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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 | ||
f8994aee MD |
122 | /* |
123 | * Per-CPU split-counters lazily update the global counter each 1024 | |
124 | * addition/removal. It automatically keeps track of resize required. | |
125 | * We use the bucket length as indicator for need to expand for small | |
126 | * tables and machines lacking per-cpu data suppport. | |
127 | */ | |
128 | #define COUNT_COMMIT_ORDER 10 | |
6ea6bc67 MD |
129 | #define CHAIN_LEN_TARGET 1 |
130 | #define CHAIN_LEN_RESIZE_THRESHOLD 3 | |
2ed95849 | 131 | |
abc490a1 MD |
132 | #ifndef max |
133 | #define max(a, b) ((a) > (b) ? (a) : (b)) | |
134 | #endif | |
2ed95849 | 135 | |
d95bd160 MD |
136 | /* |
137 | * The removed flag needs to be updated atomically with the pointer. | |
138 | * The dummy flag does not require to be updated atomically with the | |
139 | * pointer, but it is added as a pointer low bit flag to save space. | |
140 | */ | |
d37166c6 | 141 | #define REMOVED_FLAG (1UL << 0) |
f5596c94 MD |
142 | #define DUMMY_FLAG (1UL << 1) |
143 | #define FLAGS_MASK ((1UL << 2) - 1) | |
d37166c6 | 144 | |
df44348d | 145 | struct ht_items_count { |
3171717f | 146 | unsigned long add, remove; |
df44348d MD |
147 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
148 | ||
395270b6 | 149 | struct rcu_table { |
abc490a1 | 150 | unsigned long size; /* always a power of 2 */ |
f9830efd | 151 | unsigned long resize_target; |
11519af6 | 152 | int resize_initiated; |
abc490a1 | 153 | struct rcu_head head; |
14044b37 | 154 | struct _cds_lfht_node *tbl[0]; |
395270b6 MD |
155 | }; |
156 | ||
14044b37 | 157 | struct cds_lfht { |
395270b6 | 158 | struct rcu_table *t; /* shared */ |
14044b37 MD |
159 | cds_lfht_hash_fct hash_fct; |
160 | cds_lfht_compare_fct compare_fct; | |
732ad076 | 161 | unsigned long hash_seed; |
464a1ec9 | 162 | pthread_mutex_t resize_mutex; /* resize mutex: add/del mutex */ |
33c7c748 | 163 | unsigned int in_progress_resize, in_progress_destroy; |
14044b37 | 164 | void (*cds_lfht_call_rcu)(struct rcu_head *head, |
abc490a1 | 165 | void (*func)(struct rcu_head *head)); |
df44348d MD |
166 | unsigned long count; /* global approximate item count */ |
167 | struct ht_items_count *percpu_count; /* per-cpu item count */ | |
2ed95849 MD |
168 | }; |
169 | ||
abc490a1 MD |
170 | struct rcu_resize_work { |
171 | struct rcu_head head; | |
14044b37 | 172 | struct cds_lfht *ht; |
abc490a1 | 173 | }; |
2ed95849 | 174 | |
abc490a1 MD |
175 | /* |
176 | * Algorithm to reverse bits in a word by lookup table, extended to | |
177 | * 64-bit words. | |
f9830efd | 178 | * Source: |
abc490a1 | 179 | * http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable |
f9830efd | 180 | * Originally from Public Domain. |
abc490a1 MD |
181 | */ |
182 | ||
183 | static const uint8_t BitReverseTable256[256] = | |
2ed95849 | 184 | { |
abc490a1 MD |
185 | #define R2(n) (n), (n) + 2*64, (n) + 1*64, (n) + 3*64 |
186 | #define R4(n) R2(n), R2((n) + 2*16), R2((n) + 1*16), R2((n) + 3*16) | |
187 | #define R6(n) R4(n), R4((n) + 2*4 ), R4((n) + 1*4 ), R4((n) + 3*4 ) | |
188 | R6(0), R6(2), R6(1), R6(3) | |
189 | }; | |
190 | #undef R2 | |
191 | #undef R4 | |
192 | #undef R6 | |
2ed95849 | 193 | |
abc490a1 MD |
194 | static |
195 | uint8_t bit_reverse_u8(uint8_t v) | |
196 | { | |
197 | return BitReverseTable256[v]; | |
198 | } | |
ab7d5fc6 | 199 | |
abc490a1 MD |
200 | static __attribute__((unused)) |
201 | uint32_t bit_reverse_u32(uint32_t v) | |
202 | { | |
203 | return ((uint32_t) bit_reverse_u8(v) << 24) | | |
204 | ((uint32_t) bit_reverse_u8(v >> 8) << 16) | | |
205 | ((uint32_t) bit_reverse_u8(v >> 16) << 8) | | |
206 | ((uint32_t) bit_reverse_u8(v >> 24)); | |
2ed95849 MD |
207 | } |
208 | ||
abc490a1 MD |
209 | static __attribute__((unused)) |
210 | uint64_t bit_reverse_u64(uint64_t v) | |
2ed95849 | 211 | { |
abc490a1 MD |
212 | return ((uint64_t) bit_reverse_u8(v) << 56) | |
213 | ((uint64_t) bit_reverse_u8(v >> 8) << 48) | | |
214 | ((uint64_t) bit_reverse_u8(v >> 16) << 40) | | |
215 | ((uint64_t) bit_reverse_u8(v >> 24) << 32) | | |
216 | ((uint64_t) bit_reverse_u8(v >> 32) << 24) | | |
217 | ((uint64_t) bit_reverse_u8(v >> 40) << 16) | | |
218 | ((uint64_t) bit_reverse_u8(v >> 48) << 8) | | |
219 | ((uint64_t) bit_reverse_u8(v >> 56)); | |
220 | } | |
221 | ||
222 | static | |
223 | unsigned long bit_reverse_ulong(unsigned long v) | |
224 | { | |
225 | #if (CAA_BITS_PER_LONG == 32) | |
226 | return bit_reverse_u32(v); | |
227 | #else | |
228 | return bit_reverse_u64(v); | |
229 | #endif | |
230 | } | |
231 | ||
f9830efd | 232 | /* |
24365af7 MD |
233 | * fls: returns the position of the most significant bit. |
234 | * Returns 0 if no bit is set, else returns the position of the most | |
235 | * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit). | |
f9830efd | 236 | */ |
24365af7 MD |
237 | #if defined(__i386) || defined(__x86_64) |
238 | static inline | |
239 | unsigned int fls_u32(uint32_t x) | |
f9830efd | 240 | { |
24365af7 MD |
241 | int r; |
242 | ||
243 | asm("bsrl %1,%0\n\t" | |
244 | "jnz 1f\n\t" | |
245 | "movl $-1,%0\n\t" | |
246 | "1:\n\t" | |
247 | : "=r" (r) : "rm" (x)); | |
248 | return r + 1; | |
249 | } | |
250 | #define HAS_FLS_U32 | |
251 | #endif | |
252 | ||
253 | #if defined(__x86_64) | |
254 | static inline | |
255 | unsigned int fls_u64(uint64_t x) | |
256 | { | |
257 | long r; | |
258 | ||
259 | asm("bsrq %1,%0\n\t" | |
260 | "jnz 1f\n\t" | |
261 | "movq $-1,%0\n\t" | |
262 | "1:\n\t" | |
263 | : "=r" (r) : "rm" (x)); | |
264 | return r + 1; | |
265 | } | |
266 | #define HAS_FLS_U64 | |
267 | #endif | |
268 | ||
269 | #ifndef HAS_FLS_U64 | |
270 | static __attribute__((unused)) | |
271 | unsigned int fls_u64(uint64_t x) | |
272 | { | |
273 | unsigned int r = 64; | |
274 | ||
275 | if (!x) | |
276 | return 0; | |
277 | ||
278 | if (!(x & 0xFFFFFFFF00000000ULL)) { | |
279 | x <<= 32; | |
280 | r -= 32; | |
281 | } | |
282 | if (!(x & 0xFFFF000000000000ULL)) { | |
283 | x <<= 16; | |
284 | r -= 16; | |
285 | } | |
286 | if (!(x & 0xFF00000000000000ULL)) { | |
287 | x <<= 8; | |
288 | r -= 8; | |
289 | } | |
290 | if (!(x & 0xF000000000000000ULL)) { | |
291 | x <<= 4; | |
292 | r -= 4; | |
293 | } | |
294 | if (!(x & 0xC000000000000000ULL)) { | |
295 | x <<= 2; | |
296 | r -= 2; | |
297 | } | |
298 | if (!(x & 0x8000000000000000ULL)) { | |
299 | x <<= 1; | |
300 | r -= 1; | |
301 | } | |
302 | return r; | |
303 | } | |
304 | #endif | |
305 | ||
306 | #ifndef HAS_FLS_U32 | |
307 | static __attribute__((unused)) | |
308 | unsigned int fls_u32(uint32_t x) | |
309 | { | |
310 | unsigned int r = 32; | |
f9830efd | 311 | |
24365af7 MD |
312 | if (!x) |
313 | return 0; | |
314 | if (!(x & 0xFFFF0000U)) { | |
315 | x <<= 16; | |
316 | r -= 16; | |
317 | } | |
318 | if (!(x & 0xFF000000U)) { | |
319 | x <<= 8; | |
320 | r -= 8; | |
321 | } | |
322 | if (!(x & 0xF0000000U)) { | |
323 | x <<= 4; | |
324 | r -= 4; | |
325 | } | |
326 | if (!(x & 0xC0000000U)) { | |
327 | x <<= 2; | |
328 | r -= 2; | |
329 | } | |
330 | if (!(x & 0x80000000U)) { | |
331 | x <<= 1; | |
332 | r -= 1; | |
333 | } | |
334 | return r; | |
335 | } | |
336 | #endif | |
337 | ||
338 | unsigned int fls_ulong(unsigned long x) | |
f9830efd | 339 | { |
24365af7 MD |
340 | #if (CAA_BITS_PER_lONG == 32) |
341 | return fls_u32(x); | |
342 | #else | |
343 | return fls_u64(x); | |
344 | #endif | |
345 | } | |
f9830efd | 346 | |
24365af7 MD |
347 | int get_count_order_u32(uint32_t x) |
348 | { | |
349 | int order; | |
350 | ||
351 | order = fls_u32(x) - 1; | |
352 | if (x & (x - 1)) | |
353 | order++; | |
354 | return order; | |
355 | } | |
356 | ||
357 | int get_count_order_ulong(unsigned long x) | |
358 | { | |
359 | int order; | |
360 | ||
361 | order = fls_ulong(x) - 1; | |
362 | if (x & (x - 1)) | |
363 | order++; | |
364 | return order; | |
f9830efd MD |
365 | } |
366 | ||
367 | static | |
14044b37 | 368 | void cds_lfht_resize_lazy(struct cds_lfht *ht, struct rcu_table *t, int growth); |
f9830efd | 369 | |
df44348d MD |
370 | /* |
371 | * If the sched_getcpu() and sysconf(_SC_NPROCESSORS_CONF) calls are | |
372 | * available, then we support hash table item accounting. | |
373 | * In the unfortunate event the number of CPUs reported would be | |
374 | * inaccurate, we use modulo arithmetic on the number of CPUs we got. | |
375 | */ | |
df44348d MD |
376 | #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) |
377 | ||
f8994aee MD |
378 | static |
379 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, struct rcu_table *t, | |
380 | unsigned long count); | |
381 | ||
df44348d MD |
382 | static long nr_cpus_mask = -1; |
383 | ||
384 | static | |
385 | struct ht_items_count *alloc_per_cpu_items_count(void) | |
386 | { | |
387 | struct ht_items_count *count; | |
388 | ||
389 | switch (nr_cpus_mask) { | |
390 | case -2: | |
391 | return NULL; | |
392 | case -1: | |
393 | { | |
394 | long maxcpus; | |
395 | ||
396 | maxcpus = sysconf(_SC_NPROCESSORS_CONF); | |
397 | if (maxcpus <= 0) { | |
398 | nr_cpus_mask = -2; | |
399 | return NULL; | |
400 | } | |
401 | /* | |
402 | * round up number of CPUs to next power of two, so we | |
403 | * can use & for modulo. | |
404 | */ | |
405 | maxcpus = 1UL << get_count_order_ulong(maxcpus); | |
406 | nr_cpus_mask = maxcpus - 1; | |
407 | } | |
408 | /* Fall-through */ | |
409 | default: | |
410 | return calloc(nr_cpus_mask + 1, sizeof(*count)); | |
411 | } | |
412 | } | |
413 | ||
414 | static | |
415 | void free_per_cpu_items_count(struct ht_items_count *count) | |
416 | { | |
417 | free(count); | |
418 | } | |
419 | ||
420 | static | |
421 | int ht_get_cpu(void) | |
422 | { | |
423 | int cpu; | |
424 | ||
425 | assert(nr_cpus_mask >= 0); | |
426 | cpu = sched_getcpu(); | |
427 | if (unlikely(cpu < 0)) | |
428 | return cpu; | |
429 | else | |
430 | return cpu & nr_cpus_mask; | |
431 | } | |
432 | ||
433 | static | |
3171717f | 434 | void ht_count_add(struct cds_lfht *ht, struct rcu_table *t) |
df44348d | 435 | { |
3171717f | 436 | unsigned long percpu_count; |
df44348d MD |
437 | int cpu; |
438 | ||
439 | if (unlikely(!ht->percpu_count)) | |
3171717f | 440 | return; |
df44348d MD |
441 | cpu = ht_get_cpu(); |
442 | if (unlikely(cpu < 0)) | |
3171717f MD |
443 | return; |
444 | percpu_count = uatomic_add_return(&ht->percpu_count[cpu].add, 1); | |
df44348d MD |
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))) { | |
f8994aee MD |
453 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) |
454 | < t->size) | |
455 | return; | |
456 | dbg_printf("add set global %lu\n", count); | |
457 | cds_lfht_resize_lazy_count(ht, t, | |
6ea6bc67 | 458 | count >> (CHAIN_LEN_TARGET - 1)); |
df44348d MD |
459 | } |
460 | } | |
461 | } | |
462 | ||
463 | static | |
464 | void ht_count_remove(struct cds_lfht *ht, struct rcu_table *t) | |
465 | { | |
466 | unsigned long percpu_count; | |
3171717f | 467 | int cpu; |
df44348d | 468 | |
3171717f MD |
469 | if (unlikely(!ht->percpu_count)) |
470 | return; | |
471 | cpu = ht_get_cpu(); | |
472 | if (unlikely(cpu < 0)) | |
473 | return; | |
474 | percpu_count = uatomic_add_return(&ht->percpu_count[cpu].remove, -1); | |
df44348d MD |
475 | if (unlikely(!(percpu_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) { |
476 | unsigned long count; | |
477 | ||
478 | dbg_printf("remove percpu %lu\n", percpu_count); | |
479 | count = uatomic_add_return(&ht->count, | |
3171717f | 480 | -(1UL << COUNT_COMMIT_ORDER)); |
df44348d MD |
481 | /* If power of 2 */ |
482 | if (!(count & (count - 1))) { | |
f8994aee MD |
483 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) |
484 | >= t->size) | |
485 | return; | |
486 | dbg_printf("remove set global %lu\n", count); | |
487 | cds_lfht_resize_lazy_count(ht, t, | |
6ea6bc67 | 488 | count >> (CHAIN_LEN_TARGET - 1)); |
df44348d MD |
489 | } |
490 | } | |
491 | } | |
492 | ||
493 | #else /* #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */ | |
494 | ||
495 | static const long nr_cpus_mask = -1; | |
496 | ||
497 | static | |
498 | struct ht_items_count *alloc_per_cpu_items_count(void) | |
499 | { | |
500 | return NULL; | |
501 | } | |
502 | ||
503 | static | |
504 | void free_per_cpu_items_count(struct ht_items_count *count) | |
505 | { | |
506 | } | |
507 | ||
508 | static | |
f8994aee | 509 | void ht_count_add(struct cds_lfht *ht, struct rcu_table *t) |
df44348d MD |
510 | { |
511 | } | |
512 | ||
513 | static | |
f8994aee | 514 | void ht_count_remove(struct cds_lfht *ht, struct rcu_table *t) |
df44348d MD |
515 | { |
516 | } | |
517 | ||
518 | #endif /* #else #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */ | |
519 | ||
520 | ||
f9830efd | 521 | static |
14044b37 | 522 | void check_resize(struct cds_lfht *ht, struct rcu_table *t, |
f9830efd MD |
523 | uint32_t chain_len) |
524 | { | |
f8994aee MD |
525 | unsigned long count; |
526 | ||
527 | count = uatomic_read(&ht->count); | |
528 | /* | |
529 | * Use bucket-local length for small table expand and for | |
530 | * environments lacking per-cpu data support. | |
531 | */ | |
532 | if (count >= (1UL << COUNT_COMMIT_ORDER)) | |
533 | return; | |
24365af7 | 534 | if (chain_len > 100) |
f0c29ed7 | 535 | dbg_printf("WARNING: large chain length: %u.\n", |
24365af7 | 536 | chain_len); |
3390d470 | 537 | if (chain_len >= CHAIN_LEN_RESIZE_THRESHOLD) |
14044b37 | 538 | cds_lfht_resize_lazy(ht, t, |
01370f0b | 539 | get_count_order_u32(chain_len - (CHAIN_LEN_TARGET - 1))); |
f9830efd MD |
540 | } |
541 | ||
abc490a1 | 542 | static |
14044b37 | 543 | struct cds_lfht_node *clear_flag(struct cds_lfht_node *node) |
abc490a1 | 544 | { |
14044b37 | 545 | return (struct cds_lfht_node *) (((unsigned long) node) & ~FLAGS_MASK); |
abc490a1 MD |
546 | } |
547 | ||
548 | static | |
14044b37 | 549 | int is_removed(struct cds_lfht_node *node) |
abc490a1 | 550 | { |
d37166c6 | 551 | return ((unsigned long) node) & REMOVED_FLAG; |
abc490a1 MD |
552 | } |
553 | ||
554 | static | |
14044b37 | 555 | struct cds_lfht_node *flag_removed(struct cds_lfht_node *node) |
abc490a1 | 556 | { |
14044b37 | 557 | return (struct cds_lfht_node *) (((unsigned long) node) | REMOVED_FLAG); |
abc490a1 MD |
558 | } |
559 | ||
f5596c94 | 560 | static |
14044b37 | 561 | int is_dummy(struct cds_lfht_node *node) |
f5596c94 MD |
562 | { |
563 | return ((unsigned long) node) & DUMMY_FLAG; | |
564 | } | |
565 | ||
566 | static | |
14044b37 | 567 | struct cds_lfht_node *flag_dummy(struct cds_lfht_node *node) |
f5596c94 | 568 | { |
14044b37 | 569 | return (struct cds_lfht_node *) (((unsigned long) node) | DUMMY_FLAG); |
f5596c94 MD |
570 | } |
571 | ||
abc490a1 | 572 | static |
f9830efd | 573 | unsigned long _uatomic_max(unsigned long *ptr, unsigned long v) |
abc490a1 MD |
574 | { |
575 | unsigned long old1, old2; | |
576 | ||
577 | old1 = uatomic_read(ptr); | |
578 | do { | |
579 | old2 = old1; | |
580 | if (old2 >= v) | |
f9830efd | 581 | return old2; |
abc490a1 | 582 | } while ((old1 = uatomic_cmpxchg(ptr, old2, v)) != old2); |
f9830efd | 583 | return v; |
abc490a1 MD |
584 | } |
585 | ||
273399de MD |
586 | /* |
587 | * Remove all logically deleted nodes from a bucket up to a certain node key. | |
588 | */ | |
589 | static | |
14044b37 | 590 | void _cds_lfht_gc_bucket(struct cds_lfht_node *dummy, struct cds_lfht_node *node) |
273399de | 591 | { |
14044b37 | 592 | struct cds_lfht_node *iter_prev, *iter, *next, *new_next; |
273399de MD |
593 | |
594 | for (;;) { | |
595 | iter_prev = dummy; | |
596 | /* We can always skip the dummy node initially */ | |
cc4fcb10 MD |
597 | iter = rcu_dereference(iter_prev->p.next); |
598 | assert(iter_prev->p.reverse_hash <= node->p.reverse_hash); | |
273399de | 599 | for (;;) { |
a2974903 | 600 | if (unlikely(!clear_flag(iter))) |
479c8a32 | 601 | return; |
76412f24 | 602 | if (likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash)) |
273399de | 603 | return; |
cc4fcb10 | 604 | next = rcu_dereference(clear_flag(iter)->p.next); |
76412f24 | 605 | if (likely(is_removed(next))) |
273399de | 606 | break; |
b453eae1 | 607 | iter_prev = clear_flag(iter); |
273399de MD |
608 | iter = next; |
609 | } | |
610 | assert(!is_removed(iter)); | |
f5596c94 MD |
611 | if (is_dummy(iter)) |
612 | new_next = flag_dummy(clear_flag(next)); | |
613 | else | |
614 | new_next = clear_flag(next); | |
615 | (void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next); | |
273399de MD |
616 | } |
617 | } | |
618 | ||
abc490a1 | 619 | static |
14044b37 MD |
620 | struct cds_lfht_node *_cds_lfht_add(struct cds_lfht *ht, struct rcu_table *t, |
621 | struct cds_lfht_node *node, int unique, int dummy) | |
abc490a1 | 622 | { |
14044b37 | 623 | struct cds_lfht_node *iter_prev, *iter, *next, *new_node, *new_next, |
f5596c94 | 624 | *dummy_node; |
14044b37 | 625 | struct _cds_lfht_node *lookup; |
24365af7 | 626 | unsigned long hash, index, order; |
abc490a1 | 627 | |
18117871 | 628 | if (!t->size) { |
f5596c94 MD |
629 | assert(dummy); |
630 | node->p.next = flag_dummy(NULL); | |
18117871 MD |
631 | return node; /* Initial first add (head) */ |
632 | } | |
cc4fcb10 | 633 | hash = bit_reverse_ulong(node->p.reverse_hash); |
abc490a1 | 634 | for (;;) { |
f9830efd | 635 | uint32_t chain_len = 0; |
abc490a1 | 636 | |
11519af6 MD |
637 | /* |
638 | * iter_prev points to the non-removed node prior to the | |
639 | * insert location. | |
11519af6 | 640 | */ |
24365af7 MD |
641 | index = hash & (t->size - 1); |
642 | order = get_count_order_ulong(index + 1); | |
643 | lookup = &t->tbl[order][index & ((1UL << (order - 1)) - 1)]; | |
14044b37 | 644 | iter_prev = (struct cds_lfht_node *) lookup; |
11519af6 | 645 | /* We can always skip the dummy node initially */ |
cc4fcb10 MD |
646 | iter = rcu_dereference(iter_prev->p.next); |
647 | assert(iter_prev->p.reverse_hash <= node->p.reverse_hash); | |
abc490a1 | 648 | for (;;) { |
a2974903 | 649 | if (unlikely(!clear_flag(iter))) |
273399de | 650 | goto insert; |
76412f24 | 651 | if (likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash)) |
273399de | 652 | goto insert; |
cc4fcb10 | 653 | next = rcu_dereference(clear_flag(iter)->p.next); |
76412f24 | 654 | if (unlikely(is_removed(next))) |
9dba85be | 655 | goto gc_node; |
e43f23f8 | 656 | if (unique |
1b81fe1a | 657 | && !is_dummy(next) |
e43f23f8 MD |
658 | && !ht->compare_fct(node->key, node->key_len, |
659 | clear_flag(iter)->key, | |
660 | clear_flag(iter)->key_len)) | |
18117871 | 661 | return clear_flag(iter); |
11519af6 | 662 | /* Only account for identical reverse hash once */ |
24365af7 MD |
663 | if (iter_prev->p.reverse_hash != clear_flag(iter)->p.reverse_hash |
664 | && !is_dummy(next)) | |
11519af6 MD |
665 | check_resize(ht, t, ++chain_len); |
666 | iter_prev = clear_flag(iter); | |
273399de | 667 | iter = next; |
abc490a1 | 668 | } |
273399de | 669 | insert: |
7ec59d3b | 670 | assert(node != clear_flag(iter)); |
11519af6 | 671 | assert(!is_removed(iter_prev)); |
f000907d | 672 | assert(iter_prev != node); |
f5596c94 | 673 | if (!dummy) |
1b81fe1a | 674 | node->p.next = clear_flag(iter); |
f5596c94 | 675 | else |
1b81fe1a | 676 | node->p.next = flag_dummy(clear_flag(iter)); |
f5596c94 MD |
677 | if (is_dummy(iter)) |
678 | new_node = flag_dummy(node); | |
679 | else | |
680 | new_node = node; | |
cc4fcb10 | 681 | if (uatomic_cmpxchg(&iter_prev->p.next, iter, |
f5596c94 | 682 | new_node) != iter) |
273399de | 683 | continue; /* retry */ |
11519af6 | 684 | else |
273399de | 685 | goto gc_end; |
9dba85be MD |
686 | gc_node: |
687 | assert(!is_removed(iter)); | |
f5596c94 MD |
688 | if (is_dummy(iter)) |
689 | new_next = flag_dummy(clear_flag(next)); | |
690 | else | |
691 | new_next = clear_flag(next); | |
692 | (void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next); | |
273399de | 693 | /* retry */ |
464a1ec9 | 694 | } |
273399de MD |
695 | gc_end: |
696 | /* Garbage collect logically removed nodes in the bucket */ | |
24365af7 MD |
697 | index = hash & (t->size - 1); |
698 | order = get_count_order_ulong(index + 1); | |
699 | lookup = &t->tbl[order][index & ((1UL << (order - 1)) - 1)]; | |
14044b37 MD |
700 | dummy_node = (struct cds_lfht_node *) lookup; |
701 | _cds_lfht_gc_bucket(dummy_node, node); | |
18117871 | 702 | return node; |
abc490a1 | 703 | } |
464a1ec9 | 704 | |
abc490a1 | 705 | static |
14044b37 MD |
706 | int _cds_lfht_remove(struct cds_lfht *ht, struct rcu_table *t, |
707 | struct cds_lfht_node *node) | |
abc490a1 | 708 | { |
14044b37 MD |
709 | struct cds_lfht_node *dummy, *next, *old; |
710 | struct _cds_lfht_node *lookup; | |
abc490a1 | 711 | int flagged = 0; |
24365af7 | 712 | unsigned long hash, index, order; |
5e28c532 | 713 | |
7ec59d3b | 714 | /* logically delete the node */ |
cc4fcb10 | 715 | old = rcu_dereference(node->p.next); |
7ec59d3b MD |
716 | do { |
717 | next = old; | |
76412f24 | 718 | if (unlikely(is_removed(next))) |
7ec59d3b | 719 | goto end; |
1b81fe1a | 720 | assert(!is_dummy(next)); |
cc4fcb10 | 721 | old = uatomic_cmpxchg(&node->p.next, next, |
7ec59d3b MD |
722 | flag_removed(next)); |
723 | } while (old != next); | |
724 | ||
725 | /* We performed the (logical) deletion. */ | |
726 | flagged = 1; | |
727 | ||
728 | /* | |
729 | * Ensure that the node is not visible to readers anymore: lookup for | |
273399de MD |
730 | * the node, and remove it (along with any other logically removed node) |
731 | * if found. | |
11519af6 | 732 | */ |
cc4fcb10 | 733 | hash = bit_reverse_ulong(node->p.reverse_hash); |
24365af7 MD |
734 | index = hash & (t->size - 1); |
735 | order = get_count_order_ulong(index + 1); | |
736 | lookup = &t->tbl[order][index & ((1UL << (order - 1)) - 1)]; | |
14044b37 MD |
737 | dummy = (struct cds_lfht_node *) lookup; |
738 | _cds_lfht_gc_bucket(dummy, node); | |
2ed95849 | 739 | end: |
11519af6 MD |
740 | /* |
741 | * Only the flagging action indicated that we (and no other) | |
742 | * removed the node from the hash. | |
743 | */ | |
7ec59d3b | 744 | if (flagged) { |
cc4fcb10 | 745 | assert(is_removed(rcu_dereference(node->p.next))); |
11519af6 | 746 | return 0; |
7ec59d3b | 747 | } else |
11519af6 | 748 | return -ENOENT; |
abc490a1 | 749 | } |
2ed95849 | 750 | |
abc490a1 | 751 | static |
14044b37 | 752 | void init_table(struct cds_lfht *ht, struct rcu_table *t, |
24365af7 MD |
753 | unsigned long first_order, unsigned long len_order) |
754 | { | |
755 | unsigned long i, end_order; | |
756 | ||
f0c29ed7 | 757 | dbg_printf("init table: first_order %lu end_order %lu\n", |
24365af7 MD |
758 | first_order, first_order + len_order); |
759 | end_order = first_order + len_order; | |
760 | t->size = !first_order ? 0 : (1UL << (first_order - 1)); | |
761 | for (i = first_order; i < end_order; i++) { | |
762 | unsigned long j, len; | |
763 | ||
764 | len = !i ? 1 : 1UL << (i - 1); | |
f0c29ed7 | 765 | dbg_printf("init order %lu len: %lu\n", i, len); |
14044b37 | 766 | t->tbl[i] = calloc(len, sizeof(struct _cds_lfht_node)); |
24365af7 | 767 | for (j = 0; j < len; j++) { |
f0c29ed7 | 768 | dbg_printf("init entry: i %lu j %lu hash %lu\n", |
24365af7 | 769 | i, j, !i ? 0 : (1UL << (i - 1)) + j); |
14044b37 MD |
770 | struct cds_lfht_node *new_node = |
771 | (struct cds_lfht_node *) &t->tbl[i][j]; | |
24365af7 MD |
772 | new_node->p.reverse_hash = |
773 | bit_reverse_ulong(!i ? 0 : (1UL << (i - 1)) + j); | |
14044b37 | 774 | (void) _cds_lfht_add(ht, t, new_node, 0, 1); |
33c7c748 MD |
775 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
776 | break; | |
24365af7 MD |
777 | } |
778 | /* Update table size */ | |
779 | t->size = !i ? 1 : (1UL << i); | |
f0c29ed7 | 780 | dbg_printf("init new size: %lu\n", t->size); |
33c7c748 MD |
781 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
782 | break; | |
abc490a1 | 783 | } |
24365af7 | 784 | t->resize_target = t->size; |
11519af6 | 785 | t->resize_initiated = 0; |
2ed95849 MD |
786 | } |
787 | ||
14044b37 MD |
788 | struct cds_lfht *cds_lfht_new(cds_lfht_hash_fct hash_fct, |
789 | cds_lfht_compare_fct compare_fct, | |
790 | unsigned long hash_seed, | |
791 | unsigned long init_size, | |
792 | void (*cds_lfht_call_rcu)(struct rcu_head *head, | |
793 | void (*func)(struct rcu_head *head))) | |
abc490a1 | 794 | { |
14044b37 | 795 | struct cds_lfht *ht; |
24365af7 | 796 | unsigned long order; |
abc490a1 | 797 | |
8129be4e | 798 | /* init_size must be power of two */ |
49619ea0 | 799 | if (init_size && (init_size & (init_size - 1))) |
8129be4e | 800 | return NULL; |
14044b37 | 801 | ht = calloc(1, sizeof(struct cds_lfht)); |
abc490a1 | 802 | ht->hash_fct = hash_fct; |
732ad076 MD |
803 | ht->compare_fct = compare_fct; |
804 | ht->hash_seed = hash_seed; | |
14044b37 | 805 | ht->cds_lfht_call_rcu = cds_lfht_call_rcu; |
848d4088 | 806 | ht->in_progress_resize = 0; |
df44348d | 807 | ht->percpu_count = alloc_per_cpu_items_count(); |
abc490a1 MD |
808 | /* this mutex should not nest in read-side C.S. */ |
809 | pthread_mutex_init(&ht->resize_mutex, NULL); | |
24365af7 | 810 | order = get_count_order_ulong(max(init_size, 1)) + 1; |
14044b37 MD |
811 | ht->t = calloc(1, sizeof(struct cds_lfht) |
812 | + (order * sizeof(struct _cds_lfht_node *))); | |
abc490a1 | 813 | ht->t->size = 0; |
f000907d | 814 | pthread_mutex_lock(&ht->resize_mutex); |
24365af7 | 815 | init_table(ht, ht->t, 0, order); |
f000907d | 816 | pthread_mutex_unlock(&ht->resize_mutex); |
abc490a1 MD |
817 | return ht; |
818 | } | |
819 | ||
14044b37 | 820 | struct cds_lfht_node *cds_lfht_lookup(struct cds_lfht *ht, void *key, size_t key_len) |
2ed95849 | 821 | { |
395270b6 | 822 | struct rcu_table *t; |
14044b37 MD |
823 | struct cds_lfht_node *node, *next; |
824 | struct _cds_lfht_node *lookup; | |
24365af7 | 825 | unsigned long hash, reverse_hash, index, order; |
2ed95849 | 826 | |
732ad076 | 827 | hash = ht->hash_fct(key, key_len, ht->hash_seed); |
abc490a1 | 828 | reverse_hash = bit_reverse_ulong(hash); |
464a1ec9 | 829 | |
395270b6 | 830 | t = rcu_dereference(ht->t); |
24365af7 MD |
831 | index = hash & (t->size - 1); |
832 | order = get_count_order_ulong(index + 1); | |
833 | lookup = &t->tbl[order][index & ((1UL << (order - 1)) - 1)]; | |
f0c29ed7 | 834 | dbg_printf("lookup hash %lu index %lu order %lu aridx %lu\n", |
24365af7 | 835 | hash, index, order, index & ((1UL << (order - 1)) - 1)); |
14044b37 | 836 | node = (struct cds_lfht_node *) lookup; |
2ed95849 | 837 | for (;;) { |
abc490a1 MD |
838 | if (unlikely(!node)) |
839 | break; | |
cc4fcb10 | 840 | if (unlikely(node->p.reverse_hash > reverse_hash)) { |
abc490a1 MD |
841 | node = NULL; |
842 | break; | |
2ed95849 | 843 | } |
1b81fe1a MD |
844 | next = rcu_dereference(node->p.next); |
845 | if (likely(!is_removed(next)) | |
846 | && !is_dummy(next) | |
49c2e2d6 | 847 | && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) { |
273399de | 848 | break; |
2ed95849 | 849 | } |
1b81fe1a | 850 | node = clear_flag(next); |
2ed95849 | 851 | } |
1b81fe1a | 852 | assert(!node || !is_dummy(rcu_dereference(node->p.next))); |
abc490a1 MD |
853 | return node; |
854 | } | |
e0ba718a | 855 | |
a481e5ff MD |
856 | struct cds_lfht_node *cds_lfht_next(struct cds_lfht *ht, |
857 | struct cds_lfht_node *node) | |
858 | { | |
859 | struct cds_lfht_node *next; | |
860 | unsigned long reverse_hash; | |
861 | void *key; | |
862 | size_t key_len; | |
863 | ||
864 | reverse_hash = node->p.reverse_hash; | |
865 | key = node->key; | |
866 | key_len = node->key_len; | |
867 | next = rcu_dereference(node->p.next); | |
868 | node = clear_flag(next); | |
869 | ||
870 | for (;;) { | |
871 | if (unlikely(!node)) | |
872 | break; | |
873 | if (unlikely(node->p.reverse_hash > reverse_hash)) { | |
874 | node = NULL; | |
875 | break; | |
876 | } | |
877 | next = rcu_dereference(node->p.next); | |
878 | if (likely(!is_removed(next)) | |
879 | && !is_dummy(next) | |
880 | && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) { | |
881 | break; | |
882 | } | |
883 | node = clear_flag(next); | |
884 | } | |
885 | assert(!node || !is_dummy(rcu_dereference(node->p.next))); | |
886 | return node; | |
887 | } | |
888 | ||
14044b37 | 889 | void cds_lfht_add(struct cds_lfht *ht, struct cds_lfht_node *node) |
abc490a1 MD |
890 | { |
891 | struct rcu_table *t; | |
49c2e2d6 | 892 | unsigned long hash; |
ab7d5fc6 | 893 | |
49c2e2d6 | 894 | hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed); |
cc4fcb10 | 895 | node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash); |
2ed95849 | 896 | |
abc490a1 | 897 | t = rcu_dereference(ht->t); |
14044b37 | 898 | (void) _cds_lfht_add(ht, t, node, 0, 0); |
df44348d | 899 | ht_count_add(ht, t); |
3eca1b8c MD |
900 | } |
901 | ||
14044b37 MD |
902 | struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, |
903 | struct cds_lfht_node *node) | |
3eca1b8c MD |
904 | { |
905 | struct rcu_table *t; | |
49c2e2d6 | 906 | unsigned long hash; |
df44348d | 907 | struct cds_lfht_node *ret; |
3eca1b8c | 908 | |
49c2e2d6 | 909 | hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed); |
cc4fcb10 | 910 | node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash); |
3eca1b8c MD |
911 | |
912 | t = rcu_dereference(ht->t); | |
df44348d MD |
913 | ret = _cds_lfht_add(ht, t, node, 1, 0); |
914 | if (ret != node) | |
915 | ht_count_add(ht, t); | |
916 | return ret; | |
2ed95849 MD |
917 | } |
918 | ||
14044b37 | 919 | int cds_lfht_remove(struct cds_lfht *ht, struct cds_lfht_node *node) |
2ed95849 | 920 | { |
abc490a1 | 921 | struct rcu_table *t; |
df44348d | 922 | int ret; |
abc490a1 MD |
923 | |
924 | t = rcu_dereference(ht->t); | |
df44348d MD |
925 | ret = _cds_lfht_remove(ht, t, node); |
926 | if (!ret) | |
927 | ht_count_remove(ht, t); | |
928 | return ret; | |
2ed95849 | 929 | } |
ab7d5fc6 | 930 | |
abc490a1 | 931 | static |
14044b37 | 932 | int cds_lfht_delete_dummy(struct cds_lfht *ht) |
674f7a69 | 933 | { |
395270b6 | 934 | struct rcu_table *t; |
14044b37 MD |
935 | struct cds_lfht_node *node; |
936 | struct _cds_lfht_node *lookup; | |
24365af7 | 937 | unsigned long order, i; |
674f7a69 | 938 | |
abc490a1 MD |
939 | t = ht->t; |
940 | /* Check that the table is empty */ | |
24365af7 | 941 | lookup = &t->tbl[0][0]; |
14044b37 | 942 | node = (struct cds_lfht_node *) lookup; |
abc490a1 | 943 | do { |
1b81fe1a MD |
944 | node = clear_flag(node)->p.next; |
945 | if (!is_dummy(node)) | |
abc490a1 | 946 | return -EPERM; |
273399de | 947 | assert(!is_removed(node)); |
a2974903 | 948 | } while (clear_flag(node)); |
abc490a1 | 949 | /* Internal sanity check: all nodes left should be dummy */ |
24365af7 MD |
950 | for (order = 0; order < get_count_order_ulong(t->size) + 1; order++) { |
951 | unsigned long len; | |
952 | ||
953 | len = !order ? 1 : 1UL << (order - 1); | |
954 | for (i = 0; i < len; i++) { | |
f0c29ed7 | 955 | dbg_printf("delete order %lu i %lu hash %lu\n", |
24365af7 MD |
956 | order, i, |
957 | bit_reverse_ulong(t->tbl[order][i].reverse_hash)); | |
958 | assert(is_dummy(t->tbl[order][i].next)); | |
959 | } | |
960 | free(t->tbl[order]); | |
674f7a69 | 961 | } |
abc490a1 | 962 | return 0; |
674f7a69 MD |
963 | } |
964 | ||
965 | /* | |
966 | * Should only be called when no more concurrent readers nor writers can | |
967 | * possibly access the table. | |
968 | */ | |
14044b37 | 969 | int cds_lfht_destroy(struct cds_lfht *ht) |
674f7a69 | 970 | { |
5e28c532 MD |
971 | int ret; |
972 | ||
848d4088 | 973 | /* Wait for in-flight resize operations to complete */ |
33c7c748 | 974 | CMM_STORE_SHARED(ht->in_progress_destroy, 1); |
848d4088 MD |
975 | while (uatomic_read(&ht->in_progress_resize)) |
976 | poll(NULL, 0, 100); /* wait for 100ms */ | |
14044b37 | 977 | ret = cds_lfht_delete_dummy(ht); |
abc490a1 MD |
978 | if (ret) |
979 | return ret; | |
395270b6 | 980 | free(ht->t); |
df44348d | 981 | free_per_cpu_items_count(ht->percpu_count); |
674f7a69 | 982 | free(ht); |
5e28c532 | 983 | return ret; |
674f7a69 MD |
984 | } |
985 | ||
14044b37 | 986 | void cds_lfht_count_nodes(struct cds_lfht *ht, |
273399de MD |
987 | unsigned long *count, |
988 | unsigned long *removed) | |
989 | { | |
990 | struct rcu_table *t; | |
14044b37 MD |
991 | struct cds_lfht_node *node, *next; |
992 | struct _cds_lfht_node *lookup; | |
24365af7 | 993 | unsigned long nr_dummy = 0; |
273399de MD |
994 | |
995 | *count = 0; | |
996 | *removed = 0; | |
997 | ||
998 | t = rcu_dereference(ht->t); | |
24365af7 MD |
999 | /* Count non-dummy nodes in the table */ |
1000 | lookup = &t->tbl[0][0]; | |
14044b37 | 1001 | node = (struct cds_lfht_node *) lookup; |
273399de | 1002 | do { |
cc4fcb10 | 1003 | next = rcu_dereference(node->p.next); |
273399de | 1004 | if (is_removed(next)) { |
1b81fe1a | 1005 | assert(!is_dummy(next)); |
273399de | 1006 | (*removed)++; |
1b81fe1a | 1007 | } else if (!is_dummy(next)) |
273399de | 1008 | (*count)++; |
24365af7 MD |
1009 | else |
1010 | (nr_dummy)++; | |
273399de MD |
1011 | node = clear_flag(next); |
1012 | } while (node); | |
f0c29ed7 | 1013 | dbg_printf("number of dummy nodes: %lu\n", nr_dummy); |
273399de MD |
1014 | } |
1015 | ||
abc490a1 | 1016 | static |
14044b37 | 1017 | void cds_lfht_free_table_cb(struct rcu_head *head) |
abc490a1 MD |
1018 | { |
1019 | struct rcu_table *t = | |
1020 | caa_container_of(head, struct rcu_table, head); | |
1021 | free(t); | |
1022 | } | |
1023 | ||
1024 | /* called with resize mutex held */ | |
1025 | static | |
14044b37 | 1026 | void _do_cds_lfht_resize(struct cds_lfht *ht) |
464a1ec9 | 1027 | { |
24365af7 | 1028 | unsigned long new_size, old_size, old_order, new_order; |
395270b6 | 1029 | struct rcu_table *new_t, *old_t; |
464a1ec9 | 1030 | |
395270b6 MD |
1031 | old_t = ht->t; |
1032 | old_size = old_t->size; | |
24365af7 | 1033 | old_order = get_count_order_ulong(old_size) + 1; |
464a1ec9 | 1034 | |
f9830efd | 1035 | new_size = CMM_LOAD_SHARED(old_t->resize_target); |
abc490a1 | 1036 | if (old_size == new_size) |
464a1ec9 | 1037 | return; |
24365af7 | 1038 | new_order = get_count_order_ulong(new_size) + 1; |
df44348d | 1039 | printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", |
df03fab8 | 1040 | old_size, old_order, new_size, new_order); |
14044b37 MD |
1041 | new_t = malloc(sizeof(struct cds_lfht) |
1042 | + (new_order * sizeof(struct _cds_lfht_node *))); | |
f000907d MD |
1043 | assert(new_size > old_size); |
1044 | memcpy(&new_t->tbl, &old_t->tbl, | |
14044b37 | 1045 | old_order * sizeof(struct _cds_lfht_node *)); |
24365af7 | 1046 | init_table(ht, new_t, old_order, new_order - old_order); |
f000907d MD |
1047 | /* Changing table and size atomically wrt lookups */ |
1048 | rcu_assign_pointer(ht->t, new_t); | |
14044b37 | 1049 | ht->cds_lfht_call_rcu(&old_t->head, cds_lfht_free_table_cb); |
464a1ec9 MD |
1050 | } |
1051 | ||
abc490a1 | 1052 | static |
f9830efd MD |
1053 | unsigned long resize_target_update(struct rcu_table *t, |
1054 | int growth_order) | |
464a1ec9 | 1055 | { |
f9830efd MD |
1056 | return _uatomic_max(&t->resize_target, |
1057 | t->size << growth_order); | |
464a1ec9 MD |
1058 | } |
1059 | ||
14044b37 | 1060 | void cds_lfht_resize(struct cds_lfht *ht, int growth) |
464a1ec9 | 1061 | { |
f9830efd MD |
1062 | struct rcu_table *t = rcu_dereference(ht->t); |
1063 | unsigned long target_size; | |
1064 | ||
f0c29ed7 MD |
1065 | if (growth < 0) { |
1066 | /* | |
1067 | * Silently refuse to shrink hash table. (not supported) | |
1068 | */ | |
1069 | dbg_printf("shrinking hash table not supported.\n"); | |
1070 | return; | |
1071 | } | |
1072 | ||
f9830efd MD |
1073 | target_size = resize_target_update(t, growth); |
1074 | if (t->size < target_size) { | |
11519af6 | 1075 | CMM_STORE_SHARED(t->resize_initiated, 1); |
f9830efd | 1076 | pthread_mutex_lock(&ht->resize_mutex); |
14044b37 | 1077 | _do_cds_lfht_resize(ht); |
f9830efd MD |
1078 | pthread_mutex_unlock(&ht->resize_mutex); |
1079 | } | |
abc490a1 | 1080 | } |
464a1ec9 | 1081 | |
abc490a1 MD |
1082 | static |
1083 | void do_resize_cb(struct rcu_head *head) | |
1084 | { | |
1085 | struct rcu_resize_work *work = | |
1086 | caa_container_of(head, struct rcu_resize_work, head); | |
14044b37 | 1087 | struct cds_lfht *ht = work->ht; |
abc490a1 MD |
1088 | |
1089 | pthread_mutex_lock(&ht->resize_mutex); | |
14044b37 | 1090 | _do_cds_lfht_resize(ht); |
abc490a1 MD |
1091 | pthread_mutex_unlock(&ht->resize_mutex); |
1092 | free(work); | |
848d4088 MD |
1093 | cmm_smp_mb(); /* finish resize before decrement */ |
1094 | uatomic_dec(&ht->in_progress_resize); | |
464a1ec9 MD |
1095 | } |
1096 | ||
abc490a1 | 1097 | static |
14044b37 | 1098 | void cds_lfht_resize_lazy(struct cds_lfht *ht, struct rcu_table *t, int growth) |
ab7d5fc6 | 1099 | { |
abc490a1 | 1100 | struct rcu_resize_work *work; |
f9830efd | 1101 | unsigned long target_size; |
abc490a1 | 1102 | |
f9830efd | 1103 | target_size = resize_target_update(t, growth); |
11519af6 | 1104 | if (!CMM_LOAD_SHARED(t->resize_initiated) && t->size < target_size) { |
848d4088 MD |
1105 | uatomic_inc(&ht->in_progress_resize); |
1106 | cmm_smp_mb(); /* increment resize count before calling it */ | |
f9830efd MD |
1107 | work = malloc(sizeof(*work)); |
1108 | work->ht = ht; | |
14044b37 | 1109 | ht->cds_lfht_call_rcu(&work->head, do_resize_cb); |
11519af6 | 1110 | CMM_STORE_SHARED(t->resize_initiated, 1); |
f9830efd | 1111 | } |
ab7d5fc6 | 1112 | } |
3171717f | 1113 | |
f8994aee MD |
1114 | #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) |
1115 | ||
1116 | static | |
1117 | unsigned long resize_target_update_count(struct rcu_table *t, | |
1118 | unsigned long count) | |
1119 | { | |
88d05815 | 1120 | return uatomic_set(&t->resize_target, count); |
f8994aee MD |
1121 | } |
1122 | ||
3171717f MD |
1123 | static |
1124 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, struct rcu_table *t, | |
1125 | unsigned long count) | |
1126 | { | |
1127 | struct rcu_resize_work *work; | |
1128 | unsigned long target_size; | |
1129 | ||
1130 | target_size = resize_target_update_count(t, count); | |
1131 | if (!CMM_LOAD_SHARED(t->resize_initiated) && t->size < target_size) { | |
1132 | uatomic_inc(&ht->in_progress_resize); | |
1133 | cmm_smp_mb(); /* increment resize count before calling it */ | |
1134 | work = malloc(sizeof(*work)); | |
1135 | work->ht = ht; | |
1136 | ht->cds_lfht_call_rcu(&work->head, do_resize_cb); | |
1137 | CMM_STORE_SHARED(t->resize_initiated, 1); | |
1138 | } | |
1139 | } | |
f8994aee MD |
1140 | |
1141 | #endif |