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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 MD |
169 | /* |
170 | * Define the minimum table size. Protects against hash table resize overload | |
171 | * when too many entries are added quickly before the resize can complete. | |
172 | * This is especially the case if the table could be shrinked to a size of 1. | |
173 | * TODO: we might want to make the add/remove operations help the resize to | |
174 | * add or remove dummy nodes when a resize is ongoing to ensure upper-bound on | |
175 | * chain length. | |
176 | */ | |
177 | #define MIN_TABLE_SIZE 128 | |
178 | ||
4105056a MD |
179 | #if (CAA_BITS_PER_LONG == 32) |
180 | #define MAX_TABLE_ORDER 32 | |
181 | #else | |
182 | #define MAX_TABLE_ORDER 64 | |
183 | #endif | |
184 | ||
185 | #ifndef min | |
186 | #define min(a, b) ((a) < (b) ? (a) : (b)) | |
187 | #endif | |
188 | ||
abc490a1 MD |
189 | #ifndef max |
190 | #define max(a, b) ((a) > (b) ? (a) : (b)) | |
191 | #endif | |
2ed95849 | 192 | |
d95bd160 MD |
193 | /* |
194 | * The removed flag needs to be updated atomically with the pointer. | |
195 | * The dummy flag does not require to be updated atomically with the | |
196 | * pointer, but it is added as a pointer low bit flag to save space. | |
197 | */ | |
d37166c6 | 198 | #define REMOVED_FLAG (1UL << 0) |
f5596c94 MD |
199 | #define DUMMY_FLAG (1UL << 1) |
200 | #define FLAGS_MASK ((1UL << 2) - 1) | |
d37166c6 | 201 | |
df44348d | 202 | struct ht_items_count { |
3171717f | 203 | unsigned long add, remove; |
df44348d MD |
204 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
205 | ||
1475579c MD |
206 | struct rcu_level { |
207 | struct rcu_head head; | |
208 | struct _cds_lfht_node nodes[0]; | |
209 | }; | |
210 | ||
395270b6 | 211 | struct rcu_table { |
4105056a | 212 | unsigned long size; /* always a power of 2, shared (RCU) */ |
f9830efd | 213 | unsigned long resize_target; |
11519af6 | 214 | int resize_initiated; |
4105056a | 215 | struct rcu_level *tbl[MAX_TABLE_ORDER]; |
395270b6 MD |
216 | }; |
217 | ||
14044b37 | 218 | struct cds_lfht { |
4105056a | 219 | struct rcu_table t; |
14044b37 MD |
220 | cds_lfht_hash_fct hash_fct; |
221 | cds_lfht_compare_fct compare_fct; | |
732ad076 | 222 | unsigned long hash_seed; |
b8af5011 | 223 | int flags; |
464a1ec9 | 224 | pthread_mutex_t resize_mutex; /* resize mutex: add/del mutex */ |
33c7c748 | 225 | unsigned int in_progress_resize, in_progress_destroy; |
14044b37 | 226 | void (*cds_lfht_call_rcu)(struct rcu_head *head, |
abc490a1 | 227 | void (*func)(struct rcu_head *head)); |
1475579c | 228 | void (*cds_lfht_synchronize_rcu)(void); |
01dbfa62 MD |
229 | void (*cds_lfht_rcu_read_lock)(void); |
230 | void (*cds_lfht_rcu_read_unlock)(void); | |
df44348d MD |
231 | unsigned long count; /* global approximate item count */ |
232 | struct ht_items_count *percpu_count; /* per-cpu item count */ | |
2ed95849 MD |
233 | }; |
234 | ||
abc490a1 MD |
235 | struct rcu_resize_work { |
236 | struct rcu_head head; | |
14044b37 | 237 | struct cds_lfht *ht; |
abc490a1 | 238 | }; |
2ed95849 | 239 | |
abc490a1 MD |
240 | /* |
241 | * Algorithm to reverse bits in a word by lookup table, extended to | |
242 | * 64-bit words. | |
f9830efd | 243 | * Source: |
abc490a1 | 244 | * http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable |
f9830efd | 245 | * Originally from Public Domain. |
abc490a1 MD |
246 | */ |
247 | ||
248 | static const uint8_t BitReverseTable256[256] = | |
2ed95849 | 249 | { |
abc490a1 MD |
250 | #define R2(n) (n), (n) + 2*64, (n) + 1*64, (n) + 3*64 |
251 | #define R4(n) R2(n), R2((n) + 2*16), R2((n) + 1*16), R2((n) + 3*16) | |
252 | #define R6(n) R4(n), R4((n) + 2*4 ), R4((n) + 1*4 ), R4((n) + 3*4 ) | |
253 | R6(0), R6(2), R6(1), R6(3) | |
254 | }; | |
255 | #undef R2 | |
256 | #undef R4 | |
257 | #undef R6 | |
2ed95849 | 258 | |
abc490a1 MD |
259 | static |
260 | uint8_t bit_reverse_u8(uint8_t v) | |
261 | { | |
262 | return BitReverseTable256[v]; | |
263 | } | |
ab7d5fc6 | 264 | |
abc490a1 MD |
265 | static __attribute__((unused)) |
266 | uint32_t bit_reverse_u32(uint32_t v) | |
267 | { | |
268 | return ((uint32_t) bit_reverse_u8(v) << 24) | | |
269 | ((uint32_t) bit_reverse_u8(v >> 8) << 16) | | |
270 | ((uint32_t) bit_reverse_u8(v >> 16) << 8) | | |
271 | ((uint32_t) bit_reverse_u8(v >> 24)); | |
2ed95849 MD |
272 | } |
273 | ||
abc490a1 MD |
274 | static __attribute__((unused)) |
275 | uint64_t bit_reverse_u64(uint64_t v) | |
2ed95849 | 276 | { |
abc490a1 MD |
277 | return ((uint64_t) bit_reverse_u8(v) << 56) | |
278 | ((uint64_t) bit_reverse_u8(v >> 8) << 48) | | |
279 | ((uint64_t) bit_reverse_u8(v >> 16) << 40) | | |
280 | ((uint64_t) bit_reverse_u8(v >> 24) << 32) | | |
281 | ((uint64_t) bit_reverse_u8(v >> 32) << 24) | | |
282 | ((uint64_t) bit_reverse_u8(v >> 40) << 16) | | |
283 | ((uint64_t) bit_reverse_u8(v >> 48) << 8) | | |
284 | ((uint64_t) bit_reverse_u8(v >> 56)); | |
285 | } | |
286 | ||
287 | static | |
288 | unsigned long bit_reverse_ulong(unsigned long v) | |
289 | { | |
290 | #if (CAA_BITS_PER_LONG == 32) | |
291 | return bit_reverse_u32(v); | |
292 | #else | |
293 | return bit_reverse_u64(v); | |
294 | #endif | |
295 | } | |
296 | ||
f9830efd | 297 | /* |
24365af7 MD |
298 | * fls: returns the position of the most significant bit. |
299 | * Returns 0 if no bit is set, else returns the position of the most | |
300 | * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit). | |
f9830efd | 301 | */ |
24365af7 MD |
302 | #if defined(__i386) || defined(__x86_64) |
303 | static inline | |
304 | unsigned int fls_u32(uint32_t x) | |
f9830efd | 305 | { |
24365af7 MD |
306 | int r; |
307 | ||
308 | asm("bsrl %1,%0\n\t" | |
309 | "jnz 1f\n\t" | |
310 | "movl $-1,%0\n\t" | |
311 | "1:\n\t" | |
312 | : "=r" (r) : "rm" (x)); | |
313 | return r + 1; | |
314 | } | |
315 | #define HAS_FLS_U32 | |
316 | #endif | |
317 | ||
318 | #if defined(__x86_64) | |
319 | static inline | |
320 | unsigned int fls_u64(uint64_t x) | |
321 | { | |
322 | long r; | |
323 | ||
324 | asm("bsrq %1,%0\n\t" | |
325 | "jnz 1f\n\t" | |
326 | "movq $-1,%0\n\t" | |
327 | "1:\n\t" | |
328 | : "=r" (r) : "rm" (x)); | |
329 | return r + 1; | |
330 | } | |
331 | #define HAS_FLS_U64 | |
332 | #endif | |
333 | ||
334 | #ifndef HAS_FLS_U64 | |
335 | static __attribute__((unused)) | |
336 | unsigned int fls_u64(uint64_t x) | |
337 | { | |
338 | unsigned int r = 64; | |
339 | ||
340 | if (!x) | |
341 | return 0; | |
342 | ||
343 | if (!(x & 0xFFFFFFFF00000000ULL)) { | |
344 | x <<= 32; | |
345 | r -= 32; | |
346 | } | |
347 | if (!(x & 0xFFFF000000000000ULL)) { | |
348 | x <<= 16; | |
349 | r -= 16; | |
350 | } | |
351 | if (!(x & 0xFF00000000000000ULL)) { | |
352 | x <<= 8; | |
353 | r -= 8; | |
354 | } | |
355 | if (!(x & 0xF000000000000000ULL)) { | |
356 | x <<= 4; | |
357 | r -= 4; | |
358 | } | |
359 | if (!(x & 0xC000000000000000ULL)) { | |
360 | x <<= 2; | |
361 | r -= 2; | |
362 | } | |
363 | if (!(x & 0x8000000000000000ULL)) { | |
364 | x <<= 1; | |
365 | r -= 1; | |
366 | } | |
367 | return r; | |
368 | } | |
369 | #endif | |
370 | ||
371 | #ifndef HAS_FLS_U32 | |
372 | static __attribute__((unused)) | |
373 | unsigned int fls_u32(uint32_t x) | |
374 | { | |
375 | unsigned int r = 32; | |
f9830efd | 376 | |
24365af7 MD |
377 | if (!x) |
378 | return 0; | |
379 | if (!(x & 0xFFFF0000U)) { | |
380 | x <<= 16; | |
381 | r -= 16; | |
382 | } | |
383 | if (!(x & 0xFF000000U)) { | |
384 | x <<= 8; | |
385 | r -= 8; | |
386 | } | |
387 | if (!(x & 0xF0000000U)) { | |
388 | x <<= 4; | |
389 | r -= 4; | |
390 | } | |
391 | if (!(x & 0xC0000000U)) { | |
392 | x <<= 2; | |
393 | r -= 2; | |
394 | } | |
395 | if (!(x & 0x80000000U)) { | |
396 | x <<= 1; | |
397 | r -= 1; | |
398 | } | |
399 | return r; | |
400 | } | |
401 | #endif | |
402 | ||
403 | unsigned int fls_ulong(unsigned long x) | |
f9830efd | 404 | { |
24365af7 MD |
405 | #if (CAA_BITS_PER_lONG == 32) |
406 | return fls_u32(x); | |
407 | #else | |
408 | return fls_u64(x); | |
409 | #endif | |
410 | } | |
f9830efd | 411 | |
24365af7 MD |
412 | int get_count_order_u32(uint32_t x) |
413 | { | |
414 | int order; | |
415 | ||
416 | order = fls_u32(x) - 1; | |
417 | if (x & (x - 1)) | |
418 | order++; | |
419 | return order; | |
420 | } | |
421 | ||
422 | int get_count_order_ulong(unsigned long x) | |
423 | { | |
424 | int order; | |
425 | ||
426 | order = fls_ulong(x) - 1; | |
427 | if (x & (x - 1)) | |
428 | order++; | |
429 | return order; | |
f9830efd MD |
430 | } |
431 | ||
98808fb1 MD |
432 | #ifdef POISON_FREE |
433 | #define poison_free(ptr) \ | |
434 | do { \ | |
435 | memset(ptr, 0x42, sizeof(*(ptr))); \ | |
436 | free(ptr); \ | |
437 | } while (0) | |
438 | #else | |
439 | #define poison_free(ptr) free(ptr) | |
440 | #endif | |
441 | ||
f9830efd | 442 | static |
4105056a | 443 | void cds_lfht_resize_lazy(struct cds_lfht *ht, unsigned long size, int growth); |
f9830efd | 444 | |
df44348d MD |
445 | /* |
446 | * If the sched_getcpu() and sysconf(_SC_NPROCESSORS_CONF) calls are | |
447 | * available, then we support hash table item accounting. | |
448 | * In the unfortunate event the number of CPUs reported would be | |
449 | * inaccurate, we use modulo arithmetic on the number of CPUs we got. | |
450 | */ | |
df44348d MD |
451 | #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) |
452 | ||
f8994aee | 453 | static |
4105056a | 454 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, |
f8994aee MD |
455 | unsigned long count); |
456 | ||
df44348d MD |
457 | static long nr_cpus_mask = -1; |
458 | ||
459 | static | |
460 | struct ht_items_count *alloc_per_cpu_items_count(void) | |
461 | { | |
462 | struct ht_items_count *count; | |
463 | ||
464 | switch (nr_cpus_mask) { | |
465 | case -2: | |
466 | return NULL; | |
467 | case -1: | |
468 | { | |
469 | long maxcpus; | |
470 | ||
471 | maxcpus = sysconf(_SC_NPROCESSORS_CONF); | |
472 | if (maxcpus <= 0) { | |
473 | nr_cpus_mask = -2; | |
474 | return NULL; | |
475 | } | |
476 | /* | |
477 | * round up number of CPUs to next power of two, so we | |
478 | * can use & for modulo. | |
479 | */ | |
480 | maxcpus = 1UL << get_count_order_ulong(maxcpus); | |
481 | nr_cpus_mask = maxcpus - 1; | |
482 | } | |
483 | /* Fall-through */ | |
484 | default: | |
485 | return calloc(nr_cpus_mask + 1, sizeof(*count)); | |
486 | } | |
487 | } | |
488 | ||
489 | static | |
490 | void free_per_cpu_items_count(struct ht_items_count *count) | |
491 | { | |
98808fb1 | 492 | poison_free(count); |
df44348d MD |
493 | } |
494 | ||
495 | static | |
496 | int ht_get_cpu(void) | |
497 | { | |
498 | int cpu; | |
499 | ||
500 | assert(nr_cpus_mask >= 0); | |
501 | cpu = sched_getcpu(); | |
502 | if (unlikely(cpu < 0)) | |
503 | return cpu; | |
504 | else | |
505 | return cpu & nr_cpus_mask; | |
506 | } | |
507 | ||
508 | static | |
4105056a | 509 | void ht_count_add(struct cds_lfht *ht, unsigned long size) |
df44348d | 510 | { |
3171717f | 511 | unsigned long percpu_count; |
df44348d MD |
512 | int cpu; |
513 | ||
514 | if (unlikely(!ht->percpu_count)) | |
3171717f | 515 | return; |
df44348d MD |
516 | cpu = ht_get_cpu(); |
517 | if (unlikely(cpu < 0)) | |
3171717f MD |
518 | return; |
519 | percpu_count = uatomic_add_return(&ht->percpu_count[cpu].add, 1); | |
df44348d MD |
520 | if (unlikely(!(percpu_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) { |
521 | unsigned long count; | |
522 | ||
523 | dbg_printf("add percpu %lu\n", percpu_count); | |
524 | count = uatomic_add_return(&ht->count, | |
525 | 1UL << COUNT_COMMIT_ORDER); | |
526 | /* If power of 2 */ | |
527 | if (!(count & (count - 1))) { | |
4105056a | 528 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) < size) |
f8994aee MD |
529 | return; |
530 | dbg_printf("add set global %lu\n", count); | |
4105056a | 531 | cds_lfht_resize_lazy_count(ht, size, |
6ea6bc67 | 532 | count >> (CHAIN_LEN_TARGET - 1)); |
df44348d MD |
533 | } |
534 | } | |
535 | } | |
536 | ||
537 | static | |
4105056a | 538 | void ht_count_remove(struct cds_lfht *ht, unsigned long size) |
df44348d MD |
539 | { |
540 | unsigned long percpu_count; | |
3171717f | 541 | int cpu; |
df44348d | 542 | |
3171717f MD |
543 | if (unlikely(!ht->percpu_count)) |
544 | return; | |
545 | cpu = ht_get_cpu(); | |
546 | if (unlikely(cpu < 0)) | |
547 | return; | |
548 | percpu_count = uatomic_add_return(&ht->percpu_count[cpu].remove, -1); | |
df44348d MD |
549 | if (unlikely(!(percpu_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) { |
550 | unsigned long count; | |
551 | ||
552 | dbg_printf("remove percpu %lu\n", percpu_count); | |
553 | count = uatomic_add_return(&ht->count, | |
3171717f | 554 | -(1UL << COUNT_COMMIT_ORDER)); |
df44348d MD |
555 | /* If power of 2 */ |
556 | if (!(count & (count - 1))) { | |
4105056a | 557 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) >= size) |
f8994aee MD |
558 | return; |
559 | dbg_printf("remove set global %lu\n", count); | |
4105056a | 560 | cds_lfht_resize_lazy_count(ht, size, |
6ea6bc67 | 561 | count >> (CHAIN_LEN_TARGET - 1)); |
df44348d MD |
562 | } |
563 | } | |
564 | } | |
565 | ||
566 | #else /* #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */ | |
567 | ||
568 | static const long nr_cpus_mask = -1; | |
569 | ||
570 | static | |
571 | struct ht_items_count *alloc_per_cpu_items_count(void) | |
572 | { | |
573 | return NULL; | |
574 | } | |
575 | ||
576 | static | |
577 | void free_per_cpu_items_count(struct ht_items_count *count) | |
578 | { | |
579 | } | |
580 | ||
581 | static | |
4105056a | 582 | void ht_count_add(struct cds_lfht *ht, unsigned long size) |
df44348d MD |
583 | { |
584 | } | |
585 | ||
586 | static | |
4105056a | 587 | void ht_count_remove(struct cds_lfht *ht, unsigned long size) |
df44348d MD |
588 | { |
589 | } | |
590 | ||
591 | #endif /* #else #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */ | |
592 | ||
593 | ||
f9830efd | 594 | static |
4105056a | 595 | void check_resize(struct cds_lfht *ht, unsigned long size, uint32_t chain_len) |
f9830efd | 596 | { |
f8994aee MD |
597 | unsigned long count; |
598 | ||
b8af5011 MD |
599 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) |
600 | return; | |
f8994aee MD |
601 | count = uatomic_read(&ht->count); |
602 | /* | |
603 | * Use bucket-local length for small table expand and for | |
604 | * environments lacking per-cpu data support. | |
605 | */ | |
606 | if (count >= (1UL << COUNT_COMMIT_ORDER)) | |
607 | return; | |
24365af7 | 608 | if (chain_len > 100) |
f0c29ed7 | 609 | dbg_printf("WARNING: large chain length: %u.\n", |
24365af7 | 610 | chain_len); |
3390d470 | 611 | if (chain_len >= CHAIN_LEN_RESIZE_THRESHOLD) |
4105056a | 612 | cds_lfht_resize_lazy(ht, size, |
01370f0b | 613 | get_count_order_u32(chain_len - (CHAIN_LEN_TARGET - 1))); |
f9830efd MD |
614 | } |
615 | ||
abc490a1 | 616 | static |
14044b37 | 617 | struct cds_lfht_node *clear_flag(struct cds_lfht_node *node) |
abc490a1 | 618 | { |
14044b37 | 619 | return (struct cds_lfht_node *) (((unsigned long) node) & ~FLAGS_MASK); |
abc490a1 MD |
620 | } |
621 | ||
622 | static | |
14044b37 | 623 | int is_removed(struct cds_lfht_node *node) |
abc490a1 | 624 | { |
d37166c6 | 625 | return ((unsigned long) node) & REMOVED_FLAG; |
abc490a1 MD |
626 | } |
627 | ||
628 | static | |
14044b37 | 629 | struct cds_lfht_node *flag_removed(struct cds_lfht_node *node) |
abc490a1 | 630 | { |
14044b37 | 631 | return (struct cds_lfht_node *) (((unsigned long) node) | REMOVED_FLAG); |
abc490a1 MD |
632 | } |
633 | ||
f5596c94 | 634 | static |
14044b37 | 635 | int is_dummy(struct cds_lfht_node *node) |
f5596c94 MD |
636 | { |
637 | return ((unsigned long) node) & DUMMY_FLAG; | |
638 | } | |
639 | ||
640 | static | |
14044b37 | 641 | struct cds_lfht_node *flag_dummy(struct cds_lfht_node *node) |
f5596c94 | 642 | { |
14044b37 | 643 | return (struct cds_lfht_node *) (((unsigned long) node) | DUMMY_FLAG); |
f5596c94 MD |
644 | } |
645 | ||
abc490a1 | 646 | static |
f9830efd | 647 | unsigned long _uatomic_max(unsigned long *ptr, unsigned long v) |
abc490a1 MD |
648 | { |
649 | unsigned long old1, old2; | |
650 | ||
651 | old1 = uatomic_read(ptr); | |
652 | do { | |
653 | old2 = old1; | |
654 | if (old2 >= v) | |
f9830efd | 655 | return old2; |
abc490a1 | 656 | } while ((old1 = uatomic_cmpxchg(ptr, old2, v)) != old2); |
f9830efd | 657 | return v; |
abc490a1 MD |
658 | } |
659 | ||
1475579c MD |
660 | static |
661 | void cds_lfht_free_level(struct rcu_head *head) | |
662 | { | |
663 | struct rcu_level *l = | |
664 | caa_container_of(head, struct rcu_level, head); | |
98808fb1 | 665 | poison_free(l); |
1475579c MD |
666 | } |
667 | ||
273399de MD |
668 | /* |
669 | * Remove all logically deleted nodes from a bucket up to a certain node key. | |
670 | */ | |
671 | static | |
14044b37 | 672 | void _cds_lfht_gc_bucket(struct cds_lfht_node *dummy, struct cds_lfht_node *node) |
273399de | 673 | { |
14044b37 | 674 | struct cds_lfht_node *iter_prev, *iter, *next, *new_next; |
273399de | 675 | |
c90201ac MD |
676 | assert(!is_dummy(dummy)); |
677 | assert(!is_removed(dummy)); | |
678 | assert(!is_dummy(node)); | |
679 | assert(!is_removed(node)); | |
273399de MD |
680 | for (;;) { |
681 | iter_prev = dummy; | |
682 | /* We can always skip the dummy node initially */ | |
cc4fcb10 MD |
683 | iter = rcu_dereference(iter_prev->p.next); |
684 | assert(iter_prev->p.reverse_hash <= node->p.reverse_hash); | |
bd4db153 MD |
685 | /* |
686 | * We should never be called with dummy (start of chain) | |
687 | * and logically removed node (end of path compression | |
688 | * marker) being the actual same node. This would be a | |
689 | * bug in the algorithm implementation. | |
690 | */ | |
691 | assert(dummy != node); | |
273399de | 692 | for (;;) { |
a2974903 | 693 | if (unlikely(!clear_flag(iter))) |
479c8a32 | 694 | return; |
76412f24 | 695 | if (likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash)) |
273399de | 696 | return; |
cc4fcb10 | 697 | next = rcu_dereference(clear_flag(iter)->p.next); |
76412f24 | 698 | if (likely(is_removed(next))) |
273399de | 699 | break; |
b453eae1 | 700 | iter_prev = clear_flag(iter); |
273399de MD |
701 | iter = next; |
702 | } | |
703 | assert(!is_removed(iter)); | |
f5596c94 MD |
704 | if (is_dummy(iter)) |
705 | new_next = flag_dummy(clear_flag(next)); | |
706 | else | |
707 | new_next = clear_flag(next); | |
708 | (void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next); | |
273399de MD |
709 | } |
710 | } | |
711 | ||
abc490a1 | 712 | static |
4105056a MD |
713 | struct cds_lfht_node *_cds_lfht_add(struct cds_lfht *ht, |
714 | unsigned long size, | |
715 | struct cds_lfht_node *node, | |
716 | int unique, int dummy) | |
abc490a1 | 717 | { |
14044b37 | 718 | struct cds_lfht_node *iter_prev, *iter, *next, *new_node, *new_next, |
f5596c94 | 719 | *dummy_node; |
14044b37 | 720 | struct _cds_lfht_node *lookup; |
24365af7 | 721 | unsigned long hash, index, order; |
abc490a1 | 722 | |
c90201ac MD |
723 | assert(!is_dummy(node)); |
724 | assert(!is_removed(node)); | |
4105056a | 725 | if (!size) { |
f5596c94 MD |
726 | assert(dummy); |
727 | node->p.next = flag_dummy(NULL); | |
18117871 MD |
728 | return node; /* Initial first add (head) */ |
729 | } | |
cc4fcb10 | 730 | hash = bit_reverse_ulong(node->p.reverse_hash); |
abc490a1 | 731 | for (;;) { |
f9830efd | 732 | uint32_t chain_len = 0; |
abc490a1 | 733 | |
11519af6 MD |
734 | /* |
735 | * iter_prev points to the non-removed node prior to the | |
736 | * insert location. | |
11519af6 | 737 | */ |
4105056a | 738 | index = hash & (size - 1); |
24365af7 | 739 | order = get_count_order_ulong(index + 1); |
4105056a | 740 | lookup = &ht->t.tbl[order]->nodes[index & ((!order ? 0 : (1UL << (order - 1))) - 1)]; |
14044b37 | 741 | iter_prev = (struct cds_lfht_node *) lookup; |
11519af6 | 742 | /* We can always skip the dummy node initially */ |
cc4fcb10 MD |
743 | iter = rcu_dereference(iter_prev->p.next); |
744 | assert(iter_prev->p.reverse_hash <= node->p.reverse_hash); | |
abc490a1 | 745 | for (;;) { |
c90201ac | 746 | /* TODO: check if removed */ |
a2974903 | 747 | if (unlikely(!clear_flag(iter))) |
273399de | 748 | goto insert; |
c90201ac | 749 | /* TODO: check if removed */ |
76412f24 | 750 | if (likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash)) |
273399de | 751 | goto insert; |
cc4fcb10 | 752 | next = rcu_dereference(clear_flag(iter)->p.next); |
76412f24 | 753 | if (unlikely(is_removed(next))) |
9dba85be | 754 | goto gc_node; |
e43f23f8 | 755 | if (unique |
1b81fe1a | 756 | && !is_dummy(next) |
e43f23f8 MD |
757 | && !ht->compare_fct(node->key, node->key_len, |
758 | clear_flag(iter)->key, | |
759 | clear_flag(iter)->key_len)) | |
18117871 | 760 | return clear_flag(iter); |
11519af6 | 761 | /* Only account for identical reverse hash once */ |
24365af7 MD |
762 | if (iter_prev->p.reverse_hash != clear_flag(iter)->p.reverse_hash |
763 | && !is_dummy(next)) | |
4105056a | 764 | check_resize(ht, size, ++chain_len); |
11519af6 | 765 | iter_prev = clear_flag(iter); |
273399de | 766 | iter = next; |
abc490a1 | 767 | } |
273399de | 768 | insert: |
7ec59d3b | 769 | assert(node != clear_flag(iter)); |
11519af6 | 770 | assert(!is_removed(iter_prev)); |
c90201ac | 771 | assert(!is_removed(iter)); |
f000907d | 772 | assert(iter_prev != node); |
f5596c94 | 773 | if (!dummy) |
1b81fe1a | 774 | node->p.next = clear_flag(iter); |
f5596c94 | 775 | else |
1b81fe1a | 776 | node->p.next = flag_dummy(clear_flag(iter)); |
f5596c94 MD |
777 | if (is_dummy(iter)) |
778 | new_node = flag_dummy(node); | |
779 | else | |
780 | new_node = node; | |
cc4fcb10 | 781 | if (uatomic_cmpxchg(&iter_prev->p.next, iter, |
f5596c94 | 782 | new_node) != iter) |
273399de | 783 | continue; /* retry */ |
11519af6 | 784 | else |
273399de | 785 | goto gc_end; |
9dba85be MD |
786 | gc_node: |
787 | assert(!is_removed(iter)); | |
f5596c94 MD |
788 | if (is_dummy(iter)) |
789 | new_next = flag_dummy(clear_flag(next)); | |
790 | else | |
791 | new_next = clear_flag(next); | |
792 | (void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next); | |
273399de | 793 | /* retry */ |
464a1ec9 | 794 | } |
273399de MD |
795 | gc_end: |
796 | /* Garbage collect logically removed nodes in the bucket */ | |
4105056a | 797 | index = hash & (size - 1); |
24365af7 | 798 | order = get_count_order_ulong(index + 1); |
4105056a | 799 | lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1)) - 1))]; |
14044b37 MD |
800 | dummy_node = (struct cds_lfht_node *) lookup; |
801 | _cds_lfht_gc_bucket(dummy_node, node); | |
18117871 | 802 | return node; |
abc490a1 | 803 | } |
464a1ec9 | 804 | |
abc490a1 | 805 | static |
4105056a MD |
806 | int _cds_lfht_remove(struct cds_lfht *ht, unsigned long size, |
807 | struct cds_lfht_node *node, | |
808 | int dummy_removal) | |
abc490a1 | 809 | { |
14044b37 MD |
810 | struct cds_lfht_node *dummy, *next, *old; |
811 | struct _cds_lfht_node *lookup; | |
abc490a1 | 812 | int flagged = 0; |
24365af7 | 813 | unsigned long hash, index, order; |
5e28c532 | 814 | |
7ec59d3b | 815 | /* logically delete the node */ |
c90201ac MD |
816 | assert(!is_dummy(node)); |
817 | assert(!is_removed(node)); | |
cc4fcb10 | 818 | old = rcu_dereference(node->p.next); |
7ec59d3b MD |
819 | do { |
820 | next = old; | |
76412f24 | 821 | if (unlikely(is_removed(next))) |
7ec59d3b | 822 | goto end; |
1475579c MD |
823 | if (dummy_removal) |
824 | assert(is_dummy(next)); | |
825 | else | |
826 | assert(!is_dummy(next)); | |
cc4fcb10 | 827 | old = uatomic_cmpxchg(&node->p.next, next, |
7ec59d3b MD |
828 | flag_removed(next)); |
829 | } while (old != next); | |
830 | ||
831 | /* We performed the (logical) deletion. */ | |
832 | flagged = 1; | |
833 | ||
834 | /* | |
835 | * Ensure that the node is not visible to readers anymore: lookup for | |
273399de MD |
836 | * the node, and remove it (along with any other logically removed node) |
837 | * if found. | |
11519af6 | 838 | */ |
cc4fcb10 | 839 | hash = bit_reverse_ulong(node->p.reverse_hash); |
4105056a MD |
840 | assert(size > 0); |
841 | index = hash & (size - 1); | |
24365af7 | 842 | order = get_count_order_ulong(index + 1); |
4105056a | 843 | lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1)) - 1))]; |
14044b37 MD |
844 | dummy = (struct cds_lfht_node *) lookup; |
845 | _cds_lfht_gc_bucket(dummy, node); | |
2ed95849 | 846 | end: |
11519af6 MD |
847 | /* |
848 | * Only the flagging action indicated that we (and no other) | |
849 | * removed the node from the hash. | |
850 | */ | |
7ec59d3b | 851 | if (flagged) { |
cc4fcb10 | 852 | assert(is_removed(rcu_dereference(node->p.next))); |
11519af6 | 853 | return 0; |
7ec59d3b | 854 | } else |
11519af6 | 855 | return -ENOENT; |
abc490a1 | 856 | } |
2ed95849 | 857 | |
4105056a MD |
858 | static |
859 | void init_table_hash(struct cds_lfht *ht, unsigned long i, | |
860 | unsigned long len) | |
861 | { | |
862 | unsigned long j; | |
863 | ||
864 | for (j = 0; j < len; j++) { | |
865 | struct cds_lfht_node *new_node = | |
866 | (struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j]; | |
867 | ||
868 | dbg_printf("init hash entry: i %lu j %lu hash %lu\n", | |
869 | i, j, !i ? 0 : (1UL << (i - 1)) + j); | |
870 | new_node->p.reverse_hash = | |
871 | bit_reverse_ulong(!i ? 0 : (1UL << (i - 1)) + j); | |
872 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
873 | break; | |
874 | } | |
875 | } | |
876 | ||
877 | static | |
878 | void init_table_link(struct cds_lfht *ht, unsigned long i, unsigned long len) | |
879 | { | |
880 | unsigned long j; | |
881 | ||
882 | ht->cds_lfht_rcu_read_lock(); | |
883 | for (j = 0; j < len; j++) { | |
884 | struct cds_lfht_node *new_node = | |
885 | (struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j]; | |
886 | ||
887 | dbg_printf("init link: i %lu j %lu hash %lu\n", | |
888 | i, j, !i ? 0 : (1UL << (i - 1)) + j); | |
889 | (void) _cds_lfht_add(ht, !i ? 0 : (1UL << (i - 1)), | |
890 | new_node, 0, 1); | |
891 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
892 | break; | |
893 | } | |
894 | ht->cds_lfht_rcu_read_unlock(); | |
895 | } | |
896 | ||
01dbfa62 MD |
897 | /* |
898 | * Holding RCU read lock to protect _cds_lfht_add against memory | |
899 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
900 | * problem). | |
901 | */ | |
abc490a1 | 902 | static |
4105056a | 903 | void init_table(struct cds_lfht *ht, |
24365af7 MD |
904 | unsigned long first_order, unsigned long len_order) |
905 | { | |
906 | unsigned long i, end_order; | |
907 | ||
f0c29ed7 | 908 | dbg_printf("init table: first_order %lu end_order %lu\n", |
24365af7 MD |
909 | first_order, first_order + len_order); |
910 | end_order = first_order + len_order; | |
24365af7 | 911 | for (i = first_order; i < end_order; i++) { |
4105056a | 912 | unsigned long len; |
24365af7 MD |
913 | |
914 | len = !i ? 1 : 1UL << (i - 1); | |
f0c29ed7 | 915 | dbg_printf("init order %lu len: %lu\n", i, len); |
4105056a | 916 | ht->t.tbl[i] = calloc(1, sizeof(struct rcu_level) |
1475579c | 917 | + (len * sizeof(struct _cds_lfht_node))); |
4105056a MD |
918 | |
919 | /* Set all dummy nodes reverse hash values for a level */ | |
920 | init_table_hash(ht, i, len); | |
921 | ||
922 | /* | |
923 | * Link all dummy nodes into the table. Concurrent | |
924 | * add/remove are helping us. | |
925 | */ | |
926 | init_table_link(ht, i, len); | |
927 | ||
928 | /* | |
929 | * Update table size (after init for now, because no | |
930 | * concurrent updater help (TODO)). | |
931 | */ | |
932 | cmm_smp_wmb(); /* populate data before RCU size */ | |
933 | CMM_STORE_SHARED(ht->t.size, !i ? 1 : (1UL << i)); | |
934 | dbg_printf("init new size: %lu\n", !i ? 1 : (1UL << i)); | |
935 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
936 | break; | |
937 | } | |
938 | } | |
939 | ||
940 | static | |
941 | void remove_table(struct cds_lfht *ht, unsigned long i, unsigned long len) | |
942 | { | |
943 | unsigned long j; | |
944 | ||
945 | ht->cds_lfht_rcu_read_lock(); | |
946 | for (j = 0; j < len; j++) { | |
947 | struct cds_lfht_node *fini_node = | |
948 | (struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j]; | |
949 | ||
950 | dbg_printf("remove entry: i %lu j %lu hash %lu\n", | |
951 | i, j, !i ? 0 : (1UL << (i - 1)) + j); | |
952 | fini_node->p.reverse_hash = | |
953 | bit_reverse_ulong(!i ? 0 : (1UL << (i - 1)) + j); | |
954 | (void) _cds_lfht_remove(ht, !i ? 0 : (1UL << (i - 1)), | |
955 | fini_node, 1); | |
33c7c748 MD |
956 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
957 | break; | |
abc490a1 | 958 | } |
4105056a | 959 | ht->cds_lfht_rcu_read_unlock(); |
2ed95849 MD |
960 | } |
961 | ||
01dbfa62 MD |
962 | /* |
963 | * Holding RCU read lock to protect _cds_lfht_remove against memory | |
964 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
965 | * problem). | |
966 | */ | |
1475579c | 967 | static |
4105056a | 968 | void fini_table(struct cds_lfht *ht, |
1475579c MD |
969 | unsigned long first_order, unsigned long len_order) |
970 | { | |
971 | long i, end_order; | |
972 | ||
973 | dbg_printf("fini table: first_order %lu end_order %lu\n", | |
974 | first_order, first_order + len_order); | |
975 | end_order = first_order + len_order; | |
976 | assert(first_order > 0); | |
4105056a | 977 | assert(ht->t.size == (1UL << (first_order - 1))); |
1475579c | 978 | for (i = end_order - 1; i >= first_order; i--) { |
4105056a | 979 | unsigned long len; |
1475579c MD |
980 | |
981 | len = !i ? 1 : 1UL << (i - 1); | |
982 | dbg_printf("fini order %lu len: %lu\n", i, len); | |
4105056a | 983 | |
21263e21 | 984 | /* |
4105056a MD |
985 | * Set "removed" flag in dummy nodes about to be removed. |
986 | * Unlink all now-logically-removed dummy node pointers. | |
987 | * Concurrent add/remove operation are helping us doing | |
988 | * the gc. | |
21263e21 | 989 | */ |
4105056a MD |
990 | remove_table(ht, i, len); |
991 | ||
992 | ht->cds_lfht_call_rcu(&ht->t.tbl[i]->head, cds_lfht_free_level); | |
993 | ||
994 | dbg_printf("fini new size: %lu\n", 1UL << i); | |
1475579c MD |
995 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
996 | break; | |
997 | } | |
1475579c MD |
998 | } |
999 | ||
14044b37 MD |
1000 | struct cds_lfht *cds_lfht_new(cds_lfht_hash_fct hash_fct, |
1001 | cds_lfht_compare_fct compare_fct, | |
1002 | unsigned long hash_seed, | |
1003 | unsigned long init_size, | |
b8af5011 | 1004 | int flags, |
14044b37 | 1005 | void (*cds_lfht_call_rcu)(struct rcu_head *head, |
1475579c | 1006 | void (*func)(struct rcu_head *head)), |
01dbfa62 MD |
1007 | void (*cds_lfht_synchronize_rcu)(void), |
1008 | void (*cds_lfht_rcu_read_lock)(void), | |
1009 | void (*cds_lfht_rcu_read_unlock)(void)) | |
abc490a1 | 1010 | { |
14044b37 | 1011 | struct cds_lfht *ht; |
24365af7 | 1012 | unsigned long order; |
abc490a1 | 1013 | |
8129be4e | 1014 | /* init_size must be power of two */ |
49619ea0 | 1015 | if (init_size && (init_size & (init_size - 1))) |
8129be4e | 1016 | return NULL; |
14044b37 | 1017 | ht = calloc(1, sizeof(struct cds_lfht)); |
abc490a1 | 1018 | ht->hash_fct = hash_fct; |
732ad076 MD |
1019 | ht->compare_fct = compare_fct; |
1020 | ht->hash_seed = hash_seed; | |
14044b37 | 1021 | ht->cds_lfht_call_rcu = cds_lfht_call_rcu; |
1475579c | 1022 | ht->cds_lfht_synchronize_rcu = cds_lfht_synchronize_rcu; |
01dbfa62 MD |
1023 | ht->cds_lfht_rcu_read_lock = cds_lfht_rcu_read_lock; |
1024 | ht->cds_lfht_rcu_read_unlock = cds_lfht_rcu_read_unlock; | |
df44348d | 1025 | ht->percpu_count = alloc_per_cpu_items_count(); |
abc490a1 MD |
1026 | /* this mutex should not nest in read-side C.S. */ |
1027 | pthread_mutex_init(&ht->resize_mutex, NULL); | |
cd95516d | 1028 | order = get_count_order_ulong(max(init_size, MIN_TABLE_SIZE)) + 1; |
b8af5011 | 1029 | ht->flags = flags; |
f000907d | 1030 | pthread_mutex_lock(&ht->resize_mutex); |
4105056a | 1031 | init_table(ht, 0, order); |
f000907d | 1032 | pthread_mutex_unlock(&ht->resize_mutex); |
abc490a1 MD |
1033 | return ht; |
1034 | } | |
1035 | ||
14044b37 | 1036 | struct cds_lfht_node *cds_lfht_lookup(struct cds_lfht *ht, void *key, size_t key_len) |
2ed95849 | 1037 | { |
14044b37 MD |
1038 | struct cds_lfht_node *node, *next; |
1039 | struct _cds_lfht_node *lookup; | |
4105056a | 1040 | unsigned long hash, reverse_hash, index, order, size; |
2ed95849 | 1041 | |
732ad076 | 1042 | hash = ht->hash_fct(key, key_len, ht->hash_seed); |
abc490a1 | 1043 | reverse_hash = bit_reverse_ulong(hash); |
464a1ec9 | 1044 | |
4105056a MD |
1045 | size = rcu_dereference(ht->t.size); |
1046 | index = hash & (size - 1); | |
24365af7 | 1047 | order = get_count_order_ulong(index + 1); |
4105056a | 1048 | lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1))) - 1)]; |
f0c29ed7 | 1049 | dbg_printf("lookup hash %lu index %lu order %lu aridx %lu\n", |
554c284e | 1050 | hash, index, order, index & (!order ? 0 : ((1UL << (order - 1)) - 1))); |
14044b37 | 1051 | node = (struct cds_lfht_node *) lookup; |
2ed95849 | 1052 | for (;;) { |
abc490a1 MD |
1053 | if (unlikely(!node)) |
1054 | break; | |
cc4fcb10 | 1055 | if (unlikely(node->p.reverse_hash > reverse_hash)) { |
abc490a1 MD |
1056 | node = NULL; |
1057 | break; | |
2ed95849 | 1058 | } |
1b81fe1a MD |
1059 | next = rcu_dereference(node->p.next); |
1060 | if (likely(!is_removed(next)) | |
1061 | && !is_dummy(next) | |
49c2e2d6 | 1062 | && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) { |
273399de | 1063 | break; |
2ed95849 | 1064 | } |
1b81fe1a | 1065 | node = clear_flag(next); |
2ed95849 | 1066 | } |
1b81fe1a | 1067 | assert(!node || !is_dummy(rcu_dereference(node->p.next))); |
abc490a1 MD |
1068 | return node; |
1069 | } | |
e0ba718a | 1070 | |
a481e5ff MD |
1071 | struct cds_lfht_node *cds_lfht_next(struct cds_lfht *ht, |
1072 | struct cds_lfht_node *node) | |
1073 | { | |
1074 | struct cds_lfht_node *next; | |
1075 | unsigned long reverse_hash; | |
1076 | void *key; | |
1077 | size_t key_len; | |
1078 | ||
1079 | reverse_hash = node->p.reverse_hash; | |
1080 | key = node->key; | |
1081 | key_len = node->key_len; | |
1082 | next = rcu_dereference(node->p.next); | |
1083 | node = clear_flag(next); | |
1084 | ||
1085 | for (;;) { | |
1086 | if (unlikely(!node)) | |
1087 | break; | |
1088 | if (unlikely(node->p.reverse_hash > reverse_hash)) { | |
1089 | node = NULL; | |
1090 | break; | |
1091 | } | |
1092 | next = rcu_dereference(node->p.next); | |
1093 | if (likely(!is_removed(next)) | |
1094 | && !is_dummy(next) | |
1095 | && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) { | |
1096 | break; | |
1097 | } | |
1098 | node = clear_flag(next); | |
1099 | } | |
1100 | assert(!node || !is_dummy(rcu_dereference(node->p.next))); | |
1101 | return node; | |
1102 | } | |
1103 | ||
14044b37 | 1104 | void cds_lfht_add(struct cds_lfht *ht, struct cds_lfht_node *node) |
abc490a1 | 1105 | { |
4105056a | 1106 | unsigned long hash, size; |
ab7d5fc6 | 1107 | |
49c2e2d6 | 1108 | hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed); |
cc4fcb10 | 1109 | node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash); |
2ed95849 | 1110 | |
4105056a MD |
1111 | size = rcu_dereference(ht->t.size); |
1112 | (void) _cds_lfht_add(ht, size, node, 0, 0); | |
1113 | ht_count_add(ht, size); | |
3eca1b8c MD |
1114 | } |
1115 | ||
14044b37 MD |
1116 | struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, |
1117 | struct cds_lfht_node *node) | |
3eca1b8c | 1118 | { |
4105056a | 1119 | unsigned long hash, size; |
df44348d | 1120 | struct cds_lfht_node *ret; |
3eca1b8c | 1121 | |
49c2e2d6 | 1122 | hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed); |
cc4fcb10 | 1123 | node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash); |
3eca1b8c | 1124 | |
4105056a MD |
1125 | size = rcu_dereference(ht->t.size); |
1126 | ret = _cds_lfht_add(ht, size, node, 1, 0); | |
df44348d | 1127 | if (ret != node) |
4105056a | 1128 | ht_count_add(ht, size); |
df44348d | 1129 | return ret; |
2ed95849 MD |
1130 | } |
1131 | ||
14044b37 | 1132 | int cds_lfht_remove(struct cds_lfht *ht, struct cds_lfht_node *node) |
2ed95849 | 1133 | { |
4105056a | 1134 | unsigned long size; |
df44348d | 1135 | int ret; |
abc490a1 | 1136 | |
4105056a MD |
1137 | size = rcu_dereference(ht->t.size); |
1138 | ret = _cds_lfht_remove(ht, size, node, 0); | |
df44348d | 1139 | if (!ret) |
4105056a | 1140 | ht_count_remove(ht, size); |
df44348d | 1141 | return ret; |
2ed95849 | 1142 | } |
ab7d5fc6 | 1143 | |
abc490a1 | 1144 | static |
14044b37 | 1145 | int cds_lfht_delete_dummy(struct cds_lfht *ht) |
674f7a69 | 1146 | { |
14044b37 MD |
1147 | struct cds_lfht_node *node; |
1148 | struct _cds_lfht_node *lookup; | |
4105056a | 1149 | unsigned long order, i, size; |
674f7a69 | 1150 | |
abc490a1 | 1151 | /* Check that the table is empty */ |
4105056a | 1152 | lookup = &ht->t.tbl[0]->nodes[0]; |
14044b37 | 1153 | node = (struct cds_lfht_node *) lookup; |
abc490a1 | 1154 | do { |
1b81fe1a MD |
1155 | node = clear_flag(node)->p.next; |
1156 | if (!is_dummy(node)) | |
abc490a1 | 1157 | return -EPERM; |
273399de | 1158 | assert(!is_removed(node)); |
a2974903 | 1159 | } while (clear_flag(node)); |
4105056a MD |
1160 | /* |
1161 | * size accessed without rcu_dereference because hash table is | |
1162 | * being destroyed. | |
1163 | */ | |
1164 | size = ht->t.size; | |
abc490a1 | 1165 | /* Internal sanity check: all nodes left should be dummy */ |
4105056a | 1166 | for (order = 0; order < get_count_order_ulong(size) + 1; order++) { |
24365af7 MD |
1167 | unsigned long len; |
1168 | ||
1169 | len = !order ? 1 : 1UL << (order - 1); | |
1170 | for (i = 0; i < len; i++) { | |
f0c29ed7 | 1171 | dbg_printf("delete order %lu i %lu hash %lu\n", |
24365af7 | 1172 | order, i, |
4105056a MD |
1173 | bit_reverse_ulong(ht->t.tbl[order]->nodes[i].reverse_hash)); |
1174 | assert(is_dummy(ht->t.tbl[order]->nodes[i].next)); | |
24365af7 | 1175 | } |
4105056a | 1176 | poison_free(ht->t.tbl[order]); |
674f7a69 | 1177 | } |
abc490a1 | 1178 | return 0; |
674f7a69 MD |
1179 | } |
1180 | ||
1181 | /* | |
1182 | * Should only be called when no more concurrent readers nor writers can | |
1183 | * possibly access the table. | |
1184 | */ | |
14044b37 | 1185 | int cds_lfht_destroy(struct cds_lfht *ht) |
674f7a69 | 1186 | { |
5e28c532 MD |
1187 | int ret; |
1188 | ||
848d4088 | 1189 | /* Wait for in-flight resize operations to complete */ |
33c7c748 | 1190 | CMM_STORE_SHARED(ht->in_progress_destroy, 1); |
848d4088 MD |
1191 | while (uatomic_read(&ht->in_progress_resize)) |
1192 | poll(NULL, 0, 100); /* wait for 100ms */ | |
14044b37 | 1193 | ret = cds_lfht_delete_dummy(ht); |
abc490a1 MD |
1194 | if (ret) |
1195 | return ret; | |
df44348d | 1196 | free_per_cpu_items_count(ht->percpu_count); |
98808fb1 | 1197 | poison_free(ht); |
5e28c532 | 1198 | return ret; |
674f7a69 MD |
1199 | } |
1200 | ||
14044b37 | 1201 | void cds_lfht_count_nodes(struct cds_lfht *ht, |
273399de MD |
1202 | unsigned long *count, |
1203 | unsigned long *removed) | |
1204 | { | |
14044b37 MD |
1205 | struct cds_lfht_node *node, *next; |
1206 | struct _cds_lfht_node *lookup; | |
24365af7 | 1207 | unsigned long nr_dummy = 0; |
273399de MD |
1208 | |
1209 | *count = 0; | |
1210 | *removed = 0; | |
1211 | ||
24365af7 | 1212 | /* Count non-dummy nodes in the table */ |
4105056a | 1213 | lookup = &ht->t.tbl[0]->nodes[0]; |
14044b37 | 1214 | node = (struct cds_lfht_node *) lookup; |
273399de | 1215 | do { |
cc4fcb10 | 1216 | next = rcu_dereference(node->p.next); |
273399de | 1217 | if (is_removed(next)) { |
1b81fe1a | 1218 | assert(!is_dummy(next)); |
273399de | 1219 | (*removed)++; |
1b81fe1a | 1220 | } else if (!is_dummy(next)) |
273399de | 1221 | (*count)++; |
24365af7 MD |
1222 | else |
1223 | (nr_dummy)++; | |
273399de MD |
1224 | node = clear_flag(next); |
1225 | } while (node); | |
f0c29ed7 | 1226 | dbg_printf("number of dummy nodes: %lu\n", nr_dummy); |
273399de MD |
1227 | } |
1228 | ||
1475579c | 1229 | /* called with resize mutex held */ |
abc490a1 | 1230 | static |
4105056a | 1231 | void _do_cds_lfht_grow(struct cds_lfht *ht, |
1475579c | 1232 | unsigned long old_size, unsigned long new_size) |
abc490a1 | 1233 | { |
1475579c | 1234 | unsigned long old_order, new_order; |
1475579c MD |
1235 | |
1236 | old_order = get_count_order_ulong(old_size) + 1; | |
1237 | new_order = get_count_order_ulong(new_size) + 1; | |
1238 | printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", | |
1239 | old_size, old_order, new_size, new_order); | |
1475579c | 1240 | assert(new_size > old_size); |
4105056a | 1241 | init_table(ht, old_order, new_order - old_order); |
abc490a1 MD |
1242 | } |
1243 | ||
1244 | /* called with resize mutex held */ | |
1245 | static | |
4105056a | 1246 | void _do_cds_lfht_shrink(struct cds_lfht *ht, |
1475579c | 1247 | unsigned long old_size, unsigned long new_size) |
464a1ec9 | 1248 | { |
1475579c | 1249 | unsigned long old_order, new_order; |
464a1ec9 | 1250 | |
cd95516d | 1251 | new_size = max(new_size, MIN_TABLE_SIZE); |
24365af7 | 1252 | old_order = get_count_order_ulong(old_size) + 1; |
24365af7 | 1253 | new_order = get_count_order_ulong(new_size) + 1; |
df44348d | 1254 | printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", |
df03fab8 | 1255 | old_size, old_order, new_size, new_order); |
1475579c | 1256 | assert(new_size < old_size); |
1475579c | 1257 | |
4105056a MD |
1258 | cmm_smp_wmb(); /* populate data before RCU size */ |
1259 | CMM_STORE_SHARED(ht->t.size, new_size); | |
1475579c MD |
1260 | |
1261 | /* | |
c90201ac | 1262 | * We need to wait for all add operations to reach Q.S. (and |
1475579c | 1263 | * thus use the new table for lookups) before we can start |
c90201ac MD |
1264 | * releasing the old dummy nodes. Otherwise their lookup will |
1265 | * return a logically removed node as insert position. | |
1475579c MD |
1266 | */ |
1267 | ht->cds_lfht_synchronize_rcu(); | |
1268 | ||
4105056a MD |
1269 | /* Remove and unlink all dummy nodes to remove. */ |
1270 | fini_table(ht, new_order, old_order - new_order); | |
464a1ec9 MD |
1271 | } |
1272 | ||
1475579c MD |
1273 | |
1274 | /* called with resize mutex held */ | |
1275 | static | |
1276 | void _do_cds_lfht_resize(struct cds_lfht *ht) | |
1277 | { | |
1278 | unsigned long new_size, old_size; | |
4105056a MD |
1279 | |
1280 | /* | |
1281 | * Resize table, re-do if the target size has changed under us. | |
1282 | */ | |
1283 | do { | |
1284 | ht->t.resize_initiated = 1; | |
1285 | old_size = ht->t.size; | |
1286 | new_size = CMM_LOAD_SHARED(ht->t.resize_target); | |
1287 | if (old_size < new_size) | |
1288 | _do_cds_lfht_grow(ht, old_size, new_size); | |
1289 | else if (old_size > new_size) | |
1290 | _do_cds_lfht_shrink(ht, old_size, new_size); | |
1291 | ht->t.resize_initiated = 0; | |
1292 | /* write resize_initiated before read resize_target */ | |
1293 | cmm_smp_mb(); | |
1294 | } while (new_size != CMM_LOAD_SHARED(ht->t.resize_target)); | |
1475579c MD |
1295 | } |
1296 | ||
abc490a1 | 1297 | static |
4105056a | 1298 | unsigned long resize_target_update(struct cds_lfht *ht, unsigned long size, |
f9830efd | 1299 | int growth_order) |
464a1ec9 | 1300 | { |
4105056a MD |
1301 | return _uatomic_max(&ht->t.resize_target, |
1302 | size << growth_order); | |
464a1ec9 MD |
1303 | } |
1304 | ||
1475579c | 1305 | static |
4105056a | 1306 | void resize_target_update_count(struct cds_lfht *ht, |
b8af5011 | 1307 | unsigned long count) |
1475579c | 1308 | { |
cd95516d | 1309 | count = max(count, MIN_TABLE_SIZE); |
4105056a | 1310 | uatomic_set(&ht->t.resize_target, count); |
1475579c MD |
1311 | } |
1312 | ||
1313 | void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size) | |
464a1ec9 | 1314 | { |
4105056a MD |
1315 | resize_target_update_count(ht, new_size); |
1316 | CMM_STORE_SHARED(ht->t.resize_initiated, 1); | |
1475579c MD |
1317 | pthread_mutex_lock(&ht->resize_mutex); |
1318 | _do_cds_lfht_resize(ht); | |
1319 | pthread_mutex_unlock(&ht->resize_mutex); | |
abc490a1 | 1320 | } |
464a1ec9 | 1321 | |
abc490a1 MD |
1322 | static |
1323 | void do_resize_cb(struct rcu_head *head) | |
1324 | { | |
1325 | struct rcu_resize_work *work = | |
1326 | caa_container_of(head, struct rcu_resize_work, head); | |
14044b37 | 1327 | struct cds_lfht *ht = work->ht; |
abc490a1 MD |
1328 | |
1329 | pthread_mutex_lock(&ht->resize_mutex); | |
14044b37 | 1330 | _do_cds_lfht_resize(ht); |
abc490a1 | 1331 | pthread_mutex_unlock(&ht->resize_mutex); |
98808fb1 | 1332 | poison_free(work); |
848d4088 MD |
1333 | cmm_smp_mb(); /* finish resize before decrement */ |
1334 | uatomic_dec(&ht->in_progress_resize); | |
464a1ec9 MD |
1335 | } |
1336 | ||
abc490a1 | 1337 | static |
4105056a | 1338 | void cds_lfht_resize_lazy(struct cds_lfht *ht, unsigned long size, int growth) |
ab7d5fc6 | 1339 | { |
abc490a1 | 1340 | struct rcu_resize_work *work; |
f9830efd | 1341 | unsigned long target_size; |
abc490a1 | 1342 | |
4105056a MD |
1343 | target_size = resize_target_update(ht, size, growth); |
1344 | /* Store resize_target before read resize_initiated */ | |
1345 | cmm_smp_mb(); | |
1346 | if (!CMM_LOAD_SHARED(ht->t.resize_initiated) && size < target_size) { | |
848d4088 MD |
1347 | uatomic_inc(&ht->in_progress_resize); |
1348 | cmm_smp_mb(); /* increment resize count before calling it */ | |
f9830efd MD |
1349 | work = malloc(sizeof(*work)); |
1350 | work->ht = ht; | |
14044b37 | 1351 | ht->cds_lfht_call_rcu(&work->head, do_resize_cb); |
4105056a | 1352 | CMM_STORE_SHARED(ht->t.resize_initiated, 1); |
f9830efd | 1353 | } |
ab7d5fc6 | 1354 | } |
3171717f | 1355 | |
f8994aee MD |
1356 | #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) |
1357 | ||
3171717f | 1358 | static |
4105056a | 1359 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, |
3171717f MD |
1360 | unsigned long count) |
1361 | { | |
1362 | struct rcu_resize_work *work; | |
3171717f | 1363 | |
b8af5011 MD |
1364 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) |
1365 | return; | |
4105056a MD |
1366 | resize_target_update_count(ht, count); |
1367 | /* Store resize_target before read resize_initiated */ | |
1368 | cmm_smp_mb(); | |
1369 | if (!CMM_LOAD_SHARED(ht->t.resize_initiated)) { | |
3171717f MD |
1370 | uatomic_inc(&ht->in_progress_resize); |
1371 | cmm_smp_mb(); /* increment resize count before calling it */ | |
1372 | work = malloc(sizeof(*work)); | |
1373 | work->ht = ht; | |
1374 | ht->cds_lfht_call_rcu(&work->head, do_resize_cb); | |
4105056a | 1375 | CMM_STORE_SHARED(ht->t.resize_initiated, 1); |
3171717f MD |
1376 | } |
1377 | } | |
f8994aee MD |
1378 | |
1379 | #endif |