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fa68aa62 MD |
1 | #ifndef _URCU_RCULFHASH_H |
2 | #define _URCU_RCULFHASH_H | |
3 | ||
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 | |
24 | * | |
25 | * Include this file _after_ including your URCU flavor. | |
26 | */ | |
27 | ||
28 | #include <stdint.h> | |
29 | #include <urcu-call-rcu.h> | |
30 | ||
31 | #ifdef __cplusplus | |
32 | extern "C" { | |
33 | #endif | |
34 | ||
35 | /* | |
36 | * struct cds_lfht_node and struct _cds_lfht_node should be aligned on | |
37 | * 4-bytes boundaries because the two lower bits are used as flags. | |
38 | */ | |
39 | ||
d6b18934 DG |
40 | /* |
41 | * _cds_lfht_node: Contains the internal pointers and reverse-hash | |
42 | * value required for lookup and traversal of the hash table. | |
43 | */ | |
fa68aa62 MD |
44 | struct _cds_lfht_node { |
45 | struct cds_lfht_node *next; /* ptr | DUMMY_FLAG | REMOVED_FLAG */ | |
46 | unsigned long reverse_hash; | |
47 | } __attribute__((aligned(4))); | |
48 | ||
f6a9efaa | 49 | /* |
d6b18934 DG |
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 | * | |
f6a9efaa DG |
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 | */ | |
fa68aa62 MD |
60 | struct cds_lfht_node { |
61 | /* cache-hot for iteration */ | |
62 | struct _cds_lfht_node p; /* needs to be first field */ | |
63 | void *key; | |
64 | unsigned int key_len; | |
65 | /* cache-cold for iteration */ | |
66 | struct rcu_head head; | |
67 | }; | |
68 | ||
d6b18934 | 69 | /* cds_lfht_iter: Used to track state while traversing a hash chain. */ |
fa68aa62 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 | ||
80 | struct cds_lfht; | |
81 | ||
82 | /* | |
83 | * Caution ! | |
84 | * Ensure reader and writer threads are registered as urcu readers. | |
85 | */ | |
86 | ||
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); | |
91 | ||
92 | /* | |
93 | * cds_lfht_node_init - initialize a hash table node | |
94 | */ | |
95 | static inline | |
96 | void cds_lfht_node_init(struct cds_lfht_node *node, void *key, | |
97 | size_t key_len) | |
98 | { | |
99 | node->key = key; | |
100 | node->key_len = key_len; | |
101 | } | |
102 | ||
103 | /* | |
104 | * Hash table creation flags. | |
105 | */ | |
106 | enum { | |
107 | CDS_LFHT_AUTO_RESIZE = (1U << 0), | |
d6b18934 | 108 | CDS_LFHT_ACCOUNTING = (1U << 1), |
fa68aa62 MD |
109 | }; |
110 | ||
111 | /* | |
112 | * _cds_lfht_new - API used by cds_lfht_new wrapper. Do not use directly. | |
113 | */ | |
114 | struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct, | |
115 | cds_lfht_compare_fct compare_fct, | |
116 | unsigned long hash_seed, | |
117 | unsigned long init_size, | |
d6b18934 | 118 | unsigned long min_alloc_size, |
fa68aa62 MD |
119 | int flags, |
120 | void (*cds_lfht_call_rcu)(struct rcu_head *head, | |
121 | void (*func)(struct rcu_head *head)), | |
122 | void (*cds_lfht_synchronize_rcu)(void), | |
123 | void (*cds_lfht_rcu_read_lock)(void), | |
124 | void (*cds_lfht_rcu_read_unlock)(void), | |
125 | void (*cds_lfht_rcu_thread_offline)(void), | |
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); | |
130 | ||
131 | /* | |
132 | * cds_lfht_new - allocate a hash table. | |
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. | |
d6b18934 | 137 | * @min_alloc_size: the smallest allocation size to use. Must be power of two. |
fa68aa62 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. | |
141 | * @attr: optional resize worker thread attributes. NULL for default. | |
142 | * | |
143 | * Return NULL on error. | |
144 | * Note: the RCU flavor must be already included before the hash table header. | |
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. | |
d6b18934 | 153 | * Threads calling this API need to be registered RCU read-side threads. |
fa68aa62 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, | |
d6b18934 | 160 | unsigned long min_alloc_size, |
fa68aa62 MD |
161 | int flags, |
162 | pthread_attr_t *attr) | |
163 | { | |
164 | return _cds_lfht_new(hash_fct, compare_fct, hash_seed, | |
d6b18934 | 165 | init_size, min_alloc_size, flags, |
fa68aa62 MD |
166 | call_rcu, synchronize_rcu, rcu_read_lock, |
167 | rcu_read_unlock, rcu_thread_offline, | |
168 | rcu_thread_online, rcu_register_thread, | |
169 | rcu_unregister_thread, attr); | |
170 | } | |
171 | ||
172 | /* | |
173 | * cds_lfht_destroy - destroy a hash table. | |
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 | |
d6b18934 DG |
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(). | |
fa68aa62 MD |
179 | * |
180 | * Return 0 on success, negative error value on error. | |
d6b18934 | 181 | * Threads calling this API need to be registered RCU read-side threads. |
fa68aa62 MD |
182 | */ |
183 | int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr); | |
184 | ||
185 | /* | |
186 | * cds_lfht_count_nodes - count the number of nodes in the hash table. | |
d6b18934 DG |
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. | |
fa68aa62 | 192 | * Call with rcu_read_lock held. |
d6b18934 | 193 | * Threads calling this API need to be registered RCU read-side threads. |
fa68aa62 MD |
194 | */ |
195 | void cds_lfht_count_nodes(struct cds_lfht *ht, | |
d6b18934 | 196 | long *split_count_before, |
fa68aa62 MD |
197 | unsigned long *count, |
198 | unsigned long *removed, | |
d6b18934 | 199 | long *split_count_after); |
fa68aa62 MD |
200 | |
201 | /* | |
202 | * cds_lfht_lookup - lookup a node by key. | |
203 | * | |
204 | * Output in "*iter". *iter->node set to NULL if not found. | |
205 | * Call with rcu_read_lock held. | |
d6b18934 | 206 | * Threads calling this API need to be registered RCU read-side threads. |
fa68aa62 MD |
207 | */ |
208 | void cds_lfht_lookup(struct cds_lfht *ht, void *key, size_t key_len, | |
209 | struct cds_lfht_iter *iter); | |
210 | ||
211 | /* | |
f6a9efaa | 212 | * cds_lfht_next_duplicate - get the next item with same key (after a lookup). |
fa68aa62 MD |
213 | * |
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. | |
d6b18934 | 221 | * Threads calling this API need to be registered RCU read-side threads. |
fa68aa62 | 222 | */ |
f6a9efaa DG |
223 | void cds_lfht_next_duplicate(struct cds_lfht *ht, struct cds_lfht_iter *iter); |
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. | |
d6b18934 | 230 | * Threads calling this API need to be registered RCU read-side threads. |
f6a9efaa DG |
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. | |
d6b18934 | 240 | * Threads calling this API need to be registered RCU read-side threads. |
f6a9efaa | 241 | */ |
fa68aa62 MD |
242 | void cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_iter *iter); |
243 | ||
244 | /* | |
245 | * cds_lfht_add - add a node to the hash table. | |
246 | * | |
fa68aa62 | 247 | * This function supports adding redundant keys into the table. |
d6b18934 DG |
248 | * Call with rcu_read_lock held. |
249 | * Threads calling this API need to be registered RCU read-side threads. | |
fa68aa62 MD |
250 | */ |
251 | void cds_lfht_add(struct cds_lfht *ht, struct cds_lfht_node *node); | |
252 | ||
253 | /* | |
254 | * cds_lfht_add_unique - add a node to hash table, if key is not present. | |
255 | * | |
256 | * Return the node added upon success. | |
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. | |
260 | * Call with rcu_read_lock held. | |
d6b18934 | 261 | * Threads calling this API need to be registered RCU read-side threads. |
fa68aa62 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 | |
266 | * add_unique and add_replace (see below). | |
267 | */ | |
268 | struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, | |
269 | struct cds_lfht_node *node); | |
270 | ||
271 | /* | |
272 | * cds_lfht_add_replace - replace or add a node within hash table. | |
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. | |
d6b18934 | 278 | * Threads calling this API need to be registered RCU read-side threads. |
fa68aa62 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 | |
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. | |
286 | * | |
287 | * Providing this semantic allows us to ensure that replacement-only | |
288 | * schemes will never generate duplicated keys. It also allows us to | |
289 | * guarantee that a combination of add_replace and add_unique updates | |
290 | * will never generate duplicated keys. | |
291 | */ | |
292 | struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht, | |
293 | struct cds_lfht_node *node); | |
294 | ||
295 | /* | |
296 | * cds_lfht_replace - replace a node pointer to by iter within hash table. | |
297 | * | |
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. | |
d6b18934 | 304 | * Threads calling this API need to be registered RCU read-side threads. |
fa68aa62 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. | |
332 | * Call with rcu_read_lock held. | |
d6b18934 | 333 | * Threads calling this API need to be registered RCU read-side threads. |
fa68aa62 MD |
334 | * After successful removal, a grace period must be waited for before |
335 | * freeing the memory reserved for old node (which can be accessed with | |
336 | * cds_lfht_iter_get_node). | |
337 | */ | |
338 | int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_iter *iter); | |
339 | ||
340 | /* | |
341 | * cds_lfht_resize - Force a hash table resize | |
342 | * @new_size: update to this hash table size. | |
d6b18934 DG |
343 | * |
344 | * Threads calling this API need to be registered RCU read-side threads. | |
fa68aa62 MD |
345 | */ |
346 | void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size); | |
347 | ||
6636f946 DG |
348 | /* |
349 | * Note: cds_lfht_for_each are safe for element removal during | |
350 | * iteration. | |
351 | */ | |
352 | #define cds_lfht_for_each(ht, iter, node) \ | |
353 | for (cds_lfht_first(ht, iter), \ | |
354 | node = cds_lfht_iter_get_node(iter); \ | |
355 | node != NULL; \ | |
356 | cds_lfht_next(ht, iter), \ | |
357 | node = cds_lfht_iter_get_node(iter)) | |
358 | ||
359 | #define cds_lfht_for_each_duplicate(ht, match, hash, key, iter, node) \ | |
360 | for (cds_lfht_lookup(ht, match, hash, key, iter), \ | |
361 | node = cds_lfht_iter_get_node(iter); \ | |
362 | node != NULL; \ | |
363 | cds_lfht_next_duplicate(ht, match, key, iter), \ | |
364 | node = cds_lfht_iter_get_node(iter)) | |
365 | ||
366 | #define cds_lfht_for_each_entry(ht, iter, pos, member) \ | |
367 | for (cds_lfht_first(ht, iter), \ | |
368 | pos = caa_container_of(cds_lfht_iter_get_node(iter), \ | |
369 | typeof(*(pos)), member); \ | |
5450ed50 | 370 | &(pos)->member != NULL; \ |
6636f946 DG |
371 | cds_lfht_next(ht, iter), \ |
372 | pos = caa_container_of(cds_lfht_iter_get_node(iter), \ | |
373 | typeof(*(pos)), member)) | |
374 | ||
375 | #define cds_lfht_for_each_entry_duplicate(ht, match, hash, key, \ | |
376 | iter, pos, member) \ | |
377 | for (cds_lfht_lookup(ht, match, hash, key, iter), \ | |
378 | pos = caa_container_of(cds_lfht_iter_get_node(iter), \ | |
379 | typeof(*(pos)), member); \ | |
5450ed50 | 380 | &(pos)->member != NULL; \ |
6636f946 DG |
381 | cds_lfht_next_duplicate(ht, match, key, iter), \ |
382 | pos = caa_container_of(cds_lfht_iter_get_node(iter), \ | |
383 | typeof(*(pos)), member)) | |
384 | ||
fa68aa62 MD |
385 | #ifdef __cplusplus |
386 | } | |
387 | #endif | |
388 | ||
389 | #endif /* _URCU_RCULFHASH_H */ |