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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> | |
bec39940 | 7 | * Copyright 2011 - Lai Jiangshan <laijs@cn.fujitsu.com> |
fa68aa62 MD |
8 | * |
9 | * This library is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU Lesser General Public | |
11 | * License as published by the Free Software Foundation; either | |
12 | * version 2.1 of the License, or (at your option) any later version. | |
13 | * | |
14 | * This library is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | * Lesser General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU Lesser General Public | |
20 | * License along with this library; if not, write to the Free Software | |
21 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
22 | */ | |
23 | ||
24 | /* | |
25 | * Based on the following articles: | |
26 | * - Ori Shalev and Nir Shavit. Split-ordered lists: Lock-free | |
27 | * extensible hash tables. J. ACM 53, 3 (May 2006), 379-405. | |
28 | * - Michael, M. M. High performance dynamic lock-free hash tables | |
29 | * and list-based sets. In Proceedings of the fourteenth annual ACM | |
30 | * symposium on Parallel algorithms and architectures, ACM Press, | |
31 | * (2002), 73-82. | |
32 | * | |
33 | * Some specificities of this Lock-Free Resizable RCU Hash Table | |
34 | * implementation: | |
35 | * | |
36 | * - RCU read-side critical section allows readers to perform hash | |
37 | * table lookups and use the returned objects safely by delaying | |
38 | * memory reclaim of a grace period. | |
39 | * - Add and remove operations are lock-free, and do not need to | |
40 | * allocate memory. They need to be executed within RCU read-side | |
41 | * critical section to ensure the objects they read are valid and to | |
42 | * deal with the cmpxchg ABA problem. | |
43 | * - add and add_unique operations are supported. add_unique checks if | |
44 | * the node key already exists in the hash table. It ensures no key | |
45 | * duplicata exists. | |
46 | * - The resize operation executes concurrently with add/remove/lookup. | |
47 | * - Hash table nodes are contained within a split-ordered list. This | |
48 | * list is ordered by incrementing reversed-bits-hash value. | |
bec39940 | 49 | * - An index of bucket nodes is kept. These bucket nodes are the hash |
fa68aa62 MD |
50 | * table "buckets", and they are also chained together in the |
51 | * split-ordered list, which allows recursive expansion. | |
52 | * - The resize operation for small tables only allows expanding the hash table. | |
53 | * It is triggered automatically by detecting long chains in the add | |
54 | * operation. | |
55 | * - The resize operation for larger tables (and available through an | |
56 | * API) allows both expanding and shrinking the hash table. | |
d6b18934 | 57 | * - Split-counters are used to keep track of the number of |
fa68aa62 MD |
58 | * nodes within the hash table for automatic resize triggering. |
59 | * - Resize operation initiated by long chain detection is executed by a | |
60 | * call_rcu thread, which keeps lock-freedom of add and remove. | |
61 | * - Resize operations are protected by a mutex. | |
62 | * - The removal operation is split in two parts: first, a "removed" | |
63 | * flag is set in the next pointer within the node to remove. Then, | |
64 | * a "garbage collection" is performed in the bucket containing the | |
65 | * removed node (from the start of the bucket up to the removed node). | |
66 | * All encountered nodes with "removed" flag set in their next | |
67 | * pointers are removed from the linked-list. If the cmpxchg used for | |
68 | * removal fails (due to concurrent garbage-collection or concurrent | |
69 | * add), we retry from the beginning of the bucket. This ensures that | |
70 | * the node with "removed" flag set is removed from the hash table | |
71 | * (not visible to lookups anymore) before the RCU read-side critical | |
72 | * section held across removal ends. Furthermore, this ensures that | |
73 | * the node with "removed" flag set is removed from the linked-list | |
74 | * before its memory is reclaimed. Only the thread which removal | |
75 | * successfully set the "removed" flag (with a cmpxchg) into a node's | |
76 | * next pointer is considered to have succeeded its removal (and thus | |
77 | * owns the node to reclaim). Because we garbage-collect starting from | |
bec39940 | 78 | * an invariant node (the start-of-bucket bucket node) up to the |
fa68aa62 MD |
79 | * "removed" node (or find a reverse-hash that is higher), we are sure |
80 | * that a successful traversal of the chain leads to a chain that is | |
81 | * present in the linked-list (the start node is never removed) and | |
82 | * that is does not contain the "removed" node anymore, even if | |
83 | * concurrent delete/add operations are changing the structure of the | |
84 | * list concurrently. | |
85 | * - The add operation performs gargage collection of buckets if it | |
86 | * encounters nodes with removed flag set in the bucket where it wants | |
87 | * to add its new node. This ensures lock-freedom of add operation by | |
88 | * helping the remover unlink nodes from the list rather than to wait | |
89 | * for it do to so. | |
90 | * - A RCU "order table" indexed by log2(hash index) is copied and | |
91 | * expanded by the resize operation. This order table allows finding | |
bec39940 DG |
92 | * the "bucket node" tables. |
93 | * - There is one bucket node table per hash index order. The size of | |
94 | * each bucket node table is half the number of hashes contained in | |
d6b18934 | 95 | * this order (except for order 0). |
bec39940 DG |
96 | * - synchronzie_rcu is used to garbage-collect the old bucket node table. |
97 | * - The per-order bucket node tables contain a compact version of the | |
fa68aa62 MD |
98 | * hash table nodes. These tables are invariant after they are |
99 | * populated into the hash table. | |
d6b18934 | 100 | * |
bec39940 | 101 | * Bucket node tables: |
d6b18934 | 102 | * |
bec39940 DG |
103 | * hash table hash table the last all bucket node tables |
104 | * order size bucket node 0 1 2 3 4 5 6(index) | |
d6b18934 DG |
105 | * table size |
106 | * 0 1 1 1 | |
107 | * 1 2 1 1 1 | |
108 | * 2 4 2 1 1 2 | |
109 | * 3 8 4 1 1 2 4 | |
110 | * 4 16 8 1 1 2 4 8 | |
111 | * 5 32 16 1 1 2 4 8 16 | |
112 | * 6 64 32 1 1 2 4 8 16 32 | |
113 | * | |
bec39940 | 114 | * When growing/shrinking, we only focus on the last bucket node table |
d6b18934 DG |
115 | * which size is (!order ? 1 : (1 << (order -1))). |
116 | * | |
117 | * Example for growing/shrinking: | |
bec39940 DG |
118 | * grow hash table from order 5 to 6: init the index=6 bucket node table |
119 | * shrink hash table from order 6 to 5: fini the index=6 bucket node table | |
d6b18934 | 120 | * |
fa68aa62 | 121 | * A bit of ascii art explanation: |
bec39940 DG |
122 | * |
123 | * Order index is the off-by-one compare to the actual power of 2 because | |
fa68aa62 | 124 | * we use index 0 to deal with the 0 special-case. |
bec39940 | 125 | * |
fa68aa62 | 126 | * This shows the nodes for a small table ordered by reversed bits: |
bec39940 | 127 | * |
fa68aa62 MD |
128 | * bits reverse |
129 | * 0 000 000 | |
130 | * 4 100 001 | |
131 | * 2 010 010 | |
132 | * 6 110 011 | |
133 | * 1 001 100 | |
134 | * 5 101 101 | |
135 | * 3 011 110 | |
136 | * 7 111 111 | |
bec39940 DG |
137 | * |
138 | * This shows the nodes in order of non-reversed bits, linked by | |
fa68aa62 | 139 | * reversed-bit order. |
bec39940 | 140 | * |
fa68aa62 MD |
141 | * order bits reverse |
142 | * 0 0 000 000 | |
d6b18934 DG |
143 | * 1 | 1 001 100 <- |
144 | * 2 | | 2 010 010 <- | | |
fa68aa62 | 145 | * | | | 3 011 110 | <- | |
fa68aa62 MD |
146 | * 3 -> | | | 4 100 001 | | |
147 | * -> | | 5 101 101 | | |
148 | * -> | 6 110 011 | |
149 | * -> 7 111 111 | |
150 | */ | |
151 | ||
152 | #define _LGPL_SOURCE | |
153 | #include <stdlib.h> | |
154 | #include <errno.h> | |
155 | #include <assert.h> | |
156 | #include <stdio.h> | |
157 | #include <stdint.h> | |
158 | #include <string.h> | |
159 | ||
d6b18934 | 160 | #include "config.h" |
fa68aa62 MD |
161 | #include <urcu.h> |
162 | #include <urcu-call-rcu.h> | |
163 | #include <urcu/arch.h> | |
164 | #include <urcu/uatomic.h> | |
165 | #include <urcu/compiler.h> | |
fa68aa62 MD |
166 | #include <stdio.h> |
167 | #include <pthread.h> | |
168 | ||
f6a9efaa | 169 | #include "rculfhash.h" |
bec39940 DG |
170 | #include "rculfhash-internal.h" |
171 | #include "urcu-flavor.h" | |
fa68aa62 | 172 | |
9ef70f87 MD |
173 | /* |
174 | * We need to lock pthread exit, which deadlocks __nptl_setxid in the | |
175 | * runas clone. | |
176 | * This work-around will be allowed to be removed when runas.c gets | |
177 | * changed to do an exec() before issuing seteuid/setegid. | |
178 | * See http://sourceware.org/bugzilla/show_bug.cgi?id=10184 for details. | |
179 | */ | |
180 | pthread_mutex_t lttng_libc_state_lock = PTHREAD_MUTEX_INITIALIZER; | |
181 | ||
fa68aa62 | 182 | /* |
d6b18934 | 183 | * Split-counters lazily update the global counter each 1024 |
fa68aa62 MD |
184 | * addition/removal. It automatically keeps track of resize required. |
185 | * We use the bucket length as indicator for need to expand for small | |
186 | * tables and machines lacking per-cpu data suppport. | |
187 | */ | |
188 | #define COUNT_COMMIT_ORDER 10 | |
d6b18934 | 189 | #define DEFAULT_SPLIT_COUNT_MASK 0xFUL |
fa68aa62 MD |
190 | #define CHAIN_LEN_TARGET 1 |
191 | #define CHAIN_LEN_RESIZE_THRESHOLD 3 | |
192 | ||
193 | /* | |
194 | * Define the minimum table size. | |
195 | */ | |
bec39940 DG |
196 | #define MIN_TABLE_ORDER 0 |
197 | #define MIN_TABLE_SIZE (1UL << MIN_TABLE_ORDER) | |
fa68aa62 MD |
198 | |
199 | /* | |
bec39940 | 200 | * Minimum number of bucket nodes to touch per thread to parallelize grow/shrink. |
fa68aa62 MD |
201 | */ |
202 | #define MIN_PARTITION_PER_THREAD_ORDER 12 | |
203 | #define MIN_PARTITION_PER_THREAD (1UL << MIN_PARTITION_PER_THREAD_ORDER) | |
204 | ||
fa68aa62 MD |
205 | /* |
206 | * The removed flag needs to be updated atomically with the pointer. | |
207 | * It indicates that no node must attach to the node scheduled for | |
208 | * removal, and that node garbage collection must be performed. | |
bec39940 | 209 | * The bucket flag does not require to be updated atomically with the |
fa68aa62 MD |
210 | * pointer, but it is added as a pointer low bit flag to save space. |
211 | */ | |
212 | #define REMOVED_FLAG (1UL << 0) | |
bec39940 DG |
213 | #define BUCKET_FLAG (1UL << 1) |
214 | #define REMOVAL_OWNER_FLAG (1UL << 2) | |
215 | #define FLAGS_MASK ((1UL << 3) - 1) | |
fa68aa62 MD |
216 | |
217 | /* Value of the end pointer. Should not interact with flags. */ | |
218 | #define END_VALUE NULL | |
219 | ||
bec39940 DG |
220 | DEFINE_RCU_FLAVOR(rcu_flavor); |
221 | ||
d6b18934 DG |
222 | /* |
223 | * ht_items_count: Split-counters counting the number of node addition | |
224 | * and removal in the table. Only used if the CDS_LFHT_ACCOUNTING flag | |
225 | * is set at hash table creation. | |
226 | * | |
227 | * These are free-running counters, never reset to zero. They count the | |
228 | * number of add/remove, and trigger every (1 << COUNT_COMMIT_ORDER) | |
229 | * operations to update the global counter. We choose a power-of-2 value | |
230 | * for the trigger to deal with 32 or 64-bit overflow of the counter. | |
231 | */ | |
fa68aa62 MD |
232 | struct ht_items_count { |
233 | unsigned long add, del; | |
234 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); | |
235 | ||
d6b18934 DG |
236 | /* |
237 | * rcu_resize_work: Contains arguments passed to RCU worker thread | |
238 | * responsible for performing lazy resize. | |
239 | */ | |
fa68aa62 MD |
240 | struct rcu_resize_work { |
241 | struct rcu_head head; | |
242 | struct cds_lfht *ht; | |
243 | }; | |
244 | ||
d6b18934 DG |
245 | /* |
246 | * partition_resize_work: Contains arguments passed to worker threads | |
247 | * executing the hash table resize on partitions of the hash table | |
248 | * assigned to each processor's worker thread. | |
249 | */ | |
fa68aa62 | 250 | struct partition_resize_work { |
d6b18934 | 251 | pthread_t thread_id; |
fa68aa62 MD |
252 | struct cds_lfht *ht; |
253 | unsigned long i, start, len; | |
254 | void (*fct)(struct cds_lfht *ht, unsigned long i, | |
255 | unsigned long start, unsigned long len); | |
256 | }; | |
257 | ||
fa68aa62 MD |
258 | /* |
259 | * Algorithm to reverse bits in a word by lookup table, extended to | |
260 | * 64-bit words. | |
261 | * Source: | |
262 | * http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable | |
263 | * Originally from Public Domain. | |
264 | */ | |
265 | ||
bec39940 | 266 | static const uint8_t BitReverseTable256[256] = |
fa68aa62 MD |
267 | { |
268 | #define R2(n) (n), (n) + 2*64, (n) + 1*64, (n) + 3*64 | |
269 | #define R4(n) R2(n), R2((n) + 2*16), R2((n) + 1*16), R2((n) + 3*16) | |
270 | #define R6(n) R4(n), R4((n) + 2*4 ), R4((n) + 1*4 ), R4((n) + 3*4 ) | |
271 | R6(0), R6(2), R6(1), R6(3) | |
272 | }; | |
273 | #undef R2 | |
274 | #undef R4 | |
275 | #undef R6 | |
276 | ||
277 | static | |
278 | uint8_t bit_reverse_u8(uint8_t v) | |
279 | { | |
280 | return BitReverseTable256[v]; | |
281 | } | |
282 | ||
283 | static __attribute__((unused)) | |
284 | uint32_t bit_reverse_u32(uint32_t v) | |
285 | { | |
bec39940 DG |
286 | return ((uint32_t) bit_reverse_u8(v) << 24) | |
287 | ((uint32_t) bit_reverse_u8(v >> 8) << 16) | | |
288 | ((uint32_t) bit_reverse_u8(v >> 16) << 8) | | |
fa68aa62 MD |
289 | ((uint32_t) bit_reverse_u8(v >> 24)); |
290 | } | |
291 | ||
292 | static __attribute__((unused)) | |
293 | uint64_t bit_reverse_u64(uint64_t v) | |
294 | { | |
bec39940 DG |
295 | return ((uint64_t) bit_reverse_u8(v) << 56) | |
296 | ((uint64_t) bit_reverse_u8(v >> 8) << 48) | | |
fa68aa62 MD |
297 | ((uint64_t) bit_reverse_u8(v >> 16) << 40) | |
298 | ((uint64_t) bit_reverse_u8(v >> 24) << 32) | | |
bec39940 DG |
299 | ((uint64_t) bit_reverse_u8(v >> 32) << 24) | |
300 | ((uint64_t) bit_reverse_u8(v >> 40) << 16) | | |
fa68aa62 MD |
301 | ((uint64_t) bit_reverse_u8(v >> 48) << 8) | |
302 | ((uint64_t) bit_reverse_u8(v >> 56)); | |
303 | } | |
304 | ||
305 | static | |
306 | unsigned long bit_reverse_ulong(unsigned long v) | |
307 | { | |
308 | #if (CAA_BITS_PER_LONG == 32) | |
309 | return bit_reverse_u32(v); | |
310 | #else | |
311 | return bit_reverse_u64(v); | |
312 | #endif | |
313 | } | |
314 | ||
315 | /* | |
316 | * fls: returns the position of the most significant bit. | |
317 | * Returns 0 if no bit is set, else returns the position of the most | |
318 | * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit). | |
319 | */ | |
320 | #if defined(__i386) || defined(__x86_64) | |
321 | static inline | |
322 | unsigned int fls_u32(uint32_t x) | |
323 | { | |
324 | int r; | |
325 | ||
326 | asm("bsrl %1,%0\n\t" | |
327 | "jnz 1f\n\t" | |
328 | "movl $-1,%0\n\t" | |
329 | "1:\n\t" | |
330 | : "=r" (r) : "rm" (x)); | |
331 | return r + 1; | |
332 | } | |
333 | #define HAS_FLS_U32 | |
334 | #endif | |
335 | ||
336 | #if defined(__x86_64) | |
337 | static inline | |
338 | unsigned int fls_u64(uint64_t x) | |
339 | { | |
340 | long r; | |
341 | ||
342 | asm("bsrq %1,%0\n\t" | |
343 | "jnz 1f\n\t" | |
344 | "movq $-1,%0\n\t" | |
345 | "1:\n\t" | |
346 | : "=r" (r) : "rm" (x)); | |
347 | return r + 1; | |
348 | } | |
349 | #define HAS_FLS_U64 | |
350 | #endif | |
351 | ||
352 | #ifndef HAS_FLS_U64 | |
353 | static __attribute__((unused)) | |
354 | unsigned int fls_u64(uint64_t x) | |
355 | { | |
356 | unsigned int r = 64; | |
357 | ||
358 | if (!x) | |
359 | return 0; | |
360 | ||
361 | if (!(x & 0xFFFFFFFF00000000ULL)) { | |
362 | x <<= 32; | |
363 | r -= 32; | |
364 | } | |
365 | if (!(x & 0xFFFF000000000000ULL)) { | |
366 | x <<= 16; | |
367 | r -= 16; | |
368 | } | |
369 | if (!(x & 0xFF00000000000000ULL)) { | |
370 | x <<= 8; | |
371 | r -= 8; | |
372 | } | |
373 | if (!(x & 0xF000000000000000ULL)) { | |
374 | x <<= 4; | |
375 | r -= 4; | |
376 | } | |
377 | if (!(x & 0xC000000000000000ULL)) { | |
378 | x <<= 2; | |
379 | r -= 2; | |
380 | } | |
381 | if (!(x & 0x8000000000000000ULL)) { | |
382 | x <<= 1; | |
383 | r -= 1; | |
384 | } | |
385 | return r; | |
386 | } | |
387 | #endif | |
388 | ||
389 | #ifndef HAS_FLS_U32 | |
390 | static __attribute__((unused)) | |
391 | unsigned int fls_u32(uint32_t x) | |
392 | { | |
393 | unsigned int r = 32; | |
394 | ||
395 | if (!x) | |
396 | return 0; | |
397 | if (!(x & 0xFFFF0000U)) { | |
398 | x <<= 16; | |
399 | r -= 16; | |
400 | } | |
401 | if (!(x & 0xFF000000U)) { | |
402 | x <<= 8; | |
403 | r -= 8; | |
404 | } | |
405 | if (!(x & 0xF0000000U)) { | |
406 | x <<= 4; | |
407 | r -= 4; | |
408 | } | |
409 | if (!(x & 0xC0000000U)) { | |
410 | x <<= 2; | |
411 | r -= 2; | |
412 | } | |
413 | if (!(x & 0x80000000U)) { | |
414 | x <<= 1; | |
415 | r -= 1; | |
416 | } | |
417 | return r; | |
418 | } | |
419 | #endif | |
420 | ||
bec39940 | 421 | unsigned int cds_lfht_fls_ulong(unsigned long x) |
fa68aa62 | 422 | { |
d6b18934 | 423 | #if (CAA_BITS_PER_LONG == 32) |
fa68aa62 MD |
424 | return fls_u32(x); |
425 | #else | |
426 | return fls_u64(x); | |
427 | #endif | |
428 | } | |
429 | ||
d6b18934 DG |
430 | /* |
431 | * Return the minimum order for which x <= (1UL << order). | |
432 | * Return -1 if x is 0. | |
433 | */ | |
bec39940 | 434 | int cds_lfht_get_count_order_u32(uint32_t x) |
fa68aa62 | 435 | { |
d6b18934 DG |
436 | if (!x) |
437 | return -1; | |
fa68aa62 | 438 | |
d6b18934 | 439 | return fls_u32(x - 1); |
fa68aa62 MD |
440 | } |
441 | ||
d6b18934 DG |
442 | /* |
443 | * Return the minimum order for which x <= (1UL << order). | |
444 | * Return -1 if x is 0. | |
445 | */ | |
bec39940 | 446 | int cds_lfht_get_count_order_ulong(unsigned long x) |
fa68aa62 | 447 | { |
d6b18934 DG |
448 | if (!x) |
449 | return -1; | |
fa68aa62 | 450 | |
bec39940 | 451 | return cds_lfht_fls_ulong(x - 1); |
fa68aa62 MD |
452 | } |
453 | ||
fa68aa62 | 454 | static |
bec39940 | 455 | void cds_lfht_resize_lazy_grow(struct cds_lfht *ht, unsigned long size, int growth); |
fa68aa62 | 456 | |
fa68aa62 MD |
457 | static |
458 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, | |
459 | unsigned long count); | |
460 | ||
461 | static long nr_cpus_mask = -1; | |
d6b18934 DG |
462 | static long split_count_mask = -1; |
463 | ||
464 | #if defined(HAVE_SYSCONF) | |
465 | static void ht_init_nr_cpus_mask(void) | |
466 | { | |
467 | long maxcpus; | |
468 | ||
469 | maxcpus = sysconf(_SC_NPROCESSORS_CONF); | |
470 | if (maxcpus <= 0) { | |
471 | nr_cpus_mask = -2; | |
472 | return; | |
473 | } | |
474 | /* | |
475 | * round up number of CPUs to next power of two, so we | |
476 | * can use & for modulo. | |
477 | */ | |
bec39940 | 478 | maxcpus = 1UL << cds_lfht_get_count_order_ulong(maxcpus); |
d6b18934 DG |
479 | nr_cpus_mask = maxcpus - 1; |
480 | } | |
481 | #else /* #if defined(HAVE_SYSCONF) */ | |
482 | static void ht_init_nr_cpus_mask(void) | |
483 | { | |
484 | nr_cpus_mask = -2; | |
485 | } | |
486 | #endif /* #else #if defined(HAVE_SYSCONF) */ | |
fa68aa62 MD |
487 | |
488 | static | |
d6b18934 | 489 | void alloc_split_items_count(struct cds_lfht *ht) |
fa68aa62 MD |
490 | { |
491 | struct ht_items_count *count; | |
492 | ||
d6b18934 DG |
493 | if (nr_cpus_mask == -1) { |
494 | ht_init_nr_cpus_mask(); | |
495 | if (nr_cpus_mask < 0) | |
496 | split_count_mask = DEFAULT_SPLIT_COUNT_MASK; | |
497 | else | |
498 | split_count_mask = nr_cpus_mask; | |
fa68aa62 | 499 | } |
d6b18934 DG |
500 | |
501 | assert(split_count_mask >= 0); | |
502 | ||
503 | if (ht->flags & CDS_LFHT_ACCOUNTING) { | |
504 | ht->split_count = calloc(split_count_mask + 1, sizeof(*count)); | |
505 | assert(ht->split_count); | |
506 | } else { | |
507 | ht->split_count = NULL; | |
fa68aa62 MD |
508 | } |
509 | } | |
510 | ||
511 | static | |
d6b18934 | 512 | void free_split_items_count(struct cds_lfht *ht) |
fa68aa62 | 513 | { |
d6b18934 | 514 | poison_free(ht->split_count); |
fa68aa62 MD |
515 | } |
516 | ||
d6b18934 | 517 | #if defined(HAVE_SCHED_GETCPU) |
fa68aa62 | 518 | static |
d6b18934 | 519 | int ht_get_split_count_index(unsigned long hash) |
fa68aa62 MD |
520 | { |
521 | int cpu; | |
522 | ||
d6b18934 | 523 | assert(split_count_mask >= 0); |
fa68aa62 | 524 | cpu = sched_getcpu(); |
6e59ae26 | 525 | if (caa_unlikely(cpu < 0)) |
d6b18934 | 526 | return hash & split_count_mask; |
fa68aa62 | 527 | else |
d6b18934 | 528 | return cpu & split_count_mask; |
fa68aa62 | 529 | } |
d6b18934 DG |
530 | #else /* #if defined(HAVE_SCHED_GETCPU) */ |
531 | static | |
532 | int ht_get_split_count_index(unsigned long hash) | |
533 | { | |
534 | return hash & split_count_mask; | |
535 | } | |
536 | #endif /* #else #if defined(HAVE_SCHED_GETCPU) */ | |
fa68aa62 MD |
537 | |
538 | static | |
d6b18934 | 539 | void ht_count_add(struct cds_lfht *ht, unsigned long size, unsigned long hash) |
fa68aa62 | 540 | { |
d6b18934 DG |
541 | unsigned long split_count; |
542 | int index; | |
bec39940 | 543 | long count; |
fa68aa62 | 544 | |
6e59ae26 | 545 | if (caa_unlikely(!ht->split_count)) |
fa68aa62 | 546 | return; |
d6b18934 DG |
547 | index = ht_get_split_count_index(hash); |
548 | split_count = uatomic_add_return(&ht->split_count[index].add, 1); | |
bec39940 DG |
549 | if (caa_likely(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1))) |
550 | return; | |
551 | /* Only if number of add multiple of 1UL << COUNT_COMMIT_ORDER */ | |
552 | ||
553 | dbg_printf("add split count %lu\n", split_count); | |
554 | count = uatomic_add_return(&ht->count, | |
555 | 1UL << COUNT_COMMIT_ORDER); | |
556 | if (caa_likely(count & (count - 1))) | |
557 | return; | |
558 | /* Only if global count is power of 2 */ | |
559 | ||
560 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) < size) | |
561 | return; | |
562 | dbg_printf("add set global %ld\n", count); | |
563 | cds_lfht_resize_lazy_count(ht, size, | |
564 | count >> (CHAIN_LEN_TARGET - 1)); | |
fa68aa62 MD |
565 | } |
566 | ||
567 | static | |
d6b18934 | 568 | void ht_count_del(struct cds_lfht *ht, unsigned long size, unsigned long hash) |
fa68aa62 | 569 | { |
d6b18934 DG |
570 | unsigned long split_count; |
571 | int index; | |
bec39940 | 572 | long count; |
fa68aa62 | 573 | |
6e59ae26 | 574 | if (caa_unlikely(!ht->split_count)) |
fa68aa62 | 575 | return; |
d6b18934 DG |
576 | index = ht_get_split_count_index(hash); |
577 | split_count = uatomic_add_return(&ht->split_count[index].del, 1); | |
bec39940 DG |
578 | if (caa_likely(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1))) |
579 | return; | |
580 | /* Only if number of deletes multiple of 1UL << COUNT_COMMIT_ORDER */ | |
581 | ||
582 | dbg_printf("del split count %lu\n", split_count); | |
583 | count = uatomic_add_return(&ht->count, | |
584 | -(1UL << COUNT_COMMIT_ORDER)); | |
585 | if (caa_likely(count & (count - 1))) | |
586 | return; | |
587 | /* Only if global count is power of 2 */ | |
588 | ||
589 | if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) >= size) | |
590 | return; | |
591 | dbg_printf("del set global %ld\n", count); | |
592 | /* | |
593 | * Don't shrink table if the number of nodes is below a | |
594 | * certain threshold. | |
595 | */ | |
596 | if (count < (1UL << COUNT_COMMIT_ORDER) * (split_count_mask + 1)) | |
597 | return; | |
598 | cds_lfht_resize_lazy_count(ht, size, | |
599 | count >> (CHAIN_LEN_TARGET - 1)); | |
fa68aa62 MD |
600 | } |
601 | ||
fa68aa62 MD |
602 | static |
603 | void check_resize(struct cds_lfht *ht, unsigned long size, uint32_t chain_len) | |
604 | { | |
605 | unsigned long count; | |
606 | ||
607 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) | |
608 | return; | |
609 | count = uatomic_read(&ht->count); | |
610 | /* | |
611 | * Use bucket-local length for small table expand and for | |
612 | * environments lacking per-cpu data support. | |
613 | */ | |
614 | if (count >= (1UL << COUNT_COMMIT_ORDER)) | |
615 | return; | |
616 | if (chain_len > 100) | |
617 | dbg_printf("WARNING: large chain length: %u.\n", | |
618 | chain_len); | |
619 | if (chain_len >= CHAIN_LEN_RESIZE_THRESHOLD) | |
bec39940 DG |
620 | cds_lfht_resize_lazy_grow(ht, size, |
621 | cds_lfht_get_count_order_u32(chain_len - (CHAIN_LEN_TARGET - 1))); | |
fa68aa62 MD |
622 | } |
623 | ||
624 | static | |
625 | struct cds_lfht_node *clear_flag(struct cds_lfht_node *node) | |
626 | { | |
627 | return (struct cds_lfht_node *) (((unsigned long) node) & ~FLAGS_MASK); | |
628 | } | |
629 | ||
630 | static | |
631 | int is_removed(struct cds_lfht_node *node) | |
632 | { | |
633 | return ((unsigned long) node) & REMOVED_FLAG; | |
634 | } | |
635 | ||
636 | static | |
637 | struct cds_lfht_node *flag_removed(struct cds_lfht_node *node) | |
638 | { | |
639 | return (struct cds_lfht_node *) (((unsigned long) node) | REMOVED_FLAG); | |
640 | } | |
641 | ||
642 | static | |
bec39940 | 643 | int is_bucket(struct cds_lfht_node *node) |
fa68aa62 | 644 | { |
bec39940 | 645 | return ((unsigned long) node) & BUCKET_FLAG; |
fa68aa62 MD |
646 | } |
647 | ||
648 | static | |
bec39940 | 649 | struct cds_lfht_node *flag_bucket(struct cds_lfht_node *node) |
fa68aa62 | 650 | { |
bec39940 DG |
651 | return (struct cds_lfht_node *) (((unsigned long) node) | BUCKET_FLAG); |
652 | } | |
653 | ||
654 | static | |
655 | int is_removal_owner(struct cds_lfht_node *node) | |
656 | { | |
657 | return ((unsigned long) node) & REMOVAL_OWNER_FLAG; | |
658 | } | |
659 | ||
660 | static | |
661 | struct cds_lfht_node *flag_removal_owner(struct cds_lfht_node *node) | |
662 | { | |
663 | return (struct cds_lfht_node *) (((unsigned long) node) | REMOVAL_OWNER_FLAG); | |
fa68aa62 MD |
664 | } |
665 | ||
666 | static | |
667 | struct cds_lfht_node *get_end(void) | |
668 | { | |
669 | return (struct cds_lfht_node *) END_VALUE; | |
670 | } | |
671 | ||
672 | static | |
673 | int is_end(struct cds_lfht_node *node) | |
674 | { | |
675 | return clear_flag(node) == (struct cds_lfht_node *) END_VALUE; | |
676 | } | |
677 | ||
678 | static | |
bec39940 DG |
679 | unsigned long _uatomic_xchg_monotonic_increase(unsigned long *ptr, |
680 | unsigned long v) | |
fa68aa62 MD |
681 | { |
682 | unsigned long old1, old2; | |
683 | ||
684 | old1 = uatomic_read(ptr); | |
685 | do { | |
686 | old2 = old1; | |
687 | if (old2 >= v) | |
688 | return old2; | |
689 | } while ((old1 = uatomic_cmpxchg(ptr, old2, v)) != old2); | |
bec39940 | 690 | return old2; |
fa68aa62 MD |
691 | } |
692 | ||
693 | static | |
bec39940 | 694 | void cds_lfht_alloc_bucket_table(struct cds_lfht *ht, unsigned long order) |
fa68aa62 | 695 | { |
bec39940 DG |
696 | return ht->mm->alloc_bucket_table(ht, order); |
697 | } | |
d6b18934 | 698 | |
bec39940 DG |
699 | /* |
700 | * cds_lfht_free_bucket_table() should be called with decreasing order. | |
701 | * When cds_lfht_free_bucket_table(0) is called, it means the whole | |
702 | * lfht is destroyed. | |
703 | */ | |
704 | static | |
705 | void cds_lfht_free_bucket_table(struct cds_lfht *ht, unsigned long order) | |
706 | { | |
707 | return ht->mm->free_bucket_table(ht, order); | |
708 | } | |
d6b18934 | 709 | |
bec39940 DG |
710 | static inline |
711 | struct cds_lfht_node *bucket_at(struct cds_lfht *ht, unsigned long index) | |
712 | { | |
713 | return ht->bucket_at(ht, index); | |
714 | } | |
715 | ||
716 | static inline | |
717 | struct cds_lfht_node *lookup_bucket(struct cds_lfht *ht, unsigned long size, | |
718 | unsigned long hash) | |
719 | { | |
720 | assert(size > 0); | |
721 | return bucket_at(ht, hash & (size - 1)); | |
fa68aa62 MD |
722 | } |
723 | ||
724 | /* | |
725 | * Remove all logically deleted nodes from a bucket up to a certain node key. | |
726 | */ | |
727 | static | |
bec39940 | 728 | void _cds_lfht_gc_bucket(struct cds_lfht_node *bucket, struct cds_lfht_node *node) |
fa68aa62 MD |
729 | { |
730 | struct cds_lfht_node *iter_prev, *iter, *next, *new_next; | |
731 | ||
bec39940 DG |
732 | assert(!is_bucket(bucket)); |
733 | assert(!is_removed(bucket)); | |
734 | assert(!is_bucket(node)); | |
fa68aa62 MD |
735 | assert(!is_removed(node)); |
736 | for (;;) { | |
bec39940 DG |
737 | iter_prev = bucket; |
738 | /* We can always skip the bucket node initially */ | |
739 | iter = rcu_dereference(iter_prev->next); | |
d6b18934 | 740 | assert(!is_removed(iter)); |
bec39940 | 741 | assert(iter_prev->reverse_hash <= node->reverse_hash); |
fa68aa62 | 742 | /* |
bec39940 | 743 | * We should never be called with bucket (start of chain) |
fa68aa62 MD |
744 | * and logically removed node (end of path compression |
745 | * marker) being the actual same node. This would be a | |
746 | * bug in the algorithm implementation. | |
747 | */ | |
bec39940 | 748 | assert(bucket != node); |
fa68aa62 | 749 | for (;;) { |
6e59ae26 | 750 | if (caa_unlikely(is_end(iter))) |
fa68aa62 | 751 | return; |
bec39940 | 752 | if (caa_likely(clear_flag(iter)->reverse_hash > node->reverse_hash)) |
fa68aa62 | 753 | return; |
bec39940 | 754 | next = rcu_dereference(clear_flag(iter)->next); |
6e59ae26 | 755 | if (caa_likely(is_removed(next))) |
fa68aa62 MD |
756 | break; |
757 | iter_prev = clear_flag(iter); | |
758 | iter = next; | |
759 | } | |
760 | assert(!is_removed(iter)); | |
bec39940 DG |
761 | if (is_bucket(iter)) |
762 | new_next = flag_bucket(clear_flag(next)); | |
fa68aa62 MD |
763 | else |
764 | new_next = clear_flag(next); | |
bec39940 | 765 | (void) uatomic_cmpxchg(&iter_prev->next, iter, new_next); |
fa68aa62 | 766 | } |
fa68aa62 MD |
767 | } |
768 | ||
769 | static | |
770 | int _cds_lfht_replace(struct cds_lfht *ht, unsigned long size, | |
771 | struct cds_lfht_node *old_node, | |
d6b18934 | 772 | struct cds_lfht_node *old_next, |
fa68aa62 MD |
773 | struct cds_lfht_node *new_node) |
774 | { | |
bec39940 | 775 | struct cds_lfht_node *bucket, *ret_next; |
fa68aa62 MD |
776 | |
777 | if (!old_node) /* Return -ENOENT if asked to replace NULL node */ | |
d6b18934 | 778 | return -ENOENT; |
fa68aa62 MD |
779 | |
780 | assert(!is_removed(old_node)); | |
bec39940 | 781 | assert(!is_bucket(old_node)); |
fa68aa62 | 782 | assert(!is_removed(new_node)); |
bec39940 | 783 | assert(!is_bucket(new_node)); |
fa68aa62 | 784 | assert(new_node != old_node); |
d6b18934 | 785 | for (;;) { |
fa68aa62 | 786 | /* Insert after node to be replaced */ |
fa68aa62 MD |
787 | if (is_removed(old_next)) { |
788 | /* | |
789 | * Too late, the old node has been removed under us | |
790 | * between lookup and replace. Fail. | |
791 | */ | |
d6b18934 | 792 | return -ENOENT; |
fa68aa62 | 793 | } |
bec39940 DG |
794 | assert(old_next == clear_flag(old_next)); |
795 | assert(new_node != old_next); | |
796 | new_node->next = old_next; | |
fa68aa62 MD |
797 | /* |
798 | * Here is the whole trick for lock-free replace: we add | |
799 | * the replacement node _after_ the node we want to | |
800 | * replace by atomically setting its next pointer at the | |
801 | * same time we set its removal flag. Given that | |
802 | * the lookups/get next use an iterator aware of the | |
803 | * next pointer, they will either skip the old node due | |
804 | * to the removal flag and see the new node, or use | |
805 | * the old node, but will not see the new one. | |
bec39940 DG |
806 | * This is a replacement of a node with another node |
807 | * that has the same value: we are therefore not | |
808 | * removing a value from the hash table. | |
fa68aa62 | 809 | */ |
bec39940 | 810 | ret_next = uatomic_cmpxchg(&old_node->next, |
fa68aa62 | 811 | old_next, flag_removed(new_node)); |
d6b18934 DG |
812 | if (ret_next == old_next) |
813 | break; /* We performed the replacement. */ | |
814 | old_next = ret_next; | |
815 | } | |
fa68aa62 MD |
816 | |
817 | /* | |
818 | * Ensure that the old node is not visible to readers anymore: | |
819 | * lookup for the node, and remove it (along with any other | |
820 | * logically removed node) if found. | |
821 | */ | |
bec39940 DG |
822 | bucket = lookup_bucket(ht, size, bit_reverse_ulong(old_node->reverse_hash)); |
823 | _cds_lfht_gc_bucket(bucket, new_node); | |
d6b18934 | 824 | |
bec39940 | 825 | assert(is_removed(rcu_dereference(old_node->next))); |
d6b18934 | 826 | return 0; |
fa68aa62 MD |
827 | } |
828 | ||
d6b18934 DG |
829 | /* |
830 | * A non-NULL unique_ret pointer uses the "add unique" (or uniquify) add | |
831 | * mode. A NULL unique_ret allows creation of duplicate keys. | |
832 | */ | |
fa68aa62 | 833 | static |
d6b18934 | 834 | void _cds_lfht_add(struct cds_lfht *ht, |
bec39940 DG |
835 | unsigned long hash, |
836 | cds_lfht_match_fct match, | |
837 | const void *key, | |
d6b18934 DG |
838 | unsigned long size, |
839 | struct cds_lfht_node *node, | |
840 | struct cds_lfht_iter *unique_ret, | |
bec39940 | 841 | int bucket_flag) |
fa68aa62 MD |
842 | { |
843 | struct cds_lfht_node *iter_prev, *iter, *next, *new_node, *new_next, | |
d6b18934 | 844 | *return_node; |
bec39940 | 845 | struct cds_lfht_node *bucket; |
fa68aa62 | 846 | |
bec39940 | 847 | assert(!is_bucket(node)); |
fa68aa62 | 848 | assert(!is_removed(node)); |
bec39940 | 849 | bucket = lookup_bucket(ht, size, hash); |
fa68aa62 MD |
850 | for (;;) { |
851 | uint32_t chain_len = 0; | |
852 | ||
853 | /* | |
854 | * iter_prev points to the non-removed node prior to the | |
855 | * insert location. | |
856 | */ | |
bec39940 DG |
857 | iter_prev = bucket; |
858 | /* We can always skip the bucket node initially */ | |
859 | iter = rcu_dereference(iter_prev->next); | |
860 | assert(iter_prev->reverse_hash <= node->reverse_hash); | |
fa68aa62 | 861 | for (;;) { |
6e59ae26 | 862 | if (caa_unlikely(is_end(iter))) |
fa68aa62 | 863 | goto insert; |
bec39940 | 864 | if (caa_likely(clear_flag(iter)->reverse_hash > node->reverse_hash)) |
fa68aa62 | 865 | goto insert; |
d6b18934 | 866 | |
bec39940 DG |
867 | /* bucket node is the first node of the identical-hash-value chain */ |
868 | if (bucket_flag && clear_flag(iter)->reverse_hash == node->reverse_hash) | |
d6b18934 DG |
869 | goto insert; |
870 | ||
bec39940 | 871 | next = rcu_dereference(clear_flag(iter)->next); |
6e59ae26 | 872 | if (caa_unlikely(is_removed(next))) |
fa68aa62 | 873 | goto gc_node; |
d6b18934 DG |
874 | |
875 | /* uniquely add */ | |
876 | if (unique_ret | |
bec39940 DG |
877 | && !is_bucket(next) |
878 | && clear_flag(iter)->reverse_hash == node->reverse_hash) { | |
d6b18934 DG |
879 | struct cds_lfht_iter d_iter = { .node = node, .next = iter, }; |
880 | ||
881 | /* | |
882 | * uniquely adding inserts the node as the first | |
883 | * node of the identical-hash-value node chain. | |
884 | * | |
885 | * This semantic ensures no duplicated keys | |
886 | * should ever be observable in the table | |
887 | * (including observe one node by one node | |
888 | * by forward iterations) | |
889 | */ | |
bec39940 | 890 | cds_lfht_next_duplicate(ht, match, key, &d_iter); |
d6b18934 DG |
891 | if (!d_iter.node) |
892 | goto insert; | |
893 | ||
894 | *unique_ret = d_iter; | |
895 | return; | |
fa68aa62 | 896 | } |
d6b18934 | 897 | |
fa68aa62 | 898 | /* Only account for identical reverse hash once */ |
bec39940 DG |
899 | if (iter_prev->reverse_hash != clear_flag(iter)->reverse_hash |
900 | && !is_bucket(next)) | |
fa68aa62 MD |
901 | check_resize(ht, size, ++chain_len); |
902 | iter_prev = clear_flag(iter); | |
903 | iter = next; | |
904 | } | |
905 | ||
906 | insert: | |
907 | assert(node != clear_flag(iter)); | |
908 | assert(!is_removed(iter_prev)); | |
909 | assert(!is_removed(iter)); | |
910 | assert(iter_prev != node); | |
bec39940 DG |
911 | if (!bucket_flag) |
912 | node->next = clear_flag(iter); | |
fa68aa62 | 913 | else |
bec39940 DG |
914 | node->next = flag_bucket(clear_flag(iter)); |
915 | if (is_bucket(iter)) | |
916 | new_node = flag_bucket(node); | |
fa68aa62 MD |
917 | else |
918 | new_node = node; | |
bec39940 | 919 | if (uatomic_cmpxchg(&iter_prev->next, iter, |
fa68aa62 MD |
920 | new_node) != iter) { |
921 | continue; /* retry */ | |
922 | } else { | |
d6b18934 DG |
923 | return_node = node; |
924 | goto end; | |
fa68aa62 MD |
925 | } |
926 | ||
927 | gc_node: | |
928 | assert(!is_removed(iter)); | |
bec39940 DG |
929 | if (is_bucket(iter)) |
930 | new_next = flag_bucket(clear_flag(next)); | |
fa68aa62 MD |
931 | else |
932 | new_next = clear_flag(next); | |
bec39940 | 933 | (void) uatomic_cmpxchg(&iter_prev->next, iter, new_next); |
fa68aa62 MD |
934 | /* retry */ |
935 | } | |
fa68aa62 | 936 | end: |
d6b18934 DG |
937 | if (unique_ret) { |
938 | unique_ret->node = return_node; | |
939 | /* unique_ret->next left unset, never used. */ | |
940 | } | |
fa68aa62 MD |
941 | } |
942 | ||
943 | static | |
944 | int _cds_lfht_del(struct cds_lfht *ht, unsigned long size, | |
bec39940 | 945 | struct cds_lfht_node *node) |
fa68aa62 | 946 | { |
bec39940 | 947 | struct cds_lfht_node *bucket, *next; |
fa68aa62 MD |
948 | |
949 | if (!node) /* Return -ENOENT if asked to delete NULL node */ | |
d6b18934 | 950 | return -ENOENT; |
fa68aa62 MD |
951 | |
952 | /* logically delete the node */ | |
bec39940 | 953 | assert(!is_bucket(node)); |
fa68aa62 | 954 | assert(!is_removed(node)); |
bec39940 | 955 | assert(!is_removal_owner(node)); |
fa68aa62 | 956 | |
bec39940 DG |
957 | /* |
958 | * We are first checking if the node had previously been | |
959 | * logically removed (this check is not atomic with setting the | |
960 | * logical removal flag). Return -ENOENT if the node had | |
961 | * previously been removed. | |
962 | */ | |
963 | next = rcu_dereference(node->next); | |
964 | if (caa_unlikely(is_removed(next))) | |
965 | return -ENOENT; | |
966 | assert(!is_bucket(next)); | |
967 | /* | |
968 | * We set the REMOVED_FLAG unconditionally. Note that there may | |
969 | * be more than one concurrent thread setting this flag. | |
970 | * Knowing which wins the race will be known after the garbage | |
971 | * collection phase, stay tuned! | |
972 | */ | |
973 | uatomic_or(&node->next, REMOVED_FLAG); | |
fa68aa62 | 974 | /* We performed the (logical) deletion. */ |
fa68aa62 MD |
975 | |
976 | /* | |
977 | * Ensure that the node is not visible to readers anymore: lookup for | |
978 | * the node, and remove it (along with any other logically removed node) | |
979 | * if found. | |
980 | */ | |
bec39940 DG |
981 | bucket = lookup_bucket(ht, size, bit_reverse_ulong(node->reverse_hash)); |
982 | _cds_lfht_gc_bucket(bucket, node); | |
d6b18934 | 983 | |
bec39940 DG |
984 | assert(is_removed(rcu_dereference(node->next))); |
985 | /* | |
986 | * Last phase: atomically exchange node->next with a version | |
987 | * having "REMOVAL_OWNER_FLAG" set. If the returned node->next | |
988 | * pointer did _not_ have "REMOVAL_OWNER_FLAG" set, we now own | |
989 | * the node and win the removal race. | |
990 | * It is interesting to note that all "add" paths are forbidden | |
991 | * to change the next pointer starting from the point where the | |
992 | * REMOVED_FLAG is set, so here using a read, followed by a | |
993 | * xchg() suffice to guarantee that the xchg() will ever only | |
994 | * set the "REMOVAL_OWNER_FLAG" (or change nothing if the flag | |
995 | * was already set). | |
996 | */ | |
997 | if (!is_removal_owner(uatomic_xchg(&node->next, | |
998 | flag_removal_owner(node->next)))) | |
999 | return 0; | |
1000 | else | |
1001 | return -ENOENT; | |
fa68aa62 MD |
1002 | } |
1003 | ||
1004 | static | |
1005 | void *partition_resize_thread(void *arg) | |
1006 | { | |
1007 | struct partition_resize_work *work = arg; | |
1008 | ||
bec39940 | 1009 | work->ht->flavor->register_thread(); |
fa68aa62 | 1010 | work->fct(work->ht, work->i, work->start, work->len); |
bec39940 | 1011 | work->ht->flavor->unregister_thread(); |
fa68aa62 MD |
1012 | return NULL; |
1013 | } | |
1014 | ||
1015 | static | |
1016 | void partition_resize_helper(struct cds_lfht *ht, unsigned long i, | |
1017 | unsigned long len, | |
1018 | void (*fct)(struct cds_lfht *ht, unsigned long i, | |
1019 | unsigned long start, unsigned long len)) | |
1020 | { | |
1021 | unsigned long partition_len; | |
1022 | struct partition_resize_work *work; | |
1023 | int thread, ret; | |
1024 | unsigned long nr_threads; | |
fa68aa62 MD |
1025 | |
1026 | /* | |
1027 | * Note: nr_cpus_mask + 1 is always power of 2. | |
1028 | * We spawn just the number of threads we need to satisfy the minimum | |
1029 | * partition size, up to the number of CPUs in the system. | |
1030 | */ | |
f6a9efaa DG |
1031 | if (nr_cpus_mask > 0) { |
1032 | nr_threads = min(nr_cpus_mask + 1, | |
1033 | len >> MIN_PARTITION_PER_THREAD_ORDER); | |
1034 | } else { | |
1035 | nr_threads = 1; | |
1036 | } | |
bec39940 | 1037 | partition_len = len >> cds_lfht_get_count_order_ulong(nr_threads); |
fa68aa62 | 1038 | work = calloc(nr_threads, sizeof(*work)); |
fa68aa62 | 1039 | assert(work); |
9ef70f87 | 1040 | pthread_mutex_lock(<tng_libc_state_lock); |
fa68aa62 MD |
1041 | for (thread = 0; thread < nr_threads; thread++) { |
1042 | work[thread].ht = ht; | |
1043 | work[thread].i = i; | |
1044 | work[thread].len = partition_len; | |
1045 | work[thread].start = thread * partition_len; | |
1046 | work[thread].fct = fct; | |
d6b18934 | 1047 | ret = pthread_create(&(work[thread].thread_id), ht->resize_attr, |
fa68aa62 MD |
1048 | partition_resize_thread, &work[thread]); |
1049 | assert(!ret); | |
1050 | } | |
1051 | for (thread = 0; thread < nr_threads; thread++) { | |
d6b18934 | 1052 | ret = pthread_join(work[thread].thread_id, NULL); |
fa68aa62 MD |
1053 | assert(!ret); |
1054 | } | |
9ef70f87 | 1055 | pthread_mutex_unlock(<tng_libc_state_lock); |
fa68aa62 | 1056 | free(work); |
fa68aa62 MD |
1057 | } |
1058 | ||
1059 | /* | |
1060 | * Holding RCU read lock to protect _cds_lfht_add against memory | |
1061 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
1062 | * problem). | |
1063 | * | |
1064 | * When we reach a certain length, we can split this population phase over | |
1065 | * many worker threads, based on the number of CPUs available in the system. | |
1066 | * This should therefore take care of not having the expand lagging behind too | |
1067 | * many concurrent insertion threads by using the scheduler's ability to | |
bec39940 | 1068 | * schedule bucket node population fairly with insertions. |
fa68aa62 MD |
1069 | */ |
1070 | static | |
1071 | void init_table_populate_partition(struct cds_lfht *ht, unsigned long i, | |
1072 | unsigned long start, unsigned long len) | |
1073 | { | |
bec39940 | 1074 | unsigned long j, size = 1UL << (i - 1); |
fa68aa62 | 1075 | |
bec39940 DG |
1076 | assert(i > MIN_TABLE_ORDER); |
1077 | ht->flavor->read_lock(); | |
1078 | for (j = size + start; j < size + start + len; j++) { | |
1079 | struct cds_lfht_node *new_node = bucket_at(ht, j); | |
fa68aa62 | 1080 | |
bec39940 DG |
1081 | assert(j >= size && j < (size << 1)); |
1082 | dbg_printf("init populate: order %lu index %lu hash %lu\n", | |
1083 | i, j, j); | |
1084 | new_node->reverse_hash = bit_reverse_ulong(j); | |
1085 | _cds_lfht_add(ht, j, NULL, NULL, size, new_node, NULL, 1); | |
fa68aa62 | 1086 | } |
bec39940 | 1087 | ht->flavor->read_unlock(); |
fa68aa62 MD |
1088 | } |
1089 | ||
1090 | static | |
1091 | void init_table_populate(struct cds_lfht *ht, unsigned long i, | |
1092 | unsigned long len) | |
1093 | { | |
1094 | assert(nr_cpus_mask != -1); | |
1095 | if (nr_cpus_mask < 0 || len < 2 * MIN_PARTITION_PER_THREAD) { | |
bec39940 | 1096 | ht->flavor->thread_online(); |
fa68aa62 | 1097 | init_table_populate_partition(ht, i, 0, len); |
bec39940 | 1098 | ht->flavor->thread_offline(); |
fa68aa62 MD |
1099 | return; |
1100 | } | |
1101 | partition_resize_helper(ht, i, len, init_table_populate_partition); | |
1102 | } | |
1103 | ||
1104 | static | |
1105 | void init_table(struct cds_lfht *ht, | |
d6b18934 | 1106 | unsigned long first_order, unsigned long last_order) |
fa68aa62 | 1107 | { |
d6b18934 | 1108 | unsigned long i; |
fa68aa62 | 1109 | |
d6b18934 DG |
1110 | dbg_printf("init table: first_order %lu last_order %lu\n", |
1111 | first_order, last_order); | |
bec39940 | 1112 | assert(first_order > MIN_TABLE_ORDER); |
d6b18934 | 1113 | for (i = first_order; i <= last_order; i++) { |
fa68aa62 MD |
1114 | unsigned long len; |
1115 | ||
d6b18934 | 1116 | len = 1UL << (i - 1); |
fa68aa62 MD |
1117 | dbg_printf("init order %lu len: %lu\n", i, len); |
1118 | ||
1119 | /* Stop expand if the resize target changes under us */ | |
bec39940 | 1120 | if (CMM_LOAD_SHARED(ht->resize_target) < (1UL << i)) |
fa68aa62 MD |
1121 | break; |
1122 | ||
bec39940 | 1123 | cds_lfht_alloc_bucket_table(ht, i); |
fa68aa62 MD |
1124 | |
1125 | /* | |
bec39940 DG |
1126 | * Set all bucket nodes reverse hash values for a level and |
1127 | * link all bucket nodes into the table. | |
fa68aa62 MD |
1128 | */ |
1129 | init_table_populate(ht, i, len); | |
1130 | ||
1131 | /* | |
1132 | * Update table size. | |
1133 | */ | |
1134 | cmm_smp_wmb(); /* populate data before RCU size */ | |
bec39940 | 1135 | CMM_STORE_SHARED(ht->size, 1UL << i); |
fa68aa62 | 1136 | |
d6b18934 | 1137 | dbg_printf("init new size: %lu\n", 1UL << i); |
fa68aa62 MD |
1138 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) |
1139 | break; | |
1140 | } | |
1141 | } | |
1142 | ||
1143 | /* | |
1144 | * Holding RCU read lock to protect _cds_lfht_remove against memory | |
1145 | * reclaim that could be performed by other call_rcu worker threads (ABA | |
1146 | * problem). | |
1147 | * For a single level, we logically remove and garbage collect each node. | |
1148 | * | |
1149 | * As a design choice, we perform logical removal and garbage collection on a | |
1150 | * node-per-node basis to simplify this algorithm. We also assume keeping good | |
1151 | * cache locality of the operation would overweight possible performance gain | |
1152 | * that could be achieved by batching garbage collection for multiple levels. | |
1153 | * However, this would have to be justified by benchmarks. | |
1154 | * | |
1155 | * Concurrent removal and add operations are helping us perform garbage | |
1156 | * collection of logically removed nodes. We guarantee that all logically | |
1157 | * removed nodes have been garbage-collected (unlinked) before call_rcu is | |
bec39940 | 1158 | * invoked to free a hole level of bucket nodes (after a grace period). |
fa68aa62 MD |
1159 | * |
1160 | * Logical removal and garbage collection can therefore be done in batch or on a | |
1161 | * node-per-node basis, as long as the guarantee above holds. | |
1162 | * | |
1163 | * When we reach a certain length, we can split this removal over many worker | |
1164 | * threads, based on the number of CPUs available in the system. This should | |
1165 | * take care of not letting resize process lag behind too many concurrent | |
1166 | * updater threads actively inserting into the hash table. | |
1167 | */ | |
1168 | static | |
1169 | void remove_table_partition(struct cds_lfht *ht, unsigned long i, | |
1170 | unsigned long start, unsigned long len) | |
1171 | { | |
bec39940 | 1172 | unsigned long j, size = 1UL << (i - 1); |
fa68aa62 | 1173 | |
bec39940 DG |
1174 | assert(i > MIN_TABLE_ORDER); |
1175 | ht->flavor->read_lock(); | |
1176 | for (j = size + start; j < size + start + len; j++) { | |
1177 | struct cds_lfht_node *fini_bucket = bucket_at(ht, j); | |
1178 | struct cds_lfht_node *parent_bucket = bucket_at(ht, j - size); | |
fa68aa62 | 1179 | |
bec39940 DG |
1180 | assert(j >= size && j < (size << 1)); |
1181 | dbg_printf("remove entry: order %lu index %lu hash %lu\n", | |
1182 | i, j, j); | |
1183 | /* Set the REMOVED_FLAG to freeze the ->next for gc */ | |
1184 | uatomic_or(&fini_bucket->next, REMOVED_FLAG); | |
1185 | _cds_lfht_gc_bucket(parent_bucket, fini_bucket); | |
fa68aa62 | 1186 | } |
bec39940 | 1187 | ht->flavor->read_unlock(); |
fa68aa62 MD |
1188 | } |
1189 | ||
1190 | static | |
1191 | void remove_table(struct cds_lfht *ht, unsigned long i, unsigned long len) | |
1192 | { | |
1193 | ||
1194 | assert(nr_cpus_mask != -1); | |
1195 | if (nr_cpus_mask < 0 || len < 2 * MIN_PARTITION_PER_THREAD) { | |
bec39940 | 1196 | ht->flavor->thread_online(); |
fa68aa62 | 1197 | remove_table_partition(ht, i, 0, len); |
bec39940 | 1198 | ht->flavor->thread_offline(); |
fa68aa62 MD |
1199 | return; |
1200 | } | |
1201 | partition_resize_helper(ht, i, len, remove_table_partition); | |
1202 | } | |
1203 | ||
bec39940 DG |
1204 | /* |
1205 | * fini_table() is never called for first_order == 0, which is why | |
1206 | * free_by_rcu_order == 0 can be used as criterion to know if free must | |
1207 | * be called. | |
1208 | */ | |
fa68aa62 MD |
1209 | static |
1210 | void fini_table(struct cds_lfht *ht, | |
d6b18934 | 1211 | unsigned long first_order, unsigned long last_order) |
fa68aa62 | 1212 | { |
d6b18934 | 1213 | long i; |
bec39940 | 1214 | unsigned long free_by_rcu_order = 0; |
fa68aa62 | 1215 | |
d6b18934 DG |
1216 | dbg_printf("fini table: first_order %lu last_order %lu\n", |
1217 | first_order, last_order); | |
bec39940 | 1218 | assert(first_order > MIN_TABLE_ORDER); |
d6b18934 | 1219 | for (i = last_order; i >= first_order; i--) { |
fa68aa62 MD |
1220 | unsigned long len; |
1221 | ||
d6b18934 | 1222 | len = 1UL << (i - 1); |
fa68aa62 MD |
1223 | dbg_printf("fini order %lu len: %lu\n", i, len); |
1224 | ||
1225 | /* Stop shrink if the resize target changes under us */ | |
bec39940 | 1226 | if (CMM_LOAD_SHARED(ht->resize_target) > (1UL << (i - 1))) |
fa68aa62 MD |
1227 | break; |
1228 | ||
1229 | cmm_smp_wmb(); /* populate data before RCU size */ | |
bec39940 | 1230 | CMM_STORE_SHARED(ht->size, 1UL << (i - 1)); |
fa68aa62 MD |
1231 | |
1232 | /* | |
1233 | * We need to wait for all add operations to reach Q.S. (and | |
1234 | * thus use the new table for lookups) before we can start | |
bec39940 | 1235 | * releasing the old bucket nodes. Otherwise their lookup will |
fa68aa62 MD |
1236 | * return a logically removed node as insert position. |
1237 | */ | |
bec39940 DG |
1238 | ht->flavor->update_synchronize_rcu(); |
1239 | if (free_by_rcu_order) | |
1240 | cds_lfht_free_bucket_table(ht, free_by_rcu_order); | |
fa68aa62 MD |
1241 | |
1242 | /* | |
bec39940 DG |
1243 | * Set "removed" flag in bucket nodes about to be removed. |
1244 | * Unlink all now-logically-removed bucket node pointers. | |
fa68aa62 MD |
1245 | * Concurrent add/remove operation are helping us doing |
1246 | * the gc. | |
1247 | */ | |
1248 | remove_table(ht, i, len); | |
1249 | ||
bec39940 | 1250 | free_by_rcu_order = i; |
fa68aa62 MD |
1251 | |
1252 | dbg_printf("fini new size: %lu\n", 1UL << i); | |
1253 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
1254 | break; | |
1255 | } | |
d6b18934 | 1256 | |
bec39940 DG |
1257 | if (free_by_rcu_order) { |
1258 | ht->flavor->update_synchronize_rcu(); | |
1259 | cds_lfht_free_bucket_table(ht, free_by_rcu_order); | |
d6b18934 DG |
1260 | } |
1261 | } | |
1262 | ||
1263 | static | |
bec39940 | 1264 | void cds_lfht_create_bucket(struct cds_lfht *ht, unsigned long size) |
d6b18934 | 1265 | { |
bec39940 DG |
1266 | struct cds_lfht_node *prev, *node; |
1267 | unsigned long order, len, i; | |
d6b18934 | 1268 | |
bec39940 | 1269 | cds_lfht_alloc_bucket_table(ht, 0); |
d6b18934 | 1270 | |
bec39940 DG |
1271 | dbg_printf("create bucket: order 0 index 0 hash 0\n"); |
1272 | node = bucket_at(ht, 0); | |
1273 | node->next = flag_bucket(get_end()); | |
1274 | node->reverse_hash = 0; | |
d6b18934 | 1275 | |
bec39940 | 1276 | for (order = 1; order < cds_lfht_get_count_order_ulong(size) + 1; order++) { |
d6b18934 | 1277 | len = 1UL << (order - 1); |
bec39940 | 1278 | cds_lfht_alloc_bucket_table(ht, order); |
d6b18934 | 1279 | |
bec39940 DG |
1280 | for (i = 0; i < len; i++) { |
1281 | /* | |
1282 | * Now, we are trying to init the node with the | |
1283 | * hash=(len+i) (which is also a bucket with the | |
1284 | * index=(len+i)) and insert it into the hash table, | |
1285 | * so this node has to be inserted after the bucket | |
1286 | * with the index=(len+i)&(len-1)=i. And because there | |
1287 | * is no other non-bucket node nor bucket node with | |
1288 | * larger index/hash inserted, so the bucket node | |
1289 | * being inserted should be inserted directly linked | |
1290 | * after the bucket node with index=i. | |
1291 | */ | |
1292 | prev = bucket_at(ht, i); | |
1293 | node = bucket_at(ht, len + i); | |
1294 | ||
1295 | dbg_printf("create bucket: order %lu index %lu hash %lu\n", | |
1296 | order, len + i, len + i); | |
1297 | node->reverse_hash = bit_reverse_ulong(len + i); | |
d6b18934 | 1298 | |
bec39940 DG |
1299 | /* insert after prev */ |
1300 | assert(is_bucket(prev->next)); | |
d6b18934 | 1301 | node->next = prev->next; |
bec39940 | 1302 | prev->next = flag_bucket(node); |
d6b18934 DG |
1303 | } |
1304 | } | |
fa68aa62 MD |
1305 | } |
1306 | ||
bec39940 DG |
1307 | struct cds_lfht *_cds_lfht_new(unsigned long init_size, |
1308 | unsigned long min_nr_alloc_buckets, | |
1309 | unsigned long max_nr_buckets, | |
fa68aa62 | 1310 | int flags, |
bec39940 DG |
1311 | const struct cds_lfht_mm_type *mm, |
1312 | const struct rcu_flavor_struct *flavor, | |
fa68aa62 MD |
1313 | pthread_attr_t *attr) |
1314 | { | |
1315 | struct cds_lfht *ht; | |
1316 | unsigned long order; | |
1317 | ||
bec39940 DG |
1318 | /* min_nr_alloc_buckets must be power of two */ |
1319 | if (!min_nr_alloc_buckets || (min_nr_alloc_buckets & (min_nr_alloc_buckets - 1))) | |
d6b18934 | 1320 | return NULL; |
bec39940 | 1321 | |
fa68aa62 | 1322 | /* init_size must be power of two */ |
d6b18934 | 1323 | if (!init_size || (init_size & (init_size - 1))) |
fa68aa62 | 1324 | return NULL; |
bec39940 DG |
1325 | |
1326 | /* | |
1327 | * Memory management plugin default. | |
1328 | */ | |
1329 | if (!mm) { | |
1330 | if (CAA_BITS_PER_LONG > 32 | |
1331 | && max_nr_buckets | |
1332 | && max_nr_buckets <= (1ULL << 32)) { | |
1333 | /* | |
1334 | * For 64-bit architectures, with max number of | |
1335 | * buckets small enough not to use the entire | |
1336 | * 64-bit memory mapping space (and allowing a | |
1337 | * fair number of hash table instances), use the | |
1338 | * mmap allocator, which is faster than the | |
1339 | * order allocator. | |
1340 | */ | |
1341 | mm = &cds_lfht_mm_mmap; | |
1342 | } else { | |
1343 | /* | |
1344 | * The fallback is to use the order allocator. | |
1345 | */ | |
1346 | mm = &cds_lfht_mm_order; | |
1347 | } | |
1348 | } | |
1349 | ||
1350 | /* max_nr_buckets == 0 for order based mm means infinite */ | |
1351 | if (mm == &cds_lfht_mm_order && !max_nr_buckets) | |
1352 | max_nr_buckets = 1UL << (MAX_TABLE_ORDER - 1); | |
1353 | ||
1354 | /* max_nr_buckets must be power of two */ | |
1355 | if (!max_nr_buckets || (max_nr_buckets & (max_nr_buckets - 1))) | |
1356 | return NULL; | |
1357 | ||
1358 | min_nr_alloc_buckets = max(min_nr_alloc_buckets, MIN_TABLE_SIZE); | |
1359 | init_size = max(init_size, MIN_TABLE_SIZE); | |
1360 | max_nr_buckets = max(max_nr_buckets, min_nr_alloc_buckets); | |
1361 | init_size = min(init_size, max_nr_buckets); | |
1362 | ||
1363 | ht = mm->alloc_cds_lfht(min_nr_alloc_buckets, max_nr_buckets); | |
fa68aa62 | 1364 | assert(ht); |
bec39940 DG |
1365 | assert(ht->mm == mm); |
1366 | assert(ht->bucket_at == mm->bucket_at); | |
1367 | ||
d6b18934 | 1368 | ht->flags = flags; |
bec39940 | 1369 | ht->flavor = flavor; |
fa68aa62 | 1370 | ht->resize_attr = attr; |
d6b18934 | 1371 | alloc_split_items_count(ht); |
fa68aa62 MD |
1372 | /* this mutex should not nest in read-side C.S. */ |
1373 | pthread_mutex_init(&ht->resize_mutex, NULL); | |
bec39940 DG |
1374 | order = cds_lfht_get_count_order_ulong(init_size); |
1375 | ht->resize_target = 1UL << order; | |
1376 | cds_lfht_create_bucket(ht, 1UL << order); | |
1377 | ht->size = 1UL << order; | |
fa68aa62 MD |
1378 | return ht; |
1379 | } | |
1380 | ||
bec39940 DG |
1381 | void cds_lfht_lookup(struct cds_lfht *ht, unsigned long hash, |
1382 | cds_lfht_match_fct match, const void *key, | |
fa68aa62 MD |
1383 | struct cds_lfht_iter *iter) |
1384 | { | |
bec39940 DG |
1385 | struct cds_lfht_node *node, *next, *bucket; |
1386 | unsigned long reverse_hash, size; | |
fa68aa62 | 1387 | |
fa68aa62 MD |
1388 | reverse_hash = bit_reverse_ulong(hash); |
1389 | ||
bec39940 DG |
1390 | size = rcu_dereference(ht->size); |
1391 | bucket = lookup_bucket(ht, size, hash); | |
1392 | /* We can always skip the bucket node initially */ | |
1393 | node = rcu_dereference(bucket->next); | |
fa68aa62 MD |
1394 | node = clear_flag(node); |
1395 | for (;;) { | |
6e59ae26 | 1396 | if (caa_unlikely(is_end(node))) { |
fa68aa62 MD |
1397 | node = next = NULL; |
1398 | break; | |
1399 | } | |
bec39940 | 1400 | if (caa_unlikely(node->reverse_hash > reverse_hash)) { |
fa68aa62 MD |
1401 | node = next = NULL; |
1402 | break; | |
1403 | } | |
bec39940 | 1404 | next = rcu_dereference(node->next); |
d6b18934 | 1405 | assert(node == clear_flag(node)); |
6e59ae26 | 1406 | if (caa_likely(!is_removed(next)) |
bec39940 DG |
1407 | && !is_bucket(next) |
1408 | && node->reverse_hash == reverse_hash | |
1409 | && caa_likely(match(node, key))) { | |
fa68aa62 MD |
1410 | break; |
1411 | } | |
1412 | node = clear_flag(next); | |
1413 | } | |
bec39940 | 1414 | assert(!node || !is_bucket(rcu_dereference(node->next))); |
fa68aa62 MD |
1415 | iter->node = node; |
1416 | iter->next = next; | |
1417 | } | |
1418 | ||
bec39940 DG |
1419 | void cds_lfht_next_duplicate(struct cds_lfht *ht, cds_lfht_match_fct match, |
1420 | const void *key, struct cds_lfht_iter *iter) | |
fa68aa62 MD |
1421 | { |
1422 | struct cds_lfht_node *node, *next; | |
1423 | unsigned long reverse_hash; | |
fa68aa62 MD |
1424 | |
1425 | node = iter->node; | |
bec39940 | 1426 | reverse_hash = node->reverse_hash; |
fa68aa62 MD |
1427 | next = iter->next; |
1428 | node = clear_flag(next); | |
1429 | ||
1430 | for (;;) { | |
6e59ae26 | 1431 | if (caa_unlikely(is_end(node))) { |
fa68aa62 MD |
1432 | node = next = NULL; |
1433 | break; | |
1434 | } | |
bec39940 | 1435 | if (caa_unlikely(node->reverse_hash > reverse_hash)) { |
fa68aa62 MD |
1436 | node = next = NULL; |
1437 | break; | |
1438 | } | |
bec39940 | 1439 | next = rcu_dereference(node->next); |
6e59ae26 | 1440 | if (caa_likely(!is_removed(next)) |
bec39940 DG |
1441 | && !is_bucket(next) |
1442 | && caa_likely(match(node, key))) { | |
fa68aa62 MD |
1443 | break; |
1444 | } | |
1445 | node = clear_flag(next); | |
1446 | } | |
bec39940 | 1447 | assert(!node || !is_bucket(rcu_dereference(node->next))); |
fa68aa62 MD |
1448 | iter->node = node; |
1449 | iter->next = next; | |
1450 | } | |
1451 | ||
f6a9efaa DG |
1452 | void cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_iter *iter) |
1453 | { | |
1454 | struct cds_lfht_node *node, *next; | |
1455 | ||
1456 | node = clear_flag(iter->next); | |
1457 | for (;;) { | |
6e59ae26 | 1458 | if (caa_unlikely(is_end(node))) { |
f6a9efaa DG |
1459 | node = next = NULL; |
1460 | break; | |
1461 | } | |
bec39940 | 1462 | next = rcu_dereference(node->next); |
6e59ae26 | 1463 | if (caa_likely(!is_removed(next)) |
bec39940 | 1464 | && !is_bucket(next)) { |
f6a9efaa DG |
1465 | break; |
1466 | } | |
1467 | node = clear_flag(next); | |
1468 | } | |
bec39940 | 1469 | assert(!node || !is_bucket(rcu_dereference(node->next))); |
f6a9efaa DG |
1470 | iter->node = node; |
1471 | iter->next = next; | |
1472 | } | |
1473 | ||
1474 | void cds_lfht_first(struct cds_lfht *ht, struct cds_lfht_iter *iter) | |
1475 | { | |
f6a9efaa | 1476 | /* |
bec39940 | 1477 | * Get next after first bucket node. The first bucket node is the |
f6a9efaa DG |
1478 | * first node of the linked list. |
1479 | */ | |
bec39940 | 1480 | iter->next = bucket_at(ht, 0)->next; |
f6a9efaa DG |
1481 | cds_lfht_next(ht, iter); |
1482 | } | |
1483 | ||
bec39940 DG |
1484 | void cds_lfht_add(struct cds_lfht *ht, unsigned long hash, |
1485 | struct cds_lfht_node *node) | |
fa68aa62 | 1486 | { |
bec39940 | 1487 | unsigned long size; |
fa68aa62 | 1488 | |
bec39940 DG |
1489 | node->reverse_hash = bit_reverse_ulong(hash); |
1490 | size = rcu_dereference(ht->size); | |
1491 | _cds_lfht_add(ht, hash, NULL, NULL, size, node, NULL, 0); | |
d6b18934 | 1492 | ht_count_add(ht, size, hash); |
fa68aa62 MD |
1493 | } |
1494 | ||
1495 | struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, | |
bec39940 DG |
1496 | unsigned long hash, |
1497 | cds_lfht_match_fct match, | |
1498 | const void *key, | |
fa68aa62 MD |
1499 | struct cds_lfht_node *node) |
1500 | { | |
bec39940 | 1501 | unsigned long size; |
d6b18934 | 1502 | struct cds_lfht_iter iter; |
fa68aa62 | 1503 | |
bec39940 DG |
1504 | node->reverse_hash = bit_reverse_ulong(hash); |
1505 | size = rcu_dereference(ht->size); | |
1506 | _cds_lfht_add(ht, hash, match, key, size, node, &iter, 0); | |
d6b18934 DG |
1507 | if (iter.node == node) |
1508 | ht_count_add(ht, size, hash); | |
1509 | return iter.node; | |
fa68aa62 MD |
1510 | } |
1511 | ||
1512 | struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht, | |
bec39940 DG |
1513 | unsigned long hash, |
1514 | cds_lfht_match_fct match, | |
1515 | const void *key, | |
fa68aa62 MD |
1516 | struct cds_lfht_node *node) |
1517 | { | |
bec39940 | 1518 | unsigned long size; |
d6b18934 | 1519 | struct cds_lfht_iter iter; |
fa68aa62 | 1520 | |
bec39940 DG |
1521 | node->reverse_hash = bit_reverse_ulong(hash); |
1522 | size = rcu_dereference(ht->size); | |
d6b18934 | 1523 | for (;;) { |
bec39940 | 1524 | _cds_lfht_add(ht, hash, match, key, size, node, &iter, 0); |
d6b18934 DG |
1525 | if (iter.node == node) { |
1526 | ht_count_add(ht, size, hash); | |
1527 | return NULL; | |
1528 | } | |
1529 | ||
1530 | if (!_cds_lfht_replace(ht, size, iter.node, iter.next, node)) | |
1531 | return iter.node; | |
1532 | } | |
fa68aa62 MD |
1533 | } |
1534 | ||
bec39940 DG |
1535 | int cds_lfht_replace(struct cds_lfht *ht, |
1536 | struct cds_lfht_iter *old_iter, | |
1537 | unsigned long hash, | |
1538 | cds_lfht_match_fct match, | |
1539 | const void *key, | |
fa68aa62 MD |
1540 | struct cds_lfht_node *new_node) |
1541 | { | |
1542 | unsigned long size; | |
1543 | ||
bec39940 DG |
1544 | new_node->reverse_hash = bit_reverse_ulong(hash); |
1545 | if (!old_iter->node) | |
1546 | return -ENOENT; | |
1547 | if (caa_unlikely(old_iter->node->reverse_hash != new_node->reverse_hash)) | |
1548 | return -EINVAL; | |
1549 | if (caa_unlikely(!match(old_iter->node, key))) | |
1550 | return -EINVAL; | |
1551 | size = rcu_dereference(ht->size); | |
fa68aa62 MD |
1552 | return _cds_lfht_replace(ht, size, old_iter->node, old_iter->next, |
1553 | new_node); | |
1554 | } | |
1555 | ||
bec39940 | 1556 | int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_node *node) |
fa68aa62 | 1557 | { |
d6b18934 | 1558 | unsigned long size, hash; |
fa68aa62 MD |
1559 | int ret; |
1560 | ||
bec39940 DG |
1561 | size = rcu_dereference(ht->size); |
1562 | ret = _cds_lfht_del(ht, size, node); | |
d6b18934 | 1563 | if (!ret) { |
bec39940 | 1564 | hash = bit_reverse_ulong(node->reverse_hash); |
d6b18934 DG |
1565 | ht_count_del(ht, size, hash); |
1566 | } | |
fa68aa62 MD |
1567 | return ret; |
1568 | } | |
1569 | ||
1570 | static | |
bec39940 | 1571 | int cds_lfht_delete_bucket(struct cds_lfht *ht) |
fa68aa62 MD |
1572 | { |
1573 | struct cds_lfht_node *node; | |
fa68aa62 MD |
1574 | unsigned long order, i, size; |
1575 | ||
1576 | /* Check that the table is empty */ | |
bec39940 | 1577 | node = bucket_at(ht, 0); |
fa68aa62 | 1578 | do { |
bec39940 DG |
1579 | node = clear_flag(node)->next; |
1580 | if (!is_bucket(node)) | |
fa68aa62 MD |
1581 | return -EPERM; |
1582 | assert(!is_removed(node)); | |
1583 | } while (!is_end(node)); | |
1584 | /* | |
1585 | * size accessed without rcu_dereference because hash table is | |
1586 | * being destroyed. | |
1587 | */ | |
bec39940 DG |
1588 | size = ht->size; |
1589 | /* Internal sanity check: all nodes left should be bucket */ | |
1590 | for (i = 0; i < size; i++) { | |
1591 | node = bucket_at(ht, i); | |
1592 | dbg_printf("delete bucket: index %lu expected hash %lu hash %lu\n", | |
1593 | i, i, bit_reverse_ulong(node->reverse_hash)); | |
1594 | assert(is_bucket(node->next)); | |
1595 | } | |
fa68aa62 | 1596 | |
bec39940 DG |
1597 | for (order = cds_lfht_get_count_order_ulong(size); (long)order >= 0; order--) |
1598 | cds_lfht_free_bucket_table(ht, order); | |
d6b18934 | 1599 | |
fa68aa62 MD |
1600 | return 0; |
1601 | } | |
1602 | ||
1603 | /* | |
1604 | * Should only be called when no more concurrent readers nor writers can | |
1605 | * possibly access the table. | |
1606 | */ | |
1607 | int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr) | |
1608 | { | |
1609 | int ret; | |
1610 | ||
1611 | /* Wait for in-flight resize operations to complete */ | |
d6b18934 DG |
1612 | _CMM_STORE_SHARED(ht->in_progress_destroy, 1); |
1613 | cmm_smp_mb(); /* Store destroy before load resize */ | |
fa68aa62 MD |
1614 | while (uatomic_read(&ht->in_progress_resize)) |
1615 | poll(NULL, 0, 100); /* wait for 100ms */ | |
bec39940 | 1616 | ret = cds_lfht_delete_bucket(ht); |
fa68aa62 MD |
1617 | if (ret) |
1618 | return ret; | |
d6b18934 | 1619 | free_split_items_count(ht); |
fa68aa62 MD |
1620 | if (attr) |
1621 | *attr = ht->resize_attr; | |
1622 | poison_free(ht); | |
1623 | return ret; | |
1624 | } | |
1625 | ||
1626 | void cds_lfht_count_nodes(struct cds_lfht *ht, | |
1627 | long *approx_before, | |
1628 | unsigned long *count, | |
fa68aa62 MD |
1629 | long *approx_after) |
1630 | { | |
1631 | struct cds_lfht_node *node, *next; | |
bec39940 | 1632 | unsigned long nr_bucket = 0, nr_removed = 0; |
fa68aa62 MD |
1633 | |
1634 | *approx_before = 0; | |
d6b18934 | 1635 | if (ht->split_count) { |
fa68aa62 MD |
1636 | int i; |
1637 | ||
d6b18934 DG |
1638 | for (i = 0; i < split_count_mask + 1; i++) { |
1639 | *approx_before += uatomic_read(&ht->split_count[i].add); | |
1640 | *approx_before -= uatomic_read(&ht->split_count[i].del); | |
fa68aa62 MD |
1641 | } |
1642 | } | |
1643 | ||
1644 | *count = 0; | |
fa68aa62 | 1645 | |
bec39940 DG |
1646 | /* Count non-bucket nodes in the table */ |
1647 | node = bucket_at(ht, 0); | |
fa68aa62 | 1648 | do { |
bec39940 | 1649 | next = rcu_dereference(node->next); |
fa68aa62 | 1650 | if (is_removed(next)) { |
bec39940 DG |
1651 | if (!is_bucket(next)) |
1652 | (nr_removed)++; | |
fa68aa62 | 1653 | else |
bec39940 DG |
1654 | (nr_bucket)++; |
1655 | } else if (!is_bucket(next)) | |
fa68aa62 MD |
1656 | (*count)++; |
1657 | else | |
bec39940 | 1658 | (nr_bucket)++; |
fa68aa62 MD |
1659 | node = clear_flag(next); |
1660 | } while (!is_end(node)); | |
bec39940 DG |
1661 | dbg_printf("number of logically removed nodes: %lu\n", nr_removed); |
1662 | dbg_printf("number of bucket nodes: %lu\n", nr_bucket); | |
fa68aa62 | 1663 | *approx_after = 0; |
d6b18934 | 1664 | if (ht->split_count) { |
fa68aa62 MD |
1665 | int i; |
1666 | ||
d6b18934 DG |
1667 | for (i = 0; i < split_count_mask + 1; i++) { |
1668 | *approx_after += uatomic_read(&ht->split_count[i].add); | |
1669 | *approx_after -= uatomic_read(&ht->split_count[i].del); | |
fa68aa62 MD |
1670 | } |
1671 | } | |
1672 | } | |
1673 | ||
1674 | /* called with resize mutex held */ | |
1675 | static | |
1676 | void _do_cds_lfht_grow(struct cds_lfht *ht, | |
1677 | unsigned long old_size, unsigned long new_size) | |
1678 | { | |
1679 | unsigned long old_order, new_order; | |
1680 | ||
bec39940 DG |
1681 | old_order = cds_lfht_get_count_order_ulong(old_size); |
1682 | new_order = cds_lfht_get_count_order_ulong(new_size); | |
d6b18934 DG |
1683 | dbg_printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", |
1684 | old_size, old_order, new_size, new_order); | |
fa68aa62 | 1685 | assert(new_size > old_size); |
d6b18934 | 1686 | init_table(ht, old_order + 1, new_order); |
fa68aa62 MD |
1687 | } |
1688 | ||
1689 | /* called with resize mutex held */ | |
1690 | static | |
1691 | void _do_cds_lfht_shrink(struct cds_lfht *ht, | |
1692 | unsigned long old_size, unsigned long new_size) | |
1693 | { | |
1694 | unsigned long old_order, new_order; | |
1695 | ||
bec39940 DG |
1696 | new_size = max(new_size, MIN_TABLE_SIZE); |
1697 | old_order = cds_lfht_get_count_order_ulong(old_size); | |
1698 | new_order = cds_lfht_get_count_order_ulong(new_size); | |
d6b18934 DG |
1699 | dbg_printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n", |
1700 | old_size, old_order, new_size, new_order); | |
fa68aa62 MD |
1701 | assert(new_size < old_size); |
1702 | ||
bec39940 | 1703 | /* Remove and unlink all bucket nodes to remove. */ |
d6b18934 | 1704 | fini_table(ht, new_order + 1, old_order); |
fa68aa62 MD |
1705 | } |
1706 | ||
1707 | ||
1708 | /* called with resize mutex held */ | |
1709 | static | |
1710 | void _do_cds_lfht_resize(struct cds_lfht *ht) | |
1711 | { | |
1712 | unsigned long new_size, old_size; | |
1713 | ||
1714 | /* | |
1715 | * Resize table, re-do if the target size has changed under us. | |
1716 | */ | |
1717 | do { | |
d6b18934 DG |
1718 | assert(uatomic_read(&ht->in_progress_resize)); |
1719 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) | |
1720 | break; | |
bec39940 DG |
1721 | ht->resize_initiated = 1; |
1722 | old_size = ht->size; | |
1723 | new_size = CMM_LOAD_SHARED(ht->resize_target); | |
fa68aa62 MD |
1724 | if (old_size < new_size) |
1725 | _do_cds_lfht_grow(ht, old_size, new_size); | |
1726 | else if (old_size > new_size) | |
1727 | _do_cds_lfht_shrink(ht, old_size, new_size); | |
bec39940 | 1728 | ht->resize_initiated = 0; |
fa68aa62 MD |
1729 | /* write resize_initiated before read resize_target */ |
1730 | cmm_smp_mb(); | |
bec39940 | 1731 | } while (ht->size != CMM_LOAD_SHARED(ht->resize_target)); |
fa68aa62 MD |
1732 | } |
1733 | ||
1734 | static | |
bec39940 | 1735 | unsigned long resize_target_grow(struct cds_lfht *ht, unsigned long new_size) |
fa68aa62 | 1736 | { |
bec39940 | 1737 | return _uatomic_xchg_monotonic_increase(&ht->resize_target, new_size); |
fa68aa62 MD |
1738 | } |
1739 | ||
1740 | static | |
1741 | void resize_target_update_count(struct cds_lfht *ht, | |
1742 | unsigned long count) | |
1743 | { | |
bec39940 DG |
1744 | count = max(count, MIN_TABLE_SIZE); |
1745 | count = min(count, ht->max_nr_buckets); | |
1746 | uatomic_set(&ht->resize_target, count); | |
fa68aa62 MD |
1747 | } |
1748 | ||
1749 | void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size) | |
1750 | { | |
1751 | resize_target_update_count(ht, new_size); | |
bec39940 DG |
1752 | CMM_STORE_SHARED(ht->resize_initiated, 1); |
1753 | ht->flavor->thread_offline(); | |
fa68aa62 MD |
1754 | pthread_mutex_lock(&ht->resize_mutex); |
1755 | _do_cds_lfht_resize(ht); | |
1756 | pthread_mutex_unlock(&ht->resize_mutex); | |
bec39940 | 1757 | ht->flavor->thread_online(); |
fa68aa62 MD |
1758 | } |
1759 | ||
1760 | static | |
1761 | void do_resize_cb(struct rcu_head *head) | |
1762 | { | |
1763 | struct rcu_resize_work *work = | |
1764 | caa_container_of(head, struct rcu_resize_work, head); | |
1765 | struct cds_lfht *ht = work->ht; | |
1766 | ||
bec39940 | 1767 | ht->flavor->thread_offline(); |
fa68aa62 MD |
1768 | pthread_mutex_lock(&ht->resize_mutex); |
1769 | _do_cds_lfht_resize(ht); | |
1770 | pthread_mutex_unlock(&ht->resize_mutex); | |
bec39940 | 1771 | ht->flavor->thread_online(); |
fa68aa62 MD |
1772 | poison_free(work); |
1773 | cmm_smp_mb(); /* finish resize before decrement */ | |
1774 | uatomic_dec(&ht->in_progress_resize); | |
1775 | } | |
1776 | ||
1777 | static | |
bec39940 | 1778 | void __cds_lfht_resize_lazy_launch(struct cds_lfht *ht) |
fa68aa62 MD |
1779 | { |
1780 | struct rcu_resize_work *work; | |
fa68aa62 | 1781 | |
fa68aa62 MD |
1782 | /* Store resize_target before read resize_initiated */ |
1783 | cmm_smp_mb(); | |
bec39940 | 1784 | if (!CMM_LOAD_SHARED(ht->resize_initiated)) { |
fa68aa62 | 1785 | uatomic_inc(&ht->in_progress_resize); |
d6b18934 DG |
1786 | cmm_smp_mb(); /* increment resize count before load destroy */ |
1787 | if (CMM_LOAD_SHARED(ht->in_progress_destroy)) { | |
1788 | uatomic_dec(&ht->in_progress_resize); | |
1789 | return; | |
1790 | } | |
fa68aa62 MD |
1791 | work = malloc(sizeof(*work)); |
1792 | work->ht = ht; | |
bec39940 DG |
1793 | ht->flavor->update_call_rcu(&work->head, do_resize_cb); |
1794 | CMM_STORE_SHARED(ht->resize_initiated, 1); | |
fa68aa62 MD |
1795 | } |
1796 | } | |
1797 | ||
bec39940 DG |
1798 | static |
1799 | void cds_lfht_resize_lazy_grow(struct cds_lfht *ht, unsigned long size, int growth) | |
1800 | { | |
1801 | unsigned long target_size = size << growth; | |
1802 | ||
1803 | target_size = min(target_size, ht->max_nr_buckets); | |
1804 | if (resize_target_grow(ht, target_size) >= target_size) | |
1805 | return; | |
1806 | ||
1807 | __cds_lfht_resize_lazy_launch(ht); | |
1808 | } | |
1809 | ||
1810 | /* | |
1811 | * We favor grow operations over shrink. A shrink operation never occurs | |
1812 | * if a grow operation is queued for lazy execution. A grow operation | |
1813 | * cancels any pending shrink lazy execution. | |
1814 | */ | |
fa68aa62 MD |
1815 | static |
1816 | void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, | |
1817 | unsigned long count) | |
1818 | { | |
fa68aa62 MD |
1819 | if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) |
1820 | return; | |
bec39940 DG |
1821 | count = max(count, MIN_TABLE_SIZE); |
1822 | count = min(count, ht->max_nr_buckets); | |
1823 | if (count == size) | |
1824 | return; /* Already the right size, no resize needed */ | |
1825 | if (count > size) { /* lazy grow */ | |
1826 | if (resize_target_grow(ht, count) >= count) | |
d6b18934 | 1827 | return; |
bec39940 DG |
1828 | } else { /* lazy shrink */ |
1829 | for (;;) { | |
1830 | unsigned long s; | |
1831 | ||
1832 | s = uatomic_cmpxchg(&ht->resize_target, size, count); | |
1833 | if (s == size) | |
1834 | break; /* no resize needed */ | |
1835 | if (s > size) | |
1836 | return; /* growing is/(was just) in progress */ | |
1837 | if (s <= count) | |
1838 | return; /* some other thread do shrink */ | |
1839 | size = s; | |
d6b18934 | 1840 | } |
fa68aa62 | 1841 | } |
bec39940 | 1842 | __cds_lfht_resize_lazy_launch(ht); |
fa68aa62 | 1843 | } |