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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; |
5f511391 MD |
224 | /* |
225 | * We need to put the work threads offline (QSBR) when taking this | |
226 | * mutex, because we use synchronize_rcu within this mutex critical | |
227 | * section, which waits on read-side critical sections, and could | |
228 | * therefore cause grace-period deadlock if we hold off RCU G.P. | |
229 | * completion. | |
230 | */ | |
464a1ec9 | 231 | pthread_mutex_t resize_mutex; /* resize mutex: add/del mutex */ |
33c7c748 | 232 | unsigned int in_progress_resize, in_progress_destroy; |
14044b37 | 233 | void (*cds_lfht_call_rcu)(struct rcu_head *head, |
abc490a1 | 234 | void (*func)(struct rcu_head *head)); |
1475579c | 235 | void (*cds_lfht_synchronize_rcu)(void); |
01dbfa62 MD |
236 | void (*cds_lfht_rcu_read_lock)(void); |
237 | void (*cds_lfht_rcu_read_unlock)(void); | |
5f511391 MD |
238 | void (*cds_lfht_rcu_thread_offline)(void); |
239 | void (*cds_lfht_rcu_thread_online)(void); | |
df44348d MD |
240 | unsigned long count; /* global approximate item count */ |
241 | struct ht_items_count *percpu_count; /* per-cpu item count */ | |
2ed95849 MD |
242 | }; |
243 | ||
abc490a1 MD |
244 | struct rcu_resize_work { |
245 | struct rcu_head head; | |
14044b37 | 246 | struct cds_lfht *ht; |
abc490a1 | 247 | }; |
2ed95849 | 248 | |
abc490a1 MD |
249 | /* |
250 | * Algorithm to reverse bits in a word by lookup table, extended to | |
251 | * 64-bit words. | |
f9830efd | 252 | * Source: |
abc490a1 | 253 | * http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable |
f9830efd | 254 | * Originally from Public Domain. |
abc490a1 MD |
255 | */ |
256 | ||
257 | static const uint8_t BitReverseTable256[256] = | |
2ed95849 | 258 | { |
abc490a1 MD |
259 | #define R2(n) (n), (n) + 2*64, (n) + 1*64, (n) + 3*64 |
260 | #define R4(n) R2(n), R2((n) + 2*16), R2((n) + 1*16), R2((n) + 3*16) | |
261 | #define R6(n) R4(n), R4((n) + 2*4 ), R4((n) + 1*4 ), R4((n) + 3*4 ) | |
262 | R6(0), R6(2), R6(1), R6(3) | |
263 | }; | |
264 | #undef R2 | |
265 | #undef R4 | |
266 | #undef R6 | |
2ed95849 | 267 | |
abc490a1 MD |
268 | static |
269 | uint8_t bit_reverse_u8(uint8_t v) | |
270 | { | |
271 | return BitReverseTable256[v]; | |
272 | } | |
ab7d5fc6 | 273 | |
abc490a1 MD |
274 | static __attribute__((unused)) |
275 | uint32_t bit_reverse_u32(uint32_t v) | |
276 | { | |
277 | return ((uint32_t) bit_reverse_u8(v) << 24) | | |
278 | ((uint32_t) bit_reverse_u8(v >> 8) << 16) | | |
279 | ((uint32_t) bit_reverse_u8(v >> 16) << 8) | | |
280 | ((uint32_t) bit_reverse_u8(v >> 24)); | |
2ed95849 MD |
281 | } |
282 | ||
abc490a1 MD |
283 | static __attribute__((unused)) |
284 | uint64_t bit_reverse_u64(uint64_t v) | |
2ed95849 | 285 | { |
abc490a1 MD |
286 | return ((uint64_t) bit_reverse_u8(v) << 56) | |
287 | ((uint64_t) bit_reverse_u8(v >> 8) << 48) | | |
288 | ((uint64_t) bit_reverse_u8(v >> 16) << 40) | | |
289 | ((uint64_t) bit_reverse_u8(v >> 24) << 32) | | |
290 | ((uint64_t) bit_reverse_u8(v >> 32) << 24) | | |
291 | ((uint64_t) bit_reverse_u8(v >> 40) << 16) | | |
292 | ((uint64_t) bit_reverse_u8(v >> 48) << 8) | | |
293 | ((uint64_t) bit_reverse_u8(v >> 56)); | |
294 | } | |
295 | ||
296 | static | |
297 | unsigned long bit_reverse_ulong(unsigned long v) | |
298 | { | |
299 | #if (CAA_BITS_PER_LONG == 32) | |
300 | return bit_reverse_u32(v); | |
301 | #else | |
302 | return bit_reverse_u64(v); | |
303 | #endif | |
304 | } | |
305 | ||
f9830efd | 306 | /* |
24365af7 MD |
307 | * fls: returns the position of the most significant bit. |
308 | * Returns 0 if no bit is set, else returns the position of the most | |
309 | * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit). | |
f9830efd | 310 | */ |
24365af7 MD |
311 | #if defined(__i386) || defined(__x86_64) |
312 | static inline | |
313 | unsigned int fls_u32(uint32_t x) | |
f9830efd | 314 | { |
24365af7 MD |
315 | int r; |
316 | ||
317 | asm("bsrl %1,%0\n\t" | |
318 | "jnz 1f\n\t" | |
319 | "movl $-1,%0\n\t" | |
320 | "1:\n\t" | |
321 | : "=r" (r) : "rm" (x)); | |
322 | return r + 1; | |
323 | } | |
324 | #define HAS_FLS_U32 | |
325 | #endif | |
326 | ||
327 | #if defined(__x86_64) | |
328 | static inline | |
329 | unsigned int fls_u64(uint64_t x) | |
330 | { | |
331 | long r; | |
332 | ||
333 | asm("bsrq %1,%0\n\t" | |
334 | "jnz 1f\n\t" | |
335 | "movq $-1,%0\n\t" | |
336 | "1:\n\t" | |
337 | : "=r" (r) : "rm" (x)); | |
338 | return r + 1; | |
339 | } | |
340 | #define HAS_FLS_U64 | |
341 | #endif | |
342 | ||
343 | #ifndef HAS_FLS_U64 | |
344 | static __attribute__((unused)) | |
345 | unsigned int fls_u64(uint64_t x) | |
346 | { | |
347 | unsigned int r = 64; | |
348 | ||
349 | if (!x) | |
350 | return 0; | |
351 | ||
352 | if (!(x & 0xFFFFFFFF00000000ULL)) { | |
353 | x <<= 32; | |
354 | r -= 32; | |
355 | } | |
356 | if (!(x & 0xFFFF000000000000ULL)) { | |
357 | x <<= 16; | |
358 | r -= 16; | |
359 | } | |
360 | if (!(x & 0xFF00000000000000ULL)) { | |
361 | x <<= 8; | |
362 | r -= 8; | |
363 | } | |
364 | if (!(x & 0xF000000000000000ULL)) { | |
365 | x <<= 4; | |
366 | r -= 4; | |
367 | } | |
368 | if (!(x & 0xC000000000000000ULL)) { | |
369 | x <<= 2; | |
370 | r -= 2; | |
371 | } | |
372 | if (!(x & 0x8000000000000000ULL)) { | |
373 | x <<= 1; | |
374 | r -= 1; | |
375 | } | |
376 | return r; | |
377 | } | |
378 | #endif | |
379 | ||
380 | #ifndef HAS_FLS_U32 | |
381 | static __attribute__((unused)) | |
382 | unsigned int fls_u32(uint32_t x) | |
383 | { | |
384 | unsigned int r = 32; | |
f9830efd | 385 | |
24365af7 MD |
386 | if (!x) |
387 | return 0; | |
388 | if (!(x & 0xFFFF0000U)) { | |
389 | x <<= 16; | |
390 | r -= 16; | |
391 | } | |
392 | if (!(x & 0xFF000000U)) { | |
393 | x <<= 8; | |
394 | r -= 8; | |
395 | } | |
396 | if (!(x & 0xF0000000U)) { | |
397 | x <<= 4; | |
398 | r -= 4; | |
399 | } | |
400 | if (!(x & 0xC0000000U)) { | |
401 | x <<= 2; | |
402 | r -= 2; | |
403 | } | |
404 | if (!(x & 0x80000000U)) { | |
405 | x <<= 1; | |
406 | r -= 1; | |
407 | } | |
408 | return r; | |
409 | } | |
410 | #endif | |
411 | ||
412 | unsigned int fls_ulong(unsigned long x) | |
f9830efd | 413 | { |
24365af7 MD |
414 | #if (CAA_BITS_PER_lONG == 32) |
415 | return fls_u32(x); | |
416 | #else | |
417 | return fls_u64(x); | |
418 | #endif | |
419 | } | |
f9830efd | 420 | |
24365af7 MD |
421 | int get_count_order_u32(uint32_t x) |
422 | { | |
423 | int order; | |
424 | ||
425 | order = fls_u32(x) - 1; | |
426 | if (x & (x - 1)) | |
427 | order++; | |
428 | return order; | |
429 | } | |
430 | ||
431 | int get_count_order_ulong(unsigned long x) | |
432 | { | |
433 | int order; | |
434 | ||
435 | order = fls_ulong(x) - 1; | |
436 | if (x & (x - 1)) | |
437 | order++; | |
438 | return order; | |
f9830efd MD |
439 | } |
440 | ||
98808fb1 MD |
441 | #ifdef POISON_FREE |
442 | #define poison_free(ptr) \ | |
443 | do { \ | |
444 | memset(ptr, 0x42, sizeof(*(ptr))); \ | |
445 | free(ptr); \ | |
446 | } while (0) | |
447 | #else | |
448 | #define poison_free(ptr) free(ptr) | |
449 | #endif | |
450 | ||
f9830efd | 451 | static |
4105056a | 452 | void cds_lfht_resize_lazy(struct cds_lfht *ht, unsigned long size, int growth); |
f9830efd | 453 | |
df44348d MD |
454 | /* |
455 | * If the sched_getcpu() and sysconf(_SC_NPROCESSORS_CONF) calls are | |
456 | * available, then we support hash table item accounting. | |
457 | * In the unfortunate event the number of CPUs reported would be | |
458 | * inaccurate, we use modulo arithmetic on the number of CPUs we got. | |
459 | */ | |
df44348d MD |
460 | #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) |
461 | ||
f8994aee | 462 | static |
4105056a | 463 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, |
f8994aee MD |
464 | unsigned long count); |
465 | ||
df44348d MD |
466 | static long nr_cpus_mask = -1; |
467 | ||
468 | static | |
469 | struct ht_items_count *alloc_per_cpu_items_count(void) | |
470 | { | |
471 | struct ht_items_count *count; | |
472 | ||
473 | switch (nr_cpus_mask) { | |
474 | case -2: | |
475 | return NULL; | |
476 | case -1: | |
477 | { | |
478 | long maxcpus; | |
479 | ||
480 | maxcpus = sysconf(_SC_NPROCESSORS_CONF); | |
481 | if (maxcpus <= 0) { | |
482 | nr_cpus_mask = -2; | |
483 | return NULL; | |
484 | } | |
485 | /* | |
486 | * round up number of CPUs to next power of two, so we | |
487 | * can use & for modulo. | |
488 | */ | |
489 | maxcpus = 1UL << get_count_order_ulong(maxcpus); | |
490 | nr_cpus_mask = maxcpus - 1; | |
491 | } | |
492 | /* Fall-through */ | |
493 | default: | |
494 | return calloc(nr_cpus_mask + 1, sizeof(*count)); | |
495 | } | |
496 | } | |
497 | ||
498 | static | |
499 | void free_per_cpu_items_count(struct ht_items_count *count) | |
500 | { | |
98808fb1 | 501 | poison_free(count); |
df44348d MD |
502 | } |
503 | ||
504 | static | |
505 | int ht_get_cpu(void) | |
506 | { | |
507 | int cpu; | |
508 | ||
509 | assert(nr_cpus_mask >= 0); | |
510 | cpu = sched_getcpu(); | |
511 | if (unlikely(cpu < 0)) | |
512 | return cpu; | |
513 | else | |
514 | return cpu & nr_cpus_mask; | |
515 | } | |
516 | ||
517 | static | |
4105056a | 518 | void ht_count_add(struct cds_lfht *ht, unsigned long size) |
df44348d | 519 | { |
3171717f | 520 | unsigned long percpu_count; |
df44348d MD |
521 | int cpu; |
522 | ||
523 | if (unlikely(!ht->percpu_count)) | |
3171717f | 524 | return; |
df44348d MD |
525 | cpu = ht_get_cpu(); |
526 | if (unlikely(cpu < 0)) | |
3171717f MD |
527 | return; |
528 | percpu_count = uatomic_add_return(&ht->percpu_count[cpu].add, 1); | |
df44348d MD |
529 | if (unlikely(!(percpu_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) { |
530 | unsigned long count; | |
531 | ||
532 | dbg_printf("add percpu %lu\n", percpu_count); | |
533 | count = uatomic_add_return(&ht->count, | |
534 | 1UL << COUNT_COMMIT_ORDER); | |
535 | /* If power of 2 */ | |
536 | if (!(count & (count - 1))) { | |
4105056a | 537 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) < size) |
f8994aee MD |
538 | return; |
539 | dbg_printf("add set global %lu\n", count); | |
4105056a | 540 | cds_lfht_resize_lazy_count(ht, size, |
6ea6bc67 | 541 | count >> (CHAIN_LEN_TARGET - 1)); |
df44348d MD |
542 | } |
543 | } | |
544 | } | |
545 | ||
546 | static | |
4105056a | 547 | void ht_count_remove(struct cds_lfht *ht, unsigned long size) |
df44348d MD |
548 | { |
549 | unsigned long percpu_count; | |
3171717f | 550 | int cpu; |
df44348d | 551 | |
3171717f MD |
552 | if (unlikely(!ht->percpu_count)) |
553 | return; | |
554 | cpu = ht_get_cpu(); | |
555 | if (unlikely(cpu < 0)) | |
556 | return; | |
557 | percpu_count = uatomic_add_return(&ht->percpu_count[cpu].remove, -1); | |
df44348d MD |
558 | if (unlikely(!(percpu_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) { |
559 | unsigned long count; | |
560 | ||
561 | dbg_printf("remove percpu %lu\n", percpu_count); | |
562 | count = uatomic_add_return(&ht->count, | |
3171717f | 563 | -(1UL << COUNT_COMMIT_ORDER)); |
df44348d MD |
564 | /* If power of 2 */ |
565 | if (!(count & (count - 1))) { | |
4105056a | 566 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) >= size) |
f8994aee MD |
567 | return; |
568 | dbg_printf("remove set global %lu\n", count); | |
4105056a | 569 | cds_lfht_resize_lazy_count(ht, size, |
6ea6bc67 | 570 | count >> (CHAIN_LEN_TARGET - 1)); |
df44348d MD |
571 | } |
572 | } | |
573 | } | |
574 | ||
575 | #else /* #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */ | |
576 | ||
577 | static const long nr_cpus_mask = -1; | |
578 | ||
579 | static | |
580 | struct ht_items_count *alloc_per_cpu_items_count(void) | |
581 | { | |
582 | return NULL; | |
583 | } | |
584 | ||
585 | static | |
586 | void free_per_cpu_items_count(struct ht_items_count *count) | |
587 | { | |
588 | } | |
589 | ||
590 | static | |
4105056a | 591 | void ht_count_add(struct cds_lfht *ht, unsigned long size) |
df44348d MD |
592 | { |
593 | } | |
594 | ||
595 | static | |
4105056a | 596 | void ht_count_remove(struct cds_lfht *ht, unsigned long size) |
df44348d MD |
597 | { |
598 | } | |
599 | ||
600 | #endif /* #else #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */ | |
601 | ||
602 | ||
f9830efd | 603 | static |
4105056a | 604 | void check_resize(struct cds_lfht *ht, unsigned long size, uint32_t chain_len) |
f9830efd | 605 | { |
f8994aee MD |
606 | unsigned long count; |
607 | ||
b8af5011 MD |
608 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) |
609 | return; | |
f8994aee MD |
610 | count = uatomic_read(&ht->count); |
611 | /* | |
612 | * Use bucket-local length for small table expand and for | |
613 | * environments lacking per-cpu data support. | |
614 | */ | |
615 | if (count >= (1UL << COUNT_COMMIT_ORDER)) | |
616 | return; | |
24365af7 | 617 | if (chain_len > 100) |
f0c29ed7 | 618 | dbg_printf("WARNING: large chain length: %u.\n", |
24365af7 | 619 | chain_len); |
3390d470 | 620 | if (chain_len >= CHAIN_LEN_RESIZE_THRESHOLD) |
4105056a | 621 | cds_lfht_resize_lazy(ht, size, |
01370f0b | 622 | get_count_order_u32(chain_len - (CHAIN_LEN_TARGET - 1))); |
f9830efd MD |
623 | } |
624 | ||
abc490a1 | 625 | static |
14044b37 | 626 | struct cds_lfht_node *clear_flag(struct cds_lfht_node *node) |
abc490a1 | 627 | { |
14044b37 | 628 | return (struct cds_lfht_node *) (((unsigned long) node) & ~FLAGS_MASK); |
abc490a1 MD |
629 | } |
630 | ||
631 | static | |
14044b37 | 632 | int is_removed(struct cds_lfht_node *node) |
abc490a1 | 633 | { |
d37166c6 | 634 | return ((unsigned long) node) & REMOVED_FLAG; |
abc490a1 MD |
635 | } |
636 | ||
637 | static | |
14044b37 | 638 | struct cds_lfht_node *flag_removed(struct cds_lfht_node *node) |
abc490a1 | 639 | { |
14044b37 | 640 | return (struct cds_lfht_node *) (((unsigned long) node) | REMOVED_FLAG); |
abc490a1 MD |
641 | } |
642 | ||
f5596c94 | 643 | static |
14044b37 | 644 | int is_dummy(struct cds_lfht_node *node) |
f5596c94 MD |
645 | { |
646 | return ((unsigned long) node) & DUMMY_FLAG; | |
647 | } | |
648 | ||
649 | static | |
14044b37 | 650 | struct cds_lfht_node *flag_dummy(struct cds_lfht_node *node) |
f5596c94 | 651 | { |
14044b37 | 652 | return (struct cds_lfht_node *) (((unsigned long) node) | DUMMY_FLAG); |
f5596c94 MD |
653 | } |
654 | ||
abc490a1 | 655 | static |
f9830efd | 656 | unsigned long _uatomic_max(unsigned long *ptr, unsigned long v) |
abc490a1 MD |
657 | { |
658 | unsigned long old1, old2; | |
659 | ||
660 | old1 = uatomic_read(ptr); | |
661 | do { | |
662 | old2 = old1; | |
663 | if (old2 >= v) | |
f9830efd | 664 | return old2; |
abc490a1 | 665 | } while ((old1 = uatomic_cmpxchg(ptr, old2, v)) != old2); |
f9830efd | 666 | return v; |
abc490a1 MD |
667 | } |
668 | ||
1475579c MD |
669 | static |
670 | void cds_lfht_free_level(struct rcu_head *head) | |
671 | { | |
672 | struct rcu_level *l = | |
673 | caa_container_of(head, struct rcu_level, head); | |
98808fb1 | 674 | poison_free(l); |
1475579c MD |
675 | } |
676 | ||
273399de MD |
677 | /* |
678 | * Remove all logically deleted nodes from a bucket up to a certain node key. | |
679 | */ | |
680 | static | |
14044b37 | 681 | void _cds_lfht_gc_bucket(struct cds_lfht_node *dummy, struct cds_lfht_node *node) |
273399de | 682 | { |
14044b37 | 683 | struct cds_lfht_node *iter_prev, *iter, *next, *new_next; |
273399de | 684 | |
c90201ac MD |
685 | assert(!is_dummy(dummy)); |
686 | assert(!is_removed(dummy)); | |
687 | assert(!is_dummy(node)); | |
688 | assert(!is_removed(node)); | |
273399de MD |
689 | for (;;) { |
690 | iter_prev = dummy; | |
691 | /* We can always skip the dummy node initially */ | |
cc4fcb10 MD |
692 | iter = rcu_dereference(iter_prev->p.next); |
693 | assert(iter_prev->p.reverse_hash <= node->p.reverse_hash); | |
bd4db153 MD |
694 | /* |
695 | * We should never be called with dummy (start of chain) | |
696 | * and logically removed node (end of path compression | |
697 | * marker) being the actual same node. This would be a | |
698 | * bug in the algorithm implementation. | |
699 | */ | |
700 | assert(dummy != node); | |
273399de | 701 | for (;;) { |
a2974903 | 702 | if (unlikely(!clear_flag(iter))) |
479c8a32 | 703 | return; |
76412f24 | 704 | if (likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash)) |
273399de | 705 | return; |
cc4fcb10 | 706 | next = rcu_dereference(clear_flag(iter)->p.next); |
76412f24 | 707 | if (likely(is_removed(next))) |
273399de | 708 | break; |
b453eae1 | 709 | iter_prev = clear_flag(iter); |
273399de MD |
710 | iter = next; |
711 | } | |
712 | assert(!is_removed(iter)); | |
f5596c94 MD |
713 | if (is_dummy(iter)) |
714 | new_next = flag_dummy(clear_flag(next)); | |
715 | else | |
716 | new_next = clear_flag(next); | |
717 | (void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next); | |
273399de MD |
718 | } |
719 | } | |
720 | ||
abc490a1 | 721 | static |
4105056a MD |
722 | struct cds_lfht_node *_cds_lfht_add(struct cds_lfht *ht, |
723 | unsigned long size, | |
724 | struct cds_lfht_node *node, | |
725 | int unique, int dummy) | |
abc490a1 | 726 | { |
14044b37 | 727 | struct cds_lfht_node *iter_prev, *iter, *next, *new_node, *new_next, |
f5596c94 | 728 | *dummy_node; |
14044b37 | 729 | struct _cds_lfht_node *lookup; |
24365af7 | 730 | unsigned long hash, index, order; |
abc490a1 | 731 | |
c90201ac MD |
732 | assert(!is_dummy(node)); |
733 | assert(!is_removed(node)); | |
4105056a | 734 | if (!size) { |
f5596c94 MD |
735 | assert(dummy); |
736 | node->p.next = flag_dummy(NULL); | |
18117871 MD |
737 | return node; /* Initial first add (head) */ |
738 | } | |
cc4fcb10 | 739 | hash = bit_reverse_ulong(node->p.reverse_hash); |
abc490a1 | 740 | for (;;) { |
f9830efd | 741 | uint32_t chain_len = 0; |
abc490a1 | 742 | |
11519af6 MD |
743 | /* |
744 | * iter_prev points to the non-removed node prior to the | |
745 | * insert location. | |
11519af6 | 746 | */ |
4105056a | 747 | index = hash & (size - 1); |
24365af7 | 748 | order = get_count_order_ulong(index + 1); |
4105056a | 749 | lookup = &ht->t.tbl[order]->nodes[index & ((!order ? 0 : (1UL << (order - 1))) - 1)]; |
14044b37 | 750 | iter_prev = (struct cds_lfht_node *) lookup; |
11519af6 | 751 | /* We can always skip the dummy node initially */ |
cc4fcb10 MD |
752 | iter = rcu_dereference(iter_prev->p.next); |
753 | assert(iter_prev->p.reverse_hash <= node->p.reverse_hash); | |
abc490a1 | 754 | for (;;) { |
a2974903 | 755 | if (unlikely(!clear_flag(iter))) |
273399de | 756 | goto insert; |
76412f24 | 757 | if (likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash)) |
273399de | 758 | goto insert; |
cc4fcb10 | 759 | next = rcu_dereference(clear_flag(iter)->p.next); |
76412f24 | 760 | if (unlikely(is_removed(next))) |
9dba85be | 761 | goto gc_node; |
e43f23f8 | 762 | if (unique |
1b81fe1a | 763 | && !is_dummy(next) |
e43f23f8 MD |
764 | && !ht->compare_fct(node->key, node->key_len, |
765 | clear_flag(iter)->key, | |
766 | clear_flag(iter)->key_len)) | |
18117871 | 767 | return clear_flag(iter); |
11519af6 | 768 | /* Only account for identical reverse hash once */ |
24365af7 MD |
769 | if (iter_prev->p.reverse_hash != clear_flag(iter)->p.reverse_hash |
770 | && !is_dummy(next)) | |
4105056a | 771 | check_resize(ht, size, ++chain_len); |
11519af6 | 772 | iter_prev = clear_flag(iter); |
273399de | 773 | iter = next; |
abc490a1 | 774 | } |
273399de | 775 | insert: |
7ec59d3b | 776 | assert(node != clear_flag(iter)); |
11519af6 | 777 | assert(!is_removed(iter_prev)); |
c90201ac | 778 | assert(!is_removed(iter)); |
f000907d | 779 | assert(iter_prev != node); |
f5596c94 | 780 | if (!dummy) |
1b81fe1a | 781 | node->p.next = clear_flag(iter); |
f5596c94 | 782 | else |
1b81fe1a | 783 | node->p.next = flag_dummy(clear_flag(iter)); |
f5596c94 MD |
784 | if (is_dummy(iter)) |
785 | new_node = flag_dummy(node); | |
786 | else | |
787 | new_node = node; | |
cc4fcb10 | 788 | if (uatomic_cmpxchg(&iter_prev->p.next, iter, |
f5596c94 | 789 | new_node) != iter) |
273399de | 790 | continue; /* retry */ |
11519af6 | 791 | else |
273399de | 792 | goto gc_end; |
9dba85be MD |
793 | gc_node: |
794 | assert(!is_removed(iter)); | |
f5596c94 MD |
795 | if (is_dummy(iter)) |
796 | new_next = flag_dummy(clear_flag(next)); | |
797 | else | |
798 | new_next = clear_flag(next); | |
799 | (void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next); | |
273399de | 800 | /* retry */ |
464a1ec9 | 801 | } |
273399de MD |
802 | gc_end: |
803 | /* Garbage collect logically removed nodes in the bucket */ | |
4105056a | 804 | index = hash & (size - 1); |
24365af7 | 805 | order = get_count_order_ulong(index + 1); |
4105056a | 806 | lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1)) - 1))]; |
14044b37 MD |
807 | dummy_node = (struct cds_lfht_node *) lookup; |
808 | _cds_lfht_gc_bucket(dummy_node, node); | |
18117871 | 809 | return node; |
abc490a1 | 810 | } |
464a1ec9 | 811 | |
abc490a1 | 812 | static |
4105056a MD |
813 | int _cds_lfht_remove(struct cds_lfht *ht, unsigned long size, |
814 | struct cds_lfht_node *node, | |
815 | int dummy_removal) | |
abc490a1 | 816 | { |
14044b37 MD |
817 | struct cds_lfht_node *dummy, *next, *old; |
818 | struct _cds_lfht_node *lookup; | |
abc490a1 | 819 | int flagged = 0; |
24365af7 | 820 | unsigned long hash, index, order; |
5e28c532 | 821 | |
7ec59d3b | 822 | /* logically delete the node */ |
c90201ac MD |
823 | assert(!is_dummy(node)); |
824 | assert(!is_removed(node)); | |
cc4fcb10 | 825 | old = rcu_dereference(node->p.next); |
7ec59d3b MD |
826 | do { |
827 | next = old; | |
76412f24 | 828 | if (unlikely(is_removed(next))) |
7ec59d3b | 829 | goto end; |
1475579c MD |
830 | if (dummy_removal) |
831 | assert(is_dummy(next)); | |
832 | else | |
833 | assert(!is_dummy(next)); | |
cc4fcb10 | 834 | old = uatomic_cmpxchg(&node->p.next, next, |
7ec59d3b MD |
835 | flag_removed(next)); |
836 | } while (old != next); | |
837 | ||
838 | /* We performed the (logical) deletion. */ | |
839 | flagged = 1; | |
840 | ||
841 | /* | |
842 | * Ensure that the node is not visible to readers anymore: lookup for | |
273399de MD |
843 | * the node, and remove it (along with any other logically removed node) |
844 | * if found. | |
11519af6 | 845 | */ |
cc4fcb10 | 846 | hash = bit_reverse_ulong(node->p.reverse_hash); |
4105056a MD |
847 | assert(size > 0); |
848 | index = hash & (size - 1); | |
24365af7 | 849 | order = get_count_order_ulong(index + 1); |
4105056a | 850 | lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1)) - 1))]; |
14044b37 MD |
851 | dummy = (struct cds_lfht_node *) lookup; |
852 | _cds_lfht_gc_bucket(dummy, node); | |
2ed95849 | 853 | end: |
11519af6 MD |
854 | /* |
855 | * Only the flagging action indicated that we (and no other) | |
856 | * removed the node from the hash. | |
857 | */ | |
7ec59d3b | 858 | if (flagged) { |
cc4fcb10 | 859 | assert(is_removed(rcu_dereference(node->p.next))); |
11519af6 | 860 | return 0; |
7ec59d3b | 861 | } else |
11519af6 | 862 | return -ENOENT; |
abc490a1 | 863 | } |
2ed95849 | 864 | |
4105056a MD |
865 | static |
866 | void init_table_hash(struct cds_lfht *ht, unsigned long i, | |
867 | unsigned long len) | |
868 | { | |
869 | unsigned long j; | |
870 | ||
871 | for (j = 0; j < len; j++) { | |
872 | struct cds_lfht_node *new_node = | |
873 | (struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j]; | |
874 | ||
875 | dbg_printf("init hash entry: i %lu j %lu hash %lu\n", | |
876 | i, j, !i ? 0 : (1UL << (i - 1)) + j); | |
877 | new_node->p.reverse_hash = | |
878 | bit_reverse_ulong(!i ? 0 : (1UL << (i - 1)) + j); | |
879 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
880 | break; | |
881 | } | |
882 | } | |
883 | ||
884 | static | |
885 | void init_table_link(struct cds_lfht *ht, unsigned long i, unsigned long len) | |
886 | { | |
887 | unsigned long j; | |
888 | ||
5f511391 | 889 | ht->cds_lfht_rcu_thread_online(); |
4105056a MD |
890 | ht->cds_lfht_rcu_read_lock(); |
891 | for (j = 0; j < len; j++) { | |
892 | struct cds_lfht_node *new_node = | |
893 | (struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j]; | |
894 | ||
895 | dbg_printf("init link: i %lu j %lu hash %lu\n", | |
896 | i, j, !i ? 0 : (1UL << (i - 1)) + j); | |
897 | (void) _cds_lfht_add(ht, !i ? 0 : (1UL << (i - 1)), | |
898 | new_node, 0, 1); | |
899 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
900 | break; | |
901 | } | |
902 | ht->cds_lfht_rcu_read_unlock(); | |
5f511391 | 903 | ht->cds_lfht_rcu_thread_offline(); |
4105056a MD |
904 | } |
905 | ||
01dbfa62 MD |
906 | /* |
907 | * Holding RCU read lock to protect _cds_lfht_add against memory | |
908 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
909 | * problem). | |
910 | */ | |
abc490a1 | 911 | static |
4105056a | 912 | void init_table(struct cds_lfht *ht, |
24365af7 MD |
913 | unsigned long first_order, unsigned long len_order) |
914 | { | |
915 | unsigned long i, end_order; | |
916 | ||
f0c29ed7 | 917 | dbg_printf("init table: first_order %lu end_order %lu\n", |
24365af7 MD |
918 | first_order, first_order + len_order); |
919 | end_order = first_order + len_order; | |
24365af7 | 920 | for (i = first_order; i < end_order; i++) { |
4105056a | 921 | unsigned long len; |
24365af7 MD |
922 | |
923 | len = !i ? 1 : 1UL << (i - 1); | |
f0c29ed7 | 924 | dbg_printf("init order %lu len: %lu\n", i, len); |
4105056a | 925 | ht->t.tbl[i] = calloc(1, sizeof(struct rcu_level) |
1475579c | 926 | + (len * sizeof(struct _cds_lfht_node))); |
4105056a MD |
927 | |
928 | /* Set all dummy nodes reverse hash values for a level */ | |
929 | init_table_hash(ht, i, len); | |
930 | ||
931 | /* | |
932 | * Link all dummy nodes into the table. Concurrent | |
933 | * add/remove are helping us. | |
934 | */ | |
935 | init_table_link(ht, i, len); | |
936 | ||
937 | /* | |
938 | * Update table size (after init for now, because no | |
939 | * concurrent updater help (TODO)). | |
940 | */ | |
941 | cmm_smp_wmb(); /* populate data before RCU size */ | |
942 | CMM_STORE_SHARED(ht->t.size, !i ? 1 : (1UL << i)); | |
943 | dbg_printf("init new size: %lu\n", !i ? 1 : (1UL << i)); | |
944 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
945 | break; | |
946 | } | |
947 | } | |
948 | ||
949 | static | |
950 | void remove_table(struct cds_lfht *ht, unsigned long i, unsigned long len) | |
951 | { | |
952 | unsigned long j; | |
953 | ||
5f511391 | 954 | ht->cds_lfht_rcu_thread_online(); |
4105056a MD |
955 | ht->cds_lfht_rcu_read_lock(); |
956 | for (j = 0; j < len; j++) { | |
957 | struct cds_lfht_node *fini_node = | |
958 | (struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j]; | |
959 | ||
960 | dbg_printf("remove entry: i %lu j %lu hash %lu\n", | |
961 | i, j, !i ? 0 : (1UL << (i - 1)) + j); | |
962 | fini_node->p.reverse_hash = | |
963 | bit_reverse_ulong(!i ? 0 : (1UL << (i - 1)) + j); | |
964 | (void) _cds_lfht_remove(ht, !i ? 0 : (1UL << (i - 1)), | |
965 | fini_node, 1); | |
33c7c748 MD |
966 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
967 | break; | |
abc490a1 | 968 | } |
4105056a | 969 | ht->cds_lfht_rcu_read_unlock(); |
5f511391 | 970 | ht->cds_lfht_rcu_thread_offline(); |
2ed95849 MD |
971 | } |
972 | ||
01dbfa62 MD |
973 | /* |
974 | * Holding RCU read lock to protect _cds_lfht_remove against memory | |
975 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
976 | * problem). | |
977 | */ | |
1475579c | 978 | static |
4105056a | 979 | void fini_table(struct cds_lfht *ht, |
1475579c MD |
980 | unsigned long first_order, unsigned long len_order) |
981 | { | |
982 | long i, end_order; | |
983 | ||
984 | dbg_printf("fini table: first_order %lu end_order %lu\n", | |
985 | first_order, first_order + len_order); | |
986 | end_order = first_order + len_order; | |
987 | assert(first_order > 0); | |
4105056a | 988 | assert(ht->t.size == (1UL << (first_order - 1))); |
1475579c | 989 | for (i = end_order - 1; i >= first_order; i--) { |
4105056a | 990 | unsigned long len; |
1475579c MD |
991 | |
992 | len = !i ? 1 : 1UL << (i - 1); | |
993 | dbg_printf("fini order %lu len: %lu\n", i, len); | |
4105056a | 994 | |
21263e21 | 995 | /* |
4105056a MD |
996 | * Set "removed" flag in dummy nodes about to be removed. |
997 | * Unlink all now-logically-removed dummy node pointers. | |
998 | * Concurrent add/remove operation are helping us doing | |
999 | * the gc. | |
21263e21 | 1000 | */ |
4105056a MD |
1001 | remove_table(ht, i, len); |
1002 | ||
1003 | ht->cds_lfht_call_rcu(&ht->t.tbl[i]->head, cds_lfht_free_level); | |
1004 | ||
1005 | dbg_printf("fini new size: %lu\n", 1UL << i); | |
1475579c MD |
1006 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
1007 | break; | |
1008 | } | |
1475579c MD |
1009 | } |
1010 | ||
14044b37 MD |
1011 | struct cds_lfht *cds_lfht_new(cds_lfht_hash_fct hash_fct, |
1012 | cds_lfht_compare_fct compare_fct, | |
1013 | unsigned long hash_seed, | |
1014 | unsigned long init_size, | |
b8af5011 | 1015 | int flags, |
14044b37 | 1016 | void (*cds_lfht_call_rcu)(struct rcu_head *head, |
1475579c | 1017 | void (*func)(struct rcu_head *head)), |
01dbfa62 MD |
1018 | void (*cds_lfht_synchronize_rcu)(void), |
1019 | void (*cds_lfht_rcu_read_lock)(void), | |
5f511391 MD |
1020 | void (*cds_lfht_rcu_read_unlock)(void), |
1021 | void (*cds_lfht_rcu_thread_offline)(void), | |
1022 | void (*cds_lfht_rcu_thread_online)(void)) | |
abc490a1 | 1023 | { |
14044b37 | 1024 | struct cds_lfht *ht; |
24365af7 | 1025 | unsigned long order; |
abc490a1 | 1026 | |
8129be4e | 1027 | /* init_size must be power of two */ |
49619ea0 | 1028 | if (init_size && (init_size & (init_size - 1))) |
8129be4e | 1029 | return NULL; |
14044b37 | 1030 | ht = calloc(1, sizeof(struct cds_lfht)); |
abc490a1 | 1031 | ht->hash_fct = hash_fct; |
732ad076 MD |
1032 | ht->compare_fct = compare_fct; |
1033 | ht->hash_seed = hash_seed; | |
14044b37 | 1034 | ht->cds_lfht_call_rcu = cds_lfht_call_rcu; |
1475579c | 1035 | ht->cds_lfht_synchronize_rcu = cds_lfht_synchronize_rcu; |
01dbfa62 MD |
1036 | ht->cds_lfht_rcu_read_lock = cds_lfht_rcu_read_lock; |
1037 | ht->cds_lfht_rcu_read_unlock = cds_lfht_rcu_read_unlock; | |
5f511391 MD |
1038 | ht->cds_lfht_rcu_thread_offline = cds_lfht_rcu_thread_offline; |
1039 | ht->cds_lfht_rcu_thread_online = cds_lfht_rcu_thread_online; | |
df44348d | 1040 | ht->percpu_count = alloc_per_cpu_items_count(); |
abc490a1 MD |
1041 | /* this mutex should not nest in read-side C.S. */ |
1042 | pthread_mutex_init(&ht->resize_mutex, NULL); | |
cd95516d | 1043 | order = get_count_order_ulong(max(init_size, MIN_TABLE_SIZE)) + 1; |
b8af5011 | 1044 | ht->flags = flags; |
5f511391 | 1045 | ht->cds_lfht_rcu_thread_offline(); |
f000907d | 1046 | pthread_mutex_lock(&ht->resize_mutex); |
4105056a | 1047 | init_table(ht, 0, order); |
f000907d | 1048 | pthread_mutex_unlock(&ht->resize_mutex); |
5f511391 | 1049 | ht->cds_lfht_rcu_thread_online(); |
abc490a1 MD |
1050 | return ht; |
1051 | } | |
1052 | ||
14044b37 | 1053 | struct cds_lfht_node *cds_lfht_lookup(struct cds_lfht *ht, void *key, size_t key_len) |
2ed95849 | 1054 | { |
14044b37 MD |
1055 | struct cds_lfht_node *node, *next; |
1056 | struct _cds_lfht_node *lookup; | |
4105056a | 1057 | unsigned long hash, reverse_hash, index, order, size; |
2ed95849 | 1058 | |
732ad076 | 1059 | hash = ht->hash_fct(key, key_len, ht->hash_seed); |
abc490a1 | 1060 | reverse_hash = bit_reverse_ulong(hash); |
464a1ec9 | 1061 | |
4105056a MD |
1062 | size = rcu_dereference(ht->t.size); |
1063 | index = hash & (size - 1); | |
24365af7 | 1064 | order = get_count_order_ulong(index + 1); |
4105056a | 1065 | lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1))) - 1)]; |
f0c29ed7 | 1066 | dbg_printf("lookup hash %lu index %lu order %lu aridx %lu\n", |
554c284e | 1067 | hash, index, order, index & (!order ? 0 : ((1UL << (order - 1)) - 1))); |
14044b37 | 1068 | node = (struct cds_lfht_node *) lookup; |
2ed95849 | 1069 | for (;;) { |
abc490a1 MD |
1070 | if (unlikely(!node)) |
1071 | break; | |
cc4fcb10 | 1072 | if (unlikely(node->p.reverse_hash > reverse_hash)) { |
abc490a1 MD |
1073 | node = NULL; |
1074 | break; | |
2ed95849 | 1075 | } |
1b81fe1a MD |
1076 | next = rcu_dereference(node->p.next); |
1077 | if (likely(!is_removed(next)) | |
1078 | && !is_dummy(next) | |
49c2e2d6 | 1079 | && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) { |
273399de | 1080 | break; |
2ed95849 | 1081 | } |
1b81fe1a | 1082 | node = clear_flag(next); |
2ed95849 | 1083 | } |
1b81fe1a | 1084 | assert(!node || !is_dummy(rcu_dereference(node->p.next))); |
abc490a1 MD |
1085 | return node; |
1086 | } | |
e0ba718a | 1087 | |
a481e5ff MD |
1088 | struct cds_lfht_node *cds_lfht_next(struct cds_lfht *ht, |
1089 | struct cds_lfht_node *node) | |
1090 | { | |
1091 | struct cds_lfht_node *next; | |
1092 | unsigned long reverse_hash; | |
1093 | void *key; | |
1094 | size_t key_len; | |
1095 | ||
1096 | reverse_hash = node->p.reverse_hash; | |
1097 | key = node->key; | |
1098 | key_len = node->key_len; | |
1099 | next = rcu_dereference(node->p.next); | |
1100 | node = clear_flag(next); | |
1101 | ||
1102 | for (;;) { | |
1103 | if (unlikely(!node)) | |
1104 | break; | |
1105 | if (unlikely(node->p.reverse_hash > reverse_hash)) { | |
1106 | node = NULL; | |
1107 | break; | |
1108 | } | |
1109 | next = rcu_dereference(node->p.next); | |
1110 | if (likely(!is_removed(next)) | |
1111 | && !is_dummy(next) | |
1112 | && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) { | |
1113 | break; | |
1114 | } | |
1115 | node = clear_flag(next); | |
1116 | } | |
1117 | assert(!node || !is_dummy(rcu_dereference(node->p.next))); | |
1118 | return node; | |
1119 | } | |
1120 | ||
14044b37 | 1121 | void cds_lfht_add(struct cds_lfht *ht, struct cds_lfht_node *node) |
abc490a1 | 1122 | { |
4105056a | 1123 | unsigned long hash, size; |
ab7d5fc6 | 1124 | |
49c2e2d6 | 1125 | hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed); |
cc4fcb10 | 1126 | node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash); |
2ed95849 | 1127 | |
4105056a MD |
1128 | size = rcu_dereference(ht->t.size); |
1129 | (void) _cds_lfht_add(ht, size, node, 0, 0); | |
1130 | ht_count_add(ht, size); | |
3eca1b8c MD |
1131 | } |
1132 | ||
14044b37 MD |
1133 | struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, |
1134 | struct cds_lfht_node *node) | |
3eca1b8c | 1135 | { |
4105056a | 1136 | unsigned long hash, size; |
df44348d | 1137 | struct cds_lfht_node *ret; |
3eca1b8c | 1138 | |
49c2e2d6 | 1139 | hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed); |
cc4fcb10 | 1140 | node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash); |
3eca1b8c | 1141 | |
4105056a MD |
1142 | size = rcu_dereference(ht->t.size); |
1143 | ret = _cds_lfht_add(ht, size, node, 1, 0); | |
df44348d | 1144 | if (ret != node) |
4105056a | 1145 | ht_count_add(ht, size); |
df44348d | 1146 | return ret; |
2ed95849 MD |
1147 | } |
1148 | ||
14044b37 | 1149 | int cds_lfht_remove(struct cds_lfht *ht, struct cds_lfht_node *node) |
2ed95849 | 1150 | { |
4105056a | 1151 | unsigned long size; |
df44348d | 1152 | int ret; |
abc490a1 | 1153 | |
4105056a MD |
1154 | size = rcu_dereference(ht->t.size); |
1155 | ret = _cds_lfht_remove(ht, size, node, 0); | |
df44348d | 1156 | if (!ret) |
4105056a | 1157 | ht_count_remove(ht, size); |
df44348d | 1158 | return ret; |
2ed95849 | 1159 | } |
ab7d5fc6 | 1160 | |
abc490a1 | 1161 | static |
14044b37 | 1162 | int cds_lfht_delete_dummy(struct cds_lfht *ht) |
674f7a69 | 1163 | { |
14044b37 MD |
1164 | struct cds_lfht_node *node; |
1165 | struct _cds_lfht_node *lookup; | |
4105056a | 1166 | unsigned long order, i, size; |
674f7a69 | 1167 | |
abc490a1 | 1168 | /* Check that the table is empty */ |
4105056a | 1169 | lookup = &ht->t.tbl[0]->nodes[0]; |
14044b37 | 1170 | node = (struct cds_lfht_node *) lookup; |
abc490a1 | 1171 | do { |
1b81fe1a MD |
1172 | node = clear_flag(node)->p.next; |
1173 | if (!is_dummy(node)) | |
abc490a1 | 1174 | return -EPERM; |
273399de | 1175 | assert(!is_removed(node)); |
a2974903 | 1176 | } while (clear_flag(node)); |
4105056a MD |
1177 | /* |
1178 | * size accessed without rcu_dereference because hash table is | |
1179 | * being destroyed. | |
1180 | */ | |
1181 | size = ht->t.size; | |
abc490a1 | 1182 | /* Internal sanity check: all nodes left should be dummy */ |
4105056a | 1183 | for (order = 0; order < get_count_order_ulong(size) + 1; order++) { |
24365af7 MD |
1184 | unsigned long len; |
1185 | ||
1186 | len = !order ? 1 : 1UL << (order - 1); | |
1187 | for (i = 0; i < len; i++) { | |
f0c29ed7 | 1188 | dbg_printf("delete order %lu i %lu hash %lu\n", |
24365af7 | 1189 | order, i, |
4105056a MD |
1190 | bit_reverse_ulong(ht->t.tbl[order]->nodes[i].reverse_hash)); |
1191 | assert(is_dummy(ht->t.tbl[order]->nodes[i].next)); | |
24365af7 | 1192 | } |
4105056a | 1193 | poison_free(ht->t.tbl[order]); |
674f7a69 | 1194 | } |
abc490a1 | 1195 | return 0; |
674f7a69 MD |
1196 | } |
1197 | ||
1198 | /* | |
1199 | * Should only be called when no more concurrent readers nor writers can | |
1200 | * possibly access the table. | |
1201 | */ | |
14044b37 | 1202 | int cds_lfht_destroy(struct cds_lfht *ht) |
674f7a69 | 1203 | { |
5e28c532 MD |
1204 | int ret; |
1205 | ||
848d4088 | 1206 | /* Wait for in-flight resize operations to complete */ |
33c7c748 | 1207 | CMM_STORE_SHARED(ht->in_progress_destroy, 1); |
848d4088 MD |
1208 | while (uatomic_read(&ht->in_progress_resize)) |
1209 | poll(NULL, 0, 100); /* wait for 100ms */ | |
14044b37 | 1210 | ret = cds_lfht_delete_dummy(ht); |
abc490a1 MD |
1211 | if (ret) |
1212 | return ret; | |
df44348d | 1213 | free_per_cpu_items_count(ht->percpu_count); |
98808fb1 | 1214 | poison_free(ht); |
5e28c532 | 1215 | return ret; |
674f7a69 MD |
1216 | } |
1217 | ||
14044b37 | 1218 | void cds_lfht_count_nodes(struct cds_lfht *ht, |
273399de MD |
1219 | unsigned long *count, |
1220 | unsigned long *removed) | |
1221 | { | |
14044b37 MD |
1222 | struct cds_lfht_node *node, *next; |
1223 | struct _cds_lfht_node *lookup; | |
24365af7 | 1224 | unsigned long nr_dummy = 0; |
273399de MD |
1225 | |
1226 | *count = 0; | |
1227 | *removed = 0; | |
1228 | ||
24365af7 | 1229 | /* Count non-dummy nodes in the table */ |
4105056a | 1230 | lookup = &ht->t.tbl[0]->nodes[0]; |
14044b37 | 1231 | node = (struct cds_lfht_node *) lookup; |
273399de | 1232 | do { |
cc4fcb10 | 1233 | next = rcu_dereference(node->p.next); |
273399de | 1234 | if (is_removed(next)) { |
1b81fe1a | 1235 | assert(!is_dummy(next)); |
273399de | 1236 | (*removed)++; |
1b81fe1a | 1237 | } else if (!is_dummy(next)) |
273399de | 1238 | (*count)++; |
24365af7 MD |
1239 | else |
1240 | (nr_dummy)++; | |
273399de MD |
1241 | node = clear_flag(next); |
1242 | } while (node); | |
f0c29ed7 | 1243 | dbg_printf("number of dummy nodes: %lu\n", nr_dummy); |
273399de MD |
1244 | } |
1245 | ||
1475579c | 1246 | /* called with resize mutex held */ |
abc490a1 | 1247 | static |
4105056a | 1248 | void _do_cds_lfht_grow(struct cds_lfht *ht, |
1475579c | 1249 | unsigned long old_size, unsigned long new_size) |
abc490a1 | 1250 | { |
1475579c | 1251 | unsigned long old_order, new_order; |
1475579c MD |
1252 | |
1253 | old_order = get_count_order_ulong(old_size) + 1; | |
1254 | new_order = get_count_order_ulong(new_size) + 1; | |
1255 | printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", | |
1256 | old_size, old_order, new_size, new_order); | |
1475579c | 1257 | assert(new_size > old_size); |
4105056a | 1258 | init_table(ht, old_order, new_order - old_order); |
abc490a1 MD |
1259 | } |
1260 | ||
1261 | /* called with resize mutex held */ | |
1262 | static | |
4105056a | 1263 | void _do_cds_lfht_shrink(struct cds_lfht *ht, |
1475579c | 1264 | unsigned long old_size, unsigned long new_size) |
464a1ec9 | 1265 | { |
1475579c | 1266 | unsigned long old_order, new_order; |
464a1ec9 | 1267 | |
cd95516d | 1268 | new_size = max(new_size, MIN_TABLE_SIZE); |
24365af7 | 1269 | old_order = get_count_order_ulong(old_size) + 1; |
24365af7 | 1270 | new_order = get_count_order_ulong(new_size) + 1; |
df44348d | 1271 | printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", |
df03fab8 | 1272 | old_size, old_order, new_size, new_order); |
1475579c | 1273 | assert(new_size < old_size); |
1475579c | 1274 | |
4105056a MD |
1275 | cmm_smp_wmb(); /* populate data before RCU size */ |
1276 | CMM_STORE_SHARED(ht->t.size, new_size); | |
1475579c MD |
1277 | |
1278 | /* | |
c90201ac | 1279 | * We need to wait for all add operations to reach Q.S. (and |
1475579c | 1280 | * thus use the new table for lookups) before we can start |
c90201ac MD |
1281 | * releasing the old dummy nodes. Otherwise their lookup will |
1282 | * return a logically removed node as insert position. | |
1475579c MD |
1283 | */ |
1284 | ht->cds_lfht_synchronize_rcu(); | |
1285 | ||
4105056a MD |
1286 | /* Remove and unlink all dummy nodes to remove. */ |
1287 | fini_table(ht, new_order, old_order - new_order); | |
464a1ec9 MD |
1288 | } |
1289 | ||
1475579c MD |
1290 | |
1291 | /* called with resize mutex held */ | |
1292 | static | |
1293 | void _do_cds_lfht_resize(struct cds_lfht *ht) | |
1294 | { | |
1295 | unsigned long new_size, old_size; | |
4105056a MD |
1296 | |
1297 | /* | |
1298 | * Resize table, re-do if the target size has changed under us. | |
1299 | */ | |
1300 | do { | |
1301 | ht->t.resize_initiated = 1; | |
1302 | old_size = ht->t.size; | |
1303 | new_size = CMM_LOAD_SHARED(ht->t.resize_target); | |
1304 | if (old_size < new_size) | |
1305 | _do_cds_lfht_grow(ht, old_size, new_size); | |
1306 | else if (old_size > new_size) | |
1307 | _do_cds_lfht_shrink(ht, old_size, new_size); | |
1308 | ht->t.resize_initiated = 0; | |
1309 | /* write resize_initiated before read resize_target */ | |
1310 | cmm_smp_mb(); | |
1311 | } while (new_size != CMM_LOAD_SHARED(ht->t.resize_target)); | |
1475579c MD |
1312 | } |
1313 | ||
abc490a1 | 1314 | static |
4105056a | 1315 | unsigned long resize_target_update(struct cds_lfht *ht, unsigned long size, |
f9830efd | 1316 | int growth_order) |
464a1ec9 | 1317 | { |
4105056a MD |
1318 | return _uatomic_max(&ht->t.resize_target, |
1319 | size << growth_order); | |
464a1ec9 MD |
1320 | } |
1321 | ||
1475579c | 1322 | static |
4105056a | 1323 | void resize_target_update_count(struct cds_lfht *ht, |
b8af5011 | 1324 | unsigned long count) |
1475579c | 1325 | { |
cd95516d | 1326 | count = max(count, MIN_TABLE_SIZE); |
4105056a | 1327 | uatomic_set(&ht->t.resize_target, count); |
1475579c MD |
1328 | } |
1329 | ||
1330 | void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size) | |
464a1ec9 | 1331 | { |
4105056a MD |
1332 | resize_target_update_count(ht, new_size); |
1333 | CMM_STORE_SHARED(ht->t.resize_initiated, 1); | |
5f511391 | 1334 | ht->cds_lfht_rcu_thread_offline(); |
1475579c MD |
1335 | pthread_mutex_lock(&ht->resize_mutex); |
1336 | _do_cds_lfht_resize(ht); | |
1337 | pthread_mutex_unlock(&ht->resize_mutex); | |
5f511391 | 1338 | ht->cds_lfht_rcu_thread_online(); |
abc490a1 | 1339 | } |
464a1ec9 | 1340 | |
abc490a1 MD |
1341 | static |
1342 | void do_resize_cb(struct rcu_head *head) | |
1343 | { | |
1344 | struct rcu_resize_work *work = | |
1345 | caa_container_of(head, struct rcu_resize_work, head); | |
14044b37 | 1346 | struct cds_lfht *ht = work->ht; |
abc490a1 | 1347 | |
5f511391 | 1348 | ht->cds_lfht_rcu_thread_offline(); |
abc490a1 | 1349 | pthread_mutex_lock(&ht->resize_mutex); |
14044b37 | 1350 | _do_cds_lfht_resize(ht); |
abc490a1 | 1351 | pthread_mutex_unlock(&ht->resize_mutex); |
5f511391 | 1352 | ht->cds_lfht_rcu_thread_online(); |
98808fb1 | 1353 | poison_free(work); |
848d4088 MD |
1354 | cmm_smp_mb(); /* finish resize before decrement */ |
1355 | uatomic_dec(&ht->in_progress_resize); | |
464a1ec9 MD |
1356 | } |
1357 | ||
abc490a1 | 1358 | static |
4105056a | 1359 | void cds_lfht_resize_lazy(struct cds_lfht *ht, unsigned long size, int growth) |
ab7d5fc6 | 1360 | { |
abc490a1 | 1361 | struct rcu_resize_work *work; |
f9830efd | 1362 | unsigned long target_size; |
abc490a1 | 1363 | |
4105056a MD |
1364 | target_size = resize_target_update(ht, size, growth); |
1365 | /* Store resize_target before read resize_initiated */ | |
1366 | cmm_smp_mb(); | |
1367 | if (!CMM_LOAD_SHARED(ht->t.resize_initiated) && size < target_size) { | |
848d4088 MD |
1368 | uatomic_inc(&ht->in_progress_resize); |
1369 | cmm_smp_mb(); /* increment resize count before calling it */ | |
f9830efd MD |
1370 | work = malloc(sizeof(*work)); |
1371 | work->ht = ht; | |
14044b37 | 1372 | ht->cds_lfht_call_rcu(&work->head, do_resize_cb); |
4105056a | 1373 | CMM_STORE_SHARED(ht->t.resize_initiated, 1); |
f9830efd | 1374 | } |
ab7d5fc6 | 1375 | } |
3171717f | 1376 | |
f8994aee MD |
1377 | #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) |
1378 | ||
3171717f | 1379 | static |
4105056a | 1380 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, |
3171717f MD |
1381 | unsigned long count) |
1382 | { | |
1383 | struct rcu_resize_work *work; | |
3171717f | 1384 | |
b8af5011 MD |
1385 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) |
1386 | return; | |
4105056a MD |
1387 | resize_target_update_count(ht, count); |
1388 | /* Store resize_target before read resize_initiated */ | |
1389 | cmm_smp_mb(); | |
1390 | if (!CMM_LOAD_SHARED(ht->t.resize_initiated)) { | |
3171717f MD |
1391 | uatomic_inc(&ht->in_progress_resize); |
1392 | cmm_smp_mb(); /* increment resize count before calling it */ | |
1393 | work = malloc(sizeof(*work)); | |
1394 | work->ht = ht; | |
1395 | ht->cds_lfht_call_rcu(&work->head, do_resize_cb); | |
4105056a | 1396 | CMM_STORE_SHARED(ht->t.resize_initiated, 1); |
3171717f MD |
1397 | } |
1398 | } | |
f8994aee MD |
1399 | |
1400 | #endif |