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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 MD |
66 | * - Resize operation initiated by long chain detection is executed by a |
67 | * call_rcu thread, which keeps lock-freedom of add and remove. | |
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 | 258 | #define _LGPL_SOURCE |
125f41db | 259 | #define _GNU_SOURCE |
2ed95849 | 260 | #include <stdlib.h> |
e0ba718a MD |
261 | #include <errno.h> |
262 | #include <assert.h> | |
263 | #include <stdio.h> | |
abc490a1 | 264 | #include <stdint.h> |
f000907d | 265 | #include <string.h> |
125f41db | 266 | #include <sched.h> |
e0ba718a | 267 | |
15cfbec7 | 268 | #include "config.h" |
a47dd11c | 269 | #include "compat-getcpu.h" |
2ed95849 | 270 | #include <urcu.h> |
abc490a1 | 271 | #include <urcu-call-rcu.h> |
7b17c13e | 272 | #include <urcu-flavor.h> |
a42cc659 MD |
273 | #include <urcu/arch.h> |
274 | #include <urcu/uatomic.h> | |
a42cc659 | 275 | #include <urcu/compiler.h> |
abc490a1 | 276 | #include <urcu/rculfhash.h> |
0b6aa001 | 277 | #include <rculfhash-internal.h> |
5e28c532 | 278 | #include <stdio.h> |
464a1ec9 | 279 | #include <pthread.h> |
44395fb7 | 280 | |
f8994aee | 281 | /* |
4c42f1b8 | 282 | * Split-counters lazily update the global counter each 1024 |
f8994aee MD |
283 | * addition/removal. It automatically keeps track of resize required. |
284 | * We use the bucket length as indicator for need to expand for small | |
ffa11a18 | 285 | * tables and machines lacking per-cpu data support. |
f8994aee MD |
286 | */ |
287 | #define COUNT_COMMIT_ORDER 10 | |
4ddbb355 | 288 | #define DEFAULT_SPLIT_COUNT_MASK 0xFUL |
6ea6bc67 MD |
289 | #define CHAIN_LEN_TARGET 1 |
290 | #define CHAIN_LEN_RESIZE_THRESHOLD 3 | |
2ed95849 | 291 | |
cd95516d | 292 | /* |
76a73da8 | 293 | * Define the minimum table size. |
cd95516d | 294 | */ |
d0d8f9aa LJ |
295 | #define MIN_TABLE_ORDER 0 |
296 | #define MIN_TABLE_SIZE (1UL << MIN_TABLE_ORDER) | |
cd95516d | 297 | |
b7d619b0 | 298 | /* |
1ee8f000 | 299 | * Minimum number of bucket nodes to touch per thread to parallelize grow/shrink. |
b7d619b0 | 300 | */ |
6083a889 MD |
301 | #define MIN_PARTITION_PER_THREAD_ORDER 12 |
302 | #define MIN_PARTITION_PER_THREAD (1UL << MIN_PARTITION_PER_THREAD_ORDER) | |
b7d619b0 | 303 | |
d95bd160 MD |
304 | /* |
305 | * The removed flag needs to be updated atomically with the pointer. | |
48ed1c18 | 306 | * It indicates that no node must attach to the node scheduled for |
b198f0fd | 307 | * removal, and that node garbage collection must be performed. |
1ee8f000 | 308 | * The bucket flag does not require to be updated atomically with the |
d95bd160 | 309 | * pointer, but it is added as a pointer low bit flag to save space. |
1f67ba50 MD |
310 | * The "removal owner" flag is used to detect which of the "del" |
311 | * operation that has set the "removed flag" gets to return the removed | |
312 | * node to its caller. Note that the replace operation does not need to | |
313 | * iteract with the "removal owner" flag, because it validates that | |
314 | * the "removed" flag is not set before performing its cmpxchg. | |
d95bd160 | 315 | */ |
d37166c6 | 316 | #define REMOVED_FLAG (1UL << 0) |
1ee8f000 | 317 | #define BUCKET_FLAG (1UL << 1) |
db00ccc3 MD |
318 | #define REMOVAL_OWNER_FLAG (1UL << 2) |
319 | #define FLAGS_MASK ((1UL << 3) - 1) | |
d37166c6 | 320 | |
bb7b2f26 | 321 | /* Value of the end pointer. Should not interact with flags. */ |
f9c80341 | 322 | #define END_VALUE NULL |
bb7b2f26 | 323 | |
7f52427b MD |
324 | /* |
325 | * ht_items_count: Split-counters counting the number of node addition | |
326 | * and removal in the table. Only used if the CDS_LFHT_ACCOUNTING flag | |
327 | * is set at hash table creation. | |
328 | * | |
329 | * These are free-running counters, never reset to zero. They count the | |
330 | * number of add/remove, and trigger every (1 << COUNT_COMMIT_ORDER) | |
331 | * operations to update the global counter. We choose a power-of-2 value | |
332 | * for the trigger to deal with 32 or 64-bit overflow of the counter. | |
333 | */ | |
df44348d | 334 | struct ht_items_count { |
860d07e8 | 335 | unsigned long add, del; |
df44348d MD |
336 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
337 | ||
7f52427b MD |
338 | /* |
339 | * rcu_resize_work: Contains arguments passed to RCU worker thread | |
340 | * responsible for performing lazy resize. | |
341 | */ | |
abc490a1 MD |
342 | struct rcu_resize_work { |
343 | struct rcu_head head; | |
14044b37 | 344 | struct cds_lfht *ht; |
abc490a1 | 345 | }; |
2ed95849 | 346 | |
7f52427b MD |
347 | /* |
348 | * partition_resize_work: Contains arguments passed to worker threads | |
349 | * executing the hash table resize on partitions of the hash table | |
350 | * assigned to each processor's worker thread. | |
351 | */ | |
b7d619b0 | 352 | struct partition_resize_work { |
1af6e26e | 353 | pthread_t thread_id; |
b7d619b0 MD |
354 | struct cds_lfht *ht; |
355 | unsigned long i, start, len; | |
356 | void (*fct)(struct cds_lfht *ht, unsigned long i, | |
357 | unsigned long start, unsigned long len); | |
358 | }; | |
359 | ||
abc490a1 MD |
360 | /* |
361 | * Algorithm to reverse bits in a word by lookup table, extended to | |
362 | * 64-bit words. | |
f9830efd | 363 | * Source: |
abc490a1 | 364 | * http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable |
f9830efd | 365 | * Originally from Public Domain. |
abc490a1 MD |
366 | */ |
367 | ||
67ecffc0 | 368 | static const uint8_t BitReverseTable256[256] = |
2ed95849 | 369 | { |
abc490a1 MD |
370 | #define R2(n) (n), (n) + 2*64, (n) + 1*64, (n) + 3*64 |
371 | #define R4(n) R2(n), R2((n) + 2*16), R2((n) + 1*16), R2((n) + 3*16) | |
372 | #define R6(n) R4(n), R4((n) + 2*4 ), R4((n) + 1*4 ), R4((n) + 3*4 ) | |
373 | R6(0), R6(2), R6(1), R6(3) | |
374 | }; | |
375 | #undef R2 | |
376 | #undef R4 | |
377 | #undef R6 | |
2ed95849 | 378 | |
abc490a1 MD |
379 | static |
380 | uint8_t bit_reverse_u8(uint8_t v) | |
381 | { | |
382 | return BitReverseTable256[v]; | |
383 | } | |
ab7d5fc6 | 384 | |
95bc7fb9 MD |
385 | #if (CAA_BITS_PER_LONG == 32) |
386 | static | |
abc490a1 MD |
387 | uint32_t bit_reverse_u32(uint32_t v) |
388 | { | |
67ecffc0 MD |
389 | return ((uint32_t) bit_reverse_u8(v) << 24) | |
390 | ((uint32_t) bit_reverse_u8(v >> 8) << 16) | | |
391 | ((uint32_t) bit_reverse_u8(v >> 16) << 8) | | |
abc490a1 | 392 | ((uint32_t) bit_reverse_u8(v >> 24)); |
2ed95849 | 393 | } |
95bc7fb9 MD |
394 | #else |
395 | static | |
abc490a1 | 396 | uint64_t bit_reverse_u64(uint64_t v) |
2ed95849 | 397 | { |
67ecffc0 MD |
398 | return ((uint64_t) bit_reverse_u8(v) << 56) | |
399 | ((uint64_t) bit_reverse_u8(v >> 8) << 48) | | |
abc490a1 MD |
400 | ((uint64_t) bit_reverse_u8(v >> 16) << 40) | |
401 | ((uint64_t) bit_reverse_u8(v >> 24) << 32) | | |
67ecffc0 MD |
402 | ((uint64_t) bit_reverse_u8(v >> 32) << 24) | |
403 | ((uint64_t) bit_reverse_u8(v >> 40) << 16) | | |
abc490a1 MD |
404 | ((uint64_t) bit_reverse_u8(v >> 48) << 8) | |
405 | ((uint64_t) bit_reverse_u8(v >> 56)); | |
406 | } | |
95bc7fb9 | 407 | #endif |
abc490a1 MD |
408 | |
409 | static | |
410 | unsigned long bit_reverse_ulong(unsigned long v) | |
411 | { | |
412 | #if (CAA_BITS_PER_LONG == 32) | |
413 | return bit_reverse_u32(v); | |
414 | #else | |
415 | return bit_reverse_u64(v); | |
416 | #endif | |
417 | } | |
418 | ||
f9830efd | 419 | /* |
24365af7 MD |
420 | * fls: returns the position of the most significant bit. |
421 | * Returns 0 if no bit is set, else returns the position of the most | |
422 | * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit). | |
f9830efd | 423 | */ |
24365af7 MD |
424 | #if defined(__i386) || defined(__x86_64) |
425 | static inline | |
426 | unsigned int fls_u32(uint32_t x) | |
f9830efd | 427 | { |
24365af7 MD |
428 | int r; |
429 | ||
e1789ce2 | 430 | __asm__ ("bsrl %1,%0\n\t" |
24365af7 MD |
431 | "jnz 1f\n\t" |
432 | "movl $-1,%0\n\t" | |
433 | "1:\n\t" | |
434 | : "=r" (r) : "rm" (x)); | |
435 | return r + 1; | |
436 | } | |
437 | #define HAS_FLS_U32 | |
438 | #endif | |
439 | ||
440 | #if defined(__x86_64) | |
441 | static inline | |
442 | unsigned int fls_u64(uint64_t x) | |
443 | { | |
444 | long r; | |
445 | ||
e1789ce2 | 446 | __asm__ ("bsrq %1,%0\n\t" |
24365af7 MD |
447 | "jnz 1f\n\t" |
448 | "movq $-1,%0\n\t" | |
449 | "1:\n\t" | |
450 | : "=r" (r) : "rm" (x)); | |
451 | return r + 1; | |
452 | } | |
453 | #define HAS_FLS_U64 | |
454 | #endif | |
455 | ||
456 | #ifndef HAS_FLS_U64 | |
457 | static __attribute__((unused)) | |
458 | unsigned int fls_u64(uint64_t x) | |
459 | { | |
460 | unsigned int r = 64; | |
461 | ||
462 | if (!x) | |
463 | return 0; | |
464 | ||
465 | if (!(x & 0xFFFFFFFF00000000ULL)) { | |
466 | x <<= 32; | |
467 | r -= 32; | |
468 | } | |
469 | if (!(x & 0xFFFF000000000000ULL)) { | |
470 | x <<= 16; | |
471 | r -= 16; | |
472 | } | |
473 | if (!(x & 0xFF00000000000000ULL)) { | |
474 | x <<= 8; | |
475 | r -= 8; | |
476 | } | |
477 | if (!(x & 0xF000000000000000ULL)) { | |
478 | x <<= 4; | |
479 | r -= 4; | |
480 | } | |
481 | if (!(x & 0xC000000000000000ULL)) { | |
482 | x <<= 2; | |
483 | r -= 2; | |
484 | } | |
485 | if (!(x & 0x8000000000000000ULL)) { | |
486 | x <<= 1; | |
487 | r -= 1; | |
488 | } | |
489 | return r; | |
490 | } | |
491 | #endif | |
492 | ||
493 | #ifndef HAS_FLS_U32 | |
494 | static __attribute__((unused)) | |
495 | unsigned int fls_u32(uint32_t x) | |
496 | { | |
497 | unsigned int r = 32; | |
f9830efd | 498 | |
24365af7 MD |
499 | if (!x) |
500 | return 0; | |
501 | if (!(x & 0xFFFF0000U)) { | |
502 | x <<= 16; | |
503 | r -= 16; | |
504 | } | |
505 | if (!(x & 0xFF000000U)) { | |
506 | x <<= 8; | |
507 | r -= 8; | |
508 | } | |
509 | if (!(x & 0xF0000000U)) { | |
510 | x <<= 4; | |
511 | r -= 4; | |
512 | } | |
513 | if (!(x & 0xC0000000U)) { | |
514 | x <<= 2; | |
515 | r -= 2; | |
516 | } | |
517 | if (!(x & 0x80000000U)) { | |
518 | x <<= 1; | |
519 | r -= 1; | |
520 | } | |
521 | return r; | |
522 | } | |
523 | #endif | |
524 | ||
5bc6b66f | 525 | unsigned int cds_lfht_fls_ulong(unsigned long x) |
f9830efd | 526 | { |
6887cc5e | 527 | #if (CAA_BITS_PER_LONG == 32) |
24365af7 MD |
528 | return fls_u32(x); |
529 | #else | |
530 | return fls_u64(x); | |
531 | #endif | |
532 | } | |
f9830efd | 533 | |
920f8ef6 LJ |
534 | /* |
535 | * Return the minimum order for which x <= (1UL << order). | |
536 | * Return -1 if x is 0. | |
537 | */ | |
5bc6b66f | 538 | int cds_lfht_get_count_order_u32(uint32_t x) |
24365af7 | 539 | { |
920f8ef6 LJ |
540 | if (!x) |
541 | return -1; | |
24365af7 | 542 | |
920f8ef6 | 543 | return fls_u32(x - 1); |
24365af7 MD |
544 | } |
545 | ||
920f8ef6 LJ |
546 | /* |
547 | * Return the minimum order for which x <= (1UL << order). | |
548 | * Return -1 if x is 0. | |
549 | */ | |
5bc6b66f | 550 | int cds_lfht_get_count_order_ulong(unsigned long x) |
24365af7 | 551 | { |
920f8ef6 LJ |
552 | if (!x) |
553 | return -1; | |
24365af7 | 554 | |
5bc6b66f | 555 | return cds_lfht_fls_ulong(x - 1); |
f9830efd MD |
556 | } |
557 | ||
558 | static | |
ab65b890 | 559 | void cds_lfht_resize_lazy_grow(struct cds_lfht *ht, unsigned long size, int growth); |
f9830efd | 560 | |
f8994aee | 561 | static |
4105056a | 562 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, |
f8994aee MD |
563 | unsigned long count); |
564 | ||
df44348d | 565 | static long nr_cpus_mask = -1; |
4c42f1b8 | 566 | static long split_count_mask = -1; |
e53ab1eb | 567 | static int split_count_order = -1; |
4c42f1b8 | 568 | |
4ddbb355 | 569 | #if defined(HAVE_SYSCONF) |
4c42f1b8 LJ |
570 | static void ht_init_nr_cpus_mask(void) |
571 | { | |
572 | long maxcpus; | |
573 | ||
574 | maxcpus = sysconf(_SC_NPROCESSORS_CONF); | |
575 | if (maxcpus <= 0) { | |
576 | nr_cpus_mask = -2; | |
577 | return; | |
578 | } | |
579 | /* | |
580 | * round up number of CPUs to next power of two, so we | |
581 | * can use & for modulo. | |
582 | */ | |
5bc6b66f | 583 | maxcpus = 1UL << cds_lfht_get_count_order_ulong(maxcpus); |
4c42f1b8 LJ |
584 | nr_cpus_mask = maxcpus - 1; |
585 | } | |
4ddbb355 LJ |
586 | #else /* #if defined(HAVE_SYSCONF) */ |
587 | static void ht_init_nr_cpus_mask(void) | |
588 | { | |
589 | nr_cpus_mask = -2; | |
590 | } | |
591 | #endif /* #else #if defined(HAVE_SYSCONF) */ | |
df44348d MD |
592 | |
593 | static | |
5afadd12 | 594 | void alloc_split_items_count(struct cds_lfht *ht) |
df44348d | 595 | { |
4c42f1b8 LJ |
596 | if (nr_cpus_mask == -1) { |
597 | ht_init_nr_cpus_mask(); | |
4ddbb355 LJ |
598 | if (nr_cpus_mask < 0) |
599 | split_count_mask = DEFAULT_SPLIT_COUNT_MASK; | |
600 | else | |
601 | split_count_mask = nr_cpus_mask; | |
e53ab1eb MD |
602 | split_count_order = |
603 | cds_lfht_get_count_order_ulong(split_count_mask + 1); | |
df44348d | 604 | } |
4c42f1b8 | 605 | |
4ddbb355 | 606 | assert(split_count_mask >= 0); |
5afadd12 LJ |
607 | |
608 | if (ht->flags & CDS_LFHT_ACCOUNTING) { | |
95bc7fb9 MD |
609 | ht->split_count = calloc(split_count_mask + 1, |
610 | sizeof(struct ht_items_count)); | |
5afadd12 LJ |
611 | assert(ht->split_count); |
612 | } else { | |
613 | ht->split_count = NULL; | |
614 | } | |
df44348d MD |
615 | } |
616 | ||
617 | static | |
5afadd12 | 618 | void free_split_items_count(struct cds_lfht *ht) |
df44348d | 619 | { |
5afadd12 | 620 | poison_free(ht->split_count); |
df44348d MD |
621 | } |
622 | ||
623 | static | |
14360f1c | 624 | int ht_get_split_count_index(unsigned long hash) |
df44348d MD |
625 | { |
626 | int cpu; | |
627 | ||
4c42f1b8 | 628 | assert(split_count_mask >= 0); |
a47dd11c | 629 | cpu = urcu_sched_getcpu(); |
8ed51e04 | 630 | if (caa_unlikely(cpu < 0)) |
14360f1c | 631 | return hash & split_count_mask; |
df44348d | 632 | else |
4c42f1b8 | 633 | return cpu & split_count_mask; |
df44348d MD |
634 | } |
635 | ||
636 | static | |
14360f1c | 637 | void ht_count_add(struct cds_lfht *ht, unsigned long size, unsigned long hash) |
df44348d | 638 | { |
4c42f1b8 LJ |
639 | unsigned long split_count; |
640 | int index; | |
314558bf | 641 | long count; |
df44348d | 642 | |
8ed51e04 | 643 | if (caa_unlikely(!ht->split_count)) |
3171717f | 644 | return; |
14360f1c | 645 | index = ht_get_split_count_index(hash); |
4c42f1b8 | 646 | split_count = uatomic_add_return(&ht->split_count[index].add, 1); |
314558bf MD |
647 | if (caa_likely(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1))) |
648 | return; | |
649 | /* Only if number of add multiple of 1UL << COUNT_COMMIT_ORDER */ | |
650 | ||
651 | dbg_printf("add split count %lu\n", split_count); | |
652 | count = uatomic_add_return(&ht->count, | |
653 | 1UL << COUNT_COMMIT_ORDER); | |
4c299dcb | 654 | if (caa_likely(count & (count - 1))) |
314558bf MD |
655 | return; |
656 | /* Only if global count is power of 2 */ | |
657 | ||
658 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) < size) | |
659 | return; | |
660 | dbg_printf("add set global %ld\n", count); | |
661 | cds_lfht_resize_lazy_count(ht, size, | |
662 | count >> (CHAIN_LEN_TARGET - 1)); | |
df44348d MD |
663 | } |
664 | ||
665 | static | |
14360f1c | 666 | void ht_count_del(struct cds_lfht *ht, unsigned long size, unsigned long hash) |
df44348d | 667 | { |
4c42f1b8 LJ |
668 | unsigned long split_count; |
669 | int index; | |
314558bf | 670 | long count; |
df44348d | 671 | |
8ed51e04 | 672 | if (caa_unlikely(!ht->split_count)) |
3171717f | 673 | return; |
14360f1c | 674 | index = ht_get_split_count_index(hash); |
4c42f1b8 | 675 | split_count = uatomic_add_return(&ht->split_count[index].del, 1); |
314558bf MD |
676 | if (caa_likely(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1))) |
677 | return; | |
678 | /* Only if number of deletes multiple of 1UL << COUNT_COMMIT_ORDER */ | |
679 | ||
680 | dbg_printf("del split count %lu\n", split_count); | |
681 | count = uatomic_add_return(&ht->count, | |
682 | -(1UL << COUNT_COMMIT_ORDER)); | |
4c299dcb | 683 | if (caa_likely(count & (count - 1))) |
314558bf MD |
684 | return; |
685 | /* Only if global count is power of 2 */ | |
686 | ||
687 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) >= size) | |
688 | return; | |
689 | dbg_printf("del set global %ld\n", count); | |
690 | /* | |
691 | * Don't shrink table if the number of nodes is below a | |
692 | * certain threshold. | |
693 | */ | |
694 | if (count < (1UL << COUNT_COMMIT_ORDER) * (split_count_mask + 1)) | |
695 | return; | |
696 | cds_lfht_resize_lazy_count(ht, size, | |
697 | count >> (CHAIN_LEN_TARGET - 1)); | |
df44348d MD |
698 | } |
699 | ||
f9830efd | 700 | static |
4105056a | 701 | void check_resize(struct cds_lfht *ht, unsigned long size, uint32_t chain_len) |
f9830efd | 702 | { |
f8994aee MD |
703 | unsigned long count; |
704 | ||
b8af5011 MD |
705 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) |
706 | return; | |
f8994aee MD |
707 | count = uatomic_read(&ht->count); |
708 | /* | |
709 | * Use bucket-local length for small table expand and for | |
710 | * environments lacking per-cpu data support. | |
711 | */ | |
e53ab1eb | 712 | if (count >= (1UL << (COUNT_COMMIT_ORDER + split_count_order))) |
f8994aee | 713 | return; |
24365af7 | 714 | if (chain_len > 100) |
f0c29ed7 | 715 | dbg_printf("WARNING: large chain length: %u.\n", |
24365af7 | 716 | chain_len); |
e53ab1eb MD |
717 | if (chain_len >= CHAIN_LEN_RESIZE_THRESHOLD) { |
718 | int growth; | |
719 | ||
720 | /* | |
721 | * Ideal growth calculated based on chain length. | |
722 | */ | |
723 | growth = cds_lfht_get_count_order_u32(chain_len | |
724 | - (CHAIN_LEN_TARGET - 1)); | |
725 | if ((ht->flags & CDS_LFHT_ACCOUNTING) | |
726 | && (size << growth) | |
727 | >= (1UL << (COUNT_COMMIT_ORDER | |
728 | + split_count_order))) { | |
729 | /* | |
730 | * If ideal growth expands the hash table size | |
731 | * beyond the "small hash table" sizes, use the | |
732 | * maximum small hash table size to attempt | |
733 | * expanding the hash table. This only applies | |
734 | * when node accounting is available, otherwise | |
735 | * the chain length is used to expand the hash | |
736 | * table in every case. | |
737 | */ | |
738 | growth = COUNT_COMMIT_ORDER + split_count_order | |
739 | - cds_lfht_get_count_order_ulong(size); | |
740 | if (growth <= 0) | |
741 | return; | |
742 | } | |
743 | cds_lfht_resize_lazy_grow(ht, size, growth); | |
744 | } | |
f9830efd MD |
745 | } |
746 | ||
abc490a1 | 747 | static |
14044b37 | 748 | struct cds_lfht_node *clear_flag(struct cds_lfht_node *node) |
abc490a1 | 749 | { |
14044b37 | 750 | return (struct cds_lfht_node *) (((unsigned long) node) & ~FLAGS_MASK); |
abc490a1 MD |
751 | } |
752 | ||
753 | static | |
14044b37 | 754 | int is_removed(struct cds_lfht_node *node) |
abc490a1 | 755 | { |
d37166c6 | 756 | return ((unsigned long) node) & REMOVED_FLAG; |
abc490a1 MD |
757 | } |
758 | ||
f5596c94 | 759 | static |
1ee8f000 | 760 | int is_bucket(struct cds_lfht_node *node) |
f5596c94 | 761 | { |
1ee8f000 | 762 | return ((unsigned long) node) & BUCKET_FLAG; |
f5596c94 MD |
763 | } |
764 | ||
765 | static | |
1ee8f000 | 766 | struct cds_lfht_node *flag_bucket(struct cds_lfht_node *node) |
f5596c94 | 767 | { |
1ee8f000 | 768 | return (struct cds_lfht_node *) (((unsigned long) node) | BUCKET_FLAG); |
f5596c94 | 769 | } |
bb7b2f26 | 770 | |
db00ccc3 MD |
771 | static |
772 | int is_removal_owner(struct cds_lfht_node *node) | |
773 | { | |
774 | return ((unsigned long) node) & REMOVAL_OWNER_FLAG; | |
775 | } | |
776 | ||
777 | static | |
778 | struct cds_lfht_node *flag_removal_owner(struct cds_lfht_node *node) | |
779 | { | |
780 | return (struct cds_lfht_node *) (((unsigned long) node) | REMOVAL_OWNER_FLAG); | |
781 | } | |
782 | ||
71bb3aca MD |
783 | static |
784 | struct cds_lfht_node *flag_removed_or_removal_owner(struct cds_lfht_node *node) | |
785 | { | |
786 | return (struct cds_lfht_node *) (((unsigned long) node) | REMOVED_FLAG | REMOVAL_OWNER_FLAG); | |
787 | } | |
788 | ||
bb7b2f26 MD |
789 | static |
790 | struct cds_lfht_node *get_end(void) | |
791 | { | |
792 | return (struct cds_lfht_node *) END_VALUE; | |
793 | } | |
794 | ||
795 | static | |
796 | int is_end(struct cds_lfht_node *node) | |
797 | { | |
798 | return clear_flag(node) == (struct cds_lfht_node *) END_VALUE; | |
799 | } | |
800 | ||
abc490a1 | 801 | static |
ab65b890 LJ |
802 | unsigned long _uatomic_xchg_monotonic_increase(unsigned long *ptr, |
803 | unsigned long v) | |
abc490a1 MD |
804 | { |
805 | unsigned long old1, old2; | |
806 | ||
807 | old1 = uatomic_read(ptr); | |
808 | do { | |
809 | old2 = old1; | |
810 | if (old2 >= v) | |
f9830efd | 811 | return old2; |
abc490a1 | 812 | } while ((old1 = uatomic_cmpxchg(ptr, old2, v)) != old2); |
ab65b890 | 813 | return old2; |
abc490a1 MD |
814 | } |
815 | ||
48f1b16d LJ |
816 | static |
817 | void cds_lfht_alloc_bucket_table(struct cds_lfht *ht, unsigned long order) | |
818 | { | |
0b6aa001 | 819 | return ht->mm->alloc_bucket_table(ht, order); |
48f1b16d LJ |
820 | } |
821 | ||
822 | /* | |
823 | * cds_lfht_free_bucket_table() should be called with decreasing order. | |
824 | * When cds_lfht_free_bucket_table(0) is called, it means the whole | |
825 | * lfht is destroyed. | |
826 | */ | |
827 | static | |
828 | void cds_lfht_free_bucket_table(struct cds_lfht *ht, unsigned long order) | |
829 | { | |
0b6aa001 | 830 | return ht->mm->free_bucket_table(ht, order); |
48f1b16d LJ |
831 | } |
832 | ||
9d72a73f LJ |
833 | static inline |
834 | struct cds_lfht_node *bucket_at(struct cds_lfht *ht, unsigned long index) | |
f4a9cc0b | 835 | { |
0b6aa001 | 836 | return ht->bucket_at(ht, index); |
f4a9cc0b LJ |
837 | } |
838 | ||
9d72a73f LJ |
839 | static inline |
840 | struct cds_lfht_node *lookup_bucket(struct cds_lfht *ht, unsigned long size, | |
841 | unsigned long hash) | |
842 | { | |
843 | assert(size > 0); | |
844 | return bucket_at(ht, hash & (size - 1)); | |
845 | } | |
846 | ||
273399de MD |
847 | /* |
848 | * Remove all logically deleted nodes from a bucket up to a certain node key. | |
849 | */ | |
850 | static | |
1ee8f000 | 851 | void _cds_lfht_gc_bucket(struct cds_lfht_node *bucket, struct cds_lfht_node *node) |
273399de | 852 | { |
14044b37 | 853 | struct cds_lfht_node *iter_prev, *iter, *next, *new_next; |
273399de | 854 | |
1ee8f000 LJ |
855 | assert(!is_bucket(bucket)); |
856 | assert(!is_removed(bucket)); | |
2f943cd7 | 857 | assert(!is_removal_owner(bucket)); |
1ee8f000 | 858 | assert(!is_bucket(node)); |
c90201ac | 859 | assert(!is_removed(node)); |
2f943cd7 | 860 | assert(!is_removal_owner(node)); |
273399de | 861 | for (;;) { |
1ee8f000 LJ |
862 | iter_prev = bucket; |
863 | /* We can always skip the bucket node initially */ | |
04db56f8 | 864 | iter = rcu_dereference(iter_prev->next); |
b4cb483f | 865 | assert(!is_removed(iter)); |
2f943cd7 | 866 | assert(!is_removal_owner(iter)); |
04db56f8 | 867 | assert(iter_prev->reverse_hash <= node->reverse_hash); |
bd4db153 | 868 | /* |
1ee8f000 | 869 | * We should never be called with bucket (start of chain) |
bd4db153 MD |
870 | * and logically removed node (end of path compression |
871 | * marker) being the actual same node. This would be a | |
872 | * bug in the algorithm implementation. | |
873 | */ | |
1ee8f000 | 874 | assert(bucket != node); |
273399de | 875 | for (;;) { |
8ed51e04 | 876 | if (caa_unlikely(is_end(iter))) |
f9c80341 | 877 | return; |
04db56f8 | 878 | if (caa_likely(clear_flag(iter)->reverse_hash > node->reverse_hash)) |
f9c80341 | 879 | return; |
04db56f8 | 880 | next = rcu_dereference(clear_flag(iter)->next); |
8ed51e04 | 881 | if (caa_likely(is_removed(next))) |
273399de | 882 | break; |
b453eae1 | 883 | iter_prev = clear_flag(iter); |
273399de MD |
884 | iter = next; |
885 | } | |
b198f0fd | 886 | assert(!is_removed(iter)); |
2f943cd7 | 887 | assert(!is_removal_owner(iter)); |
1ee8f000 LJ |
888 | if (is_bucket(iter)) |
889 | new_next = flag_bucket(clear_flag(next)); | |
f5596c94 MD |
890 | else |
891 | new_next = clear_flag(next); | |
04db56f8 | 892 | (void) uatomic_cmpxchg(&iter_prev->next, iter, new_next); |
273399de MD |
893 | } |
894 | } | |
895 | ||
9357c415 MD |
896 | static |
897 | int _cds_lfht_replace(struct cds_lfht *ht, unsigned long size, | |
898 | struct cds_lfht_node *old_node, | |
3fb86f26 | 899 | struct cds_lfht_node *old_next, |
9357c415 MD |
900 | struct cds_lfht_node *new_node) |
901 | { | |
04db56f8 | 902 | struct cds_lfht_node *bucket, *ret_next; |
9357c415 MD |
903 | |
904 | if (!old_node) /* Return -ENOENT if asked to replace NULL node */ | |
7801dadd | 905 | return -ENOENT; |
9357c415 MD |
906 | |
907 | assert(!is_removed(old_node)); | |
2f943cd7 | 908 | assert(!is_removal_owner(old_node)); |
1ee8f000 | 909 | assert(!is_bucket(old_node)); |
9357c415 | 910 | assert(!is_removed(new_node)); |
2f943cd7 | 911 | assert(!is_removal_owner(new_node)); |
1ee8f000 | 912 | assert(!is_bucket(new_node)); |
9357c415 | 913 | assert(new_node != old_node); |
3fb86f26 | 914 | for (;;) { |
9357c415 | 915 | /* Insert after node to be replaced */ |
9357c415 MD |
916 | if (is_removed(old_next)) { |
917 | /* | |
918 | * Too late, the old node has been removed under us | |
919 | * between lookup and replace. Fail. | |
920 | */ | |
7801dadd | 921 | return -ENOENT; |
9357c415 | 922 | } |
feda2722 LJ |
923 | assert(old_next == clear_flag(old_next)); |
924 | assert(new_node != old_next); | |
71bb3aca MD |
925 | /* |
926 | * REMOVAL_OWNER flag is _NEVER_ set before the REMOVED | |
927 | * flag. It is either set atomically at the same time | |
928 | * (replace) or after (del). | |
929 | */ | |
930 | assert(!is_removal_owner(old_next)); | |
feda2722 | 931 | new_node->next = old_next; |
9357c415 MD |
932 | /* |
933 | * Here is the whole trick for lock-free replace: we add | |
934 | * the replacement node _after_ the node we want to | |
935 | * replace by atomically setting its next pointer at the | |
936 | * same time we set its removal flag. Given that | |
937 | * the lookups/get next use an iterator aware of the | |
938 | * next pointer, they will either skip the old node due | |
939 | * to the removal flag and see the new node, or use | |
940 | * the old node, but will not see the new one. | |
db00ccc3 MD |
941 | * This is a replacement of a node with another node |
942 | * that has the same value: we are therefore not | |
71bb3aca MD |
943 | * removing a value from the hash table. We set both the |
944 | * REMOVED and REMOVAL_OWNER flags atomically so we own | |
945 | * the node after successful cmpxchg. | |
9357c415 | 946 | */ |
04db56f8 | 947 | ret_next = uatomic_cmpxchg(&old_node->next, |
71bb3aca | 948 | old_next, flag_removed_or_removal_owner(new_node)); |
3fb86f26 | 949 | if (ret_next == old_next) |
7801dadd | 950 | break; /* We performed the replacement. */ |
3fb86f26 LJ |
951 | old_next = ret_next; |
952 | } | |
9357c415 | 953 | |
9357c415 MD |
954 | /* |
955 | * Ensure that the old node is not visible to readers anymore: | |
956 | * lookup for the node, and remove it (along with any other | |
957 | * logically removed node) if found. | |
958 | */ | |
04db56f8 LJ |
959 | bucket = lookup_bucket(ht, size, bit_reverse_ulong(old_node->reverse_hash)); |
960 | _cds_lfht_gc_bucket(bucket, new_node); | |
7801dadd | 961 | |
a85eff52 | 962 | assert(is_removed(CMM_LOAD_SHARED(old_node->next))); |
7801dadd | 963 | return 0; |
9357c415 MD |
964 | } |
965 | ||
83beee94 MD |
966 | /* |
967 | * A non-NULL unique_ret pointer uses the "add unique" (or uniquify) add | |
968 | * mode. A NULL unique_ret allows creation of duplicate keys. | |
969 | */ | |
abc490a1 | 970 | static |
83beee94 | 971 | void _cds_lfht_add(struct cds_lfht *ht, |
91a75cc5 | 972 | unsigned long hash, |
0422d92c | 973 | cds_lfht_match_fct match, |
996ff57c | 974 | const void *key, |
83beee94 MD |
975 | unsigned long size, |
976 | struct cds_lfht_node *node, | |
977 | struct cds_lfht_iter *unique_ret, | |
1ee8f000 | 978 | int bucket_flag) |
abc490a1 | 979 | { |
14044b37 | 980 | struct cds_lfht_node *iter_prev, *iter, *next, *new_node, *new_next, |
960c9e4f | 981 | *return_node; |
04db56f8 | 982 | struct cds_lfht_node *bucket; |
abc490a1 | 983 | |
1ee8f000 | 984 | assert(!is_bucket(node)); |
c90201ac | 985 | assert(!is_removed(node)); |
2f943cd7 | 986 | assert(!is_removal_owner(node)); |
91a75cc5 | 987 | bucket = lookup_bucket(ht, size, hash); |
abc490a1 | 988 | for (;;) { |
adc0de68 | 989 | uint32_t chain_len = 0; |
abc490a1 | 990 | |
11519af6 MD |
991 | /* |
992 | * iter_prev points to the non-removed node prior to the | |
993 | * insert location. | |
11519af6 | 994 | */ |
04db56f8 | 995 | iter_prev = bucket; |
1ee8f000 | 996 | /* We can always skip the bucket node initially */ |
04db56f8 LJ |
997 | iter = rcu_dereference(iter_prev->next); |
998 | assert(iter_prev->reverse_hash <= node->reverse_hash); | |
abc490a1 | 999 | for (;;) { |
8ed51e04 | 1000 | if (caa_unlikely(is_end(iter))) |
273399de | 1001 | goto insert; |
04db56f8 | 1002 | if (caa_likely(clear_flag(iter)->reverse_hash > node->reverse_hash)) |
273399de | 1003 | goto insert; |
238cc06e | 1004 | |
1ee8f000 LJ |
1005 | /* bucket node is the first node of the identical-hash-value chain */ |
1006 | if (bucket_flag && clear_flag(iter)->reverse_hash == node->reverse_hash) | |
194fdbd1 | 1007 | goto insert; |
238cc06e | 1008 | |
04db56f8 | 1009 | next = rcu_dereference(clear_flag(iter)->next); |
8ed51e04 | 1010 | if (caa_unlikely(is_removed(next))) |
9dba85be | 1011 | goto gc_node; |
238cc06e LJ |
1012 | |
1013 | /* uniquely add */ | |
83beee94 | 1014 | if (unique_ret |
1ee8f000 | 1015 | && !is_bucket(next) |
04db56f8 | 1016 | && clear_flag(iter)->reverse_hash == node->reverse_hash) { |
238cc06e LJ |
1017 | struct cds_lfht_iter d_iter = { .node = node, .next = iter, }; |
1018 | ||
1019 | /* | |
1020 | * uniquely adding inserts the node as the first | |
1021 | * node of the identical-hash-value node chain. | |
1022 | * | |
1023 | * This semantic ensures no duplicated keys | |
1024 | * should ever be observable in the table | |
1f67ba50 MD |
1025 | * (including traversing the table node by |
1026 | * node by forward iterations) | |
238cc06e | 1027 | */ |
04db56f8 | 1028 | cds_lfht_next_duplicate(ht, match, key, &d_iter); |
238cc06e LJ |
1029 | if (!d_iter.node) |
1030 | goto insert; | |
1031 | ||
1032 | *unique_ret = d_iter; | |
83beee94 | 1033 | return; |
48ed1c18 | 1034 | } |
238cc06e | 1035 | |
11519af6 | 1036 | /* Only account for identical reverse hash once */ |
04db56f8 | 1037 | if (iter_prev->reverse_hash != clear_flag(iter)->reverse_hash |
1ee8f000 | 1038 | && !is_bucket(next)) |
4105056a | 1039 | check_resize(ht, size, ++chain_len); |
11519af6 | 1040 | iter_prev = clear_flag(iter); |
273399de | 1041 | iter = next; |
abc490a1 | 1042 | } |
48ed1c18 | 1043 | |
273399de | 1044 | insert: |
7ec59d3b | 1045 | assert(node != clear_flag(iter)); |
11519af6 | 1046 | assert(!is_removed(iter_prev)); |
2f943cd7 | 1047 | assert(!is_removal_owner(iter_prev)); |
c90201ac | 1048 | assert(!is_removed(iter)); |
2f943cd7 | 1049 | assert(!is_removal_owner(iter)); |
f000907d | 1050 | assert(iter_prev != node); |
1ee8f000 | 1051 | if (!bucket_flag) |
04db56f8 | 1052 | node->next = clear_flag(iter); |
f9c80341 | 1053 | else |
1ee8f000 LJ |
1054 | node->next = flag_bucket(clear_flag(iter)); |
1055 | if (is_bucket(iter)) | |
1056 | new_node = flag_bucket(node); | |
f5596c94 MD |
1057 | else |
1058 | new_node = node; | |
04db56f8 | 1059 | if (uatomic_cmpxchg(&iter_prev->next, iter, |
48ed1c18 | 1060 | new_node) != iter) { |
273399de | 1061 | continue; /* retry */ |
48ed1c18 | 1062 | } else { |
83beee94 | 1063 | return_node = node; |
960c9e4f | 1064 | goto end; |
48ed1c18 MD |
1065 | } |
1066 | ||
9dba85be MD |
1067 | gc_node: |
1068 | assert(!is_removed(iter)); | |
2f943cd7 | 1069 | assert(!is_removal_owner(iter)); |
1ee8f000 LJ |
1070 | if (is_bucket(iter)) |
1071 | new_next = flag_bucket(clear_flag(next)); | |
f5596c94 MD |
1072 | else |
1073 | new_next = clear_flag(next); | |
04db56f8 | 1074 | (void) uatomic_cmpxchg(&iter_prev->next, iter, new_next); |
273399de | 1075 | /* retry */ |
464a1ec9 | 1076 | } |
9357c415 | 1077 | end: |
83beee94 MD |
1078 | if (unique_ret) { |
1079 | unique_ret->node = return_node; | |
1080 | /* unique_ret->next left unset, never used. */ | |
1081 | } | |
abc490a1 | 1082 | } |
464a1ec9 | 1083 | |
abc490a1 | 1084 | static |
860d07e8 | 1085 | int _cds_lfht_del(struct cds_lfht *ht, unsigned long size, |
b65ec430 | 1086 | struct cds_lfht_node *node) |
abc490a1 | 1087 | { |
db00ccc3 | 1088 | struct cds_lfht_node *bucket, *next; |
5e28c532 | 1089 | |
9357c415 | 1090 | if (!node) /* Return -ENOENT if asked to delete NULL node */ |
743f9143 | 1091 | return -ENOENT; |
9357c415 | 1092 | |
7ec59d3b | 1093 | /* logically delete the node */ |
1ee8f000 | 1094 | assert(!is_bucket(node)); |
c90201ac | 1095 | assert(!is_removed(node)); |
db00ccc3 | 1096 | assert(!is_removal_owner(node)); |
48ed1c18 | 1097 | |
db00ccc3 MD |
1098 | /* |
1099 | * We are first checking if the node had previously been | |
1100 | * logically removed (this check is not atomic with setting the | |
1101 | * logical removal flag). Return -ENOENT if the node had | |
1102 | * previously been removed. | |
1103 | */ | |
a85eff52 | 1104 | next = CMM_LOAD_SHARED(node->next); /* next is not dereferenced */ |
db00ccc3 MD |
1105 | if (caa_unlikely(is_removed(next))) |
1106 | return -ENOENT; | |
b65ec430 | 1107 | assert(!is_bucket(next)); |
196f4fab MD |
1108 | /* |
1109 | * The del operation semantic guarantees a full memory barrier | |
1110 | * before the uatomic_or atomic commit of the deletion flag. | |
1111 | */ | |
1112 | cmm_smp_mb__before_uatomic_or(); | |
db00ccc3 MD |
1113 | /* |
1114 | * We set the REMOVED_FLAG unconditionally. Note that there may | |
1115 | * be more than one concurrent thread setting this flag. | |
1116 | * Knowing which wins the race will be known after the garbage | |
1117 | * collection phase, stay tuned! | |
1118 | */ | |
1119 | uatomic_or(&node->next, REMOVED_FLAG); | |
7ec59d3b | 1120 | /* We performed the (logical) deletion. */ |
7ec59d3b MD |
1121 | |
1122 | /* | |
1123 | * Ensure that the node is not visible to readers anymore: lookup for | |
273399de MD |
1124 | * the node, and remove it (along with any other logically removed node) |
1125 | * if found. | |
11519af6 | 1126 | */ |
04db56f8 LJ |
1127 | bucket = lookup_bucket(ht, size, bit_reverse_ulong(node->reverse_hash)); |
1128 | _cds_lfht_gc_bucket(bucket, node); | |
743f9143 | 1129 | |
a85eff52 | 1130 | assert(is_removed(CMM_LOAD_SHARED(node->next))); |
db00ccc3 MD |
1131 | /* |
1132 | * Last phase: atomically exchange node->next with a version | |
1133 | * having "REMOVAL_OWNER_FLAG" set. If the returned node->next | |
1134 | * pointer did _not_ have "REMOVAL_OWNER_FLAG" set, we now own | |
1135 | * the node and win the removal race. | |
1136 | * It is interesting to note that all "add" paths are forbidden | |
1137 | * to change the next pointer starting from the point where the | |
1138 | * REMOVED_FLAG is set, so here using a read, followed by a | |
1139 | * xchg() suffice to guarantee that the xchg() will ever only | |
1140 | * set the "REMOVAL_OWNER_FLAG" (or change nothing if the flag | |
1141 | * was already set). | |
1142 | */ | |
1143 | if (!is_removal_owner(uatomic_xchg(&node->next, | |
1144 | flag_removal_owner(node->next)))) | |
1145 | return 0; | |
1146 | else | |
1147 | return -ENOENT; | |
abc490a1 | 1148 | } |
2ed95849 | 1149 | |
b7d619b0 MD |
1150 | static |
1151 | void *partition_resize_thread(void *arg) | |
1152 | { | |
1153 | struct partition_resize_work *work = arg; | |
1154 | ||
7b17c13e | 1155 | work->ht->flavor->register_thread(); |
b7d619b0 | 1156 | work->fct(work->ht, work->i, work->start, work->len); |
7b17c13e | 1157 | work->ht->flavor->unregister_thread(); |
b7d619b0 MD |
1158 | return NULL; |
1159 | } | |
1160 | ||
1161 | static | |
1162 | void partition_resize_helper(struct cds_lfht *ht, unsigned long i, | |
1163 | unsigned long len, | |
1164 | void (*fct)(struct cds_lfht *ht, unsigned long i, | |
1165 | unsigned long start, unsigned long len)) | |
1166 | { | |
e54ec2f5 | 1167 | unsigned long partition_len, start = 0; |
b7d619b0 | 1168 | struct partition_resize_work *work; |
6083a889 MD |
1169 | int thread, ret; |
1170 | unsigned long nr_threads; | |
b7d619b0 | 1171 | |
d7f3ba4c EW |
1172 | assert(nr_cpus_mask != -1); |
1173 | if (nr_cpus_mask < 0 || len < 2 * MIN_PARTITION_PER_THREAD) | |
1174 | goto fallback; | |
1175 | ||
6083a889 MD |
1176 | /* |
1177 | * Note: nr_cpus_mask + 1 is always power of 2. | |
1178 | * We spawn just the number of threads we need to satisfy the minimum | |
1179 | * partition size, up to the number of CPUs in the system. | |
1180 | */ | |
91452a6a MD |
1181 | if (nr_cpus_mask > 0) { |
1182 | nr_threads = min(nr_cpus_mask + 1, | |
1183 | len >> MIN_PARTITION_PER_THREAD_ORDER); | |
1184 | } else { | |
1185 | nr_threads = 1; | |
1186 | } | |
5bc6b66f | 1187 | partition_len = len >> cds_lfht_get_count_order_ulong(nr_threads); |
6083a889 | 1188 | work = calloc(nr_threads, sizeof(*work)); |
7c75d498 EW |
1189 | if (!work) { |
1190 | dbg_printf("error allocating for resize, single-threading\n"); | |
1191 | goto fallback; | |
1192 | } | |
6083a889 MD |
1193 | for (thread = 0; thread < nr_threads; thread++) { |
1194 | work[thread].ht = ht; | |
1195 | work[thread].i = i; | |
1196 | work[thread].len = partition_len; | |
1197 | work[thread].start = thread * partition_len; | |
1198 | work[thread].fct = fct; | |
1af6e26e | 1199 | ret = pthread_create(&(work[thread].thread_id), ht->resize_attr, |
6083a889 | 1200 | partition_resize_thread, &work[thread]); |
e54ec2f5 EW |
1201 | if (ret == EAGAIN) { |
1202 | /* | |
1203 | * Out of resources: wait and join the threads | |
1204 | * we've created, then handle leftovers. | |
1205 | */ | |
1206 | dbg_printf("error spawning for resize, single-threading\n"); | |
1207 | start = work[thread].start; | |
1208 | len -= start; | |
1209 | nr_threads = thread; | |
1210 | break; | |
1211 | } | |
b7d619b0 MD |
1212 | assert(!ret); |
1213 | } | |
6083a889 | 1214 | for (thread = 0; thread < nr_threads; thread++) { |
1af6e26e | 1215 | ret = pthread_join(work[thread].thread_id, NULL); |
b7d619b0 MD |
1216 | assert(!ret); |
1217 | } | |
1218 | free(work); | |
e54ec2f5 EW |
1219 | |
1220 | /* | |
1221 | * A pthread_create failure above will either lead in us having | |
1222 | * no threads to join or starting at a non-zero offset, | |
1223 | * fallback to single thread processing of leftovers. | |
1224 | */ | |
1225 | if (start == 0 && nr_threads > 0) | |
1226 | return; | |
7c75d498 EW |
1227 | fallback: |
1228 | ht->flavor->thread_online(); | |
e54ec2f5 | 1229 | fct(ht, i, start, len); |
7c75d498 | 1230 | ht->flavor->thread_offline(); |
b7d619b0 MD |
1231 | } |
1232 | ||
e8de508e MD |
1233 | /* |
1234 | * Holding RCU read lock to protect _cds_lfht_add against memory | |
1235 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
1236 | * problem). | |
9ee0fc9a | 1237 | * |
b7d619b0 | 1238 | * When we reach a certain length, we can split this population phase over |
9ee0fc9a MD |
1239 | * many worker threads, based on the number of CPUs available in the system. |
1240 | * This should therefore take care of not having the expand lagging behind too | |
1241 | * many concurrent insertion threads by using the scheduler's ability to | |
1ee8f000 | 1242 | * schedule bucket node population fairly with insertions. |
e8de508e | 1243 | */ |
4105056a | 1244 | static |
b7d619b0 MD |
1245 | void init_table_populate_partition(struct cds_lfht *ht, unsigned long i, |
1246 | unsigned long start, unsigned long len) | |
4105056a | 1247 | { |
9d72a73f | 1248 | unsigned long j, size = 1UL << (i - 1); |
4105056a | 1249 | |
d0d8f9aa | 1250 | assert(i > MIN_TABLE_ORDER); |
7b17c13e | 1251 | ht->flavor->read_lock(); |
9d72a73f LJ |
1252 | for (j = size + start; j < size + start + len; j++) { |
1253 | struct cds_lfht_node *new_node = bucket_at(ht, j); | |
1254 | ||
1255 | assert(j >= size && j < (size << 1)); | |
1256 | dbg_printf("init populate: order %lu index %lu hash %lu\n", | |
1257 | i, j, j); | |
1258 | new_node->reverse_hash = bit_reverse_ulong(j); | |
91a75cc5 | 1259 | _cds_lfht_add(ht, j, NULL, NULL, size, new_node, NULL, 1); |
4105056a | 1260 | } |
7b17c13e | 1261 | ht->flavor->read_unlock(); |
b7d619b0 MD |
1262 | } |
1263 | ||
1264 | static | |
1265 | void init_table_populate(struct cds_lfht *ht, unsigned long i, | |
1266 | unsigned long len) | |
1267 | { | |
b7d619b0 | 1268 | partition_resize_helper(ht, i, len, init_table_populate_partition); |
4105056a MD |
1269 | } |
1270 | ||
abc490a1 | 1271 | static |
4105056a | 1272 | void init_table(struct cds_lfht *ht, |
93d46c39 | 1273 | unsigned long first_order, unsigned long last_order) |
24365af7 | 1274 | { |
93d46c39 | 1275 | unsigned long i; |
24365af7 | 1276 | |
93d46c39 LJ |
1277 | dbg_printf("init table: first_order %lu last_order %lu\n", |
1278 | first_order, last_order); | |
d0d8f9aa | 1279 | assert(first_order > MIN_TABLE_ORDER); |
93d46c39 | 1280 | for (i = first_order; i <= last_order; i++) { |
4105056a | 1281 | unsigned long len; |
24365af7 | 1282 | |
4f6e90b7 | 1283 | len = 1UL << (i - 1); |
f0c29ed7 | 1284 | dbg_printf("init order %lu len: %lu\n", i, len); |
4d676753 MD |
1285 | |
1286 | /* Stop expand if the resize target changes under us */ | |
7b3893e4 | 1287 | if (CMM_LOAD_SHARED(ht->resize_target) < (1UL << i)) |
4d676753 MD |
1288 | break; |
1289 | ||
48f1b16d | 1290 | cds_lfht_alloc_bucket_table(ht, i); |
4105056a | 1291 | |
4105056a | 1292 | /* |
1ee8f000 LJ |
1293 | * Set all bucket nodes reverse hash values for a level and |
1294 | * link all bucket nodes into the table. | |
4105056a | 1295 | */ |
dc1da8f6 | 1296 | init_table_populate(ht, i, len); |
4105056a | 1297 | |
f9c80341 MD |
1298 | /* |
1299 | * Update table size. | |
1300 | */ | |
1301 | cmm_smp_wmb(); /* populate data before RCU size */ | |
7b3893e4 | 1302 | CMM_STORE_SHARED(ht->size, 1UL << i); |
f9c80341 | 1303 | |
4f6e90b7 | 1304 | dbg_printf("init new size: %lu\n", 1UL << i); |
4105056a MD |
1305 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
1306 | break; | |
1307 | } | |
1308 | } | |
1309 | ||
e8de508e MD |
1310 | /* |
1311 | * Holding RCU read lock to protect _cds_lfht_remove against memory | |
1312 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
1313 | * problem). | |
1314 | * For a single level, we logically remove and garbage collect each node. | |
1315 | * | |
1316 | * As a design choice, we perform logical removal and garbage collection on a | |
1317 | * node-per-node basis to simplify this algorithm. We also assume keeping good | |
1318 | * cache locality of the operation would overweight possible performance gain | |
1319 | * that could be achieved by batching garbage collection for multiple levels. | |
1320 | * However, this would have to be justified by benchmarks. | |
1321 | * | |
1322 | * Concurrent removal and add operations are helping us perform garbage | |
1323 | * collection of logically removed nodes. We guarantee that all logically | |
1324 | * removed nodes have been garbage-collected (unlinked) before call_rcu is | |
1ee8f000 | 1325 | * invoked to free a hole level of bucket nodes (after a grace period). |
e8de508e | 1326 | * |
1f67ba50 MD |
1327 | * Logical removal and garbage collection can therefore be done in batch |
1328 | * or on a node-per-node basis, as long as the guarantee above holds. | |
9ee0fc9a | 1329 | * |
b7d619b0 MD |
1330 | * When we reach a certain length, we can split this removal over many worker |
1331 | * threads, based on the number of CPUs available in the system. This should | |
1332 | * take care of not letting resize process lag behind too many concurrent | |
9ee0fc9a | 1333 | * updater threads actively inserting into the hash table. |
e8de508e | 1334 | */ |
4105056a | 1335 | static |
b7d619b0 MD |
1336 | void remove_table_partition(struct cds_lfht *ht, unsigned long i, |
1337 | unsigned long start, unsigned long len) | |
4105056a | 1338 | { |
9d72a73f | 1339 | unsigned long j, size = 1UL << (i - 1); |
4105056a | 1340 | |
d0d8f9aa | 1341 | assert(i > MIN_TABLE_ORDER); |
7b17c13e | 1342 | ht->flavor->read_lock(); |
9d72a73f | 1343 | for (j = size + start; j < size + start + len; j++) { |
2e2ce1e9 LJ |
1344 | struct cds_lfht_node *fini_bucket = bucket_at(ht, j); |
1345 | struct cds_lfht_node *parent_bucket = bucket_at(ht, j - size); | |
9d72a73f LJ |
1346 | |
1347 | assert(j >= size && j < (size << 1)); | |
1348 | dbg_printf("remove entry: order %lu index %lu hash %lu\n", | |
1349 | i, j, j); | |
2e2ce1e9 LJ |
1350 | /* Set the REMOVED_FLAG to freeze the ->next for gc */ |
1351 | uatomic_or(&fini_bucket->next, REMOVED_FLAG); | |
1352 | _cds_lfht_gc_bucket(parent_bucket, fini_bucket); | |
abc490a1 | 1353 | } |
7b17c13e | 1354 | ht->flavor->read_unlock(); |
b7d619b0 MD |
1355 | } |
1356 | ||
1357 | static | |
1358 | void remove_table(struct cds_lfht *ht, unsigned long i, unsigned long len) | |
1359 | { | |
b7d619b0 | 1360 | partition_resize_helper(ht, i, len, remove_table_partition); |
2ed95849 MD |
1361 | } |
1362 | ||
61adb337 MD |
1363 | /* |
1364 | * fini_table() is never called for first_order == 0, which is why | |
1365 | * free_by_rcu_order == 0 can be used as criterion to know if free must | |
1366 | * be called. | |
1367 | */ | |
1475579c | 1368 | static |
4105056a | 1369 | void fini_table(struct cds_lfht *ht, |
93d46c39 | 1370 | unsigned long first_order, unsigned long last_order) |
1475579c | 1371 | { |
93d46c39 | 1372 | long i; |
48f1b16d | 1373 | unsigned long free_by_rcu_order = 0; |
1475579c | 1374 | |
93d46c39 LJ |
1375 | dbg_printf("fini table: first_order %lu last_order %lu\n", |
1376 | first_order, last_order); | |
d0d8f9aa | 1377 | assert(first_order > MIN_TABLE_ORDER); |
93d46c39 | 1378 | for (i = last_order; i >= first_order; i--) { |
4105056a | 1379 | unsigned long len; |
1475579c | 1380 | |
4f6e90b7 | 1381 | len = 1UL << (i - 1); |
e15df1cc | 1382 | dbg_printf("fini order %ld len: %lu\n", i, len); |
4105056a | 1383 | |
4d676753 | 1384 | /* Stop shrink if the resize target changes under us */ |
7b3893e4 | 1385 | if (CMM_LOAD_SHARED(ht->resize_target) > (1UL << (i - 1))) |
4d676753 MD |
1386 | break; |
1387 | ||
1388 | cmm_smp_wmb(); /* populate data before RCU size */ | |
7b3893e4 | 1389 | CMM_STORE_SHARED(ht->size, 1UL << (i - 1)); |
4d676753 MD |
1390 | |
1391 | /* | |
1392 | * We need to wait for all add operations to reach Q.S. (and | |
1393 | * thus use the new table for lookups) before we can start | |
1ee8f000 | 1394 | * releasing the old bucket nodes. Otherwise their lookup will |
4d676753 MD |
1395 | * return a logically removed node as insert position. |
1396 | */ | |
7b17c13e | 1397 | ht->flavor->update_synchronize_rcu(); |
48f1b16d LJ |
1398 | if (free_by_rcu_order) |
1399 | cds_lfht_free_bucket_table(ht, free_by_rcu_order); | |
4d676753 | 1400 | |
21263e21 | 1401 | /* |
1ee8f000 LJ |
1402 | * Set "removed" flag in bucket nodes about to be removed. |
1403 | * Unlink all now-logically-removed bucket node pointers. | |
4105056a MD |
1404 | * Concurrent add/remove operation are helping us doing |
1405 | * the gc. | |
21263e21 | 1406 | */ |
4105056a MD |
1407 | remove_table(ht, i, len); |
1408 | ||
48f1b16d | 1409 | free_by_rcu_order = i; |
4105056a MD |
1410 | |
1411 | dbg_printf("fini new size: %lu\n", 1UL << i); | |
1475579c MD |
1412 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
1413 | break; | |
1414 | } | |
0d14ceb2 | 1415 | |
48f1b16d | 1416 | if (free_by_rcu_order) { |
7b17c13e | 1417 | ht->flavor->update_synchronize_rcu(); |
48f1b16d | 1418 | cds_lfht_free_bucket_table(ht, free_by_rcu_order); |
0d14ceb2 | 1419 | } |
1475579c MD |
1420 | } |
1421 | ||
ff0d69de | 1422 | static |
1ee8f000 | 1423 | void cds_lfht_create_bucket(struct cds_lfht *ht, unsigned long size) |
ff0d69de | 1424 | { |
04db56f8 | 1425 | struct cds_lfht_node *prev, *node; |
9d72a73f | 1426 | unsigned long order, len, i; |
ff0d69de | 1427 | |
48f1b16d | 1428 | cds_lfht_alloc_bucket_table(ht, 0); |
ff0d69de | 1429 | |
9d72a73f LJ |
1430 | dbg_printf("create bucket: order 0 index 0 hash 0\n"); |
1431 | node = bucket_at(ht, 0); | |
1432 | node->next = flag_bucket(get_end()); | |
1433 | node->reverse_hash = 0; | |
ff0d69de | 1434 | |
5bc6b66f | 1435 | for (order = 1; order < cds_lfht_get_count_order_ulong(size) + 1; order++) { |
ff0d69de | 1436 | len = 1UL << (order - 1); |
48f1b16d | 1437 | cds_lfht_alloc_bucket_table(ht, order); |
ff0d69de | 1438 | |
9d72a73f LJ |
1439 | for (i = 0; i < len; i++) { |
1440 | /* | |
1441 | * Now, we are trying to init the node with the | |
1442 | * hash=(len+i) (which is also a bucket with the | |
1443 | * index=(len+i)) and insert it into the hash table, | |
1444 | * so this node has to be inserted after the bucket | |
1445 | * with the index=(len+i)&(len-1)=i. And because there | |
1446 | * is no other non-bucket node nor bucket node with | |
1447 | * larger index/hash inserted, so the bucket node | |
1448 | * being inserted should be inserted directly linked | |
1449 | * after the bucket node with index=i. | |
1450 | */ | |
1451 | prev = bucket_at(ht, i); | |
1452 | node = bucket_at(ht, len + i); | |
ff0d69de | 1453 | |
1ee8f000 | 1454 | dbg_printf("create bucket: order %lu index %lu hash %lu\n", |
9d72a73f LJ |
1455 | order, len + i, len + i); |
1456 | node->reverse_hash = bit_reverse_ulong(len + i); | |
1457 | ||
1458 | /* insert after prev */ | |
1459 | assert(is_bucket(prev->next)); | |
ff0d69de | 1460 | node->next = prev->next; |
1ee8f000 | 1461 | prev->next = flag_bucket(node); |
ff0d69de LJ |
1462 | } |
1463 | } | |
1464 | } | |
1465 | ||
0422d92c | 1466 | struct cds_lfht *_cds_lfht_new(unsigned long init_size, |
0722081a | 1467 | unsigned long min_nr_alloc_buckets, |
747d725c | 1468 | unsigned long max_nr_buckets, |
b8af5011 | 1469 | int flags, |
0b6aa001 | 1470 | const struct cds_lfht_mm_type *mm, |
7b17c13e | 1471 | const struct rcu_flavor_struct *flavor, |
b7d619b0 | 1472 | pthread_attr_t *attr) |
abc490a1 | 1473 | { |
14044b37 | 1474 | struct cds_lfht *ht; |
24365af7 | 1475 | unsigned long order; |
abc490a1 | 1476 | |
0722081a LJ |
1477 | /* min_nr_alloc_buckets must be power of two */ |
1478 | if (!min_nr_alloc_buckets || (min_nr_alloc_buckets & (min_nr_alloc_buckets - 1))) | |
5488222b | 1479 | return NULL; |
747d725c | 1480 | |
8129be4e | 1481 | /* init_size must be power of two */ |
5488222b | 1482 | if (!init_size || (init_size & (init_size - 1))) |
8129be4e | 1483 | return NULL; |
747d725c | 1484 | |
c1888f3a MD |
1485 | /* |
1486 | * Memory management plugin default. | |
1487 | */ | |
1488 | if (!mm) { | |
5a2141a7 MD |
1489 | if (CAA_BITS_PER_LONG > 32 |
1490 | && max_nr_buckets | |
c1888f3a MD |
1491 | && max_nr_buckets <= (1ULL << 32)) { |
1492 | /* | |
1493 | * For 64-bit architectures, with max number of | |
1494 | * buckets small enough not to use the entire | |
1495 | * 64-bit memory mapping space (and allowing a | |
1496 | * fair number of hash table instances), use the | |
1497 | * mmap allocator, which is faster than the | |
1498 | * order allocator. | |
1499 | */ | |
1500 | mm = &cds_lfht_mm_mmap; | |
1501 | } else { | |
1502 | /* | |
1503 | * The fallback is to use the order allocator. | |
1504 | */ | |
1505 | mm = &cds_lfht_mm_order; | |
1506 | } | |
1507 | } | |
1508 | ||
0b6aa001 LJ |
1509 | /* max_nr_buckets == 0 for order based mm means infinite */ |
1510 | if (mm == &cds_lfht_mm_order && !max_nr_buckets) | |
747d725c LJ |
1511 | max_nr_buckets = 1UL << (MAX_TABLE_ORDER - 1); |
1512 | ||
1513 | /* max_nr_buckets must be power of two */ | |
1514 | if (!max_nr_buckets || (max_nr_buckets & (max_nr_buckets - 1))) | |
1515 | return NULL; | |
1516 | ||
0722081a | 1517 | min_nr_alloc_buckets = max(min_nr_alloc_buckets, MIN_TABLE_SIZE); |
d0d8f9aa | 1518 | init_size = max(init_size, MIN_TABLE_SIZE); |
747d725c LJ |
1519 | max_nr_buckets = max(max_nr_buckets, min_nr_alloc_buckets); |
1520 | init_size = min(init_size, max_nr_buckets); | |
0b6aa001 LJ |
1521 | |
1522 | ht = mm->alloc_cds_lfht(min_nr_alloc_buckets, max_nr_buckets); | |
b7d619b0 | 1523 | assert(ht); |
0b6aa001 LJ |
1524 | assert(ht->mm == mm); |
1525 | assert(ht->bucket_at == mm->bucket_at); | |
1526 | ||
b5d6b20f | 1527 | ht->flags = flags; |
7b17c13e | 1528 | ht->flavor = flavor; |
b7d619b0 | 1529 | ht->resize_attr = attr; |
5afadd12 | 1530 | alloc_split_items_count(ht); |
abc490a1 MD |
1531 | /* this mutex should not nest in read-side C.S. */ |
1532 | pthread_mutex_init(&ht->resize_mutex, NULL); | |
5bc6b66f | 1533 | order = cds_lfht_get_count_order_ulong(init_size); |
7b3893e4 | 1534 | ht->resize_target = 1UL << order; |
1ee8f000 | 1535 | cds_lfht_create_bucket(ht, 1UL << order); |
7b3893e4 | 1536 | ht->size = 1UL << order; |
abc490a1 MD |
1537 | return ht; |
1538 | } | |
1539 | ||
6f554439 | 1540 | void cds_lfht_lookup(struct cds_lfht *ht, unsigned long hash, |
996ff57c | 1541 | cds_lfht_match_fct match, const void *key, |
6f554439 | 1542 | struct cds_lfht_iter *iter) |
2ed95849 | 1543 | { |
04db56f8 | 1544 | struct cds_lfht_node *node, *next, *bucket; |
0422d92c | 1545 | unsigned long reverse_hash, size; |
2ed95849 | 1546 | |
abc490a1 | 1547 | reverse_hash = bit_reverse_ulong(hash); |
464a1ec9 | 1548 | |
7b3893e4 | 1549 | size = rcu_dereference(ht->size); |
04db56f8 | 1550 | bucket = lookup_bucket(ht, size, hash); |
1ee8f000 | 1551 | /* We can always skip the bucket node initially */ |
04db56f8 | 1552 | node = rcu_dereference(bucket->next); |
bb7b2f26 | 1553 | node = clear_flag(node); |
2ed95849 | 1554 | for (;;) { |
8ed51e04 | 1555 | if (caa_unlikely(is_end(node))) { |
96ad1112 | 1556 | node = next = NULL; |
abc490a1 | 1557 | break; |
bb7b2f26 | 1558 | } |
04db56f8 | 1559 | if (caa_unlikely(node->reverse_hash > reverse_hash)) { |
96ad1112 | 1560 | node = next = NULL; |
abc490a1 | 1561 | break; |
2ed95849 | 1562 | } |
04db56f8 | 1563 | next = rcu_dereference(node->next); |
7f52427b | 1564 | assert(node == clear_flag(node)); |
8ed51e04 | 1565 | if (caa_likely(!is_removed(next)) |
1ee8f000 | 1566 | && !is_bucket(next) |
04db56f8 | 1567 | && node->reverse_hash == reverse_hash |
0422d92c | 1568 | && caa_likely(match(node, key))) { |
273399de | 1569 | break; |
2ed95849 | 1570 | } |
1b81fe1a | 1571 | node = clear_flag(next); |
2ed95849 | 1572 | } |
a85eff52 | 1573 | assert(!node || !is_bucket(CMM_LOAD_SHARED(node->next))); |
adc0de68 MD |
1574 | iter->node = node; |
1575 | iter->next = next; | |
abc490a1 | 1576 | } |
e0ba718a | 1577 | |
0422d92c | 1578 | void cds_lfht_next_duplicate(struct cds_lfht *ht, cds_lfht_match_fct match, |
996ff57c | 1579 | const void *key, struct cds_lfht_iter *iter) |
a481e5ff | 1580 | { |
adc0de68 | 1581 | struct cds_lfht_node *node, *next; |
a481e5ff | 1582 | unsigned long reverse_hash; |
a481e5ff | 1583 | |
adc0de68 | 1584 | node = iter->node; |
04db56f8 | 1585 | reverse_hash = node->reverse_hash; |
adc0de68 | 1586 | next = iter->next; |
a481e5ff MD |
1587 | node = clear_flag(next); |
1588 | ||
1589 | for (;;) { | |
8ed51e04 | 1590 | if (caa_unlikely(is_end(node))) { |
96ad1112 | 1591 | node = next = NULL; |
a481e5ff | 1592 | break; |
bb7b2f26 | 1593 | } |
04db56f8 | 1594 | if (caa_unlikely(node->reverse_hash > reverse_hash)) { |
96ad1112 | 1595 | node = next = NULL; |
a481e5ff MD |
1596 | break; |
1597 | } | |
04db56f8 | 1598 | next = rcu_dereference(node->next); |
8ed51e04 | 1599 | if (caa_likely(!is_removed(next)) |
1ee8f000 | 1600 | && !is_bucket(next) |
04db56f8 | 1601 | && caa_likely(match(node, key))) { |
a481e5ff MD |
1602 | break; |
1603 | } | |
1604 | node = clear_flag(next); | |
1605 | } | |
a85eff52 | 1606 | assert(!node || !is_bucket(CMM_LOAD_SHARED(node->next))); |
adc0de68 MD |
1607 | iter->node = node; |
1608 | iter->next = next; | |
a481e5ff MD |
1609 | } |
1610 | ||
4e9b9fbf MD |
1611 | void cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_iter *iter) |
1612 | { | |
1613 | struct cds_lfht_node *node, *next; | |
1614 | ||
853395e1 | 1615 | node = clear_flag(iter->next); |
4e9b9fbf | 1616 | for (;;) { |
8ed51e04 | 1617 | if (caa_unlikely(is_end(node))) { |
4e9b9fbf MD |
1618 | node = next = NULL; |
1619 | break; | |
1620 | } | |
04db56f8 | 1621 | next = rcu_dereference(node->next); |
8ed51e04 | 1622 | if (caa_likely(!is_removed(next)) |
1ee8f000 | 1623 | && !is_bucket(next)) { |
4e9b9fbf MD |
1624 | break; |
1625 | } | |
1626 | node = clear_flag(next); | |
1627 | } | |
a85eff52 | 1628 | assert(!node || !is_bucket(CMM_LOAD_SHARED(node->next))); |
4e9b9fbf MD |
1629 | iter->node = node; |
1630 | iter->next = next; | |
1631 | } | |
1632 | ||
1633 | void cds_lfht_first(struct cds_lfht *ht, struct cds_lfht_iter *iter) | |
1634 | { | |
4e9b9fbf | 1635 | /* |
1ee8f000 | 1636 | * Get next after first bucket node. The first bucket node is the |
4e9b9fbf MD |
1637 | * first node of the linked list. |
1638 | */ | |
9d72a73f | 1639 | iter->next = bucket_at(ht, 0)->next; |
4e9b9fbf MD |
1640 | cds_lfht_next(ht, iter); |
1641 | } | |
1642 | ||
0422d92c MD |
1643 | void cds_lfht_add(struct cds_lfht *ht, unsigned long hash, |
1644 | struct cds_lfht_node *node) | |
abc490a1 | 1645 | { |
0422d92c | 1646 | unsigned long size; |
ab7d5fc6 | 1647 | |
709bacf9 | 1648 | node->reverse_hash = bit_reverse_ulong(hash); |
7b3893e4 | 1649 | size = rcu_dereference(ht->size); |
91a75cc5 | 1650 | _cds_lfht_add(ht, hash, NULL, NULL, size, node, NULL, 0); |
14360f1c | 1651 | ht_count_add(ht, size, hash); |
3eca1b8c MD |
1652 | } |
1653 | ||
14044b37 | 1654 | struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, |
6f554439 | 1655 | unsigned long hash, |
0422d92c | 1656 | cds_lfht_match_fct match, |
996ff57c | 1657 | const void *key, |
48ed1c18 | 1658 | struct cds_lfht_node *node) |
3eca1b8c | 1659 | { |
0422d92c | 1660 | unsigned long size; |
83beee94 | 1661 | struct cds_lfht_iter iter; |
3eca1b8c | 1662 | |
709bacf9 | 1663 | node->reverse_hash = bit_reverse_ulong(hash); |
7b3893e4 | 1664 | size = rcu_dereference(ht->size); |
91a75cc5 | 1665 | _cds_lfht_add(ht, hash, match, key, size, node, &iter, 0); |
83beee94 | 1666 | if (iter.node == node) |
14360f1c | 1667 | ht_count_add(ht, size, hash); |
83beee94 | 1668 | return iter.node; |
2ed95849 MD |
1669 | } |
1670 | ||
9357c415 | 1671 | struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht, |
6f554439 | 1672 | unsigned long hash, |
0422d92c | 1673 | cds_lfht_match_fct match, |
996ff57c | 1674 | const void *key, |
48ed1c18 MD |
1675 | struct cds_lfht_node *node) |
1676 | { | |
0422d92c | 1677 | unsigned long size; |
83beee94 | 1678 | struct cds_lfht_iter iter; |
48ed1c18 | 1679 | |
709bacf9 | 1680 | node->reverse_hash = bit_reverse_ulong(hash); |
7b3893e4 | 1681 | size = rcu_dereference(ht->size); |
83beee94 | 1682 | for (;;) { |
91a75cc5 | 1683 | _cds_lfht_add(ht, hash, match, key, size, node, &iter, 0); |
83beee94 | 1684 | if (iter.node == node) { |
14360f1c | 1685 | ht_count_add(ht, size, hash); |
83beee94 MD |
1686 | return NULL; |
1687 | } | |
1688 | ||
1689 | if (!_cds_lfht_replace(ht, size, iter.node, iter.next, node)) | |
1690 | return iter.node; | |
1691 | } | |
48ed1c18 MD |
1692 | } |
1693 | ||
2e79c445 MD |
1694 | int cds_lfht_replace(struct cds_lfht *ht, |
1695 | struct cds_lfht_iter *old_iter, | |
1696 | unsigned long hash, | |
1697 | cds_lfht_match_fct match, | |
1698 | const void *key, | |
9357c415 MD |
1699 | struct cds_lfht_node *new_node) |
1700 | { | |
1701 | unsigned long size; | |
1702 | ||
709bacf9 | 1703 | new_node->reverse_hash = bit_reverse_ulong(hash); |
2e79c445 MD |
1704 | if (!old_iter->node) |
1705 | return -ENOENT; | |
1706 | if (caa_unlikely(old_iter->node->reverse_hash != new_node->reverse_hash)) | |
1707 | return -EINVAL; | |
1708 | if (caa_unlikely(!match(old_iter->node, key))) | |
1709 | return -EINVAL; | |
7b3893e4 | 1710 | size = rcu_dereference(ht->size); |
9357c415 MD |
1711 | return _cds_lfht_replace(ht, size, old_iter->node, old_iter->next, |
1712 | new_node); | |
1713 | } | |
1714 | ||
bc8c3c74 | 1715 | int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_node *node) |
2ed95849 | 1716 | { |
95bc7fb9 | 1717 | unsigned long size; |
df44348d | 1718 | int ret; |
abc490a1 | 1719 | |
7b3893e4 | 1720 | size = rcu_dereference(ht->size); |
bc8c3c74 | 1721 | ret = _cds_lfht_del(ht, size, node); |
14360f1c | 1722 | if (!ret) { |
95bc7fb9 MD |
1723 | unsigned long hash; |
1724 | ||
bc8c3c74 | 1725 | hash = bit_reverse_ulong(node->reverse_hash); |
14360f1c LJ |
1726 | ht_count_del(ht, size, hash); |
1727 | } | |
df44348d | 1728 | return ret; |
2ed95849 | 1729 | } |
ab7d5fc6 | 1730 | |
df55172a MD |
1731 | int cds_lfht_is_node_deleted(struct cds_lfht_node *node) |
1732 | { | |
a85eff52 | 1733 | return is_removed(CMM_LOAD_SHARED(node->next)); |
df55172a MD |
1734 | } |
1735 | ||
abc490a1 | 1736 | static |
1ee8f000 | 1737 | int cds_lfht_delete_bucket(struct cds_lfht *ht) |
674f7a69 | 1738 | { |
14044b37 | 1739 | struct cds_lfht_node *node; |
4105056a | 1740 | unsigned long order, i, size; |
674f7a69 | 1741 | |
abc490a1 | 1742 | /* Check that the table is empty */ |
9d72a73f | 1743 | node = bucket_at(ht, 0); |
abc490a1 | 1744 | do { |
04db56f8 | 1745 | node = clear_flag(node)->next; |
1ee8f000 | 1746 | if (!is_bucket(node)) |
abc490a1 | 1747 | return -EPERM; |
273399de | 1748 | assert(!is_removed(node)); |
2f943cd7 | 1749 | assert(!is_removal_owner(node)); |
bb7b2f26 | 1750 | } while (!is_end(node)); |
4105056a MD |
1751 | /* |
1752 | * size accessed without rcu_dereference because hash table is | |
1753 | * being destroyed. | |
1754 | */ | |
7b3893e4 | 1755 | size = ht->size; |
1f67ba50 | 1756 | /* Internal sanity check: all nodes left should be buckets */ |
48f1b16d LJ |
1757 | for (i = 0; i < size; i++) { |
1758 | node = bucket_at(ht, i); | |
1759 | dbg_printf("delete bucket: index %lu expected hash %lu hash %lu\n", | |
1760 | i, i, bit_reverse_ulong(node->reverse_hash)); | |
1761 | assert(is_bucket(node->next)); | |
1762 | } | |
24365af7 | 1763 | |
5bc6b66f | 1764 | for (order = cds_lfht_get_count_order_ulong(size); (long)order >= 0; order--) |
48f1b16d | 1765 | cds_lfht_free_bucket_table(ht, order); |
5488222b | 1766 | |
abc490a1 | 1767 | return 0; |
674f7a69 MD |
1768 | } |
1769 | ||
1770 | /* | |
1771 | * Should only be called when no more concurrent readers nor writers can | |
1772 | * possibly access the table. | |
1773 | */ | |
b7d619b0 | 1774 | int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr) |
674f7a69 | 1775 | { |
a1e5e232 | 1776 | int ret, was_online; |
5e28c532 | 1777 | |
848d4088 | 1778 | /* Wait for in-flight resize operations to complete */ |
24953e08 MD |
1779 | _CMM_STORE_SHARED(ht->in_progress_destroy, 1); |
1780 | cmm_smp_mb(); /* Store destroy before load resize */ | |
a1e5e232 MD |
1781 | was_online = ht->flavor->read_ongoing(); |
1782 | if (was_online) | |
1783 | ht->flavor->thread_offline(); | |
10e68472 MD |
1784 | /* Calling with RCU read-side held is an error. */ |
1785 | if (ht->flavor->read_ongoing()) { | |
1786 | ret = -EINVAL; | |
1787 | if (was_online) | |
1788 | ht->flavor->thread_online(); | |
1789 | goto end; | |
1790 | } | |
848d4088 MD |
1791 | while (uatomic_read(&ht->in_progress_resize)) |
1792 | poll(NULL, 0, 100); /* wait for 100ms */ | |
a1e5e232 MD |
1793 | if (was_online) |
1794 | ht->flavor->thread_online(); | |
1ee8f000 | 1795 | ret = cds_lfht_delete_bucket(ht); |
abc490a1 MD |
1796 | if (ret) |
1797 | return ret; | |
5afadd12 | 1798 | free_split_items_count(ht); |
b7d619b0 MD |
1799 | if (attr) |
1800 | *attr = ht->resize_attr; | |
98808fb1 | 1801 | poison_free(ht); |
10e68472 | 1802 | end: |
5e28c532 | 1803 | return ret; |
674f7a69 MD |
1804 | } |
1805 | ||
14044b37 | 1806 | void cds_lfht_count_nodes(struct cds_lfht *ht, |
d933dd0e | 1807 | long *approx_before, |
273399de | 1808 | unsigned long *count, |
d933dd0e | 1809 | long *approx_after) |
273399de | 1810 | { |
14044b37 | 1811 | struct cds_lfht_node *node, *next; |
caf3653d | 1812 | unsigned long nr_bucket = 0, nr_removed = 0; |
273399de | 1813 | |
7ed7682f | 1814 | *approx_before = 0; |
5afadd12 | 1815 | if (ht->split_count) { |
973e5e1b MD |
1816 | int i; |
1817 | ||
4c42f1b8 LJ |
1818 | for (i = 0; i < split_count_mask + 1; i++) { |
1819 | *approx_before += uatomic_read(&ht->split_count[i].add); | |
1820 | *approx_before -= uatomic_read(&ht->split_count[i].del); | |
973e5e1b MD |
1821 | } |
1822 | } | |
1823 | ||
273399de | 1824 | *count = 0; |
273399de | 1825 | |
1ee8f000 | 1826 | /* Count non-bucket nodes in the table */ |
9d72a73f | 1827 | node = bucket_at(ht, 0); |
273399de | 1828 | do { |
04db56f8 | 1829 | next = rcu_dereference(node->next); |
b198f0fd | 1830 | if (is_removed(next)) { |
1ee8f000 | 1831 | if (!is_bucket(next)) |
caf3653d | 1832 | (nr_removed)++; |
973e5e1b | 1833 | else |
1ee8f000 LJ |
1834 | (nr_bucket)++; |
1835 | } else if (!is_bucket(next)) | |
273399de | 1836 | (*count)++; |
24365af7 | 1837 | else |
1ee8f000 | 1838 | (nr_bucket)++; |
273399de | 1839 | node = clear_flag(next); |
bb7b2f26 | 1840 | } while (!is_end(node)); |
caf3653d | 1841 | dbg_printf("number of logically removed nodes: %lu\n", nr_removed); |
1ee8f000 | 1842 | dbg_printf("number of bucket nodes: %lu\n", nr_bucket); |
7ed7682f | 1843 | *approx_after = 0; |
5afadd12 | 1844 | if (ht->split_count) { |
973e5e1b MD |
1845 | int i; |
1846 | ||
4c42f1b8 LJ |
1847 | for (i = 0; i < split_count_mask + 1; i++) { |
1848 | *approx_after += uatomic_read(&ht->split_count[i].add); | |
1849 | *approx_after -= uatomic_read(&ht->split_count[i].del); | |
973e5e1b MD |
1850 | } |
1851 | } | |
273399de MD |
1852 | } |
1853 | ||
1475579c | 1854 | /* called with resize mutex held */ |
abc490a1 | 1855 | static |
4105056a | 1856 | void _do_cds_lfht_grow(struct cds_lfht *ht, |
1475579c | 1857 | unsigned long old_size, unsigned long new_size) |
abc490a1 | 1858 | { |
1475579c | 1859 | unsigned long old_order, new_order; |
1475579c | 1860 | |
5bc6b66f MD |
1861 | old_order = cds_lfht_get_count_order_ulong(old_size); |
1862 | new_order = cds_lfht_get_count_order_ulong(new_size); | |
1a401918 LJ |
1863 | dbg_printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", |
1864 | old_size, old_order, new_size, new_order); | |
1475579c | 1865 | assert(new_size > old_size); |
93d46c39 | 1866 | init_table(ht, old_order + 1, new_order); |
abc490a1 MD |
1867 | } |
1868 | ||
1869 | /* called with resize mutex held */ | |
1870 | static | |
4105056a | 1871 | void _do_cds_lfht_shrink(struct cds_lfht *ht, |
1475579c | 1872 | unsigned long old_size, unsigned long new_size) |
464a1ec9 | 1873 | { |
1475579c | 1874 | unsigned long old_order, new_order; |
464a1ec9 | 1875 | |
d0d8f9aa | 1876 | new_size = max(new_size, MIN_TABLE_SIZE); |
5bc6b66f MD |
1877 | old_order = cds_lfht_get_count_order_ulong(old_size); |
1878 | new_order = cds_lfht_get_count_order_ulong(new_size); | |
1a401918 LJ |
1879 | dbg_printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", |
1880 | old_size, old_order, new_size, new_order); | |
1475579c | 1881 | assert(new_size < old_size); |
1475579c | 1882 | |
1ee8f000 | 1883 | /* Remove and unlink all bucket nodes to remove. */ |
93d46c39 | 1884 | fini_table(ht, new_order + 1, old_order); |
464a1ec9 MD |
1885 | } |
1886 | ||
1475579c MD |
1887 | |
1888 | /* called with resize mutex held */ | |
1889 | static | |
1890 | void _do_cds_lfht_resize(struct cds_lfht *ht) | |
1891 | { | |
1892 | unsigned long new_size, old_size; | |
4105056a MD |
1893 | |
1894 | /* | |
1895 | * Resize table, re-do if the target size has changed under us. | |
1896 | */ | |
1897 | do { | |
d2be3620 MD |
1898 | assert(uatomic_read(&ht->in_progress_resize)); |
1899 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
1900 | break; | |
7b3893e4 LJ |
1901 | ht->resize_initiated = 1; |
1902 | old_size = ht->size; | |
1903 | new_size = CMM_LOAD_SHARED(ht->resize_target); | |
4105056a MD |
1904 | if (old_size < new_size) |
1905 | _do_cds_lfht_grow(ht, old_size, new_size); | |
1906 | else if (old_size > new_size) | |
1907 | _do_cds_lfht_shrink(ht, old_size, new_size); | |
7b3893e4 | 1908 | ht->resize_initiated = 0; |
4105056a MD |
1909 | /* write resize_initiated before read resize_target */ |
1910 | cmm_smp_mb(); | |
7b3893e4 | 1911 | } while (ht->size != CMM_LOAD_SHARED(ht->resize_target)); |
1475579c MD |
1912 | } |
1913 | ||
abc490a1 | 1914 | static |
ab65b890 | 1915 | unsigned long resize_target_grow(struct cds_lfht *ht, unsigned long new_size) |
464a1ec9 | 1916 | { |
7b3893e4 | 1917 | return _uatomic_xchg_monotonic_increase(&ht->resize_target, new_size); |
464a1ec9 MD |
1918 | } |
1919 | ||
1475579c | 1920 | static |
4105056a | 1921 | void resize_target_update_count(struct cds_lfht *ht, |
b8af5011 | 1922 | unsigned long count) |
1475579c | 1923 | { |
d0d8f9aa | 1924 | count = max(count, MIN_TABLE_SIZE); |
747d725c | 1925 | count = min(count, ht->max_nr_buckets); |
7b3893e4 | 1926 | uatomic_set(&ht->resize_target, count); |
1475579c MD |
1927 | } |
1928 | ||
1929 | void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size) | |
464a1ec9 | 1930 | { |
a1e5e232 MD |
1931 | int was_online; |
1932 | ||
a1e5e232 MD |
1933 | was_online = ht->flavor->read_ongoing(); |
1934 | if (was_online) | |
1935 | ht->flavor->thread_offline(); | |
10e68472 MD |
1936 | /* Calling with RCU read-side held is an error. */ |
1937 | if (ht->flavor->read_ongoing()) { | |
1938 | static int print_once; | |
1939 | ||
1940 | if (!CMM_LOAD_SHARED(print_once)) | |
1941 | fprintf(stderr, "[error] rculfhash: cds_lfht_resize " | |
1942 | "called with RCU read-side lock held.\n"); | |
1943 | CMM_STORE_SHARED(print_once, 1); | |
1944 | assert(0); | |
1945 | goto end; | |
1946 | } | |
1947 | resize_target_update_count(ht, new_size); | |
1948 | CMM_STORE_SHARED(ht->resize_initiated, 1); | |
1475579c MD |
1949 | pthread_mutex_lock(&ht->resize_mutex); |
1950 | _do_cds_lfht_resize(ht); | |
1951 | pthread_mutex_unlock(&ht->resize_mutex); | |
10e68472 | 1952 | end: |
a1e5e232 MD |
1953 | if (was_online) |
1954 | ht->flavor->thread_online(); | |
abc490a1 | 1955 | } |
464a1ec9 | 1956 | |
abc490a1 MD |
1957 | static |
1958 | void do_resize_cb(struct rcu_head *head) | |
1959 | { | |
1960 | struct rcu_resize_work *work = | |
1961 | caa_container_of(head, struct rcu_resize_work, head); | |
14044b37 | 1962 | struct cds_lfht *ht = work->ht; |
abc490a1 | 1963 | |
7b17c13e | 1964 | ht->flavor->thread_offline(); |
abc490a1 | 1965 | pthread_mutex_lock(&ht->resize_mutex); |
14044b37 | 1966 | _do_cds_lfht_resize(ht); |
abc490a1 | 1967 | pthread_mutex_unlock(&ht->resize_mutex); |
7b17c13e | 1968 | ht->flavor->thread_online(); |
98808fb1 | 1969 | poison_free(work); |
848d4088 MD |
1970 | cmm_smp_mb(); /* finish resize before decrement */ |
1971 | uatomic_dec(&ht->in_progress_resize); | |
464a1ec9 MD |
1972 | } |
1973 | ||
abc490a1 | 1974 | static |
f1f119ee | 1975 | void __cds_lfht_resize_lazy_launch(struct cds_lfht *ht) |
ab7d5fc6 | 1976 | { |
abc490a1 MD |
1977 | struct rcu_resize_work *work; |
1978 | ||
4105056a MD |
1979 | /* Store resize_target before read resize_initiated */ |
1980 | cmm_smp_mb(); | |
7b3893e4 | 1981 | if (!CMM_LOAD_SHARED(ht->resize_initiated)) { |
848d4088 | 1982 | uatomic_inc(&ht->in_progress_resize); |
59290e9d | 1983 | cmm_smp_mb(); /* increment resize count before load destroy */ |
ed35e6d8 MD |
1984 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) { |
1985 | uatomic_dec(&ht->in_progress_resize); | |
59290e9d | 1986 | return; |
ed35e6d8 | 1987 | } |
f9830efd | 1988 | work = malloc(sizeof(*work)); |
741f378e MD |
1989 | if (work == NULL) { |
1990 | dbg_printf("error allocating resize work, bailing out\n"); | |
1991 | uatomic_dec(&ht->in_progress_resize); | |
1992 | return; | |
1993 | } | |
f9830efd | 1994 | work->ht = ht; |
7b17c13e | 1995 | ht->flavor->update_call_rcu(&work->head, do_resize_cb); |
7b3893e4 | 1996 | CMM_STORE_SHARED(ht->resize_initiated, 1); |
f9830efd | 1997 | } |
ab7d5fc6 | 1998 | } |
3171717f | 1999 | |
f1f119ee LJ |
2000 | static |
2001 | void cds_lfht_resize_lazy_grow(struct cds_lfht *ht, unsigned long size, int growth) | |
2002 | { | |
2003 | unsigned long target_size = size << growth; | |
2004 | ||
747d725c | 2005 | target_size = min(target_size, ht->max_nr_buckets); |
f1f119ee LJ |
2006 | if (resize_target_grow(ht, target_size) >= target_size) |
2007 | return; | |
2008 | ||
2009 | __cds_lfht_resize_lazy_launch(ht); | |
2010 | } | |
2011 | ||
89bb121d LJ |
2012 | /* |
2013 | * We favor grow operations over shrink. A shrink operation never occurs | |
2014 | * if a grow operation is queued for lazy execution. A grow operation | |
2015 | * cancels any pending shrink lazy execution. | |
2016 | */ | |
3171717f | 2017 | static |
4105056a | 2018 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, |
3171717f MD |
2019 | unsigned long count) |
2020 | { | |
b8af5011 MD |
2021 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) |
2022 | return; | |
d0d8f9aa | 2023 | count = max(count, MIN_TABLE_SIZE); |
747d725c | 2024 | count = min(count, ht->max_nr_buckets); |
89bb121d LJ |
2025 | if (count == size) |
2026 | return; /* Already the right size, no resize needed */ | |
2027 | if (count > size) { /* lazy grow */ | |
2028 | if (resize_target_grow(ht, count) >= count) | |
2029 | return; | |
2030 | } else { /* lazy shrink */ | |
2031 | for (;;) { | |
2032 | unsigned long s; | |
2033 | ||
7b3893e4 | 2034 | s = uatomic_cmpxchg(&ht->resize_target, size, count); |
89bb121d LJ |
2035 | if (s == size) |
2036 | break; /* no resize needed */ | |
2037 | if (s > size) | |
2038 | return; /* growing is/(was just) in progress */ | |
2039 | if (s <= count) | |
2040 | return; /* some other thread do shrink */ | |
2041 | size = s; | |
2042 | } | |
2043 | } | |
f1f119ee | 2044 | __cds_lfht_resize_lazy_launch(ht); |
3171717f | 2045 | } |