rculfhash,test: add memory_backend argument
[urcu.git] / rculfhash.c
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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>
0dcf4847 7 * Copyright 2011 - Lai Jiangshan <laijs@cn.fujitsu.com>
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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
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22 */
23
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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 *
1475579c 33 * Some specificities of this Lock-Free Resizable RCU Hash Table
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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.
1ee8f000 49 * - An index of bucket nodes is kept. These bucket nodes are the hash
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50 * table "buckets", and they are also chained together in the
51 * split-ordered list, which allows recursive expansion.
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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.
4c42f1b8 57 * - Split-counters are used to keep track of the number of
1475579c 58 * nodes within the hash table for automatic resize triggering.
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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
1ee8f000 78 * an invariant node (the start-of-bucket bucket node) up to the
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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.
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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.
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90 * - A RCU "order table" indexed by log2(hash index) is copied and
91 * expanded by the resize operation. This order table allows finding
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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
93d46c39 95 * this order (except for order 0).
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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
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98 * hash table nodes. These tables are invariant after they are
99 * populated into the hash table.
93d46c39 100 *
1ee8f000 101 * Bucket node tables:
93d46c39 102 *
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103 * hash table hash table the last all bucket node tables
104 * order size bucket node 0 1 2 3 4 5 6(index)
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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 *
1ee8f000 114 * When growing/shrinking, we only focus on the last bucket node table
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115 * which size is (!order ? 1 : (1 << (order -1))).
116 *
117 * Example for growing/shrinking:
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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
93d46c39 120 *
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121 * A bit of ascii art explanation:
122 *
123 * Order index is the off-by-one compare to the actual power of 2 because
124 * we use index 0 to deal with the 0 special-case.
125 *
126 * This shows the nodes for a small table ordered by reversed bits:
127 *
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
137 *
138 * This shows the nodes in order of non-reversed bits, linked by
139 * reversed-bit order.
140 *
141 * order bits reverse
142 * 0 0 000 000
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143 * 1 | 1 001 100 <-
144 * 2 | | 2 010 010 <- |
f6fdd688 145 * | | | 3 011 110 | <- |
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146 * 3 -> | | | 4 100 001 | |
147 * -> | | 5 101 101 |
148 * -> | 6 110 011
149 * -> 7 111 111
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150 */
151
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152#define _LGPL_SOURCE
153#include <stdlib.h>
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154#include <errno.h>
155#include <assert.h>
156#include <stdio.h>
abc490a1 157#include <stdint.h>
f000907d 158#include <string.h>
e0ba718a 159
15cfbec7 160#include "config.h"
2ed95849 161#include <urcu.h>
abc490a1 162#include <urcu-call-rcu.h>
7b17c13e 163#include <urcu-flavor.h>
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164#include <urcu/arch.h>
165#include <urcu/uatomic.h>
a42cc659 166#include <urcu/compiler.h>
abc490a1 167#include <urcu/rculfhash.h>
0b6aa001 168#include <rculfhash-internal.h>
5e28c532 169#include <stdio.h>
464a1ec9 170#include <pthread.h>
44395fb7 171
f8994aee 172/*
4c42f1b8 173 * Split-counters lazily update the global counter each 1024
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174 * addition/removal. It automatically keeps track of resize required.
175 * We use the bucket length as indicator for need to expand for small
176 * tables and machines lacking per-cpu data suppport.
177 */
178#define COUNT_COMMIT_ORDER 10
4ddbb355 179#define DEFAULT_SPLIT_COUNT_MASK 0xFUL
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180#define CHAIN_LEN_TARGET 1
181#define CHAIN_LEN_RESIZE_THRESHOLD 3
2ed95849 182
cd95516d 183/*
76a73da8 184 * Define the minimum table size.
cd95516d 185 */
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186#define MIN_TABLE_ORDER 0
187#define MIN_TABLE_SIZE (1UL << MIN_TABLE_ORDER)
cd95516d 188
b7d619b0 189/*
1ee8f000 190 * Minimum number of bucket nodes to touch per thread to parallelize grow/shrink.
b7d619b0 191 */
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192#define MIN_PARTITION_PER_THREAD_ORDER 12
193#define MIN_PARTITION_PER_THREAD (1UL << MIN_PARTITION_PER_THREAD_ORDER)
b7d619b0 194
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195/*
196 * The removed flag needs to be updated atomically with the pointer.
48ed1c18 197 * It indicates that no node must attach to the node scheduled for
b198f0fd 198 * removal, and that node garbage collection must be performed.
1ee8f000 199 * The bucket flag does not require to be updated atomically with the
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200 * pointer, but it is added as a pointer low bit flag to save space.
201 */
d37166c6 202#define REMOVED_FLAG (1UL << 0)
1ee8f000 203#define BUCKET_FLAG (1UL << 1)
b198f0fd 204#define FLAGS_MASK ((1UL << 2) - 1)
d37166c6 205
bb7b2f26 206/* Value of the end pointer. Should not interact with flags. */
f9c80341 207#define END_VALUE NULL
bb7b2f26 208
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209/*
210 * ht_items_count: Split-counters counting the number of node addition
211 * and removal in the table. Only used if the CDS_LFHT_ACCOUNTING flag
212 * is set at hash table creation.
213 *
214 * These are free-running counters, never reset to zero. They count the
215 * number of add/remove, and trigger every (1 << COUNT_COMMIT_ORDER)
216 * operations to update the global counter. We choose a power-of-2 value
217 * for the trigger to deal with 32 or 64-bit overflow of the counter.
218 */
df44348d 219struct ht_items_count {
860d07e8 220 unsigned long add, del;
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221} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
222
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223/*
224 * rcu_resize_work: Contains arguments passed to RCU worker thread
225 * responsible for performing lazy resize.
226 */
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227struct rcu_resize_work {
228 struct rcu_head head;
14044b37 229 struct cds_lfht *ht;
abc490a1 230};
2ed95849 231
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232/*
233 * partition_resize_work: Contains arguments passed to worker threads
234 * executing the hash table resize on partitions of the hash table
235 * assigned to each processor's worker thread.
236 */
b7d619b0 237struct partition_resize_work {
1af6e26e 238 pthread_t thread_id;
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239 struct cds_lfht *ht;
240 unsigned long i, start, len;
241 void (*fct)(struct cds_lfht *ht, unsigned long i,
242 unsigned long start, unsigned long len);
243};
244
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245/*
246 * Algorithm to reverse bits in a word by lookup table, extended to
247 * 64-bit words.
f9830efd 248 * Source:
abc490a1 249 * http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable
f9830efd 250 * Originally from Public Domain.
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251 */
252
253static const uint8_t BitReverseTable256[256] =
2ed95849 254{
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255#define R2(n) (n), (n) + 2*64, (n) + 1*64, (n) + 3*64
256#define R4(n) R2(n), R2((n) + 2*16), R2((n) + 1*16), R2((n) + 3*16)
257#define R6(n) R4(n), R4((n) + 2*4 ), R4((n) + 1*4 ), R4((n) + 3*4 )
258 R6(0), R6(2), R6(1), R6(3)
259};
260#undef R2
261#undef R4
262#undef R6
2ed95849 263
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264static
265uint8_t bit_reverse_u8(uint8_t v)
266{
267 return BitReverseTable256[v];
268}
ab7d5fc6 269
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270static __attribute__((unused))
271uint32_t bit_reverse_u32(uint32_t v)
272{
273 return ((uint32_t) bit_reverse_u8(v) << 24) |
274 ((uint32_t) bit_reverse_u8(v >> 8) << 16) |
275 ((uint32_t) bit_reverse_u8(v >> 16) << 8) |
276 ((uint32_t) bit_reverse_u8(v >> 24));
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277}
278
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279static __attribute__((unused))
280uint64_t bit_reverse_u64(uint64_t v)
2ed95849 281{
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282 return ((uint64_t) bit_reverse_u8(v) << 56) |
283 ((uint64_t) bit_reverse_u8(v >> 8) << 48) |
284 ((uint64_t) bit_reverse_u8(v >> 16) << 40) |
285 ((uint64_t) bit_reverse_u8(v >> 24) << 32) |
286 ((uint64_t) bit_reverse_u8(v >> 32) << 24) |
287 ((uint64_t) bit_reverse_u8(v >> 40) << 16) |
288 ((uint64_t) bit_reverse_u8(v >> 48) << 8) |
289 ((uint64_t) bit_reverse_u8(v >> 56));
290}
291
292static
293unsigned long bit_reverse_ulong(unsigned long v)
294{
295#if (CAA_BITS_PER_LONG == 32)
296 return bit_reverse_u32(v);
297#else
298 return bit_reverse_u64(v);
299#endif
300}
301
f9830efd 302/*
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303 * fls: returns the position of the most significant bit.
304 * Returns 0 if no bit is set, else returns the position of the most
305 * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit).
f9830efd 306 */
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307#if defined(__i386) || defined(__x86_64)
308static inline
309unsigned int fls_u32(uint32_t x)
f9830efd 310{
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311 int r;
312
313 asm("bsrl %1,%0\n\t"
314 "jnz 1f\n\t"
315 "movl $-1,%0\n\t"
316 "1:\n\t"
317 : "=r" (r) : "rm" (x));
318 return r + 1;
319}
320#define HAS_FLS_U32
321#endif
322
323#if defined(__x86_64)
324static inline
325unsigned int fls_u64(uint64_t x)
326{
327 long r;
328
329 asm("bsrq %1,%0\n\t"
330 "jnz 1f\n\t"
331 "movq $-1,%0\n\t"
332 "1:\n\t"
333 : "=r" (r) : "rm" (x));
334 return r + 1;
335}
336#define HAS_FLS_U64
337#endif
338
339#ifndef HAS_FLS_U64
340static __attribute__((unused))
341unsigned int fls_u64(uint64_t x)
342{
343 unsigned int r = 64;
344
345 if (!x)
346 return 0;
347
348 if (!(x & 0xFFFFFFFF00000000ULL)) {
349 x <<= 32;
350 r -= 32;
351 }
352 if (!(x & 0xFFFF000000000000ULL)) {
353 x <<= 16;
354 r -= 16;
355 }
356 if (!(x & 0xFF00000000000000ULL)) {
357 x <<= 8;
358 r -= 8;
359 }
360 if (!(x & 0xF000000000000000ULL)) {
361 x <<= 4;
362 r -= 4;
363 }
364 if (!(x & 0xC000000000000000ULL)) {
365 x <<= 2;
366 r -= 2;
367 }
368 if (!(x & 0x8000000000000000ULL)) {
369 x <<= 1;
370 r -= 1;
371 }
372 return r;
373}
374#endif
375
376#ifndef HAS_FLS_U32
377static __attribute__((unused))
378unsigned int fls_u32(uint32_t x)
379{
380 unsigned int r = 32;
f9830efd 381
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382 if (!x)
383 return 0;
384 if (!(x & 0xFFFF0000U)) {
385 x <<= 16;
386 r -= 16;
387 }
388 if (!(x & 0xFF000000U)) {
389 x <<= 8;
390 r -= 8;
391 }
392 if (!(x & 0xF0000000U)) {
393 x <<= 4;
394 r -= 4;
395 }
396 if (!(x & 0xC0000000U)) {
397 x <<= 2;
398 r -= 2;
399 }
400 if (!(x & 0x80000000U)) {
401 x <<= 1;
402 r -= 1;
403 }
404 return r;
405}
406#endif
407
408unsigned int fls_ulong(unsigned long x)
f9830efd 409{
6887cc5e 410#if (CAA_BITS_PER_LONG == 32)
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411 return fls_u32(x);
412#else
413 return fls_u64(x);
414#endif
415}
f9830efd 416
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417/*
418 * Return the minimum order for which x <= (1UL << order).
419 * Return -1 if x is 0.
420 */
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421int get_count_order_u32(uint32_t x)
422{
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423 if (!x)
424 return -1;
24365af7 425
920f8ef6 426 return fls_u32(x - 1);
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427}
428
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429/*
430 * Return the minimum order for which x <= (1UL << order).
431 * Return -1 if x is 0.
432 */
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433int get_count_order_ulong(unsigned long x)
434{
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435 if (!x)
436 return -1;
24365af7 437
920f8ef6 438 return fls_ulong(x - 1);
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439}
440
441static
ab65b890 442void cds_lfht_resize_lazy_grow(struct cds_lfht *ht, unsigned long size, int growth);
f9830efd 443
f8994aee 444static
4105056a 445void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size,
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446 unsigned long count);
447
df44348d 448static long nr_cpus_mask = -1;
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449static long split_count_mask = -1;
450
4ddbb355 451#if defined(HAVE_SYSCONF)
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452static void ht_init_nr_cpus_mask(void)
453{
454 long maxcpus;
455
456 maxcpus = sysconf(_SC_NPROCESSORS_CONF);
457 if (maxcpus <= 0) {
458 nr_cpus_mask = -2;
459 return;
460 }
461 /*
462 * round up number of CPUs to next power of two, so we
463 * can use & for modulo.
464 */
465 maxcpus = 1UL << get_count_order_ulong(maxcpus);
466 nr_cpus_mask = maxcpus - 1;
467}
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468#else /* #if defined(HAVE_SYSCONF) */
469static void ht_init_nr_cpus_mask(void)
470{
471 nr_cpus_mask = -2;
472}
473#endif /* #else #if defined(HAVE_SYSCONF) */
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474
475static
5afadd12 476void alloc_split_items_count(struct cds_lfht *ht)
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477{
478 struct ht_items_count *count;
479
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480 if (nr_cpus_mask == -1) {
481 ht_init_nr_cpus_mask();
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482 if (nr_cpus_mask < 0)
483 split_count_mask = DEFAULT_SPLIT_COUNT_MASK;
484 else
485 split_count_mask = nr_cpus_mask;
df44348d 486 }
4c42f1b8 487
4ddbb355 488 assert(split_count_mask >= 0);
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489
490 if (ht->flags & CDS_LFHT_ACCOUNTING) {
491 ht->split_count = calloc(split_count_mask + 1, sizeof(*count));
492 assert(ht->split_count);
493 } else {
494 ht->split_count = NULL;
495 }
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496}
497
498static
5afadd12 499void free_split_items_count(struct cds_lfht *ht)
df44348d 500{
5afadd12 501 poison_free(ht->split_count);
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502}
503
14360f1c 504#if defined(HAVE_SCHED_GETCPU)
df44348d 505static
14360f1c 506int ht_get_split_count_index(unsigned long hash)
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507{
508 int cpu;
509
4c42f1b8 510 assert(split_count_mask >= 0);
df44348d 511 cpu = sched_getcpu();
8ed51e04 512 if (caa_unlikely(cpu < 0))
14360f1c 513 return hash & split_count_mask;
df44348d 514 else
4c42f1b8 515 return cpu & split_count_mask;
df44348d 516}
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517#else /* #if defined(HAVE_SCHED_GETCPU) */
518static
519int ht_get_split_count_index(unsigned long hash)
520{
521 return hash & split_count_mask;
522}
523#endif /* #else #if defined(HAVE_SCHED_GETCPU) */
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524
525static
14360f1c 526void ht_count_add(struct cds_lfht *ht, unsigned long size, unsigned long hash)
df44348d 527{
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528 unsigned long split_count;
529 int index;
314558bf 530 long count;
df44348d 531
8ed51e04 532 if (caa_unlikely(!ht->split_count))
3171717f 533 return;
14360f1c 534 index = ht_get_split_count_index(hash);
4c42f1b8 535 split_count = uatomic_add_return(&ht->split_count[index].add, 1);
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536 if (caa_likely(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))
537 return;
538 /* Only if number of add multiple of 1UL << COUNT_COMMIT_ORDER */
539
540 dbg_printf("add split count %lu\n", split_count);
541 count = uatomic_add_return(&ht->count,
542 1UL << COUNT_COMMIT_ORDER);
4c299dcb 543 if (caa_likely(count & (count - 1)))
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544 return;
545 /* Only if global count is power of 2 */
546
547 if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) < size)
548 return;
549 dbg_printf("add set global %ld\n", count);
550 cds_lfht_resize_lazy_count(ht, size,
551 count >> (CHAIN_LEN_TARGET - 1));
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552}
553
554static
14360f1c 555void ht_count_del(struct cds_lfht *ht, unsigned long size, unsigned long hash)
df44348d 556{
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557 unsigned long split_count;
558 int index;
314558bf 559 long count;
df44348d 560
8ed51e04 561 if (caa_unlikely(!ht->split_count))
3171717f 562 return;
14360f1c 563 index = ht_get_split_count_index(hash);
4c42f1b8 564 split_count = uatomic_add_return(&ht->split_count[index].del, 1);
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565 if (caa_likely(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))
566 return;
567 /* Only if number of deletes multiple of 1UL << COUNT_COMMIT_ORDER */
568
569 dbg_printf("del split count %lu\n", split_count);
570 count = uatomic_add_return(&ht->count,
571 -(1UL << COUNT_COMMIT_ORDER));
4c299dcb 572 if (caa_likely(count & (count - 1)))
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573 return;
574 /* Only if global count is power of 2 */
575
576 if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) >= size)
577 return;
578 dbg_printf("del set global %ld\n", count);
579 /*
580 * Don't shrink table if the number of nodes is below a
581 * certain threshold.
582 */
583 if (count < (1UL << COUNT_COMMIT_ORDER) * (split_count_mask + 1))
584 return;
585 cds_lfht_resize_lazy_count(ht, size,
586 count >> (CHAIN_LEN_TARGET - 1));
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587}
588
f9830efd 589static
4105056a 590void check_resize(struct cds_lfht *ht, unsigned long size, uint32_t chain_len)
f9830efd 591{
f8994aee
MD
592 unsigned long count;
593
b8af5011
MD
594 if (!(ht->flags & CDS_LFHT_AUTO_RESIZE))
595 return;
f8994aee
MD
596 count = uatomic_read(&ht->count);
597 /*
598 * Use bucket-local length for small table expand and for
599 * environments lacking per-cpu data support.
600 */
601 if (count >= (1UL << COUNT_COMMIT_ORDER))
602 return;
24365af7 603 if (chain_len > 100)
f0c29ed7 604 dbg_printf("WARNING: large chain length: %u.\n",
24365af7 605 chain_len);
3390d470 606 if (chain_len >= CHAIN_LEN_RESIZE_THRESHOLD)
ab65b890 607 cds_lfht_resize_lazy_grow(ht, size,
01370f0b 608 get_count_order_u32(chain_len - (CHAIN_LEN_TARGET - 1)));
f9830efd
MD
609}
610
abc490a1 611static
14044b37 612struct cds_lfht_node *clear_flag(struct cds_lfht_node *node)
abc490a1 613{
14044b37 614 return (struct cds_lfht_node *) (((unsigned long) node) & ~FLAGS_MASK);
abc490a1
MD
615}
616
617static
14044b37 618int is_removed(struct cds_lfht_node *node)
abc490a1 619{
d37166c6 620 return ((unsigned long) node) & REMOVED_FLAG;
abc490a1
MD
621}
622
623static
14044b37 624struct cds_lfht_node *flag_removed(struct cds_lfht_node *node)
abc490a1 625{
14044b37 626 return (struct cds_lfht_node *) (((unsigned long) node) | REMOVED_FLAG);
abc490a1
MD
627}
628
f5596c94 629static
1ee8f000 630int is_bucket(struct cds_lfht_node *node)
f5596c94 631{
1ee8f000 632 return ((unsigned long) node) & BUCKET_FLAG;
f5596c94
MD
633}
634
635static
1ee8f000 636struct cds_lfht_node *flag_bucket(struct cds_lfht_node *node)
f5596c94 637{
1ee8f000 638 return (struct cds_lfht_node *) (((unsigned long) node) | BUCKET_FLAG);
f5596c94 639}
bb7b2f26
MD
640
641static
642struct cds_lfht_node *get_end(void)
643{
644 return (struct cds_lfht_node *) END_VALUE;
645}
646
647static
648int is_end(struct cds_lfht_node *node)
649{
650 return clear_flag(node) == (struct cds_lfht_node *) END_VALUE;
651}
652
abc490a1 653static
ab65b890
LJ
654unsigned long _uatomic_xchg_monotonic_increase(unsigned long *ptr,
655 unsigned long v)
abc490a1
MD
656{
657 unsigned long old1, old2;
658
659 old1 = uatomic_read(ptr);
660 do {
661 old2 = old1;
662 if (old2 >= v)
f9830efd 663 return old2;
abc490a1 664 } while ((old1 = uatomic_cmpxchg(ptr, old2, v)) != old2);
ab65b890 665 return old2;
abc490a1
MD
666}
667
48f1b16d
LJ
668static
669void cds_lfht_alloc_bucket_table(struct cds_lfht *ht, unsigned long order)
670{
0b6aa001 671 return ht->mm->alloc_bucket_table(ht, order);
48f1b16d
LJ
672}
673
674/*
675 * cds_lfht_free_bucket_table() should be called with decreasing order.
676 * When cds_lfht_free_bucket_table(0) is called, it means the whole
677 * lfht is destroyed.
678 */
679static
680void cds_lfht_free_bucket_table(struct cds_lfht *ht, unsigned long order)
681{
0b6aa001 682 return ht->mm->free_bucket_table(ht, order);
48f1b16d
LJ
683}
684
9d72a73f
LJ
685static inline
686struct cds_lfht_node *bucket_at(struct cds_lfht *ht, unsigned long index)
f4a9cc0b 687{
0b6aa001 688 return ht->bucket_at(ht, index);
f4a9cc0b
LJ
689}
690
9d72a73f
LJ
691static inline
692struct cds_lfht_node *lookup_bucket(struct cds_lfht *ht, unsigned long size,
693 unsigned long hash)
694{
695 assert(size > 0);
696 return bucket_at(ht, hash & (size - 1));
697}
698
273399de
MD
699/*
700 * Remove all logically deleted nodes from a bucket up to a certain node key.
701 */
702static
1ee8f000 703void _cds_lfht_gc_bucket(struct cds_lfht_node *bucket, struct cds_lfht_node *node)
273399de 704{
14044b37 705 struct cds_lfht_node *iter_prev, *iter, *next, *new_next;
273399de 706
1ee8f000
LJ
707 assert(!is_bucket(bucket));
708 assert(!is_removed(bucket));
709 assert(!is_bucket(node));
c90201ac 710 assert(!is_removed(node));
273399de 711 for (;;) {
1ee8f000
LJ
712 iter_prev = bucket;
713 /* We can always skip the bucket node initially */
04db56f8 714 iter = rcu_dereference(iter_prev->next);
b4cb483f 715 assert(!is_removed(iter));
04db56f8 716 assert(iter_prev->reverse_hash <= node->reverse_hash);
bd4db153 717 /*
1ee8f000 718 * We should never be called with bucket (start of chain)
bd4db153
MD
719 * and logically removed node (end of path compression
720 * marker) being the actual same node. This would be a
721 * bug in the algorithm implementation.
722 */
1ee8f000 723 assert(bucket != node);
273399de 724 for (;;) {
8ed51e04 725 if (caa_unlikely(is_end(iter)))
f9c80341 726 return;
04db56f8 727 if (caa_likely(clear_flag(iter)->reverse_hash > node->reverse_hash))
f9c80341 728 return;
04db56f8 729 next = rcu_dereference(clear_flag(iter)->next);
8ed51e04 730 if (caa_likely(is_removed(next)))
273399de 731 break;
b453eae1 732 iter_prev = clear_flag(iter);
273399de
MD
733 iter = next;
734 }
b198f0fd 735 assert(!is_removed(iter));
1ee8f000
LJ
736 if (is_bucket(iter))
737 new_next = flag_bucket(clear_flag(next));
f5596c94
MD
738 else
739 new_next = clear_flag(next);
04db56f8 740 (void) uatomic_cmpxchg(&iter_prev->next, iter, new_next);
273399de 741 }
f9c80341 742 return;
273399de
MD
743}
744
9357c415
MD
745static
746int _cds_lfht_replace(struct cds_lfht *ht, unsigned long size,
747 struct cds_lfht_node *old_node,
3fb86f26 748 struct cds_lfht_node *old_next,
9357c415
MD
749 struct cds_lfht_node *new_node)
750{
04db56f8 751 struct cds_lfht_node *bucket, *ret_next;
9357c415
MD
752
753 if (!old_node) /* Return -ENOENT if asked to replace NULL node */
7801dadd 754 return -ENOENT;
9357c415
MD
755
756 assert(!is_removed(old_node));
1ee8f000 757 assert(!is_bucket(old_node));
9357c415 758 assert(!is_removed(new_node));
1ee8f000 759 assert(!is_bucket(new_node));
9357c415 760 assert(new_node != old_node);
3fb86f26 761 for (;;) {
9357c415 762 /* Insert after node to be replaced */
9357c415
MD
763 if (is_removed(old_next)) {
764 /*
765 * Too late, the old node has been removed under us
766 * between lookup and replace. Fail.
767 */
7801dadd 768 return -ENOENT;
9357c415 769 }
1ee8f000 770 assert(!is_bucket(old_next));
9357c415 771 assert(new_node != clear_flag(old_next));
04db56f8 772 new_node->next = clear_flag(old_next);
9357c415
MD
773 /*
774 * Here is the whole trick for lock-free replace: we add
775 * the replacement node _after_ the node we want to
776 * replace by atomically setting its next pointer at the
777 * same time we set its removal flag. Given that
778 * the lookups/get next use an iterator aware of the
779 * next pointer, they will either skip the old node due
780 * to the removal flag and see the new node, or use
781 * the old node, but will not see the new one.
782 */
04db56f8 783 ret_next = uatomic_cmpxchg(&old_node->next,
9357c415 784 old_next, flag_removed(new_node));
3fb86f26 785 if (ret_next == old_next)
7801dadd 786 break; /* We performed the replacement. */
3fb86f26
LJ
787 old_next = ret_next;
788 }
9357c415 789
9357c415
MD
790 /*
791 * Ensure that the old node is not visible to readers anymore:
792 * lookup for the node, and remove it (along with any other
793 * logically removed node) if found.
794 */
04db56f8
LJ
795 bucket = lookup_bucket(ht, size, bit_reverse_ulong(old_node->reverse_hash));
796 _cds_lfht_gc_bucket(bucket, new_node);
7801dadd 797
04db56f8 798 assert(is_removed(rcu_dereference(old_node->next)));
7801dadd 799 return 0;
9357c415
MD
800}
801
83beee94
MD
802/*
803 * A non-NULL unique_ret pointer uses the "add unique" (or uniquify) add
804 * mode. A NULL unique_ret allows creation of duplicate keys.
805 */
abc490a1 806static
83beee94 807void _cds_lfht_add(struct cds_lfht *ht,
0422d92c 808 cds_lfht_match_fct match,
996ff57c 809 const void *key,
83beee94
MD
810 unsigned long size,
811 struct cds_lfht_node *node,
812 struct cds_lfht_iter *unique_ret,
1ee8f000 813 int bucket_flag)
abc490a1 814{
14044b37 815 struct cds_lfht_node *iter_prev, *iter, *next, *new_node, *new_next,
960c9e4f 816 *return_node;
04db56f8 817 struct cds_lfht_node *bucket;
abc490a1 818
1ee8f000 819 assert(!is_bucket(node));
c90201ac 820 assert(!is_removed(node));
04db56f8 821 bucket = lookup_bucket(ht, size, bit_reverse_ulong(node->reverse_hash));
abc490a1 822 for (;;) {
adc0de68 823 uint32_t chain_len = 0;
abc490a1 824
11519af6
MD
825 /*
826 * iter_prev points to the non-removed node prior to the
827 * insert location.
11519af6 828 */
04db56f8 829 iter_prev = bucket;
1ee8f000 830 /* We can always skip the bucket node initially */
04db56f8
LJ
831 iter = rcu_dereference(iter_prev->next);
832 assert(iter_prev->reverse_hash <= node->reverse_hash);
abc490a1 833 for (;;) {
8ed51e04 834 if (caa_unlikely(is_end(iter)))
273399de 835 goto insert;
04db56f8 836 if (caa_likely(clear_flag(iter)->reverse_hash > node->reverse_hash))
273399de 837 goto insert;
238cc06e 838
1ee8f000
LJ
839 /* bucket node is the first node of the identical-hash-value chain */
840 if (bucket_flag && clear_flag(iter)->reverse_hash == node->reverse_hash)
194fdbd1 841 goto insert;
238cc06e 842
04db56f8 843 next = rcu_dereference(clear_flag(iter)->next);
8ed51e04 844 if (caa_unlikely(is_removed(next)))
9dba85be 845 goto gc_node;
238cc06e
LJ
846
847 /* uniquely add */
83beee94 848 if (unique_ret
1ee8f000 849 && !is_bucket(next)
04db56f8 850 && clear_flag(iter)->reverse_hash == node->reverse_hash) {
238cc06e
LJ
851 struct cds_lfht_iter d_iter = { .node = node, .next = iter, };
852
853 /*
854 * uniquely adding inserts the node as the first
855 * node of the identical-hash-value node chain.
856 *
857 * This semantic ensures no duplicated keys
858 * should ever be observable in the table
859 * (including observe one node by one node
860 * by forward iterations)
861 */
04db56f8 862 cds_lfht_next_duplicate(ht, match, key, &d_iter);
238cc06e
LJ
863 if (!d_iter.node)
864 goto insert;
865
866 *unique_ret = d_iter;
83beee94 867 return;
48ed1c18 868 }
238cc06e 869
11519af6 870 /* Only account for identical reverse hash once */
04db56f8 871 if (iter_prev->reverse_hash != clear_flag(iter)->reverse_hash
1ee8f000 872 && !is_bucket(next))
4105056a 873 check_resize(ht, size, ++chain_len);
11519af6 874 iter_prev = clear_flag(iter);
273399de 875 iter = next;
abc490a1 876 }
48ed1c18 877
273399de 878 insert:
7ec59d3b 879 assert(node != clear_flag(iter));
11519af6 880 assert(!is_removed(iter_prev));
c90201ac 881 assert(!is_removed(iter));
f000907d 882 assert(iter_prev != node);
1ee8f000 883 if (!bucket_flag)
04db56f8 884 node->next = clear_flag(iter);
f9c80341 885 else
1ee8f000
LJ
886 node->next = flag_bucket(clear_flag(iter));
887 if (is_bucket(iter))
888 new_node = flag_bucket(node);
f5596c94
MD
889 else
890 new_node = node;
04db56f8 891 if (uatomic_cmpxchg(&iter_prev->next, iter,
48ed1c18 892 new_node) != iter) {
273399de 893 continue; /* retry */
48ed1c18 894 } else {
83beee94 895 return_node = node;
960c9e4f 896 goto end;
48ed1c18
MD
897 }
898
9dba85be
MD
899 gc_node:
900 assert(!is_removed(iter));
1ee8f000
LJ
901 if (is_bucket(iter))
902 new_next = flag_bucket(clear_flag(next));
f5596c94
MD
903 else
904 new_next = clear_flag(next);
04db56f8 905 (void) uatomic_cmpxchg(&iter_prev->next, iter, new_next);
273399de 906 /* retry */
464a1ec9 907 }
9357c415 908end:
83beee94
MD
909 if (unique_ret) {
910 unique_ret->node = return_node;
911 /* unique_ret->next left unset, never used. */
912 }
abc490a1 913}
464a1ec9 914
abc490a1 915static
860d07e8 916int _cds_lfht_del(struct cds_lfht *ht, unsigned long size,
4105056a 917 struct cds_lfht_node *node,
1ee8f000 918 int bucket_removal)
abc490a1 919{
04db56f8 920 struct cds_lfht_node *bucket, *next, *old;
5e28c532 921
9357c415 922 if (!node) /* Return -ENOENT if asked to delete NULL node */
743f9143 923 return -ENOENT;
9357c415 924
7ec59d3b 925 /* logically delete the node */
1ee8f000 926 assert(!is_bucket(node));
c90201ac 927 assert(!is_removed(node));
04db56f8 928 old = rcu_dereference(node->next);
7ec59d3b 929 do {
48ed1c18
MD
930 struct cds_lfht_node *new_next;
931
7ec59d3b 932 next = old;
8ed51e04 933 if (caa_unlikely(is_removed(next)))
743f9143 934 return -ENOENT;
1ee8f000
LJ
935 if (bucket_removal)
936 assert(is_bucket(next));
1475579c 937 else
1ee8f000 938 assert(!is_bucket(next));
48ed1c18 939 new_next = flag_removed(next);
04db56f8 940 old = uatomic_cmpxchg(&node->next, next, new_next);
7ec59d3b 941 } while (old != next);
7ec59d3b 942 /* We performed the (logical) deletion. */
7ec59d3b
MD
943
944 /*
945 * Ensure that the node is not visible to readers anymore: lookup for
273399de
MD
946 * the node, and remove it (along with any other logically removed node)
947 * if found.
11519af6 948 */
04db56f8
LJ
949 bucket = lookup_bucket(ht, size, bit_reverse_ulong(node->reverse_hash));
950 _cds_lfht_gc_bucket(bucket, node);
743f9143 951
04db56f8 952 assert(is_removed(rcu_dereference(node->next)));
743f9143 953 return 0;
abc490a1 954}
2ed95849 955
b7d619b0
MD
956static
957void *partition_resize_thread(void *arg)
958{
959 struct partition_resize_work *work = arg;
960
7b17c13e 961 work->ht->flavor->register_thread();
b7d619b0 962 work->fct(work->ht, work->i, work->start, work->len);
7b17c13e 963 work->ht->flavor->unregister_thread();
b7d619b0
MD
964 return NULL;
965}
966
967static
968void partition_resize_helper(struct cds_lfht *ht, unsigned long i,
969 unsigned long len,
970 void (*fct)(struct cds_lfht *ht, unsigned long i,
971 unsigned long start, unsigned long len))
972{
973 unsigned long partition_len;
974 struct partition_resize_work *work;
6083a889
MD
975 int thread, ret;
976 unsigned long nr_threads;
b7d619b0 977
6083a889
MD
978 /*
979 * Note: nr_cpus_mask + 1 is always power of 2.
980 * We spawn just the number of threads we need to satisfy the minimum
981 * partition size, up to the number of CPUs in the system.
982 */
91452a6a
MD
983 if (nr_cpus_mask > 0) {
984 nr_threads = min(nr_cpus_mask + 1,
985 len >> MIN_PARTITION_PER_THREAD_ORDER);
986 } else {
987 nr_threads = 1;
988 }
6083a889
MD
989 partition_len = len >> get_count_order_ulong(nr_threads);
990 work = calloc(nr_threads, sizeof(*work));
b7d619b0 991 assert(work);
6083a889
MD
992 for (thread = 0; thread < nr_threads; thread++) {
993 work[thread].ht = ht;
994 work[thread].i = i;
995 work[thread].len = partition_len;
996 work[thread].start = thread * partition_len;
997 work[thread].fct = fct;
1af6e26e 998 ret = pthread_create(&(work[thread].thread_id), ht->resize_attr,
6083a889 999 partition_resize_thread, &work[thread]);
b7d619b0
MD
1000 assert(!ret);
1001 }
6083a889 1002 for (thread = 0; thread < nr_threads; thread++) {
1af6e26e 1003 ret = pthread_join(work[thread].thread_id, NULL);
b7d619b0
MD
1004 assert(!ret);
1005 }
1006 free(work);
b7d619b0
MD
1007}
1008
e8de508e
MD
1009/*
1010 * Holding RCU read lock to protect _cds_lfht_add against memory
1011 * reclaim that could be performed by other call_rcu worker threads (ABA
1012 * problem).
9ee0fc9a 1013 *
b7d619b0 1014 * When we reach a certain length, we can split this population phase over
9ee0fc9a
MD
1015 * many worker threads, based on the number of CPUs available in the system.
1016 * This should therefore take care of not having the expand lagging behind too
1017 * many concurrent insertion threads by using the scheduler's ability to
1ee8f000 1018 * schedule bucket node population fairly with insertions.
e8de508e 1019 */
4105056a 1020static
b7d619b0
MD
1021void init_table_populate_partition(struct cds_lfht *ht, unsigned long i,
1022 unsigned long start, unsigned long len)
4105056a 1023{
9d72a73f 1024 unsigned long j, size = 1UL << (i - 1);
4105056a 1025
d0d8f9aa 1026 assert(i > MIN_TABLE_ORDER);
7b17c13e 1027 ht->flavor->read_lock();
9d72a73f
LJ
1028 for (j = size + start; j < size + start + len; j++) {
1029 struct cds_lfht_node *new_node = bucket_at(ht, j);
1030
1031 assert(j >= size && j < (size << 1));
1032 dbg_printf("init populate: order %lu index %lu hash %lu\n",
1033 i, j, j);
1034 new_node->reverse_hash = bit_reverse_ulong(j);
1035 _cds_lfht_add(ht, NULL, NULL, size, new_node, NULL, 1);
4105056a 1036 }
7b17c13e 1037 ht->flavor->read_unlock();
b7d619b0
MD
1038}
1039
1040static
1041void init_table_populate(struct cds_lfht *ht, unsigned long i,
1042 unsigned long len)
1043{
1044 assert(nr_cpus_mask != -1);
6083a889 1045 if (nr_cpus_mask < 0 || len < 2 * MIN_PARTITION_PER_THREAD) {
7b17c13e 1046 ht->flavor->thread_online();
b7d619b0 1047 init_table_populate_partition(ht, i, 0, len);
7b17c13e 1048 ht->flavor->thread_offline();
b7d619b0
MD
1049 return;
1050 }
1051 partition_resize_helper(ht, i, len, init_table_populate_partition);
4105056a
MD
1052}
1053
abc490a1 1054static
4105056a 1055void init_table(struct cds_lfht *ht,
93d46c39 1056 unsigned long first_order, unsigned long last_order)
24365af7 1057{
93d46c39 1058 unsigned long i;
24365af7 1059
93d46c39
LJ
1060 dbg_printf("init table: first_order %lu last_order %lu\n",
1061 first_order, last_order);
d0d8f9aa 1062 assert(first_order > MIN_TABLE_ORDER);
93d46c39 1063 for (i = first_order; i <= last_order; i++) {
4105056a 1064 unsigned long len;
24365af7 1065
4f6e90b7 1066 len = 1UL << (i - 1);
f0c29ed7 1067 dbg_printf("init order %lu len: %lu\n", i, len);
4d676753
MD
1068
1069 /* Stop expand if the resize target changes under us */
7b3893e4 1070 if (CMM_LOAD_SHARED(ht->resize_target) < (1UL << i))
4d676753
MD
1071 break;
1072
48f1b16d 1073 cds_lfht_alloc_bucket_table(ht, i);
4105056a 1074
4105056a 1075 /*
1ee8f000
LJ
1076 * Set all bucket nodes reverse hash values for a level and
1077 * link all bucket nodes into the table.
4105056a 1078 */
dc1da8f6 1079 init_table_populate(ht, i, len);
4105056a 1080
f9c80341
MD
1081 /*
1082 * Update table size.
1083 */
1084 cmm_smp_wmb(); /* populate data before RCU size */
7b3893e4 1085 CMM_STORE_SHARED(ht->size, 1UL << i);
f9c80341 1086
4f6e90b7 1087 dbg_printf("init new size: %lu\n", 1UL << i);
4105056a
MD
1088 if (CMM_LOAD_SHARED(ht->in_progress_destroy))
1089 break;
1090 }
1091}
1092
e8de508e
MD
1093/*
1094 * Holding RCU read lock to protect _cds_lfht_remove against memory
1095 * reclaim that could be performed by other call_rcu worker threads (ABA
1096 * problem).
1097 * For a single level, we logically remove and garbage collect each node.
1098 *
1099 * As a design choice, we perform logical removal and garbage collection on a
1100 * node-per-node basis to simplify this algorithm. We also assume keeping good
1101 * cache locality of the operation would overweight possible performance gain
1102 * that could be achieved by batching garbage collection for multiple levels.
1103 * However, this would have to be justified by benchmarks.
1104 *
1105 * Concurrent removal and add operations are helping us perform garbage
1106 * collection of logically removed nodes. We guarantee that all logically
1107 * removed nodes have been garbage-collected (unlinked) before call_rcu is
1ee8f000 1108 * invoked to free a hole level of bucket nodes (after a grace period).
e8de508e
MD
1109 *
1110 * Logical removal and garbage collection can therefore be done in batch or on a
1111 * node-per-node basis, as long as the guarantee above holds.
9ee0fc9a 1112 *
b7d619b0
MD
1113 * When we reach a certain length, we can split this removal over many worker
1114 * threads, based on the number of CPUs available in the system. This should
1115 * take care of not letting resize process lag behind too many concurrent
9ee0fc9a 1116 * updater threads actively inserting into the hash table.
e8de508e 1117 */
4105056a 1118static
b7d619b0
MD
1119void remove_table_partition(struct cds_lfht *ht, unsigned long i,
1120 unsigned long start, unsigned long len)
4105056a 1121{
9d72a73f 1122 unsigned long j, size = 1UL << (i - 1);
4105056a 1123
d0d8f9aa 1124 assert(i > MIN_TABLE_ORDER);
7b17c13e 1125 ht->flavor->read_lock();
9d72a73f
LJ
1126 for (j = size + start; j < size + start + len; j++) {
1127 struct cds_lfht_node *fini_node = bucket_at(ht, j);
1128
1129 assert(j >= size && j < (size << 1));
1130 dbg_printf("remove entry: order %lu index %lu hash %lu\n",
1131 i, j, j);
1132 fini_node->reverse_hash = bit_reverse_ulong(j);
1133 (void) _cds_lfht_del(ht, size, fini_node, 1);
abc490a1 1134 }
7b17c13e 1135 ht->flavor->read_unlock();
b7d619b0
MD
1136}
1137
1138static
1139void remove_table(struct cds_lfht *ht, unsigned long i, unsigned long len)
1140{
1141
1142 assert(nr_cpus_mask != -1);
6083a889 1143 if (nr_cpus_mask < 0 || len < 2 * MIN_PARTITION_PER_THREAD) {
7b17c13e 1144 ht->flavor->thread_online();
b7d619b0 1145 remove_table_partition(ht, i, 0, len);
7b17c13e 1146 ht->flavor->thread_offline();
b7d619b0
MD
1147 return;
1148 }
1149 partition_resize_helper(ht, i, len, remove_table_partition);
2ed95849
MD
1150}
1151
61adb337
MD
1152/*
1153 * fini_table() is never called for first_order == 0, which is why
1154 * free_by_rcu_order == 0 can be used as criterion to know if free must
1155 * be called.
1156 */
1475579c 1157static
4105056a 1158void fini_table(struct cds_lfht *ht,
93d46c39 1159 unsigned long first_order, unsigned long last_order)
1475579c 1160{
93d46c39 1161 long i;
48f1b16d 1162 unsigned long free_by_rcu_order = 0;
1475579c 1163
93d46c39
LJ
1164 dbg_printf("fini table: first_order %lu last_order %lu\n",
1165 first_order, last_order);
d0d8f9aa 1166 assert(first_order > MIN_TABLE_ORDER);
93d46c39 1167 for (i = last_order; i >= first_order; i--) {
4105056a 1168 unsigned long len;
1475579c 1169
4f6e90b7 1170 len = 1UL << (i - 1);
1475579c 1171 dbg_printf("fini order %lu len: %lu\n", i, len);
4105056a 1172
4d676753 1173 /* Stop shrink if the resize target changes under us */
7b3893e4 1174 if (CMM_LOAD_SHARED(ht->resize_target) > (1UL << (i - 1)))
4d676753
MD
1175 break;
1176
1177 cmm_smp_wmb(); /* populate data before RCU size */
7b3893e4 1178 CMM_STORE_SHARED(ht->size, 1UL << (i - 1));
4d676753
MD
1179
1180 /*
1181 * We need to wait for all add operations to reach Q.S. (and
1182 * thus use the new table for lookups) before we can start
1ee8f000 1183 * releasing the old bucket nodes. Otherwise their lookup will
4d676753
MD
1184 * return a logically removed node as insert position.
1185 */
7b17c13e 1186 ht->flavor->update_synchronize_rcu();
48f1b16d
LJ
1187 if (free_by_rcu_order)
1188 cds_lfht_free_bucket_table(ht, free_by_rcu_order);
4d676753 1189
21263e21 1190 /*
1ee8f000
LJ
1191 * Set "removed" flag in bucket nodes about to be removed.
1192 * Unlink all now-logically-removed bucket node pointers.
4105056a
MD
1193 * Concurrent add/remove operation are helping us doing
1194 * the gc.
21263e21 1195 */
4105056a
MD
1196 remove_table(ht, i, len);
1197
48f1b16d 1198 free_by_rcu_order = i;
4105056a
MD
1199
1200 dbg_printf("fini new size: %lu\n", 1UL << i);
1475579c
MD
1201 if (CMM_LOAD_SHARED(ht->in_progress_destroy))
1202 break;
1203 }
0d14ceb2 1204
48f1b16d 1205 if (free_by_rcu_order) {
7b17c13e 1206 ht->flavor->update_synchronize_rcu();
48f1b16d 1207 cds_lfht_free_bucket_table(ht, free_by_rcu_order);
0d14ceb2 1208 }
1475579c
MD
1209}
1210
ff0d69de 1211static
1ee8f000 1212void cds_lfht_create_bucket(struct cds_lfht *ht, unsigned long size)
ff0d69de 1213{
04db56f8 1214 struct cds_lfht_node *prev, *node;
9d72a73f 1215 unsigned long order, len, i;
ff0d69de 1216
48f1b16d 1217 cds_lfht_alloc_bucket_table(ht, 0);
ff0d69de 1218
9d72a73f
LJ
1219 dbg_printf("create bucket: order 0 index 0 hash 0\n");
1220 node = bucket_at(ht, 0);
1221 node->next = flag_bucket(get_end());
1222 node->reverse_hash = 0;
ff0d69de
LJ
1223
1224 for (order = 1; order < get_count_order_ulong(size) + 1; order++) {
1225 len = 1UL << (order - 1);
48f1b16d 1226 cds_lfht_alloc_bucket_table(ht, order);
ff0d69de 1227
9d72a73f
LJ
1228 for (i = 0; i < len; i++) {
1229 /*
1230 * Now, we are trying to init the node with the
1231 * hash=(len+i) (which is also a bucket with the
1232 * index=(len+i)) and insert it into the hash table,
1233 * so this node has to be inserted after the bucket
1234 * with the index=(len+i)&(len-1)=i. And because there
1235 * is no other non-bucket node nor bucket node with
1236 * larger index/hash inserted, so the bucket node
1237 * being inserted should be inserted directly linked
1238 * after the bucket node with index=i.
1239 */
1240 prev = bucket_at(ht, i);
1241 node = bucket_at(ht, len + i);
ff0d69de 1242
1ee8f000 1243 dbg_printf("create bucket: order %lu index %lu hash %lu\n",
9d72a73f
LJ
1244 order, len + i, len + i);
1245 node->reverse_hash = bit_reverse_ulong(len + i);
1246
1247 /* insert after prev */
1248 assert(is_bucket(prev->next));
ff0d69de 1249 node->next = prev->next;
1ee8f000 1250 prev->next = flag_bucket(node);
ff0d69de
LJ
1251 }
1252 }
1253}
1254
0422d92c 1255struct cds_lfht *_cds_lfht_new(unsigned long init_size,
0722081a 1256 unsigned long min_nr_alloc_buckets,
747d725c 1257 unsigned long max_nr_buckets,
b8af5011 1258 int flags,
0b6aa001 1259 const struct cds_lfht_mm_type *mm,
7b17c13e 1260 const struct rcu_flavor_struct *flavor,
b7d619b0 1261 pthread_attr_t *attr)
abc490a1 1262{
14044b37 1263 struct cds_lfht *ht;
24365af7 1264 unsigned long order;
abc490a1 1265
0722081a
LJ
1266 /* min_nr_alloc_buckets must be power of two */
1267 if (!min_nr_alloc_buckets || (min_nr_alloc_buckets & (min_nr_alloc_buckets - 1)))
5488222b 1268 return NULL;
747d725c 1269
8129be4e 1270 /* init_size must be power of two */
5488222b 1271 if (!init_size || (init_size & (init_size - 1)))
8129be4e 1272 return NULL;
747d725c 1273
0b6aa001
LJ
1274 /* max_nr_buckets == 0 for order based mm means infinite */
1275 if (mm == &cds_lfht_mm_order && !max_nr_buckets)
747d725c
LJ
1276 max_nr_buckets = 1UL << (MAX_TABLE_ORDER - 1);
1277
1278 /* max_nr_buckets must be power of two */
1279 if (!max_nr_buckets || (max_nr_buckets & (max_nr_buckets - 1)))
1280 return NULL;
1281
0722081a 1282 min_nr_alloc_buckets = max(min_nr_alloc_buckets, MIN_TABLE_SIZE);
d0d8f9aa 1283 init_size = max(init_size, MIN_TABLE_SIZE);
747d725c
LJ
1284 max_nr_buckets = max(max_nr_buckets, min_nr_alloc_buckets);
1285 init_size = min(init_size, max_nr_buckets);
0b6aa001
LJ
1286
1287 ht = mm->alloc_cds_lfht(min_nr_alloc_buckets, max_nr_buckets);
b7d619b0 1288 assert(ht);
0b6aa001
LJ
1289 assert(ht->mm == mm);
1290 assert(ht->bucket_at == mm->bucket_at);
1291
b5d6b20f 1292 ht->flags = flags;
7b17c13e 1293 ht->flavor = flavor;
b7d619b0 1294 ht->resize_attr = attr;
5afadd12 1295 alloc_split_items_count(ht);
abc490a1
MD
1296 /* this mutex should not nest in read-side C.S. */
1297 pthread_mutex_init(&ht->resize_mutex, NULL);
5488222b 1298 order = get_count_order_ulong(init_size);
7b3893e4 1299 ht->resize_target = 1UL << order;
1ee8f000 1300 cds_lfht_create_bucket(ht, 1UL << order);
7b3893e4 1301 ht->size = 1UL << order;
abc490a1
MD
1302 return ht;
1303}
1304
6f554439 1305void cds_lfht_lookup(struct cds_lfht *ht, unsigned long hash,
996ff57c 1306 cds_lfht_match_fct match, const void *key,
6f554439 1307 struct cds_lfht_iter *iter)
2ed95849 1308{
04db56f8 1309 struct cds_lfht_node *node, *next, *bucket;
0422d92c 1310 unsigned long reverse_hash, size;
2ed95849 1311
abc490a1 1312 reverse_hash = bit_reverse_ulong(hash);
464a1ec9 1313
7b3893e4 1314 size = rcu_dereference(ht->size);
04db56f8 1315 bucket = lookup_bucket(ht, size, hash);
1ee8f000 1316 /* We can always skip the bucket node initially */
04db56f8 1317 node = rcu_dereference(bucket->next);
bb7b2f26 1318 node = clear_flag(node);
2ed95849 1319 for (;;) {
8ed51e04 1320 if (caa_unlikely(is_end(node))) {
96ad1112 1321 node = next = NULL;
abc490a1 1322 break;
bb7b2f26 1323 }
04db56f8 1324 if (caa_unlikely(node->reverse_hash > reverse_hash)) {
96ad1112 1325 node = next = NULL;
abc490a1 1326 break;
2ed95849 1327 }
04db56f8 1328 next = rcu_dereference(node->next);
7f52427b 1329 assert(node == clear_flag(node));
8ed51e04 1330 if (caa_likely(!is_removed(next))
1ee8f000 1331 && !is_bucket(next)
04db56f8 1332 && node->reverse_hash == reverse_hash
0422d92c 1333 && caa_likely(match(node, key))) {
273399de 1334 break;
2ed95849 1335 }
1b81fe1a 1336 node = clear_flag(next);
2ed95849 1337 }
1ee8f000 1338 assert(!node || !is_bucket(rcu_dereference(node->next)));
adc0de68
MD
1339 iter->node = node;
1340 iter->next = next;
abc490a1 1341}
e0ba718a 1342
0422d92c 1343void cds_lfht_next_duplicate(struct cds_lfht *ht, cds_lfht_match_fct match,
996ff57c 1344 const void *key, struct cds_lfht_iter *iter)
a481e5ff 1345{
adc0de68 1346 struct cds_lfht_node *node, *next;
a481e5ff 1347 unsigned long reverse_hash;
a481e5ff 1348
adc0de68 1349 node = iter->node;
04db56f8 1350 reverse_hash = node->reverse_hash;
adc0de68 1351 next = iter->next;
a481e5ff
MD
1352 node = clear_flag(next);
1353
1354 for (;;) {
8ed51e04 1355 if (caa_unlikely(is_end(node))) {
96ad1112 1356 node = next = NULL;
a481e5ff 1357 break;
bb7b2f26 1358 }
04db56f8 1359 if (caa_unlikely(node->reverse_hash > reverse_hash)) {
96ad1112 1360 node = next = NULL;
a481e5ff
MD
1361 break;
1362 }
04db56f8 1363 next = rcu_dereference(node->next);
8ed51e04 1364 if (caa_likely(!is_removed(next))
1ee8f000 1365 && !is_bucket(next)
04db56f8 1366 && caa_likely(match(node, key))) {
a481e5ff
MD
1367 break;
1368 }
1369 node = clear_flag(next);
1370 }
1ee8f000 1371 assert(!node || !is_bucket(rcu_dereference(node->next)));
adc0de68
MD
1372 iter->node = node;
1373 iter->next = next;
a481e5ff
MD
1374}
1375
4e9b9fbf
MD
1376void cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_iter *iter)
1377{
1378 struct cds_lfht_node *node, *next;
1379
853395e1 1380 node = clear_flag(iter->next);
4e9b9fbf 1381 for (;;) {
8ed51e04 1382 if (caa_unlikely(is_end(node))) {
4e9b9fbf
MD
1383 node = next = NULL;
1384 break;
1385 }
04db56f8 1386 next = rcu_dereference(node->next);
8ed51e04 1387 if (caa_likely(!is_removed(next))
1ee8f000 1388 && !is_bucket(next)) {
4e9b9fbf
MD
1389 break;
1390 }
1391 node = clear_flag(next);
1392 }
1ee8f000 1393 assert(!node || !is_bucket(rcu_dereference(node->next)));
4e9b9fbf
MD
1394 iter->node = node;
1395 iter->next = next;
1396}
1397
1398void cds_lfht_first(struct cds_lfht *ht, struct cds_lfht_iter *iter)
1399{
4e9b9fbf 1400 /*
1ee8f000 1401 * Get next after first bucket node. The first bucket node is the
4e9b9fbf
MD
1402 * first node of the linked list.
1403 */
9d72a73f 1404 iter->next = bucket_at(ht, 0)->next;
4e9b9fbf
MD
1405 cds_lfht_next(ht, iter);
1406}
1407
0422d92c
MD
1408void cds_lfht_add(struct cds_lfht *ht, unsigned long hash,
1409 struct cds_lfht_node *node)
abc490a1 1410{
0422d92c 1411 unsigned long size;
ab7d5fc6 1412
04db56f8 1413 node->reverse_hash = bit_reverse_ulong((unsigned long) hash);
7b3893e4 1414 size = rcu_dereference(ht->size);
04db56f8 1415 _cds_lfht_add(ht, NULL, NULL, size, node, NULL, 0);
14360f1c 1416 ht_count_add(ht, size, hash);
3eca1b8c
MD
1417}
1418
14044b37 1419struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht,
6f554439 1420 unsigned long hash,
0422d92c 1421 cds_lfht_match_fct match,
996ff57c 1422 const void *key,
48ed1c18 1423 struct cds_lfht_node *node)
3eca1b8c 1424{
0422d92c 1425 unsigned long size;
83beee94 1426 struct cds_lfht_iter iter;
3eca1b8c 1427
04db56f8 1428 node->reverse_hash = bit_reverse_ulong((unsigned long) hash);
7b3893e4 1429 size = rcu_dereference(ht->size);
04db56f8 1430 _cds_lfht_add(ht, match, key, size, node, &iter, 0);
83beee94 1431 if (iter.node == node)
14360f1c 1432 ht_count_add(ht, size, hash);
83beee94 1433 return iter.node;
2ed95849
MD
1434}
1435
9357c415 1436struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht,
6f554439 1437 unsigned long hash,
0422d92c 1438 cds_lfht_match_fct match,
996ff57c 1439 const void *key,
48ed1c18
MD
1440 struct cds_lfht_node *node)
1441{
0422d92c 1442 unsigned long size;
83beee94 1443 struct cds_lfht_iter iter;
48ed1c18 1444
04db56f8 1445 node->reverse_hash = bit_reverse_ulong((unsigned long) hash);
7b3893e4 1446 size = rcu_dereference(ht->size);
83beee94 1447 for (;;) {
04db56f8 1448 _cds_lfht_add(ht, match, key, size, node, &iter, 0);
83beee94 1449 if (iter.node == node) {
14360f1c 1450 ht_count_add(ht, size, hash);
83beee94
MD
1451 return NULL;
1452 }
1453
1454 if (!_cds_lfht_replace(ht, size, iter.node, iter.next, node))
1455 return iter.node;
1456 }
48ed1c18
MD
1457}
1458
9357c415
MD
1459int cds_lfht_replace(struct cds_lfht *ht, struct cds_lfht_iter *old_iter,
1460 struct cds_lfht_node *new_node)
1461{
1462 unsigned long size;
1463
7b3893e4 1464 size = rcu_dereference(ht->size);
9357c415
MD
1465 return _cds_lfht_replace(ht, size, old_iter->node, old_iter->next,
1466 new_node);
1467}
1468
1469int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_iter *iter)
2ed95849 1470{
14360f1c 1471 unsigned long size, hash;
df44348d 1472 int ret;
abc490a1 1473
7b3893e4 1474 size = rcu_dereference(ht->size);
9357c415 1475 ret = _cds_lfht_del(ht, size, iter->node, 0);
14360f1c 1476 if (!ret) {
04db56f8 1477 hash = bit_reverse_ulong(iter->node->reverse_hash);
14360f1c
LJ
1478 ht_count_del(ht, size, hash);
1479 }
df44348d 1480 return ret;
2ed95849 1481}
ab7d5fc6 1482
abc490a1 1483static
1ee8f000 1484int cds_lfht_delete_bucket(struct cds_lfht *ht)
674f7a69 1485{
14044b37 1486 struct cds_lfht_node *node;
4105056a 1487 unsigned long order, i, size;
674f7a69 1488
abc490a1 1489 /* Check that the table is empty */
9d72a73f 1490 node = bucket_at(ht, 0);
abc490a1 1491 do {
04db56f8 1492 node = clear_flag(node)->next;
1ee8f000 1493 if (!is_bucket(node))
abc490a1 1494 return -EPERM;
273399de 1495 assert(!is_removed(node));
bb7b2f26 1496 } while (!is_end(node));
4105056a
MD
1497 /*
1498 * size accessed without rcu_dereference because hash table is
1499 * being destroyed.
1500 */
7b3893e4 1501 size = ht->size;
1ee8f000 1502 /* Internal sanity check: all nodes left should be bucket */
48f1b16d
LJ
1503 for (i = 0; i < size; i++) {
1504 node = bucket_at(ht, i);
1505 dbg_printf("delete bucket: index %lu expected hash %lu hash %lu\n",
1506 i, i, bit_reverse_ulong(node->reverse_hash));
1507 assert(is_bucket(node->next));
1508 }
24365af7 1509
48f1b16d
LJ
1510 for (order = get_count_order_ulong(size); (long)order >= 0; order--)
1511 cds_lfht_free_bucket_table(ht, order);
5488222b 1512
abc490a1 1513 return 0;
674f7a69
MD
1514}
1515
1516/*
1517 * Should only be called when no more concurrent readers nor writers can
1518 * possibly access the table.
1519 */
b7d619b0 1520int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr)
674f7a69 1521{
5e28c532
MD
1522 int ret;
1523
848d4088 1524 /* Wait for in-flight resize operations to complete */
24953e08
MD
1525 _CMM_STORE_SHARED(ht->in_progress_destroy, 1);
1526 cmm_smp_mb(); /* Store destroy before load resize */
848d4088
MD
1527 while (uatomic_read(&ht->in_progress_resize))
1528 poll(NULL, 0, 100); /* wait for 100ms */
1ee8f000 1529 ret = cds_lfht_delete_bucket(ht);
abc490a1
MD
1530 if (ret)
1531 return ret;
5afadd12 1532 free_split_items_count(ht);
b7d619b0
MD
1533 if (attr)
1534 *attr = ht->resize_attr;
98808fb1 1535 poison_free(ht);
5e28c532 1536 return ret;
674f7a69
MD
1537}
1538
14044b37 1539void cds_lfht_count_nodes(struct cds_lfht *ht,
d933dd0e 1540 long *approx_before,
273399de 1541 unsigned long *count,
973e5e1b 1542 unsigned long *removed,
d933dd0e 1543 long *approx_after)
273399de 1544{
14044b37 1545 struct cds_lfht_node *node, *next;
1ee8f000 1546 unsigned long nr_bucket = 0;
273399de 1547
7ed7682f 1548 *approx_before = 0;
5afadd12 1549 if (ht->split_count) {
973e5e1b
MD
1550 int i;
1551
4c42f1b8
LJ
1552 for (i = 0; i < split_count_mask + 1; i++) {
1553 *approx_before += uatomic_read(&ht->split_count[i].add);
1554 *approx_before -= uatomic_read(&ht->split_count[i].del);
973e5e1b
MD
1555 }
1556 }
1557
273399de
MD
1558 *count = 0;
1559 *removed = 0;
1560
1ee8f000 1561 /* Count non-bucket nodes in the table */
9d72a73f 1562 node = bucket_at(ht, 0);
273399de 1563 do {
04db56f8 1564 next = rcu_dereference(node->next);
b198f0fd 1565 if (is_removed(next)) {
1ee8f000 1566 if (!is_bucket(next))
973e5e1b
MD
1567 (*removed)++;
1568 else
1ee8f000
LJ
1569 (nr_bucket)++;
1570 } else if (!is_bucket(next))
273399de 1571 (*count)++;
24365af7 1572 else
1ee8f000 1573 (nr_bucket)++;
273399de 1574 node = clear_flag(next);
bb7b2f26 1575 } while (!is_end(node));
1ee8f000 1576 dbg_printf("number of bucket nodes: %lu\n", nr_bucket);
7ed7682f 1577 *approx_after = 0;
5afadd12 1578 if (ht->split_count) {
973e5e1b
MD
1579 int i;
1580
4c42f1b8
LJ
1581 for (i = 0; i < split_count_mask + 1; i++) {
1582 *approx_after += uatomic_read(&ht->split_count[i].add);
1583 *approx_after -= uatomic_read(&ht->split_count[i].del);
973e5e1b
MD
1584 }
1585 }
273399de
MD
1586}
1587
1475579c 1588/* called with resize mutex held */
abc490a1 1589static
4105056a 1590void _do_cds_lfht_grow(struct cds_lfht *ht,
1475579c 1591 unsigned long old_size, unsigned long new_size)
abc490a1 1592{
1475579c 1593 unsigned long old_order, new_order;
1475579c 1594
93d46c39
LJ
1595 old_order = get_count_order_ulong(old_size);
1596 new_order = get_count_order_ulong(new_size);
1a401918
LJ
1597 dbg_printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n",
1598 old_size, old_order, new_size, new_order);
1475579c 1599 assert(new_size > old_size);
93d46c39 1600 init_table(ht, old_order + 1, new_order);
abc490a1
MD
1601}
1602
1603/* called with resize mutex held */
1604static
4105056a 1605void _do_cds_lfht_shrink(struct cds_lfht *ht,
1475579c 1606 unsigned long old_size, unsigned long new_size)
464a1ec9 1607{
1475579c 1608 unsigned long old_order, new_order;
464a1ec9 1609
d0d8f9aa 1610 new_size = max(new_size, MIN_TABLE_SIZE);
93d46c39
LJ
1611 old_order = get_count_order_ulong(old_size);
1612 new_order = get_count_order_ulong(new_size);
1a401918
LJ
1613 dbg_printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n",
1614 old_size, old_order, new_size, new_order);
1475579c 1615 assert(new_size < old_size);
1475579c 1616
1ee8f000 1617 /* Remove and unlink all bucket nodes to remove. */
93d46c39 1618 fini_table(ht, new_order + 1, old_order);
464a1ec9
MD
1619}
1620
1475579c
MD
1621
1622/* called with resize mutex held */
1623static
1624void _do_cds_lfht_resize(struct cds_lfht *ht)
1625{
1626 unsigned long new_size, old_size;
4105056a
MD
1627
1628 /*
1629 * Resize table, re-do if the target size has changed under us.
1630 */
1631 do {
d2be3620
MD
1632 assert(uatomic_read(&ht->in_progress_resize));
1633 if (CMM_LOAD_SHARED(ht->in_progress_destroy))
1634 break;
7b3893e4
LJ
1635 ht->resize_initiated = 1;
1636 old_size = ht->size;
1637 new_size = CMM_LOAD_SHARED(ht->resize_target);
4105056a
MD
1638 if (old_size < new_size)
1639 _do_cds_lfht_grow(ht, old_size, new_size);
1640 else if (old_size > new_size)
1641 _do_cds_lfht_shrink(ht, old_size, new_size);
7b3893e4 1642 ht->resize_initiated = 0;
4105056a
MD
1643 /* write resize_initiated before read resize_target */
1644 cmm_smp_mb();
7b3893e4 1645 } while (ht->size != CMM_LOAD_SHARED(ht->resize_target));
1475579c
MD
1646}
1647
abc490a1 1648static
ab65b890 1649unsigned long resize_target_grow(struct cds_lfht *ht, unsigned long new_size)
464a1ec9 1650{
7b3893e4 1651 return _uatomic_xchg_monotonic_increase(&ht->resize_target, new_size);
464a1ec9
MD
1652}
1653
1475579c 1654static
4105056a 1655void resize_target_update_count(struct cds_lfht *ht,
b8af5011 1656 unsigned long count)
1475579c 1657{
d0d8f9aa 1658 count = max(count, MIN_TABLE_SIZE);
747d725c 1659 count = min(count, ht->max_nr_buckets);
7b3893e4 1660 uatomic_set(&ht->resize_target, count);
1475579c
MD
1661}
1662
1663void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size)
464a1ec9 1664{
4105056a 1665 resize_target_update_count(ht, new_size);
7b3893e4 1666 CMM_STORE_SHARED(ht->resize_initiated, 1);
7b17c13e 1667 ht->flavor->thread_offline();
1475579c
MD
1668 pthread_mutex_lock(&ht->resize_mutex);
1669 _do_cds_lfht_resize(ht);
1670 pthread_mutex_unlock(&ht->resize_mutex);
7b17c13e 1671 ht->flavor->thread_online();
abc490a1 1672}
464a1ec9 1673
abc490a1
MD
1674static
1675void do_resize_cb(struct rcu_head *head)
1676{
1677 struct rcu_resize_work *work =
1678 caa_container_of(head, struct rcu_resize_work, head);
14044b37 1679 struct cds_lfht *ht = work->ht;
abc490a1 1680
7b17c13e 1681 ht->flavor->thread_offline();
abc490a1 1682 pthread_mutex_lock(&ht->resize_mutex);
14044b37 1683 _do_cds_lfht_resize(ht);
abc490a1 1684 pthread_mutex_unlock(&ht->resize_mutex);
7b17c13e 1685 ht->flavor->thread_online();
98808fb1 1686 poison_free(work);
848d4088
MD
1687 cmm_smp_mb(); /* finish resize before decrement */
1688 uatomic_dec(&ht->in_progress_resize);
464a1ec9
MD
1689}
1690
abc490a1 1691static
f1f119ee 1692void __cds_lfht_resize_lazy_launch(struct cds_lfht *ht)
ab7d5fc6 1693{
abc490a1
MD
1694 struct rcu_resize_work *work;
1695
4105056a
MD
1696 /* Store resize_target before read resize_initiated */
1697 cmm_smp_mb();
7b3893e4 1698 if (!CMM_LOAD_SHARED(ht->resize_initiated)) {
848d4088 1699 uatomic_inc(&ht->in_progress_resize);
59290e9d 1700 cmm_smp_mb(); /* increment resize count before load destroy */
ed35e6d8
MD
1701 if (CMM_LOAD_SHARED(ht->in_progress_destroy)) {
1702 uatomic_dec(&ht->in_progress_resize);
59290e9d 1703 return;
ed35e6d8 1704 }
f9830efd
MD
1705 work = malloc(sizeof(*work));
1706 work->ht = ht;
7b17c13e 1707 ht->flavor->update_call_rcu(&work->head, do_resize_cb);
7b3893e4 1708 CMM_STORE_SHARED(ht->resize_initiated, 1);
f9830efd 1709 }
ab7d5fc6 1710}
3171717f 1711
f1f119ee
LJ
1712static
1713void cds_lfht_resize_lazy_grow(struct cds_lfht *ht, unsigned long size, int growth)
1714{
1715 unsigned long target_size = size << growth;
1716
747d725c 1717 target_size = min(target_size, ht->max_nr_buckets);
f1f119ee
LJ
1718 if (resize_target_grow(ht, target_size) >= target_size)
1719 return;
1720
1721 __cds_lfht_resize_lazy_launch(ht);
1722}
1723
89bb121d
LJ
1724/*
1725 * We favor grow operations over shrink. A shrink operation never occurs
1726 * if a grow operation is queued for lazy execution. A grow operation
1727 * cancels any pending shrink lazy execution.
1728 */
3171717f 1729static
4105056a 1730void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size,
3171717f
MD
1731 unsigned long count)
1732{
b8af5011
MD
1733 if (!(ht->flags & CDS_LFHT_AUTO_RESIZE))
1734 return;
d0d8f9aa 1735 count = max(count, MIN_TABLE_SIZE);
747d725c 1736 count = min(count, ht->max_nr_buckets);
89bb121d
LJ
1737 if (count == size)
1738 return; /* Already the right size, no resize needed */
1739 if (count > size) { /* lazy grow */
1740 if (resize_target_grow(ht, count) >= count)
1741 return;
1742 } else { /* lazy shrink */
1743 for (;;) {
1744 unsigned long s;
1745
7b3893e4 1746 s = uatomic_cmpxchg(&ht->resize_target, size, count);
89bb121d
LJ
1747 if (s == size)
1748 break; /* no resize needed */
1749 if (s > size)
1750 return; /* growing is/(was just) in progress */
1751 if (s <= count)
1752 return; /* some other thread do shrink */
1753 size = s;
1754 }
1755 }
f1f119ee 1756 __cds_lfht_resize_lazy_launch(ht);
3171717f 1757}
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