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5e28c532 | 1 | /* |
abc490a1 MD |
2 | * rculfhash.c |
3 | * | |
1475579c | 4 | * Userspace RCU library - Lock-Free Resizable RCU Hash Table |
abc490a1 MD |
5 | * |
6 | * Copyright 2010-2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
0dcf4847 | 7 | * Copyright 2011 - Lai Jiangshan <laijs@cn.fujitsu.com> |
abc490a1 MD |
8 | * |
9 | * This library is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU Lesser General Public | |
11 | * License as published by the Free Software Foundation; either | |
12 | * version 2.1 of the License, or (at your option) any later version. | |
13 | * | |
14 | * This library is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | * Lesser General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU Lesser General Public | |
20 | * License along with this library; if not, write to the Free Software | |
21 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
5e28c532 MD |
22 | */ |
23 | ||
e753ff5a MD |
24 | /* |
25 | * Based on the following articles: | |
26 | * - Ori Shalev and Nir Shavit. Split-ordered lists: Lock-free | |
27 | * extensible hash tables. J. ACM 53, 3 (May 2006), 379-405. | |
28 | * - Michael, M. M. High performance dynamic lock-free hash tables | |
29 | * and list-based sets. In Proceedings of the fourteenth annual ACM | |
30 | * symposium on Parallel algorithms and architectures, ACM Press, | |
31 | * (2002), 73-82. | |
32 | * | |
1475579c | 33 | * Some specificities of this Lock-Free Resizable RCU Hash Table |
e753ff5a MD |
34 | * implementation: |
35 | * | |
36 | * - RCU read-side critical section allows readers to perform hash | |
1f67ba50 MD |
37 | * table lookups, as well as traversals, and use the returned objects |
38 | * safely by allowing memory reclaim to take place only after a grace | |
39 | * period. | |
e753ff5a MD |
40 | * - Add and remove operations are lock-free, and do not need to |
41 | * allocate memory. They need to be executed within RCU read-side | |
42 | * critical section to ensure the objects they read are valid and to | |
43 | * deal with the cmpxchg ABA problem. | |
44 | * - add and add_unique operations are supported. add_unique checks if | |
1f67ba50 MD |
45 | * the node key already exists in the hash table. It ensures not to |
46 | * populate a duplicate key if the node key already exists in the hash | |
47 | * table. | |
48 | * - The resize operation executes concurrently with | |
49 | * add/add_unique/add_replace/remove/lookup/traversal. | |
e753ff5a MD |
50 | * - Hash table nodes are contained within a split-ordered list. This |
51 | * list is ordered by incrementing reversed-bits-hash value. | |
1ee8f000 | 52 | * - An index of bucket nodes is kept. These bucket nodes are the hash |
1f67ba50 MD |
53 | * table "buckets". These buckets are internal nodes that allow to |
54 | * perform a fast hash lookup, similarly to a skip list. These | |
55 | * buckets are chained together in the split-ordered list, which | |
56 | * allows recursive expansion by inserting new buckets between the | |
57 | * existing buckets. The split-ordered list allows adding new buckets | |
58 | * between existing buckets as the table needs to grow. | |
59 | * - The resize operation for small tables only allows expanding the | |
60 | * hash table. It is triggered automatically by detecting long chains | |
61 | * in the add operation. | |
1475579c MD |
62 | * - The resize operation for larger tables (and available through an |
63 | * API) allows both expanding and shrinking the hash table. | |
4c42f1b8 | 64 | * - Split-counters are used to keep track of the number of |
1475579c | 65 | * nodes within the hash table for automatic resize triggering. |
e753ff5a | 66 | * - Resize operation initiated by long chain detection is executed by a |
d0ec0ed2 | 67 | * worker thread, which keeps lock-freedom of add and remove. |
e753ff5a MD |
68 | * - Resize operations are protected by a mutex. |
69 | * - The removal operation is split in two parts: first, a "removed" | |
70 | * flag is set in the next pointer within the node to remove. Then, | |
71 | * a "garbage collection" is performed in the bucket containing the | |
72 | * removed node (from the start of the bucket up to the removed node). | |
73 | * All encountered nodes with "removed" flag set in their next | |
74 | * pointers are removed from the linked-list. If the cmpxchg used for | |
75 | * removal fails (due to concurrent garbage-collection or concurrent | |
76 | * add), we retry from the beginning of the bucket. This ensures that | |
77 | * the node with "removed" flag set is removed from the hash table | |
78 | * (not visible to lookups anymore) before the RCU read-side critical | |
79 | * section held across removal ends. Furthermore, this ensures that | |
80 | * the node with "removed" flag set is removed from the linked-list | |
5c4ca589 MD |
81 | * before its memory is reclaimed. After setting the "removal" flag, |
82 | * only the thread which removal is the first to set the "removal | |
83 | * owner" flag (with an xchg) into a node's next pointer is considered | |
84 | * to have succeeded its removal (and thus owns the node to reclaim). | |
85 | * Because we garbage-collect starting from an invariant node (the | |
86 | * start-of-bucket bucket node) up to the "removed" node (or find a | |
87 | * reverse-hash that is higher), we are sure that a successful | |
88 | * traversal of the chain leads to a chain that is present in the | |
1f67ba50 | 89 | * linked-list (the start node is never removed) and that it does not |
5c4ca589 MD |
90 | * contain the "removed" node anymore, even if concurrent delete/add |
91 | * operations are changing the structure of the list concurrently. | |
1f67ba50 MD |
92 | * - The add operations perform garbage collection of buckets if they |
93 | * encounter nodes with removed flag set in the bucket where they want | |
94 | * to add their new node. This ensures lock-freedom of add operation by | |
29e669f6 MD |
95 | * helping the remover unlink nodes from the list rather than to wait |
96 | * for it do to so. | |
1f67ba50 MD |
97 | * - There are three memory backends for the hash table buckets: the |
98 | * "order table", the "chunks", and the "mmap". | |
99 | * - These bucket containers contain a compact version of the hash table | |
100 | * nodes. | |
101 | * - The RCU "order table": | |
102 | * - has a first level table indexed by log2(hash index) which is | |
103 | * copied and expanded by the resize operation. This order table | |
104 | * allows finding the "bucket node" tables. | |
105 | * - There is one bucket node table per hash index order. The size of | |
106 | * each bucket node table is half the number of hashes contained in | |
107 | * this order (except for order 0). | |
108 | * - The RCU "chunks" is best suited for close interaction with a page | |
109 | * allocator. It uses a linear array as index to "chunks" containing | |
110 | * each the same number of buckets. | |
111 | * - The RCU "mmap" memory backend uses a single memory map to hold | |
112 | * all buckets. | |
5f177b1c | 113 | * - synchronize_rcu is used to garbage-collect the old bucket node table. |
93d46c39 | 114 | * |
7f949215 | 115 | * Ordering Guarantees: |
0f5543cb | 116 | * |
7f949215 MD |
117 | * To discuss these guarantees, we first define "read" operation as any |
118 | * of the the basic cds_lfht_lookup, cds_lfht_next_duplicate, | |
119 | * cds_lfht_first, cds_lfht_next operation, as well as | |
67ecffc0 | 120 | * cds_lfht_add_unique (failure). |
7f949215 MD |
121 | * |
122 | * We define "read traversal" operation as any of the following | |
123 | * group of operations | |
0f5543cb | 124 | * - cds_lfht_lookup followed by iteration with cds_lfht_next_duplicate |
7f949215 MD |
125 | * (and/or cds_lfht_next, although less common). |
126 | * - cds_lfht_add_unique (failure) followed by iteration with | |
127 | * cds_lfht_next_duplicate (and/or cds_lfht_next, although less | |
128 | * common). | |
129 | * - cds_lfht_first followed iteration with cds_lfht_next (and/or | |
130 | * cds_lfht_next_duplicate, although less common). | |
0f5543cb | 131 | * |
bf09adc7 | 132 | * We define "write" operations as any of cds_lfht_add, cds_lfht_replace, |
7f949215 MD |
133 | * cds_lfht_add_unique (success), cds_lfht_add_replace, cds_lfht_del. |
134 | * | |
135 | * When cds_lfht_add_unique succeeds (returns the node passed as | |
136 | * parameter), it acts as a "write" operation. When cds_lfht_add_unique | |
137 | * fails (returns a node different from the one passed as parameter), it | |
138 | * acts as a "read" operation. A cds_lfht_add_unique failure is a | |
139 | * cds_lfht_lookup "read" operation, therefore, any ordering guarantee | |
140 | * referring to "lookup" imply any of "lookup" or cds_lfht_add_unique | |
141 | * (failure). | |
142 | * | |
143 | * We define "prior" and "later" node as nodes observable by reads and | |
144 | * read traversals respectively before and after a write or sequence of | |
145 | * write operations. | |
146 | * | |
147 | * Hash-table operations are often cascaded, for example, the pointer | |
148 | * returned by a cds_lfht_lookup() might be passed to a cds_lfht_next(), | |
149 | * whose return value might in turn be passed to another hash-table | |
150 | * operation. This entire cascaded series of operations must be enclosed | |
151 | * by a pair of matching rcu_read_lock() and rcu_read_unlock() | |
152 | * operations. | |
153 | * | |
154 | * The following ordering guarantees are offered by this hash table: | |
155 | * | |
156 | * A.1) "read" after "write": if there is ordering between a write and a | |
157 | * later read, then the read is guaranteed to see the write or some | |
158 | * later write. | |
159 | * A.2) "read traversal" after "write": given that there is dependency | |
160 | * ordering between reads in a "read traversal", if there is | |
161 | * ordering between a write and the first read of the traversal, | |
162 | * then the "read traversal" is guaranteed to see the write or | |
163 | * some later write. | |
164 | * B.1) "write" after "read": if there is ordering between a read and a | |
165 | * later write, then the read will never see the write. | |
166 | * B.2) "write" after "read traversal": given that there is dependency | |
167 | * ordering between reads in a "read traversal", if there is | |
168 | * ordering between the last read of the traversal and a later | |
169 | * write, then the "read traversal" will never see the write. | |
170 | * C) "write" while "read traversal": if a write occurs during a "read | |
171 | * traversal", the traversal may, or may not, see the write. | |
172 | * D.1) "write" after "write": if there is ordering between a write and | |
173 | * a later write, then the later write is guaranteed to see the | |
174 | * effects of the first write. | |
175 | * D.2) Concurrent "write" pairs: The system will assign an arbitrary | |
176 | * order to any pair of concurrent conflicting writes. | |
177 | * Non-conflicting writes (for example, to different keys) are | |
178 | * unordered. | |
179 | * E) If a grace period separates a "del" or "replace" operation | |
180 | * and a subsequent operation, then that subsequent operation is | |
181 | * guaranteed not to see the removed item. | |
182 | * F) Uniqueness guarantee: given a hash table that does not contain | |
183 | * duplicate items for a given key, there will only be one item in | |
184 | * the hash table after an arbitrary sequence of add_unique and/or | |
185 | * add_replace operations. Note, however, that a pair of | |
186 | * concurrent read operations might well access two different items | |
187 | * with that key. | |
188 | * G.1) If a pair of lookups for a given key are ordered (e.g. by a | |
189 | * memory barrier), then the second lookup will return the same | |
190 | * node as the previous lookup, or some later node. | |
191 | * G.2) A "read traversal" that starts after the end of a prior "read | |
192 | * traversal" (ordered by memory barriers) is guaranteed to see the | |
193 | * same nodes as the previous traversal, or some later nodes. | |
194 | * G.3) Concurrent "read" pairs: concurrent reads are unordered. For | |
195 | * example, if a pair of reads to the same key run concurrently | |
196 | * with an insertion of that same key, the reads remain unordered | |
197 | * regardless of their return values. In other words, you cannot | |
198 | * rely on the values returned by the reads to deduce ordering. | |
199 | * | |
200 | * Progress guarantees: | |
201 | * | |
202 | * * Reads are wait-free. These operations always move forward in the | |
203 | * hash table linked list, and this list has no loop. | |
204 | * * Writes are lock-free. Any retry loop performed by a write operation | |
205 | * is triggered by progress made within another update operation. | |
0f5543cb | 206 | * |
1ee8f000 | 207 | * Bucket node tables: |
93d46c39 | 208 | * |
1ee8f000 LJ |
209 | * hash table hash table the last all bucket node tables |
210 | * order size bucket node 0 1 2 3 4 5 6(index) | |
93d46c39 LJ |
211 | * table size |
212 | * 0 1 1 1 | |
213 | * 1 2 1 1 1 | |
214 | * 2 4 2 1 1 2 | |
215 | * 3 8 4 1 1 2 4 | |
216 | * 4 16 8 1 1 2 4 8 | |
217 | * 5 32 16 1 1 2 4 8 16 | |
218 | * 6 64 32 1 1 2 4 8 16 32 | |
219 | * | |
1ee8f000 | 220 | * When growing/shrinking, we only focus on the last bucket node table |
93d46c39 LJ |
221 | * which size is (!order ? 1 : (1 << (order -1))). |
222 | * | |
223 | * Example for growing/shrinking: | |
1ee8f000 LJ |
224 | * grow hash table from order 5 to 6: init the index=6 bucket node table |
225 | * shrink hash table from order 6 to 5: fini the index=6 bucket node table | |
93d46c39 | 226 | * |
1475579c | 227 | * A bit of ascii art explanation: |
67ecffc0 | 228 | * |
1f67ba50 MD |
229 | * The order index is the off-by-one compared to the actual power of 2 |
230 | * because we use index 0 to deal with the 0 special-case. | |
67ecffc0 | 231 | * |
1475579c | 232 | * This shows the nodes for a small table ordered by reversed bits: |
67ecffc0 | 233 | * |
1475579c MD |
234 | * bits reverse |
235 | * 0 000 000 | |
236 | * 4 100 001 | |
237 | * 2 010 010 | |
238 | * 6 110 011 | |
239 | * 1 001 100 | |
240 | * 5 101 101 | |
241 | * 3 011 110 | |
242 | * 7 111 111 | |
67ecffc0 MD |
243 | * |
244 | * This shows the nodes in order of non-reversed bits, linked by | |
1475579c | 245 | * reversed-bit order. |
67ecffc0 | 246 | * |
1475579c MD |
247 | * order bits reverse |
248 | * 0 0 000 000 | |
0adc36a8 LJ |
249 | * 1 | 1 001 100 <- |
250 | * 2 | | 2 010 010 <- | | |
f6fdd688 | 251 | * | | | 3 011 110 | <- | |
1475579c MD |
252 | * 3 -> | | | 4 100 001 | | |
253 | * -> | | 5 101 101 | | |
254 | * -> | 6 110 011 | |
255 | * -> 7 111 111 | |
e753ff5a MD |
256 | */ |
257 | ||
2ed95849 MD |
258 | #define _LGPL_SOURCE |
259 | #include <stdlib.h> | |
e0ba718a | 260 | #include <errno.h> |
e0ba718a | 261 | #include <stdio.h> |
abc490a1 | 262 | #include <stdint.h> |
f000907d | 263 | #include <string.h> |
125f41db | 264 | #include <sched.h> |
95747f9e | 265 | #include <unistd.h> |
e0ba718a | 266 | |
a47dd11c | 267 | #include "compat-getcpu.h" |
01477510 | 268 | #include <urcu/assert.h> |
6cd23d47 MD |
269 | #include <urcu/pointer.h> |
270 | #include <urcu/call-rcu.h> | |
271 | #include <urcu/flavor.h> | |
a42cc659 MD |
272 | #include <urcu/arch.h> |
273 | #include <urcu/uatomic.h> | |
a42cc659 | 274 | #include <urcu/compiler.h> |
abc490a1 | 275 | #include <urcu/rculfhash.h> |
1a990de3 | 276 | #include <urcu/static/urcu-signal-nr.h> |
0b6aa001 | 277 | #include <rculfhash-internal.h> |
5e28c532 | 278 | #include <stdio.h> |
464a1ec9 | 279 | #include <pthread.h> |
d0ec0ed2 MD |
280 | #include <signal.h> |
281 | #include "workqueue.h" | |
282 | #include "urcu-die.h" | |
83e334d0 | 283 | #include "urcu-utils.h" |
44395fb7 | 284 | |
f8994aee | 285 | /* |
4c42f1b8 | 286 | * Split-counters lazily update the global counter each 1024 |
f8994aee MD |
287 | * addition/removal. It automatically keeps track of resize required. |
288 | * We use the bucket length as indicator for need to expand for small | |
ffa11a18 | 289 | * tables and machines lacking per-cpu data support. |
f8994aee MD |
290 | */ |
291 | #define COUNT_COMMIT_ORDER 10 | |
4ddbb355 | 292 | #define DEFAULT_SPLIT_COUNT_MASK 0xFUL |
6ea6bc67 MD |
293 | #define CHAIN_LEN_TARGET 1 |
294 | #define CHAIN_LEN_RESIZE_THRESHOLD 3 | |
2ed95849 | 295 | |
cd95516d | 296 | /* |
76a73da8 | 297 | * Define the minimum table size. |
cd95516d | 298 | */ |
d0d8f9aa LJ |
299 | #define MIN_TABLE_ORDER 0 |
300 | #define MIN_TABLE_SIZE (1UL << MIN_TABLE_ORDER) | |
cd95516d | 301 | |
b7d619b0 | 302 | /* |
1ee8f000 | 303 | * Minimum number of bucket nodes to touch per thread to parallelize grow/shrink. |
b7d619b0 | 304 | */ |
6083a889 MD |
305 | #define MIN_PARTITION_PER_THREAD_ORDER 12 |
306 | #define MIN_PARTITION_PER_THREAD (1UL << MIN_PARTITION_PER_THREAD_ORDER) | |
b7d619b0 | 307 | |
d95bd160 MD |
308 | /* |
309 | * The removed flag needs to be updated atomically with the pointer. | |
48ed1c18 | 310 | * It indicates that no node must attach to the node scheduled for |
b198f0fd | 311 | * removal, and that node garbage collection must be performed. |
1ee8f000 | 312 | * The bucket flag does not require to be updated atomically with the |
d95bd160 | 313 | * pointer, but it is added as a pointer low bit flag to save space. |
1f67ba50 MD |
314 | * The "removal owner" flag is used to detect which of the "del" |
315 | * operation that has set the "removed flag" gets to return the removed | |
316 | * node to its caller. Note that the replace operation does not need to | |
317 | * iteract with the "removal owner" flag, because it validates that | |
318 | * the "removed" flag is not set before performing its cmpxchg. | |
d95bd160 | 319 | */ |
d37166c6 | 320 | #define REMOVED_FLAG (1UL << 0) |
1ee8f000 | 321 | #define BUCKET_FLAG (1UL << 1) |
db00ccc3 MD |
322 | #define REMOVAL_OWNER_FLAG (1UL << 2) |
323 | #define FLAGS_MASK ((1UL << 3) - 1) | |
d37166c6 | 324 | |
bb7b2f26 | 325 | /* Value of the end pointer. Should not interact with flags. */ |
f9c80341 | 326 | #define END_VALUE NULL |
bb7b2f26 | 327 | |
7f52427b MD |
328 | /* |
329 | * ht_items_count: Split-counters counting the number of node addition | |
330 | * and removal in the table. Only used if the CDS_LFHT_ACCOUNTING flag | |
331 | * is set at hash table creation. | |
332 | * | |
333 | * These are free-running counters, never reset to zero. They count the | |
334 | * number of add/remove, and trigger every (1 << COUNT_COMMIT_ORDER) | |
335 | * operations to update the global counter. We choose a power-of-2 value | |
336 | * for the trigger to deal with 32 or 64-bit overflow of the counter. | |
337 | */ | |
df44348d | 338 | struct ht_items_count { |
860d07e8 | 339 | unsigned long add, del; |
df44348d MD |
340 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
341 | ||
7f52427b | 342 | /* |
d0ec0ed2 | 343 | * resize_work: Contains arguments passed to worker thread |
7f52427b MD |
344 | * responsible for performing lazy resize. |
345 | */ | |
d0ec0ed2 MD |
346 | struct resize_work { |
347 | struct urcu_work work; | |
14044b37 | 348 | struct cds_lfht *ht; |
abc490a1 | 349 | }; |
2ed95849 | 350 | |
7f52427b MD |
351 | /* |
352 | * partition_resize_work: Contains arguments passed to worker threads | |
353 | * executing the hash table resize on partitions of the hash table | |
354 | * assigned to each processor's worker thread. | |
355 | */ | |
b7d619b0 | 356 | struct partition_resize_work { |
1af6e26e | 357 | pthread_t thread_id; |
b7d619b0 MD |
358 | struct cds_lfht *ht; |
359 | unsigned long i, start, len; | |
360 | void (*fct)(struct cds_lfht *ht, unsigned long i, | |
361 | unsigned long start, unsigned long len); | |
362 | }; | |
363 | ||
d0ec0ed2 MD |
364 | static struct urcu_workqueue *cds_lfht_workqueue; |
365 | static unsigned long cds_lfht_workqueue_user_count; | |
366 | ||
367 | /* | |
368 | * Mutex ensuring mutual exclusion between workqueue initialization and | |
369 | * fork handlers. cds_lfht_fork_mutex nests inside call_rcu_mutex. | |
370 | */ | |
371 | static pthread_mutex_t cds_lfht_fork_mutex = PTHREAD_MUTEX_INITIALIZER; | |
372 | ||
373 | static struct urcu_atfork cds_lfht_atfork; | |
374 | ||
375 | /* | |
376 | * atfork handler nesting counters. Handle being registered to many urcu | |
377 | * flavors, thus being possibly invoked more than once in the | |
378 | * pthread_atfork list of callbacks. | |
379 | */ | |
380 | static int cds_lfht_workqueue_atfork_nesting; | |
381 | ||
382 | static void cds_lfht_init_worker(const struct rcu_flavor_struct *flavor); | |
383 | static void cds_lfht_fini_worker(const struct rcu_flavor_struct *flavor); | |
384 | ||
d7c76f85 MD |
385 | #ifdef CONFIG_CDS_LFHT_ITER_DEBUG |
386 | ||
387 | static | |
388 | void cds_lfht_iter_debug_set_ht(struct cds_lfht *ht, struct cds_lfht_iter *iter) | |
389 | { | |
390 | iter->lfht = ht; | |
391 | } | |
392 | ||
01477510 | 393 | #define cds_lfht_iter_debug_assert(...) urcu_posix_assert(__VA_ARGS__) |
d7c76f85 MD |
394 | |
395 | #else | |
396 | ||
397 | static | |
70469b43 MJ |
398 | void cds_lfht_iter_debug_set_ht(struct cds_lfht *ht __attribute__((unused)), |
399 | struct cds_lfht_iter *iter __attribute__((unused))) | |
d7c76f85 MD |
400 | { |
401 | } | |
402 | ||
403 | #define cds_lfht_iter_debug_assert(...) | |
404 | ||
405 | #endif | |
406 | ||
abc490a1 MD |
407 | /* |
408 | * Algorithm to reverse bits in a word by lookup table, extended to | |
409 | * 64-bit words. | |
f9830efd | 410 | * Source: |
abc490a1 | 411 | * http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable |
f9830efd | 412 | * Originally from Public Domain. |
abc490a1 MD |
413 | */ |
414 | ||
67ecffc0 | 415 | static const uint8_t BitReverseTable256[256] = |
2ed95849 | 416 | { |
abc490a1 MD |
417 | #define R2(n) (n), (n) + 2*64, (n) + 1*64, (n) + 3*64 |
418 | #define R4(n) R2(n), R2((n) + 2*16), R2((n) + 1*16), R2((n) + 3*16) | |
419 | #define R6(n) R4(n), R4((n) + 2*4 ), R4((n) + 1*4 ), R4((n) + 3*4 ) | |
420 | R6(0), R6(2), R6(1), R6(3) | |
421 | }; | |
422 | #undef R2 | |
423 | #undef R4 | |
424 | #undef R6 | |
2ed95849 | 425 | |
abc490a1 MD |
426 | static |
427 | uint8_t bit_reverse_u8(uint8_t v) | |
428 | { | |
429 | return BitReverseTable256[v]; | |
430 | } | |
ab7d5fc6 | 431 | |
95bc7fb9 MD |
432 | #if (CAA_BITS_PER_LONG == 32) |
433 | static | |
abc490a1 MD |
434 | uint32_t bit_reverse_u32(uint32_t v) |
435 | { | |
67ecffc0 MD |
436 | return ((uint32_t) bit_reverse_u8(v) << 24) | |
437 | ((uint32_t) bit_reverse_u8(v >> 8) << 16) | | |
438 | ((uint32_t) bit_reverse_u8(v >> 16) << 8) | | |
abc490a1 | 439 | ((uint32_t) bit_reverse_u8(v >> 24)); |
2ed95849 | 440 | } |
95bc7fb9 MD |
441 | #else |
442 | static | |
abc490a1 | 443 | uint64_t bit_reverse_u64(uint64_t v) |
2ed95849 | 444 | { |
67ecffc0 MD |
445 | return ((uint64_t) bit_reverse_u8(v) << 56) | |
446 | ((uint64_t) bit_reverse_u8(v >> 8) << 48) | | |
abc490a1 MD |
447 | ((uint64_t) bit_reverse_u8(v >> 16) << 40) | |
448 | ((uint64_t) bit_reverse_u8(v >> 24) << 32) | | |
67ecffc0 MD |
449 | ((uint64_t) bit_reverse_u8(v >> 32) << 24) | |
450 | ((uint64_t) bit_reverse_u8(v >> 40) << 16) | | |
abc490a1 MD |
451 | ((uint64_t) bit_reverse_u8(v >> 48) << 8) | |
452 | ((uint64_t) bit_reverse_u8(v >> 56)); | |
453 | } | |
95bc7fb9 | 454 | #endif |
abc490a1 MD |
455 | |
456 | static | |
457 | unsigned long bit_reverse_ulong(unsigned long v) | |
458 | { | |
459 | #if (CAA_BITS_PER_LONG == 32) | |
460 | return bit_reverse_u32(v); | |
461 | #else | |
462 | return bit_reverse_u64(v); | |
463 | #endif | |
464 | } | |
465 | ||
f9830efd | 466 | /* |
24365af7 MD |
467 | * fls: returns the position of the most significant bit. |
468 | * Returns 0 if no bit is set, else returns the position of the most | |
469 | * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit). | |
f9830efd | 470 | */ |
0b1e236d | 471 | #if defined(URCU_ARCH_X86) |
24365af7 MD |
472 | static inline |
473 | unsigned int fls_u32(uint32_t x) | |
f9830efd | 474 | { |
24365af7 MD |
475 | int r; |
476 | ||
e1789ce2 | 477 | __asm__ ("bsrl %1,%0\n\t" |
24365af7 MD |
478 | "jnz 1f\n\t" |
479 | "movl $-1,%0\n\t" | |
480 | "1:\n\t" | |
481 | : "=r" (r) : "rm" (x)); | |
482 | return r + 1; | |
483 | } | |
484 | #define HAS_FLS_U32 | |
485 | #endif | |
486 | ||
0b1e236d | 487 | #if defined(URCU_ARCH_AMD64) |
24365af7 MD |
488 | static inline |
489 | unsigned int fls_u64(uint64_t x) | |
490 | { | |
491 | long r; | |
492 | ||
e1789ce2 | 493 | __asm__ ("bsrq %1,%0\n\t" |
24365af7 MD |
494 | "jnz 1f\n\t" |
495 | "movq $-1,%0\n\t" | |
496 | "1:\n\t" | |
497 | : "=r" (r) : "rm" (x)); | |
498 | return r + 1; | |
499 | } | |
500 | #define HAS_FLS_U64 | |
501 | #endif | |
502 | ||
503 | #ifndef HAS_FLS_U64 | |
504 | static __attribute__((unused)) | |
505 | unsigned int fls_u64(uint64_t x) | |
506 | { | |
507 | unsigned int r = 64; | |
508 | ||
509 | if (!x) | |
510 | return 0; | |
511 | ||
512 | if (!(x & 0xFFFFFFFF00000000ULL)) { | |
513 | x <<= 32; | |
514 | r -= 32; | |
515 | } | |
516 | if (!(x & 0xFFFF000000000000ULL)) { | |
517 | x <<= 16; | |
518 | r -= 16; | |
519 | } | |
520 | if (!(x & 0xFF00000000000000ULL)) { | |
521 | x <<= 8; | |
522 | r -= 8; | |
523 | } | |
524 | if (!(x & 0xF000000000000000ULL)) { | |
525 | x <<= 4; | |
526 | r -= 4; | |
527 | } | |
528 | if (!(x & 0xC000000000000000ULL)) { | |
529 | x <<= 2; | |
530 | r -= 2; | |
531 | } | |
532 | if (!(x & 0x8000000000000000ULL)) { | |
533 | x <<= 1; | |
534 | r -= 1; | |
535 | } | |
536 | return r; | |
537 | } | |
538 | #endif | |
539 | ||
540 | #ifndef HAS_FLS_U32 | |
541 | static __attribute__((unused)) | |
542 | unsigned int fls_u32(uint32_t x) | |
543 | { | |
544 | unsigned int r = 32; | |
f9830efd | 545 | |
24365af7 MD |
546 | if (!x) |
547 | return 0; | |
548 | if (!(x & 0xFFFF0000U)) { | |
549 | x <<= 16; | |
550 | r -= 16; | |
551 | } | |
552 | if (!(x & 0xFF000000U)) { | |
553 | x <<= 8; | |
554 | r -= 8; | |
555 | } | |
556 | if (!(x & 0xF0000000U)) { | |
557 | x <<= 4; | |
558 | r -= 4; | |
559 | } | |
560 | if (!(x & 0xC0000000U)) { | |
561 | x <<= 2; | |
562 | r -= 2; | |
563 | } | |
564 | if (!(x & 0x80000000U)) { | |
565 | x <<= 1; | |
566 | r -= 1; | |
567 | } | |
568 | return r; | |
569 | } | |
570 | #endif | |
571 | ||
5bc6b66f | 572 | unsigned int cds_lfht_fls_ulong(unsigned long x) |
f9830efd | 573 | { |
6887cc5e | 574 | #if (CAA_BITS_PER_LONG == 32) |
24365af7 MD |
575 | return fls_u32(x); |
576 | #else | |
577 | return fls_u64(x); | |
578 | #endif | |
579 | } | |
f9830efd | 580 | |
920f8ef6 LJ |
581 | /* |
582 | * Return the minimum order for which x <= (1UL << order). | |
583 | * Return -1 if x is 0. | |
584 | */ | |
61c3fb60 | 585 | static |
5bc6b66f | 586 | int cds_lfht_get_count_order_u32(uint32_t x) |
24365af7 | 587 | { |
920f8ef6 LJ |
588 | if (!x) |
589 | return -1; | |
24365af7 | 590 | |
920f8ef6 | 591 | return fls_u32(x - 1); |
24365af7 MD |
592 | } |
593 | ||
920f8ef6 LJ |
594 | /* |
595 | * Return the minimum order for which x <= (1UL << order). | |
596 | * Return -1 if x is 0. | |
597 | */ | |
5bc6b66f | 598 | int cds_lfht_get_count_order_ulong(unsigned long x) |
24365af7 | 599 | { |
920f8ef6 LJ |
600 | if (!x) |
601 | return -1; | |
24365af7 | 602 | |
5bc6b66f | 603 | return cds_lfht_fls_ulong(x - 1); |
f9830efd MD |
604 | } |
605 | ||
606 | static | |
ab65b890 | 607 | void cds_lfht_resize_lazy_grow(struct cds_lfht *ht, unsigned long size, int growth); |
f9830efd | 608 | |
f8994aee | 609 | static |
4105056a | 610 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, |
f8994aee MD |
611 | unsigned long count); |
612 | ||
5ffcaeef MD |
613 | static void mutex_lock(pthread_mutex_t *mutex) |
614 | { | |
615 | int ret; | |
616 | ||
617 | #ifndef DISTRUST_SIGNALS_EXTREME | |
618 | ret = pthread_mutex_lock(mutex); | |
619 | if (ret) | |
620 | urcu_die(ret); | |
621 | #else /* #ifndef DISTRUST_SIGNALS_EXTREME */ | |
622 | while ((ret = pthread_mutex_trylock(mutex)) != 0) { | |
623 | if (ret != EBUSY && ret != EINTR) | |
624 | urcu_die(ret); | |
625 | if (CMM_LOAD_SHARED(URCU_TLS(rcu_reader).need_mb)) { | |
626 | cmm_smp_mb(); | |
627 | _CMM_STORE_SHARED(URCU_TLS(rcu_reader).need_mb, 0); | |
628 | cmm_smp_mb(); | |
629 | } | |
630 | (void) poll(NULL, 0, 10); | |
631 | } | |
632 | #endif /* #else #ifndef DISTRUST_SIGNALS_EXTREME */ | |
633 | } | |
634 | ||
635 | static void mutex_unlock(pthread_mutex_t *mutex) | |
636 | { | |
637 | int ret; | |
638 | ||
639 | ret = pthread_mutex_unlock(mutex); | |
640 | if (ret) | |
641 | urcu_die(ret); | |
642 | } | |
643 | ||
df44348d | 644 | static long nr_cpus_mask = -1; |
4c42f1b8 | 645 | static long split_count_mask = -1; |
e53ab1eb | 646 | static int split_count_order = -1; |
4c42f1b8 | 647 | |
4ddbb355 | 648 | #if defined(HAVE_SYSCONF) |
4c42f1b8 LJ |
649 | static void ht_init_nr_cpus_mask(void) |
650 | { | |
651 | long maxcpus; | |
652 | ||
653 | maxcpus = sysconf(_SC_NPROCESSORS_CONF); | |
654 | if (maxcpus <= 0) { | |
655 | nr_cpus_mask = -2; | |
656 | return; | |
657 | } | |
658 | /* | |
659 | * round up number of CPUs to next power of two, so we | |
660 | * can use & for modulo. | |
661 | */ | |
5bc6b66f | 662 | maxcpus = 1UL << cds_lfht_get_count_order_ulong(maxcpus); |
4c42f1b8 LJ |
663 | nr_cpus_mask = maxcpus - 1; |
664 | } | |
4ddbb355 LJ |
665 | #else /* #if defined(HAVE_SYSCONF) */ |
666 | static void ht_init_nr_cpus_mask(void) | |
667 | { | |
668 | nr_cpus_mask = -2; | |
669 | } | |
670 | #endif /* #else #if defined(HAVE_SYSCONF) */ | |
df44348d MD |
671 | |
672 | static | |
5afadd12 | 673 | void alloc_split_items_count(struct cds_lfht *ht) |
df44348d | 674 | { |
4c42f1b8 LJ |
675 | if (nr_cpus_mask == -1) { |
676 | ht_init_nr_cpus_mask(); | |
4ddbb355 LJ |
677 | if (nr_cpus_mask < 0) |
678 | split_count_mask = DEFAULT_SPLIT_COUNT_MASK; | |
679 | else | |
680 | split_count_mask = nr_cpus_mask; | |
e53ab1eb MD |
681 | split_count_order = |
682 | cds_lfht_get_count_order_ulong(split_count_mask + 1); | |
df44348d | 683 | } |
4c42f1b8 | 684 | |
01477510 | 685 | urcu_posix_assert(split_count_mask >= 0); |
5afadd12 LJ |
686 | |
687 | if (ht->flags & CDS_LFHT_ACCOUNTING) { | |
95bc7fb9 MD |
688 | ht->split_count = calloc(split_count_mask + 1, |
689 | sizeof(struct ht_items_count)); | |
01477510 | 690 | urcu_posix_assert(ht->split_count); |
5afadd12 LJ |
691 | } else { |
692 | ht->split_count = NULL; | |
693 | } | |
df44348d MD |
694 | } |
695 | ||
696 | static | |
5afadd12 | 697 | void free_split_items_count(struct cds_lfht *ht) |
df44348d | 698 | { |
5afadd12 | 699 | poison_free(ht->split_count); |
df44348d MD |
700 | } |
701 | ||
702 | static | |
14360f1c | 703 | int ht_get_split_count_index(unsigned long hash) |
df44348d MD |
704 | { |
705 | int cpu; | |
706 | ||
01477510 | 707 | urcu_posix_assert(split_count_mask >= 0); |
a47dd11c | 708 | cpu = urcu_sched_getcpu(); |
8ed51e04 | 709 | if (caa_unlikely(cpu < 0)) |
14360f1c | 710 | return hash & split_count_mask; |
df44348d | 711 | else |
4c42f1b8 | 712 | return cpu & split_count_mask; |
df44348d MD |
713 | } |
714 | ||
715 | static | |
14360f1c | 716 | void ht_count_add(struct cds_lfht *ht, unsigned long size, unsigned long hash) |
df44348d | 717 | { |
83e334d0 | 718 | unsigned long split_count, count; |
4c42f1b8 | 719 | int index; |
df44348d | 720 | |
8ed51e04 | 721 | if (caa_unlikely(!ht->split_count)) |
3171717f | 722 | return; |
14360f1c | 723 | index = ht_get_split_count_index(hash); |
4c42f1b8 | 724 | split_count = uatomic_add_return(&ht->split_count[index].add, 1); |
314558bf MD |
725 | if (caa_likely(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1))) |
726 | return; | |
727 | /* Only if number of add multiple of 1UL << COUNT_COMMIT_ORDER */ | |
728 | ||
729 | dbg_printf("add split count %lu\n", split_count); | |
730 | count = uatomic_add_return(&ht->count, | |
731 | 1UL << COUNT_COMMIT_ORDER); | |
4c299dcb | 732 | if (caa_likely(count & (count - 1))) |
314558bf MD |
733 | return; |
734 | /* Only if global count is power of 2 */ | |
735 | ||
736 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) < size) | |
737 | return; | |
83e334d0 | 738 | dbg_printf("add set global %lu\n", count); |
314558bf MD |
739 | cds_lfht_resize_lazy_count(ht, size, |
740 | count >> (CHAIN_LEN_TARGET - 1)); | |
df44348d MD |
741 | } |
742 | ||
743 | static | |
14360f1c | 744 | void ht_count_del(struct cds_lfht *ht, unsigned long size, unsigned long hash) |
df44348d | 745 | { |
83e334d0 | 746 | unsigned long split_count, count; |
4c42f1b8 | 747 | int index; |
df44348d | 748 | |
8ed51e04 | 749 | if (caa_unlikely(!ht->split_count)) |
3171717f | 750 | return; |
14360f1c | 751 | index = ht_get_split_count_index(hash); |
4c42f1b8 | 752 | split_count = uatomic_add_return(&ht->split_count[index].del, 1); |
314558bf MD |
753 | if (caa_likely(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1))) |
754 | return; | |
755 | /* Only if number of deletes multiple of 1UL << COUNT_COMMIT_ORDER */ | |
756 | ||
757 | dbg_printf("del split count %lu\n", split_count); | |
758 | count = uatomic_add_return(&ht->count, | |
759 | -(1UL << COUNT_COMMIT_ORDER)); | |
4c299dcb | 760 | if (caa_likely(count & (count - 1))) |
314558bf MD |
761 | return; |
762 | /* Only if global count is power of 2 */ | |
763 | ||
764 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) >= size) | |
765 | return; | |
766 | dbg_printf("del set global %ld\n", count); | |
767 | /* | |
768 | * Don't shrink table if the number of nodes is below a | |
769 | * certain threshold. | |
770 | */ | |
771 | if (count < (1UL << COUNT_COMMIT_ORDER) * (split_count_mask + 1)) | |
772 | return; | |
773 | cds_lfht_resize_lazy_count(ht, size, | |
774 | count >> (CHAIN_LEN_TARGET - 1)); | |
df44348d MD |
775 | } |
776 | ||
f9830efd | 777 | static |
4105056a | 778 | void check_resize(struct cds_lfht *ht, unsigned long size, uint32_t chain_len) |
f9830efd | 779 | { |
f8994aee MD |
780 | unsigned long count; |
781 | ||
b8af5011 MD |
782 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) |
783 | return; | |
f8994aee MD |
784 | count = uatomic_read(&ht->count); |
785 | /* | |
786 | * Use bucket-local length for small table expand and for | |
787 | * environments lacking per-cpu data support. | |
788 | */ | |
e53ab1eb | 789 | if (count >= (1UL << (COUNT_COMMIT_ORDER + split_count_order))) |
f8994aee | 790 | return; |
24365af7 | 791 | if (chain_len > 100) |
f0c29ed7 | 792 | dbg_printf("WARNING: large chain length: %u.\n", |
24365af7 | 793 | chain_len); |
e53ab1eb MD |
794 | if (chain_len >= CHAIN_LEN_RESIZE_THRESHOLD) { |
795 | int growth; | |
796 | ||
797 | /* | |
798 | * Ideal growth calculated based on chain length. | |
799 | */ | |
800 | growth = cds_lfht_get_count_order_u32(chain_len | |
801 | - (CHAIN_LEN_TARGET - 1)); | |
802 | if ((ht->flags & CDS_LFHT_ACCOUNTING) | |
803 | && (size << growth) | |
804 | >= (1UL << (COUNT_COMMIT_ORDER | |
805 | + split_count_order))) { | |
806 | /* | |
807 | * If ideal growth expands the hash table size | |
808 | * beyond the "small hash table" sizes, use the | |
809 | * maximum small hash table size to attempt | |
810 | * expanding the hash table. This only applies | |
811 | * when node accounting is available, otherwise | |
812 | * the chain length is used to expand the hash | |
813 | * table in every case. | |
814 | */ | |
815 | growth = COUNT_COMMIT_ORDER + split_count_order | |
816 | - cds_lfht_get_count_order_ulong(size); | |
817 | if (growth <= 0) | |
818 | return; | |
819 | } | |
820 | cds_lfht_resize_lazy_grow(ht, size, growth); | |
821 | } | |
f9830efd MD |
822 | } |
823 | ||
abc490a1 | 824 | static |
14044b37 | 825 | struct cds_lfht_node *clear_flag(struct cds_lfht_node *node) |
abc490a1 | 826 | { |
14044b37 | 827 | return (struct cds_lfht_node *) (((unsigned long) node) & ~FLAGS_MASK); |
abc490a1 MD |
828 | } |
829 | ||
830 | static | |
afa5940d | 831 | int is_removed(const struct cds_lfht_node *node) |
abc490a1 | 832 | { |
d37166c6 | 833 | return ((unsigned long) node) & REMOVED_FLAG; |
abc490a1 MD |
834 | } |
835 | ||
f5596c94 | 836 | static |
1ee8f000 | 837 | int is_bucket(struct cds_lfht_node *node) |
f5596c94 | 838 | { |
1ee8f000 | 839 | return ((unsigned long) node) & BUCKET_FLAG; |
f5596c94 MD |
840 | } |
841 | ||
842 | static | |
1ee8f000 | 843 | struct cds_lfht_node *flag_bucket(struct cds_lfht_node *node) |
f5596c94 | 844 | { |
1ee8f000 | 845 | return (struct cds_lfht_node *) (((unsigned long) node) | BUCKET_FLAG); |
f5596c94 | 846 | } |
bb7b2f26 | 847 | |
db00ccc3 MD |
848 | static |
849 | int is_removal_owner(struct cds_lfht_node *node) | |
850 | { | |
851 | return ((unsigned long) node) & REMOVAL_OWNER_FLAG; | |
852 | } | |
853 | ||
854 | static | |
855 | struct cds_lfht_node *flag_removal_owner(struct cds_lfht_node *node) | |
856 | { | |
857 | return (struct cds_lfht_node *) (((unsigned long) node) | REMOVAL_OWNER_FLAG); | |
858 | } | |
859 | ||
71bb3aca MD |
860 | static |
861 | struct cds_lfht_node *flag_removed_or_removal_owner(struct cds_lfht_node *node) | |
862 | { | |
863 | return (struct cds_lfht_node *) (((unsigned long) node) | REMOVED_FLAG | REMOVAL_OWNER_FLAG); | |
864 | } | |
865 | ||
bb7b2f26 MD |
866 | static |
867 | struct cds_lfht_node *get_end(void) | |
868 | { | |
869 | return (struct cds_lfht_node *) END_VALUE; | |
870 | } | |
871 | ||
872 | static | |
873 | int is_end(struct cds_lfht_node *node) | |
874 | { | |
875 | return clear_flag(node) == (struct cds_lfht_node *) END_VALUE; | |
876 | } | |
877 | ||
abc490a1 | 878 | static |
ab65b890 LJ |
879 | unsigned long _uatomic_xchg_monotonic_increase(unsigned long *ptr, |
880 | unsigned long v) | |
abc490a1 MD |
881 | { |
882 | unsigned long old1, old2; | |
883 | ||
884 | old1 = uatomic_read(ptr); | |
885 | do { | |
886 | old2 = old1; | |
887 | if (old2 >= v) | |
f9830efd | 888 | return old2; |
abc490a1 | 889 | } while ((old1 = uatomic_cmpxchg(ptr, old2, v)) != old2); |
ab65b890 | 890 | return old2; |
abc490a1 MD |
891 | } |
892 | ||
48f1b16d LJ |
893 | static |
894 | void cds_lfht_alloc_bucket_table(struct cds_lfht *ht, unsigned long order) | |
895 | { | |
0b6aa001 | 896 | return ht->mm->alloc_bucket_table(ht, order); |
48f1b16d LJ |
897 | } |
898 | ||
899 | /* | |
900 | * cds_lfht_free_bucket_table() should be called with decreasing order. | |
901 | * When cds_lfht_free_bucket_table(0) is called, it means the whole | |
902 | * lfht is destroyed. | |
903 | */ | |
904 | static | |
905 | void cds_lfht_free_bucket_table(struct cds_lfht *ht, unsigned long order) | |
906 | { | |
0b6aa001 | 907 | return ht->mm->free_bucket_table(ht, order); |
48f1b16d LJ |
908 | } |
909 | ||
9d72a73f LJ |
910 | static inline |
911 | struct cds_lfht_node *bucket_at(struct cds_lfht *ht, unsigned long index) | |
f4a9cc0b | 912 | { |
0b6aa001 | 913 | return ht->bucket_at(ht, index); |
f4a9cc0b LJ |
914 | } |
915 | ||
9d72a73f LJ |
916 | static inline |
917 | struct cds_lfht_node *lookup_bucket(struct cds_lfht *ht, unsigned long size, | |
918 | unsigned long hash) | |
919 | { | |
01477510 | 920 | urcu_posix_assert(size > 0); |
9d72a73f LJ |
921 | return bucket_at(ht, hash & (size - 1)); |
922 | } | |
923 | ||
273399de MD |
924 | /* |
925 | * Remove all logically deleted nodes from a bucket up to a certain node key. | |
926 | */ | |
927 | static | |
1ee8f000 | 928 | void _cds_lfht_gc_bucket(struct cds_lfht_node *bucket, struct cds_lfht_node *node) |
273399de | 929 | { |
14044b37 | 930 | struct cds_lfht_node *iter_prev, *iter, *next, *new_next; |
273399de | 931 | |
01477510 FD |
932 | urcu_posix_assert(!is_bucket(bucket)); |
933 | urcu_posix_assert(!is_removed(bucket)); | |
934 | urcu_posix_assert(!is_removal_owner(bucket)); | |
935 | urcu_posix_assert(!is_bucket(node)); | |
936 | urcu_posix_assert(!is_removed(node)); | |
937 | urcu_posix_assert(!is_removal_owner(node)); | |
273399de | 938 | for (;;) { |
1ee8f000 LJ |
939 | iter_prev = bucket; |
940 | /* We can always skip the bucket node initially */ | |
04db56f8 | 941 | iter = rcu_dereference(iter_prev->next); |
01477510 FD |
942 | urcu_posix_assert(!is_removed(iter)); |
943 | urcu_posix_assert(!is_removal_owner(iter)); | |
944 | urcu_posix_assert(iter_prev->reverse_hash <= node->reverse_hash); | |
bd4db153 | 945 | /* |
1ee8f000 | 946 | * We should never be called with bucket (start of chain) |
bd4db153 MD |
947 | * and logically removed node (end of path compression |
948 | * marker) being the actual same node. This would be a | |
949 | * bug in the algorithm implementation. | |
950 | */ | |
01477510 | 951 | urcu_posix_assert(bucket != node); |
273399de | 952 | for (;;) { |
8ed51e04 | 953 | if (caa_unlikely(is_end(iter))) |
f9c80341 | 954 | return; |
04db56f8 | 955 | if (caa_likely(clear_flag(iter)->reverse_hash > node->reverse_hash)) |
f9c80341 | 956 | return; |
04db56f8 | 957 | next = rcu_dereference(clear_flag(iter)->next); |
8ed51e04 | 958 | if (caa_likely(is_removed(next))) |
273399de | 959 | break; |
b453eae1 | 960 | iter_prev = clear_flag(iter); |
273399de MD |
961 | iter = next; |
962 | } | |
01477510 FD |
963 | urcu_posix_assert(!is_removed(iter)); |
964 | urcu_posix_assert(!is_removal_owner(iter)); | |
1ee8f000 LJ |
965 | if (is_bucket(iter)) |
966 | new_next = flag_bucket(clear_flag(next)); | |
f5596c94 MD |
967 | else |
968 | new_next = clear_flag(next); | |
04db56f8 | 969 | (void) uatomic_cmpxchg(&iter_prev->next, iter, new_next); |
273399de MD |
970 | } |
971 | } | |
972 | ||
9357c415 MD |
973 | static |
974 | int _cds_lfht_replace(struct cds_lfht *ht, unsigned long size, | |
975 | struct cds_lfht_node *old_node, | |
3fb86f26 | 976 | struct cds_lfht_node *old_next, |
9357c415 MD |
977 | struct cds_lfht_node *new_node) |
978 | { | |
04db56f8 | 979 | struct cds_lfht_node *bucket, *ret_next; |
9357c415 MD |
980 | |
981 | if (!old_node) /* Return -ENOENT if asked to replace NULL node */ | |
7801dadd | 982 | return -ENOENT; |
9357c415 | 983 | |
01477510 FD |
984 | urcu_posix_assert(!is_removed(old_node)); |
985 | urcu_posix_assert(!is_removal_owner(old_node)); | |
986 | urcu_posix_assert(!is_bucket(old_node)); | |
987 | urcu_posix_assert(!is_removed(new_node)); | |
988 | urcu_posix_assert(!is_removal_owner(new_node)); | |
989 | urcu_posix_assert(!is_bucket(new_node)); | |
990 | urcu_posix_assert(new_node != old_node); | |
3fb86f26 | 991 | for (;;) { |
9357c415 | 992 | /* Insert after node to be replaced */ |
9357c415 MD |
993 | if (is_removed(old_next)) { |
994 | /* | |
995 | * Too late, the old node has been removed under us | |
996 | * between lookup and replace. Fail. | |
997 | */ | |
7801dadd | 998 | return -ENOENT; |
9357c415 | 999 | } |
01477510 FD |
1000 | urcu_posix_assert(old_next == clear_flag(old_next)); |
1001 | urcu_posix_assert(new_node != old_next); | |
71bb3aca MD |
1002 | /* |
1003 | * REMOVAL_OWNER flag is _NEVER_ set before the REMOVED | |
1004 | * flag. It is either set atomically at the same time | |
1005 | * (replace) or after (del). | |
1006 | */ | |
01477510 | 1007 | urcu_posix_assert(!is_removal_owner(old_next)); |
feda2722 | 1008 | new_node->next = old_next; |
9357c415 MD |
1009 | /* |
1010 | * Here is the whole trick for lock-free replace: we add | |
1011 | * the replacement node _after_ the node we want to | |
1012 | * replace by atomically setting its next pointer at the | |
1013 | * same time we set its removal flag. Given that | |
1014 | * the lookups/get next use an iterator aware of the | |
1015 | * next pointer, they will either skip the old node due | |
1016 | * to the removal flag and see the new node, or use | |
1017 | * the old node, but will not see the new one. | |
db00ccc3 MD |
1018 | * This is a replacement of a node with another node |
1019 | * that has the same value: we are therefore not | |
71bb3aca MD |
1020 | * removing a value from the hash table. We set both the |
1021 | * REMOVED and REMOVAL_OWNER flags atomically so we own | |
1022 | * the node after successful cmpxchg. | |
9357c415 | 1023 | */ |
04db56f8 | 1024 | ret_next = uatomic_cmpxchg(&old_node->next, |
71bb3aca | 1025 | old_next, flag_removed_or_removal_owner(new_node)); |
3fb86f26 | 1026 | if (ret_next == old_next) |
7801dadd | 1027 | break; /* We performed the replacement. */ |
3fb86f26 LJ |
1028 | old_next = ret_next; |
1029 | } | |
9357c415 | 1030 | |
9357c415 MD |
1031 | /* |
1032 | * Ensure that the old node is not visible to readers anymore: | |
1033 | * lookup for the node, and remove it (along with any other | |
1034 | * logically removed node) if found. | |
1035 | */ | |
04db56f8 LJ |
1036 | bucket = lookup_bucket(ht, size, bit_reverse_ulong(old_node->reverse_hash)); |
1037 | _cds_lfht_gc_bucket(bucket, new_node); | |
7801dadd | 1038 | |
01477510 | 1039 | urcu_posix_assert(is_removed(CMM_LOAD_SHARED(old_node->next))); |
7801dadd | 1040 | return 0; |
9357c415 MD |
1041 | } |
1042 | ||
83beee94 MD |
1043 | /* |
1044 | * A non-NULL unique_ret pointer uses the "add unique" (or uniquify) add | |
1045 | * mode. A NULL unique_ret allows creation of duplicate keys. | |
1046 | */ | |
abc490a1 | 1047 | static |
83beee94 | 1048 | void _cds_lfht_add(struct cds_lfht *ht, |
91a75cc5 | 1049 | unsigned long hash, |
0422d92c | 1050 | cds_lfht_match_fct match, |
996ff57c | 1051 | const void *key, |
83beee94 MD |
1052 | unsigned long size, |
1053 | struct cds_lfht_node *node, | |
1054 | struct cds_lfht_iter *unique_ret, | |
1ee8f000 | 1055 | int bucket_flag) |
abc490a1 | 1056 | { |
14044b37 | 1057 | struct cds_lfht_node *iter_prev, *iter, *next, *new_node, *new_next, |
960c9e4f | 1058 | *return_node; |
04db56f8 | 1059 | struct cds_lfht_node *bucket; |
abc490a1 | 1060 | |
01477510 FD |
1061 | urcu_posix_assert(!is_bucket(node)); |
1062 | urcu_posix_assert(!is_removed(node)); | |
1063 | urcu_posix_assert(!is_removal_owner(node)); | |
91a75cc5 | 1064 | bucket = lookup_bucket(ht, size, hash); |
abc490a1 | 1065 | for (;;) { |
adc0de68 | 1066 | uint32_t chain_len = 0; |
abc490a1 | 1067 | |
11519af6 MD |
1068 | /* |
1069 | * iter_prev points to the non-removed node prior to the | |
1070 | * insert location. | |
11519af6 | 1071 | */ |
04db56f8 | 1072 | iter_prev = bucket; |
1ee8f000 | 1073 | /* We can always skip the bucket node initially */ |
04db56f8 | 1074 | iter = rcu_dereference(iter_prev->next); |
01477510 | 1075 | urcu_posix_assert(iter_prev->reverse_hash <= node->reverse_hash); |
abc490a1 | 1076 | for (;;) { |
8ed51e04 | 1077 | if (caa_unlikely(is_end(iter))) |
273399de | 1078 | goto insert; |
04db56f8 | 1079 | if (caa_likely(clear_flag(iter)->reverse_hash > node->reverse_hash)) |
273399de | 1080 | goto insert; |
238cc06e | 1081 | |
1ee8f000 LJ |
1082 | /* bucket node is the first node of the identical-hash-value chain */ |
1083 | if (bucket_flag && clear_flag(iter)->reverse_hash == node->reverse_hash) | |
194fdbd1 | 1084 | goto insert; |
238cc06e | 1085 | |
04db56f8 | 1086 | next = rcu_dereference(clear_flag(iter)->next); |
8ed51e04 | 1087 | if (caa_unlikely(is_removed(next))) |
9dba85be | 1088 | goto gc_node; |
238cc06e LJ |
1089 | |
1090 | /* uniquely add */ | |
83beee94 | 1091 | if (unique_ret |
1ee8f000 | 1092 | && !is_bucket(next) |
04db56f8 | 1093 | && clear_flag(iter)->reverse_hash == node->reverse_hash) { |
d7c76f85 MD |
1094 | struct cds_lfht_iter d_iter = { |
1095 | .node = node, | |
1096 | .next = iter, | |
1097 | #ifdef CONFIG_CDS_LFHT_ITER_DEBUG | |
1098 | .lfht = ht, | |
1099 | #endif | |
1100 | }; | |
238cc06e LJ |
1101 | |
1102 | /* | |
1103 | * uniquely adding inserts the node as the first | |
1104 | * node of the identical-hash-value node chain. | |
1105 | * | |
1106 | * This semantic ensures no duplicated keys | |
1107 | * should ever be observable in the table | |
1f67ba50 MD |
1108 | * (including traversing the table node by |
1109 | * node by forward iterations) | |
238cc06e | 1110 | */ |
04db56f8 | 1111 | cds_lfht_next_duplicate(ht, match, key, &d_iter); |
238cc06e LJ |
1112 | if (!d_iter.node) |
1113 | goto insert; | |
1114 | ||
1115 | *unique_ret = d_iter; | |
83beee94 | 1116 | return; |
48ed1c18 | 1117 | } |
238cc06e | 1118 | |
11519af6 | 1119 | /* Only account for identical reverse hash once */ |
04db56f8 | 1120 | if (iter_prev->reverse_hash != clear_flag(iter)->reverse_hash |
1ee8f000 | 1121 | && !is_bucket(next)) |
4105056a | 1122 | check_resize(ht, size, ++chain_len); |
11519af6 | 1123 | iter_prev = clear_flag(iter); |
273399de | 1124 | iter = next; |
abc490a1 | 1125 | } |
48ed1c18 | 1126 | |
273399de | 1127 | insert: |
01477510 FD |
1128 | urcu_posix_assert(node != clear_flag(iter)); |
1129 | urcu_posix_assert(!is_removed(iter_prev)); | |
1130 | urcu_posix_assert(!is_removal_owner(iter_prev)); | |
1131 | urcu_posix_assert(!is_removed(iter)); | |
1132 | urcu_posix_assert(!is_removal_owner(iter)); | |
1133 | urcu_posix_assert(iter_prev != node); | |
1ee8f000 | 1134 | if (!bucket_flag) |
04db56f8 | 1135 | node->next = clear_flag(iter); |
f9c80341 | 1136 | else |
1ee8f000 LJ |
1137 | node->next = flag_bucket(clear_flag(iter)); |
1138 | if (is_bucket(iter)) | |
1139 | new_node = flag_bucket(node); | |
f5596c94 MD |
1140 | else |
1141 | new_node = node; | |
04db56f8 | 1142 | if (uatomic_cmpxchg(&iter_prev->next, iter, |
48ed1c18 | 1143 | new_node) != iter) { |
273399de | 1144 | continue; /* retry */ |
48ed1c18 | 1145 | } else { |
83beee94 | 1146 | return_node = node; |
960c9e4f | 1147 | goto end; |
48ed1c18 MD |
1148 | } |
1149 | ||
9dba85be | 1150 | gc_node: |
01477510 FD |
1151 | urcu_posix_assert(!is_removed(iter)); |
1152 | urcu_posix_assert(!is_removal_owner(iter)); | |
1ee8f000 LJ |
1153 | if (is_bucket(iter)) |
1154 | new_next = flag_bucket(clear_flag(next)); | |
f5596c94 MD |
1155 | else |
1156 | new_next = clear_flag(next); | |
04db56f8 | 1157 | (void) uatomic_cmpxchg(&iter_prev->next, iter, new_next); |
273399de | 1158 | /* retry */ |
464a1ec9 | 1159 | } |
9357c415 | 1160 | end: |
83beee94 MD |
1161 | if (unique_ret) { |
1162 | unique_ret->node = return_node; | |
1163 | /* unique_ret->next left unset, never used. */ | |
1164 | } | |
abc490a1 | 1165 | } |
464a1ec9 | 1166 | |
abc490a1 | 1167 | static |
860d07e8 | 1168 | int _cds_lfht_del(struct cds_lfht *ht, unsigned long size, |
b65ec430 | 1169 | struct cds_lfht_node *node) |
abc490a1 | 1170 | { |
db00ccc3 | 1171 | struct cds_lfht_node *bucket, *next; |
5e28c532 | 1172 | |
9357c415 | 1173 | if (!node) /* Return -ENOENT if asked to delete NULL node */ |
743f9143 | 1174 | return -ENOENT; |
9357c415 | 1175 | |
7ec59d3b | 1176 | /* logically delete the node */ |
01477510 FD |
1177 | urcu_posix_assert(!is_bucket(node)); |
1178 | urcu_posix_assert(!is_removed(node)); | |
1179 | urcu_posix_assert(!is_removal_owner(node)); | |
48ed1c18 | 1180 | |
db00ccc3 MD |
1181 | /* |
1182 | * We are first checking if the node had previously been | |
1183 | * logically removed (this check is not atomic with setting the | |
1184 | * logical removal flag). Return -ENOENT if the node had | |
1185 | * previously been removed. | |
1186 | */ | |
a85eff52 | 1187 | next = CMM_LOAD_SHARED(node->next); /* next is not dereferenced */ |
db00ccc3 MD |
1188 | if (caa_unlikely(is_removed(next))) |
1189 | return -ENOENT; | |
01477510 | 1190 | urcu_posix_assert(!is_bucket(next)); |
196f4fab MD |
1191 | /* |
1192 | * The del operation semantic guarantees a full memory barrier | |
1193 | * before the uatomic_or atomic commit of the deletion flag. | |
1194 | */ | |
1195 | cmm_smp_mb__before_uatomic_or(); | |
db00ccc3 MD |
1196 | /* |
1197 | * We set the REMOVED_FLAG unconditionally. Note that there may | |
1198 | * be more than one concurrent thread setting this flag. | |
1199 | * Knowing which wins the race will be known after the garbage | |
1200 | * collection phase, stay tuned! | |
1201 | */ | |
1202 | uatomic_or(&node->next, REMOVED_FLAG); | |
7ec59d3b | 1203 | /* We performed the (logical) deletion. */ |
7ec59d3b MD |
1204 | |
1205 | /* | |
1206 | * Ensure that the node is not visible to readers anymore: lookup for | |
273399de MD |
1207 | * the node, and remove it (along with any other logically removed node) |
1208 | * if found. | |
11519af6 | 1209 | */ |
04db56f8 LJ |
1210 | bucket = lookup_bucket(ht, size, bit_reverse_ulong(node->reverse_hash)); |
1211 | _cds_lfht_gc_bucket(bucket, node); | |
743f9143 | 1212 | |
01477510 | 1213 | urcu_posix_assert(is_removed(CMM_LOAD_SHARED(node->next))); |
db00ccc3 MD |
1214 | /* |
1215 | * Last phase: atomically exchange node->next with a version | |
1216 | * having "REMOVAL_OWNER_FLAG" set. If the returned node->next | |
1217 | * pointer did _not_ have "REMOVAL_OWNER_FLAG" set, we now own | |
1218 | * the node and win the removal race. | |
1219 | * It is interesting to note that all "add" paths are forbidden | |
1220 | * to change the next pointer starting from the point where the | |
1221 | * REMOVED_FLAG is set, so here using a read, followed by a | |
1222 | * xchg() suffice to guarantee that the xchg() will ever only | |
1223 | * set the "REMOVAL_OWNER_FLAG" (or change nothing if the flag | |
1224 | * was already set). | |
1225 | */ | |
1226 | if (!is_removal_owner(uatomic_xchg(&node->next, | |
1227 | flag_removal_owner(node->next)))) | |
1228 | return 0; | |
1229 | else | |
1230 | return -ENOENT; | |
abc490a1 | 1231 | } |
2ed95849 | 1232 | |
b7d619b0 MD |
1233 | static |
1234 | void *partition_resize_thread(void *arg) | |
1235 | { | |
1236 | struct partition_resize_work *work = arg; | |
1237 | ||
7b17c13e | 1238 | work->ht->flavor->register_thread(); |
b7d619b0 | 1239 | work->fct(work->ht, work->i, work->start, work->len); |
7b17c13e | 1240 | work->ht->flavor->unregister_thread(); |
b7d619b0 MD |
1241 | return NULL; |
1242 | } | |
1243 | ||
1244 | static | |
1245 | void partition_resize_helper(struct cds_lfht *ht, unsigned long i, | |
1246 | unsigned long len, | |
1247 | void (*fct)(struct cds_lfht *ht, unsigned long i, | |
1248 | unsigned long start, unsigned long len)) | |
1249 | { | |
e54ec2f5 | 1250 | unsigned long partition_len, start = 0; |
b7d619b0 | 1251 | struct partition_resize_work *work; |
83e334d0 MJ |
1252 | int ret; |
1253 | unsigned long thread, nr_threads; | |
b7d619b0 | 1254 | |
01477510 | 1255 | urcu_posix_assert(nr_cpus_mask != -1); |
d7f3ba4c EW |
1256 | if (nr_cpus_mask < 0 || len < 2 * MIN_PARTITION_PER_THREAD) |
1257 | goto fallback; | |
1258 | ||
6083a889 MD |
1259 | /* |
1260 | * Note: nr_cpus_mask + 1 is always power of 2. | |
1261 | * We spawn just the number of threads we need to satisfy the minimum | |
1262 | * partition size, up to the number of CPUs in the system. | |
1263 | */ | |
91452a6a | 1264 | if (nr_cpus_mask > 0) { |
83e334d0 | 1265 | nr_threads = min_t(unsigned long, nr_cpus_mask + 1, |
91452a6a MD |
1266 | len >> MIN_PARTITION_PER_THREAD_ORDER); |
1267 | } else { | |
1268 | nr_threads = 1; | |
1269 | } | |
5bc6b66f | 1270 | partition_len = len >> cds_lfht_get_count_order_ulong(nr_threads); |
6083a889 | 1271 | work = calloc(nr_threads, sizeof(*work)); |
7c75d498 EW |
1272 | if (!work) { |
1273 | dbg_printf("error allocating for resize, single-threading\n"); | |
1274 | goto fallback; | |
1275 | } | |
6083a889 MD |
1276 | for (thread = 0; thread < nr_threads; thread++) { |
1277 | work[thread].ht = ht; | |
1278 | work[thread].i = i; | |
1279 | work[thread].len = partition_len; | |
1280 | work[thread].start = thread * partition_len; | |
1281 | work[thread].fct = fct; | |
1af6e26e | 1282 | ret = pthread_create(&(work[thread].thread_id), ht->resize_attr, |
6083a889 | 1283 | partition_resize_thread, &work[thread]); |
e54ec2f5 EW |
1284 | if (ret == EAGAIN) { |
1285 | /* | |
1286 | * Out of resources: wait and join the threads | |
1287 | * we've created, then handle leftovers. | |
1288 | */ | |
1289 | dbg_printf("error spawning for resize, single-threading\n"); | |
1290 | start = work[thread].start; | |
1291 | len -= start; | |
1292 | nr_threads = thread; | |
1293 | break; | |
1294 | } | |
01477510 | 1295 | urcu_posix_assert(!ret); |
b7d619b0 | 1296 | } |
6083a889 | 1297 | for (thread = 0; thread < nr_threads; thread++) { |
1af6e26e | 1298 | ret = pthread_join(work[thread].thread_id, NULL); |
01477510 | 1299 | urcu_posix_assert(!ret); |
b7d619b0 MD |
1300 | } |
1301 | free(work); | |
e54ec2f5 EW |
1302 | |
1303 | /* | |
1304 | * A pthread_create failure above will either lead in us having | |
1305 | * no threads to join or starting at a non-zero offset, | |
1306 | * fallback to single thread processing of leftovers. | |
1307 | */ | |
1308 | if (start == 0 && nr_threads > 0) | |
1309 | return; | |
7c75d498 | 1310 | fallback: |
e54ec2f5 | 1311 | fct(ht, i, start, len); |
b7d619b0 MD |
1312 | } |
1313 | ||
e8de508e MD |
1314 | /* |
1315 | * Holding RCU read lock to protect _cds_lfht_add against memory | |
d0ec0ed2 | 1316 | * reclaim that could be performed by other worker threads (ABA |
e8de508e | 1317 | * problem). |
9ee0fc9a | 1318 | * |
b7d619b0 | 1319 | * When we reach a certain length, we can split this population phase over |
9ee0fc9a MD |
1320 | * many worker threads, based on the number of CPUs available in the system. |
1321 | * This should therefore take care of not having the expand lagging behind too | |
1322 | * many concurrent insertion threads by using the scheduler's ability to | |
1ee8f000 | 1323 | * schedule bucket node population fairly with insertions. |
e8de508e | 1324 | */ |
4105056a | 1325 | static |
b7d619b0 MD |
1326 | void init_table_populate_partition(struct cds_lfht *ht, unsigned long i, |
1327 | unsigned long start, unsigned long len) | |
4105056a | 1328 | { |
9d72a73f | 1329 | unsigned long j, size = 1UL << (i - 1); |
4105056a | 1330 | |
01477510 | 1331 | urcu_posix_assert(i > MIN_TABLE_ORDER); |
7b17c13e | 1332 | ht->flavor->read_lock(); |
9d72a73f LJ |
1333 | for (j = size + start; j < size + start + len; j++) { |
1334 | struct cds_lfht_node *new_node = bucket_at(ht, j); | |
1335 | ||
01477510 | 1336 | urcu_posix_assert(j >= size && j < (size << 1)); |
9d72a73f LJ |
1337 | dbg_printf("init populate: order %lu index %lu hash %lu\n", |
1338 | i, j, j); | |
1339 | new_node->reverse_hash = bit_reverse_ulong(j); | |
91a75cc5 | 1340 | _cds_lfht_add(ht, j, NULL, NULL, size, new_node, NULL, 1); |
4105056a | 1341 | } |
7b17c13e | 1342 | ht->flavor->read_unlock(); |
b7d619b0 MD |
1343 | } |
1344 | ||
1345 | static | |
1346 | void init_table_populate(struct cds_lfht *ht, unsigned long i, | |
1347 | unsigned long len) | |
1348 | { | |
b7d619b0 | 1349 | partition_resize_helper(ht, i, len, init_table_populate_partition); |
4105056a MD |
1350 | } |
1351 | ||
abc490a1 | 1352 | static |
4105056a | 1353 | void init_table(struct cds_lfht *ht, |
93d46c39 | 1354 | unsigned long first_order, unsigned long last_order) |
24365af7 | 1355 | { |
93d46c39 | 1356 | unsigned long i; |
24365af7 | 1357 | |
93d46c39 LJ |
1358 | dbg_printf("init table: first_order %lu last_order %lu\n", |
1359 | first_order, last_order); | |
01477510 | 1360 | urcu_posix_assert(first_order > MIN_TABLE_ORDER); |
93d46c39 | 1361 | for (i = first_order; i <= last_order; i++) { |
4105056a | 1362 | unsigned long len; |
24365af7 | 1363 | |
4f6e90b7 | 1364 | len = 1UL << (i - 1); |
f0c29ed7 | 1365 | dbg_printf("init order %lu len: %lu\n", i, len); |
4d676753 MD |
1366 | |
1367 | /* Stop expand if the resize target changes under us */ | |
7b3893e4 | 1368 | if (CMM_LOAD_SHARED(ht->resize_target) < (1UL << i)) |
4d676753 MD |
1369 | break; |
1370 | ||
48f1b16d | 1371 | cds_lfht_alloc_bucket_table(ht, i); |
4105056a | 1372 | |
4105056a | 1373 | /* |
1ee8f000 LJ |
1374 | * Set all bucket nodes reverse hash values for a level and |
1375 | * link all bucket nodes into the table. | |
4105056a | 1376 | */ |
dc1da8f6 | 1377 | init_table_populate(ht, i, len); |
4105056a | 1378 | |
f9c80341 MD |
1379 | /* |
1380 | * Update table size. | |
1381 | */ | |
1382 | cmm_smp_wmb(); /* populate data before RCU size */ | |
7b3893e4 | 1383 | CMM_STORE_SHARED(ht->size, 1UL << i); |
f9c80341 | 1384 | |
4f6e90b7 | 1385 | dbg_printf("init new size: %lu\n", 1UL << i); |
4105056a MD |
1386 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
1387 | break; | |
1388 | } | |
1389 | } | |
1390 | ||
e8de508e MD |
1391 | /* |
1392 | * Holding RCU read lock to protect _cds_lfht_remove against memory | |
d0ec0ed2 | 1393 | * reclaim that could be performed by other worker threads (ABA |
e8de508e MD |
1394 | * problem). |
1395 | * For a single level, we logically remove and garbage collect each node. | |
1396 | * | |
1397 | * As a design choice, we perform logical removal and garbage collection on a | |
1398 | * node-per-node basis to simplify this algorithm. We also assume keeping good | |
1399 | * cache locality of the operation would overweight possible performance gain | |
1400 | * that could be achieved by batching garbage collection for multiple levels. | |
1401 | * However, this would have to be justified by benchmarks. | |
1402 | * | |
1403 | * Concurrent removal and add operations are helping us perform garbage | |
1404 | * collection of logically removed nodes. We guarantee that all logically | |
d0ec0ed2 MD |
1405 | * removed nodes have been garbage-collected (unlinked) before work |
1406 | * enqueue is invoked to free a hole level of bucket nodes (after a | |
1407 | * grace period). | |
e8de508e | 1408 | * |
1f67ba50 MD |
1409 | * Logical removal and garbage collection can therefore be done in batch |
1410 | * or on a node-per-node basis, as long as the guarantee above holds. | |
9ee0fc9a | 1411 | * |
b7d619b0 MD |
1412 | * When we reach a certain length, we can split this removal over many worker |
1413 | * threads, based on the number of CPUs available in the system. This should | |
1414 | * take care of not letting resize process lag behind too many concurrent | |
9ee0fc9a | 1415 | * updater threads actively inserting into the hash table. |
e8de508e | 1416 | */ |
4105056a | 1417 | static |
b7d619b0 MD |
1418 | void remove_table_partition(struct cds_lfht *ht, unsigned long i, |
1419 | unsigned long start, unsigned long len) | |
4105056a | 1420 | { |
9d72a73f | 1421 | unsigned long j, size = 1UL << (i - 1); |
4105056a | 1422 | |
01477510 | 1423 | urcu_posix_assert(i > MIN_TABLE_ORDER); |
7b17c13e | 1424 | ht->flavor->read_lock(); |
9d72a73f | 1425 | for (j = size + start; j < size + start + len; j++) { |
2e2ce1e9 LJ |
1426 | struct cds_lfht_node *fini_bucket = bucket_at(ht, j); |
1427 | struct cds_lfht_node *parent_bucket = bucket_at(ht, j - size); | |
9d72a73f | 1428 | |
01477510 | 1429 | urcu_posix_assert(j >= size && j < (size << 1)); |
9d72a73f LJ |
1430 | dbg_printf("remove entry: order %lu index %lu hash %lu\n", |
1431 | i, j, j); | |
2e2ce1e9 LJ |
1432 | /* Set the REMOVED_FLAG to freeze the ->next for gc */ |
1433 | uatomic_or(&fini_bucket->next, REMOVED_FLAG); | |
1434 | _cds_lfht_gc_bucket(parent_bucket, fini_bucket); | |
abc490a1 | 1435 | } |
7b17c13e | 1436 | ht->flavor->read_unlock(); |
b7d619b0 MD |
1437 | } |
1438 | ||
1439 | static | |
1440 | void remove_table(struct cds_lfht *ht, unsigned long i, unsigned long len) | |
1441 | { | |
b7d619b0 | 1442 | partition_resize_helper(ht, i, len, remove_table_partition); |
2ed95849 MD |
1443 | } |
1444 | ||
61adb337 MD |
1445 | /* |
1446 | * fini_table() is never called for first_order == 0, which is why | |
1447 | * free_by_rcu_order == 0 can be used as criterion to know if free must | |
1448 | * be called. | |
1449 | */ | |
1475579c | 1450 | static |
4105056a | 1451 | void fini_table(struct cds_lfht *ht, |
93d46c39 | 1452 | unsigned long first_order, unsigned long last_order) |
1475579c | 1453 | { |
83e334d0 | 1454 | unsigned long free_by_rcu_order = 0, i; |
1475579c | 1455 | |
93d46c39 LJ |
1456 | dbg_printf("fini table: first_order %lu last_order %lu\n", |
1457 | first_order, last_order); | |
01477510 | 1458 | urcu_posix_assert(first_order > MIN_TABLE_ORDER); |
93d46c39 | 1459 | for (i = last_order; i >= first_order; i--) { |
4105056a | 1460 | unsigned long len; |
1475579c | 1461 | |
4f6e90b7 | 1462 | len = 1UL << (i - 1); |
e15df1cc | 1463 | dbg_printf("fini order %ld len: %lu\n", i, len); |
4105056a | 1464 | |
4d676753 | 1465 | /* Stop shrink if the resize target changes under us */ |
7b3893e4 | 1466 | if (CMM_LOAD_SHARED(ht->resize_target) > (1UL << (i - 1))) |
4d676753 MD |
1467 | break; |
1468 | ||
1469 | cmm_smp_wmb(); /* populate data before RCU size */ | |
7b3893e4 | 1470 | CMM_STORE_SHARED(ht->size, 1UL << (i - 1)); |
4d676753 MD |
1471 | |
1472 | /* | |
1473 | * We need to wait for all add operations to reach Q.S. (and | |
1474 | * thus use the new table for lookups) before we can start | |
1ee8f000 | 1475 | * releasing the old bucket nodes. Otherwise their lookup will |
4d676753 MD |
1476 | * return a logically removed node as insert position. |
1477 | */ | |
7b17c13e | 1478 | ht->flavor->update_synchronize_rcu(); |
48f1b16d LJ |
1479 | if (free_by_rcu_order) |
1480 | cds_lfht_free_bucket_table(ht, free_by_rcu_order); | |
4d676753 | 1481 | |
21263e21 | 1482 | /* |
1ee8f000 LJ |
1483 | * Set "removed" flag in bucket nodes about to be removed. |
1484 | * Unlink all now-logically-removed bucket node pointers. | |
4105056a MD |
1485 | * Concurrent add/remove operation are helping us doing |
1486 | * the gc. | |
21263e21 | 1487 | */ |
4105056a MD |
1488 | remove_table(ht, i, len); |
1489 | ||
48f1b16d | 1490 | free_by_rcu_order = i; |
4105056a MD |
1491 | |
1492 | dbg_printf("fini new size: %lu\n", 1UL << i); | |
1475579c MD |
1493 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
1494 | break; | |
1495 | } | |
0d14ceb2 | 1496 | |
48f1b16d | 1497 | if (free_by_rcu_order) { |
7b17c13e | 1498 | ht->flavor->update_synchronize_rcu(); |
48f1b16d | 1499 | cds_lfht_free_bucket_table(ht, free_by_rcu_order); |
0d14ceb2 | 1500 | } |
1475579c MD |
1501 | } |
1502 | ||
83e334d0 MJ |
1503 | /* |
1504 | * Never called with size < 1. | |
1505 | */ | |
ff0d69de | 1506 | static |
1ee8f000 | 1507 | void cds_lfht_create_bucket(struct cds_lfht *ht, unsigned long size) |
ff0d69de | 1508 | { |
04db56f8 | 1509 | struct cds_lfht_node *prev, *node; |
9d72a73f | 1510 | unsigned long order, len, i; |
83e334d0 | 1511 | int bucket_order; |
ff0d69de | 1512 | |
48f1b16d | 1513 | cds_lfht_alloc_bucket_table(ht, 0); |
ff0d69de | 1514 | |
9d72a73f LJ |
1515 | dbg_printf("create bucket: order 0 index 0 hash 0\n"); |
1516 | node = bucket_at(ht, 0); | |
1517 | node->next = flag_bucket(get_end()); | |
1518 | node->reverse_hash = 0; | |
ff0d69de | 1519 | |
83e334d0 | 1520 | bucket_order = cds_lfht_get_count_order_ulong(size); |
01477510 | 1521 | urcu_posix_assert(bucket_order >= 0); |
83e334d0 MJ |
1522 | |
1523 | for (order = 1; order < (unsigned long) bucket_order + 1; order++) { | |
ff0d69de | 1524 | len = 1UL << (order - 1); |
48f1b16d | 1525 | cds_lfht_alloc_bucket_table(ht, order); |
ff0d69de | 1526 | |
9d72a73f LJ |
1527 | for (i = 0; i < len; i++) { |
1528 | /* | |
1529 | * Now, we are trying to init the node with the | |
1530 | * hash=(len+i) (which is also a bucket with the | |
1531 | * index=(len+i)) and insert it into the hash table, | |
1532 | * so this node has to be inserted after the bucket | |
1533 | * with the index=(len+i)&(len-1)=i. And because there | |
1534 | * is no other non-bucket node nor bucket node with | |
1535 | * larger index/hash inserted, so the bucket node | |
1536 | * being inserted should be inserted directly linked | |
1537 | * after the bucket node with index=i. | |
1538 | */ | |
1539 | prev = bucket_at(ht, i); | |
1540 | node = bucket_at(ht, len + i); | |
ff0d69de | 1541 | |
1ee8f000 | 1542 | dbg_printf("create bucket: order %lu index %lu hash %lu\n", |
9d72a73f LJ |
1543 | order, len + i, len + i); |
1544 | node->reverse_hash = bit_reverse_ulong(len + i); | |
1545 | ||
1546 | /* insert after prev */ | |
01477510 | 1547 | urcu_posix_assert(is_bucket(prev->next)); |
ff0d69de | 1548 | node->next = prev->next; |
1ee8f000 | 1549 | prev->next = flag_bucket(node); |
ff0d69de LJ |
1550 | } |
1551 | } | |
1552 | } | |
1553 | ||
99ab1528 MJ |
1554 | #if (CAA_BITS_PER_LONG > 32) |
1555 | /* | |
1556 | * For 64-bit architectures, with max number of buckets small enough not to | |
1557 | * use the entire 64-bit memory mapping space (and allowing a fair number of | |
1558 | * hash table instances), use the mmap allocator, which is faster. Otherwise, | |
1559 | * fallback to the order allocator. | |
1560 | */ | |
1561 | static | |
1562 | const struct cds_lfht_mm_type *get_mm_type(unsigned long max_nr_buckets) | |
1563 | { | |
1564 | if (max_nr_buckets && max_nr_buckets <= (1ULL << 32)) | |
1565 | return &cds_lfht_mm_mmap; | |
1566 | else | |
1567 | return &cds_lfht_mm_order; | |
1568 | } | |
1569 | #else | |
1570 | /* | |
1571 | * For 32-bit architectures, use the order allocator. | |
1572 | */ | |
1573 | static | |
70469b43 MJ |
1574 | const struct cds_lfht_mm_type *get_mm_type( |
1575 | unsigned long max_nr_buckets __attribute__((unused))) | |
99ab1528 MJ |
1576 | { |
1577 | return &cds_lfht_mm_order; | |
1578 | } | |
1579 | #endif | |
1580 | ||
0422d92c | 1581 | struct cds_lfht *_cds_lfht_new(unsigned long init_size, |
0722081a | 1582 | unsigned long min_nr_alloc_buckets, |
747d725c | 1583 | unsigned long max_nr_buckets, |
b8af5011 | 1584 | int flags, |
0b6aa001 | 1585 | const struct cds_lfht_mm_type *mm, |
7b17c13e | 1586 | const struct rcu_flavor_struct *flavor, |
b7d619b0 | 1587 | pthread_attr_t *attr) |
abc490a1 | 1588 | { |
14044b37 | 1589 | struct cds_lfht *ht; |
24365af7 | 1590 | unsigned long order; |
abc490a1 | 1591 | |
0722081a LJ |
1592 | /* min_nr_alloc_buckets must be power of two */ |
1593 | if (!min_nr_alloc_buckets || (min_nr_alloc_buckets & (min_nr_alloc_buckets - 1))) | |
5488222b | 1594 | return NULL; |
747d725c | 1595 | |
8129be4e | 1596 | /* init_size must be power of two */ |
5488222b | 1597 | if (!init_size || (init_size & (init_size - 1))) |
8129be4e | 1598 | return NULL; |
747d725c | 1599 | |
c1888f3a MD |
1600 | /* |
1601 | * Memory management plugin default. | |
1602 | */ | |
99ab1528 MJ |
1603 | if (!mm) |
1604 | mm = get_mm_type(max_nr_buckets); | |
c1888f3a | 1605 | |
0b6aa001 LJ |
1606 | /* max_nr_buckets == 0 for order based mm means infinite */ |
1607 | if (mm == &cds_lfht_mm_order && !max_nr_buckets) | |
747d725c LJ |
1608 | max_nr_buckets = 1UL << (MAX_TABLE_ORDER - 1); |
1609 | ||
1610 | /* max_nr_buckets must be power of two */ | |
1611 | if (!max_nr_buckets || (max_nr_buckets & (max_nr_buckets - 1))) | |
1612 | return NULL; | |
1613 | ||
d0ec0ed2 MD |
1614 | if (flags & CDS_LFHT_AUTO_RESIZE) |
1615 | cds_lfht_init_worker(flavor); | |
1616 | ||
0722081a | 1617 | min_nr_alloc_buckets = max(min_nr_alloc_buckets, MIN_TABLE_SIZE); |
d0d8f9aa | 1618 | init_size = max(init_size, MIN_TABLE_SIZE); |
747d725c LJ |
1619 | max_nr_buckets = max(max_nr_buckets, min_nr_alloc_buckets); |
1620 | init_size = min(init_size, max_nr_buckets); | |
0b6aa001 LJ |
1621 | |
1622 | ht = mm->alloc_cds_lfht(min_nr_alloc_buckets, max_nr_buckets); | |
01477510 FD |
1623 | urcu_posix_assert(ht); |
1624 | urcu_posix_assert(ht->mm == mm); | |
1625 | urcu_posix_assert(ht->bucket_at == mm->bucket_at); | |
0b6aa001 | 1626 | |
b5d6b20f | 1627 | ht->flags = flags; |
7b17c13e | 1628 | ht->flavor = flavor; |
b7d619b0 | 1629 | ht->resize_attr = attr; |
5afadd12 | 1630 | alloc_split_items_count(ht); |
abc490a1 MD |
1631 | /* this mutex should not nest in read-side C.S. */ |
1632 | pthread_mutex_init(&ht->resize_mutex, NULL); | |
5bc6b66f | 1633 | order = cds_lfht_get_count_order_ulong(init_size); |
7b3893e4 | 1634 | ht->resize_target = 1UL << order; |
1ee8f000 | 1635 | cds_lfht_create_bucket(ht, 1UL << order); |
7b3893e4 | 1636 | ht->size = 1UL << order; |
abc490a1 MD |
1637 | return ht; |
1638 | } | |
1639 | ||
6f554439 | 1640 | void cds_lfht_lookup(struct cds_lfht *ht, unsigned long hash, |
996ff57c | 1641 | cds_lfht_match_fct match, const void *key, |
6f554439 | 1642 | struct cds_lfht_iter *iter) |
2ed95849 | 1643 | { |
04db56f8 | 1644 | struct cds_lfht_node *node, *next, *bucket; |
0422d92c | 1645 | unsigned long reverse_hash, size; |
2ed95849 | 1646 | |
d7c76f85 MD |
1647 | cds_lfht_iter_debug_set_ht(ht, iter); |
1648 | ||
abc490a1 | 1649 | reverse_hash = bit_reverse_ulong(hash); |
464a1ec9 | 1650 | |
7b3893e4 | 1651 | size = rcu_dereference(ht->size); |
04db56f8 | 1652 | bucket = lookup_bucket(ht, size, hash); |
1ee8f000 | 1653 | /* We can always skip the bucket node initially */ |
04db56f8 | 1654 | node = rcu_dereference(bucket->next); |
bb7b2f26 | 1655 | node = clear_flag(node); |
2ed95849 | 1656 | for (;;) { |
8ed51e04 | 1657 | if (caa_unlikely(is_end(node))) { |
96ad1112 | 1658 | node = next = NULL; |
abc490a1 | 1659 | break; |
bb7b2f26 | 1660 | } |
04db56f8 | 1661 | if (caa_unlikely(node->reverse_hash > reverse_hash)) { |
96ad1112 | 1662 | node = next = NULL; |
abc490a1 | 1663 | break; |
2ed95849 | 1664 | } |
04db56f8 | 1665 | next = rcu_dereference(node->next); |
01477510 | 1666 | urcu_posix_assert(node == clear_flag(node)); |
8ed51e04 | 1667 | if (caa_likely(!is_removed(next)) |
1ee8f000 | 1668 | && !is_bucket(next) |
04db56f8 | 1669 | && node->reverse_hash == reverse_hash |
0422d92c | 1670 | && caa_likely(match(node, key))) { |
273399de | 1671 | break; |
2ed95849 | 1672 | } |
1b81fe1a | 1673 | node = clear_flag(next); |
2ed95849 | 1674 | } |
01477510 | 1675 | urcu_posix_assert(!node || !is_bucket(CMM_LOAD_SHARED(node->next))); |
adc0de68 MD |
1676 | iter->node = node; |
1677 | iter->next = next; | |
abc490a1 | 1678 | } |
e0ba718a | 1679 | |
70469b43 MJ |
1680 | void cds_lfht_next_duplicate(struct cds_lfht *ht __attribute__((unused)), |
1681 | cds_lfht_match_fct match, | |
996ff57c | 1682 | const void *key, struct cds_lfht_iter *iter) |
a481e5ff | 1683 | { |
adc0de68 | 1684 | struct cds_lfht_node *node, *next; |
a481e5ff | 1685 | unsigned long reverse_hash; |
a481e5ff | 1686 | |
d7c76f85 | 1687 | cds_lfht_iter_debug_assert(ht == iter->lfht); |
adc0de68 | 1688 | node = iter->node; |
04db56f8 | 1689 | reverse_hash = node->reverse_hash; |
adc0de68 | 1690 | next = iter->next; |
a481e5ff MD |
1691 | node = clear_flag(next); |
1692 | ||
1693 | for (;;) { | |
8ed51e04 | 1694 | if (caa_unlikely(is_end(node))) { |
96ad1112 | 1695 | node = next = NULL; |
a481e5ff | 1696 | break; |
bb7b2f26 | 1697 | } |
04db56f8 | 1698 | if (caa_unlikely(node->reverse_hash > reverse_hash)) { |
96ad1112 | 1699 | node = next = NULL; |
a481e5ff MD |
1700 | break; |
1701 | } | |
04db56f8 | 1702 | next = rcu_dereference(node->next); |
8ed51e04 | 1703 | if (caa_likely(!is_removed(next)) |
1ee8f000 | 1704 | && !is_bucket(next) |
04db56f8 | 1705 | && caa_likely(match(node, key))) { |
a481e5ff MD |
1706 | break; |
1707 | } | |
1708 | node = clear_flag(next); | |
1709 | } | |
01477510 | 1710 | urcu_posix_assert(!node || !is_bucket(CMM_LOAD_SHARED(node->next))); |
adc0de68 MD |
1711 | iter->node = node; |
1712 | iter->next = next; | |
a481e5ff MD |
1713 | } |
1714 | ||
70469b43 MJ |
1715 | void cds_lfht_next(struct cds_lfht *ht __attribute__((unused)), |
1716 | struct cds_lfht_iter *iter) | |
4e9b9fbf MD |
1717 | { |
1718 | struct cds_lfht_node *node, *next; | |
1719 | ||
d7c76f85 | 1720 | cds_lfht_iter_debug_assert(ht == iter->lfht); |
853395e1 | 1721 | node = clear_flag(iter->next); |
4e9b9fbf | 1722 | for (;;) { |
8ed51e04 | 1723 | if (caa_unlikely(is_end(node))) { |
4e9b9fbf MD |
1724 | node = next = NULL; |
1725 | break; | |
1726 | } | |
04db56f8 | 1727 | next = rcu_dereference(node->next); |
8ed51e04 | 1728 | if (caa_likely(!is_removed(next)) |
1ee8f000 | 1729 | && !is_bucket(next)) { |
4e9b9fbf MD |
1730 | break; |
1731 | } | |
1732 | node = clear_flag(next); | |
1733 | } | |
01477510 | 1734 | urcu_posix_assert(!node || !is_bucket(CMM_LOAD_SHARED(node->next))); |
4e9b9fbf MD |
1735 | iter->node = node; |
1736 | iter->next = next; | |
1737 | } | |
1738 | ||
1739 | void cds_lfht_first(struct cds_lfht *ht, struct cds_lfht_iter *iter) | |
1740 | { | |
d7c76f85 | 1741 | cds_lfht_iter_debug_set_ht(ht, iter); |
4e9b9fbf | 1742 | /* |
1ee8f000 | 1743 | * Get next after first bucket node. The first bucket node is the |
4e9b9fbf MD |
1744 | * first node of the linked list. |
1745 | */ | |
9d72a73f | 1746 | iter->next = bucket_at(ht, 0)->next; |
4e9b9fbf MD |
1747 | cds_lfht_next(ht, iter); |
1748 | } | |
1749 | ||
0422d92c MD |
1750 | void cds_lfht_add(struct cds_lfht *ht, unsigned long hash, |
1751 | struct cds_lfht_node *node) | |
abc490a1 | 1752 | { |
0422d92c | 1753 | unsigned long size; |
ab7d5fc6 | 1754 | |
709bacf9 | 1755 | node->reverse_hash = bit_reverse_ulong(hash); |
7b3893e4 | 1756 | size = rcu_dereference(ht->size); |
91a75cc5 | 1757 | _cds_lfht_add(ht, hash, NULL, NULL, size, node, NULL, 0); |
14360f1c | 1758 | ht_count_add(ht, size, hash); |
3eca1b8c MD |
1759 | } |
1760 | ||
14044b37 | 1761 | struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, |
6f554439 | 1762 | unsigned long hash, |
0422d92c | 1763 | cds_lfht_match_fct match, |
996ff57c | 1764 | const void *key, |
48ed1c18 | 1765 | struct cds_lfht_node *node) |
3eca1b8c | 1766 | { |
0422d92c | 1767 | unsigned long size; |
83beee94 | 1768 | struct cds_lfht_iter iter; |
3eca1b8c | 1769 | |
709bacf9 | 1770 | node->reverse_hash = bit_reverse_ulong(hash); |
7b3893e4 | 1771 | size = rcu_dereference(ht->size); |
91a75cc5 | 1772 | _cds_lfht_add(ht, hash, match, key, size, node, &iter, 0); |
83beee94 | 1773 | if (iter.node == node) |
14360f1c | 1774 | ht_count_add(ht, size, hash); |
83beee94 | 1775 | return iter.node; |
2ed95849 MD |
1776 | } |
1777 | ||
9357c415 | 1778 | struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht, |
6f554439 | 1779 | unsigned long hash, |
0422d92c | 1780 | cds_lfht_match_fct match, |
996ff57c | 1781 | const void *key, |
48ed1c18 MD |
1782 | struct cds_lfht_node *node) |
1783 | { | |
0422d92c | 1784 | unsigned long size; |
83beee94 | 1785 | struct cds_lfht_iter iter; |
48ed1c18 | 1786 | |
709bacf9 | 1787 | node->reverse_hash = bit_reverse_ulong(hash); |
7b3893e4 | 1788 | size = rcu_dereference(ht->size); |
83beee94 | 1789 | for (;;) { |
91a75cc5 | 1790 | _cds_lfht_add(ht, hash, match, key, size, node, &iter, 0); |
83beee94 | 1791 | if (iter.node == node) { |
14360f1c | 1792 | ht_count_add(ht, size, hash); |
83beee94 MD |
1793 | return NULL; |
1794 | } | |
1795 | ||
1796 | if (!_cds_lfht_replace(ht, size, iter.node, iter.next, node)) | |
1797 | return iter.node; | |
1798 | } | |
48ed1c18 MD |
1799 | } |
1800 | ||
2e79c445 MD |
1801 | int cds_lfht_replace(struct cds_lfht *ht, |
1802 | struct cds_lfht_iter *old_iter, | |
1803 | unsigned long hash, | |
1804 | cds_lfht_match_fct match, | |
1805 | const void *key, | |
9357c415 MD |
1806 | struct cds_lfht_node *new_node) |
1807 | { | |
1808 | unsigned long size; | |
1809 | ||
709bacf9 | 1810 | new_node->reverse_hash = bit_reverse_ulong(hash); |
2e79c445 MD |
1811 | if (!old_iter->node) |
1812 | return -ENOENT; | |
1813 | if (caa_unlikely(old_iter->node->reverse_hash != new_node->reverse_hash)) | |
1814 | return -EINVAL; | |
1815 | if (caa_unlikely(!match(old_iter->node, key))) | |
1816 | return -EINVAL; | |
7b3893e4 | 1817 | size = rcu_dereference(ht->size); |
9357c415 MD |
1818 | return _cds_lfht_replace(ht, size, old_iter->node, old_iter->next, |
1819 | new_node); | |
1820 | } | |
1821 | ||
bc8c3c74 | 1822 | int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_node *node) |
2ed95849 | 1823 | { |
95bc7fb9 | 1824 | unsigned long size; |
df44348d | 1825 | int ret; |
abc490a1 | 1826 | |
7b3893e4 | 1827 | size = rcu_dereference(ht->size); |
bc8c3c74 | 1828 | ret = _cds_lfht_del(ht, size, node); |
14360f1c | 1829 | if (!ret) { |
95bc7fb9 MD |
1830 | unsigned long hash; |
1831 | ||
bc8c3c74 | 1832 | hash = bit_reverse_ulong(node->reverse_hash); |
14360f1c LJ |
1833 | ht_count_del(ht, size, hash); |
1834 | } | |
df44348d | 1835 | return ret; |
2ed95849 | 1836 | } |
ab7d5fc6 | 1837 | |
afa5940d | 1838 | int cds_lfht_is_node_deleted(const struct cds_lfht_node *node) |
df55172a | 1839 | { |
a85eff52 | 1840 | return is_removed(CMM_LOAD_SHARED(node->next)); |
df55172a MD |
1841 | } |
1842 | ||
abc490a1 | 1843 | static |
1ee8f000 | 1844 | int cds_lfht_delete_bucket(struct cds_lfht *ht) |
674f7a69 | 1845 | { |
14044b37 | 1846 | struct cds_lfht_node *node; |
4105056a | 1847 | unsigned long order, i, size; |
674f7a69 | 1848 | |
abc490a1 | 1849 | /* Check that the table is empty */ |
9d72a73f | 1850 | node = bucket_at(ht, 0); |
abc490a1 | 1851 | do { |
04db56f8 | 1852 | node = clear_flag(node)->next; |
1ee8f000 | 1853 | if (!is_bucket(node)) |
abc490a1 | 1854 | return -EPERM; |
01477510 FD |
1855 | urcu_posix_assert(!is_removed(node)); |
1856 | urcu_posix_assert(!is_removal_owner(node)); | |
bb7b2f26 | 1857 | } while (!is_end(node)); |
4105056a MD |
1858 | /* |
1859 | * size accessed without rcu_dereference because hash table is | |
1860 | * being destroyed. | |
1861 | */ | |
7b3893e4 | 1862 | size = ht->size; |
1f67ba50 | 1863 | /* Internal sanity check: all nodes left should be buckets */ |
48f1b16d LJ |
1864 | for (i = 0; i < size; i++) { |
1865 | node = bucket_at(ht, i); | |
1866 | dbg_printf("delete bucket: index %lu expected hash %lu hash %lu\n", | |
1867 | i, i, bit_reverse_ulong(node->reverse_hash)); | |
01477510 | 1868 | urcu_posix_assert(is_bucket(node->next)); |
48f1b16d | 1869 | } |
24365af7 | 1870 | |
5bc6b66f | 1871 | for (order = cds_lfht_get_count_order_ulong(size); (long)order >= 0; order--) |
48f1b16d | 1872 | cds_lfht_free_bucket_table(ht, order); |
5488222b | 1873 | |
abc490a1 | 1874 | return 0; |
674f7a69 MD |
1875 | } |
1876 | ||
1877 | /* | |
1878 | * Should only be called when no more concurrent readers nor writers can | |
1879 | * possibly access the table. | |
1880 | */ | |
b7d619b0 | 1881 | int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr) |
674f7a69 | 1882 | { |
d0ec0ed2 MD |
1883 | int ret; |
1884 | ||
1885 | if (ht->flags & CDS_LFHT_AUTO_RESIZE) { | |
1886 | /* Cancel ongoing resize operations. */ | |
1887 | _CMM_STORE_SHARED(ht->in_progress_destroy, 1); | |
1888 | /* Wait for in-flight resize operations to complete */ | |
1889 | urcu_workqueue_flush_queued_work(cds_lfht_workqueue); | |
10e68472 | 1890 | } |
1ee8f000 | 1891 | ret = cds_lfht_delete_bucket(ht); |
abc490a1 MD |
1892 | if (ret) |
1893 | return ret; | |
5afadd12 | 1894 | free_split_items_count(ht); |
b7d619b0 MD |
1895 | if (attr) |
1896 | *attr = ht->resize_attr; | |
59629f09 MD |
1897 | ret = pthread_mutex_destroy(&ht->resize_mutex); |
1898 | if (ret) | |
1899 | ret = -EBUSY; | |
d0ec0ed2 MD |
1900 | if (ht->flags & CDS_LFHT_AUTO_RESIZE) |
1901 | cds_lfht_fini_worker(ht->flavor); | |
98808fb1 | 1902 | poison_free(ht); |
5e28c532 | 1903 | return ret; |
674f7a69 MD |
1904 | } |
1905 | ||
14044b37 | 1906 | void cds_lfht_count_nodes(struct cds_lfht *ht, |
d933dd0e | 1907 | long *approx_before, |
273399de | 1908 | unsigned long *count, |
d933dd0e | 1909 | long *approx_after) |
273399de | 1910 | { |
14044b37 | 1911 | struct cds_lfht_node *node, *next; |
caf3653d | 1912 | unsigned long nr_bucket = 0, nr_removed = 0; |
273399de | 1913 | |
7ed7682f | 1914 | *approx_before = 0; |
5afadd12 | 1915 | if (ht->split_count) { |
973e5e1b MD |
1916 | int i; |
1917 | ||
4c42f1b8 LJ |
1918 | for (i = 0; i < split_count_mask + 1; i++) { |
1919 | *approx_before += uatomic_read(&ht->split_count[i].add); | |
1920 | *approx_before -= uatomic_read(&ht->split_count[i].del); | |
973e5e1b MD |
1921 | } |
1922 | } | |
1923 | ||
273399de | 1924 | *count = 0; |
273399de | 1925 | |
1ee8f000 | 1926 | /* Count non-bucket nodes in the table */ |
9d72a73f | 1927 | node = bucket_at(ht, 0); |
273399de | 1928 | do { |
04db56f8 | 1929 | next = rcu_dereference(node->next); |
b198f0fd | 1930 | if (is_removed(next)) { |
1ee8f000 | 1931 | if (!is_bucket(next)) |
caf3653d | 1932 | (nr_removed)++; |
973e5e1b | 1933 | else |
1ee8f000 LJ |
1934 | (nr_bucket)++; |
1935 | } else if (!is_bucket(next)) | |
273399de | 1936 | (*count)++; |
24365af7 | 1937 | else |
1ee8f000 | 1938 | (nr_bucket)++; |
273399de | 1939 | node = clear_flag(next); |
bb7b2f26 | 1940 | } while (!is_end(node)); |
caf3653d | 1941 | dbg_printf("number of logically removed nodes: %lu\n", nr_removed); |
1ee8f000 | 1942 | dbg_printf("number of bucket nodes: %lu\n", nr_bucket); |
7ed7682f | 1943 | *approx_after = 0; |
5afadd12 | 1944 | if (ht->split_count) { |
973e5e1b MD |
1945 | int i; |
1946 | ||
4c42f1b8 LJ |
1947 | for (i = 0; i < split_count_mask + 1; i++) { |
1948 | *approx_after += uatomic_read(&ht->split_count[i].add); | |
1949 | *approx_after -= uatomic_read(&ht->split_count[i].del); | |
973e5e1b MD |
1950 | } |
1951 | } | |
273399de MD |
1952 | } |
1953 | ||
1475579c | 1954 | /* called with resize mutex held */ |
abc490a1 | 1955 | static |
4105056a | 1956 | void _do_cds_lfht_grow(struct cds_lfht *ht, |
1475579c | 1957 | unsigned long old_size, unsigned long new_size) |
abc490a1 | 1958 | { |
1475579c | 1959 | unsigned long old_order, new_order; |
1475579c | 1960 | |
5bc6b66f MD |
1961 | old_order = cds_lfht_get_count_order_ulong(old_size); |
1962 | new_order = cds_lfht_get_count_order_ulong(new_size); | |
1a401918 LJ |
1963 | dbg_printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", |
1964 | old_size, old_order, new_size, new_order); | |
01477510 | 1965 | urcu_posix_assert(new_size > old_size); |
93d46c39 | 1966 | init_table(ht, old_order + 1, new_order); |
abc490a1 MD |
1967 | } |
1968 | ||
1969 | /* called with resize mutex held */ | |
1970 | static | |
4105056a | 1971 | void _do_cds_lfht_shrink(struct cds_lfht *ht, |
1475579c | 1972 | unsigned long old_size, unsigned long new_size) |
464a1ec9 | 1973 | { |
1475579c | 1974 | unsigned long old_order, new_order; |
464a1ec9 | 1975 | |
d0d8f9aa | 1976 | new_size = max(new_size, MIN_TABLE_SIZE); |
5bc6b66f MD |
1977 | old_order = cds_lfht_get_count_order_ulong(old_size); |
1978 | new_order = cds_lfht_get_count_order_ulong(new_size); | |
1a401918 LJ |
1979 | dbg_printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", |
1980 | old_size, old_order, new_size, new_order); | |
01477510 | 1981 | urcu_posix_assert(new_size < old_size); |
1475579c | 1982 | |
1ee8f000 | 1983 | /* Remove and unlink all bucket nodes to remove. */ |
93d46c39 | 1984 | fini_table(ht, new_order + 1, old_order); |
464a1ec9 MD |
1985 | } |
1986 | ||
1475579c MD |
1987 | |
1988 | /* called with resize mutex held */ | |
1989 | static | |
1990 | void _do_cds_lfht_resize(struct cds_lfht *ht) | |
1991 | { | |
1992 | unsigned long new_size, old_size; | |
4105056a MD |
1993 | |
1994 | /* | |
1995 | * Resize table, re-do if the target size has changed under us. | |
1996 | */ | |
1997 | do { | |
d2be3620 MD |
1998 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
1999 | break; | |
7b3893e4 LJ |
2000 | ht->resize_initiated = 1; |
2001 | old_size = ht->size; | |
2002 | new_size = CMM_LOAD_SHARED(ht->resize_target); | |
4105056a MD |
2003 | if (old_size < new_size) |
2004 | _do_cds_lfht_grow(ht, old_size, new_size); | |
2005 | else if (old_size > new_size) | |
2006 | _do_cds_lfht_shrink(ht, old_size, new_size); | |
7b3893e4 | 2007 | ht->resize_initiated = 0; |
4105056a MD |
2008 | /* write resize_initiated before read resize_target */ |
2009 | cmm_smp_mb(); | |
7b3893e4 | 2010 | } while (ht->size != CMM_LOAD_SHARED(ht->resize_target)); |
1475579c MD |
2011 | } |
2012 | ||
abc490a1 | 2013 | static |
ab65b890 | 2014 | unsigned long resize_target_grow(struct cds_lfht *ht, unsigned long new_size) |
464a1ec9 | 2015 | { |
7b3893e4 | 2016 | return _uatomic_xchg_monotonic_increase(&ht->resize_target, new_size); |
464a1ec9 MD |
2017 | } |
2018 | ||
1475579c | 2019 | static |
4105056a | 2020 | void resize_target_update_count(struct cds_lfht *ht, |
b8af5011 | 2021 | unsigned long count) |
1475579c | 2022 | { |
d0d8f9aa | 2023 | count = max(count, MIN_TABLE_SIZE); |
747d725c | 2024 | count = min(count, ht->max_nr_buckets); |
7b3893e4 | 2025 | uatomic_set(&ht->resize_target, count); |
1475579c MD |
2026 | } |
2027 | ||
2028 | void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size) | |
464a1ec9 | 2029 | { |
10e68472 MD |
2030 | resize_target_update_count(ht, new_size); |
2031 | CMM_STORE_SHARED(ht->resize_initiated, 1); | |
5ffcaeef | 2032 | mutex_lock(&ht->resize_mutex); |
1475579c | 2033 | _do_cds_lfht_resize(ht); |
5ffcaeef | 2034 | mutex_unlock(&ht->resize_mutex); |
abc490a1 | 2035 | } |
464a1ec9 | 2036 | |
abc490a1 | 2037 | static |
d0ec0ed2 | 2038 | void do_resize_cb(struct urcu_work *work) |
abc490a1 | 2039 | { |
d0ec0ed2 MD |
2040 | struct resize_work *resize_work = |
2041 | caa_container_of(work, struct resize_work, work); | |
2042 | struct cds_lfht *ht = resize_work->ht; | |
abc490a1 | 2043 | |
d0ec0ed2 | 2044 | ht->flavor->register_thread(); |
5ffcaeef | 2045 | mutex_lock(&ht->resize_mutex); |
14044b37 | 2046 | _do_cds_lfht_resize(ht); |
5ffcaeef | 2047 | mutex_unlock(&ht->resize_mutex); |
d0ec0ed2 | 2048 | ht->flavor->unregister_thread(); |
98808fb1 | 2049 | poison_free(work); |
464a1ec9 MD |
2050 | } |
2051 | ||
abc490a1 | 2052 | static |
f1f119ee | 2053 | void __cds_lfht_resize_lazy_launch(struct cds_lfht *ht) |
ab7d5fc6 | 2054 | { |
d0ec0ed2 | 2055 | struct resize_work *work; |
abc490a1 | 2056 | |
4105056a MD |
2057 | /* Store resize_target before read resize_initiated */ |
2058 | cmm_smp_mb(); | |
7b3893e4 | 2059 | if (!CMM_LOAD_SHARED(ht->resize_initiated)) { |
ed35e6d8 | 2060 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) { |
59290e9d | 2061 | return; |
ed35e6d8 | 2062 | } |
f9830efd | 2063 | work = malloc(sizeof(*work)); |
741f378e MD |
2064 | if (work == NULL) { |
2065 | dbg_printf("error allocating resize work, bailing out\n"); | |
741f378e MD |
2066 | return; |
2067 | } | |
f9830efd | 2068 | work->ht = ht; |
d0ec0ed2 MD |
2069 | urcu_workqueue_queue_work(cds_lfht_workqueue, |
2070 | &work->work, do_resize_cb); | |
7b3893e4 | 2071 | CMM_STORE_SHARED(ht->resize_initiated, 1); |
f9830efd | 2072 | } |
ab7d5fc6 | 2073 | } |
3171717f | 2074 | |
f1f119ee LJ |
2075 | static |
2076 | void cds_lfht_resize_lazy_grow(struct cds_lfht *ht, unsigned long size, int growth) | |
2077 | { | |
2078 | unsigned long target_size = size << growth; | |
2079 | ||
747d725c | 2080 | target_size = min(target_size, ht->max_nr_buckets); |
f1f119ee LJ |
2081 | if (resize_target_grow(ht, target_size) >= target_size) |
2082 | return; | |
2083 | ||
2084 | __cds_lfht_resize_lazy_launch(ht); | |
2085 | } | |
2086 | ||
89bb121d LJ |
2087 | /* |
2088 | * We favor grow operations over shrink. A shrink operation never occurs | |
2089 | * if a grow operation is queued for lazy execution. A grow operation | |
2090 | * cancels any pending shrink lazy execution. | |
2091 | */ | |
3171717f | 2092 | static |
4105056a | 2093 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, |
3171717f MD |
2094 | unsigned long count) |
2095 | { | |
b8af5011 MD |
2096 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) |
2097 | return; | |
d0d8f9aa | 2098 | count = max(count, MIN_TABLE_SIZE); |
747d725c | 2099 | count = min(count, ht->max_nr_buckets); |
89bb121d LJ |
2100 | if (count == size) |
2101 | return; /* Already the right size, no resize needed */ | |
2102 | if (count > size) { /* lazy grow */ | |
2103 | if (resize_target_grow(ht, count) >= count) | |
2104 | return; | |
2105 | } else { /* lazy shrink */ | |
2106 | for (;;) { | |
2107 | unsigned long s; | |
2108 | ||
7b3893e4 | 2109 | s = uatomic_cmpxchg(&ht->resize_target, size, count); |
89bb121d LJ |
2110 | if (s == size) |
2111 | break; /* no resize needed */ | |
2112 | if (s > size) | |
2113 | return; /* growing is/(was just) in progress */ | |
2114 | if (s <= count) | |
2115 | return; /* some other thread do shrink */ | |
2116 | size = s; | |
2117 | } | |
2118 | } | |
f1f119ee | 2119 | __cds_lfht_resize_lazy_launch(ht); |
3171717f | 2120 | } |
d0ec0ed2 | 2121 | |
70469b43 | 2122 | static void cds_lfht_before_fork(void *priv __attribute__((unused))) |
d0ec0ed2 MD |
2123 | { |
2124 | if (cds_lfht_workqueue_atfork_nesting++) | |
2125 | return; | |
2126 | mutex_lock(&cds_lfht_fork_mutex); | |
2127 | if (!cds_lfht_workqueue) | |
2128 | return; | |
2129 | urcu_workqueue_pause_worker(cds_lfht_workqueue); | |
2130 | } | |
2131 | ||
70469b43 | 2132 | static void cds_lfht_after_fork_parent(void *priv __attribute__((unused))) |
d0ec0ed2 MD |
2133 | { |
2134 | if (--cds_lfht_workqueue_atfork_nesting) | |
2135 | return; | |
2136 | if (!cds_lfht_workqueue) | |
2137 | goto end; | |
2138 | urcu_workqueue_resume_worker(cds_lfht_workqueue); | |
2139 | end: | |
2140 | mutex_unlock(&cds_lfht_fork_mutex); | |
2141 | } | |
2142 | ||
70469b43 | 2143 | static void cds_lfht_after_fork_child(void *priv __attribute__((unused))) |
d0ec0ed2 MD |
2144 | { |
2145 | if (--cds_lfht_workqueue_atfork_nesting) | |
2146 | return; | |
2147 | if (!cds_lfht_workqueue) | |
2148 | goto end; | |
2149 | urcu_workqueue_create_worker(cds_lfht_workqueue); | |
2150 | end: | |
2151 | mutex_unlock(&cds_lfht_fork_mutex); | |
2152 | } | |
2153 | ||
2154 | static struct urcu_atfork cds_lfht_atfork = { | |
2155 | .before_fork = cds_lfht_before_fork, | |
2156 | .after_fork_parent = cds_lfht_after_fork_parent, | |
2157 | .after_fork_child = cds_lfht_after_fork_child, | |
2158 | }; | |
2159 | ||
1a990de3 | 2160 | /* |
2161 | * Block all signals for the workqueue worker thread to ensure we don't | |
2162 | * disturb the application. The SIGRCU signal needs to be unblocked for | |
2163 | * the urcu-signal flavor. | |
2164 | */ | |
70469b43 MJ |
2165 | static void cds_lfht_worker_init( |
2166 | struct urcu_workqueue *workqueue __attribute__((unused)), | |
2167 | void *priv __attribute__((unused))) | |
d0ec0ed2 MD |
2168 | { |
2169 | int ret; | |
2170 | sigset_t mask; | |
2171 | ||
d0ec0ed2 MD |
2172 | ret = sigfillset(&mask); |
2173 | if (ret) | |
2174 | urcu_die(errno); | |
1a990de3 | 2175 | ret = sigdelset(&mask, SIGRCU); |
2176 | if (ret) | |
9fd30396 | 2177 | urcu_die(errno); |
1a990de3 | 2178 | ret = pthread_sigmask(SIG_SETMASK, &mask, NULL); |
d0ec0ed2 MD |
2179 | if (ret) |
2180 | urcu_die(ret); | |
2181 | } | |
2182 | ||
2183 | static void cds_lfht_init_worker(const struct rcu_flavor_struct *flavor) | |
2184 | { | |
2185 | flavor->register_rculfhash_atfork(&cds_lfht_atfork); | |
2186 | ||
2187 | mutex_lock(&cds_lfht_fork_mutex); | |
2188 | if (cds_lfht_workqueue_user_count++) | |
2189 | goto end; | |
2190 | cds_lfht_workqueue = urcu_workqueue_create(0, -1, NULL, | |
2191 | NULL, cds_lfht_worker_init, NULL, NULL, NULL, NULL, NULL); | |
2192 | end: | |
2193 | mutex_unlock(&cds_lfht_fork_mutex); | |
2194 | } | |
2195 | ||
2196 | static void cds_lfht_fini_worker(const struct rcu_flavor_struct *flavor) | |
2197 | { | |
2198 | mutex_lock(&cds_lfht_fork_mutex); | |
2199 | if (--cds_lfht_workqueue_user_count) | |
2200 | goto end; | |
2201 | urcu_workqueue_destroy(cds_lfht_workqueue); | |
2202 | cds_lfht_workqueue = NULL; | |
2203 | end: | |
2204 | mutex_unlock(&cds_lfht_fork_mutex); | |
2205 | ||
2206 | flavor->unregister_rculfhash_atfork(&cds_lfht_atfork); | |
2207 | } |