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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 | ||
abc490a1 MD |
179 | #ifndef max |
180 | #define max(a, b) ((a) > (b) ? (a) : (b)) | |
181 | #endif | |
2ed95849 | 182 | |
d95bd160 MD |
183 | /* |
184 | * The removed flag needs to be updated atomically with the pointer. | |
185 | * The dummy flag does not require to be updated atomically with the | |
186 | * pointer, but it is added as a pointer low bit flag to save space. | |
187 | */ | |
d37166c6 | 188 | #define REMOVED_FLAG (1UL << 0) |
f5596c94 MD |
189 | #define DUMMY_FLAG (1UL << 1) |
190 | #define FLAGS_MASK ((1UL << 2) - 1) | |
d37166c6 | 191 | |
df44348d | 192 | struct ht_items_count { |
3171717f | 193 | unsigned long add, remove; |
df44348d MD |
194 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
195 | ||
1475579c MD |
196 | struct rcu_level { |
197 | struct rcu_head head; | |
198 | struct _cds_lfht_node nodes[0]; | |
199 | }; | |
200 | ||
395270b6 | 201 | struct rcu_table { |
abc490a1 | 202 | unsigned long size; /* always a power of 2 */ |
f9830efd | 203 | unsigned long resize_target; |
11519af6 | 204 | int resize_initiated; |
abc490a1 | 205 | struct rcu_head head; |
1475579c | 206 | struct rcu_level *tbl[0]; |
395270b6 MD |
207 | }; |
208 | ||
14044b37 | 209 | struct cds_lfht { |
395270b6 | 210 | struct rcu_table *t; /* shared */ |
14044b37 MD |
211 | cds_lfht_hash_fct hash_fct; |
212 | cds_lfht_compare_fct compare_fct; | |
732ad076 | 213 | unsigned long hash_seed; |
b8af5011 | 214 | int flags; |
464a1ec9 | 215 | pthread_mutex_t resize_mutex; /* resize mutex: add/del mutex */ |
33c7c748 | 216 | unsigned int in_progress_resize, in_progress_destroy; |
14044b37 | 217 | void (*cds_lfht_call_rcu)(struct rcu_head *head, |
abc490a1 | 218 | void (*func)(struct rcu_head *head)); |
1475579c | 219 | void (*cds_lfht_synchronize_rcu)(void); |
01dbfa62 MD |
220 | void (*cds_lfht_rcu_read_lock)(void); |
221 | void (*cds_lfht_rcu_read_unlock)(void); | |
df44348d MD |
222 | unsigned long count; /* global approximate item count */ |
223 | struct ht_items_count *percpu_count; /* per-cpu item count */ | |
2ed95849 MD |
224 | }; |
225 | ||
abc490a1 MD |
226 | struct rcu_resize_work { |
227 | struct rcu_head head; | |
14044b37 | 228 | struct cds_lfht *ht; |
abc490a1 | 229 | }; |
2ed95849 | 230 | |
abc490a1 MD |
231 | /* |
232 | * Algorithm to reverse bits in a word by lookup table, extended to | |
233 | * 64-bit words. | |
f9830efd | 234 | * Source: |
abc490a1 | 235 | * http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable |
f9830efd | 236 | * Originally from Public Domain. |
abc490a1 MD |
237 | */ |
238 | ||
239 | static const uint8_t BitReverseTable256[256] = | |
2ed95849 | 240 | { |
abc490a1 MD |
241 | #define R2(n) (n), (n) + 2*64, (n) + 1*64, (n) + 3*64 |
242 | #define R4(n) R2(n), R2((n) + 2*16), R2((n) + 1*16), R2((n) + 3*16) | |
243 | #define R6(n) R4(n), R4((n) + 2*4 ), R4((n) + 1*4 ), R4((n) + 3*4 ) | |
244 | R6(0), R6(2), R6(1), R6(3) | |
245 | }; | |
246 | #undef R2 | |
247 | #undef R4 | |
248 | #undef R6 | |
2ed95849 | 249 | |
abc490a1 MD |
250 | static |
251 | uint8_t bit_reverse_u8(uint8_t v) | |
252 | { | |
253 | return BitReverseTable256[v]; | |
254 | } | |
ab7d5fc6 | 255 | |
abc490a1 MD |
256 | static __attribute__((unused)) |
257 | uint32_t bit_reverse_u32(uint32_t v) | |
258 | { | |
259 | return ((uint32_t) bit_reverse_u8(v) << 24) | | |
260 | ((uint32_t) bit_reverse_u8(v >> 8) << 16) | | |
261 | ((uint32_t) bit_reverse_u8(v >> 16) << 8) | | |
262 | ((uint32_t) bit_reverse_u8(v >> 24)); | |
2ed95849 MD |
263 | } |
264 | ||
abc490a1 MD |
265 | static __attribute__((unused)) |
266 | uint64_t bit_reverse_u64(uint64_t v) | |
2ed95849 | 267 | { |
abc490a1 MD |
268 | return ((uint64_t) bit_reverse_u8(v) << 56) | |
269 | ((uint64_t) bit_reverse_u8(v >> 8) << 48) | | |
270 | ((uint64_t) bit_reverse_u8(v >> 16) << 40) | | |
271 | ((uint64_t) bit_reverse_u8(v >> 24) << 32) | | |
272 | ((uint64_t) bit_reverse_u8(v >> 32) << 24) | | |
273 | ((uint64_t) bit_reverse_u8(v >> 40) << 16) | | |
274 | ((uint64_t) bit_reverse_u8(v >> 48) << 8) | | |
275 | ((uint64_t) bit_reverse_u8(v >> 56)); | |
276 | } | |
277 | ||
278 | static | |
279 | unsigned long bit_reverse_ulong(unsigned long v) | |
280 | { | |
281 | #if (CAA_BITS_PER_LONG == 32) | |
282 | return bit_reverse_u32(v); | |
283 | #else | |
284 | return bit_reverse_u64(v); | |
285 | #endif | |
286 | } | |
287 | ||
f9830efd | 288 | /* |
24365af7 MD |
289 | * fls: returns the position of the most significant bit. |
290 | * Returns 0 if no bit is set, else returns the position of the most | |
291 | * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit). | |
f9830efd | 292 | */ |
24365af7 MD |
293 | #if defined(__i386) || defined(__x86_64) |
294 | static inline | |
295 | unsigned int fls_u32(uint32_t x) | |
f9830efd | 296 | { |
24365af7 MD |
297 | int r; |
298 | ||
299 | asm("bsrl %1,%0\n\t" | |
300 | "jnz 1f\n\t" | |
301 | "movl $-1,%0\n\t" | |
302 | "1:\n\t" | |
303 | : "=r" (r) : "rm" (x)); | |
304 | return r + 1; | |
305 | } | |
306 | #define HAS_FLS_U32 | |
307 | #endif | |
308 | ||
309 | #if defined(__x86_64) | |
310 | static inline | |
311 | unsigned int fls_u64(uint64_t x) | |
312 | { | |
313 | long r; | |
314 | ||
315 | asm("bsrq %1,%0\n\t" | |
316 | "jnz 1f\n\t" | |
317 | "movq $-1,%0\n\t" | |
318 | "1:\n\t" | |
319 | : "=r" (r) : "rm" (x)); | |
320 | return r + 1; | |
321 | } | |
322 | #define HAS_FLS_U64 | |
323 | #endif | |
324 | ||
325 | #ifndef HAS_FLS_U64 | |
326 | static __attribute__((unused)) | |
327 | unsigned int fls_u64(uint64_t x) | |
328 | { | |
329 | unsigned int r = 64; | |
330 | ||
331 | if (!x) | |
332 | return 0; | |
333 | ||
334 | if (!(x & 0xFFFFFFFF00000000ULL)) { | |
335 | x <<= 32; | |
336 | r -= 32; | |
337 | } | |
338 | if (!(x & 0xFFFF000000000000ULL)) { | |
339 | x <<= 16; | |
340 | r -= 16; | |
341 | } | |
342 | if (!(x & 0xFF00000000000000ULL)) { | |
343 | x <<= 8; | |
344 | r -= 8; | |
345 | } | |
346 | if (!(x & 0xF000000000000000ULL)) { | |
347 | x <<= 4; | |
348 | r -= 4; | |
349 | } | |
350 | if (!(x & 0xC000000000000000ULL)) { | |
351 | x <<= 2; | |
352 | r -= 2; | |
353 | } | |
354 | if (!(x & 0x8000000000000000ULL)) { | |
355 | x <<= 1; | |
356 | r -= 1; | |
357 | } | |
358 | return r; | |
359 | } | |
360 | #endif | |
361 | ||
362 | #ifndef HAS_FLS_U32 | |
363 | static __attribute__((unused)) | |
364 | unsigned int fls_u32(uint32_t x) | |
365 | { | |
366 | unsigned int r = 32; | |
f9830efd | 367 | |
24365af7 MD |
368 | if (!x) |
369 | return 0; | |
370 | if (!(x & 0xFFFF0000U)) { | |
371 | x <<= 16; | |
372 | r -= 16; | |
373 | } | |
374 | if (!(x & 0xFF000000U)) { | |
375 | x <<= 8; | |
376 | r -= 8; | |
377 | } | |
378 | if (!(x & 0xF0000000U)) { | |
379 | x <<= 4; | |
380 | r -= 4; | |
381 | } | |
382 | if (!(x & 0xC0000000U)) { | |
383 | x <<= 2; | |
384 | r -= 2; | |
385 | } | |
386 | if (!(x & 0x80000000U)) { | |
387 | x <<= 1; | |
388 | r -= 1; | |
389 | } | |
390 | return r; | |
391 | } | |
392 | #endif | |
393 | ||
394 | unsigned int fls_ulong(unsigned long x) | |
f9830efd | 395 | { |
24365af7 MD |
396 | #if (CAA_BITS_PER_lONG == 32) |
397 | return fls_u32(x); | |
398 | #else | |
399 | return fls_u64(x); | |
400 | #endif | |
401 | } | |
f9830efd | 402 | |
24365af7 MD |
403 | int get_count_order_u32(uint32_t x) |
404 | { | |
405 | int order; | |
406 | ||
407 | order = fls_u32(x) - 1; | |
408 | if (x & (x - 1)) | |
409 | order++; | |
410 | return order; | |
411 | } | |
412 | ||
413 | int get_count_order_ulong(unsigned long x) | |
414 | { | |
415 | int order; | |
416 | ||
417 | order = fls_ulong(x) - 1; | |
418 | if (x & (x - 1)) | |
419 | order++; | |
420 | return order; | |
f9830efd MD |
421 | } |
422 | ||
98808fb1 MD |
423 | #ifdef POISON_FREE |
424 | #define poison_free(ptr) \ | |
425 | do { \ | |
426 | memset(ptr, 0x42, sizeof(*(ptr))); \ | |
427 | free(ptr); \ | |
428 | } while (0) | |
429 | #else | |
430 | #define poison_free(ptr) free(ptr) | |
431 | #endif | |
432 | ||
f9830efd | 433 | static |
14044b37 | 434 | void cds_lfht_resize_lazy(struct cds_lfht *ht, struct rcu_table *t, int growth); |
f9830efd | 435 | |
df44348d MD |
436 | /* |
437 | * If the sched_getcpu() and sysconf(_SC_NPROCESSORS_CONF) calls are | |
438 | * available, then we support hash table item accounting. | |
439 | * In the unfortunate event the number of CPUs reported would be | |
440 | * inaccurate, we use modulo arithmetic on the number of CPUs we got. | |
441 | */ | |
df44348d MD |
442 | #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) |
443 | ||
f8994aee MD |
444 | static |
445 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, struct rcu_table *t, | |
446 | unsigned long count); | |
447 | ||
df44348d MD |
448 | static long nr_cpus_mask = -1; |
449 | ||
450 | static | |
451 | struct ht_items_count *alloc_per_cpu_items_count(void) | |
452 | { | |
453 | struct ht_items_count *count; | |
454 | ||
455 | switch (nr_cpus_mask) { | |
456 | case -2: | |
457 | return NULL; | |
458 | case -1: | |
459 | { | |
460 | long maxcpus; | |
461 | ||
462 | maxcpus = sysconf(_SC_NPROCESSORS_CONF); | |
463 | if (maxcpus <= 0) { | |
464 | nr_cpus_mask = -2; | |
465 | return NULL; | |
466 | } | |
467 | /* | |
468 | * round up number of CPUs to next power of two, so we | |
469 | * can use & for modulo. | |
470 | */ | |
471 | maxcpus = 1UL << get_count_order_ulong(maxcpus); | |
472 | nr_cpus_mask = maxcpus - 1; | |
473 | } | |
474 | /* Fall-through */ | |
475 | default: | |
476 | return calloc(nr_cpus_mask + 1, sizeof(*count)); | |
477 | } | |
478 | } | |
479 | ||
480 | static | |
481 | void free_per_cpu_items_count(struct ht_items_count *count) | |
482 | { | |
98808fb1 | 483 | poison_free(count); |
df44348d MD |
484 | } |
485 | ||
486 | static | |
487 | int ht_get_cpu(void) | |
488 | { | |
489 | int cpu; | |
490 | ||
491 | assert(nr_cpus_mask >= 0); | |
492 | cpu = sched_getcpu(); | |
493 | if (unlikely(cpu < 0)) | |
494 | return cpu; | |
495 | else | |
496 | return cpu & nr_cpus_mask; | |
497 | } | |
498 | ||
499 | static | |
3171717f | 500 | void ht_count_add(struct cds_lfht *ht, struct rcu_table *t) |
df44348d | 501 | { |
3171717f | 502 | unsigned long percpu_count; |
df44348d MD |
503 | int cpu; |
504 | ||
505 | if (unlikely(!ht->percpu_count)) | |
3171717f | 506 | return; |
df44348d MD |
507 | cpu = ht_get_cpu(); |
508 | if (unlikely(cpu < 0)) | |
3171717f MD |
509 | return; |
510 | percpu_count = uatomic_add_return(&ht->percpu_count[cpu].add, 1); | |
df44348d MD |
511 | if (unlikely(!(percpu_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) { |
512 | unsigned long count; | |
513 | ||
514 | dbg_printf("add percpu %lu\n", percpu_count); | |
515 | count = uatomic_add_return(&ht->count, | |
516 | 1UL << COUNT_COMMIT_ORDER); | |
517 | /* If power of 2 */ | |
518 | if (!(count & (count - 1))) { | |
f8994aee MD |
519 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) |
520 | < t->size) | |
521 | return; | |
522 | dbg_printf("add set global %lu\n", count); | |
523 | cds_lfht_resize_lazy_count(ht, t, | |
6ea6bc67 | 524 | count >> (CHAIN_LEN_TARGET - 1)); |
df44348d MD |
525 | } |
526 | } | |
527 | } | |
528 | ||
529 | static | |
530 | void ht_count_remove(struct cds_lfht *ht, struct rcu_table *t) | |
531 | { | |
532 | unsigned long percpu_count; | |
3171717f | 533 | int cpu; |
df44348d | 534 | |
3171717f MD |
535 | if (unlikely(!ht->percpu_count)) |
536 | return; | |
537 | cpu = ht_get_cpu(); | |
538 | if (unlikely(cpu < 0)) | |
539 | return; | |
540 | percpu_count = uatomic_add_return(&ht->percpu_count[cpu].remove, -1); | |
df44348d MD |
541 | if (unlikely(!(percpu_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) { |
542 | unsigned long count; | |
543 | ||
544 | dbg_printf("remove percpu %lu\n", percpu_count); | |
545 | count = uatomic_add_return(&ht->count, | |
3171717f | 546 | -(1UL << COUNT_COMMIT_ORDER)); |
df44348d MD |
547 | /* If power of 2 */ |
548 | if (!(count & (count - 1))) { | |
f8994aee MD |
549 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) |
550 | >= t->size) | |
551 | return; | |
552 | dbg_printf("remove set global %lu\n", count); | |
553 | cds_lfht_resize_lazy_count(ht, t, | |
6ea6bc67 | 554 | count >> (CHAIN_LEN_TARGET - 1)); |
df44348d MD |
555 | } |
556 | } | |
557 | } | |
558 | ||
559 | #else /* #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */ | |
560 | ||
561 | static const long nr_cpus_mask = -1; | |
562 | ||
563 | static | |
564 | struct ht_items_count *alloc_per_cpu_items_count(void) | |
565 | { | |
566 | return NULL; | |
567 | } | |
568 | ||
569 | static | |
570 | void free_per_cpu_items_count(struct ht_items_count *count) | |
571 | { | |
572 | } | |
573 | ||
574 | static | |
f8994aee | 575 | void ht_count_add(struct cds_lfht *ht, struct rcu_table *t) |
df44348d MD |
576 | { |
577 | } | |
578 | ||
579 | static | |
f8994aee | 580 | void ht_count_remove(struct cds_lfht *ht, struct rcu_table *t) |
df44348d MD |
581 | { |
582 | } | |
583 | ||
584 | #endif /* #else #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */ | |
585 | ||
586 | ||
f9830efd | 587 | static |
14044b37 | 588 | void check_resize(struct cds_lfht *ht, struct rcu_table *t, |
f9830efd MD |
589 | uint32_t chain_len) |
590 | { | |
f8994aee MD |
591 | unsigned long count; |
592 | ||
b8af5011 MD |
593 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) |
594 | return; | |
f8994aee MD |
595 | count = uatomic_read(&ht->count); |
596 | /* | |
597 | * Use bucket-local length for small table expand and for | |
598 | * environments lacking per-cpu data support. | |
599 | */ | |
600 | if (count >= (1UL << COUNT_COMMIT_ORDER)) | |
601 | return; | |
24365af7 | 602 | if (chain_len > 100) |
f0c29ed7 | 603 | dbg_printf("WARNING: large chain length: %u.\n", |
24365af7 | 604 | chain_len); |
3390d470 | 605 | if (chain_len >= CHAIN_LEN_RESIZE_THRESHOLD) |
14044b37 | 606 | cds_lfht_resize_lazy(ht, t, |
01370f0b | 607 | get_count_order_u32(chain_len - (CHAIN_LEN_TARGET - 1))); |
f9830efd MD |
608 | } |
609 | ||
abc490a1 | 610 | static |
14044b37 | 611 | struct cds_lfht_node *clear_flag(struct cds_lfht_node *node) |
abc490a1 | 612 | { |
14044b37 | 613 | return (struct cds_lfht_node *) (((unsigned long) node) & ~FLAGS_MASK); |
abc490a1 MD |
614 | } |
615 | ||
616 | static | |
14044b37 | 617 | int is_removed(struct cds_lfht_node *node) |
abc490a1 | 618 | { |
d37166c6 | 619 | return ((unsigned long) node) & REMOVED_FLAG; |
abc490a1 MD |
620 | } |
621 | ||
622 | static | |
14044b37 | 623 | struct cds_lfht_node *flag_removed(struct cds_lfht_node *node) |
abc490a1 | 624 | { |
14044b37 | 625 | return (struct cds_lfht_node *) (((unsigned long) node) | REMOVED_FLAG); |
abc490a1 MD |
626 | } |
627 | ||
f5596c94 | 628 | static |
14044b37 | 629 | int is_dummy(struct cds_lfht_node *node) |
f5596c94 MD |
630 | { |
631 | return ((unsigned long) node) & DUMMY_FLAG; | |
632 | } | |
633 | ||
634 | static | |
14044b37 | 635 | struct cds_lfht_node *flag_dummy(struct cds_lfht_node *node) |
f5596c94 | 636 | { |
14044b37 | 637 | return (struct cds_lfht_node *) (((unsigned long) node) | DUMMY_FLAG); |
f5596c94 MD |
638 | } |
639 | ||
abc490a1 | 640 | static |
f9830efd | 641 | unsigned long _uatomic_max(unsigned long *ptr, unsigned long v) |
abc490a1 MD |
642 | { |
643 | unsigned long old1, old2; | |
644 | ||
645 | old1 = uatomic_read(ptr); | |
646 | do { | |
647 | old2 = old1; | |
648 | if (old2 >= v) | |
f9830efd | 649 | return old2; |
abc490a1 | 650 | } while ((old1 = uatomic_cmpxchg(ptr, old2, v)) != old2); |
f9830efd | 651 | return v; |
abc490a1 MD |
652 | } |
653 | ||
1475579c MD |
654 | static |
655 | void cds_lfht_free_table_cb(struct rcu_head *head) | |
656 | { | |
657 | struct rcu_table *t = | |
658 | caa_container_of(head, struct rcu_table, head); | |
98808fb1 | 659 | poison_free(t); |
1475579c MD |
660 | } |
661 | ||
662 | static | |
663 | void cds_lfht_free_level(struct rcu_head *head) | |
664 | { | |
665 | struct rcu_level *l = | |
666 | caa_container_of(head, struct rcu_level, head); | |
98808fb1 | 667 | poison_free(l); |
1475579c MD |
668 | } |
669 | ||
273399de MD |
670 | /* |
671 | * Remove all logically deleted nodes from a bucket up to a certain node key. | |
672 | */ | |
673 | static | |
14044b37 | 674 | void _cds_lfht_gc_bucket(struct cds_lfht_node *dummy, struct cds_lfht_node *node) |
273399de | 675 | { |
14044b37 | 676 | struct cds_lfht_node *iter_prev, *iter, *next, *new_next; |
273399de | 677 | |
c90201ac MD |
678 | assert(!is_dummy(dummy)); |
679 | assert(!is_removed(dummy)); | |
680 | assert(!is_dummy(node)); | |
681 | assert(!is_removed(node)); | |
273399de MD |
682 | for (;;) { |
683 | iter_prev = dummy; | |
684 | /* We can always skip the dummy node initially */ | |
cc4fcb10 MD |
685 | iter = rcu_dereference(iter_prev->p.next); |
686 | assert(iter_prev->p.reverse_hash <= node->p.reverse_hash); | |
bd4db153 MD |
687 | /* |
688 | * We should never be called with dummy (start of chain) | |
689 | * and logically removed node (end of path compression | |
690 | * marker) being the actual same node. This would be a | |
691 | * bug in the algorithm implementation. | |
692 | */ | |
693 | assert(dummy != node); | |
273399de | 694 | for (;;) { |
a2974903 | 695 | if (unlikely(!clear_flag(iter))) |
479c8a32 | 696 | return; |
76412f24 | 697 | if (likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash)) |
273399de | 698 | return; |
cc4fcb10 | 699 | next = rcu_dereference(clear_flag(iter)->p.next); |
76412f24 | 700 | if (likely(is_removed(next))) |
273399de | 701 | break; |
b453eae1 | 702 | iter_prev = clear_flag(iter); |
273399de MD |
703 | iter = next; |
704 | } | |
705 | assert(!is_removed(iter)); | |
f5596c94 MD |
706 | if (is_dummy(iter)) |
707 | new_next = flag_dummy(clear_flag(next)); | |
708 | else | |
709 | new_next = clear_flag(next); | |
710 | (void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next); | |
273399de MD |
711 | } |
712 | } | |
713 | ||
abc490a1 | 714 | static |
14044b37 MD |
715 | struct cds_lfht_node *_cds_lfht_add(struct cds_lfht *ht, struct rcu_table *t, |
716 | struct cds_lfht_node *node, 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)); | |
18117871 | 725 | if (!t->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 | */ |
24365af7 MD |
738 | index = hash & (t->size - 1); |
739 | order = get_count_order_ulong(index + 1); | |
554c284e | 740 | lookup = &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)) | |
11519af6 MD |
764 | check_resize(ht, t, ++chain_len); |
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 */ | |
24365af7 MD |
797 | index = hash & (t->size - 1); |
798 | order = get_count_order_ulong(index + 1); | |
554c284e | 799 | lookup = &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 |
14044b37 | 806 | int _cds_lfht_remove(struct cds_lfht *ht, struct rcu_table *t, |
1475579c | 807 | struct cds_lfht_node *node, int dummy_removal) |
abc490a1 | 808 | { |
14044b37 MD |
809 | struct cds_lfht_node *dummy, *next, *old; |
810 | struct _cds_lfht_node *lookup; | |
abc490a1 | 811 | int flagged = 0; |
24365af7 | 812 | unsigned long hash, index, order; |
5e28c532 | 813 | |
7ec59d3b | 814 | /* logically delete the node */ |
c90201ac MD |
815 | assert(!is_dummy(node)); |
816 | assert(!is_removed(node)); | |
cc4fcb10 | 817 | old = rcu_dereference(node->p.next); |
7ec59d3b MD |
818 | do { |
819 | next = old; | |
76412f24 | 820 | if (unlikely(is_removed(next))) |
7ec59d3b | 821 | goto end; |
1475579c MD |
822 | if (dummy_removal) |
823 | assert(is_dummy(next)); | |
824 | else | |
825 | assert(!is_dummy(next)); | |
cc4fcb10 | 826 | old = uatomic_cmpxchg(&node->p.next, next, |
7ec59d3b MD |
827 | flag_removed(next)); |
828 | } while (old != next); | |
829 | ||
830 | /* We performed the (logical) deletion. */ | |
831 | flagged = 1; | |
832 | ||
833 | /* | |
834 | * Ensure that the node is not visible to readers anymore: lookup for | |
273399de MD |
835 | * the node, and remove it (along with any other logically removed node) |
836 | * if found. | |
11519af6 | 837 | */ |
cc4fcb10 | 838 | hash = bit_reverse_ulong(node->p.reverse_hash); |
4c3a0329 MD |
839 | assert(t->size > 0); |
840 | index = hash & (t->size - 1); | |
24365af7 | 841 | order = get_count_order_ulong(index + 1); |
554c284e | 842 | lookup = &t->tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1)) - 1))]; |
14044b37 MD |
843 | dummy = (struct cds_lfht_node *) lookup; |
844 | _cds_lfht_gc_bucket(dummy, node); | |
2ed95849 | 845 | end: |
11519af6 MD |
846 | /* |
847 | * Only the flagging action indicated that we (and no other) | |
848 | * removed the node from the hash. | |
849 | */ | |
7ec59d3b | 850 | if (flagged) { |
cc4fcb10 | 851 | assert(is_removed(rcu_dereference(node->p.next))); |
11519af6 | 852 | return 0; |
7ec59d3b | 853 | } else |
11519af6 | 854 | return -ENOENT; |
abc490a1 | 855 | } |
2ed95849 | 856 | |
01dbfa62 MD |
857 | /* |
858 | * Holding RCU read lock to protect _cds_lfht_add against memory | |
859 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
860 | * problem). | |
861 | */ | |
abc490a1 | 862 | static |
14044b37 | 863 | void init_table(struct cds_lfht *ht, struct rcu_table *t, |
24365af7 MD |
864 | unsigned long first_order, unsigned long len_order) |
865 | { | |
866 | unsigned long i, end_order; | |
867 | ||
f0c29ed7 | 868 | dbg_printf("init table: first_order %lu end_order %lu\n", |
24365af7 MD |
869 | first_order, first_order + len_order); |
870 | end_order = first_order + len_order; | |
871 | t->size = !first_order ? 0 : (1UL << (first_order - 1)); | |
872 | for (i = first_order; i < end_order; i++) { | |
873 | unsigned long j, len; | |
874 | ||
875 | len = !i ? 1 : 1UL << (i - 1); | |
f0c29ed7 | 876 | dbg_printf("init order %lu len: %lu\n", i, len); |
1475579c MD |
877 | t->tbl[i] = calloc(1, sizeof(struct rcu_level) |
878 | + (len * sizeof(struct _cds_lfht_node))); | |
01dbfa62 | 879 | ht->cds_lfht_rcu_read_lock(); |
24365af7 | 880 | for (j = 0; j < len; j++) { |
1475579c MD |
881 | struct cds_lfht_node *new_node = |
882 | (struct cds_lfht_node *) &t->tbl[i]->nodes[j]; | |
883 | ||
f0c29ed7 | 884 | dbg_printf("init entry: i %lu j %lu hash %lu\n", |
24365af7 | 885 | i, j, !i ? 0 : (1UL << (i - 1)) + j); |
24365af7 MD |
886 | new_node->p.reverse_hash = |
887 | bit_reverse_ulong(!i ? 0 : (1UL << (i - 1)) + j); | |
14044b37 | 888 | (void) _cds_lfht_add(ht, t, new_node, 0, 1); |
33c7c748 MD |
889 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
890 | break; | |
24365af7 | 891 | } |
01dbfa62 | 892 | ht->cds_lfht_rcu_read_unlock(); |
24365af7 MD |
893 | /* Update table size */ |
894 | t->size = !i ? 1 : (1UL << i); | |
f0c29ed7 | 895 | dbg_printf("init new size: %lu\n", t->size); |
33c7c748 MD |
896 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
897 | break; | |
abc490a1 | 898 | } |
24365af7 | 899 | t->resize_target = t->size; |
11519af6 | 900 | t->resize_initiated = 0; |
2ed95849 MD |
901 | } |
902 | ||
01dbfa62 MD |
903 | /* |
904 | * Holding RCU read lock to protect _cds_lfht_remove against memory | |
905 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
906 | * problem). | |
907 | */ | |
1475579c MD |
908 | static |
909 | void fini_table(struct cds_lfht *ht, struct rcu_table *t, | |
910 | unsigned long first_order, unsigned long len_order) | |
911 | { | |
912 | long i, end_order; | |
913 | ||
914 | dbg_printf("fini table: first_order %lu end_order %lu\n", | |
915 | first_order, first_order + len_order); | |
916 | end_order = first_order + len_order; | |
917 | assert(first_order > 0); | |
918 | assert(t->size == (1UL << (end_order - 1))); | |
919 | for (i = end_order - 1; i >= first_order; i--) { | |
920 | unsigned long j, len; | |
921 | ||
922 | len = !i ? 1 : 1UL << (i - 1); | |
923 | dbg_printf("fini order %lu len: %lu\n", i, len); | |
21263e21 MD |
924 | /* |
925 | * Update table size. Need to shrink this table prior to | |
926 | * removal so gc lookups use non-logically-removed dummy | |
927 | * nodes. | |
928 | */ | |
e1a68f1d | 929 | t->size = 1UL << (i - 1); |
1475579c | 930 | /* Unlink */ |
01dbfa62 | 931 | ht->cds_lfht_rcu_read_lock(); |
1475579c | 932 | for (j = 0; j < len; j++) { |
c90201ac | 933 | struct cds_lfht_node *fini_node = |
1475579c MD |
934 | (struct cds_lfht_node *) &t->tbl[i]->nodes[j]; |
935 | ||
936 | dbg_printf("fini entry: i %lu j %lu hash %lu\n", | |
937 | i, j, !i ? 0 : (1UL << (i - 1)) + j); | |
c90201ac | 938 | fini_node->p.reverse_hash = |
1475579c | 939 | bit_reverse_ulong(!i ? 0 : (1UL << (i - 1)) + j); |
c90201ac | 940 | (void) _cds_lfht_remove(ht, t, fini_node, 1); |
1475579c MD |
941 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
942 | break; | |
943 | } | |
01dbfa62 | 944 | ht->cds_lfht_rcu_read_unlock(); |
1475579c | 945 | ht->cds_lfht_call_rcu(&t->tbl[i]->head, cds_lfht_free_level); |
1475579c MD |
946 | dbg_printf("fini new size: %lu\n", t->size); |
947 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
948 | break; | |
949 | } | |
950 | t->resize_target = t->size; | |
951 | t->resize_initiated = 0; | |
952 | } | |
953 | ||
14044b37 MD |
954 | struct cds_lfht *cds_lfht_new(cds_lfht_hash_fct hash_fct, |
955 | cds_lfht_compare_fct compare_fct, | |
956 | unsigned long hash_seed, | |
957 | unsigned long init_size, | |
b8af5011 | 958 | int flags, |
14044b37 | 959 | void (*cds_lfht_call_rcu)(struct rcu_head *head, |
1475579c | 960 | void (*func)(struct rcu_head *head)), |
01dbfa62 MD |
961 | void (*cds_lfht_synchronize_rcu)(void), |
962 | void (*cds_lfht_rcu_read_lock)(void), | |
963 | void (*cds_lfht_rcu_read_unlock)(void)) | |
abc490a1 | 964 | { |
14044b37 | 965 | struct cds_lfht *ht; |
24365af7 | 966 | unsigned long order; |
abc490a1 | 967 | |
8129be4e | 968 | /* init_size must be power of two */ |
49619ea0 | 969 | if (init_size && (init_size & (init_size - 1))) |
8129be4e | 970 | return NULL; |
14044b37 | 971 | ht = calloc(1, sizeof(struct cds_lfht)); |
abc490a1 | 972 | ht->hash_fct = hash_fct; |
732ad076 MD |
973 | ht->compare_fct = compare_fct; |
974 | ht->hash_seed = hash_seed; | |
14044b37 | 975 | ht->cds_lfht_call_rcu = cds_lfht_call_rcu; |
1475579c | 976 | ht->cds_lfht_synchronize_rcu = cds_lfht_synchronize_rcu; |
01dbfa62 MD |
977 | ht->cds_lfht_rcu_read_lock = cds_lfht_rcu_read_lock; |
978 | ht->cds_lfht_rcu_read_unlock = cds_lfht_rcu_read_unlock; | |
848d4088 | 979 | ht->in_progress_resize = 0; |
df44348d | 980 | ht->percpu_count = alloc_per_cpu_items_count(); |
abc490a1 MD |
981 | /* this mutex should not nest in read-side C.S. */ |
982 | pthread_mutex_init(&ht->resize_mutex, NULL); | |
cd95516d | 983 | order = get_count_order_ulong(max(init_size, MIN_TABLE_SIZE)) + 1; |
14044b37 | 984 | ht->t = calloc(1, sizeof(struct cds_lfht) |
1475579c | 985 | + (order * sizeof(struct rcu_level *))); |
abc490a1 | 986 | ht->t->size = 0; |
b8af5011 | 987 | ht->flags = flags; |
f000907d | 988 | pthread_mutex_lock(&ht->resize_mutex); |
24365af7 | 989 | init_table(ht, ht->t, 0, order); |
f000907d | 990 | pthread_mutex_unlock(&ht->resize_mutex); |
abc490a1 MD |
991 | return ht; |
992 | } | |
993 | ||
14044b37 | 994 | struct cds_lfht_node *cds_lfht_lookup(struct cds_lfht *ht, void *key, size_t key_len) |
2ed95849 | 995 | { |
395270b6 | 996 | struct rcu_table *t; |
14044b37 MD |
997 | struct cds_lfht_node *node, *next; |
998 | struct _cds_lfht_node *lookup; | |
24365af7 | 999 | unsigned long hash, reverse_hash, index, order; |
2ed95849 | 1000 | |
732ad076 | 1001 | hash = ht->hash_fct(key, key_len, ht->hash_seed); |
abc490a1 | 1002 | reverse_hash = bit_reverse_ulong(hash); |
464a1ec9 | 1003 | |
395270b6 | 1004 | t = rcu_dereference(ht->t); |
24365af7 MD |
1005 | index = hash & (t->size - 1); |
1006 | order = get_count_order_ulong(index + 1); | |
554c284e | 1007 | lookup = &t->tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1))) - 1)]; |
f0c29ed7 | 1008 | dbg_printf("lookup hash %lu index %lu order %lu aridx %lu\n", |
554c284e | 1009 | hash, index, order, index & (!order ? 0 : ((1UL << (order - 1)) - 1))); |
14044b37 | 1010 | node = (struct cds_lfht_node *) lookup; |
2ed95849 | 1011 | for (;;) { |
abc490a1 MD |
1012 | if (unlikely(!node)) |
1013 | break; | |
cc4fcb10 | 1014 | if (unlikely(node->p.reverse_hash > reverse_hash)) { |
abc490a1 MD |
1015 | node = NULL; |
1016 | break; | |
2ed95849 | 1017 | } |
1b81fe1a MD |
1018 | next = rcu_dereference(node->p.next); |
1019 | if (likely(!is_removed(next)) | |
1020 | && !is_dummy(next) | |
49c2e2d6 | 1021 | && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) { |
273399de | 1022 | break; |
2ed95849 | 1023 | } |
1b81fe1a | 1024 | node = clear_flag(next); |
2ed95849 | 1025 | } |
1b81fe1a | 1026 | assert(!node || !is_dummy(rcu_dereference(node->p.next))); |
abc490a1 MD |
1027 | return node; |
1028 | } | |
e0ba718a | 1029 | |
a481e5ff MD |
1030 | struct cds_lfht_node *cds_lfht_next(struct cds_lfht *ht, |
1031 | struct cds_lfht_node *node) | |
1032 | { | |
1033 | struct cds_lfht_node *next; | |
1034 | unsigned long reverse_hash; | |
1035 | void *key; | |
1036 | size_t key_len; | |
1037 | ||
1038 | reverse_hash = node->p.reverse_hash; | |
1039 | key = node->key; | |
1040 | key_len = node->key_len; | |
1041 | next = rcu_dereference(node->p.next); | |
1042 | node = clear_flag(next); | |
1043 | ||
1044 | for (;;) { | |
1045 | if (unlikely(!node)) | |
1046 | break; | |
1047 | if (unlikely(node->p.reverse_hash > reverse_hash)) { | |
1048 | node = NULL; | |
1049 | break; | |
1050 | } | |
1051 | next = rcu_dereference(node->p.next); | |
1052 | if (likely(!is_removed(next)) | |
1053 | && !is_dummy(next) | |
1054 | && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) { | |
1055 | break; | |
1056 | } | |
1057 | node = clear_flag(next); | |
1058 | } | |
1059 | assert(!node || !is_dummy(rcu_dereference(node->p.next))); | |
1060 | return node; | |
1061 | } | |
1062 | ||
14044b37 | 1063 | void cds_lfht_add(struct cds_lfht *ht, struct cds_lfht_node *node) |
abc490a1 MD |
1064 | { |
1065 | struct rcu_table *t; | |
49c2e2d6 | 1066 | unsigned long hash; |
ab7d5fc6 | 1067 | |
49c2e2d6 | 1068 | hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed); |
cc4fcb10 | 1069 | node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash); |
2ed95849 | 1070 | |
abc490a1 | 1071 | t = rcu_dereference(ht->t); |
14044b37 | 1072 | (void) _cds_lfht_add(ht, t, node, 0, 0); |
df44348d | 1073 | ht_count_add(ht, t); |
3eca1b8c MD |
1074 | } |
1075 | ||
14044b37 MD |
1076 | struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, |
1077 | struct cds_lfht_node *node) | |
3eca1b8c MD |
1078 | { |
1079 | struct rcu_table *t; | |
49c2e2d6 | 1080 | unsigned long hash; |
df44348d | 1081 | struct cds_lfht_node *ret; |
3eca1b8c | 1082 | |
49c2e2d6 | 1083 | hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed); |
cc4fcb10 | 1084 | node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash); |
3eca1b8c MD |
1085 | |
1086 | t = rcu_dereference(ht->t); | |
df44348d MD |
1087 | ret = _cds_lfht_add(ht, t, node, 1, 0); |
1088 | if (ret != node) | |
1089 | ht_count_add(ht, t); | |
1090 | return ret; | |
2ed95849 MD |
1091 | } |
1092 | ||
14044b37 | 1093 | int cds_lfht_remove(struct cds_lfht *ht, struct cds_lfht_node *node) |
2ed95849 | 1094 | { |
abc490a1 | 1095 | struct rcu_table *t; |
df44348d | 1096 | int ret; |
abc490a1 MD |
1097 | |
1098 | t = rcu_dereference(ht->t); | |
1475579c | 1099 | ret = _cds_lfht_remove(ht, t, node, 0); |
df44348d MD |
1100 | if (!ret) |
1101 | ht_count_remove(ht, t); | |
1102 | return ret; | |
2ed95849 | 1103 | } |
ab7d5fc6 | 1104 | |
abc490a1 | 1105 | static |
14044b37 | 1106 | int cds_lfht_delete_dummy(struct cds_lfht *ht) |
674f7a69 | 1107 | { |
395270b6 | 1108 | struct rcu_table *t; |
14044b37 MD |
1109 | struct cds_lfht_node *node; |
1110 | struct _cds_lfht_node *lookup; | |
24365af7 | 1111 | unsigned long order, i; |
674f7a69 | 1112 | |
abc490a1 MD |
1113 | t = ht->t; |
1114 | /* Check that the table is empty */ | |
1475579c | 1115 | lookup = &t->tbl[0]->nodes[0]; |
14044b37 | 1116 | node = (struct cds_lfht_node *) lookup; |
abc490a1 | 1117 | do { |
1b81fe1a MD |
1118 | node = clear_flag(node)->p.next; |
1119 | if (!is_dummy(node)) | |
abc490a1 | 1120 | return -EPERM; |
273399de | 1121 | assert(!is_removed(node)); |
a2974903 | 1122 | } while (clear_flag(node)); |
abc490a1 | 1123 | /* Internal sanity check: all nodes left should be dummy */ |
24365af7 MD |
1124 | for (order = 0; order < get_count_order_ulong(t->size) + 1; order++) { |
1125 | unsigned long len; | |
1126 | ||
1127 | len = !order ? 1 : 1UL << (order - 1); | |
1128 | for (i = 0; i < len; i++) { | |
f0c29ed7 | 1129 | dbg_printf("delete order %lu i %lu hash %lu\n", |
24365af7 | 1130 | order, i, |
1475579c MD |
1131 | bit_reverse_ulong(t->tbl[order]->nodes[i].reverse_hash)); |
1132 | assert(is_dummy(t->tbl[order]->nodes[i].next)); | |
24365af7 | 1133 | } |
98808fb1 | 1134 | poison_free(t->tbl[order]); |
674f7a69 | 1135 | } |
abc490a1 | 1136 | return 0; |
674f7a69 MD |
1137 | } |
1138 | ||
1139 | /* | |
1140 | * Should only be called when no more concurrent readers nor writers can | |
1141 | * possibly access the table. | |
1142 | */ | |
14044b37 | 1143 | int cds_lfht_destroy(struct cds_lfht *ht) |
674f7a69 | 1144 | { |
5e28c532 MD |
1145 | int ret; |
1146 | ||
848d4088 | 1147 | /* Wait for in-flight resize operations to complete */ |
33c7c748 | 1148 | CMM_STORE_SHARED(ht->in_progress_destroy, 1); |
848d4088 MD |
1149 | while (uatomic_read(&ht->in_progress_resize)) |
1150 | poll(NULL, 0, 100); /* wait for 100ms */ | |
14044b37 | 1151 | ret = cds_lfht_delete_dummy(ht); |
abc490a1 MD |
1152 | if (ret) |
1153 | return ret; | |
98808fb1 | 1154 | poison_free(ht->t); |
df44348d | 1155 | free_per_cpu_items_count(ht->percpu_count); |
98808fb1 | 1156 | poison_free(ht); |
5e28c532 | 1157 | return ret; |
674f7a69 MD |
1158 | } |
1159 | ||
14044b37 | 1160 | void cds_lfht_count_nodes(struct cds_lfht *ht, |
273399de MD |
1161 | unsigned long *count, |
1162 | unsigned long *removed) | |
1163 | { | |
1164 | struct rcu_table *t; | |
14044b37 MD |
1165 | struct cds_lfht_node *node, *next; |
1166 | struct _cds_lfht_node *lookup; | |
24365af7 | 1167 | unsigned long nr_dummy = 0; |
273399de MD |
1168 | |
1169 | *count = 0; | |
1170 | *removed = 0; | |
1171 | ||
1172 | t = rcu_dereference(ht->t); | |
24365af7 | 1173 | /* Count non-dummy nodes in the table */ |
1475579c | 1174 | lookup = &t->tbl[0]->nodes[0]; |
14044b37 | 1175 | node = (struct cds_lfht_node *) lookup; |
273399de | 1176 | do { |
cc4fcb10 | 1177 | next = rcu_dereference(node->p.next); |
273399de | 1178 | if (is_removed(next)) { |
1b81fe1a | 1179 | assert(!is_dummy(next)); |
273399de | 1180 | (*removed)++; |
1b81fe1a | 1181 | } else if (!is_dummy(next)) |
273399de | 1182 | (*count)++; |
24365af7 MD |
1183 | else |
1184 | (nr_dummy)++; | |
273399de MD |
1185 | node = clear_flag(next); |
1186 | } while (node); | |
f0c29ed7 | 1187 | dbg_printf("number of dummy nodes: %lu\n", nr_dummy); |
273399de MD |
1188 | } |
1189 | ||
1475579c | 1190 | /* called with resize mutex held */ |
abc490a1 | 1191 | static |
1475579c MD |
1192 | void _do_cds_lfht_grow(struct cds_lfht *ht, struct rcu_table *old_t, |
1193 | unsigned long old_size, unsigned long new_size) | |
abc490a1 | 1194 | { |
1475579c MD |
1195 | unsigned long old_order, new_order; |
1196 | struct rcu_table *new_t; | |
1197 | ||
1198 | old_order = get_count_order_ulong(old_size) + 1; | |
1199 | new_order = get_count_order_ulong(new_size) + 1; | |
1200 | printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", | |
1201 | old_size, old_order, new_size, new_order); | |
1202 | new_t = malloc(sizeof(struct cds_lfht) | |
1203 | + (new_order * sizeof(struct rcu_level *))); | |
1204 | assert(new_size > old_size); | |
1205 | memcpy(&new_t->tbl, &old_t->tbl, | |
1206 | old_order * sizeof(struct rcu_level *)); | |
1207 | init_table(ht, new_t, old_order, new_order - old_order); | |
1208 | /* Changing table and size atomically wrt lookups */ | |
1209 | rcu_assign_pointer(ht->t, new_t); | |
1210 | ht->cds_lfht_call_rcu(&old_t->head, cds_lfht_free_table_cb); | |
abc490a1 MD |
1211 | } |
1212 | ||
1213 | /* called with resize mutex held */ | |
1214 | static | |
1475579c MD |
1215 | void _do_cds_lfht_shrink(struct cds_lfht *ht, struct rcu_table *old_t, |
1216 | unsigned long old_size, unsigned long new_size) | |
464a1ec9 | 1217 | { |
1475579c MD |
1218 | unsigned long old_order, new_order; |
1219 | struct rcu_table *new_t; | |
464a1ec9 | 1220 | |
cd95516d | 1221 | new_size = max(new_size, MIN_TABLE_SIZE); |
24365af7 | 1222 | old_order = get_count_order_ulong(old_size) + 1; |
24365af7 | 1223 | new_order = get_count_order_ulong(new_size) + 1; |
df44348d | 1224 | printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", |
df03fab8 | 1225 | old_size, old_order, new_size, new_order); |
14044b37 | 1226 | new_t = malloc(sizeof(struct cds_lfht) |
1475579c MD |
1227 | + (new_order * sizeof(struct rcu_level *))); |
1228 | assert(new_size < old_size); | |
f000907d | 1229 | memcpy(&new_t->tbl, &old_t->tbl, |
1475579c MD |
1230 | new_order * sizeof(struct rcu_level *)); |
1231 | new_t->size = !new_order ? 1 : (1UL << (new_order - 1)); | |
c90201ac | 1232 | assert(new_t->size == new_size); |
1475579c MD |
1233 | new_t->resize_target = new_t->size; |
1234 | new_t->resize_initiated = 0; | |
1235 | ||
f000907d MD |
1236 | /* Changing table and size atomically wrt lookups */ |
1237 | rcu_assign_pointer(ht->t, new_t); | |
1475579c MD |
1238 | |
1239 | /* | |
c90201ac | 1240 | * We need to wait for all add operations to reach Q.S. (and |
1475579c | 1241 | * thus use the new table for lookups) before we can start |
c90201ac MD |
1242 | * releasing the old dummy nodes. Otherwise their lookup will |
1243 | * return a logically removed node as insert position. | |
1475579c MD |
1244 | */ |
1245 | ht->cds_lfht_synchronize_rcu(); | |
1246 | ||
1247 | /* Unlink and remove all now-unused dummy node pointers. */ | |
1248 | fini_table(ht, old_t, new_order, old_order - new_order); | |
14044b37 | 1249 | ht->cds_lfht_call_rcu(&old_t->head, cds_lfht_free_table_cb); |
464a1ec9 MD |
1250 | } |
1251 | ||
1475579c MD |
1252 | |
1253 | /* called with resize mutex held */ | |
1254 | static | |
1255 | void _do_cds_lfht_resize(struct cds_lfht *ht) | |
1256 | { | |
1257 | unsigned long new_size, old_size; | |
1258 | struct rcu_table *old_t; | |
1259 | ||
1260 | old_t = ht->t; | |
1261 | old_size = old_t->size; | |
1262 | new_size = CMM_LOAD_SHARED(old_t->resize_target); | |
1263 | if (old_size < new_size) | |
1264 | _do_cds_lfht_grow(ht, old_t, old_size, new_size); | |
1265 | else if (old_size > new_size) | |
1266 | _do_cds_lfht_shrink(ht, old_t, old_size, new_size); | |
1267 | else | |
1268 | CMM_STORE_SHARED(old_t->resize_initiated, 0); | |
1269 | } | |
1270 | ||
abc490a1 | 1271 | static |
f9830efd MD |
1272 | unsigned long resize_target_update(struct rcu_table *t, |
1273 | int growth_order) | |
464a1ec9 | 1274 | { |
f9830efd MD |
1275 | return _uatomic_max(&t->resize_target, |
1276 | t->size << growth_order); | |
464a1ec9 MD |
1277 | } |
1278 | ||
1475579c | 1279 | static |
b8af5011 MD |
1280 | void resize_target_update_count(struct rcu_table *t, |
1281 | unsigned long count) | |
1475579c | 1282 | { |
cd95516d | 1283 | count = max(count, MIN_TABLE_SIZE); |
b8af5011 | 1284 | uatomic_set(&t->resize_target, count); |
1475579c MD |
1285 | } |
1286 | ||
1287 | void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size) | |
464a1ec9 | 1288 | { |
f9830efd | 1289 | struct rcu_table *t = rcu_dereference(ht->t); |
f9830efd | 1290 | |
b8af5011 | 1291 | resize_target_update_count(t, new_size); |
1475579c MD |
1292 | CMM_STORE_SHARED(t->resize_initiated, 1); |
1293 | pthread_mutex_lock(&ht->resize_mutex); | |
1294 | _do_cds_lfht_resize(ht); | |
1295 | pthread_mutex_unlock(&ht->resize_mutex); | |
abc490a1 | 1296 | } |
464a1ec9 | 1297 | |
abc490a1 MD |
1298 | static |
1299 | void do_resize_cb(struct rcu_head *head) | |
1300 | { | |
1301 | struct rcu_resize_work *work = | |
1302 | caa_container_of(head, struct rcu_resize_work, head); | |
14044b37 | 1303 | struct cds_lfht *ht = work->ht; |
abc490a1 MD |
1304 | |
1305 | pthread_mutex_lock(&ht->resize_mutex); | |
14044b37 | 1306 | _do_cds_lfht_resize(ht); |
abc490a1 | 1307 | pthread_mutex_unlock(&ht->resize_mutex); |
98808fb1 | 1308 | poison_free(work); |
848d4088 MD |
1309 | cmm_smp_mb(); /* finish resize before decrement */ |
1310 | uatomic_dec(&ht->in_progress_resize); | |
464a1ec9 MD |
1311 | } |
1312 | ||
abc490a1 | 1313 | static |
14044b37 | 1314 | void cds_lfht_resize_lazy(struct cds_lfht *ht, struct rcu_table *t, int growth) |
ab7d5fc6 | 1315 | { |
abc490a1 | 1316 | struct rcu_resize_work *work; |
f9830efd | 1317 | unsigned long target_size; |
abc490a1 | 1318 | |
f9830efd | 1319 | target_size = resize_target_update(t, growth); |
11519af6 | 1320 | if (!CMM_LOAD_SHARED(t->resize_initiated) && t->size < target_size) { |
848d4088 MD |
1321 | uatomic_inc(&ht->in_progress_resize); |
1322 | cmm_smp_mb(); /* increment resize count before calling it */ | |
f9830efd MD |
1323 | work = malloc(sizeof(*work)); |
1324 | work->ht = ht; | |
14044b37 | 1325 | ht->cds_lfht_call_rcu(&work->head, do_resize_cb); |
11519af6 | 1326 | CMM_STORE_SHARED(t->resize_initiated, 1); |
f9830efd | 1327 | } |
ab7d5fc6 | 1328 | } |
3171717f | 1329 | |
f8994aee MD |
1330 | #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) |
1331 | ||
3171717f MD |
1332 | static |
1333 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, struct rcu_table *t, | |
1334 | unsigned long count) | |
1335 | { | |
1336 | struct rcu_resize_work *work; | |
3171717f | 1337 | |
b8af5011 MD |
1338 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) |
1339 | return; | |
1340 | resize_target_update_count(t, count); | |
1475579c | 1341 | if (!CMM_LOAD_SHARED(t->resize_initiated)) { |
3171717f MD |
1342 | uatomic_inc(&ht->in_progress_resize); |
1343 | cmm_smp_mb(); /* increment resize count before calling it */ | |
1344 | work = malloc(sizeof(*work)); | |
1345 | work->ht = ht; | |
1346 | ht->cds_lfht_call_rcu(&work->head, do_resize_cb); | |
1347 | CMM_STORE_SHARED(t->resize_initiated, 1); | |
1348 | } | |
1349 | } | |
f8994aee MD |
1350 | |
1351 | #endif |