rculfhash: use hash for index if !HAVE_SCHED_GETCPU
[urcu.git] / rculfhash.c
CommitLineData
5e28c532 1/*
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2 * rculfhash.c
3 *
1475579c 4 * Userspace RCU library - Lock-Free Resizable RCU Hash Table
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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
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21 */
22
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23/*
24 * Based on the following articles:
25 * - Ori Shalev and Nir Shavit. Split-ordered lists: Lock-free
26 * extensible hash tables. J. ACM 53, 3 (May 2006), 379-405.
27 * - Michael, M. M. High performance dynamic lock-free hash tables
28 * and list-based sets. In Proceedings of the fourteenth annual ACM
29 * symposium on Parallel algorithms and architectures, ACM Press,
30 * (2002), 73-82.
31 *
1475579c 32 * Some specificities of this Lock-Free Resizable RCU Hash Table
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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.
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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.
4c42f1b8 56 * - Split-counters are used to keep track of the number of
1475579c 57 * nodes within the hash table for automatic resize triggering.
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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.
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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.
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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
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94 * this order (except for order 0).
95 * - synchronzie_rcu is used to garbage-collect the old dummy node table.
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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.
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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 *
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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
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142 * 1 | 1 001 100 <-
143 * 2 | | 2 010 010 <- |
f6fdd688 144 * | | | 3 011 110 | <- |
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145 * 3 -> | | | 4 100 001 | |
146 * -> | | 5 101 101 |
147 * -> | 6 110 011
148 * -> 7 111 111
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149 */
150
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151#define _LGPL_SOURCE
152#include <stdlib.h>
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153#include <errno.h>
154#include <assert.h>
155#include <stdio.h>
abc490a1 156#include <stdint.h>
f000907d 157#include <string.h>
e0ba718a 158
15cfbec7 159#include "config.h"
2ed95849 160#include <urcu.h>
abc490a1 161#include <urcu-call-rcu.h>
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162#include <urcu/arch.h>
163#include <urcu/uatomic.h>
a42cc659 164#include <urcu/compiler.h>
abc490a1 165#include <urcu/rculfhash.h>
5e28c532 166#include <stdio.h>
464a1ec9 167#include <pthread.h>
44395fb7 168
f9830efd 169#ifdef DEBUG
f0c29ed7 170#define dbg_printf(fmt, args...) printf("[debug rculfhash] " fmt, ## args)
f9830efd 171#else
e753ff5a 172#define dbg_printf(fmt, args...)
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173#endif
174
f8994aee 175/*
4c42f1b8 176 * Split-counters lazily update the global counter each 1024
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177 * addition/removal. It automatically keeps track of resize required.
178 * We use the bucket length as indicator for need to expand for small
179 * tables and machines lacking per-cpu data suppport.
180 */
181#define COUNT_COMMIT_ORDER 10
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182#define CHAIN_LEN_TARGET 1
183#define CHAIN_LEN_RESIZE_THRESHOLD 3
2ed95849 184
cd95516d 185/*
76a73da8 186 * Define the minimum table size.
cd95516d 187 */
c9edd44a 188#define MIN_TABLE_SIZE 1
cd95516d 189
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190#if (CAA_BITS_PER_LONG == 32)
191#define MAX_TABLE_ORDER 32
192#else
193#define MAX_TABLE_ORDER 64
194#endif
195
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196/*
197 * Minimum number of dummy nodes to touch per thread to parallelize grow/shrink.
198 */
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199#define MIN_PARTITION_PER_THREAD_ORDER 12
200#define MIN_PARTITION_PER_THREAD (1UL << MIN_PARTITION_PER_THREAD_ORDER)
b7d619b0 201
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202#ifndef min
203#define min(a, b) ((a) < (b) ? (a) : (b))
204#endif
205
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206#ifndef max
207#define max(a, b) ((a) > (b) ? (a) : (b))
208#endif
2ed95849 209
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210/*
211 * The removed flag needs to be updated atomically with the pointer.
48ed1c18 212 * It indicates that no node must attach to the node scheduled for
b198f0fd 213 * removal, and that node garbage collection must be performed.
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214 * The dummy flag does not require to be updated atomically with the
215 * pointer, but it is added as a pointer low bit flag to save space.
216 */
d37166c6 217#define REMOVED_FLAG (1UL << 0)
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218#define DUMMY_FLAG (1UL << 1)
219#define FLAGS_MASK ((1UL << 2) - 1)
d37166c6 220
bb7b2f26 221/* Value of the end pointer. Should not interact with flags. */
f9c80341 222#define END_VALUE NULL
bb7b2f26 223
df44348d 224struct ht_items_count {
860d07e8 225 unsigned long add, del;
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226} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
227
1475579c 228struct rcu_level {
0d14ceb2 229 /* Note: manually update allocation length when adding a field */
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230 struct _cds_lfht_node nodes[0];
231};
232
395270b6 233struct rcu_table {
4105056a 234 unsigned long size; /* always a power of 2, shared (RCU) */
f9830efd 235 unsigned long resize_target;
11519af6 236 int resize_initiated;
4105056a 237 struct rcu_level *tbl[MAX_TABLE_ORDER];
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238};
239
14044b37 240struct cds_lfht {
4105056a 241 struct rcu_table t;
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242 cds_lfht_hash_fct hash_fct;
243 cds_lfht_compare_fct compare_fct;
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244 unsigned long min_alloc_order;
245 unsigned long min_alloc_size;
732ad076 246 unsigned long hash_seed;
b8af5011 247 int flags;
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248 /*
249 * We need to put the work threads offline (QSBR) when taking this
250 * mutex, because we use synchronize_rcu within this mutex critical
251 * section, which waits on read-side critical sections, and could
252 * therefore cause grace-period deadlock if we hold off RCU G.P.
253 * completion.
254 */
464a1ec9 255 pthread_mutex_t resize_mutex; /* resize mutex: add/del mutex */
33c7c748 256 unsigned int in_progress_resize, in_progress_destroy;
14044b37 257 void (*cds_lfht_call_rcu)(struct rcu_head *head,
abc490a1 258 void (*func)(struct rcu_head *head));
1475579c 259 void (*cds_lfht_synchronize_rcu)(void);
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260 void (*cds_lfht_rcu_read_lock)(void);
261 void (*cds_lfht_rcu_read_unlock)(void);
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262 void (*cds_lfht_rcu_thread_offline)(void);
263 void (*cds_lfht_rcu_thread_online)(void);
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264 void (*cds_lfht_rcu_register_thread)(void);
265 void (*cds_lfht_rcu_unregister_thread)(void);
266 pthread_attr_t *resize_attr; /* Resize threads attributes */
7de5ccfd 267 long count; /* global approximate item count */
4c42f1b8 268 struct ht_items_count *split_count; /* split item count */
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269};
270
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271struct rcu_resize_work {
272 struct rcu_head head;
14044b37 273 struct cds_lfht *ht;
abc490a1 274};
2ed95849 275
b7d619b0 276struct partition_resize_work {
1af6e26e 277 pthread_t thread_id;
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278 struct cds_lfht *ht;
279 unsigned long i, start, len;
280 void (*fct)(struct cds_lfht *ht, unsigned long i,
281 unsigned long start, unsigned long len);
282};
283
76a73da8 284static
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285void _cds_lfht_add(struct cds_lfht *ht,
286 unsigned long size,
287 struct cds_lfht_node *node,
288 struct cds_lfht_iter *unique_ret,
289 int dummy);
48ed1c18 290
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291/*
292 * Algorithm to reverse bits in a word by lookup table, extended to
293 * 64-bit words.
f9830efd 294 * Source:
abc490a1 295 * http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable
f9830efd 296 * Originally from Public Domain.
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297 */
298
299static const uint8_t BitReverseTable256[256] =
2ed95849 300{
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301#define R2(n) (n), (n) + 2*64, (n) + 1*64, (n) + 3*64
302#define R4(n) R2(n), R2((n) + 2*16), R2((n) + 1*16), R2((n) + 3*16)
303#define R6(n) R4(n), R4((n) + 2*4 ), R4((n) + 1*4 ), R4((n) + 3*4 )
304 R6(0), R6(2), R6(1), R6(3)
305};
306#undef R2
307#undef R4
308#undef R6
2ed95849 309
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310static
311uint8_t bit_reverse_u8(uint8_t v)
312{
313 return BitReverseTable256[v];
314}
ab7d5fc6 315
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316static __attribute__((unused))
317uint32_t bit_reverse_u32(uint32_t v)
318{
319 return ((uint32_t) bit_reverse_u8(v) << 24) |
320 ((uint32_t) bit_reverse_u8(v >> 8) << 16) |
321 ((uint32_t) bit_reverse_u8(v >> 16) << 8) |
322 ((uint32_t) bit_reverse_u8(v >> 24));
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323}
324
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325static __attribute__((unused))
326uint64_t bit_reverse_u64(uint64_t v)
2ed95849 327{
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328 return ((uint64_t) bit_reverse_u8(v) << 56) |
329 ((uint64_t) bit_reverse_u8(v >> 8) << 48) |
330 ((uint64_t) bit_reverse_u8(v >> 16) << 40) |
331 ((uint64_t) bit_reverse_u8(v >> 24) << 32) |
332 ((uint64_t) bit_reverse_u8(v >> 32) << 24) |
333 ((uint64_t) bit_reverse_u8(v >> 40) << 16) |
334 ((uint64_t) bit_reverse_u8(v >> 48) << 8) |
335 ((uint64_t) bit_reverse_u8(v >> 56));
336}
337
338static
339unsigned long bit_reverse_ulong(unsigned long v)
340{
341#if (CAA_BITS_PER_LONG == 32)
342 return bit_reverse_u32(v);
343#else
344 return bit_reverse_u64(v);
345#endif
346}
347
f9830efd 348/*
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349 * fls: returns the position of the most significant bit.
350 * Returns 0 if no bit is set, else returns the position of the most
351 * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit).
f9830efd 352 */
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353#if defined(__i386) || defined(__x86_64)
354static inline
355unsigned int fls_u32(uint32_t x)
f9830efd 356{
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357 int r;
358
359 asm("bsrl %1,%0\n\t"
360 "jnz 1f\n\t"
361 "movl $-1,%0\n\t"
362 "1:\n\t"
363 : "=r" (r) : "rm" (x));
364 return r + 1;
365}
366#define HAS_FLS_U32
367#endif
368
369#if defined(__x86_64)
370static inline
371unsigned int fls_u64(uint64_t x)
372{
373 long r;
374
375 asm("bsrq %1,%0\n\t"
376 "jnz 1f\n\t"
377 "movq $-1,%0\n\t"
378 "1:\n\t"
379 : "=r" (r) : "rm" (x));
380 return r + 1;
381}
382#define HAS_FLS_U64
383#endif
384
385#ifndef HAS_FLS_U64
386static __attribute__((unused))
387unsigned int fls_u64(uint64_t x)
388{
389 unsigned int r = 64;
390
391 if (!x)
392 return 0;
393
394 if (!(x & 0xFFFFFFFF00000000ULL)) {
395 x <<= 32;
396 r -= 32;
397 }
398 if (!(x & 0xFFFF000000000000ULL)) {
399 x <<= 16;
400 r -= 16;
401 }
402 if (!(x & 0xFF00000000000000ULL)) {
403 x <<= 8;
404 r -= 8;
405 }
406 if (!(x & 0xF000000000000000ULL)) {
407 x <<= 4;
408 r -= 4;
409 }
410 if (!(x & 0xC000000000000000ULL)) {
411 x <<= 2;
412 r -= 2;
413 }
414 if (!(x & 0x8000000000000000ULL)) {
415 x <<= 1;
416 r -= 1;
417 }
418 return r;
419}
420#endif
421
422#ifndef HAS_FLS_U32
423static __attribute__((unused))
424unsigned int fls_u32(uint32_t x)
425{
426 unsigned int r = 32;
f9830efd 427
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428 if (!x)
429 return 0;
430 if (!(x & 0xFFFF0000U)) {
431 x <<= 16;
432 r -= 16;
433 }
434 if (!(x & 0xFF000000U)) {
435 x <<= 8;
436 r -= 8;
437 }
438 if (!(x & 0xF0000000U)) {
439 x <<= 4;
440 r -= 4;
441 }
442 if (!(x & 0xC0000000U)) {
443 x <<= 2;
444 r -= 2;
445 }
446 if (!(x & 0x80000000U)) {
447 x <<= 1;
448 r -= 1;
449 }
450 return r;
451}
452#endif
453
454unsigned int fls_ulong(unsigned long x)
f9830efd 455{
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456#if (CAA_BITS_PER_lONG == 32)
457 return fls_u32(x);
458#else
459 return fls_u64(x);
460#endif
461}
f9830efd 462
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463/*
464 * Return the minimum order for which x <= (1UL << order).
465 * Return -1 if x is 0.
466 */
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467int get_count_order_u32(uint32_t x)
468{
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469 if (!x)
470 return -1;
24365af7 471
920f8ef6 472 return fls_u32(x - 1);
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473}
474
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475/*
476 * Return the minimum order for which x <= (1UL << order).
477 * Return -1 if x is 0.
478 */
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479int get_count_order_ulong(unsigned long x)
480{
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481 if (!x)
482 return -1;
24365af7 483
920f8ef6 484 return fls_ulong(x - 1);
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485}
486
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487#ifdef POISON_FREE
488#define poison_free(ptr) \
489 do { \
490 memset(ptr, 0x42, sizeof(*(ptr))); \
491 free(ptr); \
492 } while (0)
493#else
494#define poison_free(ptr) free(ptr)
495#endif
496
f9830efd 497static
4105056a 498void cds_lfht_resize_lazy(struct cds_lfht *ht, unsigned long size, int growth);
f9830efd 499
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500/*
501 * If the sched_getcpu() and sysconf(_SC_NPROCESSORS_CONF) calls are
502 * available, then we support hash table item accounting.
503 * In the unfortunate event the number of CPUs reported would be
504 * inaccurate, we use modulo arithmetic on the number of CPUs we got.
505 */
14360f1c 506#if defined(HAVE_SYSCONF)
df44348d 507
f8994aee 508static
4105056a 509void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size,
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510 unsigned long count);
511
df44348d 512static long nr_cpus_mask = -1;
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513static long split_count_mask = -1;
514
515static void ht_init_nr_cpus_mask(void)
516{
517 long maxcpus;
518
519 maxcpus = sysconf(_SC_NPROCESSORS_CONF);
520 if (maxcpus <= 0) {
521 nr_cpus_mask = -2;
522 return;
523 }
524 /*
525 * round up number of CPUs to next power of two, so we
526 * can use & for modulo.
527 */
528 maxcpus = 1UL << get_count_order_ulong(maxcpus);
529 nr_cpus_mask = maxcpus - 1;
530}
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531
532static
4c42f1b8 533struct ht_items_count *alloc_split_items_count(void)
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534{
535 struct ht_items_count *count;
536
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537 if (nr_cpus_mask == -1) {
538 ht_init_nr_cpus_mask();
539 split_count_mask = nr_cpus_mask;
df44348d 540 }
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541
542 if (split_count_mask < 0)
543 return NULL;
544 else
545 return calloc(split_count_mask + 1, sizeof(*count));
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546}
547
548static
4c42f1b8 549void free_split_items_count(struct ht_items_count *count)
df44348d 550{
98808fb1 551 poison_free(count);
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552}
553
14360f1c 554#if defined(HAVE_SCHED_GETCPU)
df44348d 555static
14360f1c 556int ht_get_split_count_index(unsigned long hash)
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557{
558 int cpu;
559
4c42f1b8 560 assert(split_count_mask >= 0);
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561 cpu = sched_getcpu();
562 if (unlikely(cpu < 0))
14360f1c 563 return hash & split_count_mask;
df44348d 564 else
4c42f1b8 565 return cpu & split_count_mask;
df44348d 566}
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567#else /* #if defined(HAVE_SCHED_GETCPU) */
568static
569int ht_get_split_count_index(unsigned long hash)
570{
571 return hash & split_count_mask;
572}
573#endif /* #else #if defined(HAVE_SCHED_GETCPU) */
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574
575static
14360f1c 576void ht_count_add(struct cds_lfht *ht, unsigned long size, unsigned long hash)
df44348d 577{
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578 unsigned long split_count;
579 int index;
df44348d 580
4c42f1b8 581 if (unlikely(!ht->split_count))
3171717f 582 return;
14360f1c 583 index = ht_get_split_count_index(hash);
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584 split_count = uatomic_add_return(&ht->split_count[index].add, 1);
585 if (unlikely(!(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) {
e3ecefd6 586 long count;
df44348d 587
4c42f1b8 588 dbg_printf("add split count %lu\n", split_count);
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589 count = uatomic_add_return(&ht->count,
590 1UL << COUNT_COMMIT_ORDER);
591 /* If power of 2 */
592 if (!(count & (count - 1))) {
4105056a 593 if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) < size)
f8994aee 594 return;
e3ecefd6 595 dbg_printf("add set global %ld\n", count);
4105056a 596 cds_lfht_resize_lazy_count(ht, size,
6ea6bc67 597 count >> (CHAIN_LEN_TARGET - 1));
df44348d
MD
598 }
599 }
600}
601
602static
14360f1c 603void ht_count_del(struct cds_lfht *ht, unsigned long size, unsigned long hash)
df44348d 604{
4c42f1b8
LJ
605 unsigned long split_count;
606 int index;
df44348d 607
4c42f1b8 608 if (unlikely(!ht->split_count))
3171717f 609 return;
14360f1c 610 index = ht_get_split_count_index(hash);
4c42f1b8
LJ
611 split_count = uatomic_add_return(&ht->split_count[index].del, 1);
612 if (unlikely(!(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) {
e3ecefd6 613 long count;
df44348d 614
4c42f1b8 615 dbg_printf("del split count %lu\n", split_count);
df44348d 616 count = uatomic_add_return(&ht->count,
3171717f 617 -(1UL << COUNT_COMMIT_ORDER));
df44348d
MD
618 /* If power of 2 */
619 if (!(count & (count - 1))) {
4105056a 620 if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) >= size)
f8994aee 621 return;
e3ecefd6
MD
622 dbg_printf("del set global %ld\n", count);
623 /*
c941bb9e 624 * Don't shrink table if the number of nodes is below a
e3ecefd6
MD
625 * certain threshold.
626 */
4c42f1b8 627 if (count < (1UL << COUNT_COMMIT_ORDER) * (split_count_mask + 1))
e3ecefd6 628 return;
4105056a 629 cds_lfht_resize_lazy_count(ht, size,
6ea6bc67 630 count >> (CHAIN_LEN_TARGET - 1));
df44348d
MD
631 }
632 }
633}
634
14360f1c 635#else /* #if defined(HAVE_SYSCONF) */
df44348d 636
91452a6a 637static const long nr_cpus_mask = -2;
4c42f1b8 638static const long split_count_mask = -2;
df44348d
MD
639
640static
4c42f1b8 641struct ht_items_count *alloc_split_items_count(void)
df44348d
MD
642{
643 return NULL;
644}
645
646static
4c42f1b8 647void free_split_items_count(struct ht_items_count *count)
df44348d
MD
648{
649}
650
651static
14360f1c 652void ht_count_add(struct cds_lfht *ht, unsigned long size, unsigned long hash)
df44348d
MD
653{
654}
655
656static
14360f1c 657void ht_count_del(struct cds_lfht *ht, unsigned long size, unsigned long hash)
df44348d
MD
658{
659}
660
14360f1c 661#endif /* #else #if defined(HAVE_SYSCONF) */
df44348d
MD
662
663
f9830efd 664static
4105056a 665void check_resize(struct cds_lfht *ht, unsigned long size, uint32_t chain_len)
f9830efd 666{
f8994aee
MD
667 unsigned long count;
668
b8af5011
MD
669 if (!(ht->flags & CDS_LFHT_AUTO_RESIZE))
670 return;
f8994aee
MD
671 count = uatomic_read(&ht->count);
672 /*
673 * Use bucket-local length for small table expand and for
674 * environments lacking per-cpu data support.
675 */
676 if (count >= (1UL << COUNT_COMMIT_ORDER))
677 return;
24365af7 678 if (chain_len > 100)
f0c29ed7 679 dbg_printf("WARNING: large chain length: %u.\n",
24365af7 680 chain_len);
3390d470 681 if (chain_len >= CHAIN_LEN_RESIZE_THRESHOLD)
4105056a 682 cds_lfht_resize_lazy(ht, size,
01370f0b 683 get_count_order_u32(chain_len - (CHAIN_LEN_TARGET - 1)));
f9830efd
MD
684}
685
abc490a1 686static
14044b37 687struct cds_lfht_node *clear_flag(struct cds_lfht_node *node)
abc490a1 688{
14044b37 689 return (struct cds_lfht_node *) (((unsigned long) node) & ~FLAGS_MASK);
abc490a1
MD
690}
691
692static
14044b37 693int is_removed(struct cds_lfht_node *node)
abc490a1 694{
d37166c6 695 return ((unsigned long) node) & REMOVED_FLAG;
abc490a1
MD
696}
697
698static
14044b37 699struct cds_lfht_node *flag_removed(struct cds_lfht_node *node)
abc490a1 700{
14044b37 701 return (struct cds_lfht_node *) (((unsigned long) node) | REMOVED_FLAG);
abc490a1
MD
702}
703
f5596c94 704static
14044b37 705int is_dummy(struct cds_lfht_node *node)
f5596c94
MD
706{
707 return ((unsigned long) node) & DUMMY_FLAG;
708}
709
710static
14044b37 711struct cds_lfht_node *flag_dummy(struct cds_lfht_node *node)
f5596c94 712{
14044b37 713 return (struct cds_lfht_node *) (((unsigned long) node) | DUMMY_FLAG);
f5596c94 714}
bb7b2f26
MD
715
716static
717struct cds_lfht_node *get_end(void)
718{
719 return (struct cds_lfht_node *) END_VALUE;
720}
721
722static
723int is_end(struct cds_lfht_node *node)
724{
725 return clear_flag(node) == (struct cds_lfht_node *) END_VALUE;
726}
727
abc490a1 728static
f9830efd 729unsigned long _uatomic_max(unsigned long *ptr, unsigned long v)
abc490a1
MD
730{
731 unsigned long old1, old2;
732
733 old1 = uatomic_read(ptr);
734 do {
735 old2 = old1;
736 if (old2 >= v)
f9830efd 737 return old2;
abc490a1 738 } while ((old1 = uatomic_cmpxchg(ptr, old2, v)) != old2);
f9830efd 739 return v;
abc490a1
MD
740}
741
f4a9cc0b
LJ
742static
743struct _cds_lfht_node *lookup_bucket(struct cds_lfht *ht, unsigned long size,
744 unsigned long hash)
745{
746 unsigned long index, order;
747
748 assert(size > 0);
749 index = hash & (size - 1);
ef6e6171
LJ
750
751 if (index < ht->min_alloc_size) {
752 dbg_printf("lookup hash %lu index %lu order 0 aridx 0\n",
753 hash, index);
754 return &ht->t.tbl[0]->nodes[index];
755 }
a4ea2223
LJ
756 /*
757 * equivalent to get_count_order_ulong(index + 1), but optimizes
758 * away the non-existing 0 special-case for
759 * get_count_order_ulong.
760 */
761 order = fls_ulong(index);
f4a9cc0b 762 dbg_printf("lookup hash %lu index %lu order %lu aridx %lu\n",
ef6e6171
LJ
763 hash, index, order, index & ((1UL << (order - 1)) - 1));
764 return &ht->t.tbl[order]->nodes[index & ((1UL << (order - 1)) - 1)];
f4a9cc0b
LJ
765}
766
273399de
MD
767/*
768 * Remove all logically deleted nodes from a bucket up to a certain node key.
769 */
770static
f9c80341 771void _cds_lfht_gc_bucket(struct cds_lfht_node *dummy, struct cds_lfht_node *node)
273399de 772{
14044b37 773 struct cds_lfht_node *iter_prev, *iter, *next, *new_next;
273399de 774
c90201ac
MD
775 assert(!is_dummy(dummy));
776 assert(!is_removed(dummy));
777 assert(!is_dummy(node));
778 assert(!is_removed(node));
273399de
MD
779 for (;;) {
780 iter_prev = dummy;
781 /* We can always skip the dummy node initially */
cc4fcb10 782 iter = rcu_dereference(iter_prev->p.next);
b4cb483f 783 assert(!is_removed(iter));
cc4fcb10 784 assert(iter_prev->p.reverse_hash <= node->p.reverse_hash);
bd4db153
MD
785 /*
786 * We should never be called with dummy (start of chain)
787 * and logically removed node (end of path compression
788 * marker) being the actual same node. This would be a
789 * bug in the algorithm implementation.
790 */
791 assert(dummy != node);
273399de 792 for (;;) {
bb7b2f26 793 if (unlikely(is_end(iter)))
f9c80341 794 return;
76412f24 795 if (likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash))
f9c80341 796 return;
cc4fcb10 797 next = rcu_dereference(clear_flag(iter)->p.next);
b198f0fd 798 if (likely(is_removed(next)))
273399de 799 break;
b453eae1 800 iter_prev = clear_flag(iter);
273399de
MD
801 iter = next;
802 }
b198f0fd 803 assert(!is_removed(iter));
f5596c94
MD
804 if (is_dummy(iter))
805 new_next = flag_dummy(clear_flag(next));
806 else
807 new_next = clear_flag(next);
808 (void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next);
273399de 809 }
f9c80341 810 return;
273399de
MD
811}
812
9357c415
MD
813static
814int _cds_lfht_replace(struct cds_lfht *ht, unsigned long size,
815 struct cds_lfht_node *old_node,
3fb86f26 816 struct cds_lfht_node *old_next,
9357c415
MD
817 struct cds_lfht_node *new_node)
818{
3fb86f26 819 struct cds_lfht_node *dummy, *ret_next;
9357c415 820 struct _cds_lfht_node *lookup;
9357c415
MD
821
822 if (!old_node) /* Return -ENOENT if asked to replace NULL node */
7801dadd 823 return -ENOENT;
9357c415
MD
824
825 assert(!is_removed(old_node));
826 assert(!is_dummy(old_node));
827 assert(!is_removed(new_node));
828 assert(!is_dummy(new_node));
829 assert(new_node != old_node);
3fb86f26 830 for (;;) {
9357c415 831 /* Insert after node to be replaced */
9357c415
MD
832 if (is_removed(old_next)) {
833 /*
834 * Too late, the old node has been removed under us
835 * between lookup and replace. Fail.
836 */
7801dadd 837 return -ENOENT;
9357c415
MD
838 }
839 assert(!is_dummy(old_next));
840 assert(new_node != clear_flag(old_next));
841 new_node->p.next = clear_flag(old_next);
842 /*
843 * Here is the whole trick for lock-free replace: we add
844 * the replacement node _after_ the node we want to
845 * replace by atomically setting its next pointer at the
846 * same time we set its removal flag. Given that
847 * the lookups/get next use an iterator aware of the
848 * next pointer, they will either skip the old node due
849 * to the removal flag and see the new node, or use
850 * the old node, but will not see the new one.
851 */
852 ret_next = uatomic_cmpxchg(&old_node->p.next,
853 old_next, flag_removed(new_node));
3fb86f26 854 if (ret_next == old_next)
7801dadd 855 break; /* We performed the replacement. */
3fb86f26
LJ
856 old_next = ret_next;
857 }
9357c415 858
9357c415
MD
859 /*
860 * Ensure that the old node is not visible to readers anymore:
861 * lookup for the node, and remove it (along with any other
862 * logically removed node) if found.
863 */
f4a9cc0b 864 lookup = lookup_bucket(ht, size, bit_reverse_ulong(old_node->p.reverse_hash));
9357c415
MD
865 dummy = (struct cds_lfht_node *) lookup;
866 _cds_lfht_gc_bucket(dummy, new_node);
7801dadd
LJ
867
868 assert(is_removed(rcu_dereference(old_node->p.next)));
869 return 0;
9357c415
MD
870}
871
83beee94
MD
872/*
873 * A non-NULL unique_ret pointer uses the "add unique" (or uniquify) add
874 * mode. A NULL unique_ret allows creation of duplicate keys.
875 */
abc490a1 876static
83beee94
MD
877void _cds_lfht_add(struct cds_lfht *ht,
878 unsigned long size,
879 struct cds_lfht_node *node,
880 struct cds_lfht_iter *unique_ret,
881 int dummy)
abc490a1 882{
14044b37 883 struct cds_lfht_node *iter_prev, *iter, *next, *new_node, *new_next,
960c9e4f 884 *return_node;
14044b37 885 struct _cds_lfht_node *lookup;
abc490a1 886
c90201ac
MD
887 assert(!is_dummy(node));
888 assert(!is_removed(node));
f4a9cc0b 889 lookup = lookup_bucket(ht, size, bit_reverse_ulong(node->p.reverse_hash));
abc490a1 890 for (;;) {
adc0de68 891 uint32_t chain_len = 0;
abc490a1 892
11519af6
MD
893 /*
894 * iter_prev points to the non-removed node prior to the
895 * insert location.
11519af6 896 */
14044b37 897 iter_prev = (struct cds_lfht_node *) lookup;
11519af6 898 /* We can always skip the dummy node initially */
cc4fcb10
MD
899 iter = rcu_dereference(iter_prev->p.next);
900 assert(iter_prev->p.reverse_hash <= node->p.reverse_hash);
abc490a1 901 for (;;) {
bb7b2f26 902 if (unlikely(is_end(iter)))
273399de 903 goto insert;
76412f24 904 if (likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash))
273399de 905 goto insert;
238cc06e 906
194fdbd1
LJ
907 /* dummy node is the first node of the identical-hash-value chain */
908 if (dummy && clear_flag(iter)->p.reverse_hash == node->p.reverse_hash)
909 goto insert;
238cc06e 910
cc4fcb10 911 next = rcu_dereference(clear_flag(iter)->p.next);
b198f0fd 912 if (unlikely(is_removed(next)))
9dba85be 913 goto gc_node;
238cc06e
LJ
914
915 /* uniquely add */
83beee94 916 if (unique_ret
1b81fe1a 917 && !is_dummy(next)
238cc06e
LJ
918 && clear_flag(iter)->p.reverse_hash == node->p.reverse_hash) {
919 struct cds_lfht_iter d_iter = { .node = node, .next = iter, };
920
921 /*
922 * uniquely adding inserts the node as the first
923 * node of the identical-hash-value node chain.
924 *
925 * This semantic ensures no duplicated keys
926 * should ever be observable in the table
927 * (including observe one node by one node
928 * by forward iterations)
929 */
930 cds_lfht_next_duplicate(ht, &d_iter);
931 if (!d_iter.node)
932 goto insert;
933
934 *unique_ret = d_iter;
83beee94 935 return;
48ed1c18 936 }
238cc06e 937
11519af6 938 /* Only account for identical reverse hash once */
24365af7
MD
939 if (iter_prev->p.reverse_hash != clear_flag(iter)->p.reverse_hash
940 && !is_dummy(next))
4105056a 941 check_resize(ht, size, ++chain_len);
11519af6 942 iter_prev = clear_flag(iter);
273399de 943 iter = next;
abc490a1 944 }
48ed1c18 945
273399de 946 insert:
7ec59d3b 947 assert(node != clear_flag(iter));
11519af6 948 assert(!is_removed(iter_prev));
c90201ac 949 assert(!is_removed(iter));
f000907d 950 assert(iter_prev != node);
f9c80341 951 if (!dummy)
1b81fe1a 952 node->p.next = clear_flag(iter);
f9c80341
MD
953 else
954 node->p.next = flag_dummy(clear_flag(iter));
f5596c94
MD
955 if (is_dummy(iter))
956 new_node = flag_dummy(node);
957 else
958 new_node = node;
cc4fcb10 959 if (uatomic_cmpxchg(&iter_prev->p.next, iter,
48ed1c18 960 new_node) != iter) {
273399de 961 continue; /* retry */
48ed1c18 962 } else {
83beee94 963 return_node = node;
960c9e4f 964 goto end;
48ed1c18
MD
965 }
966
9dba85be
MD
967 gc_node:
968 assert(!is_removed(iter));
f5596c94
MD
969 if (is_dummy(iter))
970 new_next = flag_dummy(clear_flag(next));
971 else
972 new_next = clear_flag(next);
973 (void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next);
273399de 974 /* retry */
464a1ec9 975 }
9357c415 976end:
83beee94
MD
977 if (unique_ret) {
978 unique_ret->node = return_node;
979 /* unique_ret->next left unset, never used. */
980 }
abc490a1 981}
464a1ec9 982
abc490a1 983static
860d07e8 984int _cds_lfht_del(struct cds_lfht *ht, unsigned long size,
4105056a 985 struct cds_lfht_node *node,
b198f0fd 986 int dummy_removal)
abc490a1 987{
14044b37
MD
988 struct cds_lfht_node *dummy, *next, *old;
989 struct _cds_lfht_node *lookup;
5e28c532 990
9357c415 991 if (!node) /* Return -ENOENT if asked to delete NULL node */
743f9143 992 return -ENOENT;
9357c415 993
7ec59d3b 994 /* logically delete the node */
c90201ac
MD
995 assert(!is_dummy(node));
996 assert(!is_removed(node));
cc4fcb10 997 old = rcu_dereference(node->p.next);
7ec59d3b 998 do {
48ed1c18
MD
999 struct cds_lfht_node *new_next;
1000
7ec59d3b 1001 next = old;
76412f24 1002 if (unlikely(is_removed(next)))
743f9143 1003 return -ENOENT;
1475579c
MD
1004 if (dummy_removal)
1005 assert(is_dummy(next));
1006 else
1007 assert(!is_dummy(next));
48ed1c18 1008 new_next = flag_removed(next);
48ed1c18 1009 old = uatomic_cmpxchg(&node->p.next, next, new_next);
7ec59d3b 1010 } while (old != next);
7ec59d3b 1011 /* We performed the (logical) deletion. */
7ec59d3b
MD
1012
1013 /*
1014 * Ensure that the node is not visible to readers anymore: lookup for
273399de
MD
1015 * the node, and remove it (along with any other logically removed node)
1016 * if found.
11519af6 1017 */
f4a9cc0b 1018 lookup = lookup_bucket(ht, size, bit_reverse_ulong(node->p.reverse_hash));
14044b37 1019 dummy = (struct cds_lfht_node *) lookup;
f9c80341 1020 _cds_lfht_gc_bucket(dummy, node);
743f9143
LJ
1021
1022 assert(is_removed(rcu_dereference(node->p.next)));
1023 return 0;
abc490a1 1024}
2ed95849 1025
b7d619b0
MD
1026static
1027void *partition_resize_thread(void *arg)
1028{
1029 struct partition_resize_work *work = arg;
1030
1031 work->ht->cds_lfht_rcu_register_thread();
1032 work->fct(work->ht, work->i, work->start, work->len);
1033 work->ht->cds_lfht_rcu_unregister_thread();
1034 return NULL;
1035}
1036
1037static
1038void partition_resize_helper(struct cds_lfht *ht, unsigned long i,
1039 unsigned long len,
1040 void (*fct)(struct cds_lfht *ht, unsigned long i,
1041 unsigned long start, unsigned long len))
1042{
1043 unsigned long partition_len;
1044 struct partition_resize_work *work;
6083a889
MD
1045 int thread, ret;
1046 unsigned long nr_threads;
b7d619b0 1047
6083a889
MD
1048 /*
1049 * Note: nr_cpus_mask + 1 is always power of 2.
1050 * We spawn just the number of threads we need to satisfy the minimum
1051 * partition size, up to the number of CPUs in the system.
1052 */
91452a6a
MD
1053 if (nr_cpus_mask > 0) {
1054 nr_threads = min(nr_cpus_mask + 1,
1055 len >> MIN_PARTITION_PER_THREAD_ORDER);
1056 } else {
1057 nr_threads = 1;
1058 }
6083a889
MD
1059 partition_len = len >> get_count_order_ulong(nr_threads);
1060 work = calloc(nr_threads, sizeof(*work));
b7d619b0 1061 assert(work);
6083a889
MD
1062 for (thread = 0; thread < nr_threads; thread++) {
1063 work[thread].ht = ht;
1064 work[thread].i = i;
1065 work[thread].len = partition_len;
1066 work[thread].start = thread * partition_len;
1067 work[thread].fct = fct;
1af6e26e 1068 ret = pthread_create(&(work[thread].thread_id), ht->resize_attr,
6083a889 1069 partition_resize_thread, &work[thread]);
b7d619b0
MD
1070 assert(!ret);
1071 }
6083a889 1072 for (thread = 0; thread < nr_threads; thread++) {
1af6e26e 1073 ret = pthread_join(work[thread].thread_id, NULL);
b7d619b0
MD
1074 assert(!ret);
1075 }
1076 free(work);
b7d619b0
MD
1077}
1078
e8de508e
MD
1079/*
1080 * Holding RCU read lock to protect _cds_lfht_add against memory
1081 * reclaim that could be performed by other call_rcu worker threads (ABA
1082 * problem).
9ee0fc9a 1083 *
b7d619b0 1084 * When we reach a certain length, we can split this population phase over
9ee0fc9a
MD
1085 * many worker threads, based on the number of CPUs available in the system.
1086 * This should therefore take care of not having the expand lagging behind too
1087 * many concurrent insertion threads by using the scheduler's ability to
1088 * schedule dummy node population fairly with insertions.
e8de508e 1089 */
4105056a 1090static
b7d619b0
MD
1091void init_table_populate_partition(struct cds_lfht *ht, unsigned long i,
1092 unsigned long start, unsigned long len)
4105056a
MD
1093{
1094 unsigned long j;
1095
5488222b 1096 assert(i > ht->min_alloc_order);
4105056a 1097 ht->cds_lfht_rcu_read_lock();
b7d619b0 1098 for (j = start; j < start + len; j++) {
4105056a
MD
1099 struct cds_lfht_node *new_node =
1100 (struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j];
1101
dc1da8f6 1102 dbg_printf("init populate: i %lu j %lu hash %lu\n",
4f6e90b7 1103 i, j, (1UL << (i - 1)) + j);
dc1da8f6 1104 new_node->p.reverse_hash =
4f6e90b7
LJ
1105 bit_reverse_ulong((1UL << (i - 1)) + j);
1106 _cds_lfht_add(ht, 1UL << (i - 1),
83beee94 1107 new_node, NULL, 1);
4105056a
MD
1108 }
1109 ht->cds_lfht_rcu_read_unlock();
b7d619b0
MD
1110}
1111
1112static
1113void init_table_populate(struct cds_lfht *ht, unsigned long i,
1114 unsigned long len)
1115{
1116 assert(nr_cpus_mask != -1);
6083a889 1117 if (nr_cpus_mask < 0 || len < 2 * MIN_PARTITION_PER_THREAD) {
b7d619b0
MD
1118 ht->cds_lfht_rcu_thread_online();
1119 init_table_populate_partition(ht, i, 0, len);
1120 ht->cds_lfht_rcu_thread_offline();
1121 return;
1122 }
1123 partition_resize_helper(ht, i, len, init_table_populate_partition);
4105056a
MD
1124}
1125
abc490a1 1126static
4105056a 1127void init_table(struct cds_lfht *ht,
93d46c39 1128 unsigned long first_order, unsigned long last_order)
24365af7 1129{
93d46c39 1130 unsigned long i;
24365af7 1131
93d46c39
LJ
1132 dbg_printf("init table: first_order %lu last_order %lu\n",
1133 first_order, last_order);
5488222b 1134 assert(first_order > ht->min_alloc_order);
93d46c39 1135 for (i = first_order; i <= last_order; i++) {
4105056a 1136 unsigned long len;
24365af7 1137
4f6e90b7 1138 len = 1UL << (i - 1);
f0c29ed7 1139 dbg_printf("init order %lu len: %lu\n", i, len);
4d676753
MD
1140
1141 /* Stop expand if the resize target changes under us */
4f6e90b7 1142 if (CMM_LOAD_SHARED(ht->t.resize_target) < (1UL << i))
4d676753
MD
1143 break;
1144
0d14ceb2 1145 ht->t.tbl[i] = calloc(1, len * sizeof(struct _cds_lfht_node));
b7d619b0 1146 assert(ht->t.tbl[i]);
4105056a 1147
4105056a 1148 /*
dc1da8f6
MD
1149 * Set all dummy nodes reverse hash values for a level and
1150 * link all dummy nodes into the table.
4105056a 1151 */
dc1da8f6 1152 init_table_populate(ht, i, len);
4105056a 1153
f9c80341
MD
1154 /*
1155 * Update table size.
1156 */
1157 cmm_smp_wmb(); /* populate data before RCU size */
4f6e90b7 1158 CMM_STORE_SHARED(ht->t.size, 1UL << i);
f9c80341 1159
4f6e90b7 1160 dbg_printf("init new size: %lu\n", 1UL << i);
4105056a
MD
1161 if (CMM_LOAD_SHARED(ht->in_progress_destroy))
1162 break;
1163 }
1164}
1165
e8de508e
MD
1166/*
1167 * Holding RCU read lock to protect _cds_lfht_remove against memory
1168 * reclaim that could be performed by other call_rcu worker threads (ABA
1169 * problem).
1170 * For a single level, we logically remove and garbage collect each node.
1171 *
1172 * As a design choice, we perform logical removal and garbage collection on a
1173 * node-per-node basis to simplify this algorithm. We also assume keeping good
1174 * cache locality of the operation would overweight possible performance gain
1175 * that could be achieved by batching garbage collection for multiple levels.
1176 * However, this would have to be justified by benchmarks.
1177 *
1178 * Concurrent removal and add operations are helping us perform garbage
1179 * collection of logically removed nodes. We guarantee that all logically
1180 * removed nodes have been garbage-collected (unlinked) before call_rcu is
1181 * invoked to free a hole level of dummy nodes (after a grace period).
1182 *
1183 * Logical removal and garbage collection can therefore be done in batch or on a
1184 * node-per-node basis, as long as the guarantee above holds.
9ee0fc9a 1185 *
b7d619b0
MD
1186 * When we reach a certain length, we can split this removal over many worker
1187 * threads, based on the number of CPUs available in the system. This should
1188 * take care of not letting resize process lag behind too many concurrent
9ee0fc9a 1189 * updater threads actively inserting into the hash table.
e8de508e 1190 */
4105056a 1191static
b7d619b0
MD
1192void remove_table_partition(struct cds_lfht *ht, unsigned long i,
1193 unsigned long start, unsigned long len)
4105056a
MD
1194{
1195 unsigned long j;
1196
5488222b 1197 assert(i > ht->min_alloc_order);
4105056a 1198 ht->cds_lfht_rcu_read_lock();
b7d619b0 1199 for (j = start; j < start + len; j++) {
4105056a
MD
1200 struct cds_lfht_node *fini_node =
1201 (struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j];
1202
1203 dbg_printf("remove entry: i %lu j %lu hash %lu\n",
4f6e90b7 1204 i, j, (1UL << (i - 1)) + j);
4105056a 1205 fini_node->p.reverse_hash =
4f6e90b7
LJ
1206 bit_reverse_ulong((1UL << (i - 1)) + j);
1207 (void) _cds_lfht_del(ht, 1UL << (i - 1), fini_node, 1);
abc490a1 1208 }
4105056a 1209 ht->cds_lfht_rcu_read_unlock();
b7d619b0
MD
1210}
1211
1212static
1213void remove_table(struct cds_lfht *ht, unsigned long i, unsigned long len)
1214{
1215
1216 assert(nr_cpus_mask != -1);
6083a889 1217 if (nr_cpus_mask < 0 || len < 2 * MIN_PARTITION_PER_THREAD) {
b7d619b0
MD
1218 ht->cds_lfht_rcu_thread_online();
1219 remove_table_partition(ht, i, 0, len);
1220 ht->cds_lfht_rcu_thread_offline();
1221 return;
1222 }
1223 partition_resize_helper(ht, i, len, remove_table_partition);
2ed95849
MD
1224}
1225
1475579c 1226static
4105056a 1227void fini_table(struct cds_lfht *ht,
93d46c39 1228 unsigned long first_order, unsigned long last_order)
1475579c 1229{
93d46c39 1230 long i;
0d14ceb2 1231 void *free_by_rcu = NULL;
1475579c 1232
93d46c39
LJ
1233 dbg_printf("fini table: first_order %lu last_order %lu\n",
1234 first_order, last_order);
5488222b 1235 assert(first_order > ht->min_alloc_order);
93d46c39 1236 for (i = last_order; i >= first_order; i--) {
4105056a 1237 unsigned long len;
1475579c 1238
4f6e90b7 1239 len = 1UL << (i - 1);
1475579c 1240 dbg_printf("fini order %lu len: %lu\n", i, len);
4105056a 1241
4d676753
MD
1242 /* Stop shrink if the resize target changes under us */
1243 if (CMM_LOAD_SHARED(ht->t.resize_target) > (1UL << (i - 1)))
1244 break;
1245
1246 cmm_smp_wmb(); /* populate data before RCU size */
1247 CMM_STORE_SHARED(ht->t.size, 1UL << (i - 1));
1248
1249 /*
1250 * We need to wait for all add operations to reach Q.S. (and
1251 * thus use the new table for lookups) before we can start
1252 * releasing the old dummy nodes. Otherwise their lookup will
1253 * return a logically removed node as insert position.
1254 */
1255 ht->cds_lfht_synchronize_rcu();
0d14ceb2
LJ
1256 if (free_by_rcu)
1257 free(free_by_rcu);
4d676753 1258
21263e21 1259 /*
4105056a
MD
1260 * Set "removed" flag in dummy nodes about to be removed.
1261 * Unlink all now-logically-removed dummy node pointers.
1262 * Concurrent add/remove operation are helping us doing
1263 * the gc.
21263e21 1264 */
4105056a
MD
1265 remove_table(ht, i, len);
1266
0d14ceb2 1267 free_by_rcu = ht->t.tbl[i];
4105056a
MD
1268
1269 dbg_printf("fini new size: %lu\n", 1UL << i);
1475579c
MD
1270 if (CMM_LOAD_SHARED(ht->in_progress_destroy))
1271 break;
1272 }
0d14ceb2
LJ
1273
1274 if (free_by_rcu) {
1275 ht->cds_lfht_synchronize_rcu();
1276 free(free_by_rcu);
1277 }
1475579c
MD
1278}
1279
ff0d69de
LJ
1280static
1281void cds_lfht_create_dummy(struct cds_lfht *ht, unsigned long size)
1282{
1283 struct _cds_lfht_node *prev, *node;
1284 unsigned long order, len, i, j;
1285
5488222b 1286 ht->t.tbl[0] = calloc(1, ht->min_alloc_size * sizeof(struct _cds_lfht_node));
ff0d69de
LJ
1287 assert(ht->t.tbl[0]);
1288
1289 dbg_printf("create dummy: order %lu index %lu hash %lu\n", 0, 0, 0);
1290 ht->t.tbl[0]->nodes[0].next = flag_dummy(get_end());
1291 ht->t.tbl[0]->nodes[0].reverse_hash = 0;
1292
1293 for (order = 1; order < get_count_order_ulong(size) + 1; order++) {
1294 len = 1UL << (order - 1);
5488222b 1295 if (order <= ht->min_alloc_order) {
eb631bf2 1296 ht->t.tbl[order] = (struct rcu_level *) (ht->t.tbl[0]->nodes + len);
5488222b
LJ
1297 } else {
1298 ht->t.tbl[order] = calloc(1, len * sizeof(struct _cds_lfht_node));
1299 assert(ht->t.tbl[order]);
1300 }
ff0d69de
LJ
1301
1302 i = 0;
1303 prev = ht->t.tbl[i]->nodes;
1304 for (j = 0; j < len; j++) {
1305 if (j & (j - 1)) { /* Between power of 2 */
1306 prev++;
1307 } else if (j) { /* At each power of 2 */
1308 i++;
1309 prev = ht->t.tbl[i]->nodes;
1310 }
1311
1312 node = &ht->t.tbl[order]->nodes[j];
1313 dbg_printf("create dummy: order %lu index %lu hash %lu\n",
1314 order, j, j + len);
1315 node->next = prev->next;
1316 assert(is_dummy(node->next));
1317 node->reverse_hash = bit_reverse_ulong(j + len);
1318 prev->next = flag_dummy((struct cds_lfht_node *)node);
1319 }
1320 }
1321}
1322
7a9dcf9b 1323struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct,
14044b37
MD
1324 cds_lfht_compare_fct compare_fct,
1325 unsigned long hash_seed,
1326 unsigned long init_size,
5488222b 1327 unsigned long min_alloc_size,
b8af5011 1328 int flags,
14044b37 1329 void (*cds_lfht_call_rcu)(struct rcu_head *head,
1475579c 1330 void (*func)(struct rcu_head *head)),
01dbfa62
MD
1331 void (*cds_lfht_synchronize_rcu)(void),
1332 void (*cds_lfht_rcu_read_lock)(void),
5f511391
MD
1333 void (*cds_lfht_rcu_read_unlock)(void),
1334 void (*cds_lfht_rcu_thread_offline)(void),
b7d619b0
MD
1335 void (*cds_lfht_rcu_thread_online)(void),
1336 void (*cds_lfht_rcu_register_thread)(void),
1337 void (*cds_lfht_rcu_unregister_thread)(void),
1338 pthread_attr_t *attr)
abc490a1 1339{
14044b37 1340 struct cds_lfht *ht;
24365af7 1341 unsigned long order;
abc490a1 1342
5488222b
LJ
1343 /* min_alloc_size must be power of two */
1344 if (!min_alloc_size || (min_alloc_size & (min_alloc_size - 1)))
1345 return NULL;
8129be4e 1346 /* init_size must be power of two */
5488222b 1347 if (!init_size || (init_size & (init_size - 1)))
8129be4e 1348 return NULL;
5488222b
LJ
1349 min_alloc_size = max(min_alloc_size, MIN_TABLE_SIZE);
1350 init_size = max(init_size, min_alloc_size);
14044b37 1351 ht = calloc(1, sizeof(struct cds_lfht));
b7d619b0 1352 assert(ht);
abc490a1 1353 ht->hash_fct = hash_fct;
732ad076
MD
1354 ht->compare_fct = compare_fct;
1355 ht->hash_seed = hash_seed;
14044b37 1356 ht->cds_lfht_call_rcu = cds_lfht_call_rcu;
1475579c 1357 ht->cds_lfht_synchronize_rcu = cds_lfht_synchronize_rcu;
01dbfa62
MD
1358 ht->cds_lfht_rcu_read_lock = cds_lfht_rcu_read_lock;
1359 ht->cds_lfht_rcu_read_unlock = cds_lfht_rcu_read_unlock;
5f511391
MD
1360 ht->cds_lfht_rcu_thread_offline = cds_lfht_rcu_thread_offline;
1361 ht->cds_lfht_rcu_thread_online = cds_lfht_rcu_thread_online;
b7d619b0
MD
1362 ht->cds_lfht_rcu_register_thread = cds_lfht_rcu_register_thread;
1363 ht->cds_lfht_rcu_unregister_thread = cds_lfht_rcu_unregister_thread;
1364 ht->resize_attr = attr;
4c42f1b8 1365 ht->split_count = alloc_split_items_count();
abc490a1
MD
1366 /* this mutex should not nest in read-side C.S. */
1367 pthread_mutex_init(&ht->resize_mutex, NULL);
b8af5011 1368 ht->flags = flags;
5488222b 1369 order = get_count_order_ulong(init_size);
93d46c39 1370 ht->t.resize_target = 1UL << order;
ff0d69de
LJ
1371 cds_lfht_create_dummy(ht, 1UL << order);
1372 ht->t.size = 1UL << order;
5488222b
LJ
1373 ht->min_alloc_size = min_alloc_size;
1374 ht->min_alloc_order = get_count_order_ulong(min_alloc_size);
abc490a1
MD
1375 return ht;
1376}
1377
adc0de68
MD
1378void cds_lfht_lookup(struct cds_lfht *ht, void *key, size_t key_len,
1379 struct cds_lfht_iter *iter)
2ed95849 1380{
bb7b2f26 1381 struct cds_lfht_node *node, *next, *dummy_node;
14044b37 1382 struct _cds_lfht_node *lookup;
f4a9cc0b 1383 unsigned long hash, reverse_hash, size;
2ed95849 1384
732ad076 1385 hash = ht->hash_fct(key, key_len, ht->hash_seed);
abc490a1 1386 reverse_hash = bit_reverse_ulong(hash);
464a1ec9 1387
4105056a 1388 size = rcu_dereference(ht->t.size);
f4a9cc0b 1389 lookup = lookup_bucket(ht, size, hash);
bb7b2f26
MD
1390 dummy_node = (struct cds_lfht_node *) lookup;
1391 /* We can always skip the dummy node initially */
1392 node = rcu_dereference(dummy_node->p.next);
bb7b2f26 1393 node = clear_flag(node);
2ed95849 1394 for (;;) {
bb7b2f26 1395 if (unlikely(is_end(node))) {
96ad1112 1396 node = next = NULL;
abc490a1 1397 break;
bb7b2f26 1398 }
cc4fcb10 1399 if (unlikely(node->p.reverse_hash > reverse_hash)) {
96ad1112 1400 node = next = NULL;
abc490a1 1401 break;
2ed95849 1402 }
1b81fe1a 1403 next = rcu_dereference(node->p.next);
adc0de68 1404 if (likely(!is_removed(next))
1b81fe1a 1405 && !is_dummy(next)
ae450da3 1406 && clear_flag(node)->p.reverse_hash == reverse_hash
49c2e2d6 1407 && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) {
273399de 1408 break;
2ed95849 1409 }
1b81fe1a 1410 node = clear_flag(next);
2ed95849 1411 }
1b81fe1a 1412 assert(!node || !is_dummy(rcu_dereference(node->p.next)));
adc0de68
MD
1413 iter->node = node;
1414 iter->next = next;
abc490a1 1415}
e0ba718a 1416
3883c0e5 1417void cds_lfht_next_duplicate(struct cds_lfht *ht, struct cds_lfht_iter *iter)
a481e5ff 1418{
adc0de68 1419 struct cds_lfht_node *node, *next;
a481e5ff
MD
1420 unsigned long reverse_hash;
1421 void *key;
1422 size_t key_len;
1423
adc0de68 1424 node = iter->node;
a481e5ff
MD
1425 reverse_hash = node->p.reverse_hash;
1426 key = node->key;
1427 key_len = node->key_len;
adc0de68 1428 next = iter->next;
a481e5ff
MD
1429 node = clear_flag(next);
1430
1431 for (;;) {
bb7b2f26 1432 if (unlikely(is_end(node))) {
96ad1112 1433 node = next = NULL;
a481e5ff 1434 break;
bb7b2f26 1435 }
a481e5ff 1436 if (unlikely(node->p.reverse_hash > reverse_hash)) {
96ad1112 1437 node = next = NULL;
a481e5ff
MD
1438 break;
1439 }
1440 next = rcu_dereference(node->p.next);
adc0de68 1441 if (likely(!is_removed(next))
a481e5ff
MD
1442 && !is_dummy(next)
1443 && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) {
1444 break;
1445 }
1446 node = clear_flag(next);
1447 }
1448 assert(!node || !is_dummy(rcu_dereference(node->p.next)));
adc0de68
MD
1449 iter->node = node;
1450 iter->next = next;
a481e5ff
MD
1451}
1452
4e9b9fbf
MD
1453void cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_iter *iter)
1454{
1455 struct cds_lfht_node *node, *next;
1456
853395e1 1457 node = clear_flag(iter->next);
4e9b9fbf
MD
1458 for (;;) {
1459 if (unlikely(is_end(node))) {
1460 node = next = NULL;
1461 break;
1462 }
1463 next = rcu_dereference(node->p.next);
1464 if (likely(!is_removed(next))
1465 && !is_dummy(next)) {
1466 break;
1467 }
1468 node = clear_flag(next);
1469 }
1470 assert(!node || !is_dummy(rcu_dereference(node->p.next)));
1471 iter->node = node;
1472 iter->next = next;
1473}
1474
1475void cds_lfht_first(struct cds_lfht *ht, struct cds_lfht_iter *iter)
1476{
1477 struct _cds_lfht_node *lookup;
1478
1479 /*
1480 * Get next after first dummy node. The first dummy node is the
1481 * first node of the linked list.
1482 */
1483 lookup = &ht->t.tbl[0]->nodes[0];
853395e1 1484 iter->next = lookup->next;
4e9b9fbf
MD
1485 cds_lfht_next(ht, iter);
1486}
1487
14044b37 1488void cds_lfht_add(struct cds_lfht *ht, struct cds_lfht_node *node)
abc490a1 1489{
4105056a 1490 unsigned long hash, size;
ab7d5fc6 1491
49c2e2d6 1492 hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed);
cc4fcb10 1493 node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash);
2ed95849 1494
4105056a 1495 size = rcu_dereference(ht->t.size);
83beee94 1496 _cds_lfht_add(ht, size, node, NULL, 0);
14360f1c 1497 ht_count_add(ht, size, hash);
3eca1b8c
MD
1498}
1499
14044b37 1500struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht,
48ed1c18 1501 struct cds_lfht_node *node)
3eca1b8c 1502{
4105056a 1503 unsigned long hash, size;
83beee94 1504 struct cds_lfht_iter iter;
3eca1b8c 1505
49c2e2d6 1506 hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed);
cc4fcb10 1507 node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash);
3eca1b8c 1508
4105056a 1509 size = rcu_dereference(ht->t.size);
83beee94
MD
1510 _cds_lfht_add(ht, size, node, &iter, 0);
1511 if (iter.node == node)
14360f1c 1512 ht_count_add(ht, size, hash);
83beee94 1513 return iter.node;
2ed95849
MD
1514}
1515
9357c415 1516struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht,
48ed1c18
MD
1517 struct cds_lfht_node *node)
1518{
1519 unsigned long hash, size;
83beee94 1520 struct cds_lfht_iter iter;
48ed1c18
MD
1521
1522 hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed);
1523 node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash);
1524
1525 size = rcu_dereference(ht->t.size);
83beee94
MD
1526 for (;;) {
1527 _cds_lfht_add(ht, size, node, &iter, 0);
1528 if (iter.node == node) {
14360f1c 1529 ht_count_add(ht, size, hash);
83beee94
MD
1530 return NULL;
1531 }
1532
1533 if (!_cds_lfht_replace(ht, size, iter.node, iter.next, node))
1534 return iter.node;
1535 }
48ed1c18
MD
1536}
1537
9357c415
MD
1538int cds_lfht_replace(struct cds_lfht *ht, struct cds_lfht_iter *old_iter,
1539 struct cds_lfht_node *new_node)
1540{
1541 unsigned long size;
1542
1543 size = rcu_dereference(ht->t.size);
1544 return _cds_lfht_replace(ht, size, old_iter->node, old_iter->next,
1545 new_node);
1546}
1547
1548int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_iter *iter)
2ed95849 1549{
14360f1c 1550 unsigned long size, hash;
df44348d 1551 int ret;
abc490a1 1552
4105056a 1553 size = rcu_dereference(ht->t.size);
9357c415 1554 ret = _cds_lfht_del(ht, size, iter->node, 0);
14360f1c
LJ
1555 if (!ret) {
1556 hash = bit_reverse_ulong(iter->node->p.reverse_hash);
1557 ht_count_del(ht, size, hash);
1558 }
df44348d 1559 return ret;
2ed95849 1560}
ab7d5fc6 1561
abc490a1 1562static
14044b37 1563int cds_lfht_delete_dummy(struct cds_lfht *ht)
674f7a69 1564{
14044b37
MD
1565 struct cds_lfht_node *node;
1566 struct _cds_lfht_node *lookup;
4105056a 1567 unsigned long order, i, size;
674f7a69 1568
abc490a1 1569 /* Check that the table is empty */
4105056a 1570 lookup = &ht->t.tbl[0]->nodes[0];
14044b37 1571 node = (struct cds_lfht_node *) lookup;
abc490a1 1572 do {
1b81fe1a
MD
1573 node = clear_flag(node)->p.next;
1574 if (!is_dummy(node))
abc490a1 1575 return -EPERM;
273399de 1576 assert(!is_removed(node));
bb7b2f26 1577 } while (!is_end(node));
4105056a
MD
1578 /*
1579 * size accessed without rcu_dereference because hash table is
1580 * being destroyed.
1581 */
1582 size = ht->t.size;
abc490a1 1583 /* Internal sanity check: all nodes left should be dummy */
4105056a 1584 for (order = 0; order < get_count_order_ulong(size) + 1; order++) {
24365af7
MD
1585 unsigned long len;
1586
1587 len = !order ? 1 : 1UL << (order - 1);
1588 for (i = 0; i < len; i++) {
f0c29ed7 1589 dbg_printf("delete order %lu i %lu hash %lu\n",
24365af7 1590 order, i,
4105056a
MD
1591 bit_reverse_ulong(ht->t.tbl[order]->nodes[i].reverse_hash));
1592 assert(is_dummy(ht->t.tbl[order]->nodes[i].next));
24365af7 1593 }
5488222b
LJ
1594
1595 if (order == ht->min_alloc_order)
1596 poison_free(ht->t.tbl[0]);
1597 else if (order > ht->min_alloc_order)
1598 poison_free(ht->t.tbl[order]);
1599 /* Nothing to delete for order < ht->min_alloc_order */
674f7a69 1600 }
abc490a1 1601 return 0;
674f7a69
MD
1602}
1603
1604/*
1605 * Should only be called when no more concurrent readers nor writers can
1606 * possibly access the table.
1607 */
b7d619b0 1608int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr)
674f7a69 1609{
5e28c532
MD
1610 int ret;
1611
848d4088 1612 /* Wait for in-flight resize operations to complete */
24953e08
MD
1613 _CMM_STORE_SHARED(ht->in_progress_destroy, 1);
1614 cmm_smp_mb(); /* Store destroy before load resize */
848d4088
MD
1615 while (uatomic_read(&ht->in_progress_resize))
1616 poll(NULL, 0, 100); /* wait for 100ms */
14044b37 1617 ret = cds_lfht_delete_dummy(ht);
abc490a1
MD
1618 if (ret)
1619 return ret;
4c42f1b8 1620 free_split_items_count(ht->split_count);
b7d619b0
MD
1621 if (attr)
1622 *attr = ht->resize_attr;
98808fb1 1623 poison_free(ht);
5e28c532 1624 return ret;
674f7a69
MD
1625}
1626
14044b37 1627void cds_lfht_count_nodes(struct cds_lfht *ht,
d933dd0e 1628 long *approx_before,
273399de 1629 unsigned long *count,
973e5e1b 1630 unsigned long *removed,
d933dd0e 1631 long *approx_after)
273399de 1632{
14044b37
MD
1633 struct cds_lfht_node *node, *next;
1634 struct _cds_lfht_node *lookup;
24365af7 1635 unsigned long nr_dummy = 0;
273399de 1636
7ed7682f 1637 *approx_before = 0;
4c42f1b8 1638 if (split_count_mask >= 0) {
973e5e1b
MD
1639 int i;
1640
4c42f1b8
LJ
1641 for (i = 0; i < split_count_mask + 1; i++) {
1642 *approx_before += uatomic_read(&ht->split_count[i].add);
1643 *approx_before -= uatomic_read(&ht->split_count[i].del);
973e5e1b
MD
1644 }
1645 }
1646
273399de
MD
1647 *count = 0;
1648 *removed = 0;
1649
24365af7 1650 /* Count non-dummy nodes in the table */
4105056a 1651 lookup = &ht->t.tbl[0]->nodes[0];
14044b37 1652 node = (struct cds_lfht_node *) lookup;
273399de 1653 do {
cc4fcb10 1654 next = rcu_dereference(node->p.next);
b198f0fd 1655 if (is_removed(next)) {
973e5e1b
MD
1656 if (!is_dummy(next))
1657 (*removed)++;
1658 else
1659 (nr_dummy)++;
1b81fe1a 1660 } else if (!is_dummy(next))
273399de 1661 (*count)++;
24365af7
MD
1662 else
1663 (nr_dummy)++;
273399de 1664 node = clear_flag(next);
bb7b2f26 1665 } while (!is_end(node));
f0c29ed7 1666 dbg_printf("number of dummy nodes: %lu\n", nr_dummy);
7ed7682f 1667 *approx_after = 0;
4c42f1b8 1668 if (split_count_mask >= 0) {
973e5e1b
MD
1669 int i;
1670
4c42f1b8
LJ
1671 for (i = 0; i < split_count_mask + 1; i++) {
1672 *approx_after += uatomic_read(&ht->split_count[i].add);
1673 *approx_after -= uatomic_read(&ht->split_count[i].del);
973e5e1b
MD
1674 }
1675 }
273399de
MD
1676}
1677
1475579c 1678/* called with resize mutex held */
abc490a1 1679static
4105056a 1680void _do_cds_lfht_grow(struct cds_lfht *ht,
1475579c 1681 unsigned long old_size, unsigned long new_size)
abc490a1 1682{
1475579c 1683 unsigned long old_order, new_order;
1475579c 1684
93d46c39
LJ
1685 old_order = get_count_order_ulong(old_size);
1686 new_order = get_count_order_ulong(new_size);
1a401918
LJ
1687 dbg_printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n",
1688 old_size, old_order, new_size, new_order);
1475579c 1689 assert(new_size > old_size);
93d46c39 1690 init_table(ht, old_order + 1, new_order);
abc490a1
MD
1691}
1692
1693/* called with resize mutex held */
1694static
4105056a 1695void _do_cds_lfht_shrink(struct cds_lfht *ht,
1475579c 1696 unsigned long old_size, unsigned long new_size)
464a1ec9 1697{
1475579c 1698 unsigned long old_order, new_order;
464a1ec9 1699
5488222b 1700 new_size = max(new_size, ht->min_alloc_size);
93d46c39
LJ
1701 old_order = get_count_order_ulong(old_size);
1702 new_order = get_count_order_ulong(new_size);
1a401918
LJ
1703 dbg_printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n",
1704 old_size, old_order, new_size, new_order);
1475579c 1705 assert(new_size < old_size);
1475579c 1706
4105056a 1707 /* Remove and unlink all dummy nodes to remove. */
93d46c39 1708 fini_table(ht, new_order + 1, old_order);
464a1ec9
MD
1709}
1710
1475579c
MD
1711
1712/* called with resize mutex held */
1713static
1714void _do_cds_lfht_resize(struct cds_lfht *ht)
1715{
1716 unsigned long new_size, old_size;
4105056a
MD
1717
1718 /*
1719 * Resize table, re-do if the target size has changed under us.
1720 */
1721 do {
d2be3620
MD
1722 assert(uatomic_read(&ht->in_progress_resize));
1723 if (CMM_LOAD_SHARED(ht->in_progress_destroy))
1724 break;
4105056a
MD
1725 ht->t.resize_initiated = 1;
1726 old_size = ht->t.size;
1727 new_size = CMM_LOAD_SHARED(ht->t.resize_target);
1728 if (old_size < new_size)
1729 _do_cds_lfht_grow(ht, old_size, new_size);
1730 else if (old_size > new_size)
1731 _do_cds_lfht_shrink(ht, old_size, new_size);
1732 ht->t.resize_initiated = 0;
1733 /* write resize_initiated before read resize_target */
1734 cmm_smp_mb();
4d676753 1735 } while (ht->t.size != CMM_LOAD_SHARED(ht->t.resize_target));
1475579c
MD
1736}
1737
abc490a1 1738static
4105056a 1739unsigned long resize_target_update(struct cds_lfht *ht, unsigned long size,
f9830efd 1740 int growth_order)
464a1ec9 1741{
4105056a
MD
1742 return _uatomic_max(&ht->t.resize_target,
1743 size << growth_order);
464a1ec9
MD
1744}
1745
1475579c 1746static
4105056a 1747void resize_target_update_count(struct cds_lfht *ht,
b8af5011 1748 unsigned long count)
1475579c 1749{
5488222b 1750 count = max(count, ht->min_alloc_size);
4105056a 1751 uatomic_set(&ht->t.resize_target, count);
1475579c
MD
1752}
1753
1754void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size)
464a1ec9 1755{
4105056a
MD
1756 resize_target_update_count(ht, new_size);
1757 CMM_STORE_SHARED(ht->t.resize_initiated, 1);
5f511391 1758 ht->cds_lfht_rcu_thread_offline();
1475579c
MD
1759 pthread_mutex_lock(&ht->resize_mutex);
1760 _do_cds_lfht_resize(ht);
1761 pthread_mutex_unlock(&ht->resize_mutex);
5f511391 1762 ht->cds_lfht_rcu_thread_online();
abc490a1 1763}
464a1ec9 1764
abc490a1
MD
1765static
1766void do_resize_cb(struct rcu_head *head)
1767{
1768 struct rcu_resize_work *work =
1769 caa_container_of(head, struct rcu_resize_work, head);
14044b37 1770 struct cds_lfht *ht = work->ht;
abc490a1 1771
5f511391 1772 ht->cds_lfht_rcu_thread_offline();
abc490a1 1773 pthread_mutex_lock(&ht->resize_mutex);
14044b37 1774 _do_cds_lfht_resize(ht);
abc490a1 1775 pthread_mutex_unlock(&ht->resize_mutex);
5f511391 1776 ht->cds_lfht_rcu_thread_online();
98808fb1 1777 poison_free(work);
848d4088
MD
1778 cmm_smp_mb(); /* finish resize before decrement */
1779 uatomic_dec(&ht->in_progress_resize);
464a1ec9
MD
1780}
1781
abc490a1 1782static
4105056a 1783void cds_lfht_resize_lazy(struct cds_lfht *ht, unsigned long size, int growth)
ab7d5fc6 1784{
abc490a1 1785 struct rcu_resize_work *work;
f9830efd 1786 unsigned long target_size;
abc490a1 1787
4105056a
MD
1788 target_size = resize_target_update(ht, size, growth);
1789 /* Store resize_target before read resize_initiated */
1790 cmm_smp_mb();
1791 if (!CMM_LOAD_SHARED(ht->t.resize_initiated) && size < target_size) {
848d4088 1792 uatomic_inc(&ht->in_progress_resize);
59290e9d 1793 cmm_smp_mb(); /* increment resize count before load destroy */
ed35e6d8
MD
1794 if (CMM_LOAD_SHARED(ht->in_progress_destroy)) {
1795 uatomic_dec(&ht->in_progress_resize);
59290e9d 1796 return;
ed35e6d8 1797 }
f9830efd
MD
1798 work = malloc(sizeof(*work));
1799 work->ht = ht;
14044b37 1800 ht->cds_lfht_call_rcu(&work->head, do_resize_cb);
4105056a 1801 CMM_STORE_SHARED(ht->t.resize_initiated, 1);
f9830efd 1802 }
ab7d5fc6 1803}
3171717f 1804
14360f1c 1805#if defined(HAVE_SYSCONF)
f8994aee 1806
3171717f 1807static
4105056a 1808void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size,
3171717f
MD
1809 unsigned long count)
1810{
1811 struct rcu_resize_work *work;
3171717f 1812
b8af5011
MD
1813 if (!(ht->flags & CDS_LFHT_AUTO_RESIZE))
1814 return;
4105056a
MD
1815 resize_target_update_count(ht, count);
1816 /* Store resize_target before read resize_initiated */
1817 cmm_smp_mb();
1818 if (!CMM_LOAD_SHARED(ht->t.resize_initiated)) {
3171717f 1819 uatomic_inc(&ht->in_progress_resize);
59290e9d 1820 cmm_smp_mb(); /* increment resize count before load destroy */
ed35e6d8
MD
1821 if (CMM_LOAD_SHARED(ht->in_progress_destroy)) {
1822 uatomic_dec(&ht->in_progress_resize);
59290e9d 1823 return;
ed35e6d8 1824 }
3171717f
MD
1825 work = malloc(sizeof(*work));
1826 work->ht = ht;
1827 ht->cds_lfht_call_rcu(&work->head, do_resize_cb);
4105056a 1828 CMM_STORE_SHARED(ht->t.resize_initiated, 1);
3171717f
MD
1829 }
1830}
f8994aee
MD
1831
1832#endif
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