drivers/gpu/drm/ttm/ttm_page_alloc.c

   1 /*
   2  * Copyright (c) Red Hat Inc.
   3
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sub license,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the
  12  * next paragraph) shall be included in all copies or substantial portions
  13  * of the Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  *
  23  * Authors: Dave Airlie <airlied@redhat.com>
  24  *          Jerome Glisse <jglisse@redhat.com>
  25  *          Pauli Nieminen <suokkos@gmail.com>
  26  */
  27
  28 /* simple list based uncached page pool
  29  * - Pool collects resently freed pages for reuse
  30  * - Use page->lru to keep a free list
  31  * - doesn't track currently in use pages
  32  */
  33
  34 #define pr_fmt(fmt) "[TTM] " fmt
  35
  36 #include <linux/list.h>
  37 #include <linux/spinlock.h>
  38 #include <linux/highmem.h>
  39 #include <linux/mm_types.h>
  40 #include <linux/module.h>
  41 #include <linux/mm.h>
  42 #include <linux/seq_file.h> /* for seq_printf */
  43 #include <linux/slab.h>
  44 #include <linux/dma-mapping.h>
  45
  46 #include <linux/atomic.h>
  47
  48 #include <drm/ttm/ttm_bo_driver.h>
  49 #include <drm/ttm/ttm_page_alloc.h>
  50
  51 #if IS_ENABLED(CONFIG_AGP)
  52 #include <asm/agp.h>
  53 #endif
  54 #ifdef CONFIG_X86
  55 #include <asm/set_memory.h>
  56 #endif
  57
  58 #define NUM_PAGES_TO_ALLOC              (PAGE_SIZE/sizeof(struct page *))
  59 #define SMALL_ALLOCATION                16
  60 #define FREE_ALL_PAGES                  (~0U)
  61 /* times are in msecs */
  62 #define PAGE_FREE_INTERVAL              1000
  63
  64 /**
  65  * struct ttm_page_pool - Pool to reuse recently allocated uc/wc pages.
  66  *
  67  * @lock: Protects the shared pool from concurrnet access. Must be used with
  68  * irqsave/irqrestore variants because pool allocator maybe called from
  69  * delayed work.
  70  * @fill_lock: Prevent concurrent calls to fill.
  71  * @list: Pool of free uc/wc pages for fast reuse.
  72  * @gfp_flags: Flags to pass for alloc_page.
  73  * @npages: Number of pages in pool.
  74  */
  75 struct ttm_page_pool {
  76         spinlock_t              lock;
  77         bool                    fill_lock;
  78         struct list_head        list;
  79         gfp_t                   gfp_flags;
  80         unsigned                npages;
  81         char                    *name;
  82         unsigned long           nfrees;
  83         unsigned long           nrefills;
  84 };
  85
  86 /**
  87  * Limits for the pool. They are handled without locks because only place where
  88  * they may change is in sysfs store. They won't have immediate effect anyway
  89  * so forcing serialization to access them is pointless.
  90  */
  91
  92 struct ttm_pool_opts {
  93         unsigned        alloc_size;
  94         unsigned        max_size;
  95         unsigned        small;
  96 };
  97
  98 #define NUM_POOLS 4
  99
 100 /**
 101  * struct ttm_pool_manager - Holds memory pools for fst allocation
 102  *
 103  * Manager is read only object for pool code so it doesn't need locking.
 104  *
 105  * @free_interval: minimum number of jiffies between freeing pages from pool.
 106  * @page_alloc_inited: reference counting for pool allocation.
 107  * @work: Work that is used to shrink the pool. Work is only run when there is
 108  * some pages to free.
 109  * @small_allocation: Limit in number of pages what is small allocation.
 110  *
 111  * @pools: All pool objects in use.
 112  **/
 113 struct ttm_pool_manager {
 114         struct kobject          kobj;
 115         struct shrinker         mm_shrink;
 116         struct ttm_pool_opts    options;
 117
 118         union {
 119                 struct ttm_page_pool    pools[NUM_POOLS];
 120                 struct {
 121                         struct ttm_page_pool    wc_pool;
 122                         struct ttm_page_pool    uc_pool;
 123                         struct ttm_page_pool    wc_pool_dma32;
 124                         struct ttm_page_pool    uc_pool_dma32;
 125                 } ;
 126         };
 127 };
 128
 129 static struct attribute ttm_page_pool_max = {
 130         .name = "pool_max_size",
 131         .mode = S_IRUGO | S_IWUSR
 132 };
 133 static struct attribute ttm_page_pool_small = {
 134         .name = "pool_small_allocation",
 135         .mode = S_IRUGO | S_IWUSR
 136 };
 137 static struct attribute ttm_page_pool_alloc_size = {
 138         .name = "pool_allocation_size",
 139         .mode = S_IRUGO | S_IWUSR
 140 };
 141
 142 static struct attribute *ttm_pool_attrs[] = {
 143         &ttm_page_pool_max,
 144         &ttm_page_pool_small,
 145         &ttm_page_pool_alloc_size,
 146         NULL
 147 };
 148
 149 static void ttm_pool_kobj_release(struct kobject *kobj)
 150 {
 151         struct ttm_pool_manager *m =
 152                 container_of(kobj, struct ttm_pool_manager, kobj);
 153         kfree(m);
 154 }
 155
 156 static ssize_t ttm_pool_store(struct kobject *kobj,
 157                 struct attribute *attr, const char *buffer, size_t size)
 158 {
 159         struct ttm_pool_manager *m =
 160                 container_of(kobj, struct ttm_pool_manager, kobj);
 161         int chars;
 162         unsigned val;
 163         chars = sscanf(buffer, "%u", &val);
 164         if (chars == 0)
 165                 return size;
 166
 167         /* Convert kb to number of pages */
 168         val = val / (PAGE_SIZE >> 10);
 169
 170         if (attr == &ttm_page_pool_max)
 171                 m->options.max_size = val;
 172         else if (attr == &ttm_page_pool_small)
 173                 m->options.small = val;
 174         else if (attr == &ttm_page_pool_alloc_size) {
 175                 if (val > NUM_PAGES_TO_ALLOC*8) {
 176                         pr_err("Setting allocation size to %lu is not allowed. Recommended size is %lu\n",
 177                                NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 7),
 178                                NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 10));
 179                         return size;
 180                 } else if (val > NUM_PAGES_TO_ALLOC) {
 181                         pr_warn("Setting allocation size to larger than %lu is not recommended\n",
 182                                 NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 10));
 183                 }
 184                 m->options.alloc_size = val;
 185         }
 186
 187         return size;
 188 }
 189
 190 static ssize_t ttm_pool_show(struct kobject *kobj,
 191                 struct attribute *attr, char *buffer)
 192 {
 193         struct ttm_pool_manager *m =
 194                 container_of(kobj, struct ttm_pool_manager, kobj);
 195         unsigned val = 0;
 196
 197         if (attr == &ttm_page_pool_max)
 198                 val = m->options.max_size;
 199         else if (attr == &ttm_page_pool_small)
 200                 val = m->options.small;
 201         else if (attr == &ttm_page_pool_alloc_size)
 202                 val = m->options.alloc_size;
 203
 204         val = val * (PAGE_SIZE >> 10);
 205
 206         return snprintf(buffer, PAGE_SIZE, "%u\n", val);
 207 }
 208
 209 static const struct sysfs_ops ttm_pool_sysfs_ops = {
 210         .show = &ttm_pool_show,
 211         .store = &ttm_pool_store,
 212 };
 213
 214 static struct kobj_type ttm_pool_kobj_type = {
 215         .release = &ttm_pool_kobj_release,
 216         .sysfs_ops = &ttm_pool_sysfs_ops,
 217         .default_attrs = ttm_pool_attrs,
 218 };
 219
 220 static struct ttm_pool_manager *_manager;
 221
 222 #ifndef CONFIG_X86
 223 static int set_pages_array_wb(struct page **pages, int addrinarray)
 224 {
 225 #if IS_ENABLED(CONFIG_AGP)
 226         int i;
 227
 228         for (i = 0; i < addrinarray; i++)
 229                 unmap_page_from_agp(pages[i]);
 230 #endif
 231         return 0;
 232 }
 233
 234 static int set_pages_array_wc(struct page **pages, int addrinarray)
 235 {
 236 #if IS_ENABLED(CONFIG_AGP)
 237         int i;
 238
 239         for (i = 0; i < addrinarray; i++)
 240                 map_page_into_agp(pages[i]);
 241 #endif
 242         return 0;
 243 }
 244
 245 static int set_pages_array_uc(struct page **pages, int addrinarray)
 246 {
 247 #if IS_ENABLED(CONFIG_AGP)
 248         int i;
 249
 250         for (i = 0; i < addrinarray; i++)
 251                 map_page_into_agp(pages[i]);
 252 #endif
 253         return 0;
 254 }
 255 #endif
 256
 257 /**
 258  * Select the right pool or requested caching state and ttm flags. */
 259 static struct ttm_page_pool *ttm_get_pool(int flags,
 260                 enum ttm_caching_state cstate)
 261 {
 262         int pool_index;
 263
 264         if (cstate == tt_cached)
 265                 return NULL;
 266
 267         if (cstate == tt_wc)
 268                 pool_index = 0x0;
 269         else
 270                 pool_index = 0x1;
 271
 272         if (flags & TTM_PAGE_FLAG_DMA32)
 273                 pool_index |= 0x2;
 274
 275         return &_manager->pools[pool_index];
 276 }
 277
 278 /* set memory back to wb and free the pages. */
 279 static void ttm_pages_put(struct page *pages[], unsigned npages)
 280 {
 281         unsigned i;
 282         if (set_pages_array_wb(pages, npages))
 283                 pr_err("Failed to set %d pages to wb!\n", npages);
 284         for (i = 0; i < npages; ++i)
 285                 __free_page(pages[i]);
 286 }
 287
 288 static void ttm_pool_update_free_locked(struct ttm_page_pool *pool,
 289                 unsigned freed_pages)
 290 {
 291         pool->npages -= freed_pages;
 292         pool->nfrees += freed_pages;
 293 }
 294
 295 /**
 296  * Free pages from pool.
 297  *
 298  * To prevent hogging the ttm_swap process we only free NUM_PAGES_TO_ALLOC
 299  * number of pages in one go.
 300  *
 301  * @pool: to free the pages from
 302  * @free_all: If set to true will free all pages in pool
 303  * @use_static: Safe to use static buffer
 304  **/
 305 static int ttm_page_pool_free(struct ttm_page_pool *pool, unsigned nr_free,
 306                               bool use_static)
 307 {
 308         static struct page *static_buf[NUM_PAGES_TO_ALLOC];
 309         unsigned long irq_flags;
 310         struct page *p;
 311         struct page **pages_to_free;
 312         unsigned freed_pages = 0,
 313                  npages_to_free = nr_free;
 314
 315         if (NUM_PAGES_TO_ALLOC < nr_free)
 316                 npages_to_free = NUM_PAGES_TO_ALLOC;
 317
 318         if (use_static)
 319                 pages_to_free = static_buf;
 320         else
 321                 pages_to_free = kmalloc(npages_to_free * sizeof(struct page *),
 322                                         GFP_KERNEL);
 323         if (!pages_to_free) {
 324                 pr_err("Failed to allocate memory for pool free operation\n");
 325                 return 0;
 326         }
 327
 328 restart:
 329         spin_lock_irqsave(&pool->lock, irq_flags);
 330
 331         list_for_each_entry_reverse(p, &pool->list, lru) {
 332                 if (freed_pages >= npages_to_free)
 333                         break;
 334
 335                 pages_to_free[freed_pages++] = p;
 336                 /* We can only remove NUM_PAGES_TO_ALLOC at a time. */
 337                 if (freed_pages >= NUM_PAGES_TO_ALLOC) {
 338                         /* remove range of pages from the pool */
 339                         __list_del(p->lru.prev, &pool->list);
 340
 341                         ttm_pool_update_free_locked(pool, freed_pages);
 342                         /**
 343                          * Because changing page caching is costly
 344                          * we unlock the pool to prevent stalling.
 345                          */
 346                         spin_unlock_irqrestore(&pool->lock, irq_flags);
 347
 348                         ttm_pages_put(pages_to_free, freed_pages);
 349                         if (likely(nr_free != FREE_ALL_PAGES))
 350                                 nr_free -= freed_pages;
 351
 352                         if (NUM_PAGES_TO_ALLOC >= nr_free)
 353                                 npages_to_free = nr_free;
 354                         else
 355                                 npages_to_free = NUM_PAGES_TO_ALLOC;
 356
 357                         freed_pages = 0;
 358
 359                         /* free all so restart the processing */
 360                         if (nr_free)
 361                                 goto restart;
 362
 363                         /* Not allowed to fall through or break because
 364                          * following context is inside spinlock while we are
 365                          * outside here.
 366                          */
 367                         goto out;
 368
 369                 }
 370         }
 371
 372         /* remove range of pages from the pool */
 373         if (freed_pages) {
 374                 __list_del(&p->lru, &pool->list);
 375
 376                 ttm_pool_update_free_locked(pool, freed_pages);
 377                 nr_free -= freed_pages;
 378         }
 379
 380         spin_unlock_irqrestore(&pool->lock, irq_flags);
 381
 382         if (freed_pages)
 383                 ttm_pages_put(pages_to_free, freed_pages);
 384 out:
 385         if (pages_to_free != static_buf)
 386                 kfree(pages_to_free);
 387         return nr_free;
 388 }
 389
 390 /**
 391  * Callback for mm to request pool to reduce number of page held.
 392  *
 393  * XXX: (dchinner) Deadlock warning!
 394  *
 395  * This code is crying out for a shrinker per pool....
 396  */
 397 static unsigned long
 398 ttm_pool_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
 399 {
 400         static DEFINE_MUTEX(lock);
 401         static unsigned start_pool;
 402         unsigned i;
 403         unsigned pool_offset;
 404         struct ttm_page_pool *pool;
 405         int shrink_pages = sc->nr_to_scan;
 406         unsigned long freed = 0;
 407
 408         if (!mutex_trylock(&lock))
 409                 return SHRINK_STOP;
 410         pool_offset = ++start_pool % NUM_POOLS;
 411         /* select start pool in round robin fashion */
 412         for (i = 0; i < NUM_POOLS; ++i) {
 413                 unsigned nr_free = shrink_pages;
 414                 if (shrink_pages == 0)
 415                         break;
 416                 pool = &_manager->pools[(i + pool_offset)%NUM_POOLS];
 417                 /* OK to use static buffer since global mutex is held. */
 418                 shrink_pages = ttm_page_pool_free(pool, nr_free, true);
 419                 freed += nr_free - shrink_pages;
 420         }
 421         mutex_unlock(&lock);
 422         return freed;
 423 }
 424
 425
 426 static unsigned long
 427 ttm_pool_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
 428 {
 429         unsigned i;
 430         unsigned long count = 0;
 431
 432         for (i = 0; i < NUM_POOLS; ++i)
 433                 count += _manager->pools[i].npages;
 434
 435         return count;
 436 }
 437
 438 static void ttm_pool_mm_shrink_init(struct ttm_pool_manager *manager)
 439 {
 440         manager->mm_shrink.count_objects = ttm_pool_shrink_count;
 441         manager->mm_shrink.scan_objects = ttm_pool_shrink_scan;
 442         manager->mm_shrink.seeks = 1;
 443         register_shrinker(&manager->mm_shrink);
 444 }
 445
 446 static void ttm_pool_mm_shrink_fini(struct ttm_pool_manager *manager)
 447 {
 448         unregister_shrinker(&manager->mm_shrink);
 449 }
 450
 451 static int ttm_set_pages_caching(struct page **pages,
 452                 enum ttm_caching_state cstate, unsigned cpages)
 453 {
 454         int r = 0;
 455         /* Set page caching */
 456         switch (cstate) {
 457         case tt_uncached:
 458                 r = set_pages_array_uc(pages, cpages);
 459                 if (r)
 460                         pr_err("Failed to set %d pages to uc!\n", cpages);
 461                 break;
 462         case tt_wc:
 463                 r = set_pages_array_wc(pages, cpages);
 464                 if (r)
 465                         pr_err("Failed to set %d pages to wc!\n", cpages);
 466                 break;
 467         default:
 468                 break;
 469         }
 470         return r;
 471 }
 472
 473 /**
 474  * Free pages the pages that failed to change the caching state. If there is
 475  * any pages that have changed their caching state already put them to the
 476  * pool.
 477  */
 478 static void ttm_handle_caching_state_failure(struct list_head *pages,
 479                 int ttm_flags, enum ttm_caching_state cstate,
 480                 struct page **failed_pages, unsigned cpages)
 481 {
 482         unsigned i;
 483         /* Failed pages have to be freed */
 484         for (i = 0; i < cpages; ++i) {
 485                 list_del(&failed_pages[i]->lru);
 486                 __free_page(failed_pages[i]);
 487         }
 488 }
 489
 490 /**
 491  * Allocate new pages with correct caching.
 492  *
 493  * This function is reentrant if caller updates count depending on number of
 494  * pages returned in pages array.
 495  */
 496 static int ttm_alloc_new_pages(struct list_head *pages, gfp_t gfp_flags,
 497                 int ttm_flags, enum ttm_caching_state cstate, unsigned count)
 498 {
 499         struct page **caching_array;
 500         struct page *p;
 501         int r = 0;
 502         unsigned i, cpages;
 503         unsigned max_cpages = min(count,
 504                         (unsigned)(PAGE_SIZE/sizeof(struct page *)));
 505
 506         /* allocate array for page caching change */
 507         caching_array = kmalloc(max_cpages*sizeof(struct page *), GFP_KERNEL);
 508
 509         if (!caching_array) {
 510                 pr_err("Unable to allocate table for new pages\n");
 511                 return -ENOMEM;
 512         }
 513
 514         for (i = 0, cpages = 0; i < count; ++i) {
 515                 p = alloc_page(gfp_flags);
 516
 517                 if (!p) {
 518                         pr_err("Unable to get page %u\n", i);
 519
 520                         /* store already allocated pages in the pool after
 521                          * setting the caching state */
 522                         if (cpages) {
 523                                 r = ttm_set_pages_caching(caching_array,
 524                                                           cstate, cpages);
 525                                 if (r)
 526                                         ttm_handle_caching_state_failure(pages,
 527                                                 ttm_flags, cstate,
 528                                                 caching_array, cpages);
 529                         }
 530                         r = -ENOMEM;
 531                         goto out;
 532                 }
 533
 534 #ifdef CONFIG_HIGHMEM
 535                 /* gfp flags of highmem page should never be dma32 so we
 536                  * we should be fine in such case
 537                  */
 538                 if (!PageHighMem(p))
 539 #endif
 540                 {
 541                         caching_array[cpages++] = p;
 542                         if (cpages == max_cpages) {
 543
 544                                 r = ttm_set_pages_caching(caching_array,
 545                                                 cstate, cpages);
 546                                 if (r) {
 547                                         ttm_handle_caching_state_failure(pages,
 548                                                 ttm_flags, cstate,
 549                                                 caching_array, cpages);
 550                                         goto out;
 551                                 }
 552                                 cpages = 0;
 553                         }
 554                 }
 555
 556                 list_add(&p->lru, pages);
 557         }
 558
 559         if (cpages) {
 560                 r = ttm_set_pages_caching(caching_array, cstate, cpages);
 561                 if (r)
 562                         ttm_handle_caching_state_failure(pages,
 563                                         ttm_flags, cstate,
 564                                         caching_array, cpages);
 565         }
 566 out:
 567         kfree(caching_array);
 568
 569         return r;
 570 }
 571
 572 /**
 573  * Fill the given pool if there aren't enough pages and the requested number of
 574  * pages is small.
 575  */
 576 static void ttm_page_pool_fill_locked(struct ttm_page_pool *pool,
 577                 int ttm_flags, enum ttm_caching_state cstate, unsigned count,
 578                 unsigned long *irq_flags)
 579 {
 580         struct page *p;
 581         int r;
 582         unsigned cpages = 0;
 583         /**
 584          * Only allow one pool fill operation at a time.
 585          * If pool doesn't have enough pages for the allocation new pages are
 586          * allocated from outside of pool.
 587          */
 588         if (pool->fill_lock)
 589                 return;
 590
 591         pool->fill_lock = true;
 592
 593         /* If allocation request is small and there are not enough
 594          * pages in a pool we fill the pool up first. */
 595         if (count < _manager->options.small
 596                 && count > pool->npages) {
 597                 struct list_head new_pages;
 598                 unsigned alloc_size = _manager->options.alloc_size;
 599
 600                 /**
 601                  * Can't change page caching if in irqsave context. We have to
 602                  * drop the pool->lock.
 603                  */
 604                 spin_unlock_irqrestore(&pool->lock, *irq_flags);
 605
 606                 INIT_LIST_HEAD(&new_pages);
 607                 r = ttm_alloc_new_pages(&new_pages, pool->gfp_flags, ttm_flags,
 608                                 cstate, alloc_size);
 609                 spin_lock_irqsave(&pool->lock, *irq_flags);
 610
 611                 if (!r) {
 612                         list_splice(&new_pages, &pool->list);
 613                         ++pool->nrefills;
 614                         pool->npages += alloc_size;
 615                 } else {
 616                         pr_err("Failed to fill pool (%p)\n", pool);
 617                         /* If we have any pages left put them to the pool. */
 618                         list_for_each_entry(p, &pool->list, lru) {
 619                                 ++cpages;
 620                         }
 621                         list_splice(&new_pages, &pool->list);
 622                         pool->npages += cpages;
 623                 }
 624
 625         }
 626         pool->fill_lock = false;
 627 }
 628
 629 /**
 630  * Cut 'count' number of pages from the pool and put them on the return list.
 631  *
 632  * @return count of pages still required to fulfill the request.
 633  */
 634 static unsigned ttm_page_pool_get_pages(struct ttm_page_pool *pool,
 635                                         struct list_head *pages,
 636                                         int ttm_flags,
 637                                         enum ttm_caching_state cstate,
 638                                         unsigned count)
 639 {
 640         unsigned long irq_flags;
 641         struct list_head *p;
 642         unsigned i;
 643
 644         spin_lock_irqsave(&pool->lock, irq_flags);
 645         ttm_page_pool_fill_locked(pool, ttm_flags, cstate, count, &irq_flags);
 646
 647         if (count >= pool->npages) {
 648                 /* take all pages from the pool */
 649                 list_splice_init(&pool->list, pages);
 650                 count -= pool->npages;
 651                 pool->npages = 0;
 652                 goto out;
 653         }
 654         /* find the last pages to include for requested number of pages. Split
 655          * pool to begin and halve it to reduce search space. */
 656         if (count <= pool->npages/2) {
 657                 i = 0;
 658                 list_for_each(p, &pool->list) {
 659                         if (++i == count)
 660                                 break;
 661                 }
 662         } else {
 663                 i = pool->npages + 1;
 664                 list_for_each_prev(p, &pool->list) {
 665                         if (--i == count)
 666                                 break;
 667                 }
 668         }
 669         /* Cut 'count' number of pages from the pool */
 670         list_cut_position(pages, &pool->list, p);
 671         pool->npages -= count;
 672         count = 0;
 673 out:
 674         spin_unlock_irqrestore(&pool->lock, irq_flags);
 675         return count;
 676 }
 677
 678 /* Put all pages in pages list to correct pool to wait for reuse */
 679 static void ttm_put_pages(struct page **pages, unsigned npages, int flags,
 680                           enum ttm_caching_state cstate)
 681 {
 682         unsigned long irq_flags;
 683         struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
 684         unsigned i;
 685
 686         if (pool == NULL) {
 687                 /* No pool for this memory type so free the pages */
 688                 for (i = 0; i < npages; i++) {
 689                         if (pages[i]) {
 690                                 if (page_count(pages[i]) != 1)
 691                                         pr_err("Erroneous page count. Leaking pages.\n");
 692                                 __free_page(pages[i]);
 693                                 pages[i] = NULL;
 694                         }
 695                 }
 696                 return;
 697         }
 698
 699         spin_lock_irqsave(&pool->lock, irq_flags);
 700         for (i = 0; i < npages; i++) {
 701                 if (pages[i]) {
 702                         if (page_count(pages[i]) != 1)
 703                                 pr_err("Erroneous page count. Leaking pages.\n");
 704                         list_add_tail(&pages[i]->lru, &pool->list);
 705                         pages[i] = NULL;
 706                         pool->npages++;
 707                 }
 708         }
 709         /* Check that we don't go over the pool limit */
 710         npages = 0;
 711         if (pool->npages > _manager->options.max_size) {
 712                 npages = pool->npages - _manager->options.max_size;
 713                 /* free at least NUM_PAGES_TO_ALLOC number of pages
 714                  * to reduce calls to set_memory_wb */
 715                 if (npages < NUM_PAGES_TO_ALLOC)
 716                         npages = NUM_PAGES_TO_ALLOC;
 717         }
 718         spin_unlock_irqrestore(&pool->lock, irq_flags);
 719         if (npages)
 720                 ttm_page_pool_free(pool, npages, false);
 721 }
 722
 723 /*
 724  * On success pages list will hold count number of correctly
 725  * cached pages.
 726  */
 727 static int ttm_get_pages(struct page **pages, unsigned npages, int flags,
 728                          enum ttm_caching_state cstate)
 729 {
 730         struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
 731         struct list_head plist;
 732         struct page *p = NULL;
 733         gfp_t gfp_flags = GFP_USER;
 734         unsigned count;
 735         int r;
 736
 737         /* set zero flag for page allocation if required */
 738         if (flags & TTM_PAGE_FLAG_ZERO_ALLOC)
 739                 gfp_flags |= __GFP_ZERO;
 740
 741         /* No pool for cached pages */
 742         if (pool == NULL) {
 743                 if (flags & TTM_PAGE_FLAG_DMA32)
 744                         gfp_flags |= GFP_DMA32;
 745                 else
 746                         gfp_flags |= GFP_HIGHUSER;
 747
 748                 for (r = 0; r < npages; ++r) {
 749                         p = alloc_page(gfp_flags);
 750                         if (!p) {
 751
 752                                 pr_err("Unable to allocate page\n");
 753                                 return -ENOMEM;
 754                         }
 755
 756                         pages[r] = p;
 757                 }
 758                 return 0;
 759         }
 760
 761         /* combine zero flag to pool flags */
 762         gfp_flags |= pool->gfp_flags;
 763
 764         /* First we take pages from the pool */
 765         INIT_LIST_HEAD(&plist);
 766         npages = ttm_page_pool_get_pages(pool, &plist, flags, cstate, npages);
 767         count = 0;
 768         list_for_each_entry(p, &plist, lru) {
 769                 pages[count++] = p;
 770         }
 771
 772         /* clear the pages coming from the pool if requested */
 773         if (flags & TTM_PAGE_FLAG_ZERO_ALLOC) {
 774                 list_for_each_entry(p, &plist, lru) {
 775                         if (PageHighMem(p))
 776                                 clear_highpage(p);
 777                         else
 778                                 clear_page(page_address(p));
 779                 }
 780         }
 781
 782         /* If pool didn't have enough pages allocate new one. */
 783         if (npages > 0) {
 784                 /* ttm_alloc_new_pages doesn't reference pool so we can run
 785                  * multiple requests in parallel.
 786                  **/
 787                 INIT_LIST_HEAD(&plist);
 788                 r = ttm_alloc_new_pages(&plist, gfp_flags, flags, cstate, npages);
 789                 list_for_each_entry(p, &plist, lru) {
 790                         pages[count++] = p;
 791                 }
 792                 if (r) {
 793                         /* If there is any pages in the list put them back to
 794                          * the pool. */
 795                         pr_err("Failed to allocate extra pages for large request\n");
 796                         ttm_put_pages(pages, count, flags, cstate);
 797                         return r;
 798                 }
 799         }
 800
 801         return 0;
 802 }
 803
 804 static void ttm_page_pool_init_locked(struct ttm_page_pool *pool, gfp_t flags,
 805                 char *name)
 806 {
 807         spin_lock_init(&pool->lock);
 808         pool->fill_lock = false;
 809         INIT_LIST_HEAD(&pool->list);
 810         pool->npages = pool->nfrees = 0;
 811         pool->gfp_flags = flags;
 812         pool->name = name;
 813 }
 814
 815 int ttm_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)
 816 {
 817         int ret;
 818
 819         WARN_ON(_manager);
 820
 821         pr_info("Initializing pool allocator\n");
 822
 823         _manager = kzalloc(sizeof(*_manager), GFP_KERNEL);
 824
 825         ttm_page_pool_init_locked(&_manager->wc_pool, GFP_HIGHUSER, "wc");
 826
 827         ttm_page_pool_init_locked(&_manager->uc_pool, GFP_HIGHUSER, "uc");
 828
 829         ttm_page_pool_init_locked(&_manager->wc_pool_dma32,
 830                                   GFP_USER | GFP_DMA32, "wc dma");
 831
 832         ttm_page_pool_init_locked(&_manager->uc_pool_dma32,
 833                                   GFP_USER | GFP_DMA32, "uc dma");
 834
 835         _manager->options.max_size = max_pages;
 836         _manager->options.small = SMALL_ALLOCATION;
 837         _manager->options.alloc_size = NUM_PAGES_TO_ALLOC;
 838
 839         ret = kobject_init_and_add(&_manager->kobj, &ttm_pool_kobj_type,
 840                                    &glob->kobj, "pool");
 841         if (unlikely(ret != 0)) {
 842                 kobject_put(&_manager->kobj);
 843                 _manager = NULL;
 844                 return ret;
 845         }
 846
 847         ttm_pool_mm_shrink_init(_manager);
 848
 849         return 0;
 850 }
 851
 852 void ttm_page_alloc_fini(void)
 853 {
 854         int i;
 855
 856         pr_info("Finalizing pool allocator\n");
 857         ttm_pool_mm_shrink_fini(_manager);
 858
 859         /* OK to use static buffer since global mutex is no longer used. */
 860         for (i = 0; i < NUM_POOLS; ++i)
 861                 ttm_page_pool_free(&_manager->pools[i], FREE_ALL_PAGES, true);
 862
 863         kobject_put(&_manager->kobj);
 864         _manager = NULL;
 865 }
 866
 867 int ttm_pool_populate(struct ttm_tt *ttm)
 868 {
 869         struct ttm_mem_global *mem_glob = ttm->glob->mem_glob;
 870         unsigned i;
 871         int ret;
 872
 873         if (ttm->state != tt_unpopulated)
 874                 return 0;
 875
 876         for (i = 0; i < ttm->num_pages; ++i) {
 877                 ret = ttm_get_pages(&ttm->pages[i], 1,
 878                                     ttm->page_flags,
 879                                     ttm->caching_state);
 880                 if (ret != 0) {
 881                         ttm_pool_unpopulate(ttm);
 882                         return -ENOMEM;
 883                 }
 884
 885                 ret = ttm_mem_global_alloc_page(mem_glob, ttm->pages[i],
 886                                                 false, false);
 887                 if (unlikely(ret != 0)) {
 888                         ttm_pool_unpopulate(ttm);
 889                         return -ENOMEM;
 890                 }
 891         }
 892
 893         if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
 894                 ret = ttm_tt_swapin(ttm);
 895                 if (unlikely(ret != 0)) {
 896                         ttm_pool_unpopulate(ttm);
 897                         return ret;
 898                 }
 899         }
 900
 901         ttm->state = tt_unbound;
 902         return 0;
 903 }
 904 EXPORT_SYMBOL(ttm_pool_populate);
 905
 906 void ttm_pool_unpopulate(struct ttm_tt *ttm)
 907 {
 908         unsigned i;
 909
 910         for (i = 0; i < ttm->num_pages; ++i) {
 911                 if (ttm->pages[i]) {
 912                         ttm_mem_global_free_page(ttm->glob->mem_glob,
 913                                                  ttm->pages[i]);
 914                         ttm_put_pages(&ttm->pages[i], 1,
 915                                       ttm->page_flags,
 916                                       ttm->caching_state);
 917                 }
 918         }
 919         ttm->state = tt_unpopulated;
 920 }
 921 EXPORT_SYMBOL(ttm_pool_unpopulate);
 922
 923 int ttm_page_alloc_debugfs(struct seq_file *m, void *data)
 924 {
 925         struct ttm_page_pool *p;
 926         unsigned i;
 927         char *h[] = {"pool", "refills", "pages freed", "size"};
 928         if (!_manager) {
 929                 seq_printf(m, "No pool allocator running.\n");
 930                 return 0;
 931         }
 932         seq_printf(m, "%6s %12s %13s %8s\n",
 933                         h[0], h[1], h[2], h[3]);
 934         for (i = 0; i < NUM_POOLS; ++i) {
 935                 p = &_manager->pools[i];
 936
 937                 seq_printf(m, "%6s %12ld %13ld %8d\n",
 938                                 p->name, p->nrefills,
 939                                 p->nfrees, p->npages);
 940         }
 941         return 0;
 942 }
 943 EXPORT_SYMBOL(ttm_page_alloc_debugfs);