Commit | Line | Data |
---|---|---|
10544ee8 MD |
1 | #ifndef _LTTNG_UST_RCULFHASH_H |
2 | #define _LTTNG_UST_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 | * Copyright 2011 - Lai Jiangshan <laijs@cn.fujitsu.com> | |
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 | |
25 | */ | |
26 | ||
27 | #include <stdint.h> | |
28 | #include <pthread.h> | |
29 | #include <urcu/compiler.h> | |
30 | ||
31 | #ifdef __cplusplus | |
32 | extern "C" { | |
33 | #endif | |
34 | ||
35 | struct lttng_ust_lfht; | |
36 | ||
37 | /* | |
38 | * lttng_ust_lfht_node: Contains the next pointers and reverse-hash | |
39 | * value required for lookup and traversal of the hash table. | |
40 | * | |
41 | * struct lttng_ust_lfht_node should be aligned on 8-bytes boundaries because | |
42 | * the three lower bits are used as flags. It is worth noting that the | |
43 | * information contained within these three bits could be represented on | |
44 | * two bits by re-using the same bit for REMOVAL_OWNER_FLAG and | |
45 | * BUCKET_FLAG. This can be done if we ensure that no iterator nor | |
46 | * updater check the BUCKET_FLAG after it detects that the REMOVED_FLAG | |
47 | * is set. Given the minimum size of struct lttng_ust_lfht_node is 8 bytes on | |
48 | * 32-bit architectures, we choose to go for simplicity and reserve | |
49 | * three bits. | |
50 | * | |
51 | * struct lttng_ust_lfht_node can be embedded into a structure (as a field). | |
52 | * caa_container_of() can be used to get the structure from the struct | |
53 | * lttng_ust_lfht_node after a lookup. | |
54 | * | |
55 | * The structure which embeds it typically holds the key (or key-value | |
56 | * pair) of the object. The caller code is responsible for calculation | |
57 | * of the hash value for lttng_ust_lfht APIs. | |
58 | */ | |
59 | struct lttng_ust_lfht_node { | |
60 | struct lttng_ust_lfht_node *next; /* ptr | REMOVAL_OWNER_FLAG | BUCKET_FLAG | REMOVED_FLAG */ | |
61 | unsigned long reverse_hash; | |
62 | } __attribute__((aligned(8))); | |
63 | ||
64 | /* lttng_ust_lfht_iter: Used to track state while traversing a hash chain. */ | |
65 | struct lttng_ust_lfht_iter { | |
66 | struct lttng_ust_lfht_node *node, *next; | |
67 | }; | |
68 | ||
69 | static inline | |
70 | struct lttng_ust_lfht_node *lttng_ust_lfht_iter_get_node(struct lttng_ust_lfht_iter *iter) | |
71 | { | |
72 | return iter->node; | |
73 | } | |
74 | ||
75 | struct rcu_flavor_struct; | |
76 | ||
77 | /* | |
78 | * Caution ! | |
79 | * Ensure reader and writer threads are registered as urcu readers. | |
80 | */ | |
81 | ||
82 | typedef int (*lttng_ust_lfht_match_fct)(struct lttng_ust_lfht_node *node, const void *key); | |
83 | ||
84 | /* | |
85 | * lttng_ust_lfht_node_init - initialize a hash table node | |
86 | * @node: the node to initialize. | |
87 | * | |
88 | * This function is kept to be eventually used for debugging purposes | |
89 | * (detection of memory corruption). | |
90 | */ | |
91 | static inline | |
92 | void lttng_ust_lfht_node_init(struct lttng_ust_lfht_node *node) | |
93 | { | |
94 | } | |
95 | ||
96 | /* | |
97 | * Hash table creation flags. | |
98 | */ | |
99 | enum { | |
100 | LTTNG_UST_LFHT_AUTO_RESIZE = (1U << 0), | |
101 | LTTNG_UST_LFHT_ACCOUNTING = (1U << 1), | |
102 | }; | |
103 | ||
104 | struct lttng_ust_lfht_mm_type { | |
105 | struct lttng_ust_lfht *(*alloc_lttng_ust_lfht)(unsigned long min_nr_alloc_buckets, | |
106 | unsigned long max_nr_buckets); | |
107 | void (*alloc_bucket_table)(struct lttng_ust_lfht *ht, unsigned long order); | |
108 | void (*free_bucket_table)(struct lttng_ust_lfht *ht, unsigned long order); | |
109 | struct lttng_ust_lfht_node *(*bucket_at)(struct lttng_ust_lfht *ht, | |
110 | unsigned long index); | |
111 | }; | |
112 | ||
113 | extern const struct lttng_ust_lfht_mm_type lttng_ust_lfht_mm_order; | |
114 | extern const struct lttng_ust_lfht_mm_type lttng_ust_lfht_mm_chunk; | |
115 | extern const struct lttng_ust_lfht_mm_type lttng_ust_lfht_mm_mmap; | |
116 | ||
117 | /* | |
118 | * lttng_ust_lfht_new - allocate a hash table. | |
119 | * @init_size: number of buckets to allocate initially. Must be power of two. | |
120 | * @min_nr_alloc_buckets: the minimum number of allocated buckets. | |
121 | * (must be power of two) | |
122 | * @max_nr_buckets: the maximum number of hash table buckets allowed. | |
123 | * (must be power of two, 0 is accepted, means | |
124 | * "infinite") | |
125 | * @flags: hash table creation flags (can be combined with bitwise or: '|'). | |
126 | * 0: no flags. | |
127 | * LTTNG_UST_LFHT_AUTO_RESIZE: automatically resize hash table. | |
128 | * LTTNG_UST_LFHT_ACCOUNTING: count the number of node addition | |
129 | * and removal in the table | |
130 | * | |
131 | * Return NULL on error. | |
132 | * Note: the RCU flavor must be already included before the hash table header. | |
133 | */ | |
134 | extern | |
135 | struct lttng_ust_lfht *lttng_ust_lfht_new(unsigned long init_size, | |
136 | unsigned long min_nr_alloc_buckets, | |
137 | unsigned long max_nr_buckets, | |
138 | int flags, | |
139 | const struct lttng_ust_lfht_mm_type *mm); | |
140 | ||
141 | /* | |
142 | * lttng_ust_lfht_destroy - destroy a hash table. | |
143 | * @ht: the hash table to destroy. | |
144 | * | |
145 | * Return 0 on success, negative error value on error. | |
146 | ||
147 | * Prior to liburcu 0.10: | |
148 | * - Threads calling this API need to be registered RCU read-side | |
149 | * threads. | |
150 | * - lttng_ust_lfht_destroy should *not* be called from a RCU read-side | |
151 | * critical section. It should *not* be called from a call_rcu thread | |
152 | * context neither. | |
153 | * | |
154 | * Starting from liburcu 0.10, rculfhash implements its own worker | |
155 | * thread to handle resize operations, which removes RCU requirements on | |
156 | * lttng_ust_lfht_destroy. | |
157 | */ | |
158 | extern | |
159 | int lttng_ust_lfht_destroy(struct lttng_ust_lfht *ht); | |
160 | ||
161 | /* | |
162 | * lttng_ust_lfht_count_nodes - count the number of nodes in the hash table. | |
163 | * @ht: the hash table. | |
164 | * @split_count_before: sample the node count split-counter before traversal. | |
165 | * @count: traverse the hash table, count the number of nodes observed. | |
166 | * @split_count_after: sample the node count split-counter after traversal. | |
167 | * | |
168 | * Call with rcu_read_lock held. | |
169 | * Threads calling this API need to be registered RCU read-side threads. | |
170 | */ | |
171 | extern | |
172 | void lttng_ust_lfht_count_nodes(struct lttng_ust_lfht *ht, | |
173 | long *split_count_before, | |
174 | unsigned long *count, | |
175 | long *split_count_after); | |
176 | ||
177 | /* | |
178 | * lttng_ust_lfht_lookup - lookup a node by key. | |
179 | * @ht: the hash table. | |
180 | * @hash: the key hash. | |
181 | * @match: the key match function. | |
182 | * @key: the current node key. | |
183 | * @iter: node, if found (output). *iter->node set to NULL if not found. | |
184 | * | |
185 | * Call with rcu_read_lock held. | |
186 | * Threads calling this API need to be registered RCU read-side threads. | |
187 | * This function acts as a rcu_dereference() to read the node pointer. | |
188 | */ | |
189 | extern | |
190 | void lttng_ust_lfht_lookup(struct lttng_ust_lfht *ht, unsigned long hash, | |
191 | lttng_ust_lfht_match_fct match, const void *key, | |
192 | struct lttng_ust_lfht_iter *iter); | |
193 | ||
194 | /* | |
195 | * lttng_ust_lfht_next_duplicate - get the next item with same key, after iterator. | |
196 | * @ht: the hash table. | |
197 | * @match: the key match function. | |
198 | * @key: the current node key. | |
199 | * @iter: input: current iterator. | |
200 | * output: node, if found. *iter->node set to NULL if not found. | |
201 | * | |
202 | * Uses an iterator initialized by a lookup or traversal. Important: the | |
203 | * iterator _needs_ to be initialized before calling | |
204 | * lttng_ust_lfht_next_duplicate. | |
205 | * Sets *iter-node to the following node with same key. | |
206 | * Sets *iter->node to NULL if no following node exists with same key. | |
207 | * RCU read-side lock must be held across lttng_ust_lfht_lookup and | |
208 | * lttng_ust_lfht_next calls, and also between lttng_ust_lfht_next calls using the | |
209 | * node returned by a previous lttng_ust_lfht_next. | |
210 | * Call with rcu_read_lock held. | |
211 | * Threads calling this API need to be registered RCU read-side threads. | |
212 | * This function acts as a rcu_dereference() to read the node pointer. | |
213 | */ | |
214 | extern | |
215 | void lttng_ust_lfht_next_duplicate(struct lttng_ust_lfht *ht, | |
216 | lttng_ust_lfht_match_fct match, const void *key, | |
217 | struct lttng_ust_lfht_iter *iter); | |
218 | ||
219 | /* | |
220 | * lttng_ust_lfht_first - get the first node in the table. | |
221 | * @ht: the hash table. | |
222 | * @iter: First node, if exists (output). *iter->node set to NULL if not found. | |
223 | * | |
224 | * Output in "*iter". *iter->node set to NULL if table is empty. | |
225 | * Call with rcu_read_lock held. | |
226 | * Threads calling this API need to be registered RCU read-side threads. | |
227 | * This function acts as a rcu_dereference() to read the node pointer. | |
228 | */ | |
229 | extern | |
230 | void lttng_ust_lfht_first(struct lttng_ust_lfht *ht, struct lttng_ust_lfht_iter *iter); | |
231 | ||
232 | /* | |
233 | * lttng_ust_lfht_next - get the next node in the table. | |
234 | * @ht: the hash table. | |
235 | * @iter: input: current iterator. | |
236 | * output: next node, if exists. *iter->node set to NULL if not found. | |
237 | * | |
238 | * Input/Output in "*iter". *iter->node set to NULL if *iter was | |
239 | * pointing to the last table node. | |
240 | * Call with rcu_read_lock held. | |
241 | * Threads calling this API need to be registered RCU read-side threads. | |
242 | * This function acts as a rcu_dereference() to read the node pointer. | |
243 | */ | |
244 | extern | |
245 | void lttng_ust_lfht_next(struct lttng_ust_lfht *ht, struct lttng_ust_lfht_iter *iter); | |
246 | ||
247 | /* | |
248 | * lttng_ust_lfht_add - add a node to the hash table. | |
249 | * @ht: the hash table. | |
250 | * @hash: the key hash. | |
251 | * @node: the node to add. | |
252 | * | |
253 | * This function supports adding redundant keys into the table. | |
254 | * Call with rcu_read_lock held. | |
255 | * Threads calling this API need to be registered RCU read-side threads. | |
256 | * This function issues a full memory barrier before and after its | |
257 | * atomic commit. | |
258 | */ | |
259 | extern | |
260 | void lttng_ust_lfht_add(struct lttng_ust_lfht *ht, unsigned long hash, | |
261 | struct lttng_ust_lfht_node *node); | |
262 | ||
263 | /* | |
264 | * lttng_ust_lfht_add_unique - add a node to hash table, if key is not present. | |
265 | * @ht: the hash table. | |
266 | * @hash: the node's hash. | |
267 | * @match: the key match function. | |
268 | * @key: the node's key. | |
269 | * @node: the node to try adding. | |
270 | * | |
271 | * Return the node added upon success. | |
272 | * Return the unique node already present upon failure. If | |
273 | * lttng_ust_lfht_add_unique fails, the node passed as parameter should be | |
274 | * freed by the caller. In this case, the caller does NOT need to wait | |
275 | * for a grace period before freeing or re-using the node. | |
276 | * Call with rcu_read_lock held. | |
277 | * Threads calling this API need to be registered RCU read-side threads. | |
278 | * | |
279 | * The semantic of this function is that if only this function is used | |
280 | * to add keys into the table, no duplicated keys should ever be | |
281 | * observable in the table. The same guarantee apply for combination of | |
282 | * add_unique and add_replace (see below). | |
283 | * | |
284 | * Upon success, this function issues a full memory barrier before and | |
285 | * after its atomic commit. Upon failure, this function acts like a | |
286 | * simple lookup operation: it acts as a rcu_dereference() to read the | |
287 | * node pointer. The failure case does not guarantee any other memory | |
288 | * barrier. | |
289 | */ | |
290 | extern | |
291 | struct lttng_ust_lfht_node *lttng_ust_lfht_add_unique(struct lttng_ust_lfht *ht, | |
292 | unsigned long hash, | |
293 | lttng_ust_lfht_match_fct match, | |
294 | const void *key, | |
295 | struct lttng_ust_lfht_node *node); | |
296 | ||
297 | /* | |
298 | * lttng_ust_lfht_add_replace - replace or add a node within hash table. | |
299 | * @ht: the hash table. | |
300 | * @hash: the node's hash. | |
301 | * @match: the key match function. | |
302 | * @key: the node's key. | |
303 | * @node: the node to add. | |
304 | * | |
305 | * Return the node replaced upon success. If no node matching the key | |
306 | * was present, return NULL, which also means the operation succeeded. | |
307 | * This replacement operation should never fail. | |
308 | * Call with rcu_read_lock held. | |
309 | * Threads calling this API need to be registered RCU read-side threads. | |
310 | * After successful replacement, a grace period must be waited for before | |
311 | * freeing or re-using the memory reserved for the returned node. | |
312 | * | |
313 | * The semantic of replacement vs lookups and traversals is the | |
314 | * following: if lookups and traversals are performed between a key | |
315 | * unique insertion and its removal, we guarantee that the lookups and | |
316 | * traversals will always find exactly one instance of the key if it is | |
317 | * replaced concurrently with the lookups. | |
318 | * | |
319 | * Providing this semantic allows us to ensure that replacement-only | |
320 | * schemes will never generate duplicated keys. It also allows us to | |
321 | * guarantee that a combination of add_replace and add_unique updates | |
322 | * will never generate duplicated keys. | |
323 | * | |
324 | * This function issues a full memory barrier before and after its | |
325 | * atomic commit. | |
326 | */ | |
327 | extern | |
328 | struct lttng_ust_lfht_node *lttng_ust_lfht_add_replace(struct lttng_ust_lfht *ht, | |
329 | unsigned long hash, | |
330 | lttng_ust_lfht_match_fct match, | |
331 | const void *key, | |
332 | struct lttng_ust_lfht_node *node); | |
333 | ||
334 | /* | |
335 | * lttng_ust_lfht_replace - replace a node pointed to by iter within hash table. | |
336 | * @ht: the hash table. | |
337 | * @old_iter: the iterator position of the node to replace. | |
338 | * @hash: the node's hash. | |
339 | * @match: the key match function. | |
340 | * @key: the node's key. | |
341 | * @new_node: the new node to use as replacement. | |
342 | * | |
343 | * Return 0 if replacement is successful, negative value otherwise. | |
344 | * Replacing a NULL old node or an already removed node will fail with | |
345 | * -ENOENT. | |
346 | * If the hash or value of the node to replace and the new node differ, | |
347 | * this function returns -EINVAL without proceeding to the replacement. | |
348 | * Old node can be looked up with lttng_ust_lfht_lookup and lttng_ust_lfht_next. | |
349 | * RCU read-side lock must be held between lookup and replacement. | |
350 | * Call with rcu_read_lock held. | |
351 | * Threads calling this API need to be registered RCU read-side threads. | |
352 | * After successful replacement, a grace period must be waited for before | |
353 | * freeing or re-using the memory reserved for the old node (which can | |
354 | * be accessed with lttng_ust_lfht_iter_get_node). | |
355 | * | |
356 | * The semantic of replacement vs lookups is the same as | |
357 | * lttng_ust_lfht_add_replace(). | |
358 | * | |
359 | * Upon success, this function issues a full memory barrier before and | |
360 | * after its atomic commit. Upon failure, this function does not issue | |
361 | * any memory barrier. | |
362 | */ | |
363 | extern | |
364 | int lttng_ust_lfht_replace(struct lttng_ust_lfht *ht, | |
365 | struct lttng_ust_lfht_iter *old_iter, | |
366 | unsigned long hash, | |
367 | lttng_ust_lfht_match_fct match, | |
368 | const void *key, | |
369 | struct lttng_ust_lfht_node *new_node); | |
370 | ||
371 | /* | |
372 | * lttng_ust_lfht_del - remove node pointed to by iterator from hash table. | |
373 | * @ht: the hash table. | |
374 | * @node: the node to delete. | |
375 | * | |
376 | * Return 0 if the node is successfully removed, negative value | |
377 | * otherwise. | |
378 | * Deleting a NULL node or an already removed node will fail with a | |
379 | * negative value. | |
380 | * Node can be looked up with lttng_ust_lfht_lookup and lttng_ust_lfht_next, | |
381 | * followed by use of lttng_ust_lfht_iter_get_node. | |
382 | * RCU read-side lock must be held between lookup and removal. | |
383 | * Call with rcu_read_lock held. | |
384 | * Threads calling this API need to be registered RCU read-side threads. | |
385 | * After successful removal, a grace period must be waited for before | |
386 | * freeing or re-using the memory reserved for old node (which can be | |
387 | * accessed with lttng_ust_lfht_iter_get_node). | |
388 | * Upon success, this function issues a full memory barrier before and | |
389 | * after its atomic commit. Upon failure, this function does not issue | |
390 | * any memory barrier. | |
391 | */ | |
392 | extern | |
393 | int lttng_ust_lfht_del(struct lttng_ust_lfht *ht, struct lttng_ust_lfht_node *node); | |
394 | ||
395 | /* | |
396 | * lttng_ust_lfht_is_node_deleted - query whether a node is removed from hash table. | |
397 | * | |
398 | * Return non-zero if the node is deleted from the hash table, 0 | |
399 | * otherwise. | |
400 | * Node can be looked up with lttng_ust_lfht_lookup and lttng_ust_lfht_next, | |
401 | * followed by use of lttng_ust_lfht_iter_get_node. | |
402 | * RCU read-side lock must be held between lookup and call to this | |
403 | * function. | |
404 | * Call with rcu_read_lock held. | |
405 | * Threads calling this API need to be registered RCU read-side threads. | |
406 | * This function does not issue any memory barrier. | |
407 | */ | |
408 | extern | |
409 | int lttng_ust_lfht_is_node_deleted(const struct lttng_ust_lfht_node *node); | |
410 | ||
411 | /* | |
412 | * lttng_ust_lfht_resize - Force a hash table resize | |
413 | * @ht: the hash table. | |
414 | * @new_size: update to this hash table size. | |
415 | * | |
416 | * Threads calling this API need to be registered RCU read-side threads. | |
417 | * This function does not (necessarily) issue memory barriers. | |
418 | * lttng_ust_lfht_resize should *not* be called from a RCU read-side critical | |
419 | * section. | |
420 | */ | |
421 | extern | |
422 | void lttng_ust_lfht_resize(struct lttng_ust_lfht *ht, unsigned long new_size); | |
423 | ||
424 | /* | |
425 | * Note: it is safe to perform element removal (del), replacement, or | |
426 | * any hash table update operation during any of the following hash | |
427 | * table traversals. | |
428 | * These functions act as rcu_dereference() to read the node pointers. | |
429 | */ | |
430 | #define lttng_ust_lfht_for_each(ht, iter, node) \ | |
431 | for (lttng_ust_lfht_first(ht, iter), \ | |
432 | node = lttng_ust_lfht_iter_get_node(iter); \ | |
433 | node != NULL; \ | |
434 | lttng_ust_lfht_next(ht, iter), \ | |
435 | node = lttng_ust_lfht_iter_get_node(iter)) | |
436 | ||
437 | #define lttng_ust_lfht_for_each_duplicate(ht, hash, match, key, iter, node) \ | |
438 | for (lttng_ust_lfht_lookup(ht, hash, match, key, iter), \ | |
439 | node = lttng_ust_lfht_iter_get_node(iter); \ | |
440 | node != NULL; \ | |
441 | lttng_ust_lfht_next_duplicate(ht, match, key, iter), \ | |
442 | node = lttng_ust_lfht_iter_get_node(iter)) | |
443 | ||
444 | #define lttng_ust_lfht_for_each_entry(ht, iter, pos, member) \ | |
445 | for (lttng_ust_lfht_first(ht, iter), \ | |
446 | pos = caa_container_of(lttng_ust_lfht_iter_get_node(iter), \ | |
447 | __typeof__(*(pos)), member); \ | |
448 | lttng_ust_lfht_iter_get_node(iter) != NULL; \ | |
449 | lttng_ust_lfht_next(ht, iter), \ | |
450 | pos = caa_container_of(lttng_ust_lfht_iter_get_node(iter), \ | |
451 | __typeof__(*(pos)), member)) | |
452 | ||
453 | #define lttng_ust_lfht_for_each_entry_duplicate(ht, hash, match, key, \ | |
454 | iter, pos, member) \ | |
455 | for (lttng_ust_lfht_lookup(ht, hash, match, key, iter), \ | |
456 | pos = caa_container_of(lttng_ust_lfht_iter_get_node(iter), \ | |
457 | __typeof__(*(pos)), member); \ | |
458 | lttng_ust_lfht_iter_get_node(iter) != NULL; \ | |
459 | lttng_ust_lfht_next_duplicate(ht, match, key, iter), \ | |
460 | pos = caa_container_of(lttng_ust_lfht_iter_get_node(iter), \ | |
461 | __typeof__(*(pos)), member)) | |
462 | ||
463 | #ifdef __cplusplus | |
464 | } | |
465 | #endif | |
466 | ||
467 | #endif /* _LTTNG_UST_RCULFHASH_H */ |