88 lines
2.9 KiB
C
88 lines
2.9 KiB
C
/*
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* Copyright 2010 Marek Olšák <maraeo@gmail.com>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* on the rights to use, copy, modify, merge, publish, distribute, sub
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* license, and/or sell copies of the Software, and to permit persons to whom
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* the Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHOR(S) AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
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* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
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* USE OR OTHER DEALINGS IN THE SOFTWARE. */
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/**
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* @file
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* Simple slab allocator for equally sized memory allocations.
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* util_slab_alloc and util_slab_free have time complexity in O(1).
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*
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* Good for allocations which have very low lifetime and are allocated
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* and freed very often. Use a profiler first to know if it's worth using it!
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*
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* Candidates: transfer_map
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*
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* @author Marek Olšák
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*/
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#ifndef U_SLAB_H
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#define U_SLAB_H
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#include "os/os_thread.h"
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enum util_slab_threading {
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UTIL_SLAB_SINGLETHREADED = FALSE,
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UTIL_SLAB_MULTITHREADED = TRUE
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};
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/* The page is an array of blocks (allocations). */
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struct util_slab_page {
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/* The header (linked-list pointers). */
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struct util_slab_page *prev, *next;
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/* Memory after the last member is dedicated to the page itself.
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* The allocated size is always larger than this structure. */
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};
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struct util_slab_mempool {
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/* Public members. */
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void *(*alloc)(struct util_slab_mempool *pool);
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void (*free)(struct util_slab_mempool *pool, void *ptr);
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/* Private members. */
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struct util_slab_block *first_free;
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struct util_slab_page list;
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unsigned block_size;
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unsigned page_size;
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unsigned num_blocks;
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unsigned num_pages;
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enum util_slab_threading threading;
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pipe_mutex mutex;
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};
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void util_slab_create(struct util_slab_mempool *pool,
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unsigned item_size,
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unsigned num_blocks,
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enum util_slab_threading threading);
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void util_slab_destroy(struct util_slab_mempool *pool);
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void util_slab_set_thread_safety(struct util_slab_mempool *pool,
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enum util_slab_threading threading);
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#define util_slab_alloc(pool) (pool)->alloc(pool)
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#define util_slab_free(pool, ptr) (pool)->free(pool, ptr)
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#endif
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