1 #ifndef _URCU_RCULFHASH_H
2 #define _URCU_RCULFHASH_H
7 * Userspace RCU library - Lock-Free RCU Hash Table
9 * Copyright 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
11 * This library is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU Lesser General Public
13 * License as published by the Free Software Foundation; either
14 * version 2.1 of the License, or (at your option) any later version.
16 * This library is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * Lesser General Public License for more details.
21 * You should have received a copy of the GNU Lesser General Public
22 * License along with this library; if not, write to the Free Software
23 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
27 #include <urcu-call-rcu.h>
34 * struct rcu_ht_node and struct _rcu_ht_node should be aligned on
35 * 4-bytes boundaries because the two lower bits are used as flags.
39 struct rcu_ht_node
*next
; /* ptr | DUMMY_FLAG | REMOVED_FLAG */
40 unsigned long reverse_hash
;
44 /* cache-hot for iteration */
45 struct _rcu_ht_node p
; /* needs to be first field */
48 /* cache-cold for iteration */
56 * Ensure reader and writer threads are registered as urcu readers.
59 typedef unsigned long (*ht_hash_fct
)(void *key
, size_t length
,
61 typedef unsigned long (*ht_compare_fct
)(void *key1
, size_t key1_len
,
62 void *key2
, size_t key2_len
);
65 * ht_node_init - initialize a hash table node
68 void ht_node_init(struct rcu_ht_node
*node
, void *key
,
72 node
->key_len
= key_len
;
76 * ht_new - allocate a hash table.
78 * init_size must be power of two.
80 struct rcu_ht
*ht_new(ht_hash_fct hash_fct
,
81 ht_compare_fct compare_fct
,
82 unsigned long hash_seed
,
83 unsigned long init_size
,
84 void (*ht_call_rcu
)(struct rcu_head
*head
,
85 void (*func
)(struct rcu_head
*head
)));
88 * ht_destroy - destroy a hash table.
90 int ht_destroy(struct rcu_ht
*ht
);
93 * ht_count_nodes - count the number of nodes in the hash table.
95 * Call with rcu_read_lock held.
97 void ht_count_nodes(struct rcu_ht
*ht
,
99 unsigned long *removed
);
102 * ht_lookup - lookup a node by key.
104 * Returns NULL if not found.
105 * Call with rcu_read_lock held.
107 struct rcu_ht_node
*ht_lookup(struct rcu_ht
*ht
, void *key
, size_t key_len
);
110 * ht_next - get the next item with same key (after a lookup).
112 * Returns NULL if no following node exists with same key.
113 * RCU read-side lock must be held across ht_lookup and ht_next calls, and also
114 * between ht_next calls using the node returned by a previous ht_next.
115 * Call with rcu_read_lock held.
117 struct rcu_ht_node
*ht_next(struct rcu_ht
*ht
, struct rcu_ht_node
*node
);
120 * ht_add - add a node to the hash table.
122 * Call with rcu_read_lock held.
124 void ht_add(struct rcu_ht
*ht
, struct rcu_ht_node
*node
);
127 * ht_add_unique - add a node to hash table, if key is not present.
129 * Returns the node added upon success.
130 * Returns the unique node already present upon failure. If ht_add_unique fails,
131 * the node passed as parameter should be freed by the caller.
132 * Call with rcu_read_lock held.
134 struct rcu_ht_node
*ht_add_unique(struct rcu_ht
*ht
, struct rcu_ht_node
*node
);
137 * ht_remove - remove node from hash table.
139 * Node can be looked up with ht_lookup. RCU read-side lock must be held between
140 * lookup and removal.
141 * Call with rcu_read_lock held.
143 int ht_remove(struct rcu_ht
*ht
, struct rcu_ht_node
*node
);
146 * ht_resize - Force a hash table resize
147 * @growth: growth order (current size is multiplied by 2^growth)
149 * Currently, only expand operation is supported (growth >= 0).
151 void ht_resize(struct rcu_ht
*ht
, int growth
);
157 #endif /* _URCU_RCULFHASH_H */