sys/dev/drm/drm_mm.c

   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 #include <sys/cdefs.h>
  30 __FBSDID("$FreeBSD$");
  31
  32 /*
  33  * Generic simple memory manager implementation. Intended to be used as a base
  34  * class implementation for more advanced memory managers.
  35  *
  36  * Note that the algorithm used is quite simple and there might be substantial
  37  * performance gains if a smarter free list is implemented. Currently it is just an
  38  * unordered stack of free regions. This could easily be improved if an RB-tree
  39  * is used instead. At least if we expect heavy fragmentation.
  40  *
  41  * Aligned allocations can also see improvement.
  42  *
  43  * Authors:
  44  * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
  45  */
  46
  47 #include "dev/drm/drmP.h"
  48 #include "dev/drm/drm_mm.h"
  49
  50 #define MM_UNUSED_TARGET 4
  51
  52 unsigned long drm_mm_tail_space(struct drm_mm *mm)
  53 {
  54         struct list_head *tail_node;
  55         struct drm_mm_node *entry;
  56
  57         tail_node = mm->ml_entry.prev;
  58         entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
  59         if (!entry->free)
  60                 return 0;
  61
  62         return entry->size;
  63 }
  64
  65 int drm_mm_remove_space_from_tail(struct drm_mm *mm, unsigned long size)
  66 {
  67         struct list_head *tail_node;
  68         struct drm_mm_node *entry;
  69
  70         tail_node = mm->ml_entry.prev;
  71         entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
  72         if (!entry->free)
  73                 return -ENOMEM;
  74
  75         if (entry->size <= size)
  76                 return -ENOMEM;
  77
  78         entry->size -= size;
  79         return 0;
  80 }
  81
  82 static struct drm_mm_node *drm_mm_kmalloc(struct drm_mm *mm, int atomic)
  83 {
  84         struct drm_mm_node *child;
  85
  86         if (atomic)
  87                 child = malloc(sizeof(*child), DRM_MEM_MM, M_NOWAIT);
  88         else
  89                 child = malloc(sizeof(*child), DRM_MEM_MM, M_WAITOK);
  90
  91         if (unlikely(child == NULL)) {
  92                 mtx_lock(&mm->unused_lock);
  93                 if (list_empty(&mm->unused_nodes))
  94                         child = NULL;
  95                 else {
  96                         child =
  97                             list_entry(mm->unused_nodes.next,
  98                                        struct drm_mm_node, fl_entry);
  99                         list_del(&child->fl_entry);
 100                         --mm->num_unused;
 101                 }
 102                 mtx_unlock(&mm->unused_lock);
 103         }
 104         return child;
 105 }
 106
 107 int drm_mm_pre_get(struct drm_mm *mm)
 108 {
 109         struct drm_mm_node *node;
 110
 111         mtx_lock(&mm->unused_lock);
 112         while (mm->num_unused < MM_UNUSED_TARGET) {
 113                 mtx_unlock(&mm->unused_lock);
 114                 node = malloc(sizeof(*node), DRM_MEM_MM, M_WAITOK);
 115                 mtx_lock(&mm->unused_lock);
 116
 117                 if (unlikely(node == NULL)) {
 118                         int ret = (mm->num_unused < 2) ? -ENOMEM : 0;
 119                         mtx_unlock(&mm->unused_lock);
 120                         return ret;
 121                 }
 122                 ++mm->num_unused;
 123                 list_add_tail(&node->fl_entry, &mm->unused_nodes);
 124         }
 125         mtx_unlock(&mm->unused_lock);
 126         return 0;
 127 }
 128
 129 static int drm_mm_create_tail_node(struct drm_mm *mm,
 130                                    unsigned long start,
 131                                    unsigned long size, int atomic)
 132 {
 133         struct drm_mm_node *child;
 134
 135         child = drm_mm_kmalloc(mm, atomic);
 136         if (unlikely(child == NULL))
 137                 return -ENOMEM;
 138
 139         child->free = 1;
 140         child->size = size;
 141         child->start = start;
 142         child->mm = mm;
 143
 144         list_add_tail(&child->ml_entry, &mm->ml_entry);
 145         list_add_tail(&child->fl_entry, &mm->fl_entry);
 146
 147         return 0;
 148 }
 149
 150 int drm_mm_add_space_to_tail(struct drm_mm *mm, unsigned long size, int atomic)
 151 {
 152         struct list_head *tail_node;
 153         struct drm_mm_node *entry;
 154
 155         tail_node = mm->ml_entry.prev;
 156         entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
 157         if (!entry->free) {
 158                 return drm_mm_create_tail_node(mm, entry->start + entry->size,
 159                                                size, atomic);
 160         }
 161         entry->size += size;
 162         return 0;
 163 }
 164
 165 static struct drm_mm_node *drm_mm_split_at_start(struct drm_mm_node *parent,
 166                                                  unsigned long size,
 167                                                  int atomic)
 168 {
 169         struct drm_mm_node *child;
 170
 171         child = drm_mm_kmalloc(parent->mm, atomic);
 172         if (unlikely(child == NULL))
 173                 return NULL;
 174
 175         INIT_LIST_HEAD(&child->fl_entry);
 176
 177         child->free = 0;
 178         child->size = size;
 179         child->start = parent->start;
 180         child->mm = parent->mm;
 181
 182         list_add_tail(&child->ml_entry, &parent->ml_entry);
 183         INIT_LIST_HEAD(&child->fl_entry);
 184
 185         parent->size -= size;
 186         parent->start += size;
 187         return child;
 188 }
 189
 190
 191 struct drm_mm_node *drm_mm_get_block_generic(struct drm_mm_node *node,
 192                                              unsigned long size,
 193                                              unsigned alignment,
 194                                              int atomic)
 195 {
 196
 197         struct drm_mm_node *align_splitoff = NULL;
 198         unsigned tmp = 0;
 199
 200         if (alignment)
 201                 tmp = node->start % alignment;
 202
 203         if (tmp) {
 204                 align_splitoff =
 205                     drm_mm_split_at_start(node, alignment - tmp, atomic);
 206                 if (unlikely(align_splitoff == NULL))
 207                         return NULL;
 208         }
 209
 210         if (node->size == size) {
 211                 list_del_init(&node->fl_entry);
 212                 node->free = 0;
 213         } else {
 214                 node = drm_mm_split_at_start(node, size, atomic);
 215         }
 216
 217         if (align_splitoff)
 218                 drm_mm_put_block(align_splitoff);
 219
 220         return node;
 221 }
 222
 223 /*
 224  * Put a block. Merge with the previous and / or next block if they are free.
 225  * Otherwise add to the free stack.
 226  */
 227
 228 void drm_mm_put_block(struct drm_mm_node *cur)
 229 {
 230
 231         struct drm_mm *mm = cur->mm;
 232         struct list_head *cur_head = &cur->ml_entry;
 233         struct list_head *root_head = &mm->ml_entry;
 234         struct drm_mm_node *prev_node = NULL;
 235         struct drm_mm_node *next_node;
 236
 237         int merged = 0;
 238
 239         if (cur_head->prev != root_head) {
 240                 prev_node =
 241                     list_entry(cur_head->prev, struct drm_mm_node, ml_entry);
 242                 if (prev_node->free) {
 243                         prev_node->size += cur->size;
 244                         merged = 1;
 245                 }
 246         }
 247         if (cur_head->next != root_head) {
 248                 next_node =
 249                     list_entry(cur_head->next, struct drm_mm_node, ml_entry);
 250                 if (next_node->free) {
 251                         if (merged) {
 252                                 prev_node->size += next_node->size;
 253                                 list_del(&next_node->ml_entry);
 254                                 list_del(&next_node->fl_entry);
 255                                 if (mm->num_unused < MM_UNUSED_TARGET) {
 256                                         list_add(&next_node->fl_entry,
 257                                                  &mm->unused_nodes);
 258                                         ++mm->num_unused;
 259                                 } else
 260                                         free(next_node, DRM_MEM_MM);
 261                         } else {
 262                                 next_node->size += cur->size;
 263                                 next_node->start = cur->start;
 264                                 merged = 1;
 265                         }
 266                 }
 267         }
 268         if (!merged) {
 269                 cur->free = 1;
 270                 list_add(&cur->fl_entry, &mm->fl_entry);
 271         } else {
 272                 list_del(&cur->ml_entry);
 273                 if (mm->num_unused < MM_UNUSED_TARGET) {
 274                         list_add(&cur->fl_entry, &mm->unused_nodes);
 275                         ++mm->num_unused;
 276                 } else
 277                         free(cur, DRM_MEM_MM);
 278         }
 279 }
 280
 281 struct drm_mm_node *drm_mm_search_free(const struct drm_mm *mm,
 282                                        unsigned long size,
 283                                        unsigned alignment, int best_match)
 284 {
 285         struct list_head *list;
 286         const struct list_head *free_stack = &mm->fl_entry;
 287         struct drm_mm_node *entry;
 288         struct drm_mm_node *best;
 289         unsigned long best_size;
 290         unsigned wasted;
 291
 292         best = NULL;
 293         best_size = ~0UL;
 294
 295         list_for_each(list, free_stack) {
 296                 entry = list_entry(list, struct drm_mm_node, fl_entry);
 297                 wasted = 0;
 298
 299                 if (entry->size < size)
 300                         continue;
 301
 302                 if (alignment) {
 303                         register unsigned tmp = entry->start % alignment;
 304                         if (tmp)
 305                                 wasted += alignment - tmp;
 306                 }
 307
 308                 if (entry->size >= size + wasted) {
 309                         if (!best_match)
 310                                 return entry;
 311                         if (size < best_size) {
 312                                 best = entry;
 313                                 best_size = entry->size;
 314                         }
 315                 }
 316         }
 317
 318         return best;
 319 }
 320
 321 int drm_mm_clean(struct drm_mm * mm)
 322 {
 323         struct list_head *head = &mm->ml_entry;
 324
 325         return (head->next->next == head);
 326 }
 327
 328 int drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size)
 329 {
 330         INIT_LIST_HEAD(&mm->ml_entry);
 331         INIT_LIST_HEAD(&mm->fl_entry);
 332         INIT_LIST_HEAD(&mm->unused_nodes);
 333         mm->num_unused = 0;
 334         mtx_init(&mm->unused_lock, "drm_unused", NULL, MTX_DEF);
 335
 336         /* XXX This could be non-atomic but gets called from a locked path */
 337         return drm_mm_create_tail_node(mm, start, size, 1);
 338 }
 339
 340 void drm_mm_takedown(struct drm_mm * mm)
 341 {
 342         struct list_head *bnode = mm->fl_entry.next;
 343         struct drm_mm_node *entry;
 344         struct drm_mm_node *next;
 345
 346         entry = list_entry(bnode, struct drm_mm_node, fl_entry);
 347
 348         if (entry->ml_entry.next != &mm->ml_entry ||
 349             entry->fl_entry.next != &mm->fl_entry) {
 350                 DRM_ERROR("Memory manager not clean. Delaying takedown\n");
 351                 return;
 352         }
 353
 354         list_del(&entry->fl_entry);
 355         list_del(&entry->ml_entry);
 356         free(entry, DRM_MEM_MM);
 357
 358         mtx_lock(&mm->unused_lock);
 359         list_for_each_entry_safe(entry, next, &mm->unused_nodes, fl_entry) {
 360                 list_del(&entry->fl_entry);
 361                 free(entry, DRM_MEM_MM);
 362                 --mm->num_unused;
 363         }
 364         mtx_unlock(&mm->unused_lock);
 365
 366         mtx_destroy(&mm->unused_lock);
 367
 368         KASSERT(mm->num_unused == 0, ("num_unused != 0"));
 369 }