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/assert.h>
  28 #include <urcu/rculfhash.h>
  29 #include <stdio.h>
  30 #include <stdlib.h>
  31
  32 #include "workqueue.h"
  33
  34 #ifdef DEBUG
  35 #define dbg_printf(fmt, args...)     printf("[debug rculfhash] " fmt, ## args)
  36 #else
  37 #define dbg_printf(fmt, args...)                                \
  38 do {                                                            \
  39         /* do nothing but check printf format */                \
  40         if (0)                                                  \
  41                 printf("[debug rculfhash] " fmt, ## args);      \
  42 } while (0)
  43 #endif
  44
  45 #if (CAA_BITS_PER_LONG == 32)
  46 #define MAX_TABLE_ORDER                 32
  47 #else
  48 #define MAX_TABLE_ORDER                 64
  49 #endif
  50
  51 #define MAX_CHUNK_TABLE                 (1UL << 10)
  52
  53 #ifndef min
  54 #define min(a, b)       ((a) < (b) ? (a) : (b))
  55 #endif
  56
  57 #ifndef max
  58 #define max(a, b)       ((a) > (b) ? (a) : (b))
  59 #endif
  60
  61 struct ht_items_count;
  62
  63 /*
  64  * cds_lfht: Top-level data structure representing a lock-free hash
  65  * table. Defined in the implementation file to make it be an opaque
  66  * cookie to users.
  67  *
  68  * The fields used in fast-paths are placed near the end of the
  69  * structure, because we need to have a variable-sized union to contain
  70  * the mm plugin fields, which are used in the fast path.
  71  */
  72 struct cds_lfht {
  73         /* Initial configuration items */
  74         unsigned long max_nr_buckets;
  75         const struct cds_lfht_mm_type *mm;      /* memory management plugin */
  76         const struct rcu_flavor_struct *flavor; /* RCU flavor */
  77
  78         long count;                     /* global approximate item count */
  79
  80         /*
  81          * We need to put the work threads offline (QSBR) when taking this
  82          * mutex, because we use synchronize_rcu within this mutex critical
  83          * section, which waits on read-side critical sections, and could
  84          * therefore cause grace-period deadlock if we hold off RCU G.P.
  85          * completion.
  86          */
  87         pthread_mutex_t resize_mutex;           /* resize mutex: add/del mutex */
  88         pthread_attr_t *caller_resize_attr;     /* resize threads attributes from lfht_new caller */
  89         pthread_attr_t resize_attr;
  90         unsigned int in_progress_destroy;
  91         unsigned long resize_target;
  92         int resize_initiated;
  93         struct urcu_work destroy_work;
  94
  95         /*
  96          * Variables needed for add and remove fast-paths.
  97          */
  98         int flags;
  99         unsigned long min_alloc_buckets_order;
 100         unsigned long min_nr_alloc_buckets;
 101         struct ht_items_count *split_count;     /* split item count */
 102
 103         /*
 104          * Variables needed for the lookup, add and remove fast-paths.
 105          */
 106         unsigned long size;     /* always a power of 2, shared (RCU) */
 107         /*
 108          * bucket_at pointer is kept here to skip the extra level of
 109          * dereference needed to get to "mm" (this is a fast-path).
 110          */
 111         struct cds_lfht_node *(*bucket_at)(struct cds_lfht *ht,
 112                         unsigned long index);
 113         /*
 114          * Dynamic length "tbl_chunk" needs to be at the end of
 115          * cds_lfht.
 116          */
 117         union {
 118                 /*
 119                  * Contains the per order-index-level bucket node table.
 120                  * The size of each bucket node table is half the number
 121                  * of hashes contained in this order (except for order 0).
 122                  * The minimum allocation buckets size parameter allows
 123                  * combining the bucket node arrays of the lowermost
 124                  * levels to improve cache locality for small index orders.
 125                  */
 126                 struct cds_lfht_node *tbl_order[MAX_TABLE_ORDER];
 127
 128                 /*
 129                  * Contains the bucket node chunks. The size of each
 130                  * bucket node chunk is ->min_alloc_size (we avoid to
 131                  * allocate chunks with different size). Chunks improve
 132                  * cache locality for small index orders, and are more
 133                  * friendly with environments where allocation of large
 134                  * contiguous memory areas is challenging due to memory
 135                  * fragmentation concerns or inability to use virtual
 136                  * memory addressing.
 137                  */
 138                 struct cds_lfht_node *tbl_chunk[0];
 139
 140                 /*
 141                  * Memory mapping with room for all possible buckets.
 142                  * Their memory is allocated when needed.
 143                  */
 144                 struct cds_lfht_node *tbl_mmap;
 145         };
 146         /*
 147          * End of variables needed for the lookup, add and remove
 148          * fast-paths.
 149          */
 150 };
 151
 152 extern unsigned int cds_lfht_fls_ulong(unsigned long x);
 153 extern int cds_lfht_get_count_order_ulong(unsigned long x);
 154
 155 #ifdef POISON_FREE
 156 #define poison_free(ptr)                                        \
 157         do {                                                    \
 158                 if (ptr) {                                      \
 159                         memset(ptr, 0x42, sizeof(*(ptr)));      \
 160                         free(ptr);                              \
 161                 }                                               \
 162         } while (0)
 163 #else
 164 #define poison_free(ptr)        free(ptr)
 165 #endif
 166
 167 static inline
 168 struct cds_lfht *__default_alloc_cds_lfht(
 169                 const struct cds_lfht_mm_type *mm,
 170                 unsigned long cds_lfht_size,
 171                 unsigned long min_nr_alloc_buckets,
 172                 unsigned long max_nr_buckets)
 173 {
 174         struct cds_lfht *ht;
 175
 176         ht = calloc(1, cds_lfht_size);
 177         urcu_posix_assert(ht);
 178
 179         ht->mm = mm;
 180         ht->bucket_at = mm->bucket_at;
 181         ht->min_nr_alloc_buckets = min_nr_alloc_buckets;
 182         ht->min_alloc_buckets_order =
 183                 cds_lfht_get_count_order_ulong(min_nr_alloc_buckets);
 184         ht->max_nr_buckets = max_nr_buckets;
 185
 186         return ht;
 187 }
 188
 189 #endif /* _URCU_RCULFHASH_INTERNAL_H */