Rights Reserved.
5 *
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:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
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.
25 *
26 *
27 **************************************************************************/
28
29/*
30 * Generic simple memory manager implementation. Intended to be used as a base
31 * class implementation for more advanced memory managers.
32 *
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.
37 *
38 * Aligned allocations can also see improvement.
39 *
40 * Authors:
41 * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
42 */
43
44#include "drmP.h"
45#include "drm_mm.h"
46#include <linux/slab.h>
47#include <linux/seq_file.h>
48
49#define MM_UNUSED_TARGET 4
50
51static struct drm_mm_node *drm_mm_kmalloc(struct drm_mm *mm, int atomic)
52{
53 struct drm_mm_node *child;
54
55 if (atomic)
56 child = kzalloc(sizeof(*child), GFP_ATOMIC);
57 else
58 child = kzalloc(sizeof(*child), GFP_KERNEL);
59
60 if (unlikely(child == NULL)) {
61 spin_lock(&mm->unused_lock);
62 if (list_empty(&mm->unused_nodes))
63 child = NULL;
64 else {
65 child =
66 list_entry(mm->unused_nodes.next,
67 struct drm_mm_node, node_list);
68 list_del(&child->node_list);
69 --mm->num_unused;
70 }
71 spin_unlock(&mm->unused_lock);
72 }
73 return child;
74}
75
76/* drm_mm_pre_get() - pre allocate drm_mm_node structure
77 * drm_mm: memory manager struct we are pre-allocating for
78 *
79 * Returns 0 on success or -ENOMEM if allocation fails.
80 */
81int drm_mm_pre_get(struct drm_mm *mm)
82{
83 struct drm_mm_node *node;
84
85 spin_lock(&mm->unused_lock);
86 while (mm->num_unused < MM_UNUSED_TARGET) {
87 spin_unlock(&mm->unused_lock);
88 node = kzalloc(sizeof(*node), GFP_KERNEL);
89 spin_lock(&mm->unused_lock);
90
91 if (unlikely(node == NULL)) {
92 int ret = (mm->num_unused < 2) ? -ENOMEM : 0;
93 spin_unlock(&mm->unused_lock);
94 return ret;
95 }
96 ++mm->num_unused;
97 list_add_tail(&node->node_list, &mm->unused_nodes);
98 }
99 spin_unlock(&mm->unused_lock);
100 return 0;
101}
102EXPORT_SYMBOL(drm_mm_pre_get);
103
104static inline unsigned long drm_mm_hole_node_start(struct drm_mm_node *hole_node)
105{
106 return hole_node->start + hole_node->size;
107}
108
109static inline unsigned long drm_mm_hole_node_end(struct drm_mm_node *hole_node)
110{
111 struct drm_mm_node *next_node =
112 list_entry(hole_node->node_list.next, struct drm_mm_node,
113 node_list);
114
115 return next_node->start;
116}
117
118static void drm_mm_insert_helper(struct drm_mm_node *hole_node,
119 struct drm_mm_node *node,
120 unsigned long size, unsigned alignment)
121{
122 struct drm_mm *mm = hole_node->mm;
123 unsigned long tmp = 0, wasted = 0;
124 unsigned long hole_start = drm_mm_hole_node_start(hole_node);
125 unsigned long hole_end = drm_mm_hole_node_end(hole_node);
126
127 BUG_ON(!hole_node->hole_follows || node->allocated);
128
129 if (alignment)
130 tmp = hole_start % alignment;
131
132 if (!tmp) {
133 hole_node->hole_follows = 0;
134 list_del_init(&hole_node->hole_stack);
135 } else
136 wasted = alignment - tmp;
137
138 node->start = hole_start + wasted;
139 node->size = size;
140 node->mm = mm;
141 node->allocated = 1;
142
143 INIT_LIST_HEAD(&node->hole_stack);
144 list_add(&node->node_list, &hole_node->node_list);
145
146 BUG_ON(node->start + node->size > hole_end);
147
148 if (node->start + node->size < hole_end) {
149 list_add(&node->hole_stack, &mm->hole_stack);
150 node->hole_follows = 1;
151 } else {
152 node->hole_follows = 0;
153 }
154}
155
156struct drm_mm_node *drm_mm_get_block_generic(struct drm_mm_node *hole_node,
157 unsigned long size,
158 unsigned alignment,
159 int atomic)
160{
161 struct drm_mm_node *node;
162
163 node = drm_mm_kmalloc(hole_node->mm, atomic);
164 if (unlikely(node == NULL))
165 return NULL;
166
167 drm_mm_insert_helper(hole_node, node, size, alignment);
168
169 return node;
170}
171EXPORT_SYMBOL(drm_mm_get_block_generic);
172
173/**
174 * Search for free space and insert a preallocated memory node. Returns
175 * -ENOSPC if no suitable free area is available. The preallocated memory node
176 * must be cleared.
177 */
178int drm_mm_insert_node(struct drm_mm *mm, struct drm_mm_node *node,
179 unsigned long size, unsigned alignment)
180{
181 struct drm_mm_node *hole_node;
182
183 hole_node = drm_mm_search_free(mm, size, alignment, 0);
184 if (!hole_node)
185 return -ENOSPC;
186
187 drm_mm_insert_helper(hole_node, node, size, alignment);
188
189 return 0;
190}
191EXPORT_SYMBOL(drm_mm_insert_node);
192
193static void drm_mm_insert_helper_range(struct drm_mm_node *hole_node,
194 struct drm_mm_node *node,
195 unsigned long size, unsigned alignment,
196 unsigned long start, unsigned long end)
197{
198 struct drm_mm *mm = hole_node->mm;
199 unsigned long tmp = 0, wasted = 0;
200 unsigned long hole_start = drm_mm_hole_node_start(hole_node);
201 unsigned long hole_end = drm_mm_hole_node_end(hole_node);
202
203 BUG_ON(!hole_node->hole_follows || node->allocated);
204
205 if (hole_start < start)
206 wasted += start - hole_start;
207 if (alignment)
208 tmp = (hole_start + wasted) % alignment;
209
210 if (tmp)
211 wasted += alignment - tmp;
212
213 if (!wasted) {
214 hole_node->hole_follows = 0;
215 list_del_init(&hole_node->hole_stack);
216 }
217
218 node->start = hole_start + wasted;
219 node->size = size;
220 node->mm = mm;
221 node->allocated = 1;
222
223 INIT_LIST_HEAD(&node->hole_stack);
224 list_add(&node->node_list, &hole_node->node_list);
225
226 BUG_ON(node->start + node->size > hole_end);
227 BUG_ON(node->start + node->size > end);
228
229 if (node->start + node->size < hole_end) {
230 list_add(&node->hole_stack, &mm->hole_stack);
231 node->hole_follows = 1;
232 } else {
233 node->hole_follows = 0;
234 }
235}
236
237struct drm_mm_node *drm_mm_get_block_range_generic(struct drm_mm_node *hole_node,
238 unsigned long size,
239 unsigned alignment,
240 unsigned long start,
241 unsigned long end,
242 int atomic)
243{
244 struct drm_mm_node *node;
245
246 node = drm_mm_kmalloc(hole_node->mm, atomic);
247 if (unlikely(node == NULL))
248 return NULL;
249
250 drm_mm_insert_helper_range(hole_node, node, size, alignment,
251 start, end);
252
253 return node;
254}
255EXPORT_SYMBOL(drm_mm_get_block_range_generic);
256
257/**
258 * Search for free space and insert a preallocated memory node. Returns
259 * -ENOSPC if no suitable free area is available. This is for range
260 * restricted allocations. The preallocated memory node must be cleared.
261 */
262int drm_mm_insert_node_in_range(struct drm_mm *mm, struct drm_mm_node *node,
263 unsigned long size, unsigned alignment,
264 unsigned long start, unsigned long end)
265{
266 struct drm_mm_node *hole_node;
267
268 hole_node = drm_mm_search_free_in_range(mm, size, alignment,
269 start, end, 0);
270 if (!hole_node)
271 return -ENOSPC;
272
273 drm_mm_insert_helper_range(hole_node, node, size, alignment,
274 start, end);
275
276 return 0;
277}
278EXPORT_SYMBOL(drm_mm_insert_node_in_range);
279
280/**
281 * Remove a memory node from the allocator.
282 */
283void drm_mm_remove_node(struct drm_mm_node *node)
284{
285 struct drm_mm *mm = node->mm;
286 struct drm_mm_node *prev_node;
287
288 BUG_ON(node->scanned_block || node->scanned_prev_free
289 || node->scanned_next_free);
290
291 prev_node =
292 list_entry(node->node_list.prev, struct drm_mm_node, node_list);
293
294 if (node->hole_follows) {
295 BUG_ON(drm_mm_hole_node_start(node)
296 == drm_mm_hole_node_end(node));
297 list_del(&node->hole_stack);
298 } else
299 BUG_ON(drm_mm_hole_node_start(node)
300 != drm_mm_hole_node_end(node));
301
302 if (!prev_node->hole_follows) {
303 prev_node->hole_follows = 1;
304 list_add(&prev_node->hole_stack, &mm->hole_stack);
305 } else
306 list_move(&prev_node->hole_stack, &mm->hole_stack);
307
308 list_del(&node->node_list);
309 node->allocated = 0;
310}
311EXPORT_SYMBOL(drm_mm_remove_node);
312
313/*
314 * Remove a memory node from the allocator and free the allocated struct
315 * drm_mm_node. Only to be used on a struct drm_mm_node obtained by one of the
316 * drm_mm_get_block functions.
317 */
318void drm_mm_put_block(struct drm_mm_node *node)
319{
320
321 struct drm_mm *mm = node->mm;
322
323 drm_mm_remove_node(node);
324
325 spin_lock(&mm->unused_lock);
326 if (mm->num_unused < MM_UNUSED_TARGET) {
327 list_add(&node->node_list, &mm->unused_nodes);
328 ++mm->num_unused;
329 } else
330 kfree(node);
331 spin_unlock(&mm->unused_lock);
332}
333EXPORT_SYMBOL(drm_mm_put_block);
334
335static int check_free_hole(unsigned long start, unsigned long end,
336 unsigned long size, unsigned alignment)
337{
338 unsigned wasted = 0;
339
340 if (end - start < size)
341 return 0;
342
343 if (alignment) {
344 unsigned tmp = start % alignment;
345 if (tmp)
346 wasted = alignment - tmp;
347 }
348
349 if (end >= start + size + wasted) {
350 return 1;
351 }
352
353 return 0;
354}
355
356struct drm_mm_node *drm_mm_search_free(const struct drm_mm *mm,
357 unsigned long size,
358 unsigned alignment, int best_match)
359{
360 struct drm_mm_node *entry;
361 struct drm_mm_node *best;
362 unsigned long best_size;
363
364 BUG_ON(mm->scanned_blocks);
365
366 best = NULL;
367 best_size = ~0UL;
368
369 list_for_each_entry(entry, &mm->hole_stack, hole_stack) {
370 BUG_ON(!entry->hole_follows);
371 if (!check_free_hole(drm_mm_hole_node_start(entry),
372 drm_mm_hole_node_end(entry),
373 size, alignment))
374 continue;
375
376 if (!best_match)
377 return entry;
378
379 if (entry->size < best_size) {
380 best = entry;
381 best_size = entry->size;
382 }
383 }
384
385 return best;
386}
387EXPORT_SYMBOL(drm_mm_search_free);
388
389struct drm_mm_node *drm_mm_search_free_in_range(const struct drm_mm *mm,
390 unsigned long size,
391 unsigned alignment,
392 unsigned long start,
393 unsigned long end,
394 int best_match)
395{
396 struct drm_mm_node *entry;
397 struct drm_mm_node *best;
398 unsigned long best_size;
399
400 BUG_ON(mm->scanned_blocks);
401
402 best = NULL;
403 best_size = ~0UL;
404
405 list_for_each_entry(entry, &mm->hole_stack, hole_stack) {
406 unsigned long adj_start = drm_mm_hole_node_start(entry) < start ?
407 start : drm_mm_hole_node_start(entry);
408 unsigned long adj_end = drm_mm_hole_node_end(entry) > end ?
409 end : drm_mm_hole_node_end(entry);
410
411 BUG_ON(!entry->hole_follows);
412 if (!check_free_hole(adj_start, adj_end, size, alignment))
413 continue;
414
415 if (!best_match)
416 return entry;
417
418 if (entry->size < best_size) {
419 best = entry;
420 best_size = entry->size;
421 }
422 }
423
424 return best;
425}
426EXPORT_SYMBOL(drm_mm_search_free_in_range);
427
428/**
429 * Moves an allocation. To be used with embedded struct drm_mm_node.
430 */
431void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new)
432{
433 list_replace(&old->node_list, &new->node_list);
434 list_replace(&old->hole_stack, &new->hole_stack);
435 new->hole_follows = old->hole_follows;
436 new->mm = old->mm;
437 new->start = old->start;
438 new->size = old->size;
439
440 old->allocated = 0;
441 new->allocated = 1;
442}
443EXPORT_SYMBOL(drm_mm_replace_node);
444
445/**
446 * Initializa lru scanning.
447 *
448 * This simply sets up the scanning routines with the parameters for the desired
449 * hole.
450 *
451 * Warning: As long as the scan list is non-empty, no other operations than
452 * adding/removing nodes to/from the scan list are allowed.
453 */
454void drm_mm_init_scan(struct drm_mm *mm, unsigned long size,
455 unsigned alignment)
456{
457 mm->scan_alignment = alignment;
458 mm->scan_size = size;
459 mm->scanned_blocks = 0;
460 mm->scan_hit_start = 0;
461 mm->scan_hit_size = 0;
462 mm->scan_check_range = 0;
463 mm->prev_scanned_node = NULL;
464}
465EXPORT_SYMBOL(drm_mm_init_scan);
466
467/**
468 * Initializa lru scanning.
469 *
470 * This simply sets up the scanning routines with the parameters for the desired
471 * hole. This version is for range-restricted scans.
472 *
473 * Warning: As long as the scan list is non-empty, no other operations than
474 * adding/removing nodes to/from the scan list are allowed.
475 */
476void drm_mm_init_scan_with_range(struct drm_mm *mm, unsigned long size,
477 unsigned alignment,
478 unsigned long start,
479 unsigned long end)
480{
481 mm->scan_alignment = alignment;
482 mm->scan_size = size;
483 mm->scanned_blocks = 0;
484 mm->scan_hit_start = 0;
485 mm->scan_hit_size = 0;
486 mm->scan_start = start;
487 mm->scan_end = end;
488 mm->scan_check_range = 1;
489 mm->prev_scanned_node = NULL;
490}
491EXPORT_SYMBOL(drm_mm_init_scan_with_range);
492
493/**
494 * Add a node to the scan list that might be freed to make space for the desired
495 * hole.
496 *
497 * Returns non-zero, if a hole has been found, zero otherwise.
498 */
499int drm_mm_scan_add_block(struct drm_mm_node *node)
500{
501 struct drm_mm *mm = node->mm;
502 struct drm_mm_node *prev_node;
503 unsigned long hole_start, hole_end;
504 unsigned long adj_start;
505 unsigned long adj_end;
506
507 mm->scanned_blocks++;
508
509 BUG_ON(node->scanned_block);
510 node->scanned_block = 1;
511
512 prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
513 node_list);
514
515 node->scanned_preceeds_hole = prev_node->hole_follows;
516 prev_node->hole_follows = 1;
517 list_del(&node->node_list);
518 node->node_list.prev = &prev_node->node_list;
519 node->node_list.next = &mm->prev_scanned_node->node_list;
520 mm->prev_scanned_node = node;
521
522 hole_start = drm_mm_hole_node_start(prev_node);
523 hole_end = drm_mm_hole_node_end(prev_node);
524 if (mm->scan_check_range) {
525 adj_start = hole_start < mm->scan_start ?
526 mm->scan_start : hole_start;
527 adj_end = hole_end > mm->scan_end ?
528 mm->scan_end : hole_end;
529 } else {
530 adj_start = hole_start;
531 adj_end = hole_end;
532 }
533
534 if (check_free_hole(adj_start , adj_end,
535 mm->scan_size, mm->scan_alignment)) {
536 mm->scan_hit_start = hole_start;
537 mm->scan_hit_size = hole_end;
538
539 return 1;
540 }
541
542 return 0;
543}
544EXPORT_SYMBOL(drm_mm_scan_add_block);
545
546/**
547 * Remove a node from the scan list.
548 *
549 * Nodes _must_ be removed in the exact same order from the scan list as they
550 * have been added, otherwise the internal state of the memory manager will be
551 * corrupted.
552 *
553 * When the scan list is empty, the selected memory nodes can be freed. An
554 * immediately following drm_mm_search_free with best_match = 0 will then return
555 * the just freed block (because its at the top of the free_stack list).
556 *
557 * Returns one if this block should be evicted, zero otherwise. Will always
558 * return zero when no hole has been found.
559 */
560int drm_mm_scan_remove_block(struct drm_mm_node *node)
561{
562 struct drm_mm *mm = node->mm;
563 struct drm_mm_node *prev_node;
564
565 mm->scanned_blocks--;
566
567 BUG_ON(!node->scanned_block);
568 node->scanned_block = 0;
569
570 prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
571 node_list);
572
573 prev_node->hole_follows = node->scanned_preceeds_hole;
574 INIT_LIST_HEAD(&node->node_list);
575 list_add(&node->node_list, &prev_node->node_list);
576
577 /* Only need to check for containement because start&size for the
578 * complete resulting free block (not just the desired part) is
579 * stored. */
580 if (node->start >= mm->scan_hit_start &&
581 node->start + node->size
582 <= mm->scan_hit_start + mm->scan_hit_size) {
583 return 1;
584 }
585
586 return 0;
587}
588EXPORT_SYMBOL(drm_mm_scan_remove_block);
589
590int drm_mm_clean(struct drm_mm * mm)
591{
592 struct list_head *head = &mm->head_node.node_list;
593
594 return (head->next->next == head);
595}
596EXPORT_SYMBOL(drm_mm_clean);
597
598int drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size)
599{
600 INIT_LIST_HEAD(&mm->hole_stack);
601 INIT_LIST_HEAD(&mm->unused_nodes);
602 mm->num_unused = 0;
603 mm->scanned_blocks = 0;
604 spin_lock_init(&mm->unused_lock);
605
606 /* Clever trick to avoid a special case in the free hole tracking. */
607 INIT_LIST_HEAD(&mm->head_node.node_list);
608 INIT_LIST_HEAD(&mm->head_node.hole_stack);
609 mm->head_node.hole_follows = 1;
610 mm->head_node.scanned_block = 0;
611 mm->head_node.scanned_prev_free = 0;
612 mm->head_node.scanned_next_free = 0;
613 mm->head_node.mm = mm;
614 mm->head_node.start = start + size;
615 mm->head_node.size = start - mm->head_node.start;
616 list_add_tail(&mm->head_node.hole_stack, &mm->hole_stack);
617
618 return 0;
619}
620EXPORT_SYMBOL(drm_mm_init);
621
622void drm_mm_takedown(struct drm_mm * mm)
623{
624 struct drm_mm_node *entry, *next;
625
626 if (!list_empty(&mm->head_node.node_list)) {
627 DRM_ERROR("Memory manager not clean. Delaying takedown\n");
628 return;
629 }
630
631 spin_lock(&mm->unused_lock);
632 list_for_each_entry_safe(entry, next, &mm->unused_nodes, node_list) {
633 list_del(&entry->node_list);
634 kfree(entry);
635 --mm->num_unused;
636 }
637 spin_unlock(&mm->unused_lock);
638
639 BUG_ON(mm->num_unused != 0);
640}
641EXPORT_SYMBOL(drm_mm_takedown);
642
643void drm_mm_debug_table(struct drm_mm *mm, const char *prefix)
644{
645 struct drm_mm_node *entry;
646 unsigned long total_used = 0, total_free = 0, total = 0;
647 unsigned long hole_start, hole_end, hole_size;
648
649 hole_start = drm_mm_hole_node_start(&mm->head_node);
650 hole_end = drm_mm_hole_node_end(&mm->head_node);
651 hole_size = hole_end - hole_start;
652 if (hole_size)
653 printk(KERN_DEBUG "%s 0x%08lx-0x%08lx: %8lu: free\n",
654 prefix, hole_start, hole_end,
655 hole_size);
656 total_free += hole_size;
657
658 drm_mm_for_each_node(entry, mm) {
659 printk(KERN_DEBUG "%s 0x%08lx-0x%08lx: %8lu: used\n",
660 prefix, entry->start, entry->start + entry->size,
661 entry->size);
662 total_used += entry->size;
663
664 if (entry->hole_follows) {
665 hole_start = drm_mm_hole_node_start(entry);
666 hole_end = drm_mm_hole_node_end(entry);
667 hole_size = hole_end - hole_start;
668 printk(KERN_DEBUG "%s 0x%08lx-0x%08lx: %8lu: free\n",
669 prefix, hole_start, hole_end,
670 hole_size);
671 total_free += hole_size;
672 }
673 }
674 total = total_free + total_used;
675
676 printk(KERN_DEBUG "%s total: %lu, used %lu free %lu\n", prefix, total,
677 total_used, total_free);
678}
679EXPORT_SYMBOL(drm_mm_debug_table);
680
681#if defined(CONFIG_DEBUG_FS)
682int drm_mm_dump_table(struct seq_file *m, struct drm_mm *mm)
683{
684 struct drm_mm_node *entry;
685 unsigned long total_used = 0, total_free = 0, total = 0;
686 unsigned long hole_start, hole_end, hole_size;
687
688 hole_start = drm_mm_hole_node_start(&mm->head_node);
689 hole_end = drm_mm_hole_node_end(&mm->head_node);
690 hole_size = hole_end - hole_start;
691 if (hole_size)
692 seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: free\n",
693 hole_start, hole_end, hole_size);
694 total_free += hole_size;
695
696 drm_mm_for_each_node(entry, mm) {
697 seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: used\n",
698 entry->start, entry->start + entry->size,
699 entry->size);
700 total_used += entry->size;
701 if (entry->hole_follows) {
702 hole_start = drm_mm_hole_node_start(entry);
703 hole_end = drm_mm_hole_node_end(entry);
704 hole_size = hole_end - hole_start;
705 seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: free\n",
706 hole_start, hole_end, hole_size);
707 total_free += hole_size;
708 }
709 }
710 total = total_free + total_used;
711
712 seq_printf(m, "total: %lu, used %lu free %lu\n", total, total_used, total_free);
713 return 0;
714}
715EXPORT_SYMBOL(drm_mm_dump_table);
716#endif
1/**************************************************************************
2 *
3 * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., USA.
4 * Copyright 2016 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. Currently it is
36 * just an unordered stack of free regions. This could easily be improved if
37 * an RB-tree is used instead. At least if we expect heavy fragmentation.
38 *
39 * Aligned allocations can also see improvement.
40 *
41 * Authors:
42 * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
43 */
44
45#include <linux/export.h>
46#include <linux/interval_tree_generic.h>
47#include <linux/seq_file.h>
48#include <linux/slab.h>
49#include <linux/stacktrace.h>
50
51#include <drm/drm_mm.h>
52
53/**
54 * DOC: Overview
55 *
56 * drm_mm provides a simple range allocator. The drivers are free to use the
57 * resource allocator from the linux core if it suits them, the upside of drm_mm
58 * is that it's in the DRM core. Which means that it's easier to extend for
59 * some of the crazier special purpose needs of gpus.
60 *
61 * The main data struct is &drm_mm, allocations are tracked in &drm_mm_node.
62 * Drivers are free to embed either of them into their own suitable
63 * datastructures. drm_mm itself will not do any memory allocations of its own,
64 * so if drivers choose not to embed nodes they need to still allocate them
65 * themselves.
66 *
67 * The range allocator also supports reservation of preallocated blocks. This is
68 * useful for taking over initial mode setting configurations from the firmware,
69 * where an object needs to be created which exactly matches the firmware's
70 * scanout target. As long as the range is still free it can be inserted anytime
71 * after the allocator is initialized, which helps with avoiding looped
72 * dependencies in the driver load sequence.
73 *
74 * drm_mm maintains a stack of most recently freed holes, which of all
75 * simplistic datastructures seems to be a fairly decent approach to clustering
76 * allocations and avoiding too much fragmentation. This means free space
77 * searches are O(num_holes). Given that all the fancy features drm_mm supports
78 * something better would be fairly complex and since gfx thrashing is a fairly
79 * steep cliff not a real concern. Removing a node again is O(1).
80 *
81 * drm_mm supports a few features: Alignment and range restrictions can be
82 * supplied. Furthermore every &drm_mm_node has a color value (which is just an
83 * opaque unsigned long) which in conjunction with a driver callback can be used
84 * to implement sophisticated placement restrictions. The i915 DRM driver uses
85 * this to implement guard pages between incompatible caching domains in the
86 * graphics TT.
87 *
88 * Two behaviors are supported for searching and allocating: bottom-up and
89 * top-down. The default is bottom-up. Top-down allocation can be used if the
90 * memory area has different restrictions, or just to reduce fragmentation.
91 *
92 * Finally iteration helpers to walk all nodes and all holes are provided as are
93 * some basic allocator dumpers for debugging.
94 *
95 * Note that this range allocator is not thread-safe, drivers need to protect
96 * modifications with their own locking. The idea behind this is that for a full
97 * memory manager additional data needs to be protected anyway, hence internal
98 * locking would be fully redundant.
99 */
100
101#ifdef CONFIG_DRM_DEBUG_MM
102#include <linux/stackdepot.h>
103
104#define STACKDEPTH 32
105#define BUFSZ 4096
106
107static noinline void save_stack(struct drm_mm_node *node)
108{
109 unsigned long entries[STACKDEPTH];
110 unsigned int n;
111
112 n = stack_trace_save(entries, ARRAY_SIZE(entries), 1);
113
114 /* May be called under spinlock, so avoid sleeping */
115 node->stack = stack_depot_save(entries, n, GFP_NOWAIT);
116}
117
118static void show_leaks(struct drm_mm *mm)
119{
120 struct drm_mm_node *node;
121 char *buf;
122
123 buf = kmalloc(BUFSZ, GFP_KERNEL);
124 if (!buf)
125 return;
126
127 list_for_each_entry(node, drm_mm_nodes(mm), node_list) {
128 if (!node->stack) {
129 DRM_ERROR("node [%08llx + %08llx]: unknown owner\n",
130 node->start, node->size);
131 continue;
132 }
133
134 stack_depot_snprint(node->stack, buf, BUFSZ, 0);
135 DRM_ERROR("node [%08llx + %08llx]: inserted at\n%s",
136 node->start, node->size, buf);
137 }
138
139 kfree(buf);
140}
141
142#undef STACKDEPTH
143#undef BUFSZ
144#else
145static void save_stack(struct drm_mm_node *node) { }
146static void show_leaks(struct drm_mm *mm) { }
147#endif
148
149#define START(node) ((node)->start)
150#define LAST(node) ((node)->start + (node)->size - 1)
151
152INTERVAL_TREE_DEFINE(struct drm_mm_node, rb,
153 u64, __subtree_last,
154 START, LAST, static inline, drm_mm_interval_tree)
155
156struct drm_mm_node *
157__drm_mm_interval_first(const struct drm_mm *mm, u64 start, u64 last)
158{
159 return drm_mm_interval_tree_iter_first((struct rb_root_cached *)&mm->interval_tree,
160 start, last) ?: (struct drm_mm_node *)&mm->head_node;
161}
162EXPORT_SYMBOL(__drm_mm_interval_first);
163
164static void drm_mm_interval_tree_add_node(struct drm_mm_node *hole_node,
165 struct drm_mm_node *node)
166{
167 struct drm_mm *mm = hole_node->mm;
168 struct rb_node **link, *rb;
169 struct drm_mm_node *parent;
170 bool leftmost;
171
172 node->__subtree_last = LAST(node);
173
174 if (drm_mm_node_allocated(hole_node)) {
175 rb = &hole_node->rb;
176 while (rb) {
177 parent = rb_entry(rb, struct drm_mm_node, rb);
178 if (parent->__subtree_last >= node->__subtree_last)
179 break;
180
181 parent->__subtree_last = node->__subtree_last;
182 rb = rb_parent(rb);
183 }
184
185 rb = &hole_node->rb;
186 link = &hole_node->rb.rb_right;
187 leftmost = false;
188 } else {
189 rb = NULL;
190 link = &mm->interval_tree.rb_root.rb_node;
191 leftmost = true;
192 }
193
194 while (*link) {
195 rb = *link;
196 parent = rb_entry(rb, struct drm_mm_node, rb);
197 if (parent->__subtree_last < node->__subtree_last)
198 parent->__subtree_last = node->__subtree_last;
199 if (node->start < parent->start) {
200 link = &parent->rb.rb_left;
201 } else {
202 link = &parent->rb.rb_right;
203 leftmost = false;
204 }
205 }
206
207 rb_link_node(&node->rb, rb, link);
208 rb_insert_augmented_cached(&node->rb, &mm->interval_tree, leftmost,
209 &drm_mm_interval_tree_augment);
210}
211
212#define HOLE_SIZE(NODE) ((NODE)->hole_size)
213#define HOLE_ADDR(NODE) (__drm_mm_hole_node_start(NODE))
214
215static u64 rb_to_hole_size(struct rb_node *rb)
216{
217 return rb_entry(rb, struct drm_mm_node, rb_hole_size)->hole_size;
218}
219
220static void insert_hole_size(struct rb_root_cached *root,
221 struct drm_mm_node *node)
222{
223 struct rb_node **link = &root->rb_root.rb_node, *rb = NULL;
224 u64 x = node->hole_size;
225 bool first = true;
226
227 while (*link) {
228 rb = *link;
229 if (x > rb_to_hole_size(rb)) {
230 link = &rb->rb_left;
231 } else {
232 link = &rb->rb_right;
233 first = false;
234 }
235 }
236
237 rb_link_node(&node->rb_hole_size, rb, link);
238 rb_insert_color_cached(&node->rb_hole_size, root, first);
239}
240
241RB_DECLARE_CALLBACKS_MAX(static, augment_callbacks,
242 struct drm_mm_node, rb_hole_addr,
243 u64, subtree_max_hole, HOLE_SIZE)
244
245static void insert_hole_addr(struct rb_root *root, struct drm_mm_node *node)
246{
247 struct rb_node **link = &root->rb_node, *rb_parent = NULL;
248 u64 start = HOLE_ADDR(node), subtree_max_hole = node->subtree_max_hole;
249 struct drm_mm_node *parent;
250
251 while (*link) {
252 rb_parent = *link;
253 parent = rb_entry(rb_parent, struct drm_mm_node, rb_hole_addr);
254 if (parent->subtree_max_hole < subtree_max_hole)
255 parent->subtree_max_hole = subtree_max_hole;
256 if (start < HOLE_ADDR(parent))
257 link = &parent->rb_hole_addr.rb_left;
258 else
259 link = &parent->rb_hole_addr.rb_right;
260 }
261
262 rb_link_node(&node->rb_hole_addr, rb_parent, link);
263 rb_insert_augmented(&node->rb_hole_addr, root, &augment_callbacks);
264}
265
266static void add_hole(struct drm_mm_node *node)
267{
268 struct drm_mm *mm = node->mm;
269
270 node->hole_size =
271 __drm_mm_hole_node_end(node) - __drm_mm_hole_node_start(node);
272 node->subtree_max_hole = node->hole_size;
273 DRM_MM_BUG_ON(!drm_mm_hole_follows(node));
274
275 insert_hole_size(&mm->holes_size, node);
276 insert_hole_addr(&mm->holes_addr, node);
277
278 list_add(&node->hole_stack, &mm->hole_stack);
279}
280
281static void rm_hole(struct drm_mm_node *node)
282{
283 DRM_MM_BUG_ON(!drm_mm_hole_follows(node));
284
285 list_del(&node->hole_stack);
286 rb_erase_cached(&node->rb_hole_size, &node->mm->holes_size);
287 rb_erase_augmented(&node->rb_hole_addr, &node->mm->holes_addr,
288 &augment_callbacks);
289 node->hole_size = 0;
290 node->subtree_max_hole = 0;
291
292 DRM_MM_BUG_ON(drm_mm_hole_follows(node));
293}
294
295static inline struct drm_mm_node *rb_hole_size_to_node(struct rb_node *rb)
296{
297 return rb_entry_safe(rb, struct drm_mm_node, rb_hole_size);
298}
299
300static inline struct drm_mm_node *rb_hole_addr_to_node(struct rb_node *rb)
301{
302 return rb_entry_safe(rb, struct drm_mm_node, rb_hole_addr);
303}
304
305static struct drm_mm_node *best_hole(struct drm_mm *mm, u64 size)
306{
307 struct rb_node *rb = mm->holes_size.rb_root.rb_node;
308 struct drm_mm_node *best = NULL;
309
310 do {
311 struct drm_mm_node *node =
312 rb_entry(rb, struct drm_mm_node, rb_hole_size);
313
314 if (size <= node->hole_size) {
315 best = node;
316 rb = rb->rb_right;
317 } else {
318 rb = rb->rb_left;
319 }
320 } while (rb);
321
322 return best;
323}
324
325static bool usable_hole_addr(struct rb_node *rb, u64 size)
326{
327 return rb && rb_hole_addr_to_node(rb)->subtree_max_hole >= size;
328}
329
330static struct drm_mm_node *find_hole_addr(struct drm_mm *mm, u64 addr, u64 size)
331{
332 struct rb_node *rb = mm->holes_addr.rb_node;
333 struct drm_mm_node *node = NULL;
334
335 while (rb) {
336 u64 hole_start;
337
338 if (!usable_hole_addr(rb, size))
339 break;
340
341 node = rb_hole_addr_to_node(rb);
342 hole_start = __drm_mm_hole_node_start(node);
343
344 if (addr < hole_start)
345 rb = node->rb_hole_addr.rb_left;
346 else if (addr > hole_start + node->hole_size)
347 rb = node->rb_hole_addr.rb_right;
348 else
349 break;
350 }
351
352 return node;
353}
354
355static struct drm_mm_node *
356first_hole(struct drm_mm *mm,
357 u64 start, u64 end, u64 size,
358 enum drm_mm_insert_mode mode)
359{
360 switch (mode) {
361 default:
362 case DRM_MM_INSERT_BEST:
363 return best_hole(mm, size);
364
365 case DRM_MM_INSERT_LOW:
366 return find_hole_addr(mm, start, size);
367
368 case DRM_MM_INSERT_HIGH:
369 return find_hole_addr(mm, end, size);
370
371 case DRM_MM_INSERT_EVICT:
372 return list_first_entry_or_null(&mm->hole_stack,
373 struct drm_mm_node,
374 hole_stack);
375 }
376}
377
378/**
379 * DECLARE_NEXT_HOLE_ADDR - macro to declare next hole functions
380 * @name: name of function to declare
381 * @first: first rb member to traverse (either rb_left or rb_right).
382 * @last: last rb member to traverse (either rb_right or rb_left).
383 *
384 * This macro declares a function to return the next hole of the addr rb tree.
385 * While traversing the tree we take the searched size into account and only
386 * visit branches with potential big enough holes.
387 */
388
389#define DECLARE_NEXT_HOLE_ADDR(name, first, last) \
390static struct drm_mm_node *name(struct drm_mm_node *entry, u64 size) \
391{ \
392 struct rb_node *parent, *node = &entry->rb_hole_addr; \
393 \
394 if (!entry || RB_EMPTY_NODE(node)) \
395 return NULL; \
396 \
397 if (usable_hole_addr(node->first, size)) { \
398 node = node->first; \
399 while (usable_hole_addr(node->last, size)) \
400 node = node->last; \
401 return rb_hole_addr_to_node(node); \
402 } \
403 \
404 while ((parent = rb_parent(node)) && node == parent->first) \
405 node = parent; \
406 \
407 return rb_hole_addr_to_node(parent); \
408}
409
410DECLARE_NEXT_HOLE_ADDR(next_hole_high_addr, rb_left, rb_right)
411DECLARE_NEXT_HOLE_ADDR(next_hole_low_addr, rb_right, rb_left)
412
413static struct drm_mm_node *
414next_hole(struct drm_mm *mm,
415 struct drm_mm_node *node,
416 u64 size,
417 enum drm_mm_insert_mode mode)
418{
419 switch (mode) {
420 default:
421 case DRM_MM_INSERT_BEST:
422 return rb_hole_size_to_node(rb_prev(&node->rb_hole_size));
423
424 case DRM_MM_INSERT_LOW:
425 return next_hole_low_addr(node, size);
426
427 case DRM_MM_INSERT_HIGH:
428 return next_hole_high_addr(node, size);
429
430 case DRM_MM_INSERT_EVICT:
431 node = list_next_entry(node, hole_stack);
432 return &node->hole_stack == &mm->hole_stack ? NULL : node;
433 }
434}
435
436/**
437 * drm_mm_reserve_node - insert an pre-initialized node
438 * @mm: drm_mm allocator to insert @node into
439 * @node: drm_mm_node to insert
440 *
441 * This functions inserts an already set-up &drm_mm_node into the allocator,
442 * meaning that start, size and color must be set by the caller. All other
443 * fields must be cleared to 0. This is useful to initialize the allocator with
444 * preallocated objects which must be set-up before the range allocator can be
445 * set-up, e.g. when taking over a firmware framebuffer.
446 *
447 * Returns:
448 * 0 on success, -ENOSPC if there's no hole where @node is.
449 */
450int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node)
451{
452 struct drm_mm_node *hole;
453 u64 hole_start, hole_end;
454 u64 adj_start, adj_end;
455 u64 end;
456
457 end = node->start + node->size;
458 if (unlikely(end <= node->start))
459 return -ENOSPC;
460
461 /* Find the relevant hole to add our node to */
462 hole = find_hole_addr(mm, node->start, 0);
463 if (!hole)
464 return -ENOSPC;
465
466 adj_start = hole_start = __drm_mm_hole_node_start(hole);
467 adj_end = hole_end = hole_start + hole->hole_size;
468
469 if (mm->color_adjust)
470 mm->color_adjust(hole, node->color, &adj_start, &adj_end);
471
472 if (adj_start > node->start || adj_end < end)
473 return -ENOSPC;
474
475 node->mm = mm;
476
477 __set_bit(DRM_MM_NODE_ALLOCATED_BIT, &node->flags);
478 list_add(&node->node_list, &hole->node_list);
479 drm_mm_interval_tree_add_node(hole, node);
480 node->hole_size = 0;
481
482 rm_hole(hole);
483 if (node->start > hole_start)
484 add_hole(hole);
485 if (end < hole_end)
486 add_hole(node);
487
488 save_stack(node);
489 return 0;
490}
491EXPORT_SYMBOL(drm_mm_reserve_node);
492
493static u64 rb_to_hole_size_or_zero(struct rb_node *rb)
494{
495 return rb ? rb_to_hole_size(rb) : 0;
496}
497
498/**
499 * drm_mm_insert_node_in_range - ranged search for space and insert @node
500 * @mm: drm_mm to allocate from
501 * @node: preallocate node to insert
502 * @size: size of the allocation
503 * @alignment: alignment of the allocation
504 * @color: opaque tag value to use for this node
505 * @range_start: start of the allowed range for this node
506 * @range_end: end of the allowed range for this node
507 * @mode: fine-tune the allocation search and placement
508 *
509 * The preallocated @node must be cleared to 0.
510 *
511 * Returns:
512 * 0 on success, -ENOSPC if there's no suitable hole.
513 */
514int drm_mm_insert_node_in_range(struct drm_mm * const mm,
515 struct drm_mm_node * const node,
516 u64 size, u64 alignment,
517 unsigned long color,
518 u64 range_start, u64 range_end,
519 enum drm_mm_insert_mode mode)
520{
521 struct drm_mm_node *hole;
522 u64 remainder_mask;
523 bool once;
524
525 DRM_MM_BUG_ON(range_start > range_end);
526
527 if (unlikely(size == 0 || range_end - range_start < size))
528 return -ENOSPC;
529
530 if (rb_to_hole_size_or_zero(rb_first_cached(&mm->holes_size)) < size)
531 return -ENOSPC;
532
533 if (alignment <= 1)
534 alignment = 0;
535
536 once = mode & DRM_MM_INSERT_ONCE;
537 mode &= ~DRM_MM_INSERT_ONCE;
538
539 remainder_mask = is_power_of_2(alignment) ? alignment - 1 : 0;
540 for (hole = first_hole(mm, range_start, range_end, size, mode);
541 hole;
542 hole = once ? NULL : next_hole(mm, hole, size, mode)) {
543 u64 hole_start = __drm_mm_hole_node_start(hole);
544 u64 hole_end = hole_start + hole->hole_size;
545 u64 adj_start, adj_end;
546 u64 col_start, col_end;
547
548 if (mode == DRM_MM_INSERT_LOW && hole_start >= range_end)
549 break;
550
551 if (mode == DRM_MM_INSERT_HIGH && hole_end <= range_start)
552 break;
553
554 col_start = hole_start;
555 col_end = hole_end;
556 if (mm->color_adjust)
557 mm->color_adjust(hole, color, &col_start, &col_end);
558
559 adj_start = max(col_start, range_start);
560 adj_end = min(col_end, range_end);
561
562 if (adj_end <= adj_start || adj_end - adj_start < size)
563 continue;
564
565 if (mode == DRM_MM_INSERT_HIGH)
566 adj_start = adj_end - size;
567
568 if (alignment) {
569 u64 rem;
570
571 if (likely(remainder_mask))
572 rem = adj_start & remainder_mask;
573 else
574 div64_u64_rem(adj_start, alignment, &rem);
575 if (rem) {
576 adj_start -= rem;
577 if (mode != DRM_MM_INSERT_HIGH)
578 adj_start += alignment;
579
580 if (adj_start < max(col_start, range_start) ||
581 min(col_end, range_end) - adj_start < size)
582 continue;
583
584 if (adj_end <= adj_start ||
585 adj_end - adj_start < size)
586 continue;
587 }
588 }
589
590 node->mm = mm;
591 node->size = size;
592 node->start = adj_start;
593 node->color = color;
594 node->hole_size = 0;
595
596 __set_bit(DRM_MM_NODE_ALLOCATED_BIT, &node->flags);
597 list_add(&node->node_list, &hole->node_list);
598 drm_mm_interval_tree_add_node(hole, node);
599
600 rm_hole(hole);
601 if (adj_start > hole_start)
602 add_hole(hole);
603 if (adj_start + size < hole_end)
604 add_hole(node);
605
606 save_stack(node);
607 return 0;
608 }
609
610 return -ENOSPC;
611}
612EXPORT_SYMBOL(drm_mm_insert_node_in_range);
613
614static inline bool drm_mm_node_scanned_block(const struct drm_mm_node *node)
615{
616 return test_bit(DRM_MM_NODE_SCANNED_BIT, &node->flags);
617}
618
619/**
620 * drm_mm_remove_node - Remove a memory node from the allocator.
621 * @node: drm_mm_node to remove
622 *
623 * This just removes a node from its drm_mm allocator. The node does not need to
624 * be cleared again before it can be re-inserted into this or any other drm_mm
625 * allocator. It is a bug to call this function on a unallocated node.
626 */
627void drm_mm_remove_node(struct drm_mm_node *node)
628{
629 struct drm_mm *mm = node->mm;
630 struct drm_mm_node *prev_node;
631
632 DRM_MM_BUG_ON(!drm_mm_node_allocated(node));
633 DRM_MM_BUG_ON(drm_mm_node_scanned_block(node));
634
635 prev_node = list_prev_entry(node, node_list);
636
637 if (drm_mm_hole_follows(node))
638 rm_hole(node);
639
640 drm_mm_interval_tree_remove(node, &mm->interval_tree);
641 list_del(&node->node_list);
642
643 if (drm_mm_hole_follows(prev_node))
644 rm_hole(prev_node);
645 add_hole(prev_node);
646
647 clear_bit_unlock(DRM_MM_NODE_ALLOCATED_BIT, &node->flags);
648}
649EXPORT_SYMBOL(drm_mm_remove_node);
650
651/**
652 * drm_mm_replace_node - move an allocation from @old to @new
653 * @old: drm_mm_node to remove from the allocator
654 * @new: drm_mm_node which should inherit @old's allocation
655 *
656 * This is useful for when drivers embed the drm_mm_node structure and hence
657 * can't move allocations by reassigning pointers. It's a combination of remove
658 * and insert with the guarantee that the allocation start will match.
659 */
660void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new)
661{
662 struct drm_mm *mm = old->mm;
663
664 DRM_MM_BUG_ON(!drm_mm_node_allocated(old));
665
666 *new = *old;
667
668 __set_bit(DRM_MM_NODE_ALLOCATED_BIT, &new->flags);
669 list_replace(&old->node_list, &new->node_list);
670 rb_replace_node_cached(&old->rb, &new->rb, &mm->interval_tree);
671
672 if (drm_mm_hole_follows(old)) {
673 list_replace(&old->hole_stack, &new->hole_stack);
674 rb_replace_node_cached(&old->rb_hole_size,
675 &new->rb_hole_size,
676 &mm->holes_size);
677 rb_replace_node(&old->rb_hole_addr,
678 &new->rb_hole_addr,
679 &mm->holes_addr);
680 }
681
682 clear_bit_unlock(DRM_MM_NODE_ALLOCATED_BIT, &old->flags);
683}
684EXPORT_SYMBOL(drm_mm_replace_node);
685
686/**
687 * DOC: lru scan roster
688 *
689 * Very often GPUs need to have continuous allocations for a given object. When
690 * evicting objects to make space for a new one it is therefore not most
691 * efficient when we simply start to select all objects from the tail of an LRU
692 * until there's a suitable hole: Especially for big objects or nodes that
693 * otherwise have special allocation constraints there's a good chance we evict
694 * lots of (smaller) objects unnecessarily.
695 *
696 * The DRM range allocator supports this use-case through the scanning
697 * interfaces. First a scan operation needs to be initialized with
698 * drm_mm_scan_init() or drm_mm_scan_init_with_range(). The driver adds
699 * objects to the roster, probably by walking an LRU list, but this can be
700 * freely implemented. Eviction candidates are added using
701 * drm_mm_scan_add_block() until a suitable hole is found or there are no
702 * further evictable objects. Eviction roster metadata is tracked in &struct
703 * drm_mm_scan.
704 *
705 * The driver must walk through all objects again in exactly the reverse
706 * order to restore the allocator state. Note that while the allocator is used
707 * in the scan mode no other operation is allowed.
708 *
709 * Finally the driver evicts all objects selected (drm_mm_scan_remove_block()
710 * reported true) in the scan, and any overlapping nodes after color adjustment
711 * (drm_mm_scan_color_evict()). Adding and removing an object is O(1), and
712 * since freeing a node is also O(1) the overall complexity is
713 * O(scanned_objects). So like the free stack which needs to be walked before a
714 * scan operation even begins this is linear in the number of objects. It
715 * doesn't seem to hurt too badly.
716 */
717
718/**
719 * drm_mm_scan_init_with_range - initialize range-restricted lru scanning
720 * @scan: scan state
721 * @mm: drm_mm to scan
722 * @size: size of the allocation
723 * @alignment: alignment of the allocation
724 * @color: opaque tag value to use for the allocation
725 * @start: start of the allowed range for the allocation
726 * @end: end of the allowed range for the allocation
727 * @mode: fine-tune the allocation search and placement
728 *
729 * This simply sets up the scanning routines with the parameters for the desired
730 * hole.
731 *
732 * Warning:
733 * As long as the scan list is non-empty, no other operations than
734 * adding/removing nodes to/from the scan list are allowed.
735 */
736void drm_mm_scan_init_with_range(struct drm_mm_scan *scan,
737 struct drm_mm *mm,
738 u64 size,
739 u64 alignment,
740 unsigned long color,
741 u64 start,
742 u64 end,
743 enum drm_mm_insert_mode mode)
744{
745 DRM_MM_BUG_ON(start >= end);
746 DRM_MM_BUG_ON(!size || size > end - start);
747 DRM_MM_BUG_ON(mm->scan_active);
748
749 scan->mm = mm;
750
751 if (alignment <= 1)
752 alignment = 0;
753
754 scan->color = color;
755 scan->alignment = alignment;
756 scan->remainder_mask = is_power_of_2(alignment) ? alignment - 1 : 0;
757 scan->size = size;
758 scan->mode = mode;
759
760 DRM_MM_BUG_ON(end <= start);
761 scan->range_start = start;
762 scan->range_end = end;
763
764 scan->hit_start = U64_MAX;
765 scan->hit_end = 0;
766}
767EXPORT_SYMBOL(drm_mm_scan_init_with_range);
768
769/**
770 * drm_mm_scan_add_block - add a node to the scan list
771 * @scan: the active drm_mm scanner
772 * @node: drm_mm_node to add
773 *
774 * Add a node to the scan list that might be freed to make space for the desired
775 * hole.
776 *
777 * Returns:
778 * True if a hole has been found, false otherwise.
779 */
780bool drm_mm_scan_add_block(struct drm_mm_scan *scan,
781 struct drm_mm_node *node)
782{
783 struct drm_mm *mm = scan->mm;
784 struct drm_mm_node *hole;
785 u64 hole_start, hole_end;
786 u64 col_start, col_end;
787 u64 adj_start, adj_end;
788
789 DRM_MM_BUG_ON(node->mm != mm);
790 DRM_MM_BUG_ON(!drm_mm_node_allocated(node));
791 DRM_MM_BUG_ON(drm_mm_node_scanned_block(node));
792 __set_bit(DRM_MM_NODE_SCANNED_BIT, &node->flags);
793 mm->scan_active++;
794
795 /* Remove this block from the node_list so that we enlarge the hole
796 * (distance between the end of our previous node and the start of
797 * or next), without poisoning the link so that we can restore it
798 * later in drm_mm_scan_remove_block().
799 */
800 hole = list_prev_entry(node, node_list);
801 DRM_MM_BUG_ON(list_next_entry(hole, node_list) != node);
802 __list_del_entry(&node->node_list);
803
804 hole_start = __drm_mm_hole_node_start(hole);
805 hole_end = __drm_mm_hole_node_end(hole);
806
807 col_start = hole_start;
808 col_end = hole_end;
809 if (mm->color_adjust)
810 mm->color_adjust(hole, scan->color, &col_start, &col_end);
811
812 adj_start = max(col_start, scan->range_start);
813 adj_end = min(col_end, scan->range_end);
814 if (adj_end <= adj_start || adj_end - adj_start < scan->size)
815 return false;
816
817 if (scan->mode == DRM_MM_INSERT_HIGH)
818 adj_start = adj_end - scan->size;
819
820 if (scan->alignment) {
821 u64 rem;
822
823 if (likely(scan->remainder_mask))
824 rem = adj_start & scan->remainder_mask;
825 else
826 div64_u64_rem(adj_start, scan->alignment, &rem);
827 if (rem) {
828 adj_start -= rem;
829 if (scan->mode != DRM_MM_INSERT_HIGH)
830 adj_start += scan->alignment;
831 if (adj_start < max(col_start, scan->range_start) ||
832 min(col_end, scan->range_end) - adj_start < scan->size)
833 return false;
834
835 if (adj_end <= adj_start ||
836 adj_end - adj_start < scan->size)
837 return false;
838 }
839 }
840
841 scan->hit_start = adj_start;
842 scan->hit_end = adj_start + scan->size;
843
844 DRM_MM_BUG_ON(scan->hit_start >= scan->hit_end);
845 DRM_MM_BUG_ON(scan->hit_start < hole_start);
846 DRM_MM_BUG_ON(scan->hit_end > hole_end);
847
848 return true;
849}
850EXPORT_SYMBOL(drm_mm_scan_add_block);
851
852/**
853 * drm_mm_scan_remove_block - remove a node from the scan list
854 * @scan: the active drm_mm scanner
855 * @node: drm_mm_node to remove
856 *
857 * Nodes **must** be removed in exactly the reverse order from the scan list as
858 * they have been added (e.g. using list_add() as they are added and then
859 * list_for_each() over that eviction list to remove), otherwise the internal
860 * state of the memory manager will be corrupted.
861 *
862 * When the scan list is empty, the selected memory nodes can be freed. An
863 * immediately following drm_mm_insert_node_in_range_generic() or one of the
864 * simpler versions of that function with !DRM_MM_SEARCH_BEST will then return
865 * the just freed block (because it's at the top of the free_stack list).
866 *
867 * Returns:
868 * True if this block should be evicted, false otherwise. Will always
869 * return false when no hole has been found.
870 */
871bool drm_mm_scan_remove_block(struct drm_mm_scan *scan,
872 struct drm_mm_node *node)
873{
874 struct drm_mm_node *prev_node;
875
876 DRM_MM_BUG_ON(node->mm != scan->mm);
877 DRM_MM_BUG_ON(!drm_mm_node_scanned_block(node));
878 __clear_bit(DRM_MM_NODE_SCANNED_BIT, &node->flags);
879
880 DRM_MM_BUG_ON(!node->mm->scan_active);
881 node->mm->scan_active--;
882
883 /* During drm_mm_scan_add_block() we decoupled this node leaving
884 * its pointers intact. Now that the caller is walking back along
885 * the eviction list we can restore this block into its rightful
886 * place on the full node_list. To confirm that the caller is walking
887 * backwards correctly we check that prev_node->next == node->next,
888 * i.e. both believe the same node should be on the other side of the
889 * hole.
890 */
891 prev_node = list_prev_entry(node, node_list);
892 DRM_MM_BUG_ON(list_next_entry(prev_node, node_list) !=
893 list_next_entry(node, node_list));
894 list_add(&node->node_list, &prev_node->node_list);
895
896 return (node->start + node->size > scan->hit_start &&
897 node->start < scan->hit_end);
898}
899EXPORT_SYMBOL(drm_mm_scan_remove_block);
900
901/**
902 * drm_mm_scan_color_evict - evict overlapping nodes on either side of hole
903 * @scan: drm_mm scan with target hole
904 *
905 * After completing an eviction scan and removing the selected nodes, we may
906 * need to remove a few more nodes from either side of the target hole if
907 * mm.color_adjust is being used.
908 *
909 * Returns:
910 * A node to evict, or NULL if there are no overlapping nodes.
911 */
912struct drm_mm_node *drm_mm_scan_color_evict(struct drm_mm_scan *scan)
913{
914 struct drm_mm *mm = scan->mm;
915 struct drm_mm_node *hole;
916 u64 hole_start, hole_end;
917
918 DRM_MM_BUG_ON(list_empty(&mm->hole_stack));
919
920 if (!mm->color_adjust)
921 return NULL;
922
923 /*
924 * The hole found during scanning should ideally be the first element
925 * in the hole_stack list, but due to side-effects in the driver it
926 * may not be.
927 */
928 list_for_each_entry(hole, &mm->hole_stack, hole_stack) {
929 hole_start = __drm_mm_hole_node_start(hole);
930 hole_end = hole_start + hole->hole_size;
931
932 if (hole_start <= scan->hit_start &&
933 hole_end >= scan->hit_end)
934 break;
935 }
936
937 /* We should only be called after we found the hole previously */
938 DRM_MM_BUG_ON(&hole->hole_stack == &mm->hole_stack);
939 if (unlikely(&hole->hole_stack == &mm->hole_stack))
940 return NULL;
941
942 DRM_MM_BUG_ON(hole_start > scan->hit_start);
943 DRM_MM_BUG_ON(hole_end < scan->hit_end);
944
945 mm->color_adjust(hole, scan->color, &hole_start, &hole_end);
946 if (hole_start > scan->hit_start)
947 return hole;
948 if (hole_end < scan->hit_end)
949 return list_next_entry(hole, node_list);
950
951 return NULL;
952}
953EXPORT_SYMBOL(drm_mm_scan_color_evict);
954
955/**
956 * drm_mm_init - initialize a drm-mm allocator
957 * @mm: the drm_mm structure to initialize
958 * @start: start of the range managed by @mm
959 * @size: end of the range managed by @mm
960 *
961 * Note that @mm must be cleared to 0 before calling this function.
962 */
963void drm_mm_init(struct drm_mm *mm, u64 start, u64 size)
964{
965 DRM_MM_BUG_ON(start + size <= start);
966
967 mm->color_adjust = NULL;
968
969 INIT_LIST_HEAD(&mm->hole_stack);
970 mm->interval_tree = RB_ROOT_CACHED;
971 mm->holes_size = RB_ROOT_CACHED;
972 mm->holes_addr = RB_ROOT;
973
974 /* Clever trick to avoid a special case in the free hole tracking. */
975 INIT_LIST_HEAD(&mm->head_node.node_list);
976 mm->head_node.flags = 0;
977 mm->head_node.mm = mm;
978 mm->head_node.start = start + size;
979 mm->head_node.size = -size;
980 add_hole(&mm->head_node);
981
982 mm->scan_active = 0;
983
984#ifdef CONFIG_DRM_DEBUG_MM
985 stack_depot_init();
986#endif
987}
988EXPORT_SYMBOL(drm_mm_init);
989
990/**
991 * drm_mm_takedown - clean up a drm_mm allocator
992 * @mm: drm_mm allocator to clean up
993 *
994 * Note that it is a bug to call this function on an allocator which is not
995 * clean.
996 */
997void drm_mm_takedown(struct drm_mm *mm)
998{
999 if (WARN(!drm_mm_clean(mm),
1000 "Memory manager not clean during takedown.\n"))
1001 show_leaks(mm);
1002}
1003EXPORT_SYMBOL(drm_mm_takedown);
1004
1005static u64 drm_mm_dump_hole(struct drm_printer *p, const struct drm_mm_node *entry)
1006{
1007 u64 start, size;
1008
1009 size = entry->hole_size;
1010 if (size) {
1011 start = drm_mm_hole_node_start(entry);
1012 drm_printf(p, "%#018llx-%#018llx: %llu: free\n",
1013 start, start + size, size);
1014 }
1015
1016 return size;
1017}
1018/**
1019 * drm_mm_print - print allocator state
1020 * @mm: drm_mm allocator to print
1021 * @p: DRM printer to use
1022 */
1023void drm_mm_print(const struct drm_mm *mm, struct drm_printer *p)
1024{
1025 const struct drm_mm_node *entry;
1026 u64 total_used = 0, total_free = 0, total = 0;
1027
1028 total_free += drm_mm_dump_hole(p, &mm->head_node);
1029
1030 drm_mm_for_each_node(entry, mm) {
1031 drm_printf(p, "%#018llx-%#018llx: %llu: used\n", entry->start,
1032 entry->start + entry->size, entry->size);
1033 total_used += entry->size;
1034 total_free += drm_mm_dump_hole(p, entry);
1035 }
1036 total = total_free + total_used;
1037
1038 drm_printf(p, "total: %llu, used %llu free %llu\n", total,
1039 total_used, total_free);
1040}
1041EXPORT_SYMBOL(drm_mm_print);