1 /**************************************************************************
3 * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., USA.
4 * Copyright 2016 Intel Corporation
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:
15 * The above copyright notice and this permission notice (including the
16 * next paragraph) shall be included in all copies or substantial portions
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
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25 * USE OR OTHER DEALINGS IN THE SOFTWARE.
28 **************************************************************************/
31 * Generic simple memory manager implementation. Intended to be used as a base
32 * class implementation for more advanced memory managers.
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.
39 * Aligned allocations can also see improvement.
42 * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
46 #include <drm/drm_mm.h>
47 #include <linux/slab.h>
48 #include <linux/seq_file.h>
49 #include <linux/export.h>
50 #include <linux/interval_tree_generic.h>
55 * drm_mm provides a simple range allocator. The drivers are free to use the
56 * resource allocator from the linux core if it suits them, the upside of drm_mm
57 * is that it's in the DRM core. Which means that it's easier to extend for
58 * some of the crazier special purpose needs of gpus.
60 * The main data struct is &drm_mm, allocations are tracked in &drm_mm_node.
61 * Drivers are free to embed either of them into their own suitable
62 * datastructures. drm_mm itself will not do any memory allocations of its own,
63 * so if drivers choose not to embed nodes they need to still allocate them
66 * The range allocator also supports reservation of preallocated blocks. This is
67 * useful for taking over initial mode setting configurations from the firmware,
68 * where an object needs to be created which exactly matches the firmware's
69 * scanout target. As long as the range is still free it can be inserted anytime
70 * after the allocator is initialized, which helps with avoiding looped
71 * dependencies in the driver load sequence.
73 * drm_mm maintains a stack of most recently freed holes, which of all
74 * simplistic datastructures seems to be a fairly decent approach to clustering
75 * allocations and avoiding too much fragmentation. This means free space
76 * searches are O(num_holes). Given that all the fancy features drm_mm supports
77 * something better would be fairly complex and since gfx thrashing is a fairly
78 * steep cliff not a real concern. Removing a node again is O(1).
80 * drm_mm supports a few features: Alignment and range restrictions can be
81 * supplied. Furthermore every &drm_mm_node has a color value (which is just an
82 * opaque unsigned long) which in conjunction with a driver callback can be used
83 * to implement sophisticated placement restrictions. The i915 DRM driver uses
84 * this to implement guard pages between incompatible caching domains in the
87 * Two behaviors are supported for searching and allocating: bottom-up and
88 * top-down. The default is bottom-up. Top-down allocation can be used if the
89 * memory area has different restrictions, or just to reduce fragmentation.
91 * Finally iteration helpers to walk all nodes and all holes are provided as are
92 * some basic allocator dumpers for debugging.
94 * Note that this range allocator is not thread-safe, drivers need to protect
95 * modifications with their own locking. The idea behind this is that for a full
96 * memory manager additional data needs to be protected anyway, hence internal
97 * locking would be fully redundant.
100 #ifdef CONFIG_DRM_DEBUG_MM
101 #include <linux/stackdepot.h>
103 #define STACKDEPTH 32
106 static noinline void save_stack(struct drm_mm_node *node)
108 unsigned long entries[STACKDEPTH];
111 n = stack_trace_save(entries, ARRAY_SIZE(entries), 1);
113 /* May be called under spinlock, so avoid sleeping */
114 node->stack = stack_depot_save(entries, n, GFP_NOWAIT);
117 static void show_leaks(struct drm_mm *mm)
119 struct drm_mm_node *node;
120 unsigned long *entries;
121 unsigned int nr_entries;
124 buf = kmalloc(BUFSZ, GFP_KERNEL);
128 list_for_each_entry(node, drm_mm_nodes(mm), node_list) {
130 DRM_ERROR("node [%08llx + %08llx]: unknown owner\n",
131 node->start, node->size);
135 nr_entries = stack_depot_fetch(node->stack, &entries);
136 stack_trace_snprint(buf, BUFSZ, entries, nr_entries, 0);
137 DRM_ERROR("node [%08llx + %08llx]: inserted at\n%s",
138 node->start, node->size, buf);
147 static void save_stack(struct drm_mm_node *node) { }
148 static void show_leaks(struct drm_mm *mm) { }
151 #define START(node) ((node)->start)
152 #define LAST(node) ((node)->start + (node)->size - 1)
154 INTERVAL_TREE_DEFINE(struct drm_mm_node, rb,
156 START, LAST, static inline, drm_mm_interval_tree)
159 __drm_mm_interval_first(const struct drm_mm *mm, u64 start, u64 last)
161 return drm_mm_interval_tree_iter_first((struct rb_root_cached *)&mm->interval_tree,
162 start, last) ?: (struct drm_mm_node *)&mm->head_node;
164 EXPORT_SYMBOL(__drm_mm_interval_first);
166 static void drm_mm_interval_tree_add_node(struct drm_mm_node *hole_node,
167 struct drm_mm_node *node)
169 struct drm_mm *mm = hole_node->mm;
170 struct rb_node **link, *rb;
171 struct drm_mm_node *parent;
174 node->__subtree_last = LAST(node);
176 if (hole_node->allocated) {
179 parent = rb_entry(rb, struct drm_mm_node, rb);
180 if (parent->__subtree_last >= node->__subtree_last)
183 parent->__subtree_last = node->__subtree_last;
188 link = &hole_node->rb.rb_right;
192 link = &mm->interval_tree.rb_root.rb_node;
198 parent = rb_entry(rb, struct drm_mm_node, rb);
199 if (parent->__subtree_last < node->__subtree_last)
200 parent->__subtree_last = node->__subtree_last;
201 if (node->start < parent->start) {
202 link = &parent->rb.rb_left;
204 link = &parent->rb.rb_right;
209 rb_link_node(&node->rb, rb, link);
210 rb_insert_augmented_cached(&node->rb, &mm->interval_tree, leftmost,
211 &drm_mm_interval_tree_augment);
214 #define RB_INSERT(root, member, expr) do { \
215 struct rb_node **link = &root.rb_node, *rb = NULL; \
216 u64 x = expr(node); \
219 if (x < expr(rb_entry(rb, struct drm_mm_node, member))) \
220 link = &rb->rb_left; \
222 link = &rb->rb_right; \
224 rb_link_node(&node->member, rb, link); \
225 rb_insert_color(&node->member, &root); \
228 #define HOLE_SIZE(NODE) ((NODE)->hole_size)
229 #define HOLE_ADDR(NODE) (__drm_mm_hole_node_start(NODE))
231 static u64 rb_to_hole_size(struct rb_node *rb)
233 return rb_entry(rb, struct drm_mm_node, rb_hole_size)->hole_size;
236 static void insert_hole_size(struct rb_root_cached *root,
237 struct drm_mm_node *node)
239 struct rb_node **link = &root->rb_root.rb_node, *rb = NULL;
240 u64 x = node->hole_size;
245 if (x > rb_to_hole_size(rb)) {
248 link = &rb->rb_right;
253 rb_link_node(&node->rb_hole_size, rb, link);
254 rb_insert_color_cached(&node->rb_hole_size, root, first);
257 static void add_hole(struct drm_mm_node *node)
259 struct drm_mm *mm = node->mm;
262 __drm_mm_hole_node_end(node) - __drm_mm_hole_node_start(node);
263 DRM_MM_BUG_ON(!drm_mm_hole_follows(node));
265 insert_hole_size(&mm->holes_size, node);
266 RB_INSERT(mm->holes_addr, rb_hole_addr, HOLE_ADDR);
268 list_add(&node->hole_stack, &mm->hole_stack);
271 static void rm_hole(struct drm_mm_node *node)
273 DRM_MM_BUG_ON(!drm_mm_hole_follows(node));
275 list_del(&node->hole_stack);
276 rb_erase_cached(&node->rb_hole_size, &node->mm->holes_size);
277 rb_erase(&node->rb_hole_addr, &node->mm->holes_addr);
280 DRM_MM_BUG_ON(drm_mm_hole_follows(node));
283 static inline struct drm_mm_node *rb_hole_size_to_node(struct rb_node *rb)
285 return rb_entry_safe(rb, struct drm_mm_node, rb_hole_size);
288 static inline struct drm_mm_node *rb_hole_addr_to_node(struct rb_node *rb)
290 return rb_entry_safe(rb, struct drm_mm_node, rb_hole_addr);
293 static inline u64 rb_hole_size(struct rb_node *rb)
295 return rb_entry(rb, struct drm_mm_node, rb_hole_size)->hole_size;
298 static struct drm_mm_node *best_hole(struct drm_mm *mm, u64 size)
300 struct rb_node *rb = mm->holes_size.rb_root.rb_node;
301 struct drm_mm_node *best = NULL;
304 struct drm_mm_node *node =
305 rb_entry(rb, struct drm_mm_node, rb_hole_size);
307 if (size <= node->hole_size) {
318 static struct drm_mm_node *find_hole(struct drm_mm *mm, u64 addr)
320 struct rb_node *rb = mm->holes_addr.rb_node;
321 struct drm_mm_node *node = NULL;
326 node = rb_hole_addr_to_node(rb);
327 hole_start = __drm_mm_hole_node_start(node);
329 if (addr < hole_start)
330 rb = node->rb_hole_addr.rb_left;
331 else if (addr > hole_start + node->hole_size)
332 rb = node->rb_hole_addr.rb_right;
340 static struct drm_mm_node *
341 first_hole(struct drm_mm *mm,
342 u64 start, u64 end, u64 size,
343 enum drm_mm_insert_mode mode)
347 case DRM_MM_INSERT_BEST:
348 return best_hole(mm, size);
350 case DRM_MM_INSERT_LOW:
351 return find_hole(mm, start);
353 case DRM_MM_INSERT_HIGH:
354 return find_hole(mm, end);
356 case DRM_MM_INSERT_EVICT:
357 return list_first_entry_or_null(&mm->hole_stack,
363 static struct drm_mm_node *
364 next_hole(struct drm_mm *mm,
365 struct drm_mm_node *node,
366 enum drm_mm_insert_mode mode)
370 case DRM_MM_INSERT_BEST:
371 return rb_hole_size_to_node(rb_prev(&node->rb_hole_size));
373 case DRM_MM_INSERT_LOW:
374 return rb_hole_addr_to_node(rb_next(&node->rb_hole_addr));
376 case DRM_MM_INSERT_HIGH:
377 return rb_hole_addr_to_node(rb_prev(&node->rb_hole_addr));
379 case DRM_MM_INSERT_EVICT:
380 node = list_next_entry(node, hole_stack);
381 return &node->hole_stack == &mm->hole_stack ? NULL : node;
386 * drm_mm_reserve_node - insert an pre-initialized node
387 * @mm: drm_mm allocator to insert @node into
388 * @node: drm_mm_node to insert
390 * This functions inserts an already set-up &drm_mm_node into the allocator,
391 * meaning that start, size and color must be set by the caller. All other
392 * fields must be cleared to 0. This is useful to initialize the allocator with
393 * preallocated objects which must be set-up before the range allocator can be
394 * set-up, e.g. when taking over a firmware framebuffer.
397 * 0 on success, -ENOSPC if there's no hole where @node is.
399 int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node)
401 u64 end = node->start + node->size;
402 struct drm_mm_node *hole;
403 u64 hole_start, hole_end;
404 u64 adj_start, adj_end;
406 end = node->start + node->size;
407 if (unlikely(end <= node->start))
410 /* Find the relevant hole to add our node to */
411 hole = find_hole(mm, node->start);
415 adj_start = hole_start = __drm_mm_hole_node_start(hole);
416 adj_end = hole_end = hole_start + hole->hole_size;
418 if (mm->color_adjust)
419 mm->color_adjust(hole, node->color, &adj_start, &adj_end);
421 if (adj_start > node->start || adj_end < end)
426 list_add(&node->node_list, &hole->node_list);
427 drm_mm_interval_tree_add_node(hole, node);
428 node->allocated = true;
432 if (node->start > hole_start)
440 EXPORT_SYMBOL(drm_mm_reserve_node);
442 static u64 rb_to_hole_size_or_zero(struct rb_node *rb)
444 return rb ? rb_to_hole_size(rb) : 0;
448 * drm_mm_insert_node_in_range - ranged search for space and insert @node
449 * @mm: drm_mm to allocate from
450 * @node: preallocate node to insert
451 * @size: size of the allocation
452 * @alignment: alignment of the allocation
453 * @color: opaque tag value to use for this node
454 * @range_start: start of the allowed range for this node
455 * @range_end: end of the allowed range for this node
456 * @mode: fine-tune the allocation search and placement
458 * The preallocated @node must be cleared to 0.
461 * 0 on success, -ENOSPC if there's no suitable hole.
463 int drm_mm_insert_node_in_range(struct drm_mm * const mm,
464 struct drm_mm_node * const node,
465 u64 size, u64 alignment,
467 u64 range_start, u64 range_end,
468 enum drm_mm_insert_mode mode)
470 struct drm_mm_node *hole;
474 DRM_MM_BUG_ON(range_start >= range_end);
476 if (unlikely(size == 0 || range_end - range_start < size))
479 if (rb_to_hole_size_or_zero(rb_first_cached(&mm->holes_size)) < size)
485 once = mode & DRM_MM_INSERT_ONCE;
486 mode &= ~DRM_MM_INSERT_ONCE;
488 remainder_mask = is_power_of_2(alignment) ? alignment - 1 : 0;
489 for (hole = first_hole(mm, range_start, range_end, size, mode);
491 hole = once ? NULL : next_hole(mm, hole, mode)) {
492 u64 hole_start = __drm_mm_hole_node_start(hole);
493 u64 hole_end = hole_start + hole->hole_size;
494 u64 adj_start, adj_end;
495 u64 col_start, col_end;
497 if (mode == DRM_MM_INSERT_LOW && hole_start >= range_end)
500 if (mode == DRM_MM_INSERT_HIGH && hole_end <= range_start)
503 col_start = hole_start;
505 if (mm->color_adjust)
506 mm->color_adjust(hole, color, &col_start, &col_end);
508 adj_start = max(col_start, range_start);
509 adj_end = min(col_end, range_end);
511 if (adj_end <= adj_start || adj_end - adj_start < size)
514 if (mode == DRM_MM_INSERT_HIGH)
515 adj_start = adj_end - size;
520 if (likely(remainder_mask))
521 rem = adj_start & remainder_mask;
523 div64_u64_rem(adj_start, alignment, &rem);
526 if (mode != DRM_MM_INSERT_HIGH)
527 adj_start += alignment;
529 if (adj_start < max(col_start, range_start) ||
530 min(col_end, range_end) - adj_start < size)
533 if (adj_end <= adj_start ||
534 adj_end - adj_start < size)
541 node->start = adj_start;
545 list_add(&node->node_list, &hole->node_list);
546 drm_mm_interval_tree_add_node(hole, node);
547 node->allocated = true;
550 if (adj_start > hole_start)
552 if (adj_start + size < hole_end)
561 EXPORT_SYMBOL(drm_mm_insert_node_in_range);
564 * drm_mm_remove_node - Remove a memory node from the allocator.
565 * @node: drm_mm_node to remove
567 * This just removes a node from its drm_mm allocator. The node does not need to
568 * be cleared again before it can be re-inserted into this or any other drm_mm
569 * allocator. It is a bug to call this function on a unallocated node.
571 void drm_mm_remove_node(struct drm_mm_node *node)
573 struct drm_mm *mm = node->mm;
574 struct drm_mm_node *prev_node;
576 DRM_MM_BUG_ON(!node->allocated);
577 DRM_MM_BUG_ON(node->scanned_block);
579 prev_node = list_prev_entry(node, node_list);
581 if (drm_mm_hole_follows(node))
584 drm_mm_interval_tree_remove(node, &mm->interval_tree);
585 list_del(&node->node_list);
586 node->allocated = false;
588 if (drm_mm_hole_follows(prev_node))
592 EXPORT_SYMBOL(drm_mm_remove_node);
595 * drm_mm_replace_node - move an allocation from @old to @new
596 * @old: drm_mm_node to remove from the allocator
597 * @new: drm_mm_node which should inherit @old's allocation
599 * This is useful for when drivers embed the drm_mm_node structure and hence
600 * can't move allocations by reassigning pointers. It's a combination of remove
601 * and insert with the guarantee that the allocation start will match.
603 void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new)
605 struct drm_mm *mm = old->mm;
607 DRM_MM_BUG_ON(!old->allocated);
611 list_replace(&old->node_list, &new->node_list);
612 rb_replace_node_cached(&old->rb, &new->rb, &mm->interval_tree);
614 if (drm_mm_hole_follows(old)) {
615 list_replace(&old->hole_stack, &new->hole_stack);
616 rb_replace_node_cached(&old->rb_hole_size,
619 rb_replace_node(&old->rb_hole_addr,
624 old->allocated = false;
625 new->allocated = true;
627 EXPORT_SYMBOL(drm_mm_replace_node);
630 * DOC: lru scan roster
632 * Very often GPUs need to have continuous allocations for a given object. When
633 * evicting objects to make space for a new one it is therefore not most
634 * efficient when we simply start to select all objects from the tail of an LRU
635 * until there's a suitable hole: Especially for big objects or nodes that
636 * otherwise have special allocation constraints there's a good chance we evict
637 * lots of (smaller) objects unnecessarily.
639 * The DRM range allocator supports this use-case through the scanning
640 * interfaces. First a scan operation needs to be initialized with
641 * drm_mm_scan_init() or drm_mm_scan_init_with_range(). The driver adds
642 * objects to the roster, probably by walking an LRU list, but this can be
643 * freely implemented. Eviction candiates are added using
644 * drm_mm_scan_add_block() until a suitable hole is found or there are no
645 * further evictable objects. Eviction roster metadata is tracked in &struct
648 * The driver must walk through all objects again in exactly the reverse
649 * order to restore the allocator state. Note that while the allocator is used
650 * in the scan mode no other operation is allowed.
652 * Finally the driver evicts all objects selected (drm_mm_scan_remove_block()
653 * reported true) in the scan, and any overlapping nodes after color adjustment
654 * (drm_mm_scan_color_evict()). Adding and removing an object is O(1), and
655 * since freeing a node is also O(1) the overall complexity is
656 * O(scanned_objects). So like the free stack which needs to be walked before a
657 * scan operation even begins this is linear in the number of objects. It
658 * doesn't seem to hurt too badly.
662 * drm_mm_scan_init_with_range - initialize range-restricted lru scanning
664 * @mm: drm_mm to scan
665 * @size: size of the allocation
666 * @alignment: alignment of the allocation
667 * @color: opaque tag value to use for the allocation
668 * @start: start of the allowed range for the allocation
669 * @end: end of the allowed range for the allocation
670 * @mode: fine-tune the allocation search and placement
672 * This simply sets up the scanning routines with the parameters for the desired
676 * As long as the scan list is non-empty, no other operations than
677 * adding/removing nodes to/from the scan list are allowed.
679 void drm_mm_scan_init_with_range(struct drm_mm_scan *scan,
686 enum drm_mm_insert_mode mode)
688 DRM_MM_BUG_ON(start >= end);
689 DRM_MM_BUG_ON(!size || size > end - start);
690 DRM_MM_BUG_ON(mm->scan_active);
698 scan->alignment = alignment;
699 scan->remainder_mask = is_power_of_2(alignment) ? alignment - 1 : 0;
703 DRM_MM_BUG_ON(end <= start);
704 scan->range_start = start;
705 scan->range_end = end;
707 scan->hit_start = U64_MAX;
710 EXPORT_SYMBOL(drm_mm_scan_init_with_range);
713 * drm_mm_scan_add_block - add a node to the scan list
714 * @scan: the active drm_mm scanner
715 * @node: drm_mm_node to add
717 * Add a node to the scan list that might be freed to make space for the desired
721 * True if a hole has been found, false otherwise.
723 bool drm_mm_scan_add_block(struct drm_mm_scan *scan,
724 struct drm_mm_node *node)
726 struct drm_mm *mm = scan->mm;
727 struct drm_mm_node *hole;
728 u64 hole_start, hole_end;
729 u64 col_start, col_end;
730 u64 adj_start, adj_end;
732 DRM_MM_BUG_ON(node->mm != mm);
733 DRM_MM_BUG_ON(!node->allocated);
734 DRM_MM_BUG_ON(node->scanned_block);
735 node->scanned_block = true;
738 /* Remove this block from the node_list so that we enlarge the hole
739 * (distance between the end of our previous node and the start of
740 * or next), without poisoning the link so that we can restore it
741 * later in drm_mm_scan_remove_block().
743 hole = list_prev_entry(node, node_list);
744 DRM_MM_BUG_ON(list_next_entry(hole, node_list) != node);
745 __list_del_entry(&node->node_list);
747 hole_start = __drm_mm_hole_node_start(hole);
748 hole_end = __drm_mm_hole_node_end(hole);
750 col_start = hole_start;
752 if (mm->color_adjust)
753 mm->color_adjust(hole, scan->color, &col_start, &col_end);
755 adj_start = max(col_start, scan->range_start);
756 adj_end = min(col_end, scan->range_end);
757 if (adj_end <= adj_start || adj_end - adj_start < scan->size)
760 if (scan->mode == DRM_MM_INSERT_HIGH)
761 adj_start = adj_end - scan->size;
763 if (scan->alignment) {
766 if (likely(scan->remainder_mask))
767 rem = adj_start & scan->remainder_mask;
769 div64_u64_rem(adj_start, scan->alignment, &rem);
772 if (scan->mode != DRM_MM_INSERT_HIGH)
773 adj_start += scan->alignment;
774 if (adj_start < max(col_start, scan->range_start) ||
775 min(col_end, scan->range_end) - adj_start < scan->size)
778 if (adj_end <= adj_start ||
779 adj_end - adj_start < scan->size)
784 scan->hit_start = adj_start;
785 scan->hit_end = adj_start + scan->size;
787 DRM_MM_BUG_ON(scan->hit_start >= scan->hit_end);
788 DRM_MM_BUG_ON(scan->hit_start < hole_start);
789 DRM_MM_BUG_ON(scan->hit_end > hole_end);
793 EXPORT_SYMBOL(drm_mm_scan_add_block);
796 * drm_mm_scan_remove_block - remove a node from the scan list
797 * @scan: the active drm_mm scanner
798 * @node: drm_mm_node to remove
800 * Nodes **must** be removed in exactly the reverse order from the scan list as
801 * they have been added (e.g. using list_add() as they are added and then
802 * list_for_each() over that eviction list to remove), otherwise the internal
803 * state of the memory manager will be corrupted.
805 * When the scan list is empty, the selected memory nodes can be freed. An
806 * immediately following drm_mm_insert_node_in_range_generic() or one of the
807 * simpler versions of that function with !DRM_MM_SEARCH_BEST will then return
808 * the just freed block (because it's at the top of the free_stack list).
811 * True if this block should be evicted, false otherwise. Will always
812 * return false when no hole has been found.
814 bool drm_mm_scan_remove_block(struct drm_mm_scan *scan,
815 struct drm_mm_node *node)
817 struct drm_mm_node *prev_node;
819 DRM_MM_BUG_ON(node->mm != scan->mm);
820 DRM_MM_BUG_ON(!node->scanned_block);
821 node->scanned_block = false;
823 DRM_MM_BUG_ON(!node->mm->scan_active);
824 node->mm->scan_active--;
826 /* During drm_mm_scan_add_block() we decoupled this node leaving
827 * its pointers intact. Now that the caller is walking back along
828 * the eviction list we can restore this block into its rightful
829 * place on the full node_list. To confirm that the caller is walking
830 * backwards correctly we check that prev_node->next == node->next,
831 * i.e. both believe the same node should be on the other side of the
834 prev_node = list_prev_entry(node, node_list);
835 DRM_MM_BUG_ON(list_next_entry(prev_node, node_list) !=
836 list_next_entry(node, node_list));
837 list_add(&node->node_list, &prev_node->node_list);
839 return (node->start + node->size > scan->hit_start &&
840 node->start < scan->hit_end);
842 EXPORT_SYMBOL(drm_mm_scan_remove_block);
845 * drm_mm_scan_color_evict - evict overlapping nodes on either side of hole
846 * @scan: drm_mm scan with target hole
848 * After completing an eviction scan and removing the selected nodes, we may
849 * need to remove a few more nodes from either side of the target hole if
850 * mm.color_adjust is being used.
853 * A node to evict, or NULL if there are no overlapping nodes.
855 struct drm_mm_node *drm_mm_scan_color_evict(struct drm_mm_scan *scan)
857 struct drm_mm *mm = scan->mm;
858 struct drm_mm_node *hole;
859 u64 hole_start, hole_end;
861 DRM_MM_BUG_ON(list_empty(&mm->hole_stack));
863 if (!mm->color_adjust)
867 * The hole found during scanning should ideally be the first element
868 * in the hole_stack list, but due to side-effects in the driver it
871 list_for_each_entry(hole, &mm->hole_stack, hole_stack) {
872 hole_start = __drm_mm_hole_node_start(hole);
873 hole_end = hole_start + hole->hole_size;
875 if (hole_start <= scan->hit_start &&
876 hole_end >= scan->hit_end)
880 /* We should only be called after we found the hole previously */
881 DRM_MM_BUG_ON(&hole->hole_stack == &mm->hole_stack);
882 if (unlikely(&hole->hole_stack == &mm->hole_stack))
885 DRM_MM_BUG_ON(hole_start > scan->hit_start);
886 DRM_MM_BUG_ON(hole_end < scan->hit_end);
888 mm->color_adjust(hole, scan->color, &hole_start, &hole_end);
889 if (hole_start > scan->hit_start)
891 if (hole_end < scan->hit_end)
892 return list_next_entry(hole, node_list);
896 EXPORT_SYMBOL(drm_mm_scan_color_evict);
899 * drm_mm_init - initialize a drm-mm allocator
900 * @mm: the drm_mm structure to initialize
901 * @start: start of the range managed by @mm
902 * @size: end of the range managed by @mm
904 * Note that @mm must be cleared to 0 before calling this function.
906 void drm_mm_init(struct drm_mm *mm, u64 start, u64 size)
908 DRM_MM_BUG_ON(start + size <= start);
910 mm->color_adjust = NULL;
912 INIT_LIST_HEAD(&mm->hole_stack);
913 mm->interval_tree = RB_ROOT_CACHED;
914 mm->holes_size = RB_ROOT_CACHED;
915 mm->holes_addr = RB_ROOT;
917 /* Clever trick to avoid a special case in the free hole tracking. */
918 INIT_LIST_HEAD(&mm->head_node.node_list);
919 mm->head_node.allocated = false;
920 mm->head_node.mm = mm;
921 mm->head_node.start = start + size;
922 mm->head_node.size = -size;
923 add_hole(&mm->head_node);
927 EXPORT_SYMBOL(drm_mm_init);
930 * drm_mm_takedown - clean up a drm_mm allocator
931 * @mm: drm_mm allocator to clean up
933 * Note that it is a bug to call this function on an allocator which is not
936 void drm_mm_takedown(struct drm_mm *mm)
938 if (WARN(!drm_mm_clean(mm),
939 "Memory manager not clean during takedown.\n"))
942 EXPORT_SYMBOL(drm_mm_takedown);
944 static u64 drm_mm_dump_hole(struct drm_printer *p, const struct drm_mm_node *entry)
948 size = entry->hole_size;
950 start = drm_mm_hole_node_start(entry);
951 drm_printf(p, "%#018llx-%#018llx: %llu: free\n",
952 start, start + size, size);
958 * drm_mm_print - print allocator state
959 * @mm: drm_mm allocator to print
960 * @p: DRM printer to use
962 void drm_mm_print(const struct drm_mm *mm, struct drm_printer *p)
964 const struct drm_mm_node *entry;
965 u64 total_used = 0, total_free = 0, total = 0;
967 total_free += drm_mm_dump_hole(p, &mm->head_node);
969 drm_mm_for_each_node(entry, mm) {
970 drm_printf(p, "%#018llx-%#018llx: %llu: used\n", entry->start,
971 entry->start + entry->size, entry->size);
972 total_used += entry->size;
973 total_free += drm_mm_dump_hole(p, entry);
975 total = total_free + total_used;
977 drm_printf(p, "total: %llu, used %llu free %llu\n", total,
978 total_used, total_free);
980 EXPORT_SYMBOL(drm_mm_print);