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