workbench/libs/mesa/src/gallium/auxiliary/util/u_slab.h

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