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| 3770 | Serge | 1 | /* |
| 2 | * Copyright 2010 Marek Olšák |
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| 3 | * |
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| 4 | * Permission is hereby granted, free of charge, to any person obtaining a |
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| 5 | * copy of this software and associated documentation files (the "Software"), |
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| 6 | * to deal in the Software without restriction, including without limitation |
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| 7 | * on the rights to use, copy, modify, merge, publish, distribute, sub |
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| 8 | * license, and/or sell copies of the Software, and to permit persons to whom |
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| 9 | * the Software is furnished to do so, subject to the following conditions: |
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| 10 | * |
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| 11 | * The above copyright notice and this permission notice (including the next |
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| 12 | * paragraph) shall be included in all copies or substantial portions of the |
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| 13 | * Software. |
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| 14 | * |
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| 15 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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| 16 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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| 17 | * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL |
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| 18 | * THE AUTHOR(S) AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM, |
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| 19 | * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR |
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| 20 | * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE |
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| 21 | * USE OR OTHER DEALINGS IN THE SOFTWARE. */ |
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| 22 | |||
| 23 | /** |
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| 24 | * @file |
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| 25 | * Simple slab allocator for equally sized memory allocations. |
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| 26 | * util_slab_alloc and util_slab_free have time complexity in O(1). |
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| 27 | * |
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| 28 | * Good for allocations which have very low lifetime and are allocated |
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| 29 | * and freed very often. Use a profiler first to know if it's worth using it! |
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| 30 | * |
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| 31 | * Candidates: transfer_map |
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| 32 | * |
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| 33 | * @author Marek Olšák |
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| 34 | */ |
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| 35 | |||
| 36 | #ifndef U_SLAB_H |
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| 37 | #define U_SLAB_H |
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| 38 | |||
| 39 | #include "os/os_thread.h" |
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| 40 | |||
| 41 | enum util_slab_threading { |
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| 42 | UTIL_SLAB_SINGLETHREADED = FALSE, |
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| 43 | UTIL_SLAB_MULTITHREADED = TRUE |
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| 44 | }; |
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| 45 | |||
| 46 | /* The page is an array of blocks (allocations). */ |
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| 47 | struct util_slab_page { |
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| 48 | /* The header (linked-list pointers). */ |
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| 49 | struct util_slab_page *prev, *next; |
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| 50 | |||
| 51 | /* Memory after the last member is dedicated to the page itself. |
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| 52 | * The allocated size is always larger than this structure. */ |
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| 53 | }; |
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| 54 | |||
| 55 | struct util_slab_mempool { |
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| 56 | /* Public members. */ |
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| 57 | void *(*alloc)(struct util_slab_mempool *pool); |
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| 58 | void (*free)(struct util_slab_mempool *pool, void *ptr); |
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| 59 | |||
| 60 | /* Private members. */ |
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| 61 | struct util_slab_block *first_free; |
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| 62 | |||
| 63 | struct util_slab_page list; |
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| 64 | |||
| 65 | unsigned block_size; |
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| 66 | unsigned page_size; |
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| 67 | unsigned num_blocks; |
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| 68 | unsigned num_pages; |
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| 69 | enum util_slab_threading threading; |
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| 70 | |||
| 71 | pipe_mutex mutex; |
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| 72 | }; |
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| 73 | |||
| 74 | void util_slab_create(struct util_slab_mempool *pool, |
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| 75 | unsigned item_size, |
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| 76 | unsigned num_blocks, |
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| 77 | enum util_slab_threading threading); |
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| 78 | |||
| 79 | void util_slab_destroy(struct util_slab_mempool *pool); |
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| 80 | |||
| 81 | void util_slab_set_thread_safety(struct util_slab_mempool *pool, |
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| 82 | enum util_slab_threading threading); |
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| 83 | |||
| 84 | #define util_slab_alloc(pool) (pool)->alloc(pool) |
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| 85 | #define util_slab_free(pool, ptr) (pool)->free(pool, ptr) |
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| 86 | |||
| 87 | #endif |