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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 MD |
258 | #define _LGPL_SOURCE |
259 | #include <stdlib.h> | |
e0ba718a MD |
260 | #include <errno.h> |
261 | #include <assert.h> | |
262 | #include <stdio.h> | |
abc490a1 | 263 | #include <stdint.h> |
f000907d | 264 | #include <string.h> |
125f41db | 265 | #include <sched.h> |
95747f9e | 266 | #include <unistd.h> |
e0ba718a | 267 | |
a47dd11c | 268 | #include "compat-getcpu.h" |
95747f9e | 269 | #include <urcu-pointer.h> |
abc490a1 | 270 | #include <urcu-call-rcu.h> |
7b17c13e | 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> |
0b6aa001 | 276 | #include <rculfhash-internal.h> |
5e28c532 | 277 | #include <stdio.h> |
464a1ec9 | 278 | #include <pthread.h> |
44395fb7 | 279 | |
f8994aee | 280 | /* |
4c42f1b8 | 281 | * Split-counters lazily update the global counter each 1024 |
f8994aee MD |
282 | * addition/removal. It automatically keeps track of resize required. |
283 | * We use the bucket length as indicator for need to expand for small | |
ffa11a18 | 284 | * tables and machines lacking per-cpu data support. |
f8994aee MD |
285 | */ |
286 | #define COUNT_COMMIT_ORDER 10 | |
4ddbb355 | 287 | #define DEFAULT_SPLIT_COUNT_MASK 0xFUL |
6ea6bc67 MD |
288 | #define CHAIN_LEN_TARGET 1 |
289 | #define CHAIN_LEN_RESIZE_THRESHOLD 3 | |
2ed95849 | 290 | |
cd95516d | 291 | /* |
76a73da8 | 292 | * Define the minimum table size. |
cd95516d | 293 | */ |
d0d8f9aa LJ |
294 | #define MIN_TABLE_ORDER 0 |
295 | #define MIN_TABLE_SIZE (1UL << MIN_TABLE_ORDER) | |
cd95516d | 296 | |
b7d619b0 | 297 | /* |
1ee8f000 | 298 | * Minimum number of bucket nodes to touch per thread to parallelize grow/shrink. |
b7d619b0 | 299 | */ |
6083a889 MD |
300 | #define MIN_PARTITION_PER_THREAD_ORDER 12 |
301 | #define MIN_PARTITION_PER_THREAD (1UL << MIN_PARTITION_PER_THREAD_ORDER) | |
b7d619b0 | 302 | |
d95bd160 MD |
303 | /* |
304 | * The removed flag needs to be updated atomically with the pointer. | |
48ed1c18 | 305 | * It indicates that no node must attach to the node scheduled for |
b198f0fd | 306 | * removal, and that node garbage collection must be performed. |
1ee8f000 | 307 | * The bucket flag does not require to be updated atomically with the |
d95bd160 | 308 | * pointer, but it is added as a pointer low bit flag to save space. |
1f67ba50 MD |
309 | * The "removal owner" flag is used to detect which of the "del" |
310 | * operation that has set the "removed flag" gets to return the removed | |
311 | * node to its caller. Note that the replace operation does not need to | |
312 | * iteract with the "removal owner" flag, because it validates that | |
313 | * the "removed" flag is not set before performing its cmpxchg. | |
d95bd160 | 314 | */ |
d37166c6 | 315 | #define REMOVED_FLAG (1UL << 0) |
1ee8f000 | 316 | #define BUCKET_FLAG (1UL << 1) |
db00ccc3 MD |
317 | #define REMOVAL_OWNER_FLAG (1UL << 2) |
318 | #define FLAGS_MASK ((1UL << 3) - 1) | |
d37166c6 | 319 | |
bb7b2f26 | 320 | /* Value of the end pointer. Should not interact with flags. */ |
f9c80341 | 321 | #define END_VALUE NULL |
bb7b2f26 | 322 | |
7f52427b MD |
323 | /* |
324 | * ht_items_count: Split-counters counting the number of node addition | |
325 | * and removal in the table. Only used if the CDS_LFHT_ACCOUNTING flag | |
326 | * is set at hash table creation. | |
327 | * | |
328 | * These are free-running counters, never reset to zero. They count the | |
329 | * number of add/remove, and trigger every (1 << COUNT_COMMIT_ORDER) | |
330 | * operations to update the global counter. We choose a power-of-2 value | |
331 | * for the trigger to deal with 32 or 64-bit overflow of the counter. | |
332 | */ | |
df44348d | 333 | struct ht_items_count { |
860d07e8 | 334 | unsigned long add, del; |
df44348d MD |
335 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
336 | ||
7f52427b MD |
337 | /* |
338 | * rcu_resize_work: Contains arguments passed to RCU worker thread | |
339 | * responsible for performing lazy resize. | |
340 | */ | |
abc490a1 MD |
341 | struct rcu_resize_work { |
342 | struct rcu_head head; | |
14044b37 | 343 | struct cds_lfht *ht; |
abc490a1 | 344 | }; |
2ed95849 | 345 | |
7f52427b MD |
346 | /* |
347 | * partition_resize_work: Contains arguments passed to worker threads | |
348 | * executing the hash table resize on partitions of the hash table | |
349 | * assigned to each processor's worker thread. | |
350 | */ | |
b7d619b0 | 351 | struct partition_resize_work { |
1af6e26e | 352 | pthread_t thread_id; |
b7d619b0 MD |
353 | struct cds_lfht *ht; |
354 | unsigned long i, start, len; | |
355 | void (*fct)(struct cds_lfht *ht, unsigned long i, | |
356 | unsigned long start, unsigned long len); | |
357 | }; | |
358 | ||
abc490a1 MD |
359 | /* |
360 | * Algorithm to reverse bits in a word by lookup table, extended to | |
361 | * 64-bit words. | |
f9830efd | 362 | * Source: |
abc490a1 | 363 | * http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable |
f9830efd | 364 | * Originally from Public Domain. |
abc490a1 MD |
365 | */ |
366 | ||
67ecffc0 | 367 | static const uint8_t BitReverseTable256[256] = |
2ed95849 | 368 | { |
abc490a1 MD |
369 | #define R2(n) (n), (n) + 2*64, (n) + 1*64, (n) + 3*64 |
370 | #define R4(n) R2(n), R2((n) + 2*16), R2((n) + 1*16), R2((n) + 3*16) | |
371 | #define R6(n) R4(n), R4((n) + 2*4 ), R4((n) + 1*4 ), R4((n) + 3*4 ) | |
372 | R6(0), R6(2), R6(1), R6(3) | |
373 | }; | |
374 | #undef R2 | |
375 | #undef R4 | |
376 | #undef R6 | |
2ed95849 | 377 | |
abc490a1 MD |
378 | static |
379 | uint8_t bit_reverse_u8(uint8_t v) | |
380 | { | |
381 | return BitReverseTable256[v]; | |
382 | } | |
ab7d5fc6 | 383 | |
95bc7fb9 MD |
384 | #if (CAA_BITS_PER_LONG == 32) |
385 | static | |
abc490a1 MD |
386 | uint32_t bit_reverse_u32(uint32_t v) |
387 | { | |
67ecffc0 MD |
388 | return ((uint32_t) bit_reverse_u8(v) << 24) | |
389 | ((uint32_t) bit_reverse_u8(v >> 8) << 16) | | |
390 | ((uint32_t) bit_reverse_u8(v >> 16) << 8) | | |
abc490a1 | 391 | ((uint32_t) bit_reverse_u8(v >> 24)); |
2ed95849 | 392 | } |
95bc7fb9 MD |
393 | #else |
394 | static | |
abc490a1 | 395 | uint64_t bit_reverse_u64(uint64_t v) |
2ed95849 | 396 | { |
67ecffc0 MD |
397 | return ((uint64_t) bit_reverse_u8(v) << 56) | |
398 | ((uint64_t) bit_reverse_u8(v >> 8) << 48) | | |
abc490a1 MD |
399 | ((uint64_t) bit_reverse_u8(v >> 16) << 40) | |
400 | ((uint64_t) bit_reverse_u8(v >> 24) << 32) | | |
67ecffc0 MD |
401 | ((uint64_t) bit_reverse_u8(v >> 32) << 24) | |
402 | ((uint64_t) bit_reverse_u8(v >> 40) << 16) | | |
abc490a1 MD |
403 | ((uint64_t) bit_reverse_u8(v >> 48) << 8) | |
404 | ((uint64_t) bit_reverse_u8(v >> 56)); | |
405 | } | |
95bc7fb9 | 406 | #endif |
abc490a1 MD |
407 | |
408 | static | |
409 | unsigned long bit_reverse_ulong(unsigned long v) | |
410 | { | |
411 | #if (CAA_BITS_PER_LONG == 32) | |
412 | return bit_reverse_u32(v); | |
413 | #else | |
414 | return bit_reverse_u64(v); | |
415 | #endif | |
416 | } | |
417 | ||
f9830efd | 418 | /* |
24365af7 MD |
419 | * fls: returns the position of the most significant bit. |
420 | * Returns 0 if no bit is set, else returns the position of the most | |
421 | * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit). | |
f9830efd | 422 | */ |
24365af7 MD |
423 | #if defined(__i386) || defined(__x86_64) |
424 | static inline | |
425 | unsigned int fls_u32(uint32_t x) | |
f9830efd | 426 | { |
24365af7 MD |
427 | int r; |
428 | ||
e1789ce2 | 429 | __asm__ ("bsrl %1,%0\n\t" |
24365af7 MD |
430 | "jnz 1f\n\t" |
431 | "movl $-1,%0\n\t" | |
432 | "1:\n\t" | |
433 | : "=r" (r) : "rm" (x)); | |
434 | return r + 1; | |
435 | } | |
436 | #define HAS_FLS_U32 | |
437 | #endif | |
438 | ||
439 | #if defined(__x86_64) | |
440 | static inline | |
441 | unsigned int fls_u64(uint64_t x) | |
442 | { | |
443 | long r; | |
444 | ||
e1789ce2 | 445 | __asm__ ("bsrq %1,%0\n\t" |
24365af7 MD |
446 | "jnz 1f\n\t" |
447 | "movq $-1,%0\n\t" | |
448 | "1:\n\t" | |
449 | : "=r" (r) : "rm" (x)); | |
450 | return r + 1; | |
451 | } | |
452 | #define HAS_FLS_U64 | |
453 | #endif | |
454 | ||
455 | #ifndef HAS_FLS_U64 | |
456 | static __attribute__((unused)) | |
457 | unsigned int fls_u64(uint64_t x) | |
458 | { | |
459 | unsigned int r = 64; | |
460 | ||
461 | if (!x) | |
462 | return 0; | |
463 | ||
464 | if (!(x & 0xFFFFFFFF00000000ULL)) { | |
465 | x <<= 32; | |
466 | r -= 32; | |
467 | } | |
468 | if (!(x & 0xFFFF000000000000ULL)) { | |
469 | x <<= 16; | |
470 | r -= 16; | |
471 | } | |
472 | if (!(x & 0xFF00000000000000ULL)) { | |
473 | x <<= 8; | |
474 | r -= 8; | |
475 | } | |
476 | if (!(x & 0xF000000000000000ULL)) { | |
477 | x <<= 4; | |
478 | r -= 4; | |
479 | } | |
480 | if (!(x & 0xC000000000000000ULL)) { | |
481 | x <<= 2; | |
482 | r -= 2; | |
483 | } | |
484 | if (!(x & 0x8000000000000000ULL)) { | |
485 | x <<= 1; | |
486 | r -= 1; | |
487 | } | |
488 | return r; | |
489 | } | |
490 | #endif | |
491 | ||
492 | #ifndef HAS_FLS_U32 | |
493 | static __attribute__((unused)) | |
494 | unsigned int fls_u32(uint32_t x) | |
495 | { | |
496 | unsigned int r = 32; | |
f9830efd | 497 | |
24365af7 MD |
498 | if (!x) |
499 | return 0; | |
500 | if (!(x & 0xFFFF0000U)) { | |
501 | x <<= 16; | |
502 | r -= 16; | |
503 | } | |
504 | if (!(x & 0xFF000000U)) { | |
505 | x <<= 8; | |
506 | r -= 8; | |
507 | } | |
508 | if (!(x & 0xF0000000U)) { | |
509 | x <<= 4; | |
510 | r -= 4; | |
511 | } | |
512 | if (!(x & 0xC0000000U)) { | |
513 | x <<= 2; | |
514 | r -= 2; | |
515 | } | |
516 | if (!(x & 0x80000000U)) { | |
517 | x <<= 1; | |
518 | r -= 1; | |
519 | } | |
520 | return r; | |
521 | } | |
522 | #endif | |
523 | ||
5bc6b66f | 524 | unsigned int cds_lfht_fls_ulong(unsigned long x) |
f9830efd | 525 | { |
6887cc5e | 526 | #if (CAA_BITS_PER_LONG == 32) |
24365af7 MD |
527 | return fls_u32(x); |
528 | #else | |
529 | return fls_u64(x); | |
530 | #endif | |
531 | } | |
f9830efd | 532 | |
920f8ef6 LJ |
533 | /* |
534 | * Return the minimum order for which x <= (1UL << order). | |
535 | * Return -1 if x is 0. | |
536 | */ | |
5bc6b66f | 537 | int cds_lfht_get_count_order_u32(uint32_t x) |
24365af7 | 538 | { |
920f8ef6 LJ |
539 | if (!x) |
540 | return -1; | |
24365af7 | 541 | |
920f8ef6 | 542 | return fls_u32(x - 1); |
24365af7 MD |
543 | } |
544 | ||
920f8ef6 LJ |
545 | /* |
546 | * Return the minimum order for which x <= (1UL << order). | |
547 | * Return -1 if x is 0. | |
548 | */ | |
5bc6b66f | 549 | int cds_lfht_get_count_order_ulong(unsigned long x) |
24365af7 | 550 | { |
920f8ef6 LJ |
551 | if (!x) |
552 | return -1; | |
24365af7 | 553 | |
5bc6b66f | 554 | return cds_lfht_fls_ulong(x - 1); |
f9830efd MD |
555 | } |
556 | ||
557 | static | |
ab65b890 | 558 | void cds_lfht_resize_lazy_grow(struct cds_lfht *ht, unsigned long size, int growth); |
f9830efd | 559 | |
f8994aee | 560 | static |
4105056a | 561 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, |
f8994aee MD |
562 | unsigned long count); |
563 | ||
df44348d | 564 | static long nr_cpus_mask = -1; |
4c42f1b8 | 565 | static long split_count_mask = -1; |
e53ab1eb | 566 | static int split_count_order = -1; |
4c42f1b8 | 567 | |
4ddbb355 | 568 | #if defined(HAVE_SYSCONF) |
4c42f1b8 LJ |
569 | static void ht_init_nr_cpus_mask(void) |
570 | { | |
571 | long maxcpus; | |
572 | ||
573 | maxcpus = sysconf(_SC_NPROCESSORS_CONF); | |
574 | if (maxcpus <= 0) { | |
575 | nr_cpus_mask = -2; | |
576 | return; | |
577 | } | |
578 | /* | |
579 | * round up number of CPUs to next power of two, so we | |
580 | * can use & for modulo. | |
581 | */ | |
5bc6b66f | 582 | maxcpus = 1UL << cds_lfht_get_count_order_ulong(maxcpus); |
4c42f1b8 LJ |
583 | nr_cpus_mask = maxcpus - 1; |
584 | } | |
4ddbb355 LJ |
585 | #else /* #if defined(HAVE_SYSCONF) */ |
586 | static void ht_init_nr_cpus_mask(void) | |
587 | { | |
588 | nr_cpus_mask = -2; | |
589 | } | |
590 | #endif /* #else #if defined(HAVE_SYSCONF) */ | |
df44348d MD |
591 | |
592 | static | |
5afadd12 | 593 | void alloc_split_items_count(struct cds_lfht *ht) |
df44348d | 594 | { |
4c42f1b8 LJ |
595 | if (nr_cpus_mask == -1) { |
596 | ht_init_nr_cpus_mask(); | |
4ddbb355 LJ |
597 | if (nr_cpus_mask < 0) |
598 | split_count_mask = DEFAULT_SPLIT_COUNT_MASK; | |
599 | else | |
600 | split_count_mask = nr_cpus_mask; | |
e53ab1eb MD |
601 | split_count_order = |
602 | cds_lfht_get_count_order_ulong(split_count_mask + 1); | |
df44348d | 603 | } |
4c42f1b8 | 604 | |
4ddbb355 | 605 | assert(split_count_mask >= 0); |
5afadd12 LJ |
606 | |
607 | if (ht->flags & CDS_LFHT_ACCOUNTING) { | |
95bc7fb9 MD |
608 | ht->split_count = calloc(split_count_mask + 1, |
609 | sizeof(struct ht_items_count)); | |
5afadd12 LJ |
610 | assert(ht->split_count); |
611 | } else { | |
612 | ht->split_count = NULL; | |
613 | } | |
df44348d MD |
614 | } |
615 | ||
616 | static | |
5afadd12 | 617 | void free_split_items_count(struct cds_lfht *ht) |
df44348d | 618 | { |
5afadd12 | 619 | poison_free(ht->split_count); |
df44348d MD |
620 | } |
621 | ||
622 | static | |
14360f1c | 623 | int ht_get_split_count_index(unsigned long hash) |
df44348d MD |
624 | { |
625 | int cpu; | |
626 | ||
4c42f1b8 | 627 | assert(split_count_mask >= 0); |
a47dd11c | 628 | cpu = urcu_sched_getcpu(); |
8ed51e04 | 629 | if (caa_unlikely(cpu < 0)) |
14360f1c | 630 | return hash & split_count_mask; |
df44348d | 631 | else |
4c42f1b8 | 632 | return cpu & split_count_mask; |
df44348d MD |
633 | } |
634 | ||
635 | static | |
14360f1c | 636 | void ht_count_add(struct cds_lfht *ht, unsigned long size, unsigned long hash) |
df44348d | 637 | { |
4c42f1b8 LJ |
638 | unsigned long split_count; |
639 | int index; | |
314558bf | 640 | long count; |
df44348d | 641 | |
8ed51e04 | 642 | if (caa_unlikely(!ht->split_count)) |
3171717f | 643 | return; |
14360f1c | 644 | index = ht_get_split_count_index(hash); |
4c42f1b8 | 645 | split_count = uatomic_add_return(&ht->split_count[index].add, 1); |
314558bf MD |
646 | if (caa_likely(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1))) |
647 | return; | |
648 | /* Only if number of add multiple of 1UL << COUNT_COMMIT_ORDER */ | |
649 | ||
650 | dbg_printf("add split count %lu\n", split_count); | |
651 | count = uatomic_add_return(&ht->count, | |
652 | 1UL << COUNT_COMMIT_ORDER); | |
4c299dcb | 653 | if (caa_likely(count & (count - 1))) |
314558bf MD |
654 | return; |
655 | /* Only if global count is power of 2 */ | |
656 | ||
657 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) < size) | |
658 | return; | |
659 | dbg_printf("add set global %ld\n", count); | |
660 | cds_lfht_resize_lazy_count(ht, size, | |
661 | count >> (CHAIN_LEN_TARGET - 1)); | |
df44348d MD |
662 | } |
663 | ||
664 | static | |
14360f1c | 665 | void ht_count_del(struct cds_lfht *ht, unsigned long size, unsigned long hash) |
df44348d | 666 | { |
4c42f1b8 LJ |
667 | unsigned long split_count; |
668 | int index; | |
314558bf | 669 | long count; |
df44348d | 670 | |
8ed51e04 | 671 | if (caa_unlikely(!ht->split_count)) |
3171717f | 672 | return; |
14360f1c | 673 | index = ht_get_split_count_index(hash); |
4c42f1b8 | 674 | split_count = uatomic_add_return(&ht->split_count[index].del, 1); |
314558bf MD |
675 | if (caa_likely(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1))) |
676 | return; | |
677 | /* Only if number of deletes multiple of 1UL << COUNT_COMMIT_ORDER */ | |
678 | ||
679 | dbg_printf("del split count %lu\n", split_count); | |
680 | count = uatomic_add_return(&ht->count, | |
681 | -(1UL << COUNT_COMMIT_ORDER)); | |
4c299dcb | 682 | if (caa_likely(count & (count - 1))) |
314558bf MD |
683 | return; |
684 | /* Only if global count is power of 2 */ | |
685 | ||
686 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) >= size) | |
687 | return; | |
688 | dbg_printf("del set global %ld\n", count); | |
689 | /* | |
690 | * Don't shrink table if the number of nodes is below a | |
691 | * certain threshold. | |
692 | */ | |
693 | if (count < (1UL << COUNT_COMMIT_ORDER) * (split_count_mask + 1)) | |
694 | return; | |
695 | cds_lfht_resize_lazy_count(ht, size, | |
696 | count >> (CHAIN_LEN_TARGET - 1)); | |
df44348d MD |
697 | } |
698 | ||
f9830efd | 699 | static |
4105056a | 700 | void check_resize(struct cds_lfht *ht, unsigned long size, uint32_t chain_len) |
f9830efd | 701 | { |
f8994aee MD |
702 | unsigned long count; |
703 | ||
b8af5011 MD |
704 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) |
705 | return; | |
f8994aee MD |
706 | count = uatomic_read(&ht->count); |
707 | /* | |
708 | * Use bucket-local length for small table expand and for | |
709 | * environments lacking per-cpu data support. | |
710 | */ | |
e53ab1eb | 711 | if (count >= (1UL << (COUNT_COMMIT_ORDER + split_count_order))) |
f8994aee | 712 | return; |
24365af7 | 713 | if (chain_len > 100) |
f0c29ed7 | 714 | dbg_printf("WARNING: large chain length: %u.\n", |
24365af7 | 715 | chain_len); |
e53ab1eb MD |
716 | if (chain_len >= CHAIN_LEN_RESIZE_THRESHOLD) { |
717 | int growth; | |
718 | ||
719 | /* | |
720 | * Ideal growth calculated based on chain length. | |
721 | */ | |
722 | growth = cds_lfht_get_count_order_u32(chain_len | |
723 | - (CHAIN_LEN_TARGET - 1)); | |
724 | if ((ht->flags & CDS_LFHT_ACCOUNTING) | |
725 | && (size << growth) | |
726 | >= (1UL << (COUNT_COMMIT_ORDER | |
727 | + split_count_order))) { | |
728 | /* | |
729 | * If ideal growth expands the hash table size | |
730 | * beyond the "small hash table" sizes, use the | |
731 | * maximum small hash table size to attempt | |
732 | * expanding the hash table. This only applies | |
733 | * when node accounting is available, otherwise | |
734 | * the chain length is used to expand the hash | |
735 | * table in every case. | |
736 | */ | |
737 | growth = COUNT_COMMIT_ORDER + split_count_order | |
738 | - cds_lfht_get_count_order_ulong(size); | |
739 | if (growth <= 0) | |
740 | return; | |
741 | } | |
742 | cds_lfht_resize_lazy_grow(ht, size, growth); | |
743 | } | |
f9830efd MD |
744 | } |
745 | ||
abc490a1 | 746 | static |
14044b37 | 747 | struct cds_lfht_node *clear_flag(struct cds_lfht_node *node) |
abc490a1 | 748 | { |
14044b37 | 749 | return (struct cds_lfht_node *) (((unsigned long) node) & ~FLAGS_MASK); |
abc490a1 MD |
750 | } |
751 | ||
752 | static | |
14044b37 | 753 | int is_removed(struct cds_lfht_node *node) |
abc490a1 | 754 | { |
d37166c6 | 755 | return ((unsigned long) node) & REMOVED_FLAG; |
abc490a1 MD |
756 | } |
757 | ||
f5596c94 | 758 | static |
1ee8f000 | 759 | int is_bucket(struct cds_lfht_node *node) |
f5596c94 | 760 | { |
1ee8f000 | 761 | return ((unsigned long) node) & BUCKET_FLAG; |
f5596c94 MD |
762 | } |
763 | ||
764 | static | |
1ee8f000 | 765 | struct cds_lfht_node *flag_bucket(struct cds_lfht_node *node) |
f5596c94 | 766 | { |
1ee8f000 | 767 | return (struct cds_lfht_node *) (((unsigned long) node) | BUCKET_FLAG); |
f5596c94 | 768 | } |
bb7b2f26 | 769 | |
db00ccc3 MD |
770 | static |
771 | int is_removal_owner(struct cds_lfht_node *node) | |
772 | { | |
773 | return ((unsigned long) node) & REMOVAL_OWNER_FLAG; | |
774 | } | |
775 | ||
776 | static | |
777 | struct cds_lfht_node *flag_removal_owner(struct cds_lfht_node *node) | |
778 | { | |
779 | return (struct cds_lfht_node *) (((unsigned long) node) | REMOVAL_OWNER_FLAG); | |
780 | } | |
781 | ||
71bb3aca MD |
782 | static |
783 | struct cds_lfht_node *flag_removed_or_removal_owner(struct cds_lfht_node *node) | |
784 | { | |
785 | return (struct cds_lfht_node *) (((unsigned long) node) | REMOVED_FLAG | REMOVAL_OWNER_FLAG); | |
786 | } | |
787 | ||
bb7b2f26 MD |
788 | static |
789 | struct cds_lfht_node *get_end(void) | |
790 | { | |
791 | return (struct cds_lfht_node *) END_VALUE; | |
792 | } | |
793 | ||
794 | static | |
795 | int is_end(struct cds_lfht_node *node) | |
796 | { | |
797 | return clear_flag(node) == (struct cds_lfht_node *) END_VALUE; | |
798 | } | |
799 | ||
abc490a1 | 800 | static |
ab65b890 LJ |
801 | unsigned long _uatomic_xchg_monotonic_increase(unsigned long *ptr, |
802 | unsigned long v) | |
abc490a1 MD |
803 | { |
804 | unsigned long old1, old2; | |
805 | ||
806 | old1 = uatomic_read(ptr); | |
807 | do { | |
808 | old2 = old1; | |
809 | if (old2 >= v) | |
f9830efd | 810 | return old2; |
abc490a1 | 811 | } while ((old1 = uatomic_cmpxchg(ptr, old2, v)) != old2); |
ab65b890 | 812 | return old2; |
abc490a1 MD |
813 | } |
814 | ||
48f1b16d LJ |
815 | static |
816 | void cds_lfht_alloc_bucket_table(struct cds_lfht *ht, unsigned long order) | |
817 | { | |
0b6aa001 | 818 | return ht->mm->alloc_bucket_table(ht, order); |
48f1b16d LJ |
819 | } |
820 | ||
821 | /* | |
822 | * cds_lfht_free_bucket_table() should be called with decreasing order. | |
823 | * When cds_lfht_free_bucket_table(0) is called, it means the whole | |
824 | * lfht is destroyed. | |
825 | */ | |
826 | static | |
827 | void cds_lfht_free_bucket_table(struct cds_lfht *ht, unsigned long order) | |
828 | { | |
0b6aa001 | 829 | return ht->mm->free_bucket_table(ht, order); |
48f1b16d LJ |
830 | } |
831 | ||
9d72a73f LJ |
832 | static inline |
833 | struct cds_lfht_node *bucket_at(struct cds_lfht *ht, unsigned long index) | |
f4a9cc0b | 834 | { |
0b6aa001 | 835 | return ht->bucket_at(ht, index); |
f4a9cc0b LJ |
836 | } |
837 | ||
9d72a73f LJ |
838 | static inline |
839 | struct cds_lfht_node *lookup_bucket(struct cds_lfht *ht, unsigned long size, | |
840 | unsigned long hash) | |
841 | { | |
842 | assert(size > 0); | |
843 | return bucket_at(ht, hash & (size - 1)); | |
844 | } | |
845 | ||
273399de MD |
846 | /* |
847 | * Remove all logically deleted nodes from a bucket up to a certain node key. | |
848 | */ | |
849 | static | |
1ee8f000 | 850 | void _cds_lfht_gc_bucket(struct cds_lfht_node *bucket, struct cds_lfht_node *node) |
273399de | 851 | { |
14044b37 | 852 | struct cds_lfht_node *iter_prev, *iter, *next, *new_next; |
273399de | 853 | |
1ee8f000 LJ |
854 | assert(!is_bucket(bucket)); |
855 | assert(!is_removed(bucket)); | |
2f943cd7 | 856 | assert(!is_removal_owner(bucket)); |
1ee8f000 | 857 | assert(!is_bucket(node)); |
c90201ac | 858 | assert(!is_removed(node)); |
2f943cd7 | 859 | assert(!is_removal_owner(node)); |
273399de | 860 | for (;;) { |
1ee8f000 LJ |
861 | iter_prev = bucket; |
862 | /* We can always skip the bucket node initially */ | |
04db56f8 | 863 | iter = rcu_dereference(iter_prev->next); |
b4cb483f | 864 | assert(!is_removed(iter)); |
2f943cd7 | 865 | assert(!is_removal_owner(iter)); |
04db56f8 | 866 | assert(iter_prev->reverse_hash <= node->reverse_hash); |
bd4db153 | 867 | /* |
1ee8f000 | 868 | * We should never be called with bucket (start of chain) |
bd4db153 MD |
869 | * and logically removed node (end of path compression |
870 | * marker) being the actual same node. This would be a | |
871 | * bug in the algorithm implementation. | |
872 | */ | |
1ee8f000 | 873 | assert(bucket != node); |
273399de | 874 | for (;;) { |
8ed51e04 | 875 | if (caa_unlikely(is_end(iter))) |
f9c80341 | 876 | return; |
04db56f8 | 877 | if (caa_likely(clear_flag(iter)->reverse_hash > node->reverse_hash)) |
f9c80341 | 878 | return; |
04db56f8 | 879 | next = rcu_dereference(clear_flag(iter)->next); |
8ed51e04 | 880 | if (caa_likely(is_removed(next))) |
273399de | 881 | break; |
b453eae1 | 882 | iter_prev = clear_flag(iter); |
273399de MD |
883 | iter = next; |
884 | } | |
b198f0fd | 885 | assert(!is_removed(iter)); |
2f943cd7 | 886 | assert(!is_removal_owner(iter)); |
1ee8f000 LJ |
887 | if (is_bucket(iter)) |
888 | new_next = flag_bucket(clear_flag(next)); | |
f5596c94 MD |
889 | else |
890 | new_next = clear_flag(next); | |
04db56f8 | 891 | (void) uatomic_cmpxchg(&iter_prev->next, iter, new_next); |
273399de MD |
892 | } |
893 | } | |
894 | ||
9357c415 MD |
895 | static |
896 | int _cds_lfht_replace(struct cds_lfht *ht, unsigned long size, | |
897 | struct cds_lfht_node *old_node, | |
3fb86f26 | 898 | struct cds_lfht_node *old_next, |
9357c415 MD |
899 | struct cds_lfht_node *new_node) |
900 | { | |
04db56f8 | 901 | struct cds_lfht_node *bucket, *ret_next; |
9357c415 MD |
902 | |
903 | if (!old_node) /* Return -ENOENT if asked to replace NULL node */ | |
7801dadd | 904 | return -ENOENT; |
9357c415 MD |
905 | |
906 | assert(!is_removed(old_node)); | |
2f943cd7 | 907 | assert(!is_removal_owner(old_node)); |
1ee8f000 | 908 | assert(!is_bucket(old_node)); |
9357c415 | 909 | assert(!is_removed(new_node)); |
2f943cd7 | 910 | assert(!is_removal_owner(new_node)); |
1ee8f000 | 911 | assert(!is_bucket(new_node)); |
9357c415 | 912 | assert(new_node != old_node); |
3fb86f26 | 913 | for (;;) { |
9357c415 | 914 | /* Insert after node to be replaced */ |
9357c415 MD |
915 | if (is_removed(old_next)) { |
916 | /* | |
917 | * Too late, the old node has been removed under us | |
918 | * between lookup and replace. Fail. | |
919 | */ | |
7801dadd | 920 | return -ENOENT; |
9357c415 | 921 | } |
feda2722 LJ |
922 | assert(old_next == clear_flag(old_next)); |
923 | assert(new_node != old_next); | |
71bb3aca MD |
924 | /* |
925 | * REMOVAL_OWNER flag is _NEVER_ set before the REMOVED | |
926 | * flag. It is either set atomically at the same time | |
927 | * (replace) or after (del). | |
928 | */ | |
929 | assert(!is_removal_owner(old_next)); | |
feda2722 | 930 | new_node->next = old_next; |
9357c415 MD |
931 | /* |
932 | * Here is the whole trick for lock-free replace: we add | |
933 | * the replacement node _after_ the node we want to | |
934 | * replace by atomically setting its next pointer at the | |
935 | * same time we set its removal flag. Given that | |
936 | * the lookups/get next use an iterator aware of the | |
937 | * next pointer, they will either skip the old node due | |
938 | * to the removal flag and see the new node, or use | |
939 | * the old node, but will not see the new one. | |
db00ccc3 MD |
940 | * This is a replacement of a node with another node |
941 | * that has the same value: we are therefore not | |
71bb3aca MD |
942 | * removing a value from the hash table. We set both the |
943 | * REMOVED and REMOVAL_OWNER flags atomically so we own | |
944 | * the node after successful cmpxchg. | |
9357c415 | 945 | */ |
04db56f8 | 946 | ret_next = uatomic_cmpxchg(&old_node->next, |
71bb3aca | 947 | old_next, flag_removed_or_removal_owner(new_node)); |
3fb86f26 | 948 | if (ret_next == old_next) |
7801dadd | 949 | break; /* We performed the replacement. */ |
3fb86f26 LJ |
950 | old_next = ret_next; |
951 | } | |
9357c415 | 952 | |
9357c415 MD |
953 | /* |
954 | * Ensure that the old node is not visible to readers anymore: | |
955 | * lookup for the node, and remove it (along with any other | |
956 | * logically removed node) if found. | |
957 | */ | |
04db56f8 LJ |
958 | bucket = lookup_bucket(ht, size, bit_reverse_ulong(old_node->reverse_hash)); |
959 | _cds_lfht_gc_bucket(bucket, new_node); | |
7801dadd | 960 | |
a85eff52 | 961 | assert(is_removed(CMM_LOAD_SHARED(old_node->next))); |
7801dadd | 962 | return 0; |
9357c415 MD |
963 | } |
964 | ||
83beee94 MD |
965 | /* |
966 | * A non-NULL unique_ret pointer uses the "add unique" (or uniquify) add | |
967 | * mode. A NULL unique_ret allows creation of duplicate keys. | |
968 | */ | |
abc490a1 | 969 | static |
83beee94 | 970 | void _cds_lfht_add(struct cds_lfht *ht, |
91a75cc5 | 971 | unsigned long hash, |
0422d92c | 972 | cds_lfht_match_fct match, |
996ff57c | 973 | const void *key, |
83beee94 MD |
974 | unsigned long size, |
975 | struct cds_lfht_node *node, | |
976 | struct cds_lfht_iter *unique_ret, | |
1ee8f000 | 977 | int bucket_flag) |
abc490a1 | 978 | { |
14044b37 | 979 | struct cds_lfht_node *iter_prev, *iter, *next, *new_node, *new_next, |
960c9e4f | 980 | *return_node; |
04db56f8 | 981 | struct cds_lfht_node *bucket; |
abc490a1 | 982 | |
1ee8f000 | 983 | assert(!is_bucket(node)); |
c90201ac | 984 | assert(!is_removed(node)); |
2f943cd7 | 985 | assert(!is_removal_owner(node)); |
91a75cc5 | 986 | bucket = lookup_bucket(ht, size, hash); |
abc490a1 | 987 | for (;;) { |
adc0de68 | 988 | uint32_t chain_len = 0; |
abc490a1 | 989 | |
11519af6 MD |
990 | /* |
991 | * iter_prev points to the non-removed node prior to the | |
992 | * insert location. | |
11519af6 | 993 | */ |
04db56f8 | 994 | iter_prev = bucket; |
1ee8f000 | 995 | /* We can always skip the bucket node initially */ |
04db56f8 LJ |
996 | iter = rcu_dereference(iter_prev->next); |
997 | assert(iter_prev->reverse_hash <= node->reverse_hash); | |
abc490a1 | 998 | for (;;) { |
8ed51e04 | 999 | if (caa_unlikely(is_end(iter))) |
273399de | 1000 | goto insert; |
04db56f8 | 1001 | if (caa_likely(clear_flag(iter)->reverse_hash > node->reverse_hash)) |
273399de | 1002 | goto insert; |
238cc06e | 1003 | |
1ee8f000 LJ |
1004 | /* bucket node is the first node of the identical-hash-value chain */ |
1005 | if (bucket_flag && clear_flag(iter)->reverse_hash == node->reverse_hash) | |
194fdbd1 | 1006 | goto insert; |
238cc06e | 1007 | |
04db56f8 | 1008 | next = rcu_dereference(clear_flag(iter)->next); |
8ed51e04 | 1009 | if (caa_unlikely(is_removed(next))) |
9dba85be | 1010 | goto gc_node; |
238cc06e LJ |
1011 | |
1012 | /* uniquely add */ | |
83beee94 | 1013 | if (unique_ret |
1ee8f000 | 1014 | && !is_bucket(next) |
04db56f8 | 1015 | && clear_flag(iter)->reverse_hash == node->reverse_hash) { |
238cc06e LJ |
1016 | struct cds_lfht_iter d_iter = { .node = node, .next = iter, }; |
1017 | ||
1018 | /* | |
1019 | * uniquely adding inserts the node as the first | |
1020 | * node of the identical-hash-value node chain. | |
1021 | * | |
1022 | * This semantic ensures no duplicated keys | |
1023 | * should ever be observable in the table | |
1f67ba50 MD |
1024 | * (including traversing the table node by |
1025 | * node by forward iterations) | |
238cc06e | 1026 | */ |
04db56f8 | 1027 | cds_lfht_next_duplicate(ht, match, key, &d_iter); |
238cc06e LJ |
1028 | if (!d_iter.node) |
1029 | goto insert; | |
1030 | ||
1031 | *unique_ret = d_iter; | |
83beee94 | 1032 | return; |
48ed1c18 | 1033 | } |
238cc06e | 1034 | |
11519af6 | 1035 | /* Only account for identical reverse hash once */ |
04db56f8 | 1036 | if (iter_prev->reverse_hash != clear_flag(iter)->reverse_hash |
1ee8f000 | 1037 | && !is_bucket(next)) |
4105056a | 1038 | check_resize(ht, size, ++chain_len); |
11519af6 | 1039 | iter_prev = clear_flag(iter); |
273399de | 1040 | iter = next; |
abc490a1 | 1041 | } |
48ed1c18 | 1042 | |
273399de | 1043 | insert: |
7ec59d3b | 1044 | assert(node != clear_flag(iter)); |
11519af6 | 1045 | assert(!is_removed(iter_prev)); |
2f943cd7 | 1046 | assert(!is_removal_owner(iter_prev)); |
c90201ac | 1047 | assert(!is_removed(iter)); |
2f943cd7 | 1048 | assert(!is_removal_owner(iter)); |
f000907d | 1049 | assert(iter_prev != node); |
1ee8f000 | 1050 | if (!bucket_flag) |
04db56f8 | 1051 | node->next = clear_flag(iter); |
f9c80341 | 1052 | else |
1ee8f000 LJ |
1053 | node->next = flag_bucket(clear_flag(iter)); |
1054 | if (is_bucket(iter)) | |
1055 | new_node = flag_bucket(node); | |
f5596c94 MD |
1056 | else |
1057 | new_node = node; | |
04db56f8 | 1058 | if (uatomic_cmpxchg(&iter_prev->next, iter, |
48ed1c18 | 1059 | new_node) != iter) { |
273399de | 1060 | continue; /* retry */ |
48ed1c18 | 1061 | } else { |
83beee94 | 1062 | return_node = node; |
960c9e4f | 1063 | goto end; |
48ed1c18 MD |
1064 | } |
1065 | ||
9dba85be MD |
1066 | gc_node: |
1067 | assert(!is_removed(iter)); | |
2f943cd7 | 1068 | assert(!is_removal_owner(iter)); |
1ee8f000 LJ |
1069 | if (is_bucket(iter)) |
1070 | new_next = flag_bucket(clear_flag(next)); | |
f5596c94 MD |
1071 | else |
1072 | new_next = clear_flag(next); | |
04db56f8 | 1073 | (void) uatomic_cmpxchg(&iter_prev->next, iter, new_next); |
273399de | 1074 | /* retry */ |
464a1ec9 | 1075 | } |
9357c415 | 1076 | end: |
83beee94 MD |
1077 | if (unique_ret) { |
1078 | unique_ret->node = return_node; | |
1079 | /* unique_ret->next left unset, never used. */ | |
1080 | } | |
abc490a1 | 1081 | } |
464a1ec9 | 1082 | |
abc490a1 | 1083 | static |
860d07e8 | 1084 | int _cds_lfht_del(struct cds_lfht *ht, unsigned long size, |
b65ec430 | 1085 | struct cds_lfht_node *node) |
abc490a1 | 1086 | { |
db00ccc3 | 1087 | struct cds_lfht_node *bucket, *next; |
5e28c532 | 1088 | |
9357c415 | 1089 | if (!node) /* Return -ENOENT if asked to delete NULL node */ |
743f9143 | 1090 | return -ENOENT; |
9357c415 | 1091 | |
7ec59d3b | 1092 | /* logically delete the node */ |
1ee8f000 | 1093 | assert(!is_bucket(node)); |
c90201ac | 1094 | assert(!is_removed(node)); |
db00ccc3 | 1095 | assert(!is_removal_owner(node)); |
48ed1c18 | 1096 | |
db00ccc3 MD |
1097 | /* |
1098 | * We are first checking if the node had previously been | |
1099 | * logically removed (this check is not atomic with setting the | |
1100 | * logical removal flag). Return -ENOENT if the node had | |
1101 | * previously been removed. | |
1102 | */ | |
a85eff52 | 1103 | next = CMM_LOAD_SHARED(node->next); /* next is not dereferenced */ |
db00ccc3 MD |
1104 | if (caa_unlikely(is_removed(next))) |
1105 | return -ENOENT; | |
b65ec430 | 1106 | assert(!is_bucket(next)); |
196f4fab MD |
1107 | /* |
1108 | * The del operation semantic guarantees a full memory barrier | |
1109 | * before the uatomic_or atomic commit of the deletion flag. | |
1110 | */ | |
1111 | cmm_smp_mb__before_uatomic_or(); | |
db00ccc3 MD |
1112 | /* |
1113 | * We set the REMOVED_FLAG unconditionally. Note that there may | |
1114 | * be more than one concurrent thread setting this flag. | |
1115 | * Knowing which wins the race will be known after the garbage | |
1116 | * collection phase, stay tuned! | |
1117 | */ | |
1118 | uatomic_or(&node->next, REMOVED_FLAG); | |
7ec59d3b | 1119 | /* We performed the (logical) deletion. */ |
7ec59d3b MD |
1120 | |
1121 | /* | |
1122 | * Ensure that the node is not visible to readers anymore: lookup for | |
273399de MD |
1123 | * the node, and remove it (along with any other logically removed node) |
1124 | * if found. | |
11519af6 | 1125 | */ |
04db56f8 LJ |
1126 | bucket = lookup_bucket(ht, size, bit_reverse_ulong(node->reverse_hash)); |
1127 | _cds_lfht_gc_bucket(bucket, node); | |
743f9143 | 1128 | |
a85eff52 | 1129 | assert(is_removed(CMM_LOAD_SHARED(node->next))); |
db00ccc3 MD |
1130 | /* |
1131 | * Last phase: atomically exchange node->next with a version | |
1132 | * having "REMOVAL_OWNER_FLAG" set. If the returned node->next | |
1133 | * pointer did _not_ have "REMOVAL_OWNER_FLAG" set, we now own | |
1134 | * the node and win the removal race. | |
1135 | * It is interesting to note that all "add" paths are forbidden | |
1136 | * to change the next pointer starting from the point where the | |
1137 | * REMOVED_FLAG is set, so here using a read, followed by a | |
1138 | * xchg() suffice to guarantee that the xchg() will ever only | |
1139 | * set the "REMOVAL_OWNER_FLAG" (or change nothing if the flag | |
1140 | * was already set). | |
1141 | */ | |
1142 | if (!is_removal_owner(uatomic_xchg(&node->next, | |
1143 | flag_removal_owner(node->next)))) | |
1144 | return 0; | |
1145 | else | |
1146 | return -ENOENT; | |
abc490a1 | 1147 | } |
2ed95849 | 1148 | |
b7d619b0 MD |
1149 | static |
1150 | void *partition_resize_thread(void *arg) | |
1151 | { | |
1152 | struct partition_resize_work *work = arg; | |
1153 | ||
7b17c13e | 1154 | work->ht->flavor->register_thread(); |
b7d619b0 | 1155 | work->fct(work->ht, work->i, work->start, work->len); |
7b17c13e | 1156 | work->ht->flavor->unregister_thread(); |
b7d619b0 MD |
1157 | return NULL; |
1158 | } | |
1159 | ||
1160 | static | |
1161 | void partition_resize_helper(struct cds_lfht *ht, unsigned long i, | |
1162 | unsigned long len, | |
1163 | void (*fct)(struct cds_lfht *ht, unsigned long i, | |
1164 | unsigned long start, unsigned long len)) | |
1165 | { | |
e54ec2f5 | 1166 | unsigned long partition_len, start = 0; |
b7d619b0 | 1167 | struct partition_resize_work *work; |
6083a889 MD |
1168 | int thread, ret; |
1169 | unsigned long nr_threads; | |
b7d619b0 | 1170 | |
d7f3ba4c EW |
1171 | assert(nr_cpus_mask != -1); |
1172 | if (nr_cpus_mask < 0 || len < 2 * MIN_PARTITION_PER_THREAD) | |
1173 | goto fallback; | |
1174 | ||
6083a889 MD |
1175 | /* |
1176 | * Note: nr_cpus_mask + 1 is always power of 2. | |
1177 | * We spawn just the number of threads we need to satisfy the minimum | |
1178 | * partition size, up to the number of CPUs in the system. | |
1179 | */ | |
91452a6a MD |
1180 | if (nr_cpus_mask > 0) { |
1181 | nr_threads = min(nr_cpus_mask + 1, | |
1182 | len >> MIN_PARTITION_PER_THREAD_ORDER); | |
1183 | } else { | |
1184 | nr_threads = 1; | |
1185 | } | |
5bc6b66f | 1186 | partition_len = len >> cds_lfht_get_count_order_ulong(nr_threads); |
6083a889 | 1187 | work = calloc(nr_threads, sizeof(*work)); |
7c75d498 EW |
1188 | if (!work) { |
1189 | dbg_printf("error allocating for resize, single-threading\n"); | |
1190 | goto fallback; | |
1191 | } | |
6083a889 MD |
1192 | for (thread = 0; thread < nr_threads; thread++) { |
1193 | work[thread].ht = ht; | |
1194 | work[thread].i = i; | |
1195 | work[thread].len = partition_len; | |
1196 | work[thread].start = thread * partition_len; | |
1197 | work[thread].fct = fct; | |
1af6e26e | 1198 | ret = pthread_create(&(work[thread].thread_id), ht->resize_attr, |
6083a889 | 1199 | partition_resize_thread, &work[thread]); |
e54ec2f5 EW |
1200 | if (ret == EAGAIN) { |
1201 | /* | |
1202 | * Out of resources: wait and join the threads | |
1203 | * we've created, then handle leftovers. | |
1204 | */ | |
1205 | dbg_printf("error spawning for resize, single-threading\n"); | |
1206 | start = work[thread].start; | |
1207 | len -= start; | |
1208 | nr_threads = thread; | |
1209 | break; | |
1210 | } | |
b7d619b0 MD |
1211 | assert(!ret); |
1212 | } | |
6083a889 | 1213 | for (thread = 0; thread < nr_threads; thread++) { |
1af6e26e | 1214 | ret = pthread_join(work[thread].thread_id, NULL); |
b7d619b0 MD |
1215 | assert(!ret); |
1216 | } | |
1217 | free(work); | |
e54ec2f5 EW |
1218 | |
1219 | /* | |
1220 | * A pthread_create failure above will either lead in us having | |
1221 | * no threads to join or starting at a non-zero offset, | |
1222 | * fallback to single thread processing of leftovers. | |
1223 | */ | |
1224 | if (start == 0 && nr_threads > 0) | |
1225 | return; | |
7c75d498 EW |
1226 | fallback: |
1227 | ht->flavor->thread_online(); | |
e54ec2f5 | 1228 | fct(ht, i, start, len); |
7c75d498 | 1229 | ht->flavor->thread_offline(); |
b7d619b0 MD |
1230 | } |
1231 | ||
e8de508e MD |
1232 | /* |
1233 | * Holding RCU read lock to protect _cds_lfht_add against memory | |
1234 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
1235 | * problem). | |
9ee0fc9a | 1236 | * |
b7d619b0 | 1237 | * When we reach a certain length, we can split this population phase over |
9ee0fc9a MD |
1238 | * many worker threads, based on the number of CPUs available in the system. |
1239 | * This should therefore take care of not having the expand lagging behind too | |
1240 | * many concurrent insertion threads by using the scheduler's ability to | |
1ee8f000 | 1241 | * schedule bucket node population fairly with insertions. |
e8de508e | 1242 | */ |
4105056a | 1243 | static |
b7d619b0 MD |
1244 | void init_table_populate_partition(struct cds_lfht *ht, unsigned long i, |
1245 | unsigned long start, unsigned long len) | |
4105056a | 1246 | { |
9d72a73f | 1247 | unsigned long j, size = 1UL << (i - 1); |
4105056a | 1248 | |
d0d8f9aa | 1249 | assert(i > MIN_TABLE_ORDER); |
7b17c13e | 1250 | ht->flavor->read_lock(); |
9d72a73f LJ |
1251 | for (j = size + start; j < size + start + len; j++) { |
1252 | struct cds_lfht_node *new_node = bucket_at(ht, j); | |
1253 | ||
1254 | assert(j >= size && j < (size << 1)); | |
1255 | dbg_printf("init populate: order %lu index %lu hash %lu\n", | |
1256 | i, j, j); | |
1257 | new_node->reverse_hash = bit_reverse_ulong(j); | |
91a75cc5 | 1258 | _cds_lfht_add(ht, j, NULL, NULL, size, new_node, NULL, 1); |
4105056a | 1259 | } |
7b17c13e | 1260 | ht->flavor->read_unlock(); |
b7d619b0 MD |
1261 | } |
1262 | ||
1263 | static | |
1264 | void init_table_populate(struct cds_lfht *ht, unsigned long i, | |
1265 | unsigned long len) | |
1266 | { | |
b7d619b0 | 1267 | partition_resize_helper(ht, i, len, init_table_populate_partition); |
4105056a MD |
1268 | } |
1269 | ||
abc490a1 | 1270 | static |
4105056a | 1271 | void init_table(struct cds_lfht *ht, |
93d46c39 | 1272 | unsigned long first_order, unsigned long last_order) |
24365af7 | 1273 | { |
93d46c39 | 1274 | unsigned long i; |
24365af7 | 1275 | |
93d46c39 LJ |
1276 | dbg_printf("init table: first_order %lu last_order %lu\n", |
1277 | first_order, last_order); | |
d0d8f9aa | 1278 | assert(first_order > MIN_TABLE_ORDER); |
93d46c39 | 1279 | for (i = first_order; i <= last_order; i++) { |
4105056a | 1280 | unsigned long len; |
24365af7 | 1281 | |
4f6e90b7 | 1282 | len = 1UL << (i - 1); |
f0c29ed7 | 1283 | dbg_printf("init order %lu len: %lu\n", i, len); |
4d676753 MD |
1284 | |
1285 | /* Stop expand if the resize target changes under us */ | |
7b3893e4 | 1286 | if (CMM_LOAD_SHARED(ht->resize_target) < (1UL << i)) |
4d676753 MD |
1287 | break; |
1288 | ||
48f1b16d | 1289 | cds_lfht_alloc_bucket_table(ht, i); |
4105056a | 1290 | |
4105056a | 1291 | /* |
1ee8f000 LJ |
1292 | * Set all bucket nodes reverse hash values for a level and |
1293 | * link all bucket nodes into the table. | |
4105056a | 1294 | */ |
dc1da8f6 | 1295 | init_table_populate(ht, i, len); |
4105056a | 1296 | |
f9c80341 MD |
1297 | /* |
1298 | * Update table size. | |
1299 | */ | |
1300 | cmm_smp_wmb(); /* populate data before RCU size */ | |
7b3893e4 | 1301 | CMM_STORE_SHARED(ht->size, 1UL << i); |
f9c80341 | 1302 | |
4f6e90b7 | 1303 | dbg_printf("init new size: %lu\n", 1UL << i); |
4105056a MD |
1304 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
1305 | break; | |
1306 | } | |
1307 | } | |
1308 | ||
e8de508e MD |
1309 | /* |
1310 | * Holding RCU read lock to protect _cds_lfht_remove against memory | |
1311 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
1312 | * problem). | |
1313 | * For a single level, we logically remove and garbage collect each node. | |
1314 | * | |
1315 | * As a design choice, we perform logical removal and garbage collection on a | |
1316 | * node-per-node basis to simplify this algorithm. We also assume keeping good | |
1317 | * cache locality of the operation would overweight possible performance gain | |
1318 | * that could be achieved by batching garbage collection for multiple levels. | |
1319 | * However, this would have to be justified by benchmarks. | |
1320 | * | |
1321 | * Concurrent removal and add operations are helping us perform garbage | |
1322 | * collection of logically removed nodes. We guarantee that all logically | |
1323 | * removed nodes have been garbage-collected (unlinked) before call_rcu is | |
1ee8f000 | 1324 | * invoked to free a hole level of bucket nodes (after a grace period). |
e8de508e | 1325 | * |
1f67ba50 MD |
1326 | * Logical removal and garbage collection can therefore be done in batch |
1327 | * or on a node-per-node basis, as long as the guarantee above holds. | |
9ee0fc9a | 1328 | * |
b7d619b0 MD |
1329 | * When we reach a certain length, we can split this removal over many worker |
1330 | * threads, based on the number of CPUs available in the system. This should | |
1331 | * take care of not letting resize process lag behind too many concurrent | |
9ee0fc9a | 1332 | * updater threads actively inserting into the hash table. |
e8de508e | 1333 | */ |
4105056a | 1334 | static |
b7d619b0 MD |
1335 | void remove_table_partition(struct cds_lfht *ht, unsigned long i, |
1336 | unsigned long start, unsigned long len) | |
4105056a | 1337 | { |
9d72a73f | 1338 | unsigned long j, size = 1UL << (i - 1); |
4105056a | 1339 | |
d0d8f9aa | 1340 | assert(i > MIN_TABLE_ORDER); |
7b17c13e | 1341 | ht->flavor->read_lock(); |
9d72a73f | 1342 | for (j = size + start; j < size + start + len; j++) { |
2e2ce1e9 LJ |
1343 | struct cds_lfht_node *fini_bucket = bucket_at(ht, j); |
1344 | struct cds_lfht_node *parent_bucket = bucket_at(ht, j - size); | |
9d72a73f LJ |
1345 | |
1346 | assert(j >= size && j < (size << 1)); | |
1347 | dbg_printf("remove entry: order %lu index %lu hash %lu\n", | |
1348 | i, j, j); | |
2e2ce1e9 LJ |
1349 | /* Set the REMOVED_FLAG to freeze the ->next for gc */ |
1350 | uatomic_or(&fini_bucket->next, REMOVED_FLAG); | |
1351 | _cds_lfht_gc_bucket(parent_bucket, fini_bucket); | |
abc490a1 | 1352 | } |
7b17c13e | 1353 | ht->flavor->read_unlock(); |
b7d619b0 MD |
1354 | } |
1355 | ||
1356 | static | |
1357 | void remove_table(struct cds_lfht *ht, unsigned long i, unsigned long len) | |
1358 | { | |
b7d619b0 | 1359 | partition_resize_helper(ht, i, len, remove_table_partition); |
2ed95849 MD |
1360 | } |
1361 | ||
61adb337 MD |
1362 | /* |
1363 | * fini_table() is never called for first_order == 0, which is why | |
1364 | * free_by_rcu_order == 0 can be used as criterion to know if free must | |
1365 | * be called. | |
1366 | */ | |
1475579c | 1367 | static |
4105056a | 1368 | void fini_table(struct cds_lfht *ht, |
93d46c39 | 1369 | unsigned long first_order, unsigned long last_order) |
1475579c | 1370 | { |
93d46c39 | 1371 | long i; |
48f1b16d | 1372 | unsigned long free_by_rcu_order = 0; |
1475579c | 1373 | |
93d46c39 LJ |
1374 | dbg_printf("fini table: first_order %lu last_order %lu\n", |
1375 | first_order, last_order); | |
d0d8f9aa | 1376 | assert(first_order > MIN_TABLE_ORDER); |
93d46c39 | 1377 | for (i = last_order; i >= first_order; i--) { |
4105056a | 1378 | unsigned long len; |
1475579c | 1379 | |
4f6e90b7 | 1380 | len = 1UL << (i - 1); |
e15df1cc | 1381 | dbg_printf("fini order %ld len: %lu\n", i, len); |
4105056a | 1382 | |
4d676753 | 1383 | /* Stop shrink if the resize target changes under us */ |
7b3893e4 | 1384 | if (CMM_LOAD_SHARED(ht->resize_target) > (1UL << (i - 1))) |
4d676753 MD |
1385 | break; |
1386 | ||
1387 | cmm_smp_wmb(); /* populate data before RCU size */ | |
7b3893e4 | 1388 | CMM_STORE_SHARED(ht->size, 1UL << (i - 1)); |
4d676753 MD |
1389 | |
1390 | /* | |
1391 | * We need to wait for all add operations to reach Q.S. (and | |
1392 | * thus use the new table for lookups) before we can start | |
1ee8f000 | 1393 | * releasing the old bucket nodes. Otherwise their lookup will |
4d676753 MD |
1394 | * return a logically removed node as insert position. |
1395 | */ | |
7b17c13e | 1396 | ht->flavor->update_synchronize_rcu(); |
48f1b16d LJ |
1397 | if (free_by_rcu_order) |
1398 | cds_lfht_free_bucket_table(ht, free_by_rcu_order); | |
4d676753 | 1399 | |
21263e21 | 1400 | /* |
1ee8f000 LJ |
1401 | * Set "removed" flag in bucket nodes about to be removed. |
1402 | * Unlink all now-logically-removed bucket node pointers. | |
4105056a MD |
1403 | * Concurrent add/remove operation are helping us doing |
1404 | * the gc. | |
21263e21 | 1405 | */ |
4105056a MD |
1406 | remove_table(ht, i, len); |
1407 | ||
48f1b16d | 1408 | free_by_rcu_order = i; |
4105056a MD |
1409 | |
1410 | dbg_printf("fini new size: %lu\n", 1UL << i); | |
1475579c MD |
1411 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
1412 | break; | |
1413 | } | |
0d14ceb2 | 1414 | |
48f1b16d | 1415 | if (free_by_rcu_order) { |
7b17c13e | 1416 | ht->flavor->update_synchronize_rcu(); |
48f1b16d | 1417 | cds_lfht_free_bucket_table(ht, free_by_rcu_order); |
0d14ceb2 | 1418 | } |
1475579c MD |
1419 | } |
1420 | ||
ff0d69de | 1421 | static |
1ee8f000 | 1422 | void cds_lfht_create_bucket(struct cds_lfht *ht, unsigned long size) |
ff0d69de | 1423 | { |
04db56f8 | 1424 | struct cds_lfht_node *prev, *node; |
9d72a73f | 1425 | unsigned long order, len, i; |
ff0d69de | 1426 | |
48f1b16d | 1427 | cds_lfht_alloc_bucket_table(ht, 0); |
ff0d69de | 1428 | |
9d72a73f LJ |
1429 | dbg_printf("create bucket: order 0 index 0 hash 0\n"); |
1430 | node = bucket_at(ht, 0); | |
1431 | node->next = flag_bucket(get_end()); | |
1432 | node->reverse_hash = 0; | |
ff0d69de | 1433 | |
5bc6b66f | 1434 | for (order = 1; order < cds_lfht_get_count_order_ulong(size) + 1; order++) { |
ff0d69de | 1435 | len = 1UL << (order - 1); |
48f1b16d | 1436 | cds_lfht_alloc_bucket_table(ht, order); |
ff0d69de | 1437 | |
9d72a73f LJ |
1438 | for (i = 0; i < len; i++) { |
1439 | /* | |
1440 | * Now, we are trying to init the node with the | |
1441 | * hash=(len+i) (which is also a bucket with the | |
1442 | * index=(len+i)) and insert it into the hash table, | |
1443 | * so this node has to be inserted after the bucket | |
1444 | * with the index=(len+i)&(len-1)=i. And because there | |
1445 | * is no other non-bucket node nor bucket node with | |
1446 | * larger index/hash inserted, so the bucket node | |
1447 | * being inserted should be inserted directly linked | |
1448 | * after the bucket node with index=i. | |
1449 | */ | |
1450 | prev = bucket_at(ht, i); | |
1451 | node = bucket_at(ht, len + i); | |
ff0d69de | 1452 | |
1ee8f000 | 1453 | dbg_printf("create bucket: order %lu index %lu hash %lu\n", |
9d72a73f LJ |
1454 | order, len + i, len + i); |
1455 | node->reverse_hash = bit_reverse_ulong(len + i); | |
1456 | ||
1457 | /* insert after prev */ | |
1458 | assert(is_bucket(prev->next)); | |
ff0d69de | 1459 | node->next = prev->next; |
1ee8f000 | 1460 | prev->next = flag_bucket(node); |
ff0d69de LJ |
1461 | } |
1462 | } | |
1463 | } | |
1464 | ||
0422d92c | 1465 | struct cds_lfht *_cds_lfht_new(unsigned long init_size, |
0722081a | 1466 | unsigned long min_nr_alloc_buckets, |
747d725c | 1467 | unsigned long max_nr_buckets, |
b8af5011 | 1468 | int flags, |
0b6aa001 | 1469 | const struct cds_lfht_mm_type *mm, |
7b17c13e | 1470 | const struct rcu_flavor_struct *flavor, |
b7d619b0 | 1471 | pthread_attr_t *attr) |
abc490a1 | 1472 | { |
14044b37 | 1473 | struct cds_lfht *ht; |
24365af7 | 1474 | unsigned long order; |
abc490a1 | 1475 | |
0722081a LJ |
1476 | /* min_nr_alloc_buckets must be power of two */ |
1477 | if (!min_nr_alloc_buckets || (min_nr_alloc_buckets & (min_nr_alloc_buckets - 1))) | |
5488222b | 1478 | return NULL; |
747d725c | 1479 | |
8129be4e | 1480 | /* init_size must be power of two */ |
5488222b | 1481 | if (!init_size || (init_size & (init_size - 1))) |
8129be4e | 1482 | return NULL; |
747d725c | 1483 | |
c1888f3a MD |
1484 | /* |
1485 | * Memory management plugin default. | |
1486 | */ | |
1487 | if (!mm) { | |
5a2141a7 MD |
1488 | if (CAA_BITS_PER_LONG > 32 |
1489 | && max_nr_buckets | |
c1888f3a MD |
1490 | && max_nr_buckets <= (1ULL << 32)) { |
1491 | /* | |
1492 | * For 64-bit architectures, with max number of | |
1493 | * buckets small enough not to use the entire | |
1494 | * 64-bit memory mapping space (and allowing a | |
1495 | * fair number of hash table instances), use the | |
1496 | * mmap allocator, which is faster than the | |
1497 | * order allocator. | |
1498 | */ | |
1499 | mm = &cds_lfht_mm_mmap; | |
1500 | } else { | |
1501 | /* | |
1502 | * The fallback is to use the order allocator. | |
1503 | */ | |
1504 | mm = &cds_lfht_mm_order; | |
1505 | } | |
1506 | } | |
1507 | ||
0b6aa001 LJ |
1508 | /* max_nr_buckets == 0 for order based mm means infinite */ |
1509 | if (mm == &cds_lfht_mm_order && !max_nr_buckets) | |
747d725c LJ |
1510 | max_nr_buckets = 1UL << (MAX_TABLE_ORDER - 1); |
1511 | ||
1512 | /* max_nr_buckets must be power of two */ | |
1513 | if (!max_nr_buckets || (max_nr_buckets & (max_nr_buckets - 1))) | |
1514 | return NULL; | |
1515 | ||
0722081a | 1516 | min_nr_alloc_buckets = max(min_nr_alloc_buckets, MIN_TABLE_SIZE); |
d0d8f9aa | 1517 | init_size = max(init_size, MIN_TABLE_SIZE); |
747d725c LJ |
1518 | max_nr_buckets = max(max_nr_buckets, min_nr_alloc_buckets); |
1519 | init_size = min(init_size, max_nr_buckets); | |
0b6aa001 LJ |
1520 | |
1521 | ht = mm->alloc_cds_lfht(min_nr_alloc_buckets, max_nr_buckets); | |
b7d619b0 | 1522 | assert(ht); |
0b6aa001 LJ |
1523 | assert(ht->mm == mm); |
1524 | assert(ht->bucket_at == mm->bucket_at); | |
1525 | ||
b5d6b20f | 1526 | ht->flags = flags; |
7b17c13e | 1527 | ht->flavor = flavor; |
b7d619b0 | 1528 | ht->resize_attr = attr; |
5afadd12 | 1529 | alloc_split_items_count(ht); |
abc490a1 MD |
1530 | /* this mutex should not nest in read-side C.S. */ |
1531 | pthread_mutex_init(&ht->resize_mutex, NULL); | |
5bc6b66f | 1532 | order = cds_lfht_get_count_order_ulong(init_size); |
7b3893e4 | 1533 | ht->resize_target = 1UL << order; |
1ee8f000 | 1534 | cds_lfht_create_bucket(ht, 1UL << order); |
7b3893e4 | 1535 | ht->size = 1UL << order; |
abc490a1 MD |
1536 | return ht; |
1537 | } | |
1538 | ||
6f554439 | 1539 | void cds_lfht_lookup(struct cds_lfht *ht, unsigned long hash, |
996ff57c | 1540 | cds_lfht_match_fct match, const void *key, |
6f554439 | 1541 | struct cds_lfht_iter *iter) |
2ed95849 | 1542 | { |
04db56f8 | 1543 | struct cds_lfht_node *node, *next, *bucket; |
0422d92c | 1544 | unsigned long reverse_hash, size; |
2ed95849 | 1545 | |
abc490a1 | 1546 | reverse_hash = bit_reverse_ulong(hash); |
464a1ec9 | 1547 | |
7b3893e4 | 1548 | size = rcu_dereference(ht->size); |
04db56f8 | 1549 | bucket = lookup_bucket(ht, size, hash); |
1ee8f000 | 1550 | /* We can always skip the bucket node initially */ |
04db56f8 | 1551 | node = rcu_dereference(bucket->next); |
bb7b2f26 | 1552 | node = clear_flag(node); |
2ed95849 | 1553 | for (;;) { |
8ed51e04 | 1554 | if (caa_unlikely(is_end(node))) { |
96ad1112 | 1555 | node = next = NULL; |
abc490a1 | 1556 | break; |
bb7b2f26 | 1557 | } |
04db56f8 | 1558 | if (caa_unlikely(node->reverse_hash > reverse_hash)) { |
96ad1112 | 1559 | node = next = NULL; |
abc490a1 | 1560 | break; |
2ed95849 | 1561 | } |
04db56f8 | 1562 | next = rcu_dereference(node->next); |
7f52427b | 1563 | assert(node == clear_flag(node)); |
8ed51e04 | 1564 | if (caa_likely(!is_removed(next)) |
1ee8f000 | 1565 | && !is_bucket(next) |
04db56f8 | 1566 | && node->reverse_hash == reverse_hash |
0422d92c | 1567 | && caa_likely(match(node, key))) { |
273399de | 1568 | break; |
2ed95849 | 1569 | } |
1b81fe1a | 1570 | node = clear_flag(next); |
2ed95849 | 1571 | } |
a85eff52 | 1572 | assert(!node || !is_bucket(CMM_LOAD_SHARED(node->next))); |
adc0de68 MD |
1573 | iter->node = node; |
1574 | iter->next = next; | |
abc490a1 | 1575 | } |
e0ba718a | 1576 | |
0422d92c | 1577 | void cds_lfht_next_duplicate(struct cds_lfht *ht, cds_lfht_match_fct match, |
996ff57c | 1578 | const void *key, struct cds_lfht_iter *iter) |
a481e5ff | 1579 | { |
adc0de68 | 1580 | struct cds_lfht_node *node, *next; |
a481e5ff | 1581 | unsigned long reverse_hash; |
a481e5ff | 1582 | |
adc0de68 | 1583 | node = iter->node; |
04db56f8 | 1584 | reverse_hash = node->reverse_hash; |
adc0de68 | 1585 | next = iter->next; |
a481e5ff MD |
1586 | node = clear_flag(next); |
1587 | ||
1588 | for (;;) { | |
8ed51e04 | 1589 | if (caa_unlikely(is_end(node))) { |
96ad1112 | 1590 | node = next = NULL; |
a481e5ff | 1591 | break; |
bb7b2f26 | 1592 | } |
04db56f8 | 1593 | if (caa_unlikely(node->reverse_hash > reverse_hash)) { |
96ad1112 | 1594 | node = next = NULL; |
a481e5ff MD |
1595 | break; |
1596 | } | |
04db56f8 | 1597 | next = rcu_dereference(node->next); |
8ed51e04 | 1598 | if (caa_likely(!is_removed(next)) |
1ee8f000 | 1599 | && !is_bucket(next) |
04db56f8 | 1600 | && caa_likely(match(node, key))) { |
a481e5ff MD |
1601 | break; |
1602 | } | |
1603 | node = clear_flag(next); | |
1604 | } | |
a85eff52 | 1605 | assert(!node || !is_bucket(CMM_LOAD_SHARED(node->next))); |
adc0de68 MD |
1606 | iter->node = node; |
1607 | iter->next = next; | |
a481e5ff MD |
1608 | } |
1609 | ||
4e9b9fbf MD |
1610 | void cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_iter *iter) |
1611 | { | |
1612 | struct cds_lfht_node *node, *next; | |
1613 | ||
853395e1 | 1614 | node = clear_flag(iter->next); |
4e9b9fbf | 1615 | for (;;) { |
8ed51e04 | 1616 | if (caa_unlikely(is_end(node))) { |
4e9b9fbf MD |
1617 | node = next = NULL; |
1618 | break; | |
1619 | } | |
04db56f8 | 1620 | next = rcu_dereference(node->next); |
8ed51e04 | 1621 | if (caa_likely(!is_removed(next)) |
1ee8f000 | 1622 | && !is_bucket(next)) { |
4e9b9fbf MD |
1623 | break; |
1624 | } | |
1625 | node = clear_flag(next); | |
1626 | } | |
a85eff52 | 1627 | assert(!node || !is_bucket(CMM_LOAD_SHARED(node->next))); |
4e9b9fbf MD |
1628 | iter->node = node; |
1629 | iter->next = next; | |
1630 | } | |
1631 | ||
1632 | void cds_lfht_first(struct cds_lfht *ht, struct cds_lfht_iter *iter) | |
1633 | { | |
4e9b9fbf | 1634 | /* |
1ee8f000 | 1635 | * Get next after first bucket node. The first bucket node is the |
4e9b9fbf MD |
1636 | * first node of the linked list. |
1637 | */ | |
9d72a73f | 1638 | iter->next = bucket_at(ht, 0)->next; |
4e9b9fbf MD |
1639 | cds_lfht_next(ht, iter); |
1640 | } | |
1641 | ||
0422d92c MD |
1642 | void cds_lfht_add(struct cds_lfht *ht, unsigned long hash, |
1643 | struct cds_lfht_node *node) | |
abc490a1 | 1644 | { |
0422d92c | 1645 | unsigned long size; |
ab7d5fc6 | 1646 | |
709bacf9 | 1647 | node->reverse_hash = bit_reverse_ulong(hash); |
7b3893e4 | 1648 | size = rcu_dereference(ht->size); |
91a75cc5 | 1649 | _cds_lfht_add(ht, hash, NULL, NULL, size, node, NULL, 0); |
14360f1c | 1650 | ht_count_add(ht, size, hash); |
3eca1b8c MD |
1651 | } |
1652 | ||
14044b37 | 1653 | struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, |
6f554439 | 1654 | unsigned long hash, |
0422d92c | 1655 | cds_lfht_match_fct match, |
996ff57c | 1656 | const void *key, |
48ed1c18 | 1657 | struct cds_lfht_node *node) |
3eca1b8c | 1658 | { |
0422d92c | 1659 | unsigned long size; |
83beee94 | 1660 | struct cds_lfht_iter iter; |
3eca1b8c | 1661 | |
709bacf9 | 1662 | node->reverse_hash = bit_reverse_ulong(hash); |
7b3893e4 | 1663 | size = rcu_dereference(ht->size); |
91a75cc5 | 1664 | _cds_lfht_add(ht, hash, match, key, size, node, &iter, 0); |
83beee94 | 1665 | if (iter.node == node) |
14360f1c | 1666 | ht_count_add(ht, size, hash); |
83beee94 | 1667 | return iter.node; |
2ed95849 MD |
1668 | } |
1669 | ||
9357c415 | 1670 | struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht, |
6f554439 | 1671 | unsigned long hash, |
0422d92c | 1672 | cds_lfht_match_fct match, |
996ff57c | 1673 | const void *key, |
48ed1c18 MD |
1674 | struct cds_lfht_node *node) |
1675 | { | |
0422d92c | 1676 | unsigned long size; |
83beee94 | 1677 | struct cds_lfht_iter iter; |
48ed1c18 | 1678 | |
709bacf9 | 1679 | node->reverse_hash = bit_reverse_ulong(hash); |
7b3893e4 | 1680 | size = rcu_dereference(ht->size); |
83beee94 | 1681 | for (;;) { |
91a75cc5 | 1682 | _cds_lfht_add(ht, hash, match, key, size, node, &iter, 0); |
83beee94 | 1683 | if (iter.node == node) { |
14360f1c | 1684 | ht_count_add(ht, size, hash); |
83beee94 MD |
1685 | return NULL; |
1686 | } | |
1687 | ||
1688 | if (!_cds_lfht_replace(ht, size, iter.node, iter.next, node)) | |
1689 | return iter.node; | |
1690 | } | |
48ed1c18 MD |
1691 | } |
1692 | ||
2e79c445 MD |
1693 | int cds_lfht_replace(struct cds_lfht *ht, |
1694 | struct cds_lfht_iter *old_iter, | |
1695 | unsigned long hash, | |
1696 | cds_lfht_match_fct match, | |
1697 | const void *key, | |
9357c415 MD |
1698 | struct cds_lfht_node *new_node) |
1699 | { | |
1700 | unsigned long size; | |
1701 | ||
709bacf9 | 1702 | new_node->reverse_hash = bit_reverse_ulong(hash); |
2e79c445 MD |
1703 | if (!old_iter->node) |
1704 | return -ENOENT; | |
1705 | if (caa_unlikely(old_iter->node->reverse_hash != new_node->reverse_hash)) | |
1706 | return -EINVAL; | |
1707 | if (caa_unlikely(!match(old_iter->node, key))) | |
1708 | return -EINVAL; | |
7b3893e4 | 1709 | size = rcu_dereference(ht->size); |
9357c415 MD |
1710 | return _cds_lfht_replace(ht, size, old_iter->node, old_iter->next, |
1711 | new_node); | |
1712 | } | |
1713 | ||
bc8c3c74 | 1714 | int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_node *node) |
2ed95849 | 1715 | { |
95bc7fb9 | 1716 | unsigned long size; |
df44348d | 1717 | int ret; |
abc490a1 | 1718 | |
7b3893e4 | 1719 | size = rcu_dereference(ht->size); |
bc8c3c74 | 1720 | ret = _cds_lfht_del(ht, size, node); |
14360f1c | 1721 | if (!ret) { |
95bc7fb9 MD |
1722 | unsigned long hash; |
1723 | ||
bc8c3c74 | 1724 | hash = bit_reverse_ulong(node->reverse_hash); |
14360f1c LJ |
1725 | ht_count_del(ht, size, hash); |
1726 | } | |
df44348d | 1727 | return ret; |
2ed95849 | 1728 | } |
ab7d5fc6 | 1729 | |
df55172a MD |
1730 | int cds_lfht_is_node_deleted(struct cds_lfht_node *node) |
1731 | { | |
a85eff52 | 1732 | return is_removed(CMM_LOAD_SHARED(node->next)); |
df55172a MD |
1733 | } |
1734 | ||
abc490a1 | 1735 | static |
1ee8f000 | 1736 | int cds_lfht_delete_bucket(struct cds_lfht *ht) |
674f7a69 | 1737 | { |
14044b37 | 1738 | struct cds_lfht_node *node; |
4105056a | 1739 | unsigned long order, i, size; |
674f7a69 | 1740 | |
abc490a1 | 1741 | /* Check that the table is empty */ |
9d72a73f | 1742 | node = bucket_at(ht, 0); |
abc490a1 | 1743 | do { |
04db56f8 | 1744 | node = clear_flag(node)->next; |
1ee8f000 | 1745 | if (!is_bucket(node)) |
abc490a1 | 1746 | return -EPERM; |
273399de | 1747 | assert(!is_removed(node)); |
2f943cd7 | 1748 | assert(!is_removal_owner(node)); |
bb7b2f26 | 1749 | } while (!is_end(node)); |
4105056a MD |
1750 | /* |
1751 | * size accessed without rcu_dereference because hash table is | |
1752 | * being destroyed. | |
1753 | */ | |
7b3893e4 | 1754 | size = ht->size; |
1f67ba50 | 1755 | /* Internal sanity check: all nodes left should be buckets */ |
48f1b16d LJ |
1756 | for (i = 0; i < size; i++) { |
1757 | node = bucket_at(ht, i); | |
1758 | dbg_printf("delete bucket: index %lu expected hash %lu hash %lu\n", | |
1759 | i, i, bit_reverse_ulong(node->reverse_hash)); | |
1760 | assert(is_bucket(node->next)); | |
1761 | } | |
24365af7 | 1762 | |
5bc6b66f | 1763 | for (order = cds_lfht_get_count_order_ulong(size); (long)order >= 0; order--) |
48f1b16d | 1764 | cds_lfht_free_bucket_table(ht, order); |
5488222b | 1765 | |
abc490a1 | 1766 | return 0; |
674f7a69 MD |
1767 | } |
1768 | ||
1769 | /* | |
1770 | * Should only be called when no more concurrent readers nor writers can | |
1771 | * possibly access the table. | |
1772 | */ | |
b7d619b0 | 1773 | int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr) |
674f7a69 | 1774 | { |
a1e5e232 | 1775 | int ret, was_online; |
5e28c532 | 1776 | |
848d4088 | 1777 | /* Wait for in-flight resize operations to complete */ |
24953e08 MD |
1778 | _CMM_STORE_SHARED(ht->in_progress_destroy, 1); |
1779 | cmm_smp_mb(); /* Store destroy before load resize */ | |
a1e5e232 MD |
1780 | was_online = ht->flavor->read_ongoing(); |
1781 | if (was_online) | |
1782 | ht->flavor->thread_offline(); | |
10e68472 MD |
1783 | /* Calling with RCU read-side held is an error. */ |
1784 | if (ht->flavor->read_ongoing()) { | |
1785 | ret = -EINVAL; | |
1786 | if (was_online) | |
1787 | ht->flavor->thread_online(); | |
1788 | goto end; | |
1789 | } | |
848d4088 MD |
1790 | while (uatomic_read(&ht->in_progress_resize)) |
1791 | poll(NULL, 0, 100); /* wait for 100ms */ | |
a1e5e232 MD |
1792 | if (was_online) |
1793 | ht->flavor->thread_online(); | |
1ee8f000 | 1794 | ret = cds_lfht_delete_bucket(ht); |
abc490a1 MD |
1795 | if (ret) |
1796 | return ret; | |
5afadd12 | 1797 | free_split_items_count(ht); |
b7d619b0 MD |
1798 | if (attr) |
1799 | *attr = ht->resize_attr; | |
59629f09 MD |
1800 | ret = pthread_mutex_destroy(&ht->resize_mutex); |
1801 | if (ret) | |
1802 | ret = -EBUSY; | |
98808fb1 | 1803 | poison_free(ht); |
10e68472 | 1804 | end: |
5e28c532 | 1805 | return ret; |
674f7a69 MD |
1806 | } |
1807 | ||
14044b37 | 1808 | void cds_lfht_count_nodes(struct cds_lfht *ht, |
d933dd0e | 1809 | long *approx_before, |
273399de | 1810 | unsigned long *count, |
d933dd0e | 1811 | long *approx_after) |
273399de | 1812 | { |
14044b37 | 1813 | struct cds_lfht_node *node, *next; |
caf3653d | 1814 | unsigned long nr_bucket = 0, nr_removed = 0; |
273399de | 1815 | |
7ed7682f | 1816 | *approx_before = 0; |
5afadd12 | 1817 | if (ht->split_count) { |
973e5e1b MD |
1818 | int i; |
1819 | ||
4c42f1b8 LJ |
1820 | for (i = 0; i < split_count_mask + 1; i++) { |
1821 | *approx_before += uatomic_read(&ht->split_count[i].add); | |
1822 | *approx_before -= uatomic_read(&ht->split_count[i].del); | |
973e5e1b MD |
1823 | } |
1824 | } | |
1825 | ||
273399de | 1826 | *count = 0; |
273399de | 1827 | |
1ee8f000 | 1828 | /* Count non-bucket nodes in the table */ |
9d72a73f | 1829 | node = bucket_at(ht, 0); |
273399de | 1830 | do { |
04db56f8 | 1831 | next = rcu_dereference(node->next); |
b198f0fd | 1832 | if (is_removed(next)) { |
1ee8f000 | 1833 | if (!is_bucket(next)) |
caf3653d | 1834 | (nr_removed)++; |
973e5e1b | 1835 | else |
1ee8f000 LJ |
1836 | (nr_bucket)++; |
1837 | } else if (!is_bucket(next)) | |
273399de | 1838 | (*count)++; |
24365af7 | 1839 | else |
1ee8f000 | 1840 | (nr_bucket)++; |
273399de | 1841 | node = clear_flag(next); |
bb7b2f26 | 1842 | } while (!is_end(node)); |
caf3653d | 1843 | dbg_printf("number of logically removed nodes: %lu\n", nr_removed); |
1ee8f000 | 1844 | dbg_printf("number of bucket nodes: %lu\n", nr_bucket); |
7ed7682f | 1845 | *approx_after = 0; |
5afadd12 | 1846 | if (ht->split_count) { |
973e5e1b MD |
1847 | int i; |
1848 | ||
4c42f1b8 LJ |
1849 | for (i = 0; i < split_count_mask + 1; i++) { |
1850 | *approx_after += uatomic_read(&ht->split_count[i].add); | |
1851 | *approx_after -= uatomic_read(&ht->split_count[i].del); | |
973e5e1b MD |
1852 | } |
1853 | } | |
273399de MD |
1854 | } |
1855 | ||
1475579c | 1856 | /* called with resize mutex held */ |
abc490a1 | 1857 | static |
4105056a | 1858 | void _do_cds_lfht_grow(struct cds_lfht *ht, |
1475579c | 1859 | unsigned long old_size, unsigned long new_size) |
abc490a1 | 1860 | { |
1475579c | 1861 | unsigned long old_order, new_order; |
1475579c | 1862 | |
5bc6b66f MD |
1863 | old_order = cds_lfht_get_count_order_ulong(old_size); |
1864 | new_order = cds_lfht_get_count_order_ulong(new_size); | |
1a401918 LJ |
1865 | dbg_printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", |
1866 | old_size, old_order, new_size, new_order); | |
1475579c | 1867 | assert(new_size > old_size); |
93d46c39 | 1868 | init_table(ht, old_order + 1, new_order); |
abc490a1 MD |
1869 | } |
1870 | ||
1871 | /* called with resize mutex held */ | |
1872 | static | |
4105056a | 1873 | void _do_cds_lfht_shrink(struct cds_lfht *ht, |
1475579c | 1874 | unsigned long old_size, unsigned long new_size) |
464a1ec9 | 1875 | { |
1475579c | 1876 | unsigned long old_order, new_order; |
464a1ec9 | 1877 | |
d0d8f9aa | 1878 | new_size = max(new_size, MIN_TABLE_SIZE); |
5bc6b66f MD |
1879 | old_order = cds_lfht_get_count_order_ulong(old_size); |
1880 | new_order = cds_lfht_get_count_order_ulong(new_size); | |
1a401918 LJ |
1881 | dbg_printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", |
1882 | old_size, old_order, new_size, new_order); | |
1475579c | 1883 | assert(new_size < old_size); |
1475579c | 1884 | |
1ee8f000 | 1885 | /* Remove and unlink all bucket nodes to remove. */ |
93d46c39 | 1886 | fini_table(ht, new_order + 1, old_order); |
464a1ec9 MD |
1887 | } |
1888 | ||
1475579c MD |
1889 | |
1890 | /* called with resize mutex held */ | |
1891 | static | |
1892 | void _do_cds_lfht_resize(struct cds_lfht *ht) | |
1893 | { | |
1894 | unsigned long new_size, old_size; | |
4105056a MD |
1895 | |
1896 | /* | |
1897 | * Resize table, re-do if the target size has changed under us. | |
1898 | */ | |
1899 | do { | |
d2be3620 MD |
1900 | assert(uatomic_read(&ht->in_progress_resize)); |
1901 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
1902 | break; | |
7b3893e4 LJ |
1903 | ht->resize_initiated = 1; |
1904 | old_size = ht->size; | |
1905 | new_size = CMM_LOAD_SHARED(ht->resize_target); | |
4105056a MD |
1906 | if (old_size < new_size) |
1907 | _do_cds_lfht_grow(ht, old_size, new_size); | |
1908 | else if (old_size > new_size) | |
1909 | _do_cds_lfht_shrink(ht, old_size, new_size); | |
7b3893e4 | 1910 | ht->resize_initiated = 0; |
4105056a MD |
1911 | /* write resize_initiated before read resize_target */ |
1912 | cmm_smp_mb(); | |
7b3893e4 | 1913 | } while (ht->size != CMM_LOAD_SHARED(ht->resize_target)); |
1475579c MD |
1914 | } |
1915 | ||
abc490a1 | 1916 | static |
ab65b890 | 1917 | unsigned long resize_target_grow(struct cds_lfht *ht, unsigned long new_size) |
464a1ec9 | 1918 | { |
7b3893e4 | 1919 | return _uatomic_xchg_monotonic_increase(&ht->resize_target, new_size); |
464a1ec9 MD |
1920 | } |
1921 | ||
1475579c | 1922 | static |
4105056a | 1923 | void resize_target_update_count(struct cds_lfht *ht, |
b8af5011 | 1924 | unsigned long count) |
1475579c | 1925 | { |
d0d8f9aa | 1926 | count = max(count, MIN_TABLE_SIZE); |
747d725c | 1927 | count = min(count, ht->max_nr_buckets); |
7b3893e4 | 1928 | uatomic_set(&ht->resize_target, count); |
1475579c MD |
1929 | } |
1930 | ||
1931 | void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size) | |
464a1ec9 | 1932 | { |
a1e5e232 MD |
1933 | int was_online; |
1934 | ||
a1e5e232 MD |
1935 | was_online = ht->flavor->read_ongoing(); |
1936 | if (was_online) | |
1937 | ht->flavor->thread_offline(); | |
10e68472 MD |
1938 | /* Calling with RCU read-side held is an error. */ |
1939 | if (ht->flavor->read_ongoing()) { | |
1940 | static int print_once; | |
1941 | ||
1942 | if (!CMM_LOAD_SHARED(print_once)) | |
1943 | fprintf(stderr, "[error] rculfhash: cds_lfht_resize " | |
1944 | "called with RCU read-side lock held.\n"); | |
1945 | CMM_STORE_SHARED(print_once, 1); | |
1946 | assert(0); | |
1947 | goto end; | |
1948 | } | |
1949 | resize_target_update_count(ht, new_size); | |
1950 | CMM_STORE_SHARED(ht->resize_initiated, 1); | |
1475579c MD |
1951 | pthread_mutex_lock(&ht->resize_mutex); |
1952 | _do_cds_lfht_resize(ht); | |
1953 | pthread_mutex_unlock(&ht->resize_mutex); | |
10e68472 | 1954 | end: |
a1e5e232 MD |
1955 | if (was_online) |
1956 | ht->flavor->thread_online(); | |
abc490a1 | 1957 | } |
464a1ec9 | 1958 | |
abc490a1 MD |
1959 | static |
1960 | void do_resize_cb(struct rcu_head *head) | |
1961 | { | |
1962 | struct rcu_resize_work *work = | |
1963 | caa_container_of(head, struct rcu_resize_work, head); | |
14044b37 | 1964 | struct cds_lfht *ht = work->ht; |
abc490a1 | 1965 | |
7b17c13e | 1966 | ht->flavor->thread_offline(); |
abc490a1 | 1967 | pthread_mutex_lock(&ht->resize_mutex); |
14044b37 | 1968 | _do_cds_lfht_resize(ht); |
abc490a1 | 1969 | pthread_mutex_unlock(&ht->resize_mutex); |
7b17c13e | 1970 | ht->flavor->thread_online(); |
98808fb1 | 1971 | poison_free(work); |
848d4088 MD |
1972 | cmm_smp_mb(); /* finish resize before decrement */ |
1973 | uatomic_dec(&ht->in_progress_resize); | |
464a1ec9 MD |
1974 | } |
1975 | ||
abc490a1 | 1976 | static |
f1f119ee | 1977 | void __cds_lfht_resize_lazy_launch(struct cds_lfht *ht) |
ab7d5fc6 | 1978 | { |
abc490a1 MD |
1979 | struct rcu_resize_work *work; |
1980 | ||
4105056a MD |
1981 | /* Store resize_target before read resize_initiated */ |
1982 | cmm_smp_mb(); | |
7b3893e4 | 1983 | if (!CMM_LOAD_SHARED(ht->resize_initiated)) { |
848d4088 | 1984 | uatomic_inc(&ht->in_progress_resize); |
59290e9d | 1985 | cmm_smp_mb(); /* increment resize count before load destroy */ |
ed35e6d8 MD |
1986 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) { |
1987 | uatomic_dec(&ht->in_progress_resize); | |
59290e9d | 1988 | return; |
ed35e6d8 | 1989 | } |
f9830efd | 1990 | work = malloc(sizeof(*work)); |
741f378e MD |
1991 | if (work == NULL) { |
1992 | dbg_printf("error allocating resize work, bailing out\n"); | |
1993 | uatomic_dec(&ht->in_progress_resize); | |
1994 | return; | |
1995 | } | |
f9830efd | 1996 | work->ht = ht; |
7b17c13e | 1997 | ht->flavor->update_call_rcu(&work->head, do_resize_cb); |
7b3893e4 | 1998 | CMM_STORE_SHARED(ht->resize_initiated, 1); |
f9830efd | 1999 | } |
ab7d5fc6 | 2000 | } |
3171717f | 2001 | |
f1f119ee LJ |
2002 | static |
2003 | void cds_lfht_resize_lazy_grow(struct cds_lfht *ht, unsigned long size, int growth) | |
2004 | { | |
2005 | unsigned long target_size = size << growth; | |
2006 | ||
747d725c | 2007 | target_size = min(target_size, ht->max_nr_buckets); |
f1f119ee LJ |
2008 | if (resize_target_grow(ht, target_size) >= target_size) |
2009 | return; | |
2010 | ||
2011 | __cds_lfht_resize_lazy_launch(ht); | |
2012 | } | |
2013 | ||
89bb121d LJ |
2014 | /* |
2015 | * We favor grow operations over shrink. A shrink operation never occurs | |
2016 | * if a grow operation is queued for lazy execution. A grow operation | |
2017 | * cancels any pending shrink lazy execution. | |
2018 | */ | |
3171717f | 2019 | static |
4105056a | 2020 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, |
3171717f MD |
2021 | unsigned long count) |
2022 | { | |
b8af5011 MD |
2023 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) |
2024 | return; | |
d0d8f9aa | 2025 | count = max(count, MIN_TABLE_SIZE); |
747d725c | 2026 | count = min(count, ht->max_nr_buckets); |
89bb121d LJ |
2027 | if (count == size) |
2028 | return; /* Already the right size, no resize needed */ | |
2029 | if (count > size) { /* lazy grow */ | |
2030 | if (resize_target_grow(ht, count) >= count) | |
2031 | return; | |
2032 | } else { /* lazy shrink */ | |
2033 | for (;;) { | |
2034 | unsigned long s; | |
2035 | ||
7b3893e4 | 2036 | s = uatomic_cmpxchg(&ht->resize_target, size, count); |
89bb121d LJ |
2037 | if (s == size) |
2038 | break; /* no resize needed */ | |
2039 | if (s > size) | |
2040 | return; /* growing is/(was just) in progress */ | |
2041 | if (s <= count) | |
2042 | return; /* some other thread do shrink */ | |
2043 | size = s; | |
2044 | } | |
2045 | } | |
f1f119ee | 2046 | __cds_lfht_resize_lazy_launch(ht); |
3171717f | 2047 | } |