Commit | Line | Data |
---|---|---|
5e28c532 | 1 | /* |
abc490a1 MD |
2 | * rculfhash.c |
3 | * | |
4 | * Userspace RCU library - Lock-Free Expandable RCU Hash Table | |
5 | * | |
6 | * Copyright 2010-2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
7 | * | |
8 | * This library is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU Lesser General Public | |
10 | * License as published by the Free Software Foundation; either | |
11 | * version 2.1 of the License, or (at your option) any later version. | |
12 | * | |
13 | * This library is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | * Lesser General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU Lesser General Public | |
19 | * License along with this library; if not, write to the Free Software | |
20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
5e28c532 MD |
21 | */ |
22 | ||
e753ff5a MD |
23 | /* |
24 | * Based on the following articles: | |
25 | * - Ori Shalev and Nir Shavit. Split-ordered lists: Lock-free | |
26 | * extensible hash tables. J. ACM 53, 3 (May 2006), 379-405. | |
27 | * - Michael, M. M. High performance dynamic lock-free hash tables | |
28 | * and list-based sets. In Proceedings of the fourteenth annual ACM | |
29 | * symposium on Parallel algorithms and architectures, ACM Press, | |
30 | * (2002), 73-82. | |
31 | * | |
32 | * Some specificities of this Lock-Free Expandable RCU Hash Table | |
33 | * implementation: | |
34 | * | |
35 | * - RCU read-side critical section allows readers to perform hash | |
36 | * table lookups and use the returned objects safely by delaying | |
37 | * memory reclaim of a grace period. | |
38 | * - Add and remove operations are lock-free, and do not need to | |
39 | * allocate memory. They need to be executed within RCU read-side | |
40 | * critical section to ensure the objects they read are valid and to | |
41 | * deal with the cmpxchg ABA problem. | |
42 | * - add and add_unique operations are supported. add_unique checks if | |
43 | * the node key already exists in the hash table. It ensures no key | |
44 | * duplicata exists. | |
45 | * - The resize operation executes concurrently with add/remove/lookup. | |
46 | * - Hash table nodes are contained within a split-ordered list. This | |
47 | * list is ordered by incrementing reversed-bits-hash value. | |
48 | * - An index of dummy nodes is kept. These dummy nodes are the hash | |
49 | * table "buckets", and they are also chained together in the | |
50 | * split-ordered list, which allows recursive expansion. | |
51 | * - The resize operation only allows expanding the hash table. | |
52 | * It is triggered either through an API call or automatically by | |
53 | * detecting long chains in the add operation. | |
54 | * - Resize operation initiated by long chain detection is executed by a | |
55 | * call_rcu thread, which keeps lock-freedom of add and remove. | |
56 | * - Resize operations are protected by a mutex. | |
57 | * - The removal operation is split in two parts: first, a "removed" | |
58 | * flag is set in the next pointer within the node to remove. Then, | |
59 | * a "garbage collection" is performed in the bucket containing the | |
60 | * removed node (from the start of the bucket up to the removed node). | |
61 | * All encountered nodes with "removed" flag set in their next | |
62 | * pointers are removed from the linked-list. If the cmpxchg used for | |
63 | * removal fails (due to concurrent garbage-collection or concurrent | |
64 | * add), we retry from the beginning of the bucket. This ensures that | |
65 | * the node with "removed" flag set is removed from the hash table | |
66 | * (not visible to lookups anymore) before the RCU read-side critical | |
67 | * section held across removal ends. Furthermore, this ensures that | |
68 | * the node with "removed" flag set is removed from the linked-list | |
69 | * before its memory is reclaimed. Only the thread which removal | |
70 | * successfully set the "removed" flag (with a cmpxchg) into a node's | |
71 | * next pointer is considered to have succeeded its removal (and thus | |
72 | * owns the node to reclaim). Because we garbage-collect starting from | |
73 | * an invariant node (the start-of-bucket dummy node) up to the | |
74 | * "removed" node (or find a reverse-hash that is higher), we are sure | |
75 | * that a successful traversal of the chain leads to a chain that is | |
76 | * present in the linked-list (the start node is never removed) and | |
77 | * that is does not contain the "removed" node anymore, even if | |
78 | * concurrent delete/add operations are changing the structure of the | |
79 | * list concurrently. | |
29e669f6 MD |
80 | * - The add operation performs gargage collection of buckets if it |
81 | * encounters nodes with removed flag set in the bucket where it wants | |
82 | * to add its new node. This ensures lock-freedom of add operation by | |
83 | * helping the remover unlink nodes from the list rather than to wait | |
84 | * for it do to so. | |
e753ff5a MD |
85 | * - A RCU "order table" indexed by log2(hash index) is copied and |
86 | * expanded by the resize operation. This order table allows finding | |
87 | * the "dummy node" tables. | |
88 | * - There is one dummy node table per hash index order. The size of | |
89 | * each dummy node table is half the number of hashes contained in | |
90 | * this order. | |
91 | * - call_rcu is used to garbage-collect the old order table. | |
92 | * - The per-order dummy node tables contain a compact version of the | |
93 | * hash table nodes. These tables are invariant after they are | |
94 | * populated into the hash table. | |
95 | */ | |
96 | ||
2ed95849 MD |
97 | #define _LGPL_SOURCE |
98 | #include <stdlib.h> | |
e0ba718a MD |
99 | #include <errno.h> |
100 | #include <assert.h> | |
101 | #include <stdio.h> | |
abc490a1 | 102 | #include <stdint.h> |
f000907d | 103 | #include <string.h> |
e0ba718a | 104 | |
df44348d | 105 | #include "config.h" |
2ed95849 | 106 | #include <urcu.h> |
abc490a1 | 107 | #include <urcu-call-rcu.h> |
a42cc659 MD |
108 | #include <urcu/arch.h> |
109 | #include <urcu/uatomic.h> | |
674f7a69 | 110 | #include <urcu/jhash.h> |
a42cc659 | 111 | #include <urcu/compiler.h> |
abc490a1 | 112 | #include <urcu/rculfhash.h> |
5e28c532 | 113 | #include <stdio.h> |
464a1ec9 | 114 | #include <pthread.h> |
44395fb7 | 115 | |
f9830efd | 116 | #ifdef DEBUG |
f0c29ed7 | 117 | #define dbg_printf(fmt, args...) printf("[debug rculfhash] " fmt, ## args) |
f9830efd | 118 | #else |
e753ff5a | 119 | #define dbg_printf(fmt, args...) |
f9830efd MD |
120 | #endif |
121 | ||
01370f0b MD |
122 | #define CHAIN_LEN_TARGET 4 |
123 | #define CHAIN_LEN_RESIZE_THRESHOLD 8 | |
2ed95849 | 124 | |
df44348d MD |
125 | /* Commit counter changes to global counter each 1024 steps */ |
126 | #define COUNT_COMMIT_ORDER 10 | |
127 | ||
abc490a1 MD |
128 | #ifndef max |
129 | #define max(a, b) ((a) > (b) ? (a) : (b)) | |
130 | #endif | |
2ed95849 | 131 | |
d95bd160 MD |
132 | /* |
133 | * The removed flag needs to be updated atomically with the pointer. | |
134 | * The dummy flag does not require to be updated atomically with the | |
135 | * pointer, but it is added as a pointer low bit flag to save space. | |
136 | */ | |
d37166c6 | 137 | #define REMOVED_FLAG (1UL << 0) |
f5596c94 MD |
138 | #define DUMMY_FLAG (1UL << 1) |
139 | #define FLAGS_MASK ((1UL << 2) - 1) | |
d37166c6 | 140 | |
df44348d MD |
141 | struct ht_items_count { |
142 | unsigned long v; | |
143 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); | |
144 | ||
395270b6 | 145 | struct rcu_table { |
abc490a1 | 146 | unsigned long size; /* always a power of 2 */ |
f9830efd | 147 | unsigned long resize_target; |
11519af6 | 148 | int resize_initiated; |
abc490a1 | 149 | struct rcu_head head; |
14044b37 | 150 | struct _cds_lfht_node *tbl[0]; |
395270b6 MD |
151 | }; |
152 | ||
14044b37 | 153 | struct cds_lfht { |
395270b6 | 154 | struct rcu_table *t; /* shared */ |
14044b37 MD |
155 | cds_lfht_hash_fct hash_fct; |
156 | cds_lfht_compare_fct compare_fct; | |
732ad076 | 157 | unsigned long hash_seed; |
464a1ec9 | 158 | pthread_mutex_t resize_mutex; /* resize mutex: add/del mutex */ |
33c7c748 | 159 | unsigned int in_progress_resize, in_progress_destroy; |
14044b37 | 160 | void (*cds_lfht_call_rcu)(struct rcu_head *head, |
abc490a1 | 161 | void (*func)(struct rcu_head *head)); |
df44348d MD |
162 | unsigned long count; /* global approximate item count */ |
163 | struct ht_items_count *percpu_count; /* per-cpu item count */ | |
2ed95849 MD |
164 | }; |
165 | ||
abc490a1 MD |
166 | struct rcu_resize_work { |
167 | struct rcu_head head; | |
14044b37 | 168 | struct cds_lfht *ht; |
abc490a1 | 169 | }; |
2ed95849 | 170 | |
abc490a1 MD |
171 | /* |
172 | * Algorithm to reverse bits in a word by lookup table, extended to | |
173 | * 64-bit words. | |
f9830efd | 174 | * Source: |
abc490a1 | 175 | * http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable |
f9830efd | 176 | * Originally from Public Domain. |
abc490a1 MD |
177 | */ |
178 | ||
179 | static const uint8_t BitReverseTable256[256] = | |
2ed95849 | 180 | { |
abc490a1 MD |
181 | #define R2(n) (n), (n) + 2*64, (n) + 1*64, (n) + 3*64 |
182 | #define R4(n) R2(n), R2((n) + 2*16), R2((n) + 1*16), R2((n) + 3*16) | |
183 | #define R6(n) R4(n), R4((n) + 2*4 ), R4((n) + 1*4 ), R4((n) + 3*4 ) | |
184 | R6(0), R6(2), R6(1), R6(3) | |
185 | }; | |
186 | #undef R2 | |
187 | #undef R4 | |
188 | #undef R6 | |
2ed95849 | 189 | |
abc490a1 MD |
190 | static |
191 | uint8_t bit_reverse_u8(uint8_t v) | |
192 | { | |
193 | return BitReverseTable256[v]; | |
194 | } | |
ab7d5fc6 | 195 | |
abc490a1 MD |
196 | static __attribute__((unused)) |
197 | uint32_t bit_reverse_u32(uint32_t v) | |
198 | { | |
199 | return ((uint32_t) bit_reverse_u8(v) << 24) | | |
200 | ((uint32_t) bit_reverse_u8(v >> 8) << 16) | | |
201 | ((uint32_t) bit_reverse_u8(v >> 16) << 8) | | |
202 | ((uint32_t) bit_reverse_u8(v >> 24)); | |
2ed95849 MD |
203 | } |
204 | ||
abc490a1 MD |
205 | static __attribute__((unused)) |
206 | uint64_t bit_reverse_u64(uint64_t v) | |
2ed95849 | 207 | { |
abc490a1 MD |
208 | return ((uint64_t) bit_reverse_u8(v) << 56) | |
209 | ((uint64_t) bit_reverse_u8(v >> 8) << 48) | | |
210 | ((uint64_t) bit_reverse_u8(v >> 16) << 40) | | |
211 | ((uint64_t) bit_reverse_u8(v >> 24) << 32) | | |
212 | ((uint64_t) bit_reverse_u8(v >> 32) << 24) | | |
213 | ((uint64_t) bit_reverse_u8(v >> 40) << 16) | | |
214 | ((uint64_t) bit_reverse_u8(v >> 48) << 8) | | |
215 | ((uint64_t) bit_reverse_u8(v >> 56)); | |
216 | } | |
217 | ||
218 | static | |
219 | unsigned long bit_reverse_ulong(unsigned long v) | |
220 | { | |
221 | #if (CAA_BITS_PER_LONG == 32) | |
222 | return bit_reverse_u32(v); | |
223 | #else | |
224 | return bit_reverse_u64(v); | |
225 | #endif | |
226 | } | |
227 | ||
f9830efd | 228 | /* |
24365af7 MD |
229 | * fls: returns the position of the most significant bit. |
230 | * Returns 0 if no bit is set, else returns the position of the most | |
231 | * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit). | |
f9830efd | 232 | */ |
24365af7 MD |
233 | #if defined(__i386) || defined(__x86_64) |
234 | static inline | |
235 | unsigned int fls_u32(uint32_t x) | |
f9830efd | 236 | { |
24365af7 MD |
237 | int r; |
238 | ||
239 | asm("bsrl %1,%0\n\t" | |
240 | "jnz 1f\n\t" | |
241 | "movl $-1,%0\n\t" | |
242 | "1:\n\t" | |
243 | : "=r" (r) : "rm" (x)); | |
244 | return r + 1; | |
245 | } | |
246 | #define HAS_FLS_U32 | |
247 | #endif | |
248 | ||
249 | #if defined(__x86_64) | |
250 | static inline | |
251 | unsigned int fls_u64(uint64_t x) | |
252 | { | |
253 | long r; | |
254 | ||
255 | asm("bsrq %1,%0\n\t" | |
256 | "jnz 1f\n\t" | |
257 | "movq $-1,%0\n\t" | |
258 | "1:\n\t" | |
259 | : "=r" (r) : "rm" (x)); | |
260 | return r + 1; | |
261 | } | |
262 | #define HAS_FLS_U64 | |
263 | #endif | |
264 | ||
265 | #ifndef HAS_FLS_U64 | |
266 | static __attribute__((unused)) | |
267 | unsigned int fls_u64(uint64_t x) | |
268 | { | |
269 | unsigned int r = 64; | |
270 | ||
271 | if (!x) | |
272 | return 0; | |
273 | ||
274 | if (!(x & 0xFFFFFFFF00000000ULL)) { | |
275 | x <<= 32; | |
276 | r -= 32; | |
277 | } | |
278 | if (!(x & 0xFFFF000000000000ULL)) { | |
279 | x <<= 16; | |
280 | r -= 16; | |
281 | } | |
282 | if (!(x & 0xFF00000000000000ULL)) { | |
283 | x <<= 8; | |
284 | r -= 8; | |
285 | } | |
286 | if (!(x & 0xF000000000000000ULL)) { | |
287 | x <<= 4; | |
288 | r -= 4; | |
289 | } | |
290 | if (!(x & 0xC000000000000000ULL)) { | |
291 | x <<= 2; | |
292 | r -= 2; | |
293 | } | |
294 | if (!(x & 0x8000000000000000ULL)) { | |
295 | x <<= 1; | |
296 | r -= 1; | |
297 | } | |
298 | return r; | |
299 | } | |
300 | #endif | |
301 | ||
302 | #ifndef HAS_FLS_U32 | |
303 | static __attribute__((unused)) | |
304 | unsigned int fls_u32(uint32_t x) | |
305 | { | |
306 | unsigned int r = 32; | |
f9830efd | 307 | |
24365af7 MD |
308 | if (!x) |
309 | return 0; | |
310 | if (!(x & 0xFFFF0000U)) { | |
311 | x <<= 16; | |
312 | r -= 16; | |
313 | } | |
314 | if (!(x & 0xFF000000U)) { | |
315 | x <<= 8; | |
316 | r -= 8; | |
317 | } | |
318 | if (!(x & 0xF0000000U)) { | |
319 | x <<= 4; | |
320 | r -= 4; | |
321 | } | |
322 | if (!(x & 0xC0000000U)) { | |
323 | x <<= 2; | |
324 | r -= 2; | |
325 | } | |
326 | if (!(x & 0x80000000U)) { | |
327 | x <<= 1; | |
328 | r -= 1; | |
329 | } | |
330 | return r; | |
331 | } | |
332 | #endif | |
333 | ||
334 | unsigned int fls_ulong(unsigned long x) | |
f9830efd | 335 | { |
24365af7 MD |
336 | #if (CAA_BITS_PER_lONG == 32) |
337 | return fls_u32(x); | |
338 | #else | |
339 | return fls_u64(x); | |
340 | #endif | |
341 | } | |
f9830efd | 342 | |
24365af7 MD |
343 | int get_count_order_u32(uint32_t x) |
344 | { | |
345 | int order; | |
346 | ||
347 | order = fls_u32(x) - 1; | |
348 | if (x & (x - 1)) | |
349 | order++; | |
350 | return order; | |
351 | } | |
352 | ||
353 | int get_count_order_ulong(unsigned long x) | |
354 | { | |
355 | int order; | |
356 | ||
357 | order = fls_ulong(x) - 1; | |
358 | if (x & (x - 1)) | |
359 | order++; | |
360 | return order; | |
f9830efd MD |
361 | } |
362 | ||
363 | static | |
14044b37 | 364 | void cds_lfht_resize_lazy(struct cds_lfht *ht, struct rcu_table *t, int growth); |
f9830efd | 365 | |
df44348d MD |
366 | /* |
367 | * If the sched_getcpu() and sysconf(_SC_NPROCESSORS_CONF) calls are | |
368 | * available, then we support hash table item accounting. | |
369 | * In the unfortunate event the number of CPUs reported would be | |
370 | * inaccurate, we use modulo arithmetic on the number of CPUs we got. | |
371 | */ | |
372 | ||
373 | #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) | |
374 | ||
375 | static long nr_cpus_mask = -1; | |
376 | ||
377 | static | |
378 | struct ht_items_count *alloc_per_cpu_items_count(void) | |
379 | { | |
380 | struct ht_items_count *count; | |
381 | ||
382 | switch (nr_cpus_mask) { | |
383 | case -2: | |
384 | return NULL; | |
385 | case -1: | |
386 | { | |
387 | long maxcpus; | |
388 | ||
389 | maxcpus = sysconf(_SC_NPROCESSORS_CONF); | |
390 | if (maxcpus <= 0) { | |
391 | nr_cpus_mask = -2; | |
392 | return NULL; | |
393 | } | |
394 | /* | |
395 | * round up number of CPUs to next power of two, so we | |
396 | * can use & for modulo. | |
397 | */ | |
398 | maxcpus = 1UL << get_count_order_ulong(maxcpus); | |
399 | nr_cpus_mask = maxcpus - 1; | |
400 | } | |
401 | /* Fall-through */ | |
402 | default: | |
403 | return calloc(nr_cpus_mask + 1, sizeof(*count)); | |
404 | } | |
405 | } | |
406 | ||
407 | static | |
408 | void free_per_cpu_items_count(struct ht_items_count *count) | |
409 | { | |
410 | free(count); | |
411 | } | |
412 | ||
413 | static | |
414 | int ht_get_cpu(void) | |
415 | { | |
416 | int cpu; | |
417 | ||
418 | assert(nr_cpus_mask >= 0); | |
419 | cpu = sched_getcpu(); | |
420 | if (unlikely(cpu < 0)) | |
421 | return cpu; | |
422 | else | |
423 | return cpu & nr_cpus_mask; | |
424 | } | |
425 | ||
426 | static | |
427 | unsigned long ht_count_update(struct cds_lfht *ht, unsigned int value) | |
428 | { | |
429 | int cpu; | |
430 | ||
431 | if (unlikely(!ht->percpu_count)) | |
432 | return 0; | |
433 | cpu = ht_get_cpu(); | |
434 | if (unlikely(cpu < 0)) | |
435 | return 0; | |
436 | return uatomic_add_return(&ht->percpu_count[cpu].v, 1); | |
437 | } | |
438 | ||
439 | static | |
440 | void ht_count_add(struct cds_lfht *ht, struct rcu_table *t) | |
441 | { | |
442 | unsigned long percpu_count; | |
443 | ||
444 | percpu_count = ht_count_update(ht, 1); | |
445 | if (unlikely(!(percpu_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) { | |
446 | unsigned long count; | |
447 | ||
448 | dbg_printf("add percpu %lu\n", percpu_count); | |
449 | count = uatomic_add_return(&ht->count, | |
450 | 1UL << COUNT_COMMIT_ORDER); | |
451 | /* If power of 2 */ | |
452 | if (!(count & (count - 1))) { | |
453 | dbg_printf("add global %lu\n", count); | |
454 | cds_lfht_resize_lazy(ht, t, 1); | |
455 | } | |
456 | } | |
457 | } | |
458 | ||
459 | static | |
460 | void ht_count_remove(struct cds_lfht *ht, struct rcu_table *t) | |
461 | { | |
462 | unsigned long percpu_count; | |
463 | ||
464 | percpu_count = ht_count_update(ht, -1); | |
465 | if (unlikely(!(percpu_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) { | |
466 | unsigned long count; | |
467 | ||
468 | dbg_printf("remove percpu %lu\n", percpu_count); | |
469 | count = uatomic_add_return(&ht->count, | |
470 | 1UL << COUNT_COMMIT_ORDER); | |
471 | /* If power of 2 */ | |
472 | if (!(count & (count - 1))) { | |
473 | dbg_printf("remove global %lu\n", count); | |
474 | cds_lfht_resize_lazy(ht, t, -1); | |
475 | } | |
476 | } | |
477 | } | |
478 | ||
479 | #else /* #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */ | |
480 | ||
481 | static const long nr_cpus_mask = -1; | |
482 | ||
483 | static | |
484 | struct ht_items_count *alloc_per_cpu_items_count(void) | |
485 | { | |
486 | return NULL; | |
487 | } | |
488 | ||
489 | static | |
490 | void free_per_cpu_items_count(struct ht_items_count *count) | |
491 | { | |
492 | } | |
493 | ||
494 | static | |
495 | void ht_count_add(struct cds_lfht *ht) | |
496 | { | |
497 | } | |
498 | ||
499 | static | |
500 | void ht_count_remove(struct cds_lfht *ht) | |
501 | { | |
502 | } | |
503 | ||
504 | #endif /* #else #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */ | |
505 | ||
506 | ||
f9830efd | 507 | static |
14044b37 | 508 | void check_resize(struct cds_lfht *ht, struct rcu_table *t, |
f9830efd MD |
509 | uint32_t chain_len) |
510 | { | |
df44348d | 511 | return; //TEST |
24365af7 | 512 | if (chain_len > 100) |
f0c29ed7 | 513 | dbg_printf("WARNING: large chain length: %u.\n", |
24365af7 | 514 | chain_len); |
3390d470 | 515 | if (chain_len >= CHAIN_LEN_RESIZE_THRESHOLD) |
14044b37 | 516 | cds_lfht_resize_lazy(ht, t, |
01370f0b | 517 | get_count_order_u32(chain_len - (CHAIN_LEN_TARGET - 1))); |
f9830efd MD |
518 | } |
519 | ||
abc490a1 | 520 | static |
14044b37 | 521 | struct cds_lfht_node *clear_flag(struct cds_lfht_node *node) |
abc490a1 | 522 | { |
14044b37 | 523 | return (struct cds_lfht_node *) (((unsigned long) node) & ~FLAGS_MASK); |
abc490a1 MD |
524 | } |
525 | ||
526 | static | |
14044b37 | 527 | int is_removed(struct cds_lfht_node *node) |
abc490a1 | 528 | { |
d37166c6 | 529 | return ((unsigned long) node) & REMOVED_FLAG; |
abc490a1 MD |
530 | } |
531 | ||
532 | static | |
14044b37 | 533 | struct cds_lfht_node *flag_removed(struct cds_lfht_node *node) |
abc490a1 | 534 | { |
14044b37 | 535 | return (struct cds_lfht_node *) (((unsigned long) node) | REMOVED_FLAG); |
abc490a1 MD |
536 | } |
537 | ||
f5596c94 | 538 | static |
14044b37 | 539 | int is_dummy(struct cds_lfht_node *node) |
f5596c94 MD |
540 | { |
541 | return ((unsigned long) node) & DUMMY_FLAG; | |
542 | } | |
543 | ||
544 | static | |
14044b37 | 545 | struct cds_lfht_node *flag_dummy(struct cds_lfht_node *node) |
f5596c94 | 546 | { |
14044b37 | 547 | return (struct cds_lfht_node *) (((unsigned long) node) | DUMMY_FLAG); |
f5596c94 MD |
548 | } |
549 | ||
abc490a1 | 550 | static |
f9830efd | 551 | unsigned long _uatomic_max(unsigned long *ptr, unsigned long v) |
abc490a1 MD |
552 | { |
553 | unsigned long old1, old2; | |
554 | ||
555 | old1 = uatomic_read(ptr); | |
556 | do { | |
557 | old2 = old1; | |
558 | if (old2 >= v) | |
f9830efd | 559 | return old2; |
abc490a1 | 560 | } while ((old1 = uatomic_cmpxchg(ptr, old2, v)) != old2); |
f9830efd | 561 | return v; |
abc490a1 MD |
562 | } |
563 | ||
273399de MD |
564 | /* |
565 | * Remove all logically deleted nodes from a bucket up to a certain node key. | |
566 | */ | |
567 | static | |
14044b37 | 568 | void _cds_lfht_gc_bucket(struct cds_lfht_node *dummy, struct cds_lfht_node *node) |
273399de | 569 | { |
14044b37 | 570 | struct cds_lfht_node *iter_prev, *iter, *next, *new_next; |
273399de MD |
571 | |
572 | for (;;) { | |
573 | iter_prev = dummy; | |
574 | /* We can always skip the dummy node initially */ | |
cc4fcb10 MD |
575 | iter = rcu_dereference(iter_prev->p.next); |
576 | assert(iter_prev->p.reverse_hash <= node->p.reverse_hash); | |
273399de | 577 | for (;;) { |
a2974903 | 578 | if (unlikely(!clear_flag(iter))) |
479c8a32 | 579 | return; |
76412f24 | 580 | if (likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash)) |
273399de | 581 | return; |
cc4fcb10 | 582 | next = rcu_dereference(clear_flag(iter)->p.next); |
76412f24 | 583 | if (likely(is_removed(next))) |
273399de | 584 | break; |
b453eae1 | 585 | iter_prev = clear_flag(iter); |
273399de MD |
586 | iter = next; |
587 | } | |
588 | assert(!is_removed(iter)); | |
f5596c94 MD |
589 | if (is_dummy(iter)) |
590 | new_next = flag_dummy(clear_flag(next)); | |
591 | else | |
592 | new_next = clear_flag(next); | |
593 | (void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next); | |
273399de MD |
594 | } |
595 | } | |
596 | ||
abc490a1 | 597 | static |
14044b37 MD |
598 | struct cds_lfht_node *_cds_lfht_add(struct cds_lfht *ht, struct rcu_table *t, |
599 | struct cds_lfht_node *node, int unique, int dummy) | |
abc490a1 | 600 | { |
14044b37 | 601 | struct cds_lfht_node *iter_prev, *iter, *next, *new_node, *new_next, |
f5596c94 | 602 | *dummy_node; |
14044b37 | 603 | struct _cds_lfht_node *lookup; |
24365af7 | 604 | unsigned long hash, index, order; |
abc490a1 | 605 | |
18117871 | 606 | if (!t->size) { |
f5596c94 MD |
607 | assert(dummy); |
608 | node->p.next = flag_dummy(NULL); | |
18117871 MD |
609 | return node; /* Initial first add (head) */ |
610 | } | |
cc4fcb10 | 611 | hash = bit_reverse_ulong(node->p.reverse_hash); |
abc490a1 | 612 | for (;;) { |
f9830efd | 613 | uint32_t chain_len = 0; |
abc490a1 | 614 | |
11519af6 MD |
615 | /* |
616 | * iter_prev points to the non-removed node prior to the | |
617 | * insert location. | |
11519af6 | 618 | */ |
24365af7 MD |
619 | index = hash & (t->size - 1); |
620 | order = get_count_order_ulong(index + 1); | |
621 | lookup = &t->tbl[order][index & ((1UL << (order - 1)) - 1)]; | |
14044b37 | 622 | iter_prev = (struct cds_lfht_node *) lookup; |
11519af6 | 623 | /* We can always skip the dummy node initially */ |
cc4fcb10 MD |
624 | iter = rcu_dereference(iter_prev->p.next); |
625 | assert(iter_prev->p.reverse_hash <= node->p.reverse_hash); | |
abc490a1 | 626 | for (;;) { |
a2974903 | 627 | if (unlikely(!clear_flag(iter))) |
273399de | 628 | goto insert; |
76412f24 | 629 | if (likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash)) |
273399de | 630 | goto insert; |
cc4fcb10 | 631 | next = rcu_dereference(clear_flag(iter)->p.next); |
76412f24 | 632 | if (unlikely(is_removed(next))) |
9dba85be | 633 | goto gc_node; |
e43f23f8 | 634 | if (unique |
1b81fe1a | 635 | && !is_dummy(next) |
e43f23f8 MD |
636 | && !ht->compare_fct(node->key, node->key_len, |
637 | clear_flag(iter)->key, | |
638 | clear_flag(iter)->key_len)) | |
18117871 | 639 | return clear_flag(iter); |
11519af6 | 640 | /* Only account for identical reverse hash once */ |
24365af7 MD |
641 | if (iter_prev->p.reverse_hash != clear_flag(iter)->p.reverse_hash |
642 | && !is_dummy(next)) | |
11519af6 MD |
643 | check_resize(ht, t, ++chain_len); |
644 | iter_prev = clear_flag(iter); | |
273399de | 645 | iter = next; |
abc490a1 | 646 | } |
273399de | 647 | insert: |
7ec59d3b | 648 | assert(node != clear_flag(iter)); |
11519af6 | 649 | assert(!is_removed(iter_prev)); |
f000907d | 650 | assert(iter_prev != node); |
f5596c94 | 651 | if (!dummy) |
1b81fe1a | 652 | node->p.next = clear_flag(iter); |
f5596c94 | 653 | else |
1b81fe1a | 654 | node->p.next = flag_dummy(clear_flag(iter)); |
f5596c94 MD |
655 | if (is_dummy(iter)) |
656 | new_node = flag_dummy(node); | |
657 | else | |
658 | new_node = node; | |
cc4fcb10 | 659 | if (uatomic_cmpxchg(&iter_prev->p.next, iter, |
f5596c94 | 660 | new_node) != iter) |
273399de | 661 | continue; /* retry */ |
11519af6 | 662 | else |
273399de | 663 | goto gc_end; |
9dba85be MD |
664 | gc_node: |
665 | assert(!is_removed(iter)); | |
f5596c94 MD |
666 | if (is_dummy(iter)) |
667 | new_next = flag_dummy(clear_flag(next)); | |
668 | else | |
669 | new_next = clear_flag(next); | |
670 | (void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next); | |
273399de | 671 | /* retry */ |
464a1ec9 | 672 | } |
273399de MD |
673 | gc_end: |
674 | /* Garbage collect logically removed nodes in the bucket */ | |
24365af7 MD |
675 | index = hash & (t->size - 1); |
676 | order = get_count_order_ulong(index + 1); | |
677 | lookup = &t->tbl[order][index & ((1UL << (order - 1)) - 1)]; | |
14044b37 MD |
678 | dummy_node = (struct cds_lfht_node *) lookup; |
679 | _cds_lfht_gc_bucket(dummy_node, node); | |
18117871 | 680 | return node; |
abc490a1 | 681 | } |
464a1ec9 | 682 | |
abc490a1 | 683 | static |
14044b37 MD |
684 | int _cds_lfht_remove(struct cds_lfht *ht, struct rcu_table *t, |
685 | struct cds_lfht_node *node) | |
abc490a1 | 686 | { |
14044b37 MD |
687 | struct cds_lfht_node *dummy, *next, *old; |
688 | struct _cds_lfht_node *lookup; | |
abc490a1 | 689 | int flagged = 0; |
24365af7 | 690 | unsigned long hash, index, order; |
5e28c532 | 691 | |
7ec59d3b | 692 | /* logically delete the node */ |
cc4fcb10 | 693 | old = rcu_dereference(node->p.next); |
7ec59d3b MD |
694 | do { |
695 | next = old; | |
76412f24 | 696 | if (unlikely(is_removed(next))) |
7ec59d3b | 697 | goto end; |
1b81fe1a | 698 | assert(!is_dummy(next)); |
cc4fcb10 | 699 | old = uatomic_cmpxchg(&node->p.next, next, |
7ec59d3b MD |
700 | flag_removed(next)); |
701 | } while (old != next); | |
702 | ||
703 | /* We performed the (logical) deletion. */ | |
704 | flagged = 1; | |
705 | ||
706 | /* | |
707 | * Ensure that the node is not visible to readers anymore: lookup for | |
273399de MD |
708 | * the node, and remove it (along with any other logically removed node) |
709 | * if found. | |
11519af6 | 710 | */ |
cc4fcb10 | 711 | hash = bit_reverse_ulong(node->p.reverse_hash); |
24365af7 MD |
712 | index = hash & (t->size - 1); |
713 | order = get_count_order_ulong(index + 1); | |
714 | lookup = &t->tbl[order][index & ((1UL << (order - 1)) - 1)]; | |
14044b37 MD |
715 | dummy = (struct cds_lfht_node *) lookup; |
716 | _cds_lfht_gc_bucket(dummy, node); | |
2ed95849 | 717 | end: |
11519af6 MD |
718 | /* |
719 | * Only the flagging action indicated that we (and no other) | |
720 | * removed the node from the hash. | |
721 | */ | |
7ec59d3b | 722 | if (flagged) { |
cc4fcb10 | 723 | assert(is_removed(rcu_dereference(node->p.next))); |
11519af6 | 724 | return 0; |
7ec59d3b | 725 | } else |
11519af6 | 726 | return -ENOENT; |
abc490a1 | 727 | } |
2ed95849 | 728 | |
abc490a1 | 729 | static |
14044b37 | 730 | void init_table(struct cds_lfht *ht, struct rcu_table *t, |
24365af7 MD |
731 | unsigned long first_order, unsigned long len_order) |
732 | { | |
733 | unsigned long i, end_order; | |
734 | ||
f0c29ed7 | 735 | dbg_printf("init table: first_order %lu end_order %lu\n", |
24365af7 MD |
736 | first_order, first_order + len_order); |
737 | end_order = first_order + len_order; | |
738 | t->size = !first_order ? 0 : (1UL << (first_order - 1)); | |
739 | for (i = first_order; i < end_order; i++) { | |
740 | unsigned long j, len; | |
741 | ||
742 | len = !i ? 1 : 1UL << (i - 1); | |
f0c29ed7 | 743 | dbg_printf("init order %lu len: %lu\n", i, len); |
14044b37 | 744 | t->tbl[i] = calloc(len, sizeof(struct _cds_lfht_node)); |
24365af7 | 745 | for (j = 0; j < len; j++) { |
f0c29ed7 | 746 | dbg_printf("init entry: i %lu j %lu hash %lu\n", |
24365af7 | 747 | i, j, !i ? 0 : (1UL << (i - 1)) + j); |
14044b37 MD |
748 | struct cds_lfht_node *new_node = |
749 | (struct cds_lfht_node *) &t->tbl[i][j]; | |
24365af7 MD |
750 | new_node->p.reverse_hash = |
751 | bit_reverse_ulong(!i ? 0 : (1UL << (i - 1)) + j); | |
14044b37 | 752 | (void) _cds_lfht_add(ht, t, new_node, 0, 1); |
33c7c748 MD |
753 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
754 | break; | |
24365af7 MD |
755 | } |
756 | /* Update table size */ | |
757 | t->size = !i ? 1 : (1UL << i); | |
f0c29ed7 | 758 | dbg_printf("init new size: %lu\n", t->size); |
33c7c748 MD |
759 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
760 | break; | |
abc490a1 | 761 | } |
24365af7 | 762 | t->resize_target = t->size; |
11519af6 | 763 | t->resize_initiated = 0; |
2ed95849 MD |
764 | } |
765 | ||
14044b37 MD |
766 | struct cds_lfht *cds_lfht_new(cds_lfht_hash_fct hash_fct, |
767 | cds_lfht_compare_fct compare_fct, | |
768 | unsigned long hash_seed, | |
769 | unsigned long init_size, | |
770 | void (*cds_lfht_call_rcu)(struct rcu_head *head, | |
771 | void (*func)(struct rcu_head *head))) | |
abc490a1 | 772 | { |
14044b37 | 773 | struct cds_lfht *ht; |
24365af7 | 774 | unsigned long order; |
abc490a1 | 775 | |
8129be4e | 776 | /* init_size must be power of two */ |
49619ea0 | 777 | if (init_size && (init_size & (init_size - 1))) |
8129be4e | 778 | return NULL; |
14044b37 | 779 | ht = calloc(1, sizeof(struct cds_lfht)); |
abc490a1 | 780 | ht->hash_fct = hash_fct; |
732ad076 MD |
781 | ht->compare_fct = compare_fct; |
782 | ht->hash_seed = hash_seed; | |
14044b37 | 783 | ht->cds_lfht_call_rcu = cds_lfht_call_rcu; |
848d4088 | 784 | ht->in_progress_resize = 0; |
df44348d | 785 | ht->percpu_count = alloc_per_cpu_items_count(); |
abc490a1 MD |
786 | /* this mutex should not nest in read-side C.S. */ |
787 | pthread_mutex_init(&ht->resize_mutex, NULL); | |
24365af7 | 788 | order = get_count_order_ulong(max(init_size, 1)) + 1; |
14044b37 MD |
789 | ht->t = calloc(1, sizeof(struct cds_lfht) |
790 | + (order * sizeof(struct _cds_lfht_node *))); | |
abc490a1 | 791 | ht->t->size = 0; |
f000907d | 792 | pthread_mutex_lock(&ht->resize_mutex); |
24365af7 | 793 | init_table(ht, ht->t, 0, order); |
f000907d | 794 | pthread_mutex_unlock(&ht->resize_mutex); |
abc490a1 MD |
795 | return ht; |
796 | } | |
797 | ||
14044b37 | 798 | struct cds_lfht_node *cds_lfht_lookup(struct cds_lfht *ht, void *key, size_t key_len) |
2ed95849 | 799 | { |
395270b6 | 800 | struct rcu_table *t; |
14044b37 MD |
801 | struct cds_lfht_node *node, *next; |
802 | struct _cds_lfht_node *lookup; | |
24365af7 | 803 | unsigned long hash, reverse_hash, index, order; |
2ed95849 | 804 | |
732ad076 | 805 | hash = ht->hash_fct(key, key_len, ht->hash_seed); |
abc490a1 | 806 | reverse_hash = bit_reverse_ulong(hash); |
464a1ec9 | 807 | |
395270b6 | 808 | t = rcu_dereference(ht->t); |
24365af7 MD |
809 | index = hash & (t->size - 1); |
810 | order = get_count_order_ulong(index + 1); | |
811 | lookup = &t->tbl[order][index & ((1UL << (order - 1)) - 1)]; | |
f0c29ed7 | 812 | dbg_printf("lookup hash %lu index %lu order %lu aridx %lu\n", |
24365af7 | 813 | hash, index, order, index & ((1UL << (order - 1)) - 1)); |
14044b37 | 814 | node = (struct cds_lfht_node *) lookup; |
2ed95849 | 815 | for (;;) { |
abc490a1 MD |
816 | if (unlikely(!node)) |
817 | break; | |
cc4fcb10 | 818 | if (unlikely(node->p.reverse_hash > reverse_hash)) { |
abc490a1 MD |
819 | node = NULL; |
820 | break; | |
2ed95849 | 821 | } |
1b81fe1a MD |
822 | next = rcu_dereference(node->p.next); |
823 | if (likely(!is_removed(next)) | |
824 | && !is_dummy(next) | |
49c2e2d6 | 825 | && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) { |
273399de | 826 | break; |
2ed95849 | 827 | } |
1b81fe1a | 828 | node = clear_flag(next); |
2ed95849 | 829 | } |
1b81fe1a | 830 | assert(!node || !is_dummy(rcu_dereference(node->p.next))); |
abc490a1 MD |
831 | return node; |
832 | } | |
e0ba718a | 833 | |
a481e5ff MD |
834 | struct cds_lfht_node *cds_lfht_next(struct cds_lfht *ht, |
835 | struct cds_lfht_node *node) | |
836 | { | |
837 | struct cds_lfht_node *next; | |
838 | unsigned long reverse_hash; | |
839 | void *key; | |
840 | size_t key_len; | |
841 | ||
842 | reverse_hash = node->p.reverse_hash; | |
843 | key = node->key; | |
844 | key_len = node->key_len; | |
845 | next = rcu_dereference(node->p.next); | |
846 | node = clear_flag(next); | |
847 | ||
848 | for (;;) { | |
849 | if (unlikely(!node)) | |
850 | break; | |
851 | if (unlikely(node->p.reverse_hash > reverse_hash)) { | |
852 | node = NULL; | |
853 | break; | |
854 | } | |
855 | next = rcu_dereference(node->p.next); | |
856 | if (likely(!is_removed(next)) | |
857 | && !is_dummy(next) | |
858 | && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) { | |
859 | break; | |
860 | } | |
861 | node = clear_flag(next); | |
862 | } | |
863 | assert(!node || !is_dummy(rcu_dereference(node->p.next))); | |
864 | return node; | |
865 | } | |
866 | ||
14044b37 | 867 | void cds_lfht_add(struct cds_lfht *ht, struct cds_lfht_node *node) |
abc490a1 MD |
868 | { |
869 | struct rcu_table *t; | |
49c2e2d6 | 870 | unsigned long hash; |
ab7d5fc6 | 871 | |
49c2e2d6 | 872 | hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed); |
cc4fcb10 | 873 | node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash); |
2ed95849 | 874 | |
abc490a1 | 875 | t = rcu_dereference(ht->t); |
14044b37 | 876 | (void) _cds_lfht_add(ht, t, node, 0, 0); |
df44348d | 877 | ht_count_add(ht, t); |
3eca1b8c MD |
878 | } |
879 | ||
14044b37 MD |
880 | struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, |
881 | struct cds_lfht_node *node) | |
3eca1b8c MD |
882 | { |
883 | struct rcu_table *t; | |
49c2e2d6 | 884 | unsigned long hash; |
df44348d | 885 | struct cds_lfht_node *ret; |
3eca1b8c | 886 | |
49c2e2d6 | 887 | hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed); |
cc4fcb10 | 888 | node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash); |
3eca1b8c MD |
889 | |
890 | t = rcu_dereference(ht->t); | |
df44348d MD |
891 | ret = _cds_lfht_add(ht, t, node, 1, 0); |
892 | if (ret != node) | |
893 | ht_count_add(ht, t); | |
894 | return ret; | |
2ed95849 MD |
895 | } |
896 | ||
14044b37 | 897 | int cds_lfht_remove(struct cds_lfht *ht, struct cds_lfht_node *node) |
2ed95849 | 898 | { |
abc490a1 | 899 | struct rcu_table *t; |
df44348d | 900 | int ret; |
abc490a1 MD |
901 | |
902 | t = rcu_dereference(ht->t); | |
df44348d MD |
903 | ret = _cds_lfht_remove(ht, t, node); |
904 | if (!ret) | |
905 | ht_count_remove(ht, t); | |
906 | return ret; | |
2ed95849 | 907 | } |
ab7d5fc6 | 908 | |
abc490a1 | 909 | static |
14044b37 | 910 | int cds_lfht_delete_dummy(struct cds_lfht *ht) |
674f7a69 | 911 | { |
395270b6 | 912 | struct rcu_table *t; |
14044b37 MD |
913 | struct cds_lfht_node *node; |
914 | struct _cds_lfht_node *lookup; | |
24365af7 | 915 | unsigned long order, i; |
674f7a69 | 916 | |
abc490a1 MD |
917 | t = ht->t; |
918 | /* Check that the table is empty */ | |
24365af7 | 919 | lookup = &t->tbl[0][0]; |
14044b37 | 920 | node = (struct cds_lfht_node *) lookup; |
abc490a1 | 921 | do { |
1b81fe1a MD |
922 | node = clear_flag(node)->p.next; |
923 | if (!is_dummy(node)) | |
abc490a1 | 924 | return -EPERM; |
273399de | 925 | assert(!is_removed(node)); |
a2974903 | 926 | } while (clear_flag(node)); |
abc490a1 | 927 | /* Internal sanity check: all nodes left should be dummy */ |
24365af7 MD |
928 | for (order = 0; order < get_count_order_ulong(t->size) + 1; order++) { |
929 | unsigned long len; | |
930 | ||
931 | len = !order ? 1 : 1UL << (order - 1); | |
932 | for (i = 0; i < len; i++) { | |
f0c29ed7 | 933 | dbg_printf("delete order %lu i %lu hash %lu\n", |
24365af7 MD |
934 | order, i, |
935 | bit_reverse_ulong(t->tbl[order][i].reverse_hash)); | |
936 | assert(is_dummy(t->tbl[order][i].next)); | |
937 | } | |
938 | free(t->tbl[order]); | |
674f7a69 | 939 | } |
abc490a1 | 940 | return 0; |
674f7a69 MD |
941 | } |
942 | ||
943 | /* | |
944 | * Should only be called when no more concurrent readers nor writers can | |
945 | * possibly access the table. | |
946 | */ | |
14044b37 | 947 | int cds_lfht_destroy(struct cds_lfht *ht) |
674f7a69 | 948 | { |
5e28c532 MD |
949 | int ret; |
950 | ||
848d4088 | 951 | /* Wait for in-flight resize operations to complete */ |
33c7c748 | 952 | CMM_STORE_SHARED(ht->in_progress_destroy, 1); |
848d4088 MD |
953 | while (uatomic_read(&ht->in_progress_resize)) |
954 | poll(NULL, 0, 100); /* wait for 100ms */ | |
14044b37 | 955 | ret = cds_lfht_delete_dummy(ht); |
abc490a1 MD |
956 | if (ret) |
957 | return ret; | |
395270b6 | 958 | free(ht->t); |
df44348d | 959 | free_per_cpu_items_count(ht->percpu_count); |
674f7a69 | 960 | free(ht); |
5e28c532 | 961 | return ret; |
674f7a69 MD |
962 | } |
963 | ||
14044b37 | 964 | void cds_lfht_count_nodes(struct cds_lfht *ht, |
273399de MD |
965 | unsigned long *count, |
966 | unsigned long *removed) | |
967 | { | |
968 | struct rcu_table *t; | |
14044b37 MD |
969 | struct cds_lfht_node *node, *next; |
970 | struct _cds_lfht_node *lookup; | |
24365af7 | 971 | unsigned long nr_dummy = 0; |
273399de MD |
972 | |
973 | *count = 0; | |
974 | *removed = 0; | |
975 | ||
976 | t = rcu_dereference(ht->t); | |
24365af7 MD |
977 | /* Count non-dummy nodes in the table */ |
978 | lookup = &t->tbl[0][0]; | |
14044b37 | 979 | node = (struct cds_lfht_node *) lookup; |
273399de | 980 | do { |
cc4fcb10 | 981 | next = rcu_dereference(node->p.next); |
273399de | 982 | if (is_removed(next)) { |
1b81fe1a | 983 | assert(!is_dummy(next)); |
273399de | 984 | (*removed)++; |
1b81fe1a | 985 | } else if (!is_dummy(next)) |
273399de | 986 | (*count)++; |
24365af7 MD |
987 | else |
988 | (nr_dummy)++; | |
273399de MD |
989 | node = clear_flag(next); |
990 | } while (node); | |
f0c29ed7 | 991 | dbg_printf("number of dummy nodes: %lu\n", nr_dummy); |
273399de MD |
992 | } |
993 | ||
abc490a1 | 994 | static |
14044b37 | 995 | void cds_lfht_free_table_cb(struct rcu_head *head) |
abc490a1 MD |
996 | { |
997 | struct rcu_table *t = | |
998 | caa_container_of(head, struct rcu_table, head); | |
999 | free(t); | |
1000 | } | |
1001 | ||
1002 | /* called with resize mutex held */ | |
1003 | static | |
14044b37 | 1004 | void _do_cds_lfht_resize(struct cds_lfht *ht) |
464a1ec9 | 1005 | { |
24365af7 | 1006 | unsigned long new_size, old_size, old_order, new_order; |
395270b6 | 1007 | struct rcu_table *new_t, *old_t; |
464a1ec9 | 1008 | |
395270b6 MD |
1009 | old_t = ht->t; |
1010 | old_size = old_t->size; | |
24365af7 | 1011 | old_order = get_count_order_ulong(old_size) + 1; |
464a1ec9 | 1012 | |
f9830efd | 1013 | new_size = CMM_LOAD_SHARED(old_t->resize_target); |
abc490a1 | 1014 | if (old_size == new_size) |
464a1ec9 | 1015 | return; |
24365af7 | 1016 | new_order = get_count_order_ulong(new_size) + 1; |
df44348d | 1017 | printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", |
df03fab8 | 1018 | old_size, old_order, new_size, new_order); |
14044b37 MD |
1019 | new_t = malloc(sizeof(struct cds_lfht) |
1020 | + (new_order * sizeof(struct _cds_lfht_node *))); | |
f000907d MD |
1021 | assert(new_size > old_size); |
1022 | memcpy(&new_t->tbl, &old_t->tbl, | |
14044b37 | 1023 | old_order * sizeof(struct _cds_lfht_node *)); |
24365af7 | 1024 | init_table(ht, new_t, old_order, new_order - old_order); |
f000907d MD |
1025 | /* Changing table and size atomically wrt lookups */ |
1026 | rcu_assign_pointer(ht->t, new_t); | |
14044b37 | 1027 | ht->cds_lfht_call_rcu(&old_t->head, cds_lfht_free_table_cb); |
464a1ec9 MD |
1028 | } |
1029 | ||
abc490a1 | 1030 | static |
f9830efd MD |
1031 | unsigned long resize_target_update(struct rcu_table *t, |
1032 | int growth_order) | |
464a1ec9 | 1033 | { |
f9830efd MD |
1034 | return _uatomic_max(&t->resize_target, |
1035 | t->size << growth_order); | |
464a1ec9 MD |
1036 | } |
1037 | ||
14044b37 | 1038 | void cds_lfht_resize(struct cds_lfht *ht, int growth) |
464a1ec9 | 1039 | { |
f9830efd MD |
1040 | struct rcu_table *t = rcu_dereference(ht->t); |
1041 | unsigned long target_size; | |
1042 | ||
f0c29ed7 MD |
1043 | if (growth < 0) { |
1044 | /* | |
1045 | * Silently refuse to shrink hash table. (not supported) | |
1046 | */ | |
1047 | dbg_printf("shrinking hash table not supported.\n"); | |
1048 | return; | |
1049 | } | |
1050 | ||
f9830efd MD |
1051 | target_size = resize_target_update(t, growth); |
1052 | if (t->size < target_size) { | |
11519af6 | 1053 | CMM_STORE_SHARED(t->resize_initiated, 1); |
f9830efd | 1054 | pthread_mutex_lock(&ht->resize_mutex); |
14044b37 | 1055 | _do_cds_lfht_resize(ht); |
f9830efd MD |
1056 | pthread_mutex_unlock(&ht->resize_mutex); |
1057 | } | |
abc490a1 | 1058 | } |
464a1ec9 | 1059 | |
abc490a1 MD |
1060 | static |
1061 | void do_resize_cb(struct rcu_head *head) | |
1062 | { | |
1063 | struct rcu_resize_work *work = | |
1064 | caa_container_of(head, struct rcu_resize_work, head); | |
14044b37 | 1065 | struct cds_lfht *ht = work->ht; |
abc490a1 MD |
1066 | |
1067 | pthread_mutex_lock(&ht->resize_mutex); | |
14044b37 | 1068 | _do_cds_lfht_resize(ht); |
abc490a1 MD |
1069 | pthread_mutex_unlock(&ht->resize_mutex); |
1070 | free(work); | |
848d4088 MD |
1071 | cmm_smp_mb(); /* finish resize before decrement */ |
1072 | uatomic_dec(&ht->in_progress_resize); | |
464a1ec9 MD |
1073 | } |
1074 | ||
abc490a1 | 1075 | static |
14044b37 | 1076 | void cds_lfht_resize_lazy(struct cds_lfht *ht, struct rcu_table *t, int growth) |
ab7d5fc6 | 1077 | { |
abc490a1 | 1078 | struct rcu_resize_work *work; |
f9830efd | 1079 | unsigned long target_size; |
abc490a1 | 1080 | |
f9830efd | 1081 | target_size = resize_target_update(t, growth); |
11519af6 | 1082 | if (!CMM_LOAD_SHARED(t->resize_initiated) && t->size < target_size) { |
848d4088 MD |
1083 | uatomic_inc(&ht->in_progress_resize); |
1084 | cmm_smp_mb(); /* increment resize count before calling it */ | |
f9830efd MD |
1085 | work = malloc(sizeof(*work)); |
1086 | work->ht = ht; | |
14044b37 | 1087 | ht->cds_lfht_call_rcu(&work->head, do_resize_cb); |
11519af6 | 1088 | CMM_STORE_SHARED(t->resize_initiated, 1); |
f9830efd | 1089 | } |
ab7d5fc6 | 1090 | } |