422 lines
8.6 KiB
C
422 lines
8.6 KiB
C
// SPDX-License-Identifier: MIT
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/*
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* Copyright © 2021 Intel Corporation
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*/
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#include <linux/kmemleak.h>
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#include "i915_buddy.h"
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#include "i915_gem.h"
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#include "i915_utils.h"
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static struct kmem_cache *slab_blocks;
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static struct i915_buddy_block *i915_block_alloc(struct i915_buddy_mm *mm,
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struct i915_buddy_block *parent,
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unsigned int order,
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u64 offset)
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{
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struct i915_buddy_block *block;
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GEM_BUG_ON(order > I915_BUDDY_MAX_ORDER);
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block = kmem_cache_zalloc(slab_blocks, GFP_KERNEL);
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if (!block)
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return NULL;
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block->header = offset;
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block->header |= order;
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block->parent = parent;
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GEM_BUG_ON(block->header & I915_BUDDY_HEADER_UNUSED);
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return block;
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}
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static void i915_block_free(struct i915_buddy_mm *mm,
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struct i915_buddy_block *block)
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{
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kmem_cache_free(slab_blocks, block);
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}
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static void mark_allocated(struct i915_buddy_block *block)
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{
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block->header &= ~I915_BUDDY_HEADER_STATE;
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block->header |= I915_BUDDY_ALLOCATED;
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list_del(&block->link);
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}
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static void mark_free(struct i915_buddy_mm *mm,
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struct i915_buddy_block *block)
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{
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block->header &= ~I915_BUDDY_HEADER_STATE;
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block->header |= I915_BUDDY_FREE;
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list_add(&block->link,
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&mm->free_list[i915_buddy_block_order(block)]);
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}
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static void mark_split(struct i915_buddy_block *block)
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{
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block->header &= ~I915_BUDDY_HEADER_STATE;
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block->header |= I915_BUDDY_SPLIT;
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list_del(&block->link);
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}
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int i915_buddy_init(struct i915_buddy_mm *mm, u64 size, u64 chunk_size)
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{
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unsigned int i;
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u64 offset;
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if (size < chunk_size)
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return -EINVAL;
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if (chunk_size < PAGE_SIZE)
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return -EINVAL;
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if (!is_power_of_2(chunk_size))
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return -EINVAL;
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size = round_down(size, chunk_size);
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mm->size = size;
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mm->chunk_size = chunk_size;
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mm->max_order = ilog2(size) - ilog2(chunk_size);
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GEM_BUG_ON(mm->max_order > I915_BUDDY_MAX_ORDER);
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mm->free_list = kmalloc_array(mm->max_order + 1,
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sizeof(struct list_head),
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GFP_KERNEL);
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if (!mm->free_list)
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return -ENOMEM;
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for (i = 0; i <= mm->max_order; ++i)
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INIT_LIST_HEAD(&mm->free_list[i]);
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mm->n_roots = hweight64(size);
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mm->roots = kmalloc_array(mm->n_roots,
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sizeof(struct i915_buddy_block *),
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GFP_KERNEL);
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if (!mm->roots)
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goto out_free_list;
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offset = 0;
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i = 0;
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/*
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* Split into power-of-two blocks, in case we are given a size that is
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* not itself a power-of-two.
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*/
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do {
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struct i915_buddy_block *root;
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unsigned int order;
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u64 root_size;
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root_size = rounddown_pow_of_two(size);
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order = ilog2(root_size) - ilog2(chunk_size);
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root = i915_block_alloc(mm, NULL, order, offset);
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if (!root)
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goto out_free_roots;
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mark_free(mm, root);
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GEM_BUG_ON(i > mm->max_order);
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GEM_BUG_ON(i915_buddy_block_size(mm, root) < chunk_size);
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mm->roots[i] = root;
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offset += root_size;
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size -= root_size;
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i++;
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} while (size);
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return 0;
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out_free_roots:
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while (i--)
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i915_block_free(mm, mm->roots[i]);
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kfree(mm->roots);
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out_free_list:
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kfree(mm->free_list);
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return -ENOMEM;
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}
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void i915_buddy_fini(struct i915_buddy_mm *mm)
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{
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int i;
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for (i = 0; i < mm->n_roots; ++i) {
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GEM_WARN_ON(!i915_buddy_block_is_free(mm->roots[i]));
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i915_block_free(mm, mm->roots[i]);
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}
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kfree(mm->roots);
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kfree(mm->free_list);
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}
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static int split_block(struct i915_buddy_mm *mm,
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struct i915_buddy_block *block)
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{
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unsigned int block_order = i915_buddy_block_order(block) - 1;
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u64 offset = i915_buddy_block_offset(block);
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GEM_BUG_ON(!i915_buddy_block_is_free(block));
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GEM_BUG_ON(!i915_buddy_block_order(block));
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block->left = i915_block_alloc(mm, block, block_order, offset);
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if (!block->left)
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return -ENOMEM;
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block->right = i915_block_alloc(mm, block, block_order,
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offset + (mm->chunk_size << block_order));
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if (!block->right) {
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i915_block_free(mm, block->left);
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return -ENOMEM;
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}
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mark_free(mm, block->left);
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mark_free(mm, block->right);
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mark_split(block);
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return 0;
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}
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static struct i915_buddy_block *
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get_buddy(struct i915_buddy_block *block)
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{
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struct i915_buddy_block *parent;
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parent = block->parent;
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if (!parent)
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return NULL;
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if (parent->left == block)
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return parent->right;
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return parent->left;
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}
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static void __i915_buddy_free(struct i915_buddy_mm *mm,
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struct i915_buddy_block *block)
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{
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struct i915_buddy_block *parent;
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while ((parent = block->parent)) {
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struct i915_buddy_block *buddy;
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buddy = get_buddy(block);
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if (!i915_buddy_block_is_free(buddy))
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break;
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list_del(&buddy->link);
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i915_block_free(mm, block);
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i915_block_free(mm, buddy);
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block = parent;
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}
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mark_free(mm, block);
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}
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void i915_buddy_free(struct i915_buddy_mm *mm,
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struct i915_buddy_block *block)
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{
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GEM_BUG_ON(!i915_buddy_block_is_allocated(block));
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__i915_buddy_free(mm, block);
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}
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void i915_buddy_free_list(struct i915_buddy_mm *mm, struct list_head *objects)
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{
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struct i915_buddy_block *block, *on;
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list_for_each_entry_safe(block, on, objects, link) {
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i915_buddy_free(mm, block);
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cond_resched();
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}
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INIT_LIST_HEAD(objects);
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}
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/*
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* Allocate power-of-two block. The order value here translates to:
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*
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* 0 = 2^0 * mm->chunk_size
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* 1 = 2^1 * mm->chunk_size
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* 2 = 2^2 * mm->chunk_size
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* ...
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*/
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struct i915_buddy_block *
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i915_buddy_alloc(struct i915_buddy_mm *mm, unsigned int order)
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{
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struct i915_buddy_block *block = NULL;
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unsigned int i;
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int err;
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for (i = order; i <= mm->max_order; ++i) {
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block = list_first_entry_or_null(&mm->free_list[i],
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struct i915_buddy_block,
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link);
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if (block)
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break;
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}
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if (!block)
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return ERR_PTR(-ENOSPC);
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GEM_BUG_ON(!i915_buddy_block_is_free(block));
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while (i != order) {
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err = split_block(mm, block);
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if (unlikely(err))
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goto out_free;
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/* Go low */
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block = block->left;
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i--;
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}
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mark_allocated(block);
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kmemleak_update_trace(block);
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return block;
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out_free:
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if (i != order)
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__i915_buddy_free(mm, block);
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return ERR_PTR(err);
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}
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static inline bool overlaps(u64 s1, u64 e1, u64 s2, u64 e2)
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{
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return s1 <= e2 && e1 >= s2;
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}
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static inline bool contains(u64 s1, u64 e1, u64 s2, u64 e2)
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{
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return s1 <= s2 && e1 >= e2;
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}
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/*
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* Allocate range. Note that it's safe to chain together multiple alloc_ranges
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* with the same blocks list.
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*
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* Intended for pre-allocating portions of the address space, for example to
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* reserve a block for the initial framebuffer or similar, hence the expectation
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* here is that i915_buddy_alloc() is still the main vehicle for
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* allocations, so if that's not the case then the drm_mm range allocator is
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* probably a much better fit, and so you should probably go use that instead.
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*/
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int i915_buddy_alloc_range(struct i915_buddy_mm *mm,
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struct list_head *blocks,
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u64 start, u64 size)
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{
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struct i915_buddy_block *block;
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struct i915_buddy_block *buddy;
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LIST_HEAD(allocated);
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LIST_HEAD(dfs);
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u64 end;
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int err;
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int i;
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if (size < mm->chunk_size)
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return -EINVAL;
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if (!IS_ALIGNED(size | start, mm->chunk_size))
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return -EINVAL;
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if (range_overflows(start, size, mm->size))
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return -EINVAL;
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for (i = 0; i < mm->n_roots; ++i)
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list_add_tail(&mm->roots[i]->tmp_link, &dfs);
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end = start + size - 1;
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do {
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u64 block_start;
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u64 block_end;
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block = list_first_entry_or_null(&dfs,
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struct i915_buddy_block,
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tmp_link);
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if (!block)
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break;
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list_del(&block->tmp_link);
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block_start = i915_buddy_block_offset(block);
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block_end = block_start + i915_buddy_block_size(mm, block) - 1;
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if (!overlaps(start, end, block_start, block_end))
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continue;
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if (i915_buddy_block_is_allocated(block)) {
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err = -ENOSPC;
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goto err_free;
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}
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if (contains(start, end, block_start, block_end)) {
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if (!i915_buddy_block_is_free(block)) {
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err = -ENOSPC;
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goto err_free;
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}
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mark_allocated(block);
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list_add_tail(&block->link, &allocated);
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continue;
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}
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if (!i915_buddy_block_is_split(block)) {
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err = split_block(mm, block);
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if (unlikely(err))
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goto err_undo;
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}
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list_add(&block->right->tmp_link, &dfs);
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list_add(&block->left->tmp_link, &dfs);
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} while (1);
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list_splice_tail(&allocated, blocks);
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return 0;
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err_undo:
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/*
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* We really don't want to leave around a bunch of split blocks, since
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* bigger is better, so make sure we merge everything back before we
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* free the allocated blocks.
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*/
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buddy = get_buddy(block);
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if (buddy &&
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(i915_buddy_block_is_free(block) &&
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i915_buddy_block_is_free(buddy)))
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__i915_buddy_free(mm, block);
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err_free:
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i915_buddy_free_list(mm, &allocated);
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return err;
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}
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#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
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#include "selftests/i915_buddy.c"
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#endif
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void i915_buddy_module_exit(void)
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{
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kmem_cache_destroy(slab_blocks);
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}
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int __init i915_buddy_module_init(void)
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{
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slab_blocks = KMEM_CACHE(i915_buddy_block, 0);
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if (!slab_blocks)
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return -ENOMEM;
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return 0;
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}
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