diff options
Diffstat (limited to 'drivers/gpu/drm/drm_buddy.c')
| -rw-r--r-- | drivers/gpu/drm/drm_buddy.c | 535 |
1 files changed, 535 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c new file mode 100644 index 000000000000..d60878bc9c20 --- /dev/null +++ b/drivers/gpu/drm/drm_buddy.c @@ -0,0 +1,535 @@ +// SPDX-License-Identifier: MIT +/* + * Copyright © 2021 Intel Corporation + */ + +#include <linux/kmemleak.h> +#include <linux/module.h> +#include <linux/sizes.h> + +#include <drm/drm_buddy.h> + +static struct kmem_cache *slab_blocks; + +static struct drm_buddy_block *drm_block_alloc(struct drm_buddy *mm, + struct drm_buddy_block *parent, + unsigned int order, + u64 offset) +{ + struct drm_buddy_block *block; + + BUG_ON(order > DRM_BUDDY_MAX_ORDER); + + block = kmem_cache_zalloc(slab_blocks, GFP_KERNEL); + if (!block) + return NULL; + + block->header = offset; + block->header |= order; + block->parent = parent; + + BUG_ON(block->header & DRM_BUDDY_HEADER_UNUSED); + return block; +} + +static void drm_block_free(struct drm_buddy *mm, + struct drm_buddy_block *block) +{ + kmem_cache_free(slab_blocks, block); +} + +static void mark_allocated(struct drm_buddy_block *block) +{ + block->header &= ~DRM_BUDDY_HEADER_STATE; + block->header |= DRM_BUDDY_ALLOCATED; + + list_del(&block->link); +} + +static void mark_free(struct drm_buddy *mm, + struct drm_buddy_block *block) +{ + block->header &= ~DRM_BUDDY_HEADER_STATE; + block->header |= DRM_BUDDY_FREE; + + list_add(&block->link, + &mm->free_list[drm_buddy_block_order(block)]); +} + +static void mark_split(struct drm_buddy_block *block) +{ + block->header &= ~DRM_BUDDY_HEADER_STATE; + block->header |= DRM_BUDDY_SPLIT; + + list_del(&block->link); +} + +/** + * drm_buddy_init - init memory manager + * + * @mm: DRM buddy manager to initialize + * @size: size in bytes to manage + * @chunk_size: minimum page size in bytes for our allocations + * + * Initializes the memory manager and its resources. + * + * Returns: + * 0 on success, error code on failure. + */ +int drm_buddy_init(struct drm_buddy *mm, u64 size, u64 chunk_size) +{ + unsigned int i; + u64 offset; + + if (size < chunk_size) + return -EINVAL; + + if (chunk_size < PAGE_SIZE) + return -EINVAL; + + if (!is_power_of_2(chunk_size)) + return -EINVAL; + + size = round_down(size, chunk_size); + + mm->size = size; + mm->avail = size; + mm->chunk_size = chunk_size; + mm->max_order = ilog2(size) - ilog2(chunk_size); + + BUG_ON(mm->max_order > DRM_BUDDY_MAX_ORDER); + + mm->free_list = kmalloc_array(mm->max_order + 1, + sizeof(struct list_head), + GFP_KERNEL); + if (!mm->free_list) + return -ENOMEM; + + for (i = 0; i <= mm->max_order; ++i) + INIT_LIST_HEAD(&mm->free_list[i]); + + mm->n_roots = hweight64(size); + + mm->roots = kmalloc_array(mm->n_roots, + sizeof(struct drm_buddy_block *), + GFP_KERNEL); + if (!mm->roots) + goto out_free_list; + + offset = 0; + i = 0; + + /* + * Split into power-of-two blocks, in case we are given a size that is + * not itself a power-of-two. + */ + do { + struct drm_buddy_block *root; + unsigned int order; + u64 root_size; + + root_size = rounddown_pow_of_two(size); + order = ilog2(root_size) - ilog2(chunk_size); + + root = drm_block_alloc(mm, NULL, order, offset); + if (!root) + goto out_free_roots; + + mark_free(mm, root); + + BUG_ON(i > mm->max_order); + BUG_ON(drm_buddy_block_size(mm, root) < chunk_size); + + mm->roots[i] = root; + + offset += root_size; + size -= root_size; + i++; + } while (size); + + return 0; + +out_free_roots: + while (i--) + drm_block_free(mm, mm->roots[i]); + kfree(mm->roots); +out_free_list: + kfree(mm->free_list); + return -ENOMEM; +} +EXPORT_SYMBOL(drm_buddy_init); + +/** + * drm_buddy_fini - tear down the memory manager + * + * @mm: DRM buddy manager to free + * + * Cleanup memory manager resources and the freelist + */ +void drm_buddy_fini(struct drm_buddy *mm) +{ + int i; + + for (i = 0; i < mm->n_roots; ++i) { + WARN_ON(!drm_buddy_block_is_free(mm->roots[i])); + drm_block_free(mm, mm->roots[i]); + } + + WARN_ON(mm->avail != mm->size); + + kfree(mm->roots); + kfree(mm->free_list); +} +EXPORT_SYMBOL(drm_buddy_fini); + +static int split_block(struct drm_buddy *mm, + struct drm_buddy_block *block) +{ + unsigned int block_order = drm_buddy_block_order(block) - 1; + u64 offset = drm_buddy_block_offset(block); + + BUG_ON(!drm_buddy_block_is_free(block)); + BUG_ON(!drm_buddy_block_order(block)); + + block->left = drm_block_alloc(mm, block, block_order, offset); + if (!block->left) + return -ENOMEM; + + block->right = drm_block_alloc(mm, block, block_order, + offset + (mm->chunk_size << block_order)); + if (!block->right) { + drm_block_free(mm, block->left); + return -ENOMEM; + } + + mark_free(mm, block->left); + mark_free(mm, block->right); + + mark_split(block); + + return 0; +} + +static struct drm_buddy_block * +get_buddy(struct drm_buddy_block *block) +{ + struct drm_buddy_block *parent; + + parent = block->parent; + if (!parent) + return NULL; + + if (parent->left == block) + return parent->right; + + return parent->left; +} + +static void __drm_buddy_free(struct drm_buddy *mm, + struct drm_buddy_block *block) +{ + struct drm_buddy_block *parent; + + while ((parent = block->parent)) { + struct drm_buddy_block *buddy; + + buddy = get_buddy(block); + + if (!drm_buddy_block_is_free(buddy)) + break; + + list_del(&buddy->link); + + drm_block_free(mm, block); + drm_block_free(mm, buddy); + + block = parent; + } + + mark_free(mm, block); +} + +/** + * drm_buddy_free_block - free a block + * + * @mm: DRM buddy manager + * @block: block to be freed + */ +void drm_buddy_free_block(struct drm_buddy *mm, + struct drm_buddy_block *block) +{ + BUG_ON(!drm_buddy_block_is_allocated(block)); + mm->avail += drm_buddy_block_size(mm, block); + __drm_buddy_free(mm, block); +} +EXPORT_SYMBOL(drm_buddy_free_block); + +/** + * drm_buddy_free_list - free blocks + * + * @mm: DRM buddy manager + * @objects: input list head to free blocks + */ +void drm_buddy_free_list(struct drm_buddy *mm, struct list_head *objects) +{ + struct drm_buddy_block *block, *on; + + list_for_each_entry_safe(block, on, objects, link) { + drm_buddy_free_block(mm, block); + cond_resched(); + } + INIT_LIST_HEAD(objects); +} +EXPORT_SYMBOL(drm_buddy_free_list); + +/** + * drm_buddy_alloc_blocks - allocate power-of-two blocks + * + * @mm: DRM buddy manager to allocate from + * @order: size of the allocation + * + * The order value here translates to: + * + * 0 = 2^0 * mm->chunk_size + * 1 = 2^1 * mm->chunk_size + * 2 = 2^2 * mm->chunk_size + * + * Returns: + * allocated ptr to the &drm_buddy_block on success + */ +struct drm_buddy_block * +drm_buddy_alloc_blocks(struct drm_buddy *mm, unsigned int order) +{ + struct drm_buddy_block *block = NULL; + unsigned int i; + int err; + + for (i = order; i <= mm->max_order; ++i) { + block = list_first_entry_or_null(&mm->free_list[i], + struct drm_buddy_block, + link); + if (block) + break; + } + + if (!block) + return ERR_PTR(-ENOSPC); + + BUG_ON(!drm_buddy_block_is_free(block)); + + while (i != order) { + err = split_block(mm, block); + if (unlikely(err)) + goto out_free; + + /* Go low */ + block = block->left; + i--; + } + + mark_allocated(block); + mm->avail -= drm_buddy_block_size(mm, block); + kmemleak_update_trace(block); + return block; + +out_free: + if (i != order) + __drm_buddy_free(mm, block); + return ERR_PTR(err); +} +EXPORT_SYMBOL(drm_buddy_alloc_blocks); + +static inline bool overlaps(u64 s1, u64 e1, u64 s2, u64 e2) +{ + return s1 <= e2 && e1 >= s2; +} + +static inline bool contains(u64 s1, u64 e1, u64 s2, u64 e2) +{ + return s1 <= s2 && e1 >= e2; +} + +/** + * drm_buddy_alloc_range - allocate range + * + * @mm: DRM buddy manager to allocate from + * @blocks: output list head to add allocated blocks + * @start: start of the allowed range for this block + * @size: size of the allocation + * + * Intended for pre-allocating portions of the address space, for example to + * reserve a block for the initial framebuffer or similar, hence the expectation + * here is that drm_buddy_alloc_blocks() is still the main vehicle for + * allocations, so if that's not the case then the drm_mm range allocator is + * probably a much better fit, and so you should probably go use that instead. + * + * Note that it's safe to chain together multiple alloc_ranges + * with the same blocks list + * + * Returns: + * 0 on success, error code on failure. + */ +int drm_buddy_alloc_range(struct drm_buddy *mm, + struct list_head *blocks, + u64 start, u64 size) +{ + struct drm_buddy_block *block; + struct drm_buddy_block *buddy; + LIST_HEAD(allocated); + LIST_HEAD(dfs); + u64 end; + int err; + int i; + + if (size < mm->chunk_size) + return -EINVAL; + + if (!IS_ALIGNED(size | start, mm->chunk_size)) + return -EINVAL; + + if (range_overflows(start, size, mm->size)) + return -EINVAL; + + for (i = 0; i < mm->n_roots; ++i) + list_add_tail(&mm->roots[i]->tmp_link, &dfs); + + end = start + size - 1; + + do { + u64 block_start; + u64 block_end; + + block = list_first_entry_or_null(&dfs, + struct drm_buddy_block, + tmp_link); + if (!block) + break; + + list_del(&block->tmp_link); + + block_start = drm_buddy_block_offset(block); + block_end = block_start + drm_buddy_block_size(mm, block) - 1; + + if (!overlaps(start, end, block_start, block_end)) + continue; + + if (drm_buddy_block_is_allocated(block)) { + err = -ENOSPC; + goto err_free; + } + + if (contains(start, end, block_start, block_end)) { + if (!drm_buddy_block_is_free(block)) { + err = -ENOSPC; + goto err_free; + } + + mark_allocated(block); + mm->avail -= drm_buddy_block_size(mm, block); + list_add_tail(&block->link, &allocated); + continue; + } + + if (!drm_buddy_block_is_split(block)) { + err = split_block(mm, block); + if (unlikely(err)) + goto err_undo; + } + + list_add(&block->right->tmp_link, &dfs); + list_add(&block->left->tmp_link, &dfs); + } while (1); + + list_splice_tail(&allocated, blocks); + return 0; + +err_undo: + /* + * We really don't want to leave around a bunch of split blocks, since + * bigger is better, so make sure we merge everything back before we + * free the allocated blocks. + */ + buddy = get_buddy(block); + if (buddy && + (drm_buddy_block_is_free(block) && + drm_buddy_block_is_free(buddy))) + __drm_buddy_free(mm, block); + +err_free: + drm_buddy_free_list(mm, &allocated); + return err; +} +EXPORT_SYMBOL(drm_buddy_alloc_range); + +/** + * drm_buddy_block_print - print block information + * + * @mm: DRM buddy manager + * @block: DRM buddy block + * @p: DRM printer to use + */ +void drm_buddy_block_print(struct drm_buddy *mm, + struct drm_buddy_block *block, + struct drm_printer *p) +{ + u64 start = drm_buddy_block_offset(block); + u64 size = drm_buddy_block_size(mm, block); + + drm_printf(p, "%#018llx-%#018llx: %llu\n", start, start + size, size); +} +EXPORT_SYMBOL(drm_buddy_block_print); + +/** + * drm_buddy_print - print allocator state + * + * @mm: DRM buddy manager + * @p: DRM printer to use + */ +void drm_buddy_print(struct drm_buddy *mm, struct drm_printer *p) +{ + int order; + + drm_printf(p, "chunk_size: %lluKiB, total: %lluMiB, free: %lluMiB\n", + mm->chunk_size >> 10, mm->size >> 20, mm->avail >> 20); + + for (order = mm->max_order; order >= 0; order--) { + struct drm_buddy_block *block; + u64 count = 0, free; + + list_for_each_entry(block, &mm->free_list[order], link) { + BUG_ON(!drm_buddy_block_is_free(block)); + count++; + } + + drm_printf(p, "order-%d ", order); + + free = count * (mm->chunk_size << order); + if (free < SZ_1M) + drm_printf(p, "free: %lluKiB", free >> 10); + else + drm_printf(p, "free: %lluMiB", free >> 20); + + drm_printf(p, ", pages: %llu\n", count); + } +} +EXPORT_SYMBOL(drm_buddy_print); + +static void drm_buddy_module_exit(void) +{ + kmem_cache_destroy(slab_blocks); +} + +static int __init drm_buddy_module_init(void) +{ + slab_blocks = KMEM_CACHE(drm_buddy_block, 0); + if (!slab_blocks) + return -ENOMEM; + + return 0; +} + +module_init(drm_buddy_module_init); +module_exit(drm_buddy_module_exit); + +MODULE_DESCRIPTION("DRM Buddy Allocator"); +MODULE_LICENSE("Dual MIT/GPL"); |