136 lines
3.5 KiB
C
136 lines
3.5 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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#ifndef __I915_BUDDY_H__
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#define __I915_BUDDY_H__
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#include <linux/bitops.h>
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#include <linux/list.h>
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#include <linux/slab.h>
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struct i915_buddy_block {
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#define I915_BUDDY_HEADER_OFFSET GENMASK_ULL(63, 12)
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#define I915_BUDDY_HEADER_STATE GENMASK_ULL(11, 10)
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#define I915_BUDDY_ALLOCATED (1 << 10)
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#define I915_BUDDY_FREE (2 << 10)
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#define I915_BUDDY_SPLIT (3 << 10)
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/* Free to be used, if needed in the future */
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#define I915_BUDDY_HEADER_UNUSED GENMASK_ULL(9, 6)
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#define I915_BUDDY_HEADER_ORDER GENMASK_ULL(5, 0)
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u64 header;
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struct i915_buddy_block *left;
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struct i915_buddy_block *right;
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struct i915_buddy_block *parent;
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void *private; /* owned by creator */
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/*
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* While the block is allocated by the user through i915_buddy_alloc*,
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* the user has ownership of the link, for example to maintain within
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* a list, if so desired. As soon as the block is freed with
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* i915_buddy_free* ownership is given back to the mm.
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*/
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struct list_head link;
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struct list_head tmp_link;
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};
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/* Order-zero must be at least PAGE_SIZE */
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#define I915_BUDDY_MAX_ORDER (63 - PAGE_SHIFT)
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/*
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* Binary Buddy System.
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*
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* Locking should be handled by the user, a simple mutex around
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* i915_buddy_alloc* and i915_buddy_free* should suffice.
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*/
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struct i915_buddy_mm {
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/* Maintain a free list for each order. */
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struct list_head *free_list;
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/*
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* Maintain explicit binary tree(s) to track the allocation of the
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* address space. This gives us a simple way of finding a buddy block
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* and performing the potentially recursive merge step when freeing a
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* block. Nodes are either allocated or free, in which case they will
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* also exist on the respective free list.
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*/
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struct i915_buddy_block **roots;
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/*
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* Anything from here is public, and remains static for the lifetime of
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* the mm. Everything above is considered do-not-touch.
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*/
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unsigned int n_roots;
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unsigned int max_order;
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/* Must be at least PAGE_SIZE */
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u64 chunk_size;
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u64 size;
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};
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static inline u64
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i915_buddy_block_offset(struct i915_buddy_block *block)
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{
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return block->header & I915_BUDDY_HEADER_OFFSET;
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}
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static inline unsigned int
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i915_buddy_block_order(struct i915_buddy_block *block)
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{
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return block->header & I915_BUDDY_HEADER_ORDER;
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}
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static inline unsigned int
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i915_buddy_block_state(struct i915_buddy_block *block)
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{
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return block->header & I915_BUDDY_HEADER_STATE;
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}
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static inline bool
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i915_buddy_block_is_allocated(struct i915_buddy_block *block)
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{
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return i915_buddy_block_state(block) == I915_BUDDY_ALLOCATED;
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}
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static inline bool
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i915_buddy_block_is_free(struct i915_buddy_block *block)
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{
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return i915_buddy_block_state(block) == I915_BUDDY_FREE;
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}
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static inline bool
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i915_buddy_block_is_split(struct i915_buddy_block *block)
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{
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return i915_buddy_block_state(block) == I915_BUDDY_SPLIT;
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}
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static inline u64
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i915_buddy_block_size(struct i915_buddy_mm *mm,
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struct i915_buddy_block *block)
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{
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return mm->chunk_size << i915_buddy_block_order(block);
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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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void i915_buddy_fini(struct i915_buddy_mm *mm);
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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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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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void i915_buddy_free(struct i915_buddy_mm *mm, struct i915_buddy_block *block);
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void i915_buddy_free_list(struct i915_buddy_mm *mm, struct list_head *objects);
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void i915_buddy_module_exit(void);
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int i915_buddy_module_init(void);
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#endif
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