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