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5e28c532 | 1 | /* |
abc490a1 MD |
2 | * rculfhash.c |
3 | * | |
1475579c | 4 | * Userspace RCU library - Lock-Free Resizable RCU Hash Table |
abc490a1 MD |
5 | * |
6 | * Copyright 2010-2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
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 | * | |
1475579c | 32 | * Some specificities of this Lock-Free Resizable RCU Hash Table |
e753ff5a MD |
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. | |
1475579c MD |
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. | |
e753ff5a MD |
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. | |
29e669f6 MD |
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. | |
e753ff5a MD |
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. | |
1475579c MD |
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 | * | | |
f6fdd688 MD |
123 | * 1 | 1 001 100 <- <- |
124 | * | | | | | |
125 | * 2 | | 2 010 010 | | | |
126 | * | | | 3 011 110 | <- | | |
127 | * | | | | | | | | |
1475579c MD |
128 | * 3 -> | | | 4 100 001 | | |
129 | * -> | | 5 101 101 | | |
130 | * -> | 6 110 011 | |
131 | * -> 7 111 111 | |
e753ff5a MD |
132 | */ |
133 | ||
2ed95849 MD |
134 | #define _LGPL_SOURCE |
135 | #include <stdlib.h> | |
e0ba718a MD |
136 | #include <errno.h> |
137 | #include <assert.h> | |
138 | #include <stdio.h> | |
abc490a1 | 139 | #include <stdint.h> |
f000907d | 140 | #include <string.h> |
e0ba718a | 141 | |
df44348d | 142 | #include "config.h" |
2ed95849 | 143 | #include <urcu.h> |
abc490a1 | 144 | #include <urcu-call-rcu.h> |
a42cc659 MD |
145 | #include <urcu/arch.h> |
146 | #include <urcu/uatomic.h> | |
674f7a69 | 147 | #include <urcu/jhash.h> |
a42cc659 | 148 | #include <urcu/compiler.h> |
abc490a1 | 149 | #include <urcu/rculfhash.h> |
5e28c532 | 150 | #include <stdio.h> |
464a1ec9 | 151 | #include <pthread.h> |
44395fb7 | 152 | |
f9830efd | 153 | #ifdef DEBUG |
f0c29ed7 | 154 | #define dbg_printf(fmt, args...) printf("[debug rculfhash] " fmt, ## args) |
f9830efd | 155 | #else |
e753ff5a | 156 | #define dbg_printf(fmt, args...) |
f9830efd MD |
157 | #endif |
158 | ||
f8994aee MD |
159 | /* |
160 | * Per-CPU split-counters lazily update the global counter each 1024 | |
161 | * addition/removal. It automatically keeps track of resize required. | |
162 | * We use the bucket length as indicator for need to expand for small | |
163 | * tables and machines lacking per-cpu data suppport. | |
164 | */ | |
165 | #define COUNT_COMMIT_ORDER 10 | |
6ea6bc67 MD |
166 | #define CHAIN_LEN_TARGET 1 |
167 | #define CHAIN_LEN_RESIZE_THRESHOLD 3 | |
2ed95849 | 168 | |
cd95516d | 169 | /* |
76a73da8 | 170 | * Define the minimum table size. |
cd95516d MD |
171 | */ |
172 | #define MIN_TABLE_SIZE 128 | |
173 | ||
4105056a MD |
174 | #if (CAA_BITS_PER_LONG == 32) |
175 | #define MAX_TABLE_ORDER 32 | |
176 | #else | |
177 | #define MAX_TABLE_ORDER 64 | |
178 | #endif | |
179 | ||
180 | #ifndef min | |
181 | #define min(a, b) ((a) < (b) ? (a) : (b)) | |
182 | #endif | |
183 | ||
abc490a1 MD |
184 | #ifndef max |
185 | #define max(a, b) ((a) > (b) ? (a) : (b)) | |
186 | #endif | |
2ed95849 | 187 | |
d95bd160 MD |
188 | /* |
189 | * The removed flag needs to be updated atomically with the pointer. | |
190 | * The dummy flag does not require to be updated atomically with the | |
191 | * pointer, but it is added as a pointer low bit flag to save space. | |
192 | */ | |
d37166c6 | 193 | #define REMOVED_FLAG (1UL << 0) |
f5596c94 MD |
194 | #define DUMMY_FLAG (1UL << 1) |
195 | #define FLAGS_MASK ((1UL << 2) - 1) | |
d37166c6 | 196 | |
df44348d | 197 | struct ht_items_count { |
3171717f | 198 | unsigned long add, remove; |
df44348d MD |
199 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
200 | ||
1475579c MD |
201 | struct rcu_level { |
202 | struct rcu_head head; | |
203 | struct _cds_lfht_node nodes[0]; | |
204 | }; | |
205 | ||
395270b6 | 206 | struct rcu_table { |
4105056a | 207 | unsigned long size; /* always a power of 2, shared (RCU) */ |
f9830efd | 208 | unsigned long resize_target; |
11519af6 | 209 | int resize_initiated; |
4105056a | 210 | struct rcu_level *tbl[MAX_TABLE_ORDER]; |
395270b6 MD |
211 | }; |
212 | ||
14044b37 | 213 | struct cds_lfht { |
4105056a | 214 | struct rcu_table t; |
14044b37 MD |
215 | cds_lfht_hash_fct hash_fct; |
216 | cds_lfht_compare_fct compare_fct; | |
732ad076 | 217 | unsigned long hash_seed; |
b8af5011 | 218 | int flags; |
5f511391 MD |
219 | /* |
220 | * We need to put the work threads offline (QSBR) when taking this | |
221 | * mutex, because we use synchronize_rcu within this mutex critical | |
222 | * section, which waits on read-side critical sections, and could | |
223 | * therefore cause grace-period deadlock if we hold off RCU G.P. | |
224 | * completion. | |
225 | */ | |
464a1ec9 | 226 | pthread_mutex_t resize_mutex; /* resize mutex: add/del mutex */ |
33c7c748 | 227 | unsigned int in_progress_resize, in_progress_destroy; |
14044b37 | 228 | void (*cds_lfht_call_rcu)(struct rcu_head *head, |
abc490a1 | 229 | void (*func)(struct rcu_head *head)); |
1475579c | 230 | void (*cds_lfht_synchronize_rcu)(void); |
01dbfa62 MD |
231 | void (*cds_lfht_rcu_read_lock)(void); |
232 | void (*cds_lfht_rcu_read_unlock)(void); | |
5f511391 MD |
233 | void (*cds_lfht_rcu_thread_offline)(void); |
234 | void (*cds_lfht_rcu_thread_online)(void); | |
df44348d MD |
235 | unsigned long count; /* global approximate item count */ |
236 | struct ht_items_count *percpu_count; /* per-cpu item count */ | |
2ed95849 MD |
237 | }; |
238 | ||
abc490a1 MD |
239 | struct rcu_resize_work { |
240 | struct rcu_head head; | |
14044b37 | 241 | struct cds_lfht *ht; |
abc490a1 | 242 | }; |
2ed95849 | 243 | |
76a73da8 MD |
244 | static |
245 | struct cds_lfht_node *_cds_lfht_add(struct cds_lfht *ht, | |
246 | unsigned long size, | |
247 | struct cds_lfht_node *node, | |
248 | int unique, int dummy); | |
249 | ||
abc490a1 MD |
250 | /* |
251 | * Algorithm to reverse bits in a word by lookup table, extended to | |
252 | * 64-bit words. | |
f9830efd | 253 | * Source: |
abc490a1 | 254 | * http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable |
f9830efd | 255 | * Originally from Public Domain. |
abc490a1 MD |
256 | */ |
257 | ||
258 | static const uint8_t BitReverseTable256[256] = | |
2ed95849 | 259 | { |
abc490a1 MD |
260 | #define R2(n) (n), (n) + 2*64, (n) + 1*64, (n) + 3*64 |
261 | #define R4(n) R2(n), R2((n) + 2*16), R2((n) + 1*16), R2((n) + 3*16) | |
262 | #define R6(n) R4(n), R4((n) + 2*4 ), R4((n) + 1*4 ), R4((n) + 3*4 ) | |
263 | R6(0), R6(2), R6(1), R6(3) | |
264 | }; | |
265 | #undef R2 | |
266 | #undef R4 | |
267 | #undef R6 | |
2ed95849 | 268 | |
abc490a1 MD |
269 | static |
270 | uint8_t bit_reverse_u8(uint8_t v) | |
271 | { | |
272 | return BitReverseTable256[v]; | |
273 | } | |
ab7d5fc6 | 274 | |
abc490a1 MD |
275 | static __attribute__((unused)) |
276 | uint32_t bit_reverse_u32(uint32_t v) | |
277 | { | |
278 | return ((uint32_t) bit_reverse_u8(v) << 24) | | |
279 | ((uint32_t) bit_reverse_u8(v >> 8) << 16) | | |
280 | ((uint32_t) bit_reverse_u8(v >> 16) << 8) | | |
281 | ((uint32_t) bit_reverse_u8(v >> 24)); | |
2ed95849 MD |
282 | } |
283 | ||
abc490a1 MD |
284 | static __attribute__((unused)) |
285 | uint64_t bit_reverse_u64(uint64_t v) | |
2ed95849 | 286 | { |
abc490a1 MD |
287 | return ((uint64_t) bit_reverse_u8(v) << 56) | |
288 | ((uint64_t) bit_reverse_u8(v >> 8) << 48) | | |
289 | ((uint64_t) bit_reverse_u8(v >> 16) << 40) | | |
290 | ((uint64_t) bit_reverse_u8(v >> 24) << 32) | | |
291 | ((uint64_t) bit_reverse_u8(v >> 32) << 24) | | |
292 | ((uint64_t) bit_reverse_u8(v >> 40) << 16) | | |
293 | ((uint64_t) bit_reverse_u8(v >> 48) << 8) | | |
294 | ((uint64_t) bit_reverse_u8(v >> 56)); | |
295 | } | |
296 | ||
297 | static | |
298 | unsigned long bit_reverse_ulong(unsigned long v) | |
299 | { | |
300 | #if (CAA_BITS_PER_LONG == 32) | |
301 | return bit_reverse_u32(v); | |
302 | #else | |
303 | return bit_reverse_u64(v); | |
304 | #endif | |
305 | } | |
306 | ||
f9830efd | 307 | /* |
24365af7 MD |
308 | * fls: returns the position of the most significant bit. |
309 | * Returns 0 if no bit is set, else returns the position of the most | |
310 | * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit). | |
f9830efd | 311 | */ |
24365af7 MD |
312 | #if defined(__i386) || defined(__x86_64) |
313 | static inline | |
314 | unsigned int fls_u32(uint32_t x) | |
f9830efd | 315 | { |
24365af7 MD |
316 | int r; |
317 | ||
318 | asm("bsrl %1,%0\n\t" | |
319 | "jnz 1f\n\t" | |
320 | "movl $-1,%0\n\t" | |
321 | "1:\n\t" | |
322 | : "=r" (r) : "rm" (x)); | |
323 | return r + 1; | |
324 | } | |
325 | #define HAS_FLS_U32 | |
326 | #endif | |
327 | ||
328 | #if defined(__x86_64) | |
329 | static inline | |
330 | unsigned int fls_u64(uint64_t x) | |
331 | { | |
332 | long r; | |
333 | ||
334 | asm("bsrq %1,%0\n\t" | |
335 | "jnz 1f\n\t" | |
336 | "movq $-1,%0\n\t" | |
337 | "1:\n\t" | |
338 | : "=r" (r) : "rm" (x)); | |
339 | return r + 1; | |
340 | } | |
341 | #define HAS_FLS_U64 | |
342 | #endif | |
343 | ||
344 | #ifndef HAS_FLS_U64 | |
345 | static __attribute__((unused)) | |
346 | unsigned int fls_u64(uint64_t x) | |
347 | { | |
348 | unsigned int r = 64; | |
349 | ||
350 | if (!x) | |
351 | return 0; | |
352 | ||
353 | if (!(x & 0xFFFFFFFF00000000ULL)) { | |
354 | x <<= 32; | |
355 | r -= 32; | |
356 | } | |
357 | if (!(x & 0xFFFF000000000000ULL)) { | |
358 | x <<= 16; | |
359 | r -= 16; | |
360 | } | |
361 | if (!(x & 0xFF00000000000000ULL)) { | |
362 | x <<= 8; | |
363 | r -= 8; | |
364 | } | |
365 | if (!(x & 0xF000000000000000ULL)) { | |
366 | x <<= 4; | |
367 | r -= 4; | |
368 | } | |
369 | if (!(x & 0xC000000000000000ULL)) { | |
370 | x <<= 2; | |
371 | r -= 2; | |
372 | } | |
373 | if (!(x & 0x8000000000000000ULL)) { | |
374 | x <<= 1; | |
375 | r -= 1; | |
376 | } | |
377 | return r; | |
378 | } | |
379 | #endif | |
380 | ||
381 | #ifndef HAS_FLS_U32 | |
382 | static __attribute__((unused)) | |
383 | unsigned int fls_u32(uint32_t x) | |
384 | { | |
385 | unsigned int r = 32; | |
f9830efd | 386 | |
24365af7 MD |
387 | if (!x) |
388 | return 0; | |
389 | if (!(x & 0xFFFF0000U)) { | |
390 | x <<= 16; | |
391 | r -= 16; | |
392 | } | |
393 | if (!(x & 0xFF000000U)) { | |
394 | x <<= 8; | |
395 | r -= 8; | |
396 | } | |
397 | if (!(x & 0xF0000000U)) { | |
398 | x <<= 4; | |
399 | r -= 4; | |
400 | } | |
401 | if (!(x & 0xC0000000U)) { | |
402 | x <<= 2; | |
403 | r -= 2; | |
404 | } | |
405 | if (!(x & 0x80000000U)) { | |
406 | x <<= 1; | |
407 | r -= 1; | |
408 | } | |
409 | return r; | |
410 | } | |
411 | #endif | |
412 | ||
413 | unsigned int fls_ulong(unsigned long x) | |
f9830efd | 414 | { |
24365af7 MD |
415 | #if (CAA_BITS_PER_lONG == 32) |
416 | return fls_u32(x); | |
417 | #else | |
418 | return fls_u64(x); | |
419 | #endif | |
420 | } | |
f9830efd | 421 | |
24365af7 MD |
422 | int get_count_order_u32(uint32_t x) |
423 | { | |
424 | int order; | |
425 | ||
426 | order = fls_u32(x) - 1; | |
427 | if (x & (x - 1)) | |
428 | order++; | |
429 | return order; | |
430 | } | |
431 | ||
432 | int get_count_order_ulong(unsigned long x) | |
433 | { | |
434 | int order; | |
435 | ||
436 | order = fls_ulong(x) - 1; | |
437 | if (x & (x - 1)) | |
438 | order++; | |
439 | return order; | |
f9830efd MD |
440 | } |
441 | ||
98808fb1 MD |
442 | #ifdef POISON_FREE |
443 | #define poison_free(ptr) \ | |
444 | do { \ | |
445 | memset(ptr, 0x42, sizeof(*(ptr))); \ | |
446 | free(ptr); \ | |
447 | } while (0) | |
448 | #else | |
449 | #define poison_free(ptr) free(ptr) | |
450 | #endif | |
451 | ||
f9830efd | 452 | static |
4105056a | 453 | void cds_lfht_resize_lazy(struct cds_lfht *ht, unsigned long size, int growth); |
f9830efd | 454 | |
df44348d MD |
455 | /* |
456 | * If the sched_getcpu() and sysconf(_SC_NPROCESSORS_CONF) calls are | |
457 | * available, then we support hash table item accounting. | |
458 | * In the unfortunate event the number of CPUs reported would be | |
459 | * inaccurate, we use modulo arithmetic on the number of CPUs we got. | |
460 | */ | |
df44348d MD |
461 | #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) |
462 | ||
f8994aee | 463 | static |
4105056a | 464 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, |
f8994aee MD |
465 | unsigned long count); |
466 | ||
df44348d MD |
467 | static long nr_cpus_mask = -1; |
468 | ||
469 | static | |
470 | struct ht_items_count *alloc_per_cpu_items_count(void) | |
471 | { | |
472 | struct ht_items_count *count; | |
473 | ||
474 | switch (nr_cpus_mask) { | |
475 | case -2: | |
476 | return NULL; | |
477 | case -1: | |
478 | { | |
479 | long maxcpus; | |
480 | ||
481 | maxcpus = sysconf(_SC_NPROCESSORS_CONF); | |
482 | if (maxcpus <= 0) { | |
483 | nr_cpus_mask = -2; | |
484 | return NULL; | |
485 | } | |
486 | /* | |
487 | * round up number of CPUs to next power of two, so we | |
488 | * can use & for modulo. | |
489 | */ | |
490 | maxcpus = 1UL << get_count_order_ulong(maxcpus); | |
491 | nr_cpus_mask = maxcpus - 1; | |
492 | } | |
493 | /* Fall-through */ | |
494 | default: | |
495 | return calloc(nr_cpus_mask + 1, sizeof(*count)); | |
496 | } | |
497 | } | |
498 | ||
499 | static | |
500 | void free_per_cpu_items_count(struct ht_items_count *count) | |
501 | { | |
98808fb1 | 502 | poison_free(count); |
df44348d MD |
503 | } |
504 | ||
505 | static | |
506 | int ht_get_cpu(void) | |
507 | { | |
508 | int cpu; | |
509 | ||
510 | assert(nr_cpus_mask >= 0); | |
511 | cpu = sched_getcpu(); | |
512 | if (unlikely(cpu < 0)) | |
513 | return cpu; | |
514 | else | |
515 | return cpu & nr_cpus_mask; | |
516 | } | |
517 | ||
518 | static | |
4105056a | 519 | void ht_count_add(struct cds_lfht *ht, unsigned long size) |
df44348d | 520 | { |
3171717f | 521 | unsigned long percpu_count; |
df44348d MD |
522 | int cpu; |
523 | ||
524 | if (unlikely(!ht->percpu_count)) | |
3171717f | 525 | return; |
df44348d MD |
526 | cpu = ht_get_cpu(); |
527 | if (unlikely(cpu < 0)) | |
3171717f MD |
528 | return; |
529 | percpu_count = uatomic_add_return(&ht->percpu_count[cpu].add, 1); | |
df44348d MD |
530 | if (unlikely(!(percpu_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) { |
531 | unsigned long count; | |
532 | ||
533 | dbg_printf("add percpu %lu\n", percpu_count); | |
534 | count = uatomic_add_return(&ht->count, | |
535 | 1UL << COUNT_COMMIT_ORDER); | |
536 | /* If power of 2 */ | |
537 | if (!(count & (count - 1))) { | |
4105056a | 538 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) < size) |
f8994aee MD |
539 | return; |
540 | dbg_printf("add set global %lu\n", count); | |
4105056a | 541 | cds_lfht_resize_lazy_count(ht, size, |
6ea6bc67 | 542 | count >> (CHAIN_LEN_TARGET - 1)); |
df44348d MD |
543 | } |
544 | } | |
545 | } | |
546 | ||
547 | static | |
4105056a | 548 | void ht_count_remove(struct cds_lfht *ht, unsigned long size) |
df44348d MD |
549 | { |
550 | unsigned long percpu_count; | |
3171717f | 551 | int cpu; |
df44348d | 552 | |
3171717f MD |
553 | if (unlikely(!ht->percpu_count)) |
554 | return; | |
555 | cpu = ht_get_cpu(); | |
556 | if (unlikely(cpu < 0)) | |
557 | return; | |
558 | percpu_count = uatomic_add_return(&ht->percpu_count[cpu].remove, -1); | |
df44348d MD |
559 | if (unlikely(!(percpu_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) { |
560 | unsigned long count; | |
561 | ||
562 | dbg_printf("remove percpu %lu\n", percpu_count); | |
563 | count = uatomic_add_return(&ht->count, | |
3171717f | 564 | -(1UL << COUNT_COMMIT_ORDER)); |
df44348d MD |
565 | /* If power of 2 */ |
566 | if (!(count & (count - 1))) { | |
4105056a | 567 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) >= size) |
f8994aee MD |
568 | return; |
569 | dbg_printf("remove set global %lu\n", count); | |
4105056a | 570 | cds_lfht_resize_lazy_count(ht, size, |
6ea6bc67 | 571 | count >> (CHAIN_LEN_TARGET - 1)); |
df44348d MD |
572 | } |
573 | } | |
574 | } | |
575 | ||
576 | #else /* #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */ | |
577 | ||
578 | static const long nr_cpus_mask = -1; | |
579 | ||
580 | static | |
581 | struct ht_items_count *alloc_per_cpu_items_count(void) | |
582 | { | |
583 | return NULL; | |
584 | } | |
585 | ||
586 | static | |
587 | void free_per_cpu_items_count(struct ht_items_count *count) | |
588 | { | |
589 | } | |
590 | ||
591 | static | |
4105056a | 592 | void ht_count_add(struct cds_lfht *ht, unsigned long size) |
df44348d MD |
593 | { |
594 | } | |
595 | ||
596 | static | |
4105056a | 597 | void ht_count_remove(struct cds_lfht *ht, unsigned long size) |
df44348d MD |
598 | { |
599 | } | |
600 | ||
601 | #endif /* #else #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */ | |
602 | ||
603 | ||
f9830efd | 604 | static |
4105056a | 605 | void check_resize(struct cds_lfht *ht, unsigned long size, uint32_t chain_len) |
f9830efd | 606 | { |
f8994aee MD |
607 | unsigned long count; |
608 | ||
b8af5011 MD |
609 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) |
610 | return; | |
f8994aee MD |
611 | count = uatomic_read(&ht->count); |
612 | /* | |
613 | * Use bucket-local length for small table expand and for | |
614 | * environments lacking per-cpu data support. | |
615 | */ | |
616 | if (count >= (1UL << COUNT_COMMIT_ORDER)) | |
617 | return; | |
24365af7 | 618 | if (chain_len > 100) |
f0c29ed7 | 619 | dbg_printf("WARNING: large chain length: %u.\n", |
24365af7 | 620 | chain_len); |
3390d470 | 621 | if (chain_len >= CHAIN_LEN_RESIZE_THRESHOLD) |
4105056a | 622 | cds_lfht_resize_lazy(ht, size, |
01370f0b | 623 | get_count_order_u32(chain_len - (CHAIN_LEN_TARGET - 1))); |
f9830efd MD |
624 | } |
625 | ||
abc490a1 | 626 | static |
14044b37 | 627 | struct cds_lfht_node *clear_flag(struct cds_lfht_node *node) |
abc490a1 | 628 | { |
14044b37 | 629 | return (struct cds_lfht_node *) (((unsigned long) node) & ~FLAGS_MASK); |
abc490a1 MD |
630 | } |
631 | ||
632 | static | |
14044b37 | 633 | int is_removed(struct cds_lfht_node *node) |
abc490a1 | 634 | { |
d37166c6 | 635 | return ((unsigned long) node) & REMOVED_FLAG; |
abc490a1 MD |
636 | } |
637 | ||
638 | static | |
14044b37 | 639 | struct cds_lfht_node *flag_removed(struct cds_lfht_node *node) |
abc490a1 | 640 | { |
14044b37 | 641 | return (struct cds_lfht_node *) (((unsigned long) node) | REMOVED_FLAG); |
abc490a1 MD |
642 | } |
643 | ||
f5596c94 | 644 | static |
14044b37 | 645 | int is_dummy(struct cds_lfht_node *node) |
f5596c94 MD |
646 | { |
647 | return ((unsigned long) node) & DUMMY_FLAG; | |
648 | } | |
649 | ||
650 | static | |
14044b37 | 651 | struct cds_lfht_node *flag_dummy(struct cds_lfht_node *node) |
f5596c94 | 652 | { |
14044b37 | 653 | return (struct cds_lfht_node *) (((unsigned long) node) | DUMMY_FLAG); |
f5596c94 MD |
654 | } |
655 | ||
abc490a1 | 656 | static |
f9830efd | 657 | unsigned long _uatomic_max(unsigned long *ptr, unsigned long v) |
abc490a1 MD |
658 | { |
659 | unsigned long old1, old2; | |
660 | ||
661 | old1 = uatomic_read(ptr); | |
662 | do { | |
663 | old2 = old1; | |
664 | if (old2 >= v) | |
f9830efd | 665 | return old2; |
abc490a1 | 666 | } while ((old1 = uatomic_cmpxchg(ptr, old2, v)) != old2); |
f9830efd | 667 | return v; |
abc490a1 MD |
668 | } |
669 | ||
1475579c MD |
670 | static |
671 | void cds_lfht_free_level(struct rcu_head *head) | |
672 | { | |
673 | struct rcu_level *l = | |
674 | caa_container_of(head, struct rcu_level, head); | |
98808fb1 | 675 | poison_free(l); |
1475579c MD |
676 | } |
677 | ||
273399de MD |
678 | /* |
679 | * Remove all logically deleted nodes from a bucket up to a certain node key. | |
680 | */ | |
681 | static | |
76a73da8 | 682 | int _cds_lfht_gc_bucket(struct cds_lfht_node *dummy, struct cds_lfht_node *node) |
273399de | 683 | { |
14044b37 | 684 | struct cds_lfht_node *iter_prev, *iter, *next, *new_next; |
273399de | 685 | |
c90201ac MD |
686 | assert(!is_dummy(dummy)); |
687 | assert(!is_removed(dummy)); | |
688 | assert(!is_dummy(node)); | |
689 | assert(!is_removed(node)); | |
273399de MD |
690 | for (;;) { |
691 | iter_prev = dummy; | |
692 | /* We can always skip the dummy node initially */ | |
cc4fcb10 | 693 | iter = rcu_dereference(iter_prev->p.next); |
76a73da8 MD |
694 | if (unlikely(iter == NULL)) { |
695 | /* | |
696 | * We are executing concurrently with a hash table | |
697 | * expand, so we see a dummy node with NULL next value. | |
698 | * Help expand by linking this node into the list and | |
699 | * retry. | |
700 | */ | |
701 | return 1; | |
702 | } | |
cc4fcb10 | 703 | assert(iter_prev->p.reverse_hash <= node->p.reverse_hash); |
bd4db153 MD |
704 | /* |
705 | * We should never be called with dummy (start of chain) | |
706 | * and logically removed node (end of path compression | |
707 | * marker) being the actual same node. This would be a | |
708 | * bug in the algorithm implementation. | |
709 | */ | |
710 | assert(dummy != node); | |
273399de | 711 | for (;;) { |
a2974903 | 712 | if (unlikely(!clear_flag(iter))) |
76a73da8 | 713 | return 0; |
76412f24 | 714 | if (likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash)) |
76a73da8 | 715 | return 0; |
cc4fcb10 | 716 | next = rcu_dereference(clear_flag(iter)->p.next); |
76412f24 | 717 | if (likely(is_removed(next))) |
273399de | 718 | break; |
b453eae1 | 719 | iter_prev = clear_flag(iter); |
273399de MD |
720 | iter = next; |
721 | } | |
722 | assert(!is_removed(iter)); | |
f5596c94 MD |
723 | if (is_dummy(iter)) |
724 | new_next = flag_dummy(clear_flag(next)); | |
725 | else | |
726 | new_next = clear_flag(next); | |
727 | (void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next); | |
273399de | 728 | } |
76a73da8 | 729 | return 0; |
273399de MD |
730 | } |
731 | ||
abc490a1 | 732 | static |
4105056a MD |
733 | struct cds_lfht_node *_cds_lfht_add(struct cds_lfht *ht, |
734 | unsigned long size, | |
735 | struct cds_lfht_node *node, | |
736 | int unique, int dummy) | |
abc490a1 | 737 | { |
14044b37 | 738 | struct cds_lfht_node *iter_prev, *iter, *next, *new_node, *new_next, |
f5596c94 | 739 | *dummy_node; |
14044b37 | 740 | struct _cds_lfht_node *lookup; |
24365af7 | 741 | unsigned long hash, index, order; |
abc490a1 | 742 | |
c90201ac MD |
743 | assert(!is_dummy(node)); |
744 | assert(!is_removed(node)); | |
4105056a | 745 | if (!size) { |
f5596c94 MD |
746 | assert(dummy); |
747 | node->p.next = flag_dummy(NULL); | |
18117871 MD |
748 | return node; /* Initial first add (head) */ |
749 | } | |
cc4fcb10 | 750 | hash = bit_reverse_ulong(node->p.reverse_hash); |
abc490a1 | 751 | for (;;) { |
f9830efd | 752 | uint32_t chain_len = 0; |
abc490a1 | 753 | |
11519af6 MD |
754 | /* |
755 | * iter_prev points to the non-removed node prior to the | |
756 | * insert location. | |
11519af6 | 757 | */ |
4105056a | 758 | index = hash & (size - 1); |
24365af7 | 759 | order = get_count_order_ulong(index + 1); |
4105056a | 760 | lookup = &ht->t.tbl[order]->nodes[index & ((!order ? 0 : (1UL << (order - 1))) - 1)]; |
14044b37 | 761 | iter_prev = (struct cds_lfht_node *) lookup; |
11519af6 | 762 | /* We can always skip the dummy node initially */ |
cc4fcb10 | 763 | iter = rcu_dereference(iter_prev->p.next); |
76a73da8 MD |
764 | if (unlikely(iter == NULL)) { |
765 | /* | |
766 | * We are executing concurrently with a hash table | |
767 | * expand, so we see a dummy node with NULL next value. | |
768 | * Help expand by linking this node into the list and | |
769 | * retry. | |
770 | */ | |
771 | (void) _cds_lfht_add(ht, size >> 1, iter_prev, 0, 1); | |
772 | continue; /* retry */ | |
773 | } | |
cc4fcb10 | 774 | assert(iter_prev->p.reverse_hash <= node->p.reverse_hash); |
abc490a1 | 775 | for (;;) { |
76a73da8 MD |
776 | /* |
777 | * When adding a dummy node, we allow concurrent | |
778 | * add/removal to help. If we find the dummy node in | |
779 | * place, skip its insertion. | |
780 | */ | |
781 | if (unlikely(dummy && clear_flag(iter) == node)) | |
782 | return node; | |
a2974903 | 783 | if (unlikely(!clear_flag(iter))) |
273399de | 784 | goto insert; |
76412f24 | 785 | if (likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash)) |
273399de | 786 | goto insert; |
cc4fcb10 | 787 | next = rcu_dereference(clear_flag(iter)->p.next); |
76412f24 | 788 | if (unlikely(is_removed(next))) |
9dba85be | 789 | goto gc_node; |
e43f23f8 | 790 | if (unique |
1b81fe1a | 791 | && !is_dummy(next) |
e43f23f8 MD |
792 | && !ht->compare_fct(node->key, node->key_len, |
793 | clear_flag(iter)->key, | |
794 | clear_flag(iter)->key_len)) | |
18117871 | 795 | return clear_flag(iter); |
11519af6 | 796 | /* Only account for identical reverse hash once */ |
24365af7 MD |
797 | if (iter_prev->p.reverse_hash != clear_flag(iter)->p.reverse_hash |
798 | && !is_dummy(next)) | |
4105056a | 799 | check_resize(ht, size, ++chain_len); |
11519af6 | 800 | iter_prev = clear_flag(iter); |
273399de | 801 | iter = next; |
abc490a1 | 802 | } |
273399de | 803 | insert: |
7ec59d3b | 804 | assert(node != clear_flag(iter)); |
11519af6 | 805 | assert(!is_removed(iter_prev)); |
c90201ac | 806 | assert(!is_removed(iter)); |
f000907d | 807 | assert(iter_prev != node); |
f5596c94 | 808 | if (!dummy) |
1b81fe1a | 809 | node->p.next = clear_flag(iter); |
f5596c94 | 810 | else |
1b81fe1a | 811 | node->p.next = flag_dummy(clear_flag(iter)); |
f5596c94 MD |
812 | if (is_dummy(iter)) |
813 | new_node = flag_dummy(node); | |
814 | else | |
815 | new_node = node; | |
cc4fcb10 | 816 | if (uatomic_cmpxchg(&iter_prev->p.next, iter, |
f5596c94 | 817 | new_node) != iter) |
273399de | 818 | continue; /* retry */ |
11519af6 | 819 | else |
273399de | 820 | goto gc_end; |
9dba85be MD |
821 | gc_node: |
822 | assert(!is_removed(iter)); | |
f5596c94 MD |
823 | if (is_dummy(iter)) |
824 | new_next = flag_dummy(clear_flag(next)); | |
825 | else | |
826 | new_next = clear_flag(next); | |
827 | (void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next); | |
273399de | 828 | /* retry */ |
464a1ec9 | 829 | } |
273399de MD |
830 | gc_end: |
831 | /* Garbage collect logically removed nodes in the bucket */ | |
4105056a | 832 | index = hash & (size - 1); |
24365af7 | 833 | order = get_count_order_ulong(index + 1); |
4105056a | 834 | lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1)) - 1))]; |
14044b37 | 835 | dummy_node = (struct cds_lfht_node *) lookup; |
76a73da8 MD |
836 | if (_cds_lfht_gc_bucket(dummy_node, node)) { |
837 | /* Help expand */ | |
838 | (void) _cds_lfht_add(ht, size >> 1, dummy_node, 0, 1); | |
839 | goto gc_end; /* retry */ | |
840 | } | |
18117871 | 841 | return node; |
abc490a1 | 842 | } |
464a1ec9 | 843 | |
abc490a1 | 844 | static |
4105056a MD |
845 | int _cds_lfht_remove(struct cds_lfht *ht, unsigned long size, |
846 | struct cds_lfht_node *node, | |
847 | int dummy_removal) | |
abc490a1 | 848 | { |
14044b37 MD |
849 | struct cds_lfht_node *dummy, *next, *old; |
850 | struct _cds_lfht_node *lookup; | |
abc490a1 | 851 | int flagged = 0; |
24365af7 | 852 | unsigned long hash, index, order; |
5e28c532 | 853 | |
7ec59d3b | 854 | /* logically delete the node */ |
c90201ac MD |
855 | assert(!is_dummy(node)); |
856 | assert(!is_removed(node)); | |
cc4fcb10 | 857 | old = rcu_dereference(node->p.next); |
7ec59d3b MD |
858 | do { |
859 | next = old; | |
76412f24 | 860 | if (unlikely(is_removed(next))) |
7ec59d3b | 861 | goto end; |
1475579c MD |
862 | if (dummy_removal) |
863 | assert(is_dummy(next)); | |
864 | else | |
865 | assert(!is_dummy(next)); | |
cc4fcb10 | 866 | old = uatomic_cmpxchg(&node->p.next, next, |
7ec59d3b MD |
867 | flag_removed(next)); |
868 | } while (old != next); | |
869 | ||
870 | /* We performed the (logical) deletion. */ | |
871 | flagged = 1; | |
872 | ||
873 | /* | |
874 | * Ensure that the node is not visible to readers anymore: lookup for | |
273399de MD |
875 | * the node, and remove it (along with any other logically removed node) |
876 | * if found. | |
11519af6 | 877 | */ |
76a73da8 | 878 | gc_retry: |
cc4fcb10 | 879 | hash = bit_reverse_ulong(node->p.reverse_hash); |
4105056a MD |
880 | assert(size > 0); |
881 | index = hash & (size - 1); | |
24365af7 | 882 | order = get_count_order_ulong(index + 1); |
4105056a | 883 | lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1)) - 1))]; |
14044b37 | 884 | dummy = (struct cds_lfht_node *) lookup; |
76a73da8 MD |
885 | if (_cds_lfht_gc_bucket(dummy, node)) { |
886 | /* Help expand */ | |
887 | (void) _cds_lfht_add(ht, size >> 1, dummy, 0, 1); | |
888 | goto gc_retry; /* retry */ | |
889 | } | |
2ed95849 | 890 | end: |
11519af6 MD |
891 | /* |
892 | * Only the flagging action indicated that we (and no other) | |
893 | * removed the node from the hash. | |
894 | */ | |
7ec59d3b | 895 | if (flagged) { |
cc4fcb10 | 896 | assert(is_removed(rcu_dereference(node->p.next))); |
11519af6 | 897 | return 0; |
7ec59d3b | 898 | } else |
11519af6 | 899 | return -ENOENT; |
abc490a1 | 900 | } |
2ed95849 | 901 | |
4105056a MD |
902 | static |
903 | void init_table_hash(struct cds_lfht *ht, unsigned long i, | |
904 | unsigned long len) | |
905 | { | |
906 | unsigned long j; | |
907 | ||
908 | for (j = 0; j < len; j++) { | |
909 | struct cds_lfht_node *new_node = | |
910 | (struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j]; | |
911 | ||
912 | dbg_printf("init hash entry: i %lu j %lu hash %lu\n", | |
913 | i, j, !i ? 0 : (1UL << (i - 1)) + j); | |
914 | new_node->p.reverse_hash = | |
915 | bit_reverse_ulong(!i ? 0 : (1UL << (i - 1)) + j); | |
916 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
917 | break; | |
918 | } | |
919 | } | |
920 | ||
e8de508e MD |
921 | /* |
922 | * Holding RCU read lock to protect _cds_lfht_add against memory | |
923 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
924 | * problem). | |
925 | */ | |
4105056a MD |
926 | static |
927 | void init_table_link(struct cds_lfht *ht, unsigned long i, unsigned long len) | |
928 | { | |
929 | unsigned long j; | |
930 | ||
5f511391 | 931 | ht->cds_lfht_rcu_thread_online(); |
4105056a MD |
932 | ht->cds_lfht_rcu_read_lock(); |
933 | for (j = 0; j < len; j++) { | |
934 | struct cds_lfht_node *new_node = | |
935 | (struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j]; | |
936 | ||
937 | dbg_printf("init link: i %lu j %lu hash %lu\n", | |
938 | i, j, !i ? 0 : (1UL << (i - 1)) + j); | |
939 | (void) _cds_lfht_add(ht, !i ? 0 : (1UL << (i - 1)), | |
940 | new_node, 0, 1); | |
941 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
942 | break; | |
943 | } | |
944 | ht->cds_lfht_rcu_read_unlock(); | |
5f511391 | 945 | ht->cds_lfht_rcu_thread_offline(); |
4105056a MD |
946 | } |
947 | ||
abc490a1 | 948 | static |
4105056a | 949 | void init_table(struct cds_lfht *ht, |
24365af7 MD |
950 | unsigned long first_order, unsigned long len_order) |
951 | { | |
952 | unsigned long i, end_order; | |
953 | ||
f0c29ed7 | 954 | dbg_printf("init table: first_order %lu end_order %lu\n", |
24365af7 MD |
955 | first_order, first_order + len_order); |
956 | end_order = first_order + len_order; | |
24365af7 | 957 | for (i = first_order; i < end_order; i++) { |
4105056a | 958 | unsigned long len; |
24365af7 MD |
959 | |
960 | len = !i ? 1 : 1UL << (i - 1); | |
f0c29ed7 | 961 | dbg_printf("init order %lu len: %lu\n", i, len); |
4d676753 MD |
962 | |
963 | /* Stop expand if the resize target changes under us */ | |
964 | if (CMM_LOAD_SHARED(ht->t.resize_target) < (!i ? 1 : (1UL << i))) | |
965 | break; | |
966 | ||
4105056a | 967 | ht->t.tbl[i] = calloc(1, sizeof(struct rcu_level) |
1475579c | 968 | + (len * sizeof(struct _cds_lfht_node))); |
4105056a MD |
969 | |
970 | /* Set all dummy nodes reverse hash values for a level */ | |
971 | init_table_hash(ht, i, len); | |
972 | ||
76a73da8 MD |
973 | /* |
974 | * Update table size. At this point, concurrent add/remove see | |
975 | * dummy nodes with correctly initialized reverse hash value, | |
976 | * but with NULL next pointers. If they do, they can help us | |
977 | * link the dummy nodes into the list and retry. | |
978 | */ | |
979 | cmm_smp_wmb(); /* populate data before RCU size */ | |
980 | CMM_STORE_SHARED(ht->t.size, !i ? 1 : (1UL << i)); | |
981 | ||
4105056a MD |
982 | /* |
983 | * Link all dummy nodes into the table. Concurrent | |
984 | * add/remove are helping us. | |
985 | */ | |
986 | init_table_link(ht, i, len); | |
987 | ||
4105056a MD |
988 | dbg_printf("init new size: %lu\n", !i ? 1 : (1UL << i)); |
989 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
990 | break; | |
991 | } | |
992 | } | |
993 | ||
e8de508e MD |
994 | /* |
995 | * Holding RCU read lock to protect _cds_lfht_remove against memory | |
996 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
997 | * problem). | |
998 | * For a single level, we logically remove and garbage collect each node. | |
999 | * | |
1000 | * As a design choice, we perform logical removal and garbage collection on a | |
1001 | * node-per-node basis to simplify this algorithm. We also assume keeping good | |
1002 | * cache locality of the operation would overweight possible performance gain | |
1003 | * that could be achieved by batching garbage collection for multiple levels. | |
1004 | * However, this would have to be justified by benchmarks. | |
1005 | * | |
1006 | * Concurrent removal and add operations are helping us perform garbage | |
1007 | * collection of logically removed nodes. We guarantee that all logically | |
1008 | * removed nodes have been garbage-collected (unlinked) before call_rcu is | |
1009 | * invoked to free a hole level of dummy nodes (after a grace period). | |
1010 | * | |
1011 | * Logical removal and garbage collection can therefore be done in batch or on a | |
1012 | * node-per-node basis, as long as the guarantee above holds. | |
1013 | */ | |
4105056a MD |
1014 | static |
1015 | void remove_table(struct cds_lfht *ht, unsigned long i, unsigned long len) | |
1016 | { | |
1017 | unsigned long j; | |
1018 | ||
5f511391 | 1019 | ht->cds_lfht_rcu_thread_online(); |
4105056a MD |
1020 | ht->cds_lfht_rcu_read_lock(); |
1021 | for (j = 0; j < len; j++) { | |
1022 | struct cds_lfht_node *fini_node = | |
1023 | (struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j]; | |
1024 | ||
1025 | dbg_printf("remove entry: i %lu j %lu hash %lu\n", | |
1026 | i, j, !i ? 0 : (1UL << (i - 1)) + j); | |
1027 | fini_node->p.reverse_hash = | |
1028 | bit_reverse_ulong(!i ? 0 : (1UL << (i - 1)) + j); | |
1029 | (void) _cds_lfht_remove(ht, !i ? 0 : (1UL << (i - 1)), | |
1030 | fini_node, 1); | |
33c7c748 MD |
1031 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
1032 | break; | |
abc490a1 | 1033 | } |
4105056a | 1034 | ht->cds_lfht_rcu_read_unlock(); |
5f511391 | 1035 | ht->cds_lfht_rcu_thread_offline(); |
2ed95849 MD |
1036 | } |
1037 | ||
1475579c | 1038 | static |
4105056a | 1039 | void fini_table(struct cds_lfht *ht, |
1475579c MD |
1040 | unsigned long first_order, unsigned long len_order) |
1041 | { | |
1042 | long i, end_order; | |
1043 | ||
1044 | dbg_printf("fini table: first_order %lu end_order %lu\n", | |
1045 | first_order, first_order + len_order); | |
1046 | end_order = first_order + len_order; | |
1047 | assert(first_order > 0); | |
1475579c | 1048 | for (i = end_order - 1; i >= first_order; i--) { |
4105056a | 1049 | unsigned long len; |
1475579c MD |
1050 | |
1051 | len = !i ? 1 : 1UL << (i - 1); | |
1052 | dbg_printf("fini order %lu len: %lu\n", i, len); | |
4105056a | 1053 | |
4d676753 MD |
1054 | /* Stop shrink if the resize target changes under us */ |
1055 | if (CMM_LOAD_SHARED(ht->t.resize_target) > (1UL << (i - 1))) | |
1056 | break; | |
1057 | ||
1058 | cmm_smp_wmb(); /* populate data before RCU size */ | |
1059 | CMM_STORE_SHARED(ht->t.size, 1UL << (i - 1)); | |
1060 | ||
1061 | /* | |
1062 | * We need to wait for all add operations to reach Q.S. (and | |
1063 | * thus use the new table for lookups) before we can start | |
1064 | * releasing the old dummy nodes. Otherwise their lookup will | |
1065 | * return a logically removed node as insert position. | |
1066 | */ | |
1067 | ht->cds_lfht_synchronize_rcu(); | |
1068 | ||
21263e21 | 1069 | /* |
4105056a MD |
1070 | * Set "removed" flag in dummy nodes about to be removed. |
1071 | * Unlink all now-logically-removed dummy node pointers. | |
1072 | * Concurrent add/remove operation are helping us doing | |
1073 | * the gc. | |
21263e21 | 1074 | */ |
4105056a MD |
1075 | remove_table(ht, i, len); |
1076 | ||
1077 | ht->cds_lfht_call_rcu(&ht->t.tbl[i]->head, cds_lfht_free_level); | |
1078 | ||
1079 | dbg_printf("fini new size: %lu\n", 1UL << i); | |
1475579c MD |
1080 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
1081 | break; | |
1082 | } | |
1475579c MD |
1083 | } |
1084 | ||
14044b37 MD |
1085 | struct cds_lfht *cds_lfht_new(cds_lfht_hash_fct hash_fct, |
1086 | cds_lfht_compare_fct compare_fct, | |
1087 | unsigned long hash_seed, | |
1088 | unsigned long init_size, | |
b8af5011 | 1089 | int flags, |
14044b37 | 1090 | void (*cds_lfht_call_rcu)(struct rcu_head *head, |
1475579c | 1091 | void (*func)(struct rcu_head *head)), |
01dbfa62 MD |
1092 | void (*cds_lfht_synchronize_rcu)(void), |
1093 | void (*cds_lfht_rcu_read_lock)(void), | |
5f511391 MD |
1094 | void (*cds_lfht_rcu_read_unlock)(void), |
1095 | void (*cds_lfht_rcu_thread_offline)(void), | |
1096 | void (*cds_lfht_rcu_thread_online)(void)) | |
abc490a1 | 1097 | { |
14044b37 | 1098 | struct cds_lfht *ht; |
24365af7 | 1099 | unsigned long order; |
abc490a1 | 1100 | |
8129be4e | 1101 | /* init_size must be power of two */ |
49619ea0 | 1102 | if (init_size && (init_size & (init_size - 1))) |
8129be4e | 1103 | return NULL; |
14044b37 | 1104 | ht = calloc(1, sizeof(struct cds_lfht)); |
abc490a1 | 1105 | ht->hash_fct = hash_fct; |
732ad076 MD |
1106 | ht->compare_fct = compare_fct; |
1107 | ht->hash_seed = hash_seed; | |
14044b37 | 1108 | ht->cds_lfht_call_rcu = cds_lfht_call_rcu; |
1475579c | 1109 | ht->cds_lfht_synchronize_rcu = cds_lfht_synchronize_rcu; |
01dbfa62 MD |
1110 | ht->cds_lfht_rcu_read_lock = cds_lfht_rcu_read_lock; |
1111 | ht->cds_lfht_rcu_read_unlock = cds_lfht_rcu_read_unlock; | |
5f511391 MD |
1112 | ht->cds_lfht_rcu_thread_offline = cds_lfht_rcu_thread_offline; |
1113 | ht->cds_lfht_rcu_thread_online = cds_lfht_rcu_thread_online; | |
df44348d | 1114 | ht->percpu_count = alloc_per_cpu_items_count(); |
abc490a1 MD |
1115 | /* this mutex should not nest in read-side C.S. */ |
1116 | pthread_mutex_init(&ht->resize_mutex, NULL); | |
cd95516d | 1117 | order = get_count_order_ulong(max(init_size, MIN_TABLE_SIZE)) + 1; |
b8af5011 | 1118 | ht->flags = flags; |
5f511391 | 1119 | ht->cds_lfht_rcu_thread_offline(); |
f000907d | 1120 | pthread_mutex_lock(&ht->resize_mutex); |
4d676753 | 1121 | ht->t.resize_target = 1UL << (order - 1); |
4105056a | 1122 | init_table(ht, 0, order); |
f000907d | 1123 | pthread_mutex_unlock(&ht->resize_mutex); |
5f511391 | 1124 | ht->cds_lfht_rcu_thread_online(); |
abc490a1 MD |
1125 | return ht; |
1126 | } | |
1127 | ||
14044b37 | 1128 | struct cds_lfht_node *cds_lfht_lookup(struct cds_lfht *ht, void *key, size_t key_len) |
2ed95849 | 1129 | { |
14044b37 MD |
1130 | struct cds_lfht_node *node, *next; |
1131 | struct _cds_lfht_node *lookup; | |
4105056a | 1132 | unsigned long hash, reverse_hash, index, order, size; |
2ed95849 | 1133 | |
732ad076 | 1134 | hash = ht->hash_fct(key, key_len, ht->hash_seed); |
abc490a1 | 1135 | reverse_hash = bit_reverse_ulong(hash); |
464a1ec9 | 1136 | |
4105056a MD |
1137 | size = rcu_dereference(ht->t.size); |
1138 | index = hash & (size - 1); | |
24365af7 | 1139 | order = get_count_order_ulong(index + 1); |
4105056a | 1140 | lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1))) - 1)]; |
f0c29ed7 | 1141 | dbg_printf("lookup hash %lu index %lu order %lu aridx %lu\n", |
554c284e | 1142 | hash, index, order, index & (!order ? 0 : ((1UL << (order - 1)) - 1))); |
14044b37 | 1143 | node = (struct cds_lfht_node *) lookup; |
2ed95849 | 1144 | for (;;) { |
abc490a1 MD |
1145 | if (unlikely(!node)) |
1146 | break; | |
cc4fcb10 | 1147 | if (unlikely(node->p.reverse_hash > reverse_hash)) { |
abc490a1 MD |
1148 | node = NULL; |
1149 | break; | |
2ed95849 | 1150 | } |
1b81fe1a MD |
1151 | next = rcu_dereference(node->p.next); |
1152 | if (likely(!is_removed(next)) | |
1153 | && !is_dummy(next) | |
49c2e2d6 | 1154 | && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) { |
273399de | 1155 | break; |
2ed95849 | 1156 | } |
1b81fe1a | 1157 | node = clear_flag(next); |
2ed95849 | 1158 | } |
1b81fe1a | 1159 | assert(!node || !is_dummy(rcu_dereference(node->p.next))); |
abc490a1 MD |
1160 | return node; |
1161 | } | |
e0ba718a | 1162 | |
a481e5ff MD |
1163 | struct cds_lfht_node *cds_lfht_next(struct cds_lfht *ht, |
1164 | struct cds_lfht_node *node) | |
1165 | { | |
1166 | struct cds_lfht_node *next; | |
1167 | unsigned long reverse_hash; | |
1168 | void *key; | |
1169 | size_t key_len; | |
1170 | ||
1171 | reverse_hash = node->p.reverse_hash; | |
1172 | key = node->key; | |
1173 | key_len = node->key_len; | |
1174 | next = rcu_dereference(node->p.next); | |
1175 | node = clear_flag(next); | |
1176 | ||
1177 | for (;;) { | |
1178 | if (unlikely(!node)) | |
1179 | break; | |
1180 | if (unlikely(node->p.reverse_hash > reverse_hash)) { | |
1181 | node = NULL; | |
1182 | break; | |
1183 | } | |
1184 | next = rcu_dereference(node->p.next); | |
1185 | if (likely(!is_removed(next)) | |
1186 | && !is_dummy(next) | |
1187 | && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) { | |
1188 | break; | |
1189 | } | |
1190 | node = clear_flag(next); | |
1191 | } | |
1192 | assert(!node || !is_dummy(rcu_dereference(node->p.next))); | |
1193 | return node; | |
1194 | } | |
1195 | ||
14044b37 | 1196 | void cds_lfht_add(struct cds_lfht *ht, struct cds_lfht_node *node) |
abc490a1 | 1197 | { |
4105056a | 1198 | unsigned long hash, size; |
ab7d5fc6 | 1199 | |
49c2e2d6 | 1200 | hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed); |
cc4fcb10 | 1201 | node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash); |
2ed95849 | 1202 | |
4105056a MD |
1203 | size = rcu_dereference(ht->t.size); |
1204 | (void) _cds_lfht_add(ht, size, node, 0, 0); | |
1205 | ht_count_add(ht, size); | |
3eca1b8c MD |
1206 | } |
1207 | ||
14044b37 MD |
1208 | struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, |
1209 | struct cds_lfht_node *node) | |
3eca1b8c | 1210 | { |
4105056a | 1211 | unsigned long hash, size; |
df44348d | 1212 | struct cds_lfht_node *ret; |
3eca1b8c | 1213 | |
49c2e2d6 | 1214 | hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed); |
cc4fcb10 | 1215 | node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash); |
3eca1b8c | 1216 | |
4105056a MD |
1217 | size = rcu_dereference(ht->t.size); |
1218 | ret = _cds_lfht_add(ht, size, node, 1, 0); | |
df44348d | 1219 | if (ret != node) |
4105056a | 1220 | ht_count_add(ht, size); |
df44348d | 1221 | return ret; |
2ed95849 MD |
1222 | } |
1223 | ||
14044b37 | 1224 | int cds_lfht_remove(struct cds_lfht *ht, struct cds_lfht_node *node) |
2ed95849 | 1225 | { |
4105056a | 1226 | unsigned long size; |
df44348d | 1227 | int ret; |
abc490a1 | 1228 | |
4105056a MD |
1229 | size = rcu_dereference(ht->t.size); |
1230 | ret = _cds_lfht_remove(ht, size, node, 0); | |
df44348d | 1231 | if (!ret) |
4105056a | 1232 | ht_count_remove(ht, size); |
df44348d | 1233 | return ret; |
2ed95849 | 1234 | } |
ab7d5fc6 | 1235 | |
abc490a1 | 1236 | static |
14044b37 | 1237 | int cds_lfht_delete_dummy(struct cds_lfht *ht) |
674f7a69 | 1238 | { |
14044b37 MD |
1239 | struct cds_lfht_node *node; |
1240 | struct _cds_lfht_node *lookup; | |
4105056a | 1241 | unsigned long order, i, size; |
674f7a69 | 1242 | |
abc490a1 | 1243 | /* Check that the table is empty */ |
4105056a | 1244 | lookup = &ht->t.tbl[0]->nodes[0]; |
14044b37 | 1245 | node = (struct cds_lfht_node *) lookup; |
abc490a1 | 1246 | do { |
1b81fe1a MD |
1247 | node = clear_flag(node)->p.next; |
1248 | if (!is_dummy(node)) | |
abc490a1 | 1249 | return -EPERM; |
273399de | 1250 | assert(!is_removed(node)); |
a2974903 | 1251 | } while (clear_flag(node)); |
4105056a MD |
1252 | /* |
1253 | * size accessed without rcu_dereference because hash table is | |
1254 | * being destroyed. | |
1255 | */ | |
1256 | size = ht->t.size; | |
abc490a1 | 1257 | /* Internal sanity check: all nodes left should be dummy */ |
4105056a | 1258 | for (order = 0; order < get_count_order_ulong(size) + 1; order++) { |
24365af7 MD |
1259 | unsigned long len; |
1260 | ||
1261 | len = !order ? 1 : 1UL << (order - 1); | |
1262 | for (i = 0; i < len; i++) { | |
f0c29ed7 | 1263 | dbg_printf("delete order %lu i %lu hash %lu\n", |
24365af7 | 1264 | order, i, |
4105056a MD |
1265 | bit_reverse_ulong(ht->t.tbl[order]->nodes[i].reverse_hash)); |
1266 | assert(is_dummy(ht->t.tbl[order]->nodes[i].next)); | |
24365af7 | 1267 | } |
4105056a | 1268 | poison_free(ht->t.tbl[order]); |
674f7a69 | 1269 | } |
abc490a1 | 1270 | return 0; |
674f7a69 MD |
1271 | } |
1272 | ||
1273 | /* | |
1274 | * Should only be called when no more concurrent readers nor writers can | |
1275 | * possibly access the table. | |
1276 | */ | |
14044b37 | 1277 | int cds_lfht_destroy(struct cds_lfht *ht) |
674f7a69 | 1278 | { |
5e28c532 MD |
1279 | int ret; |
1280 | ||
848d4088 | 1281 | /* Wait for in-flight resize operations to complete */ |
33c7c748 | 1282 | CMM_STORE_SHARED(ht->in_progress_destroy, 1); |
848d4088 MD |
1283 | while (uatomic_read(&ht->in_progress_resize)) |
1284 | poll(NULL, 0, 100); /* wait for 100ms */ | |
14044b37 | 1285 | ret = cds_lfht_delete_dummy(ht); |
abc490a1 MD |
1286 | if (ret) |
1287 | return ret; | |
df44348d | 1288 | free_per_cpu_items_count(ht->percpu_count); |
98808fb1 | 1289 | poison_free(ht); |
5e28c532 | 1290 | return ret; |
674f7a69 MD |
1291 | } |
1292 | ||
14044b37 | 1293 | void cds_lfht_count_nodes(struct cds_lfht *ht, |
273399de MD |
1294 | unsigned long *count, |
1295 | unsigned long *removed) | |
1296 | { | |
14044b37 MD |
1297 | struct cds_lfht_node *node, *next; |
1298 | struct _cds_lfht_node *lookup; | |
24365af7 | 1299 | unsigned long nr_dummy = 0; |
273399de MD |
1300 | |
1301 | *count = 0; | |
1302 | *removed = 0; | |
1303 | ||
24365af7 | 1304 | /* Count non-dummy nodes in the table */ |
4105056a | 1305 | lookup = &ht->t.tbl[0]->nodes[0]; |
14044b37 | 1306 | node = (struct cds_lfht_node *) lookup; |
273399de | 1307 | do { |
cc4fcb10 | 1308 | next = rcu_dereference(node->p.next); |
273399de | 1309 | if (is_removed(next)) { |
1b81fe1a | 1310 | assert(!is_dummy(next)); |
273399de | 1311 | (*removed)++; |
1b81fe1a | 1312 | } else if (!is_dummy(next)) |
273399de | 1313 | (*count)++; |
24365af7 MD |
1314 | else |
1315 | (nr_dummy)++; | |
273399de MD |
1316 | node = clear_flag(next); |
1317 | } while (node); | |
f0c29ed7 | 1318 | dbg_printf("number of dummy nodes: %lu\n", nr_dummy); |
273399de MD |
1319 | } |
1320 | ||
1475579c | 1321 | /* called with resize mutex held */ |
abc490a1 | 1322 | static |
4105056a | 1323 | void _do_cds_lfht_grow(struct cds_lfht *ht, |
1475579c | 1324 | unsigned long old_size, unsigned long new_size) |
abc490a1 | 1325 | { |
1475579c | 1326 | unsigned long old_order, new_order; |
1475579c MD |
1327 | |
1328 | old_order = get_count_order_ulong(old_size) + 1; | |
1329 | new_order = get_count_order_ulong(new_size) + 1; | |
1330 | printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", | |
1331 | old_size, old_order, new_size, new_order); | |
1475579c | 1332 | assert(new_size > old_size); |
4105056a | 1333 | init_table(ht, old_order, new_order - old_order); |
abc490a1 MD |
1334 | } |
1335 | ||
1336 | /* called with resize mutex held */ | |
1337 | static | |
4105056a | 1338 | void _do_cds_lfht_shrink(struct cds_lfht *ht, |
1475579c | 1339 | unsigned long old_size, unsigned long new_size) |
464a1ec9 | 1340 | { |
1475579c | 1341 | unsigned long old_order, new_order; |
464a1ec9 | 1342 | |
cd95516d | 1343 | new_size = max(new_size, MIN_TABLE_SIZE); |
24365af7 | 1344 | old_order = get_count_order_ulong(old_size) + 1; |
24365af7 | 1345 | new_order = get_count_order_ulong(new_size) + 1; |
df44348d | 1346 | printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", |
df03fab8 | 1347 | old_size, old_order, new_size, new_order); |
1475579c | 1348 | assert(new_size < old_size); |
1475579c | 1349 | |
4105056a MD |
1350 | /* Remove and unlink all dummy nodes to remove. */ |
1351 | fini_table(ht, new_order, old_order - new_order); | |
464a1ec9 MD |
1352 | } |
1353 | ||
1475579c MD |
1354 | |
1355 | /* called with resize mutex held */ | |
1356 | static | |
1357 | void _do_cds_lfht_resize(struct cds_lfht *ht) | |
1358 | { | |
1359 | unsigned long new_size, old_size; | |
4105056a MD |
1360 | |
1361 | /* | |
1362 | * Resize table, re-do if the target size has changed under us. | |
1363 | */ | |
1364 | do { | |
1365 | ht->t.resize_initiated = 1; | |
1366 | old_size = ht->t.size; | |
1367 | new_size = CMM_LOAD_SHARED(ht->t.resize_target); | |
1368 | if (old_size < new_size) | |
1369 | _do_cds_lfht_grow(ht, old_size, new_size); | |
1370 | else if (old_size > new_size) | |
1371 | _do_cds_lfht_shrink(ht, old_size, new_size); | |
1372 | ht->t.resize_initiated = 0; | |
1373 | /* write resize_initiated before read resize_target */ | |
1374 | cmm_smp_mb(); | |
4d676753 | 1375 | } while (ht->t.size != CMM_LOAD_SHARED(ht->t.resize_target)); |
1475579c MD |
1376 | } |
1377 | ||
abc490a1 | 1378 | static |
4105056a | 1379 | unsigned long resize_target_update(struct cds_lfht *ht, unsigned long size, |
f9830efd | 1380 | int growth_order) |
464a1ec9 | 1381 | { |
4105056a MD |
1382 | return _uatomic_max(&ht->t.resize_target, |
1383 | size << growth_order); | |
464a1ec9 MD |
1384 | } |
1385 | ||
1475579c | 1386 | static |
4105056a | 1387 | void resize_target_update_count(struct cds_lfht *ht, |
b8af5011 | 1388 | unsigned long count) |
1475579c | 1389 | { |
cd95516d | 1390 | count = max(count, MIN_TABLE_SIZE); |
4105056a | 1391 | uatomic_set(&ht->t.resize_target, count); |
1475579c MD |
1392 | } |
1393 | ||
1394 | void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size) | |
464a1ec9 | 1395 | { |
4105056a MD |
1396 | resize_target_update_count(ht, new_size); |
1397 | CMM_STORE_SHARED(ht->t.resize_initiated, 1); | |
5f511391 | 1398 | ht->cds_lfht_rcu_thread_offline(); |
1475579c MD |
1399 | pthread_mutex_lock(&ht->resize_mutex); |
1400 | _do_cds_lfht_resize(ht); | |
1401 | pthread_mutex_unlock(&ht->resize_mutex); | |
5f511391 | 1402 | ht->cds_lfht_rcu_thread_online(); |
abc490a1 | 1403 | } |
464a1ec9 | 1404 | |
abc490a1 MD |
1405 | static |
1406 | void do_resize_cb(struct rcu_head *head) | |
1407 | { | |
1408 | struct rcu_resize_work *work = | |
1409 | caa_container_of(head, struct rcu_resize_work, head); | |
14044b37 | 1410 | struct cds_lfht *ht = work->ht; |
abc490a1 | 1411 | |
5f511391 | 1412 | ht->cds_lfht_rcu_thread_offline(); |
abc490a1 | 1413 | pthread_mutex_lock(&ht->resize_mutex); |
14044b37 | 1414 | _do_cds_lfht_resize(ht); |
abc490a1 | 1415 | pthread_mutex_unlock(&ht->resize_mutex); |
5f511391 | 1416 | ht->cds_lfht_rcu_thread_online(); |
98808fb1 | 1417 | poison_free(work); |
848d4088 MD |
1418 | cmm_smp_mb(); /* finish resize before decrement */ |
1419 | uatomic_dec(&ht->in_progress_resize); | |
464a1ec9 MD |
1420 | } |
1421 | ||
abc490a1 | 1422 | static |
4105056a | 1423 | void cds_lfht_resize_lazy(struct cds_lfht *ht, unsigned long size, int growth) |
ab7d5fc6 | 1424 | { |
abc490a1 | 1425 | struct rcu_resize_work *work; |
f9830efd | 1426 | unsigned long target_size; |
abc490a1 | 1427 | |
4105056a MD |
1428 | target_size = resize_target_update(ht, size, growth); |
1429 | /* Store resize_target before read resize_initiated */ | |
1430 | cmm_smp_mb(); | |
1431 | if (!CMM_LOAD_SHARED(ht->t.resize_initiated) && size < target_size) { | |
848d4088 MD |
1432 | uatomic_inc(&ht->in_progress_resize); |
1433 | cmm_smp_mb(); /* increment resize count before calling it */ | |
f9830efd MD |
1434 | work = malloc(sizeof(*work)); |
1435 | work->ht = ht; | |
14044b37 | 1436 | ht->cds_lfht_call_rcu(&work->head, do_resize_cb); |
4105056a | 1437 | CMM_STORE_SHARED(ht->t.resize_initiated, 1); |
f9830efd | 1438 | } |
ab7d5fc6 | 1439 | } |
3171717f | 1440 | |
f8994aee MD |
1441 | #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) |
1442 | ||
3171717f | 1443 | static |
4105056a | 1444 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, |
3171717f MD |
1445 | unsigned long count) |
1446 | { | |
1447 | struct rcu_resize_work *work; | |
3171717f | 1448 | |
b8af5011 MD |
1449 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) |
1450 | return; | |
4105056a MD |
1451 | resize_target_update_count(ht, count); |
1452 | /* Store resize_target before read resize_initiated */ | |
1453 | cmm_smp_mb(); | |
1454 | if (!CMM_LOAD_SHARED(ht->t.resize_initiated)) { | |
3171717f MD |
1455 | uatomic_inc(&ht->in_progress_resize); |
1456 | cmm_smp_mb(); /* increment resize count before calling it */ | |
1457 | work = malloc(sizeof(*work)); | |
1458 | work->ht = ht; | |
1459 | ht->cds_lfht_call_rcu(&work->head, do_resize_cb); | |
4105056a | 1460 | CMM_STORE_SHARED(ht->t.resize_initiated, 1); |
3171717f MD |
1461 | } |
1462 | } | |
f8994aee MD |
1463 | |
1464 | #endif |