1/************************************************************************** 2 * 3 * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., USA. 4 * Copyright 2016 Intel Corporation 5 * All Rights Reserved. 6 * 7 * Permission is hereby granted, free of charge, to any person obtaining a 8 * copy of this software and associated documentation files (the 9 * "Software"), to deal in the Software without restriction, including 10 * without limitation the rights to use, copy, modify, merge, publish, 11 * distribute, sub license, and/or sell copies of the Software, and to 12 * permit persons to whom the Software is furnished to do so, subject to 13 * the following conditions: 14 * 15 * The above copyright notice and this permission notice (including the 16 * next paragraph) shall be included in all copies or substantial portions 17 * of the Software. 18 * 19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 21 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL 22 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, 23 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR 24 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE 25 * USE OR OTHER DEALINGS IN THE SOFTWARE. 26 * 27 * 28 **************************************************************************/ 29 30/* 31 * Generic simple memory manager implementation. Intended to be used as a base 32 * class implementation for more advanced memory managers. 33 * 34 * Note that the algorithm used is quite simple and there might be substantial 35 * performance gains if a smarter free list is implemented. Currently it is 36 * just an unordered stack of free regions. This could easily be improved if 37 * an RB-tree is used instead. At least if we expect heavy fragmentation. 38 * 39 * Aligned allocations can also see improvement. 40 * 41 * Authors: 42 * Thomas Hellström <thomas-at-tungstengraphics-dot-com> 43 */ 44 45#include <linux/export.h> 46#include <linux/interval_tree_generic.h> 47#include <linux/seq_file.h> 48#include <linux/slab.h> 49#include <linux/stacktrace.h> 50 51#include <drm/drm_mm.h> 52 53/** 54 * DOC: Overview 55 * 56 * drm_mm provides a simple range allocator. The drivers are free to use the 57 * resource allocator from the linux core if it suits them, the upside of drm_mm 58 * is that it's in the DRM core. Which means that it's easier to extend for 59 * some of the crazier special purpose needs of gpus. 60 * 61 * The main data struct is &drm_mm, allocations are tracked in &drm_mm_node. 62 * Drivers are free to embed either of them into their own suitable 63 * datastructures. drm_mm itself will not do any memory allocations of its own, 64 * so if drivers choose not to embed nodes they need to still allocate them 65 * themselves. 66 * 67 * The range allocator also supports reservation of preallocated blocks. This is 68 * useful for taking over initial mode setting configurations from the firmware, 69 * where an object needs to be created which exactly matches the firmware's 70 * scanout target. As long as the range is still free it can be inserted anytime 71 * after the allocator is initialized, which helps with avoiding looped 72 * dependencies in the driver load sequence. 73 * 74 * drm_mm maintains a stack of most recently freed holes, which of all 75 * simplistic datastructures seems to be a fairly decent approach to clustering 76 * allocations and avoiding too much fragmentation. This means free space 77 * searches are O(num_holes). Given that all the fancy features drm_mm supports 78 * something better would be fairly complex and since gfx thrashing is a fairly 79 * steep cliff not a real concern. Removing a node again is O(1). 80 * 81 * drm_mm supports a few features: Alignment and range restrictions can be 82 * supplied. Furthermore every &drm_mm_node has a color value (which is just an 83 * opaque unsigned long) which in conjunction with a driver callback can be used 84 * to implement sophisticated placement restrictions. The i915 DRM driver uses 85 * this to implement guard pages between incompatible caching domains in the 86 * graphics TT. 87 * 88 * Two behaviors are supported for searching and allocating: bottom-up and 89 * top-down. The default is bottom-up. Top-down allocation can be used if the 90 * memory area has different restrictions, or just to reduce fragmentation. 91 * 92 * Finally iteration helpers to walk all nodes and all holes are provided as are 93 * some basic allocator dumpers for debugging. 94 * 95 * Note that this range allocator is not thread-safe, drivers need to protect 96 * modifications with their own locking. The idea behind this is that for a full 97 * memory manager additional data needs to be protected anyway, hence internal 98 * locking would be fully redundant. 99 */ 100 101#ifdef CONFIG_DRM_DEBUG_MM 102#include <linux/stackdepot.h> 103 104#define STACKDEPTH 32 105#define BUFSZ 4096 106 107static noinline void save_stack(struct drm_mm_node *node) 108{ 109 unsigned long entries[STACKDEPTH]; 110 unsigned int n; 111 112 n = stack_trace_save(entries, ARRAY_SIZE(entries), 1); 113 114 /* May be called under spinlock, so avoid sleeping */ 115 node->stack = stack_depot_save(entries, n, GFP_NOWAIT); 116} 117 118static void show_leaks(struct drm_mm *mm) 119{ 120 struct drm_mm_node *node; 121 char *buf; 122 123 buf = kmalloc(BUFSZ, GFP_KERNEL); 124 if (!buf) 125 return; 126 127 list_for_each_entry(node, drm_mm_nodes(mm), node_list) { 128 if (!node->stack) { 129 DRM_ERROR("node [%08llx + %08llx]: unknown owner\n", 130 node->start, node->size); 131 continue; 132 } 133 134 stack_depot_snprint(node->stack, buf, BUFSZ, 0); 135 DRM_ERROR("node [%08llx + %08llx]: inserted at\n%s", 136 node->start, node->size, buf); 137 } 138 139 kfree(buf); 140} 141 142#undef STACKDEPTH 143#undef BUFSZ 144#else 145static void save_stack(struct drm_mm_node *node) { } 146static void show_leaks(struct drm_mm *mm) { } 147#endif 148 149#define START(node) ((node)->start) 150#define LAST(node) ((node)->start + (node)->size - 1) 151 152INTERVAL_TREE_DEFINE(struct drm_mm_node, rb, 153 u64, __subtree_last, 154 START, LAST, static inline, drm_mm_interval_tree) 155 156struct drm_mm_node * 157__drm_mm_interval_first(const struct drm_mm *mm, u64 start, u64 last) 158{ 159 return drm_mm_interval_tree_iter_first((struct rb_root_cached *)&mm->interval_tree, 160 start, last) ?: (struct drm_mm_node *)&mm->head_node; 161} 162EXPORT_SYMBOL(__drm_mm_interval_first); 163 164static void drm_mm_interval_tree_add_node(struct drm_mm_node *hole_node, 165 struct drm_mm_node *node) 166{ 167 struct drm_mm *mm = hole_node->mm; 168 struct rb_node **link, *rb; 169 struct drm_mm_node *parent; 170 bool leftmost; 171 172 node->__subtree_last = LAST(node); 173 174 if (drm_mm_node_allocated(hole_node)) { 175 rb = &hole_node->rb; 176 while (rb) { 177 parent = rb_entry(rb, struct drm_mm_node, rb); 178 if (parent->__subtree_last >= node->__subtree_last) 179 break; 180 181 parent->__subtree_last = node->__subtree_last; 182 rb = rb_parent(rb); 183 } 184 185 rb = &hole_node->rb; 186 link = &hole_node->rb.rb_right; 187 leftmost = false; 188 } else { 189 rb = NULL; 190 link = &mm->interval_tree.rb_root.rb_node; 191 leftmost = true; 192 } 193 194 while (*link) { 195 rb = *link; 196 parent = rb_entry(rb, struct drm_mm_node, rb); 197 if (parent->__subtree_last < node->__subtree_last) 198 parent->__subtree_last = node->__subtree_last; 199 if (node->start < parent->start) { 200 link = &parent->rb.rb_left; 201 } else { 202 link = &parent->rb.rb_right; 203 leftmost = false; 204 } 205 } 206 207 rb_link_node(&node->rb, rb, link); 208 rb_insert_augmented_cached(&node->rb, &mm->interval_tree, leftmost, 209 &drm_mm_interval_tree_augment); 210} 211 212#define HOLE_SIZE(NODE) ((NODE)->hole_size) 213#define HOLE_ADDR(NODE) (__drm_mm_hole_node_start(NODE)) 214 215static u64 rb_to_hole_size(struct rb_node *rb) 216{ 217 return rb_entry(rb, struct drm_mm_node, rb_hole_size)->hole_size; 218} 219 220static void insert_hole_size(struct rb_root_cached *root, 221 struct drm_mm_node *node) 222{ 223 struct rb_node **link = &root->rb_root.rb_node, *rb = NULL; 224 u64 x = node->hole_size; 225 bool first = true; 226 227 while (*link) { 228 rb = *link; 229 if (x > rb_to_hole_size(rb)) { 230 link = &rb->rb_left; 231 } else { 232 link = &rb->rb_right; 233 first = false; 234 } 235 } 236 237 rb_link_node(&node->rb_hole_size, rb, link); 238 rb_insert_color_cached(&node->rb_hole_size, root, first); 239} 240 241RB_DECLARE_CALLBACKS_MAX(static, augment_callbacks, 242 struct drm_mm_node, rb_hole_addr, 243 u64, subtree_max_hole, HOLE_SIZE) 244 245static void insert_hole_addr(struct rb_root *root, struct drm_mm_node *node) 246{ 247 struct rb_node **link = &root->rb_node, *rb_parent = NULL; 248 u64 start = HOLE_ADDR(node), subtree_max_hole = node->subtree_max_hole; 249 struct drm_mm_node *parent; 250 251 while (*link) { 252 rb_parent = *link; 253 parent = rb_entry(rb_parent, struct drm_mm_node, rb_hole_addr); 254 if (parent->subtree_max_hole < subtree_max_hole) 255 parent->subtree_max_hole = subtree_max_hole; 256 if (start < HOLE_ADDR(parent)) 257 link = &parent->rb_hole_addr.rb_left; 258 else 259 link = &parent->rb_hole_addr.rb_right; 260 } 261 262 rb_link_node(&node->rb_hole_addr, rb_parent, link); 263 rb_insert_augmented(&node->rb_hole_addr, root, &augment_callbacks); 264} 265 266static void add_hole(struct drm_mm_node *node) 267{ 268 struct drm_mm *mm = node->mm; 269 270 node->hole_size = 271 __drm_mm_hole_node_end(node) - __drm_mm_hole_node_start(node); 272 node->subtree_max_hole = node->hole_size; 273 DRM_MM_BUG_ON(!drm_mm_hole_follows(node)); 274 275 insert_hole_size(&mm->holes_size, node); 276 insert_hole_addr(&mm->holes_addr, node); 277 278 list_add(&node->hole_stack, &mm->hole_stack); 279} 280 281static void rm_hole(struct drm_mm_node *node) 282{ 283 DRM_MM_BUG_ON(!drm_mm_hole_follows(node)); 284 285 list_del(&node->hole_stack); 286 rb_erase_cached(&node->rb_hole_size, &node->mm->holes_size); 287 rb_erase_augmented(&node->rb_hole_addr, &node->mm->holes_addr, 288 &augment_callbacks); 289 node->hole_size = 0; 290 node->subtree_max_hole = 0; 291 292 DRM_MM_BUG_ON(drm_mm_hole_follows(node)); 293} 294 295static inline struct drm_mm_node *rb_hole_size_to_node(struct rb_node *rb) 296{ 297 return rb_entry_safe(rb, struct drm_mm_node, rb_hole_size); 298} 299 300static inline struct drm_mm_node *rb_hole_addr_to_node(struct rb_node *rb) 301{ 302 return rb_entry_safe(rb, struct drm_mm_node, rb_hole_addr); 303} 304 305static struct drm_mm_node *best_hole(struct drm_mm *mm, u64 size) 306{ 307 struct rb_node *rb = mm->holes_size.rb_root.rb_node; 308 struct drm_mm_node *best = NULL; 309 310 do { 311 struct drm_mm_node *node = 312 rb_entry(rb, struct drm_mm_node, rb_hole_size); 313 314 if (size <= node->hole_size) { 315 best = node; 316 rb = rb->rb_right; 317 } else { 318 rb = rb->rb_left; 319 } 320 } while (rb); 321 322 return best; 323} 324 325static bool usable_hole_addr(struct rb_node *rb, u64 size) 326{ 327 return rb && rb_hole_addr_to_node(rb)->subtree_max_hole >= size; 328} 329 330static struct drm_mm_node *find_hole_addr(struct drm_mm *mm, u64 addr, u64 size) 331{ 332 struct rb_node *rb = mm->holes_addr.rb_node; 333 struct drm_mm_node *node = NULL; 334 335 while (rb) { 336 u64 hole_start; 337 338 if (!usable_hole_addr(rb, size)) 339 break; 340 341 node = rb_hole_addr_to_node(rb); 342 hole_start = __drm_mm_hole_node_start(node); 343 344 if (addr < hole_start) 345 rb = node->rb_hole_addr.rb_left; 346 else if (addr > hole_start + node->hole_size) 347 rb = node->rb_hole_addr.rb_right; 348 else 349 break; 350 } 351 352 return node; 353} 354 355static struct drm_mm_node * 356first_hole(struct drm_mm *mm, 357 u64 start, u64 end, u64 size, 358 enum drm_mm_insert_mode mode) 359{ 360 switch (mode) { 361 default: 362 case DRM_MM_INSERT_BEST: 363 return best_hole(mm, size); 364 365 case DRM_MM_INSERT_LOW: 366 return find_hole_addr(mm, start, size); 367 368 case DRM_MM_INSERT_HIGH: 369 return find_hole_addr(mm, end, size); 370 371 case DRM_MM_INSERT_EVICT: 372 return list_first_entry_or_null(&mm->hole_stack, 373 struct drm_mm_node, 374 hole_stack); 375 } 376} 377 378/** 379 * DECLARE_NEXT_HOLE_ADDR - macro to declare next hole functions 380 * @name: name of function to declare 381 * @first: first rb member to traverse (either rb_left or rb_right). 382 * @last: last rb member to traverse (either rb_right or rb_left). 383 * 384 * This macro declares a function to return the next hole of the addr rb tree. 385 * While traversing the tree we take the searched size into account and only 386 * visit branches with potential big enough holes. 387 */ 388 389#define DECLARE_NEXT_HOLE_ADDR(name, first, last) \ 390static struct drm_mm_node *name(struct drm_mm_node *entry, u64 size) \ 391{ \ 392 struct rb_node *parent, *node = &entry->rb_hole_addr; \ 393 \ 394 if (!entry || RB_EMPTY_NODE(node)) \ 395 return NULL; \ 396 \ 397 if (usable_hole_addr(node->first, size)) { \ 398 node = node->first; \ 399 while (usable_hole_addr(node->last, size)) \ 400 node = node->last; \ 401 return rb_hole_addr_to_node(node); \ 402 } \ 403 \ 404 while ((parent = rb_parent(node)) && node == parent->first) \ 405 node = parent; \ 406 \ 407 return rb_hole_addr_to_node(parent); \ 408} 409 410DECLARE_NEXT_HOLE_ADDR(next_hole_high_addr, rb_left, rb_right) 411DECLARE_NEXT_HOLE_ADDR(next_hole_low_addr, rb_right, rb_left) 412 413static struct drm_mm_node * 414next_hole(struct drm_mm *mm, 415 struct drm_mm_node *node, 416 u64 size, 417 enum drm_mm_insert_mode mode) 418{ 419 switch (mode) { 420 default: 421 case DRM_MM_INSERT_BEST: 422 return rb_hole_size_to_node(rb_prev(&node->rb_hole_size)); 423 424 case DRM_MM_INSERT_LOW: 425 return next_hole_low_addr(node, size); 426 427 case DRM_MM_INSERT_HIGH: 428 return next_hole_high_addr(node, size); 429 430 case DRM_MM_INSERT_EVICT: 431 node = list_next_entry(node, hole_stack); 432 return &node->hole_stack == &mm->hole_stack ? NULL : node; 433 } 434} 435 436/** 437 * drm_mm_reserve_node - insert an pre-initialized node 438 * @mm: drm_mm allocator to insert @node into 439 * @node: drm_mm_node to insert 440 * 441 * This functions inserts an already set-up &drm_mm_node into the allocator, 442 * meaning that start, size and color must be set by the caller. All other 443 * fields must be cleared to 0. This is useful to initialize the allocator with 444 * preallocated objects which must be set-up before the range allocator can be 445 * set-up, e.g. when taking over a firmware framebuffer. 446 * 447 * Returns: 448 * 0 on success, -ENOSPC if there's no hole where @node is. 449 */ 450int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node) 451{ 452 struct drm_mm_node *hole; 453 u64 hole_start, hole_end; 454 u64 adj_start, adj_end; 455 u64 end; 456 457 end = node->start + node->size; 458 if (unlikely(end <= node->start)) 459 return -ENOSPC; 460 461 /* Find the relevant hole to add our node to */ 462 hole = find_hole_addr(mm, node->start, 0); 463 if (!hole) 464 return -ENOSPC; 465 466 adj_start = hole_start = __drm_mm_hole_node_start(hole); 467 adj_end = hole_end = hole_start + hole->hole_size; 468 469 if (mm->color_adjust) 470 mm->color_adjust(hole, node->color, &adj_start, &adj_end); 471 472 if (adj_start > node->start || adj_end < end) 473 return -ENOSPC; 474 475 node->mm = mm; 476 477 __set_bit(DRM_MM_NODE_ALLOCATED_BIT, &node->flags); 478 list_add(&node->node_list, &hole->node_list); 479 drm_mm_interval_tree_add_node(hole, node); 480 node->hole_size = 0; 481 482 rm_hole(hole); 483 if (node->start > hole_start) 484 add_hole(hole); 485 if (end < hole_end) 486 add_hole(node); 487 488 save_stack(node); 489 return 0; 490} 491EXPORT_SYMBOL(drm_mm_reserve_node); 492 493static u64 rb_to_hole_size_or_zero(struct rb_node *rb) 494{ 495 return rb ? rb_to_hole_size(rb) : 0; 496} 497 498/** 499 * drm_mm_insert_node_in_range - ranged search for space and insert @node 500 * @mm: drm_mm to allocate from 501 * @node: preallocate node to insert 502 * @size: size of the allocation 503 * @alignment: alignment of the allocation 504 * @color: opaque tag value to use for this node 505 * @range_start: start of the allowed range for this node 506 * @range_end: end of the allowed range for this node 507 * @mode: fine-tune the allocation search and placement 508 * 509 * The preallocated @node must be cleared to 0. 510 * 511 * Returns: 512 * 0 on success, -ENOSPC if there's no suitable hole. 513 */ 514int drm_mm_insert_node_in_range(struct drm_mm * const mm, 515 struct drm_mm_node * const node, 516 u64 size, u64 alignment, 517 unsigned long color, 518 u64 range_start, u64 range_end, 519 enum drm_mm_insert_mode mode) 520{ 521 struct drm_mm_node *hole; 522 u64 remainder_mask; 523 bool once; 524 525 DRM_MM_BUG_ON(range_start > range_end); 526 527 if (unlikely(size == 0 || range_end - range_start < size)) 528 return -ENOSPC; 529 530 if (rb_to_hole_size_or_zero(rb_first_cached(&mm->holes_size)) < size) 531 return -ENOSPC; 532 533 if (alignment <= 1) 534 alignment = 0; 535 536 once = mode & DRM_MM_INSERT_ONCE; 537 mode &= ~DRM_MM_INSERT_ONCE; 538 539 remainder_mask = is_power_of_2(alignment) ? alignment - 1 : 0; 540 for (hole = first_hole(mm, range_start, range_end, size, mode); 541 hole; 542 hole = once ? NULL : next_hole(mm, hole, size, mode)) { 543 u64 hole_start = __drm_mm_hole_node_start(hole); 544 u64 hole_end = hole_start + hole->hole_size; 545 u64 adj_start, adj_end; 546 u64 col_start, col_end; 547 548 if (mode == DRM_MM_INSERT_LOW && hole_start >= range_end) 549 break; 550 551 if (mode == DRM_MM_INSERT_HIGH && hole_end <= range_start) 552 break; 553 554 col_start = hole_start; 555 col_end = hole_end; 556 if (mm->color_adjust) 557 mm->color_adjust(hole, color, &col_start, &col_end); 558 559 adj_start = max(col_start, range_start); 560 adj_end = min(col_end, range_end); 561 562 if (adj_end <= adj_start || adj_end - adj_start < size) 563 continue; 564 565 if (mode == DRM_MM_INSERT_HIGH) 566 adj_start = adj_end - size; 567 568 if (alignment) { 569 u64 rem; 570 571 if (likely(remainder_mask)) 572 rem = adj_start & remainder_mask; 573 else 574 div64_u64_rem(adj_start, alignment, &rem); 575 if (rem) { 576 adj_start -= rem; 577 if (mode != DRM_MM_INSERT_HIGH) 578 adj_start += alignment; 579 580 if (adj_start < max(col_start, range_start) || 581 min(col_end, range_end) - adj_start < size) 582 continue; 583 584 if (adj_end <= adj_start || 585 adj_end - adj_start < size) 586 continue; 587 } 588 } 589 590 node->mm = mm; 591 node->size = size; 592 node->start = adj_start; 593 node->color = color; 594 node->hole_size = 0; 595 596 __set_bit(DRM_MM_NODE_ALLOCATED_BIT, &node->flags); 597 list_add(&node->node_list, &hole->node_list); 598 drm_mm_interval_tree_add_node(hole, node); 599 600 rm_hole(hole); 601 if (adj_start > hole_start) 602 add_hole(hole); 603 if (adj_start + size < hole_end) 604 add_hole(node); 605 606 save_stack(node); 607 return 0; 608 } 609 610 return -ENOSPC; 611} 612EXPORT_SYMBOL(drm_mm_insert_node_in_range); 613 614static inline bool drm_mm_node_scanned_block(const struct drm_mm_node *node) 615{ 616 return test_bit(DRM_MM_NODE_SCANNED_BIT, &node->flags); 617} 618 619/** 620 * drm_mm_remove_node - Remove a memory node from the allocator. 621 * @node: drm_mm_node to remove 622 * 623 * This just removes a node from its drm_mm allocator. The node does not need to 624 * be cleared again before it can be re-inserted into this or any other drm_mm 625 * allocator. It is a bug to call this function on a unallocated node. 626 */ 627void drm_mm_remove_node(struct drm_mm_node *node) 628{ 629 struct drm_mm *mm = node->mm; 630 struct drm_mm_node *prev_node; 631 632 DRM_MM_BUG_ON(!drm_mm_node_allocated(node)); 633 DRM_MM_BUG_ON(drm_mm_node_scanned_block(node)); 634 635 prev_node = list_prev_entry(node, node_list); 636 637 if (drm_mm_hole_follows(node)) 638 rm_hole(node); 639 640 drm_mm_interval_tree_remove(node, &mm->interval_tree); 641 list_del(&node->node_list); 642 643 if (drm_mm_hole_follows(prev_node)) 644 rm_hole(prev_node); 645 add_hole(prev_node); 646 647 clear_bit_unlock(DRM_MM_NODE_ALLOCATED_BIT, &node->flags); 648} 649EXPORT_SYMBOL(drm_mm_remove_node); 650 651/** 652 * drm_mm_replace_node - move an allocation from @old to @new 653 * @old: drm_mm_node to remove from the allocator 654 * @new: drm_mm_node which should inherit @old's allocation 655 * 656 * This is useful for when drivers embed the drm_mm_node structure and hence 657 * can't move allocations by reassigning pointers. It's a combination of remove 658 * and insert with the guarantee that the allocation start will match. 659 */ 660void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new) 661{ 662 struct drm_mm *mm = old->mm; 663 664 DRM_MM_BUG_ON(!drm_mm_node_allocated(old)); 665 666 *new = *old; 667 668 __set_bit(DRM_MM_NODE_ALLOCATED_BIT, &new->flags); 669 list_replace(&old->node_list, &new->node_list); 670 rb_replace_node_cached(&old->rb, &new->rb, &mm->interval_tree); 671 672 if (drm_mm_hole_follows(old)) { 673 list_replace(&old->hole_stack, &new->hole_stack); 674 rb_replace_node_cached(&old->rb_hole_size, 675 &new->rb_hole_size, 676 &mm->holes_size); 677 rb_replace_node(&old->rb_hole_addr, 678 &new->rb_hole_addr, 679 &mm->holes_addr); 680 } 681 682 clear_bit_unlock(DRM_MM_NODE_ALLOCATED_BIT, &old->flags); 683} 684EXPORT_SYMBOL(drm_mm_replace_node); 685 686/** 687 * DOC: lru scan roster 688 * 689 * Very often GPUs need to have continuous allocations for a given object. When 690 * evicting objects to make space for a new one it is therefore not most 691 * efficient when we simply start to select all objects from the tail of an LRU 692 * until there's a suitable hole: Especially for big objects or nodes that 693 * otherwise have special allocation constraints there's a good chance we evict 694 * lots of (smaller) objects unnecessarily. 695 * 696 * The DRM range allocator supports this use-case through the scanning 697 * interfaces. First a scan operation needs to be initialized with 698 * drm_mm_scan_init() or drm_mm_scan_init_with_range(). The driver adds 699 * objects to the roster, probably by walking an LRU list, but this can be 700 * freely implemented. Eviction candidates are added using 701 * drm_mm_scan_add_block() until a suitable hole is found or there are no 702 * further evictable objects. Eviction roster metadata is tracked in &struct 703 * drm_mm_scan. 704 * 705 * The driver must walk through all objects again in exactly the reverse 706 * order to restore the allocator state. Note that while the allocator is used 707 * in the scan mode no other operation is allowed. 708 * 709 * Finally the driver evicts all objects selected (drm_mm_scan_remove_block() 710 * reported true) in the scan, and any overlapping nodes after color adjustment 711 * (drm_mm_scan_color_evict()). Adding and removing an object is O(1), and 712 * since freeing a node is also O(1) the overall complexity is 713 * O(scanned_objects). So like the free stack which needs to be walked before a 714 * scan operation even begins this is linear in the number of objects. It 715 * doesn't seem to hurt too badly. 716 */ 717 718/** 719 * drm_mm_scan_init_with_range - initialize range-restricted lru scanning 720 * @scan: scan state 721 * @mm: drm_mm to scan 722 * @size: size of the allocation 723 * @alignment: alignment of the allocation 724 * @color: opaque tag value to use for the allocation 725 * @start: start of the allowed range for the allocation 726 * @end: end of the allowed range for the allocation 727 * @mode: fine-tune the allocation search and placement 728 * 729 * This simply sets up the scanning routines with the parameters for the desired 730 * hole. 731 * 732 * Warning: 733 * As long as the scan list is non-empty, no other operations than 734 * adding/removing nodes to/from the scan list are allowed. 735 */ 736void drm_mm_scan_init_with_range(struct drm_mm_scan *scan, 737 struct drm_mm *mm, 738 u64 size, 739 u64 alignment, 740 unsigned long color, 741 u64 start, 742 u64 end, 743 enum drm_mm_insert_mode mode) 744{ 745 DRM_MM_BUG_ON(start >= end); 746 DRM_MM_BUG_ON(!size || size > end - start); 747 DRM_MM_BUG_ON(mm->scan_active); 748 749 scan->mm = mm; 750 751 if (alignment <= 1) 752 alignment = 0; 753 754 scan->color = color; 755 scan->alignment = alignment; 756 scan->remainder_mask = is_power_of_2(alignment) ? alignment - 1 : 0; 757 scan->size = size; 758 scan->mode = mode; 759 760 DRM_MM_BUG_ON(end <= start); 761 scan->range_start = start; 762 scan->range_end = end; 763 764 scan->hit_start = U64_MAX; 765 scan->hit_end = 0; 766} 767EXPORT_SYMBOL(drm_mm_scan_init_with_range); 768 769/** 770 * drm_mm_scan_add_block - add a node to the scan list 771 * @scan: the active drm_mm scanner 772 * @node: drm_mm_node to add 773 * 774 * Add a node to the scan list that might be freed to make space for the desired 775 * hole. 776 * 777 * Returns: 778 * True if a hole has been found, false otherwise. 779 */ 780bool drm_mm_scan_add_block(struct drm_mm_scan *scan, 781 struct drm_mm_node *node) 782{ 783 struct drm_mm *mm = scan->mm; 784 struct drm_mm_node *hole; 785 u64 hole_start, hole_end; 786 u64 col_start, col_end; 787 u64 adj_start, adj_end; 788 789 DRM_MM_BUG_ON(node->mm != mm); 790 DRM_MM_BUG_ON(!drm_mm_node_allocated(node)); 791 DRM_MM_BUG_ON(drm_mm_node_scanned_block(node)); 792 __set_bit(DRM_MM_NODE_SCANNED_BIT, &node->flags); 793 mm->scan_active++; 794 795 /* Remove this block from the node_list so that we enlarge the hole 796 * (distance between the end of our previous node and the start of 797 * or next), without poisoning the link so that we can restore it 798 * later in drm_mm_scan_remove_block(). 799 */ 800 hole = list_prev_entry(node, node_list); 801 DRM_MM_BUG_ON(list_next_entry(hole, node_list) != node); 802 __list_del_entry(&node->node_list); 803 804 hole_start = __drm_mm_hole_node_start(hole); 805 hole_end = __drm_mm_hole_node_end(hole); 806 807 col_start = hole_start; 808 col_end = hole_end; 809 if (mm->color_adjust) 810 mm->color_adjust(hole, scan->color, &col_start, &col_end); 811 812 adj_start = max(col_start, scan->range_start); 813 adj_end = min(col_end, scan->range_end); 814 if (adj_end <= adj_start || adj_end - adj_start < scan->size) 815 return false; 816 817 if (scan->mode == DRM_MM_INSERT_HIGH) 818 adj_start = adj_end - scan->size; 819 820 if (scan->alignment) { 821 u64 rem; 822 823 if (likely(scan->remainder_mask)) 824 rem = adj_start & scan->remainder_mask; 825 else 826 div64_u64_rem(adj_start, scan->alignment, &rem); 827 if (rem) { 828 adj_start -= rem; 829 if (scan->mode != DRM_MM_INSERT_HIGH) 830 adj_start += scan->alignment; 831 if (adj_start < max(col_start, scan->range_start) || 832 min(col_end, scan->range_end) - adj_start < scan->size) 833 return false; 834 835 if (adj_end <= adj_start || 836 adj_end - adj_start < scan->size) 837 return false; 838 } 839 } 840 841 scan->hit_start = adj_start; 842 scan->hit_end = adj_start + scan->size; 843 844 DRM_MM_BUG_ON(scan->hit_start >= scan->hit_end); 845 DRM_MM_BUG_ON(scan->hit_start < hole_start); 846 DRM_MM_BUG_ON(scan->hit_end > hole_end); 847 848 return true; 849} 850EXPORT_SYMBOL(drm_mm_scan_add_block); 851 852/** 853 * drm_mm_scan_remove_block - remove a node from the scan list 854 * @scan: the active drm_mm scanner 855 * @node: drm_mm_node to remove 856 * 857 * Nodes **must** be removed in exactly the reverse order from the scan list as 858 * they have been added (e.g. using list_add() as they are added and then 859 * list_for_each() over that eviction list to remove), otherwise the internal 860 * state of the memory manager will be corrupted. 861 * 862 * When the scan list is empty, the selected memory nodes can be freed. An 863 * immediately following drm_mm_insert_node_in_range_generic() or one of the 864 * simpler versions of that function with !DRM_MM_SEARCH_BEST will then return 865 * the just freed block (because it's at the top of the free_stack list). 866 * 867 * Returns: 868 * True if this block should be evicted, false otherwise. Will always 869 * return false when no hole has been found. 870 */ 871bool drm_mm_scan_remove_block(struct drm_mm_scan *scan, 872 struct drm_mm_node *node) 873{ 874 struct drm_mm_node *prev_node; 875 876 DRM_MM_BUG_ON(node->mm != scan->mm); 877 DRM_MM_BUG_ON(!drm_mm_node_scanned_block(node)); 878 __clear_bit(DRM_MM_NODE_SCANNED_BIT, &node->flags); 879 880 DRM_MM_BUG_ON(!node->mm->scan_active); 881 node->mm->scan_active--; 882 883 /* During drm_mm_scan_add_block() we decoupled this node leaving 884 * its pointers intact. Now that the caller is walking back along 885 * the eviction list we can restore this block into its rightful 886 * place on the full node_list. To confirm that the caller is walking 887 * backwards correctly we check that prev_node->next == node->next, 888 * i.e. both believe the same node should be on the other side of the 889 * hole. 890 */ 891 prev_node = list_prev_entry(node, node_list); 892 DRM_MM_BUG_ON(list_next_entry(prev_node, node_list) != 893 list_next_entry(node, node_list)); 894 list_add(&node->node_list, &prev_node->node_list); 895 896 return (node->start + node->size > scan->hit_start && 897 node->start < scan->hit_end); 898} 899EXPORT_SYMBOL(drm_mm_scan_remove_block); 900 901/** 902 * drm_mm_scan_color_evict - evict overlapping nodes on either side of hole 903 * @scan: drm_mm scan with target hole 904 * 905 * After completing an eviction scan and removing the selected nodes, we may 906 * need to remove a few more nodes from either side of the target hole if 907 * mm.color_adjust is being used. 908 * 909 * Returns: 910 * A node to evict, or NULL if there are no overlapping nodes. 911 */ 912struct drm_mm_node *drm_mm_scan_color_evict(struct drm_mm_scan *scan) 913{ 914 struct drm_mm *mm = scan->mm; 915 struct drm_mm_node *hole; 916 u64 hole_start, hole_end; 917 918 DRM_MM_BUG_ON(list_empty(&mm->hole_stack)); 919 920 if (!mm->color_adjust) 921 return NULL; 922 923 /* 924 * The hole found during scanning should ideally be the first element 925 * in the hole_stack list, but due to side-effects in the driver it 926 * may not be. 927 */ 928 list_for_each_entry(hole, &mm->hole_stack, hole_stack) { 929 hole_start = __drm_mm_hole_node_start(hole); 930 hole_end = hole_start + hole->hole_size; 931 932 if (hole_start <= scan->hit_start && 933 hole_end >= scan->hit_end) 934 break; 935 } 936 937 /* We should only be called after we found the hole previously */ 938 DRM_MM_BUG_ON(&hole->hole_stack == &mm->hole_stack); 939 if (unlikely(&hole->hole_stack == &mm->hole_stack)) 940 return NULL; 941 942 DRM_MM_BUG_ON(hole_start > scan->hit_start); 943 DRM_MM_BUG_ON(hole_end < scan->hit_end); 944 945 mm->color_adjust(hole, scan->color, &hole_start, &hole_end); 946 if (hole_start > scan->hit_start) 947 return hole; 948 if (hole_end < scan->hit_end) 949 return list_next_entry(hole, node_list); 950 951 return NULL; 952} 953EXPORT_SYMBOL(drm_mm_scan_color_evict); 954 955/** 956 * drm_mm_init - initialize a drm-mm allocator 957 * @mm: the drm_mm structure to initialize 958 * @start: start of the range managed by @mm 959 * @size: end of the range managed by @mm 960 * 961 * Note that @mm must be cleared to 0 before calling this function. 962 */ 963void drm_mm_init(struct drm_mm *mm, u64 start, u64 size) 964{ 965 DRM_MM_BUG_ON(start + size <= start); 966 967 mm->color_adjust = NULL; 968 969 INIT_LIST_HEAD(&mm->hole_stack); 970 mm->interval_tree = RB_ROOT_CACHED; 971 mm->holes_size = RB_ROOT_CACHED; 972 mm->holes_addr = RB_ROOT; 973 974 /* Clever trick to avoid a special case in the free hole tracking. */ 975 INIT_LIST_HEAD(&mm->head_node.node_list); 976 mm->head_node.flags = 0; 977 mm->head_node.mm = mm; 978 mm->head_node.start = start + size; 979 mm->head_node.size = -size; 980 add_hole(&mm->head_node); 981 982 mm->scan_active = 0; 983 984#ifdef CONFIG_DRM_DEBUG_MM 985 stack_depot_init(); 986#endif 987} 988EXPORT_SYMBOL(drm_mm_init); 989 990/** 991 * drm_mm_takedown - clean up a drm_mm allocator 992 * @mm: drm_mm allocator to clean up 993 * 994 * Note that it is a bug to call this function on an allocator which is not 995 * clean. 996 */ 997void drm_mm_takedown(struct drm_mm *mm) 998{ 999 if (WARN(!drm_mm_clean(mm), 1000 "Memory manager not clean during takedown.\n")) 1001 show_leaks(mm); 1002} 1003EXPORT_SYMBOL(drm_mm_takedown); 1004 1005static u64 drm_mm_dump_hole(struct drm_printer *p, const struct drm_mm_node *entry) 1006{ 1007 u64 start, size; 1008 1009 size = entry->hole_size; 1010 if (size) { 1011 start = drm_mm_hole_node_start(entry); 1012 drm_printf(p, "%#018llx-%#018llx: %llu: free\n", 1013 start, start + size, size); 1014 } 1015 1016 return size; 1017} 1018/** 1019 * drm_mm_print - print allocator state 1020 * @mm: drm_mm allocator to print 1021 * @p: DRM printer to use 1022 */ 1023void drm_mm_print(const struct drm_mm *mm, struct drm_printer *p) 1024{ 1025 const struct drm_mm_node *entry; 1026 u64 total_used = 0, total_free = 0, total = 0; 1027 1028 total_free += drm_mm_dump_hole(p, &mm->head_node); 1029 1030 drm_mm_for_each_node(entry, mm) { 1031 drm_printf(p, "%#018llx-%#018llx: %llu: used\n", entry->start, 1032 entry->start + entry->size, entry->size); 1033 total_used += entry->size; 1034 total_free += drm_mm_dump_hole(p, entry); 1035 } 1036 total = total_free + total_used; 1037 1038 drm_printf(p, "total: %llu, used %llu free %llu\n", total, 1039 total_used, total_free); 1040} 1041EXPORT_SYMBOL(drm_mm_print); 1042