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fa68aa62 MD |
1 | /* |
2 | * rculfhash.c | |
3 | * | |
4 | * Userspace RCU library - Lock-Free Resizable 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 | |
21 | */ | |
22 | ||
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 Resizable 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 for small tables only allows expanding the hash table. | |
52 | * It is triggered automatically by detecting long chains in the add | |
53 | * operation. | |
54 | * - The resize operation for larger tables (and available through an | |
55 | * API) allows both expanding and shrinking the hash table. | |
56 | * - Per-CPU Split-counters are used to keep track of the number of | |
57 | * nodes within the hash table for automatic resize triggering. | |
58 | * - Resize operation initiated by long chain detection is executed by a | |
59 | * call_rcu thread, which keeps lock-freedom of add and remove. | |
60 | * - Resize operations are protected by a mutex. | |
61 | * - The removal operation is split in two parts: first, a "removed" | |
62 | * flag is set in the next pointer within the node to remove. Then, | |
63 | * a "garbage collection" is performed in the bucket containing the | |
64 | * removed node (from the start of the bucket up to the removed node). | |
65 | * All encountered nodes with "removed" flag set in their next | |
66 | * pointers are removed from the linked-list. If the cmpxchg used for | |
67 | * removal fails (due to concurrent garbage-collection or concurrent | |
68 | * add), we retry from the beginning of the bucket. This ensures that | |
69 | * the node with "removed" flag set is removed from the hash table | |
70 | * (not visible to lookups anymore) before the RCU read-side critical | |
71 | * section held across removal ends. Furthermore, this ensures that | |
72 | * the node with "removed" flag set is removed from the linked-list | |
73 | * before its memory is reclaimed. Only the thread which removal | |
74 | * successfully set the "removed" flag (with a cmpxchg) into a node's | |
75 | * next pointer is considered to have succeeded its removal (and thus | |
76 | * owns the node to reclaim). Because we garbage-collect starting from | |
77 | * an invariant node (the start-of-bucket dummy node) up to the | |
78 | * "removed" node (or find a reverse-hash that is higher), we are sure | |
79 | * that a successful traversal of the chain leads to a chain that is | |
80 | * present in the linked-list (the start node is never removed) and | |
81 | * that is does not contain the "removed" node anymore, even if | |
82 | * concurrent delete/add operations are changing the structure of the | |
83 | * list concurrently. | |
84 | * - The add operation performs gargage collection of buckets if it | |
85 | * encounters nodes with removed flag set in the bucket where it wants | |
86 | * to add its new node. This ensures lock-freedom of add operation by | |
87 | * helping the remover unlink nodes from the list rather than to wait | |
88 | * for it do to so. | |
89 | * - A RCU "order table" indexed by log2(hash index) is copied and | |
90 | * expanded by the resize operation. This order table allows finding | |
91 | * the "dummy node" tables. | |
92 | * - There is one dummy node table per hash index order. The size of | |
93 | * each dummy node table is half the number of hashes contained in | |
94 | * this order. | |
95 | * - call_rcu is used to garbage-collect the old order table. | |
96 | * - The per-order dummy node tables contain a compact version of the | |
97 | * hash table nodes. These tables are invariant after they are | |
98 | * populated into the hash table. | |
99 | * | |
100 | * A bit of ascii art explanation: | |
101 | * | |
102 | * Order index is the off-by-one compare to the actual power of 2 because | |
103 | * we use index 0 to deal with the 0 special-case. | |
104 | * | |
105 | * This shows the nodes for a small table ordered by reversed bits: | |
106 | * | |
107 | * bits reverse | |
108 | * 0 000 000 | |
109 | * 4 100 001 | |
110 | * 2 010 010 | |
111 | * 6 110 011 | |
112 | * 1 001 100 | |
113 | * 5 101 101 | |
114 | * 3 011 110 | |
115 | * 7 111 111 | |
116 | * | |
117 | * This shows the nodes in order of non-reversed bits, linked by | |
118 | * reversed-bit order. | |
119 | * | |
120 | * order bits reverse | |
121 | * 0 0 000 000 | |
122 | * | | |
123 | * 1 | 1 001 100 <- <- | |
124 | * | | | | | |
125 | * 2 | | 2 010 010 | | | |
126 | * | | | 3 011 110 | <- | | |
127 | * | | | | | | | | |
128 | * 3 -> | | | 4 100 001 | | | |
129 | * -> | | 5 101 101 | | |
130 | * -> | 6 110 011 | |
131 | * -> 7 111 111 | |
132 | */ | |
133 | ||
134 | #define _LGPL_SOURCE | |
135 | #include <stdlib.h> | |
136 | #include <errno.h> | |
137 | #include <assert.h> | |
138 | #include <stdio.h> | |
139 | #include <stdint.h> | |
140 | #include <string.h> | |
141 | ||
fa68aa62 MD |
142 | #include <urcu.h> |
143 | #include <urcu-call-rcu.h> | |
144 | #include <urcu/arch.h> | |
145 | #include <urcu/uatomic.h> | |
146 | #include <urcu/compiler.h> | |
fa68aa62 MD |
147 | #include <stdio.h> |
148 | #include <pthread.h> | |
149 | ||
f6a9efaa DG |
150 | #include "rculfhash.h" |
151 | ||
fa68aa62 MD |
152 | #ifdef DEBUG |
153 | #define dbg_printf(fmt, args...) printf("[debug rculfhash] " fmt, ## args) | |
154 | #else | |
155 | #define dbg_printf(fmt, args...) | |
156 | #endif | |
157 | ||
158 | /* | |
159 | * Per-CPU split-counters lazily update the global counter each 1024 | |
160 | * addition/removal. It automatically keeps track of resize required. | |
161 | * We use the bucket length as indicator for need to expand for small | |
162 | * tables and machines lacking per-cpu data suppport. | |
163 | */ | |
164 | #define COUNT_COMMIT_ORDER 10 | |
165 | #define CHAIN_LEN_TARGET 1 | |
166 | #define CHAIN_LEN_RESIZE_THRESHOLD 3 | |
167 | ||
168 | /* | |
169 | * Define the minimum table size. | |
170 | */ | |
171 | #define MIN_TABLE_SIZE 1 | |
172 | ||
173 | #if (CAA_BITS_PER_LONG == 32) | |
174 | #define MAX_TABLE_ORDER 32 | |
175 | #else | |
176 | #define MAX_TABLE_ORDER 64 | |
177 | #endif | |
178 | ||
179 | /* | |
180 | * Minimum number of dummy nodes to touch per thread to parallelize grow/shrink. | |
181 | */ | |
182 | #define MIN_PARTITION_PER_THREAD_ORDER 12 | |
183 | #define MIN_PARTITION_PER_THREAD (1UL << MIN_PARTITION_PER_THREAD_ORDER) | |
184 | ||
185 | #ifndef min | |
186 | #define min(a, b) ((a) < (b) ? (a) : (b)) | |
187 | #endif | |
188 | ||
189 | #ifndef max | |
190 | #define max(a, b) ((a) > (b) ? (a) : (b)) | |
191 | #endif | |
192 | ||
193 | /* | |
194 | * The removed flag needs to be updated atomically with the pointer. | |
195 | * It indicates that no node must attach to the node scheduled for | |
196 | * removal, and that node garbage collection must be performed. | |
197 | * The dummy flag does not require to be updated atomically with the | |
198 | * pointer, but it is added as a pointer low bit flag to save space. | |
199 | */ | |
200 | #define REMOVED_FLAG (1UL << 0) | |
201 | #define DUMMY_FLAG (1UL << 1) | |
202 | #define FLAGS_MASK ((1UL << 2) - 1) | |
203 | ||
204 | /* Value of the end pointer. Should not interact with flags. */ | |
205 | #define END_VALUE NULL | |
206 | ||
207 | struct ht_items_count { | |
208 | unsigned long add, del; | |
209 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); | |
210 | ||
211 | struct rcu_level { | |
212 | struct rcu_head head; | |
213 | struct _cds_lfht_node nodes[0]; | |
214 | }; | |
215 | ||
216 | struct rcu_table { | |
217 | unsigned long size; /* always a power of 2, shared (RCU) */ | |
218 | unsigned long resize_target; | |
219 | int resize_initiated; | |
220 | struct rcu_level *tbl[MAX_TABLE_ORDER]; | |
221 | }; | |
222 | ||
223 | struct cds_lfht { | |
224 | struct rcu_table t; | |
225 | cds_lfht_hash_fct hash_fct; | |
226 | cds_lfht_compare_fct compare_fct; | |
227 | unsigned long hash_seed; | |
228 | int flags; | |
229 | /* | |
230 | * We need to put the work threads offline (QSBR) when taking this | |
231 | * mutex, because we use synchronize_rcu within this mutex critical | |
232 | * section, which waits on read-side critical sections, and could | |
233 | * therefore cause grace-period deadlock if we hold off RCU G.P. | |
234 | * completion. | |
235 | */ | |
236 | pthread_mutex_t resize_mutex; /* resize mutex: add/del mutex */ | |
237 | unsigned int in_progress_resize, in_progress_destroy; | |
238 | void (*cds_lfht_call_rcu)(struct rcu_head *head, | |
239 | void (*func)(struct rcu_head *head)); | |
240 | void (*cds_lfht_synchronize_rcu)(void); | |
241 | void (*cds_lfht_rcu_read_lock)(void); | |
242 | void (*cds_lfht_rcu_read_unlock)(void); | |
243 | void (*cds_lfht_rcu_thread_offline)(void); | |
244 | void (*cds_lfht_rcu_thread_online)(void); | |
245 | void (*cds_lfht_rcu_register_thread)(void); | |
246 | void (*cds_lfht_rcu_unregister_thread)(void); | |
247 | pthread_attr_t *resize_attr; /* Resize threads attributes */ | |
248 | long count; /* global approximate item count */ | |
249 | struct ht_items_count *percpu_count; /* per-cpu item count */ | |
250 | }; | |
251 | ||
252 | struct rcu_resize_work { | |
253 | struct rcu_head head; | |
254 | struct cds_lfht *ht; | |
255 | }; | |
256 | ||
257 | struct partition_resize_work { | |
258 | struct rcu_head head; | |
259 | struct cds_lfht *ht; | |
260 | unsigned long i, start, len; | |
261 | void (*fct)(struct cds_lfht *ht, unsigned long i, | |
262 | unsigned long start, unsigned long len); | |
263 | }; | |
264 | ||
265 | enum add_mode { | |
266 | ADD_DEFAULT = 0, | |
267 | ADD_UNIQUE = 1, | |
268 | ADD_REPLACE = 2, | |
269 | }; | |
270 | ||
271 | static | |
272 | struct cds_lfht_node *_cds_lfht_add(struct cds_lfht *ht, | |
273 | unsigned long size, | |
274 | struct cds_lfht_node *node, | |
275 | enum add_mode mode, int dummy); | |
276 | ||
277 | /* | |
278 | * Algorithm to reverse bits in a word by lookup table, extended to | |
279 | * 64-bit words. | |
280 | * Source: | |
281 | * http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable | |
282 | * Originally from Public Domain. | |
283 | */ | |
284 | ||
285 | static const uint8_t BitReverseTable256[256] = | |
286 | { | |
287 | #define R2(n) (n), (n) + 2*64, (n) + 1*64, (n) + 3*64 | |
288 | #define R4(n) R2(n), R2((n) + 2*16), R2((n) + 1*16), R2((n) + 3*16) | |
289 | #define R6(n) R4(n), R4((n) + 2*4 ), R4((n) + 1*4 ), R4((n) + 3*4 ) | |
290 | R6(0), R6(2), R6(1), R6(3) | |
291 | }; | |
292 | #undef R2 | |
293 | #undef R4 | |
294 | #undef R6 | |
295 | ||
296 | static | |
297 | uint8_t bit_reverse_u8(uint8_t v) | |
298 | { | |
299 | return BitReverseTable256[v]; | |
300 | } | |
301 | ||
302 | static __attribute__((unused)) | |
303 | uint32_t bit_reverse_u32(uint32_t v) | |
304 | { | |
305 | return ((uint32_t) bit_reverse_u8(v) << 24) | | |
306 | ((uint32_t) bit_reverse_u8(v >> 8) << 16) | | |
307 | ((uint32_t) bit_reverse_u8(v >> 16) << 8) | | |
308 | ((uint32_t) bit_reverse_u8(v >> 24)); | |
309 | } | |
310 | ||
311 | static __attribute__((unused)) | |
312 | uint64_t bit_reverse_u64(uint64_t v) | |
313 | { | |
314 | return ((uint64_t) bit_reverse_u8(v) << 56) | | |
315 | ((uint64_t) bit_reverse_u8(v >> 8) << 48) | | |
316 | ((uint64_t) bit_reverse_u8(v >> 16) << 40) | | |
317 | ((uint64_t) bit_reverse_u8(v >> 24) << 32) | | |
318 | ((uint64_t) bit_reverse_u8(v >> 32) << 24) | | |
319 | ((uint64_t) bit_reverse_u8(v >> 40) << 16) | | |
320 | ((uint64_t) bit_reverse_u8(v >> 48) << 8) | | |
321 | ((uint64_t) bit_reverse_u8(v >> 56)); | |
322 | } | |
323 | ||
324 | static | |
325 | unsigned long bit_reverse_ulong(unsigned long v) | |
326 | { | |
327 | #if (CAA_BITS_PER_LONG == 32) | |
328 | return bit_reverse_u32(v); | |
329 | #else | |
330 | return bit_reverse_u64(v); | |
331 | #endif | |
332 | } | |
333 | ||
334 | /* | |
335 | * fls: returns the position of the most significant bit. | |
336 | * Returns 0 if no bit is set, else returns the position of the most | |
337 | * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit). | |
338 | */ | |
339 | #if defined(__i386) || defined(__x86_64) | |
340 | static inline | |
341 | unsigned int fls_u32(uint32_t x) | |
342 | { | |
343 | int r; | |
344 | ||
345 | asm("bsrl %1,%0\n\t" | |
346 | "jnz 1f\n\t" | |
347 | "movl $-1,%0\n\t" | |
348 | "1:\n\t" | |
349 | : "=r" (r) : "rm" (x)); | |
350 | return r + 1; | |
351 | } | |
352 | #define HAS_FLS_U32 | |
353 | #endif | |
354 | ||
355 | #if defined(__x86_64) | |
356 | static inline | |
357 | unsigned int fls_u64(uint64_t x) | |
358 | { | |
359 | long r; | |
360 | ||
361 | asm("bsrq %1,%0\n\t" | |
362 | "jnz 1f\n\t" | |
363 | "movq $-1,%0\n\t" | |
364 | "1:\n\t" | |
365 | : "=r" (r) : "rm" (x)); | |
366 | return r + 1; | |
367 | } | |
368 | #define HAS_FLS_U64 | |
369 | #endif | |
370 | ||
371 | #ifndef HAS_FLS_U64 | |
372 | static __attribute__((unused)) | |
373 | unsigned int fls_u64(uint64_t x) | |
374 | { | |
375 | unsigned int r = 64; | |
376 | ||
377 | if (!x) | |
378 | return 0; | |
379 | ||
380 | if (!(x & 0xFFFFFFFF00000000ULL)) { | |
381 | x <<= 32; | |
382 | r -= 32; | |
383 | } | |
384 | if (!(x & 0xFFFF000000000000ULL)) { | |
385 | x <<= 16; | |
386 | r -= 16; | |
387 | } | |
388 | if (!(x & 0xFF00000000000000ULL)) { | |
389 | x <<= 8; | |
390 | r -= 8; | |
391 | } | |
392 | if (!(x & 0xF000000000000000ULL)) { | |
393 | x <<= 4; | |
394 | r -= 4; | |
395 | } | |
396 | if (!(x & 0xC000000000000000ULL)) { | |
397 | x <<= 2; | |
398 | r -= 2; | |
399 | } | |
400 | if (!(x & 0x8000000000000000ULL)) { | |
401 | x <<= 1; | |
402 | r -= 1; | |
403 | } | |
404 | return r; | |
405 | } | |
406 | #endif | |
407 | ||
408 | #ifndef HAS_FLS_U32 | |
409 | static __attribute__((unused)) | |
410 | unsigned int fls_u32(uint32_t x) | |
411 | { | |
412 | unsigned int r = 32; | |
413 | ||
414 | if (!x) | |
415 | return 0; | |
416 | if (!(x & 0xFFFF0000U)) { | |
417 | x <<= 16; | |
418 | r -= 16; | |
419 | } | |
420 | if (!(x & 0xFF000000U)) { | |
421 | x <<= 8; | |
422 | r -= 8; | |
423 | } | |
424 | if (!(x & 0xF0000000U)) { | |
425 | x <<= 4; | |
426 | r -= 4; | |
427 | } | |
428 | if (!(x & 0xC0000000U)) { | |
429 | x <<= 2; | |
430 | r -= 2; | |
431 | } | |
432 | if (!(x & 0x80000000U)) { | |
433 | x <<= 1; | |
434 | r -= 1; | |
435 | } | |
436 | return r; | |
437 | } | |
438 | #endif | |
439 | ||
440 | unsigned int fls_ulong(unsigned long x) | |
441 | { | |
442 | #if (CAA_BITS_PER_lONG == 32) | |
443 | return fls_u32(x); | |
444 | #else | |
445 | return fls_u64(x); | |
446 | #endif | |
447 | } | |
448 | ||
449 | int get_count_order_u32(uint32_t x) | |
450 | { | |
451 | int order; | |
452 | ||
453 | order = fls_u32(x) - 1; | |
454 | if (x & (x - 1)) | |
455 | order++; | |
456 | return order; | |
457 | } | |
458 | ||
459 | int get_count_order_ulong(unsigned long x) | |
460 | { | |
461 | int order; | |
462 | ||
463 | order = fls_ulong(x) - 1; | |
464 | if (x & (x - 1)) | |
465 | order++; | |
466 | return order; | |
467 | } | |
468 | ||
469 | #ifdef POISON_FREE | |
470 | #define poison_free(ptr) \ | |
471 | do { \ | |
472 | memset(ptr, 0x42, sizeof(*(ptr))); \ | |
473 | free(ptr); \ | |
474 | } while (0) | |
475 | #else | |
476 | #define poison_free(ptr) free(ptr) | |
477 | #endif | |
478 | ||
479 | static | |
480 | void cds_lfht_resize_lazy(struct cds_lfht *ht, unsigned long size, int growth); | |
481 | ||
482 | /* | |
483 | * If the sched_getcpu() and sysconf(_SC_NPROCESSORS_CONF) calls are | |
484 | * available, then we support hash table item accounting. | |
485 | * In the unfortunate event the number of CPUs reported would be | |
486 | * inaccurate, we use modulo arithmetic on the number of CPUs we got. | |
487 | */ | |
488 | #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) | |
489 | ||
490 | static | |
491 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, | |
492 | unsigned long count); | |
493 | ||
494 | static long nr_cpus_mask = -1; | |
495 | ||
496 | static | |
497 | struct ht_items_count *alloc_per_cpu_items_count(void) | |
498 | { | |
499 | struct ht_items_count *count; | |
500 | ||
501 | switch (nr_cpus_mask) { | |
502 | case -2: | |
503 | return NULL; | |
504 | case -1: | |
505 | { | |
506 | long maxcpus; | |
507 | ||
508 | maxcpus = sysconf(_SC_NPROCESSORS_CONF); | |
509 | if (maxcpus <= 0) { | |
510 | nr_cpus_mask = -2; | |
511 | return NULL; | |
512 | } | |
513 | /* | |
514 | * round up number of CPUs to next power of two, so we | |
515 | * can use & for modulo. | |
516 | */ | |
517 | maxcpus = 1UL << get_count_order_ulong(maxcpus); | |
518 | nr_cpus_mask = maxcpus - 1; | |
519 | } | |
520 | /* Fall-through */ | |
521 | default: | |
522 | return calloc(nr_cpus_mask + 1, sizeof(*count)); | |
523 | } | |
524 | } | |
525 | ||
526 | static | |
527 | void free_per_cpu_items_count(struct ht_items_count *count) | |
528 | { | |
529 | poison_free(count); | |
530 | } | |
531 | ||
532 | static | |
533 | int ht_get_cpu(void) | |
534 | { | |
535 | int cpu; | |
536 | ||
537 | assert(nr_cpus_mask >= 0); | |
538 | cpu = sched_getcpu(); | |
539 | if (unlikely(cpu < 0)) | |
540 | return cpu; | |
541 | else | |
542 | return cpu & nr_cpus_mask; | |
543 | } | |
544 | ||
545 | static | |
546 | void ht_count_add(struct cds_lfht *ht, unsigned long size) | |
547 | { | |
548 | unsigned long percpu_count; | |
549 | int cpu; | |
550 | ||
551 | if (unlikely(!ht->percpu_count)) | |
552 | return; | |
553 | cpu = ht_get_cpu(); | |
554 | if (unlikely(cpu < 0)) | |
555 | return; | |
556 | percpu_count = uatomic_add_return(&ht->percpu_count[cpu].add, 1); | |
557 | if (unlikely(!(percpu_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) { | |
558 | long count; | |
559 | ||
560 | dbg_printf("add percpu %lu\n", percpu_count); | |
561 | count = uatomic_add_return(&ht->count, | |
562 | 1UL << COUNT_COMMIT_ORDER); | |
563 | /* If power of 2 */ | |
564 | if (!(count & (count - 1))) { | |
565 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) < size) | |
566 | return; | |
567 | dbg_printf("add set global %ld\n", count); | |
568 | cds_lfht_resize_lazy_count(ht, size, | |
569 | count >> (CHAIN_LEN_TARGET - 1)); | |
570 | } | |
571 | } | |
572 | } | |
573 | ||
574 | static | |
575 | void ht_count_del(struct cds_lfht *ht, unsigned long size) | |
576 | { | |
577 | unsigned long percpu_count; | |
578 | int cpu; | |
579 | ||
580 | if (unlikely(!ht->percpu_count)) | |
581 | return; | |
582 | cpu = ht_get_cpu(); | |
583 | if (unlikely(cpu < 0)) | |
584 | return; | |
585 | percpu_count = uatomic_add_return(&ht->percpu_count[cpu].del, 1); | |
586 | if (unlikely(!(percpu_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) { | |
587 | long count; | |
588 | ||
589 | dbg_printf("del percpu %lu\n", percpu_count); | |
590 | count = uatomic_add_return(&ht->count, | |
591 | -(1UL << COUNT_COMMIT_ORDER)); | |
592 | /* If power of 2 */ | |
593 | if (!(count & (count - 1))) { | |
594 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) >= size) | |
595 | return; | |
596 | dbg_printf("del set global %ld\n", count); | |
597 | /* | |
598 | * Don't shrink table if the number of nodes is below a | |
599 | * certain threshold. | |
600 | */ | |
601 | if (count < (1UL << COUNT_COMMIT_ORDER) * (nr_cpus_mask + 1)) | |
602 | return; | |
603 | cds_lfht_resize_lazy_count(ht, size, | |
604 | count >> (CHAIN_LEN_TARGET - 1)); | |
605 | } | |
606 | } | |
607 | } | |
608 | ||
609 | #else /* #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */ | |
610 | ||
f6a9efaa | 611 | static const long nr_cpus_mask = -2; |
fa68aa62 MD |
612 | |
613 | static | |
614 | struct ht_items_count *alloc_per_cpu_items_count(void) | |
615 | { | |
616 | return NULL; | |
617 | } | |
618 | ||
619 | static | |
620 | void free_per_cpu_items_count(struct ht_items_count *count) | |
621 | { | |
622 | } | |
623 | ||
624 | static | |
625 | void ht_count_add(struct cds_lfht *ht, unsigned long size) | |
626 | { | |
627 | } | |
628 | ||
629 | static | |
630 | void ht_count_del(struct cds_lfht *ht, unsigned long size) | |
631 | { | |
632 | } | |
633 | ||
634 | #endif /* #else #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */ | |
635 | ||
636 | ||
637 | static | |
638 | void check_resize(struct cds_lfht *ht, unsigned long size, uint32_t chain_len) | |
639 | { | |
640 | unsigned long count; | |
641 | ||
642 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) | |
643 | return; | |
644 | count = uatomic_read(&ht->count); | |
645 | /* | |
646 | * Use bucket-local length for small table expand and for | |
647 | * environments lacking per-cpu data support. | |
648 | */ | |
649 | if (count >= (1UL << COUNT_COMMIT_ORDER)) | |
650 | return; | |
651 | if (chain_len > 100) | |
652 | dbg_printf("WARNING: large chain length: %u.\n", | |
653 | chain_len); | |
654 | if (chain_len >= CHAIN_LEN_RESIZE_THRESHOLD) | |
655 | cds_lfht_resize_lazy(ht, size, | |
656 | get_count_order_u32(chain_len - (CHAIN_LEN_TARGET - 1))); | |
657 | } | |
658 | ||
659 | static | |
660 | struct cds_lfht_node *clear_flag(struct cds_lfht_node *node) | |
661 | { | |
662 | return (struct cds_lfht_node *) (((unsigned long) node) & ~FLAGS_MASK); | |
663 | } | |
664 | ||
665 | static | |
666 | int is_removed(struct cds_lfht_node *node) | |
667 | { | |
668 | return ((unsigned long) node) & REMOVED_FLAG; | |
669 | } | |
670 | ||
671 | static | |
672 | struct cds_lfht_node *flag_removed(struct cds_lfht_node *node) | |
673 | { | |
674 | return (struct cds_lfht_node *) (((unsigned long) node) | REMOVED_FLAG); | |
675 | } | |
676 | ||
677 | static | |
678 | int is_dummy(struct cds_lfht_node *node) | |
679 | { | |
680 | return ((unsigned long) node) & DUMMY_FLAG; | |
681 | } | |
682 | ||
683 | static | |
684 | struct cds_lfht_node *flag_dummy(struct cds_lfht_node *node) | |
685 | { | |
686 | return (struct cds_lfht_node *) (((unsigned long) node) | DUMMY_FLAG); | |
687 | } | |
688 | ||
689 | static | |
690 | struct cds_lfht_node *get_end(void) | |
691 | { | |
692 | return (struct cds_lfht_node *) END_VALUE; | |
693 | } | |
694 | ||
695 | static | |
696 | int is_end(struct cds_lfht_node *node) | |
697 | { | |
698 | return clear_flag(node) == (struct cds_lfht_node *) END_VALUE; | |
699 | } | |
700 | ||
701 | static | |
702 | unsigned long _uatomic_max(unsigned long *ptr, unsigned long v) | |
703 | { | |
704 | unsigned long old1, old2; | |
705 | ||
706 | old1 = uatomic_read(ptr); | |
707 | do { | |
708 | old2 = old1; | |
709 | if (old2 >= v) | |
710 | return old2; | |
711 | } while ((old1 = uatomic_cmpxchg(ptr, old2, v)) != old2); | |
712 | return v; | |
713 | } | |
714 | ||
715 | static | |
716 | void cds_lfht_free_level(struct rcu_head *head) | |
717 | { | |
718 | struct rcu_level *l = | |
719 | caa_container_of(head, struct rcu_level, head); | |
720 | poison_free(l); | |
721 | } | |
722 | ||
723 | /* | |
724 | * Remove all logically deleted nodes from a bucket up to a certain node key. | |
725 | */ | |
726 | static | |
727 | void _cds_lfht_gc_bucket(struct cds_lfht_node *dummy, struct cds_lfht_node *node) | |
728 | { | |
729 | struct cds_lfht_node *iter_prev, *iter, *next, *new_next; | |
730 | ||
731 | assert(!is_dummy(dummy)); | |
732 | assert(!is_removed(dummy)); | |
733 | assert(!is_dummy(node)); | |
734 | assert(!is_removed(node)); | |
735 | for (;;) { | |
736 | iter_prev = dummy; | |
737 | /* We can always skip the dummy node initially */ | |
738 | iter = rcu_dereference(iter_prev->p.next); | |
739 | assert(iter_prev->p.reverse_hash <= node->p.reverse_hash); | |
740 | /* | |
741 | * We should never be called with dummy (start of chain) | |
742 | * and logically removed node (end of path compression | |
743 | * marker) being the actual same node. This would be a | |
744 | * bug in the algorithm implementation. | |
745 | */ | |
746 | assert(dummy != node); | |
747 | for (;;) { | |
748 | if (unlikely(is_end(iter))) | |
749 | return; | |
750 | if (likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash)) | |
751 | return; | |
752 | next = rcu_dereference(clear_flag(iter)->p.next); | |
753 | if (likely(is_removed(next))) | |
754 | break; | |
755 | iter_prev = clear_flag(iter); | |
756 | iter = next; | |
757 | } | |
758 | assert(!is_removed(iter)); | |
759 | if (is_dummy(iter)) | |
760 | new_next = flag_dummy(clear_flag(next)); | |
761 | else | |
762 | new_next = clear_flag(next); | |
763 | if (is_removed(iter)) | |
764 | new_next = flag_removed(new_next); | |
765 | (void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next); | |
766 | } | |
767 | return; | |
768 | } | |
769 | ||
770 | static | |
771 | int _cds_lfht_replace(struct cds_lfht *ht, unsigned long size, | |
772 | struct cds_lfht_node *old_node, | |
773 | struct cds_lfht_node *ret_next, | |
774 | struct cds_lfht_node *new_node) | |
775 | { | |
776 | struct cds_lfht_node *dummy, *old_next; | |
777 | struct _cds_lfht_node *lookup; | |
778 | int flagged = 0; | |
779 | unsigned long hash, index, order; | |
780 | ||
781 | if (!old_node) /* Return -ENOENT if asked to replace NULL node */ | |
782 | goto end; | |
783 | ||
784 | assert(!is_removed(old_node)); | |
785 | assert(!is_dummy(old_node)); | |
786 | assert(!is_removed(new_node)); | |
787 | assert(!is_dummy(new_node)); | |
788 | assert(new_node != old_node); | |
789 | do { | |
790 | /* Insert after node to be replaced */ | |
791 | old_next = ret_next; | |
792 | if (is_removed(old_next)) { | |
793 | /* | |
794 | * Too late, the old node has been removed under us | |
795 | * between lookup and replace. Fail. | |
796 | */ | |
797 | goto end; | |
798 | } | |
799 | assert(!is_dummy(old_next)); | |
800 | assert(new_node != clear_flag(old_next)); | |
801 | new_node->p.next = clear_flag(old_next); | |
802 | /* | |
803 | * Here is the whole trick for lock-free replace: we add | |
804 | * the replacement node _after_ the node we want to | |
805 | * replace by atomically setting its next pointer at the | |
806 | * same time we set its removal flag. Given that | |
807 | * the lookups/get next use an iterator aware of the | |
808 | * next pointer, they will either skip the old node due | |
809 | * to the removal flag and see the new node, or use | |
810 | * the old node, but will not see the new one. | |
811 | */ | |
812 | ret_next = uatomic_cmpxchg(&old_node->p.next, | |
813 | old_next, flag_removed(new_node)); | |
814 | } while (ret_next != old_next); | |
815 | ||
816 | /* We performed the replacement. */ | |
817 | flagged = 1; | |
818 | ||
819 | /* | |
820 | * Ensure that the old node is not visible to readers anymore: | |
821 | * lookup for the node, and remove it (along with any other | |
822 | * logically removed node) if found. | |
823 | */ | |
824 | hash = bit_reverse_ulong(old_node->p.reverse_hash); | |
825 | assert(size > 0); | |
826 | index = hash & (size - 1); | |
827 | order = get_count_order_ulong(index + 1); | |
828 | lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1)) - 1))]; | |
829 | dummy = (struct cds_lfht_node *) lookup; | |
830 | _cds_lfht_gc_bucket(dummy, new_node); | |
831 | end: | |
832 | /* | |
833 | * Only the flagging action indicated that we (and no other) | |
834 | * replaced the node from the hash table. | |
835 | */ | |
836 | if (flagged) { | |
837 | assert(is_removed(rcu_dereference(old_node->p.next))); | |
838 | return 0; | |
839 | } else { | |
840 | return -ENOENT; | |
841 | } | |
842 | } | |
843 | ||
844 | static | |
845 | struct cds_lfht_node *_cds_lfht_add(struct cds_lfht *ht, | |
846 | unsigned long size, | |
847 | struct cds_lfht_node *node, | |
848 | enum add_mode mode, int dummy) | |
849 | { | |
850 | struct cds_lfht_node *iter_prev, *iter, *next, *new_node, *new_next, | |
851 | *dummy_node, *return_node; | |
852 | struct _cds_lfht_node *lookup; | |
853 | unsigned long hash, index, order; | |
854 | ||
855 | assert(!is_dummy(node)); | |
856 | assert(!is_removed(node)); | |
857 | if (!size) { | |
858 | assert(dummy); | |
859 | node->p.next = flag_dummy(get_end()); | |
860 | return node; /* Initial first add (head) */ | |
861 | } | |
862 | hash = bit_reverse_ulong(node->p.reverse_hash); | |
863 | for (;;) { | |
864 | uint32_t chain_len = 0; | |
865 | ||
866 | /* | |
867 | * iter_prev points to the non-removed node prior to the | |
868 | * insert location. | |
869 | */ | |
870 | index = hash & (size - 1); | |
871 | order = get_count_order_ulong(index + 1); | |
872 | lookup = &ht->t.tbl[order]->nodes[index & ((!order ? 0 : (1UL << (order - 1))) - 1)]; | |
873 | iter_prev = (struct cds_lfht_node *) lookup; | |
874 | /* We can always skip the dummy node initially */ | |
875 | iter = rcu_dereference(iter_prev->p.next); | |
876 | assert(iter_prev->p.reverse_hash <= node->p.reverse_hash); | |
877 | for (;;) { | |
878 | if (unlikely(is_end(iter))) | |
879 | goto insert; | |
880 | if (likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash)) | |
881 | goto insert; | |
882 | next = rcu_dereference(clear_flag(iter)->p.next); | |
883 | if (unlikely(is_removed(next))) | |
884 | goto gc_node; | |
885 | if ((mode == ADD_UNIQUE || mode == ADD_REPLACE) | |
886 | && !is_dummy(next) | |
887 | && !ht->compare_fct(node->key, node->key_len, | |
888 | clear_flag(iter)->key, | |
889 | clear_flag(iter)->key_len)) { | |
890 | if (mode == ADD_UNIQUE) | |
891 | return clear_flag(iter); | |
892 | else /* mode == ADD_REPLACE */ | |
893 | goto replace; | |
894 | } | |
895 | /* Only account for identical reverse hash once */ | |
896 | if (iter_prev->p.reverse_hash != clear_flag(iter)->p.reverse_hash | |
897 | && !is_dummy(next)) | |
898 | check_resize(ht, size, ++chain_len); | |
899 | iter_prev = clear_flag(iter); | |
900 | iter = next; | |
901 | } | |
902 | ||
903 | insert: | |
904 | assert(node != clear_flag(iter)); | |
905 | assert(!is_removed(iter_prev)); | |
906 | assert(!is_removed(iter)); | |
907 | assert(iter_prev != node); | |
908 | if (!dummy) | |
909 | node->p.next = clear_flag(iter); | |
910 | else | |
911 | node->p.next = flag_dummy(clear_flag(iter)); | |
912 | if (is_dummy(iter)) | |
913 | new_node = flag_dummy(node); | |
914 | else | |
915 | new_node = node; | |
916 | if (uatomic_cmpxchg(&iter_prev->p.next, iter, | |
917 | new_node) != iter) { | |
918 | continue; /* retry */ | |
919 | } else { | |
920 | if (mode == ADD_REPLACE) | |
921 | return_node = NULL; | |
922 | else /* ADD_DEFAULT and ADD_UNIQUE */ | |
923 | return_node = node; | |
924 | goto gc_end; | |
925 | } | |
926 | ||
927 | replace: | |
928 | ||
929 | if (!_cds_lfht_replace(ht, size, clear_flag(iter), next, | |
930 | node)) { | |
931 | return_node = clear_flag(iter); | |
932 | goto end; /* gc already done */ | |
933 | } else { | |
934 | continue; /* retry */ | |
935 | } | |
936 | ||
937 | gc_node: | |
938 | assert(!is_removed(iter)); | |
939 | if (is_dummy(iter)) | |
940 | new_next = flag_dummy(clear_flag(next)); | |
941 | else | |
942 | new_next = clear_flag(next); | |
943 | (void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next); | |
944 | /* retry */ | |
945 | } | |
946 | gc_end: | |
947 | /* Garbage collect logically removed nodes in the bucket */ | |
948 | index = hash & (size - 1); | |
949 | order = get_count_order_ulong(index + 1); | |
950 | lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1)) - 1))]; | |
951 | dummy_node = (struct cds_lfht_node *) lookup; | |
952 | _cds_lfht_gc_bucket(dummy_node, node); | |
953 | end: | |
954 | return return_node; | |
955 | } | |
956 | ||
957 | static | |
958 | int _cds_lfht_del(struct cds_lfht *ht, unsigned long size, | |
959 | struct cds_lfht_node *node, | |
960 | int dummy_removal) | |
961 | { | |
962 | struct cds_lfht_node *dummy, *next, *old; | |
963 | struct _cds_lfht_node *lookup; | |
964 | int flagged = 0; | |
965 | unsigned long hash, index, order; | |
966 | ||
967 | if (!node) /* Return -ENOENT if asked to delete NULL node */ | |
968 | goto end; | |
969 | ||
970 | /* logically delete the node */ | |
971 | assert(!is_dummy(node)); | |
972 | assert(!is_removed(node)); | |
973 | old = rcu_dereference(node->p.next); | |
974 | do { | |
975 | struct cds_lfht_node *new_next; | |
976 | ||
977 | next = old; | |
978 | if (unlikely(is_removed(next))) | |
979 | goto end; | |
980 | if (dummy_removal) | |
981 | assert(is_dummy(next)); | |
982 | else | |
983 | assert(!is_dummy(next)); | |
984 | new_next = flag_removed(next); | |
985 | old = uatomic_cmpxchg(&node->p.next, next, new_next); | |
986 | } while (old != next); | |
987 | ||
988 | /* We performed the (logical) deletion. */ | |
989 | flagged = 1; | |
990 | ||
991 | /* | |
992 | * Ensure that the node is not visible to readers anymore: lookup for | |
993 | * the node, and remove it (along with any other logically removed node) | |
994 | * if found. | |
995 | */ | |
996 | hash = bit_reverse_ulong(node->p.reverse_hash); | |
997 | assert(size > 0); | |
998 | index = hash & (size - 1); | |
999 | order = get_count_order_ulong(index + 1); | |
1000 | lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1)) - 1))]; | |
1001 | dummy = (struct cds_lfht_node *) lookup; | |
1002 | _cds_lfht_gc_bucket(dummy, node); | |
1003 | end: | |
1004 | /* | |
1005 | * Only the flagging action indicated that we (and no other) | |
1006 | * removed the node from the hash. | |
1007 | */ | |
1008 | if (flagged) { | |
1009 | assert(is_removed(rcu_dereference(node->p.next))); | |
1010 | return 0; | |
1011 | } else { | |
1012 | return -ENOENT; | |
1013 | } | |
1014 | } | |
1015 | ||
1016 | static | |
1017 | void *partition_resize_thread(void *arg) | |
1018 | { | |
1019 | struct partition_resize_work *work = arg; | |
1020 | ||
1021 | work->ht->cds_lfht_rcu_register_thread(); | |
1022 | work->fct(work->ht, work->i, work->start, work->len); | |
1023 | work->ht->cds_lfht_rcu_unregister_thread(); | |
1024 | return NULL; | |
1025 | } | |
1026 | ||
1027 | static | |
1028 | void partition_resize_helper(struct cds_lfht *ht, unsigned long i, | |
1029 | unsigned long len, | |
1030 | void (*fct)(struct cds_lfht *ht, unsigned long i, | |
1031 | unsigned long start, unsigned long len)) | |
1032 | { | |
1033 | unsigned long partition_len; | |
1034 | struct partition_resize_work *work; | |
1035 | int thread, ret; | |
1036 | unsigned long nr_threads; | |
1037 | pthread_t *thread_id; | |
1038 | ||
1039 | /* | |
1040 | * Note: nr_cpus_mask + 1 is always power of 2. | |
1041 | * We spawn just the number of threads we need to satisfy the minimum | |
1042 | * partition size, up to the number of CPUs in the system. | |
1043 | */ | |
f6a9efaa DG |
1044 | if (nr_cpus_mask > 0) { |
1045 | nr_threads = min(nr_cpus_mask + 1, | |
1046 | len >> MIN_PARTITION_PER_THREAD_ORDER); | |
1047 | } else { | |
1048 | nr_threads = 1; | |
1049 | } | |
fa68aa62 MD |
1050 | partition_len = len >> get_count_order_ulong(nr_threads); |
1051 | work = calloc(nr_threads, sizeof(*work)); | |
1052 | thread_id = calloc(nr_threads, sizeof(*thread_id)); | |
1053 | assert(work); | |
1054 | for (thread = 0; thread < nr_threads; thread++) { | |
1055 | work[thread].ht = ht; | |
1056 | work[thread].i = i; | |
1057 | work[thread].len = partition_len; | |
1058 | work[thread].start = thread * partition_len; | |
1059 | work[thread].fct = fct; | |
1060 | ret = pthread_create(&thread_id[thread], ht->resize_attr, | |
1061 | partition_resize_thread, &work[thread]); | |
1062 | assert(!ret); | |
1063 | } | |
1064 | for (thread = 0; thread < nr_threads; thread++) { | |
1065 | ret = pthread_join(thread_id[thread], NULL); | |
1066 | assert(!ret); | |
1067 | } | |
1068 | free(work); | |
1069 | free(thread_id); | |
1070 | } | |
1071 | ||
1072 | /* | |
1073 | * Holding RCU read lock to protect _cds_lfht_add against memory | |
1074 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
1075 | * problem). | |
1076 | * | |
1077 | * When we reach a certain length, we can split this population phase over | |
1078 | * many worker threads, based on the number of CPUs available in the system. | |
1079 | * This should therefore take care of not having the expand lagging behind too | |
1080 | * many concurrent insertion threads by using the scheduler's ability to | |
1081 | * schedule dummy node population fairly with insertions. | |
1082 | */ | |
1083 | static | |
1084 | void init_table_populate_partition(struct cds_lfht *ht, unsigned long i, | |
1085 | unsigned long start, unsigned long len) | |
1086 | { | |
1087 | unsigned long j; | |
1088 | ||
1089 | ht->cds_lfht_rcu_read_lock(); | |
1090 | for (j = start; j < start + len; j++) { | |
1091 | struct cds_lfht_node *new_node = | |
1092 | (struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j]; | |
1093 | ||
1094 | dbg_printf("init populate: i %lu j %lu hash %lu\n", | |
1095 | i, j, !i ? 0 : (1UL << (i - 1)) + j); | |
1096 | new_node->p.reverse_hash = | |
1097 | bit_reverse_ulong(!i ? 0 : (1UL << (i - 1)) + j); | |
1098 | (void) _cds_lfht_add(ht, !i ? 0 : (1UL << (i - 1)), | |
1099 | new_node, ADD_DEFAULT, 1); | |
1100 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
1101 | break; | |
1102 | } | |
1103 | ht->cds_lfht_rcu_read_unlock(); | |
1104 | } | |
1105 | ||
1106 | static | |
1107 | void init_table_populate(struct cds_lfht *ht, unsigned long i, | |
1108 | unsigned long len) | |
1109 | { | |
1110 | assert(nr_cpus_mask != -1); | |
1111 | if (nr_cpus_mask < 0 || len < 2 * MIN_PARTITION_PER_THREAD) { | |
1112 | ht->cds_lfht_rcu_thread_online(); | |
1113 | init_table_populate_partition(ht, i, 0, len); | |
1114 | ht->cds_lfht_rcu_thread_offline(); | |
1115 | return; | |
1116 | } | |
1117 | partition_resize_helper(ht, i, len, init_table_populate_partition); | |
1118 | } | |
1119 | ||
1120 | static | |
1121 | void init_table(struct cds_lfht *ht, | |
1122 | unsigned long first_order, unsigned long len_order) | |
1123 | { | |
1124 | unsigned long i, end_order; | |
1125 | ||
1126 | dbg_printf("init table: first_order %lu end_order %lu\n", | |
1127 | first_order, first_order + len_order); | |
1128 | end_order = first_order + len_order; | |
1129 | for (i = first_order; i < end_order; i++) { | |
1130 | unsigned long len; | |
1131 | ||
1132 | len = !i ? 1 : 1UL << (i - 1); | |
1133 | dbg_printf("init order %lu len: %lu\n", i, len); | |
1134 | ||
1135 | /* Stop expand if the resize target changes under us */ | |
1136 | if (CMM_LOAD_SHARED(ht->t.resize_target) < (!i ? 1 : (1UL << i))) | |
1137 | break; | |
1138 | ||
1139 | ht->t.tbl[i] = calloc(1, sizeof(struct rcu_level) | |
1140 | + (len * sizeof(struct _cds_lfht_node))); | |
1141 | assert(ht->t.tbl[i]); | |
1142 | ||
1143 | /* | |
1144 | * Set all dummy nodes reverse hash values for a level and | |
1145 | * link all dummy nodes into the table. | |
1146 | */ | |
1147 | init_table_populate(ht, i, len); | |
1148 | ||
1149 | /* | |
1150 | * Update table size. | |
1151 | */ | |
1152 | cmm_smp_wmb(); /* populate data before RCU size */ | |
1153 | CMM_STORE_SHARED(ht->t.size, !i ? 1 : (1UL << i)); | |
1154 | ||
1155 | dbg_printf("init new size: %lu\n", !i ? 1 : (1UL << i)); | |
1156 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
1157 | break; | |
1158 | } | |
1159 | } | |
1160 | ||
1161 | /* | |
1162 | * Holding RCU read lock to protect _cds_lfht_remove against memory | |
1163 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
1164 | * problem). | |
1165 | * For a single level, we logically remove and garbage collect each node. | |
1166 | * | |
1167 | * As a design choice, we perform logical removal and garbage collection on a | |
1168 | * node-per-node basis to simplify this algorithm. We also assume keeping good | |
1169 | * cache locality of the operation would overweight possible performance gain | |
1170 | * that could be achieved by batching garbage collection for multiple levels. | |
1171 | * However, this would have to be justified by benchmarks. | |
1172 | * | |
1173 | * Concurrent removal and add operations are helping us perform garbage | |
1174 | * collection of logically removed nodes. We guarantee that all logically | |
1175 | * removed nodes have been garbage-collected (unlinked) before call_rcu is | |
1176 | * invoked to free a hole level of dummy nodes (after a grace period). | |
1177 | * | |
1178 | * Logical removal and garbage collection can therefore be done in batch or on a | |
1179 | * node-per-node basis, as long as the guarantee above holds. | |
1180 | * | |
1181 | * When we reach a certain length, we can split this removal over many worker | |
1182 | * threads, based on the number of CPUs available in the system. This should | |
1183 | * take care of not letting resize process lag behind too many concurrent | |
1184 | * updater threads actively inserting into the hash table. | |
1185 | */ | |
1186 | static | |
1187 | void remove_table_partition(struct cds_lfht *ht, unsigned long i, | |
1188 | unsigned long start, unsigned long len) | |
1189 | { | |
1190 | unsigned long j; | |
1191 | ||
1192 | ht->cds_lfht_rcu_read_lock(); | |
1193 | for (j = start; j < start + len; j++) { | |
1194 | struct cds_lfht_node *fini_node = | |
1195 | (struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j]; | |
1196 | ||
1197 | dbg_printf("remove entry: i %lu j %lu hash %lu\n", | |
1198 | i, j, !i ? 0 : (1UL << (i - 1)) + j); | |
1199 | fini_node->p.reverse_hash = | |
1200 | bit_reverse_ulong(!i ? 0 : (1UL << (i - 1)) + j); | |
1201 | (void) _cds_lfht_del(ht, !i ? 0 : (1UL << (i - 1)), | |
1202 | fini_node, 1); | |
1203 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
1204 | break; | |
1205 | } | |
1206 | ht->cds_lfht_rcu_read_unlock(); | |
1207 | } | |
1208 | ||
1209 | static | |
1210 | void remove_table(struct cds_lfht *ht, unsigned long i, unsigned long len) | |
1211 | { | |
1212 | ||
1213 | assert(nr_cpus_mask != -1); | |
1214 | if (nr_cpus_mask < 0 || len < 2 * MIN_PARTITION_PER_THREAD) { | |
1215 | ht->cds_lfht_rcu_thread_online(); | |
1216 | remove_table_partition(ht, i, 0, len); | |
1217 | ht->cds_lfht_rcu_thread_offline(); | |
1218 | return; | |
1219 | } | |
1220 | partition_resize_helper(ht, i, len, remove_table_partition); | |
1221 | } | |
1222 | ||
1223 | static | |
1224 | void fini_table(struct cds_lfht *ht, | |
1225 | unsigned long first_order, unsigned long len_order) | |
1226 | { | |
1227 | long i, end_order; | |
1228 | ||
1229 | dbg_printf("fini table: first_order %lu end_order %lu\n", | |
1230 | first_order, first_order + len_order); | |
1231 | end_order = first_order + len_order; | |
1232 | assert(first_order > 0); | |
1233 | for (i = end_order - 1; i >= first_order; i--) { | |
1234 | unsigned long len; | |
1235 | ||
1236 | len = !i ? 1 : 1UL << (i - 1); | |
1237 | dbg_printf("fini order %lu len: %lu\n", i, len); | |
1238 | ||
1239 | /* Stop shrink if the resize target changes under us */ | |
1240 | if (CMM_LOAD_SHARED(ht->t.resize_target) > (1UL << (i - 1))) | |
1241 | break; | |
1242 | ||
1243 | cmm_smp_wmb(); /* populate data before RCU size */ | |
1244 | CMM_STORE_SHARED(ht->t.size, 1UL << (i - 1)); | |
1245 | ||
1246 | /* | |
1247 | * We need to wait for all add operations to reach Q.S. (and | |
1248 | * thus use the new table for lookups) before we can start | |
1249 | * releasing the old dummy nodes. Otherwise their lookup will | |
1250 | * return a logically removed node as insert position. | |
1251 | */ | |
1252 | ht->cds_lfht_synchronize_rcu(); | |
1253 | ||
1254 | /* | |
1255 | * Set "removed" flag in dummy nodes about to be removed. | |
1256 | * Unlink all now-logically-removed dummy node pointers. | |
1257 | * Concurrent add/remove operation are helping us doing | |
1258 | * the gc. | |
1259 | */ | |
1260 | remove_table(ht, i, len); | |
1261 | ||
1262 | ht->cds_lfht_call_rcu(&ht->t.tbl[i]->head, cds_lfht_free_level); | |
1263 | ||
1264 | dbg_printf("fini new size: %lu\n", 1UL << i); | |
1265 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
1266 | break; | |
1267 | } | |
1268 | } | |
1269 | ||
1270 | struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct, | |
1271 | cds_lfht_compare_fct compare_fct, | |
1272 | unsigned long hash_seed, | |
1273 | unsigned long init_size, | |
1274 | int flags, | |
1275 | void (*cds_lfht_call_rcu)(struct rcu_head *head, | |
1276 | void (*func)(struct rcu_head *head)), | |
1277 | void (*cds_lfht_synchronize_rcu)(void), | |
1278 | void (*cds_lfht_rcu_read_lock)(void), | |
1279 | void (*cds_lfht_rcu_read_unlock)(void), | |
1280 | void (*cds_lfht_rcu_thread_offline)(void), | |
1281 | void (*cds_lfht_rcu_thread_online)(void), | |
1282 | void (*cds_lfht_rcu_register_thread)(void), | |
1283 | void (*cds_lfht_rcu_unregister_thread)(void), | |
1284 | pthread_attr_t *attr) | |
1285 | { | |
1286 | struct cds_lfht *ht; | |
1287 | unsigned long order; | |
1288 | ||
1289 | /* init_size must be power of two */ | |
1290 | if (init_size && (init_size & (init_size - 1))) | |
1291 | return NULL; | |
1292 | ht = calloc(1, sizeof(struct cds_lfht)); | |
1293 | assert(ht); | |
1294 | ht->hash_fct = hash_fct; | |
1295 | ht->compare_fct = compare_fct; | |
1296 | ht->hash_seed = hash_seed; | |
1297 | ht->cds_lfht_call_rcu = cds_lfht_call_rcu; | |
1298 | ht->cds_lfht_synchronize_rcu = cds_lfht_synchronize_rcu; | |
1299 | ht->cds_lfht_rcu_read_lock = cds_lfht_rcu_read_lock; | |
1300 | ht->cds_lfht_rcu_read_unlock = cds_lfht_rcu_read_unlock; | |
1301 | ht->cds_lfht_rcu_thread_offline = cds_lfht_rcu_thread_offline; | |
1302 | ht->cds_lfht_rcu_thread_online = cds_lfht_rcu_thread_online; | |
1303 | ht->cds_lfht_rcu_register_thread = cds_lfht_rcu_register_thread; | |
1304 | ht->cds_lfht_rcu_unregister_thread = cds_lfht_rcu_unregister_thread; | |
1305 | ht->resize_attr = attr; | |
1306 | ht->percpu_count = alloc_per_cpu_items_count(); | |
1307 | /* this mutex should not nest in read-side C.S. */ | |
1308 | pthread_mutex_init(&ht->resize_mutex, NULL); | |
1309 | order = get_count_order_ulong(max(init_size, MIN_TABLE_SIZE)) + 1; | |
1310 | ht->flags = flags; | |
1311 | ht->cds_lfht_rcu_thread_offline(); | |
1312 | pthread_mutex_lock(&ht->resize_mutex); | |
1313 | ht->t.resize_target = 1UL << (order - 1); | |
1314 | init_table(ht, 0, order); | |
1315 | pthread_mutex_unlock(&ht->resize_mutex); | |
1316 | ht->cds_lfht_rcu_thread_online(); | |
1317 | return ht; | |
1318 | } | |
1319 | ||
1320 | void cds_lfht_lookup(struct cds_lfht *ht, void *key, size_t key_len, | |
1321 | struct cds_lfht_iter *iter) | |
1322 | { | |
1323 | struct cds_lfht_node *node, *next, *dummy_node; | |
1324 | struct _cds_lfht_node *lookup; | |
1325 | unsigned long hash, reverse_hash, index, order, size; | |
1326 | ||
1327 | hash = ht->hash_fct(key, key_len, ht->hash_seed); | |
1328 | reverse_hash = bit_reverse_ulong(hash); | |
1329 | ||
1330 | size = rcu_dereference(ht->t.size); | |
1331 | index = hash & (size - 1); | |
1332 | order = get_count_order_ulong(index + 1); | |
1333 | lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1))) - 1)]; | |
1334 | dbg_printf("lookup hash %lu index %lu order %lu aridx %lu\n", | |
1335 | hash, index, order, index & (!order ? 0 : ((1UL << (order - 1)) - 1))); | |
1336 | dummy_node = (struct cds_lfht_node *) lookup; | |
1337 | /* We can always skip the dummy node initially */ | |
1338 | node = rcu_dereference(dummy_node->p.next); | |
1339 | node = clear_flag(node); | |
1340 | for (;;) { | |
1341 | if (unlikely(is_end(node))) { | |
1342 | node = next = NULL; | |
1343 | break; | |
1344 | } | |
1345 | if (unlikely(node->p.reverse_hash > reverse_hash)) { | |
1346 | node = next = NULL; | |
1347 | break; | |
1348 | } | |
1349 | next = rcu_dereference(node->p.next); | |
1350 | if (likely(!is_removed(next)) | |
1351 | && !is_dummy(next) | |
1352 | && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) { | |
1353 | break; | |
1354 | } | |
1355 | node = clear_flag(next); | |
1356 | } | |
1357 | assert(!node || !is_dummy(rcu_dereference(node->p.next))); | |
1358 | iter->node = node; | |
1359 | iter->next = next; | |
1360 | } | |
1361 | ||
f6a9efaa | 1362 | void cds_lfht_next_duplicate(struct cds_lfht *ht, struct cds_lfht_iter *iter) |
fa68aa62 MD |
1363 | { |
1364 | struct cds_lfht_node *node, *next; | |
1365 | unsigned long reverse_hash; | |
1366 | void *key; | |
1367 | size_t key_len; | |
1368 | ||
1369 | node = iter->node; | |
1370 | reverse_hash = node->p.reverse_hash; | |
1371 | key = node->key; | |
1372 | key_len = node->key_len; | |
1373 | next = iter->next; | |
1374 | node = clear_flag(next); | |
1375 | ||
1376 | for (;;) { | |
1377 | if (unlikely(is_end(node))) { | |
1378 | node = next = NULL; | |
1379 | break; | |
1380 | } | |
1381 | if (unlikely(node->p.reverse_hash > reverse_hash)) { | |
1382 | node = next = NULL; | |
1383 | break; | |
1384 | } | |
1385 | next = rcu_dereference(node->p.next); | |
1386 | if (likely(!is_removed(next)) | |
1387 | && !is_dummy(next) | |
1388 | && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) { | |
1389 | break; | |
1390 | } | |
1391 | node = clear_flag(next); | |
1392 | } | |
1393 | assert(!node || !is_dummy(rcu_dereference(node->p.next))); | |
1394 | iter->node = node; | |
1395 | iter->next = next; | |
1396 | } | |
1397 | ||
f6a9efaa DG |
1398 | void cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_iter *iter) |
1399 | { | |
1400 | struct cds_lfht_node *node, *next; | |
1401 | ||
1402 | node = clear_flag(iter->next); | |
1403 | for (;;) { | |
1404 | if (unlikely(is_end(node))) { | |
1405 | node = next = NULL; | |
1406 | break; | |
1407 | } | |
1408 | next = rcu_dereference(node->p.next); | |
1409 | if (likely(!is_removed(next)) | |
1410 | && !is_dummy(next)) { | |
1411 | break; | |
1412 | } | |
1413 | node = clear_flag(next); | |
1414 | } | |
1415 | assert(!node || !is_dummy(rcu_dereference(node->p.next))); | |
1416 | iter->node = node; | |
1417 | iter->next = next; | |
1418 | } | |
1419 | ||
1420 | void cds_lfht_first(struct cds_lfht *ht, struct cds_lfht_iter *iter) | |
1421 | { | |
1422 | struct _cds_lfht_node *lookup; | |
1423 | ||
1424 | /* | |
1425 | * Get next after first dummy node. The first dummy node is the | |
1426 | * first node of the linked list. | |
1427 | */ | |
1428 | lookup = &ht->t.tbl[0]->nodes[0]; | |
1429 | iter->next = lookup->next; | |
1430 | cds_lfht_next(ht, iter); | |
1431 | } | |
1432 | ||
fa68aa62 MD |
1433 | void cds_lfht_add(struct cds_lfht *ht, struct cds_lfht_node *node) |
1434 | { | |
1435 | unsigned long hash, size; | |
1436 | ||
1437 | hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed); | |
1438 | node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash); | |
1439 | ||
1440 | size = rcu_dereference(ht->t.size); | |
1441 | (void) _cds_lfht_add(ht, size, node, ADD_DEFAULT, 0); | |
1442 | ht_count_add(ht, size); | |
1443 | } | |
1444 | ||
1445 | struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, | |
1446 | struct cds_lfht_node *node) | |
1447 | { | |
1448 | unsigned long hash, size; | |
1449 | struct cds_lfht_node *ret; | |
1450 | ||
1451 | hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed); | |
1452 | node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash); | |
1453 | ||
1454 | size = rcu_dereference(ht->t.size); | |
1455 | ret = _cds_lfht_add(ht, size, node, ADD_UNIQUE, 0); | |
1456 | if (ret == node) | |
1457 | ht_count_add(ht, size); | |
1458 | return ret; | |
1459 | } | |
1460 | ||
1461 | struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht, | |
1462 | struct cds_lfht_node *node) | |
1463 | { | |
1464 | unsigned long hash, size; | |
1465 | struct cds_lfht_node *ret; | |
1466 | ||
1467 | hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed); | |
1468 | node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash); | |
1469 | ||
1470 | size = rcu_dereference(ht->t.size); | |
1471 | ret = _cds_lfht_add(ht, size, node, ADD_REPLACE, 0); | |
1472 | if (ret == NULL) | |
1473 | ht_count_add(ht, size); | |
1474 | return ret; | |
1475 | } | |
1476 | ||
1477 | int cds_lfht_replace(struct cds_lfht *ht, struct cds_lfht_iter *old_iter, | |
1478 | struct cds_lfht_node *new_node) | |
1479 | { | |
1480 | unsigned long size; | |
1481 | ||
1482 | size = rcu_dereference(ht->t.size); | |
1483 | return _cds_lfht_replace(ht, size, old_iter->node, old_iter->next, | |
1484 | new_node); | |
1485 | } | |
1486 | ||
1487 | int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_iter *iter) | |
1488 | { | |
1489 | unsigned long size; | |
1490 | int ret; | |
1491 | ||
1492 | size = rcu_dereference(ht->t.size); | |
1493 | ret = _cds_lfht_del(ht, size, iter->node, 0); | |
1494 | if (!ret) | |
1495 | ht_count_del(ht, size); | |
1496 | return ret; | |
1497 | } | |
1498 | ||
1499 | static | |
1500 | int cds_lfht_delete_dummy(struct cds_lfht *ht) | |
1501 | { | |
1502 | struct cds_lfht_node *node; | |
1503 | struct _cds_lfht_node *lookup; | |
1504 | unsigned long order, i, size; | |
1505 | ||
1506 | /* Check that the table is empty */ | |
1507 | lookup = &ht->t.tbl[0]->nodes[0]; | |
1508 | node = (struct cds_lfht_node *) lookup; | |
1509 | do { | |
1510 | node = clear_flag(node)->p.next; | |
1511 | if (!is_dummy(node)) | |
1512 | return -EPERM; | |
1513 | assert(!is_removed(node)); | |
1514 | } while (!is_end(node)); | |
1515 | /* | |
1516 | * size accessed without rcu_dereference because hash table is | |
1517 | * being destroyed. | |
1518 | */ | |
1519 | size = ht->t.size; | |
1520 | /* Internal sanity check: all nodes left should be dummy */ | |
1521 | for (order = 0; order < get_count_order_ulong(size) + 1; order++) { | |
1522 | unsigned long len; | |
1523 | ||
1524 | len = !order ? 1 : 1UL << (order - 1); | |
1525 | for (i = 0; i < len; i++) { | |
1526 | dbg_printf("delete order %lu i %lu hash %lu\n", | |
1527 | order, i, | |
1528 | bit_reverse_ulong(ht->t.tbl[order]->nodes[i].reverse_hash)); | |
1529 | assert(is_dummy(ht->t.tbl[order]->nodes[i].next)); | |
1530 | } | |
1531 | poison_free(ht->t.tbl[order]); | |
1532 | } | |
1533 | return 0; | |
1534 | } | |
1535 | ||
1536 | /* | |
1537 | * Should only be called when no more concurrent readers nor writers can | |
1538 | * possibly access the table. | |
1539 | */ | |
1540 | int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr) | |
1541 | { | |
1542 | int ret; | |
1543 | ||
1544 | /* Wait for in-flight resize operations to complete */ | |
1545 | CMM_STORE_SHARED(ht->in_progress_destroy, 1); | |
1546 | while (uatomic_read(&ht->in_progress_resize)) | |
1547 | poll(NULL, 0, 100); /* wait for 100ms */ | |
1548 | ret = cds_lfht_delete_dummy(ht); | |
1549 | if (ret) | |
1550 | return ret; | |
1551 | free_per_cpu_items_count(ht->percpu_count); | |
1552 | if (attr) | |
1553 | *attr = ht->resize_attr; | |
1554 | poison_free(ht); | |
1555 | return ret; | |
1556 | } | |
1557 | ||
1558 | void cds_lfht_count_nodes(struct cds_lfht *ht, | |
1559 | long *approx_before, | |
1560 | unsigned long *count, | |
1561 | unsigned long *removed, | |
1562 | long *approx_after) | |
1563 | { | |
1564 | struct cds_lfht_node *node, *next; | |
1565 | struct _cds_lfht_node *lookup; | |
1566 | unsigned long nr_dummy = 0; | |
1567 | ||
1568 | *approx_before = 0; | |
1569 | if (nr_cpus_mask >= 0) { | |
1570 | int i; | |
1571 | ||
1572 | for (i = 0; i < nr_cpus_mask + 1; i++) { | |
1573 | *approx_before += uatomic_read(&ht->percpu_count[i].add); | |
1574 | *approx_before -= uatomic_read(&ht->percpu_count[i].del); | |
1575 | } | |
1576 | } | |
1577 | ||
1578 | *count = 0; | |
1579 | *removed = 0; | |
1580 | ||
1581 | /* Count non-dummy nodes in the table */ | |
1582 | lookup = &ht->t.tbl[0]->nodes[0]; | |
1583 | node = (struct cds_lfht_node *) lookup; | |
1584 | do { | |
1585 | next = rcu_dereference(node->p.next); | |
1586 | if (is_removed(next)) { | |
1587 | if (!is_dummy(next)) | |
1588 | (*removed)++; | |
1589 | else | |
1590 | (nr_dummy)++; | |
1591 | } else if (!is_dummy(next)) | |
1592 | (*count)++; | |
1593 | else | |
1594 | (nr_dummy)++; | |
1595 | node = clear_flag(next); | |
1596 | } while (!is_end(node)); | |
1597 | dbg_printf("number of dummy nodes: %lu\n", nr_dummy); | |
1598 | *approx_after = 0; | |
1599 | if (nr_cpus_mask >= 0) { | |
1600 | int i; | |
1601 | ||
1602 | for (i = 0; i < nr_cpus_mask + 1; i++) { | |
1603 | *approx_after += uatomic_read(&ht->percpu_count[i].add); | |
1604 | *approx_after -= uatomic_read(&ht->percpu_count[i].del); | |
1605 | } | |
1606 | } | |
1607 | } | |
1608 | ||
1609 | /* called with resize mutex held */ | |
1610 | static | |
1611 | void _do_cds_lfht_grow(struct cds_lfht *ht, | |
1612 | unsigned long old_size, unsigned long new_size) | |
1613 | { | |
1614 | unsigned long old_order, new_order; | |
1615 | ||
1616 | old_order = get_count_order_ulong(old_size) + 1; | |
1617 | new_order = get_count_order_ulong(new_size) + 1; | |
1618 | printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", | |
1619 | old_size, old_order, new_size, new_order); | |
1620 | assert(new_size > old_size); | |
1621 | init_table(ht, old_order, new_order - old_order); | |
1622 | } | |
1623 | ||
1624 | /* called with resize mutex held */ | |
1625 | static | |
1626 | void _do_cds_lfht_shrink(struct cds_lfht *ht, | |
1627 | unsigned long old_size, unsigned long new_size) | |
1628 | { | |
1629 | unsigned long old_order, new_order; | |
1630 | ||
1631 | new_size = max(new_size, MIN_TABLE_SIZE); | |
1632 | old_order = get_count_order_ulong(old_size) + 1; | |
1633 | new_order = get_count_order_ulong(new_size) + 1; | |
1634 | printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", | |
1635 | old_size, old_order, new_size, new_order); | |
1636 | assert(new_size < old_size); | |
1637 | ||
1638 | /* Remove and unlink all dummy nodes to remove. */ | |
1639 | fini_table(ht, new_order, old_order - new_order); | |
1640 | } | |
1641 | ||
1642 | ||
1643 | /* called with resize mutex held */ | |
1644 | static | |
1645 | void _do_cds_lfht_resize(struct cds_lfht *ht) | |
1646 | { | |
1647 | unsigned long new_size, old_size; | |
1648 | ||
1649 | /* | |
1650 | * Resize table, re-do if the target size has changed under us. | |
1651 | */ | |
1652 | do { | |
1653 | ht->t.resize_initiated = 1; | |
1654 | old_size = ht->t.size; | |
1655 | new_size = CMM_LOAD_SHARED(ht->t.resize_target); | |
1656 | if (old_size < new_size) | |
1657 | _do_cds_lfht_grow(ht, old_size, new_size); | |
1658 | else if (old_size > new_size) | |
1659 | _do_cds_lfht_shrink(ht, old_size, new_size); | |
1660 | ht->t.resize_initiated = 0; | |
1661 | /* write resize_initiated before read resize_target */ | |
1662 | cmm_smp_mb(); | |
1663 | } while (ht->t.size != CMM_LOAD_SHARED(ht->t.resize_target)); | |
1664 | } | |
1665 | ||
1666 | static | |
1667 | unsigned long resize_target_update(struct cds_lfht *ht, unsigned long size, | |
1668 | int growth_order) | |
1669 | { | |
1670 | return _uatomic_max(&ht->t.resize_target, | |
1671 | size << growth_order); | |
1672 | } | |
1673 | ||
1674 | static | |
1675 | void resize_target_update_count(struct cds_lfht *ht, | |
1676 | unsigned long count) | |
1677 | { | |
1678 | count = max(count, MIN_TABLE_SIZE); | |
1679 | uatomic_set(&ht->t.resize_target, count); | |
1680 | } | |
1681 | ||
1682 | void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size) | |
1683 | { | |
1684 | resize_target_update_count(ht, new_size); | |
1685 | CMM_STORE_SHARED(ht->t.resize_initiated, 1); | |
1686 | ht->cds_lfht_rcu_thread_offline(); | |
1687 | pthread_mutex_lock(&ht->resize_mutex); | |
1688 | _do_cds_lfht_resize(ht); | |
1689 | pthread_mutex_unlock(&ht->resize_mutex); | |
1690 | ht->cds_lfht_rcu_thread_online(); | |
1691 | } | |
1692 | ||
1693 | static | |
1694 | void do_resize_cb(struct rcu_head *head) | |
1695 | { | |
1696 | struct rcu_resize_work *work = | |
1697 | caa_container_of(head, struct rcu_resize_work, head); | |
1698 | struct cds_lfht *ht = work->ht; | |
1699 | ||
1700 | ht->cds_lfht_rcu_thread_offline(); | |
1701 | pthread_mutex_lock(&ht->resize_mutex); | |
1702 | _do_cds_lfht_resize(ht); | |
1703 | pthread_mutex_unlock(&ht->resize_mutex); | |
1704 | ht->cds_lfht_rcu_thread_online(); | |
1705 | poison_free(work); | |
1706 | cmm_smp_mb(); /* finish resize before decrement */ | |
1707 | uatomic_dec(&ht->in_progress_resize); | |
1708 | } | |
1709 | ||
1710 | static | |
1711 | void cds_lfht_resize_lazy(struct cds_lfht *ht, unsigned long size, int growth) | |
1712 | { | |
1713 | struct rcu_resize_work *work; | |
1714 | unsigned long target_size; | |
1715 | ||
1716 | target_size = resize_target_update(ht, size, growth); | |
1717 | /* Store resize_target before read resize_initiated */ | |
1718 | cmm_smp_mb(); | |
1719 | if (!CMM_LOAD_SHARED(ht->t.resize_initiated) && size < target_size) { | |
1720 | uatomic_inc(&ht->in_progress_resize); | |
1721 | cmm_smp_mb(); /* increment resize count before calling it */ | |
1722 | work = malloc(sizeof(*work)); | |
1723 | work->ht = ht; | |
1724 | ht->cds_lfht_call_rcu(&work->head, do_resize_cb); | |
1725 | CMM_STORE_SHARED(ht->t.resize_initiated, 1); | |
1726 | } | |
1727 | } | |
1728 | ||
1729 | #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) | |
1730 | ||
1731 | static | |
1732 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, | |
1733 | unsigned long count) | |
1734 | { | |
1735 | struct rcu_resize_work *work; | |
1736 | ||
1737 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) | |
1738 | return; | |
1739 | resize_target_update_count(ht, count); | |
1740 | /* Store resize_target before read resize_initiated */ | |
1741 | cmm_smp_mb(); | |
1742 | if (!CMM_LOAD_SHARED(ht->t.resize_initiated)) { | |
1743 | uatomic_inc(&ht->in_progress_resize); | |
1744 | cmm_smp_mb(); /* increment resize count before calling it */ | |
1745 | work = malloc(sizeof(*work)); | |
1746 | work->ht = ht; | |
1747 | ht->cds_lfht_call_rcu(&work->head, do_resize_cb); | |
1748 | CMM_STORE_SHARED(ht->t.resize_initiated, 1); | |
1749 | } | |
1750 | } | |
1751 | ||
1752 | #endif |