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
  29 #ifdef DEBUG
  30 #define dbg_printf(fmt, args...)     printf("[debug rculfhash] " fmt, ## args)
  31 #else
  32 #define dbg_printf(fmt, args...)
  33 #endif
  34
  35 #if (CAA_BITS_PER_LONG == 32)
  36 #define MAX_TABLE_ORDER                 32
  37 #else
  38 #define MAX_TABLE_ORDER                 64
  39 #endif
  40
  41 #define MAX_CHUNK_TABLE                 (1UL << 10)
  42
  43 #ifndef min
  44 #define min(a, b)       ((a) < (b) ? (a) : (b))
  45 #endif
  46
  47 #ifndef max
  48 #define max(a, b)       ((a) > (b) ? (a) : (b))
  49 #endif
  50
  51 struct ht_items_count;
  52
  53 /*
  54  * cds_lfht: Top-level data structure representing a lock-free hash
  55  * table. Defined in the implementation file to make it be an opaque
  56  * cookie to users.
  57  *
  58  * The fields used in fast-paths are placed near the end of the
  59  * structure, because we need to have a variable-sized union to contain
  60  * the mm plugin fields, which are used in the fast path.
  61  */
  62 struct cds_lfht {
  63         /* Initial configuration items */
  64         unsigned long max_nr_buckets;
  65         const struct cds_lfht_mm_type *mm;      /* memory management plugin */
  66         const struct rcu_flavor_struct *flavor; /* RCU flavor */
  67
  68         long count;                     /* global approximate item count */
  69
  70         /*
  71          * We need to put the work threads offline (QSBR) when taking this
  72          * mutex, because we use synchronize_rcu within this mutex critical
  73          * section, which waits on read-side critical sections, and could
  74          * therefore cause grace-period deadlock if we hold off RCU G.P.
  75          * completion.
  76          */
  77         pthread_mutex_t resize_mutex;   /* resize mutex: add/del mutex */
  78         pthread_attr_t *resize_attr;    /* Resize threads attributes */
  79         unsigned int in_progress_resize, in_progress_destroy;
  80         unsigned long resize_target;
  81         int resize_initiated;
  82
  83         /*
  84          * Variables needed for add and remove fast-paths.
  85          */
  86         int flags;
  87         unsigned long min_alloc_buckets_order;
  88         unsigned long min_nr_alloc_buckets;
  89         struct ht_items_count *split_count;     /* split item count */
  90
  91         /*
  92          * Variables needed for the lookup, add and remove fast-paths.
  93          */
  94         unsigned long size;     /* always a power of 2, shared (RCU) */
  95         /*
  96          * bucket_at pointer is kept here to skip the extra level of
  97          * dereference needed to get to "mm" (this is a fast-path).
  98          */
  99         struct cds_lfht_node *(*bucket_at)(struct cds_lfht *ht,
 100                         unsigned long index);
 101         /*
 102          * Dynamic length "tbl_chunk" needs to be at the end of
 103          * cds_lfht.
 104          */
 105         union {
 106                 /*
 107                  * Contains the per order-index-level bucket node table.
 108                  * The size of each bucket node table is half the number
 109                  * of hashes contained in this order (except for order 0).
 110                  * The minimum allocation buckets size parameter allows
 111                  * combining the bucket node arrays of the lowermost
 112                  * levels to improve cache locality for small index orders.
 113                  */
 114                 struct cds_lfht_node *tbl_order[MAX_TABLE_ORDER];
 115
 116                 /*
 117                  * Contains the bucket node chunks. The size of each
 118                  * bucket node chunk is ->min_alloc_size (we avoid to
 119                  * allocate chunks with different size). Chunks improve
 120                  * cache locality for small index orders, and are more
 121                  * friendly with environments where allocation of large
 122                  * contiguous memory areas is challenging due to memory
 123                  * fragmentation concerns or inability to use virtual
 124                  * memory addressing.
 125                  */
 126                 struct cds_lfht_node *tbl_chunk[0];
 127
 128                 /*
 129                  * Memory mapping with room for all possible buckets.
 130                  * Their memory is allocated when needed.
 131                  */
 132                 struct cds_lfht_node *tbl_mmap;
 133         };
 134         /*
 135          * End of variables needed for the lookup, add and remove
 136          * fast-paths.
 137          */
 138 };
 139
 140 extern unsigned int cds_lfht_fls_ulong(unsigned long x);
 141 extern int cds_lfht_get_count_order_ulong(unsigned long x);
 142
 143 #ifdef POISON_FREE
 144 #define poison_free(ptr)                                        \
 145         do {                                                    \
 146                 if (ptr) {                                      \
 147                         memset(ptr, 0x42, sizeof(*(ptr)));      \
 148                         free(ptr);                              \
 149                 }                                               \
 150         } while (0)
 151 #else
 152 #define poison_free(ptr)        free(ptr)
 153 #endif
 154
 155 static inline
 156 struct cds_lfht *__default_alloc_cds_lfht(
 157                 const struct cds_lfht_mm_type *mm,
 158                 unsigned long cds_lfht_size,
 159                 unsigned long min_nr_alloc_buckets,
 160                 unsigned long max_nr_buckets)
 161 {
 162         struct cds_lfht *ht;
 163
 164         ht = calloc(1, cds_lfht_size);
 165         assert(ht);
 166
 167         ht->mm = mm;
 168         ht->bucket_at = mm->bucket_at;
 169         ht->min_nr_alloc_buckets = min_nr_alloc_buckets;
 170         ht->min_alloc_buckets_order =
 171                 cds_lfht_get_count_order_ulong(min_nr_alloc_buckets);
 172         ht->max_nr_buckets = max_nr_buckets;
 173
 174         return ht;
 175 }
 176
 177 #endif /* _URCU_RCULFHASH_INTERNAL_H */