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