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 #ifdef TTM_HAS_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 #ifdef TTM_HAS_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 #ifdef TTM_HAS_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 #ifdef TTM_HAS_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  **/
 301 static int ttm_page_pool_free(struct ttm_page_pool *pool, unsigned nr_free)
 302 {
 303         unsigned long irq_flags;
 304         struct page *p;
 305         struct page **pages_to_free;
 306         unsigned freed_pages = 0,
 307                  npages_to_free = nr_free;
 308
 309         if (NUM_PAGES_TO_ALLOC < nr_free)
 310                 npages_to_free = NUM_PAGES_TO_ALLOC;
 311
 312         pages_to_free = kmalloc(npages_to_free * sizeof(struct page *),
 313                         GFP_KERNEL);
 314         if (!pages_to_free) {
 315                 pr_err("Failed to allocate memory for pool free operation\n");
 316                 return 0;
 317         }
 318
 319 restart:
 320         spin_lock_irqsave(&pool->lock, irq_flags);
 321
 322         list_for_each_entry_reverse(p, &pool->list, lru) {
 323                 if (freed_pages >= npages_to_free)
 324                         break;
 325
 326                 pages_to_free[freed_pages++] = p;
 327                 /* We can only remove NUM_PAGES_TO_ALLOC at a time. */
 328                 if (freed_pages >= NUM_PAGES_TO_ALLOC) {
 329                         /* remove range of pages from the pool */
 330                         __list_del(p->lru.prev, &pool->list);
 331
 332                         ttm_pool_update_free_locked(pool, freed_pages);
 333                         /**
 334                          * Because changing page caching is costly
 335                          * we unlock the pool to prevent stalling.
 336                          */
 337                         spin_unlock_irqrestore(&pool->lock, irq_flags);
 338
 339                         ttm_pages_put(pages_to_free, freed_pages);
 340                         if (likely(nr_free != FREE_ALL_PAGES))
 341                                 nr_free -= freed_pages;
 342
 343                         if (NUM_PAGES_TO_ALLOC >= nr_free)
 344                                 npages_to_free = nr_free;
 345                         else
 346                                 npages_to_free = NUM_PAGES_TO_ALLOC;
 347
 348                         freed_pages = 0;
 349
 350                         /* free all so restart the processing */
 351                         if (nr_free)
 352                                 goto restart;
 353
 354                         /* Not allowed to fall through or break because
 355                          * following context is inside spinlock while we are
 356                          * outside here.
 357                          */
 358                         goto out;
 359
 360                 }
 361         }
 362
 363         /* remove range of pages from the pool */
 364         if (freed_pages) {
 365                 __list_del(&p->lru, &pool->list);
 366
 367                 ttm_pool_update_free_locked(pool, freed_pages);
 368                 nr_free -= freed_pages;
 369         }
 370
 371         spin_unlock_irqrestore(&pool->lock, irq_flags);
 372
 373         if (freed_pages)
 374                 ttm_pages_put(pages_to_free, freed_pages);
 375 out:
 376         kfree(pages_to_free);
 377         return nr_free;
 378 }
 379
 380 /**
 381  * Callback for mm to request pool to reduce number of page held.
 382  *
 383  * XXX: (dchinner) Deadlock warning!
 384  *
 385  * ttm_page_pool_free() does memory allocation using GFP_KERNEL.  that means
 386  * this can deadlock when called a sc->gfp_mask that is not equal to
 387  * GFP_KERNEL.
 388  *
 389  * This code is crying out for a shrinker per pool....
 390  */
 391 static unsigned long
 392 ttm_pool_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
 393 {
 394         static atomic_t start_pool = ATOMIC_INIT(0);
 395         unsigned i;
 396         unsigned pool_offset = atomic_add_return(1, &start_pool);
 397         struct ttm_page_pool *pool;
 398         int shrink_pages = sc->nr_to_scan;
 399         unsigned long freed = 0;
 400
 401         pool_offset = pool_offset % NUM_POOLS;
 402         /* select start pool in round robin fashion */
 403         for (i = 0; i < NUM_POOLS; ++i) {
 404                 unsigned nr_free = shrink_pages;
 405                 if (shrink_pages == 0)
 406                         break;
 407                 pool = &_manager->pools[(i + pool_offset)%NUM_POOLS];
 408                 shrink_pages = ttm_page_pool_free(pool, nr_free);
 409                 freed += nr_free - shrink_pages;
 410         }
 411         return freed;
 412 }
 413
 414
 415 static unsigned long
 416 ttm_pool_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
 417 {
 418         unsigned i;
 419         unsigned long count = 0;
 420
 421         for (i = 0; i < NUM_POOLS; ++i)
 422                 count += _manager->pools[i].npages;
 423
 424         return count;
 425 }
 426
 427 static void ttm_pool_mm_shrink_init(struct ttm_pool_manager *manager)
 428 {
 429         manager->mm_shrink.count_objects = ttm_pool_shrink_count;
 430         manager->mm_shrink.scan_objects = ttm_pool_shrink_scan;
 431         manager->mm_shrink.seeks = 1;
 432         register_shrinker(&manager->mm_shrink);
 433 }
 434
 435 static void ttm_pool_mm_shrink_fini(struct ttm_pool_manager *manager)
 436 {
 437         unregister_shrinker(&manager->mm_shrink);
 438 }
 439
 440 static int ttm_set_pages_caching(struct page **pages,
 441                 enum ttm_caching_state cstate, unsigned cpages)
 442 {
 443         int r = 0;
 444         /* Set page caching */
 445         switch (cstate) {
 446         case tt_uncached:
 447                 r = set_pages_array_uc(pages, cpages);
 448                 if (r)
 449                         pr_err("Failed to set %d pages to uc!\n", cpages);
 450                 break;
 451         case tt_wc:
 452                 r = set_pages_array_wc(pages, cpages);
 453                 if (r)
 454                         pr_err("Failed to set %d pages to wc!\n", cpages);
 455                 break;
 456         default:
 457                 break;
 458         }
 459         return r;
 460 }
 461
 462 /**
 463  * Free pages the pages that failed to change the caching state. If there is
 464  * any pages that have changed their caching state already put them to the
 465  * pool.
 466  */
 467 static void ttm_handle_caching_state_failure(struct list_head *pages,
 468                 int ttm_flags, enum ttm_caching_state cstate,
 469                 struct page **failed_pages, unsigned cpages)
 470 {
 471         unsigned i;
 472         /* Failed pages have to be freed */
 473         for (i = 0; i < cpages; ++i) {
 474                 list_del(&failed_pages[i]->lru);
 475                 __free_page(failed_pages[i]);
 476         }
 477 }
 478
 479 /**
 480  * Allocate new pages with correct caching.
 481  *
 482  * This function is reentrant if caller updates count depending on number of
 483  * pages returned in pages array.
 484  */
 485 static int ttm_alloc_new_pages(struct list_head *pages, gfp_t gfp_flags,
 486                 int ttm_flags, enum ttm_caching_state cstate, unsigned count)
 487 {
 488         struct page **caching_array;
 489         struct page *p;
 490         int r = 0;
 491         unsigned i, cpages;
 492         unsigned max_cpages = min(count,
 493                         (unsigned)(PAGE_SIZE/sizeof(struct page *)));
 494
 495         /* allocate array for page caching change */
 496         caching_array = kmalloc(max_cpages*sizeof(struct page *), GFP_KERNEL);
 497
 498         if (!caching_array) {
 499                 pr_err("Unable to allocate table for new pages\n");
 500                 return -ENOMEM;
 501         }
 502
 503         for (i = 0, cpages = 0; i < count; ++i) {
 504                 p = alloc_page(gfp_flags);
 505
 506                 if (!p) {
 507                         pr_err("Unable to get page %u\n", i);
 508
 509                         /* store already allocated pages in the pool after
 510                          * setting the caching state */
 511                         if (cpages) {
 512                                 r = ttm_set_pages_caching(caching_array,
 513                                                           cstate, cpages);
 514                                 if (r)
 515                                         ttm_handle_caching_state_failure(pages,
 516                                                 ttm_flags, cstate,
 517                                                 caching_array, cpages);
 518                         }
 519                         r = -ENOMEM;
 520                         goto out;
 521                 }
 522
 523 #ifdef CONFIG_HIGHMEM
 524                 /* gfp flags of highmem page should never be dma32 so we
 525                  * we should be fine in such case
 526                  */
 527                 if (!PageHighMem(p))
 528 #endif
 529                 {
 530                         caching_array[cpages++] = p;
 531                         if (cpages == max_cpages) {
 532
 533                                 r = ttm_set_pages_caching(caching_array,
 534                                                 cstate, cpages);
 535                                 if (r) {
 536                                         ttm_handle_caching_state_failure(pages,
 537                                                 ttm_flags, cstate,
 538                                                 caching_array, cpages);
 539                                         goto out;
 540                                 }
 541                                 cpages = 0;
 542                         }
 543                 }
 544
 545                 list_add(&p->lru, pages);
 546         }
 547
 548         if (cpages) {
 549                 r = ttm_set_pages_caching(caching_array, cstate, cpages);
 550                 if (r)
 551                         ttm_handle_caching_state_failure(pages,
 552                                         ttm_flags, cstate,
 553                                         caching_array, cpages);
 554         }
 555 out:
 556         kfree(caching_array);
 557
 558         return r;
 559 }
 560
 561 /**
 562  * Fill the given pool if there aren't enough pages and the requested number of
 563  * pages is small.
 564  */
 565 static void ttm_page_pool_fill_locked(struct ttm_page_pool *pool,
 566                 int ttm_flags, enum ttm_caching_state cstate, unsigned count,
 567                 unsigned long *irq_flags)
 568 {
 569         struct page *p;
 570         int r;
 571         unsigned cpages = 0;
 572         /**
 573          * Only allow one pool fill operation at a time.
 574          * If pool doesn't have enough pages for the allocation new pages are
 575          * allocated from outside of pool.
 576          */
 577         if (pool->fill_lock)
 578                 return;
 579
 580         pool->fill_lock = true;
 581
 582         /* If allocation request is small and there are not enough
 583          * pages in a pool we fill the pool up first. */
 584         if (count < _manager->options.small
 585                 && count > pool->npages) {
 586                 struct list_head new_pages;
 587                 unsigned alloc_size = _manager->options.alloc_size;
 588
 589                 /**
 590                  * Can't change page caching if in irqsave context. We have to
 591                  * drop the pool->lock.
 592                  */
 593                 spin_unlock_irqrestore(&pool->lock, *irq_flags);
 594
 595                 INIT_LIST_HEAD(&new_pages);
 596                 r = ttm_alloc_new_pages(&new_pages, pool->gfp_flags, ttm_flags,
 597                                 cstate, alloc_size);
 598                 spin_lock_irqsave(&pool->lock, *irq_flags);
 599
 600                 if (!r) {
 601                         list_splice(&new_pages, &pool->list);
 602                         ++pool->nrefills;
 603                         pool->npages += alloc_size;
 604                 } else {
 605                         pr_err("Failed to fill pool (%p)\n", pool);
 606                         /* If we have any pages left put them to the pool. */
 607                         list_for_each_entry(p, &pool->list, lru) {
 608                                 ++cpages;
 609                         }
 610                         list_splice(&new_pages, &pool->list);
 611                         pool->npages += cpages;
 612                 }
 613
 614         }
 615         pool->fill_lock = false;
 616 }
 617
 618 /**
 619  * Cut 'count' number of pages from the pool and put them on the return list.
 620  *
 621  * @return count of pages still required to fulfill the request.
 622  */
 623 static unsigned ttm_page_pool_get_pages(struct ttm_page_pool *pool,
 624                                         struct list_head *pages,
 625                                         int ttm_flags,
 626                                         enum ttm_caching_state cstate,
 627                                         unsigned count)
 628 {
 629         unsigned long irq_flags;
 630         struct list_head *p;
 631         unsigned i;
 632
 633         spin_lock_irqsave(&pool->lock, irq_flags);
 634         ttm_page_pool_fill_locked(pool, ttm_flags, cstate, count, &irq_flags);
 635
 636         if (count >= pool->npages) {
 637                 /* take all pages from the pool */
 638                 list_splice_init(&pool->list, pages);
 639                 count -= pool->npages;
 640                 pool->npages = 0;
 641                 goto out;
 642         }
 643         /* find the last pages to include for requested number of pages. Split
 644          * pool to begin and halve it to reduce search space. */
 645         if (count <= pool->npages/2) {
 646                 i = 0;
 647                 list_for_each(p, &pool->list) {
 648                         if (++i == count)
 649                                 break;
 650                 }
 651         } else {
 652                 i = pool->npages + 1;
 653                 list_for_each_prev(p, &pool->list) {
 654                         if (--i == count)
 655                                 break;
 656                 }
 657         }
 658         /* Cut 'count' number of pages from the pool */
 659         list_cut_position(pages, &pool->list, p);
 660         pool->npages -= count;
 661         count = 0;
 662 out:
 663         spin_unlock_irqrestore(&pool->lock, irq_flags);
 664         return count;
 665 }
 666
 667 /* Put all pages in pages list to correct pool to wait for reuse */
 668 static void ttm_put_pages(struct page **pages, unsigned npages, int flags,
 669                           enum ttm_caching_state cstate)
 670 {
 671         unsigned long irq_flags;
 672         struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
 673         unsigned i;
 674
 675         if (pool == NULL) {
 676                 /* No pool for this memory type so free the pages */
 677                 for (i = 0; i < npages; i++) {
 678                         if (pages[i]) {
 679                                 if (page_count(pages[i]) != 1)
 680                                         pr_err("Erroneous page count. Leaking pages.\n");
 681                                 __free_page(pages[i]);
 682                                 pages[i] = NULL;
 683                         }
 684                 }
 685                 return;
 686         }
 687
 688         spin_lock_irqsave(&pool->lock, irq_flags);
 689         for (i = 0; i < npages; i++) {
 690                 if (pages[i]) {
 691                         if (page_count(pages[i]) != 1)
 692                                 pr_err("Erroneous page count. Leaking pages.\n");
 693                         list_add_tail(&pages[i]->lru, &pool->list);
 694                         pages[i] = NULL;
 695                         pool->npages++;
 696                 }
 697         }
 698         /* Check that we don't go over the pool limit */
 699         npages = 0;
 700         if (pool->npages > _manager->options.max_size) {
 701                 npages = pool->npages - _manager->options.max_size;
 702                 /* free at least NUM_PAGES_TO_ALLOC number of pages
 703                  * to reduce calls to set_memory_wb */
 704                 if (npages < NUM_PAGES_TO_ALLOC)
 705                         npages = NUM_PAGES_TO_ALLOC;
 706         }
 707         spin_unlock_irqrestore(&pool->lock, irq_flags);
 708         if (npages)
 709                 ttm_page_pool_free(pool, npages);
 710 }
 711
 712 /*
 713  * On success pages list will hold count number of correctly
 714  * cached pages.
 715  */
 716 static int ttm_get_pages(struct page **pages, unsigned npages, int flags,
 717                          enum ttm_caching_state cstate)
 718 {
 719         struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
 720         struct list_head plist;
 721         struct page *p = NULL;
 722         gfp_t gfp_flags = GFP_USER;
 723         unsigned count;
 724         int r;
 725
 726         /* set zero flag for page allocation if required */
 727         if (flags & TTM_PAGE_FLAG_ZERO_ALLOC)
 728                 gfp_flags |= __GFP_ZERO;
 729
 730         /* No pool for cached pages */
 731         if (pool == NULL) {
 732                 if (flags & TTM_PAGE_FLAG_DMA32)
 733                         gfp_flags |= GFP_DMA32;
 734                 else
 735                         gfp_flags |= GFP_HIGHUSER;
 736
 737                 for (r = 0; r < npages; ++r) {
 738                         p = alloc_page(gfp_flags);
 739                         if (!p) {
 740
 741                                 pr_err("Unable to allocate page\n");
 742                                 return -ENOMEM;
 743                         }
 744
 745                         pages[r] = p;
 746                 }
 747                 return 0;
 748         }
 749
 750         /* combine zero flag to pool flags */
 751         gfp_flags |= pool->gfp_flags;
 752
 753         /* First we take pages from the pool */
 754         INIT_LIST_HEAD(&plist);
 755         npages = ttm_page_pool_get_pages(pool, &plist, flags, cstate, npages);
 756         count = 0;
 757         list_for_each_entry(p, &plist, lru) {
 758                 pages[count++] = p;
 759         }
 760
 761         /* clear the pages coming from the pool if requested */
 762         if (flags & TTM_PAGE_FLAG_ZERO_ALLOC) {
 763                 list_for_each_entry(p, &plist, lru) {
 764                         if (PageHighMem(p))
 765                                 clear_highpage(p);
 766                         else
 767                                 clear_page(page_address(p));
 768                 }
 769         }
 770
 771         /* If pool didn't have enough pages allocate new one. */
 772         if (npages > 0) {
 773                 /* ttm_alloc_new_pages doesn't reference pool so we can run
 774                  * multiple requests in parallel.
 775                  **/
 776                 INIT_LIST_HEAD(&plist);
 777                 r = ttm_alloc_new_pages(&plist, gfp_flags, flags, cstate, npages);
 778                 list_for_each_entry(p, &plist, lru) {
 779                         pages[count++] = p;
 780                 }
 781                 if (r) {
 782                         /* If there is any pages in the list put them back to
 783                          * the pool. */
 784                         pr_err("Failed to allocate extra pages for large request\n");
 785                         ttm_put_pages(pages, count, flags, cstate);
 786                         return r;
 787                 }
 788         }
 789
 790         return 0;
 791 }
 792
 793 static void ttm_page_pool_init_locked(struct ttm_page_pool *pool, gfp_t flags,
 794                 char *name)
 795 {
 796         spin_lock_init(&pool->lock);
 797         pool->fill_lock = false;
 798         INIT_LIST_HEAD(&pool->list);
 799         pool->npages = pool->nfrees = 0;
 800         pool->gfp_flags = flags;
 801         pool->name = name;
 802 }
 803
 804 int ttm_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)
 805 {
 806         int ret;
 807
 808         WARN_ON(_manager);
 809
 810         pr_info("Initializing pool allocator\n");
 811
 812         _manager = kzalloc(sizeof(*_manager), GFP_KERNEL);
 813
 814         ttm_page_pool_init_locked(&_manager->wc_pool, GFP_HIGHUSER, "wc");
 815
 816         ttm_page_pool_init_locked(&_manager->uc_pool, GFP_HIGHUSER, "uc");
 817
 818         ttm_page_pool_init_locked(&_manager->wc_pool_dma32,
 819                                   GFP_USER | GFP_DMA32, "wc dma");
 820
 821         ttm_page_pool_init_locked(&_manager->uc_pool_dma32,
 822                                   GFP_USER | GFP_DMA32, "uc dma");
 823
 824         _manager->options.max_size = max_pages;
 825         _manager->options.small = SMALL_ALLOCATION;
 826         _manager->options.alloc_size = NUM_PAGES_TO_ALLOC;
 827
 828         ret = kobject_init_and_add(&_manager->kobj, &ttm_pool_kobj_type,
 829                                    &glob->kobj, "pool");
 830         if (unlikely(ret != 0)) {
 831                 kobject_put(&_manager->kobj);
 832                 _manager = NULL;
 833                 return ret;
 834         }
 835
 836         ttm_pool_mm_shrink_init(_manager);
 837
 838         return 0;
 839 }
 840
 841 void ttm_page_alloc_fini(void)
 842 {
 843         int i;
 844
 845         pr_info("Finalizing pool allocator\n");
 846         ttm_pool_mm_shrink_fini(_manager);
 847
 848         for (i = 0; i < NUM_POOLS; ++i)
 849                 ttm_page_pool_free(&_manager->pools[i], FREE_ALL_PAGES);
 850
 851         kobject_put(&_manager->kobj);
 852         _manager = NULL;
 853 }
 854
 855 int ttm_pool_populate(struct ttm_tt *ttm)
 856 {
 857         struct ttm_mem_global *mem_glob = ttm->glob->mem_glob;
 858         unsigned i;
 859         int ret;
 860
 861         if (ttm->state != tt_unpopulated)
 862                 return 0;
 863
 864         for (i = 0; i < ttm->num_pages; ++i) {
 865                 ret = ttm_get_pages(&ttm->pages[i], 1,
 866                                     ttm->page_flags,
 867                                     ttm->caching_state);
 868                 if (ret != 0) {
 869                         ttm_pool_unpopulate(ttm);
 870                         return -ENOMEM;
 871                 }
 872
 873                 ret = ttm_mem_global_alloc_page(mem_glob, ttm->pages[i],
 874                                                 false, false);
 875                 if (unlikely(ret != 0)) {
 876                         ttm_pool_unpopulate(ttm);
 877                         return -ENOMEM;
 878                 }
 879         }
 880
 881         if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
 882                 ret = ttm_tt_swapin(ttm);
 883                 if (unlikely(ret != 0)) {
 884                         ttm_pool_unpopulate(ttm);
 885                         return ret;
 886                 }
 887         }
 888
 889         ttm->state = tt_unbound;
 890         return 0;
 891 }
 892 EXPORT_SYMBOL(ttm_pool_populate);
 893
 894 void ttm_pool_unpopulate(struct ttm_tt *ttm)
 895 {
 896         unsigned i;
 897
 898         for (i = 0; i < ttm->num_pages; ++i) {
 899                 if (ttm->pages[i]) {
 900                         ttm_mem_global_free_page(ttm->glob->mem_glob,
 901                                                  ttm->pages[i]);
 902                         ttm_put_pages(&ttm->pages[i], 1,
 903                                       ttm->page_flags,
 904                                       ttm->caching_state);
 905                 }
 906         }
 907         ttm->state = tt_unpopulated;
 908 }
 909 EXPORT_SYMBOL(ttm_pool_unpopulate);
 910
 911 int ttm_page_alloc_debugfs(struct seq_file *m, void *data)
 912 {
 913         struct ttm_page_pool *p;
 914         unsigned i;
 915         char *h[] = {"pool", "refills", "pages freed", "size"};
 916         if (!_manager) {
 917                 seq_printf(m, "No pool allocator running.\n");
 918                 return 0;
 919         }
 920         seq_printf(m, "%6s %12s %13s %8s\n",
 921                         h[0], h[1], h[2], h[3]);
 922         for (i = 0; i < NUM_POOLS; ++i) {
 923                 p = &_manager->pools[i];
 924
 925                 seq_printf(m, "%6s %12ld %13ld %8d\n",
 926                                 p->name, p->nrefills,
 927                                 p->nfrees, p->npages);
 928         }
 929         return 0;
 930 }
 931 EXPORT_SYMBOL(ttm_page_alloc_debugfs);