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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; |
0722081a LJ |
268 | unsigned long min_alloc_buckets_order; |
269 | unsigned long min_nr_alloc_buckets; | |
747d725c | 270 | unsigned long max_nr_buckets; |
b8af5011 | 271 | int flags; |
5f511391 MD |
272 | /* |
273 | * We need to put the work threads offline (QSBR) when taking this | |
274 | * mutex, because we use synchronize_rcu within this mutex critical | |
275 | * section, which waits on read-side critical sections, and could | |
276 | * therefore cause grace-period deadlock if we hold off RCU G.P. | |
277 | * completion. | |
278 | */ | |
464a1ec9 | 279 | pthread_mutex_t resize_mutex; /* resize mutex: add/del mutex */ |
33c7c748 | 280 | unsigned int in_progress_resize, in_progress_destroy; |
14044b37 | 281 | void (*cds_lfht_call_rcu)(struct rcu_head *head, |
abc490a1 | 282 | void (*func)(struct rcu_head *head)); |
1475579c | 283 | void (*cds_lfht_synchronize_rcu)(void); |
01dbfa62 MD |
284 | void (*cds_lfht_rcu_read_lock)(void); |
285 | void (*cds_lfht_rcu_read_unlock)(void); | |
5f511391 MD |
286 | void (*cds_lfht_rcu_thread_offline)(void); |
287 | void (*cds_lfht_rcu_thread_online)(void); | |
b7d619b0 MD |
288 | void (*cds_lfht_rcu_register_thread)(void); |
289 | void (*cds_lfht_rcu_unregister_thread)(void); | |
290 | pthread_attr_t *resize_attr; /* Resize threads attributes */ | |
7de5ccfd | 291 | long count; /* global approximate item count */ |
4c42f1b8 | 292 | struct ht_items_count *split_count; /* split item count */ |
2ed95849 MD |
293 | }; |
294 | ||
7f52427b MD |
295 | /* |
296 | * rcu_resize_work: Contains arguments passed to RCU worker thread | |
297 | * responsible for performing lazy resize. | |
298 | */ | |
abc490a1 MD |
299 | struct rcu_resize_work { |
300 | struct rcu_head head; | |
14044b37 | 301 | struct cds_lfht *ht; |
abc490a1 | 302 | }; |
2ed95849 | 303 | |
7f52427b MD |
304 | /* |
305 | * partition_resize_work: Contains arguments passed to worker threads | |
306 | * executing the hash table resize on partitions of the hash table | |
307 | * assigned to each processor's worker thread. | |
308 | */ | |
b7d619b0 | 309 | struct partition_resize_work { |
1af6e26e | 310 | pthread_t thread_id; |
b7d619b0 MD |
311 | struct cds_lfht *ht; |
312 | unsigned long i, start, len; | |
313 | void (*fct)(struct cds_lfht *ht, unsigned long i, | |
314 | unsigned long start, unsigned long len); | |
315 | }; | |
316 | ||
76a73da8 | 317 | static |
83beee94 | 318 | void _cds_lfht_add(struct cds_lfht *ht, |
0422d92c | 319 | cds_lfht_match_fct match, |
996ff57c | 320 | const void *key, |
83beee94 MD |
321 | unsigned long size, |
322 | struct cds_lfht_node *node, | |
323 | struct cds_lfht_iter *unique_ret, | |
1ee8f000 | 324 | int bucket); |
48ed1c18 | 325 | |
abc490a1 MD |
326 | /* |
327 | * Algorithm to reverse bits in a word by lookup table, extended to | |
328 | * 64-bit words. | |
f9830efd | 329 | * Source: |
abc490a1 | 330 | * http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable |
f9830efd | 331 | * Originally from Public Domain. |
abc490a1 MD |
332 | */ |
333 | ||
334 | static const uint8_t BitReverseTable256[256] = | |
2ed95849 | 335 | { |
abc490a1 MD |
336 | #define R2(n) (n), (n) + 2*64, (n) + 1*64, (n) + 3*64 |
337 | #define R4(n) R2(n), R2((n) + 2*16), R2((n) + 1*16), R2((n) + 3*16) | |
338 | #define R6(n) R4(n), R4((n) + 2*4 ), R4((n) + 1*4 ), R4((n) + 3*4 ) | |
339 | R6(0), R6(2), R6(1), R6(3) | |
340 | }; | |
341 | #undef R2 | |
342 | #undef R4 | |
343 | #undef R6 | |
2ed95849 | 344 | |
abc490a1 MD |
345 | static |
346 | uint8_t bit_reverse_u8(uint8_t v) | |
347 | { | |
348 | return BitReverseTable256[v]; | |
349 | } | |
ab7d5fc6 | 350 | |
abc490a1 MD |
351 | static __attribute__((unused)) |
352 | uint32_t bit_reverse_u32(uint32_t v) | |
353 | { | |
354 | return ((uint32_t) bit_reverse_u8(v) << 24) | | |
355 | ((uint32_t) bit_reverse_u8(v >> 8) << 16) | | |
356 | ((uint32_t) bit_reverse_u8(v >> 16) << 8) | | |
357 | ((uint32_t) bit_reverse_u8(v >> 24)); | |
2ed95849 MD |
358 | } |
359 | ||
abc490a1 MD |
360 | static __attribute__((unused)) |
361 | uint64_t bit_reverse_u64(uint64_t v) | |
2ed95849 | 362 | { |
abc490a1 MD |
363 | return ((uint64_t) bit_reverse_u8(v) << 56) | |
364 | ((uint64_t) bit_reverse_u8(v >> 8) << 48) | | |
365 | ((uint64_t) bit_reverse_u8(v >> 16) << 40) | | |
366 | ((uint64_t) bit_reverse_u8(v >> 24) << 32) | | |
367 | ((uint64_t) bit_reverse_u8(v >> 32) << 24) | | |
368 | ((uint64_t) bit_reverse_u8(v >> 40) << 16) | | |
369 | ((uint64_t) bit_reverse_u8(v >> 48) << 8) | | |
370 | ((uint64_t) bit_reverse_u8(v >> 56)); | |
371 | } | |
372 | ||
373 | static | |
374 | unsigned long bit_reverse_ulong(unsigned long v) | |
375 | { | |
376 | #if (CAA_BITS_PER_LONG == 32) | |
377 | return bit_reverse_u32(v); | |
378 | #else | |
379 | return bit_reverse_u64(v); | |
380 | #endif | |
381 | } | |
382 | ||
f9830efd | 383 | /* |
24365af7 MD |
384 | * fls: returns the position of the most significant bit. |
385 | * Returns 0 if no bit is set, else returns the position of the most | |
386 | * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit). | |
f9830efd | 387 | */ |
24365af7 MD |
388 | #if defined(__i386) || defined(__x86_64) |
389 | static inline | |
390 | unsigned int fls_u32(uint32_t x) | |
f9830efd | 391 | { |
24365af7 MD |
392 | int r; |
393 | ||
394 | asm("bsrl %1,%0\n\t" | |
395 | "jnz 1f\n\t" | |
396 | "movl $-1,%0\n\t" | |
397 | "1:\n\t" | |
398 | : "=r" (r) : "rm" (x)); | |
399 | return r + 1; | |
400 | } | |
401 | #define HAS_FLS_U32 | |
402 | #endif | |
403 | ||
404 | #if defined(__x86_64) | |
405 | static inline | |
406 | unsigned int fls_u64(uint64_t x) | |
407 | { | |
408 | long r; | |
409 | ||
410 | asm("bsrq %1,%0\n\t" | |
411 | "jnz 1f\n\t" | |
412 | "movq $-1,%0\n\t" | |
413 | "1:\n\t" | |
414 | : "=r" (r) : "rm" (x)); | |
415 | return r + 1; | |
416 | } | |
417 | #define HAS_FLS_U64 | |
418 | #endif | |
419 | ||
420 | #ifndef HAS_FLS_U64 | |
421 | static __attribute__((unused)) | |
422 | unsigned int fls_u64(uint64_t x) | |
423 | { | |
424 | unsigned int r = 64; | |
425 | ||
426 | if (!x) | |
427 | return 0; | |
428 | ||
429 | if (!(x & 0xFFFFFFFF00000000ULL)) { | |
430 | x <<= 32; | |
431 | r -= 32; | |
432 | } | |
433 | if (!(x & 0xFFFF000000000000ULL)) { | |
434 | x <<= 16; | |
435 | r -= 16; | |
436 | } | |
437 | if (!(x & 0xFF00000000000000ULL)) { | |
438 | x <<= 8; | |
439 | r -= 8; | |
440 | } | |
441 | if (!(x & 0xF000000000000000ULL)) { | |
442 | x <<= 4; | |
443 | r -= 4; | |
444 | } | |
445 | if (!(x & 0xC000000000000000ULL)) { | |
446 | x <<= 2; | |
447 | r -= 2; | |
448 | } | |
449 | if (!(x & 0x8000000000000000ULL)) { | |
450 | x <<= 1; | |
451 | r -= 1; | |
452 | } | |
453 | return r; | |
454 | } | |
455 | #endif | |
456 | ||
457 | #ifndef HAS_FLS_U32 | |
458 | static __attribute__((unused)) | |
459 | unsigned int fls_u32(uint32_t x) | |
460 | { | |
461 | unsigned int r = 32; | |
f9830efd | 462 | |
24365af7 MD |
463 | if (!x) |
464 | return 0; | |
465 | if (!(x & 0xFFFF0000U)) { | |
466 | x <<= 16; | |
467 | r -= 16; | |
468 | } | |
469 | if (!(x & 0xFF000000U)) { | |
470 | x <<= 8; | |
471 | r -= 8; | |
472 | } | |
473 | if (!(x & 0xF0000000U)) { | |
474 | x <<= 4; | |
475 | r -= 4; | |
476 | } | |
477 | if (!(x & 0xC0000000U)) { | |
478 | x <<= 2; | |
479 | r -= 2; | |
480 | } | |
481 | if (!(x & 0x80000000U)) { | |
482 | x <<= 1; | |
483 | r -= 1; | |
484 | } | |
485 | return r; | |
486 | } | |
487 | #endif | |
488 | ||
489 | unsigned int fls_ulong(unsigned long x) | |
f9830efd | 490 | { |
6887cc5e | 491 | #if (CAA_BITS_PER_LONG == 32) |
24365af7 MD |
492 | return fls_u32(x); |
493 | #else | |
494 | return fls_u64(x); | |
495 | #endif | |
496 | } | |
f9830efd | 497 | |
920f8ef6 LJ |
498 | /* |
499 | * Return the minimum order for which x <= (1UL << order). | |
500 | * Return -1 if x is 0. | |
501 | */ | |
24365af7 MD |
502 | int get_count_order_u32(uint32_t x) |
503 | { | |
920f8ef6 LJ |
504 | if (!x) |
505 | return -1; | |
24365af7 | 506 | |
920f8ef6 | 507 | return fls_u32(x - 1); |
24365af7 MD |
508 | } |
509 | ||
920f8ef6 LJ |
510 | /* |
511 | * Return the minimum order for which x <= (1UL << order). | |
512 | * Return -1 if x is 0. | |
513 | */ | |
24365af7 MD |
514 | int get_count_order_ulong(unsigned long x) |
515 | { | |
920f8ef6 LJ |
516 | if (!x) |
517 | return -1; | |
24365af7 | 518 | |
920f8ef6 | 519 | return fls_ulong(x - 1); |
f9830efd MD |
520 | } |
521 | ||
98808fb1 | 522 | #ifdef POISON_FREE |
5afadd12 LJ |
523 | #define poison_free(ptr) \ |
524 | do { \ | |
525 | if (ptr) { \ | |
526 | memset(ptr, 0x42, sizeof(*(ptr))); \ | |
527 | free(ptr); \ | |
528 | } \ | |
98808fb1 MD |
529 | } while (0) |
530 | #else | |
531 | #define poison_free(ptr) free(ptr) | |
532 | #endif | |
533 | ||
f9830efd | 534 | static |
ab65b890 | 535 | void cds_lfht_resize_lazy_grow(struct cds_lfht *ht, unsigned long size, int growth); |
f9830efd | 536 | |
f8994aee | 537 | static |
4105056a | 538 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, |
f8994aee MD |
539 | unsigned long count); |
540 | ||
df44348d | 541 | static long nr_cpus_mask = -1; |
4c42f1b8 LJ |
542 | static long split_count_mask = -1; |
543 | ||
4ddbb355 | 544 | #if defined(HAVE_SYSCONF) |
4c42f1b8 LJ |
545 | static void ht_init_nr_cpus_mask(void) |
546 | { | |
547 | long maxcpus; | |
548 | ||
549 | maxcpus = sysconf(_SC_NPROCESSORS_CONF); | |
550 | if (maxcpus <= 0) { | |
551 | nr_cpus_mask = -2; | |
552 | return; | |
553 | } | |
554 | /* | |
555 | * round up number of CPUs to next power of two, so we | |
556 | * can use & for modulo. | |
557 | */ | |
558 | maxcpus = 1UL << get_count_order_ulong(maxcpus); | |
559 | nr_cpus_mask = maxcpus - 1; | |
560 | } | |
4ddbb355 LJ |
561 | #else /* #if defined(HAVE_SYSCONF) */ |
562 | static void ht_init_nr_cpus_mask(void) | |
563 | { | |
564 | nr_cpus_mask = -2; | |
565 | } | |
566 | #endif /* #else #if defined(HAVE_SYSCONF) */ | |
df44348d MD |
567 | |
568 | static | |
5afadd12 | 569 | void alloc_split_items_count(struct cds_lfht *ht) |
df44348d MD |
570 | { |
571 | struct ht_items_count *count; | |
572 | ||
4c42f1b8 LJ |
573 | if (nr_cpus_mask == -1) { |
574 | ht_init_nr_cpus_mask(); | |
4ddbb355 LJ |
575 | if (nr_cpus_mask < 0) |
576 | split_count_mask = DEFAULT_SPLIT_COUNT_MASK; | |
577 | else | |
578 | split_count_mask = nr_cpus_mask; | |
df44348d | 579 | } |
4c42f1b8 | 580 | |
4ddbb355 | 581 | assert(split_count_mask >= 0); |
5afadd12 LJ |
582 | |
583 | if (ht->flags & CDS_LFHT_ACCOUNTING) { | |
584 | ht->split_count = calloc(split_count_mask + 1, sizeof(*count)); | |
585 | assert(ht->split_count); | |
586 | } else { | |
587 | ht->split_count = NULL; | |
588 | } | |
df44348d MD |
589 | } |
590 | ||
591 | static | |
5afadd12 | 592 | void free_split_items_count(struct cds_lfht *ht) |
df44348d | 593 | { |
5afadd12 | 594 | poison_free(ht->split_count); |
df44348d MD |
595 | } |
596 | ||
14360f1c | 597 | #if defined(HAVE_SCHED_GETCPU) |
df44348d | 598 | static |
14360f1c | 599 | int ht_get_split_count_index(unsigned long hash) |
df44348d MD |
600 | { |
601 | int cpu; | |
602 | ||
4c42f1b8 | 603 | assert(split_count_mask >= 0); |
df44348d | 604 | cpu = sched_getcpu(); |
8ed51e04 | 605 | if (caa_unlikely(cpu < 0)) |
14360f1c | 606 | return hash & split_count_mask; |
df44348d | 607 | else |
4c42f1b8 | 608 | return cpu & split_count_mask; |
df44348d | 609 | } |
14360f1c LJ |
610 | #else /* #if defined(HAVE_SCHED_GETCPU) */ |
611 | static | |
612 | int ht_get_split_count_index(unsigned long hash) | |
613 | { | |
614 | return hash & split_count_mask; | |
615 | } | |
616 | #endif /* #else #if defined(HAVE_SCHED_GETCPU) */ | |
df44348d MD |
617 | |
618 | static | |
14360f1c | 619 | void ht_count_add(struct cds_lfht *ht, unsigned long size, unsigned long hash) |
df44348d | 620 | { |
4c42f1b8 LJ |
621 | unsigned long split_count; |
622 | int index; | |
df44348d | 623 | |
8ed51e04 | 624 | if (caa_unlikely(!ht->split_count)) |
3171717f | 625 | return; |
14360f1c | 626 | index = ht_get_split_count_index(hash); |
4c42f1b8 | 627 | split_count = uatomic_add_return(&ht->split_count[index].add, 1); |
8ed51e04 | 628 | if (caa_unlikely(!(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) { |
e3ecefd6 | 629 | long count; |
df44348d | 630 | |
4c42f1b8 | 631 | dbg_printf("add split count %lu\n", split_count); |
df44348d MD |
632 | count = uatomic_add_return(&ht->count, |
633 | 1UL << COUNT_COMMIT_ORDER); | |
634 | /* If power of 2 */ | |
635 | if (!(count & (count - 1))) { | |
4105056a | 636 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) < size) |
f8994aee | 637 | return; |
e3ecefd6 | 638 | dbg_printf("add set global %ld\n", count); |
4105056a | 639 | cds_lfht_resize_lazy_count(ht, size, |
6ea6bc67 | 640 | count >> (CHAIN_LEN_TARGET - 1)); |
df44348d MD |
641 | } |
642 | } | |
643 | } | |
644 | ||
645 | static | |
14360f1c | 646 | void ht_count_del(struct cds_lfht *ht, unsigned long size, unsigned long hash) |
df44348d | 647 | { |
4c42f1b8 LJ |
648 | unsigned long split_count; |
649 | int index; | |
df44348d | 650 | |
8ed51e04 | 651 | if (caa_unlikely(!ht->split_count)) |
3171717f | 652 | return; |
14360f1c | 653 | index = ht_get_split_count_index(hash); |
4c42f1b8 | 654 | split_count = uatomic_add_return(&ht->split_count[index].del, 1); |
8ed51e04 | 655 | if (caa_unlikely(!(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) { |
e3ecefd6 | 656 | long count; |
df44348d | 657 | |
4c42f1b8 | 658 | dbg_printf("del split count %lu\n", split_count); |
df44348d | 659 | count = uatomic_add_return(&ht->count, |
3171717f | 660 | -(1UL << COUNT_COMMIT_ORDER)); |
df44348d MD |
661 | /* If power of 2 */ |
662 | if (!(count & (count - 1))) { | |
4105056a | 663 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) >= size) |
f8994aee | 664 | return; |
e3ecefd6 MD |
665 | dbg_printf("del set global %ld\n", count); |
666 | /* | |
c941bb9e | 667 | * Don't shrink table if the number of nodes is below a |
e3ecefd6 MD |
668 | * certain threshold. |
669 | */ | |
4c42f1b8 | 670 | if (count < (1UL << COUNT_COMMIT_ORDER) * (split_count_mask + 1)) |
e3ecefd6 | 671 | return; |
4105056a | 672 | cds_lfht_resize_lazy_count(ht, size, |
6ea6bc67 | 673 | count >> (CHAIN_LEN_TARGET - 1)); |
df44348d MD |
674 | } |
675 | } | |
676 | } | |
677 | ||
f9830efd | 678 | static |
4105056a | 679 | void check_resize(struct cds_lfht *ht, unsigned long size, uint32_t chain_len) |
f9830efd | 680 | { |
f8994aee MD |
681 | unsigned long count; |
682 | ||
b8af5011 MD |
683 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) |
684 | return; | |
f8994aee MD |
685 | count = uatomic_read(&ht->count); |
686 | /* | |
687 | * Use bucket-local length for small table expand and for | |
688 | * environments lacking per-cpu data support. | |
689 | */ | |
690 | if (count >= (1UL << COUNT_COMMIT_ORDER)) | |
691 | return; | |
24365af7 | 692 | if (chain_len > 100) |
f0c29ed7 | 693 | dbg_printf("WARNING: large chain length: %u.\n", |
24365af7 | 694 | chain_len); |
3390d470 | 695 | if (chain_len >= CHAIN_LEN_RESIZE_THRESHOLD) |
ab65b890 | 696 | cds_lfht_resize_lazy_grow(ht, size, |
01370f0b | 697 | get_count_order_u32(chain_len - (CHAIN_LEN_TARGET - 1))); |
f9830efd MD |
698 | } |
699 | ||
abc490a1 | 700 | static |
14044b37 | 701 | struct cds_lfht_node *clear_flag(struct cds_lfht_node *node) |
abc490a1 | 702 | { |
14044b37 | 703 | return (struct cds_lfht_node *) (((unsigned long) node) & ~FLAGS_MASK); |
abc490a1 MD |
704 | } |
705 | ||
706 | static | |
14044b37 | 707 | int is_removed(struct cds_lfht_node *node) |
abc490a1 | 708 | { |
d37166c6 | 709 | return ((unsigned long) node) & REMOVED_FLAG; |
abc490a1 MD |
710 | } |
711 | ||
712 | static | |
14044b37 | 713 | struct cds_lfht_node *flag_removed(struct cds_lfht_node *node) |
abc490a1 | 714 | { |
14044b37 | 715 | return (struct cds_lfht_node *) (((unsigned long) node) | REMOVED_FLAG); |
abc490a1 MD |
716 | } |
717 | ||
f5596c94 | 718 | static |
1ee8f000 | 719 | int is_bucket(struct cds_lfht_node *node) |
f5596c94 | 720 | { |
1ee8f000 | 721 | return ((unsigned long) node) & BUCKET_FLAG; |
f5596c94 MD |
722 | } |
723 | ||
724 | static | |
1ee8f000 | 725 | struct cds_lfht_node *flag_bucket(struct cds_lfht_node *node) |
f5596c94 | 726 | { |
1ee8f000 | 727 | return (struct cds_lfht_node *) (((unsigned long) node) | BUCKET_FLAG); |
f5596c94 | 728 | } |
bb7b2f26 MD |
729 | |
730 | static | |
731 | struct cds_lfht_node *get_end(void) | |
732 | { | |
733 | return (struct cds_lfht_node *) END_VALUE; | |
734 | } | |
735 | ||
736 | static | |
737 | int is_end(struct cds_lfht_node *node) | |
738 | { | |
739 | return clear_flag(node) == (struct cds_lfht_node *) END_VALUE; | |
740 | } | |
741 | ||
abc490a1 | 742 | static |
ab65b890 LJ |
743 | unsigned long _uatomic_xchg_monotonic_increase(unsigned long *ptr, |
744 | unsigned long v) | |
abc490a1 MD |
745 | { |
746 | unsigned long old1, old2; | |
747 | ||
748 | old1 = uatomic_read(ptr); | |
749 | do { | |
750 | old2 = old1; | |
751 | if (old2 >= v) | |
f9830efd | 752 | return old2; |
abc490a1 | 753 | } while ((old1 = uatomic_cmpxchg(ptr, old2, v)) != old2); |
ab65b890 | 754 | return old2; |
abc490a1 MD |
755 | } |
756 | ||
48f1b16d LJ |
757 | static |
758 | void cds_lfht_alloc_bucket_table(struct cds_lfht *ht, unsigned long order) | |
759 | { | |
760 | if (order == 0) { | |
0722081a | 761 | ht->t.tbl[0] = calloc(ht->min_nr_alloc_buckets, |
48f1b16d LJ |
762 | sizeof(struct cds_lfht_node)); |
763 | assert(ht->t.tbl[0]); | |
0722081a | 764 | } else if (order > ht->min_alloc_buckets_order) { |
48f1b16d LJ |
765 | ht->t.tbl[order] = calloc(1UL << (order -1), |
766 | sizeof(struct cds_lfht_node)); | |
767 | assert(ht->t.tbl[order]); | |
768 | } | |
0722081a | 769 | /* Nothing to do for 0 < order && order <= ht->min_alloc_buckets_order */ |
48f1b16d LJ |
770 | } |
771 | ||
772 | /* | |
773 | * cds_lfht_free_bucket_table() should be called with decreasing order. | |
774 | * When cds_lfht_free_bucket_table(0) is called, it means the whole | |
775 | * lfht is destroyed. | |
776 | */ | |
777 | static | |
778 | void cds_lfht_free_bucket_table(struct cds_lfht *ht, unsigned long order) | |
779 | { | |
780 | if (order == 0) | |
781 | poison_free(ht->t.tbl[0]); | |
0722081a | 782 | else if (order > ht->min_alloc_buckets_order) |
48f1b16d | 783 | poison_free(ht->t.tbl[order]); |
0722081a | 784 | /* Nothing to do for 0 < order && order <= ht->min_alloc_buckets_order */ |
48f1b16d LJ |
785 | } |
786 | ||
9d72a73f LJ |
787 | static inline |
788 | struct cds_lfht_node *bucket_at(struct cds_lfht *ht, unsigned long index) | |
f4a9cc0b | 789 | { |
9d72a73f | 790 | unsigned long order; |
ef6e6171 | 791 | |
9d72a73f | 792 | if ((__builtin_constant_p(index) && index == 0) |
0722081a | 793 | || index < ht->min_nr_alloc_buckets) { |
9d72a73f | 794 | dbg_printf("bucket index %lu order 0 aridx 0\n", index); |
dcc26ef4 | 795 | return &ht->t.tbl[0][index]; |
ef6e6171 | 796 | } |
a4ea2223 LJ |
797 | /* |
798 | * equivalent to get_count_order_ulong(index + 1), but optimizes | |
799 | * away the non-existing 0 special-case for | |
800 | * get_count_order_ulong. | |
801 | */ | |
802 | order = fls_ulong(index); | |
9d72a73f LJ |
803 | dbg_printf("bucket index %lu order %lu aridx %lu\n", |
804 | index, order, index & ((1UL << (order - 1)) - 1)); | |
dcc26ef4 | 805 | return &ht->t.tbl[order][index & ((1UL << (order - 1)) - 1)]; |
f4a9cc0b LJ |
806 | } |
807 | ||
9d72a73f LJ |
808 | static inline |
809 | struct cds_lfht_node *lookup_bucket(struct cds_lfht *ht, unsigned long size, | |
810 | unsigned long hash) | |
811 | { | |
812 | assert(size > 0); | |
813 | return bucket_at(ht, hash & (size - 1)); | |
814 | } | |
815 | ||
273399de MD |
816 | /* |
817 | * Remove all logically deleted nodes from a bucket up to a certain node key. | |
818 | */ | |
819 | static | |
1ee8f000 | 820 | void _cds_lfht_gc_bucket(struct cds_lfht_node *bucket, struct cds_lfht_node *node) |
273399de | 821 | { |
14044b37 | 822 | struct cds_lfht_node *iter_prev, *iter, *next, *new_next; |
273399de | 823 | |
1ee8f000 LJ |
824 | assert(!is_bucket(bucket)); |
825 | assert(!is_removed(bucket)); | |
826 | assert(!is_bucket(node)); | |
c90201ac | 827 | assert(!is_removed(node)); |
273399de | 828 | for (;;) { |
1ee8f000 LJ |
829 | iter_prev = bucket; |
830 | /* We can always skip the bucket node initially */ | |
04db56f8 | 831 | iter = rcu_dereference(iter_prev->next); |
b4cb483f | 832 | assert(!is_removed(iter)); |
04db56f8 | 833 | assert(iter_prev->reverse_hash <= node->reverse_hash); |
bd4db153 | 834 | /* |
1ee8f000 | 835 | * We should never be called with bucket (start of chain) |
bd4db153 MD |
836 | * and logically removed node (end of path compression |
837 | * marker) being the actual same node. This would be a | |
838 | * bug in the algorithm implementation. | |
839 | */ | |
1ee8f000 | 840 | assert(bucket != node); |
273399de | 841 | for (;;) { |
8ed51e04 | 842 | if (caa_unlikely(is_end(iter))) |
f9c80341 | 843 | return; |
04db56f8 | 844 | if (caa_likely(clear_flag(iter)->reverse_hash > node->reverse_hash)) |
f9c80341 | 845 | return; |
04db56f8 | 846 | next = rcu_dereference(clear_flag(iter)->next); |
8ed51e04 | 847 | if (caa_likely(is_removed(next))) |
273399de | 848 | break; |
b453eae1 | 849 | iter_prev = clear_flag(iter); |
273399de MD |
850 | iter = next; |
851 | } | |
b198f0fd | 852 | assert(!is_removed(iter)); |
1ee8f000 LJ |
853 | if (is_bucket(iter)) |
854 | new_next = flag_bucket(clear_flag(next)); | |
f5596c94 MD |
855 | else |
856 | new_next = clear_flag(next); | |
04db56f8 | 857 | (void) uatomic_cmpxchg(&iter_prev->next, iter, new_next); |
273399de | 858 | } |
f9c80341 | 859 | return; |
273399de MD |
860 | } |
861 | ||
9357c415 MD |
862 | static |
863 | int _cds_lfht_replace(struct cds_lfht *ht, unsigned long size, | |
864 | struct cds_lfht_node *old_node, | |
3fb86f26 | 865 | struct cds_lfht_node *old_next, |
9357c415 MD |
866 | struct cds_lfht_node *new_node) |
867 | { | |
04db56f8 | 868 | struct cds_lfht_node *bucket, *ret_next; |
9357c415 MD |
869 | |
870 | if (!old_node) /* Return -ENOENT if asked to replace NULL node */ | |
7801dadd | 871 | return -ENOENT; |
9357c415 MD |
872 | |
873 | assert(!is_removed(old_node)); | |
1ee8f000 | 874 | assert(!is_bucket(old_node)); |
9357c415 | 875 | assert(!is_removed(new_node)); |
1ee8f000 | 876 | assert(!is_bucket(new_node)); |
9357c415 | 877 | assert(new_node != old_node); |
3fb86f26 | 878 | for (;;) { |
9357c415 | 879 | /* Insert after node to be replaced */ |
9357c415 MD |
880 | if (is_removed(old_next)) { |
881 | /* | |
882 | * Too late, the old node has been removed under us | |
883 | * between lookup and replace. Fail. | |
884 | */ | |
7801dadd | 885 | return -ENOENT; |
9357c415 | 886 | } |
1ee8f000 | 887 | assert(!is_bucket(old_next)); |
9357c415 | 888 | assert(new_node != clear_flag(old_next)); |
04db56f8 | 889 | new_node->next = clear_flag(old_next); |
9357c415 MD |
890 | /* |
891 | * Here is the whole trick for lock-free replace: we add | |
892 | * the replacement node _after_ the node we want to | |
893 | * replace by atomically setting its next pointer at the | |
894 | * same time we set its removal flag. Given that | |
895 | * the lookups/get next use an iterator aware of the | |
896 | * next pointer, they will either skip the old node due | |
897 | * to the removal flag and see the new node, or use | |
898 | * the old node, but will not see the new one. | |
899 | */ | |
04db56f8 | 900 | ret_next = uatomic_cmpxchg(&old_node->next, |
9357c415 | 901 | old_next, flag_removed(new_node)); |
3fb86f26 | 902 | if (ret_next == old_next) |
7801dadd | 903 | break; /* We performed the replacement. */ |
3fb86f26 LJ |
904 | old_next = ret_next; |
905 | } | |
9357c415 | 906 | |
9357c415 MD |
907 | /* |
908 | * Ensure that the old node is not visible to readers anymore: | |
909 | * lookup for the node, and remove it (along with any other | |
910 | * logically removed node) if found. | |
911 | */ | |
04db56f8 LJ |
912 | bucket = lookup_bucket(ht, size, bit_reverse_ulong(old_node->reverse_hash)); |
913 | _cds_lfht_gc_bucket(bucket, new_node); | |
7801dadd | 914 | |
04db56f8 | 915 | assert(is_removed(rcu_dereference(old_node->next))); |
7801dadd | 916 | return 0; |
9357c415 MD |
917 | } |
918 | ||
83beee94 MD |
919 | /* |
920 | * A non-NULL unique_ret pointer uses the "add unique" (or uniquify) add | |
921 | * mode. A NULL unique_ret allows creation of duplicate keys. | |
922 | */ | |
abc490a1 | 923 | static |
83beee94 | 924 | void _cds_lfht_add(struct cds_lfht *ht, |
0422d92c | 925 | cds_lfht_match_fct match, |
996ff57c | 926 | const void *key, |
83beee94 MD |
927 | unsigned long size, |
928 | struct cds_lfht_node *node, | |
929 | struct cds_lfht_iter *unique_ret, | |
1ee8f000 | 930 | int bucket_flag) |
abc490a1 | 931 | { |
14044b37 | 932 | struct cds_lfht_node *iter_prev, *iter, *next, *new_node, *new_next, |
960c9e4f | 933 | *return_node; |
04db56f8 | 934 | struct cds_lfht_node *bucket; |
abc490a1 | 935 | |
1ee8f000 | 936 | assert(!is_bucket(node)); |
c90201ac | 937 | assert(!is_removed(node)); |
04db56f8 | 938 | bucket = lookup_bucket(ht, size, bit_reverse_ulong(node->reverse_hash)); |
abc490a1 | 939 | for (;;) { |
adc0de68 | 940 | uint32_t chain_len = 0; |
abc490a1 | 941 | |
11519af6 MD |
942 | /* |
943 | * iter_prev points to the non-removed node prior to the | |
944 | * insert location. | |
11519af6 | 945 | */ |
04db56f8 | 946 | iter_prev = bucket; |
1ee8f000 | 947 | /* We can always skip the bucket node initially */ |
04db56f8 LJ |
948 | iter = rcu_dereference(iter_prev->next); |
949 | assert(iter_prev->reverse_hash <= node->reverse_hash); | |
abc490a1 | 950 | for (;;) { |
8ed51e04 | 951 | if (caa_unlikely(is_end(iter))) |
273399de | 952 | goto insert; |
04db56f8 | 953 | if (caa_likely(clear_flag(iter)->reverse_hash > node->reverse_hash)) |
273399de | 954 | goto insert; |
238cc06e | 955 | |
1ee8f000 LJ |
956 | /* bucket node is the first node of the identical-hash-value chain */ |
957 | if (bucket_flag && clear_flag(iter)->reverse_hash == node->reverse_hash) | |
194fdbd1 | 958 | goto insert; |
238cc06e | 959 | |
04db56f8 | 960 | next = rcu_dereference(clear_flag(iter)->next); |
8ed51e04 | 961 | if (caa_unlikely(is_removed(next))) |
9dba85be | 962 | goto gc_node; |
238cc06e LJ |
963 | |
964 | /* uniquely add */ | |
83beee94 | 965 | if (unique_ret |
1ee8f000 | 966 | && !is_bucket(next) |
04db56f8 | 967 | && clear_flag(iter)->reverse_hash == node->reverse_hash) { |
238cc06e LJ |
968 | struct cds_lfht_iter d_iter = { .node = node, .next = iter, }; |
969 | ||
970 | /* | |
971 | * uniquely adding inserts the node as the first | |
972 | * node of the identical-hash-value node chain. | |
973 | * | |
974 | * This semantic ensures no duplicated keys | |
975 | * should ever be observable in the table | |
976 | * (including observe one node by one node | |
977 | * by forward iterations) | |
978 | */ | |
04db56f8 | 979 | cds_lfht_next_duplicate(ht, match, key, &d_iter); |
238cc06e LJ |
980 | if (!d_iter.node) |
981 | goto insert; | |
982 | ||
983 | *unique_ret = d_iter; | |
83beee94 | 984 | return; |
48ed1c18 | 985 | } |
238cc06e | 986 | |
11519af6 | 987 | /* Only account for identical reverse hash once */ |
04db56f8 | 988 | if (iter_prev->reverse_hash != clear_flag(iter)->reverse_hash |
1ee8f000 | 989 | && !is_bucket(next)) |
4105056a | 990 | check_resize(ht, size, ++chain_len); |
11519af6 | 991 | iter_prev = clear_flag(iter); |
273399de | 992 | iter = next; |
abc490a1 | 993 | } |
48ed1c18 | 994 | |
273399de | 995 | insert: |
7ec59d3b | 996 | assert(node != clear_flag(iter)); |
11519af6 | 997 | assert(!is_removed(iter_prev)); |
c90201ac | 998 | assert(!is_removed(iter)); |
f000907d | 999 | assert(iter_prev != node); |
1ee8f000 | 1000 | if (!bucket_flag) |
04db56f8 | 1001 | node->next = clear_flag(iter); |
f9c80341 | 1002 | else |
1ee8f000 LJ |
1003 | node->next = flag_bucket(clear_flag(iter)); |
1004 | if (is_bucket(iter)) | |
1005 | new_node = flag_bucket(node); | |
f5596c94 MD |
1006 | else |
1007 | new_node = node; | |
04db56f8 | 1008 | if (uatomic_cmpxchg(&iter_prev->next, iter, |
48ed1c18 | 1009 | new_node) != iter) { |
273399de | 1010 | continue; /* retry */ |
48ed1c18 | 1011 | } else { |
83beee94 | 1012 | return_node = node; |
960c9e4f | 1013 | goto end; |
48ed1c18 MD |
1014 | } |
1015 | ||
9dba85be MD |
1016 | gc_node: |
1017 | assert(!is_removed(iter)); | |
1ee8f000 LJ |
1018 | if (is_bucket(iter)) |
1019 | new_next = flag_bucket(clear_flag(next)); | |
f5596c94 MD |
1020 | else |
1021 | new_next = clear_flag(next); | |
04db56f8 | 1022 | (void) uatomic_cmpxchg(&iter_prev->next, iter, new_next); |
273399de | 1023 | /* retry */ |
464a1ec9 | 1024 | } |
9357c415 | 1025 | end: |
83beee94 MD |
1026 | if (unique_ret) { |
1027 | unique_ret->node = return_node; | |
1028 | /* unique_ret->next left unset, never used. */ | |
1029 | } | |
abc490a1 | 1030 | } |
464a1ec9 | 1031 | |
abc490a1 | 1032 | static |
860d07e8 | 1033 | int _cds_lfht_del(struct cds_lfht *ht, unsigned long size, |
4105056a | 1034 | struct cds_lfht_node *node, |
1ee8f000 | 1035 | int bucket_removal) |
abc490a1 | 1036 | { |
04db56f8 | 1037 | struct cds_lfht_node *bucket, *next, *old; |
5e28c532 | 1038 | |
9357c415 | 1039 | if (!node) /* Return -ENOENT if asked to delete NULL node */ |
743f9143 | 1040 | return -ENOENT; |
9357c415 | 1041 | |
7ec59d3b | 1042 | /* logically delete the node */ |
1ee8f000 | 1043 | assert(!is_bucket(node)); |
c90201ac | 1044 | assert(!is_removed(node)); |
04db56f8 | 1045 | old = rcu_dereference(node->next); |
7ec59d3b | 1046 | do { |
48ed1c18 MD |
1047 | struct cds_lfht_node *new_next; |
1048 | ||
7ec59d3b | 1049 | next = old; |
8ed51e04 | 1050 | if (caa_unlikely(is_removed(next))) |
743f9143 | 1051 | return -ENOENT; |
1ee8f000 LJ |
1052 | if (bucket_removal) |
1053 | assert(is_bucket(next)); | |
1475579c | 1054 | else |
1ee8f000 | 1055 | assert(!is_bucket(next)); |
48ed1c18 | 1056 | new_next = flag_removed(next); |
04db56f8 | 1057 | old = uatomic_cmpxchg(&node->next, next, new_next); |
7ec59d3b | 1058 | } while (old != next); |
7ec59d3b | 1059 | /* We performed the (logical) deletion. */ |
7ec59d3b MD |
1060 | |
1061 | /* | |
1062 | * Ensure that the node is not visible to readers anymore: lookup for | |
273399de MD |
1063 | * the node, and remove it (along with any other logically removed node) |
1064 | * if found. | |
11519af6 | 1065 | */ |
04db56f8 LJ |
1066 | bucket = lookup_bucket(ht, size, bit_reverse_ulong(node->reverse_hash)); |
1067 | _cds_lfht_gc_bucket(bucket, node); | |
743f9143 | 1068 | |
04db56f8 | 1069 | assert(is_removed(rcu_dereference(node->next))); |
743f9143 | 1070 | return 0; |
abc490a1 | 1071 | } |
2ed95849 | 1072 | |
b7d619b0 MD |
1073 | static |
1074 | void *partition_resize_thread(void *arg) | |
1075 | { | |
1076 | struct partition_resize_work *work = arg; | |
1077 | ||
1078 | work->ht->cds_lfht_rcu_register_thread(); | |
1079 | work->fct(work->ht, work->i, work->start, work->len); | |
1080 | work->ht->cds_lfht_rcu_unregister_thread(); | |
1081 | return NULL; | |
1082 | } | |
1083 | ||
1084 | static | |
1085 | void partition_resize_helper(struct cds_lfht *ht, unsigned long i, | |
1086 | unsigned long len, | |
1087 | void (*fct)(struct cds_lfht *ht, unsigned long i, | |
1088 | unsigned long start, unsigned long len)) | |
1089 | { | |
1090 | unsigned long partition_len; | |
1091 | struct partition_resize_work *work; | |
6083a889 MD |
1092 | int thread, ret; |
1093 | unsigned long nr_threads; | |
b7d619b0 | 1094 | |
6083a889 MD |
1095 | /* |
1096 | * Note: nr_cpus_mask + 1 is always power of 2. | |
1097 | * We spawn just the number of threads we need to satisfy the minimum | |
1098 | * partition size, up to the number of CPUs in the system. | |
1099 | */ | |
91452a6a MD |
1100 | if (nr_cpus_mask > 0) { |
1101 | nr_threads = min(nr_cpus_mask + 1, | |
1102 | len >> MIN_PARTITION_PER_THREAD_ORDER); | |
1103 | } else { | |
1104 | nr_threads = 1; | |
1105 | } | |
6083a889 MD |
1106 | partition_len = len >> get_count_order_ulong(nr_threads); |
1107 | work = calloc(nr_threads, sizeof(*work)); | |
b7d619b0 | 1108 | assert(work); |
6083a889 MD |
1109 | for (thread = 0; thread < nr_threads; thread++) { |
1110 | work[thread].ht = ht; | |
1111 | work[thread].i = i; | |
1112 | work[thread].len = partition_len; | |
1113 | work[thread].start = thread * partition_len; | |
1114 | work[thread].fct = fct; | |
1af6e26e | 1115 | ret = pthread_create(&(work[thread].thread_id), ht->resize_attr, |
6083a889 | 1116 | partition_resize_thread, &work[thread]); |
b7d619b0 MD |
1117 | assert(!ret); |
1118 | } | |
6083a889 | 1119 | for (thread = 0; thread < nr_threads; thread++) { |
1af6e26e | 1120 | ret = pthread_join(work[thread].thread_id, NULL); |
b7d619b0 MD |
1121 | assert(!ret); |
1122 | } | |
1123 | free(work); | |
b7d619b0 MD |
1124 | } |
1125 | ||
e8de508e MD |
1126 | /* |
1127 | * Holding RCU read lock to protect _cds_lfht_add against memory | |
1128 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
1129 | * problem). | |
9ee0fc9a | 1130 | * |
b7d619b0 | 1131 | * When we reach a certain length, we can split this population phase over |
9ee0fc9a MD |
1132 | * many worker threads, based on the number of CPUs available in the system. |
1133 | * This should therefore take care of not having the expand lagging behind too | |
1134 | * many concurrent insertion threads by using the scheduler's ability to | |
1ee8f000 | 1135 | * schedule bucket node population fairly with insertions. |
e8de508e | 1136 | */ |
4105056a | 1137 | static |
b7d619b0 MD |
1138 | void init_table_populate_partition(struct cds_lfht *ht, unsigned long i, |
1139 | unsigned long start, unsigned long len) | |
4105056a | 1140 | { |
9d72a73f | 1141 | unsigned long j, size = 1UL << (i - 1); |
4105056a | 1142 | |
d0d8f9aa | 1143 | assert(i > MIN_TABLE_ORDER); |
4105056a | 1144 | ht->cds_lfht_rcu_read_lock(); |
9d72a73f LJ |
1145 | for (j = size + start; j < size + start + len; j++) { |
1146 | struct cds_lfht_node *new_node = bucket_at(ht, j); | |
1147 | ||
1148 | assert(j >= size && j < (size << 1)); | |
1149 | dbg_printf("init populate: order %lu index %lu hash %lu\n", | |
1150 | i, j, j); | |
1151 | new_node->reverse_hash = bit_reverse_ulong(j); | |
1152 | _cds_lfht_add(ht, NULL, NULL, size, new_node, NULL, 1); | |
4105056a MD |
1153 | } |
1154 | ht->cds_lfht_rcu_read_unlock(); | |
b7d619b0 MD |
1155 | } |
1156 | ||
1157 | static | |
1158 | void init_table_populate(struct cds_lfht *ht, unsigned long i, | |
1159 | unsigned long len) | |
1160 | { | |
1161 | assert(nr_cpus_mask != -1); | |
6083a889 | 1162 | if (nr_cpus_mask < 0 || len < 2 * MIN_PARTITION_PER_THREAD) { |
b7d619b0 MD |
1163 | ht->cds_lfht_rcu_thread_online(); |
1164 | init_table_populate_partition(ht, i, 0, len); | |
1165 | ht->cds_lfht_rcu_thread_offline(); | |
1166 | return; | |
1167 | } | |
1168 | partition_resize_helper(ht, i, len, init_table_populate_partition); | |
4105056a MD |
1169 | } |
1170 | ||
abc490a1 | 1171 | static |
4105056a | 1172 | void init_table(struct cds_lfht *ht, |
93d46c39 | 1173 | unsigned long first_order, unsigned long last_order) |
24365af7 | 1174 | { |
93d46c39 | 1175 | unsigned long i; |
24365af7 | 1176 | |
93d46c39 LJ |
1177 | dbg_printf("init table: first_order %lu last_order %lu\n", |
1178 | first_order, last_order); | |
d0d8f9aa | 1179 | assert(first_order > MIN_TABLE_ORDER); |
93d46c39 | 1180 | for (i = first_order; i <= last_order; i++) { |
4105056a | 1181 | unsigned long len; |
24365af7 | 1182 | |
4f6e90b7 | 1183 | len = 1UL << (i - 1); |
f0c29ed7 | 1184 | dbg_printf("init order %lu len: %lu\n", i, len); |
4d676753 MD |
1185 | |
1186 | /* Stop expand if the resize target changes under us */ | |
4f6e90b7 | 1187 | if (CMM_LOAD_SHARED(ht->t.resize_target) < (1UL << i)) |
4d676753 MD |
1188 | break; |
1189 | ||
48f1b16d | 1190 | cds_lfht_alloc_bucket_table(ht, i); |
4105056a | 1191 | |
4105056a | 1192 | /* |
1ee8f000 LJ |
1193 | * Set all bucket nodes reverse hash values for a level and |
1194 | * link all bucket nodes into the table. | |
4105056a | 1195 | */ |
dc1da8f6 | 1196 | init_table_populate(ht, i, len); |
4105056a | 1197 | |
f9c80341 MD |
1198 | /* |
1199 | * Update table size. | |
1200 | */ | |
1201 | cmm_smp_wmb(); /* populate data before RCU size */ | |
4f6e90b7 | 1202 | CMM_STORE_SHARED(ht->t.size, 1UL << i); |
f9c80341 | 1203 | |
4f6e90b7 | 1204 | dbg_printf("init new size: %lu\n", 1UL << i); |
4105056a MD |
1205 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
1206 | break; | |
1207 | } | |
1208 | } | |
1209 | ||
e8de508e MD |
1210 | /* |
1211 | * Holding RCU read lock to protect _cds_lfht_remove against memory | |
1212 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
1213 | * problem). | |
1214 | * For a single level, we logically remove and garbage collect each node. | |
1215 | * | |
1216 | * As a design choice, we perform logical removal and garbage collection on a | |
1217 | * node-per-node basis to simplify this algorithm. We also assume keeping good | |
1218 | * cache locality of the operation would overweight possible performance gain | |
1219 | * that could be achieved by batching garbage collection for multiple levels. | |
1220 | * However, this would have to be justified by benchmarks. | |
1221 | * | |
1222 | * Concurrent removal and add operations are helping us perform garbage | |
1223 | * collection of logically removed nodes. We guarantee that all logically | |
1224 | * removed nodes have been garbage-collected (unlinked) before call_rcu is | |
1ee8f000 | 1225 | * invoked to free a hole level of bucket nodes (after a grace period). |
e8de508e MD |
1226 | * |
1227 | * Logical removal and garbage collection can therefore be done in batch or on a | |
1228 | * node-per-node basis, as long as the guarantee above holds. | |
9ee0fc9a | 1229 | * |
b7d619b0 MD |
1230 | * When we reach a certain length, we can split this removal over many worker |
1231 | * threads, based on the number of CPUs available in the system. This should | |
1232 | * take care of not letting resize process lag behind too many concurrent | |
9ee0fc9a | 1233 | * updater threads actively inserting into the hash table. |
e8de508e | 1234 | */ |
4105056a | 1235 | static |
b7d619b0 MD |
1236 | void remove_table_partition(struct cds_lfht *ht, unsigned long i, |
1237 | unsigned long start, unsigned long len) | |
4105056a | 1238 | { |
9d72a73f | 1239 | unsigned long j, size = 1UL << (i - 1); |
4105056a | 1240 | |
d0d8f9aa | 1241 | assert(i > MIN_TABLE_ORDER); |
4105056a | 1242 | ht->cds_lfht_rcu_read_lock(); |
9d72a73f LJ |
1243 | for (j = size + start; j < size + start + len; j++) { |
1244 | struct cds_lfht_node *fini_node = bucket_at(ht, j); | |
1245 | ||
1246 | assert(j >= size && j < (size << 1)); | |
1247 | dbg_printf("remove entry: order %lu index %lu hash %lu\n", | |
1248 | i, j, j); | |
1249 | fini_node->reverse_hash = bit_reverse_ulong(j); | |
1250 | (void) _cds_lfht_del(ht, size, fini_node, 1); | |
abc490a1 | 1251 | } |
4105056a | 1252 | ht->cds_lfht_rcu_read_unlock(); |
b7d619b0 MD |
1253 | } |
1254 | ||
1255 | static | |
1256 | void remove_table(struct cds_lfht *ht, unsigned long i, unsigned long len) | |
1257 | { | |
1258 | ||
1259 | assert(nr_cpus_mask != -1); | |
6083a889 | 1260 | if (nr_cpus_mask < 0 || len < 2 * MIN_PARTITION_PER_THREAD) { |
b7d619b0 MD |
1261 | ht->cds_lfht_rcu_thread_online(); |
1262 | remove_table_partition(ht, i, 0, len); | |
1263 | ht->cds_lfht_rcu_thread_offline(); | |
1264 | return; | |
1265 | } | |
1266 | partition_resize_helper(ht, i, len, remove_table_partition); | |
2ed95849 MD |
1267 | } |
1268 | ||
1475579c | 1269 | static |
4105056a | 1270 | void fini_table(struct cds_lfht *ht, |
93d46c39 | 1271 | unsigned long first_order, unsigned long last_order) |
1475579c | 1272 | { |
93d46c39 | 1273 | long i; |
48f1b16d | 1274 | unsigned long free_by_rcu_order = 0; |
1475579c | 1275 | |
93d46c39 LJ |
1276 | dbg_printf("fini 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 = last_order; i >= first_order; i--) { |
4105056a | 1280 | unsigned long len; |
1475579c | 1281 | |
4f6e90b7 | 1282 | len = 1UL << (i - 1); |
1475579c | 1283 | dbg_printf("fini order %lu len: %lu\n", i, len); |
4105056a | 1284 | |
4d676753 MD |
1285 | /* Stop shrink if the resize target changes under us */ |
1286 | if (CMM_LOAD_SHARED(ht->t.resize_target) > (1UL << (i - 1))) | |
1287 | break; | |
1288 | ||
1289 | cmm_smp_wmb(); /* populate data before RCU size */ | |
1290 | CMM_STORE_SHARED(ht->t.size, 1UL << (i - 1)); | |
1291 | ||
1292 | /* | |
1293 | * We need to wait for all add operations to reach Q.S. (and | |
1294 | * thus use the new table for lookups) before we can start | |
1ee8f000 | 1295 | * releasing the old bucket nodes. Otherwise their lookup will |
4d676753 MD |
1296 | * return a logically removed node as insert position. |
1297 | */ | |
1298 | ht->cds_lfht_synchronize_rcu(); | |
48f1b16d LJ |
1299 | if (free_by_rcu_order) |
1300 | cds_lfht_free_bucket_table(ht, free_by_rcu_order); | |
4d676753 | 1301 | |
21263e21 | 1302 | /* |
1ee8f000 LJ |
1303 | * Set "removed" flag in bucket nodes about to be removed. |
1304 | * Unlink all now-logically-removed bucket node pointers. | |
4105056a MD |
1305 | * Concurrent add/remove operation are helping us doing |
1306 | * the gc. | |
21263e21 | 1307 | */ |
4105056a MD |
1308 | remove_table(ht, i, len); |
1309 | ||
48f1b16d | 1310 | free_by_rcu_order = i; |
4105056a MD |
1311 | |
1312 | dbg_printf("fini new size: %lu\n", 1UL << i); | |
1475579c MD |
1313 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
1314 | break; | |
1315 | } | |
0d14ceb2 | 1316 | |
48f1b16d | 1317 | if (free_by_rcu_order) { |
0d14ceb2 | 1318 | ht->cds_lfht_synchronize_rcu(); |
48f1b16d | 1319 | cds_lfht_free_bucket_table(ht, free_by_rcu_order); |
0d14ceb2 | 1320 | } |
1475579c MD |
1321 | } |
1322 | ||
ff0d69de | 1323 | static |
1ee8f000 | 1324 | void cds_lfht_create_bucket(struct cds_lfht *ht, unsigned long size) |
ff0d69de | 1325 | { |
04db56f8 | 1326 | struct cds_lfht_node *prev, *node; |
9d72a73f | 1327 | unsigned long order, len, i; |
ff0d69de | 1328 | |
48f1b16d | 1329 | cds_lfht_alloc_bucket_table(ht, 0); |
ff0d69de | 1330 | |
9d72a73f LJ |
1331 | dbg_printf("create bucket: order 0 index 0 hash 0\n"); |
1332 | node = bucket_at(ht, 0); | |
1333 | node->next = flag_bucket(get_end()); | |
1334 | node->reverse_hash = 0; | |
ff0d69de LJ |
1335 | |
1336 | for (order = 1; order < get_count_order_ulong(size) + 1; order++) { | |
1337 | len = 1UL << (order - 1); | |
48f1b16d | 1338 | cds_lfht_alloc_bucket_table(ht, order); |
ff0d69de | 1339 | |
9d72a73f LJ |
1340 | for (i = 0; i < len; i++) { |
1341 | /* | |
1342 | * Now, we are trying to init the node with the | |
1343 | * hash=(len+i) (which is also a bucket with the | |
1344 | * index=(len+i)) and insert it into the hash table, | |
1345 | * so this node has to be inserted after the bucket | |
1346 | * with the index=(len+i)&(len-1)=i. And because there | |
1347 | * is no other non-bucket node nor bucket node with | |
1348 | * larger index/hash inserted, so the bucket node | |
1349 | * being inserted should be inserted directly linked | |
1350 | * after the bucket node with index=i. | |
1351 | */ | |
1352 | prev = bucket_at(ht, i); | |
1353 | node = bucket_at(ht, len + i); | |
ff0d69de | 1354 | |
1ee8f000 | 1355 | dbg_printf("create bucket: order %lu index %lu hash %lu\n", |
9d72a73f LJ |
1356 | order, len + i, len + i); |
1357 | node->reverse_hash = bit_reverse_ulong(len + i); | |
1358 | ||
1359 | /* insert after prev */ | |
1360 | assert(is_bucket(prev->next)); | |
ff0d69de | 1361 | node->next = prev->next; |
1ee8f000 | 1362 | prev->next = flag_bucket(node); |
ff0d69de LJ |
1363 | } |
1364 | } | |
1365 | } | |
1366 | ||
0422d92c | 1367 | struct cds_lfht *_cds_lfht_new(unsigned long init_size, |
0722081a | 1368 | unsigned long min_nr_alloc_buckets, |
747d725c | 1369 | unsigned long max_nr_buckets, |
b8af5011 | 1370 | int flags, |
14044b37 | 1371 | void (*cds_lfht_call_rcu)(struct rcu_head *head, |
1475579c | 1372 | void (*func)(struct rcu_head *head)), |
01dbfa62 MD |
1373 | void (*cds_lfht_synchronize_rcu)(void), |
1374 | void (*cds_lfht_rcu_read_lock)(void), | |
5f511391 MD |
1375 | void (*cds_lfht_rcu_read_unlock)(void), |
1376 | void (*cds_lfht_rcu_thread_offline)(void), | |
b7d619b0 MD |
1377 | void (*cds_lfht_rcu_thread_online)(void), |
1378 | void (*cds_lfht_rcu_register_thread)(void), | |
1379 | void (*cds_lfht_rcu_unregister_thread)(void), | |
1380 | pthread_attr_t *attr) | |
abc490a1 | 1381 | { |
14044b37 | 1382 | struct cds_lfht *ht; |
24365af7 | 1383 | unsigned long order; |
abc490a1 | 1384 | |
0722081a LJ |
1385 | /* min_nr_alloc_buckets must be power of two */ |
1386 | if (!min_nr_alloc_buckets || (min_nr_alloc_buckets & (min_nr_alloc_buckets - 1))) | |
5488222b | 1387 | return NULL; |
747d725c | 1388 | |
8129be4e | 1389 | /* init_size must be power of two */ |
5488222b | 1390 | if (!init_size || (init_size & (init_size - 1))) |
8129be4e | 1391 | return NULL; |
747d725c LJ |
1392 | |
1393 | if (!max_nr_buckets) | |
1394 | max_nr_buckets = 1UL << (MAX_TABLE_ORDER - 1); | |
1395 | ||
1396 | /* max_nr_buckets must be power of two */ | |
1397 | if (!max_nr_buckets || (max_nr_buckets & (max_nr_buckets - 1))) | |
1398 | return NULL; | |
1399 | ||
0722081a | 1400 | min_nr_alloc_buckets = max(min_nr_alloc_buckets, MIN_TABLE_SIZE); |
d0d8f9aa | 1401 | init_size = max(init_size, MIN_TABLE_SIZE); |
747d725c LJ |
1402 | max_nr_buckets = max(max_nr_buckets, min_nr_alloc_buckets); |
1403 | init_size = min(init_size, max_nr_buckets); | |
14044b37 | 1404 | ht = calloc(1, sizeof(struct cds_lfht)); |
b7d619b0 | 1405 | assert(ht); |
b5d6b20f | 1406 | ht->flags = flags; |
14044b37 | 1407 | ht->cds_lfht_call_rcu = cds_lfht_call_rcu; |
1475579c | 1408 | ht->cds_lfht_synchronize_rcu = cds_lfht_synchronize_rcu; |
01dbfa62 MD |
1409 | ht->cds_lfht_rcu_read_lock = cds_lfht_rcu_read_lock; |
1410 | ht->cds_lfht_rcu_read_unlock = cds_lfht_rcu_read_unlock; | |
5f511391 MD |
1411 | ht->cds_lfht_rcu_thread_offline = cds_lfht_rcu_thread_offline; |
1412 | ht->cds_lfht_rcu_thread_online = cds_lfht_rcu_thread_online; | |
b7d619b0 MD |
1413 | ht->cds_lfht_rcu_register_thread = cds_lfht_rcu_register_thread; |
1414 | ht->cds_lfht_rcu_unregister_thread = cds_lfht_rcu_unregister_thread; | |
1415 | ht->resize_attr = attr; | |
5afadd12 | 1416 | alloc_split_items_count(ht); |
abc490a1 MD |
1417 | /* this mutex should not nest in read-side C.S. */ |
1418 | pthread_mutex_init(&ht->resize_mutex, NULL); | |
5488222b | 1419 | order = get_count_order_ulong(init_size); |
93d46c39 | 1420 | ht->t.resize_target = 1UL << order; |
0722081a LJ |
1421 | ht->min_nr_alloc_buckets = min_nr_alloc_buckets; |
1422 | ht->min_alloc_buckets_order = get_count_order_ulong(min_nr_alloc_buckets); | |
747d725c | 1423 | ht->max_nr_buckets = max_nr_buckets; |
1ee8f000 | 1424 | cds_lfht_create_bucket(ht, 1UL << order); |
bcbd36fc | 1425 | ht->t.size = 1UL << order; |
abc490a1 MD |
1426 | return ht; |
1427 | } | |
1428 | ||
6f554439 | 1429 | void cds_lfht_lookup(struct cds_lfht *ht, unsigned long hash, |
996ff57c | 1430 | cds_lfht_match_fct match, const void *key, |
6f554439 | 1431 | struct cds_lfht_iter *iter) |
2ed95849 | 1432 | { |
04db56f8 | 1433 | struct cds_lfht_node *node, *next, *bucket; |
0422d92c | 1434 | unsigned long reverse_hash, size; |
2ed95849 | 1435 | |
abc490a1 | 1436 | reverse_hash = bit_reverse_ulong(hash); |
464a1ec9 | 1437 | |
4105056a | 1438 | size = rcu_dereference(ht->t.size); |
04db56f8 | 1439 | bucket = lookup_bucket(ht, size, hash); |
1ee8f000 | 1440 | /* We can always skip the bucket node initially */ |
04db56f8 | 1441 | node = rcu_dereference(bucket->next); |
bb7b2f26 | 1442 | node = clear_flag(node); |
2ed95849 | 1443 | for (;;) { |
8ed51e04 | 1444 | if (caa_unlikely(is_end(node))) { |
96ad1112 | 1445 | node = next = NULL; |
abc490a1 | 1446 | break; |
bb7b2f26 | 1447 | } |
04db56f8 | 1448 | if (caa_unlikely(node->reverse_hash > reverse_hash)) { |
96ad1112 | 1449 | node = next = NULL; |
abc490a1 | 1450 | break; |
2ed95849 | 1451 | } |
04db56f8 | 1452 | next = rcu_dereference(node->next); |
7f52427b | 1453 | assert(node == clear_flag(node)); |
8ed51e04 | 1454 | if (caa_likely(!is_removed(next)) |
1ee8f000 | 1455 | && !is_bucket(next) |
04db56f8 | 1456 | && node->reverse_hash == reverse_hash |
0422d92c | 1457 | && caa_likely(match(node, key))) { |
273399de | 1458 | break; |
2ed95849 | 1459 | } |
1b81fe1a | 1460 | node = clear_flag(next); |
2ed95849 | 1461 | } |
1ee8f000 | 1462 | assert(!node || !is_bucket(rcu_dereference(node->next))); |
adc0de68 MD |
1463 | iter->node = node; |
1464 | iter->next = next; | |
abc490a1 | 1465 | } |
e0ba718a | 1466 | |
0422d92c | 1467 | void cds_lfht_next_duplicate(struct cds_lfht *ht, cds_lfht_match_fct match, |
996ff57c | 1468 | const void *key, struct cds_lfht_iter *iter) |
a481e5ff | 1469 | { |
adc0de68 | 1470 | struct cds_lfht_node *node, *next; |
a481e5ff | 1471 | unsigned long reverse_hash; |
a481e5ff | 1472 | |
adc0de68 | 1473 | node = iter->node; |
04db56f8 | 1474 | reverse_hash = node->reverse_hash; |
adc0de68 | 1475 | next = iter->next; |
a481e5ff MD |
1476 | node = clear_flag(next); |
1477 | ||
1478 | for (;;) { | |
8ed51e04 | 1479 | if (caa_unlikely(is_end(node))) { |
96ad1112 | 1480 | node = next = NULL; |
a481e5ff | 1481 | break; |
bb7b2f26 | 1482 | } |
04db56f8 | 1483 | if (caa_unlikely(node->reverse_hash > reverse_hash)) { |
96ad1112 | 1484 | node = next = NULL; |
a481e5ff MD |
1485 | break; |
1486 | } | |
04db56f8 | 1487 | next = rcu_dereference(node->next); |
8ed51e04 | 1488 | if (caa_likely(!is_removed(next)) |
1ee8f000 | 1489 | && !is_bucket(next) |
04db56f8 | 1490 | && caa_likely(match(node, key))) { |
a481e5ff MD |
1491 | break; |
1492 | } | |
1493 | node = clear_flag(next); | |
1494 | } | |
1ee8f000 | 1495 | assert(!node || !is_bucket(rcu_dereference(node->next))); |
adc0de68 MD |
1496 | iter->node = node; |
1497 | iter->next = next; | |
a481e5ff MD |
1498 | } |
1499 | ||
4e9b9fbf MD |
1500 | void cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_iter *iter) |
1501 | { | |
1502 | struct cds_lfht_node *node, *next; | |
1503 | ||
853395e1 | 1504 | node = clear_flag(iter->next); |
4e9b9fbf | 1505 | for (;;) { |
8ed51e04 | 1506 | if (caa_unlikely(is_end(node))) { |
4e9b9fbf MD |
1507 | node = next = NULL; |
1508 | break; | |
1509 | } | |
04db56f8 | 1510 | next = rcu_dereference(node->next); |
8ed51e04 | 1511 | if (caa_likely(!is_removed(next)) |
1ee8f000 | 1512 | && !is_bucket(next)) { |
4e9b9fbf MD |
1513 | break; |
1514 | } | |
1515 | node = clear_flag(next); | |
1516 | } | |
1ee8f000 | 1517 | assert(!node || !is_bucket(rcu_dereference(node->next))); |
4e9b9fbf MD |
1518 | iter->node = node; |
1519 | iter->next = next; | |
1520 | } | |
1521 | ||
1522 | void cds_lfht_first(struct cds_lfht *ht, struct cds_lfht_iter *iter) | |
1523 | { | |
4e9b9fbf | 1524 | /* |
1ee8f000 | 1525 | * Get next after first bucket node. The first bucket node is the |
4e9b9fbf MD |
1526 | * first node of the linked list. |
1527 | */ | |
9d72a73f | 1528 | iter->next = bucket_at(ht, 0)->next; |
4e9b9fbf MD |
1529 | cds_lfht_next(ht, iter); |
1530 | } | |
1531 | ||
0422d92c MD |
1532 | void cds_lfht_add(struct cds_lfht *ht, unsigned long hash, |
1533 | struct cds_lfht_node *node) | |
abc490a1 | 1534 | { |
0422d92c | 1535 | unsigned long size; |
ab7d5fc6 | 1536 | |
04db56f8 | 1537 | node->reverse_hash = bit_reverse_ulong((unsigned long) hash); |
4105056a | 1538 | size = rcu_dereference(ht->t.size); |
04db56f8 | 1539 | _cds_lfht_add(ht, NULL, NULL, size, node, NULL, 0); |
14360f1c | 1540 | ht_count_add(ht, size, hash); |
3eca1b8c MD |
1541 | } |
1542 | ||
14044b37 | 1543 | struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, |
6f554439 | 1544 | unsigned long hash, |
0422d92c | 1545 | cds_lfht_match_fct match, |
996ff57c | 1546 | const void *key, |
48ed1c18 | 1547 | struct cds_lfht_node *node) |
3eca1b8c | 1548 | { |
0422d92c | 1549 | unsigned long size; |
83beee94 | 1550 | struct cds_lfht_iter iter; |
3eca1b8c | 1551 | |
04db56f8 | 1552 | node->reverse_hash = bit_reverse_ulong((unsigned long) hash); |
4105056a | 1553 | size = rcu_dereference(ht->t.size); |
04db56f8 | 1554 | _cds_lfht_add(ht, match, key, size, node, &iter, 0); |
83beee94 | 1555 | if (iter.node == node) |
14360f1c | 1556 | ht_count_add(ht, size, hash); |
83beee94 | 1557 | return iter.node; |
2ed95849 MD |
1558 | } |
1559 | ||
9357c415 | 1560 | struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht, |
6f554439 | 1561 | unsigned long hash, |
0422d92c | 1562 | cds_lfht_match_fct match, |
996ff57c | 1563 | const void *key, |
48ed1c18 MD |
1564 | struct cds_lfht_node *node) |
1565 | { | |
0422d92c | 1566 | unsigned long size; |
83beee94 | 1567 | struct cds_lfht_iter iter; |
48ed1c18 | 1568 | |
04db56f8 | 1569 | node->reverse_hash = bit_reverse_ulong((unsigned long) hash); |
48ed1c18 | 1570 | size = rcu_dereference(ht->t.size); |
83beee94 | 1571 | for (;;) { |
04db56f8 | 1572 | _cds_lfht_add(ht, match, key, size, node, &iter, 0); |
83beee94 | 1573 | if (iter.node == node) { |
14360f1c | 1574 | ht_count_add(ht, size, hash); |
83beee94 MD |
1575 | return NULL; |
1576 | } | |
1577 | ||
1578 | if (!_cds_lfht_replace(ht, size, iter.node, iter.next, node)) | |
1579 | return iter.node; | |
1580 | } | |
48ed1c18 MD |
1581 | } |
1582 | ||
9357c415 MD |
1583 | int cds_lfht_replace(struct cds_lfht *ht, struct cds_lfht_iter *old_iter, |
1584 | struct cds_lfht_node *new_node) | |
1585 | { | |
1586 | unsigned long size; | |
1587 | ||
1588 | size = rcu_dereference(ht->t.size); | |
1589 | return _cds_lfht_replace(ht, size, old_iter->node, old_iter->next, | |
1590 | new_node); | |
1591 | } | |
1592 | ||
1593 | int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_iter *iter) | |
2ed95849 | 1594 | { |
14360f1c | 1595 | unsigned long size, hash; |
df44348d | 1596 | int ret; |
abc490a1 | 1597 | |
4105056a | 1598 | size = rcu_dereference(ht->t.size); |
9357c415 | 1599 | ret = _cds_lfht_del(ht, size, iter->node, 0); |
14360f1c | 1600 | if (!ret) { |
04db56f8 | 1601 | hash = bit_reverse_ulong(iter->node->reverse_hash); |
14360f1c LJ |
1602 | ht_count_del(ht, size, hash); |
1603 | } | |
df44348d | 1604 | return ret; |
2ed95849 | 1605 | } |
ab7d5fc6 | 1606 | |
abc490a1 | 1607 | static |
1ee8f000 | 1608 | int cds_lfht_delete_bucket(struct cds_lfht *ht) |
674f7a69 | 1609 | { |
14044b37 | 1610 | struct cds_lfht_node *node; |
4105056a | 1611 | unsigned long order, i, size; |
674f7a69 | 1612 | |
abc490a1 | 1613 | /* Check that the table is empty */ |
9d72a73f | 1614 | node = bucket_at(ht, 0); |
abc490a1 | 1615 | do { |
04db56f8 | 1616 | node = clear_flag(node)->next; |
1ee8f000 | 1617 | if (!is_bucket(node)) |
abc490a1 | 1618 | return -EPERM; |
273399de | 1619 | assert(!is_removed(node)); |
bb7b2f26 | 1620 | } while (!is_end(node)); |
4105056a MD |
1621 | /* |
1622 | * size accessed without rcu_dereference because hash table is | |
1623 | * being destroyed. | |
1624 | */ | |
1625 | size = ht->t.size; | |
1ee8f000 | 1626 | /* Internal sanity check: all nodes left should be bucket */ |
48f1b16d LJ |
1627 | for (i = 0; i < size; i++) { |
1628 | node = bucket_at(ht, i); | |
1629 | dbg_printf("delete bucket: index %lu expected hash %lu hash %lu\n", | |
1630 | i, i, bit_reverse_ulong(node->reverse_hash)); | |
1631 | assert(is_bucket(node->next)); | |
1632 | } | |
24365af7 | 1633 | |
48f1b16d LJ |
1634 | for (order = get_count_order_ulong(size); (long)order >= 0; order--) |
1635 | cds_lfht_free_bucket_table(ht, order); | |
5488222b | 1636 | |
abc490a1 | 1637 | return 0; |
674f7a69 MD |
1638 | } |
1639 | ||
1640 | /* | |
1641 | * Should only be called when no more concurrent readers nor writers can | |
1642 | * possibly access the table. | |
1643 | */ | |
b7d619b0 | 1644 | int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr) |
674f7a69 | 1645 | { |
5e28c532 MD |
1646 | int ret; |
1647 | ||
848d4088 | 1648 | /* Wait for in-flight resize operations to complete */ |
24953e08 MD |
1649 | _CMM_STORE_SHARED(ht->in_progress_destroy, 1); |
1650 | cmm_smp_mb(); /* Store destroy before load resize */ | |
848d4088 MD |
1651 | while (uatomic_read(&ht->in_progress_resize)) |
1652 | poll(NULL, 0, 100); /* wait for 100ms */ | |
1ee8f000 | 1653 | ret = cds_lfht_delete_bucket(ht); |
abc490a1 MD |
1654 | if (ret) |
1655 | return ret; | |
5afadd12 | 1656 | free_split_items_count(ht); |
b7d619b0 MD |
1657 | if (attr) |
1658 | *attr = ht->resize_attr; | |
98808fb1 | 1659 | poison_free(ht); |
5e28c532 | 1660 | return ret; |
674f7a69 MD |
1661 | } |
1662 | ||
14044b37 | 1663 | void cds_lfht_count_nodes(struct cds_lfht *ht, |
d933dd0e | 1664 | long *approx_before, |
273399de | 1665 | unsigned long *count, |
973e5e1b | 1666 | unsigned long *removed, |
d933dd0e | 1667 | long *approx_after) |
273399de | 1668 | { |
14044b37 | 1669 | struct cds_lfht_node *node, *next; |
1ee8f000 | 1670 | unsigned long nr_bucket = 0; |
273399de | 1671 | |
7ed7682f | 1672 | *approx_before = 0; |
5afadd12 | 1673 | if (ht->split_count) { |
973e5e1b MD |
1674 | int i; |
1675 | ||
4c42f1b8 LJ |
1676 | for (i = 0; i < split_count_mask + 1; i++) { |
1677 | *approx_before += uatomic_read(&ht->split_count[i].add); | |
1678 | *approx_before -= uatomic_read(&ht->split_count[i].del); | |
973e5e1b MD |
1679 | } |
1680 | } | |
1681 | ||
273399de MD |
1682 | *count = 0; |
1683 | *removed = 0; | |
1684 | ||
1ee8f000 | 1685 | /* Count non-bucket nodes in the table */ |
9d72a73f | 1686 | node = bucket_at(ht, 0); |
273399de | 1687 | do { |
04db56f8 | 1688 | next = rcu_dereference(node->next); |
b198f0fd | 1689 | if (is_removed(next)) { |
1ee8f000 | 1690 | if (!is_bucket(next)) |
973e5e1b MD |
1691 | (*removed)++; |
1692 | else | |
1ee8f000 LJ |
1693 | (nr_bucket)++; |
1694 | } else if (!is_bucket(next)) | |
273399de | 1695 | (*count)++; |
24365af7 | 1696 | else |
1ee8f000 | 1697 | (nr_bucket)++; |
273399de | 1698 | node = clear_flag(next); |
bb7b2f26 | 1699 | } while (!is_end(node)); |
1ee8f000 | 1700 | dbg_printf("number of bucket nodes: %lu\n", nr_bucket); |
7ed7682f | 1701 | *approx_after = 0; |
5afadd12 | 1702 | if (ht->split_count) { |
973e5e1b MD |
1703 | int i; |
1704 | ||
4c42f1b8 LJ |
1705 | for (i = 0; i < split_count_mask + 1; i++) { |
1706 | *approx_after += uatomic_read(&ht->split_count[i].add); | |
1707 | *approx_after -= uatomic_read(&ht->split_count[i].del); | |
973e5e1b MD |
1708 | } |
1709 | } | |
273399de MD |
1710 | } |
1711 | ||
1475579c | 1712 | /* called with resize mutex held */ |
abc490a1 | 1713 | static |
4105056a | 1714 | void _do_cds_lfht_grow(struct cds_lfht *ht, |
1475579c | 1715 | unsigned long old_size, unsigned long new_size) |
abc490a1 | 1716 | { |
1475579c | 1717 | unsigned long old_order, new_order; |
1475579c | 1718 | |
93d46c39 LJ |
1719 | old_order = get_count_order_ulong(old_size); |
1720 | new_order = get_count_order_ulong(new_size); | |
1a401918 LJ |
1721 | dbg_printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", |
1722 | old_size, old_order, new_size, new_order); | |
1475579c | 1723 | assert(new_size > old_size); |
93d46c39 | 1724 | init_table(ht, old_order + 1, new_order); |
abc490a1 MD |
1725 | } |
1726 | ||
1727 | /* called with resize mutex held */ | |
1728 | static | |
4105056a | 1729 | void _do_cds_lfht_shrink(struct cds_lfht *ht, |
1475579c | 1730 | unsigned long old_size, unsigned long new_size) |
464a1ec9 | 1731 | { |
1475579c | 1732 | unsigned long old_order, new_order; |
464a1ec9 | 1733 | |
d0d8f9aa | 1734 | new_size = max(new_size, MIN_TABLE_SIZE); |
93d46c39 LJ |
1735 | old_order = get_count_order_ulong(old_size); |
1736 | new_order = get_count_order_ulong(new_size); | |
1a401918 LJ |
1737 | dbg_printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", |
1738 | old_size, old_order, new_size, new_order); | |
1475579c | 1739 | assert(new_size < old_size); |
1475579c | 1740 | |
1ee8f000 | 1741 | /* Remove and unlink all bucket nodes to remove. */ |
93d46c39 | 1742 | fini_table(ht, new_order + 1, old_order); |
464a1ec9 MD |
1743 | } |
1744 | ||
1475579c MD |
1745 | |
1746 | /* called with resize mutex held */ | |
1747 | static | |
1748 | void _do_cds_lfht_resize(struct cds_lfht *ht) | |
1749 | { | |
1750 | unsigned long new_size, old_size; | |
4105056a MD |
1751 | |
1752 | /* | |
1753 | * Resize table, re-do if the target size has changed under us. | |
1754 | */ | |
1755 | do { | |
d2be3620 MD |
1756 | assert(uatomic_read(&ht->in_progress_resize)); |
1757 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
1758 | break; | |
4105056a MD |
1759 | ht->t.resize_initiated = 1; |
1760 | old_size = ht->t.size; | |
1761 | new_size = CMM_LOAD_SHARED(ht->t.resize_target); | |
1762 | if (old_size < new_size) | |
1763 | _do_cds_lfht_grow(ht, old_size, new_size); | |
1764 | else if (old_size > new_size) | |
1765 | _do_cds_lfht_shrink(ht, old_size, new_size); | |
1766 | ht->t.resize_initiated = 0; | |
1767 | /* write resize_initiated before read resize_target */ | |
1768 | cmm_smp_mb(); | |
4d676753 | 1769 | } while (ht->t.size != CMM_LOAD_SHARED(ht->t.resize_target)); |
1475579c MD |
1770 | } |
1771 | ||
abc490a1 | 1772 | static |
ab65b890 | 1773 | unsigned long resize_target_grow(struct cds_lfht *ht, unsigned long new_size) |
464a1ec9 | 1774 | { |
ab65b890 | 1775 | return _uatomic_xchg_monotonic_increase(&ht->t.resize_target, new_size); |
464a1ec9 MD |
1776 | } |
1777 | ||
1475579c | 1778 | static |
4105056a | 1779 | void resize_target_update_count(struct cds_lfht *ht, |
b8af5011 | 1780 | unsigned long count) |
1475579c | 1781 | { |
d0d8f9aa | 1782 | count = max(count, MIN_TABLE_SIZE); |
747d725c | 1783 | count = min(count, ht->max_nr_buckets); |
4105056a | 1784 | uatomic_set(&ht->t.resize_target, count); |
1475579c MD |
1785 | } |
1786 | ||
1787 | void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size) | |
464a1ec9 | 1788 | { |
4105056a MD |
1789 | resize_target_update_count(ht, new_size); |
1790 | CMM_STORE_SHARED(ht->t.resize_initiated, 1); | |
5f511391 | 1791 | ht->cds_lfht_rcu_thread_offline(); |
1475579c MD |
1792 | pthread_mutex_lock(&ht->resize_mutex); |
1793 | _do_cds_lfht_resize(ht); | |
1794 | pthread_mutex_unlock(&ht->resize_mutex); | |
5f511391 | 1795 | ht->cds_lfht_rcu_thread_online(); |
abc490a1 | 1796 | } |
464a1ec9 | 1797 | |
abc490a1 MD |
1798 | static |
1799 | void do_resize_cb(struct rcu_head *head) | |
1800 | { | |
1801 | struct rcu_resize_work *work = | |
1802 | caa_container_of(head, struct rcu_resize_work, head); | |
14044b37 | 1803 | struct cds_lfht *ht = work->ht; |
abc490a1 | 1804 | |
5f511391 | 1805 | ht->cds_lfht_rcu_thread_offline(); |
abc490a1 | 1806 | pthread_mutex_lock(&ht->resize_mutex); |
14044b37 | 1807 | _do_cds_lfht_resize(ht); |
abc490a1 | 1808 | pthread_mutex_unlock(&ht->resize_mutex); |
5f511391 | 1809 | ht->cds_lfht_rcu_thread_online(); |
98808fb1 | 1810 | poison_free(work); |
848d4088 MD |
1811 | cmm_smp_mb(); /* finish resize before decrement */ |
1812 | uatomic_dec(&ht->in_progress_resize); | |
464a1ec9 MD |
1813 | } |
1814 | ||
abc490a1 | 1815 | static |
f1f119ee | 1816 | void __cds_lfht_resize_lazy_launch(struct cds_lfht *ht) |
ab7d5fc6 | 1817 | { |
abc490a1 MD |
1818 | struct rcu_resize_work *work; |
1819 | ||
4105056a MD |
1820 | /* Store resize_target before read resize_initiated */ |
1821 | cmm_smp_mb(); | |
ab65b890 | 1822 | if (!CMM_LOAD_SHARED(ht->t.resize_initiated)) { |
848d4088 | 1823 | uatomic_inc(&ht->in_progress_resize); |
59290e9d | 1824 | cmm_smp_mb(); /* increment resize count before load destroy */ |
ed35e6d8 MD |
1825 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) { |
1826 | uatomic_dec(&ht->in_progress_resize); | |
59290e9d | 1827 | return; |
ed35e6d8 | 1828 | } |
f9830efd MD |
1829 | work = malloc(sizeof(*work)); |
1830 | work->ht = ht; | |
14044b37 | 1831 | ht->cds_lfht_call_rcu(&work->head, do_resize_cb); |
4105056a | 1832 | CMM_STORE_SHARED(ht->t.resize_initiated, 1); |
f9830efd | 1833 | } |
ab7d5fc6 | 1834 | } |
3171717f | 1835 | |
f1f119ee LJ |
1836 | static |
1837 | void cds_lfht_resize_lazy_grow(struct cds_lfht *ht, unsigned long size, int growth) | |
1838 | { | |
1839 | unsigned long target_size = size << growth; | |
1840 | ||
747d725c | 1841 | target_size = min(target_size, ht->max_nr_buckets); |
f1f119ee LJ |
1842 | if (resize_target_grow(ht, target_size) >= target_size) |
1843 | return; | |
1844 | ||
1845 | __cds_lfht_resize_lazy_launch(ht); | |
1846 | } | |
1847 | ||
89bb121d LJ |
1848 | /* |
1849 | * We favor grow operations over shrink. A shrink operation never occurs | |
1850 | * if a grow operation is queued for lazy execution. A grow operation | |
1851 | * cancels any pending shrink lazy execution. | |
1852 | */ | |
3171717f | 1853 | static |
4105056a | 1854 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, |
3171717f MD |
1855 | unsigned long count) |
1856 | { | |
b8af5011 MD |
1857 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) |
1858 | return; | |
d0d8f9aa | 1859 | count = max(count, MIN_TABLE_SIZE); |
747d725c | 1860 | count = min(count, ht->max_nr_buckets); |
89bb121d LJ |
1861 | if (count == size) |
1862 | return; /* Already the right size, no resize needed */ | |
1863 | if (count > size) { /* lazy grow */ | |
1864 | if (resize_target_grow(ht, count) >= count) | |
1865 | return; | |
1866 | } else { /* lazy shrink */ | |
1867 | for (;;) { | |
1868 | unsigned long s; | |
1869 | ||
1870 | s = uatomic_cmpxchg(&ht->t.resize_target, size, count); | |
1871 | if (s == size) | |
1872 | break; /* no resize needed */ | |
1873 | if (s > size) | |
1874 | return; /* growing is/(was just) in progress */ | |
1875 | if (s <= count) | |
1876 | return; /* some other thread do shrink */ | |
1877 | size = s; | |
1878 | } | |
1879 | } | |
f1f119ee | 1880 | __cds_lfht_resize_lazy_launch(ht); |
3171717f | 1881 | } |