1 // SPDX-License-Identifier: GPL-2.0 OR MIT
3 * Copyright 2020 Advanced Micro Devices, Inc.
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:
12 * The above copyright notice and this permission notice shall be included in
13 * all copies or substantial portions of the Software.
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.
23 * Authors: Christian König
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.
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.
34 #include <linux/module.h>
35 #include <linux/dma-mapping.h>
36 #include <linux/debugfs.h>
37 #include <linux/highmem.h>
38 #include <linux/sched/mm.h>
41 #include <asm/set_memory.h>
44 #include <drm/ttm/ttm_pool.h>
45 #include <drm/ttm/ttm_tt.h>
46 #include <drm/ttm/ttm_bo.h>
48 #include "ttm_module.h"
51 * struct ttm_pool_dma - Helper object for coherent DMA mappings
53 * @addr: original DMA address returned for the mapping
54 * @vaddr: original vaddr return for the mapping and order in the lower bits
61 static unsigned long page_pool_size;
63 MODULE_PARM_DESC(page_pool_size, "Number of pages in the WC/UC/DMA pool");
64 module_param(page_pool_size, ulong, 0644);
66 static atomic_long_t allocated_pages;
68 static struct ttm_pool_type global_write_combined[MAX_ORDER + 1];
69 static struct ttm_pool_type global_uncached[MAX_ORDER + 1];
71 static struct ttm_pool_type global_dma32_write_combined[MAX_ORDER + 1];
72 static struct ttm_pool_type global_dma32_uncached[MAX_ORDER + 1];
74 static spinlock_t shrinker_lock;
75 static struct list_head shrinker_list;
76 static struct shrinker mm_shrinker;
78 /* Allocate pages of size 1 << order with the given gfp_flags */
79 static struct page *ttm_pool_alloc_page(struct ttm_pool *pool, gfp_t gfp_flags,
82 unsigned long attr = DMA_ATTR_FORCE_CONTIGUOUS;
83 struct ttm_pool_dma *dma;
87 /* Don't set the __GFP_COMP flag for higher order allocations.
88 * Mapping pages directly into an userspace process and calling
89 * put_page() on a TTM allocated page is illegal.
92 gfp_flags |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN |
95 if (!pool->use_dma_alloc) {
96 p = alloc_pages_node(pool->nid, gfp_flags, order);
102 dma = kmalloc(sizeof(*dma), GFP_KERNEL);
107 attr |= DMA_ATTR_NO_WARN;
109 vaddr = dma_alloc_attrs(pool->dev, (1ULL << order) * PAGE_SIZE,
110 &dma->addr, gfp_flags, attr);
114 /* TODO: This is an illegal abuse of the DMA API, but we need to rework
115 * TTM page fault handling and extend the DMA API to clean this up.
117 if (is_vmalloc_addr(vaddr))
118 p = vmalloc_to_page(vaddr);
120 p = virt_to_page(vaddr);
122 dma->vaddr = (unsigned long)vaddr | order;
123 p->private = (unsigned long)dma;
131 /* Reset the caching and pages of size 1 << order */
132 static void ttm_pool_free_page(struct ttm_pool *pool, enum ttm_caching caching,
133 unsigned int order, struct page *p)
135 unsigned long attr = DMA_ATTR_FORCE_CONTIGUOUS;
136 struct ttm_pool_dma *dma;
140 /* We don't care that set_pages_wb is inefficient here. This is only
141 * used when we have to shrink and CPU overhead is irrelevant then.
143 if (caching != ttm_cached && !PageHighMem(p))
144 set_pages_wb(p, 1 << order);
147 if (!pool || !pool->use_dma_alloc) {
148 __free_pages(p, order);
153 attr |= DMA_ATTR_NO_WARN;
155 dma = (void *)p->private;
156 vaddr = (void *)(dma->vaddr & PAGE_MASK);
157 dma_free_attrs(pool->dev, (1UL << order) * PAGE_SIZE, vaddr, dma->addr,
162 /* Apply a new caching to an array of pages */
163 static int ttm_pool_apply_caching(struct page **first, struct page **last,
164 enum ttm_caching caching)
167 unsigned int num_pages = last - first;
175 case ttm_write_combined:
176 return set_pages_array_wc(first, num_pages);
178 return set_pages_array_uc(first, num_pages);
184 /* Map pages of 1 << order size and fill the DMA address array */
185 static int ttm_pool_map(struct ttm_pool *pool, unsigned int order,
186 struct page *p, dma_addr_t **dma_addr)
191 if (pool->use_dma_alloc) {
192 struct ttm_pool_dma *dma = (void *)p->private;
196 size_t size = (1ULL << order) * PAGE_SIZE;
198 addr = dma_map_page(pool->dev, p, 0, size, DMA_BIDIRECTIONAL);
199 if (dma_mapping_error(pool->dev, addr))
203 for (i = 1 << order; i ; --i) {
204 *(*dma_addr)++ = addr;
211 /* Unmap pages of 1 << order size */
212 static void ttm_pool_unmap(struct ttm_pool *pool, dma_addr_t dma_addr,
213 unsigned int num_pages)
215 /* Unmapped while freeing the page */
216 if (pool->use_dma_alloc)
219 dma_unmap_page(pool->dev, dma_addr, (long)num_pages << PAGE_SHIFT,
223 /* Give pages into a specific pool_type */
224 static void ttm_pool_type_give(struct ttm_pool_type *pt, struct page *p)
226 unsigned int i, num_pages = 1 << pt->order;
228 for (i = 0; i < num_pages; ++i) {
230 clear_highpage(p + i);
232 clear_page(page_address(p + i));
235 spin_lock(&pt->lock);
236 list_add(&p->lru, &pt->pages);
237 spin_unlock(&pt->lock);
238 atomic_long_add(1 << pt->order, &allocated_pages);
241 /* Take pages from a specific pool_type, return NULL when nothing available */
242 static struct page *ttm_pool_type_take(struct ttm_pool_type *pt)
246 spin_lock(&pt->lock);
247 p = list_first_entry_or_null(&pt->pages, typeof(*p), lru);
249 atomic_long_sub(1 << pt->order, &allocated_pages);
252 spin_unlock(&pt->lock);
257 /* Initialize and add a pool type to the global shrinker list */
258 static void ttm_pool_type_init(struct ttm_pool_type *pt, struct ttm_pool *pool,
259 enum ttm_caching caching, unsigned int order)
262 pt->caching = caching;
264 spin_lock_init(&pt->lock);
265 INIT_LIST_HEAD(&pt->pages);
267 spin_lock(&shrinker_lock);
268 list_add_tail(&pt->shrinker_list, &shrinker_list);
269 spin_unlock(&shrinker_lock);
272 /* Remove a pool_type from the global shrinker list and free all pages */
273 static void ttm_pool_type_fini(struct ttm_pool_type *pt)
277 spin_lock(&shrinker_lock);
278 list_del(&pt->shrinker_list);
279 spin_unlock(&shrinker_lock);
281 while ((p = ttm_pool_type_take(pt)))
282 ttm_pool_free_page(pt->pool, pt->caching, pt->order, p);
285 /* Return the pool_type to use for the given caching and order */
286 static struct ttm_pool_type *ttm_pool_select_type(struct ttm_pool *pool,
287 enum ttm_caching caching,
290 if (pool->use_dma_alloc || pool->nid != NUMA_NO_NODE)
291 return &pool->caching[caching].orders[order];
295 case ttm_write_combined:
297 return &global_dma32_write_combined[order];
299 return &global_write_combined[order];
302 return &global_dma32_uncached[order];
304 return &global_uncached[order];
313 /* Free pages using the global shrinker list */
314 static unsigned int ttm_pool_shrink(void)
316 struct ttm_pool_type *pt;
317 unsigned int num_pages;
320 spin_lock(&shrinker_lock);
321 pt = list_first_entry(&shrinker_list, typeof(*pt), shrinker_list);
322 list_move_tail(&pt->shrinker_list, &shrinker_list);
323 spin_unlock(&shrinker_lock);
325 p = ttm_pool_type_take(pt);
327 ttm_pool_free_page(pt->pool, pt->caching, pt->order, p);
328 num_pages = 1 << pt->order;
336 /* Return the allocation order based for a page */
337 static unsigned int ttm_pool_page_order(struct ttm_pool *pool, struct page *p)
339 if (pool->use_dma_alloc) {
340 struct ttm_pool_dma *dma = (void *)p->private;
342 return dma->vaddr & ~PAGE_MASK;
348 /* Called when we got a page, either from a pool or newly allocated */
349 static int ttm_pool_page_allocated(struct ttm_pool *pool, unsigned int order,
350 struct page *p, dma_addr_t **dma_addr,
351 unsigned long *num_pages,
352 struct page ***pages)
358 r = ttm_pool_map(pool, order, p, dma_addr);
363 *num_pages -= 1 << order;
364 for (i = 1 << order; i; --i, ++(*pages), ++p)
371 * ttm_pool_free_range() - Free a range of TTM pages
372 * @pool: The pool used for allocating.
373 * @tt: The struct ttm_tt holding the page pointers.
374 * @caching: The page caching mode used by the range.
375 * @start_page: index for first page to free.
376 * @end_page: index for last page to free + 1.
378 * During allocation the ttm_tt page-vector may be populated with ranges of
379 * pages with different attributes if allocation hit an error without being
380 * able to completely fulfill the allocation. This function can be used
381 * to free these individual ranges.
383 static void ttm_pool_free_range(struct ttm_pool *pool, struct ttm_tt *tt,
384 enum ttm_caching caching,
385 pgoff_t start_page, pgoff_t end_page)
387 struct page **pages = tt->pages;
391 for (i = start_page; i < end_page; i += nr, pages += nr) {
392 struct ttm_pool_type *pt = NULL;
394 order = ttm_pool_page_order(pool, *pages);
397 ttm_pool_unmap(pool, tt->dma_address[i], nr);
399 pt = ttm_pool_select_type(pool, caching, order);
401 ttm_pool_type_give(pt, *pages);
403 ttm_pool_free_page(pool, caching, order, *pages);
408 * ttm_pool_alloc - Fill a ttm_tt object
410 * @pool: ttm_pool to use
411 * @tt: ttm_tt object to fill
412 * @ctx: operation context
414 * Fill the ttm_tt object with pages and also make sure to DMA map them when
417 * Returns: 0 on successe, negative error code otherwise.
419 int ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt,
420 struct ttm_operation_ctx *ctx)
422 pgoff_t num_pages = tt->num_pages;
423 dma_addr_t *dma_addr = tt->dma_address;
424 struct page **caching = tt->pages;
425 struct page **pages = tt->pages;
426 enum ttm_caching page_caching;
427 gfp_t gfp_flags = GFP_USER;
428 pgoff_t caching_divide;
433 WARN_ON(!num_pages || ttm_tt_is_populated(tt));
434 WARN_ON(dma_addr && !pool->dev);
436 if (tt->page_flags & TTM_TT_FLAG_ZERO_ALLOC)
437 gfp_flags |= __GFP_ZERO;
439 if (ctx->gfp_retry_mayfail)
440 gfp_flags |= __GFP_RETRY_MAYFAIL;
443 gfp_flags |= GFP_DMA32;
445 gfp_flags |= GFP_HIGHUSER;
447 for (order = min_t(unsigned int, MAX_ORDER, __fls(num_pages));
449 order = min_t(unsigned int, order, __fls(num_pages))) {
450 struct ttm_pool_type *pt;
452 page_caching = tt->caching;
453 pt = ttm_pool_select_type(pool, tt->caching, order);
454 p = pt ? ttm_pool_type_take(pt) : NULL;
456 r = ttm_pool_apply_caching(caching, pages,
459 goto error_free_page;
463 r = ttm_pool_page_allocated(pool, order, p,
468 goto error_free_page;
471 if (num_pages < (1 << order))
474 p = ttm_pool_type_take(pt);
478 page_caching = ttm_cached;
479 while (num_pages >= (1 << order) &&
480 (p = ttm_pool_alloc_page(pool, gfp_flags, order))) {
482 if (PageHighMem(p)) {
483 r = ttm_pool_apply_caching(caching, pages,
486 goto error_free_page;
489 r = ttm_pool_page_allocated(pool, order, p, &dma_addr,
492 goto error_free_page;
507 r = ttm_pool_apply_caching(caching, pages, tt->caching);
514 ttm_pool_free_page(pool, page_caching, order, p);
517 num_pages = tt->num_pages - num_pages;
518 caching_divide = caching - tt->pages;
519 ttm_pool_free_range(pool, tt, tt->caching, 0, caching_divide);
520 ttm_pool_free_range(pool, tt, ttm_cached, caching_divide, num_pages);
524 EXPORT_SYMBOL(ttm_pool_alloc);
527 * ttm_pool_free - Free the backing pages from a ttm_tt object
529 * @pool: Pool to give pages back to.
530 * @tt: ttm_tt object to unpopulate
532 * Give the packing pages back to a pool or free them
534 void ttm_pool_free(struct ttm_pool *pool, struct ttm_tt *tt)
536 ttm_pool_free_range(pool, tt, tt->caching, 0, tt->num_pages);
538 while (atomic_long_read(&allocated_pages) > page_pool_size)
541 EXPORT_SYMBOL(ttm_pool_free);
544 * ttm_pool_init - Initialize a pool
546 * @pool: the pool to initialize
547 * @dev: device for DMA allocations and mappings
548 * @nid: NUMA node to use for allocations
549 * @use_dma_alloc: true if coherent DMA alloc should be used
550 * @use_dma32: true if GFP_DMA32 should be used
552 * Initialize the pool and its pool types.
554 void ttm_pool_init(struct ttm_pool *pool, struct device *dev,
555 int nid, bool use_dma_alloc, bool use_dma32)
559 WARN_ON(!dev && use_dma_alloc);
563 pool->use_dma_alloc = use_dma_alloc;
564 pool->use_dma32 = use_dma32;
566 if (use_dma_alloc || nid != NUMA_NO_NODE) {
567 for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i)
568 for (j = 0; j <= MAX_ORDER; ++j)
569 ttm_pool_type_init(&pool->caching[i].orders[j],
573 EXPORT_SYMBOL(ttm_pool_init);
576 * ttm_pool_fini - Cleanup a pool
578 * @pool: the pool to clean up
580 * Free all pages in the pool and unregister the types from the global
583 void ttm_pool_fini(struct ttm_pool *pool)
587 if (pool->use_dma_alloc || pool->nid != NUMA_NO_NODE) {
588 for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i)
589 for (j = 0; j <= MAX_ORDER; ++j)
590 ttm_pool_type_fini(&pool->caching[i].orders[j]);
593 /* We removed the pool types from the LRU, but we need to also make sure
594 * that no shrinker is concurrently freeing pages from the pool.
596 synchronize_shrinkers();
598 EXPORT_SYMBOL(ttm_pool_fini);
600 /* As long as pages are available make sure to release at least one */
601 static unsigned long ttm_pool_shrinker_scan(struct shrinker *shrink,
602 struct shrink_control *sc)
604 unsigned long num_freed = 0;
607 num_freed += ttm_pool_shrink();
608 while (!num_freed && atomic_long_read(&allocated_pages));
613 /* Return the number of pages available or SHRINK_EMPTY if we have none */
614 static unsigned long ttm_pool_shrinker_count(struct shrinker *shrink,
615 struct shrink_control *sc)
617 unsigned long num_pages = atomic_long_read(&allocated_pages);
619 return num_pages ? num_pages : SHRINK_EMPTY;
622 #ifdef CONFIG_DEBUG_FS
623 /* Count the number of pages available in a pool_type */
624 static unsigned int ttm_pool_type_count(struct ttm_pool_type *pt)
626 unsigned int count = 0;
629 spin_lock(&pt->lock);
630 /* Only used for debugfs, the overhead doesn't matter */
631 list_for_each_entry(p, &pt->pages, lru)
633 spin_unlock(&pt->lock);
638 /* Print a nice header for the order */
639 static void ttm_pool_debugfs_header(struct seq_file *m)
644 for (i = 0; i <= MAX_ORDER; ++i)
645 seq_printf(m, " ---%2u---", i);
649 /* Dump information about the different pool types */
650 static void ttm_pool_debugfs_orders(struct ttm_pool_type *pt,
655 for (i = 0; i <= MAX_ORDER; ++i)
656 seq_printf(m, " %8u", ttm_pool_type_count(&pt[i]));
660 /* Dump the total amount of allocated pages */
661 static void ttm_pool_debugfs_footer(struct seq_file *m)
663 seq_printf(m, "\ntotal\t: %8lu of %8lu\n",
664 atomic_long_read(&allocated_pages), page_pool_size);
667 /* Dump the information for the global pools */
668 static int ttm_pool_debugfs_globals_show(struct seq_file *m, void *data)
670 ttm_pool_debugfs_header(m);
672 spin_lock(&shrinker_lock);
673 seq_puts(m, "wc\t:");
674 ttm_pool_debugfs_orders(global_write_combined, m);
675 seq_puts(m, "uc\t:");
676 ttm_pool_debugfs_orders(global_uncached, m);
677 seq_puts(m, "wc 32\t:");
678 ttm_pool_debugfs_orders(global_dma32_write_combined, m);
679 seq_puts(m, "uc 32\t:");
680 ttm_pool_debugfs_orders(global_dma32_uncached, m);
681 spin_unlock(&shrinker_lock);
683 ttm_pool_debugfs_footer(m);
687 DEFINE_SHOW_ATTRIBUTE(ttm_pool_debugfs_globals);
690 * ttm_pool_debugfs - Debugfs dump function for a pool
692 * @pool: the pool to dump the information for
693 * @m: seq_file to dump to
695 * Make a debugfs dump with the per pool and global information.
697 int ttm_pool_debugfs(struct ttm_pool *pool, struct seq_file *m)
701 if (!pool->use_dma_alloc) {
702 seq_puts(m, "unused\n");
706 ttm_pool_debugfs_header(m);
708 spin_lock(&shrinker_lock);
709 for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i) {
715 case ttm_write_combined:
716 seq_puts(m, "wc\t:");
719 seq_puts(m, "uc\t:");
722 ttm_pool_debugfs_orders(pool->caching[i].orders, m);
724 spin_unlock(&shrinker_lock);
726 ttm_pool_debugfs_footer(m);
729 EXPORT_SYMBOL(ttm_pool_debugfs);
731 /* Test the shrinker functions and dump the result */
732 static int ttm_pool_debugfs_shrink_show(struct seq_file *m, void *data)
734 struct shrink_control sc = { .gfp_mask = GFP_NOFS };
736 fs_reclaim_acquire(GFP_KERNEL);
737 seq_printf(m, "%lu/%lu\n", ttm_pool_shrinker_count(&mm_shrinker, &sc),
738 ttm_pool_shrinker_scan(&mm_shrinker, &sc));
739 fs_reclaim_release(GFP_KERNEL);
743 DEFINE_SHOW_ATTRIBUTE(ttm_pool_debugfs_shrink);
748 * ttm_pool_mgr_init - Initialize globals
750 * @num_pages: default number of pages
752 * Initialize the global locks and lists for the MM shrinker.
754 int ttm_pool_mgr_init(unsigned long num_pages)
759 page_pool_size = num_pages;
761 spin_lock_init(&shrinker_lock);
762 INIT_LIST_HEAD(&shrinker_list);
764 for (i = 0; i <= MAX_ORDER; ++i) {
765 ttm_pool_type_init(&global_write_combined[i], NULL,
766 ttm_write_combined, i);
767 ttm_pool_type_init(&global_uncached[i], NULL, ttm_uncached, i);
769 ttm_pool_type_init(&global_dma32_write_combined[i], NULL,
770 ttm_write_combined, i);
771 ttm_pool_type_init(&global_dma32_uncached[i], NULL,
775 #ifdef CONFIG_DEBUG_FS
776 debugfs_create_file("page_pool", 0444, ttm_debugfs_root, NULL,
777 &ttm_pool_debugfs_globals_fops);
778 debugfs_create_file("page_pool_shrink", 0400, ttm_debugfs_root, NULL,
779 &ttm_pool_debugfs_shrink_fops);
782 mm_shrinker.count_objects = ttm_pool_shrinker_count;
783 mm_shrinker.scan_objects = ttm_pool_shrinker_scan;
784 mm_shrinker.seeks = 1;
785 return register_shrinker(&mm_shrinker, "drm-ttm_pool");
789 * ttm_pool_mgr_fini - Finalize globals
791 * Cleanup the global pools and unregister the MM shrinker.
793 void ttm_pool_mgr_fini(void)
797 for (i = 0; i <= MAX_ORDER; ++i) {
798 ttm_pool_type_fini(&global_write_combined[i]);
799 ttm_pool_type_fini(&global_uncached[i]);
801 ttm_pool_type_fini(&global_dma32_write_combined[i]);
802 ttm_pool_type_fini(&global_dma32_uncached[i]);
805 unregister_shrinker(&mm_shrinker);
806 WARN_ON(!list_empty(&shrinker_list));