1 // SPDX-FileCopyrightText: 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
2 // SPDX-FileCopyrightText: 2011 Lai Jiangshan <laijs@cn.fujitsu.com>
4 // SPDX-License-Identifier: LGPL-2.1-or-later
6 #ifndef _URCU_RCULFHASH_INTERNAL_H
7 #define _URCU_RCULFHASH_INTERNAL_H
10 * Internal header for Lock-Free RCU Hash Table
13 #include <urcu/assert.h>
14 #include <urcu/rculfhash.h>
18 #include "workqueue.h"
21 #define dbg_printf(fmt, args...) printf("[debug rculfhash] " fmt, ## args)
23 #define dbg_printf(fmt, args...) \
25 /* do nothing but check printf format */ \
27 printf("[debug rculfhash] " fmt, ## args); \
31 #if (CAA_BITS_PER_LONG == 32)
32 #define MAX_TABLE_ORDER 32
34 #define MAX_TABLE_ORDER 64
37 #define MAX_CHUNK_TABLE (1UL << 10)
40 #define min(a, b) ((a) < (b) ? (a) : (b))
44 #define max(a, b) ((a) > (b) ? (a) : (b))
47 struct ht_items_count
;
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
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.
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 */
64 long count
; /* global approximate item count */
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.
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
;
79 struct urcu_work destroy_work
;
82 * Variables needed for add and remove fast-paths.
85 unsigned long min_alloc_buckets_order
;
86 unsigned long min_nr_alloc_buckets
;
87 struct ht_items_count
*split_count
; /* split item count */
90 * Variables needed for the lookup, add and remove fast-paths.
92 unsigned long size
; /* always a power of 2, shared (RCU) */
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).
97 struct cds_lfht_node
*(*bucket_at
)(struct cds_lfht
*ht
,
100 * Dynamic length "tbl_chunk" needs to be at the end of
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.
112 struct cds_lfht_node
*tbl_order
[MAX_TABLE_ORDER
];
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
124 struct cds_lfht_node
*tbl_chunk
[0];
127 * Memory mapping with room for all possible buckets.
128 * Their memory is allocated when needed.
130 struct cds_lfht_node
*tbl_mmap
;
133 * End of variables needed for the lookup, add and remove
138 extern unsigned int cds_lfht_fls_ulong(unsigned long x
);
139 extern int cds_lfht_get_count_order_ulong(unsigned long x
);
142 #define poison_free(ptr) \
145 memset(ptr, 0x42, sizeof(*(ptr))); \
150 #define poison_free(ptr) free(ptr)
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
)
162 ht
= calloc(1, cds_lfht_size
);
163 urcu_posix_assert(ht
);
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
;
175 #endif /* _URCU_RCULFHASH_INTERNAL_H */