1 /* 2 * Copyright 2010 Marek Olk <maraeo (at) 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 "c11/threads.h" 46 47 struct slab_element_header; 48 struct slab_page_header; 49 50 struct slab_parent_pool { 51 mtx_t mutex; 52 unsigned element_size; 53 unsigned num_elements; 54 }; 55 56 struct slab_child_pool { 57 struct slab_parent_pool *parent; 58 59 struct slab_page_header *pages; 60 61 /* Free elements. */ 62 struct slab_element_header *free; 63 64 /* Elements that are owned by this pool but were freed with a different 65 * pool as the argument to slab_free. 66 * 67 * This list is protected by the parent mutex. 68 */ 69 struct slab_element_header *migrated; 70 }; 71 72 void slab_create_parent(struct slab_parent_pool *parent, 73 unsigned item_size, 74 unsigned num_items); 75 void slab_destroy_parent(struct slab_parent_pool *parent); 76 void slab_create_child(struct slab_child_pool *pool, 77 struct slab_parent_pool *parent); 78 void slab_destroy_child(struct slab_child_pool *pool); 79 void *slab_alloc(struct slab_child_pool *pool); 80 void slab_free(struct slab_child_pool *pool, void *ptr); 81 82 struct slab_mempool { 83 struct slab_parent_pool parent; 84 struct slab_child_pool child; 85 }; 86 87 void slab_create(struct slab_mempool *pool, 88 unsigned item_size, 89 unsigned num_items); 90 void slab_destroy(struct slab_mempool *pool); 91 void *slab_alloc_st(struct slab_mempool *pool); 92 void slab_free_st(struct slab_mempool *pool, void *ptr); 93 94 #endif 95
