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1// SPDX-License-Identifier: GPL-2.0 OR MIT
2/*
3 * Copyright 2020 Advanced Micro Devices, Inc.
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software"),
7 * to deal in the Software without restriction, including without limitation
8 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9 * and/or sell copies of the Software, and to permit persons to whom the
10 * Software is furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be included in
13 * all copies or substantial portions 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 NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
19 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
20 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
21 * OTHER DEALINGS IN THE SOFTWARE.
22 *
23 * Authors: Christian König
24 */
25
26/* Pooling of allocated pages is necessary because changing the caching
27 * attributes on x86 of the linear mapping requires a costly cross CPU TLB
28 * invalidate for those addresses.
29 *
30 * Additional to that allocations from the DMA coherent API are pooled as well
31 * cause they are rather slow compared to alloc_pages+map.
32 */
33
34#include <linux/module.h>
35#include <linux/dma-mapping.h>
36#include <linux/highmem.h>
37#include <linux/sched/mm.h>
38
39#ifdef CONFIG_X86
40#include <asm/set_memory.h>
41#endif
42
43#include <drm/ttm/ttm_pool.h>
44#include <drm/ttm/ttm_bo_driver.h>
45#include <drm/ttm/ttm_tt.h>
46
47#include "ttm_module.h"
48
49/**
50 * struct ttm_pool_dma - Helper object for coherent DMA mappings
51 *
52 * @addr: original DMA address returned for the mapping
53 * @vaddr: original vaddr return for the mapping and order in the lower bits
54 */
55struct ttm_pool_dma {
56 dma_addr_t addr;
57 unsigned long vaddr;
58};
59
60static unsigned long page_pool_size;
61
62MODULE_PARM_DESC(page_pool_size, "Number of pages in the WC/UC/DMA pool");
63module_param(page_pool_size, ulong, 0644);
64
65static atomic_long_t allocated_pages;
66
67static struct ttm_pool_type global_write_combined[MAX_ORDER];
68static struct ttm_pool_type global_uncached[MAX_ORDER];
69
70static struct ttm_pool_type global_dma32_write_combined[MAX_ORDER];
71static struct ttm_pool_type global_dma32_uncached[MAX_ORDER];
72
73static struct mutex shrinker_lock;
74static struct list_head shrinker_list;
75static struct shrinker mm_shrinker;
76
77/* Allocate pages of size 1 << order with the given gfp_flags */
78static struct page *ttm_pool_alloc_page(struct ttm_pool *pool, gfp_t gfp_flags,
79 unsigned int order)
80{
81 unsigned long attr = DMA_ATTR_FORCE_CONTIGUOUS;
82 struct ttm_pool_dma *dma;
83 struct page *p;
84 void *vaddr;
85
86 /* Don't set the __GFP_COMP flag for higher order allocations.
87 * Mapping pages directly into an userspace process and calling
88 * put_page() on a TTM allocated page is illegal.
89 */
90 if (order)
91 gfp_flags |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN |
92 __GFP_KSWAPD_RECLAIM;
93
94 if (!pool->use_dma_alloc) {
95 p = alloc_pages(gfp_flags, order);
96 if (p)
97 p->private = order;
98 return p;
99 }
100
101 dma = kmalloc(sizeof(*dma), GFP_KERNEL);
102 if (!dma)
103 return NULL;
104
105 if (order)
106 attr |= DMA_ATTR_NO_WARN;
107
108 vaddr = dma_alloc_attrs(pool->dev, (1ULL << order) * PAGE_SIZE,
109 &dma->addr, gfp_flags, attr);
110 if (!vaddr)
111 goto error_free;
112
113 /* TODO: This is an illegal abuse of the DMA API, but we need to rework
114 * TTM page fault handling and extend the DMA API to clean this up.
115 */
116 if (is_vmalloc_addr(vaddr))
117 p = vmalloc_to_page(vaddr);
118 else
119 p = virt_to_page(vaddr);
120
121 dma->vaddr = (unsigned long)vaddr | order;
122 p->private = (unsigned long)dma;
123 return p;
124
125error_free:
126 kfree(dma);
127 return NULL;
128}
129
130/* Reset the caching and pages of size 1 << order */
131static void ttm_pool_free_page(struct ttm_pool *pool, enum ttm_caching caching,
132 unsigned int order, struct page *p)
133{
134 unsigned long attr = DMA_ATTR_FORCE_CONTIGUOUS;
135 struct ttm_pool_dma *dma;
136 void *vaddr;
137
138#ifdef CONFIG_X86
139 /* We don't care that set_pages_wb is inefficient here. This is only
140 * used when we have to shrink and CPU overhead is irrelevant then.
141 */
142 if (caching != ttm_cached && !PageHighMem(p))
143 set_pages_wb(p, 1 << order);
144#endif
145
146 if (!pool || !pool->use_dma_alloc) {
147 __free_pages(p, order);
148 return;
149 }
150
151 if (order)
152 attr |= DMA_ATTR_NO_WARN;
153
154 dma = (void *)p->private;
155 vaddr = (void *)(dma->vaddr & PAGE_MASK);
156 dma_free_attrs(pool->dev, (1UL << order) * PAGE_SIZE, vaddr, dma->addr,
157 attr);
158 kfree(dma);
159}
160
161/* Apply a new caching to an array of pages */
162static int ttm_pool_apply_caching(struct page **first, struct page **last,
163 enum ttm_caching caching)
164{
165#ifdef CONFIG_X86
166 unsigned int num_pages = last - first;
167
168 if (!num_pages)
169 return 0;
170
171 switch (caching) {
172 case ttm_cached:
173 break;
174 case ttm_write_combined:
175 return set_pages_array_wc(first, num_pages);
176 case ttm_uncached:
177 return set_pages_array_uc(first, num_pages);
178 }
179#endif
180 return 0;
181}
182
183/* Map pages of 1 << order size and fill the DMA address array */
184static int ttm_pool_map(struct ttm_pool *pool, unsigned int order,
185 struct page *p, dma_addr_t **dma_addr)
186{
187 dma_addr_t addr;
188 unsigned int i;
189
190 if (pool->use_dma_alloc) {
191 struct ttm_pool_dma *dma = (void *)p->private;
192
193 addr = dma->addr;
194 } else {
195 size_t size = (1ULL << order) * PAGE_SIZE;
196
197 addr = dma_map_page(pool->dev, p, 0, size, DMA_BIDIRECTIONAL);
198 if (dma_mapping_error(pool->dev, addr))
199 return -EFAULT;
200 }
201
202 for (i = 1 << order; i ; --i) {
203 *(*dma_addr)++ = addr;
204 addr += PAGE_SIZE;
205 }
206
207 return 0;
208}
209
210/* Unmap pages of 1 << order size */
211static void ttm_pool_unmap(struct ttm_pool *pool, dma_addr_t dma_addr,
212 unsigned int num_pages)
213{
214 /* Unmapped while freeing the page */
215 if (pool->use_dma_alloc)
216 return;
217
218 dma_unmap_page(pool->dev, dma_addr, (long)num_pages << PAGE_SHIFT,
219 DMA_BIDIRECTIONAL);
220}
221
222/* Give pages into a specific pool_type */
223static void ttm_pool_type_give(struct ttm_pool_type *pt, struct page *p)
224{
225 unsigned int i, num_pages = 1 << pt->order;
226
227 for (i = 0; i < num_pages; ++i) {
228 if (PageHighMem(p))
229 clear_highpage(p + i);
230 else
231 clear_page(page_address(p + i));
232 }
233
234 spin_lock(&pt->lock);
235 list_add(&p->lru, &pt->pages);
236 spin_unlock(&pt->lock);
237 atomic_long_add(1 << pt->order, &allocated_pages);
238}
239
240/* Take pages from a specific pool_type, return NULL when nothing available */
241static struct page *ttm_pool_type_take(struct ttm_pool_type *pt)
242{
243 struct page *p;
244
245 spin_lock(&pt->lock);
246 p = list_first_entry_or_null(&pt->pages, typeof(*p), lru);
247 if (p) {
248 atomic_long_sub(1 << pt->order, &allocated_pages);
249 list_del(&p->lru);
250 }
251 spin_unlock(&pt->lock);
252
253 return p;
254}
255
256/* Initialize and add a pool type to the global shrinker list */
257static void ttm_pool_type_init(struct ttm_pool_type *pt, struct ttm_pool *pool,
258 enum ttm_caching caching, unsigned int order)
259{
260 pt->pool = pool;
261 pt->caching = caching;
262 pt->order = order;
263 spin_lock_init(&pt->lock);
264 INIT_LIST_HEAD(&pt->pages);
265
266 mutex_lock(&shrinker_lock);
267 list_add_tail(&pt->shrinker_list, &shrinker_list);
268 mutex_unlock(&shrinker_lock);
269}
270
271/* Remove a pool_type from the global shrinker list and free all pages */
272static void ttm_pool_type_fini(struct ttm_pool_type *pt)
273{
274 struct page *p;
275
276 mutex_lock(&shrinker_lock);
277 list_del(&pt->shrinker_list);
278 mutex_unlock(&shrinker_lock);
279
280 while ((p = ttm_pool_type_take(pt)))
281 ttm_pool_free_page(pt->pool, pt->caching, pt->order, p);
282}
283
284/* Return the pool_type to use for the given caching and order */
285static struct ttm_pool_type *ttm_pool_select_type(struct ttm_pool *pool,
286 enum ttm_caching caching,
287 unsigned int order)
288{
289 if (pool->use_dma_alloc)
290 return &pool->caching[caching].orders[order];
291
292#ifdef CONFIG_X86
293 switch (caching) {
294 case ttm_write_combined:
295 if (pool->use_dma32)
296 return &global_dma32_write_combined[order];
297
298 return &global_write_combined[order];
299 case ttm_uncached:
300 if (pool->use_dma32)
301 return &global_dma32_uncached[order];
302
303 return &global_uncached[order];
304 default:
305 break;
306 }
307#endif
308
309 return NULL;
310}
311
312/* Free pages using the global shrinker list */
313static unsigned int ttm_pool_shrink(void)
314{
315 struct ttm_pool_type *pt;
316 unsigned int num_freed;
317 struct page *p;
318
319 mutex_lock(&shrinker_lock);
320 pt = list_first_entry(&shrinker_list, typeof(*pt), shrinker_list);
321
322 p = ttm_pool_type_take(pt);
323 if (p) {
324 ttm_pool_free_page(pt->pool, pt->caching, pt->order, p);
325 num_freed = 1 << pt->order;
326 } else {
327 num_freed = 0;
328 }
329
330 list_move_tail(&pt->shrinker_list, &shrinker_list);
331 mutex_unlock(&shrinker_lock);
332
333 return num_freed;
334}
335
336/* Return the allocation order based for a page */
337static unsigned int ttm_pool_page_order(struct ttm_pool *pool, struct page *p)
338{
339 if (pool->use_dma_alloc) {
340 struct ttm_pool_dma *dma = (void *)p->private;
341
342 return dma->vaddr & ~PAGE_MASK;
343 }
344
345 return p->private;
346}
347
348/**
349 * ttm_pool_alloc - Fill a ttm_tt object
350 *
351 * @pool: ttm_pool to use
352 * @tt: ttm_tt object to fill
353 * @ctx: operation context
354 *
355 * Fill the ttm_tt object with pages and also make sure to DMA map them when
356 * necessary.
357 *
358 * Returns: 0 on successe, negative error code otherwise.
359 */
360int ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt,
361 struct ttm_operation_ctx *ctx)
362{
363 unsigned long num_pages = tt->num_pages;
364 dma_addr_t *dma_addr = tt->dma_address;
365 struct page **caching = tt->pages;
366 struct page **pages = tt->pages;
367 gfp_t gfp_flags = GFP_USER;
368 unsigned int i, order;
369 struct page *p;
370 int r;
371
372 WARN_ON(!num_pages || ttm_tt_is_populated(tt));
373 WARN_ON(dma_addr && !pool->dev);
374
375 if (tt->page_flags & TTM_PAGE_FLAG_ZERO_ALLOC)
376 gfp_flags |= __GFP_ZERO;
377
378 if (ctx->gfp_retry_mayfail)
379 gfp_flags |= __GFP_RETRY_MAYFAIL;
380
381 if (pool->use_dma32)
382 gfp_flags |= GFP_DMA32;
383 else
384 gfp_flags |= GFP_HIGHUSER;
385
386 for (order = min_t(unsigned int, MAX_ORDER - 1, __fls(num_pages));
387 num_pages;
388 order = min_t(unsigned int, order, __fls(num_pages))) {
389 bool apply_caching = false;
390 struct ttm_pool_type *pt;
391
392 pt = ttm_pool_select_type(pool, tt->caching, order);
393 p = pt ? ttm_pool_type_take(pt) : NULL;
394 if (p) {
395 apply_caching = true;
396 } else {
397 p = ttm_pool_alloc_page(pool, gfp_flags, order);
398 if (p && PageHighMem(p))
399 apply_caching = true;
400 }
401
402 if (!p) {
403 if (order) {
404 --order;
405 continue;
406 }
407 r = -ENOMEM;
408 goto error_free_all;
409 }
410
411 if (apply_caching) {
412 r = ttm_pool_apply_caching(caching, pages,
413 tt->caching);
414 if (r)
415 goto error_free_page;
416 caching = pages + (1 << order);
417 }
418
419 if (dma_addr) {
420 r = ttm_pool_map(pool, order, p, &dma_addr);
421 if (r)
422 goto error_free_page;
423 }
424
425 num_pages -= 1 << order;
426 for (i = 1 << order; i; --i)
427 *(pages++) = p++;
428 }
429
430 r = ttm_pool_apply_caching(caching, pages, tt->caching);
431 if (r)
432 goto error_free_all;
433
434 return 0;
435
436error_free_page:
437 ttm_pool_free_page(pool, tt->caching, order, p);
438
439error_free_all:
440 num_pages = tt->num_pages - num_pages;
441 for (i = 0; i < num_pages; ) {
442 order = ttm_pool_page_order(pool, tt->pages[i]);
443 ttm_pool_free_page(pool, tt->caching, order, tt->pages[i]);
444 i += 1 << order;
445 }
446
447 return r;
448}
449EXPORT_SYMBOL(ttm_pool_alloc);
450
451/**
452 * ttm_pool_free - Free the backing pages from a ttm_tt object
453 *
454 * @pool: Pool to give pages back to.
455 * @tt: ttm_tt object to unpopulate
456 *
457 * Give the packing pages back to a pool or free them
458 */
459void ttm_pool_free(struct ttm_pool *pool, struct ttm_tt *tt)
460{
461 unsigned int i;
462
463 for (i = 0; i < tt->num_pages; ) {
464 struct page *p = tt->pages[i];
465 unsigned int order, num_pages;
466 struct ttm_pool_type *pt;
467
468 order = ttm_pool_page_order(pool, p);
469 num_pages = 1ULL << order;
470 if (tt->dma_address)
471 ttm_pool_unmap(pool, tt->dma_address[i], num_pages);
472
473 pt = ttm_pool_select_type(pool, tt->caching, order);
474 if (pt)
475 ttm_pool_type_give(pt, tt->pages[i]);
476 else
477 ttm_pool_free_page(pool, tt->caching, order,
478 tt->pages[i]);
479
480 i += num_pages;
481 }
482
483 while (atomic_long_read(&allocated_pages) > page_pool_size)
484 ttm_pool_shrink();
485}
486EXPORT_SYMBOL(ttm_pool_free);
487
488/**
489 * ttm_pool_init - Initialize a pool
490 *
491 * @pool: the pool to initialize
492 * @dev: device for DMA allocations and mappings
493 * @use_dma_alloc: true if coherent DMA alloc should be used
494 * @use_dma32: true if GFP_DMA32 should be used
495 *
496 * Initialize the pool and its pool types.
497 */
498void ttm_pool_init(struct ttm_pool *pool, struct device *dev,
499 bool use_dma_alloc, bool use_dma32)
500{
501 unsigned int i, j;
502
503 WARN_ON(!dev && use_dma_alloc);
504
505 pool->dev = dev;
506 pool->use_dma_alloc = use_dma_alloc;
507 pool->use_dma32 = use_dma32;
508
509 if (use_dma_alloc) {
510 for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i)
511 for (j = 0; j < MAX_ORDER; ++j)
512 ttm_pool_type_init(&pool->caching[i].orders[j],
513 pool, i, j);
514 }
515}
516
517/**
518 * ttm_pool_fini - Cleanup a pool
519 *
520 * @pool: the pool to clean up
521 *
522 * Free all pages in the pool and unregister the types from the global
523 * shrinker.
524 */
525void ttm_pool_fini(struct ttm_pool *pool)
526{
527 unsigned int i, j;
528
529 if (pool->use_dma_alloc) {
530 for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i)
531 for (j = 0; j < MAX_ORDER; ++j)
532 ttm_pool_type_fini(&pool->caching[i].orders[j]);
533 }
534}
535
536/* As long as pages are available make sure to release at least one */
537static unsigned long ttm_pool_shrinker_scan(struct shrinker *shrink,
538 struct shrink_control *sc)
539{
540 unsigned long num_freed = 0;
541
542 do
543 num_freed += ttm_pool_shrink();
544 while (!num_freed && atomic_long_read(&allocated_pages));
545
546 return num_freed;
547}
548
549/* Return the number of pages available or SHRINK_EMPTY if we have none */
550static unsigned long ttm_pool_shrinker_count(struct shrinker *shrink,
551 struct shrink_control *sc)
552{
553 unsigned long num_pages = atomic_long_read(&allocated_pages);
554
555 return num_pages ? num_pages : SHRINK_EMPTY;
556}
557
558#ifdef CONFIG_DEBUG_FS
559/* Count the number of pages available in a pool_type */
560static unsigned int ttm_pool_type_count(struct ttm_pool_type *pt)
561{
562 unsigned int count = 0;
563 struct page *p;
564
565 spin_lock(&pt->lock);
566 /* Only used for debugfs, the overhead doesn't matter */
567 list_for_each_entry(p, &pt->pages, lru)
568 ++count;
569 spin_unlock(&pt->lock);
570
571 return count;
572}
573
574/* Print a nice header for the order */
575static void ttm_pool_debugfs_header(struct seq_file *m)
576{
577 unsigned int i;
578
579 seq_puts(m, "\t ");
580 for (i = 0; i < MAX_ORDER; ++i)
581 seq_printf(m, " ---%2u---", i);
582 seq_puts(m, "\n");
583}
584
585/* Dump information about the different pool types */
586static void ttm_pool_debugfs_orders(struct ttm_pool_type *pt,
587 struct seq_file *m)
588{
589 unsigned int i;
590
591 for (i = 0; i < MAX_ORDER; ++i)
592 seq_printf(m, " %8u", ttm_pool_type_count(&pt[i]));
593 seq_puts(m, "\n");
594}
595
596/* Dump the total amount of allocated pages */
597static void ttm_pool_debugfs_footer(struct seq_file *m)
598{
599 seq_printf(m, "\ntotal\t: %8lu of %8lu\n",
600 atomic_long_read(&allocated_pages), page_pool_size);
601}
602
603/* Dump the information for the global pools */
604static int ttm_pool_debugfs_globals_show(struct seq_file *m, void *data)
605{
606 ttm_pool_debugfs_header(m);
607
608 mutex_lock(&shrinker_lock);
609 seq_puts(m, "wc\t:");
610 ttm_pool_debugfs_orders(global_write_combined, m);
611 seq_puts(m, "uc\t:");
612 ttm_pool_debugfs_orders(global_uncached, m);
613 seq_puts(m, "wc 32\t:");
614 ttm_pool_debugfs_orders(global_dma32_write_combined, m);
615 seq_puts(m, "uc 32\t:");
616 ttm_pool_debugfs_orders(global_dma32_uncached, m);
617 mutex_unlock(&shrinker_lock);
618
619 ttm_pool_debugfs_footer(m);
620
621 return 0;
622}
623DEFINE_SHOW_ATTRIBUTE(ttm_pool_debugfs_globals);
624
625/**
626 * ttm_pool_debugfs - Debugfs dump function for a pool
627 *
628 * @pool: the pool to dump the information for
629 * @m: seq_file to dump to
630 *
631 * Make a debugfs dump with the per pool and global information.
632 */
633int ttm_pool_debugfs(struct ttm_pool *pool, struct seq_file *m)
634{
635 unsigned int i;
636
637 if (!pool->use_dma_alloc) {
638 seq_puts(m, "unused\n");
639 return 0;
640 }
641
642 ttm_pool_debugfs_header(m);
643
644 mutex_lock(&shrinker_lock);
645 for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i) {
646 seq_puts(m, "DMA ");
647 switch (i) {
648 case ttm_cached:
649 seq_puts(m, "\t:");
650 break;
651 case ttm_write_combined:
652 seq_puts(m, "wc\t:");
653 break;
654 case ttm_uncached:
655 seq_puts(m, "uc\t:");
656 break;
657 }
658 ttm_pool_debugfs_orders(pool->caching[i].orders, m);
659 }
660 mutex_unlock(&shrinker_lock);
661
662 ttm_pool_debugfs_footer(m);
663 return 0;
664}
665EXPORT_SYMBOL(ttm_pool_debugfs);
666
667/* Test the shrinker functions and dump the result */
668static int ttm_pool_debugfs_shrink_show(struct seq_file *m, void *data)
669{
670 struct shrink_control sc = { .gfp_mask = GFP_NOFS };
671
672 fs_reclaim_acquire(GFP_KERNEL);
673 seq_printf(m, "%lu/%lu\n", ttm_pool_shrinker_count(&mm_shrinker, &sc),
674 ttm_pool_shrinker_scan(&mm_shrinker, &sc));
675 fs_reclaim_release(GFP_KERNEL);
676
677 return 0;
678}
679DEFINE_SHOW_ATTRIBUTE(ttm_pool_debugfs_shrink);
680
681#endif
682
683/**
684 * ttm_pool_mgr_init - Initialize globals
685 *
686 * @num_pages: default number of pages
687 *
688 * Initialize the global locks and lists for the MM shrinker.
689 */
690int ttm_pool_mgr_init(unsigned long num_pages)
691{
692 unsigned int i;
693
694 if (!page_pool_size)
695 page_pool_size = num_pages;
696
697 mutex_init(&shrinker_lock);
698 INIT_LIST_HEAD(&shrinker_list);
699
700 for (i = 0; i < MAX_ORDER; ++i) {
701 ttm_pool_type_init(&global_write_combined[i], NULL,
702 ttm_write_combined, i);
703 ttm_pool_type_init(&global_uncached[i], NULL, ttm_uncached, i);
704
705 ttm_pool_type_init(&global_dma32_write_combined[i], NULL,
706 ttm_write_combined, i);
707 ttm_pool_type_init(&global_dma32_uncached[i], NULL,
708 ttm_uncached, i);
709 }
710
711#ifdef CONFIG_DEBUG_FS
712 debugfs_create_file("page_pool", 0444, ttm_debugfs_root, NULL,
713 &ttm_pool_debugfs_globals_fops);
714 debugfs_create_file("page_pool_shrink", 0400, ttm_debugfs_root, NULL,
715 &ttm_pool_debugfs_shrink_fops);
716#endif
717
718 mm_shrinker.count_objects = ttm_pool_shrinker_count;
719 mm_shrinker.scan_objects = ttm_pool_shrinker_scan;
720 mm_shrinker.seeks = 1;
721 return register_shrinker(&mm_shrinker);
722}
723
724/**
725 * ttm_pool_mgr_fini - Finalize globals
726 *
727 * Cleanup the global pools and unregister the MM shrinker.
728 */
729void ttm_pool_mgr_fini(void)
730{
731 unsigned int i;
732
733 for (i = 0; i < MAX_ORDER; ++i) {
734 ttm_pool_type_fini(&global_write_combined[i]);
735 ttm_pool_type_fini(&global_uncached[i]);
736
737 ttm_pool_type_fini(&global_dma32_write_combined[i]);
738 ttm_pool_type_fini(&global_dma32_uncached[i]);
739 }
740
741 unregister_shrinker(&mm_shrinker);
742 WARN_ON(!list_empty(&shrinker_list));
743}