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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 * 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 unsigned long 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 unsigned long size,
100 unsigned alignment,
101 unsigned long color,
102 unsigned long start,
103 unsigned long 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 unsigned long size, unsigned alignment,
109 unsigned long color,
110 enum drm_mm_allocator_flags flags)
111{
112 struct drm_mm *mm = hole_node->mm;
113 unsigned long hole_start = drm_mm_hole_node_start(hole_node);
114 unsigned long hole_end = drm_mm_hole_node_end(hole_node);
115 unsigned long adj_start = hole_start;
116 unsigned long 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 unsigned tmp = adj_start % alignment;
128 if (tmp) {
129 if (flags & DRM_MM_CREATE_TOP)
130 adj_start -= tmp;
131 else
132 adj_start += alignment - tmp;
133 }
134 }
135
136 BUG_ON(adj_start < hole_start);
137 BUG_ON(adj_end > hole_end);
138
139 if (adj_start == hole_start) {
140 hole_node->hole_follows = 0;
141 list_del(&hole_node->hole_stack);
142 }
143
144 node->start = adj_start;
145 node->size = size;
146 node->mm = mm;
147 node->color = color;
148 node->allocated = 1;
149
150 INIT_LIST_HEAD(&node->hole_stack);
151 list_add(&node->node_list, &hole_node->node_list);
152
153 BUG_ON(node->start + node->size > adj_end);
154
155 node->hole_follows = 0;
156 if (__drm_mm_hole_node_start(node) < hole_end) {
157 list_add(&node->hole_stack, &mm->hole_stack);
158 node->hole_follows = 1;
159 }
160}
161
162/**
163 * drm_mm_reserve_node - insert an pre-initialized node
164 * @mm: drm_mm allocator to insert @node into
165 * @node: drm_mm_node to insert
166 *
167 * This functions inserts an already set-up drm_mm_node into the allocator,
168 * meaning that start, size and color must be set by the caller. This is useful
169 * to initialize the allocator with preallocated objects which must be set-up
170 * before the range allocator can be set-up, e.g. when taking over a firmware
171 * framebuffer.
172 *
173 * Returns:
174 * 0 on success, -ENOSPC if there's no hole where @node is.
175 */
176int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node)
177{
178 struct drm_mm_node *hole;
179 unsigned long end = node->start + node->size;
180 unsigned long hole_start;
181 unsigned long hole_end;
182
183 BUG_ON(node == NULL);
184
185 /* Find the relevant hole to add our node to */
186 drm_mm_for_each_hole(hole, mm, hole_start, hole_end) {
187 if (hole_start > node->start || hole_end < end)
188 continue;
189
190 node->mm = mm;
191 node->allocated = 1;
192
193 INIT_LIST_HEAD(&node->hole_stack);
194 list_add(&node->node_list, &hole->node_list);
195
196 if (node->start == hole_start) {
197 hole->hole_follows = 0;
198 list_del_init(&hole->hole_stack);
199 }
200
201 node->hole_follows = 0;
202 if (end != hole_end) {
203 list_add(&node->hole_stack, &mm->hole_stack);
204 node->hole_follows = 1;
205 }
206
207 return 0;
208 }
209
210 return -ENOSPC;
211}
212EXPORT_SYMBOL(drm_mm_reserve_node);
213
214/**
215 * drm_mm_insert_node_generic - search for space and insert @node
216 * @mm: drm_mm to allocate from
217 * @node: preallocate node to insert
218 * @size: size of the allocation
219 * @alignment: alignment of the allocation
220 * @color: opaque tag value to use for this node
221 * @sflags: flags to fine-tune the allocation search
222 * @aflags: flags to fine-tune the allocation behavior
223 *
224 * The preallocated node must be cleared to 0.
225 *
226 * Returns:
227 * 0 on success, -ENOSPC if there's no suitable hole.
228 */
229int drm_mm_insert_node_generic(struct drm_mm *mm, struct drm_mm_node *node,
230 unsigned long size, unsigned alignment,
231 unsigned long color,
232 enum drm_mm_search_flags sflags,
233 enum drm_mm_allocator_flags aflags)
234{
235 struct drm_mm_node *hole_node;
236
237 hole_node = drm_mm_search_free_generic(mm, size, alignment,
238 color, sflags);
239 if (!hole_node)
240 return -ENOSPC;
241
242 drm_mm_insert_helper(hole_node, node, size, alignment, color, aflags);
243 return 0;
244}
245EXPORT_SYMBOL(drm_mm_insert_node_generic);
246
247static void drm_mm_insert_helper_range(struct drm_mm_node *hole_node,
248 struct drm_mm_node *node,
249 unsigned long size, unsigned alignment,
250 unsigned long color,
251 unsigned long start, unsigned long end,
252 enum drm_mm_allocator_flags flags)
253{
254 struct drm_mm *mm = hole_node->mm;
255 unsigned long hole_start = drm_mm_hole_node_start(hole_node);
256 unsigned long hole_end = drm_mm_hole_node_end(hole_node);
257 unsigned long adj_start = hole_start;
258 unsigned long adj_end = hole_end;
259
260 BUG_ON(!hole_node->hole_follows || node->allocated);
261
262 if (adj_start < start)
263 adj_start = start;
264 if (adj_end > end)
265 adj_end = end;
266
267 if (flags & DRM_MM_CREATE_TOP)
268 adj_start = adj_end - size;
269
270 if (mm->color_adjust)
271 mm->color_adjust(hole_node, color, &adj_start, &adj_end);
272
273 if (alignment) {
274 unsigned tmp = adj_start % alignment;
275 if (tmp) {
276 if (flags & DRM_MM_CREATE_TOP)
277 adj_start -= tmp;
278 else
279 adj_start += alignment - tmp;
280 }
281 }
282
283 if (adj_start == hole_start) {
284 hole_node->hole_follows = 0;
285 list_del(&hole_node->hole_stack);
286 }
287
288 node->start = adj_start;
289 node->size = size;
290 node->mm = mm;
291 node->color = color;
292 node->allocated = 1;
293
294 INIT_LIST_HEAD(&node->hole_stack);
295 list_add(&node->node_list, &hole_node->node_list);
296
297 BUG_ON(node->start < start);
298 BUG_ON(node->start < adj_start);
299 BUG_ON(node->start + node->size > adj_end);
300 BUG_ON(node->start + node->size > end);
301
302 node->hole_follows = 0;
303 if (__drm_mm_hole_node_start(node) < hole_end) {
304 list_add(&node->hole_stack, &mm->hole_stack);
305 node->hole_follows = 1;
306 }
307}
308
309/**
310 * drm_mm_insert_node_in_range_generic - ranged search for space and insert @node
311 * @mm: drm_mm to allocate from
312 * @node: preallocate node to insert
313 * @size: size of the allocation
314 * @alignment: alignment of the allocation
315 * @color: opaque tag value to use for this node
316 * @start: start of the allowed range for this node
317 * @end: end of the allowed range for this node
318 * @sflags: flags to fine-tune the allocation search
319 * @aflags: flags to fine-tune the allocation behavior
320 *
321 * The preallocated node must be cleared to 0.
322 *
323 * Returns:
324 * 0 on success, -ENOSPC if there's no suitable hole.
325 */
326int drm_mm_insert_node_in_range_generic(struct drm_mm *mm, struct drm_mm_node *node,
327 unsigned long size, unsigned alignment,
328 unsigned long color,
329 unsigned long start, unsigned long end,
330 enum drm_mm_search_flags sflags,
331 enum drm_mm_allocator_flags aflags)
332{
333 struct drm_mm_node *hole_node;
334
335 hole_node = drm_mm_search_free_in_range_generic(mm,
336 size, alignment, color,
337 start, end, sflags);
338 if (!hole_node)
339 return -ENOSPC;
340
341 drm_mm_insert_helper_range(hole_node, node,
342 size, alignment, color,
343 start, end, aflags);
344 return 0;
345}
346EXPORT_SYMBOL(drm_mm_insert_node_in_range_generic);
347
348/**
349 * drm_mm_remove_node - Remove a memory node from the allocator.
350 * @node: drm_mm_node to remove
351 *
352 * This just removes a node from its drm_mm allocator. The node does not need to
353 * be cleared again before it can be re-inserted into this or any other drm_mm
354 * allocator. It is a bug to call this function on a un-allocated node.
355 */
356void drm_mm_remove_node(struct drm_mm_node *node)
357{
358 struct drm_mm *mm = node->mm;
359 struct drm_mm_node *prev_node;
360
361 if (WARN_ON(!node->allocated))
362 return;
363
364 BUG_ON(node->scanned_block || node->scanned_prev_free
365 || node->scanned_next_free);
366
367 prev_node =
368 list_entry(node->node_list.prev, struct drm_mm_node, node_list);
369
370 if (node->hole_follows) {
371 BUG_ON(__drm_mm_hole_node_start(node) ==
372 __drm_mm_hole_node_end(node));
373 list_del(&node->hole_stack);
374 } else
375 BUG_ON(__drm_mm_hole_node_start(node) !=
376 __drm_mm_hole_node_end(node));
377
378
379 if (!prev_node->hole_follows) {
380 prev_node->hole_follows = 1;
381 list_add(&prev_node->hole_stack, &mm->hole_stack);
382 } else
383 list_move(&prev_node->hole_stack, &mm->hole_stack);
384
385 list_del(&node->node_list);
386 node->allocated = 0;
387}
388EXPORT_SYMBOL(drm_mm_remove_node);
389
390static int check_free_hole(unsigned long start, unsigned long end,
391 unsigned long size, unsigned alignment)
392{
393 if (end - start < size)
394 return 0;
395
396 if (alignment) {
397 unsigned tmp = start % alignment;
398 if (tmp)
399 start += alignment - tmp;
400 }
401
402 return end >= start + size;
403}
404
405static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
406 unsigned long size,
407 unsigned alignment,
408 unsigned long color,
409 enum drm_mm_search_flags flags)
410{
411 struct drm_mm_node *entry;
412 struct drm_mm_node *best;
413 unsigned long adj_start;
414 unsigned long adj_end;
415 unsigned long best_size;
416
417 BUG_ON(mm->scanned_blocks);
418
419 best = NULL;
420 best_size = ~0UL;
421
422 __drm_mm_for_each_hole(entry, mm, adj_start, adj_end,
423 flags & DRM_MM_SEARCH_BELOW) {
424 unsigned long hole_size = adj_end - adj_start;
425
426 if (mm->color_adjust) {
427 mm->color_adjust(entry, color, &adj_start, &adj_end);
428 if (adj_end <= adj_start)
429 continue;
430 }
431
432 if (!check_free_hole(adj_start, adj_end, size, alignment))
433 continue;
434
435 if (!(flags & DRM_MM_SEARCH_BEST))
436 return entry;
437
438 if (hole_size < best_size) {
439 best = entry;
440 best_size = hole_size;
441 }
442 }
443
444 return best;
445}
446
447static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm,
448 unsigned long size,
449 unsigned alignment,
450 unsigned long color,
451 unsigned long start,
452 unsigned long end,
453 enum drm_mm_search_flags flags)
454{
455 struct drm_mm_node *entry;
456 struct drm_mm_node *best;
457 unsigned long adj_start;
458 unsigned long adj_end;
459 unsigned long best_size;
460
461 BUG_ON(mm->scanned_blocks);
462
463 best = NULL;
464 best_size = ~0UL;
465
466 __drm_mm_for_each_hole(entry, mm, adj_start, adj_end,
467 flags & DRM_MM_SEARCH_BELOW) {
468 unsigned long hole_size = adj_end - adj_start;
469
470 if (adj_start < start)
471 adj_start = start;
472 if (adj_end > end)
473 adj_end = end;
474
475 if (mm->color_adjust) {
476 mm->color_adjust(entry, color, &adj_start, &adj_end);
477 if (adj_end <= adj_start)
478 continue;
479 }
480
481 if (!check_free_hole(adj_start, adj_end, size, alignment))
482 continue;
483
484 if (!(flags & DRM_MM_SEARCH_BEST))
485 return entry;
486
487 if (hole_size < best_size) {
488 best = entry;
489 best_size = hole_size;
490 }
491 }
492
493 return best;
494}
495
496/**
497 * drm_mm_replace_node - move an allocation from @old to @new
498 * @old: drm_mm_node to remove from the allocator
499 * @new: drm_mm_node which should inherit @old's allocation
500 *
501 * This is useful for when drivers embed the drm_mm_node structure and hence
502 * can't move allocations by reassigning pointers. It's a combination of remove
503 * and insert with the guarantee that the allocation start will match.
504 */
505void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new)
506{
507 list_replace(&old->node_list, &new->node_list);
508 list_replace(&old->hole_stack, &new->hole_stack);
509 new->hole_follows = old->hole_follows;
510 new->mm = old->mm;
511 new->start = old->start;
512 new->size = old->size;
513 new->color = old->color;
514
515 old->allocated = 0;
516 new->allocated = 1;
517}
518EXPORT_SYMBOL(drm_mm_replace_node);
519
520/**
521 * DOC: lru scan roaster
522 *
523 * Very often GPUs need to have continuous allocations for a given object. When
524 * evicting objects to make space for a new one it is therefore not most
525 * efficient when we simply start to select all objects from the tail of an LRU
526 * until there's a suitable hole: Especially for big objects or nodes that
527 * otherwise have special allocation constraints there's a good chance we evict
528 * lots of (smaller) objects unecessarily.
529 *
530 * The DRM range allocator supports this use-case through the scanning
531 * interfaces. First a scan operation needs to be initialized with
532 * drm_mm_init_scan() or drm_mm_init_scan_with_range(). The the driver adds
533 * objects to the roaster (probably by walking an LRU list, but this can be
534 * freely implemented) until a suitable hole is found or there's no further
535 * evitable object.
536 *
537 * The the driver must walk through all objects again in exactly the reverse
538 * order to restore the allocator state. Note that while the allocator is used
539 * in the scan mode no other operation is allowed.
540 *
541 * Finally the driver evicts all objects selected in the scan. Adding and
542 * removing an object is O(1), and since freeing a node is also O(1) the overall
543 * complexity is O(scanned_objects). So like the free stack which needs to be
544 * walked before a scan operation even begins this is linear in the number of
545 * objects. It doesn't seem to hurt badly.
546 */
547
548/**
549 * drm_mm_init_scan - initialize lru scanning
550 * @mm: drm_mm to scan
551 * @size: size of the allocation
552 * @alignment: alignment of the allocation
553 * @color: opaque tag value to use for the allocation
554 *
555 * This simply sets up the scanning routines with the parameters for the desired
556 * hole. Note that there's no need to specify allocation flags, since they only
557 * change the place a node is allocated from within a suitable hole.
558 *
559 * Warning:
560 * As long as the scan list is non-empty, no other operations than
561 * adding/removing nodes to/from the scan list are allowed.
562 */
563void drm_mm_init_scan(struct drm_mm *mm,
564 unsigned long size,
565 unsigned alignment,
566 unsigned long color)
567{
568 mm->scan_color = color;
569 mm->scan_alignment = alignment;
570 mm->scan_size = size;
571 mm->scanned_blocks = 0;
572 mm->scan_hit_start = 0;
573 mm->scan_hit_end = 0;
574 mm->scan_check_range = 0;
575 mm->prev_scanned_node = NULL;
576}
577EXPORT_SYMBOL(drm_mm_init_scan);
578
579/**
580 * drm_mm_init_scan - initialize range-restricted lru scanning
581 * @mm: drm_mm to scan
582 * @size: size of the allocation
583 * @alignment: alignment of the allocation
584 * @color: opaque tag value to use for the allocation
585 * @start: start of the allowed range for the allocation
586 * @end: end of the allowed range for the allocation
587 *
588 * This simply sets up the scanning routines with the parameters for the desired
589 * hole. Note that there's no need to specify allocation flags, since they only
590 * change the place a node is allocated from within a suitable hole.
591 *
592 * Warning:
593 * As long as the scan list is non-empty, no other operations than
594 * adding/removing nodes to/from the scan list are allowed.
595 */
596void drm_mm_init_scan_with_range(struct drm_mm *mm,
597 unsigned long size,
598 unsigned alignment,
599 unsigned long color,
600 unsigned long start,
601 unsigned long end)
602{
603 mm->scan_color = color;
604 mm->scan_alignment = alignment;
605 mm->scan_size = size;
606 mm->scanned_blocks = 0;
607 mm->scan_hit_start = 0;
608 mm->scan_hit_end = 0;
609 mm->scan_start = start;
610 mm->scan_end = end;
611 mm->scan_check_range = 1;
612 mm->prev_scanned_node = NULL;
613}
614EXPORT_SYMBOL(drm_mm_init_scan_with_range);
615
616/**
617 * drm_mm_scan_add_block - add a node to the scan list
618 * @node: drm_mm_node to add
619 *
620 * Add a node to the scan list that might be freed to make space for the desired
621 * hole.
622 *
623 * Returns:
624 * True if a hole has been found, false otherwise.
625 */
626bool drm_mm_scan_add_block(struct drm_mm_node *node)
627{
628 struct drm_mm *mm = node->mm;
629 struct drm_mm_node *prev_node;
630 unsigned long hole_start, hole_end;
631 unsigned long adj_start, adj_end;
632
633 mm->scanned_blocks++;
634
635 BUG_ON(node->scanned_block);
636 node->scanned_block = 1;
637
638 prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
639 node_list);
640
641 node->scanned_preceeds_hole = prev_node->hole_follows;
642 prev_node->hole_follows = 1;
643 list_del(&node->node_list);
644 node->node_list.prev = &prev_node->node_list;
645 node->node_list.next = &mm->prev_scanned_node->node_list;
646 mm->prev_scanned_node = node;
647
648 adj_start = hole_start = drm_mm_hole_node_start(prev_node);
649 adj_end = hole_end = drm_mm_hole_node_end(prev_node);
650
651 if (mm->scan_check_range) {
652 if (adj_start < mm->scan_start)
653 adj_start = mm->scan_start;
654 if (adj_end > mm->scan_end)
655 adj_end = mm->scan_end;
656 }
657
658 if (mm->color_adjust)
659 mm->color_adjust(prev_node, mm->scan_color,
660 &adj_start, &adj_end);
661
662 if (check_free_hole(adj_start, adj_end,
663 mm->scan_size, mm->scan_alignment)) {
664 mm->scan_hit_start = hole_start;
665 mm->scan_hit_end = hole_end;
666 return true;
667 }
668
669 return false;
670}
671EXPORT_SYMBOL(drm_mm_scan_add_block);
672
673/**
674 * drm_mm_scan_remove_block - remove a node from the scan list
675 * @node: drm_mm_node to remove
676 *
677 * Nodes _must_ be removed in the exact same order from the scan list as they
678 * have been added, otherwise the internal state of the memory manager will be
679 * corrupted.
680 *
681 * When the scan list is empty, the selected memory nodes can be freed. An
682 * immediately following drm_mm_search_free with !DRM_MM_SEARCH_BEST will then
683 * return the just freed block (because its at the top of the free_stack list).
684 *
685 * Returns:
686 * True if this block should be evicted, false otherwise. Will always
687 * return false when no hole has been found.
688 */
689bool drm_mm_scan_remove_block(struct drm_mm_node *node)
690{
691 struct drm_mm *mm = node->mm;
692 struct drm_mm_node *prev_node;
693
694 mm->scanned_blocks--;
695
696 BUG_ON(!node->scanned_block);
697 node->scanned_block = 0;
698
699 prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
700 node_list);
701
702 prev_node->hole_follows = node->scanned_preceeds_hole;
703 list_add(&node->node_list, &prev_node->node_list);
704
705 return (drm_mm_hole_node_end(node) > mm->scan_hit_start &&
706 node->start < mm->scan_hit_end);
707}
708EXPORT_SYMBOL(drm_mm_scan_remove_block);
709
710/**
711 * drm_mm_clean - checks whether an allocator is clean
712 * @mm: drm_mm allocator to check
713 *
714 * Returns:
715 * True if the allocator is completely free, false if there's still a node
716 * allocated in it.
717 */
718bool drm_mm_clean(struct drm_mm * mm)
719{
720 struct list_head *head = &mm->head_node.node_list;
721
722 return (head->next->next == head);
723}
724EXPORT_SYMBOL(drm_mm_clean);
725
726/**
727 * drm_mm_init - initialize a drm-mm allocator
728 * @mm: the drm_mm structure to initialize
729 * @start: start of the range managed by @mm
730 * @size: end of the range managed by @mm
731 *
732 * Note that @mm must be cleared to 0 before calling this function.
733 */
734void drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size)
735{
736 INIT_LIST_HEAD(&mm->hole_stack);
737 mm->scanned_blocks = 0;
738
739 /* Clever trick to avoid a special case in the free hole tracking. */
740 INIT_LIST_HEAD(&mm->head_node.node_list);
741 INIT_LIST_HEAD(&mm->head_node.hole_stack);
742 mm->head_node.hole_follows = 1;
743 mm->head_node.scanned_block = 0;
744 mm->head_node.scanned_prev_free = 0;
745 mm->head_node.scanned_next_free = 0;
746 mm->head_node.mm = mm;
747 mm->head_node.start = start + size;
748 mm->head_node.size = start - mm->head_node.start;
749 list_add_tail(&mm->head_node.hole_stack, &mm->hole_stack);
750
751 mm->color_adjust = NULL;
752}
753EXPORT_SYMBOL(drm_mm_init);
754
755/**
756 * drm_mm_takedown - clean up a drm_mm allocator
757 * @mm: drm_mm allocator to clean up
758 *
759 * Note that it is a bug to call this function on an allocator which is not
760 * clean.
761 */
762void drm_mm_takedown(struct drm_mm * mm)
763{
764 WARN(!list_empty(&mm->head_node.node_list),
765 "Memory manager not clean during takedown.\n");
766}
767EXPORT_SYMBOL(drm_mm_takedown);
768
769static unsigned long drm_mm_debug_hole(struct drm_mm_node *entry,
770 const char *prefix)
771{
772 unsigned long hole_start, hole_end, hole_size;
773
774 if (entry->hole_follows) {
775 hole_start = drm_mm_hole_node_start(entry);
776 hole_end = drm_mm_hole_node_end(entry);
777 hole_size = hole_end - hole_start;
778 printk(KERN_DEBUG "%s 0x%08lx-0x%08lx: %8lu: free\n",
779 prefix, hole_start, hole_end,
780 hole_size);
781 return hole_size;
782 }
783
784 return 0;
785}
786
787/**
788 * drm_mm_debug_table - dump allocator state to dmesg
789 * @mm: drm_mm allocator to dump
790 * @prefix: prefix to use for dumping to dmesg
791 */
792void drm_mm_debug_table(struct drm_mm *mm, const char *prefix)
793{
794 struct drm_mm_node *entry;
795 unsigned long total_used = 0, total_free = 0, total = 0;
796
797 total_free += drm_mm_debug_hole(&mm->head_node, prefix);
798
799 drm_mm_for_each_node(entry, mm) {
800 printk(KERN_DEBUG "%s 0x%08lx-0x%08lx: %8lu: used\n",
801 prefix, entry->start, entry->start + entry->size,
802 entry->size);
803 total_used += entry->size;
804 total_free += drm_mm_debug_hole(entry, prefix);
805 }
806 total = total_free + total_used;
807
808 printk(KERN_DEBUG "%s total: %lu, used %lu free %lu\n", prefix, total,
809 total_used, total_free);
810}
811EXPORT_SYMBOL(drm_mm_debug_table);
812
813#if defined(CONFIG_DEBUG_FS)
814static unsigned long drm_mm_dump_hole(struct seq_file *m, struct drm_mm_node *entry)
815{
816 unsigned long hole_start, hole_end, hole_size;
817
818 if (entry->hole_follows) {
819 hole_start = drm_mm_hole_node_start(entry);
820 hole_end = drm_mm_hole_node_end(entry);
821 hole_size = hole_end - hole_start;
822 seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: free\n",
823 hole_start, hole_end, hole_size);
824 return hole_size;
825 }
826
827 return 0;
828}
829
830/**
831 * drm_mm_dump_table - dump allocator state to a seq_file
832 * @m: seq_file to dump to
833 * @mm: drm_mm allocator to dump
834 */
835int drm_mm_dump_table(struct seq_file *m, struct drm_mm *mm)
836{
837 struct drm_mm_node *entry;
838 unsigned long total_used = 0, total_free = 0, total = 0;
839
840 total_free += drm_mm_dump_hole(m, &mm->head_node);
841
842 drm_mm_for_each_node(entry, mm) {
843 seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: used\n",
844 entry->start, entry->start + entry->size,
845 entry->size);
846 total_used += entry->size;
847 total_free += drm_mm_dump_hole(m, entry);
848 }
849 total = total_free + total_used;
850
851 seq_printf(m, "total: %lu, used %lu free %lu\n", total, total_used, total_free);
852 return 0;
853}
854EXPORT_SYMBOL(drm_mm_dump_table);
855#endif