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fa68aa62 MD |
1 | /* |
2 | * rculfhash.c | |
3 | * | |
4 | * Userspace RCU library - Lock-Free Resizable RCU Hash Table | |
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 | |
21 | */ | |
22 | ||
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 | * | |
32 | * Some specificities of this Lock-Free Resizable RCU Hash Table | |
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. | |
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. | |
d6b18934 | 56 | * - Split-counters are used to keep track of the number of |
fa68aa62 MD |
57 | * nodes within the hash table for automatic resize triggering. |
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. | |
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. | |
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 | |
d6b18934 DG |
94 | * this order (except for order 0). |
95 | * - synchronzie_rcu is used to garbage-collect the old dummy node table. | |
fa68aa62 MD |
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. | |
d6b18934 DG |
99 | * |
100 | * Dummy node tables: | |
101 | * | |
102 | * hash table hash table the last all dummy node tables | |
103 | * order size dummy node 0 1 2 3 4 5 6(index) | |
104 | * table size | |
105 | * 0 1 1 1 | |
106 | * 1 2 1 1 1 | |
107 | * 2 4 2 1 1 2 | |
108 | * 3 8 4 1 1 2 4 | |
109 | * 4 16 8 1 1 2 4 8 | |
110 | * 5 32 16 1 1 2 4 8 16 | |
111 | * 6 64 32 1 1 2 4 8 16 32 | |
112 | * | |
113 | * When growing/shrinking, we only focus on the last dummy node table | |
114 | * which size is (!order ? 1 : (1 << (order -1))). | |
115 | * | |
116 | * Example for growing/shrinking: | |
117 | * grow hash table from order 5 to 6: init the index=6 dummy node table | |
118 | * shrink hash table from order 6 to 5: fini the index=6 dummy node table | |
119 | * | |
fa68aa62 MD |
120 | * A bit of ascii art explanation: |
121 | * | |
122 | * Order index is the off-by-one compare to the actual power of 2 because | |
123 | * we use index 0 to deal with the 0 special-case. | |
124 | * | |
125 | * This shows the nodes for a small table ordered by reversed bits: | |
126 | * | |
127 | * bits reverse | |
128 | * 0 000 000 | |
129 | * 4 100 001 | |
130 | * 2 010 010 | |
131 | * 6 110 011 | |
132 | * 1 001 100 | |
133 | * 5 101 101 | |
134 | * 3 011 110 | |
135 | * 7 111 111 | |
136 | * | |
137 | * This shows the nodes in order of non-reversed bits, linked by | |
138 | * reversed-bit order. | |
139 | * | |
140 | * order bits reverse | |
141 | * 0 0 000 000 | |
d6b18934 DG |
142 | * 1 | 1 001 100 <- |
143 | * 2 | | 2 010 010 <- | | |
fa68aa62 | 144 | * | | | 3 011 110 | <- | |
fa68aa62 MD |
145 | * 3 -> | | | 4 100 001 | | |
146 | * -> | | 5 101 101 | | |
147 | * -> | 6 110 011 | |
148 | * -> 7 111 111 | |
149 | */ | |
150 | ||
151 | #define _LGPL_SOURCE | |
152 | #include <stdlib.h> | |
153 | #include <errno.h> | |
154 | #include <assert.h> | |
155 | #include <stdio.h> | |
156 | #include <stdint.h> | |
157 | #include <string.h> | |
158 | ||
d6b18934 | 159 | #include "config.h" |
fa68aa62 MD |
160 | #include <urcu.h> |
161 | #include <urcu-call-rcu.h> | |
162 | #include <urcu/arch.h> | |
163 | #include <urcu/uatomic.h> | |
164 | #include <urcu/compiler.h> | |
fa68aa62 MD |
165 | #include <stdio.h> |
166 | #include <pthread.h> | |
167 | ||
f6a9efaa DG |
168 | #include "rculfhash.h" |
169 | ||
fa68aa62 MD |
170 | #ifdef DEBUG |
171 | #define dbg_printf(fmt, args...) printf("[debug rculfhash] " fmt, ## args) | |
172 | #else | |
173 | #define dbg_printf(fmt, args...) | |
174 | #endif | |
175 | ||
176 | /* | |
d6b18934 | 177 | * Split-counters lazily update the global counter each 1024 |
fa68aa62 MD |
178 | * addition/removal. It automatically keeps track of resize required. |
179 | * We use the bucket length as indicator for need to expand for small | |
180 | * tables and machines lacking per-cpu data suppport. | |
181 | */ | |
182 | #define COUNT_COMMIT_ORDER 10 | |
d6b18934 | 183 | #define DEFAULT_SPLIT_COUNT_MASK 0xFUL |
fa68aa62 MD |
184 | #define CHAIN_LEN_TARGET 1 |
185 | #define CHAIN_LEN_RESIZE_THRESHOLD 3 | |
186 | ||
187 | /* | |
188 | * Define the minimum table size. | |
189 | */ | |
190 | #define MIN_TABLE_SIZE 1 | |
191 | ||
192 | #if (CAA_BITS_PER_LONG == 32) | |
193 | #define MAX_TABLE_ORDER 32 | |
194 | #else | |
195 | #define MAX_TABLE_ORDER 64 | |
196 | #endif | |
197 | ||
198 | /* | |
199 | * Minimum number of dummy nodes to touch per thread to parallelize grow/shrink. | |
200 | */ | |
201 | #define MIN_PARTITION_PER_THREAD_ORDER 12 | |
202 | #define MIN_PARTITION_PER_THREAD (1UL << MIN_PARTITION_PER_THREAD_ORDER) | |
203 | ||
204 | #ifndef min | |
205 | #define min(a, b) ((a) < (b) ? (a) : (b)) | |
206 | #endif | |
207 | ||
208 | #ifndef max | |
209 | #define max(a, b) ((a) > (b) ? (a) : (b)) | |
210 | #endif | |
211 | ||
212 | /* | |
213 | * The removed flag needs to be updated atomically with the pointer. | |
214 | * It indicates that no node must attach to the node scheduled for | |
215 | * removal, and that node garbage collection must be performed. | |
216 | * The dummy flag does not require to be updated atomically with the | |
217 | * pointer, but it is added as a pointer low bit flag to save space. | |
218 | */ | |
219 | #define REMOVED_FLAG (1UL << 0) | |
220 | #define DUMMY_FLAG (1UL << 1) | |
221 | #define FLAGS_MASK ((1UL << 2) - 1) | |
222 | ||
223 | /* Value of the end pointer. Should not interact with flags. */ | |
224 | #define END_VALUE NULL | |
225 | ||
d6b18934 DG |
226 | /* |
227 | * ht_items_count: Split-counters counting the number of node addition | |
228 | * and removal in the table. Only used if the CDS_LFHT_ACCOUNTING flag | |
229 | * is set at hash table creation. | |
230 | * | |
231 | * These are free-running counters, never reset to zero. They count the | |
232 | * number of add/remove, and trigger every (1 << COUNT_COMMIT_ORDER) | |
233 | * operations to update the global counter. We choose a power-of-2 value | |
234 | * for the trigger to deal with 32 or 64-bit overflow of the counter. | |
235 | */ | |
fa68aa62 MD |
236 | struct ht_items_count { |
237 | unsigned long add, del; | |
238 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); | |
239 | ||
d6b18934 DG |
240 | /* |
241 | * rcu_level: Contains the per order-index-level dummy node table. The | |
242 | * size of each dummy node table is half the number of hashes contained | |
243 | * in this order (except for order 0). The minimum allocation size | |
244 | * parameter allows combining the dummy node arrays of the lowermost | |
245 | * levels to improve cache locality for small index orders. | |
246 | */ | |
fa68aa62 | 247 | struct rcu_level { |
d6b18934 | 248 | /* Note: manually update allocation length when adding a field */ |
fa68aa62 MD |
249 | struct _cds_lfht_node nodes[0]; |
250 | }; | |
251 | ||
d6b18934 DG |
252 | /* |
253 | * rcu_table: Contains the size and desired new size if a resize | |
254 | * operation is in progress, as well as the statically-sized array of | |
255 | * rcu_level pointers. | |
256 | */ | |
fa68aa62 MD |
257 | struct rcu_table { |
258 | unsigned long size; /* always a power of 2, shared (RCU) */ | |
259 | unsigned long resize_target; | |
260 | int resize_initiated; | |
261 | struct rcu_level *tbl[MAX_TABLE_ORDER]; | |
262 | }; | |
263 | ||
d6b18934 DG |
264 | /* |
265 | * cds_lfht: Top-level data structure representing a lock-free hash | |
266 | * table. Defined in the implementation file to make it be an opaque | |
267 | * cookie to users. | |
268 | */ | |
fa68aa62 MD |
269 | struct cds_lfht { |
270 | struct rcu_table t; | |
271 | cds_lfht_hash_fct hash_fct; | |
272 | cds_lfht_compare_fct compare_fct; | |
d6b18934 DG |
273 | unsigned long min_alloc_order; |
274 | unsigned long min_alloc_size; | |
fa68aa62 MD |
275 | unsigned long hash_seed; |
276 | int flags; | |
277 | /* | |
278 | * We need to put the work threads offline (QSBR) when taking this | |
279 | * mutex, because we use synchronize_rcu within this mutex critical | |
280 | * section, which waits on read-side critical sections, and could | |
281 | * therefore cause grace-period deadlock if we hold off RCU G.P. | |
282 | * completion. | |
283 | */ | |
284 | pthread_mutex_t resize_mutex; /* resize mutex: add/del mutex */ | |
285 | unsigned int in_progress_resize, in_progress_destroy; | |
286 | void (*cds_lfht_call_rcu)(struct rcu_head *head, | |
287 | void (*func)(struct rcu_head *head)); | |
288 | void (*cds_lfht_synchronize_rcu)(void); | |
289 | void (*cds_lfht_rcu_read_lock)(void); | |
290 | void (*cds_lfht_rcu_read_unlock)(void); | |
291 | void (*cds_lfht_rcu_thread_offline)(void); | |
292 | void (*cds_lfht_rcu_thread_online)(void); | |
293 | void (*cds_lfht_rcu_register_thread)(void); | |
294 | void (*cds_lfht_rcu_unregister_thread)(void); | |
295 | pthread_attr_t *resize_attr; /* Resize threads attributes */ | |
296 | long count; /* global approximate item count */ | |
d6b18934 | 297 | struct ht_items_count *split_count; /* split item count */ |
fa68aa62 MD |
298 | }; |
299 | ||
d6b18934 DG |
300 | /* |
301 | * rcu_resize_work: Contains arguments passed to RCU worker thread | |
302 | * responsible for performing lazy resize. | |
303 | */ | |
fa68aa62 MD |
304 | struct rcu_resize_work { |
305 | struct rcu_head head; | |
306 | struct cds_lfht *ht; | |
307 | }; | |
308 | ||
d6b18934 DG |
309 | /* |
310 | * partition_resize_work: Contains arguments passed to worker threads | |
311 | * executing the hash table resize on partitions of the hash table | |
312 | * assigned to each processor's worker thread. | |
313 | */ | |
fa68aa62 | 314 | struct partition_resize_work { |
d6b18934 | 315 | pthread_t thread_id; |
fa68aa62 MD |
316 | struct cds_lfht *ht; |
317 | unsigned long i, start, len; | |
318 | void (*fct)(struct cds_lfht *ht, unsigned long i, | |
319 | unsigned long start, unsigned long len); | |
320 | }; | |
321 | ||
fa68aa62 | 322 | static |
d6b18934 DG |
323 | void _cds_lfht_add(struct cds_lfht *ht, |
324 | unsigned long size, | |
325 | struct cds_lfht_node *node, | |
326 | struct cds_lfht_iter *unique_ret, | |
327 | int dummy); | |
fa68aa62 MD |
328 | |
329 | /* | |
330 | * Algorithm to reverse bits in a word by lookup table, extended to | |
331 | * 64-bit words. | |
332 | * Source: | |
333 | * http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable | |
334 | * Originally from Public Domain. | |
335 | */ | |
336 | ||
337 | static const uint8_t BitReverseTable256[256] = | |
338 | { | |
339 | #define R2(n) (n), (n) + 2*64, (n) + 1*64, (n) + 3*64 | |
340 | #define R4(n) R2(n), R2((n) + 2*16), R2((n) + 1*16), R2((n) + 3*16) | |
341 | #define R6(n) R4(n), R4((n) + 2*4 ), R4((n) + 1*4 ), R4((n) + 3*4 ) | |
342 | R6(0), R6(2), R6(1), R6(3) | |
343 | }; | |
344 | #undef R2 | |
345 | #undef R4 | |
346 | #undef R6 | |
347 | ||
348 | static | |
349 | uint8_t bit_reverse_u8(uint8_t v) | |
350 | { | |
351 | return BitReverseTable256[v]; | |
352 | } | |
353 | ||
354 | static __attribute__((unused)) | |
355 | uint32_t bit_reverse_u32(uint32_t v) | |
356 | { | |
357 | return ((uint32_t) bit_reverse_u8(v) << 24) | | |
358 | ((uint32_t) bit_reverse_u8(v >> 8) << 16) | | |
359 | ((uint32_t) bit_reverse_u8(v >> 16) << 8) | | |
360 | ((uint32_t) bit_reverse_u8(v >> 24)); | |
361 | } | |
362 | ||
363 | static __attribute__((unused)) | |
364 | uint64_t bit_reverse_u64(uint64_t v) | |
365 | { | |
366 | return ((uint64_t) bit_reverse_u8(v) << 56) | | |
367 | ((uint64_t) bit_reverse_u8(v >> 8) << 48) | | |
368 | ((uint64_t) bit_reverse_u8(v >> 16) << 40) | | |
369 | ((uint64_t) bit_reverse_u8(v >> 24) << 32) | | |
370 | ((uint64_t) bit_reverse_u8(v >> 32) << 24) | | |
371 | ((uint64_t) bit_reverse_u8(v >> 40) << 16) | | |
372 | ((uint64_t) bit_reverse_u8(v >> 48) << 8) | | |
373 | ((uint64_t) bit_reverse_u8(v >> 56)); | |
374 | } | |
375 | ||
376 | static | |
377 | unsigned long bit_reverse_ulong(unsigned long v) | |
378 | { | |
379 | #if (CAA_BITS_PER_LONG == 32) | |
380 | return bit_reverse_u32(v); | |
381 | #else | |
382 | return bit_reverse_u64(v); | |
383 | #endif | |
384 | } | |
385 | ||
386 | /* | |
387 | * fls: returns the position of the most significant bit. | |
388 | * Returns 0 if no bit is set, else returns the position of the most | |
389 | * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit). | |
390 | */ | |
391 | #if defined(__i386) || defined(__x86_64) | |
392 | static inline | |
393 | unsigned int fls_u32(uint32_t x) | |
394 | { | |
395 | int r; | |
396 | ||
397 | asm("bsrl %1,%0\n\t" | |
398 | "jnz 1f\n\t" | |
399 | "movl $-1,%0\n\t" | |
400 | "1:\n\t" | |
401 | : "=r" (r) : "rm" (x)); | |
402 | return r + 1; | |
403 | } | |
404 | #define HAS_FLS_U32 | |
405 | #endif | |
406 | ||
407 | #if defined(__x86_64) | |
408 | static inline | |
409 | unsigned int fls_u64(uint64_t x) | |
410 | { | |
411 | long r; | |
412 | ||
413 | asm("bsrq %1,%0\n\t" | |
414 | "jnz 1f\n\t" | |
415 | "movq $-1,%0\n\t" | |
416 | "1:\n\t" | |
417 | : "=r" (r) : "rm" (x)); | |
418 | return r + 1; | |
419 | } | |
420 | #define HAS_FLS_U64 | |
421 | #endif | |
422 | ||
423 | #ifndef HAS_FLS_U64 | |
424 | static __attribute__((unused)) | |
425 | unsigned int fls_u64(uint64_t x) | |
426 | { | |
427 | unsigned int r = 64; | |
428 | ||
429 | if (!x) | |
430 | return 0; | |
431 | ||
432 | if (!(x & 0xFFFFFFFF00000000ULL)) { | |
433 | x <<= 32; | |
434 | r -= 32; | |
435 | } | |
436 | if (!(x & 0xFFFF000000000000ULL)) { | |
437 | x <<= 16; | |
438 | r -= 16; | |
439 | } | |
440 | if (!(x & 0xFF00000000000000ULL)) { | |
441 | x <<= 8; | |
442 | r -= 8; | |
443 | } | |
444 | if (!(x & 0xF000000000000000ULL)) { | |
445 | x <<= 4; | |
446 | r -= 4; | |
447 | } | |
448 | if (!(x & 0xC000000000000000ULL)) { | |
449 | x <<= 2; | |
450 | r -= 2; | |
451 | } | |
452 | if (!(x & 0x8000000000000000ULL)) { | |
453 | x <<= 1; | |
454 | r -= 1; | |
455 | } | |
456 | return r; | |
457 | } | |
458 | #endif | |
459 | ||
460 | #ifndef HAS_FLS_U32 | |
461 | static __attribute__((unused)) | |
462 | unsigned int fls_u32(uint32_t x) | |
463 | { | |
464 | unsigned int r = 32; | |
465 | ||
466 | if (!x) | |
467 | return 0; | |
468 | if (!(x & 0xFFFF0000U)) { | |
469 | x <<= 16; | |
470 | r -= 16; | |
471 | } | |
472 | if (!(x & 0xFF000000U)) { | |
473 | x <<= 8; | |
474 | r -= 8; | |
475 | } | |
476 | if (!(x & 0xF0000000U)) { | |
477 | x <<= 4; | |
478 | r -= 4; | |
479 | } | |
480 | if (!(x & 0xC0000000U)) { | |
481 | x <<= 2; | |
482 | r -= 2; | |
483 | } | |
484 | if (!(x & 0x80000000U)) { | |
485 | x <<= 1; | |
486 | r -= 1; | |
487 | } | |
488 | return r; | |
489 | } | |
490 | #endif | |
491 | ||
492 | unsigned int fls_ulong(unsigned long x) | |
493 | { | |
d6b18934 | 494 | #if (CAA_BITS_PER_LONG == 32) |
fa68aa62 MD |
495 | return fls_u32(x); |
496 | #else | |
497 | return fls_u64(x); | |
498 | #endif | |
499 | } | |
500 | ||
d6b18934 DG |
501 | /* |
502 | * Return the minimum order for which x <= (1UL << order). | |
503 | * Return -1 if x is 0. | |
504 | */ | |
fa68aa62 MD |
505 | int get_count_order_u32(uint32_t x) |
506 | { | |
d6b18934 DG |
507 | if (!x) |
508 | return -1; | |
fa68aa62 | 509 | |
d6b18934 | 510 | return fls_u32(x - 1); |
fa68aa62 MD |
511 | } |
512 | ||
d6b18934 DG |
513 | /* |
514 | * Return the minimum order for which x <= (1UL << order). | |
515 | * Return -1 if x is 0. | |
516 | */ | |
fa68aa62 MD |
517 | int get_count_order_ulong(unsigned long x) |
518 | { | |
d6b18934 DG |
519 | if (!x) |
520 | return -1; | |
fa68aa62 | 521 | |
d6b18934 | 522 | return fls_ulong(x - 1); |
fa68aa62 MD |
523 | } |
524 | ||
525 | #ifdef POISON_FREE | |
d6b18934 DG |
526 | #define poison_free(ptr) \ |
527 | do { \ | |
528 | if (ptr) { \ | |
529 | memset(ptr, 0x42, sizeof(*(ptr))); \ | |
530 | free(ptr); \ | |
531 | } \ | |
fa68aa62 MD |
532 | } while (0) |
533 | #else | |
534 | #define poison_free(ptr) free(ptr) | |
535 | #endif | |
536 | ||
537 | static | |
538 | void cds_lfht_resize_lazy(struct cds_lfht *ht, unsigned long size, int growth); | |
539 | ||
fa68aa62 MD |
540 | static |
541 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, | |
542 | unsigned long count); | |
543 | ||
544 | static long nr_cpus_mask = -1; | |
d6b18934 DG |
545 | static long split_count_mask = -1; |
546 | ||
547 | #if defined(HAVE_SYSCONF) | |
548 | static void ht_init_nr_cpus_mask(void) | |
549 | { | |
550 | long maxcpus; | |
551 | ||
552 | maxcpus = sysconf(_SC_NPROCESSORS_CONF); | |
553 | if (maxcpus <= 0) { | |
554 | nr_cpus_mask = -2; | |
555 | return; | |
556 | } | |
557 | /* | |
558 | * round up number of CPUs to next power of two, so we | |
559 | * can use & for modulo. | |
560 | */ | |
561 | maxcpus = 1UL << get_count_order_ulong(maxcpus); | |
562 | nr_cpus_mask = maxcpus - 1; | |
563 | } | |
564 | #else /* #if defined(HAVE_SYSCONF) */ | |
565 | static void ht_init_nr_cpus_mask(void) | |
566 | { | |
567 | nr_cpus_mask = -2; | |
568 | } | |
569 | #endif /* #else #if defined(HAVE_SYSCONF) */ | |
fa68aa62 MD |
570 | |
571 | static | |
d6b18934 | 572 | void alloc_split_items_count(struct cds_lfht *ht) |
fa68aa62 MD |
573 | { |
574 | struct ht_items_count *count; | |
575 | ||
d6b18934 DG |
576 | if (nr_cpus_mask == -1) { |
577 | ht_init_nr_cpus_mask(); | |
578 | if (nr_cpus_mask < 0) | |
579 | split_count_mask = DEFAULT_SPLIT_COUNT_MASK; | |
580 | else | |
581 | split_count_mask = nr_cpus_mask; | |
fa68aa62 | 582 | } |
d6b18934 DG |
583 | |
584 | assert(split_count_mask >= 0); | |
585 | ||
586 | if (ht->flags & CDS_LFHT_ACCOUNTING) { | |
587 | ht->split_count = calloc(split_count_mask + 1, sizeof(*count)); | |
588 | assert(ht->split_count); | |
589 | } else { | |
590 | ht->split_count = NULL; | |
fa68aa62 MD |
591 | } |
592 | } | |
593 | ||
594 | static | |
d6b18934 | 595 | void free_split_items_count(struct cds_lfht *ht) |
fa68aa62 | 596 | { |
d6b18934 | 597 | poison_free(ht->split_count); |
fa68aa62 MD |
598 | } |
599 | ||
d6b18934 | 600 | #if defined(HAVE_SCHED_GETCPU) |
fa68aa62 | 601 | static |
d6b18934 | 602 | int ht_get_split_count_index(unsigned long hash) |
fa68aa62 MD |
603 | { |
604 | int cpu; | |
605 | ||
d6b18934 | 606 | assert(split_count_mask >= 0); |
fa68aa62 | 607 | cpu = sched_getcpu(); |
6e59ae26 | 608 | if (caa_unlikely(cpu < 0)) |
d6b18934 | 609 | return hash & split_count_mask; |
fa68aa62 | 610 | else |
d6b18934 | 611 | return cpu & split_count_mask; |
fa68aa62 | 612 | } |
d6b18934 DG |
613 | #else /* #if defined(HAVE_SCHED_GETCPU) */ |
614 | static | |
615 | int ht_get_split_count_index(unsigned long hash) | |
616 | { | |
617 | return hash & split_count_mask; | |
618 | } | |
619 | #endif /* #else #if defined(HAVE_SCHED_GETCPU) */ | |
fa68aa62 MD |
620 | |
621 | static | |
d6b18934 | 622 | void ht_count_add(struct cds_lfht *ht, unsigned long size, unsigned long hash) |
fa68aa62 | 623 | { |
d6b18934 DG |
624 | unsigned long split_count; |
625 | int index; | |
fa68aa62 | 626 | |
6e59ae26 | 627 | if (caa_unlikely(!ht->split_count)) |
fa68aa62 | 628 | return; |
d6b18934 DG |
629 | index = ht_get_split_count_index(hash); |
630 | split_count = uatomic_add_return(&ht->split_count[index].add, 1); | |
6e59ae26 | 631 | if (caa_unlikely(!(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) { |
fa68aa62 MD |
632 | long count; |
633 | ||
d6b18934 | 634 | dbg_printf("add split count %lu\n", split_count); |
fa68aa62 MD |
635 | count = uatomic_add_return(&ht->count, |
636 | 1UL << COUNT_COMMIT_ORDER); | |
637 | /* If power of 2 */ | |
638 | if (!(count & (count - 1))) { | |
639 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) < size) | |
640 | return; | |
641 | dbg_printf("add set global %ld\n", count); | |
642 | cds_lfht_resize_lazy_count(ht, size, | |
643 | count >> (CHAIN_LEN_TARGET - 1)); | |
644 | } | |
645 | } | |
646 | } | |
647 | ||
648 | static | |
d6b18934 | 649 | void ht_count_del(struct cds_lfht *ht, unsigned long size, unsigned long hash) |
fa68aa62 | 650 | { |
d6b18934 DG |
651 | unsigned long split_count; |
652 | int index; | |
fa68aa62 | 653 | |
6e59ae26 | 654 | if (caa_unlikely(!ht->split_count)) |
fa68aa62 | 655 | return; |
d6b18934 DG |
656 | index = ht_get_split_count_index(hash); |
657 | split_count = uatomic_add_return(&ht->split_count[index].del, 1); | |
6e59ae26 | 658 | if (caa_unlikely(!(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) { |
fa68aa62 MD |
659 | long count; |
660 | ||
d6b18934 | 661 | dbg_printf("del split count %lu\n", split_count); |
fa68aa62 MD |
662 | count = uatomic_add_return(&ht->count, |
663 | -(1UL << COUNT_COMMIT_ORDER)); | |
664 | /* If power of 2 */ | |
665 | if (!(count & (count - 1))) { | |
666 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) >= size) | |
667 | return; | |
668 | dbg_printf("del set global %ld\n", count); | |
669 | /* | |
670 | * Don't shrink table if the number of nodes is below a | |
671 | * certain threshold. | |
672 | */ | |
d6b18934 | 673 | if (count < (1UL << COUNT_COMMIT_ORDER) * (split_count_mask + 1)) |
fa68aa62 MD |
674 | return; |
675 | cds_lfht_resize_lazy_count(ht, size, | |
676 | count >> (CHAIN_LEN_TARGET - 1)); | |
677 | } | |
678 | } | |
679 | } | |
680 | ||
fa68aa62 MD |
681 | static |
682 | void check_resize(struct cds_lfht *ht, unsigned long size, uint32_t chain_len) | |
683 | { | |
684 | unsigned long count; | |
685 | ||
686 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) | |
687 | return; | |
688 | count = uatomic_read(&ht->count); | |
689 | /* | |
690 | * Use bucket-local length for small table expand and for | |
691 | * environments lacking per-cpu data support. | |
692 | */ | |
693 | if (count >= (1UL << COUNT_COMMIT_ORDER)) | |
694 | return; | |
695 | if (chain_len > 100) | |
696 | dbg_printf("WARNING: large chain length: %u.\n", | |
697 | chain_len); | |
698 | if (chain_len >= CHAIN_LEN_RESIZE_THRESHOLD) | |
699 | cds_lfht_resize_lazy(ht, size, | |
700 | get_count_order_u32(chain_len - (CHAIN_LEN_TARGET - 1))); | |
701 | } | |
702 | ||
703 | static | |
704 | struct cds_lfht_node *clear_flag(struct cds_lfht_node *node) | |
705 | { | |
706 | return (struct cds_lfht_node *) (((unsigned long) node) & ~FLAGS_MASK); | |
707 | } | |
708 | ||
709 | static | |
710 | int is_removed(struct cds_lfht_node *node) | |
711 | { | |
712 | return ((unsigned long) node) & REMOVED_FLAG; | |
713 | } | |
714 | ||
715 | static | |
716 | struct cds_lfht_node *flag_removed(struct cds_lfht_node *node) | |
717 | { | |
718 | return (struct cds_lfht_node *) (((unsigned long) node) | REMOVED_FLAG); | |
719 | } | |
720 | ||
721 | static | |
722 | int is_dummy(struct cds_lfht_node *node) | |
723 | { | |
724 | return ((unsigned long) node) & DUMMY_FLAG; | |
725 | } | |
726 | ||
727 | static | |
728 | struct cds_lfht_node *flag_dummy(struct cds_lfht_node *node) | |
729 | { | |
730 | return (struct cds_lfht_node *) (((unsigned long) node) | DUMMY_FLAG); | |
731 | } | |
732 | ||
733 | static | |
734 | struct cds_lfht_node *get_end(void) | |
735 | { | |
736 | return (struct cds_lfht_node *) END_VALUE; | |
737 | } | |
738 | ||
739 | static | |
740 | int is_end(struct cds_lfht_node *node) | |
741 | { | |
742 | return clear_flag(node) == (struct cds_lfht_node *) END_VALUE; | |
743 | } | |
744 | ||
745 | static | |
746 | unsigned long _uatomic_max(unsigned long *ptr, unsigned long v) | |
747 | { | |
748 | unsigned long old1, old2; | |
749 | ||
750 | old1 = uatomic_read(ptr); | |
751 | do { | |
752 | old2 = old1; | |
753 | if (old2 >= v) | |
754 | return old2; | |
755 | } while ((old1 = uatomic_cmpxchg(ptr, old2, v)) != old2); | |
756 | return v; | |
757 | } | |
758 | ||
759 | static | |
d6b18934 DG |
760 | struct _cds_lfht_node *lookup_bucket(struct cds_lfht *ht, unsigned long size, |
761 | unsigned long hash) | |
fa68aa62 | 762 | { |
d6b18934 DG |
763 | unsigned long index, order; |
764 | ||
765 | assert(size > 0); | |
766 | index = hash & (size - 1); | |
767 | ||
768 | if (index < ht->min_alloc_size) { | |
769 | dbg_printf("lookup hash %lu index %lu order 0 aridx 0\n", | |
770 | hash, index); | |
771 | return &ht->t.tbl[0]->nodes[index]; | |
772 | } | |
773 | /* | |
774 | * equivalent to get_count_order_ulong(index + 1), but optimizes | |
775 | * away the non-existing 0 special-case for | |
776 | * get_count_order_ulong. | |
777 | */ | |
778 | order = fls_ulong(index); | |
779 | dbg_printf("lookup hash %lu index %lu order %lu aridx %lu\n", | |
780 | hash, index, order, index & ((1UL << (order - 1)) - 1)); | |
781 | return &ht->t.tbl[order]->nodes[index & ((1UL << (order - 1)) - 1)]; | |
fa68aa62 MD |
782 | } |
783 | ||
784 | /* | |
785 | * Remove all logically deleted nodes from a bucket up to a certain node key. | |
786 | */ | |
787 | static | |
788 | void _cds_lfht_gc_bucket(struct cds_lfht_node *dummy, struct cds_lfht_node *node) | |
789 | { | |
790 | struct cds_lfht_node *iter_prev, *iter, *next, *new_next; | |
791 | ||
792 | assert(!is_dummy(dummy)); | |
793 | assert(!is_removed(dummy)); | |
794 | assert(!is_dummy(node)); | |
795 | assert(!is_removed(node)); | |
796 | for (;;) { | |
797 | iter_prev = dummy; | |
798 | /* We can always skip the dummy node initially */ | |
799 | iter = rcu_dereference(iter_prev->p.next); | |
d6b18934 | 800 | assert(!is_removed(iter)); |
fa68aa62 MD |
801 | assert(iter_prev->p.reverse_hash <= node->p.reverse_hash); |
802 | /* | |
803 | * We should never be called with dummy (start of chain) | |
804 | * and logically removed node (end of path compression | |
805 | * marker) being the actual same node. This would be a | |
806 | * bug in the algorithm implementation. | |
807 | */ | |
808 | assert(dummy != node); | |
809 | for (;;) { | |
6e59ae26 | 810 | if (caa_unlikely(is_end(iter))) |
fa68aa62 | 811 | return; |
6e59ae26 | 812 | if (caa_likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash)) |
fa68aa62 MD |
813 | return; |
814 | next = rcu_dereference(clear_flag(iter)->p.next); | |
6e59ae26 | 815 | if (caa_likely(is_removed(next))) |
fa68aa62 MD |
816 | break; |
817 | iter_prev = clear_flag(iter); | |
818 | iter = next; | |
819 | } | |
820 | assert(!is_removed(iter)); | |
821 | if (is_dummy(iter)) | |
822 | new_next = flag_dummy(clear_flag(next)); | |
823 | else | |
824 | new_next = clear_flag(next); | |
fa68aa62 MD |
825 | (void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next); |
826 | } | |
827 | return; | |
828 | } | |
829 | ||
830 | static | |
831 | int _cds_lfht_replace(struct cds_lfht *ht, unsigned long size, | |
832 | struct cds_lfht_node *old_node, | |
d6b18934 | 833 | struct cds_lfht_node *old_next, |
fa68aa62 MD |
834 | struct cds_lfht_node *new_node) |
835 | { | |
d6b18934 | 836 | struct cds_lfht_node *dummy, *ret_next; |
fa68aa62 | 837 | struct _cds_lfht_node *lookup; |
fa68aa62 MD |
838 | |
839 | if (!old_node) /* Return -ENOENT if asked to replace NULL node */ | |
d6b18934 | 840 | return -ENOENT; |
fa68aa62 MD |
841 | |
842 | assert(!is_removed(old_node)); | |
843 | assert(!is_dummy(old_node)); | |
844 | assert(!is_removed(new_node)); | |
845 | assert(!is_dummy(new_node)); | |
846 | assert(new_node != old_node); | |
d6b18934 | 847 | for (;;) { |
fa68aa62 | 848 | /* Insert after node to be replaced */ |
fa68aa62 MD |
849 | if (is_removed(old_next)) { |
850 | /* | |
851 | * Too late, the old node has been removed under us | |
852 | * between lookup and replace. Fail. | |
853 | */ | |
d6b18934 | 854 | return -ENOENT; |
fa68aa62 MD |
855 | } |
856 | assert(!is_dummy(old_next)); | |
857 | assert(new_node != clear_flag(old_next)); | |
858 | new_node->p.next = clear_flag(old_next); | |
859 | /* | |
860 | * Here is the whole trick for lock-free replace: we add | |
861 | * the replacement node _after_ the node we want to | |
862 | * replace by atomically setting its next pointer at the | |
863 | * same time we set its removal flag. Given that | |
864 | * the lookups/get next use an iterator aware of the | |
865 | * next pointer, they will either skip the old node due | |
866 | * to the removal flag and see the new node, or use | |
867 | * the old node, but will not see the new one. | |
868 | */ | |
869 | ret_next = uatomic_cmpxchg(&old_node->p.next, | |
870 | old_next, flag_removed(new_node)); | |
d6b18934 DG |
871 | if (ret_next == old_next) |
872 | break; /* We performed the replacement. */ | |
873 | old_next = ret_next; | |
874 | } | |
fa68aa62 MD |
875 | |
876 | /* | |
877 | * Ensure that the old node is not visible to readers anymore: | |
878 | * lookup for the node, and remove it (along with any other | |
879 | * logically removed node) if found. | |
880 | */ | |
d6b18934 | 881 | lookup = lookup_bucket(ht, size, bit_reverse_ulong(old_node->p.reverse_hash)); |
fa68aa62 MD |
882 | dummy = (struct cds_lfht_node *) lookup; |
883 | _cds_lfht_gc_bucket(dummy, new_node); | |
d6b18934 DG |
884 | |
885 | assert(is_removed(rcu_dereference(old_node->p.next))); | |
886 | return 0; | |
fa68aa62 MD |
887 | } |
888 | ||
d6b18934 DG |
889 | /* |
890 | * A non-NULL unique_ret pointer uses the "add unique" (or uniquify) add | |
891 | * mode. A NULL unique_ret allows creation of duplicate keys. | |
892 | */ | |
fa68aa62 | 893 | static |
d6b18934 DG |
894 | void _cds_lfht_add(struct cds_lfht *ht, |
895 | unsigned long size, | |
896 | struct cds_lfht_node *node, | |
897 | struct cds_lfht_iter *unique_ret, | |
898 | int dummy) | |
fa68aa62 MD |
899 | { |
900 | struct cds_lfht_node *iter_prev, *iter, *next, *new_node, *new_next, | |
d6b18934 | 901 | *return_node; |
fa68aa62 | 902 | struct _cds_lfht_node *lookup; |
fa68aa62 MD |
903 | |
904 | assert(!is_dummy(node)); | |
905 | assert(!is_removed(node)); | |
d6b18934 | 906 | lookup = lookup_bucket(ht, size, bit_reverse_ulong(node->p.reverse_hash)); |
fa68aa62 MD |
907 | for (;;) { |
908 | uint32_t chain_len = 0; | |
909 | ||
910 | /* | |
911 | * iter_prev points to the non-removed node prior to the | |
912 | * insert location. | |
913 | */ | |
fa68aa62 MD |
914 | iter_prev = (struct cds_lfht_node *) lookup; |
915 | /* We can always skip the dummy node initially */ | |
916 | iter = rcu_dereference(iter_prev->p.next); | |
917 | assert(iter_prev->p.reverse_hash <= node->p.reverse_hash); | |
918 | for (;;) { | |
6e59ae26 | 919 | if (caa_unlikely(is_end(iter))) |
fa68aa62 | 920 | goto insert; |
6e59ae26 | 921 | if (caa_likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash)) |
fa68aa62 | 922 | goto insert; |
d6b18934 DG |
923 | |
924 | /* dummy node is the first node of the identical-hash-value chain */ | |
925 | if (dummy && clear_flag(iter)->p.reverse_hash == node->p.reverse_hash) | |
926 | goto insert; | |
927 | ||
fa68aa62 | 928 | next = rcu_dereference(clear_flag(iter)->p.next); |
6e59ae26 | 929 | if (caa_unlikely(is_removed(next))) |
fa68aa62 | 930 | goto gc_node; |
d6b18934 DG |
931 | |
932 | /* uniquely add */ | |
933 | if (unique_ret | |
fa68aa62 | 934 | && !is_dummy(next) |
d6b18934 DG |
935 | && clear_flag(iter)->p.reverse_hash == node->p.reverse_hash) { |
936 | struct cds_lfht_iter d_iter = { .node = node, .next = iter, }; | |
937 | ||
938 | /* | |
939 | * uniquely adding inserts the node as the first | |
940 | * node of the identical-hash-value node chain. | |
941 | * | |
942 | * This semantic ensures no duplicated keys | |
943 | * should ever be observable in the table | |
944 | * (including observe one node by one node | |
945 | * by forward iterations) | |
946 | */ | |
947 | cds_lfht_next_duplicate(ht, &d_iter); | |
948 | if (!d_iter.node) | |
949 | goto insert; | |
950 | ||
951 | *unique_ret = d_iter; | |
952 | return; | |
fa68aa62 | 953 | } |
d6b18934 | 954 | |
fa68aa62 MD |
955 | /* Only account for identical reverse hash once */ |
956 | if (iter_prev->p.reverse_hash != clear_flag(iter)->p.reverse_hash | |
957 | && !is_dummy(next)) | |
958 | check_resize(ht, size, ++chain_len); | |
959 | iter_prev = clear_flag(iter); | |
960 | iter = next; | |
961 | } | |
962 | ||
963 | insert: | |
964 | assert(node != clear_flag(iter)); | |
965 | assert(!is_removed(iter_prev)); | |
966 | assert(!is_removed(iter)); | |
967 | assert(iter_prev != node); | |
968 | if (!dummy) | |
969 | node->p.next = clear_flag(iter); | |
970 | else | |
971 | node->p.next = flag_dummy(clear_flag(iter)); | |
972 | if (is_dummy(iter)) | |
973 | new_node = flag_dummy(node); | |
974 | else | |
975 | new_node = node; | |
976 | if (uatomic_cmpxchg(&iter_prev->p.next, iter, | |
977 | new_node) != iter) { | |
978 | continue; /* retry */ | |
979 | } else { | |
d6b18934 DG |
980 | return_node = node; |
981 | goto end; | |
fa68aa62 MD |
982 | } |
983 | ||
984 | gc_node: | |
985 | assert(!is_removed(iter)); | |
986 | if (is_dummy(iter)) | |
987 | new_next = flag_dummy(clear_flag(next)); | |
988 | else | |
989 | new_next = clear_flag(next); | |
990 | (void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next); | |
991 | /* retry */ | |
992 | } | |
fa68aa62 | 993 | end: |
d6b18934 DG |
994 | if (unique_ret) { |
995 | unique_ret->node = return_node; | |
996 | /* unique_ret->next left unset, never used. */ | |
997 | } | |
fa68aa62 MD |
998 | } |
999 | ||
1000 | static | |
1001 | int _cds_lfht_del(struct cds_lfht *ht, unsigned long size, | |
1002 | struct cds_lfht_node *node, | |
1003 | int dummy_removal) | |
1004 | { | |
1005 | struct cds_lfht_node *dummy, *next, *old; | |
1006 | struct _cds_lfht_node *lookup; | |
fa68aa62 MD |
1007 | |
1008 | if (!node) /* Return -ENOENT if asked to delete NULL node */ | |
d6b18934 | 1009 | return -ENOENT; |
fa68aa62 MD |
1010 | |
1011 | /* logically delete the node */ | |
1012 | assert(!is_dummy(node)); | |
1013 | assert(!is_removed(node)); | |
1014 | old = rcu_dereference(node->p.next); | |
1015 | do { | |
1016 | struct cds_lfht_node *new_next; | |
1017 | ||
1018 | next = old; | |
6e59ae26 | 1019 | if (caa_unlikely(is_removed(next))) |
d6b18934 | 1020 | return -ENOENT; |
fa68aa62 MD |
1021 | if (dummy_removal) |
1022 | assert(is_dummy(next)); | |
1023 | else | |
1024 | assert(!is_dummy(next)); | |
1025 | new_next = flag_removed(next); | |
1026 | old = uatomic_cmpxchg(&node->p.next, next, new_next); | |
1027 | } while (old != next); | |
fa68aa62 | 1028 | /* We performed the (logical) deletion. */ |
fa68aa62 MD |
1029 | |
1030 | /* | |
1031 | * Ensure that the node is not visible to readers anymore: lookup for | |
1032 | * the node, and remove it (along with any other logically removed node) | |
1033 | * if found. | |
1034 | */ | |
d6b18934 | 1035 | lookup = lookup_bucket(ht, size, bit_reverse_ulong(node->p.reverse_hash)); |
fa68aa62 MD |
1036 | dummy = (struct cds_lfht_node *) lookup; |
1037 | _cds_lfht_gc_bucket(dummy, node); | |
d6b18934 DG |
1038 | |
1039 | assert(is_removed(rcu_dereference(node->p.next))); | |
1040 | return 0; | |
fa68aa62 MD |
1041 | } |
1042 | ||
1043 | static | |
1044 | void *partition_resize_thread(void *arg) | |
1045 | { | |
1046 | struct partition_resize_work *work = arg; | |
1047 | ||
1048 | work->ht->cds_lfht_rcu_register_thread(); | |
1049 | work->fct(work->ht, work->i, work->start, work->len); | |
1050 | work->ht->cds_lfht_rcu_unregister_thread(); | |
1051 | return NULL; | |
1052 | } | |
1053 | ||
1054 | static | |
1055 | void partition_resize_helper(struct cds_lfht *ht, unsigned long i, | |
1056 | unsigned long len, | |
1057 | void (*fct)(struct cds_lfht *ht, unsigned long i, | |
1058 | unsigned long start, unsigned long len)) | |
1059 | { | |
1060 | unsigned long partition_len; | |
1061 | struct partition_resize_work *work; | |
1062 | int thread, ret; | |
1063 | unsigned long nr_threads; | |
fa68aa62 MD |
1064 | |
1065 | /* | |
1066 | * Note: nr_cpus_mask + 1 is always power of 2. | |
1067 | * We spawn just the number of threads we need to satisfy the minimum | |
1068 | * partition size, up to the number of CPUs in the system. | |
1069 | */ | |
f6a9efaa DG |
1070 | if (nr_cpus_mask > 0) { |
1071 | nr_threads = min(nr_cpus_mask + 1, | |
1072 | len >> MIN_PARTITION_PER_THREAD_ORDER); | |
1073 | } else { | |
1074 | nr_threads = 1; | |
1075 | } | |
fa68aa62 MD |
1076 | partition_len = len >> get_count_order_ulong(nr_threads); |
1077 | work = calloc(nr_threads, sizeof(*work)); | |
fa68aa62 MD |
1078 | assert(work); |
1079 | for (thread = 0; thread < nr_threads; thread++) { | |
1080 | work[thread].ht = ht; | |
1081 | work[thread].i = i; | |
1082 | work[thread].len = partition_len; | |
1083 | work[thread].start = thread * partition_len; | |
1084 | work[thread].fct = fct; | |
d6b18934 | 1085 | ret = pthread_create(&(work[thread].thread_id), ht->resize_attr, |
fa68aa62 MD |
1086 | partition_resize_thread, &work[thread]); |
1087 | assert(!ret); | |
1088 | } | |
1089 | for (thread = 0; thread < nr_threads; thread++) { | |
d6b18934 | 1090 | ret = pthread_join(work[thread].thread_id, NULL); |
fa68aa62 MD |
1091 | assert(!ret); |
1092 | } | |
1093 | free(work); | |
fa68aa62 MD |
1094 | } |
1095 | ||
1096 | /* | |
1097 | * Holding RCU read lock to protect _cds_lfht_add against memory | |
1098 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
1099 | * problem). | |
1100 | * | |
1101 | * When we reach a certain length, we can split this population phase over | |
1102 | * many worker threads, based on the number of CPUs available in the system. | |
1103 | * This should therefore take care of not having the expand lagging behind too | |
1104 | * many concurrent insertion threads by using the scheduler's ability to | |
1105 | * schedule dummy node population fairly with insertions. | |
1106 | */ | |
1107 | static | |
1108 | void init_table_populate_partition(struct cds_lfht *ht, unsigned long i, | |
1109 | unsigned long start, unsigned long len) | |
1110 | { | |
1111 | unsigned long j; | |
1112 | ||
d6b18934 | 1113 | assert(i > ht->min_alloc_order); |
fa68aa62 MD |
1114 | ht->cds_lfht_rcu_read_lock(); |
1115 | for (j = start; j < start + len; j++) { | |
1116 | struct cds_lfht_node *new_node = | |
1117 | (struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j]; | |
1118 | ||
1119 | dbg_printf("init populate: i %lu j %lu hash %lu\n", | |
d6b18934 | 1120 | i, j, (1UL << (i - 1)) + j); |
fa68aa62 | 1121 | new_node->p.reverse_hash = |
d6b18934 DG |
1122 | bit_reverse_ulong((1UL << (i - 1)) + j); |
1123 | _cds_lfht_add(ht, 1UL << (i - 1), | |
1124 | new_node, NULL, 1); | |
fa68aa62 MD |
1125 | } |
1126 | ht->cds_lfht_rcu_read_unlock(); | |
1127 | } | |
1128 | ||
1129 | static | |
1130 | void init_table_populate(struct cds_lfht *ht, unsigned long i, | |
1131 | unsigned long len) | |
1132 | { | |
1133 | assert(nr_cpus_mask != -1); | |
1134 | if (nr_cpus_mask < 0 || len < 2 * MIN_PARTITION_PER_THREAD) { | |
1135 | ht->cds_lfht_rcu_thread_online(); | |
1136 | init_table_populate_partition(ht, i, 0, len); | |
1137 | ht->cds_lfht_rcu_thread_offline(); | |
1138 | return; | |
1139 | } | |
1140 | partition_resize_helper(ht, i, len, init_table_populate_partition); | |
1141 | } | |
1142 | ||
1143 | static | |
1144 | void init_table(struct cds_lfht *ht, | |
d6b18934 | 1145 | unsigned long first_order, unsigned long last_order) |
fa68aa62 | 1146 | { |
d6b18934 | 1147 | unsigned long i; |
fa68aa62 | 1148 | |
d6b18934 DG |
1149 | dbg_printf("init table: first_order %lu last_order %lu\n", |
1150 | first_order, last_order); | |
1151 | assert(first_order > ht->min_alloc_order); | |
1152 | for (i = first_order; i <= last_order; i++) { | |
fa68aa62 MD |
1153 | unsigned long len; |
1154 | ||
d6b18934 | 1155 | len = 1UL << (i - 1); |
fa68aa62 MD |
1156 | dbg_printf("init order %lu len: %lu\n", i, len); |
1157 | ||
1158 | /* Stop expand if the resize target changes under us */ | |
d6b18934 | 1159 | if (CMM_LOAD_SHARED(ht->t.resize_target) < (1UL << i)) |
fa68aa62 MD |
1160 | break; |
1161 | ||
d6b18934 | 1162 | ht->t.tbl[i] = calloc(1, len * sizeof(struct _cds_lfht_node)); |
fa68aa62 MD |
1163 | assert(ht->t.tbl[i]); |
1164 | ||
1165 | /* | |
1166 | * Set all dummy nodes reverse hash values for a level and | |
1167 | * link all dummy nodes into the table. | |
1168 | */ | |
1169 | init_table_populate(ht, i, len); | |
1170 | ||
1171 | /* | |
1172 | * Update table size. | |
1173 | */ | |
1174 | cmm_smp_wmb(); /* populate data before RCU size */ | |
d6b18934 | 1175 | CMM_STORE_SHARED(ht->t.size, 1UL << i); |
fa68aa62 | 1176 | |
d6b18934 | 1177 | dbg_printf("init new size: %lu\n", 1UL << i); |
fa68aa62 MD |
1178 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
1179 | break; | |
1180 | } | |
1181 | } | |
1182 | ||
1183 | /* | |
1184 | * Holding RCU read lock to protect _cds_lfht_remove against memory | |
1185 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
1186 | * problem). | |
1187 | * For a single level, we logically remove and garbage collect each node. | |
1188 | * | |
1189 | * As a design choice, we perform logical removal and garbage collection on a | |
1190 | * node-per-node basis to simplify this algorithm. We also assume keeping good | |
1191 | * cache locality of the operation would overweight possible performance gain | |
1192 | * that could be achieved by batching garbage collection for multiple levels. | |
1193 | * However, this would have to be justified by benchmarks. | |
1194 | * | |
1195 | * Concurrent removal and add operations are helping us perform garbage | |
1196 | * collection of logically removed nodes. We guarantee that all logically | |
1197 | * removed nodes have been garbage-collected (unlinked) before call_rcu is | |
1198 | * invoked to free a hole level of dummy nodes (after a grace period). | |
1199 | * | |
1200 | * Logical removal and garbage collection can therefore be done in batch or on a | |
1201 | * node-per-node basis, as long as the guarantee above holds. | |
1202 | * | |
1203 | * When we reach a certain length, we can split this removal over many worker | |
1204 | * threads, based on the number of CPUs available in the system. This should | |
1205 | * take care of not letting resize process lag behind too many concurrent | |
1206 | * updater threads actively inserting into the hash table. | |
1207 | */ | |
1208 | static | |
1209 | void remove_table_partition(struct cds_lfht *ht, unsigned long i, | |
1210 | unsigned long start, unsigned long len) | |
1211 | { | |
1212 | unsigned long j; | |
1213 | ||
d6b18934 | 1214 | assert(i > ht->min_alloc_order); |
fa68aa62 MD |
1215 | ht->cds_lfht_rcu_read_lock(); |
1216 | for (j = start; j < start + len; j++) { | |
1217 | struct cds_lfht_node *fini_node = | |
1218 | (struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j]; | |
1219 | ||
1220 | dbg_printf("remove entry: i %lu j %lu hash %lu\n", | |
d6b18934 | 1221 | i, j, (1UL << (i - 1)) + j); |
fa68aa62 | 1222 | fini_node->p.reverse_hash = |
d6b18934 DG |
1223 | bit_reverse_ulong((1UL << (i - 1)) + j); |
1224 | (void) _cds_lfht_del(ht, 1UL << (i - 1), fini_node, 1); | |
fa68aa62 MD |
1225 | } |
1226 | ht->cds_lfht_rcu_read_unlock(); | |
1227 | } | |
1228 | ||
1229 | static | |
1230 | void remove_table(struct cds_lfht *ht, unsigned long i, unsigned long len) | |
1231 | { | |
1232 | ||
1233 | assert(nr_cpus_mask != -1); | |
1234 | if (nr_cpus_mask < 0 || len < 2 * MIN_PARTITION_PER_THREAD) { | |
1235 | ht->cds_lfht_rcu_thread_online(); | |
1236 | remove_table_partition(ht, i, 0, len); | |
1237 | ht->cds_lfht_rcu_thread_offline(); | |
1238 | return; | |
1239 | } | |
1240 | partition_resize_helper(ht, i, len, remove_table_partition); | |
1241 | } | |
1242 | ||
1243 | static | |
1244 | void fini_table(struct cds_lfht *ht, | |
d6b18934 | 1245 | unsigned long first_order, unsigned long last_order) |
fa68aa62 | 1246 | { |
d6b18934 DG |
1247 | long i; |
1248 | void *free_by_rcu = NULL; | |
fa68aa62 | 1249 | |
d6b18934 DG |
1250 | dbg_printf("fini table: first_order %lu last_order %lu\n", |
1251 | first_order, last_order); | |
1252 | assert(first_order > ht->min_alloc_order); | |
1253 | for (i = last_order; i >= first_order; i--) { | |
fa68aa62 MD |
1254 | unsigned long len; |
1255 | ||
d6b18934 | 1256 | len = 1UL << (i - 1); |
fa68aa62 MD |
1257 | dbg_printf("fini order %lu len: %lu\n", i, len); |
1258 | ||
1259 | /* Stop shrink if the resize target changes under us */ | |
1260 | if (CMM_LOAD_SHARED(ht->t.resize_target) > (1UL << (i - 1))) | |
1261 | break; | |
1262 | ||
1263 | cmm_smp_wmb(); /* populate data before RCU size */ | |
1264 | CMM_STORE_SHARED(ht->t.size, 1UL << (i - 1)); | |
1265 | ||
1266 | /* | |
1267 | * We need to wait for all add operations to reach Q.S. (and | |
1268 | * thus use the new table for lookups) before we can start | |
1269 | * releasing the old dummy nodes. Otherwise their lookup will | |
1270 | * return a logically removed node as insert position. | |
1271 | */ | |
1272 | ht->cds_lfht_synchronize_rcu(); | |
d6b18934 DG |
1273 | if (free_by_rcu) |
1274 | free(free_by_rcu); | |
fa68aa62 MD |
1275 | |
1276 | /* | |
1277 | * Set "removed" flag in dummy nodes about to be removed. | |
1278 | * Unlink all now-logically-removed dummy node pointers. | |
1279 | * Concurrent add/remove operation are helping us doing | |
1280 | * the gc. | |
1281 | */ | |
1282 | remove_table(ht, i, len); | |
1283 | ||
d6b18934 | 1284 | free_by_rcu = ht->t.tbl[i]; |
fa68aa62 MD |
1285 | |
1286 | dbg_printf("fini new size: %lu\n", 1UL << i); | |
1287 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
1288 | break; | |
1289 | } | |
d6b18934 DG |
1290 | |
1291 | if (free_by_rcu) { | |
1292 | ht->cds_lfht_synchronize_rcu(); | |
1293 | free(free_by_rcu); | |
1294 | } | |
1295 | } | |
1296 | ||
1297 | static | |
1298 | void cds_lfht_create_dummy(struct cds_lfht *ht, unsigned long size) | |
1299 | { | |
1300 | struct _cds_lfht_node *prev, *node; | |
1301 | unsigned long order, len, i, j; | |
1302 | ||
1303 | ht->t.tbl[0] = calloc(1, ht->min_alloc_size * sizeof(struct _cds_lfht_node)); | |
1304 | assert(ht->t.tbl[0]); | |
1305 | ||
1306 | dbg_printf("create dummy: order %lu index %lu hash %lu\n", 0, 0, 0); | |
1307 | ht->t.tbl[0]->nodes[0].next = flag_dummy(get_end()); | |
1308 | ht->t.tbl[0]->nodes[0].reverse_hash = 0; | |
1309 | ||
1310 | for (order = 1; order < get_count_order_ulong(size) + 1; order++) { | |
1311 | len = 1UL << (order - 1); | |
1312 | if (order <= ht->min_alloc_order) { | |
1313 | ht->t.tbl[order] = (struct rcu_level *) (ht->t.tbl[0]->nodes + len); | |
1314 | } else { | |
1315 | ht->t.tbl[order] = calloc(1, len * sizeof(struct _cds_lfht_node)); | |
1316 | assert(ht->t.tbl[order]); | |
1317 | } | |
1318 | ||
1319 | i = 0; | |
1320 | prev = ht->t.tbl[i]->nodes; | |
1321 | for (j = 0; j < len; j++) { | |
1322 | if (j & (j - 1)) { /* Between power of 2 */ | |
1323 | prev++; | |
1324 | } else if (j) { /* At each power of 2 */ | |
1325 | i++; | |
1326 | prev = ht->t.tbl[i]->nodes; | |
1327 | } | |
1328 | ||
1329 | node = &ht->t.tbl[order]->nodes[j]; | |
1330 | dbg_printf("create dummy: order %lu index %lu hash %lu\n", | |
1331 | order, j, j + len); | |
1332 | node->next = prev->next; | |
1333 | assert(is_dummy(node->next)); | |
1334 | node->reverse_hash = bit_reverse_ulong(j + len); | |
1335 | prev->next = flag_dummy((struct cds_lfht_node *)node); | |
1336 | } | |
1337 | } | |
fa68aa62 MD |
1338 | } |
1339 | ||
1340 | struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct, | |
1341 | cds_lfht_compare_fct compare_fct, | |
1342 | unsigned long hash_seed, | |
1343 | unsigned long init_size, | |
d6b18934 | 1344 | unsigned long min_alloc_size, |
fa68aa62 MD |
1345 | int flags, |
1346 | void (*cds_lfht_call_rcu)(struct rcu_head *head, | |
1347 | void (*func)(struct rcu_head *head)), | |
1348 | void (*cds_lfht_synchronize_rcu)(void), | |
1349 | void (*cds_lfht_rcu_read_lock)(void), | |
1350 | void (*cds_lfht_rcu_read_unlock)(void), | |
1351 | void (*cds_lfht_rcu_thread_offline)(void), | |
1352 | void (*cds_lfht_rcu_thread_online)(void), | |
1353 | void (*cds_lfht_rcu_register_thread)(void), | |
1354 | void (*cds_lfht_rcu_unregister_thread)(void), | |
1355 | pthread_attr_t *attr) | |
1356 | { | |
1357 | struct cds_lfht *ht; | |
1358 | unsigned long order; | |
1359 | ||
d6b18934 DG |
1360 | /* min_alloc_size must be power of two */ |
1361 | if (!min_alloc_size || (min_alloc_size & (min_alloc_size - 1))) | |
1362 | return NULL; | |
fa68aa62 | 1363 | /* init_size must be power of two */ |
d6b18934 | 1364 | if (!init_size || (init_size & (init_size - 1))) |
fa68aa62 | 1365 | return NULL; |
d6b18934 DG |
1366 | min_alloc_size = max(min_alloc_size, MIN_TABLE_SIZE); |
1367 | init_size = max(init_size, min_alloc_size); | |
fa68aa62 MD |
1368 | ht = calloc(1, sizeof(struct cds_lfht)); |
1369 | assert(ht); | |
d6b18934 | 1370 | ht->flags = flags; |
fa68aa62 MD |
1371 | ht->hash_fct = hash_fct; |
1372 | ht->compare_fct = compare_fct; | |
1373 | ht->hash_seed = hash_seed; | |
1374 | ht->cds_lfht_call_rcu = cds_lfht_call_rcu; | |
1375 | ht->cds_lfht_synchronize_rcu = cds_lfht_synchronize_rcu; | |
1376 | ht->cds_lfht_rcu_read_lock = cds_lfht_rcu_read_lock; | |
1377 | ht->cds_lfht_rcu_read_unlock = cds_lfht_rcu_read_unlock; | |
1378 | ht->cds_lfht_rcu_thread_offline = cds_lfht_rcu_thread_offline; | |
1379 | ht->cds_lfht_rcu_thread_online = cds_lfht_rcu_thread_online; | |
1380 | ht->cds_lfht_rcu_register_thread = cds_lfht_rcu_register_thread; | |
1381 | ht->cds_lfht_rcu_unregister_thread = cds_lfht_rcu_unregister_thread; | |
1382 | ht->resize_attr = attr; | |
d6b18934 | 1383 | alloc_split_items_count(ht); |
fa68aa62 MD |
1384 | /* this mutex should not nest in read-side C.S. */ |
1385 | pthread_mutex_init(&ht->resize_mutex, NULL); | |
d6b18934 DG |
1386 | order = get_count_order_ulong(init_size); |
1387 | ht->t.resize_target = 1UL << order; | |
1388 | ht->min_alloc_size = min_alloc_size; | |
1389 | ht->min_alloc_order = get_count_order_ulong(min_alloc_size); | |
1390 | cds_lfht_create_dummy(ht, 1UL << order); | |
1391 | ht->t.size = 1UL << order; | |
fa68aa62 MD |
1392 | return ht; |
1393 | } | |
1394 | ||
1395 | void cds_lfht_lookup(struct cds_lfht *ht, void *key, size_t key_len, | |
1396 | struct cds_lfht_iter *iter) | |
1397 | { | |
1398 | struct cds_lfht_node *node, *next, *dummy_node; | |
1399 | struct _cds_lfht_node *lookup; | |
d6b18934 | 1400 | unsigned long hash, reverse_hash, size; |
fa68aa62 MD |
1401 | |
1402 | hash = ht->hash_fct(key, key_len, ht->hash_seed); | |
1403 | reverse_hash = bit_reverse_ulong(hash); | |
1404 | ||
1405 | size = rcu_dereference(ht->t.size); | |
d6b18934 | 1406 | lookup = lookup_bucket(ht, size, hash); |
fa68aa62 MD |
1407 | dummy_node = (struct cds_lfht_node *) lookup; |
1408 | /* We can always skip the dummy node initially */ | |
1409 | node = rcu_dereference(dummy_node->p.next); | |
1410 | node = clear_flag(node); | |
1411 | for (;;) { | |
6e59ae26 | 1412 | if (caa_unlikely(is_end(node))) { |
fa68aa62 MD |
1413 | node = next = NULL; |
1414 | break; | |
1415 | } | |
6e59ae26 | 1416 | if (caa_unlikely(node->p.reverse_hash > reverse_hash)) { |
fa68aa62 MD |
1417 | node = next = NULL; |
1418 | break; | |
1419 | } | |
1420 | next = rcu_dereference(node->p.next); | |
d6b18934 | 1421 | assert(node == clear_flag(node)); |
6e59ae26 | 1422 | if (caa_likely(!is_removed(next)) |
fa68aa62 | 1423 | && !is_dummy(next) |
d6b18934 | 1424 | && node->p.reverse_hash == reverse_hash |
6e59ae26 | 1425 | && caa_likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) { |
fa68aa62 MD |
1426 | break; |
1427 | } | |
1428 | node = clear_flag(next); | |
1429 | } | |
1430 | assert(!node || !is_dummy(rcu_dereference(node->p.next))); | |
1431 | iter->node = node; | |
1432 | iter->next = next; | |
1433 | } | |
1434 | ||
f6a9efaa | 1435 | void cds_lfht_next_duplicate(struct cds_lfht *ht, struct cds_lfht_iter *iter) |
fa68aa62 MD |
1436 | { |
1437 | struct cds_lfht_node *node, *next; | |
1438 | unsigned long reverse_hash; | |
1439 | void *key; | |
1440 | size_t key_len; | |
1441 | ||
1442 | node = iter->node; | |
1443 | reverse_hash = node->p.reverse_hash; | |
1444 | key = node->key; | |
1445 | key_len = node->key_len; | |
1446 | next = iter->next; | |
1447 | node = clear_flag(next); | |
1448 | ||
1449 | for (;;) { | |
6e59ae26 | 1450 | if (caa_unlikely(is_end(node))) { |
fa68aa62 MD |
1451 | node = next = NULL; |
1452 | break; | |
1453 | } | |
6e59ae26 | 1454 | if (caa_unlikely(node->p.reverse_hash > reverse_hash)) { |
fa68aa62 MD |
1455 | node = next = NULL; |
1456 | break; | |
1457 | } | |
1458 | next = rcu_dereference(node->p.next); | |
6e59ae26 | 1459 | if (caa_likely(!is_removed(next)) |
fa68aa62 | 1460 | && !is_dummy(next) |
6e59ae26 | 1461 | && caa_likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) { |
fa68aa62 MD |
1462 | break; |
1463 | } | |
1464 | node = clear_flag(next); | |
1465 | } | |
1466 | assert(!node || !is_dummy(rcu_dereference(node->p.next))); | |
1467 | iter->node = node; | |
1468 | iter->next = next; | |
1469 | } | |
1470 | ||
f6a9efaa DG |
1471 | void cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_iter *iter) |
1472 | { | |
1473 | struct cds_lfht_node *node, *next; | |
1474 | ||
1475 | node = clear_flag(iter->next); | |
1476 | for (;;) { | |
6e59ae26 | 1477 | if (caa_unlikely(is_end(node))) { |
f6a9efaa DG |
1478 | node = next = NULL; |
1479 | break; | |
1480 | } | |
1481 | next = rcu_dereference(node->p.next); | |
6e59ae26 | 1482 | if (caa_likely(!is_removed(next)) |
f6a9efaa DG |
1483 | && !is_dummy(next)) { |
1484 | break; | |
1485 | } | |
1486 | node = clear_flag(next); | |
1487 | } | |
1488 | assert(!node || !is_dummy(rcu_dereference(node->p.next))); | |
1489 | iter->node = node; | |
1490 | iter->next = next; | |
1491 | } | |
1492 | ||
1493 | void cds_lfht_first(struct cds_lfht *ht, struct cds_lfht_iter *iter) | |
1494 | { | |
1495 | struct _cds_lfht_node *lookup; | |
1496 | ||
1497 | /* | |
1498 | * Get next after first dummy node. The first dummy node is the | |
1499 | * first node of the linked list. | |
1500 | */ | |
1501 | lookup = &ht->t.tbl[0]->nodes[0]; | |
1502 | iter->next = lookup->next; | |
1503 | cds_lfht_next(ht, iter); | |
1504 | } | |
1505 | ||
fa68aa62 MD |
1506 | void cds_lfht_add(struct cds_lfht *ht, struct cds_lfht_node *node) |
1507 | { | |
1508 | unsigned long hash, size; | |
1509 | ||
1510 | hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed); | |
1511 | node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash); | |
1512 | ||
1513 | size = rcu_dereference(ht->t.size); | |
d6b18934 DG |
1514 | _cds_lfht_add(ht, size, node, NULL, 0); |
1515 | ht_count_add(ht, size, hash); | |
fa68aa62 MD |
1516 | } |
1517 | ||
1518 | struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, | |
1519 | struct cds_lfht_node *node) | |
1520 | { | |
1521 | unsigned long hash, size; | |
d6b18934 | 1522 | struct cds_lfht_iter iter; |
fa68aa62 MD |
1523 | |
1524 | hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed); | |
1525 | node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash); | |
1526 | ||
1527 | size = rcu_dereference(ht->t.size); | |
d6b18934 DG |
1528 | _cds_lfht_add(ht, size, node, &iter, 0); |
1529 | if (iter.node == node) | |
1530 | ht_count_add(ht, size, hash); | |
1531 | return iter.node; | |
fa68aa62 MD |
1532 | } |
1533 | ||
1534 | struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht, | |
1535 | struct cds_lfht_node *node) | |
1536 | { | |
1537 | unsigned long hash, size; | |
d6b18934 | 1538 | struct cds_lfht_iter iter; |
fa68aa62 MD |
1539 | |
1540 | hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed); | |
1541 | node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash); | |
1542 | ||
1543 | size = rcu_dereference(ht->t.size); | |
d6b18934 DG |
1544 | for (;;) { |
1545 | _cds_lfht_add(ht, size, node, &iter, 0); | |
1546 | if (iter.node == node) { | |
1547 | ht_count_add(ht, size, hash); | |
1548 | return NULL; | |
1549 | } | |
1550 | ||
1551 | if (!_cds_lfht_replace(ht, size, iter.node, iter.next, node)) | |
1552 | return iter.node; | |
1553 | } | |
fa68aa62 MD |
1554 | } |
1555 | ||
1556 | int cds_lfht_replace(struct cds_lfht *ht, struct cds_lfht_iter *old_iter, | |
1557 | struct cds_lfht_node *new_node) | |
1558 | { | |
1559 | unsigned long size; | |
1560 | ||
1561 | size = rcu_dereference(ht->t.size); | |
1562 | return _cds_lfht_replace(ht, size, old_iter->node, old_iter->next, | |
1563 | new_node); | |
1564 | } | |
1565 | ||
1566 | int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_iter *iter) | |
1567 | { | |
d6b18934 | 1568 | unsigned long size, hash; |
fa68aa62 MD |
1569 | int ret; |
1570 | ||
1571 | size = rcu_dereference(ht->t.size); | |
1572 | ret = _cds_lfht_del(ht, size, iter->node, 0); | |
d6b18934 DG |
1573 | if (!ret) { |
1574 | hash = bit_reverse_ulong(iter->node->p.reverse_hash); | |
1575 | ht_count_del(ht, size, hash); | |
1576 | } | |
fa68aa62 MD |
1577 | return ret; |
1578 | } | |
1579 | ||
1580 | static | |
1581 | int cds_lfht_delete_dummy(struct cds_lfht *ht) | |
1582 | { | |
1583 | struct cds_lfht_node *node; | |
1584 | struct _cds_lfht_node *lookup; | |
1585 | unsigned long order, i, size; | |
1586 | ||
1587 | /* Check that the table is empty */ | |
1588 | lookup = &ht->t.tbl[0]->nodes[0]; | |
1589 | node = (struct cds_lfht_node *) lookup; | |
1590 | do { | |
1591 | node = clear_flag(node)->p.next; | |
1592 | if (!is_dummy(node)) | |
1593 | return -EPERM; | |
1594 | assert(!is_removed(node)); | |
1595 | } while (!is_end(node)); | |
1596 | /* | |
1597 | * size accessed without rcu_dereference because hash table is | |
1598 | * being destroyed. | |
1599 | */ | |
1600 | size = ht->t.size; | |
1601 | /* Internal sanity check: all nodes left should be dummy */ | |
1602 | for (order = 0; order < get_count_order_ulong(size) + 1; order++) { | |
1603 | unsigned long len; | |
1604 | ||
1605 | len = !order ? 1 : 1UL << (order - 1); | |
1606 | for (i = 0; i < len; i++) { | |
1607 | dbg_printf("delete order %lu i %lu hash %lu\n", | |
1608 | order, i, | |
1609 | bit_reverse_ulong(ht->t.tbl[order]->nodes[i].reverse_hash)); | |
1610 | assert(is_dummy(ht->t.tbl[order]->nodes[i].next)); | |
1611 | } | |
d6b18934 DG |
1612 | |
1613 | if (order == ht->min_alloc_order) | |
1614 | poison_free(ht->t.tbl[0]); | |
1615 | else if (order > ht->min_alloc_order) | |
1616 | poison_free(ht->t.tbl[order]); | |
1617 | /* Nothing to delete for order < ht->min_alloc_order */ | |
fa68aa62 MD |
1618 | } |
1619 | return 0; | |
1620 | } | |
1621 | ||
1622 | /* | |
1623 | * Should only be called when no more concurrent readers nor writers can | |
1624 | * possibly access the table. | |
1625 | */ | |
1626 | int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr) | |
1627 | { | |
1628 | int ret; | |
1629 | ||
1630 | /* Wait for in-flight resize operations to complete */ | |
d6b18934 DG |
1631 | _CMM_STORE_SHARED(ht->in_progress_destroy, 1); |
1632 | cmm_smp_mb(); /* Store destroy before load resize */ | |
fa68aa62 MD |
1633 | while (uatomic_read(&ht->in_progress_resize)) |
1634 | poll(NULL, 0, 100); /* wait for 100ms */ | |
1635 | ret = cds_lfht_delete_dummy(ht); | |
1636 | if (ret) | |
1637 | return ret; | |
d6b18934 | 1638 | free_split_items_count(ht); |
fa68aa62 MD |
1639 | if (attr) |
1640 | *attr = ht->resize_attr; | |
1641 | poison_free(ht); | |
1642 | return ret; | |
1643 | } | |
1644 | ||
1645 | void cds_lfht_count_nodes(struct cds_lfht *ht, | |
1646 | long *approx_before, | |
1647 | unsigned long *count, | |
1648 | unsigned long *removed, | |
1649 | long *approx_after) | |
1650 | { | |
1651 | struct cds_lfht_node *node, *next; | |
1652 | struct _cds_lfht_node *lookup; | |
1653 | unsigned long nr_dummy = 0; | |
1654 | ||
1655 | *approx_before = 0; | |
d6b18934 | 1656 | if (ht->split_count) { |
fa68aa62 MD |
1657 | int i; |
1658 | ||
d6b18934 DG |
1659 | for (i = 0; i < split_count_mask + 1; i++) { |
1660 | *approx_before += uatomic_read(&ht->split_count[i].add); | |
1661 | *approx_before -= uatomic_read(&ht->split_count[i].del); | |
fa68aa62 MD |
1662 | } |
1663 | } | |
1664 | ||
1665 | *count = 0; | |
1666 | *removed = 0; | |
1667 | ||
1668 | /* Count non-dummy nodes in the table */ | |
1669 | lookup = &ht->t.tbl[0]->nodes[0]; | |
1670 | node = (struct cds_lfht_node *) lookup; | |
1671 | do { | |
1672 | next = rcu_dereference(node->p.next); | |
1673 | if (is_removed(next)) { | |
1674 | if (!is_dummy(next)) | |
1675 | (*removed)++; | |
1676 | else | |
1677 | (nr_dummy)++; | |
1678 | } else if (!is_dummy(next)) | |
1679 | (*count)++; | |
1680 | else | |
1681 | (nr_dummy)++; | |
1682 | node = clear_flag(next); | |
1683 | } while (!is_end(node)); | |
1684 | dbg_printf("number of dummy nodes: %lu\n", nr_dummy); | |
1685 | *approx_after = 0; | |
d6b18934 | 1686 | if (ht->split_count) { |
fa68aa62 MD |
1687 | int i; |
1688 | ||
d6b18934 DG |
1689 | for (i = 0; i < split_count_mask + 1; i++) { |
1690 | *approx_after += uatomic_read(&ht->split_count[i].add); | |
1691 | *approx_after -= uatomic_read(&ht->split_count[i].del); | |
fa68aa62 MD |
1692 | } |
1693 | } | |
1694 | } | |
1695 | ||
1696 | /* called with resize mutex held */ | |
1697 | static | |
1698 | void _do_cds_lfht_grow(struct cds_lfht *ht, | |
1699 | unsigned long old_size, unsigned long new_size) | |
1700 | { | |
1701 | unsigned long old_order, new_order; | |
1702 | ||
d6b18934 DG |
1703 | old_order = get_count_order_ulong(old_size); |
1704 | new_order = get_count_order_ulong(new_size); | |
1705 | dbg_printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", | |
1706 | old_size, old_order, new_size, new_order); | |
fa68aa62 | 1707 | assert(new_size > old_size); |
d6b18934 | 1708 | init_table(ht, old_order + 1, new_order); |
fa68aa62 MD |
1709 | } |
1710 | ||
1711 | /* called with resize mutex held */ | |
1712 | static | |
1713 | void _do_cds_lfht_shrink(struct cds_lfht *ht, | |
1714 | unsigned long old_size, unsigned long new_size) | |
1715 | { | |
1716 | unsigned long old_order, new_order; | |
1717 | ||
d6b18934 DG |
1718 | new_size = max(new_size, ht->min_alloc_size); |
1719 | old_order = get_count_order_ulong(old_size); | |
1720 | new_order = get_count_order_ulong(new_size); | |
1721 | dbg_printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", | |
1722 | old_size, old_order, new_size, new_order); | |
fa68aa62 MD |
1723 | assert(new_size < old_size); |
1724 | ||
1725 | /* Remove and unlink all dummy nodes to remove. */ | |
d6b18934 | 1726 | fini_table(ht, new_order + 1, old_order); |
fa68aa62 MD |
1727 | } |
1728 | ||
1729 | ||
1730 | /* called with resize mutex held */ | |
1731 | static | |
1732 | void _do_cds_lfht_resize(struct cds_lfht *ht) | |
1733 | { | |
1734 | unsigned long new_size, old_size; | |
1735 | ||
1736 | /* | |
1737 | * Resize table, re-do if the target size has changed under us. | |
1738 | */ | |
1739 | do { | |
d6b18934 DG |
1740 | assert(uatomic_read(&ht->in_progress_resize)); |
1741 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
1742 | break; | |
fa68aa62 MD |
1743 | ht->t.resize_initiated = 1; |
1744 | old_size = ht->t.size; | |
1745 | new_size = CMM_LOAD_SHARED(ht->t.resize_target); | |
1746 | if (old_size < new_size) | |
1747 | _do_cds_lfht_grow(ht, old_size, new_size); | |
1748 | else if (old_size > new_size) | |
1749 | _do_cds_lfht_shrink(ht, old_size, new_size); | |
1750 | ht->t.resize_initiated = 0; | |
1751 | /* write resize_initiated before read resize_target */ | |
1752 | cmm_smp_mb(); | |
1753 | } while (ht->t.size != CMM_LOAD_SHARED(ht->t.resize_target)); | |
1754 | } | |
1755 | ||
1756 | static | |
1757 | unsigned long resize_target_update(struct cds_lfht *ht, unsigned long size, | |
1758 | int growth_order) | |
1759 | { | |
1760 | return _uatomic_max(&ht->t.resize_target, | |
1761 | size << growth_order); | |
1762 | } | |
1763 | ||
1764 | static | |
1765 | void resize_target_update_count(struct cds_lfht *ht, | |
1766 | unsigned long count) | |
1767 | { | |
d6b18934 | 1768 | count = max(count, ht->min_alloc_size); |
fa68aa62 MD |
1769 | uatomic_set(&ht->t.resize_target, count); |
1770 | } | |
1771 | ||
1772 | void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size) | |
1773 | { | |
1774 | resize_target_update_count(ht, new_size); | |
1775 | CMM_STORE_SHARED(ht->t.resize_initiated, 1); | |
1776 | ht->cds_lfht_rcu_thread_offline(); | |
1777 | pthread_mutex_lock(&ht->resize_mutex); | |
1778 | _do_cds_lfht_resize(ht); | |
1779 | pthread_mutex_unlock(&ht->resize_mutex); | |
1780 | ht->cds_lfht_rcu_thread_online(); | |
1781 | } | |
1782 | ||
1783 | static | |
1784 | void do_resize_cb(struct rcu_head *head) | |
1785 | { | |
1786 | struct rcu_resize_work *work = | |
1787 | caa_container_of(head, struct rcu_resize_work, head); | |
1788 | struct cds_lfht *ht = work->ht; | |
1789 | ||
1790 | ht->cds_lfht_rcu_thread_offline(); | |
1791 | pthread_mutex_lock(&ht->resize_mutex); | |
1792 | _do_cds_lfht_resize(ht); | |
1793 | pthread_mutex_unlock(&ht->resize_mutex); | |
1794 | ht->cds_lfht_rcu_thread_online(); | |
1795 | poison_free(work); | |
1796 | cmm_smp_mb(); /* finish resize before decrement */ | |
1797 | uatomic_dec(&ht->in_progress_resize); | |
1798 | } | |
1799 | ||
1800 | static | |
1801 | void cds_lfht_resize_lazy(struct cds_lfht *ht, unsigned long size, int growth) | |
1802 | { | |
1803 | struct rcu_resize_work *work; | |
1804 | unsigned long target_size; | |
1805 | ||
1806 | target_size = resize_target_update(ht, size, growth); | |
1807 | /* Store resize_target before read resize_initiated */ | |
1808 | cmm_smp_mb(); | |
1809 | if (!CMM_LOAD_SHARED(ht->t.resize_initiated) && size < target_size) { | |
1810 | uatomic_inc(&ht->in_progress_resize); | |
d6b18934 DG |
1811 | cmm_smp_mb(); /* increment resize count before load destroy */ |
1812 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) { | |
1813 | uatomic_dec(&ht->in_progress_resize); | |
1814 | return; | |
1815 | } | |
fa68aa62 MD |
1816 | work = malloc(sizeof(*work)); |
1817 | work->ht = ht; | |
1818 | ht->cds_lfht_call_rcu(&work->head, do_resize_cb); | |
1819 | CMM_STORE_SHARED(ht->t.resize_initiated, 1); | |
1820 | } | |
1821 | } | |
1822 | ||
fa68aa62 MD |
1823 | static |
1824 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, | |
1825 | unsigned long count) | |
1826 | { | |
1827 | struct rcu_resize_work *work; | |
1828 | ||
1829 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) | |
1830 | return; | |
1831 | resize_target_update_count(ht, count); | |
1832 | /* Store resize_target before read resize_initiated */ | |
1833 | cmm_smp_mb(); | |
1834 | if (!CMM_LOAD_SHARED(ht->t.resize_initiated)) { | |
1835 | uatomic_inc(&ht->in_progress_resize); | |
d6b18934 DG |
1836 | cmm_smp_mb(); /* increment resize count before load destroy */ |
1837 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) { | |
1838 | uatomic_dec(&ht->in_progress_resize); | |
1839 | return; | |
1840 | } | |
fa68aa62 MD |
1841 | work = malloc(sizeof(*work)); |
1842 | work->ht = ht; | |
1843 | ht->cds_lfht_call_rcu(&work->head, do_resize_cb); | |
1844 | CMM_STORE_SHARED(ht->t.resize_initiated, 1); | |
1845 | } | |
1846 | } |