src/common/mempool.h

   1 /* Copyright (c) 2007-2010, The Tor Project, Inc. */
   2 /* See LICENSE for licensing information */
   3
   4 /**
   5  * \file mempool.h
   6  * \brief Headers for mempool.c
   7  **/
   8
   9 #ifndef _TOR_MEMPOOL_H
  10 #define _TOR_MEMPOOL_H
  11
  12 /** A memory pool is a context in which a large number of fixed-sized
  13 * objects can be allocated efficiently.  See mempool.c for implementation
  14 * details. */
  15 typedef struct mp_pool_t mp_pool_t;
  16
  17 void *mp_pool_get(mp_pool_t *pool);
  18 void mp_pool_release(void *item);
  19 mp_pool_t *mp_pool_new(size_t item_size, size_t chunk_capacity);
  20 void mp_pool_clean(mp_pool_t *pool, int n_to_keep, int keep_recently_used);
  21 void mp_pool_destroy(mp_pool_t *pool);
  22 void mp_pool_assert_ok(mp_pool_t *pool);
  23 void mp_pool_log_status(mp_pool_t *pool, int severity);
  24
  25 #define MEMPOOL_STATS
  26
  27 #ifdef MEMPOOL_PRIVATE
  28 /* These declarations are only used by mempool.c and test.c */
  29
  30 struct mp_pool_t {
  31   /** Doubly-linked list of chunks in which no items have been allocated.
  32    * The front of the list is the most recently emptied chunk. */
  33   struct mp_chunk_t *empty_chunks;
  34   /** Doubly-linked list of chunks in which some items have been allocated,
  35    * but which are not yet full. The front of the list is the chunk that has
  36    * most recently been modified. */
  37   struct mp_chunk_t *used_chunks;
  38   /** Doubly-linked list of chunks in which no more items can be allocated.
  39    * The front of the list is the chunk that has most recently become full. */
  40   struct mp_chunk_t *full_chunks;
  41   /** Length of <b>empty_chunks</b>. */
  42   int n_empty_chunks;
  43   /** Lowest value of <b>empty_chunks</b> since last call to
  44    * mp_pool_clean(-1). */
  45   int min_empty_chunks;
  46   /** Size of each chunk (in items). */
  47   int new_chunk_capacity;
  48   /** Size to allocate for each item, including overhead and alignment
  49    * padding. */
  50   size_t item_alloc_size;
  51 #ifdef MEMPOOL_STATS
  52   /** Total number of items allocated ever. */
  53   uint64_t total_items_allocated;
  54   /** Total number of chunks allocated ever. */
  55   uint64_t total_chunks_allocated;
  56   /** Total number of chunks freed ever. */
  57   uint64_t total_chunks_freed;
  58 #endif
  59 };
  60 #endif
  61
  62 #endif
  63