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/rculfhash.h>
30 #define dbg_printf(fmt, args...) printf("[debug rculfhash] " fmt, ## args)
32 #define dbg_printf(fmt, args...)
35 #if (CAA_BITS_PER_LONG == 32)
36 #define MAX_TABLE_ORDER 32
38 #define MAX_TABLE_ORDER 64
41 #define MAX_CHUNK_TABLE (1UL << 10)
44 #define min(a, b) ((a) < (b) ? (a) : (b))
48 #define max(a, b) ((a) > (b) ? (a) : (b))
51 struct ht_items_count
;
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
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.
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 */
68 long count
; /* global approximate item count */
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.
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
;
84 * Variables needed for add and remove fast-paths.
87 unsigned long min_alloc_buckets_order
;
88 unsigned long min_nr_alloc_buckets
;
89 struct ht_items_count
*split_count
; /* split item count */
92 * Variables needed for the lookup, add and remove fast-paths.
94 unsigned long size
; /* always a power of 2, shared (RCU) */
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).
99 struct cds_lfht_node
*(*bucket_at
)(struct cds_lfht
*ht
,
100 unsigned long index
);
102 * Dynamic length "tbl_chunk" needs to be at the end of
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.
114 struct cds_lfht_node
*tbl_order
[MAX_TABLE_ORDER
];
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
126 struct cds_lfht_node
*tbl_chunk
[0];
129 * Memory mapping with room for all possible buckets.
130 * Their memory is allocated when needed.
132 struct cds_lfht_node
*tbl_mmap
;
135 * End of variables needed for the lookup, add and remove
140 extern unsigned int fls_ulong(unsigned long x
);
141 extern int get_count_order_ulong(unsigned long x
);
144 #define poison_free(ptr) \
147 memset(ptr, 0x42, sizeof(*(ptr))); \
152 #define poison_free(ptr) free(ptr)
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
)
164 ht
= calloc(1, cds_lfht_size
);
168 ht
->bucket_at
= mm
->bucket_at
;
169 ht
->min_nr_alloc_buckets
= min_nr_alloc_buckets
;
170 ht
->min_alloc_buckets_order
=
171 get_count_order_ulong(min_nr_alloc_buckets
);
172 ht
->max_nr_buckets
= max_nr_buckets
;
177 #endif /* _URCU_RCULFHASH_INTERNAL_H */