src/rculfhash-internal.h

   1 // SPDX-FileCopyrightText: 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   2 // SPDX-FileCopyrightText: 2011 Lai Jiangshan <laijs@cn.fujitsu.com>
   3 //
   4 // SPDX-License-Identifier: LGPL-2.1-or-later
   5
   6 #ifndef _URCU_RCULFHASH_INTERNAL_H
   7 #define _URCU_RCULFHASH_INTERNAL_H
   8
   9 /*
  10  * Internal header for Lock-Free RCU Hash Table
  11  */
  12
  13 #include <urcu/assert.h>
  14 #include <urcu/rculfhash.h>
  15 #include <stdio.h>
  16 #include <stdlib.h>
  17
  18 #include "workqueue.h"
  19
  20 #ifdef DEBUG
  21 #define dbg_printf(fmt, args...)     printf("[debug rculfhash] " fmt, ## args)
  22 #else
  23 #define dbg_printf(fmt, args...)                                \
  24 do {                                                            \
  25         /* do nothing but check printf format */                \
  26         if (0)                                                  \
  27                 printf("[debug rculfhash] " fmt, ## args);      \
  28 } while (0)
  29 #endif
  30
  31 #if (CAA_BITS_PER_LONG == 32)
  32 #define MAX_TABLE_ORDER                 32
  33 #else
  34 #define MAX_TABLE_ORDER                 64
  35 #endif
  36
  37 #define MAX_CHUNK_TABLE                 (1UL << 10)
  38
  39 #ifndef min
  40 #define min(a, b)       ((a) < (b) ? (a) : (b))
  41 #endif
  42
  43 #ifndef max
  44 #define max(a, b)       ((a) > (b) ? (a) : (b))
  45 #endif
  46
  47 struct ht_items_count;
  48
  49 /*
  50  * cds_lfht: Top-level data structure representing a lock-free hash
  51  * table. Defined in the implementation file to make it be an opaque
  52  * cookie to users.
  53  *
  54  * The fields used in fast-paths are placed near the end of the
  55  * structure, because we need to have a variable-sized union to contain
  56  * the mm plugin fields, which are used in the fast path.
  57  */
  58 struct cds_lfht {
  59         /* Initial configuration items */
  60         unsigned long max_nr_buckets;
  61         const struct cds_lfht_mm_type *mm;      /* memory management plugin */
  62         const struct rcu_flavor_struct *flavor; /* RCU flavor */
  63
  64         long count;                     /* global approximate item count */
  65
  66         /*
  67          * We need to put the work threads offline (QSBR) when taking this
  68          * mutex, because we use synchronize_rcu within this mutex critical
  69          * section, which waits on read-side critical sections, and could
  70          * therefore cause grace-period deadlock if we hold off RCU G.P.
  71          * completion.
  72          */
  73         pthread_mutex_t resize_mutex;           /* resize mutex: add/del mutex */
  74         pthread_attr_t *caller_resize_attr;     /* resize threads attributes from lfht_new caller */
  75         pthread_attr_t resize_attr;
  76         unsigned int in_progress_destroy;
  77         unsigned long resize_target;
  78         int resize_initiated;
  79         struct urcu_work destroy_work;
  80
  81         /*
  82          * Variables needed for add and remove fast-paths.
  83          */
  84         int flags;
  85         unsigned long min_alloc_buckets_order;
  86         unsigned long min_nr_alloc_buckets;
  87         struct ht_items_count *split_count;     /* split item count */
  88
  89         /*
  90          * Variables needed for the lookup, add and remove fast-paths.
  91          */
  92         unsigned long size;     /* always a power of 2, shared (RCU) */
  93         /*
  94          * bucket_at pointer is kept here to skip the extra level of
  95          * dereference needed to get to "mm" (this is a fast-path).
  96          */
  97         struct cds_lfht_node *(*bucket_at)(struct cds_lfht *ht,
  98                         unsigned long index);
  99         /*
 100          * Dynamic length "tbl_chunk" needs to be at the end of
 101          * cds_lfht.
 102          */
 103         union {
 104                 /*
 105                  * Contains the per order-index-level bucket node table.
 106                  * The size of each bucket node table is half the number
 107                  * of hashes contained in this order (except for order 0).
 108                  * The minimum allocation buckets size parameter allows
 109                  * combining the bucket node arrays of the lowermost
 110                  * levels to improve cache locality for small index orders.
 111                  */
 112                 struct cds_lfht_node *tbl_order[MAX_TABLE_ORDER];
 113
 114                 /*
 115                  * Contains the bucket node chunks. The size of each
 116                  * bucket node chunk is ->min_alloc_size (we avoid to
 117                  * allocate chunks with different size). Chunks improve
 118                  * cache locality for small index orders, and are more
 119                  * friendly with environments where allocation of large
 120                  * contiguous memory areas is challenging due to memory
 121                  * fragmentation concerns or inability to use virtual
 122                  * memory addressing.
 123                  */
 124                 struct cds_lfht_node *tbl_chunk[0];
 125
 126                 /*
 127                  * Memory mapping with room for all possible buckets.
 128                  * Their memory is allocated when needed.
 129                  */
 130                 struct cds_lfht_node *tbl_mmap;
 131         };
 132         /*
 133          * End of variables needed for the lookup, add and remove
 134          * fast-paths.
 135          */
 136 };
 137
 138 extern unsigned int cds_lfht_fls_ulong(unsigned long x);
 139 extern int cds_lfht_get_count_order_ulong(unsigned long x);
 140
 141 #ifdef POISON_FREE
 142 #define poison_free(ptr)                                        \
 143         do {                                                    \
 144                 if (ptr) {                                      \
 145                         memset(ptr, 0x42, sizeof(*(ptr)));      \
 146                         free(ptr);                              \
 147                 }                                               \
 148         } while (0)
 149 #else
 150 #define poison_free(ptr)        free(ptr)
 151 #endif
 152
 153 static inline
 154 struct cds_lfht *__default_alloc_cds_lfht(
 155                 const struct cds_lfht_mm_type *mm,
 156                 unsigned long cds_lfht_size,
 157                 unsigned long min_nr_alloc_buckets,
 158                 unsigned long max_nr_buckets)
 159 {
 160         struct cds_lfht *ht;
 161
 162         ht = calloc(1, cds_lfht_size);
 163         urcu_posix_assert(ht);
 164
 165         ht->mm = mm;
 166         ht->bucket_at = mm->bucket_at;
 167         ht->min_nr_alloc_buckets = min_nr_alloc_buckets;
 168         ht->min_alloc_buckets_order =
 169                 cds_lfht_get_count_order_ulong(min_nr_alloc_buckets);
 170         ht->max_nr_buckets = max_nr_buckets;
 171
 172         return ht;
 173 }
 174
 175 #endif /* _URCU_RCULFHASH_INTERNAL_H */