1 #ifndef _URCU_RCULFHASH_INTERNAL_H
2 #define _URCU_RCULFHASH_INTERNAL_H
5 * urcu/rculfhash-internal.h
7 * Internal header for Lock-Free RCU Hash Table
9 * Copyright 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
10 * Copyright 2011 - Lai Jiangshan <laijs@cn.fujitsu.com>
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.
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.
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
27 #include <urcu/assert.h>
28 #include <urcu/rculfhash.h>
33 #define dbg_printf(fmt, args...) printf("[debug rculfhash] " fmt, ## args)
35 #define dbg_printf(fmt, args...) \
37 /* do nothing but check printf format */ \
39 printf("[debug rculfhash] " fmt, ## args); \
43 #if (CAA_BITS_PER_LONG == 32)
44 #define MAX_TABLE_ORDER 32
46 #define MAX_TABLE_ORDER 64
49 #define MAX_CHUNK_TABLE (1UL << 10)
52 #define min(a, b) ((a) < (b) ? (a) : (b))
56 #define max(a, b) ((a) > (b) ? (a) : (b))
59 struct ht_items_count
;
62 * cds_lfht: Top-level data structure representing a lock-free hash
63 * table. Defined in the implementation file to make it be an opaque
66 * The fields used in fast-paths are placed near the end of the
67 * structure, because we need to have a variable-sized union to contain
68 * the mm plugin fields, which are used in the fast path.
71 /* Initial configuration items */
72 unsigned long max_nr_buckets
;
73 const struct cds_lfht_mm_type
*mm
; /* memory management plugin */
74 const struct rcu_flavor_struct
*flavor
; /* RCU flavor */
76 long count
; /* global approximate item count */
79 * We need to put the work threads offline (QSBR) when taking this
80 * mutex, because we use synchronize_rcu within this mutex critical
81 * section, which waits on read-side critical sections, and could
82 * therefore cause grace-period deadlock if we hold off RCU G.P.
85 pthread_mutex_t resize_mutex
; /* resize mutex: add/del mutex */
86 pthread_attr_t
*resize_attr
; /* Resize threads attributes */
87 unsigned int in_progress_destroy
;
88 unsigned long resize_target
;
92 * Variables needed for add and remove fast-paths.
95 unsigned long min_alloc_buckets_order
;
96 unsigned long min_nr_alloc_buckets
;
97 struct ht_items_count
*split_count
; /* split item count */
100 * Variables needed for the lookup, add and remove fast-paths.
102 unsigned long size
; /* always a power of 2, shared (RCU) */
104 * bucket_at pointer is kept here to skip the extra level of
105 * dereference needed to get to "mm" (this is a fast-path).
107 struct cds_lfht_node
*(*bucket_at
)(struct cds_lfht
*ht
,
108 unsigned long index
);
110 * Dynamic length "tbl_chunk" needs to be at the end of
115 * Contains the per order-index-level bucket node table.
116 * The size of each bucket node table is half the number
117 * of hashes contained in this order (except for order 0).
118 * The minimum allocation buckets size parameter allows
119 * combining the bucket node arrays of the lowermost
120 * levels to improve cache locality for small index orders.
122 struct cds_lfht_node
*tbl_order
[MAX_TABLE_ORDER
];
125 * Contains the bucket node chunks. The size of each
126 * bucket node chunk is ->min_alloc_size (we avoid to
127 * allocate chunks with different size). Chunks improve
128 * cache locality for small index orders, and are more
129 * friendly with environments where allocation of large
130 * contiguous memory areas is challenging due to memory
131 * fragmentation concerns or inability to use virtual
134 struct cds_lfht_node
*tbl_chunk
[0];
137 * Memory mapping with room for all possible buckets.
138 * Their memory is allocated when needed.
140 struct cds_lfht_node
*tbl_mmap
;
143 * End of variables needed for the lookup, add and remove
148 extern unsigned int cds_lfht_fls_ulong(unsigned long x
);
149 extern int cds_lfht_get_count_order_ulong(unsigned long x
);
152 #define poison_free(ptr) \
155 memset(ptr, 0x42, sizeof(*(ptr))); \
160 #define poison_free(ptr) free(ptr)
164 struct cds_lfht
*__default_alloc_cds_lfht(
165 const struct cds_lfht_mm_type
*mm
,
166 unsigned long cds_lfht_size
,
167 unsigned long min_nr_alloc_buckets
,
168 unsigned long max_nr_buckets
)
172 ht
= calloc(1, cds_lfht_size
);
173 urcu_posix_assert(ht
);
176 ht
->bucket_at
= mm
->bucket_at
;
177 ht
->min_nr_alloc_buckets
= min_nr_alloc_buckets
;
178 ht
->min_alloc_buckets_order
=
179 cds_lfht_get_count_order_ulong(min_nr_alloc_buckets
);
180 ht
->max_nr_buckets
= max_nr_buckets
;
185 #endif /* _URCU_RCULFHASH_INTERNAL_H */