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/*
* Copyright 2010 Marek Olšák <maraeo@gmail.com>
* Copyright 2016 Advanced Micro Devices, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* on the rights to use, copy, modify, merge, publish, distribute, sub
* license, and/or sell copies of the Software, and to permit persons to whom
* the Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
* THE AUTHOR(S) AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
* USE OR OTHER DEALINGS IN THE SOFTWARE. */
/**
* Slab allocator for equally sized memory allocations.
*
* Objects are allocated from "child" pools that are connected to a "parent"
* pool.
*
* Calls to slab_alloc/slab_free for the same child pool must not occur from
* multiple threads simultaneously.
*
* Allocations obtained from one child pool should usually be freed in the
* same child pool. Freeing an allocation in a different child pool associated
* to the same parent is allowed (and requires no locking by the caller), but
* it is discouraged because it implies a performance penalty.
*
* For convenience and to ease the transition, there is also a set of wrapper
* functions around a single parent-child pair.
*/
#ifndef SLAB_H
#define SLAB_H
#include "c11/threads.h"
struct slab_element_header;
struct slab_page_header;
struct slab_parent_pool {
mtx_t mutex;
unsigned element_size;
unsigned num_elements;
};
struct slab_child_pool {
struct slab_parent_pool *parent;
struct slab_page_header *pages;
/* Free elements. */
struct slab_element_header *free;
/* Elements that are owned by this pool but were freed with a different
* pool as the argument to slab_free.
*
* This list is protected by the parent mutex.
*/
struct slab_element_header *migrated;
};
void slab_create_parent(struct slab_parent_pool *parent,
unsigned item_size,
unsigned num_items);
void slab_destroy_parent(struct slab_parent_pool *parent);
void slab_create_child(struct slab_child_pool *pool,
struct slab_parent_pool *parent);
void slab_destroy_child(struct slab_child_pool *pool);
void *slab_alloc(struct slab_child_pool *pool);
void slab_free(struct slab_child_pool *pool, void *ptr);
struct slab_mempool {
struct slab_parent_pool parent;
struct slab_child_pool child;
};
void slab_create(struct slab_mempool *pool,
unsigned item_size,
unsigned num_items);
void slab_destroy(struct slab_mempool *pool);
void *slab_alloc_st(struct slab_mempool *pool);
void slab_free_st(struct slab_mempool *pool, void *ptr);
#endif
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