1 /* 2 * Copyright 2010 Marek Olšák <maraeo@gmail.com> 3 * Copyright 2016 Advanced Micro Devices, Inc. 4 * 5 * Permission is hereby granted, free of charge, to any person obtaining a 6 * copy of this software and associated documentation files (the "Software"), 7 * to deal in the Software without restriction, including without limitation 8 * on the rights to use, copy, modify, merge, publish, distribute, sub 9 * license, and/or sell copies of the Software, and to permit persons to whom 10 * the Software is furnished to do so, subject to the following conditions: 11 * 12 * The above copyright notice and this permission notice (including the next 13 * paragraph) shall be included in all copies or substantial portions of the 14 * Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL 19 * THE AUTHOR(S) AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM, 20 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR 21 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE 22 * USE OR OTHER DEALINGS IN THE SOFTWARE. */ 23 24 /** 25 * Slab allocator for equally sized memory allocations. 26 * 27 * Objects are allocated from "child" pools that are connected to a "parent" 28 * pool. 29 * 30 * Calls to slab_alloc/slab_free for the same child pool must not occur from 31 * multiple threads simultaneously. 32 * 33 * Allocations obtained from one child pool should usually be freed in the 34 * same child pool. Freeing an allocation in a different child pool associated 35 * to the same parent is allowed (and requires no locking by the caller), but 36 * it is discouraged because it implies a performance penalty. 37 * 38 * For convenience and to ease the transition, there is also a set of wrapper 39 * functions around a single parent-child pair. 40 */ 41 42 #ifndef SLAB_H 43 #define SLAB_H 44 45 #include "simple_mtx.h" 46 47 #ifdef __cplusplus 48 extern "C" { 49 #endif 50 51 struct slab_element_header; 52 struct slab_page_header; 53 54 struct slab_parent_pool { 55 simple_mtx_t mutex; 56 unsigned element_size; 57 unsigned num_elements; 58 }; 59 60 struct slab_child_pool { 61 struct slab_parent_pool *parent; 62 63 struct slab_page_header *pages; 64 65 /* Free elements. */ 66 struct slab_element_header *free; 67 68 /* Elements that are owned by this pool but were freed with a different 69 * pool as the argument to slab_free. 70 * 71 * This list is protected by the parent mutex. 72 */ 73 struct slab_element_header *migrated; 74 }; 75 76 void slab_create_parent(struct slab_parent_pool *parent, 77 unsigned item_size, 78 unsigned num_items); 79 void slab_destroy_parent(struct slab_parent_pool *parent); 80 void slab_create_child(struct slab_child_pool *pool, 81 struct slab_parent_pool *parent); 82 void slab_destroy_child(struct slab_child_pool *pool); 83 void *slab_alloc(struct slab_child_pool *pool); 84 void slab_free(struct slab_child_pool *pool, void *ptr); 85 86 struct slab_mempool { 87 struct slab_parent_pool parent; 88 struct slab_child_pool child; 89 }; 90 91 void slab_create(struct slab_mempool *mempool, 92 unsigned item_size, 93 unsigned num_items); 94 void slab_destroy(struct slab_mempool *mempool); 95 void *slab_alloc_st(struct slab_mempool *mempool); 96 void slab_free_st(struct slab_mempool *mempool, void *ptr); 97 98 #ifdef __cplusplus 99 } 100 #endif 101 102 #endif 103