Commit | Line | Data |
---|---|---|
5e28c532 | 1 | /* |
abc490a1 MD |
2 | * rculfhash.c |
3 | * | |
1475579c | 4 | * Userspace RCU library - Lock-Free Resizable RCU Hash Table |
abc490a1 MD |
5 | * |
6 | * Copyright 2010-2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
7 | * | |
8 | * This library is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU Lesser General Public | |
10 | * License as published by the Free Software Foundation; either | |
11 | * version 2.1 of the License, or (at your option) any later version. | |
12 | * | |
13 | * This library is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | * Lesser General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU Lesser General Public | |
19 | * License along with this library; if not, write to the Free Software | |
20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
5e28c532 MD |
21 | */ |
22 | ||
e753ff5a MD |
23 | /* |
24 | * Based on the following articles: | |
25 | * - Ori Shalev and Nir Shavit. Split-ordered lists: Lock-free | |
26 | * extensible hash tables. J. ACM 53, 3 (May 2006), 379-405. | |
27 | * - Michael, M. M. High performance dynamic lock-free hash tables | |
28 | * and list-based sets. In Proceedings of the fourteenth annual ACM | |
29 | * symposium on Parallel algorithms and architectures, ACM Press, | |
30 | * (2002), 73-82. | |
31 | * | |
1475579c | 32 | * Some specificities of this Lock-Free Resizable RCU Hash Table |
e753ff5a MD |
33 | * implementation: |
34 | * | |
35 | * - RCU read-side critical section allows readers to perform hash | |
36 | * table lookups and use the returned objects safely by delaying | |
37 | * memory reclaim of a grace period. | |
38 | * - Add and remove operations are lock-free, and do not need to | |
39 | * allocate memory. They need to be executed within RCU read-side | |
40 | * critical section to ensure the objects they read are valid and to | |
41 | * deal with the cmpxchg ABA problem. | |
42 | * - add and add_unique operations are supported. add_unique checks if | |
43 | * the node key already exists in the hash table. It ensures no key | |
44 | * duplicata exists. | |
45 | * - The resize operation executes concurrently with add/remove/lookup. | |
46 | * - Hash table nodes are contained within a split-ordered list. This | |
47 | * list is ordered by incrementing reversed-bits-hash value. | |
48 | * - An index of dummy nodes is kept. These dummy nodes are the hash | |
49 | * table "buckets", and they are also chained together in the | |
50 | * split-ordered list, which allows recursive expansion. | |
1475579c MD |
51 | * - The resize operation for small tables only allows expanding the hash table. |
52 | * It is triggered automatically by detecting long chains in the add | |
53 | * operation. | |
54 | * - The resize operation for larger tables (and available through an | |
55 | * API) allows both expanding and shrinking the hash table. | |
56 | * - Per-CPU Split-counters are used to keep track of the number of | |
57 | * nodes within the hash table for automatic resize triggering. | |
e753ff5a MD |
58 | * - Resize operation initiated by long chain detection is executed by a |
59 | * call_rcu thread, which keeps lock-freedom of add and remove. | |
60 | * - Resize operations are protected by a mutex. | |
61 | * - The removal operation is split in two parts: first, a "removed" | |
62 | * flag is set in the next pointer within the node to remove. Then, | |
63 | * a "garbage collection" is performed in the bucket containing the | |
64 | * removed node (from the start of the bucket up to the removed node). | |
65 | * All encountered nodes with "removed" flag set in their next | |
66 | * pointers are removed from the linked-list. If the cmpxchg used for | |
67 | * removal fails (due to concurrent garbage-collection or concurrent | |
68 | * add), we retry from the beginning of the bucket. This ensures that | |
69 | * the node with "removed" flag set is removed from the hash table | |
70 | * (not visible to lookups anymore) before the RCU read-side critical | |
71 | * section held across removal ends. Furthermore, this ensures that | |
72 | * the node with "removed" flag set is removed from the linked-list | |
73 | * before its memory is reclaimed. Only the thread which removal | |
74 | * successfully set the "removed" flag (with a cmpxchg) into a node's | |
75 | * next pointer is considered to have succeeded its removal (and thus | |
76 | * owns the node to reclaim). Because we garbage-collect starting from | |
77 | * an invariant node (the start-of-bucket dummy node) up to the | |
78 | * "removed" node (or find a reverse-hash that is higher), we are sure | |
79 | * that a successful traversal of the chain leads to a chain that is | |
80 | * present in the linked-list (the start node is never removed) and | |
81 | * that is does not contain the "removed" node anymore, even if | |
82 | * concurrent delete/add operations are changing the structure of the | |
83 | * list concurrently. | |
29e669f6 MD |
84 | * - The add operation performs gargage collection of buckets if it |
85 | * encounters nodes with removed flag set in the bucket where it wants | |
86 | * to add its new node. This ensures lock-freedom of add operation by | |
87 | * helping the remover unlink nodes from the list rather than to wait | |
88 | * for it do to so. | |
e753ff5a MD |
89 | * - A RCU "order table" indexed by log2(hash index) is copied and |
90 | * expanded by the resize operation. This order table allows finding | |
91 | * the "dummy node" tables. | |
92 | * - There is one dummy node table per hash index order. The size of | |
93 | * each dummy node table is half the number of hashes contained in | |
94 | * this order. | |
95 | * - call_rcu is used to garbage-collect the old order table. | |
96 | * - The per-order dummy node tables contain a compact version of the | |
97 | * hash table nodes. These tables are invariant after they are | |
98 | * populated into the hash table. | |
1475579c MD |
99 | * |
100 | * A bit of ascii art explanation: | |
101 | * | |
102 | * Order index is the off-by-one compare to the actual power of 2 because | |
103 | * we use index 0 to deal with the 0 special-case. | |
104 | * | |
105 | * This shows the nodes for a small table ordered by reversed bits: | |
106 | * | |
107 | * bits reverse | |
108 | * 0 000 000 | |
109 | * 4 100 001 | |
110 | * 2 010 010 | |
111 | * 6 110 011 | |
112 | * 1 001 100 | |
113 | * 5 101 101 | |
114 | * 3 011 110 | |
115 | * 7 111 111 | |
116 | * | |
117 | * This shows the nodes in order of non-reversed bits, linked by | |
118 | * reversed-bit order. | |
119 | * | |
120 | * order bits reverse | |
121 | * 0 0 000 000 | |
122 | * | | |
f6fdd688 MD |
123 | * 1 | 1 001 100 <- <- |
124 | * | | | | | |
125 | * 2 | | 2 010 010 | | | |
126 | * | | | 3 011 110 | <- | | |
127 | * | | | | | | | | |
1475579c MD |
128 | * 3 -> | | | 4 100 001 | | |
129 | * -> | | 5 101 101 | | |
130 | * -> | 6 110 011 | |
131 | * -> 7 111 111 | |
e753ff5a MD |
132 | */ |
133 | ||
2ed95849 MD |
134 | #define _LGPL_SOURCE |
135 | #include <stdlib.h> | |
e0ba718a MD |
136 | #include <errno.h> |
137 | #include <assert.h> | |
138 | #include <stdio.h> | |
abc490a1 | 139 | #include <stdint.h> |
f000907d | 140 | #include <string.h> |
e0ba718a | 141 | |
df44348d | 142 | #include "config.h" |
2ed95849 | 143 | #include <urcu.h> |
abc490a1 | 144 | #include <urcu-call-rcu.h> |
a42cc659 MD |
145 | #include <urcu/arch.h> |
146 | #include <urcu/uatomic.h> | |
674f7a69 | 147 | #include <urcu/jhash.h> |
a42cc659 | 148 | #include <urcu/compiler.h> |
abc490a1 | 149 | #include <urcu/rculfhash.h> |
5e28c532 | 150 | #include <stdio.h> |
464a1ec9 | 151 | #include <pthread.h> |
44395fb7 | 152 | |
f9830efd | 153 | #ifdef DEBUG |
f0c29ed7 | 154 | #define dbg_printf(fmt, args...) printf("[debug rculfhash] " fmt, ## args) |
f9830efd | 155 | #else |
e753ff5a | 156 | #define dbg_printf(fmt, args...) |
f9830efd MD |
157 | #endif |
158 | ||
f8994aee MD |
159 | /* |
160 | * Per-CPU split-counters lazily update the global counter each 1024 | |
161 | * addition/removal. It automatically keeps track of resize required. | |
162 | * We use the bucket length as indicator for need to expand for small | |
163 | * tables and machines lacking per-cpu data suppport. | |
164 | */ | |
165 | #define COUNT_COMMIT_ORDER 10 | |
6ea6bc67 MD |
166 | #define CHAIN_LEN_TARGET 1 |
167 | #define CHAIN_LEN_RESIZE_THRESHOLD 3 | |
2ed95849 | 168 | |
cd95516d | 169 | /* |
76a73da8 | 170 | * Define the minimum table size. |
cd95516d | 171 | */ |
c9edd44a | 172 | #define MIN_TABLE_SIZE 1 |
cd95516d | 173 | |
4105056a MD |
174 | #if (CAA_BITS_PER_LONG == 32) |
175 | #define MAX_TABLE_ORDER 32 | |
176 | #else | |
177 | #define MAX_TABLE_ORDER 64 | |
178 | #endif | |
179 | ||
b7d619b0 MD |
180 | /* |
181 | * Minimum number of dummy nodes to touch per thread to parallelize grow/shrink. | |
182 | */ | |
6083a889 MD |
183 | #define MIN_PARTITION_PER_THREAD_ORDER 12 |
184 | #define MIN_PARTITION_PER_THREAD (1UL << MIN_PARTITION_PER_THREAD_ORDER) | |
b7d619b0 | 185 | |
4105056a MD |
186 | #ifndef min |
187 | #define min(a, b) ((a) < (b) ? (a) : (b)) | |
188 | #endif | |
189 | ||
abc490a1 MD |
190 | #ifndef max |
191 | #define max(a, b) ((a) > (b) ? (a) : (b)) | |
192 | #endif | |
2ed95849 | 193 | |
d95bd160 MD |
194 | /* |
195 | * The removed flag needs to be updated atomically with the pointer. | |
48ed1c18 | 196 | * It indicates that no node must attach to the node scheduled for |
b198f0fd | 197 | * removal, and that node garbage collection must be performed. |
d95bd160 MD |
198 | * The dummy flag does not require to be updated atomically with the |
199 | * pointer, but it is added as a pointer low bit flag to save space. | |
200 | */ | |
d37166c6 | 201 | #define REMOVED_FLAG (1UL << 0) |
b198f0fd MD |
202 | #define DUMMY_FLAG (1UL << 1) |
203 | #define FLAGS_MASK ((1UL << 2) - 1) | |
d37166c6 | 204 | |
bb7b2f26 | 205 | /* Value of the end pointer. Should not interact with flags. */ |
f9c80341 | 206 | #define END_VALUE NULL |
bb7b2f26 | 207 | |
df44348d | 208 | struct ht_items_count { |
860d07e8 | 209 | unsigned long add, del; |
df44348d MD |
210 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
211 | ||
1475579c MD |
212 | struct rcu_level { |
213 | struct rcu_head head; | |
214 | struct _cds_lfht_node nodes[0]; | |
215 | }; | |
216 | ||
395270b6 | 217 | struct rcu_table { |
4105056a | 218 | unsigned long size; /* always a power of 2, shared (RCU) */ |
f9830efd | 219 | unsigned long resize_target; |
11519af6 | 220 | int resize_initiated; |
4105056a | 221 | struct rcu_level *tbl[MAX_TABLE_ORDER]; |
395270b6 MD |
222 | }; |
223 | ||
14044b37 | 224 | struct cds_lfht { |
4105056a | 225 | struct rcu_table t; |
14044b37 MD |
226 | cds_lfht_hash_fct hash_fct; |
227 | cds_lfht_compare_fct compare_fct; | |
732ad076 | 228 | unsigned long hash_seed; |
b8af5011 | 229 | int flags; |
5f511391 MD |
230 | /* |
231 | * We need to put the work threads offline (QSBR) when taking this | |
232 | * mutex, because we use synchronize_rcu within this mutex critical | |
233 | * section, which waits on read-side critical sections, and could | |
234 | * therefore cause grace-period deadlock if we hold off RCU G.P. | |
235 | * completion. | |
236 | */ | |
464a1ec9 | 237 | pthread_mutex_t resize_mutex; /* resize mutex: add/del mutex */ |
33c7c748 | 238 | unsigned int in_progress_resize, in_progress_destroy; |
14044b37 | 239 | void (*cds_lfht_call_rcu)(struct rcu_head *head, |
abc490a1 | 240 | void (*func)(struct rcu_head *head)); |
1475579c | 241 | void (*cds_lfht_synchronize_rcu)(void); |
01dbfa62 MD |
242 | void (*cds_lfht_rcu_read_lock)(void); |
243 | void (*cds_lfht_rcu_read_unlock)(void); | |
5f511391 MD |
244 | void (*cds_lfht_rcu_thread_offline)(void); |
245 | void (*cds_lfht_rcu_thread_online)(void); | |
b7d619b0 MD |
246 | void (*cds_lfht_rcu_register_thread)(void); |
247 | void (*cds_lfht_rcu_unregister_thread)(void); | |
248 | pthread_attr_t *resize_attr; /* Resize threads attributes */ | |
df44348d MD |
249 | unsigned long count; /* global approximate item count */ |
250 | struct ht_items_count *percpu_count; /* per-cpu item count */ | |
2ed95849 MD |
251 | }; |
252 | ||
abc490a1 MD |
253 | struct rcu_resize_work { |
254 | struct rcu_head head; | |
14044b37 | 255 | struct cds_lfht *ht; |
abc490a1 | 256 | }; |
2ed95849 | 257 | |
b7d619b0 MD |
258 | struct partition_resize_work { |
259 | struct rcu_head head; | |
260 | struct cds_lfht *ht; | |
261 | unsigned long i, start, len; | |
262 | void (*fct)(struct cds_lfht *ht, unsigned long i, | |
263 | unsigned long start, unsigned long len); | |
264 | }; | |
265 | ||
48ed1c18 MD |
266 | enum add_mode { |
267 | ADD_DEFAULT = 0, | |
268 | ADD_UNIQUE = 1, | |
269 | ADD_REPLACE = 2, | |
270 | }; | |
271 | ||
76a73da8 MD |
272 | static |
273 | struct cds_lfht_node *_cds_lfht_add(struct cds_lfht *ht, | |
274 | unsigned long size, | |
275 | struct cds_lfht_node *node, | |
48ed1c18 MD |
276 | enum add_mode mode, int dummy); |
277 | ||
abc490a1 MD |
278 | /* |
279 | * Algorithm to reverse bits in a word by lookup table, extended to | |
280 | * 64-bit words. | |
f9830efd | 281 | * Source: |
abc490a1 | 282 | * http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable |
f9830efd | 283 | * Originally from Public Domain. |
abc490a1 MD |
284 | */ |
285 | ||
286 | static const uint8_t BitReverseTable256[256] = | |
2ed95849 | 287 | { |
abc490a1 MD |
288 | #define R2(n) (n), (n) + 2*64, (n) + 1*64, (n) + 3*64 |
289 | #define R4(n) R2(n), R2((n) + 2*16), R2((n) + 1*16), R2((n) + 3*16) | |
290 | #define R6(n) R4(n), R4((n) + 2*4 ), R4((n) + 1*4 ), R4((n) + 3*4 ) | |
291 | R6(0), R6(2), R6(1), R6(3) | |
292 | }; | |
293 | #undef R2 | |
294 | #undef R4 | |
295 | #undef R6 | |
2ed95849 | 296 | |
abc490a1 MD |
297 | static |
298 | uint8_t bit_reverse_u8(uint8_t v) | |
299 | { | |
300 | return BitReverseTable256[v]; | |
301 | } | |
ab7d5fc6 | 302 | |
abc490a1 MD |
303 | static __attribute__((unused)) |
304 | uint32_t bit_reverse_u32(uint32_t v) | |
305 | { | |
306 | return ((uint32_t) bit_reverse_u8(v) << 24) | | |
307 | ((uint32_t) bit_reverse_u8(v >> 8) << 16) | | |
308 | ((uint32_t) bit_reverse_u8(v >> 16) << 8) | | |
309 | ((uint32_t) bit_reverse_u8(v >> 24)); | |
2ed95849 MD |
310 | } |
311 | ||
abc490a1 MD |
312 | static __attribute__((unused)) |
313 | uint64_t bit_reverse_u64(uint64_t v) | |
2ed95849 | 314 | { |
abc490a1 MD |
315 | return ((uint64_t) bit_reverse_u8(v) << 56) | |
316 | ((uint64_t) bit_reverse_u8(v >> 8) << 48) | | |
317 | ((uint64_t) bit_reverse_u8(v >> 16) << 40) | | |
318 | ((uint64_t) bit_reverse_u8(v >> 24) << 32) | | |
319 | ((uint64_t) bit_reverse_u8(v >> 32) << 24) | | |
320 | ((uint64_t) bit_reverse_u8(v >> 40) << 16) | | |
321 | ((uint64_t) bit_reverse_u8(v >> 48) << 8) | | |
322 | ((uint64_t) bit_reverse_u8(v >> 56)); | |
323 | } | |
324 | ||
325 | static | |
326 | unsigned long bit_reverse_ulong(unsigned long v) | |
327 | { | |
328 | #if (CAA_BITS_PER_LONG == 32) | |
329 | return bit_reverse_u32(v); | |
330 | #else | |
331 | return bit_reverse_u64(v); | |
332 | #endif | |
333 | } | |
334 | ||
f9830efd | 335 | /* |
24365af7 MD |
336 | * fls: returns the position of the most significant bit. |
337 | * Returns 0 if no bit is set, else returns the position of the most | |
338 | * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit). | |
f9830efd | 339 | */ |
24365af7 MD |
340 | #if defined(__i386) || defined(__x86_64) |
341 | static inline | |
342 | unsigned int fls_u32(uint32_t x) | |
f9830efd | 343 | { |
24365af7 MD |
344 | int r; |
345 | ||
346 | asm("bsrl %1,%0\n\t" | |
347 | "jnz 1f\n\t" | |
348 | "movl $-1,%0\n\t" | |
349 | "1:\n\t" | |
350 | : "=r" (r) : "rm" (x)); | |
351 | return r + 1; | |
352 | } | |
353 | #define HAS_FLS_U32 | |
354 | #endif | |
355 | ||
356 | #if defined(__x86_64) | |
357 | static inline | |
358 | unsigned int fls_u64(uint64_t x) | |
359 | { | |
360 | long r; | |
361 | ||
362 | asm("bsrq %1,%0\n\t" | |
363 | "jnz 1f\n\t" | |
364 | "movq $-1,%0\n\t" | |
365 | "1:\n\t" | |
366 | : "=r" (r) : "rm" (x)); | |
367 | return r + 1; | |
368 | } | |
369 | #define HAS_FLS_U64 | |
370 | #endif | |
371 | ||
372 | #ifndef HAS_FLS_U64 | |
373 | static __attribute__((unused)) | |
374 | unsigned int fls_u64(uint64_t x) | |
375 | { | |
376 | unsigned int r = 64; | |
377 | ||
378 | if (!x) | |
379 | return 0; | |
380 | ||
381 | if (!(x & 0xFFFFFFFF00000000ULL)) { | |
382 | x <<= 32; | |
383 | r -= 32; | |
384 | } | |
385 | if (!(x & 0xFFFF000000000000ULL)) { | |
386 | x <<= 16; | |
387 | r -= 16; | |
388 | } | |
389 | if (!(x & 0xFF00000000000000ULL)) { | |
390 | x <<= 8; | |
391 | r -= 8; | |
392 | } | |
393 | if (!(x & 0xF000000000000000ULL)) { | |
394 | x <<= 4; | |
395 | r -= 4; | |
396 | } | |
397 | if (!(x & 0xC000000000000000ULL)) { | |
398 | x <<= 2; | |
399 | r -= 2; | |
400 | } | |
401 | if (!(x & 0x8000000000000000ULL)) { | |
402 | x <<= 1; | |
403 | r -= 1; | |
404 | } | |
405 | return r; | |
406 | } | |
407 | #endif | |
408 | ||
409 | #ifndef HAS_FLS_U32 | |
410 | static __attribute__((unused)) | |
411 | unsigned int fls_u32(uint32_t x) | |
412 | { | |
413 | unsigned int r = 32; | |
f9830efd | 414 | |
24365af7 MD |
415 | if (!x) |
416 | return 0; | |
417 | if (!(x & 0xFFFF0000U)) { | |
418 | x <<= 16; | |
419 | r -= 16; | |
420 | } | |
421 | if (!(x & 0xFF000000U)) { | |
422 | x <<= 8; | |
423 | r -= 8; | |
424 | } | |
425 | if (!(x & 0xF0000000U)) { | |
426 | x <<= 4; | |
427 | r -= 4; | |
428 | } | |
429 | if (!(x & 0xC0000000U)) { | |
430 | x <<= 2; | |
431 | r -= 2; | |
432 | } | |
433 | if (!(x & 0x80000000U)) { | |
434 | x <<= 1; | |
435 | r -= 1; | |
436 | } | |
437 | return r; | |
438 | } | |
439 | #endif | |
440 | ||
441 | unsigned int fls_ulong(unsigned long x) | |
f9830efd | 442 | { |
24365af7 MD |
443 | #if (CAA_BITS_PER_lONG == 32) |
444 | return fls_u32(x); | |
445 | #else | |
446 | return fls_u64(x); | |
447 | #endif | |
448 | } | |
f9830efd | 449 | |
24365af7 MD |
450 | int get_count_order_u32(uint32_t x) |
451 | { | |
452 | int order; | |
453 | ||
454 | order = fls_u32(x) - 1; | |
455 | if (x & (x - 1)) | |
456 | order++; | |
457 | return order; | |
458 | } | |
459 | ||
460 | int get_count_order_ulong(unsigned long x) | |
461 | { | |
462 | int order; | |
463 | ||
464 | order = fls_ulong(x) - 1; | |
465 | if (x & (x - 1)) | |
466 | order++; | |
467 | return order; | |
f9830efd MD |
468 | } |
469 | ||
98808fb1 MD |
470 | #ifdef POISON_FREE |
471 | #define poison_free(ptr) \ | |
472 | do { \ | |
473 | memset(ptr, 0x42, sizeof(*(ptr))); \ | |
474 | free(ptr); \ | |
475 | } while (0) | |
476 | #else | |
477 | #define poison_free(ptr) free(ptr) | |
478 | #endif | |
479 | ||
f9830efd | 480 | static |
4105056a | 481 | void cds_lfht_resize_lazy(struct cds_lfht *ht, unsigned long size, int growth); |
f9830efd | 482 | |
df44348d MD |
483 | /* |
484 | * If the sched_getcpu() and sysconf(_SC_NPROCESSORS_CONF) calls are | |
485 | * available, then we support hash table item accounting. | |
486 | * In the unfortunate event the number of CPUs reported would be | |
487 | * inaccurate, we use modulo arithmetic on the number of CPUs we got. | |
488 | */ | |
df44348d MD |
489 | #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) |
490 | ||
f8994aee | 491 | static |
4105056a | 492 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, |
f8994aee MD |
493 | unsigned long count); |
494 | ||
df44348d MD |
495 | static long nr_cpus_mask = -1; |
496 | ||
497 | static | |
498 | struct ht_items_count *alloc_per_cpu_items_count(void) | |
499 | { | |
500 | struct ht_items_count *count; | |
501 | ||
502 | switch (nr_cpus_mask) { | |
503 | case -2: | |
504 | return NULL; | |
505 | case -1: | |
506 | { | |
507 | long maxcpus; | |
508 | ||
509 | maxcpus = sysconf(_SC_NPROCESSORS_CONF); | |
510 | if (maxcpus <= 0) { | |
511 | nr_cpus_mask = -2; | |
512 | return NULL; | |
513 | } | |
514 | /* | |
515 | * round up number of CPUs to next power of two, so we | |
516 | * can use & for modulo. | |
517 | */ | |
518 | maxcpus = 1UL << get_count_order_ulong(maxcpus); | |
519 | nr_cpus_mask = maxcpus - 1; | |
520 | } | |
521 | /* Fall-through */ | |
522 | default: | |
523 | return calloc(nr_cpus_mask + 1, sizeof(*count)); | |
524 | } | |
525 | } | |
526 | ||
527 | static | |
528 | void free_per_cpu_items_count(struct ht_items_count *count) | |
529 | { | |
98808fb1 | 530 | poison_free(count); |
df44348d MD |
531 | } |
532 | ||
533 | static | |
534 | int ht_get_cpu(void) | |
535 | { | |
536 | int cpu; | |
537 | ||
538 | assert(nr_cpus_mask >= 0); | |
539 | cpu = sched_getcpu(); | |
540 | if (unlikely(cpu < 0)) | |
541 | return cpu; | |
542 | else | |
543 | return cpu & nr_cpus_mask; | |
544 | } | |
545 | ||
546 | static | |
4105056a | 547 | void ht_count_add(struct cds_lfht *ht, unsigned long size) |
df44348d | 548 | { |
3171717f | 549 | unsigned long percpu_count; |
df44348d MD |
550 | int cpu; |
551 | ||
552 | if (unlikely(!ht->percpu_count)) | |
3171717f | 553 | return; |
df44348d MD |
554 | cpu = ht_get_cpu(); |
555 | if (unlikely(cpu < 0)) | |
3171717f MD |
556 | return; |
557 | percpu_count = uatomic_add_return(&ht->percpu_count[cpu].add, 1); | |
df44348d MD |
558 | if (unlikely(!(percpu_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) { |
559 | unsigned long count; | |
560 | ||
561 | dbg_printf("add percpu %lu\n", percpu_count); | |
562 | count = uatomic_add_return(&ht->count, | |
563 | 1UL << COUNT_COMMIT_ORDER); | |
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("add 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 | static | |
860d07e8 | 576 | void ht_count_del(struct cds_lfht *ht, unsigned long size) |
df44348d MD |
577 | { |
578 | unsigned long percpu_count; | |
3171717f | 579 | int cpu; |
df44348d | 580 | |
3171717f MD |
581 | if (unlikely(!ht->percpu_count)) |
582 | return; | |
583 | cpu = ht_get_cpu(); | |
584 | if (unlikely(cpu < 0)) | |
585 | return; | |
80d90c06 | 586 | percpu_count = uatomic_add_return(&ht->percpu_count[cpu].del, 1); |
df44348d MD |
587 | if (unlikely(!(percpu_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) { |
588 | unsigned long count; | |
589 | ||
860d07e8 | 590 | dbg_printf("del percpu %lu\n", percpu_count); |
df44348d | 591 | count = uatomic_add_return(&ht->count, |
3171717f | 592 | -(1UL << COUNT_COMMIT_ORDER)); |
df44348d MD |
593 | /* If power of 2 */ |
594 | if (!(count & (count - 1))) { | |
4105056a | 595 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) >= size) |
f8994aee | 596 | return; |
860d07e8 | 597 | dbg_printf("del set global %lu\n", count); |
4105056a | 598 | cds_lfht_resize_lazy_count(ht, size, |
6ea6bc67 | 599 | count >> (CHAIN_LEN_TARGET - 1)); |
df44348d MD |
600 | } |
601 | } | |
602 | } | |
603 | ||
604 | #else /* #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */ | |
605 | ||
606 | static const long nr_cpus_mask = -1; | |
607 | ||
608 | static | |
609 | struct ht_items_count *alloc_per_cpu_items_count(void) | |
610 | { | |
611 | return NULL; | |
612 | } | |
613 | ||
614 | static | |
615 | void free_per_cpu_items_count(struct ht_items_count *count) | |
616 | { | |
617 | } | |
618 | ||
619 | static | |
4105056a | 620 | void ht_count_add(struct cds_lfht *ht, unsigned long size) |
df44348d MD |
621 | { |
622 | } | |
623 | ||
624 | static | |
860d07e8 | 625 | void ht_count_del(struct cds_lfht *ht, unsigned long size) |
df44348d MD |
626 | { |
627 | } | |
628 | ||
629 | #endif /* #else #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */ | |
630 | ||
631 | ||
f9830efd | 632 | static |
4105056a | 633 | void check_resize(struct cds_lfht *ht, unsigned long size, uint32_t chain_len) |
f9830efd | 634 | { |
f8994aee MD |
635 | unsigned long count; |
636 | ||
b8af5011 MD |
637 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) |
638 | return; | |
f8994aee MD |
639 | count = uatomic_read(&ht->count); |
640 | /* | |
641 | * Use bucket-local length for small table expand and for | |
642 | * environments lacking per-cpu data support. | |
643 | */ | |
644 | if (count >= (1UL << COUNT_COMMIT_ORDER)) | |
645 | return; | |
24365af7 | 646 | if (chain_len > 100) |
f0c29ed7 | 647 | dbg_printf("WARNING: large chain length: %u.\n", |
24365af7 | 648 | chain_len); |
3390d470 | 649 | if (chain_len >= CHAIN_LEN_RESIZE_THRESHOLD) |
4105056a | 650 | cds_lfht_resize_lazy(ht, size, |
01370f0b | 651 | get_count_order_u32(chain_len - (CHAIN_LEN_TARGET - 1))); |
f9830efd MD |
652 | } |
653 | ||
abc490a1 | 654 | static |
14044b37 | 655 | struct cds_lfht_node *clear_flag(struct cds_lfht_node *node) |
abc490a1 | 656 | { |
14044b37 | 657 | return (struct cds_lfht_node *) (((unsigned long) node) & ~FLAGS_MASK); |
abc490a1 MD |
658 | } |
659 | ||
660 | static | |
14044b37 | 661 | int is_removed(struct cds_lfht_node *node) |
abc490a1 | 662 | { |
d37166c6 | 663 | return ((unsigned long) node) & REMOVED_FLAG; |
abc490a1 MD |
664 | } |
665 | ||
666 | static | |
14044b37 | 667 | struct cds_lfht_node *flag_removed(struct cds_lfht_node *node) |
abc490a1 | 668 | { |
14044b37 | 669 | return (struct cds_lfht_node *) (((unsigned long) node) | REMOVED_FLAG); |
abc490a1 MD |
670 | } |
671 | ||
f5596c94 | 672 | static |
14044b37 | 673 | int is_dummy(struct cds_lfht_node *node) |
f5596c94 MD |
674 | { |
675 | return ((unsigned long) node) & DUMMY_FLAG; | |
676 | } | |
677 | ||
678 | static | |
14044b37 | 679 | struct cds_lfht_node *flag_dummy(struct cds_lfht_node *node) |
f5596c94 | 680 | { |
14044b37 | 681 | return (struct cds_lfht_node *) (((unsigned long) node) | DUMMY_FLAG); |
f5596c94 | 682 | } |
bb7b2f26 MD |
683 | |
684 | static | |
685 | struct cds_lfht_node *get_end(void) | |
686 | { | |
687 | return (struct cds_lfht_node *) END_VALUE; | |
688 | } | |
689 | ||
690 | static | |
691 | int is_end(struct cds_lfht_node *node) | |
692 | { | |
693 | return clear_flag(node) == (struct cds_lfht_node *) END_VALUE; | |
694 | } | |
695 | ||
abc490a1 | 696 | static |
f9830efd | 697 | unsigned long _uatomic_max(unsigned long *ptr, unsigned long v) |
abc490a1 MD |
698 | { |
699 | unsigned long old1, old2; | |
700 | ||
701 | old1 = uatomic_read(ptr); | |
702 | do { | |
703 | old2 = old1; | |
704 | if (old2 >= v) | |
f9830efd | 705 | return old2; |
abc490a1 | 706 | } while ((old1 = uatomic_cmpxchg(ptr, old2, v)) != old2); |
f9830efd | 707 | return v; |
abc490a1 MD |
708 | } |
709 | ||
1475579c MD |
710 | static |
711 | void cds_lfht_free_level(struct rcu_head *head) | |
712 | { | |
713 | struct rcu_level *l = | |
714 | caa_container_of(head, struct rcu_level, head); | |
98808fb1 | 715 | poison_free(l); |
1475579c MD |
716 | } |
717 | ||
273399de MD |
718 | /* |
719 | * Remove all logically deleted nodes from a bucket up to a certain node key. | |
720 | */ | |
721 | static | |
f9c80341 | 722 | void _cds_lfht_gc_bucket(struct cds_lfht_node *dummy, struct cds_lfht_node *node) |
273399de | 723 | { |
14044b37 | 724 | struct cds_lfht_node *iter_prev, *iter, *next, *new_next; |
273399de | 725 | |
c90201ac MD |
726 | assert(!is_dummy(dummy)); |
727 | assert(!is_removed(dummy)); | |
728 | assert(!is_dummy(node)); | |
729 | assert(!is_removed(node)); | |
273399de MD |
730 | for (;;) { |
731 | iter_prev = dummy; | |
732 | /* We can always skip the dummy node initially */ | |
cc4fcb10 MD |
733 | iter = rcu_dereference(iter_prev->p.next); |
734 | assert(iter_prev->p.reverse_hash <= node->p.reverse_hash); | |
bd4db153 MD |
735 | /* |
736 | * We should never be called with dummy (start of chain) | |
737 | * and logically removed node (end of path compression | |
738 | * marker) being the actual same node. This would be a | |
739 | * bug in the algorithm implementation. | |
740 | */ | |
741 | assert(dummy != node); | |
273399de | 742 | for (;;) { |
bb7b2f26 | 743 | if (unlikely(is_end(iter))) |
f9c80341 | 744 | return; |
76412f24 | 745 | if (likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash)) |
f9c80341 | 746 | return; |
cc4fcb10 | 747 | next = rcu_dereference(clear_flag(iter)->p.next); |
b198f0fd | 748 | if (likely(is_removed(next))) |
273399de | 749 | break; |
b453eae1 | 750 | iter_prev = clear_flag(iter); |
273399de MD |
751 | iter = next; |
752 | } | |
b198f0fd | 753 | assert(!is_removed(iter)); |
f5596c94 MD |
754 | if (is_dummy(iter)) |
755 | new_next = flag_dummy(clear_flag(next)); | |
756 | else | |
757 | new_next = clear_flag(next); | |
48ed1c18 MD |
758 | if (is_removed(iter)) |
759 | new_next = flag_removed(new_next); | |
f5596c94 | 760 | (void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next); |
273399de | 761 | } |
f9c80341 | 762 | return; |
273399de MD |
763 | } |
764 | ||
abc490a1 | 765 | static |
4105056a MD |
766 | struct cds_lfht_node *_cds_lfht_add(struct cds_lfht *ht, |
767 | unsigned long size, | |
768 | struct cds_lfht_node *node, | |
48ed1c18 | 769 | enum add_mode mode, int dummy) |
abc490a1 | 770 | { |
14044b37 | 771 | struct cds_lfht_node *iter_prev, *iter, *next, *new_node, *new_next, |
adc0de68 | 772 | *dummy_node, *return_node; |
14044b37 | 773 | struct _cds_lfht_node *lookup; |
24365af7 | 774 | unsigned long hash, index, order; |
abc490a1 | 775 | |
c90201ac MD |
776 | assert(!is_dummy(node)); |
777 | assert(!is_removed(node)); | |
4105056a | 778 | if (!size) { |
f5596c94 | 779 | assert(dummy); |
bb7b2f26 | 780 | node->p.next = flag_dummy(get_end()); |
18117871 MD |
781 | return node; /* Initial first add (head) */ |
782 | } | |
cc4fcb10 | 783 | hash = bit_reverse_ulong(node->p.reverse_hash); |
abc490a1 | 784 | for (;;) { |
adc0de68 | 785 | uint32_t chain_len = 0; |
abc490a1 | 786 | |
11519af6 MD |
787 | /* |
788 | * iter_prev points to the non-removed node prior to the | |
789 | * insert location. | |
11519af6 | 790 | */ |
4105056a | 791 | index = hash & (size - 1); |
24365af7 | 792 | order = get_count_order_ulong(index + 1); |
4105056a | 793 | lookup = &ht->t.tbl[order]->nodes[index & ((!order ? 0 : (1UL << (order - 1))) - 1)]; |
14044b37 | 794 | iter_prev = (struct cds_lfht_node *) lookup; |
11519af6 | 795 | /* We can always skip the dummy node initially */ |
cc4fcb10 MD |
796 | iter = rcu_dereference(iter_prev->p.next); |
797 | assert(iter_prev->p.reverse_hash <= node->p.reverse_hash); | |
abc490a1 | 798 | for (;;) { |
bb7b2f26 | 799 | if (unlikely(is_end(iter))) |
273399de | 800 | goto insert; |
76412f24 | 801 | if (likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash)) |
273399de | 802 | goto insert; |
cc4fcb10 | 803 | next = rcu_dereference(clear_flag(iter)->p.next); |
b198f0fd | 804 | if (unlikely(is_removed(next))) |
9dba85be | 805 | goto gc_node; |
48ed1c18 | 806 | if ((mode == ADD_UNIQUE || mode == ADD_REPLACE) |
1b81fe1a | 807 | && !is_dummy(next) |
e43f23f8 MD |
808 | && !ht->compare_fct(node->key, node->key_len, |
809 | clear_flag(iter)->key, | |
48ed1c18 MD |
810 | clear_flag(iter)->key_len)) { |
811 | if (mode == ADD_UNIQUE) | |
812 | return clear_flag(iter); | |
813 | else /* mode == ADD_REPLACE */ | |
814 | goto replace; | |
815 | } | |
11519af6 | 816 | /* Only account for identical reverse hash once */ |
24365af7 MD |
817 | if (iter_prev->p.reverse_hash != clear_flag(iter)->p.reverse_hash |
818 | && !is_dummy(next)) | |
4105056a | 819 | check_resize(ht, size, ++chain_len); |
11519af6 | 820 | iter_prev = clear_flag(iter); |
273399de | 821 | iter = next; |
abc490a1 | 822 | } |
48ed1c18 | 823 | |
273399de | 824 | insert: |
7ec59d3b | 825 | assert(node != clear_flag(iter)); |
11519af6 | 826 | assert(!is_removed(iter_prev)); |
c90201ac | 827 | assert(!is_removed(iter)); |
f000907d | 828 | assert(iter_prev != node); |
f9c80341 | 829 | if (!dummy) |
1b81fe1a | 830 | node->p.next = clear_flag(iter); |
f9c80341 MD |
831 | else |
832 | node->p.next = flag_dummy(clear_flag(iter)); | |
f5596c94 MD |
833 | if (is_dummy(iter)) |
834 | new_node = flag_dummy(node); | |
835 | else | |
836 | new_node = node; | |
cc4fcb10 | 837 | if (uatomic_cmpxchg(&iter_prev->p.next, iter, |
48ed1c18 | 838 | new_node) != iter) { |
273399de | 839 | continue; /* retry */ |
48ed1c18 MD |
840 | } else { |
841 | if (mode == ADD_REPLACE) | |
842 | return_node = NULL; | |
843 | else /* ADD_DEFAULT and ADD_UNIQUE */ | |
844 | return_node = node; | |
273399de | 845 | goto gc_end; |
48ed1c18 MD |
846 | } |
847 | ||
848 | replace: | |
adc0de68 MD |
849 | /* Insert after node to be replaced */ |
850 | iter_prev = clear_flag(iter); | |
851 | iter = next; | |
48ed1c18 MD |
852 | assert(node != clear_flag(iter)); |
853 | assert(!is_removed(iter_prev)); | |
854 | assert(!is_removed(iter)); | |
48ed1c18 MD |
855 | assert(iter_prev != node); |
856 | assert(!dummy); | |
adc0de68 | 857 | node->p.next = clear_flag(iter); |
48ed1c18 MD |
858 | if (is_dummy(iter)) |
859 | new_node = flag_dummy(node); | |
860 | else | |
861 | new_node = node; | |
862 | /* | |
adc0de68 MD |
863 | * Here is the whole trick for lock-free replace: we add |
864 | * the replacement node _after_ the node we want to | |
865 | * replace by atomically setting its next pointer at the | |
b198f0fd | 866 | * same time we set its removal flag. Given that |
adc0de68 MD |
867 | * the lookups/get next use an iterator aware of the |
868 | * next pointer, they will either skip the old node due | |
b198f0fd MD |
869 | * to the removal flag and see the new node, or use |
870 | * the old node, but will not see the new one. | |
48ed1c18 | 871 | */ |
adc0de68 | 872 | new_node = flag_removed(new_node); |
adc0de68 MD |
873 | if (uatomic_cmpxchg(&iter_prev->p.next, |
874 | iter, new_node) != iter) { | |
48ed1c18 MD |
875 | continue; /* retry */ |
876 | } else { | |
adc0de68 MD |
877 | return_node = iter_prev; |
878 | goto gc_end; | |
48ed1c18 MD |
879 | } |
880 | ||
9dba85be MD |
881 | gc_node: |
882 | assert(!is_removed(iter)); | |
f5596c94 MD |
883 | if (is_dummy(iter)) |
884 | new_next = flag_dummy(clear_flag(next)); | |
885 | else | |
886 | new_next = clear_flag(next); | |
887 | (void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next); | |
273399de | 888 | /* retry */ |
464a1ec9 | 889 | } |
273399de MD |
890 | gc_end: |
891 | /* Garbage collect logically removed nodes in the bucket */ | |
4105056a | 892 | index = hash & (size - 1); |
24365af7 | 893 | order = get_count_order_ulong(index + 1); |
4105056a | 894 | lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1)) - 1))]; |
14044b37 | 895 | dummy_node = (struct cds_lfht_node *) lookup; |
f9c80341 | 896 | _cds_lfht_gc_bucket(dummy_node, node); |
48ed1c18 | 897 | return return_node; |
abc490a1 | 898 | } |
464a1ec9 | 899 | |
abc490a1 | 900 | static |
860d07e8 | 901 | int _cds_lfht_del(struct cds_lfht *ht, unsigned long size, |
4105056a | 902 | struct cds_lfht_node *node, |
b198f0fd | 903 | int dummy_removal) |
abc490a1 | 904 | { |
14044b37 MD |
905 | struct cds_lfht_node *dummy, *next, *old; |
906 | struct _cds_lfht_node *lookup; | |
abc490a1 | 907 | int flagged = 0; |
24365af7 | 908 | unsigned long hash, index, order; |
5e28c532 | 909 | |
7ec59d3b | 910 | /* logically delete the node */ |
c90201ac MD |
911 | assert(!is_dummy(node)); |
912 | assert(!is_removed(node)); | |
cc4fcb10 | 913 | old = rcu_dereference(node->p.next); |
7ec59d3b | 914 | do { |
48ed1c18 MD |
915 | struct cds_lfht_node *new_next; |
916 | ||
7ec59d3b | 917 | next = old; |
76412f24 | 918 | if (unlikely(is_removed(next))) |
7ec59d3b | 919 | goto end; |
1475579c MD |
920 | if (dummy_removal) |
921 | assert(is_dummy(next)); | |
922 | else | |
923 | assert(!is_dummy(next)); | |
48ed1c18 | 924 | new_next = flag_removed(next); |
48ed1c18 | 925 | old = uatomic_cmpxchg(&node->p.next, next, new_next); |
7ec59d3b MD |
926 | } while (old != next); |
927 | ||
928 | /* We performed the (logical) deletion. */ | |
929 | flagged = 1; | |
930 | ||
931 | /* | |
932 | * Ensure that the node is not visible to readers anymore: lookup for | |
273399de MD |
933 | * the node, and remove it (along with any other logically removed node) |
934 | * if found. | |
11519af6 | 935 | */ |
cc4fcb10 | 936 | hash = bit_reverse_ulong(node->p.reverse_hash); |
4105056a MD |
937 | assert(size > 0); |
938 | index = hash & (size - 1); | |
24365af7 | 939 | order = get_count_order_ulong(index + 1); |
4105056a | 940 | lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1)) - 1))]; |
14044b37 | 941 | dummy = (struct cds_lfht_node *) lookup; |
f9c80341 | 942 | _cds_lfht_gc_bucket(dummy, node); |
2ed95849 | 943 | end: |
11519af6 MD |
944 | /* |
945 | * Only the flagging action indicated that we (and no other) | |
946 | * removed the node from the hash. | |
947 | */ | |
7ec59d3b | 948 | if (flagged) { |
cc4fcb10 | 949 | assert(is_removed(rcu_dereference(node->p.next))); |
11519af6 | 950 | return 0; |
7ec59d3b | 951 | } else |
11519af6 | 952 | return -ENOENT; |
abc490a1 | 953 | } |
2ed95849 | 954 | |
b7d619b0 MD |
955 | static |
956 | void *partition_resize_thread(void *arg) | |
957 | { | |
958 | struct partition_resize_work *work = arg; | |
959 | ||
960 | work->ht->cds_lfht_rcu_register_thread(); | |
961 | work->fct(work->ht, work->i, work->start, work->len); | |
962 | work->ht->cds_lfht_rcu_unregister_thread(); | |
963 | return NULL; | |
964 | } | |
965 | ||
966 | static | |
967 | void partition_resize_helper(struct cds_lfht *ht, unsigned long i, | |
968 | unsigned long len, | |
969 | void (*fct)(struct cds_lfht *ht, unsigned long i, | |
970 | unsigned long start, unsigned long len)) | |
971 | { | |
972 | unsigned long partition_len; | |
973 | struct partition_resize_work *work; | |
6083a889 MD |
974 | int thread, ret; |
975 | unsigned long nr_threads; | |
b7d619b0 MD |
976 | pthread_t *thread_id; |
977 | ||
6083a889 MD |
978 | /* |
979 | * Note: nr_cpus_mask + 1 is always power of 2. | |
980 | * We spawn just the number of threads we need to satisfy the minimum | |
981 | * partition size, up to the number of CPUs in the system. | |
982 | */ | |
983 | nr_threads = min(nr_cpus_mask + 1, | |
984 | len >> MIN_PARTITION_PER_THREAD_ORDER); | |
985 | partition_len = len >> get_count_order_ulong(nr_threads); | |
986 | work = calloc(nr_threads, sizeof(*work)); | |
987 | thread_id = calloc(nr_threads, sizeof(*thread_id)); | |
b7d619b0 | 988 | assert(work); |
6083a889 MD |
989 | for (thread = 0; thread < nr_threads; thread++) { |
990 | work[thread].ht = ht; | |
991 | work[thread].i = i; | |
992 | work[thread].len = partition_len; | |
993 | work[thread].start = thread * partition_len; | |
994 | work[thread].fct = fct; | |
995 | ret = pthread_create(&thread_id[thread], ht->resize_attr, | |
996 | partition_resize_thread, &work[thread]); | |
b7d619b0 MD |
997 | assert(!ret); |
998 | } | |
6083a889 MD |
999 | for (thread = 0; thread < nr_threads; thread++) { |
1000 | ret = pthread_join(thread_id[thread], NULL); | |
b7d619b0 MD |
1001 | assert(!ret); |
1002 | } | |
1003 | free(work); | |
1004 | free(thread_id); | |
1005 | } | |
1006 | ||
e8de508e MD |
1007 | /* |
1008 | * Holding RCU read lock to protect _cds_lfht_add against memory | |
1009 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
1010 | * problem). | |
9ee0fc9a | 1011 | * |
b7d619b0 | 1012 | * When we reach a certain length, we can split this population phase over |
9ee0fc9a MD |
1013 | * many worker threads, based on the number of CPUs available in the system. |
1014 | * This should therefore take care of not having the expand lagging behind too | |
1015 | * many concurrent insertion threads by using the scheduler's ability to | |
1016 | * schedule dummy node population fairly with insertions. | |
e8de508e | 1017 | */ |
4105056a | 1018 | static |
b7d619b0 MD |
1019 | void init_table_populate_partition(struct cds_lfht *ht, unsigned long i, |
1020 | unsigned long start, unsigned long len) | |
4105056a MD |
1021 | { |
1022 | unsigned long j; | |
1023 | ||
1024 | ht->cds_lfht_rcu_read_lock(); | |
b7d619b0 | 1025 | for (j = start; j < start + len; j++) { |
4105056a MD |
1026 | struct cds_lfht_node *new_node = |
1027 | (struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j]; | |
1028 | ||
dc1da8f6 | 1029 | dbg_printf("init populate: i %lu j %lu hash %lu\n", |
4105056a | 1030 | i, j, !i ? 0 : (1UL << (i - 1)) + j); |
dc1da8f6 MD |
1031 | new_node->p.reverse_hash = |
1032 | bit_reverse_ulong(!i ? 0 : (1UL << (i - 1)) + j); | |
4105056a | 1033 | (void) _cds_lfht_add(ht, !i ? 0 : (1UL << (i - 1)), |
48ed1c18 | 1034 | new_node, ADD_DEFAULT, 1); |
4105056a MD |
1035 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
1036 | break; | |
1037 | } | |
1038 | ht->cds_lfht_rcu_read_unlock(); | |
b7d619b0 MD |
1039 | } |
1040 | ||
1041 | static | |
1042 | void init_table_populate(struct cds_lfht *ht, unsigned long i, | |
1043 | unsigned long len) | |
1044 | { | |
1045 | assert(nr_cpus_mask != -1); | |
6083a889 | 1046 | if (nr_cpus_mask < 0 || len < 2 * MIN_PARTITION_PER_THREAD) { |
b7d619b0 MD |
1047 | ht->cds_lfht_rcu_thread_online(); |
1048 | init_table_populate_partition(ht, i, 0, len); | |
1049 | ht->cds_lfht_rcu_thread_offline(); | |
1050 | return; | |
1051 | } | |
1052 | partition_resize_helper(ht, i, len, init_table_populate_partition); | |
4105056a MD |
1053 | } |
1054 | ||
abc490a1 | 1055 | static |
4105056a | 1056 | void init_table(struct cds_lfht *ht, |
24365af7 MD |
1057 | unsigned long first_order, unsigned long len_order) |
1058 | { | |
1059 | unsigned long i, end_order; | |
1060 | ||
f0c29ed7 | 1061 | dbg_printf("init table: first_order %lu end_order %lu\n", |
24365af7 MD |
1062 | first_order, first_order + len_order); |
1063 | end_order = first_order + len_order; | |
24365af7 | 1064 | for (i = first_order; i < end_order; i++) { |
4105056a | 1065 | unsigned long len; |
24365af7 MD |
1066 | |
1067 | len = !i ? 1 : 1UL << (i - 1); | |
f0c29ed7 | 1068 | dbg_printf("init order %lu len: %lu\n", i, len); |
4d676753 MD |
1069 | |
1070 | /* Stop expand if the resize target changes under us */ | |
1071 | if (CMM_LOAD_SHARED(ht->t.resize_target) < (!i ? 1 : (1UL << i))) | |
1072 | break; | |
1073 | ||
4105056a | 1074 | ht->t.tbl[i] = calloc(1, sizeof(struct rcu_level) |
1475579c | 1075 | + (len * sizeof(struct _cds_lfht_node))); |
b7d619b0 | 1076 | assert(ht->t.tbl[i]); |
4105056a | 1077 | |
4105056a | 1078 | /* |
dc1da8f6 MD |
1079 | * Set all dummy nodes reverse hash values for a level and |
1080 | * link all dummy nodes into the table. | |
4105056a | 1081 | */ |
dc1da8f6 | 1082 | init_table_populate(ht, i, len); |
4105056a | 1083 | |
f9c80341 MD |
1084 | /* |
1085 | * Update table size. | |
1086 | */ | |
1087 | cmm_smp_wmb(); /* populate data before RCU size */ | |
1088 | CMM_STORE_SHARED(ht->t.size, !i ? 1 : (1UL << i)); | |
1089 | ||
4105056a MD |
1090 | dbg_printf("init new size: %lu\n", !i ? 1 : (1UL << i)); |
1091 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
1092 | break; | |
1093 | } | |
1094 | } | |
1095 | ||
e8de508e MD |
1096 | /* |
1097 | * Holding RCU read lock to protect _cds_lfht_remove against memory | |
1098 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
1099 | * problem). | |
1100 | * For a single level, we logically remove and garbage collect each node. | |
1101 | * | |
1102 | * As a design choice, we perform logical removal and garbage collection on a | |
1103 | * node-per-node basis to simplify this algorithm. We also assume keeping good | |
1104 | * cache locality of the operation would overweight possible performance gain | |
1105 | * that could be achieved by batching garbage collection for multiple levels. | |
1106 | * However, this would have to be justified by benchmarks. | |
1107 | * | |
1108 | * Concurrent removal and add operations are helping us perform garbage | |
1109 | * collection of logically removed nodes. We guarantee that all logically | |
1110 | * removed nodes have been garbage-collected (unlinked) before call_rcu is | |
1111 | * invoked to free a hole level of dummy nodes (after a grace period). | |
1112 | * | |
1113 | * Logical removal and garbage collection can therefore be done in batch or on a | |
1114 | * node-per-node basis, as long as the guarantee above holds. | |
9ee0fc9a | 1115 | * |
b7d619b0 MD |
1116 | * When we reach a certain length, we can split this removal over many worker |
1117 | * threads, based on the number of CPUs available in the system. This should | |
1118 | * take care of not letting resize process lag behind too many concurrent | |
9ee0fc9a | 1119 | * updater threads actively inserting into the hash table. |
e8de508e | 1120 | */ |
4105056a | 1121 | static |
b7d619b0 MD |
1122 | void remove_table_partition(struct cds_lfht *ht, unsigned long i, |
1123 | unsigned long start, unsigned long len) | |
4105056a MD |
1124 | { |
1125 | unsigned long j; | |
1126 | ||
1127 | ht->cds_lfht_rcu_read_lock(); | |
b7d619b0 | 1128 | for (j = start; j < start + len; j++) { |
4105056a MD |
1129 | struct cds_lfht_node *fini_node = |
1130 | (struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j]; | |
1131 | ||
1132 | dbg_printf("remove entry: i %lu j %lu hash %lu\n", | |
1133 | i, j, !i ? 0 : (1UL << (i - 1)) + j); | |
1134 | fini_node->p.reverse_hash = | |
1135 | bit_reverse_ulong(!i ? 0 : (1UL << (i - 1)) + j); | |
860d07e8 | 1136 | (void) _cds_lfht_del(ht, !i ? 0 : (1UL << (i - 1)), |
b198f0fd | 1137 | fini_node, 1); |
33c7c748 MD |
1138 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
1139 | break; | |
abc490a1 | 1140 | } |
4105056a | 1141 | ht->cds_lfht_rcu_read_unlock(); |
b7d619b0 MD |
1142 | } |
1143 | ||
1144 | static | |
1145 | void remove_table(struct cds_lfht *ht, unsigned long i, unsigned long len) | |
1146 | { | |
1147 | ||
1148 | assert(nr_cpus_mask != -1); | |
6083a889 | 1149 | if (nr_cpus_mask < 0 || len < 2 * MIN_PARTITION_PER_THREAD) { |
b7d619b0 MD |
1150 | ht->cds_lfht_rcu_thread_online(); |
1151 | remove_table_partition(ht, i, 0, len); | |
1152 | ht->cds_lfht_rcu_thread_offline(); | |
1153 | return; | |
1154 | } | |
1155 | partition_resize_helper(ht, i, len, remove_table_partition); | |
2ed95849 MD |
1156 | } |
1157 | ||
1475579c | 1158 | static |
4105056a | 1159 | void fini_table(struct cds_lfht *ht, |
1475579c MD |
1160 | unsigned long first_order, unsigned long len_order) |
1161 | { | |
1162 | long i, end_order; | |
1163 | ||
1164 | dbg_printf("fini table: first_order %lu end_order %lu\n", | |
1165 | first_order, first_order + len_order); | |
1166 | end_order = first_order + len_order; | |
1167 | assert(first_order > 0); | |
1475579c | 1168 | for (i = end_order - 1; i >= first_order; i--) { |
4105056a | 1169 | unsigned long len; |
1475579c MD |
1170 | |
1171 | len = !i ? 1 : 1UL << (i - 1); | |
1172 | dbg_printf("fini order %lu len: %lu\n", i, len); | |
4105056a | 1173 | |
4d676753 MD |
1174 | /* Stop shrink if the resize target changes under us */ |
1175 | if (CMM_LOAD_SHARED(ht->t.resize_target) > (1UL << (i - 1))) | |
1176 | break; | |
1177 | ||
1178 | cmm_smp_wmb(); /* populate data before RCU size */ | |
1179 | CMM_STORE_SHARED(ht->t.size, 1UL << (i - 1)); | |
1180 | ||
1181 | /* | |
1182 | * We need to wait for all add operations to reach Q.S. (and | |
1183 | * thus use the new table for lookups) before we can start | |
1184 | * releasing the old dummy nodes. Otherwise their lookup will | |
1185 | * return a logically removed node as insert position. | |
1186 | */ | |
1187 | ht->cds_lfht_synchronize_rcu(); | |
1188 | ||
21263e21 | 1189 | /* |
4105056a MD |
1190 | * Set "removed" flag in dummy nodes about to be removed. |
1191 | * Unlink all now-logically-removed dummy node pointers. | |
1192 | * Concurrent add/remove operation are helping us doing | |
1193 | * the gc. | |
21263e21 | 1194 | */ |
4105056a MD |
1195 | remove_table(ht, i, len); |
1196 | ||
1197 | ht->cds_lfht_call_rcu(&ht->t.tbl[i]->head, cds_lfht_free_level); | |
1198 | ||
1199 | dbg_printf("fini new size: %lu\n", 1UL << i); | |
1475579c MD |
1200 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
1201 | break; | |
1202 | } | |
1475579c MD |
1203 | } |
1204 | ||
7a9dcf9b | 1205 | struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct, |
14044b37 MD |
1206 | cds_lfht_compare_fct compare_fct, |
1207 | unsigned long hash_seed, | |
1208 | unsigned long init_size, | |
b8af5011 | 1209 | int flags, |
14044b37 | 1210 | void (*cds_lfht_call_rcu)(struct rcu_head *head, |
1475579c | 1211 | void (*func)(struct rcu_head *head)), |
01dbfa62 MD |
1212 | void (*cds_lfht_synchronize_rcu)(void), |
1213 | void (*cds_lfht_rcu_read_lock)(void), | |
5f511391 MD |
1214 | void (*cds_lfht_rcu_read_unlock)(void), |
1215 | void (*cds_lfht_rcu_thread_offline)(void), | |
b7d619b0 MD |
1216 | void (*cds_lfht_rcu_thread_online)(void), |
1217 | void (*cds_lfht_rcu_register_thread)(void), | |
1218 | void (*cds_lfht_rcu_unregister_thread)(void), | |
1219 | pthread_attr_t *attr) | |
abc490a1 | 1220 | { |
14044b37 | 1221 | struct cds_lfht *ht; |
24365af7 | 1222 | unsigned long order; |
abc490a1 | 1223 | |
8129be4e | 1224 | /* init_size must be power of two */ |
49619ea0 | 1225 | if (init_size && (init_size & (init_size - 1))) |
8129be4e | 1226 | return NULL; |
14044b37 | 1227 | ht = calloc(1, sizeof(struct cds_lfht)); |
b7d619b0 | 1228 | assert(ht); |
abc490a1 | 1229 | ht->hash_fct = hash_fct; |
732ad076 MD |
1230 | ht->compare_fct = compare_fct; |
1231 | ht->hash_seed = hash_seed; | |
14044b37 | 1232 | ht->cds_lfht_call_rcu = cds_lfht_call_rcu; |
1475579c | 1233 | ht->cds_lfht_synchronize_rcu = cds_lfht_synchronize_rcu; |
01dbfa62 MD |
1234 | ht->cds_lfht_rcu_read_lock = cds_lfht_rcu_read_lock; |
1235 | ht->cds_lfht_rcu_read_unlock = cds_lfht_rcu_read_unlock; | |
5f511391 MD |
1236 | ht->cds_lfht_rcu_thread_offline = cds_lfht_rcu_thread_offline; |
1237 | ht->cds_lfht_rcu_thread_online = cds_lfht_rcu_thread_online; | |
b7d619b0 MD |
1238 | ht->cds_lfht_rcu_register_thread = cds_lfht_rcu_register_thread; |
1239 | ht->cds_lfht_rcu_unregister_thread = cds_lfht_rcu_unregister_thread; | |
1240 | ht->resize_attr = attr; | |
df44348d | 1241 | ht->percpu_count = alloc_per_cpu_items_count(); |
abc490a1 MD |
1242 | /* this mutex should not nest in read-side C.S. */ |
1243 | pthread_mutex_init(&ht->resize_mutex, NULL); | |
cd95516d | 1244 | order = get_count_order_ulong(max(init_size, MIN_TABLE_SIZE)) + 1; |
b8af5011 | 1245 | ht->flags = flags; |
5f511391 | 1246 | ht->cds_lfht_rcu_thread_offline(); |
f000907d | 1247 | pthread_mutex_lock(&ht->resize_mutex); |
4d676753 | 1248 | ht->t.resize_target = 1UL << (order - 1); |
4105056a | 1249 | init_table(ht, 0, order); |
f000907d | 1250 | pthread_mutex_unlock(&ht->resize_mutex); |
5f511391 | 1251 | ht->cds_lfht_rcu_thread_online(); |
abc490a1 MD |
1252 | return ht; |
1253 | } | |
1254 | ||
adc0de68 MD |
1255 | void cds_lfht_lookup(struct cds_lfht *ht, void *key, size_t key_len, |
1256 | struct cds_lfht_iter *iter) | |
2ed95849 | 1257 | { |
bb7b2f26 | 1258 | struct cds_lfht_node *node, *next, *dummy_node; |
14044b37 | 1259 | struct _cds_lfht_node *lookup; |
4105056a | 1260 | unsigned long hash, reverse_hash, index, order, size; |
2ed95849 | 1261 | |
732ad076 | 1262 | hash = ht->hash_fct(key, key_len, ht->hash_seed); |
abc490a1 | 1263 | reverse_hash = bit_reverse_ulong(hash); |
464a1ec9 | 1264 | |
4105056a MD |
1265 | size = rcu_dereference(ht->t.size); |
1266 | index = hash & (size - 1); | |
24365af7 | 1267 | order = get_count_order_ulong(index + 1); |
4105056a | 1268 | lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1))) - 1)]; |
f0c29ed7 | 1269 | dbg_printf("lookup hash %lu index %lu order %lu aridx %lu\n", |
554c284e | 1270 | hash, index, order, index & (!order ? 0 : ((1UL << (order - 1)) - 1))); |
bb7b2f26 MD |
1271 | dummy_node = (struct cds_lfht_node *) lookup; |
1272 | /* We can always skip the dummy node initially */ | |
1273 | node = rcu_dereference(dummy_node->p.next); | |
bb7b2f26 | 1274 | node = clear_flag(node); |
2ed95849 | 1275 | for (;;) { |
bb7b2f26 MD |
1276 | if (unlikely(is_end(node))) { |
1277 | node = NULL; | |
abc490a1 | 1278 | break; |
bb7b2f26 | 1279 | } |
cc4fcb10 | 1280 | if (unlikely(node->p.reverse_hash > reverse_hash)) { |
abc490a1 MD |
1281 | node = NULL; |
1282 | break; | |
2ed95849 | 1283 | } |
1b81fe1a | 1284 | next = rcu_dereference(node->p.next); |
adc0de68 | 1285 | if (likely(!is_removed(next)) |
1b81fe1a | 1286 | && !is_dummy(next) |
49c2e2d6 | 1287 | && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) { |
273399de | 1288 | break; |
2ed95849 | 1289 | } |
1b81fe1a | 1290 | node = clear_flag(next); |
2ed95849 | 1291 | } |
1b81fe1a | 1292 | assert(!node || !is_dummy(rcu_dereference(node->p.next))); |
adc0de68 MD |
1293 | iter->node = node; |
1294 | iter->next = next; | |
abc490a1 | 1295 | } |
e0ba718a | 1296 | |
adc0de68 | 1297 | void cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_iter *iter) |
a481e5ff | 1298 | { |
adc0de68 | 1299 | struct cds_lfht_node *node, *next; |
a481e5ff MD |
1300 | unsigned long reverse_hash; |
1301 | void *key; | |
1302 | size_t key_len; | |
1303 | ||
adc0de68 | 1304 | node = iter->node; |
a481e5ff MD |
1305 | reverse_hash = node->p.reverse_hash; |
1306 | key = node->key; | |
1307 | key_len = node->key_len; | |
adc0de68 | 1308 | next = iter->next; |
a481e5ff MD |
1309 | node = clear_flag(next); |
1310 | ||
1311 | for (;;) { | |
bb7b2f26 MD |
1312 | if (unlikely(is_end(node))) { |
1313 | node = NULL; | |
a481e5ff | 1314 | break; |
bb7b2f26 | 1315 | } |
a481e5ff MD |
1316 | if (unlikely(node->p.reverse_hash > reverse_hash)) { |
1317 | node = NULL; | |
1318 | break; | |
1319 | } | |
1320 | next = rcu_dereference(node->p.next); | |
adc0de68 | 1321 | if (likely(!is_removed(next)) |
a481e5ff MD |
1322 | && !is_dummy(next) |
1323 | && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) { | |
1324 | break; | |
1325 | } | |
1326 | node = clear_flag(next); | |
1327 | } | |
1328 | assert(!node || !is_dummy(rcu_dereference(node->p.next))); | |
adc0de68 MD |
1329 | iter->node = node; |
1330 | iter->next = next; | |
a481e5ff MD |
1331 | } |
1332 | ||
14044b37 | 1333 | void cds_lfht_add(struct cds_lfht *ht, struct cds_lfht_node *node) |
abc490a1 | 1334 | { |
4105056a | 1335 | unsigned long hash, size; |
ab7d5fc6 | 1336 | |
49c2e2d6 | 1337 | hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed); |
cc4fcb10 | 1338 | node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash); |
2ed95849 | 1339 | |
4105056a | 1340 | size = rcu_dereference(ht->t.size); |
48ed1c18 | 1341 | (void) _cds_lfht_add(ht, size, node, ADD_DEFAULT, 0); |
4105056a | 1342 | ht_count_add(ht, size); |
3eca1b8c MD |
1343 | } |
1344 | ||
14044b37 | 1345 | struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, |
48ed1c18 | 1346 | struct cds_lfht_node *node) |
3eca1b8c | 1347 | { |
4105056a | 1348 | unsigned long hash, size; |
df44348d | 1349 | struct cds_lfht_node *ret; |
3eca1b8c | 1350 | |
49c2e2d6 | 1351 | hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed); |
cc4fcb10 | 1352 | node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash); |
3eca1b8c | 1353 | |
4105056a | 1354 | size = rcu_dereference(ht->t.size); |
48ed1c18 | 1355 | ret = _cds_lfht_add(ht, size, node, ADD_UNIQUE, 0); |
17f31d1b | 1356 | if (ret == node) |
4105056a | 1357 | ht_count_add(ht, size); |
df44348d | 1358 | return ret; |
2ed95849 MD |
1359 | } |
1360 | ||
48ed1c18 MD |
1361 | struct cds_lfht_node *cds_lfht_replace(struct cds_lfht *ht, |
1362 | struct cds_lfht_node *node) | |
1363 | { | |
1364 | unsigned long hash, size; | |
1365 | struct cds_lfht_node *ret; | |
1366 | ||
1367 | hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed); | |
1368 | node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash); | |
1369 | ||
1370 | size = rcu_dereference(ht->t.size); | |
1371 | ret = _cds_lfht_add(ht, size, node, ADD_REPLACE, 0); | |
1372 | if (ret == NULL) | |
1373 | ht_count_add(ht, size); | |
1374 | return ret; | |
1375 | } | |
1376 | ||
860d07e8 | 1377 | int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_node *node) |
2ed95849 | 1378 | { |
4105056a | 1379 | unsigned long size; |
df44348d | 1380 | int ret; |
abc490a1 | 1381 | |
4105056a | 1382 | size = rcu_dereference(ht->t.size); |
b198f0fd | 1383 | ret = _cds_lfht_del(ht, size, node, 0); |
df44348d | 1384 | if (!ret) |
860d07e8 | 1385 | ht_count_del(ht, size); |
df44348d | 1386 | return ret; |
2ed95849 | 1387 | } |
ab7d5fc6 | 1388 | |
abc490a1 | 1389 | static |
14044b37 | 1390 | int cds_lfht_delete_dummy(struct cds_lfht *ht) |
674f7a69 | 1391 | { |
14044b37 MD |
1392 | struct cds_lfht_node *node; |
1393 | struct _cds_lfht_node *lookup; | |
4105056a | 1394 | unsigned long order, i, size; |
674f7a69 | 1395 | |
abc490a1 | 1396 | /* Check that the table is empty */ |
4105056a | 1397 | lookup = &ht->t.tbl[0]->nodes[0]; |
14044b37 | 1398 | node = (struct cds_lfht_node *) lookup; |
abc490a1 | 1399 | do { |
1b81fe1a MD |
1400 | node = clear_flag(node)->p.next; |
1401 | if (!is_dummy(node)) | |
abc490a1 | 1402 | return -EPERM; |
273399de | 1403 | assert(!is_removed(node)); |
bb7b2f26 | 1404 | } while (!is_end(node)); |
4105056a MD |
1405 | /* |
1406 | * size accessed without rcu_dereference because hash table is | |
1407 | * being destroyed. | |
1408 | */ | |
1409 | size = ht->t.size; | |
abc490a1 | 1410 | /* Internal sanity check: all nodes left should be dummy */ |
4105056a | 1411 | for (order = 0; order < get_count_order_ulong(size) + 1; order++) { |
24365af7 MD |
1412 | unsigned long len; |
1413 | ||
1414 | len = !order ? 1 : 1UL << (order - 1); | |
1415 | for (i = 0; i < len; i++) { | |
f0c29ed7 | 1416 | dbg_printf("delete order %lu i %lu hash %lu\n", |
24365af7 | 1417 | order, i, |
4105056a MD |
1418 | bit_reverse_ulong(ht->t.tbl[order]->nodes[i].reverse_hash)); |
1419 | assert(is_dummy(ht->t.tbl[order]->nodes[i].next)); | |
24365af7 | 1420 | } |
4105056a | 1421 | poison_free(ht->t.tbl[order]); |
674f7a69 | 1422 | } |
abc490a1 | 1423 | return 0; |
674f7a69 MD |
1424 | } |
1425 | ||
1426 | /* | |
1427 | * Should only be called when no more concurrent readers nor writers can | |
1428 | * possibly access the table. | |
1429 | */ | |
b7d619b0 | 1430 | int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr) |
674f7a69 | 1431 | { |
5e28c532 MD |
1432 | int ret; |
1433 | ||
848d4088 | 1434 | /* Wait for in-flight resize operations to complete */ |
33c7c748 | 1435 | CMM_STORE_SHARED(ht->in_progress_destroy, 1); |
848d4088 MD |
1436 | while (uatomic_read(&ht->in_progress_resize)) |
1437 | poll(NULL, 0, 100); /* wait for 100ms */ | |
14044b37 | 1438 | ret = cds_lfht_delete_dummy(ht); |
abc490a1 MD |
1439 | if (ret) |
1440 | return ret; | |
df44348d | 1441 | free_per_cpu_items_count(ht->percpu_count); |
b7d619b0 MD |
1442 | if (attr) |
1443 | *attr = ht->resize_attr; | |
98808fb1 | 1444 | poison_free(ht); |
5e28c532 | 1445 | return ret; |
674f7a69 MD |
1446 | } |
1447 | ||
14044b37 | 1448 | void cds_lfht_count_nodes(struct cds_lfht *ht, |
973e5e1b | 1449 | unsigned long *approx_before, |
273399de | 1450 | unsigned long *count, |
973e5e1b MD |
1451 | unsigned long *removed, |
1452 | unsigned long *approx_after) | |
273399de | 1453 | { |
14044b37 MD |
1454 | struct cds_lfht_node *node, *next; |
1455 | struct _cds_lfht_node *lookup; | |
24365af7 | 1456 | unsigned long nr_dummy = 0; |
273399de | 1457 | |
7ed7682f | 1458 | *approx_before = 0; |
973e5e1b MD |
1459 | if (nr_cpus_mask >= 0) { |
1460 | int i; | |
1461 | ||
1462 | for (i = 0; i < nr_cpus_mask + 1; i++) { | |
1463 | *approx_before += uatomic_read(&ht->percpu_count[i].add); | |
1464 | *approx_before -= uatomic_read(&ht->percpu_count[i].del); | |
1465 | } | |
1466 | } | |
1467 | ||
273399de MD |
1468 | *count = 0; |
1469 | *removed = 0; | |
1470 | ||
24365af7 | 1471 | /* Count non-dummy nodes in the table */ |
4105056a | 1472 | lookup = &ht->t.tbl[0]->nodes[0]; |
14044b37 | 1473 | node = (struct cds_lfht_node *) lookup; |
273399de | 1474 | do { |
cc4fcb10 | 1475 | next = rcu_dereference(node->p.next); |
b198f0fd | 1476 | if (is_removed(next)) { |
973e5e1b MD |
1477 | if (!is_dummy(next)) |
1478 | (*removed)++; | |
1479 | else | |
1480 | (nr_dummy)++; | |
1b81fe1a | 1481 | } else if (!is_dummy(next)) |
273399de | 1482 | (*count)++; |
24365af7 MD |
1483 | else |
1484 | (nr_dummy)++; | |
273399de | 1485 | node = clear_flag(next); |
bb7b2f26 | 1486 | } while (!is_end(node)); |
f0c29ed7 | 1487 | dbg_printf("number of dummy nodes: %lu\n", nr_dummy); |
7ed7682f | 1488 | *approx_after = 0; |
973e5e1b MD |
1489 | if (nr_cpus_mask >= 0) { |
1490 | int i; | |
1491 | ||
1492 | for (i = 0; i < nr_cpus_mask + 1; i++) { | |
1493 | *approx_after += uatomic_read(&ht->percpu_count[i].add); | |
1494 | *approx_after -= uatomic_read(&ht->percpu_count[i].del); | |
1495 | } | |
1496 | } | |
273399de MD |
1497 | } |
1498 | ||
1475579c | 1499 | /* called with resize mutex held */ |
abc490a1 | 1500 | static |
4105056a | 1501 | void _do_cds_lfht_grow(struct cds_lfht *ht, |
1475579c | 1502 | unsigned long old_size, unsigned long new_size) |
abc490a1 | 1503 | { |
1475579c | 1504 | unsigned long old_order, new_order; |
1475579c MD |
1505 | |
1506 | old_order = get_count_order_ulong(old_size) + 1; | |
1507 | new_order = get_count_order_ulong(new_size) + 1; | |
1508 | printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", | |
1509 | old_size, old_order, new_size, new_order); | |
1475579c | 1510 | assert(new_size > old_size); |
4105056a | 1511 | init_table(ht, old_order, new_order - old_order); |
abc490a1 MD |
1512 | } |
1513 | ||
1514 | /* called with resize mutex held */ | |
1515 | static | |
4105056a | 1516 | void _do_cds_lfht_shrink(struct cds_lfht *ht, |
1475579c | 1517 | unsigned long old_size, unsigned long new_size) |
464a1ec9 | 1518 | { |
1475579c | 1519 | unsigned long old_order, new_order; |
464a1ec9 | 1520 | |
cd95516d | 1521 | new_size = max(new_size, MIN_TABLE_SIZE); |
24365af7 | 1522 | old_order = get_count_order_ulong(old_size) + 1; |
24365af7 | 1523 | new_order = get_count_order_ulong(new_size) + 1; |
df44348d | 1524 | printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", |
df03fab8 | 1525 | old_size, old_order, new_size, new_order); |
1475579c | 1526 | assert(new_size < old_size); |
1475579c | 1527 | |
4105056a MD |
1528 | /* Remove and unlink all dummy nodes to remove. */ |
1529 | fini_table(ht, new_order, old_order - new_order); | |
464a1ec9 MD |
1530 | } |
1531 | ||
1475579c MD |
1532 | |
1533 | /* called with resize mutex held */ | |
1534 | static | |
1535 | void _do_cds_lfht_resize(struct cds_lfht *ht) | |
1536 | { | |
1537 | unsigned long new_size, old_size; | |
4105056a MD |
1538 | |
1539 | /* | |
1540 | * Resize table, re-do if the target size has changed under us. | |
1541 | */ | |
1542 | do { | |
1543 | ht->t.resize_initiated = 1; | |
1544 | old_size = ht->t.size; | |
1545 | new_size = CMM_LOAD_SHARED(ht->t.resize_target); | |
1546 | if (old_size < new_size) | |
1547 | _do_cds_lfht_grow(ht, old_size, new_size); | |
1548 | else if (old_size > new_size) | |
1549 | _do_cds_lfht_shrink(ht, old_size, new_size); | |
1550 | ht->t.resize_initiated = 0; | |
1551 | /* write resize_initiated before read resize_target */ | |
1552 | cmm_smp_mb(); | |
4d676753 | 1553 | } while (ht->t.size != CMM_LOAD_SHARED(ht->t.resize_target)); |
1475579c MD |
1554 | } |
1555 | ||
abc490a1 | 1556 | static |
4105056a | 1557 | unsigned long resize_target_update(struct cds_lfht *ht, unsigned long size, |
f9830efd | 1558 | int growth_order) |
464a1ec9 | 1559 | { |
4105056a MD |
1560 | return _uatomic_max(&ht->t.resize_target, |
1561 | size << growth_order); | |
464a1ec9 MD |
1562 | } |
1563 | ||
1475579c | 1564 | static |
4105056a | 1565 | void resize_target_update_count(struct cds_lfht *ht, |
b8af5011 | 1566 | unsigned long count) |
1475579c | 1567 | { |
cd95516d | 1568 | count = max(count, MIN_TABLE_SIZE); |
4105056a | 1569 | uatomic_set(&ht->t.resize_target, count); |
1475579c MD |
1570 | } |
1571 | ||
1572 | void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size) | |
464a1ec9 | 1573 | { |
4105056a MD |
1574 | resize_target_update_count(ht, new_size); |
1575 | CMM_STORE_SHARED(ht->t.resize_initiated, 1); | |
5f511391 | 1576 | ht->cds_lfht_rcu_thread_offline(); |
1475579c MD |
1577 | pthread_mutex_lock(&ht->resize_mutex); |
1578 | _do_cds_lfht_resize(ht); | |
1579 | pthread_mutex_unlock(&ht->resize_mutex); | |
5f511391 | 1580 | ht->cds_lfht_rcu_thread_online(); |
abc490a1 | 1581 | } |
464a1ec9 | 1582 | |
abc490a1 MD |
1583 | static |
1584 | void do_resize_cb(struct rcu_head *head) | |
1585 | { | |
1586 | struct rcu_resize_work *work = | |
1587 | caa_container_of(head, struct rcu_resize_work, head); | |
14044b37 | 1588 | struct cds_lfht *ht = work->ht; |
abc490a1 | 1589 | |
5f511391 | 1590 | ht->cds_lfht_rcu_thread_offline(); |
abc490a1 | 1591 | pthread_mutex_lock(&ht->resize_mutex); |
14044b37 | 1592 | _do_cds_lfht_resize(ht); |
abc490a1 | 1593 | pthread_mutex_unlock(&ht->resize_mutex); |
5f511391 | 1594 | ht->cds_lfht_rcu_thread_online(); |
98808fb1 | 1595 | poison_free(work); |
848d4088 MD |
1596 | cmm_smp_mb(); /* finish resize before decrement */ |
1597 | uatomic_dec(&ht->in_progress_resize); | |
464a1ec9 MD |
1598 | } |
1599 | ||
abc490a1 | 1600 | static |
4105056a | 1601 | void cds_lfht_resize_lazy(struct cds_lfht *ht, unsigned long size, int growth) |
ab7d5fc6 | 1602 | { |
abc490a1 | 1603 | struct rcu_resize_work *work; |
f9830efd | 1604 | unsigned long target_size; |
abc490a1 | 1605 | |
4105056a MD |
1606 | target_size = resize_target_update(ht, size, growth); |
1607 | /* Store resize_target before read resize_initiated */ | |
1608 | cmm_smp_mb(); | |
1609 | if (!CMM_LOAD_SHARED(ht->t.resize_initiated) && size < target_size) { | |
848d4088 MD |
1610 | uatomic_inc(&ht->in_progress_resize); |
1611 | cmm_smp_mb(); /* increment resize count before calling it */ | |
f9830efd MD |
1612 | work = malloc(sizeof(*work)); |
1613 | work->ht = ht; | |
14044b37 | 1614 | ht->cds_lfht_call_rcu(&work->head, do_resize_cb); |
4105056a | 1615 | CMM_STORE_SHARED(ht->t.resize_initiated, 1); |
f9830efd | 1616 | } |
ab7d5fc6 | 1617 | } |
3171717f | 1618 | |
f8994aee MD |
1619 | #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) |
1620 | ||
3171717f | 1621 | static |
4105056a | 1622 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, |
3171717f MD |
1623 | unsigned long count) |
1624 | { | |
1625 | struct rcu_resize_work *work; | |
3171717f | 1626 | |
b8af5011 MD |
1627 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) |
1628 | return; | |
4105056a MD |
1629 | resize_target_update_count(ht, count); |
1630 | /* Store resize_target before read resize_initiated */ | |
1631 | cmm_smp_mb(); | |
1632 | if (!CMM_LOAD_SHARED(ht->t.resize_initiated)) { | |
3171717f MD |
1633 | uatomic_inc(&ht->in_progress_resize); |
1634 | cmm_smp_mb(); /* increment resize count before calling it */ | |
1635 | work = malloc(sizeof(*work)); | |
1636 | work->ht = ht; | |
1637 | ht->cds_lfht_call_rcu(&work->head, do_resize_cb); | |
4105056a | 1638 | CMM_STORE_SHARED(ht->t.resize_initiated, 1); |
3171717f MD |
1639 | } |
1640 | } | |
f8994aee MD |
1641 | |
1642 | #endif |