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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 | |
37 | * table lookups and use the returned objects safely by delaying | |
38 | * memory reclaim of a grace period. | |
39 | * - Add and remove operations are lock-free, and do not need to | |
40 | * allocate memory. They need to be executed within RCU read-side | |
41 | * critical section to ensure the objects they read are valid and to | |
42 | * deal with the cmpxchg ABA problem. | |
43 | * - add and add_unique operations are supported. add_unique checks if | |
44 | * the node key already exists in the hash table. It ensures no key | |
45 | * duplicata exists. | |
46 | * - The resize operation executes concurrently with add/remove/lookup. | |
47 | * - Hash table nodes are contained within a split-ordered list. This | |
48 | * list is ordered by incrementing reversed-bits-hash value. | |
1ee8f000 | 49 | * - An index of bucket nodes is kept. These bucket nodes are the hash |
e753ff5a MD |
50 | * table "buckets", and they are also chained together in the |
51 | * split-ordered list, which allows recursive expansion. | |
1475579c MD |
52 | * - The resize operation for small tables only allows expanding the hash table. |
53 | * It is triggered automatically by detecting long chains in the add | |
54 | * operation. | |
55 | * - The resize operation for larger tables (and available through an | |
56 | * API) allows both expanding and shrinking the hash table. | |
4c42f1b8 | 57 | * - Split-counters are used to keep track of the number of |
1475579c | 58 | * nodes within the hash table for automatic resize triggering. |
e753ff5a MD |
59 | * - Resize operation initiated by long chain detection is executed by a |
60 | * call_rcu thread, which keeps lock-freedom of add and remove. | |
61 | * - Resize operations are protected by a mutex. | |
62 | * - The removal operation is split in two parts: first, a "removed" | |
63 | * flag is set in the next pointer within the node to remove. Then, | |
64 | * a "garbage collection" is performed in the bucket containing the | |
65 | * removed node (from the start of the bucket up to the removed node). | |
66 | * All encountered nodes with "removed" flag set in their next | |
67 | * pointers are removed from the linked-list. If the cmpxchg used for | |
68 | * removal fails (due to concurrent garbage-collection or concurrent | |
69 | * add), we retry from the beginning of the bucket. This ensures that | |
70 | * the node with "removed" flag set is removed from the hash table | |
71 | * (not visible to lookups anymore) before the RCU read-side critical | |
72 | * section held across removal ends. Furthermore, this ensures that | |
73 | * the node with "removed" flag set is removed from the linked-list | |
74 | * before its memory is reclaimed. Only the thread which removal | |
75 | * successfully set the "removed" flag (with a cmpxchg) into a node's | |
76 | * next pointer is considered to have succeeded its removal (and thus | |
77 | * owns the node to reclaim). Because we garbage-collect starting from | |
1ee8f000 | 78 | * an invariant node (the start-of-bucket bucket node) up to the |
e753ff5a MD |
79 | * "removed" node (or find a reverse-hash that is higher), we are sure |
80 | * that a successful traversal of the chain leads to a chain that is | |
81 | * present in the linked-list (the start node is never removed) and | |
82 | * that is does not contain the "removed" node anymore, even if | |
83 | * concurrent delete/add operations are changing the structure of the | |
84 | * list concurrently. | |
29e669f6 MD |
85 | * - The add operation performs gargage collection of buckets if it |
86 | * encounters nodes with removed flag set in the bucket where it wants | |
87 | * to add its new node. This ensures lock-freedom of add operation by | |
88 | * helping the remover unlink nodes from the list rather than to wait | |
89 | * for it do to so. | |
e753ff5a MD |
90 | * - A RCU "order table" indexed by log2(hash index) is copied and |
91 | * expanded by the resize operation. This order table allows finding | |
1ee8f000 LJ |
92 | * the "bucket node" tables. |
93 | * - There is one bucket node table per hash index order. The size of | |
94 | * each bucket node table is half the number of hashes contained in | |
93d46c39 | 95 | * this order (except for order 0). |
1ee8f000 LJ |
96 | * - synchronzie_rcu is used to garbage-collect the old bucket node table. |
97 | * - The per-order bucket node tables contain a compact version of the | |
e753ff5a MD |
98 | * hash table nodes. These tables are invariant after they are |
99 | * populated into the hash table. | |
93d46c39 | 100 | * |
1ee8f000 | 101 | * Bucket node tables: |
93d46c39 | 102 | * |
1ee8f000 LJ |
103 | * hash table hash table the last all bucket node tables |
104 | * order size bucket node 0 1 2 3 4 5 6(index) | |
93d46c39 LJ |
105 | * table size |
106 | * 0 1 1 1 | |
107 | * 1 2 1 1 1 | |
108 | * 2 4 2 1 1 2 | |
109 | * 3 8 4 1 1 2 4 | |
110 | * 4 16 8 1 1 2 4 8 | |
111 | * 5 32 16 1 1 2 4 8 16 | |
112 | * 6 64 32 1 1 2 4 8 16 32 | |
113 | * | |
1ee8f000 | 114 | * When growing/shrinking, we only focus on the last bucket node table |
93d46c39 LJ |
115 | * which size is (!order ? 1 : (1 << (order -1))). |
116 | * | |
117 | * Example for growing/shrinking: | |
1ee8f000 LJ |
118 | * grow hash table from order 5 to 6: init the index=6 bucket node table |
119 | * shrink hash table from order 6 to 5: fini the index=6 bucket node table | |
93d46c39 | 120 | * |
1475579c MD |
121 | * A bit of ascii art explanation: |
122 | * | |
123 | * Order index is the off-by-one compare to the actual power of 2 because | |
124 | * we use index 0 to deal with the 0 special-case. | |
125 | * | |
126 | * This shows the nodes for a small table ordered by reversed bits: | |
127 | * | |
128 | * bits reverse | |
129 | * 0 000 000 | |
130 | * 4 100 001 | |
131 | * 2 010 010 | |
132 | * 6 110 011 | |
133 | * 1 001 100 | |
134 | * 5 101 101 | |
135 | * 3 011 110 | |
136 | * 7 111 111 | |
137 | * | |
138 | * This shows the nodes in order of non-reversed bits, linked by | |
139 | * reversed-bit order. | |
140 | * | |
141 | * order bits reverse | |
142 | * 0 0 000 000 | |
0adc36a8 LJ |
143 | * 1 | 1 001 100 <- |
144 | * 2 | | 2 010 010 <- | | |
f6fdd688 | 145 | * | | | 3 011 110 | <- | |
1475579c MD |
146 | * 3 -> | | | 4 100 001 | | |
147 | * -> | | 5 101 101 | | |
148 | * -> | 6 110 011 | |
149 | * -> 7 111 111 | |
e753ff5a MD |
150 | */ |
151 | ||
2ed95849 MD |
152 | #define _LGPL_SOURCE |
153 | #include <stdlib.h> | |
e0ba718a MD |
154 | #include <errno.h> |
155 | #include <assert.h> | |
156 | #include <stdio.h> | |
abc490a1 | 157 | #include <stdint.h> |
f000907d | 158 | #include <string.h> |
e0ba718a | 159 | |
15cfbec7 | 160 | #include "config.h" |
2ed95849 | 161 | #include <urcu.h> |
abc490a1 | 162 | #include <urcu-call-rcu.h> |
a42cc659 MD |
163 | #include <urcu/arch.h> |
164 | #include <urcu/uatomic.h> | |
a42cc659 | 165 | #include <urcu/compiler.h> |
abc490a1 | 166 | #include <urcu/rculfhash.h> |
5e28c532 | 167 | #include <stdio.h> |
464a1ec9 | 168 | #include <pthread.h> |
44395fb7 | 169 | |
f9830efd | 170 | #ifdef DEBUG |
f0c29ed7 | 171 | #define dbg_printf(fmt, args...) printf("[debug rculfhash] " fmt, ## args) |
f9830efd | 172 | #else |
e753ff5a | 173 | #define dbg_printf(fmt, args...) |
f9830efd MD |
174 | #endif |
175 | ||
f8994aee | 176 | /* |
4c42f1b8 | 177 | * Split-counters lazily update the global counter each 1024 |
f8994aee MD |
178 | * addition/removal. It automatically keeps track of resize required. |
179 | * We use the bucket length as indicator for need to expand for small | |
180 | * tables and machines lacking per-cpu data suppport. | |
181 | */ | |
182 | #define COUNT_COMMIT_ORDER 10 | |
4ddbb355 | 183 | #define DEFAULT_SPLIT_COUNT_MASK 0xFUL |
6ea6bc67 MD |
184 | #define CHAIN_LEN_TARGET 1 |
185 | #define CHAIN_LEN_RESIZE_THRESHOLD 3 | |
2ed95849 | 186 | |
cd95516d | 187 | /* |
76a73da8 | 188 | * Define the minimum table size. |
cd95516d | 189 | */ |
d0d8f9aa LJ |
190 | #define MIN_TABLE_ORDER 0 |
191 | #define MIN_TABLE_SIZE (1UL << MIN_TABLE_ORDER) | |
cd95516d | 192 | |
4105056a MD |
193 | #if (CAA_BITS_PER_LONG == 32) |
194 | #define MAX_TABLE_ORDER 32 | |
195 | #else | |
196 | #define MAX_TABLE_ORDER 64 | |
197 | #endif | |
198 | ||
b7d619b0 | 199 | /* |
1ee8f000 | 200 | * Minimum number of bucket nodes to touch per thread to parallelize grow/shrink. |
b7d619b0 | 201 | */ |
6083a889 MD |
202 | #define MIN_PARTITION_PER_THREAD_ORDER 12 |
203 | #define MIN_PARTITION_PER_THREAD (1UL << MIN_PARTITION_PER_THREAD_ORDER) | |
b7d619b0 | 204 | |
4105056a MD |
205 | #ifndef min |
206 | #define min(a, b) ((a) < (b) ? (a) : (b)) | |
207 | #endif | |
208 | ||
abc490a1 MD |
209 | #ifndef max |
210 | #define max(a, b) ((a) > (b) ? (a) : (b)) | |
211 | #endif | |
2ed95849 | 212 | |
d95bd160 MD |
213 | /* |
214 | * The removed flag needs to be updated atomically with the pointer. | |
48ed1c18 | 215 | * It indicates that no node must attach to the node scheduled for |
b198f0fd | 216 | * removal, and that node garbage collection must be performed. |
1ee8f000 | 217 | * The bucket flag does not require to be updated atomically with the |
d95bd160 MD |
218 | * pointer, but it is added as a pointer low bit flag to save space. |
219 | */ | |
d37166c6 | 220 | #define REMOVED_FLAG (1UL << 0) |
1ee8f000 | 221 | #define BUCKET_FLAG (1UL << 1) |
b198f0fd | 222 | #define FLAGS_MASK ((1UL << 2) - 1) |
d37166c6 | 223 | |
bb7b2f26 | 224 | /* Value of the end pointer. Should not interact with flags. */ |
f9c80341 | 225 | #define END_VALUE NULL |
bb7b2f26 | 226 | |
7f52427b MD |
227 | /* |
228 | * ht_items_count: Split-counters counting the number of node addition | |
229 | * and removal in the table. Only used if the CDS_LFHT_ACCOUNTING flag | |
230 | * is set at hash table creation. | |
231 | * | |
232 | * These are free-running counters, never reset to zero. They count the | |
233 | * number of add/remove, and trigger every (1 << COUNT_COMMIT_ORDER) | |
234 | * operations to update the global counter. We choose a power-of-2 value | |
235 | * for the trigger to deal with 32 or 64-bit overflow of the counter. | |
236 | */ | |
df44348d | 237 | struct ht_items_count { |
860d07e8 | 238 | unsigned long add, del; |
df44348d MD |
239 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
240 | ||
7f52427b MD |
241 | /* |
242 | * rcu_table: Contains the size and desired new size if a resize | |
243 | * operation is in progress, as well as the statically-sized array of | |
dcc26ef4 | 244 | * bucket table pointers. |
7f52427b | 245 | */ |
395270b6 | 246 | struct rcu_table { |
4105056a | 247 | unsigned long size; /* always a power of 2, shared (RCU) */ |
f9830efd | 248 | unsigned long resize_target; |
11519af6 | 249 | int resize_initiated; |
dcc26ef4 LJ |
250 | |
251 | /* | |
252 | * Contains the per order-index-level bucket node table. The size | |
253 | * of each bucket node table is half the number of hashes contained | |
254 | * in this order (except for order 0). The minimum allocation size | |
255 | * parameter allows combining the bucket node arrays of the lowermost | |
256 | * levels to improve cache locality for small index orders. | |
257 | */ | |
258 | struct cds_lfht_node *tbl[MAX_TABLE_ORDER]; | |
395270b6 MD |
259 | }; |
260 | ||
7f52427b MD |
261 | /* |
262 | * cds_lfht: Top-level data structure representing a lock-free hash | |
263 | * table. Defined in the implementation file to make it be an opaque | |
264 | * cookie to users. | |
265 | */ | |
14044b37 | 266 | struct cds_lfht { |
4105056a | 267 | struct rcu_table t; |
5488222b LJ |
268 | unsigned long min_alloc_order; |
269 | unsigned long min_alloc_size; | |
b8af5011 | 270 | int flags; |
5f511391 MD |
271 | /* |
272 | * We need to put the work threads offline (QSBR) when taking this | |
273 | * mutex, because we use synchronize_rcu within this mutex critical | |
274 | * section, which waits on read-side critical sections, and could | |
275 | * therefore cause grace-period deadlock if we hold off RCU G.P. | |
276 | * completion. | |
277 | */ | |
464a1ec9 | 278 | pthread_mutex_t resize_mutex; /* resize mutex: add/del mutex */ |
33c7c748 | 279 | unsigned int in_progress_resize, in_progress_destroy; |
14044b37 | 280 | void (*cds_lfht_call_rcu)(struct rcu_head *head, |
abc490a1 | 281 | void (*func)(struct rcu_head *head)); |
1475579c | 282 | void (*cds_lfht_synchronize_rcu)(void); |
01dbfa62 MD |
283 | void (*cds_lfht_rcu_read_lock)(void); |
284 | void (*cds_lfht_rcu_read_unlock)(void); | |
5f511391 MD |
285 | void (*cds_lfht_rcu_thread_offline)(void); |
286 | void (*cds_lfht_rcu_thread_online)(void); | |
b7d619b0 MD |
287 | void (*cds_lfht_rcu_register_thread)(void); |
288 | void (*cds_lfht_rcu_unregister_thread)(void); | |
289 | pthread_attr_t *resize_attr; /* Resize threads attributes */ | |
7de5ccfd | 290 | long count; /* global approximate item count */ |
4c42f1b8 | 291 | struct ht_items_count *split_count; /* split item count */ |
2ed95849 MD |
292 | }; |
293 | ||
7f52427b MD |
294 | /* |
295 | * rcu_resize_work: Contains arguments passed to RCU worker thread | |
296 | * responsible for performing lazy resize. | |
297 | */ | |
abc490a1 MD |
298 | struct rcu_resize_work { |
299 | struct rcu_head head; | |
14044b37 | 300 | struct cds_lfht *ht; |
abc490a1 | 301 | }; |
2ed95849 | 302 | |
7f52427b MD |
303 | /* |
304 | * partition_resize_work: Contains arguments passed to worker threads | |
305 | * executing the hash table resize on partitions of the hash table | |
306 | * assigned to each processor's worker thread. | |
307 | */ | |
b7d619b0 | 308 | struct partition_resize_work { |
1af6e26e | 309 | pthread_t thread_id; |
b7d619b0 MD |
310 | struct cds_lfht *ht; |
311 | unsigned long i, start, len; | |
312 | void (*fct)(struct cds_lfht *ht, unsigned long i, | |
313 | unsigned long start, unsigned long len); | |
314 | }; | |
315 | ||
76a73da8 | 316 | static |
83beee94 | 317 | void _cds_lfht_add(struct cds_lfht *ht, |
0422d92c | 318 | cds_lfht_match_fct match, |
996ff57c | 319 | const void *key, |
83beee94 MD |
320 | unsigned long size, |
321 | struct cds_lfht_node *node, | |
322 | struct cds_lfht_iter *unique_ret, | |
1ee8f000 | 323 | int bucket); |
48ed1c18 | 324 | |
abc490a1 MD |
325 | /* |
326 | * Algorithm to reverse bits in a word by lookup table, extended to | |
327 | * 64-bit words. | |
f9830efd | 328 | * Source: |
abc490a1 | 329 | * http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable |
f9830efd | 330 | * Originally from Public Domain. |
abc490a1 MD |
331 | */ |
332 | ||
333 | static const uint8_t BitReverseTable256[256] = | |
2ed95849 | 334 | { |
abc490a1 MD |
335 | #define R2(n) (n), (n) + 2*64, (n) + 1*64, (n) + 3*64 |
336 | #define R4(n) R2(n), R2((n) + 2*16), R2((n) + 1*16), R2((n) + 3*16) | |
337 | #define R6(n) R4(n), R4((n) + 2*4 ), R4((n) + 1*4 ), R4((n) + 3*4 ) | |
338 | R6(0), R6(2), R6(1), R6(3) | |
339 | }; | |
340 | #undef R2 | |
341 | #undef R4 | |
342 | #undef R6 | |
2ed95849 | 343 | |
abc490a1 MD |
344 | static |
345 | uint8_t bit_reverse_u8(uint8_t v) | |
346 | { | |
347 | return BitReverseTable256[v]; | |
348 | } | |
ab7d5fc6 | 349 | |
abc490a1 MD |
350 | static __attribute__((unused)) |
351 | uint32_t bit_reverse_u32(uint32_t v) | |
352 | { | |
353 | return ((uint32_t) bit_reverse_u8(v) << 24) | | |
354 | ((uint32_t) bit_reverse_u8(v >> 8) << 16) | | |
355 | ((uint32_t) bit_reverse_u8(v >> 16) << 8) | | |
356 | ((uint32_t) bit_reverse_u8(v >> 24)); | |
2ed95849 MD |
357 | } |
358 | ||
abc490a1 MD |
359 | static __attribute__((unused)) |
360 | uint64_t bit_reverse_u64(uint64_t v) | |
2ed95849 | 361 | { |
abc490a1 MD |
362 | return ((uint64_t) bit_reverse_u8(v) << 56) | |
363 | ((uint64_t) bit_reverse_u8(v >> 8) << 48) | | |
364 | ((uint64_t) bit_reverse_u8(v >> 16) << 40) | | |
365 | ((uint64_t) bit_reverse_u8(v >> 24) << 32) | | |
366 | ((uint64_t) bit_reverse_u8(v >> 32) << 24) | | |
367 | ((uint64_t) bit_reverse_u8(v >> 40) << 16) | | |
368 | ((uint64_t) bit_reverse_u8(v >> 48) << 8) | | |
369 | ((uint64_t) bit_reverse_u8(v >> 56)); | |
370 | } | |
371 | ||
372 | static | |
373 | unsigned long bit_reverse_ulong(unsigned long v) | |
374 | { | |
375 | #if (CAA_BITS_PER_LONG == 32) | |
376 | return bit_reverse_u32(v); | |
377 | #else | |
378 | return bit_reverse_u64(v); | |
379 | #endif | |
380 | } | |
381 | ||
f9830efd | 382 | /* |
24365af7 MD |
383 | * fls: returns the position of the most significant bit. |
384 | * Returns 0 if no bit is set, else returns the position of the most | |
385 | * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit). | |
f9830efd | 386 | */ |
24365af7 MD |
387 | #if defined(__i386) || defined(__x86_64) |
388 | static inline | |
389 | unsigned int fls_u32(uint32_t x) | |
f9830efd | 390 | { |
24365af7 MD |
391 | int r; |
392 | ||
393 | asm("bsrl %1,%0\n\t" | |
394 | "jnz 1f\n\t" | |
395 | "movl $-1,%0\n\t" | |
396 | "1:\n\t" | |
397 | : "=r" (r) : "rm" (x)); | |
398 | return r + 1; | |
399 | } | |
400 | #define HAS_FLS_U32 | |
401 | #endif | |
402 | ||
403 | #if defined(__x86_64) | |
404 | static inline | |
405 | unsigned int fls_u64(uint64_t x) | |
406 | { | |
407 | long r; | |
408 | ||
409 | asm("bsrq %1,%0\n\t" | |
410 | "jnz 1f\n\t" | |
411 | "movq $-1,%0\n\t" | |
412 | "1:\n\t" | |
413 | : "=r" (r) : "rm" (x)); | |
414 | return r + 1; | |
415 | } | |
416 | #define HAS_FLS_U64 | |
417 | #endif | |
418 | ||
419 | #ifndef HAS_FLS_U64 | |
420 | static __attribute__((unused)) | |
421 | unsigned int fls_u64(uint64_t x) | |
422 | { | |
423 | unsigned int r = 64; | |
424 | ||
425 | if (!x) | |
426 | return 0; | |
427 | ||
428 | if (!(x & 0xFFFFFFFF00000000ULL)) { | |
429 | x <<= 32; | |
430 | r -= 32; | |
431 | } | |
432 | if (!(x & 0xFFFF000000000000ULL)) { | |
433 | x <<= 16; | |
434 | r -= 16; | |
435 | } | |
436 | if (!(x & 0xFF00000000000000ULL)) { | |
437 | x <<= 8; | |
438 | r -= 8; | |
439 | } | |
440 | if (!(x & 0xF000000000000000ULL)) { | |
441 | x <<= 4; | |
442 | r -= 4; | |
443 | } | |
444 | if (!(x & 0xC000000000000000ULL)) { | |
445 | x <<= 2; | |
446 | r -= 2; | |
447 | } | |
448 | if (!(x & 0x8000000000000000ULL)) { | |
449 | x <<= 1; | |
450 | r -= 1; | |
451 | } | |
452 | return r; | |
453 | } | |
454 | #endif | |
455 | ||
456 | #ifndef HAS_FLS_U32 | |
457 | static __attribute__((unused)) | |
458 | unsigned int fls_u32(uint32_t x) | |
459 | { | |
460 | unsigned int r = 32; | |
f9830efd | 461 | |
24365af7 MD |
462 | if (!x) |
463 | return 0; | |
464 | if (!(x & 0xFFFF0000U)) { | |
465 | x <<= 16; | |
466 | r -= 16; | |
467 | } | |
468 | if (!(x & 0xFF000000U)) { | |
469 | x <<= 8; | |
470 | r -= 8; | |
471 | } | |
472 | if (!(x & 0xF0000000U)) { | |
473 | x <<= 4; | |
474 | r -= 4; | |
475 | } | |
476 | if (!(x & 0xC0000000U)) { | |
477 | x <<= 2; | |
478 | r -= 2; | |
479 | } | |
480 | if (!(x & 0x80000000U)) { | |
481 | x <<= 1; | |
482 | r -= 1; | |
483 | } | |
484 | return r; | |
485 | } | |
486 | #endif | |
487 | ||
488 | unsigned int fls_ulong(unsigned long x) | |
f9830efd | 489 | { |
6887cc5e | 490 | #if (CAA_BITS_PER_LONG == 32) |
24365af7 MD |
491 | return fls_u32(x); |
492 | #else | |
493 | return fls_u64(x); | |
494 | #endif | |
495 | } | |
f9830efd | 496 | |
920f8ef6 LJ |
497 | /* |
498 | * Return the minimum order for which x <= (1UL << order). | |
499 | * Return -1 if x is 0. | |
500 | */ | |
24365af7 MD |
501 | int get_count_order_u32(uint32_t x) |
502 | { | |
920f8ef6 LJ |
503 | if (!x) |
504 | return -1; | |
24365af7 | 505 | |
920f8ef6 | 506 | return fls_u32(x - 1); |
24365af7 MD |
507 | } |
508 | ||
920f8ef6 LJ |
509 | /* |
510 | * Return the minimum order for which x <= (1UL << order). | |
511 | * Return -1 if x is 0. | |
512 | */ | |
24365af7 MD |
513 | int get_count_order_ulong(unsigned long x) |
514 | { | |
920f8ef6 LJ |
515 | if (!x) |
516 | return -1; | |
24365af7 | 517 | |
920f8ef6 | 518 | return fls_ulong(x - 1); |
f9830efd MD |
519 | } |
520 | ||
98808fb1 | 521 | #ifdef POISON_FREE |
5afadd12 LJ |
522 | #define poison_free(ptr) \ |
523 | do { \ | |
524 | if (ptr) { \ | |
525 | memset(ptr, 0x42, sizeof(*(ptr))); \ | |
526 | free(ptr); \ | |
527 | } \ | |
98808fb1 MD |
528 | } while (0) |
529 | #else | |
530 | #define poison_free(ptr) free(ptr) | |
531 | #endif | |
532 | ||
f9830efd | 533 | static |
ab65b890 | 534 | void cds_lfht_resize_lazy_grow(struct cds_lfht *ht, unsigned long size, int growth); |
f9830efd | 535 | |
f8994aee | 536 | static |
4105056a | 537 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, |
f8994aee MD |
538 | unsigned long count); |
539 | ||
df44348d | 540 | static long nr_cpus_mask = -1; |
4c42f1b8 LJ |
541 | static long split_count_mask = -1; |
542 | ||
4ddbb355 | 543 | #if defined(HAVE_SYSCONF) |
4c42f1b8 LJ |
544 | static void ht_init_nr_cpus_mask(void) |
545 | { | |
546 | long maxcpus; | |
547 | ||
548 | maxcpus = sysconf(_SC_NPROCESSORS_CONF); | |
549 | if (maxcpus <= 0) { | |
550 | nr_cpus_mask = -2; | |
551 | return; | |
552 | } | |
553 | /* | |
554 | * round up number of CPUs to next power of two, so we | |
555 | * can use & for modulo. | |
556 | */ | |
557 | maxcpus = 1UL << get_count_order_ulong(maxcpus); | |
558 | nr_cpus_mask = maxcpus - 1; | |
559 | } | |
4ddbb355 LJ |
560 | #else /* #if defined(HAVE_SYSCONF) */ |
561 | static void ht_init_nr_cpus_mask(void) | |
562 | { | |
563 | nr_cpus_mask = -2; | |
564 | } | |
565 | #endif /* #else #if defined(HAVE_SYSCONF) */ | |
df44348d MD |
566 | |
567 | static | |
5afadd12 | 568 | void alloc_split_items_count(struct cds_lfht *ht) |
df44348d MD |
569 | { |
570 | struct ht_items_count *count; | |
571 | ||
4c42f1b8 LJ |
572 | if (nr_cpus_mask == -1) { |
573 | ht_init_nr_cpus_mask(); | |
4ddbb355 LJ |
574 | if (nr_cpus_mask < 0) |
575 | split_count_mask = DEFAULT_SPLIT_COUNT_MASK; | |
576 | else | |
577 | split_count_mask = nr_cpus_mask; | |
df44348d | 578 | } |
4c42f1b8 | 579 | |
4ddbb355 | 580 | assert(split_count_mask >= 0); |
5afadd12 LJ |
581 | |
582 | if (ht->flags & CDS_LFHT_ACCOUNTING) { | |
583 | ht->split_count = calloc(split_count_mask + 1, sizeof(*count)); | |
584 | assert(ht->split_count); | |
585 | } else { | |
586 | ht->split_count = NULL; | |
587 | } | |
df44348d MD |
588 | } |
589 | ||
590 | static | |
5afadd12 | 591 | void free_split_items_count(struct cds_lfht *ht) |
df44348d | 592 | { |
5afadd12 | 593 | poison_free(ht->split_count); |
df44348d MD |
594 | } |
595 | ||
14360f1c | 596 | #if defined(HAVE_SCHED_GETCPU) |
df44348d | 597 | static |
14360f1c | 598 | int ht_get_split_count_index(unsigned long hash) |
df44348d MD |
599 | { |
600 | int cpu; | |
601 | ||
4c42f1b8 | 602 | assert(split_count_mask >= 0); |
df44348d | 603 | cpu = sched_getcpu(); |
8ed51e04 | 604 | if (caa_unlikely(cpu < 0)) |
14360f1c | 605 | return hash & split_count_mask; |
df44348d | 606 | else |
4c42f1b8 | 607 | return cpu & split_count_mask; |
df44348d | 608 | } |
14360f1c LJ |
609 | #else /* #if defined(HAVE_SCHED_GETCPU) */ |
610 | static | |
611 | int ht_get_split_count_index(unsigned long hash) | |
612 | { | |
613 | return hash & split_count_mask; | |
614 | } | |
615 | #endif /* #else #if defined(HAVE_SCHED_GETCPU) */ | |
df44348d MD |
616 | |
617 | static | |
14360f1c | 618 | void ht_count_add(struct cds_lfht *ht, unsigned long size, unsigned long hash) |
df44348d | 619 | { |
4c42f1b8 LJ |
620 | unsigned long split_count; |
621 | int index; | |
df44348d | 622 | |
8ed51e04 | 623 | if (caa_unlikely(!ht->split_count)) |
3171717f | 624 | return; |
14360f1c | 625 | index = ht_get_split_count_index(hash); |
4c42f1b8 | 626 | split_count = uatomic_add_return(&ht->split_count[index].add, 1); |
8ed51e04 | 627 | if (caa_unlikely(!(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) { |
e3ecefd6 | 628 | long count; |
df44348d | 629 | |
4c42f1b8 | 630 | dbg_printf("add split count %lu\n", split_count); |
df44348d MD |
631 | count = uatomic_add_return(&ht->count, |
632 | 1UL << COUNT_COMMIT_ORDER); | |
633 | /* If power of 2 */ | |
634 | if (!(count & (count - 1))) { | |
4105056a | 635 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) < size) |
f8994aee | 636 | return; |
e3ecefd6 | 637 | dbg_printf("add set global %ld\n", count); |
4105056a | 638 | cds_lfht_resize_lazy_count(ht, size, |
6ea6bc67 | 639 | count >> (CHAIN_LEN_TARGET - 1)); |
df44348d MD |
640 | } |
641 | } | |
642 | } | |
643 | ||
644 | static | |
14360f1c | 645 | void ht_count_del(struct cds_lfht *ht, unsigned long size, unsigned long hash) |
df44348d | 646 | { |
4c42f1b8 LJ |
647 | unsigned long split_count; |
648 | int index; | |
df44348d | 649 | |
8ed51e04 | 650 | if (caa_unlikely(!ht->split_count)) |
3171717f | 651 | return; |
14360f1c | 652 | index = ht_get_split_count_index(hash); |
4c42f1b8 | 653 | split_count = uatomic_add_return(&ht->split_count[index].del, 1); |
8ed51e04 | 654 | if (caa_unlikely(!(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) { |
e3ecefd6 | 655 | long count; |
df44348d | 656 | |
4c42f1b8 | 657 | dbg_printf("del split count %lu\n", split_count); |
df44348d | 658 | count = uatomic_add_return(&ht->count, |
3171717f | 659 | -(1UL << COUNT_COMMIT_ORDER)); |
df44348d MD |
660 | /* If power of 2 */ |
661 | if (!(count & (count - 1))) { | |
4105056a | 662 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) >= size) |
f8994aee | 663 | return; |
e3ecefd6 MD |
664 | dbg_printf("del set global %ld\n", count); |
665 | /* | |
c941bb9e | 666 | * Don't shrink table if the number of nodes is below a |
e3ecefd6 MD |
667 | * certain threshold. |
668 | */ | |
4c42f1b8 | 669 | if (count < (1UL << COUNT_COMMIT_ORDER) * (split_count_mask + 1)) |
e3ecefd6 | 670 | return; |
4105056a | 671 | cds_lfht_resize_lazy_count(ht, size, |
6ea6bc67 | 672 | count >> (CHAIN_LEN_TARGET - 1)); |
df44348d MD |
673 | } |
674 | } | |
675 | } | |
676 | ||
f9830efd | 677 | static |
4105056a | 678 | void check_resize(struct cds_lfht *ht, unsigned long size, uint32_t chain_len) |
f9830efd | 679 | { |
f8994aee MD |
680 | unsigned long count; |
681 | ||
b8af5011 MD |
682 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) |
683 | return; | |
f8994aee MD |
684 | count = uatomic_read(&ht->count); |
685 | /* | |
686 | * Use bucket-local length for small table expand and for | |
687 | * environments lacking per-cpu data support. | |
688 | */ | |
689 | if (count >= (1UL << COUNT_COMMIT_ORDER)) | |
690 | return; | |
24365af7 | 691 | if (chain_len > 100) |
f0c29ed7 | 692 | dbg_printf("WARNING: large chain length: %u.\n", |
24365af7 | 693 | chain_len); |
3390d470 | 694 | if (chain_len >= CHAIN_LEN_RESIZE_THRESHOLD) |
ab65b890 | 695 | cds_lfht_resize_lazy_grow(ht, size, |
01370f0b | 696 | get_count_order_u32(chain_len - (CHAIN_LEN_TARGET - 1))); |
f9830efd MD |
697 | } |
698 | ||
abc490a1 | 699 | static |
14044b37 | 700 | struct cds_lfht_node *clear_flag(struct cds_lfht_node *node) |
abc490a1 | 701 | { |
14044b37 | 702 | return (struct cds_lfht_node *) (((unsigned long) node) & ~FLAGS_MASK); |
abc490a1 MD |
703 | } |
704 | ||
705 | static | |
14044b37 | 706 | int is_removed(struct cds_lfht_node *node) |
abc490a1 | 707 | { |
d37166c6 | 708 | return ((unsigned long) node) & REMOVED_FLAG; |
abc490a1 MD |
709 | } |
710 | ||
711 | static | |
14044b37 | 712 | struct cds_lfht_node *flag_removed(struct cds_lfht_node *node) |
abc490a1 | 713 | { |
14044b37 | 714 | return (struct cds_lfht_node *) (((unsigned long) node) | REMOVED_FLAG); |
abc490a1 MD |
715 | } |
716 | ||
f5596c94 | 717 | static |
1ee8f000 | 718 | int is_bucket(struct cds_lfht_node *node) |
f5596c94 | 719 | { |
1ee8f000 | 720 | return ((unsigned long) node) & BUCKET_FLAG; |
f5596c94 MD |
721 | } |
722 | ||
723 | static | |
1ee8f000 | 724 | struct cds_lfht_node *flag_bucket(struct cds_lfht_node *node) |
f5596c94 | 725 | { |
1ee8f000 | 726 | return (struct cds_lfht_node *) (((unsigned long) node) | BUCKET_FLAG); |
f5596c94 | 727 | } |
bb7b2f26 MD |
728 | |
729 | static | |
730 | struct cds_lfht_node *get_end(void) | |
731 | { | |
732 | return (struct cds_lfht_node *) END_VALUE; | |
733 | } | |
734 | ||
735 | static | |
736 | int is_end(struct cds_lfht_node *node) | |
737 | { | |
738 | return clear_flag(node) == (struct cds_lfht_node *) END_VALUE; | |
739 | } | |
740 | ||
abc490a1 | 741 | static |
ab65b890 LJ |
742 | unsigned long _uatomic_xchg_monotonic_increase(unsigned long *ptr, |
743 | unsigned long v) | |
abc490a1 MD |
744 | { |
745 | unsigned long old1, old2; | |
746 | ||
747 | old1 = uatomic_read(ptr); | |
748 | do { | |
749 | old2 = old1; | |
750 | if (old2 >= v) | |
f9830efd | 751 | return old2; |
abc490a1 | 752 | } while ((old1 = uatomic_cmpxchg(ptr, old2, v)) != old2); |
ab65b890 | 753 | return old2; |
abc490a1 MD |
754 | } |
755 | ||
48f1b16d LJ |
756 | static |
757 | void cds_lfht_alloc_bucket_table(struct cds_lfht *ht, unsigned long order) | |
758 | { | |
759 | if (order == 0) { | |
760 | ht->t.tbl[0] = calloc(ht->min_alloc_size, | |
761 | sizeof(struct cds_lfht_node)); | |
762 | assert(ht->t.tbl[0]); | |
763 | } else if (order > ht->min_alloc_order) { | |
764 | ht->t.tbl[order] = calloc(1UL << (order -1), | |
765 | sizeof(struct cds_lfht_node)); | |
766 | assert(ht->t.tbl[order]); | |
767 | } | |
768 | /* Nothing to do for 0 < order && order <= ht->min_alloc_order */ | |
769 | } | |
770 | ||
771 | /* | |
772 | * cds_lfht_free_bucket_table() should be called with decreasing order. | |
773 | * When cds_lfht_free_bucket_table(0) is called, it means the whole | |
774 | * lfht is destroyed. | |
775 | */ | |
776 | static | |
777 | void cds_lfht_free_bucket_table(struct cds_lfht *ht, unsigned long order) | |
778 | { | |
779 | if (order == 0) | |
780 | poison_free(ht->t.tbl[0]); | |
781 | else if (order > ht->min_alloc_order) | |
782 | poison_free(ht->t.tbl[order]); | |
783 | /* Nothing to do for 0 < order && order <= ht->min_alloc_order */ | |
784 | } | |
785 | ||
9d72a73f LJ |
786 | static inline |
787 | struct cds_lfht_node *bucket_at(struct cds_lfht *ht, unsigned long index) | |
f4a9cc0b | 788 | { |
9d72a73f | 789 | unsigned long order; |
ef6e6171 | 790 | |
9d72a73f LJ |
791 | if ((__builtin_constant_p(index) && index == 0) |
792 | || index < ht->min_alloc_size) { | |
793 | dbg_printf("bucket index %lu order 0 aridx 0\n", index); | |
dcc26ef4 | 794 | return &ht->t.tbl[0][index]; |
ef6e6171 | 795 | } |
a4ea2223 LJ |
796 | /* |
797 | * equivalent to get_count_order_ulong(index + 1), but optimizes | |
798 | * away the non-existing 0 special-case for | |
799 | * get_count_order_ulong. | |
800 | */ | |
801 | order = fls_ulong(index); | |
9d72a73f LJ |
802 | dbg_printf("bucket index %lu order %lu aridx %lu\n", |
803 | index, order, index & ((1UL << (order - 1)) - 1)); | |
dcc26ef4 | 804 | return &ht->t.tbl[order][index & ((1UL << (order - 1)) - 1)]; |
f4a9cc0b LJ |
805 | } |
806 | ||
9d72a73f LJ |
807 | static inline |
808 | struct cds_lfht_node *lookup_bucket(struct cds_lfht *ht, unsigned long size, | |
809 | unsigned long hash) | |
810 | { | |
811 | assert(size > 0); | |
812 | return bucket_at(ht, hash & (size - 1)); | |
813 | } | |
814 | ||
273399de MD |
815 | /* |
816 | * Remove all logically deleted nodes from a bucket up to a certain node key. | |
817 | */ | |
818 | static | |
1ee8f000 | 819 | void _cds_lfht_gc_bucket(struct cds_lfht_node *bucket, struct cds_lfht_node *node) |
273399de | 820 | { |
14044b37 | 821 | struct cds_lfht_node *iter_prev, *iter, *next, *new_next; |
273399de | 822 | |
1ee8f000 LJ |
823 | assert(!is_bucket(bucket)); |
824 | assert(!is_removed(bucket)); | |
825 | assert(!is_bucket(node)); | |
c90201ac | 826 | assert(!is_removed(node)); |
273399de | 827 | for (;;) { |
1ee8f000 LJ |
828 | iter_prev = bucket; |
829 | /* We can always skip the bucket node initially */ | |
04db56f8 | 830 | iter = rcu_dereference(iter_prev->next); |
b4cb483f | 831 | assert(!is_removed(iter)); |
04db56f8 | 832 | assert(iter_prev->reverse_hash <= node->reverse_hash); |
bd4db153 | 833 | /* |
1ee8f000 | 834 | * We should never be called with bucket (start of chain) |
bd4db153 MD |
835 | * and logically removed node (end of path compression |
836 | * marker) being the actual same node. This would be a | |
837 | * bug in the algorithm implementation. | |
838 | */ | |
1ee8f000 | 839 | assert(bucket != node); |
273399de | 840 | for (;;) { |
8ed51e04 | 841 | if (caa_unlikely(is_end(iter))) |
f9c80341 | 842 | return; |
04db56f8 | 843 | if (caa_likely(clear_flag(iter)->reverse_hash > node->reverse_hash)) |
f9c80341 | 844 | return; |
04db56f8 | 845 | next = rcu_dereference(clear_flag(iter)->next); |
8ed51e04 | 846 | if (caa_likely(is_removed(next))) |
273399de | 847 | break; |
b453eae1 | 848 | iter_prev = clear_flag(iter); |
273399de MD |
849 | iter = next; |
850 | } | |
b198f0fd | 851 | assert(!is_removed(iter)); |
1ee8f000 LJ |
852 | if (is_bucket(iter)) |
853 | new_next = flag_bucket(clear_flag(next)); | |
f5596c94 MD |
854 | else |
855 | new_next = clear_flag(next); | |
04db56f8 | 856 | (void) uatomic_cmpxchg(&iter_prev->next, iter, new_next); |
273399de | 857 | } |
f9c80341 | 858 | return; |
273399de MD |
859 | } |
860 | ||
9357c415 MD |
861 | static |
862 | int _cds_lfht_replace(struct cds_lfht *ht, unsigned long size, | |
863 | struct cds_lfht_node *old_node, | |
3fb86f26 | 864 | struct cds_lfht_node *old_next, |
9357c415 MD |
865 | struct cds_lfht_node *new_node) |
866 | { | |
04db56f8 | 867 | struct cds_lfht_node *bucket, *ret_next; |
9357c415 MD |
868 | |
869 | if (!old_node) /* Return -ENOENT if asked to replace NULL node */ | |
7801dadd | 870 | return -ENOENT; |
9357c415 MD |
871 | |
872 | assert(!is_removed(old_node)); | |
1ee8f000 | 873 | assert(!is_bucket(old_node)); |
9357c415 | 874 | assert(!is_removed(new_node)); |
1ee8f000 | 875 | assert(!is_bucket(new_node)); |
9357c415 | 876 | assert(new_node != old_node); |
3fb86f26 | 877 | for (;;) { |
9357c415 | 878 | /* Insert after node to be replaced */ |
9357c415 MD |
879 | if (is_removed(old_next)) { |
880 | /* | |
881 | * Too late, the old node has been removed under us | |
882 | * between lookup and replace. Fail. | |
883 | */ | |
7801dadd | 884 | return -ENOENT; |
9357c415 | 885 | } |
1ee8f000 | 886 | assert(!is_bucket(old_next)); |
9357c415 | 887 | assert(new_node != clear_flag(old_next)); |
04db56f8 | 888 | new_node->next = clear_flag(old_next); |
9357c415 MD |
889 | /* |
890 | * Here is the whole trick for lock-free replace: we add | |
891 | * the replacement node _after_ the node we want to | |
892 | * replace by atomically setting its next pointer at the | |
893 | * same time we set its removal flag. Given that | |
894 | * the lookups/get next use an iterator aware of the | |
895 | * next pointer, they will either skip the old node due | |
896 | * to the removal flag and see the new node, or use | |
897 | * the old node, but will not see the new one. | |
898 | */ | |
04db56f8 | 899 | ret_next = uatomic_cmpxchg(&old_node->next, |
9357c415 | 900 | old_next, flag_removed(new_node)); |
3fb86f26 | 901 | if (ret_next == old_next) |
7801dadd | 902 | break; /* We performed the replacement. */ |
3fb86f26 LJ |
903 | old_next = ret_next; |
904 | } | |
9357c415 | 905 | |
9357c415 MD |
906 | /* |
907 | * Ensure that the old node is not visible to readers anymore: | |
908 | * lookup for the node, and remove it (along with any other | |
909 | * logically removed node) if found. | |
910 | */ | |
04db56f8 LJ |
911 | bucket = lookup_bucket(ht, size, bit_reverse_ulong(old_node->reverse_hash)); |
912 | _cds_lfht_gc_bucket(bucket, new_node); | |
7801dadd | 913 | |
04db56f8 | 914 | assert(is_removed(rcu_dereference(old_node->next))); |
7801dadd | 915 | return 0; |
9357c415 MD |
916 | } |
917 | ||
83beee94 MD |
918 | /* |
919 | * A non-NULL unique_ret pointer uses the "add unique" (or uniquify) add | |
920 | * mode. A NULL unique_ret allows creation of duplicate keys. | |
921 | */ | |
abc490a1 | 922 | static |
83beee94 | 923 | void _cds_lfht_add(struct cds_lfht *ht, |
0422d92c | 924 | cds_lfht_match_fct match, |
996ff57c | 925 | const void *key, |
83beee94 MD |
926 | unsigned long size, |
927 | struct cds_lfht_node *node, | |
928 | struct cds_lfht_iter *unique_ret, | |
1ee8f000 | 929 | int bucket_flag) |
abc490a1 | 930 | { |
14044b37 | 931 | struct cds_lfht_node *iter_prev, *iter, *next, *new_node, *new_next, |
960c9e4f | 932 | *return_node; |
04db56f8 | 933 | struct cds_lfht_node *bucket; |
abc490a1 | 934 | |
1ee8f000 | 935 | assert(!is_bucket(node)); |
c90201ac | 936 | assert(!is_removed(node)); |
04db56f8 | 937 | bucket = lookup_bucket(ht, size, bit_reverse_ulong(node->reverse_hash)); |
abc490a1 | 938 | for (;;) { |
adc0de68 | 939 | uint32_t chain_len = 0; |
abc490a1 | 940 | |
11519af6 MD |
941 | /* |
942 | * iter_prev points to the non-removed node prior to the | |
943 | * insert location. | |
11519af6 | 944 | */ |
04db56f8 | 945 | iter_prev = bucket; |
1ee8f000 | 946 | /* We can always skip the bucket node initially */ |
04db56f8 LJ |
947 | iter = rcu_dereference(iter_prev->next); |
948 | assert(iter_prev->reverse_hash <= node->reverse_hash); | |
abc490a1 | 949 | for (;;) { |
8ed51e04 | 950 | if (caa_unlikely(is_end(iter))) |
273399de | 951 | goto insert; |
04db56f8 | 952 | if (caa_likely(clear_flag(iter)->reverse_hash > node->reverse_hash)) |
273399de | 953 | goto insert; |
238cc06e | 954 | |
1ee8f000 LJ |
955 | /* bucket node is the first node of the identical-hash-value chain */ |
956 | if (bucket_flag && clear_flag(iter)->reverse_hash == node->reverse_hash) | |
194fdbd1 | 957 | goto insert; |
238cc06e | 958 | |
04db56f8 | 959 | next = rcu_dereference(clear_flag(iter)->next); |
8ed51e04 | 960 | if (caa_unlikely(is_removed(next))) |
9dba85be | 961 | goto gc_node; |
238cc06e LJ |
962 | |
963 | /* uniquely add */ | |
83beee94 | 964 | if (unique_ret |
1ee8f000 | 965 | && !is_bucket(next) |
04db56f8 | 966 | && clear_flag(iter)->reverse_hash == node->reverse_hash) { |
238cc06e LJ |
967 | struct cds_lfht_iter d_iter = { .node = node, .next = iter, }; |
968 | ||
969 | /* | |
970 | * uniquely adding inserts the node as the first | |
971 | * node of the identical-hash-value node chain. | |
972 | * | |
973 | * This semantic ensures no duplicated keys | |
974 | * should ever be observable in the table | |
975 | * (including observe one node by one node | |
976 | * by forward iterations) | |
977 | */ | |
04db56f8 | 978 | cds_lfht_next_duplicate(ht, match, key, &d_iter); |
238cc06e LJ |
979 | if (!d_iter.node) |
980 | goto insert; | |
981 | ||
982 | *unique_ret = d_iter; | |
83beee94 | 983 | return; |
48ed1c18 | 984 | } |
238cc06e | 985 | |
11519af6 | 986 | /* Only account for identical reverse hash once */ |
04db56f8 | 987 | if (iter_prev->reverse_hash != clear_flag(iter)->reverse_hash |
1ee8f000 | 988 | && !is_bucket(next)) |
4105056a | 989 | check_resize(ht, size, ++chain_len); |
11519af6 | 990 | iter_prev = clear_flag(iter); |
273399de | 991 | iter = next; |
abc490a1 | 992 | } |
48ed1c18 | 993 | |
273399de | 994 | insert: |
7ec59d3b | 995 | assert(node != clear_flag(iter)); |
11519af6 | 996 | assert(!is_removed(iter_prev)); |
c90201ac | 997 | assert(!is_removed(iter)); |
f000907d | 998 | assert(iter_prev != node); |
1ee8f000 | 999 | if (!bucket_flag) |
04db56f8 | 1000 | node->next = clear_flag(iter); |
f9c80341 | 1001 | else |
1ee8f000 LJ |
1002 | node->next = flag_bucket(clear_flag(iter)); |
1003 | if (is_bucket(iter)) | |
1004 | new_node = flag_bucket(node); | |
f5596c94 MD |
1005 | else |
1006 | new_node = node; | |
04db56f8 | 1007 | if (uatomic_cmpxchg(&iter_prev->next, iter, |
48ed1c18 | 1008 | new_node) != iter) { |
273399de | 1009 | continue; /* retry */ |
48ed1c18 | 1010 | } else { |
83beee94 | 1011 | return_node = node; |
960c9e4f | 1012 | goto end; |
48ed1c18 MD |
1013 | } |
1014 | ||
9dba85be MD |
1015 | gc_node: |
1016 | assert(!is_removed(iter)); | |
1ee8f000 LJ |
1017 | if (is_bucket(iter)) |
1018 | new_next = flag_bucket(clear_flag(next)); | |
f5596c94 MD |
1019 | else |
1020 | new_next = clear_flag(next); | |
04db56f8 | 1021 | (void) uatomic_cmpxchg(&iter_prev->next, iter, new_next); |
273399de | 1022 | /* retry */ |
464a1ec9 | 1023 | } |
9357c415 | 1024 | end: |
83beee94 MD |
1025 | if (unique_ret) { |
1026 | unique_ret->node = return_node; | |
1027 | /* unique_ret->next left unset, never used. */ | |
1028 | } | |
abc490a1 | 1029 | } |
464a1ec9 | 1030 | |
abc490a1 | 1031 | static |
860d07e8 | 1032 | int _cds_lfht_del(struct cds_lfht *ht, unsigned long size, |
4105056a | 1033 | struct cds_lfht_node *node, |
1ee8f000 | 1034 | int bucket_removal) |
abc490a1 | 1035 | { |
04db56f8 | 1036 | struct cds_lfht_node *bucket, *next, *old; |
5e28c532 | 1037 | |
9357c415 | 1038 | if (!node) /* Return -ENOENT if asked to delete NULL node */ |
743f9143 | 1039 | return -ENOENT; |
9357c415 | 1040 | |
7ec59d3b | 1041 | /* logically delete the node */ |
1ee8f000 | 1042 | assert(!is_bucket(node)); |
c90201ac | 1043 | assert(!is_removed(node)); |
04db56f8 | 1044 | old = rcu_dereference(node->next); |
7ec59d3b | 1045 | do { |
48ed1c18 MD |
1046 | struct cds_lfht_node *new_next; |
1047 | ||
7ec59d3b | 1048 | next = old; |
8ed51e04 | 1049 | if (caa_unlikely(is_removed(next))) |
743f9143 | 1050 | return -ENOENT; |
1ee8f000 LJ |
1051 | if (bucket_removal) |
1052 | assert(is_bucket(next)); | |
1475579c | 1053 | else |
1ee8f000 | 1054 | assert(!is_bucket(next)); |
48ed1c18 | 1055 | new_next = flag_removed(next); |
04db56f8 | 1056 | old = uatomic_cmpxchg(&node->next, next, new_next); |
7ec59d3b | 1057 | } while (old != next); |
7ec59d3b | 1058 | /* We performed the (logical) deletion. */ |
7ec59d3b MD |
1059 | |
1060 | /* | |
1061 | * Ensure that the node is not visible to readers anymore: lookup for | |
273399de MD |
1062 | * the node, and remove it (along with any other logically removed node) |
1063 | * if found. | |
11519af6 | 1064 | */ |
04db56f8 LJ |
1065 | bucket = lookup_bucket(ht, size, bit_reverse_ulong(node->reverse_hash)); |
1066 | _cds_lfht_gc_bucket(bucket, node); | |
743f9143 | 1067 | |
04db56f8 | 1068 | assert(is_removed(rcu_dereference(node->next))); |
743f9143 | 1069 | return 0; |
abc490a1 | 1070 | } |
2ed95849 | 1071 | |
b7d619b0 MD |
1072 | static |
1073 | void *partition_resize_thread(void *arg) | |
1074 | { | |
1075 | struct partition_resize_work *work = arg; | |
1076 | ||
1077 | work->ht->cds_lfht_rcu_register_thread(); | |
1078 | work->fct(work->ht, work->i, work->start, work->len); | |
1079 | work->ht->cds_lfht_rcu_unregister_thread(); | |
1080 | return NULL; | |
1081 | } | |
1082 | ||
1083 | static | |
1084 | void partition_resize_helper(struct cds_lfht *ht, unsigned long i, | |
1085 | unsigned long len, | |
1086 | void (*fct)(struct cds_lfht *ht, unsigned long i, | |
1087 | unsigned long start, unsigned long len)) | |
1088 | { | |
1089 | unsigned long partition_len; | |
1090 | struct partition_resize_work *work; | |
6083a889 MD |
1091 | int thread, ret; |
1092 | unsigned long nr_threads; | |
b7d619b0 | 1093 | |
6083a889 MD |
1094 | /* |
1095 | * Note: nr_cpus_mask + 1 is always power of 2. | |
1096 | * We spawn just the number of threads we need to satisfy the minimum | |
1097 | * partition size, up to the number of CPUs in the system. | |
1098 | */ | |
91452a6a MD |
1099 | if (nr_cpus_mask > 0) { |
1100 | nr_threads = min(nr_cpus_mask + 1, | |
1101 | len >> MIN_PARTITION_PER_THREAD_ORDER); | |
1102 | } else { | |
1103 | nr_threads = 1; | |
1104 | } | |
6083a889 MD |
1105 | partition_len = len >> get_count_order_ulong(nr_threads); |
1106 | work = calloc(nr_threads, sizeof(*work)); | |
b7d619b0 | 1107 | assert(work); |
6083a889 MD |
1108 | for (thread = 0; thread < nr_threads; thread++) { |
1109 | work[thread].ht = ht; | |
1110 | work[thread].i = i; | |
1111 | work[thread].len = partition_len; | |
1112 | work[thread].start = thread * partition_len; | |
1113 | work[thread].fct = fct; | |
1af6e26e | 1114 | ret = pthread_create(&(work[thread].thread_id), ht->resize_attr, |
6083a889 | 1115 | partition_resize_thread, &work[thread]); |
b7d619b0 MD |
1116 | assert(!ret); |
1117 | } | |
6083a889 | 1118 | for (thread = 0; thread < nr_threads; thread++) { |
1af6e26e | 1119 | ret = pthread_join(work[thread].thread_id, NULL); |
b7d619b0 MD |
1120 | assert(!ret); |
1121 | } | |
1122 | free(work); | |
b7d619b0 MD |
1123 | } |
1124 | ||
e8de508e MD |
1125 | /* |
1126 | * Holding RCU read lock to protect _cds_lfht_add against memory | |
1127 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
1128 | * problem). | |
9ee0fc9a | 1129 | * |
b7d619b0 | 1130 | * When we reach a certain length, we can split this population phase over |
9ee0fc9a MD |
1131 | * many worker threads, based on the number of CPUs available in the system. |
1132 | * This should therefore take care of not having the expand lagging behind too | |
1133 | * many concurrent insertion threads by using the scheduler's ability to | |
1ee8f000 | 1134 | * schedule bucket node population fairly with insertions. |
e8de508e | 1135 | */ |
4105056a | 1136 | static |
b7d619b0 MD |
1137 | void init_table_populate_partition(struct cds_lfht *ht, unsigned long i, |
1138 | unsigned long start, unsigned long len) | |
4105056a | 1139 | { |
9d72a73f | 1140 | unsigned long j, size = 1UL << (i - 1); |
4105056a | 1141 | |
d0d8f9aa | 1142 | assert(i > MIN_TABLE_ORDER); |
4105056a | 1143 | ht->cds_lfht_rcu_read_lock(); |
9d72a73f LJ |
1144 | for (j = size + start; j < size + start + len; j++) { |
1145 | struct cds_lfht_node *new_node = bucket_at(ht, j); | |
1146 | ||
1147 | assert(j >= size && j < (size << 1)); | |
1148 | dbg_printf("init populate: order %lu index %lu hash %lu\n", | |
1149 | i, j, j); | |
1150 | new_node->reverse_hash = bit_reverse_ulong(j); | |
1151 | _cds_lfht_add(ht, NULL, NULL, size, new_node, NULL, 1); | |
4105056a MD |
1152 | } |
1153 | ht->cds_lfht_rcu_read_unlock(); | |
b7d619b0 MD |
1154 | } |
1155 | ||
1156 | static | |
1157 | void init_table_populate(struct cds_lfht *ht, unsigned long i, | |
1158 | unsigned long len) | |
1159 | { | |
1160 | assert(nr_cpus_mask != -1); | |
6083a889 | 1161 | if (nr_cpus_mask < 0 || len < 2 * MIN_PARTITION_PER_THREAD) { |
b7d619b0 MD |
1162 | ht->cds_lfht_rcu_thread_online(); |
1163 | init_table_populate_partition(ht, i, 0, len); | |
1164 | ht->cds_lfht_rcu_thread_offline(); | |
1165 | return; | |
1166 | } | |
1167 | partition_resize_helper(ht, i, len, init_table_populate_partition); | |
4105056a MD |
1168 | } |
1169 | ||
abc490a1 | 1170 | static |
4105056a | 1171 | void init_table(struct cds_lfht *ht, |
93d46c39 | 1172 | unsigned long first_order, unsigned long last_order) |
24365af7 | 1173 | { |
93d46c39 | 1174 | unsigned long i; |
24365af7 | 1175 | |
93d46c39 LJ |
1176 | dbg_printf("init table: first_order %lu last_order %lu\n", |
1177 | first_order, last_order); | |
d0d8f9aa | 1178 | assert(first_order > MIN_TABLE_ORDER); |
93d46c39 | 1179 | for (i = first_order; i <= last_order; i++) { |
4105056a | 1180 | unsigned long len; |
24365af7 | 1181 | |
4f6e90b7 | 1182 | len = 1UL << (i - 1); |
f0c29ed7 | 1183 | dbg_printf("init order %lu len: %lu\n", i, len); |
4d676753 MD |
1184 | |
1185 | /* Stop expand if the resize target changes under us */ | |
4f6e90b7 | 1186 | if (CMM_LOAD_SHARED(ht->t.resize_target) < (1UL << i)) |
4d676753 MD |
1187 | break; |
1188 | ||
48f1b16d | 1189 | cds_lfht_alloc_bucket_table(ht, i); |
4105056a | 1190 | |
4105056a | 1191 | /* |
1ee8f000 LJ |
1192 | * Set all bucket nodes reverse hash values for a level and |
1193 | * link all bucket nodes into the table. | |
4105056a | 1194 | */ |
dc1da8f6 | 1195 | init_table_populate(ht, i, len); |
4105056a | 1196 | |
f9c80341 MD |
1197 | /* |
1198 | * Update table size. | |
1199 | */ | |
1200 | cmm_smp_wmb(); /* populate data before RCU size */ | |
4f6e90b7 | 1201 | CMM_STORE_SHARED(ht->t.size, 1UL << i); |
f9c80341 | 1202 | |
4f6e90b7 | 1203 | dbg_printf("init new size: %lu\n", 1UL << i); |
4105056a MD |
1204 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
1205 | break; | |
1206 | } | |
1207 | } | |
1208 | ||
e8de508e MD |
1209 | /* |
1210 | * Holding RCU read lock to protect _cds_lfht_remove against memory | |
1211 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
1212 | * problem). | |
1213 | * For a single level, we logically remove and garbage collect each node. | |
1214 | * | |
1215 | * As a design choice, we perform logical removal and garbage collection on a | |
1216 | * node-per-node basis to simplify this algorithm. We also assume keeping good | |
1217 | * cache locality of the operation would overweight possible performance gain | |
1218 | * that could be achieved by batching garbage collection for multiple levels. | |
1219 | * However, this would have to be justified by benchmarks. | |
1220 | * | |
1221 | * Concurrent removal and add operations are helping us perform garbage | |
1222 | * collection of logically removed nodes. We guarantee that all logically | |
1223 | * removed nodes have been garbage-collected (unlinked) before call_rcu is | |
1ee8f000 | 1224 | * invoked to free a hole level of bucket nodes (after a grace period). |
e8de508e MD |
1225 | * |
1226 | * Logical removal and garbage collection can therefore be done in batch or on a | |
1227 | * node-per-node basis, as long as the guarantee above holds. | |
9ee0fc9a | 1228 | * |
b7d619b0 MD |
1229 | * When we reach a certain length, we can split this removal over many worker |
1230 | * threads, based on the number of CPUs available in the system. This should | |
1231 | * take care of not letting resize process lag behind too many concurrent | |
9ee0fc9a | 1232 | * updater threads actively inserting into the hash table. |
e8de508e | 1233 | */ |
4105056a | 1234 | static |
b7d619b0 MD |
1235 | void remove_table_partition(struct cds_lfht *ht, unsigned long i, |
1236 | unsigned long start, unsigned long len) | |
4105056a | 1237 | { |
9d72a73f | 1238 | unsigned long j, size = 1UL << (i - 1); |
4105056a | 1239 | |
d0d8f9aa | 1240 | assert(i > MIN_TABLE_ORDER); |
4105056a | 1241 | ht->cds_lfht_rcu_read_lock(); |
9d72a73f LJ |
1242 | for (j = size + start; j < size + start + len; j++) { |
1243 | struct cds_lfht_node *fini_node = bucket_at(ht, j); | |
1244 | ||
1245 | assert(j >= size && j < (size << 1)); | |
1246 | dbg_printf("remove entry: order %lu index %lu hash %lu\n", | |
1247 | i, j, j); | |
1248 | fini_node->reverse_hash = bit_reverse_ulong(j); | |
1249 | (void) _cds_lfht_del(ht, size, fini_node, 1); | |
abc490a1 | 1250 | } |
4105056a | 1251 | ht->cds_lfht_rcu_read_unlock(); |
b7d619b0 MD |
1252 | } |
1253 | ||
1254 | static | |
1255 | void remove_table(struct cds_lfht *ht, unsigned long i, unsigned long len) | |
1256 | { | |
1257 | ||
1258 | assert(nr_cpus_mask != -1); | |
6083a889 | 1259 | if (nr_cpus_mask < 0 || len < 2 * MIN_PARTITION_PER_THREAD) { |
b7d619b0 MD |
1260 | ht->cds_lfht_rcu_thread_online(); |
1261 | remove_table_partition(ht, i, 0, len); | |
1262 | ht->cds_lfht_rcu_thread_offline(); | |
1263 | return; | |
1264 | } | |
1265 | partition_resize_helper(ht, i, len, remove_table_partition); | |
2ed95849 MD |
1266 | } |
1267 | ||
1475579c | 1268 | static |
4105056a | 1269 | void fini_table(struct cds_lfht *ht, |
93d46c39 | 1270 | unsigned long first_order, unsigned long last_order) |
1475579c | 1271 | { |
93d46c39 | 1272 | long i; |
48f1b16d | 1273 | unsigned long free_by_rcu_order = 0; |
1475579c | 1274 | |
93d46c39 LJ |
1275 | dbg_printf("fini table: first_order %lu last_order %lu\n", |
1276 | first_order, last_order); | |
d0d8f9aa | 1277 | assert(first_order > MIN_TABLE_ORDER); |
93d46c39 | 1278 | for (i = last_order; i >= first_order; i--) { |
4105056a | 1279 | unsigned long len; |
1475579c | 1280 | |
4f6e90b7 | 1281 | len = 1UL << (i - 1); |
1475579c | 1282 | dbg_printf("fini order %lu len: %lu\n", i, len); |
4105056a | 1283 | |
4d676753 MD |
1284 | /* Stop shrink if the resize target changes under us */ |
1285 | if (CMM_LOAD_SHARED(ht->t.resize_target) > (1UL << (i - 1))) | |
1286 | break; | |
1287 | ||
1288 | cmm_smp_wmb(); /* populate data before RCU size */ | |
1289 | CMM_STORE_SHARED(ht->t.size, 1UL << (i - 1)); | |
1290 | ||
1291 | /* | |
1292 | * We need to wait for all add operations to reach Q.S. (and | |
1293 | * thus use the new table for lookups) before we can start | |
1ee8f000 | 1294 | * releasing the old bucket nodes. Otherwise their lookup will |
4d676753 MD |
1295 | * return a logically removed node as insert position. |
1296 | */ | |
1297 | ht->cds_lfht_synchronize_rcu(); | |
48f1b16d LJ |
1298 | if (free_by_rcu_order) |
1299 | cds_lfht_free_bucket_table(ht, free_by_rcu_order); | |
4d676753 | 1300 | |
21263e21 | 1301 | /* |
1ee8f000 LJ |
1302 | * Set "removed" flag in bucket nodes about to be removed. |
1303 | * Unlink all now-logically-removed bucket node pointers. | |
4105056a MD |
1304 | * Concurrent add/remove operation are helping us doing |
1305 | * the gc. | |
21263e21 | 1306 | */ |
4105056a MD |
1307 | remove_table(ht, i, len); |
1308 | ||
48f1b16d | 1309 | free_by_rcu_order = i; |
4105056a MD |
1310 | |
1311 | dbg_printf("fini new size: %lu\n", 1UL << i); | |
1475579c MD |
1312 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
1313 | break; | |
1314 | } | |
0d14ceb2 | 1315 | |
48f1b16d | 1316 | if (free_by_rcu_order) { |
0d14ceb2 | 1317 | ht->cds_lfht_synchronize_rcu(); |
48f1b16d | 1318 | cds_lfht_free_bucket_table(ht, free_by_rcu_order); |
0d14ceb2 | 1319 | } |
1475579c MD |
1320 | } |
1321 | ||
ff0d69de | 1322 | static |
1ee8f000 | 1323 | void cds_lfht_create_bucket(struct cds_lfht *ht, unsigned long size) |
ff0d69de | 1324 | { |
04db56f8 | 1325 | struct cds_lfht_node *prev, *node; |
9d72a73f | 1326 | unsigned long order, len, i; |
ff0d69de | 1327 | |
48f1b16d | 1328 | cds_lfht_alloc_bucket_table(ht, 0); |
ff0d69de | 1329 | |
9d72a73f LJ |
1330 | dbg_printf("create bucket: order 0 index 0 hash 0\n"); |
1331 | node = bucket_at(ht, 0); | |
1332 | node->next = flag_bucket(get_end()); | |
1333 | node->reverse_hash = 0; | |
ff0d69de LJ |
1334 | |
1335 | for (order = 1; order < get_count_order_ulong(size) + 1; order++) { | |
1336 | len = 1UL << (order - 1); | |
48f1b16d | 1337 | cds_lfht_alloc_bucket_table(ht, order); |
ff0d69de | 1338 | |
9d72a73f LJ |
1339 | for (i = 0; i < len; i++) { |
1340 | /* | |
1341 | * Now, we are trying to init the node with the | |
1342 | * hash=(len+i) (which is also a bucket with the | |
1343 | * index=(len+i)) and insert it into the hash table, | |
1344 | * so this node has to be inserted after the bucket | |
1345 | * with the index=(len+i)&(len-1)=i. And because there | |
1346 | * is no other non-bucket node nor bucket node with | |
1347 | * larger index/hash inserted, so the bucket node | |
1348 | * being inserted should be inserted directly linked | |
1349 | * after the bucket node with index=i. | |
1350 | */ | |
1351 | prev = bucket_at(ht, i); | |
1352 | node = bucket_at(ht, len + i); | |
ff0d69de | 1353 | |
1ee8f000 | 1354 | dbg_printf("create bucket: order %lu index %lu hash %lu\n", |
9d72a73f LJ |
1355 | order, len + i, len + i); |
1356 | node->reverse_hash = bit_reverse_ulong(len + i); | |
1357 | ||
1358 | /* insert after prev */ | |
1359 | assert(is_bucket(prev->next)); | |
ff0d69de | 1360 | node->next = prev->next; |
1ee8f000 | 1361 | prev->next = flag_bucket(node); |
ff0d69de LJ |
1362 | } |
1363 | } | |
1364 | } | |
1365 | ||
0422d92c | 1366 | struct cds_lfht *_cds_lfht_new(unsigned long init_size, |
5488222b | 1367 | unsigned long min_alloc_size, |
b8af5011 | 1368 | int flags, |
14044b37 | 1369 | void (*cds_lfht_call_rcu)(struct rcu_head *head, |
1475579c | 1370 | void (*func)(struct rcu_head *head)), |
01dbfa62 MD |
1371 | void (*cds_lfht_synchronize_rcu)(void), |
1372 | void (*cds_lfht_rcu_read_lock)(void), | |
5f511391 MD |
1373 | void (*cds_lfht_rcu_read_unlock)(void), |
1374 | void (*cds_lfht_rcu_thread_offline)(void), | |
b7d619b0 MD |
1375 | void (*cds_lfht_rcu_thread_online)(void), |
1376 | void (*cds_lfht_rcu_register_thread)(void), | |
1377 | void (*cds_lfht_rcu_unregister_thread)(void), | |
1378 | pthread_attr_t *attr) | |
abc490a1 | 1379 | { |
14044b37 | 1380 | struct cds_lfht *ht; |
24365af7 | 1381 | unsigned long order; |
abc490a1 | 1382 | |
5488222b LJ |
1383 | /* min_alloc_size must be power of two */ |
1384 | if (!min_alloc_size || (min_alloc_size & (min_alloc_size - 1))) | |
1385 | return NULL; | |
8129be4e | 1386 | /* init_size must be power of two */ |
5488222b | 1387 | if (!init_size || (init_size & (init_size - 1))) |
8129be4e | 1388 | return NULL; |
5488222b | 1389 | min_alloc_size = max(min_alloc_size, MIN_TABLE_SIZE); |
d0d8f9aa | 1390 | init_size = max(init_size, MIN_TABLE_SIZE); |
14044b37 | 1391 | ht = calloc(1, sizeof(struct cds_lfht)); |
b7d619b0 | 1392 | assert(ht); |
b5d6b20f | 1393 | ht->flags = flags; |
14044b37 | 1394 | ht->cds_lfht_call_rcu = cds_lfht_call_rcu; |
1475579c | 1395 | ht->cds_lfht_synchronize_rcu = cds_lfht_synchronize_rcu; |
01dbfa62 MD |
1396 | ht->cds_lfht_rcu_read_lock = cds_lfht_rcu_read_lock; |
1397 | ht->cds_lfht_rcu_read_unlock = cds_lfht_rcu_read_unlock; | |
5f511391 MD |
1398 | ht->cds_lfht_rcu_thread_offline = cds_lfht_rcu_thread_offline; |
1399 | ht->cds_lfht_rcu_thread_online = cds_lfht_rcu_thread_online; | |
b7d619b0 MD |
1400 | ht->cds_lfht_rcu_register_thread = cds_lfht_rcu_register_thread; |
1401 | ht->cds_lfht_rcu_unregister_thread = cds_lfht_rcu_unregister_thread; | |
1402 | ht->resize_attr = attr; | |
5afadd12 | 1403 | alloc_split_items_count(ht); |
abc490a1 MD |
1404 | /* this mutex should not nest in read-side C.S. */ |
1405 | pthread_mutex_init(&ht->resize_mutex, NULL); | |
5488222b | 1406 | order = get_count_order_ulong(init_size); |
93d46c39 | 1407 | ht->t.resize_target = 1UL << order; |
5488222b LJ |
1408 | ht->min_alloc_size = min_alloc_size; |
1409 | ht->min_alloc_order = get_count_order_ulong(min_alloc_size); | |
1ee8f000 | 1410 | cds_lfht_create_bucket(ht, 1UL << order); |
bcbd36fc | 1411 | ht->t.size = 1UL << order; |
abc490a1 MD |
1412 | return ht; |
1413 | } | |
1414 | ||
6f554439 | 1415 | void cds_lfht_lookup(struct cds_lfht *ht, unsigned long hash, |
996ff57c | 1416 | cds_lfht_match_fct match, const void *key, |
6f554439 | 1417 | struct cds_lfht_iter *iter) |
2ed95849 | 1418 | { |
04db56f8 | 1419 | struct cds_lfht_node *node, *next, *bucket; |
0422d92c | 1420 | unsigned long reverse_hash, size; |
2ed95849 | 1421 | |
abc490a1 | 1422 | reverse_hash = bit_reverse_ulong(hash); |
464a1ec9 | 1423 | |
4105056a | 1424 | size = rcu_dereference(ht->t.size); |
04db56f8 | 1425 | bucket = lookup_bucket(ht, size, hash); |
1ee8f000 | 1426 | /* We can always skip the bucket node initially */ |
04db56f8 | 1427 | node = rcu_dereference(bucket->next); |
bb7b2f26 | 1428 | node = clear_flag(node); |
2ed95849 | 1429 | for (;;) { |
8ed51e04 | 1430 | if (caa_unlikely(is_end(node))) { |
96ad1112 | 1431 | node = next = NULL; |
abc490a1 | 1432 | break; |
bb7b2f26 | 1433 | } |
04db56f8 | 1434 | if (caa_unlikely(node->reverse_hash > reverse_hash)) { |
96ad1112 | 1435 | node = next = NULL; |
abc490a1 | 1436 | break; |
2ed95849 | 1437 | } |
04db56f8 | 1438 | next = rcu_dereference(node->next); |
7f52427b | 1439 | assert(node == clear_flag(node)); |
8ed51e04 | 1440 | if (caa_likely(!is_removed(next)) |
1ee8f000 | 1441 | && !is_bucket(next) |
04db56f8 | 1442 | && node->reverse_hash == reverse_hash |
0422d92c | 1443 | && caa_likely(match(node, key))) { |
273399de | 1444 | break; |
2ed95849 | 1445 | } |
1b81fe1a | 1446 | node = clear_flag(next); |
2ed95849 | 1447 | } |
1ee8f000 | 1448 | assert(!node || !is_bucket(rcu_dereference(node->next))); |
adc0de68 MD |
1449 | iter->node = node; |
1450 | iter->next = next; | |
abc490a1 | 1451 | } |
e0ba718a | 1452 | |
0422d92c | 1453 | void cds_lfht_next_duplicate(struct cds_lfht *ht, cds_lfht_match_fct match, |
996ff57c | 1454 | const void *key, struct cds_lfht_iter *iter) |
a481e5ff | 1455 | { |
adc0de68 | 1456 | struct cds_lfht_node *node, *next; |
a481e5ff | 1457 | unsigned long reverse_hash; |
a481e5ff | 1458 | |
adc0de68 | 1459 | node = iter->node; |
04db56f8 | 1460 | reverse_hash = node->reverse_hash; |
adc0de68 | 1461 | next = iter->next; |
a481e5ff MD |
1462 | node = clear_flag(next); |
1463 | ||
1464 | for (;;) { | |
8ed51e04 | 1465 | if (caa_unlikely(is_end(node))) { |
96ad1112 | 1466 | node = next = NULL; |
a481e5ff | 1467 | break; |
bb7b2f26 | 1468 | } |
04db56f8 | 1469 | if (caa_unlikely(node->reverse_hash > reverse_hash)) { |
96ad1112 | 1470 | node = next = NULL; |
a481e5ff MD |
1471 | break; |
1472 | } | |
04db56f8 | 1473 | next = rcu_dereference(node->next); |
8ed51e04 | 1474 | if (caa_likely(!is_removed(next)) |
1ee8f000 | 1475 | && !is_bucket(next) |
04db56f8 | 1476 | && caa_likely(match(node, key))) { |
a481e5ff MD |
1477 | break; |
1478 | } | |
1479 | node = clear_flag(next); | |
1480 | } | |
1ee8f000 | 1481 | assert(!node || !is_bucket(rcu_dereference(node->next))); |
adc0de68 MD |
1482 | iter->node = node; |
1483 | iter->next = next; | |
a481e5ff MD |
1484 | } |
1485 | ||
4e9b9fbf MD |
1486 | void cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_iter *iter) |
1487 | { | |
1488 | struct cds_lfht_node *node, *next; | |
1489 | ||
853395e1 | 1490 | node = clear_flag(iter->next); |
4e9b9fbf | 1491 | for (;;) { |
8ed51e04 | 1492 | if (caa_unlikely(is_end(node))) { |
4e9b9fbf MD |
1493 | node = next = NULL; |
1494 | break; | |
1495 | } | |
04db56f8 | 1496 | next = rcu_dereference(node->next); |
8ed51e04 | 1497 | if (caa_likely(!is_removed(next)) |
1ee8f000 | 1498 | && !is_bucket(next)) { |
4e9b9fbf MD |
1499 | break; |
1500 | } | |
1501 | node = clear_flag(next); | |
1502 | } | |
1ee8f000 | 1503 | assert(!node || !is_bucket(rcu_dereference(node->next))); |
4e9b9fbf MD |
1504 | iter->node = node; |
1505 | iter->next = next; | |
1506 | } | |
1507 | ||
1508 | void cds_lfht_first(struct cds_lfht *ht, struct cds_lfht_iter *iter) | |
1509 | { | |
4e9b9fbf | 1510 | /* |
1ee8f000 | 1511 | * Get next after first bucket node. The first bucket node is the |
4e9b9fbf MD |
1512 | * first node of the linked list. |
1513 | */ | |
9d72a73f | 1514 | iter->next = bucket_at(ht, 0)->next; |
4e9b9fbf MD |
1515 | cds_lfht_next(ht, iter); |
1516 | } | |
1517 | ||
0422d92c MD |
1518 | void cds_lfht_add(struct cds_lfht *ht, unsigned long hash, |
1519 | struct cds_lfht_node *node) | |
abc490a1 | 1520 | { |
0422d92c | 1521 | unsigned long size; |
ab7d5fc6 | 1522 | |
04db56f8 | 1523 | node->reverse_hash = bit_reverse_ulong((unsigned long) hash); |
4105056a | 1524 | size = rcu_dereference(ht->t.size); |
04db56f8 | 1525 | _cds_lfht_add(ht, NULL, NULL, size, node, NULL, 0); |
14360f1c | 1526 | ht_count_add(ht, size, hash); |
3eca1b8c MD |
1527 | } |
1528 | ||
14044b37 | 1529 | struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, |
6f554439 | 1530 | unsigned long hash, |
0422d92c | 1531 | cds_lfht_match_fct match, |
996ff57c | 1532 | const void *key, |
48ed1c18 | 1533 | struct cds_lfht_node *node) |
3eca1b8c | 1534 | { |
0422d92c | 1535 | unsigned long size; |
83beee94 | 1536 | struct cds_lfht_iter iter; |
3eca1b8c | 1537 | |
04db56f8 | 1538 | node->reverse_hash = bit_reverse_ulong((unsigned long) hash); |
4105056a | 1539 | size = rcu_dereference(ht->t.size); |
04db56f8 | 1540 | _cds_lfht_add(ht, match, key, size, node, &iter, 0); |
83beee94 | 1541 | if (iter.node == node) |
14360f1c | 1542 | ht_count_add(ht, size, hash); |
83beee94 | 1543 | return iter.node; |
2ed95849 MD |
1544 | } |
1545 | ||
9357c415 | 1546 | struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht, |
6f554439 | 1547 | unsigned long hash, |
0422d92c | 1548 | cds_lfht_match_fct match, |
996ff57c | 1549 | const void *key, |
48ed1c18 MD |
1550 | struct cds_lfht_node *node) |
1551 | { | |
0422d92c | 1552 | unsigned long size; |
83beee94 | 1553 | struct cds_lfht_iter iter; |
48ed1c18 | 1554 | |
04db56f8 | 1555 | node->reverse_hash = bit_reverse_ulong((unsigned long) hash); |
48ed1c18 | 1556 | size = rcu_dereference(ht->t.size); |
83beee94 | 1557 | for (;;) { |
04db56f8 | 1558 | _cds_lfht_add(ht, match, key, size, node, &iter, 0); |
83beee94 | 1559 | if (iter.node == node) { |
14360f1c | 1560 | ht_count_add(ht, size, hash); |
83beee94 MD |
1561 | return NULL; |
1562 | } | |
1563 | ||
1564 | if (!_cds_lfht_replace(ht, size, iter.node, iter.next, node)) | |
1565 | return iter.node; | |
1566 | } | |
48ed1c18 MD |
1567 | } |
1568 | ||
9357c415 MD |
1569 | int cds_lfht_replace(struct cds_lfht *ht, struct cds_lfht_iter *old_iter, |
1570 | struct cds_lfht_node *new_node) | |
1571 | { | |
1572 | unsigned long size; | |
1573 | ||
1574 | size = rcu_dereference(ht->t.size); | |
1575 | return _cds_lfht_replace(ht, size, old_iter->node, old_iter->next, | |
1576 | new_node); | |
1577 | } | |
1578 | ||
1579 | int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_iter *iter) | |
2ed95849 | 1580 | { |
14360f1c | 1581 | unsigned long size, hash; |
df44348d | 1582 | int ret; |
abc490a1 | 1583 | |
4105056a | 1584 | size = rcu_dereference(ht->t.size); |
9357c415 | 1585 | ret = _cds_lfht_del(ht, size, iter->node, 0); |
14360f1c | 1586 | if (!ret) { |
04db56f8 | 1587 | hash = bit_reverse_ulong(iter->node->reverse_hash); |
14360f1c LJ |
1588 | ht_count_del(ht, size, hash); |
1589 | } | |
df44348d | 1590 | return ret; |
2ed95849 | 1591 | } |
ab7d5fc6 | 1592 | |
abc490a1 | 1593 | static |
1ee8f000 | 1594 | int cds_lfht_delete_bucket(struct cds_lfht *ht) |
674f7a69 | 1595 | { |
14044b37 | 1596 | struct cds_lfht_node *node; |
4105056a | 1597 | unsigned long order, i, size; |
674f7a69 | 1598 | |
abc490a1 | 1599 | /* Check that the table is empty */ |
9d72a73f | 1600 | node = bucket_at(ht, 0); |
abc490a1 | 1601 | do { |
04db56f8 | 1602 | node = clear_flag(node)->next; |
1ee8f000 | 1603 | if (!is_bucket(node)) |
abc490a1 | 1604 | return -EPERM; |
273399de | 1605 | assert(!is_removed(node)); |
bb7b2f26 | 1606 | } while (!is_end(node)); |
4105056a MD |
1607 | /* |
1608 | * size accessed without rcu_dereference because hash table is | |
1609 | * being destroyed. | |
1610 | */ | |
1611 | size = ht->t.size; | |
1ee8f000 | 1612 | /* Internal sanity check: all nodes left should be bucket */ |
48f1b16d LJ |
1613 | for (i = 0; i < size; i++) { |
1614 | node = bucket_at(ht, i); | |
1615 | dbg_printf("delete bucket: index %lu expected hash %lu hash %lu\n", | |
1616 | i, i, bit_reverse_ulong(node->reverse_hash)); | |
1617 | assert(is_bucket(node->next)); | |
1618 | } | |
24365af7 | 1619 | |
48f1b16d LJ |
1620 | for (order = get_count_order_ulong(size); (long)order >= 0; order--) |
1621 | cds_lfht_free_bucket_table(ht, order); | |
5488222b | 1622 | |
abc490a1 | 1623 | return 0; |
674f7a69 MD |
1624 | } |
1625 | ||
1626 | /* | |
1627 | * Should only be called when no more concurrent readers nor writers can | |
1628 | * possibly access the table. | |
1629 | */ | |
b7d619b0 | 1630 | int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr) |
674f7a69 | 1631 | { |
5e28c532 MD |
1632 | int ret; |
1633 | ||
848d4088 | 1634 | /* Wait for in-flight resize operations to complete */ |
24953e08 MD |
1635 | _CMM_STORE_SHARED(ht->in_progress_destroy, 1); |
1636 | cmm_smp_mb(); /* Store destroy before load resize */ | |
848d4088 MD |
1637 | while (uatomic_read(&ht->in_progress_resize)) |
1638 | poll(NULL, 0, 100); /* wait for 100ms */ | |
1ee8f000 | 1639 | ret = cds_lfht_delete_bucket(ht); |
abc490a1 MD |
1640 | if (ret) |
1641 | return ret; | |
5afadd12 | 1642 | free_split_items_count(ht); |
b7d619b0 MD |
1643 | if (attr) |
1644 | *attr = ht->resize_attr; | |
98808fb1 | 1645 | poison_free(ht); |
5e28c532 | 1646 | return ret; |
674f7a69 MD |
1647 | } |
1648 | ||
14044b37 | 1649 | void cds_lfht_count_nodes(struct cds_lfht *ht, |
d933dd0e | 1650 | long *approx_before, |
273399de | 1651 | unsigned long *count, |
973e5e1b | 1652 | unsigned long *removed, |
d933dd0e | 1653 | long *approx_after) |
273399de | 1654 | { |
14044b37 | 1655 | struct cds_lfht_node *node, *next; |
1ee8f000 | 1656 | unsigned long nr_bucket = 0; |
273399de | 1657 | |
7ed7682f | 1658 | *approx_before = 0; |
5afadd12 | 1659 | if (ht->split_count) { |
973e5e1b MD |
1660 | int i; |
1661 | ||
4c42f1b8 LJ |
1662 | for (i = 0; i < split_count_mask + 1; i++) { |
1663 | *approx_before += uatomic_read(&ht->split_count[i].add); | |
1664 | *approx_before -= uatomic_read(&ht->split_count[i].del); | |
973e5e1b MD |
1665 | } |
1666 | } | |
1667 | ||
273399de MD |
1668 | *count = 0; |
1669 | *removed = 0; | |
1670 | ||
1ee8f000 | 1671 | /* Count non-bucket nodes in the table */ |
9d72a73f | 1672 | node = bucket_at(ht, 0); |
273399de | 1673 | do { |
04db56f8 | 1674 | next = rcu_dereference(node->next); |
b198f0fd | 1675 | if (is_removed(next)) { |
1ee8f000 | 1676 | if (!is_bucket(next)) |
973e5e1b MD |
1677 | (*removed)++; |
1678 | else | |
1ee8f000 LJ |
1679 | (nr_bucket)++; |
1680 | } else if (!is_bucket(next)) | |
273399de | 1681 | (*count)++; |
24365af7 | 1682 | else |
1ee8f000 | 1683 | (nr_bucket)++; |
273399de | 1684 | node = clear_flag(next); |
bb7b2f26 | 1685 | } while (!is_end(node)); |
1ee8f000 | 1686 | dbg_printf("number of bucket nodes: %lu\n", nr_bucket); |
7ed7682f | 1687 | *approx_after = 0; |
5afadd12 | 1688 | if (ht->split_count) { |
973e5e1b MD |
1689 | int i; |
1690 | ||
4c42f1b8 LJ |
1691 | for (i = 0; i < split_count_mask + 1; i++) { |
1692 | *approx_after += uatomic_read(&ht->split_count[i].add); | |
1693 | *approx_after -= uatomic_read(&ht->split_count[i].del); | |
973e5e1b MD |
1694 | } |
1695 | } | |
273399de MD |
1696 | } |
1697 | ||
1475579c | 1698 | /* called with resize mutex held */ |
abc490a1 | 1699 | static |
4105056a | 1700 | void _do_cds_lfht_grow(struct cds_lfht *ht, |
1475579c | 1701 | unsigned long old_size, unsigned long new_size) |
abc490a1 | 1702 | { |
1475579c | 1703 | unsigned long old_order, new_order; |
1475579c | 1704 | |
93d46c39 LJ |
1705 | old_order = get_count_order_ulong(old_size); |
1706 | new_order = get_count_order_ulong(new_size); | |
1a401918 LJ |
1707 | dbg_printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", |
1708 | old_size, old_order, new_size, new_order); | |
1475579c | 1709 | assert(new_size > old_size); |
93d46c39 | 1710 | init_table(ht, old_order + 1, new_order); |
abc490a1 MD |
1711 | } |
1712 | ||
1713 | /* called with resize mutex held */ | |
1714 | static | |
4105056a | 1715 | void _do_cds_lfht_shrink(struct cds_lfht *ht, |
1475579c | 1716 | unsigned long old_size, unsigned long new_size) |
464a1ec9 | 1717 | { |
1475579c | 1718 | unsigned long old_order, new_order; |
464a1ec9 | 1719 | |
d0d8f9aa | 1720 | new_size = max(new_size, MIN_TABLE_SIZE); |
93d46c39 LJ |
1721 | old_order = get_count_order_ulong(old_size); |
1722 | new_order = get_count_order_ulong(new_size); | |
1a401918 LJ |
1723 | dbg_printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", |
1724 | old_size, old_order, new_size, new_order); | |
1475579c | 1725 | assert(new_size < old_size); |
1475579c | 1726 | |
1ee8f000 | 1727 | /* Remove and unlink all bucket nodes to remove. */ |
93d46c39 | 1728 | fini_table(ht, new_order + 1, old_order); |
464a1ec9 MD |
1729 | } |
1730 | ||
1475579c MD |
1731 | |
1732 | /* called with resize mutex held */ | |
1733 | static | |
1734 | void _do_cds_lfht_resize(struct cds_lfht *ht) | |
1735 | { | |
1736 | unsigned long new_size, old_size; | |
4105056a MD |
1737 | |
1738 | /* | |
1739 | * Resize table, re-do if the target size has changed under us. | |
1740 | */ | |
1741 | do { | |
d2be3620 MD |
1742 | assert(uatomic_read(&ht->in_progress_resize)); |
1743 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
1744 | break; | |
4105056a MD |
1745 | ht->t.resize_initiated = 1; |
1746 | old_size = ht->t.size; | |
1747 | new_size = CMM_LOAD_SHARED(ht->t.resize_target); | |
1748 | if (old_size < new_size) | |
1749 | _do_cds_lfht_grow(ht, old_size, new_size); | |
1750 | else if (old_size > new_size) | |
1751 | _do_cds_lfht_shrink(ht, old_size, new_size); | |
1752 | ht->t.resize_initiated = 0; | |
1753 | /* write resize_initiated before read resize_target */ | |
1754 | cmm_smp_mb(); | |
4d676753 | 1755 | } while (ht->t.size != CMM_LOAD_SHARED(ht->t.resize_target)); |
1475579c MD |
1756 | } |
1757 | ||
abc490a1 | 1758 | static |
ab65b890 | 1759 | unsigned long resize_target_grow(struct cds_lfht *ht, unsigned long new_size) |
464a1ec9 | 1760 | { |
ab65b890 | 1761 | return _uatomic_xchg_monotonic_increase(&ht->t.resize_target, new_size); |
464a1ec9 MD |
1762 | } |
1763 | ||
1475579c | 1764 | static |
4105056a | 1765 | void resize_target_update_count(struct cds_lfht *ht, |
b8af5011 | 1766 | unsigned long count) |
1475579c | 1767 | { |
d0d8f9aa | 1768 | count = max(count, MIN_TABLE_SIZE); |
4105056a | 1769 | uatomic_set(&ht->t.resize_target, count); |
1475579c MD |
1770 | } |
1771 | ||
1772 | void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size) | |
464a1ec9 | 1773 | { |
4105056a MD |
1774 | resize_target_update_count(ht, new_size); |
1775 | CMM_STORE_SHARED(ht->t.resize_initiated, 1); | |
5f511391 | 1776 | ht->cds_lfht_rcu_thread_offline(); |
1475579c MD |
1777 | pthread_mutex_lock(&ht->resize_mutex); |
1778 | _do_cds_lfht_resize(ht); | |
1779 | pthread_mutex_unlock(&ht->resize_mutex); | |
5f511391 | 1780 | ht->cds_lfht_rcu_thread_online(); |
abc490a1 | 1781 | } |
464a1ec9 | 1782 | |
abc490a1 MD |
1783 | static |
1784 | void do_resize_cb(struct rcu_head *head) | |
1785 | { | |
1786 | struct rcu_resize_work *work = | |
1787 | caa_container_of(head, struct rcu_resize_work, head); | |
14044b37 | 1788 | struct cds_lfht *ht = work->ht; |
abc490a1 | 1789 | |
5f511391 | 1790 | ht->cds_lfht_rcu_thread_offline(); |
abc490a1 | 1791 | pthread_mutex_lock(&ht->resize_mutex); |
14044b37 | 1792 | _do_cds_lfht_resize(ht); |
abc490a1 | 1793 | pthread_mutex_unlock(&ht->resize_mutex); |
5f511391 | 1794 | ht->cds_lfht_rcu_thread_online(); |
98808fb1 | 1795 | poison_free(work); |
848d4088 MD |
1796 | cmm_smp_mb(); /* finish resize before decrement */ |
1797 | uatomic_dec(&ht->in_progress_resize); | |
464a1ec9 MD |
1798 | } |
1799 | ||
abc490a1 | 1800 | static |
f1f119ee | 1801 | void __cds_lfht_resize_lazy_launch(struct cds_lfht *ht) |
ab7d5fc6 | 1802 | { |
abc490a1 MD |
1803 | struct rcu_resize_work *work; |
1804 | ||
4105056a MD |
1805 | /* Store resize_target before read resize_initiated */ |
1806 | cmm_smp_mb(); | |
ab65b890 | 1807 | if (!CMM_LOAD_SHARED(ht->t.resize_initiated)) { |
848d4088 | 1808 | uatomic_inc(&ht->in_progress_resize); |
59290e9d | 1809 | cmm_smp_mb(); /* increment resize count before load destroy */ |
ed35e6d8 MD |
1810 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) { |
1811 | uatomic_dec(&ht->in_progress_resize); | |
59290e9d | 1812 | return; |
ed35e6d8 | 1813 | } |
f9830efd MD |
1814 | work = malloc(sizeof(*work)); |
1815 | work->ht = ht; | |
14044b37 | 1816 | ht->cds_lfht_call_rcu(&work->head, do_resize_cb); |
4105056a | 1817 | CMM_STORE_SHARED(ht->t.resize_initiated, 1); |
f9830efd | 1818 | } |
ab7d5fc6 | 1819 | } |
3171717f | 1820 | |
f1f119ee LJ |
1821 | static |
1822 | void cds_lfht_resize_lazy_grow(struct cds_lfht *ht, unsigned long size, int growth) | |
1823 | { | |
1824 | unsigned long target_size = size << growth; | |
1825 | ||
1826 | if (resize_target_grow(ht, target_size) >= target_size) | |
1827 | return; | |
1828 | ||
1829 | __cds_lfht_resize_lazy_launch(ht); | |
1830 | } | |
1831 | ||
89bb121d LJ |
1832 | /* |
1833 | * We favor grow operations over shrink. A shrink operation never occurs | |
1834 | * if a grow operation is queued for lazy execution. A grow operation | |
1835 | * cancels any pending shrink lazy execution. | |
1836 | */ | |
3171717f | 1837 | static |
4105056a | 1838 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, |
3171717f MD |
1839 | unsigned long count) |
1840 | { | |
b8af5011 MD |
1841 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) |
1842 | return; | |
d0d8f9aa | 1843 | count = max(count, MIN_TABLE_SIZE); |
89bb121d LJ |
1844 | if (count == size) |
1845 | return; /* Already the right size, no resize needed */ | |
1846 | if (count > size) { /* lazy grow */ | |
1847 | if (resize_target_grow(ht, count) >= count) | |
1848 | return; | |
1849 | } else { /* lazy shrink */ | |
1850 | for (;;) { | |
1851 | unsigned long s; | |
1852 | ||
1853 | s = uatomic_cmpxchg(&ht->t.resize_target, size, count); | |
1854 | if (s == size) | |
1855 | break; /* no resize needed */ | |
1856 | if (s > size) | |
1857 | return; /* growing is/(was just) in progress */ | |
1858 | if (s <= count) | |
1859 | return; /* some other thread do shrink */ | |
1860 | size = s; | |
1861 | } | |
1862 | } | |
f1f119ee | 1863 | __cds_lfht_resize_lazy_launch(ht); |
3171717f | 1864 | } |