// SPDX-License-Identifier: GPL-2.0 OR MIT /* * Copyright 2020 Advanced Micro Devices, Inc. * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR * OTHER DEALINGS IN THE SOFTWARE. * * Authors: Christian König */ /* Pooling of allocated pages is necessary because changing the caching * attributes on x86 of the linear mapping requires a costly cross CPU TLB * invalidate for those addresses. * * Additional to that allocations from the DMA coherent API are pooled as well * cause they are rather slow compared to alloc_pages+map. */ #include #include #include #include #ifdef CONFIG_X86 #include #endif #include #include #include #include "ttm_module.h" /** * struct ttm_pool_dma - Helper object for coherent DMA mappings * * @addr: original DMA address returned for the mapping * @vaddr: original vaddr return for the mapping and order in the lower bits */ struct ttm_pool_dma { dma_addr_t addr; unsigned long vaddr; }; static unsigned long page_pool_size; MODULE_PARM_DESC(page_pool_size, "Number of pages in the WC/UC/DMA pool"); module_param(page_pool_size, ulong, 0644); static atomic_long_t allocated_pages; static struct ttm_pool_type global_write_combined[MAX_ORDER]; static struct ttm_pool_type global_uncached[MAX_ORDER]; static struct ttm_pool_type global_dma32_write_combined[MAX_ORDER]; static struct ttm_pool_type global_dma32_uncached[MAX_ORDER]; static struct mutex shrinker_lock; static struct list_head shrinker_list; static struct shrinker mm_shrinker; /* Allocate pages of size 1 << order with the given gfp_flags */ static struct page *ttm_pool_alloc_page(struct ttm_pool *pool, gfp_t gfp_flags, unsigned int order) { unsigned long attr = DMA_ATTR_FORCE_CONTIGUOUS; struct ttm_pool_dma *dma; struct page *p; void *vaddr; /* Don't set the __GFP_COMP flag for higher order allocations. * Mapping pages directly into an userspace process and calling * put_page() on a TTM allocated page is illegal. */ if (order) gfp_flags |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM; if (!pool->use_dma_alloc) { p = alloc_pages(gfp_flags, order); if (p) p->private = order; return p; } dma = kmalloc(sizeof(*dma), GFP_KERNEL); if (!dma) return NULL; if (order) attr |= DMA_ATTR_NO_WARN; vaddr = dma_alloc_attrs(pool->dev, (1ULL << order) * PAGE_SIZE, &dma->addr, gfp_flags, attr); if (!vaddr) goto error_free; /* TODO: This is an illegal abuse of the DMA API, but we need to rework * TTM page fault handling and extend the DMA API to clean this up. */ if (is_vmalloc_addr(vaddr)) p = vmalloc_to_page(vaddr); else p = virt_to_page(vaddr); dma->vaddr = (unsigned long)vaddr | order; p->private = (unsigned long)dma; return p; error_free: kfree(dma); return NULL; } /* Reset the caching and pages of size 1 << order */ static void ttm_pool_free_page(struct ttm_pool *pool, enum ttm_caching caching, unsigned int order, struct page *p) { unsigned long attr = DMA_ATTR_FORCE_CONTIGUOUS; struct ttm_pool_dma *dma; void *vaddr; #ifdef CONFIG_X86 /* We don't care that set_pages_wb is inefficient here. This is only * used when we have to shrink and CPU overhead is irrelevant then. */ if (caching != ttm_cached && !PageHighMem(p)) set_pages_wb(p, 1 << order); #endif if (!pool || !pool->use_dma_alloc) { __free_pages(p, order); return; } if (order) attr |= DMA_ATTR_NO_WARN; dma = (void *)p->private; vaddr = (void *)(dma->vaddr & PAGE_MASK); dma_free_attrs(pool->dev, (1UL << order) * PAGE_SIZE, vaddr, dma->addr, attr); kfree(dma); } /* Apply a new caching to an array of pages */ static int ttm_pool_apply_caching(struct page **first, struct page **last, enum ttm_caching caching) { #ifdef CONFIG_X86 unsigned int num_pages = last - first; if (!num_pages) return 0; switch (caching) { case ttm_cached: break; case ttm_write_combined: return set_pages_array_wc(first, num_pages); case ttm_uncached: return set_pages_array_uc(first, num_pages); } #endif return 0; } /* Map pages of 1 << order size and fill the DMA address array */ static int ttm_pool_map(struct ttm_pool *pool, unsigned int order, struct page *p, dma_addr_t **dma_addr) { dma_addr_t addr; unsigned int i; if (pool->use_dma_alloc) { struct ttm_pool_dma *dma = (void *)p->private; addr = dma->addr; } else { size_t size = (1ULL << order) * PAGE_SIZE; addr = dma_map_page(pool->dev, p, 0, size, DMA_BIDIRECTIONAL); if (dma_mapping_error(pool->dev, addr)) return -EFAULT; } for (i = 1 << order; i ; --i) { *(*dma_addr)++ = addr; addr += PAGE_SIZE; } return 0; } /* Unmap pages of 1 << order size */ static void ttm_pool_unmap(struct ttm_pool *pool, dma_addr_t dma_addr, unsigned int num_pages) { /* Unmapped while freeing the page */ if (pool->use_dma_alloc) return; dma_unmap_page(pool->dev, dma_addr, (long)num_pages << PAGE_SHIFT, DMA_BIDIRECTIONAL); } /* Give pages into a specific pool_type */ static void ttm_pool_type_give(struct ttm_pool_type *pt, struct page *p) { unsigned int i, num_pages = 1 << pt->order; for (i = 0; i < num_pages; ++i) { if (PageHighMem(p)) clear_highpage(p + i); else clear_page(page_address(p + i)); } spin_lock(&pt->lock); list_add(&p->lru, &pt->pages); spin_unlock(&pt->lock); atomic_long_add(1 << pt->order, &allocated_pages); } /* Take pages from a specific pool_type, return NULL when nothing available */ static struct page *ttm_pool_type_take(struct ttm_pool_type *pt) { struct page *p; spin_lock(&pt->lock); p = list_first_entry_or_null(&pt->pages, typeof(*p), lru); if (p) { atomic_long_sub(1 << pt->order, &allocated_pages); list_del(&p->lru); } spin_unlock(&pt->lock); return p; } /* Initialize and add a pool type to the global shrinker list */ static void ttm_pool_type_init(struct ttm_pool_type *pt, struct ttm_pool *pool, enum ttm_caching caching, unsigned int order) { pt->pool = pool; pt->caching = caching; pt->order = order; spin_lock_init(&pt->lock); INIT_LIST_HEAD(&pt->pages); mutex_lock(&shrinker_lock); list_add_tail(&pt->shrinker_list, &shrinker_list); mutex_unlock(&shrinker_lock); } /* Remove a pool_type from the global shrinker list and free all pages */ static void ttm_pool_type_fini(struct ttm_pool_type *pt) { struct page *p; mutex_lock(&shrinker_lock); list_del(&pt->shrinker_list); mutex_unlock(&shrinker_lock); while ((p = ttm_pool_type_take(pt))) ttm_pool_free_page(pt->pool, pt->caching, pt->order, p); } /* Return the pool_type to use for the given caching and order */ static struct ttm_pool_type *ttm_pool_select_type(struct ttm_pool *pool, enum ttm_caching caching, unsigned int order) { if (pool->use_dma_alloc) return &pool->caching[caching].orders[order]; #ifdef CONFIG_X86 switch (caching) { case ttm_write_combined: if (pool->use_dma32) return &global_dma32_write_combined[order]; return &global_write_combined[order]; case ttm_uncached: if (pool->use_dma32) return &global_dma32_uncached[order]; return &global_uncached[order]; default: break; } #endif return NULL; } /* Free pages using the global shrinker list */ static unsigned int ttm_pool_shrink(void) { struct ttm_pool_type *pt; unsigned int num_freed; struct page *p; mutex_lock(&shrinker_lock); pt = list_first_entry(&shrinker_list, typeof(*pt), shrinker_list); p = ttm_pool_type_take(pt); if (p) { ttm_pool_free_page(pt->pool, pt->caching, pt->order, p); num_freed = 1 << pt->order; } else { num_freed = 0; } list_move_tail(&pt->shrinker_list, &shrinker_list); mutex_unlock(&shrinker_lock); return num_freed; } /* Return the allocation order based for a page */ static unsigned int ttm_pool_page_order(struct ttm_pool *pool, struct page *p) { if (pool->use_dma_alloc) { struct ttm_pool_dma *dma = (void *)p->private; return dma->vaddr & ~PAGE_MASK; } return p->private; } /* Called when we got a page, either from a pool or newly allocated */ static int ttm_pool_page_allocated(struct ttm_pool *pool, unsigned int order, struct page *p, dma_addr_t **dma_addr, unsigned long *num_pages, struct page ***pages) { unsigned int i; int r; if (*dma_addr) { r = ttm_pool_map(pool, order, p, dma_addr); if (r) return r; } *num_pages -= 1 << order; for (i = 1 << order; i; --i, ++(*pages), ++p) **pages = p; return 0; } /** * ttm_pool_free_range() - Free a range of TTM pages * @pool: The pool used for allocating. * @tt: The struct ttm_tt holding the page pointers. * @caching: The page caching mode used by the range. * @start_page: index for first page to free. * @end_page: index for last page to free + 1. * * During allocation the ttm_tt page-vector may be populated with ranges of * pages with different attributes if allocation hit an error without being * able to completely fulfill the allocation. This function can be used * to free these individual ranges. */ static void ttm_pool_free_range(struct ttm_pool *pool, struct ttm_tt *tt, enum ttm_caching caching, pgoff_t start_page, pgoff_t end_page) { struct page **pages = &tt->pages[start_page]; unsigned int order; pgoff_t i, nr; for (i = start_page; i < end_page; i += nr, pages += nr) { struct ttm_pool_type *pt = NULL; order = ttm_pool_page_order(pool, *pages); nr = (1UL << order); if (tt->dma_address) ttm_pool_unmap(pool, tt->dma_address[i], nr); pt = ttm_pool_select_type(pool, caching, order); if (pt) ttm_pool_type_give(pt, *pages); else ttm_pool_free_page(pool, caching, order, *pages); } } /** * ttm_pool_alloc - Fill a ttm_tt object * * @pool: ttm_pool to use * @tt: ttm_tt object to fill * @ctx: operation context * * Fill the ttm_tt object with pages and also make sure to DMA map them when * necessary. * * Returns: 0 on successe, negative error code otherwise. */ int ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt, struct ttm_operation_ctx *ctx) { pgoff_t num_pages = tt->num_pages; dma_addr_t *dma_addr = tt->dma_address; struct page **caching = tt->pages; struct page **pages = tt->pages; enum ttm_caching page_caching; gfp_t gfp_flags = GFP_USER; pgoff_t caching_divide; unsigned int order; struct page *p; int r; WARN_ON(!num_pages || ttm_tt_is_populated(tt)); WARN_ON(dma_addr && !pool->dev); if (tt->page_flags & TTM_PAGE_FLAG_ZERO_ALLOC) gfp_flags |= __GFP_ZERO; if (ctx->gfp_retry_mayfail) gfp_flags |= __GFP_RETRY_MAYFAIL; if (pool->use_dma32) gfp_flags |= GFP_DMA32; else gfp_flags |= GFP_HIGHUSER; for (order = min_t(unsigned int, MAX_ORDER - 1, __fls(num_pages)); num_pages; order = min_t(unsigned int, order, __fls(num_pages))) { struct ttm_pool_type *pt; page_caching = tt->caching; pt = ttm_pool_select_type(pool, tt->caching, order); p = pt ? ttm_pool_type_take(pt) : NULL; if (p) { r = ttm_pool_apply_caching(caching, pages, tt->caching); if (r) goto error_free_page; caching = pages; do { r = ttm_pool_page_allocated(pool, order, p, &dma_addr, &num_pages, &pages); if (r) goto error_free_page; caching = pages; if (num_pages < (1 << order)) break; p = ttm_pool_type_take(pt); } while (p); } page_caching = ttm_cached; while (num_pages >= (1 << order) && (p = ttm_pool_alloc_page(pool, gfp_flags, order))) { if (PageHighMem(p)) { r = ttm_pool_apply_caching(caching, pages, tt->caching); if (r) goto error_free_page; caching = pages; } r = ttm_pool_page_allocated(pool, order, p, &dma_addr, &num_pages, &pages); if (r) goto error_free_page; if (PageHighMem(p)) caching = pages; } if (!p) { if (order) { --order; continue; } r = -ENOMEM; goto error_free_all; } } r = ttm_pool_apply_caching(caching, pages, tt->caching); if (r) goto error_free_all; return 0; error_free_page: ttm_pool_free_page(pool, page_caching, order, p); error_free_all: num_pages = tt->num_pages - num_pages; caching_divide = caching - tt->pages; ttm_pool_free_range(pool, tt, tt->caching, 0, caching_divide); ttm_pool_free_range(pool, tt, ttm_cached, caching_divide, num_pages); return r; } EXPORT_SYMBOL(ttm_pool_alloc); /** * ttm_pool_free - Free the backing pages from a ttm_tt object * * @pool: Pool to give pages back to. * @tt: ttm_tt object to unpopulate * * Give the packing pages back to a pool or free them */ void ttm_pool_free(struct ttm_pool *pool, struct ttm_tt *tt) { ttm_pool_free_range(pool, tt, tt->caching, 0, tt->num_pages); while (atomic_long_read(&allocated_pages) > page_pool_size) ttm_pool_shrink(); } EXPORT_SYMBOL(ttm_pool_free); /** * ttm_pool_init - Initialize a pool * * @pool: the pool to initialize * @dev: device for DMA allocations and mappings * @use_dma_alloc: true if coherent DMA alloc should be used * @use_dma32: true if GFP_DMA32 should be used * * Initialize the pool and its pool types. */ void ttm_pool_init(struct ttm_pool *pool, struct device *dev, bool use_dma_alloc, bool use_dma32) { unsigned int i, j; WARN_ON(!dev && use_dma_alloc); pool->dev = dev; pool->use_dma_alloc = use_dma_alloc; pool->use_dma32 = use_dma32; if (use_dma_alloc) { for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i) for (j = 0; j < MAX_ORDER; ++j) ttm_pool_type_init(&pool->caching[i].orders[j], pool, i, j); } } /** * ttm_pool_fini - Cleanup a pool * * @pool: the pool to clean up * * Free all pages in the pool and unregister the types from the global * shrinker. */ void ttm_pool_fini(struct ttm_pool *pool) { unsigned int i, j; if (pool->use_dma_alloc) { for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i) for (j = 0; j < MAX_ORDER; ++j) ttm_pool_type_fini(&pool->caching[i].orders[j]); } } /* As long as pages are available make sure to release at least one */ static unsigned long ttm_pool_shrinker_scan(struct shrinker *shrink, struct shrink_control *sc) { unsigned long num_freed = 0; do num_freed += ttm_pool_shrink(); while (!num_freed && atomic_long_read(&allocated_pages)); return num_freed; } /* Return the number of pages available or SHRINK_EMPTY if we have none */ static unsigned long ttm_pool_shrinker_count(struct shrinker *shrink, struct shrink_control *sc) { unsigned long num_pages = atomic_long_read(&allocated_pages); return num_pages ? num_pages : SHRINK_EMPTY; } #ifdef CONFIG_DEBUG_FS /* Count the number of pages available in a pool_type */ static unsigned int ttm_pool_type_count(struct ttm_pool_type *pt) { unsigned int count = 0; struct page *p; spin_lock(&pt->lock); /* Only used for debugfs, the overhead doesn't matter */ list_for_each_entry(p, &pt->pages, lru) ++count; spin_unlock(&pt->lock); return count; } /* Print a nice header for the order */ static void ttm_pool_debugfs_header(struct seq_file *m) { unsigned int i; seq_puts(m, "\t "); for (i = 0; i < MAX_ORDER; ++i) seq_printf(m, " ---%2u---", i); seq_puts(m, "\n"); } /* Dump information about the different pool types */ static void ttm_pool_debugfs_orders(struct ttm_pool_type *pt, struct seq_file *m) { unsigned int i; for (i = 0; i < MAX_ORDER; ++i) seq_printf(m, " %8u", ttm_pool_type_count(&pt[i])); seq_puts(m, "\n"); } /* Dump the total amount of allocated pages */ static void ttm_pool_debugfs_footer(struct seq_file *m) { seq_printf(m, "\ntotal\t: %8lu of %8lu\n", atomic_long_read(&allocated_pages), page_pool_size); } /* Dump the information for the global pools */ static int ttm_pool_debugfs_globals_show(struct seq_file *m, void *data) { ttm_pool_debugfs_header(m); mutex_lock(&shrinker_lock); seq_puts(m, "wc\t:"); ttm_pool_debugfs_orders(global_write_combined, m); seq_puts(m, "uc\t:"); ttm_pool_debugfs_orders(global_uncached, m); seq_puts(m, "wc 32\t:"); ttm_pool_debugfs_orders(global_dma32_write_combined, m); seq_puts(m, "uc 32\t:"); ttm_pool_debugfs_orders(global_dma32_uncached, m); mutex_unlock(&shrinker_lock); ttm_pool_debugfs_footer(m); return 0; } DEFINE_SHOW_ATTRIBUTE(ttm_pool_debugfs_globals); /** * ttm_pool_debugfs - Debugfs dump function for a pool * * @pool: the pool to dump the information for * @m: seq_file to dump to * * Make a debugfs dump with the per pool and global information. */ int ttm_pool_debugfs(struct ttm_pool *pool, struct seq_file *m) { unsigned int i; if (!pool->use_dma_alloc) { seq_puts(m, "unused\n"); return 0; } ttm_pool_debugfs_header(m); mutex_lock(&shrinker_lock); for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i) { seq_puts(m, "DMA "); switch (i) { case ttm_cached: seq_puts(m, "\t:"); break; case ttm_write_combined: seq_puts(m, "wc\t:"); break; case ttm_uncached: seq_puts(m, "uc\t:"); break; } ttm_pool_debugfs_orders(pool->caching[i].orders, m); } mutex_unlock(&shrinker_lock); ttm_pool_debugfs_footer(m); return 0; } EXPORT_SYMBOL(ttm_pool_debugfs); /* Test the shrinker functions and dump the result */ static int ttm_pool_debugfs_shrink_show(struct seq_file *m, void *data) { struct shrink_control sc = { .gfp_mask = GFP_NOFS }; fs_reclaim_acquire(GFP_KERNEL); seq_printf(m, "%lu/%lu\n", ttm_pool_shrinker_count(&mm_shrinker, &sc), ttm_pool_shrinker_scan(&mm_shrinker, &sc)); fs_reclaim_release(GFP_KERNEL); return 0; } DEFINE_SHOW_ATTRIBUTE(ttm_pool_debugfs_shrink); #endif /** * ttm_pool_mgr_init - Initialize globals * * @num_pages: default number of pages * * Initialize the global locks and lists for the MM shrinker. */ int ttm_pool_mgr_init(unsigned long num_pages) { unsigned int i; if (!page_pool_size) page_pool_size = num_pages; mutex_init(&shrinker_lock); INIT_LIST_HEAD(&shrinker_list); for (i = 0; i < MAX_ORDER; ++i) { ttm_pool_type_init(&global_write_combined[i], NULL, ttm_write_combined, i); ttm_pool_type_init(&global_uncached[i], NULL, ttm_uncached, i); ttm_pool_type_init(&global_dma32_write_combined[i], NULL, ttm_write_combined, i); ttm_pool_type_init(&global_dma32_uncached[i], NULL, ttm_uncached, i); } #ifdef CONFIG_DEBUG_FS debugfs_create_file("page_pool", 0444, ttm_debugfs_root, NULL, &ttm_pool_debugfs_globals_fops); debugfs_create_file("page_pool_shrink", 0400, ttm_debugfs_root, NULL, &ttm_pool_debugfs_shrink_fops); #endif mm_shrinker.count_objects = ttm_pool_shrinker_count; mm_shrinker.scan_objects = ttm_pool_shrinker_scan; mm_shrinker.seeks = 1; return register_shrinker(&mm_shrinker); } /** * ttm_pool_mgr_fini - Finalize globals * * Cleanup the global pools and unregister the MM shrinker. */ void ttm_pool_mgr_fini(void) { unsigned int i; for (i = 0; i < MAX_ORDER; ++i) { ttm_pool_type_fini(&global_write_combined[i]); ttm_pool_type_fini(&global_uncached[i]); ttm_pool_type_fini(&global_dma32_write_combined[i]); ttm_pool_type_fini(&global_dma32_uncached[i]); } unregister_shrinker(&mm_shrinker); WARN_ON(!list_empty(&shrinker_list)); }