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1/**************************************************************************2 *3 * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., USA.4 * Copyright 2016 Intel Corporation5 * All Rights Reserved.6 *7 * Permission is hereby granted, free of charge, to any person obtaining a8 * copy of this software and associated documentation files (the9 * "Software"), to deal in the Software without restriction, including10 * without limitation the rights to use, copy, modify, merge, publish,11 * distribute, sub license, and/or sell copies of the Software, and to12 * permit persons to whom the Software is furnished to do so, subject to13 * the following conditions:14 *15 * The above copyright notice and this permission notice (including the16 * next paragraph) shall be included in all copies or substantial portions17 * of the Software.18 *19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,21 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL22 * 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 OR24 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE25 * USE OR OTHER DEALINGS IN THE SOFTWARE.26 *27 *28 **************************************************************************/29 30/*31 * Generic simple memory manager implementation. Intended to be used as a base32 * class implementation for more advanced memory managers.33 *34 * Note that the algorithm used is quite simple and there might be substantial35 * performance gains if a smarter free list is implemented. Currently it is36 * just an unordered stack of free regions. This could easily be improved if37 * 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: Overview55 *56 * drm_mm provides a simple range allocator. The drivers are free to use the57 * resource allocator from the linux core if it suits them, the upside of drm_mm58 * is that it's in the DRM core. Which means that it's easier to extend for59 * 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 suitable63 * 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 them65 * themselves.66 *67 * The range allocator also supports reservation of preallocated blocks. This is68 * useful for taking over initial mode setting configurations from the firmware,69 * where an object needs to be created which exactly matches the firmware's70 * scanout target. As long as the range is still free it can be inserted anytime71 * after the allocator is initialized, which helps with avoiding looped72 * dependencies in the driver load sequence.73 *74 * drm_mm maintains a stack of most recently freed holes, which of all75 * simplistic datastructures seems to be a fairly decent approach to clustering76 * allocations and avoiding too much fragmentation. This means free space77 * searches are O(num_holes). Given that all the fancy features drm_mm supports78 * something better would be fairly complex and since gfx thrashing is a fairly79 * 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 be82 * supplied. Furthermore every &drm_mm_node has a color value (which is just an83 * opaque unsigned long) which in conjunction with a driver callback can be used84 * to implement sophisticated placement restrictions. The i915 DRM driver uses85 * this to implement guard pages between incompatible caching domains in the86 * graphics TT.87 *88 * Two behaviors are supported for searching and allocating: bottom-up and89 * top-down. The default is bottom-up. Top-down allocation can be used if the90 * 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 are93 * some basic allocator dumpers for debugging.94 *95 * Note that this range allocator is not thread-safe, drivers need to protect96 * modifications with their own locking. The idea behind this is that for a full97 * memory manager additional data needs to be protected anyway, hence internal98 * locking would be fully redundant.99 */100 101#ifdef CONFIG_DRM_DEBUG_MM102#include <linux/stackdepot.h>103 104#define STACKDEPTH 32105#define BUFSZ 4096106 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 STACKDEPTH143#undef BUFSZ144#else145static void save_stack(struct drm_mm_node *node) { }146static void show_leaks(struct drm_mm *mm) { }147#endif148 149#define START(node) ((node)->start)150#define LAST(node) ((node)->start + (node)->size - 1)151 152INTERVAL_TREE_DEFINE(struct drm_mm_node, rb,153 u64, __subtree_last,154 START, LAST, static inline, drm_mm_interval_tree)155 156struct drm_mm_node *157__drm_mm_interval_first(const struct drm_mm *mm, u64 start, u64 last)158{159 return drm_mm_interval_tree_iter_first((struct rb_root_cached *)&mm->interval_tree,160 start, last) ?: (struct drm_mm_node *)&mm->head_node;161}162EXPORT_SYMBOL(__drm_mm_interval_first);163 164static void drm_mm_interval_tree_add_node(struct drm_mm_node *hole_node,165 struct drm_mm_node *node)166{167 struct drm_mm *mm = hole_node->mm;168 struct rb_node **link, *rb;169 struct drm_mm_node *parent;170 bool leftmost;171 172 node->__subtree_last = LAST(node);173 174 if (drm_mm_node_allocated(hole_node)) {175 rb = &hole_node->rb;176 while (rb) {177 parent = rb_entry(rb, struct drm_mm_node, rb);178 if (parent->__subtree_last >= node->__subtree_last)179 break;180 181 parent->__subtree_last = node->__subtree_last;182 rb = rb_parent(rb);183 }184 185 rb = &hole_node->rb;186 link = &hole_node->rb.rb_right;187 leftmost = false;188 } else {189 rb = NULL;190 link = &mm->interval_tree.rb_root.rb_node;191 leftmost = true;192 }193 194 while (*link) {195 rb = *link;196 parent = rb_entry(rb, struct drm_mm_node, rb);197 if (parent->__subtree_last < node->__subtree_last)198 parent->__subtree_last = node->__subtree_last;199 if (node->start < parent->start) {200 link = &parent->rb.rb_left;201 } else {202 link = &parent->rb.rb_right;203 leftmost = false;204 }205 }206 207 rb_link_node(&node->rb, rb, link);208 rb_insert_augmented_cached(&node->rb, &mm->interval_tree, leftmost,209 &drm_mm_interval_tree_augment);210}211 212#define HOLE_SIZE(NODE) ((NODE)->hole_size)213#define HOLE_ADDR(NODE) (__drm_mm_hole_node_start(NODE))214 215static u64 rb_to_hole_size(struct rb_node *rb)216{217 return rb_entry(rb, struct drm_mm_node, rb_hole_size)->hole_size;218}219 220static void insert_hole_size(struct rb_root_cached *root,221 struct drm_mm_node *node)222{223 struct rb_node **link = &root->rb_root.rb_node, *rb = NULL;224 u64 x = node->hole_size;225 bool first = true;226 227 while (*link) {228 rb = *link;229 if (x > rb_to_hole_size(rb)) {230 link = &rb->rb_left;231 } else {232 link = &rb->rb_right;233 first = false;234 }235 }236 237 rb_link_node(&node->rb_hole_size, rb, link);238 rb_insert_color_cached(&node->rb_hole_size, root, first);239}240 241RB_DECLARE_CALLBACKS_MAX(static, augment_callbacks,242 struct drm_mm_node, rb_hole_addr,243 u64, subtree_max_hole, HOLE_SIZE)244 245static void insert_hole_addr(struct rb_root *root, struct drm_mm_node *node)246{247 struct rb_node **link = &root->rb_node, *rb_parent = NULL;248 u64 start = HOLE_ADDR(node), subtree_max_hole = node->subtree_max_hole;249 struct drm_mm_node *parent;250 251 while (*link) {252 rb_parent = *link;253 parent = rb_entry(rb_parent, struct drm_mm_node, rb_hole_addr);254 if (parent->subtree_max_hole < subtree_max_hole)255 parent->subtree_max_hole = subtree_max_hole;256 if (start < HOLE_ADDR(parent))257 link = &parent->rb_hole_addr.rb_left;258 else259 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 else349 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 functions380 * @name: name of function to declare381 * @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 only386 * 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 node438 * @mm: drm_mm allocator to insert @node into439 * @node: drm_mm_node to insert440 *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 other443 * fields must be cleared to 0. This is useful to initialize the allocator with444 * preallocated objects which must be set-up before the range allocator can be445 * 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 @node500 * @mm: drm_mm to allocate from501 * @node: preallocate node to insert502 * @size: size of the allocation503 * @alignment: alignment of the allocation504 * @color: opaque tag value to use for this node505 * @range_start: start of the allowed range for this node506 * @range_end: end of the allowed range for this node507 * @mode: fine-tune the allocation search and placement508 *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 else574 div64_u64_rem(adj_start, alignment, &rem);575 if (rem) {576 adj_start -= rem;577 if (mode != DRM_MM_INSERT_HIGH)578 adj_start += alignment;579 580 if (adj_start < max(col_start, range_start) ||581 min(col_end, range_end) - adj_start < size)582 continue;583 584 if (adj_end <= adj_start ||585 adj_end - adj_start < size)586 continue;587 }588 }589 590 node->mm = mm;591 node->size = size;592 node->start = adj_start;593 node->color = color;594 node->hole_size = 0;595 596 __set_bit(DRM_MM_NODE_ALLOCATED_BIT, &node->flags);597 list_add(&node->node_list, &hole->node_list);598 drm_mm_interval_tree_add_node(hole, node);599 600 rm_hole(hole);601 if (adj_start > hole_start)602 add_hole(hole);603 if (adj_start + size < hole_end)604 add_hole(node);605 606 save_stack(node);607 return 0;608 }609 610 return -ENOSPC;611}612EXPORT_SYMBOL(drm_mm_insert_node_in_range);613 614static inline bool drm_mm_node_scanned_block(const struct drm_mm_node *node)615{616 return test_bit(DRM_MM_NODE_SCANNED_BIT, &node->flags);617}618 619/**620 * drm_mm_remove_node - Remove a memory node from the allocator.621 * @node: drm_mm_node to remove622 *623 * This just removes a node from its drm_mm allocator. The node does not need to624 * be cleared again before it can be re-inserted into this or any other drm_mm625 * 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 roster653 *654 * Very often GPUs need to have continuous allocations for a given object. When655 * evicting objects to make space for a new one it is therefore not most656 * efficient when we simply start to select all objects from the tail of an LRU657 * until there's a suitable hole: Especially for big objects or nodes that658 * otherwise have special allocation constraints there's a good chance we evict659 * lots of (smaller) objects unnecessarily.660 *661 * The DRM range allocator supports this use-case through the scanning662 * interfaces. First a scan operation needs to be initialized with663 * drm_mm_scan_init() or drm_mm_scan_init_with_range(). The driver adds664 * objects to the roster, probably by walking an LRU list, but this can be665 * freely implemented. Eviction candidates are added using666 * drm_mm_scan_add_block() until a suitable hole is found or there are no667 * further evictable objects. Eviction roster metadata is tracked in &struct668 * drm_mm_scan.669 *670 * The driver must walk through all objects again in exactly the reverse671 * order to restore the allocator state. Note that while the allocator is used672 * 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 adjustment676 * (drm_mm_scan_color_evict()). Adding and removing an object is O(1), and677 * since freeing a node is also O(1) the overall complexity is678 * O(scanned_objects). So like the free stack which needs to be walked before a679 * scan operation even begins this is linear in the number of objects. It680 * doesn't seem to hurt too badly.681 */682 683/**684 * drm_mm_scan_init_with_range - initialize range-restricted lru scanning685 * @scan: scan state686 * @mm: drm_mm to scan687 * @size: size of the allocation688 * @alignment: alignment of the allocation689 * @color: opaque tag value to use for the allocation690 * @start: start of the allowed range for the allocation691 * @end: end of the allowed range for the allocation692 * @mode: fine-tune the allocation search and placement693 *694 * This simply sets up the scanning routines with the parameters for the desired695 * hole.696 *697 * Warning:698 * As long as the scan list is non-empty, no other operations than699 * 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 list736 * @scan: the active drm_mm scanner737 * @node: drm_mm_node to add738 *739 * Add a node to the scan list that might be freed to make space for the desired740 * 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 hole761 * (distance between the end of our previous node and the start of762 * or next), without poisoning the link so that we can restore it763 * 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 else791 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 list819 * @scan: the active drm_mm scanner820 * @node: drm_mm_node to remove821 *822 * Nodes **must** be removed in exactly the reverse order from the scan list as823 * they have been added (e.g. using list_add() as they are added and then824 * list_for_each() over that eviction list to remove), otherwise the internal825 * state of the memory manager will be corrupted.826 *827 * When the scan list is empty, the selected memory nodes can be freed. An828 * immediately following drm_mm_insert_node_in_range_generic() or one of the829 * simpler versions of that function with !DRM_MM_SEARCH_BEST will then return830 * 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 always834 * 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 leaving849 * its pointers intact. Now that the caller is walking back along850 * the eviction list we can restore this block into its rightful851 * place on the full node_list. To confirm that the caller is walking852 * 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 the854 * 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 hole868 * @scan: drm_mm scan with target hole869 *870 * After completing an eviction scan and removing the selected nodes, we may871 * need to remove a few more nodes from either side of the target hole if872 * 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 element890 * in the hole_stack list, but due to side-effects in the driver it891 * 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 allocator922 * @mm: the drm_mm structure to initialize923 * @start: start of the range managed by @mm924 * @size: end of the range managed by @mm925 *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_MM950 stack_depot_init();951#endif952}953EXPORT_SYMBOL(drm_mm_init);954 955/**956 * drm_mm_takedown - clean up a drm_mm allocator957 * @mm: drm_mm allocator to clean up958 *959 * Note that it is a bug to call this function on an allocator which is not960 * 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 state985 * @mm: drm_mm allocator to print986 * @p: DRM printer to use987 */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);1007