src/common/hashtable/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 <stdio.h>
  28
  29 #include "rculfhash.h"
  30
  31 #ifdef DEBUG
  32 #define dbg_printf(fmt, args...)     printf("[debug rculfhash] " fmt, ## args)
  33 #else
  34 #define dbg_printf(fmt, args...)                                \
  35 do {                                                            \
  36         /* do nothing but check printf format */                \
  37         if (0)                                                  \
  38                 printf("[debug rculfhash] " fmt, ## args);      \
  39 } while (0)
  40 #endif
  41
  42 #if (CAA_BITS_PER_LONG == 32)
  43 #define MAX_TABLE_ORDER                 32
  44 #else
  45 #define MAX_TABLE_ORDER                 64
  46 #endif
  47
  48 #define MAX_CHUNK_TABLE                 (1UL << 10)
  49
  50 #ifndef min
  51 #define min(a, b)       ((a) < (b) ? (a) : (b))
  52 #endif
  53
  54 #ifndef max
  55 #define max(a, b)       ((a) > (b) ? (a) : (b))
  56 #endif
  57
  58 struct ht_items_count;
  59
  60 /*
  61  * cds_lfht: Top-level data structure representing a lock-free hash
  62  * table. Defined in the implementation file to make it be an opaque
  63  * cookie to users.
  64  *
  65  * The fields used in fast-paths are placed near the end of the
  66  * structure, because we need to have a variable-sized union to contain
  67  * the mm plugin fields, which are used in the fast path.
  68  */
  69 struct cds_lfht {
  70         /* Initial configuration items */
  71         unsigned long max_nr_buckets;
  72         const struct cds_lfht_mm_type *mm;      /* memory management plugin */
  73         const struct rcu_flavor_struct *flavor; /* RCU flavor */
  74
  75         long count;                     /* global approximate item count */
  76
  77         /*
  78          * We need to put the work threads offline (QSBR) when taking this
  79          * mutex, because we use synchronize_rcu within this mutex critical
  80          * section, which waits on read-side critical sections, and could
  81          * therefore cause grace-period deadlock if we hold off RCU G.P.
  82          * completion.
  83          */
  84         pthread_mutex_t resize_mutex;   /* resize mutex: add/del mutex */
  85         pthread_attr_t *resize_attr;    /* Resize threads attributes */
  86         unsigned int in_progress_resize, in_progress_destroy;
  87         unsigned long resize_target;
  88         int resize_initiated;
  89
  90         /*
  91          * Variables needed for add and remove fast-paths.
  92          */
  93         int flags;
  94         unsigned long min_alloc_buckets_order;
  95         unsigned long min_nr_alloc_buckets;
  96         struct ht_items_count *split_count;     /* split item count */
  97
  98         /*
  99          * Variables needed for the lookup, add and remove fast-paths.
 100          */
 101         unsigned long size;     /* always a power of 2, shared (RCU) */
 102         /*
 103          * bucket_at pointer is kept here to skip the extra level of
 104          * dereference needed to get to "mm" (this is a fast-path).
 105          */
 106         struct cds_lfht_node *(*bucket_at)(struct cds_lfht *ht,
 107                         unsigned long index);
 108         /*
 109          * Dynamic length "tbl_chunk" needs to be at the end of
 110          * cds_lfht.
 111          */
 112         union {
 113                 /*
 114                  * Contains the per order-index-level bucket node table.
 115                  * The size of each bucket node table is half the number
 116                  * of hashes contained in this order (except for order 0).
 117                  * The minimum allocation buckets size parameter allows
 118                  * combining the bucket node arrays of the lowermost
 119                  * levels to improve cache locality for small index orders.
 120                  */
 121                 struct cds_lfht_node *tbl_order[MAX_TABLE_ORDER];
 122
 123                 /*
 124                  * Contains the bucket node chunks. The size of each
 125                  * bucket node chunk is ->min_alloc_size (we avoid to
 126                  * allocate chunks with different size). Chunks improve
 127                  * cache locality for small index orders, and are more
 128                  * friendly with environments where allocation of large
 129                  * contiguous memory areas is challenging due to memory
 130                  * fragmentation concerns or inability to use virtual
 131                  * memory addressing.
 132                  */
 133                 struct cds_lfht_node *tbl_chunk[0];
 134
 135                 /*
 136                  * Memory mapping with room for all possible buckets.
 137                  * Their memory is allocated when needed.
 138                  */
 139                 struct cds_lfht_node *tbl_mmap;
 140         };
 141         /*
 142          * End of variables needed for the lookup, add and remove
 143          * fast-paths.
 144          */
 145 };
 146
 147 extern unsigned int cds_lfht_fls_ulong(unsigned long x);
 148 extern int cds_lfht_get_count_order_ulong(unsigned long x);
 149
 150 #ifdef POISON_FREE
 151 #define poison_free(ptr)                                        \
 152         do {                                                    \
 153                 if (ptr) {                                      \
 154                         memset(ptr, 0x42, sizeof(*(ptr)));      \
 155                         free(ptr);                              \
 156                 }                                               \
 157         } while (0)
 158 #else
 159 #define poison_free(ptr)        free(ptr)
 160 #endif
 161
 162 static inline
 163 struct cds_lfht *__default_alloc_cds_lfht(
 164                 const struct cds_lfht_mm_type *mm,
 165                 unsigned long cds_lfht_size,
 166                 unsigned long min_nr_alloc_buckets,
 167                 unsigned long max_nr_buckets)
 168 {
 169         struct cds_lfht *ht;
 170
 171         ht = calloc(1, cds_lfht_size);
 172         assert(ht);
 173
 174         ht->mm = mm;
 175         ht->bucket_at = mm->bucket_at;
 176         ht->min_nr_alloc_buckets = min_nr_alloc_buckets;
 177         ht->min_alloc_buckets_order =
 178                 cds_lfht_get_count_order_ulong(min_nr_alloc_buckets);
 179         ht->max_nr_buckets = max_nr_buckets;
 180
 181         return ht;
 182 }
 183
 184 #endif /* _URCU_RCULFHASH_INTERNAL_H */