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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> | |
0dcf4847 | 10 | * Copyright 2011 - Lai Jiangshan <laijs@cn.fujitsu.com> |
f0c29ed7 MD |
11 | * |
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. | |
16 | * | |
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. | |
21 | * | |
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 | |
cf77d1fa MD |
25 | * |
26 | * Include this file _after_ including your URCU flavor. | |
f0c29ed7 MD |
27 | */ |
28 | ||
674f7a69 | 29 | #include <stdint.h> |
6d320126 | 30 | #include <urcu/compiler.h> |
abc490a1 | 31 | #include <urcu-call-rcu.h> |
7b17c13e | 32 | #include <urcu-flavor.h> |
abc490a1 | 33 | |
01389791 MD |
34 | #ifdef __cplusplus |
35 | extern "C" { | |
36 | #endif | |
37 | ||
7f52427b | 38 | /* |
04db56f8 | 39 | * cds_lfht_node: Contains the next pointers and reverse-hash |
7f52427b | 40 | * value required for lookup and traversal of the hash table. |
04db56f8 LJ |
41 | * |
42 | * struct cds_lfht_node should be aligned on 4-bytes boundaries because | |
43 | * the two lower bits are used as flags. | |
7f52427b | 44 | * |
ae62aa6a MD |
45 | * struct cds_lfht_node can be embedded into a structure (as a field). |
46 | * caa_container_of() can be used to get the structure from the struct | |
47 | * cds_lfht_node after a lookup. | |
04db56f8 LJ |
48 | * |
49 | * The structure which embeds it typically holds the key (or key-value | |
50 | * pair) of the object. The caller code is responsible for calculation | |
51 | * of the hash value for cds_lfht APIs. | |
ae62aa6a | 52 | */ |
14044b37 | 53 | struct cds_lfht_node { |
1ee8f000 | 54 | struct cds_lfht_node *next; /* ptr | BUCKET_FLAG | REMOVED_FLAG */ |
04db56f8 LJ |
55 | unsigned long reverse_hash; |
56 | } __attribute__((aligned(4))); | |
abc490a1 | 57 | |
7f52427b | 58 | /* cds_lfht_iter: Used to track state while traversing a hash chain. */ |
adc0de68 MD |
59 | struct cds_lfht_iter { |
60 | struct cds_lfht_node *node, *next; | |
61 | }; | |
62 | ||
63 | static inline | |
64 | struct cds_lfht_node *cds_lfht_iter_get_node(struct cds_lfht_iter *iter) | |
65 | { | |
66 | return iter->node; | |
67 | } | |
68 | ||
14044b37 | 69 | struct cds_lfht; |
ab7d5fc6 | 70 | |
5e28c532 MD |
71 | /* |
72 | * Caution ! | |
abc490a1 | 73 | * Ensure reader and writer threads are registered as urcu readers. |
5e28c532 MD |
74 | */ |
75 | ||
996ff57c | 76 | typedef int (*cds_lfht_match_fct)(struct cds_lfht_node *node, const void *key); |
abc490a1 | 77 | |
f0c29ed7 | 78 | /* |
14044b37 | 79 | * cds_lfht_node_init - initialize a hash table node |
0422d92c | 80 | * @node: the node to initialize. |
04db56f8 LJ |
81 | * |
82 | * This function is kept to be eventually used for debugging purposes | |
83 | * (detection of memory corruption). | |
f0c29ed7 | 84 | */ |
abc490a1 | 85 | static inline |
04db56f8 | 86 | void cds_lfht_node_init(struct cds_lfht_node *node) |
abc490a1 | 87 | { |
abc490a1 | 88 | } |
674f7a69 | 89 | |
b8af5011 MD |
90 | /* |
91 | * Hash table creation flags. | |
92 | */ | |
93 | enum { | |
94 | CDS_LFHT_AUTO_RESIZE = (1U << 0), | |
5afadd12 | 95 | CDS_LFHT_ACCOUNTING = (1U << 1), |
b8af5011 MD |
96 | }; |
97 | ||
0b6aa001 LJ |
98 | struct cds_lfht_mm_type { |
99 | struct cds_lfht *(*alloc_cds_lfht)(unsigned long min_nr_alloc_buckets, | |
100 | unsigned long max_nr_buckets); | |
101 | void (*alloc_bucket_table)(struct cds_lfht *ht, unsigned long order); | |
102 | void (*free_bucket_table)(struct cds_lfht *ht, unsigned long order); | |
103 | struct cds_lfht_node *(*bucket_at)(struct cds_lfht *ht, | |
104 | unsigned long index); | |
105 | }; | |
106 | ||
107 | extern const struct cds_lfht_mm_type cds_lfht_mm_order; | |
108 | ||
674f7a69 | 109 | /* |
7a9dcf9b | 110 | * _cds_lfht_new - API used by cds_lfht_new wrapper. Do not use directly. |
674f7a69 | 111 | */ |
0422d92c | 112 | struct cds_lfht *_cds_lfht_new(unsigned long init_size, |
0722081a | 113 | unsigned long min_nr_alloc_buckets, |
747d725c | 114 | unsigned long max_nr_buckets, |
b8af5011 | 115 | int flags, |
0b6aa001 | 116 | const struct cds_lfht_mm_type *mm, |
7b17c13e | 117 | const struct rcu_flavor_struct *flavor, |
b7d619b0 | 118 | pthread_attr_t *attr); |
ab7d5fc6 | 119 | |
7a9dcf9b MD |
120 | /* |
121 | * cds_lfht_new - allocate a hash table. | |
747d725c LJ |
122 | * @init_size: number of buckets to allocate initially. Must be power of two. |
123 | * @min_nr_alloc_buckets: the minimum number of allocated buckets. | |
124 | * (must be power of two) | |
125 | * @max_nr_buckets: the maximum number of hash table buckets allowed. | |
126 | * (must be power of two) | |
f22dd01d MD |
127 | * @flags: hash table creation flags (can be combined with bitwise or: '|'). |
128 | * 0: no flags. | |
129 | * CDS_LFHT_AUTO_RESIZE: automatically resize hash table. | |
44bbe7fa LJ |
130 | * CDS_LFHT_ACCOUNTING: count the number of node addition |
131 | * and removal in the table | |
b7d619b0 | 132 | * @attr: optional resize worker thread attributes. NULL for default. |
7a9dcf9b | 133 | * |
7a9dcf9b MD |
134 | * Return NULL on error. |
135 | * Note: the RCU flavor must be already included before the hash table header. | |
b7d619b0 MD |
136 | * |
137 | * The programmer is responsible for ensuring that resize operation has a | |
138 | * priority equal to hash table updater threads. It should be performed by | |
139 | * specifying the appropriate priority in the pthread "attr" argument, and, | |
140 | * for CDS_LFHT_AUTO_RESIZE, by ensuring that call_rcu worker threads also have | |
141 | * this priority level. Having lower priority for call_rcu and resize threads | |
142 | * does not pose any correctness issue, but the resize operations could be | |
143 | * starved by updates, thus leading to long hash table bucket chains. | |
44bbe7fa LJ |
144 | * Threads calling this API are NOT required to be registered RCU read-side |
145 | * threads. It can be called very early.(before rcu is initialized ...etc.) | |
7a9dcf9b MD |
146 | */ |
147 | static inline | |
0422d92c | 148 | struct cds_lfht *cds_lfht_new(unsigned long init_size, |
0722081a | 149 | unsigned long min_nr_alloc_buckets, |
747d725c | 150 | unsigned long max_nr_buckets, |
b7d619b0 MD |
151 | int flags, |
152 | pthread_attr_t *attr) | |
7a9dcf9b | 153 | { |
7b17c13e | 154 | return _cds_lfht_new(init_size, min_nr_alloc_buckets, max_nr_buckets, |
0b6aa001 | 155 | flags, &cds_lfht_mm_order, &rcu_flavor, attr); |
7a9dcf9b MD |
156 | } |
157 | ||
f0c29ed7 | 158 | /* |
14044b37 | 159 | * cds_lfht_destroy - destroy a hash table. |
b7d619b0 MD |
160 | * @ht: the hash table to destroy. |
161 | * @attr: (output) resize worker thread attributes, as received by cds_lfht_new. | |
162 | * The caller will typically want to free this pointer if dynamically | |
7f52427b MD |
163 | * allocated. The attr point can be NULL if the caller does not |
164 | * need to be informed of the value passed to cds_lfht_new(). | |
6878c72b MD |
165 | * |
166 | * Return 0 on success, negative error value on error. | |
3df0c49c | 167 | * Threads calling this API need to be registered RCU read-side threads. |
f0c29ed7 | 168 | */ |
b7d619b0 | 169 | int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr); |
f0c29ed7 MD |
170 | |
171 | /* | |
14044b37 | 172 | * cds_lfht_count_nodes - count the number of nodes in the hash table. |
7f52427b MD |
173 | * @ht: the hash table. |
174 | * @split_count_before: Sample the node count split-counter before traversal. | |
175 | * @count: Traverse the hash table, count the number of nodes observed. | |
176 | * @removed: Number of logically removed nodes observed during traversal. | |
177 | * @split_count_after: Sample the node count split-counter after traversal. | |
0422d92c | 178 | * |
f0c29ed7 | 179 | * Call with rcu_read_lock held. |
3df0c49c | 180 | * Threads calling this API need to be registered RCU read-side threads. |
f0c29ed7 | 181 | */ |
14044b37 | 182 | void cds_lfht_count_nodes(struct cds_lfht *ht, |
7f52427b | 183 | long *split_count_before, |
adc0de68 | 184 | unsigned long *count, |
973e5e1b | 185 | unsigned long *removed, |
7f52427b | 186 | long *split_count_after); |
ab7d5fc6 | 187 | |
f0c29ed7 | 188 | /* |
14044b37 | 189 | * cds_lfht_lookup - lookup a node by key. |
0422d92c | 190 | * @ht: the hash table. |
0422d92c | 191 | * @hash: the key hash. |
6f554439 LJ |
192 | * @match: the key match function. |
193 | * @key: the current node key. | |
0422d92c | 194 | * @iter: Node, if found (output). *iter->node set to NULL if not found. |
f0c29ed7 | 195 | * |
f0c29ed7 | 196 | * Call with rcu_read_lock held. |
3df0c49c | 197 | * Threads calling this API need to be registered RCU read-side threads. |
f0c29ed7 | 198 | */ |
6f554439 | 199 | void cds_lfht_lookup(struct cds_lfht *ht, unsigned long hash, |
996ff57c | 200 | cds_lfht_match_fct match, const void *key, |
6f554439 | 201 | struct cds_lfht_iter *iter); |
ab7d5fc6 | 202 | |
f0c29ed7 | 203 | /* |
3883c0e5 | 204 | * cds_lfht_next_duplicate - get the next item with same key (after a lookup). |
0422d92c MD |
205 | * @ht: the hash table. |
206 | * @match: the key match function. | |
04db56f8 | 207 | * @key: the current node key. |
0422d92c | 208 | * @iter: Node, if found (output). *iter->node set to NULL if not found. |
f0c29ed7 | 209 | * |
adc0de68 MD |
210 | * Uses an iterator initialized by a lookup. |
211 | * Sets *iter-node to the following node with same key. | |
212 | * Sets *iter->node to NULL if no following node exists with same key. | |
213 | * RCU read-side lock must be held across cds_lfht_lookup and | |
214 | * cds_lfht_next calls, and also between cds_lfht_next calls using the | |
215 | * node returned by a previous cds_lfht_next. | |
216 | * Call with rcu_read_lock held. | |
3df0c49c | 217 | * Threads calling this API need to be registered RCU read-side threads. |
f0c29ed7 | 218 | */ |
0422d92c | 219 | void cds_lfht_next_duplicate(struct cds_lfht *ht, |
996ff57c | 220 | cds_lfht_match_fct match, const void *key, |
04db56f8 | 221 | struct cds_lfht_iter *iter); |
4e9b9fbf MD |
222 | |
223 | /* | |
224 | * cds_lfht_first - get the first node in the table. | |
0422d92c MD |
225 | * @ht: the hash table. |
226 | * @iter: First node, if exists (output). *iter->node set to NULL if not found. | |
4e9b9fbf MD |
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. | |
0422d92c MD |
236 | * @ht: the hash table. |
237 | * @iter: Next node, if exists (output). *iter->node set to NULL if not found. | |
4e9b9fbf MD |
238 | * |
239 | * Input/Output in "*iter". *iter->node set to NULL if *iter was | |
240 | * pointing to the last table node. | |
241 | * Call with rcu_read_lock held. | |
3df0c49c | 242 | * Threads calling this API need to be registered RCU read-side threads. |
4e9b9fbf MD |
243 | */ |
244 | void cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_iter *iter); | |
ab7d5fc6 | 245 | |
18117871 | 246 | /* |
14044b37 | 247 | * cds_lfht_add - add a node to the hash table. |
0422d92c MD |
248 | * @ht: the hash table. |
249 | * @hash: the key hash. | |
250 | * @node: the node to add. | |
f0c29ed7 | 251 | * |
48ed1c18 | 252 | * This function supports adding redundant keys into the table. |
3df0c49c MD |
253 | * Call with rcu_read_lock held. |
254 | * Threads calling this API need to be registered RCU read-side threads. | |
f0c29ed7 | 255 | */ |
0422d92c MD |
256 | void cds_lfht_add(struct cds_lfht *ht, unsigned long hash, |
257 | struct cds_lfht_node *node); | |
f0c29ed7 MD |
258 | |
259 | /* | |
14044b37 | 260 | * cds_lfht_add_unique - add a node to hash table, if key is not present. |
0422d92c | 261 | * @ht: the hash table. |
6f554439 | 262 | * @hash: the node's hash. |
0422d92c | 263 | * @match: the key match function. |
04db56f8 | 264 | * @key: the node's key. |
0422d92c | 265 | * @node: the node to try adding. |
f0c29ed7 | 266 | * |
6878c72b | 267 | * Return the node added upon success. |
860d07e8 MD |
268 | * Return the unique node already present upon failure. If |
269 | * cds_lfht_add_unique fails, the node passed as parameter should be | |
270 | * freed by the caller. | |
f0c29ed7 | 271 | * Call with rcu_read_lock held. |
3df0c49c | 272 | * Threads calling this API need to be registered RCU read-side threads. |
48ed1c18 MD |
273 | * |
274 | * The semantic of this function is that if only this function is used | |
275 | * to add keys into the table, no duplicated keys should ever be | |
276 | * observable in the table. The same guarantee apply for combination of | |
9357c415 | 277 | * add_unique and add_replace (see below). |
18117871 | 278 | */ |
adc0de68 | 279 | struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, |
6f554439 | 280 | unsigned long hash, |
0422d92c | 281 | cds_lfht_match_fct match, |
996ff57c | 282 | const void *key, |
adc0de68 | 283 | struct cds_lfht_node *node); |
3eca1b8c | 284 | |
48ed1c18 | 285 | /* |
9357c415 | 286 | * cds_lfht_add_replace - replace or add a node within hash table. |
0422d92c | 287 | * @ht: the hash table. |
6f554439 | 288 | * @hash: the node's hash. |
0422d92c | 289 | * @match: the key match function. |
04db56f8 | 290 | * @key: the node's key. |
0422d92c | 291 | * @node: the node to add. |
48ed1c18 MD |
292 | * |
293 | * Return the node replaced upon success. If no node matching the key | |
294 | * was present, return NULL, which also means the operation succeeded. | |
295 | * This replacement operation should never fail. | |
296 | * Call with rcu_read_lock held. | |
3df0c49c | 297 | * Threads calling this API need to be registered RCU read-side threads. |
48ed1c18 MD |
298 | * After successful replacement, a grace period must be waited for before |
299 | * freeing the memory reserved for the returned node. | |
300 | * | |
301 | * The semantic of replacement vs lookups is the following: if lookups | |
9357c415 MD |
302 | * are performed between a key unique insertion and its removal, we |
303 | * guarantee that the lookups and get next will always find exactly one | |
304 | * instance of the key if it is replaced concurrently with the lookups. | |
48ed1c18 MD |
305 | * |
306 | * Providing this semantic allows us to ensure that replacement-only | |
307 | * schemes will never generate duplicated keys. It also allows us to | |
9357c415 | 308 | * guarantee that a combination of add_replace and add_unique updates |
48ed1c18 MD |
309 | * will never generate duplicated keys. |
310 | */ | |
9357c415 | 311 | struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht, |
6f554439 | 312 | unsigned long hash, |
0422d92c | 313 | cds_lfht_match_fct match, |
996ff57c | 314 | const void *key, |
adc0de68 | 315 | struct cds_lfht_node *node); |
48ed1c18 | 316 | |
f0c29ed7 | 317 | /* |
9357c415 | 318 | * cds_lfht_replace - replace a node pointer to by iter within hash table. |
0422d92c MD |
319 | * @ht: the hash table. |
320 | * @old_iter: the iterator position of the node to replace. | |
321 | * @now_node: the new node to try using for replacement. | |
f0c29ed7 | 322 | * |
9357c415 MD |
323 | * Return 0 if replacement is successful, negative value otherwise. |
324 | * Replacing a NULL old node or an already removed node will fail with a | |
325 | * negative value. | |
326 | * Old node can be looked up with cds_lfht_lookup and cds_lfht_next. | |
327 | * RCU read-side lock must be held between lookup and replacement. | |
328 | * Call with rcu_read_lock held. | |
3df0c49c | 329 | * Threads calling this API need to be registered RCU read-side threads. |
9357c415 MD |
330 | * After successful replacement, a grace period must be waited for before |
331 | * freeing the memory reserved for the old node (which can be accessed | |
332 | * with cds_lfht_iter_get_node). | |
333 | * | |
334 | * The semantic of replacement vs lookups is the following: if lookups | |
335 | * are performed between a key unique insertion and its removal, we | |
336 | * guarantee that the lookups and get next will always find exactly one | |
337 | * instance of the key if it is replaced concurrently with the lookups. | |
338 | * | |
339 | * Providing this semantic allows us to ensure that replacement-only | |
340 | * schemes will never generate duplicated keys. It also allows us to | |
341 | * guarantee that a combination of add_replace and add_unique updates | |
342 | * will never generate duplicated keys. | |
343 | */ | |
344 | int cds_lfht_replace(struct cds_lfht *ht, struct cds_lfht_iter *old_iter, | |
345 | struct cds_lfht_node *new_node); | |
346 | ||
347 | /* | |
348 | * cds_lfht_del - remove node pointed to by iterator from hash table. | |
0422d92c MD |
349 | * @ht: the hash table. |
350 | * @iter: the iterator position of the node to delete. | |
9357c415 MD |
351 | * |
352 | * Return 0 if the node is successfully removed, negative value | |
353 | * otherwise. | |
354 | * Replacing a NULL node or an already removed node will fail with a | |
355 | * negative value. | |
356 | * Node can be looked up with cds_lfht_lookup and cds_lfht_next. | |
357 | * cds_lfht_iter_get_node. | |
358 | * RCU read-side lock must be held between lookup and removal. | |
f0c29ed7 | 359 | * Call with rcu_read_lock held. |
3df0c49c | 360 | * Threads calling this API need to be registered RCU read-side threads. |
48ed1c18 | 361 | * After successful removal, a grace period must be waited for before |
9357c415 MD |
362 | * freeing the memory reserved for old node (which can be accessed with |
363 | * cds_lfht_iter_get_node). | |
f0c29ed7 | 364 | */ |
9357c415 | 365 | int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_iter *iter); |
ab7d5fc6 | 366 | |
f0c29ed7 | 367 | /* |
14044b37 | 368 | * cds_lfht_resize - Force a hash table resize |
0422d92c | 369 | * @ht: the hash table. |
1475579c | 370 | * @new_size: update to this hash table size. |
3df0c49c MD |
371 | * |
372 | * Threads calling this API need to be registered RCU read-side threads. | |
f0c29ed7 | 373 | */ |
1475579c | 374 | void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size); |
464a1ec9 | 375 | |
6d320126 MD |
376 | /* |
377 | * Note: cds_lfht_for_each are safe for element removal during | |
378 | * iteration. | |
379 | */ | |
380 | #define cds_lfht_for_each(ht, iter, node) \ | |
381 | for (cds_lfht_first(ht, iter), \ | |
382 | node = cds_lfht_iter_get_node(iter); \ | |
383 | node != NULL; \ | |
384 | cds_lfht_next(ht, iter), \ | |
385 | node = cds_lfht_iter_get_node(iter)) | |
386 | ||
6f554439 LJ |
387 | #define cds_lfht_for_each_duplicate(ht, hash, match, key, iter, node) \ |
388 | for (cds_lfht_lookup(ht, hash, match, key, iter), \ | |
6d320126 MD |
389 | node = cds_lfht_iter_get_node(iter); \ |
390 | node != NULL; \ | |
391 | cds_lfht_next_duplicate(ht, match, key, iter), \ | |
392 | node = cds_lfht_iter_get_node(iter)) | |
393 | ||
394 | #define cds_lfht_for_each_entry(ht, iter, pos, member) \ | |
395 | for (cds_lfht_first(ht, iter), \ | |
396 | pos = caa_container_of(cds_lfht_iter_get_node(iter), \ | |
397 | typeof(*(pos)), member); \ | |
0b0627bf | 398 | &(pos)->member != NULL; \ |
6d320126 MD |
399 | cds_lfht_next(ht, iter), \ |
400 | pos = caa_container_of(cds_lfht_iter_get_node(iter), \ | |
401 | typeof(*(pos)), member)) | |
402 | ||
6f554439 | 403 | #define cds_lfht_for_each_entry_duplicate(ht, hash, match, key, \ |
6d320126 | 404 | iter, pos, member) \ |
6f554439 | 405 | for (cds_lfht_lookup(ht, hash, match, key, iter), \ |
6d320126 MD |
406 | pos = caa_container_of(cds_lfht_iter_get_node(iter), \ |
407 | typeof(*(pos)), member); \ | |
0b0627bf | 408 | &(pos)->member != NULL; \ |
6d320126 MD |
409 | cds_lfht_next_duplicate(ht, match, key, iter), \ |
410 | pos = caa_container_of(cds_lfht_iter_get_node(iter), \ | |
411 | typeof(*(pos)), member)) | |
412 | ||
01389791 MD |
413 | #ifdef __cplusplus |
414 | } | |
415 | #endif | |
416 | ||
a42cc659 | 417 | #endif /* _URCU_RCULFHASH_H */ |