src/rculfhash-internal.h

   1 #ifndef _URCU_RCULFHASH_INTERNAL_H
   2 #define _URCU_RCULFHASH_INTERNAL_H
   3
   4 /*
   5  * urcu/rculfhash-internal.h
   6  *
   7  * Internal header for Lock-Free RCU Hash Table
   8  *
   9  * Copyright 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  10  * Copyright 2011 - Lai Jiangshan <laijs@cn.fujitsu.com>
  11  *
  12  * This library is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU Lesser General Public
  14  * License as published by the Free Software Foundation; either
  15  * version 2.1 of the License, or (at your option) any later version.
  16  *
  17  * This library is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  * Lesser General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Lesser General Public
  23  * License along with this library; if not, write to the Free Software
  24  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  25  */
  26
  27 #include <urcu/rculfhash.h>
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <assert.h>
  31
  32 #ifdef DEBUG
  33 #define dbg_printf(fmt, args...)     printf("[debug rculfhash] " fmt, ## args)
  34 #else
  35 #define dbg_printf(fmt, args...)                                \
  36 do {                                                            \
  37         /* do nothing but check printf format */                \
  38         if (0)                                                  \
  39                 printf("[debug rculfhash] " fmt, ## args);      \
  40 } while (0)
  41 #endif
  42
  43 #if (CAA_BITS_PER_LONG == 32)
  44 #define MAX_TABLE_ORDER                 32
  45 #else
  46 #define MAX_TABLE_ORDER                 64
  47 #endif
  48
  49 #define MAX_CHUNK_TABLE                 (1UL << 10)
  50
  51 #ifndef min
  52 #define min(a, b)       ((a) < (b) ? (a) : (b))
  53 #endif
  54
  55 #ifndef max
  56 #define max(a, b)       ((a) > (b) ? (a) : (b))
  57 #endif
  58
  59 struct ht_items_count;
  60
  61 /*
  62  * cds_lfht: Top-level data structure representing a lock-free hash
  63  * table. Defined in the implementation file to make it be an opaque
  64  * cookie to users.
  65  *
  66  * The fields used in fast-paths are placed near the end of the
  67  * structure, because we need to have a variable-sized union to contain
  68  * the mm plugin fields, which are used in the fast path.
  69  */
  70 struct cds_lfht {
  71         /* Initial configuration items */
  72         unsigned long max_nr_buckets;
  73         const struct cds_lfht_mm_type *mm;      /* memory management plugin */
  74         const struct rcu_flavor_struct *flavor; /* RCU flavor */
  75
  76         long count;                     /* global approximate item count */
  77
  78         /*
  79          * We need to put the work threads offline (QSBR) when taking this
  80          * mutex, because we use synchronize_rcu within this mutex critical
  81          * section, which waits on read-side critical sections, and could
  82          * therefore cause grace-period deadlock if we hold off RCU G.P.
  83          * completion.
  84          */
  85         pthread_mutex_t resize_mutex;   /* resize mutex: add/del mutex */
  86         pthread_attr_t *resize_attr;    /* Resize threads attributes */
  87         unsigned int in_progress_destroy;
  88         unsigned long resize_target;
  89         int resize_initiated;
  90
  91         /*
  92          * Variables needed for add and remove fast-paths.
  93          */
  94         int flags;
  95         unsigned long min_alloc_buckets_order;
  96         unsigned long min_nr_alloc_buckets;
  97         struct ht_items_count *split_count;     /* split item count */
  98
  99         /*
 100          * Variables needed for the lookup, add and remove fast-paths.
 101          */
 102         unsigned long size;     /* always a power of 2, shared (RCU) */
 103         /*
 104          * bucket_at pointer is kept here to skip the extra level of
 105          * dereference needed to get to "mm" (this is a fast-path).
 106          */
 107         struct cds_lfht_node *(*bucket_at)(struct cds_lfht *ht,
 108                         unsigned long index);
 109         /*
 110          * Dynamic length "tbl_chunk" needs to be at the end of
 111          * cds_lfht.
 112          */
 113         union {
 114                 /*
 115                  * Contains the per order-index-level bucket node table.
 116                  * The size of each bucket node table is half the number
 117                  * of hashes contained in this order (except for order 0).
 118                  * The minimum allocation buckets size parameter allows
 119                  * combining the bucket node arrays of the lowermost
 120                  * levels to improve cache locality for small index orders.
 121                  */
 122                 struct cds_lfht_node *tbl_order[MAX_TABLE_ORDER];
 123
 124                 /*
 125                  * Contains the bucket node chunks. The size of each
 126                  * bucket node chunk is ->min_alloc_size (we avoid to
 127                  * allocate chunks with different size). Chunks improve
 128                  * cache locality for small index orders, and are more
 129                  * friendly with environments where allocation of large
 130                  * contiguous memory areas is challenging due to memory
 131                  * fragmentation concerns or inability to use virtual
 132                  * memory addressing.
 133                  */
 134                 struct cds_lfht_node *tbl_chunk[0];
 135
 136                 /*
 137                  * Memory mapping with room for all possible buckets.
 138                  * Their memory is allocated when needed.
 139                  */
 140                 struct cds_lfht_node *tbl_mmap;
 141         };
 142         /*
 143          * End of variables needed for the lookup, add and remove
 144          * fast-paths.
 145          */
 146 };
 147
 148 extern unsigned int cds_lfht_fls_ulong(unsigned long x);
 149 extern int cds_lfht_get_count_order_ulong(unsigned long x);
 150
 151 #ifdef POISON_FREE
 152 #define poison_free(ptr)                                        \
 153         do {                                                    \
 154                 if (ptr) {                                      \
 155                         memset(ptr, 0x42, sizeof(*(ptr)));      \
 156                         free(ptr);                              \
 157                 }                                               \
 158         } while (0)
 159 #else
 160 #define poison_free(ptr)        free(ptr)
 161 #endif
 162
 163 static inline
 164 struct cds_lfht *__default_alloc_cds_lfht(
 165                 const struct cds_lfht_mm_type *mm,
 166                 unsigned long cds_lfht_size,
 167                 unsigned long min_nr_alloc_buckets,
 168                 unsigned long max_nr_buckets)
 169 {
 170         struct cds_lfht *ht;
 171
 172         ht = calloc(1, cds_lfht_size);
 173         assert(ht);
 174
 175         ht->mm = mm;
 176         ht->bucket_at = mm->bucket_at;
 177         ht->min_nr_alloc_buckets = min_nr_alloc_buckets;
 178         ht->min_alloc_buckets_order =
 179                 cds_lfht_get_count_order_ulong(min_nr_alloc_buckets);
 180         ht->max_nr_buckets = max_nr_buckets;
 181
 182         return ht;
 183 }
 184
 185 #endif /* _URCU_RCULFHASH_INTERNAL_H */