| 1 | /************************************************************************** |
| 2 | * |
| 3 | * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., USA. |
| 4 | * All Rights Reserved. |
| 5 | * |
| 6 | * Permission is hereby granted, free of charge, to any person obtaining a |
| 7 | * copy of this software and associated documentation files (the |
| 8 | * "Software"), to deal in the Software without restriction, including |
| 9 | * without limitation the rights to use, copy, modify, merge, publish, |
| 10 | * distribute, sub license, and/or sell copies of the Software, and to |
| 11 | * permit persons to whom the Software is furnished to do so, subject to |
| 12 | * the following conditions: |
| 13 | * |
| 14 | * The above copyright notice and this permission notice (including the |
| 15 | * next paragraph) shall be included in all copies or substantial portions |
| 16 | * of the Software. |
| 17 | * |
| 18 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 19 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 20 | * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL |
| 21 | * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, |
| 22 | * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR |
| 23 | * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE |
| 24 | * USE OR OTHER DEALINGS IN THE SOFTWARE. |
| 25 | * |
| 26 | * |
| 27 | **************************************************************************/ |
| 28 | |
| 29 | /* |
| 30 | * Generic simple memory manager implementation. Intended to be used as a base |
| 31 | * class implementation for more advanced memory managers. |
| 32 | * |
| 33 | * Note that the algorithm used is quite simple and there might be substantial |
| 34 | * performance gains if a smarter free list is implemented. Currently it is just an |
| 35 | * unordered stack of free regions. This could easily be improved if an RB-tree |
| 36 | * is used instead. At least if we expect heavy fragmentation. |
| 37 | * |
| 38 | * Aligned allocations can also see improvement. |
| 39 | * |
| 40 | * Authors: |
| 41 | * Thomas Hellström <thomas-at-tungstengraphics-dot-com> |
| 42 | */ |
| 43 | |
| 44 | #include <drm/drmP.h> |
| 45 | #include <drm/drm_mm.h> |
| 46 | #include <linux/slab.h> |
| 47 | #include <linux/seq_file.h> |
| 48 | #include <linux/export.h> |
| 49 | #include <linux/printk.h> |
| 50 | #include <asm/bug.h> |
| 51 | |
| 52 | /** |
| 53 | * DOC: Overview |
| 54 | * |
| 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. |
| 59 | * |
| 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 allocations of its own, so if |
| 63 | * drivers choose not to embed nodes they need to still allocate them |
| 64 | * themselves. |
| 65 | * |
| 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 | * depencies in the driver load sequence. |
| 72 | * |
| 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). |
| 79 | * |
| 80 | * drm_mm supports a few features: Alignment and range restrictions can be |
| 81 | * supplied. Further more every &drm_mm_node has a color value (which is just an |
| 82 | * opaqua 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 |
| 85 | * graphics TT. |
| 86 | * |
| 87 | * Two behaviors are supported for searching and allocating: bottom-up and top-down. |
| 88 | * The default is bottom-up. Top-down allocation can be used if the memory area |
| 89 | * has different restrictions, or just to reduce fragmentation. |
| 90 | * |
| 91 | * Finally iteration helpers to walk all nodes and all holes are provided as are |
| 92 | * some basic allocator dumpers for debugging. |
| 93 | */ |
| 94 | |
| 95 | static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm, |
| 96 | unsigned long size, |
| 97 | unsigned alignment, |
| 98 | unsigned long color, |
| 99 | enum drm_mm_search_flags flags); |
| 100 | static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm, |
| 101 | unsigned long size, |
| 102 | unsigned alignment, |
| 103 | unsigned long color, |
| 104 | unsigned long start, |
| 105 | unsigned long end, |
| 106 | enum drm_mm_search_flags flags); |
| 107 | |
| 108 | static void drm_mm_insert_helper(struct drm_mm_node *hole_node, |
| 109 | struct drm_mm_node *node, |
| 110 | unsigned long size, unsigned alignment, |
| 111 | unsigned long color, |
| 112 | enum drm_mm_allocator_flags flags) |
| 113 | { |
| 114 | struct drm_mm *mm = hole_node->mm; |
| 115 | unsigned long hole_start = drm_mm_hole_node_start(hole_node); |
| 116 | unsigned long hole_end = drm_mm_hole_node_end(hole_node); |
| 117 | unsigned long adj_start = hole_start; |
| 118 | unsigned long adj_end = hole_end; |
| 119 | |
| 120 | BUG_ON(node->allocated); |
| 121 | |
| 122 | if (mm->color_adjust) |
| 123 | mm->color_adjust(hole_node, color, &adj_start, &adj_end); |
| 124 | |
| 125 | if (flags & DRM_MM_CREATE_TOP) |
| 126 | adj_start = adj_end - size; |
| 127 | |
| 128 | if (alignment) { |
| 129 | unsigned tmp = adj_start % alignment; |
| 130 | if (tmp) { |
| 131 | if (flags & DRM_MM_CREATE_TOP) |
| 132 | adj_start -= tmp; |
| 133 | else |
| 134 | adj_start += alignment - tmp; |
| 135 | } |
| 136 | } |
| 137 | |
| 138 | BUG_ON(adj_start < hole_start); |
| 139 | BUG_ON(adj_end > hole_end); |
| 140 | |
| 141 | if (adj_start == hole_start) { |
| 142 | hole_node->hole_follows = 0; |
| 143 | list_del(&hole_node->hole_stack); |
| 144 | } |
| 145 | |
| 146 | node->start = adj_start; |
| 147 | node->size = size; |
| 148 | node->mm = mm; |
| 149 | node->color = color; |
| 150 | node->allocated = 1; |
| 151 | |
| 152 | INIT_LIST_HEAD(&node->hole_stack); |
| 153 | list_add(&node->node_list, &hole_node->node_list); |
| 154 | |
| 155 | BUG_ON(node->start + node->size > adj_end); |
| 156 | |
| 157 | node->hole_follows = 0; |
| 158 | if (__drm_mm_hole_node_start(node) < hole_end) { |
| 159 | list_add(&node->hole_stack, &mm->hole_stack); |
| 160 | node->hole_follows = 1; |
| 161 | } |
| 162 | } |
| 163 | |
| 164 | /** |
| 165 | * drm_mm_reserve_node - insert an pre-initialized node |
| 166 | * @mm: drm_mm allocator to insert @node into |
| 167 | * @node: drm_mm_node to insert |
| 168 | * |
| 169 | * This functions inserts an already set-up drm_mm_node into the allocator, |
| 170 | * meaning that start, size and color must be set by the caller. This is useful |
| 171 | * to initialize the allocator with preallocated objects which must be set-up |
| 172 | * before the range allocator can be set-up, e.g. when taking over a firmware |
| 173 | * framebuffer. |
| 174 | * |
| 175 | * Returns: |
| 176 | * 0 on success, -ENOSPC if there's no hole where @node is. |
| 177 | */ |
| 178 | int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node) |
| 179 | { |
| 180 | struct drm_mm_node *hole; |
| 181 | unsigned long end = node->start + node->size; |
| 182 | unsigned long hole_start; |
| 183 | unsigned long hole_end; |
| 184 | |
| 185 | BUG_ON(node == NULL); |
| 186 | |
| 187 | /* Find the relevant hole to add our node to */ |
| 188 | drm_mm_for_each_hole(hole, mm, hole_start, hole_end) { |
| 189 | if (hole_start > node->start || hole_end < end) |
| 190 | continue; |
| 191 | |
| 192 | node->mm = mm; |
| 193 | node->allocated = 1; |
| 194 | |
| 195 | INIT_LIST_HEAD(&node->hole_stack); |
| 196 | list_add(&node->node_list, &hole->node_list); |
| 197 | |
| 198 | if (node->start == hole_start) { |
| 199 | hole->hole_follows = 0; |
| 200 | list_del_init(&hole->hole_stack); |
| 201 | } |
| 202 | |
| 203 | node->hole_follows = 0; |
| 204 | if (end != hole_end) { |
| 205 | list_add(&node->hole_stack, &mm->hole_stack); |
| 206 | node->hole_follows = 1; |
| 207 | } |
| 208 | |
| 209 | return 0; |
| 210 | } |
| 211 | |
| 212 | return -ENOSPC; |
| 213 | } |
| 214 | EXPORT_SYMBOL(drm_mm_reserve_node); |
| 215 | |
| 216 | /** |
| 217 | * drm_mm_insert_node_generic - search for space and insert @node |
| 218 | * @mm: drm_mm to allocate from |
| 219 | * @node: preallocate node to insert |
| 220 | * @size: size of the allocation |
| 221 | * @alignment: alignment of the allocation |
| 222 | * @color: opaque tag value to use for this node |
| 223 | * @sflags: flags to fine-tune the allocation search |
| 224 | * @aflags: flags to fine-tune the allocation behavior |
| 225 | * |
| 226 | * The preallocated node must be cleared to 0. |
| 227 | * |
| 228 | * Returns: |
| 229 | * 0 on success, -ENOSPC if there's no suitable hole. |
| 230 | */ |
| 231 | int drm_mm_insert_node_generic(struct drm_mm *mm, struct drm_mm_node *node, |
| 232 | unsigned long size, unsigned alignment, |
| 233 | unsigned long color, |
| 234 | enum drm_mm_search_flags sflags, |
| 235 | enum drm_mm_allocator_flags aflags) |
| 236 | { |
| 237 | struct drm_mm_node *hole_node; |
| 238 | |
| 239 | hole_node = drm_mm_search_free_generic(mm, size, alignment, |
| 240 | color, sflags); |
| 241 | if (!hole_node) |
| 242 | return -ENOSPC; |
| 243 | |
| 244 | drm_mm_insert_helper(hole_node, node, size, alignment, color, aflags); |
| 245 | return 0; |
| 246 | } |
| 247 | EXPORT_SYMBOL(drm_mm_insert_node_generic); |
| 248 | |
| 249 | static void drm_mm_insert_helper_range(struct drm_mm_node *hole_node, |
| 250 | struct drm_mm_node *node, |
| 251 | unsigned long size, unsigned alignment, |
| 252 | unsigned long color, |
| 253 | unsigned long start, unsigned long end, |
| 254 | enum drm_mm_allocator_flags flags) |
| 255 | { |
| 256 | struct drm_mm *mm = hole_node->mm; |
| 257 | unsigned long hole_start = drm_mm_hole_node_start(hole_node); |
| 258 | unsigned long hole_end = drm_mm_hole_node_end(hole_node); |
| 259 | unsigned long adj_start = hole_start; |
| 260 | unsigned long adj_end = hole_end; |
| 261 | |
| 262 | BUG_ON(!hole_node->hole_follows || node->allocated); |
| 263 | |
| 264 | if (adj_start < start) |
| 265 | adj_start = start; |
| 266 | if (adj_end > end) |
| 267 | adj_end = end; |
| 268 | |
| 269 | if (flags & DRM_MM_CREATE_TOP) |
| 270 | adj_start = adj_end - size; |
| 271 | |
| 272 | if (mm->color_adjust) |
| 273 | mm->color_adjust(hole_node, color, &adj_start, &adj_end); |
| 274 | |
| 275 | if (alignment) { |
| 276 | unsigned tmp = adj_start % alignment; |
| 277 | if (tmp) { |
| 278 | if (flags & DRM_MM_CREATE_TOP) |
| 279 | adj_start -= tmp; |
| 280 | else |
| 281 | adj_start += alignment - tmp; |
| 282 | } |
| 283 | } |
| 284 | |
| 285 | if (adj_start == hole_start) { |
| 286 | hole_node->hole_follows = 0; |
| 287 | list_del(&hole_node->hole_stack); |
| 288 | } |
| 289 | |
| 290 | node->start = adj_start; |
| 291 | node->size = size; |
| 292 | node->mm = mm; |
| 293 | node->color = color; |
| 294 | node->allocated = 1; |
| 295 | |
| 296 | INIT_LIST_HEAD(&node->hole_stack); |
| 297 | list_add(&node->node_list, &hole_node->node_list); |
| 298 | |
| 299 | BUG_ON(node->start < start); |
| 300 | BUG_ON(node->start < adj_start); |
| 301 | BUG_ON(node->start + node->size > adj_end); |
| 302 | BUG_ON(node->start + node->size > end); |
| 303 | |
| 304 | node->hole_follows = 0; |
| 305 | if (__drm_mm_hole_node_start(node) < hole_end) { |
| 306 | list_add(&node->hole_stack, &mm->hole_stack); |
| 307 | node->hole_follows = 1; |
| 308 | } |
| 309 | } |
| 310 | |
| 311 | /** |
| 312 | * drm_mm_insert_node_in_range_generic - ranged search for space and insert @node |
| 313 | * @mm: drm_mm to allocate from |
| 314 | * @node: preallocate node to insert |
| 315 | * @size: size of the allocation |
| 316 | * @alignment: alignment of the allocation |
| 317 | * @color: opaque tag value to use for this node |
| 318 | * @start: start of the allowed range for this node |
| 319 | * @end: end of the allowed range for this node |
| 320 | * @sflags: flags to fine-tune the allocation search |
| 321 | * @aflags: flags to fine-tune the allocation behavior |
| 322 | * |
| 323 | * The preallocated node must be cleared to 0. |
| 324 | * |
| 325 | * Returns: |
| 326 | * 0 on success, -ENOSPC if there's no suitable hole. |
| 327 | */ |
| 328 | int drm_mm_insert_node_in_range_generic(struct drm_mm *mm, struct drm_mm_node *node, |
| 329 | unsigned long size, unsigned alignment, |
| 330 | unsigned long color, |
| 331 | unsigned long start, unsigned long end, |
| 332 | enum drm_mm_search_flags sflags, |
| 333 | enum drm_mm_allocator_flags aflags) |
| 334 | { |
| 335 | struct drm_mm_node *hole_node; |
| 336 | |
| 337 | hole_node = drm_mm_search_free_in_range_generic(mm, |
| 338 | size, alignment, color, |
| 339 | start, end, sflags); |
| 340 | if (!hole_node) |
| 341 | return -ENOSPC; |
| 342 | |
| 343 | drm_mm_insert_helper_range(hole_node, node, |
| 344 | size, alignment, color, |
| 345 | start, end, aflags); |
| 346 | return 0; |
| 347 | } |
| 348 | EXPORT_SYMBOL(drm_mm_insert_node_in_range_generic); |
| 349 | |
| 350 | /** |
| 351 | * drm_mm_remove_node - Remove a memory node from the allocator. |
| 352 | * @node: drm_mm_node to remove |
| 353 | * |
| 354 | * This just removes a node from its drm_mm allocator. The node does not need to |
| 355 | * be cleared again before it can be re-inserted into this or any other drm_mm |
| 356 | * allocator. It is a bug to call this function on a un-allocated node. |
| 357 | */ |
| 358 | void drm_mm_remove_node(struct drm_mm_node *node) |
| 359 | { |
| 360 | struct drm_mm *mm = node->mm; |
| 361 | struct drm_mm_node *prev_node; |
| 362 | |
| 363 | if (WARN_ON(!node->allocated)) |
| 364 | return; |
| 365 | |
| 366 | BUG_ON(node->scanned_block || node->scanned_prev_free |
| 367 | || node->scanned_next_free); |
| 368 | |
| 369 | prev_node = |
| 370 | list_entry(node->node_list.prev, struct drm_mm_node, node_list); |
| 371 | |
| 372 | if (node->hole_follows) { |
| 373 | BUG_ON(__drm_mm_hole_node_start(node) == |
| 374 | __drm_mm_hole_node_end(node)); |
| 375 | list_del(&node->hole_stack); |
| 376 | } else |
| 377 | BUG_ON(__drm_mm_hole_node_start(node) != |
| 378 | __drm_mm_hole_node_end(node)); |
| 379 | |
| 380 | |
| 381 | if (!prev_node->hole_follows) { |
| 382 | prev_node->hole_follows = 1; |
| 383 | list_add(&prev_node->hole_stack, &mm->hole_stack); |
| 384 | } else |
| 385 | list_move(&prev_node->hole_stack, &mm->hole_stack); |
| 386 | |
| 387 | list_del(&node->node_list); |
| 388 | node->allocated = 0; |
| 389 | } |
| 390 | EXPORT_SYMBOL(drm_mm_remove_node); |
| 391 | |
| 392 | static int check_free_hole(unsigned long start, unsigned long end, |
| 393 | unsigned long size, unsigned alignment) |
| 394 | { |
| 395 | if (end - start < size) |
| 396 | return 0; |
| 397 | |
| 398 | if (alignment) { |
| 399 | unsigned tmp = start % alignment; |
| 400 | if (tmp) |
| 401 | start += alignment - tmp; |
| 402 | } |
| 403 | |
| 404 | return end >= start + size; |
| 405 | } |
| 406 | |
| 407 | static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm, |
| 408 | unsigned long size, |
| 409 | unsigned alignment, |
| 410 | unsigned long color, |
| 411 | enum drm_mm_search_flags flags) |
| 412 | { |
| 413 | struct drm_mm_node *entry; |
| 414 | struct drm_mm_node *best; |
| 415 | unsigned long adj_start; |
| 416 | unsigned long adj_end; |
| 417 | unsigned long best_size; |
| 418 | |
| 419 | BUG_ON(mm->scanned_blocks); |
| 420 | |
| 421 | best = NULL; |
| 422 | best_size = ~0UL; |
| 423 | |
| 424 | __drm_mm_for_each_hole(entry, mm, adj_start, adj_end, |
| 425 | flags & DRM_MM_SEARCH_BELOW) { |
| 426 | unsigned long hole_size = adj_end - adj_start; |
| 427 | |
| 428 | if (mm->color_adjust) { |
| 429 | mm->color_adjust(entry, color, &adj_start, &adj_end); |
| 430 | if (adj_end <= adj_start) |
| 431 | continue; |
| 432 | } |
| 433 | |
| 434 | if (!check_free_hole(adj_start, adj_end, size, alignment)) |
| 435 | continue; |
| 436 | |
| 437 | if (!(flags & DRM_MM_SEARCH_BEST)) |
| 438 | return entry; |
| 439 | |
| 440 | if (hole_size < best_size) { |
| 441 | best = entry; |
| 442 | best_size = hole_size; |
| 443 | } |
| 444 | } |
| 445 | |
| 446 | return best; |
| 447 | } |
| 448 | |
| 449 | static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm, |
| 450 | unsigned long size, |
| 451 | unsigned alignment, |
| 452 | unsigned long color, |
| 453 | unsigned long start, |
| 454 | unsigned long end, |
| 455 | enum drm_mm_search_flags flags) |
| 456 | { |
| 457 | struct drm_mm_node *entry; |
| 458 | struct drm_mm_node *best; |
| 459 | unsigned long adj_start; |
| 460 | unsigned long adj_end; |
| 461 | unsigned long best_size; |
| 462 | |
| 463 | BUG_ON(mm->scanned_blocks); |
| 464 | |
| 465 | best = NULL; |
| 466 | best_size = ~0UL; |
| 467 | |
| 468 | __drm_mm_for_each_hole(entry, mm, adj_start, adj_end, |
| 469 | flags & DRM_MM_SEARCH_BELOW) { |
| 470 | unsigned long hole_size = adj_end - adj_start; |
| 471 | |
| 472 | if (adj_start < start) |
| 473 | adj_start = start; |
| 474 | if (adj_end > end) |
| 475 | adj_end = end; |
| 476 | |
| 477 | if (mm->color_adjust) { |
| 478 | mm->color_adjust(entry, color, &adj_start, &adj_end); |
| 479 | if (adj_end <= adj_start) |
| 480 | continue; |
| 481 | } |
| 482 | |
| 483 | if (!check_free_hole(adj_start, adj_end, size, alignment)) |
| 484 | continue; |
| 485 | |
| 486 | if (!(flags & DRM_MM_SEARCH_BEST)) |
| 487 | return entry; |
| 488 | |
| 489 | if (hole_size < best_size) { |
| 490 | best = entry; |
| 491 | best_size = hole_size; |
| 492 | } |
| 493 | } |
| 494 | |
| 495 | return best; |
| 496 | } |
| 497 | |
| 498 | /** |
| 499 | * drm_mm_replace_node - move an allocation from @old to @new |
| 500 | * @old: drm_mm_node to remove from the allocator |
| 501 | * @new: drm_mm_node which should inherit @old's allocation |
| 502 | * |
| 503 | * This is useful for when drivers embed the drm_mm_node structure and hence |
| 504 | * can't move allocations by reassigning pointers. It's a combination of remove |
| 505 | * and insert with the guarantee that the allocation start will match. |
| 506 | */ |
| 507 | void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new) |
| 508 | { |
| 509 | list_replace(&old->node_list, &new->node_list); |
| 510 | list_replace(&old->hole_stack, &new->hole_stack); |
| 511 | new->hole_follows = old->hole_follows; |
| 512 | new->mm = old->mm; |
| 513 | new->start = old->start; |
| 514 | new->size = old->size; |
| 515 | new->color = old->color; |
| 516 | |
| 517 | old->allocated = 0; |
| 518 | new->allocated = 1; |
| 519 | } |
| 520 | EXPORT_SYMBOL(drm_mm_replace_node); |
| 521 | |
| 522 | /** |
| 523 | * DOC: lru scan roaster |
| 524 | * |
| 525 | * Very often GPUs need to have continuous allocations for a given object. When |
| 526 | * evicting objects to make space for a new one it is therefore not most |
| 527 | * efficient when we simply start to select all objects from the tail of an LRU |
| 528 | * until there's a suitable hole: Especially for big objects or nodes that |
| 529 | * otherwise have special allocation constraints there's a good chance we evict |
| 530 | * lots of (smaller) objects unecessarily. |
| 531 | * |
| 532 | * The DRM range allocator supports this use-case through the scanning |
| 533 | * interfaces. First a scan operation needs to be initialized with |
| 534 | * drm_mm_init_scan() or drm_mm_init_scan_with_range(). The the driver adds |
| 535 | * objects to the roaster (probably by walking an LRU list, but this can be |
| 536 | * freely implemented) until a suitable hole is found or there's no further |
| 537 | * evitable object. |
| 538 | * |
| 539 | * The the driver must walk through all objects again in exactly the reverse |
| 540 | * order to restore the allocator state. Note that while the allocator is used |
| 541 | * in the scan mode no other operation is allowed. |
| 542 | * |
| 543 | * Finally the driver evicts all objects selected in the scan. Adding and |
| 544 | * removing an object is O(1), and since freeing a node is also O(1) the overall |
| 545 | * complexity is O(scanned_objects). So like the free stack which needs to be |
| 546 | * walked before a scan operation even begins this is linear in the number of |
| 547 | * objects. It doesn't seem to hurt badly. |
| 548 | */ |
| 549 | |
| 550 | /** |
| 551 | * drm_mm_init_scan - initialize lru scanning |
| 552 | * @mm: drm_mm to scan |
| 553 | * @size: size of the allocation |
| 554 | * @alignment: alignment of the allocation |
| 555 | * @color: opaque tag value to use for the allocation |
| 556 | * |
| 557 | * This simply sets up the scanning routines with the parameters for the desired |
| 558 | * hole. Note that there's no need to specify allocation flags, since they only |
| 559 | * change the place a node is allocated from within a suitable hole. |
| 560 | * |
| 561 | * Warning: |
| 562 | * As long as the scan list is non-empty, no other operations than |
| 563 | * adding/removing nodes to/from the scan list are allowed. |
| 564 | */ |
| 565 | void drm_mm_init_scan(struct drm_mm *mm, |
| 566 | unsigned long size, |
| 567 | unsigned alignment, |
| 568 | unsigned long color) |
| 569 | { |
| 570 | mm->scan_color = color; |
| 571 | mm->scan_alignment = alignment; |
| 572 | mm->scan_size = size; |
| 573 | mm->scanned_blocks = 0; |
| 574 | mm->scan_hit_start = 0; |
| 575 | mm->scan_hit_end = 0; |
| 576 | mm->scan_check_range = 0; |
| 577 | mm->prev_scanned_node = NULL; |
| 578 | } |
| 579 | EXPORT_SYMBOL(drm_mm_init_scan); |
| 580 | |
| 581 | /** |
| 582 | * drm_mm_init_scan - initialize range-restricted lru scanning |
| 583 | * @mm: drm_mm to scan |
| 584 | * @size: size of the allocation |
| 585 | * @alignment: alignment of the allocation |
| 586 | * @color: opaque tag value to use for the allocation |
| 587 | * @start: start of the allowed range for the allocation |
| 588 | * @end: end of the allowed range for the allocation |
| 589 | * |
| 590 | * This simply sets up the scanning routines with the parameters for the desired |
| 591 | * hole. Note that there's no need to specify allocation flags, since they only |
| 592 | * change the place a node is allocated from within a suitable hole. |
| 593 | * |
| 594 | * Warning: |
| 595 | * As long as the scan list is non-empty, no other operations than |
| 596 | * adding/removing nodes to/from the scan list are allowed. |
| 597 | */ |
| 598 | void drm_mm_init_scan_with_range(struct drm_mm *mm, |
| 599 | unsigned long size, |
| 600 | unsigned alignment, |
| 601 | unsigned long color, |
| 602 | unsigned long start, |
| 603 | unsigned long end) |
| 604 | { |
| 605 | mm->scan_color = color; |
| 606 | mm->scan_alignment = alignment; |
| 607 | mm->scan_size = size; |
| 608 | mm->scanned_blocks = 0; |
| 609 | mm->scan_hit_start = 0; |
| 610 | mm->scan_hit_end = 0; |
| 611 | mm->scan_start = start; |
| 612 | mm->scan_end = end; |
| 613 | mm->scan_check_range = 1; |
| 614 | mm->prev_scanned_node = NULL; |
| 615 | } |
| 616 | EXPORT_SYMBOL(drm_mm_init_scan_with_range); |
| 617 | |
| 618 | /** |
| 619 | * drm_mm_scan_add_block - add a node to the scan list |
| 620 | * @node: drm_mm_node to add |
| 621 | * |
| 622 | * Add a node to the scan list that might be freed to make space for the desired |
| 623 | * hole. |
| 624 | * |
| 625 | * Returns: |
| 626 | * True if a hole has been found, false otherwise. |
| 627 | */ |
| 628 | bool drm_mm_scan_add_block(struct drm_mm_node *node) |
| 629 | { |
| 630 | struct drm_mm *mm = node->mm; |
| 631 | struct drm_mm_node *prev_node; |
| 632 | unsigned long hole_start, hole_end; |
| 633 | unsigned long adj_start, adj_end; |
| 634 | |
| 635 | mm->scanned_blocks++; |
| 636 | |
| 637 | BUG_ON(node->scanned_block); |
| 638 | node->scanned_block = 1; |
| 639 | |
| 640 | prev_node = list_entry(node->node_list.prev, struct drm_mm_node, |
| 641 | node_list); |
| 642 | |
| 643 | node->scanned_preceeds_hole = prev_node->hole_follows; |
| 644 | prev_node->hole_follows = 1; |
| 645 | list_del(&node->node_list); |
| 646 | node->node_list.prev = &prev_node->node_list; |
| 647 | node->node_list.next = &mm->prev_scanned_node->node_list; |
| 648 | mm->prev_scanned_node = node; |
| 649 | |
| 650 | adj_start = hole_start = drm_mm_hole_node_start(prev_node); |
| 651 | adj_end = hole_end = drm_mm_hole_node_end(prev_node); |
| 652 | |
| 653 | if (mm->scan_check_range) { |
| 654 | if (adj_start < mm->scan_start) |
| 655 | adj_start = mm->scan_start; |
| 656 | if (adj_end > mm->scan_end) |
| 657 | adj_end = mm->scan_end; |
| 658 | } |
| 659 | |
| 660 | if (mm->color_adjust) |
| 661 | mm->color_adjust(prev_node, mm->scan_color, |
| 662 | &adj_start, &adj_end); |
| 663 | |
| 664 | if (check_free_hole(adj_start, adj_end, |
| 665 | mm->scan_size, mm->scan_alignment)) { |
| 666 | mm->scan_hit_start = hole_start; |
| 667 | mm->scan_hit_end = hole_end; |
| 668 | return true; |
| 669 | } |
| 670 | |
| 671 | return false; |
| 672 | } |
| 673 | EXPORT_SYMBOL(drm_mm_scan_add_block); |
| 674 | |
| 675 | /** |
| 676 | * drm_mm_scan_remove_block - remove a node from the scan list |
| 677 | * @node: drm_mm_node to remove |
| 678 | * |
| 679 | * Nodes _must_ be removed in the exact same order from the scan list as they |
| 680 | * have been added, otherwise the internal state of the memory manager will be |
| 681 | * corrupted. |
| 682 | * |
| 683 | * When the scan list is empty, the selected memory nodes can be freed. An |
| 684 | * immediately following drm_mm_search_free with !DRM_MM_SEARCH_BEST will then |
| 685 | * return the just freed block (because its at the top of the free_stack list). |
| 686 | * |
| 687 | * Returns: |
| 688 | * True if this block should be evicted, false otherwise. Will always |
| 689 | * return false when no hole has been found. |
| 690 | */ |
| 691 | bool drm_mm_scan_remove_block(struct drm_mm_node *node) |
| 692 | { |
| 693 | struct drm_mm *mm = node->mm; |
| 694 | struct drm_mm_node *prev_node; |
| 695 | |
| 696 | mm->scanned_blocks--; |
| 697 | |
| 698 | BUG_ON(!node->scanned_block); |
| 699 | node->scanned_block = 0; |
| 700 | |
| 701 | prev_node = list_entry(node->node_list.prev, struct drm_mm_node, |
| 702 | node_list); |
| 703 | |
| 704 | prev_node->hole_follows = node->scanned_preceeds_hole; |
| 705 | list_add(&node->node_list, &prev_node->node_list); |
| 706 | |
| 707 | return (drm_mm_hole_node_end(node) > mm->scan_hit_start && |
| 708 | node->start < mm->scan_hit_end); |
| 709 | } |
| 710 | EXPORT_SYMBOL(drm_mm_scan_remove_block); |
| 711 | |
| 712 | /** |
| 713 | * drm_mm_clean - checks whether an allocator is clean |
| 714 | * @mm: drm_mm allocator to check |
| 715 | * |
| 716 | * Returns: |
| 717 | * True if the allocator is completely free, false if there's still a node |
| 718 | * allocated in it. |
| 719 | */ |
| 720 | bool drm_mm_clean(struct drm_mm * mm) |
| 721 | { |
| 722 | struct list_head *head = &mm->head_node.node_list; |
| 723 | |
| 724 | return (head->next->next == head); |
| 725 | } |
| 726 | EXPORT_SYMBOL(drm_mm_clean); |
| 727 | |
| 728 | /** |
| 729 | * drm_mm_init - initialize a drm-mm allocator |
| 730 | * @mm: the drm_mm structure to initialize |
| 731 | * @start: start of the range managed by @mm |
| 732 | * @size: end of the range managed by @mm |
| 733 | * |
| 734 | * Note that @mm must be cleared to 0 before calling this function. |
| 735 | */ |
| 736 | void drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size) |
| 737 | { |
| 738 | INIT_LIST_HEAD(&mm->hole_stack); |
| 739 | mm->scanned_blocks = 0; |
| 740 | |
| 741 | /* Clever trick to avoid a special case in the free hole tracking. */ |
| 742 | INIT_LIST_HEAD(&mm->head_node.node_list); |
| 743 | INIT_LIST_HEAD(&mm->head_node.hole_stack); |
| 744 | mm->head_node.hole_follows = 1; |
| 745 | mm->head_node.scanned_block = 0; |
| 746 | mm->head_node.scanned_prev_free = 0; |
| 747 | mm->head_node.scanned_next_free = 0; |
| 748 | mm->head_node.mm = mm; |
| 749 | mm->head_node.start = start + size; |
| 750 | mm->head_node.size = start - mm->head_node.start; |
| 751 | list_add_tail(&mm->head_node.hole_stack, &mm->hole_stack); |
| 752 | |
| 753 | mm->color_adjust = NULL; |
| 754 | } |
| 755 | EXPORT_SYMBOL(drm_mm_init); |
| 756 | |
| 757 | /** |
| 758 | * drm_mm_takedown - clean up a drm_mm allocator |
| 759 | * @mm: drm_mm allocator to clean up |
| 760 | * |
| 761 | * Note that it is a bug to call this function on an allocator which is not |
| 762 | * clean. |
| 763 | */ |
| 764 | void drm_mm_takedown(struct drm_mm * mm) |
| 765 | { |
| 766 | WARN(!list_empty(&mm->head_node.node_list), |
| 767 | "Memory manager not clean during takedown.\n" ); |
| 768 | } |
| 769 | EXPORT_SYMBOL(drm_mm_takedown); |
| 770 | |
| 771 | static unsigned long drm_mm_debug_hole(struct drm_mm_node *entry, |
| 772 | const char *prefix) |
| 773 | { |
| 774 | unsigned long hole_start, hole_end, hole_size; |
| 775 | |
| 776 | if (entry->hole_follows) { |
| 777 | hole_start = drm_mm_hole_node_start(entry); |
| 778 | hole_end = drm_mm_hole_node_end(entry); |
| 779 | hole_size = hole_end - hole_start; |
| 780 | printk(KERN_DEBUG "%s 0x%08lx-0x%08lx: %8lu: free\n" , |
| 781 | prefix, hole_start, hole_end, |
| 782 | hole_size); |
| 783 | return hole_size; |
| 784 | } |
| 785 | |
| 786 | return 0; |
| 787 | } |
| 788 | |
| 789 | /** |
| 790 | * drm_mm_debug_table - dump allocator state to dmesg |
| 791 | * @mm: drm_mm allocator to dump |
| 792 | * @prefix: prefix to use for dumping to dmesg |
| 793 | */ |
| 794 | void drm_mm_debug_table(struct drm_mm *mm, const char *prefix) |
| 795 | { |
| 796 | struct drm_mm_node *entry; |
| 797 | unsigned long total_used = 0, total_free = 0, total = 0; |
| 798 | |
| 799 | total_free += drm_mm_debug_hole(&mm->head_node, prefix); |
| 800 | |
| 801 | drm_mm_for_each_node(entry, mm) { |
| 802 | printk(KERN_DEBUG "%s 0x%08lx-0x%08lx: %8lu: used\n" , |
| 803 | prefix, entry->start, entry->start + entry->size, |
| 804 | entry->size); |
| 805 | total_used += entry->size; |
| 806 | total_free += drm_mm_debug_hole(entry, prefix); |
| 807 | } |
| 808 | total = total_free + total_used; |
| 809 | |
| 810 | printk(KERN_DEBUG "%s total: %lu, used %lu free %lu\n" , prefix, total, |
| 811 | total_used, total_free); |
| 812 | } |
| 813 | EXPORT_SYMBOL(drm_mm_debug_table); |
| 814 | |
| 815 | #if defined(CONFIG_DEBUG_FS) |
| 816 | static unsigned long drm_mm_dump_hole(struct seq_file *m, struct drm_mm_node *entry) |
| 817 | { |
| 818 | unsigned long hole_start, hole_end, hole_size; |
| 819 | |
| 820 | if (entry->hole_follows) { |
| 821 | hole_start = drm_mm_hole_node_start(entry); |
| 822 | hole_end = drm_mm_hole_node_end(entry); |
| 823 | hole_size = hole_end - hole_start; |
| 824 | seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: free\n" , |
| 825 | hole_start, hole_end, hole_size); |
| 826 | return hole_size; |
| 827 | } |
| 828 | |
| 829 | return 0; |
| 830 | } |
| 831 | |
| 832 | /** |
| 833 | * drm_mm_dump_table - dump allocator state to a seq_file |
| 834 | * @m: seq_file to dump to |
| 835 | * @mm: drm_mm allocator to dump |
| 836 | */ |
| 837 | int drm_mm_dump_table(struct seq_file *m, struct drm_mm *mm) |
| 838 | { |
| 839 | struct drm_mm_node *entry; |
| 840 | unsigned long total_used = 0, total_free = 0, total = 0; |
| 841 | |
| 842 | total_free += drm_mm_dump_hole(m, &mm->head_node); |
| 843 | |
| 844 | drm_mm_for_each_node(entry, mm) { |
| 845 | seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: used\n" , |
| 846 | entry->start, entry->start + entry->size, |
| 847 | entry->size); |
| 848 | total_used += entry->size; |
| 849 | total_free += drm_mm_dump_hole(m, entry); |
| 850 | } |
| 851 | total = total_free + total_used; |
| 852 | |
| 853 | seq_printf(m, "total: %lu, used %lu free %lu\n" , total, total_used, total_free); |
| 854 | return 0; |
| 855 | } |
| 856 | EXPORT_SYMBOL(drm_mm_dump_table); |
| 857 | #endif |
| 858 | |