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a42cc659 MD |
1 | #ifndef _URCU_RCULFHASH_H |
2 | #define _URCU_RCULFHASH_H | |
ab7d5fc6 | 3 | |
f0c29ed7 MD |
4 | /* |
5 | * urcu/rculfhash.h | |
6 | * | |
7 | * Userspace RCU library - Lock-Free RCU Hash Table | |
8 | * | |
9 | * Copyright 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
10 | * | |
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. | |
15 | * | |
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. | |
20 | * | |
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 | |
cf77d1fa MD |
24 | * |
25 | * Include this file _after_ including your URCU flavor. | |
f0c29ed7 MD |
26 | */ |
27 | ||
674f7a69 | 28 | #include <stdint.h> |
abc490a1 MD |
29 | #include <urcu-call-rcu.h> |
30 | ||
01389791 MD |
31 | #ifdef __cplusplus |
32 | extern "C" { | |
33 | #endif | |
34 | ||
7f61a77f | 35 | /* |
14044b37 | 36 | * struct cds_lfht_node and struct _cds_lfht_node should be aligned on |
b198f0fd | 37 | * 4-bytes boundaries because the two lower bits are used as flags. |
7f61a77f MD |
38 | */ |
39 | ||
7f52427b MD |
40 | /* |
41 | * _cds_lfht_node: Contains the internal pointers and reverse-hash | |
42 | * value required for lookup and traversal of the hash table. | |
43 | */ | |
14044b37 | 44 | struct _cds_lfht_node { |
b198f0fd | 45 | struct cds_lfht_node *next; /* ptr | DUMMY_FLAG | REMOVED_FLAG */ |
abc490a1 | 46 | unsigned long reverse_hash; |
58ca0741 | 47 | } __attribute__((aligned(4))); |
cc4fcb10 | 48 | |
ae62aa6a | 49 | /* |
7f52427b MD |
50 | * cds_lfht_node: Contains the full key and length required to check for |
51 | * an actual match, and also contains an rcu_head structure that is used | |
52 | * by RCU to track a node through a given RCU grace period. There is an | |
53 | * instance of _cds_lfht_node enclosed as a field within each | |
54 | * _cds_lfht_node structure. | |
55 | * | |
ae62aa6a MD |
56 | * struct cds_lfht_node can be embedded into a structure (as a field). |
57 | * caa_container_of() can be used to get the structure from the struct | |
58 | * cds_lfht_node after a lookup. | |
59 | */ | |
14044b37 | 60 | struct cds_lfht_node { |
cc4fcb10 | 61 | /* cache-hot for iteration */ |
14044b37 | 62 | struct _cds_lfht_node p; /* needs to be first field */ |
9b35f1e4 MD |
63 | void *key; |
64 | unsigned int key_len; | |
9b35f1e4 | 65 | /* cache-cold for iteration */ |
abc490a1 MD |
66 | struct rcu_head head; |
67 | }; | |
68 | ||
7f52427b | 69 | /* cds_lfht_iter: Used to track state while traversing a hash chain. */ |
adc0de68 MD |
70 | struct cds_lfht_iter { |
71 | struct cds_lfht_node *node, *next; | |
72 | }; | |
73 | ||
74 | static inline | |
75 | struct cds_lfht_node *cds_lfht_iter_get_node(struct cds_lfht_iter *iter) | |
76 | { | |
77 | return iter->node; | |
78 | } | |
79 | ||
14044b37 | 80 | struct cds_lfht; |
ab7d5fc6 | 81 | |
5e28c532 MD |
82 | /* |
83 | * Caution ! | |
abc490a1 | 84 | * Ensure reader and writer threads are registered as urcu readers. |
5e28c532 MD |
85 | */ |
86 | ||
14044b37 MD |
87 | typedef unsigned long (*cds_lfht_hash_fct)(void *key, size_t length, |
88 | unsigned long seed); | |
89 | typedef unsigned long (*cds_lfht_compare_fct)(void *key1, size_t key1_len, | |
90 | void *key2, size_t key2_len); | |
abc490a1 | 91 | |
f0c29ed7 | 92 | /* |
14044b37 | 93 | * cds_lfht_node_init - initialize a hash table node |
f0c29ed7 | 94 | */ |
abc490a1 | 95 | static inline |
14044b37 MD |
96 | void cds_lfht_node_init(struct cds_lfht_node *node, void *key, |
97 | size_t key_len) | |
abc490a1 MD |
98 | { |
99 | node->key = key; | |
732ad076 | 100 | node->key_len = key_len; |
abc490a1 | 101 | } |
674f7a69 | 102 | |
b8af5011 MD |
103 | /* |
104 | * Hash table creation flags. | |
105 | */ | |
106 | enum { | |
107 | CDS_LFHT_AUTO_RESIZE = (1U << 0), | |
5afadd12 | 108 | CDS_LFHT_ACCOUNTING = (1U << 1), |
b8af5011 MD |
109 | }; |
110 | ||
674f7a69 | 111 | /* |
7a9dcf9b | 112 | * _cds_lfht_new - API used by cds_lfht_new wrapper. Do not use directly. |
674f7a69 | 113 | */ |
7a9dcf9b | 114 | struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct, |
14044b37 MD |
115 | cds_lfht_compare_fct compare_fct, |
116 | unsigned long hash_seed, | |
117 | unsigned long init_size, | |
5488222b | 118 | unsigned long min_alloc_size, |
b8af5011 | 119 | int flags, |
14044b37 | 120 | void (*cds_lfht_call_rcu)(struct rcu_head *head, |
1475579c | 121 | void (*func)(struct rcu_head *head)), |
01dbfa62 MD |
122 | void (*cds_lfht_synchronize_rcu)(void), |
123 | void (*cds_lfht_rcu_read_lock)(void), | |
5f511391 MD |
124 | void (*cds_lfht_rcu_read_unlock)(void), |
125 | void (*cds_lfht_rcu_thread_offline)(void), | |
b7d619b0 MD |
126 | void (*cds_lfht_rcu_thread_online)(void), |
127 | void (*cds_lfht_rcu_register_thread)(void), | |
128 | void (*cds_lfht_rcu_unregister_thread)(void), | |
129 | pthread_attr_t *attr); | |
ab7d5fc6 | 130 | |
7a9dcf9b MD |
131 | /* |
132 | * cds_lfht_new - allocate a hash table. | |
f22dd01d MD |
133 | * @hash_fct: the hashing function. |
134 | * @compare_fct: the key comparison function. | |
135 | * @hash_seed: the seed for hash function. | |
136 | * @init_size: number of nodes to allocate initially. Must be power of two. | |
5488222b | 137 | * @min_alloc_size: the smallest allocation size to use. Must be power of two. |
f22dd01d MD |
138 | * @flags: hash table creation flags (can be combined with bitwise or: '|'). |
139 | * 0: no flags. | |
140 | * CDS_LFHT_AUTO_RESIZE: automatically resize hash table. | |
b7d619b0 | 141 | * @attr: optional resize worker thread attributes. NULL for default. |
7a9dcf9b | 142 | * |
7a9dcf9b MD |
143 | * Return NULL on error. |
144 | * Note: the RCU flavor must be already included before the hash table header. | |
b7d619b0 MD |
145 | * |
146 | * The programmer is responsible for ensuring that resize operation has a | |
147 | * priority equal to hash table updater threads. It should be performed by | |
148 | * specifying the appropriate priority in the pthread "attr" argument, and, | |
149 | * for CDS_LFHT_AUTO_RESIZE, by ensuring that call_rcu worker threads also have | |
150 | * this priority level. Having lower priority for call_rcu and resize threads | |
151 | * does not pose any correctness issue, but the resize operations could be | |
152 | * starved by updates, thus leading to long hash table bucket chains. | |
3df0c49c | 153 | * Threads calling this API need to be registered RCU read-side threads. |
7a9dcf9b MD |
154 | */ |
155 | static inline | |
156 | struct cds_lfht *cds_lfht_new(cds_lfht_hash_fct hash_fct, | |
157 | cds_lfht_compare_fct compare_fct, | |
158 | unsigned long hash_seed, | |
159 | unsigned long init_size, | |
5488222b | 160 | unsigned long min_alloc_size, |
b7d619b0 MD |
161 | int flags, |
162 | pthread_attr_t *attr) | |
7a9dcf9b MD |
163 | { |
164 | return _cds_lfht_new(hash_fct, compare_fct, hash_seed, | |
5488222b | 165 | init_size, min_alloc_size, flags, |
7a9dcf9b MD |
166 | call_rcu, synchronize_rcu, rcu_read_lock, |
167 | rcu_read_unlock, rcu_thread_offline, | |
b7d619b0 MD |
168 | rcu_thread_online, rcu_register_thread, |
169 | rcu_unregister_thread, attr); | |
7a9dcf9b MD |
170 | } |
171 | ||
f0c29ed7 | 172 | /* |
14044b37 | 173 | * cds_lfht_destroy - destroy a hash table. |
b7d619b0 MD |
174 | * @ht: the hash table to destroy. |
175 | * @attr: (output) resize worker thread attributes, as received by cds_lfht_new. | |
176 | * The caller will typically want to free this pointer if dynamically | |
7f52427b MD |
177 | * allocated. The attr point can be NULL if the caller does not |
178 | * need to be informed of the value passed to cds_lfht_new(). | |
6878c72b MD |
179 | * |
180 | * Return 0 on success, negative error value on error. | |
3df0c49c | 181 | * Threads calling this API need to be registered RCU read-side threads. |
f0c29ed7 | 182 | */ |
b7d619b0 | 183 | int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr); |
f0c29ed7 MD |
184 | |
185 | /* | |
14044b37 | 186 | * cds_lfht_count_nodes - count the number of nodes in the hash table. |
7f52427b MD |
187 | * @ht: the hash table. |
188 | * @split_count_before: Sample the node count split-counter before traversal. | |
189 | * @count: Traverse the hash table, count the number of nodes observed. | |
190 | * @removed: Number of logically removed nodes observed during traversal. | |
191 | * @split_count_after: Sample the node count split-counter after traversal. | |
f0c29ed7 | 192 | * Call with rcu_read_lock held. |
3df0c49c | 193 | * Threads calling this API need to be registered RCU read-side threads. |
f0c29ed7 | 194 | */ |
14044b37 | 195 | void cds_lfht_count_nodes(struct cds_lfht *ht, |
7f52427b | 196 | long *split_count_before, |
adc0de68 | 197 | unsigned long *count, |
973e5e1b | 198 | unsigned long *removed, |
7f52427b | 199 | long *split_count_after); |
ab7d5fc6 | 200 | |
f0c29ed7 | 201 | /* |
14044b37 | 202 | * cds_lfht_lookup - lookup a node by key. |
f0c29ed7 | 203 | * |
adc0de68 | 204 | * Output in "*iter". *iter->node set to NULL if not found. |
f0c29ed7 | 205 | * Call with rcu_read_lock held. |
3df0c49c | 206 | * Threads calling this API need to be registered RCU read-side threads. |
f0c29ed7 | 207 | */ |
adc0de68 MD |
208 | void cds_lfht_lookup(struct cds_lfht *ht, void *key, size_t key_len, |
209 | struct cds_lfht_iter *iter); | |
ab7d5fc6 | 210 | |
f0c29ed7 | 211 | /* |
3883c0e5 | 212 | * cds_lfht_next_duplicate - get the next item with same key (after a lookup). |
f0c29ed7 | 213 | * |
adc0de68 MD |
214 | * Uses an iterator initialized by a lookup. |
215 | * Sets *iter-node to the following node with same key. | |
216 | * Sets *iter->node to NULL if no following node exists with same key. | |
217 | * RCU read-side lock must be held across cds_lfht_lookup and | |
218 | * cds_lfht_next calls, and also between cds_lfht_next calls using the | |
219 | * node returned by a previous cds_lfht_next. | |
220 | * Call with rcu_read_lock held. | |
3df0c49c | 221 | * Threads calling this API need to be registered RCU read-side threads. |
f0c29ed7 | 222 | */ |
3883c0e5 | 223 | void cds_lfht_next_duplicate(struct cds_lfht *ht, struct cds_lfht_iter *iter); |
4e9b9fbf MD |
224 | |
225 | /* | |
226 | * cds_lfht_first - get the first node in the table. | |
227 | * | |
228 | * Output in "*iter". *iter->node set to NULL if table is empty. | |
229 | * Call with rcu_read_lock held. | |
3df0c49c | 230 | * Threads calling this API need to be registered RCU read-side threads. |
4e9b9fbf MD |
231 | */ |
232 | void cds_lfht_first(struct cds_lfht *ht, struct cds_lfht_iter *iter); | |
233 | ||
234 | /* | |
235 | * cds_lfht_next - get the next node in the table. | |
236 | * | |
237 | * Input/Output in "*iter". *iter->node set to NULL if *iter was | |
238 | * pointing to the last table node. | |
239 | * Call with rcu_read_lock held. | |
3df0c49c | 240 | * Threads calling this API need to be registered RCU read-side threads. |
4e9b9fbf MD |
241 | */ |
242 | void cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_iter *iter); | |
ab7d5fc6 | 243 | |
18117871 | 244 | /* |
14044b37 | 245 | * cds_lfht_add - add a node to the hash table. |
f0c29ed7 | 246 | * |
48ed1c18 | 247 | * This function supports adding redundant keys into the table. |
3df0c49c MD |
248 | * Call with rcu_read_lock held. |
249 | * Threads calling this API need to be registered RCU read-side threads. | |
f0c29ed7 | 250 | */ |
14044b37 | 251 | void cds_lfht_add(struct cds_lfht *ht, struct cds_lfht_node *node); |
f0c29ed7 MD |
252 | |
253 | /* | |
14044b37 | 254 | * cds_lfht_add_unique - add a node to hash table, if key is not present. |
f0c29ed7 | 255 | * |
6878c72b | 256 | * Return the node added upon success. |
860d07e8 MD |
257 | * Return the unique node already present upon failure. If |
258 | * cds_lfht_add_unique fails, the node passed as parameter should be | |
259 | * freed by the caller. | |
f0c29ed7 | 260 | * Call with rcu_read_lock held. |
3df0c49c | 261 | * Threads calling this API need to be registered RCU read-side threads. |
48ed1c18 MD |
262 | * |
263 | * The semantic of this function is that if only this function is used | |
264 | * to add keys into the table, no duplicated keys should ever be | |
265 | * observable in the table. The same guarantee apply for combination of | |
9357c415 | 266 | * add_unique and add_replace (see below). |
18117871 | 267 | */ |
adc0de68 MD |
268 | struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, |
269 | struct cds_lfht_node *node); | |
3eca1b8c | 270 | |
48ed1c18 | 271 | /* |
9357c415 | 272 | * cds_lfht_add_replace - replace or add a node within hash table. |
48ed1c18 MD |
273 | * |
274 | * Return the node replaced upon success. If no node matching the key | |
275 | * was present, return NULL, which also means the operation succeeded. | |
276 | * This replacement operation should never fail. | |
277 | * Call with rcu_read_lock held. | |
3df0c49c | 278 | * Threads calling this API need to be registered RCU read-side threads. |
48ed1c18 MD |
279 | * After successful replacement, a grace period must be waited for before |
280 | * freeing the memory reserved for the returned node. | |
281 | * | |
282 | * The semantic of replacement vs lookups is the following: if lookups | |
9357c415 MD |
283 | * are performed between a key unique insertion and its removal, we |
284 | * guarantee that the lookups and get next will always find exactly one | |
285 | * instance of the key if it is replaced concurrently with the lookups. | |
48ed1c18 MD |
286 | * |
287 | * Providing this semantic allows us to ensure that replacement-only | |
288 | * schemes will never generate duplicated keys. It also allows us to | |
9357c415 | 289 | * guarantee that a combination of add_replace and add_unique updates |
48ed1c18 MD |
290 | * will never generate duplicated keys. |
291 | */ | |
9357c415 | 292 | struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht, |
adc0de68 | 293 | struct cds_lfht_node *node); |
48ed1c18 | 294 | |
f0c29ed7 | 295 | /* |
9357c415 | 296 | * cds_lfht_replace - replace a node pointer to by iter within hash table. |
f0c29ed7 | 297 | * |
9357c415 MD |
298 | * Return 0 if replacement is successful, negative value otherwise. |
299 | * Replacing a NULL old node or an already removed node will fail with a | |
300 | * negative value. | |
301 | * Old node can be looked up with cds_lfht_lookup and cds_lfht_next. | |
302 | * RCU read-side lock must be held between lookup and replacement. | |
303 | * Call with rcu_read_lock held. | |
3df0c49c | 304 | * Threads calling this API need to be registered RCU read-side threads. |
9357c415 MD |
305 | * After successful replacement, a grace period must be waited for before |
306 | * freeing the memory reserved for the old node (which can be accessed | |
307 | * with cds_lfht_iter_get_node). | |
308 | * | |
309 | * The semantic of replacement vs lookups is the following: if lookups | |
310 | * are performed between a key unique insertion and its removal, we | |
311 | * guarantee that the lookups and get next will always find exactly one | |
312 | * instance of the key if it is replaced concurrently with the lookups. | |
313 | * | |
314 | * Providing this semantic allows us to ensure that replacement-only | |
315 | * schemes will never generate duplicated keys. It also allows us to | |
316 | * guarantee that a combination of add_replace and add_unique updates | |
317 | * will never generate duplicated keys. | |
318 | */ | |
319 | int cds_lfht_replace(struct cds_lfht *ht, struct cds_lfht_iter *old_iter, | |
320 | struct cds_lfht_node *new_node); | |
321 | ||
322 | /* | |
323 | * cds_lfht_del - remove node pointed to by iterator from hash table. | |
324 | * | |
325 | * Return 0 if the node is successfully removed, negative value | |
326 | * otherwise. | |
327 | * Replacing a NULL node or an already removed node will fail with a | |
328 | * negative value. | |
329 | * Node can be looked up with cds_lfht_lookup and cds_lfht_next. | |
330 | * cds_lfht_iter_get_node. | |
331 | * RCU read-side lock must be held between lookup and removal. | |
f0c29ed7 | 332 | * Call with rcu_read_lock held. |
3df0c49c | 333 | * Threads calling this API need to be registered RCU read-side threads. |
48ed1c18 | 334 | * After successful removal, a grace period must be waited for before |
9357c415 MD |
335 | * freeing the memory reserved for old node (which can be accessed with |
336 | * cds_lfht_iter_get_node). | |
f0c29ed7 | 337 | */ |
9357c415 | 338 | int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_iter *iter); |
ab7d5fc6 | 339 | |
f0c29ed7 | 340 | /* |
14044b37 | 341 | * cds_lfht_resize - Force a hash table resize |
1475579c | 342 | * @new_size: update to this hash table size. |
3df0c49c MD |
343 | * |
344 | * Threads calling this API need to be registered RCU read-side threads. | |
f0c29ed7 | 345 | */ |
1475579c | 346 | void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size); |
464a1ec9 | 347 | |
01389791 MD |
348 | #ifdef __cplusplus |
349 | } | |
350 | #endif | |
351 | ||
a42cc659 | 352 | #endif /* _URCU_RCULFHASH_H */ |