1 /*
2 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_UTILITIES_CONCURRENT_HASH_TABLE_INLINE_HPP
26 #define SHARE_UTILITIES_CONCURRENT_HASH_TABLE_INLINE_HPP
27
28 #include "memory/allocation.inline.hpp"
29 #include "runtime/atomic.hpp"
30 #include "runtime/orderAccess.hpp"
31 #include "runtime/prefetch.inline.hpp"
32 #include "utilities/concurrentHashTable.hpp"
33 #include "utilities/globalCounter.inline.hpp"
34 #include "utilities/numberSeq.hpp"
35 #include "utilities/spinYield.hpp"
36
37 // 2^30 = 1G buckets
38 #define SIZE_BIG_LOG2 30
39 // 2^5 = 32 buckets
40 #define SIZE_SMALL_LOG2 5
41
42 // Number from spinYield.hpp. In some loops SpinYield would be unfair.
43 #define SPINPAUSES_PER_YIELD 8192
44
45 #ifdef ASSERT
46 #ifdef _LP64
47 // Two low bits are not usable.
48 static const void* POISON_PTR = (void*)UCONST64(0xfbadbadbadbadbac);
49 #else
50 // Two low bits are not usable.
51 static const void* POISON_PTR = (void*)0xffbadbac;
52 #endif
53 #endif
54
55 // Node
56 template <typename VALUE, typename CONFIG, MEMFLAGS F>
57 inline typename ConcurrentHashTable<VALUE, CONFIG, F>::Node*
58 ConcurrentHashTable<VALUE, CONFIG, F>::
59 Node::next() const
60 {
61 return OrderAccess::load_acquire(&_next);
62 }
63
64 // Bucket
65 template <typename VALUE, typename CONFIG, MEMFLAGS F>
66 inline typename ConcurrentHashTable<VALUE, CONFIG, F>::Node*
67 ConcurrentHashTable<VALUE, CONFIG, F>::
68 Bucket::first_raw() const
69 {
70 return OrderAccess::load_acquire(&_first);
71 }
72
73 template <typename VALUE, typename CONFIG, MEMFLAGS F>
74 inline void ConcurrentHashTable<VALUE, CONFIG, F>::
75 Bucket::release_assign_node_ptr(
76 typename ConcurrentHashTable<VALUE, CONFIG, F>::Node* const volatile * dst,
77 typename ConcurrentHashTable<VALUE, CONFIG, F>::Node* node) const
78 {
79 // Due to this assert this methods is not static.
80 assert(is_locked(), "Must be locked.");
81 Node** tmp = (Node**)dst;
82 OrderAccess::release_store(tmp, clear_set_state(node, *dst));
83 }
84
85 template <typename VALUE, typename CONFIG, MEMFLAGS F>
86 inline typename ConcurrentHashTable<VALUE, CONFIG, F>::Node*
87 ConcurrentHashTable<VALUE, CONFIG, F>::
88 Bucket::first() const
89 {
90 // We strip the states bit before returning the ptr.
91 return clear_state(OrderAccess::load_acquire(&_first));
92 }
93
94 template <typename VALUE, typename CONFIG, MEMFLAGS F>
95 inline bool ConcurrentHashTable<VALUE, CONFIG, F>::
96 Bucket::have_redirect() const
97 {
98 return is_state(first_raw(), STATE_REDIRECT_BIT);
99 }
100
101 template <typename VALUE, typename CONFIG, MEMFLAGS F>
102 inline bool ConcurrentHashTable<VALUE, CONFIG, F>::
103 Bucket::is_locked() const
104 {
105 return is_state(first_raw(), STATE_LOCK_BIT);
106 }
107
108 template <typename VALUE, typename CONFIG, MEMFLAGS F>
109 inline void ConcurrentHashTable<VALUE, CONFIG, F>::
110 Bucket::lock()
111 {
112 int i = 0;
113 // SpinYield would be unfair here
114 while (!this->trylock()) {
115 if ((++i) == SPINPAUSES_PER_YIELD) {
116 // On contemporary OS yielding will give CPU to another runnable thread if
117 // there is no CPU available.
118 os::naked_yield();
119 i = 0;
120 } else {
121 SpinPause();
122 }
123 }
124 }
125
126 template <typename VALUE, typename CONFIG, MEMFLAGS F>
127 inline void ConcurrentHashTable<VALUE, CONFIG, F>::
128 Bucket::release_assign_last_node_next(
129 typename ConcurrentHashTable<VALUE, CONFIG, F>::Node* node)
130 {
131 assert(is_locked(), "Must be locked.");
132 Node* const volatile * ret = first_ptr();
133 while (clear_state(*ret) != NULL) {
134 ret = clear_state(*ret)->next_ptr();
135 }
136 release_assign_node_ptr(ret, node);
137 }
138
139 template <typename VALUE, typename CONFIG, MEMFLAGS F>
140 inline bool ConcurrentHashTable<VALUE, CONFIG, F>::
141 Bucket::cas_first(typename ConcurrentHashTable<VALUE, CONFIG, F>::Node* node,
142 typename ConcurrentHashTable<VALUE, CONFIG, F>::Node* expect
143 )
144 {
145 if (is_locked()) {
146 return false;
147 }
148 if (Atomic::cmpxchg(node, &_first, expect) == expect) {
149 return true;
150 }
151 return false;
152 }
153
154 template <typename VALUE, typename CONFIG, MEMFLAGS F>
155 inline bool ConcurrentHashTable<VALUE, CONFIG, F>::
156 Bucket::trylock()
157 {
158 if (is_locked()) {
159 return false;
160 }
161 // We will expect a clean first pointer.
162 Node* tmp = first();
163 if (Atomic::cmpxchg(set_state(tmp, STATE_LOCK_BIT), &_first, tmp) == tmp) {
164 return true;
165 }
166 return false;
167 }
168
169 template <typename VALUE, typename CONFIG, MEMFLAGS F>
170 inline void ConcurrentHashTable<VALUE, CONFIG, F>::
171 Bucket::unlock()
172 {
173 assert(is_locked(), "Must be locked.");
174 assert(!have_redirect(),
175 "Unlocking a bucket after it has reached terminal state.");
176 OrderAccess::release_store(&_first, clear_state(first()));
177 }
178
179 template <typename VALUE, typename CONFIG, MEMFLAGS F>
180 inline void ConcurrentHashTable<VALUE, CONFIG, F>::
181 Bucket::redirect()
182 {
183 assert(is_locked(), "Must be locked.");
184 OrderAccess::release_store(&_first, set_state(_first, STATE_REDIRECT_BIT));
185 }
186
187 // InternalTable
188 template <typename VALUE, typename CONFIG, MEMFLAGS F>
189 inline ConcurrentHashTable<VALUE, CONFIG, F>::
190 InternalTable::InternalTable(size_t log2_size)
191 : _log2_size(log2_size), _size(((size_t)1ul) << _log2_size),
192 _hash_mask(~(~((size_t)0) << _log2_size))
193 {
194 assert(_log2_size >= SIZE_SMALL_LOG2 && _log2_size <= SIZE_BIG_LOG2,
195 "Bad size");
196 void* memory = NEW_C_HEAP_ARRAY(Bucket, _size, F);
197 _buckets = new (memory) Bucket[_size];
198 }
199
200 template <typename VALUE, typename CONFIG, MEMFLAGS F>
201 inline ConcurrentHashTable<VALUE, CONFIG, F>::
202 InternalTable::~InternalTable()
203 {
204 FREE_C_HEAP_ARRAY(Bucket, _buckets);
205 }
206
207 // ScopedCS
208 template <typename VALUE, typename CONFIG, MEMFLAGS F>
209 inline ConcurrentHashTable<VALUE, CONFIG, F>::
210 ScopedCS::ScopedCS(Thread* thread, ConcurrentHashTable<VALUE, CONFIG, F>* cht)
211 : _thread(thread), _cht(cht)
212 {
213 GlobalCounter::critical_section_begin(_thread);
214 // This version is published now.
215 if (OrderAccess::load_acquire(&_cht->_invisible_epoch) != NULL) {
216 OrderAccess::release_store_fence(&_cht->_invisible_epoch, (Thread*)NULL);
217 }
218 }
219
220 template <typename VALUE, typename CONFIG, MEMFLAGS F>
221 inline ConcurrentHashTable<VALUE, CONFIG, F>::
222 ScopedCS::~ScopedCS()
223 {
224 GlobalCounter::critical_section_end(_thread);
225 }
226
227 // BaseConfig
228 template <typename VALUE, typename CONFIG, MEMFLAGS F>
229 inline void* ConcurrentHashTable<VALUE, CONFIG, F>::
230 BaseConfig::allocate_node(size_t size, const VALUE& value)
231 {
232 return AllocateHeap(size, F);
233 }
234
235 template <typename VALUE, typename CONFIG, MEMFLAGS F>
236 inline void ConcurrentHashTable<VALUE, CONFIG, F>::
237 BaseConfig::free_node(void* memory, const VALUE& value)
238 {
239 FreeHeap(memory);
240 }
241
242 template <typename VALUE, typename CONFIG, MEMFLAGS F>
243 template <typename LOOKUP_FUNC>
244 inline VALUE* ConcurrentHashTable<VALUE, CONFIG, F>::
245 MultiGetHandle::get(LOOKUP_FUNC& lookup_f, bool* grow_hint)
246 {
247 return ScopedCS::_cht->internal_get(ScopedCS::_thread, lookup_f, grow_hint);
248 }
249
250 // HaveDeletables
251 template <typename VALUE, typename CONFIG, MEMFLAGS F>
252 template <typename EVALUATE_FUNC>
253 inline bool ConcurrentHashTable<VALUE, CONFIG, F>::
254 HaveDeletables<true, EVALUATE_FUNC>::have_deletable(Bucket* bucket,
255 EVALUATE_FUNC& eval_f,
256 Bucket* prefetch_bucket)
257 {
258 // Instantiated for pointer type (true), so we can use prefetch.
259 // When visiting all Nodes doing this prefetch give around 30%.
260 Node* pref = prefetch_bucket != NULL ? prefetch_bucket->first() : NULL;
261 for (Node* next = bucket->first(); next != NULL ; next = next->next()) {
262 if (pref != NULL) {
263 Prefetch::read(*pref->value(), 0);
264 pref = pref->next();
265 }
266 if (next->next() != NULL) {
267 Prefetch::read(*next->next()->value(), 0);
268 }
269 if (eval_f(next->value())) {
270 return true;
271 }
272 }
273 return false;
274 }
275
276 template <typename VALUE, typename CONFIG, MEMFLAGS F>
277 template <bool b, typename EVALUATE_FUNC>
278 inline bool ConcurrentHashTable<VALUE, CONFIG, F>::
279 HaveDeletables<b, EVALUATE_FUNC>::have_deletable(Bucket* bucket,
280 EVALUATE_FUNC& eval_f,
281 Bucket* preb)
282 {
283 for (Node* next = bucket->first(); next != NULL ; next = next->next()) {
284 if (eval_f(next->value())) {
285 return true;
286 }
287 }
288 return false;
289 }
290
291 // ConcurrentHashTable
292 template <typename VALUE, typename CONFIG, MEMFLAGS F>
293 inline void ConcurrentHashTable<VALUE, CONFIG, F>::
294 write_synchonize_on_visible_epoch(Thread* thread)
295 {
296 assert(_resize_lock->owned_by_self(), "Re-size lock not held");
297 OrderAccess::fence(); // Prevent below load from floating up.
298 // If no reader saw this version we can skip write_synchronize.
299 if (OrderAccess::load_acquire(&_invisible_epoch) == thread) {
300 return;
301 }
302 assert(_invisible_epoch == NULL, "Two thread doing bulk operations");
303 // We set this/next version that we are synchronizing for to not published.
304 // A reader will zero this flag if it reads this/next version.
305 OrderAccess::release_store(&_invisible_epoch, thread);
306 GlobalCounter::write_synchronize();
307 }
308
309 template <typename VALUE, typename CONFIG, MEMFLAGS F>
310 inline bool ConcurrentHashTable<VALUE, CONFIG, F>::
311 try_resize_lock(Thread* locker)
312 {
313 if (_resize_lock->try_lock()) {
314 if (_resize_lock_owner != NULL) {
315 assert(locker != _resize_lock_owner, "Already own lock");
316 // We got mutex but internal state is locked.
317 _resize_lock->unlock();
318 return false;
319 }
320 } else {
321 return false;
322 }
323 _invisible_epoch = 0;
324 _resize_lock_owner = locker;
325 return true;
326 }
327
328 template <typename VALUE, typename CONFIG, MEMFLAGS F>
329 inline void ConcurrentHashTable<VALUE, CONFIG, F>::
330 lock_resize_lock(Thread* locker)
331 {
332 size_t i = 0;
333 // If lock is hold by some other thread, the chances that it is return quick
334 // is low. So we will prefer yielding.
335 SpinYield yield(1, 512);
336 do {
337 _resize_lock->lock_without_safepoint_check();
338 // If holder of lock dropped mutex for safepoint mutex might be unlocked,
339 // and _resize_lock_owner will contain the owner.
340 if (_resize_lock_owner != NULL) {
341 assert(locker != _resize_lock_owner, "Already own lock");
342 // We got mutex but internal state is locked.
343 _resize_lock->unlock();
344 yield.wait();
345 } else {
346 break;
347 }
348 } while(true);
349 _resize_lock_owner = locker;
350 _invisible_epoch = 0;
351 }
352
353 template <typename VALUE, typename CONFIG, MEMFLAGS F>
354 inline void ConcurrentHashTable<VALUE, CONFIG, F>::
355 unlock_resize_lock(Thread* locker)
356 {
357 _invisible_epoch = 0;
358 assert(locker == _resize_lock_owner, "Not unlocked by locker.");
359 _resize_lock_owner = NULL;
360 _resize_lock->unlock();
361 }
362
363 template <typename VALUE, typename CONFIG, MEMFLAGS F>
364 inline void ConcurrentHashTable<VALUE, CONFIG, F>::
365 free_nodes()
366 {
367 // We assume we are not MT during freeing.
368 for (size_t node_it = 0; node_it < _table->_size; node_it++) {
369 Bucket* bucket = _table->get_buckets() + node_it;
370 Node* node = bucket->first();
371 while (node != NULL) {
372 Node* free_node = node;
373 node = node->next();
374 Node::destroy_node(free_node);
375 }
376 }
377 }
378
379 template <typename VALUE, typename CONFIG, MEMFLAGS F>
380 inline typename ConcurrentHashTable<VALUE, CONFIG, F>::InternalTable*
381 ConcurrentHashTable<VALUE, CONFIG, F>::
382 get_table() const
383 {
384 return OrderAccess::load_acquire(&_table);
385 }
386
387 template <typename VALUE, typename CONFIG, MEMFLAGS F>
388 inline typename ConcurrentHashTable<VALUE, CONFIG, F>::InternalTable*
389 ConcurrentHashTable<VALUE, CONFIG, F>::
390 get_new_table() const
391 {
392 return OrderAccess::load_acquire(&_new_table);
393 }
394
395 template <typename VALUE, typename CONFIG, MEMFLAGS F>
396 inline typename ConcurrentHashTable<VALUE, CONFIG, F>::InternalTable*
397 ConcurrentHashTable<VALUE, CONFIG, F>::
398 set_table_from_new()
399 {
400 InternalTable* old_table = _table;
401 // Publish the new table.
402 OrderAccess::release_store(&_table, _new_table);
403 // All must see this.
404 GlobalCounter::write_synchronize();
405 // _new_table not read any more.
406 _new_table = NULL;
407 DEBUG_ONLY(_new_table = (InternalTable*)POISON_PTR;)
408 return old_table;
409 }
410
411 template <typename VALUE, typename CONFIG, MEMFLAGS F>
412 inline void ConcurrentHashTable<VALUE, CONFIG, F>::
413 internal_grow_range(Thread* thread, size_t start, size_t stop)
414 {
415 assert(stop <= _table->_size, "Outside backing array");
416 assert(_new_table != NULL, "Grow not proper setup before start");
417 // The state is also copied here. Hence all buckets in new table will be
418 // locked. I call the siblings odd/even, where even have high bit 0 and odd
419 // have high bit 1.
420 for (size_t even_index = start; even_index < stop; even_index++) {
421 Bucket* bucket = _table->get_bucket(even_index);
422
423 bucket->lock();
424
425 size_t odd_index = even_index + _table->_size;
426 _new_table->get_buckets()[even_index] = *bucket;
427 _new_table->get_buckets()[odd_index] = *bucket;
428
429 // Moves lockers go to new table, where they will wait until unlock() below.
430 bucket->redirect(); /* Must release stores above */
431
432 // When this is done we have separated the nodes into corresponding buckets
433 // in new table.
434 if (!unzip_bucket(thread, _table, _new_table, even_index, odd_index)) {
435 // If bucket is empty, unzip does nothing.
436 // We must make sure readers go to new table before we poison the bucket.
437 DEBUG_ONLY(GlobalCounter::write_synchronize();)
438 }
439
440 // Unlock for writes into the new table buckets.
441 _new_table->get_bucket(even_index)->unlock();
442 _new_table->get_bucket(odd_index)->unlock();
443
444 DEBUG_ONLY(
445 bucket->release_assign_node_ptr(
446 _table->get_bucket(even_index)->first_ptr(), (Node*)POISON_PTR);
447 )
448 }
449 }
450
451 template <typename VALUE, typename CONFIG, MEMFLAGS F>
452 template <typename LOOKUP_FUNC, typename DELETE_FUNC>
453 inline bool ConcurrentHashTable<VALUE, CONFIG, F>::
454 internal_remove(Thread* thread, LOOKUP_FUNC& lookup_f, DELETE_FUNC& delete_f)
455 {
456 Bucket* bucket = get_bucket_locked(thread, lookup_f.get_hash());
457 assert(bucket->is_locked(), "Must be locked.");
458 Node* const volatile * rem_n_prev = bucket->first_ptr();
459 Node* rem_n = bucket->first();
460 bool have_dead = false;
461 while (rem_n != NULL) {
462 if (lookup_f.equals(rem_n->value(), &have_dead)) {
463 bucket->release_assign_node_ptr(rem_n_prev, rem_n->next());
464 break;
465 } else {
466 rem_n_prev = rem_n->next_ptr();
467 rem_n = rem_n->next();
468 }
469 }
470
471 bucket->unlock();
472
473 if (rem_n == NULL) {
474 return false;
475 }
476 // Publish the deletion.
477 GlobalCounter::write_synchronize();
478 delete_f(rem_n->value());
479 Node::destroy_node(rem_n);
480 return true;
481 }
482
483 template <typename VALUE, typename CONFIG, MEMFLAGS F>
484 template <typename EVALUATE_FUNC, typename DELETE_FUNC>
485 inline void ConcurrentHashTable<VALUE, CONFIG, F>::
486 do_bulk_delete_locked_for(Thread* thread, size_t start_idx, size_t stop_idx,
487 EVALUATE_FUNC& eval_f, DELETE_FUNC& del_f)
488 {
489 // Here we have resize lock so table is SMR safe, and there is no new
490 // table. Can do this in parallel if we want.
491 assert(_resize_lock->owned_by_self(), "Re-size lock not held");
492 Node* ndel[BULK_DELETE_LIMIT];
493 InternalTable* table = get_table();
494 assert(start_idx < stop_idx, "Must be");
495 assert(stop_idx <= _table->_size, "Must be");
496 // Here manual do critical section since we don't want to take the cost of
497 // locking the bucket if there is nothing to delete. But we can have
498 // concurrent single deletes. The _invisible_epoch can only be used by the
499 // owner of _resize_lock, us here. There we should not changed it in our
500 // own read-side.
501 GlobalCounter::critical_section_begin(thread);
502 for (size_t bucket_it = start_idx; bucket_it < stop_idx; bucket_it++) {
503 Bucket* bucket = _table->get_bucket(bucket_it);
504 Bucket* prefetch_bucket = (bucket_it+1) < stop_idx ?
505 _table->get_bucket(bucket_it+1) : NULL;
506
507 if (!HaveDeletables<IsPointer<VALUE>::value, EVALUATE_FUNC>::
508 have_deletable(bucket, eval_f, prefetch_bucket)) {
509 // Nothing to remove in this bucket.
510 continue;
511 }
512
513 GlobalCounter::critical_section_end(thread);
514 // We left critical section but the bucket cannot be removed while we hold
515 // the _resize_lock.
516 bucket->lock();
517 size_t nd = delete_check_nodes(bucket, eval_f, BULK_DELETE_LIMIT, ndel);
518 bucket->unlock();
519 write_synchonize_on_visible_epoch(thread);
520 for (size_t node_it = 0; node_it < nd; node_it++) {
521 del_f(ndel[node_it]->value());
522 Node::destroy_node(ndel[node_it]);
523 DEBUG_ONLY(ndel[node_it] = (Node*)POISON_PTR;)
524 }
525 GlobalCounter::critical_section_begin(thread);
526 }
527 GlobalCounter::critical_section_end(thread);
528 }
529
530 template <typename VALUE, typename CONFIG, MEMFLAGS F>
531 template <typename LOOKUP_FUNC>
532 inline void ConcurrentHashTable<VALUE, CONFIG, F>::
533 delete_in_bucket(Thread* thread, Bucket* bucket, LOOKUP_FUNC& lookup_f)
534 {
535 size_t dels = 0;
536 Node* ndel[BULK_DELETE_LIMIT];
537 Node* const volatile * rem_n_prev = bucket->first_ptr();
538 Node* rem_n = bucket->first();
539 while (rem_n != NULL) {
540 bool is_dead = false;
541 lookup_f.equals(rem_n->value(), &is_dead);
542 if (is_dead) {
543 ndel[dels++] = rem_n;
544 bucket->release_assign_node_ptr(rem_n_prev, rem_n->next());
545 rem_n = rem_n->next();
546 if (dels == BULK_DELETE_LIMIT) {
547 break;
548 }
549 } else {
550 rem_n_prev = rem_n->next_ptr();
551 rem_n = rem_n->next();
552 }
553 }
554 if (dels > 0) {
555 GlobalCounter::write_synchronize();
556 for (size_t node_it = 0; node_it < dels; node_it++) {
557 Node::destroy_node(ndel[node_it]);
558 DEBUG_ONLY(ndel[node_it] = (Node*)POISON_PTR;)
559 }
560 }
561 }
562
563 template <typename VALUE, typename CONFIG, MEMFLAGS F>
564 inline typename ConcurrentHashTable<VALUE, CONFIG, F>::Bucket*
565 ConcurrentHashTable<VALUE, CONFIG, F>::
566 get_bucket(uintx hash) const
567 {
568 InternalTable* table = get_table();
569 Bucket* bucket = get_bucket_in(table, hash);
570 if (bucket->have_redirect()) {
571 table = get_new_table();
572 bucket = get_bucket_in(table, hash);
573 }
574 return bucket;
575 }
576
577 template <typename VALUE, typename CONFIG, MEMFLAGS F>
578 inline typename ConcurrentHashTable<VALUE, CONFIG, F>::Bucket*
579 ConcurrentHashTable<VALUE, CONFIG, F>::
580 get_bucket_locked(Thread* thread, const uintx hash)
581 {
582 Bucket* bucket;
583 int i = 0;
584 // SpinYield would be unfair here
585 while(true) {
586 {
587 // We need a critical section to protect the table itself. But if we fail
588 // we must leave critical section otherwise we would deadlock.
589 ScopedCS cs(thread, this);
590 bucket = get_bucket(hash);
591 if (bucket->trylock()) {
592 break; /* ends critical section */
593 }
594 } /* ends critical section */
595 if ((++i) == SPINPAUSES_PER_YIELD) {
596 // On contemporary OS yielding will give CPU to another runnable thread if
597 // there is no CPU available.
598 os::naked_yield();
599 i = 0;
600 } else {
601 SpinPause();
602 }
603 }
604 return bucket;
605 }
606
607 // Always called within critical section
608 template <typename VALUE, typename CONFIG, MEMFLAGS F>
609 template <typename LOOKUP_FUNC>
610 typename ConcurrentHashTable<VALUE, CONFIG, F>::Node*
611 ConcurrentHashTable<VALUE, CONFIG, F>::
612 get_node(const Bucket* const bucket, LOOKUP_FUNC& lookup_f,
613 bool* have_dead, size_t* loops) const
614 {
615 size_t loop_count = 0;
616 Node* node = bucket->first();
617 while (node != NULL) {
618 bool is_dead = false;
619 ++loop_count;
620 if (lookup_f.equals(node->value(), &is_dead)) {
621 break;
622 }
623 if (is_dead && !(*have_dead)) {
624 *have_dead = true;
625 }
626 node = node->next();
627 }
628 if (loops != NULL) {
629 *loops = loop_count;
630 }
631 return node;
632 }
633
634 template <typename VALUE, typename CONFIG, MEMFLAGS F>
635 inline bool ConcurrentHashTable<VALUE, CONFIG, F>::
636 unzip_bucket(Thread* thread, InternalTable* old_table,
637 InternalTable* new_table, size_t even_index, size_t odd_index)
638 {
639 Node* aux = old_table->get_bucket(even_index)->first();
640 if (aux == NULL) {
641 // This is an empty bucket and in debug we poison first ptr in bucket.
642 // Therefore we must make sure no readers are looking at this bucket.
643 // If we don't do a write_synch here, caller must do it.
644 return false;
645 }
646 Node* delete_me = NULL;
647 Node* const volatile * even = new_table->get_bucket(even_index)->first_ptr();
648 Node* const volatile * odd = new_table->get_bucket(odd_index)->first_ptr();
649 while (aux != NULL) {
650 bool dead_hash = false;
651 size_t aux_hash = CONFIG::get_hash(*aux->value(), &dead_hash);
652 if (dead_hash) {
653 delete_me = aux;
654 // This item is dead, move both list to next
655 new_table->get_bucket(odd_index)->release_assign_node_ptr(odd,
656 aux->next());
657 new_table->get_bucket(even_index)->release_assign_node_ptr(even,
658 aux->next());
659 } else {
660 size_t aux_index = bucket_idx_hash(new_table, aux_hash);
661 if (aux_index == even_index) {
662 // This is a even, so move odd to aux/even next
663 new_table->get_bucket(odd_index)->release_assign_node_ptr(odd,
664 aux->next());
665 // Keep in even list
666 even = aux->next_ptr();
667 } else if (aux_index == odd_index) {
668 // This is a odd, so move odd to aux/odd next
669 new_table->get_bucket(even_index)->release_assign_node_ptr(even,
670 aux->next());
671 // Keep in odd list
672 odd = aux->next_ptr();
673 } else {
674 fatal("aux_index does not match even or odd indices");
675 }
676 }
677 aux = aux->next();
678
679 // We can only move 1 pointer otherwise a reader might be moved to the wrong
680 // chain. E.g. looking for even hash value but got moved to the odd bucket
681 // chain.
682 write_synchonize_on_visible_epoch(thread);
683 if (delete_me != NULL) {
684 Node::destroy_node(delete_me);
685 delete_me = NULL;
686 }
687 }
688 return true;
689 }
690
691 template <typename VALUE, typename CONFIG, MEMFLAGS F>
692 inline bool ConcurrentHashTable<VALUE, CONFIG, F>::
693 internal_shrink_prolog(Thread* thread, size_t log2_size)
694 {
695 if (!try_resize_lock(thread)) {
696 return false;
697 }
698
699 assert(_resize_lock->owned_by_self(), "Re-size lock not held");
700
701 if (_table->_log2_size == _log2_start_size ||
702 _table->_log2_size <= log2_size) {
703 unlock_resize_lock(thread);
704 return false;
705 }
706
707 _new_table = new InternalTable(_table->_log2_size - 1);
708
709 return true;
710 }
711
712 template <typename VALUE, typename CONFIG, MEMFLAGS F>
713 inline void ConcurrentHashTable<VALUE, CONFIG, F>::
714 internal_shrink_epilog(Thread* thread)
715 {
716 assert(_resize_lock->owned_by_self(), "Re-size lock not held");
717 assert(_resize_lock_owner, "Should be locked");
718
719 InternalTable* old_table = set_table_from_new();
720 _size_limit_reached = false;
721 unlock_resize_lock(thread);
722 #ifdef ASSERT
723 for (size_t i = 0; i < old_table->_size; i++) {
724 assert(old_table->get_bucket(i++)->first() == POISON_PTR,
725 "No poison found");
726 }
727 #endif
728 // ABA safe, old_table not visible to any other threads.
729 delete old_table;
730 }
731
732 template <typename VALUE, typename CONFIG, MEMFLAGS F>
733 inline void ConcurrentHashTable<VALUE, CONFIG, F>::
734 internal_shrink_range(Thread* thread, size_t start, size_t stop)
735 {
736 // The state is also copied here.
737 // Hence all buckets in new table will be locked.
738 for (size_t bucket_it = start; bucket_it < stop; bucket_it++) {
739 size_t even_hash_index = bucket_it; // High bit 0
740 size_t odd_hash_index = bucket_it + _new_table->_size; // High bit 1
741
742 Bucket* b_old_even = _table->get_bucket(even_hash_index);
743 Bucket* b_old_odd = _table->get_bucket(odd_hash_index);
744
745 b_old_even->lock();
746 b_old_odd->lock();
747
748 _new_table->get_buckets()[bucket_it] = *b_old_even;
749
750 // Put chains together.
751 _new_table->get_bucket(bucket_it)->
752 release_assign_last_node_next(*(b_old_odd->first_ptr()));
753
754 b_old_even->redirect();
755 b_old_odd->redirect();
756
757 write_synchonize_on_visible_epoch(thread);
758
759 // Unlock for writes into new smaller table.
760 _new_table->get_bucket(bucket_it)->unlock();
761
762 DEBUG_ONLY(b_old_even->release_assign_node_ptr(b_old_even->first_ptr(),
763 (Node*)POISON_PTR);)
764 DEBUG_ONLY(b_old_odd->release_assign_node_ptr(b_old_odd->first_ptr(),
765 (Node*)POISON_PTR);)
766 }
767 }
768
769 template <typename VALUE, typename CONFIG, MEMFLAGS F>
770 inline bool ConcurrentHashTable<VALUE, CONFIG, F>::
771 internal_shrink(Thread* thread, size_t log2_size)
772 {
773 if (!internal_shrink_prolog(thread, log2_size)) {
774 assert(!_resize_lock->owned_by_self(), "Re-size lock held");
775 return false;
776 }
777 assert(_resize_lock->owned_by_self(), "Re-size lock not held");
778 assert(_resize_lock_owner == thread, "Should be locked by me");
779 internal_shrink_range(thread, 0, _new_table->_size);
780 internal_shrink_epilog(thread);
781 assert(!_resize_lock->owned_by_self(), "Re-size lock not held");
782 return true;
783 }
784
785 template <typename VALUE, typename CONFIG, MEMFLAGS F>
786 inline bool ConcurrentHashTable<VALUE, CONFIG, F>::
787 internal_grow_prolog(Thread* thread, size_t log2_size)
788 {
789 // This double checking of _size_limit_reached/is_max_size_reached()
790 // we only do in grow path, since grow means high load on table
791 // while shrink means low load.
792 if (is_max_size_reached()) {
793 return false;
794 }
795 if (!try_resize_lock(thread)) {
796 // Either we have an ongoing resize or an operation which doesn't want us
797 // to resize now.
798 return false;
799 }
800 if (is_max_size_reached() || _table->_log2_size >= log2_size) {
801 unlock_resize_lock(thread);
802 return false;
803 }
804
805 _new_table = new InternalTable(_table->_log2_size + 1);
806
807 if (_new_table->_log2_size == _log2_size_limit) {
808 _size_limit_reached = true;
809 }
810
811 return true;
812 }
813
814 template <typename VALUE, typename CONFIG, MEMFLAGS F>
815 inline void ConcurrentHashTable<VALUE, CONFIG, F>::
816 internal_grow_epilog(Thread* thread)
817 {
818 assert(_resize_lock->owned_by_self(), "Re-size lock not held");
819 assert(_resize_lock_owner, "Should be locked");
820
821 InternalTable* old_table = set_table_from_new();
822 unlock_resize_lock(thread);
823 #ifdef ASSERT
824 for (size_t i = 0; i < old_table->_size; i++) {
825 assert(old_table->get_bucket(i++)->first() == POISON_PTR,
826 "No poison found");
827 }
828 #endif
829 // ABA safe, old_table not visible to any other threads.
830 delete old_table;
831 }
832
833 template <typename VALUE, typename CONFIG, MEMFLAGS F>
834 inline bool ConcurrentHashTable<VALUE, CONFIG, F>::
835 internal_grow(Thread* thread, size_t log2_size)
836 {
837 if (!internal_grow_prolog(thread, log2_size)) {
838 assert(!_resize_lock->owned_by_self(), "Re-size lock held");
839 return false;
840 }
841 assert(_resize_lock->owned_by_self(), "Re-size lock not held");
842 assert(_resize_lock_owner == thread, "Should be locked by me");
843 internal_grow_range(thread, 0, _table->_size);
844 internal_grow_epilog(thread);
845 assert(!_resize_lock->owned_by_self(), "Re-size lock not held");
846 return true;
847 }
848
849 // Always called within critical section
850 template <typename VALUE, typename CONFIG, MEMFLAGS F>
851 template <typename LOOKUP_FUNC>
852 inline VALUE* ConcurrentHashTable<VALUE, CONFIG, F>::
853 internal_get(Thread* thread, LOOKUP_FUNC& lookup_f, bool* grow_hint)
854 {
855 bool clean = false;
856 size_t loops = 0;
857 VALUE* ret = NULL;
858
859 const Bucket* bucket = get_bucket(lookup_f.get_hash());
860 Node* node = get_node(bucket, lookup_f, &clean, &loops);
861 if (node != NULL) {
862 ret = node->value();
863 }
864 if (grow_hint != NULL) {
865 *grow_hint = loops > _grow_hint;
866 }
867
868 return ret;
869 }
870
871 template <typename VALUE, typename CONFIG, MEMFLAGS F>
872 template <typename LOOKUP_FUNC, typename VALUE_FUNC, typename CALLBACK_FUNC>
873 inline bool ConcurrentHashTable<VALUE, CONFIG, F>::
874 internal_insert(Thread* thread, LOOKUP_FUNC& lookup_f, VALUE_FUNC& value_f,
875 CALLBACK_FUNC& callback, bool* grow_hint)
876 {
877 bool ret = false;
878 bool clean = false;
879 bool locked;
880 size_t loops = 0;
881 size_t i = 0;
882 Node* new_node = NULL;
883 uintx hash = lookup_f.get_hash();
884 while (true) {
885 {
886 ScopedCS cs(thread, this); /* protected the table/bucket */
887 Bucket* bucket = get_bucket(hash);
888
889 Node* first_at_start = bucket->first();
890 Node* old = get_node(bucket, lookup_f, &clean, &loops);
891 if (old == NULL) {
892 // No duplicate found.
893 if (new_node == NULL) {
894 new_node = Node::create_node(value_f(), first_at_start);
895 } else {
896 new_node->set_next(first_at_start);
897 }
898 if (bucket->cas_first(new_node, first_at_start)) {
899 callback(true, new_node->value());
900 new_node = NULL;
901 ret = true;
902 break; /* leave critical section */
903 }
904 // CAS failed we must leave critical section and retry.
905 locked = bucket->is_locked();
906 } else {
907 // There is a duplicate.
908 callback(false, old->value());
909 break; /* leave critical section */
910 }
911 } /* leave critical section */
912 i++;
913 if (locked) {
914 os::naked_yield();
915 } else {
916 SpinPause();
917 }
918 }
919
920 if (new_node != NULL) {
921 // CAS failed and a duplicate was inserted, we must free this node.
922 Node::destroy_node(new_node);
923 } else if (i == 0 && clean) {
924 // We only do cleaning on fast inserts.
925 Bucket* bucket = get_bucket_locked(thread, lookup_f.get_hash());
926 assert(bucket->is_locked(), "Must be locked.");
927 delete_in_bucket(thread, bucket, lookup_f);
928 bucket->unlock();
929 }
930
931 if (grow_hint != NULL) {
932 *grow_hint = loops > _grow_hint;
933 }
934
935 return ret;
936 }
937
938 template <typename VALUE, typename CONFIG, MEMFLAGS F>
939 template <typename FUNC>
940 inline bool ConcurrentHashTable<VALUE, CONFIG, F>::
941 visit_nodes(Bucket* bucket, FUNC& visitor_f)
942 {
943 Node* current_node = bucket->first();
944 while (current_node != NULL) {
945 if (!visitor_f(current_node->value())) {
946 return false;
947 }
948 current_node = current_node->next();
949 }
950 return true;
951 }
952
953 template <typename VALUE, typename CONFIG, MEMFLAGS F>
954 template <typename FUNC>
955 inline void ConcurrentHashTable<VALUE, CONFIG, F>::
956 do_scan_locked(Thread* thread, FUNC& scan_f)
957 {
958 assert(_resize_lock->owned_by_self() ||
959 (thread->is_VM_thread() && SafepointSynchronize::is_at_safepoint()),
960 "Re-size lock not held or not VMThread at safepoint");
961 // We can do a critical section over the entire loop but that would block
962 // updates for a long time. Instead we choose to block resizes.
963 InternalTable* table = get_table();
964 for (size_t bucket_it = 0; bucket_it < _table->_size; bucket_it++) {
965 ScopedCS cs(thread, this);
966 if (!visit_nodes(_table->get_bucket(bucket_it), scan_f)) {
967 break; /* ends critical section */
968 }
969 } /* ends critical section */
970 }
971
972 template <typename VALUE, typename CONFIG, MEMFLAGS F>
973 template <typename EVALUATE_FUNC>
974 inline size_t ConcurrentHashTable<VALUE, CONFIG, F>::
975 delete_check_nodes(Bucket* bucket, EVALUATE_FUNC& eval_f,
976 size_t num_del, Node** ndel)
977 {
978 size_t dels = 0;
979 Node* const volatile * rem_n_prev = bucket->first_ptr();
980 Node* rem_n = bucket->first();
981 while (rem_n != NULL) {
982 if (eval_f(rem_n->value())) {
983 ndel[dels++] = rem_n;
984 bucket->release_assign_node_ptr(rem_n_prev, rem_n->next());
985 rem_n = rem_n->next();
986 if (dels == num_del) {
987 break;
988 }
989 } else {
990 rem_n_prev = rem_n->next_ptr();
991 rem_n = rem_n->next();
992 }
993 }
994 return dels;
995 }
996
997 // Constructor
998 template <typename VALUE, typename CONFIG, MEMFLAGS F>
999 inline ConcurrentHashTable<VALUE, CONFIG, F>::
1000 ConcurrentHashTable(size_t log2size, size_t log2size_limit, size_t grow_hint)
1001 : _new_table(NULL), _log2_start_size(log2size),
1002 _log2_size_limit(log2size_limit), _grow_hint(grow_hint),
1003 _size_limit_reached(false), _resize_lock_owner(NULL),
1004 _invisible_epoch(0)
1005 {
1006 _resize_lock =
1007 new Mutex(Mutex::leaf, "ConcurrentHashTable", false,
1008 Monitor::_safepoint_check_never);
1009 _table = new InternalTable(log2size);
1010 assert(log2size_limit >= log2size, "bad ergo");
1011 _size_limit_reached = _table->_log2_size == _log2_size_limit;
1012 }
1013
1014 template <typename VALUE, typename CONFIG, MEMFLAGS F>
1015 inline ConcurrentHashTable<VALUE, CONFIG, F>::
1016 ~ConcurrentHashTable()
1017 {
1018 delete _resize_lock;
1019 free_nodes();
1020 delete _table;
1021 }
1022
1023 template <typename VALUE, typename CONFIG, MEMFLAGS F>
1024 inline size_t ConcurrentHashTable<VALUE, CONFIG, F>::
1025 get_size_log2(Thread* thread)
1026 {
1027 ScopedCS cs(thread, this);
1028 return _table->_log2_size;
1029 }
1030
1031 template <typename VALUE, typename CONFIG, MEMFLAGS F>
1032 inline bool ConcurrentHashTable<VALUE, CONFIG, F>::
1033 shrink(Thread* thread, size_t size_limit_log2)
1034 {
1035 size_t tmp = size_limit_log2 == 0 ? _log2_start_size : size_limit_log2;
1036 bool ret = internal_shrink(thread, tmp);
1037 return ret;
1038 }
1039
1040 template <typename VALUE, typename CONFIG, MEMFLAGS F>
1041 inline bool ConcurrentHashTable<VALUE, CONFIG, F>::
1042 grow(Thread* thread, size_t size_limit_log2)
1043 {
1044 size_t tmp = size_limit_log2 == 0 ? _log2_size_limit : size_limit_log2;
1045 return internal_grow(thread, tmp);
1046 }
1047
1048 template <typename VALUE, typename CONFIG, MEMFLAGS F>
1049 template <typename LOOKUP_FUNC, typename FOUND_FUNC>
1050 inline bool ConcurrentHashTable<VALUE, CONFIG, F>::
1051 get(Thread* thread, LOOKUP_FUNC& lookup_f, FOUND_FUNC& found_f, bool* grow_hint)
1052 {
1053 bool ret = false;
1054 ScopedCS cs(thread, this);
1055 VALUE* val = internal_get(thread, lookup_f, grow_hint);
1056 if (val != NULL) {
1057 found_f(val);
1058 ret = true;
1059 }
1060 return ret;
1061 }
1062
1063 template <typename VALUE, typename CONFIG, MEMFLAGS F>
1064 template <typename LOOKUP_FUNC>
1065 inline VALUE ConcurrentHashTable<VALUE, CONFIG, F>::
1066 get_copy(Thread* thread, LOOKUP_FUNC& lookup_f, bool* grow_hint)
1067 {
1068 ScopedCS cs(thread, this);
1069 VALUE* val = internal_get(thread, lookup_f, grow_hint);
1070 return val != NULL ? *val : CONFIG::notfound();
1071 }
1072
1073 template <typename VALUE, typename CONFIG, MEMFLAGS F>
1074 inline bool ConcurrentHashTable<VALUE, CONFIG, F>::
1075 unsafe_insert(const VALUE& value) {
1076 bool dead_hash = false;
1077 size_t hash = CONFIG::get_hash(value, &dead_hash);
1078 if (dead_hash) {
1079 return false;
1080 }
1081 // This is an unsafe operation.
1082 InternalTable* table = get_table();
1083 Bucket* bucket = get_bucket_in(table, hash);
1084 assert(!bucket->have_redirect() && !bucket->is_locked(), "bad");
1085 Node* new_node = Node::create_node(value, bucket->first());
1086 if (!bucket->cas_first(new_node, bucket->first())) {
1087 assert(false, "bad");
1088 }
1089 return true;
1090 }
1091
1092 template <typename VALUE, typename CONFIG, MEMFLAGS F>
1093 template <typename SCAN_FUNC>
1094 inline bool ConcurrentHashTable<VALUE, CONFIG, F>::
1095 try_scan(Thread* thread, SCAN_FUNC& scan_f)
1096 {
1097 assert(!_resize_lock->owned_by_self(), "Re-size lock not held");
1098 bool vm_and_safepoint = thread->is_VM_thread() &&
1099 SafepointSynchronize::is_at_safepoint();
1100 if (!vm_and_safepoint && !try_resize_lock(thread)) {
1101 return false;
1102 }
1103 do_scan_locked(thread, scan_f);
1104 if (!vm_and_safepoint) {
1105 unlock_resize_lock(thread);
1106 }
1107 assert(!_resize_lock->owned_by_self(), "Re-size lock not held");
1108 return true;
1109 }
1110
1111 template <typename VALUE, typename CONFIG, MEMFLAGS F>
1112 template <typename SCAN_FUNC>
1113 inline void ConcurrentHashTable<VALUE, CONFIG, F>::
1114 do_scan(Thread* thread, SCAN_FUNC& scan_f)
1115 {
1116 assert(!_resize_lock->owned_by_self(), "Re-size lock not held");
1117 lock_resize_lock(thread);
1118 do_scan_locked(thread, scan_f);
1119 unlock_resize_lock(thread);
1120 assert(!_resize_lock->owned_by_self(), "Re-size lock not held");
1121 }
1122
1123 template <typename VALUE, typename CONFIG, MEMFLAGS F>
1124 template <typename EVALUATE_FUNC, typename DELETE_FUNC>
1125 inline bool ConcurrentHashTable<VALUE, CONFIG, F>::
1126 try_bulk_delete(Thread* thread, EVALUATE_FUNC& eval_f, DELETE_FUNC& del_f)
1127 {
1128 if (!try_resize_lock(thread)) {
1129 assert(!_resize_lock->owned_by_self(), "Re-size lock not held");
1130 return false;
1131 }
1132 do_bulk_delete_locked(thread, eval_f, del_f);
1133 unlock_resize_lock(thread);
1134 assert(!_resize_lock->owned_by_self(), "Re-size lock not held");
1135 return true;
1136 }
1137
1138 template <typename VALUE, typename CONFIG, MEMFLAGS F>
1139 template <typename EVALUATE_FUNC, typename DELETE_FUNC>
1140 inline void ConcurrentHashTable<VALUE, CONFIG, F>::
1141 bulk_delete(Thread* thread, EVALUATE_FUNC& eval_f, DELETE_FUNC& del_f)
1142 {
1143 assert(!_resize_lock->owned_by_self(), "Re-size lock not held");
1144 lock_resize_lock(thread);
1145 do_bulk_delete_locked(thread, eval_f, del_f);
1146 unlock_resize_lock(thread);
1147 assert(!_resize_lock->owned_by_self(), "Re-size lock not held");
1148 }
1149
1150 template <typename VALUE, typename CONFIG, MEMFLAGS F>
1151 template <typename VALUE_SIZE_FUNC>
1152 inline void ConcurrentHashTable<VALUE, CONFIG, F>::
1153 statistics_to(Thread* thread, VALUE_SIZE_FUNC& vs_f,
1154 outputStream* st, const char* table_name)
1155 {
1156 NumberSeq summary;
1157 size_t literal_bytes = 0;
1158 if ((thread->is_VM_thread() && !SafepointSynchronize::is_at_safepoint()) ||
1159 (!thread->is_VM_thread() && !try_resize_lock(thread))) {
1160 st->print_cr("statistics unavailable at this moment");
1161 return;
1162 }
1163
1164 InternalTable* table = get_table();
1165 for (size_t bucket_it = 0; bucket_it < _table->_size; bucket_it++) {
1166 ScopedCS cs(thread, this);
1167 size_t count = 0;
1168 Bucket* bucket = _table->get_bucket(bucket_it);
1169 if (bucket->have_redirect() || bucket->is_locked()) {
1170 continue;
1171 }
1172 Node* current_node = bucket->first();
1173 while (current_node != NULL) {
1174 ++count;
1175 literal_bytes += vs_f(current_node->value());
1176 current_node = current_node->next();
1177 }
1178 summary.add((double)count);
1179 }
1180
1181 double num_buckets = summary.num();
1182 double num_entries = summary.sum();
1183
1184 size_t bucket_bytes = num_buckets * sizeof(Bucket);
1185 size_t entry_bytes = num_entries * sizeof(Node);
1186 size_t total_bytes = literal_bytes + bucket_bytes + entry_bytes;
1187
1188 size_t bucket_size = (num_buckets <= 0) ? 0 : (bucket_bytes / num_buckets);
1189 size_t entry_size = (num_entries <= 0) ? 0 : (entry_bytes / num_entries);
1190
1191 st->print_cr("%s statistics:", table_name);
1192 st->print_cr("Number of buckets : %9" PRIuPTR " = %9" PRIuPTR
1193 " bytes, each " SIZE_FORMAT,
1194 (size_t)num_buckets, bucket_bytes, bucket_size);
1195 st->print_cr("Number of entries : %9" PRIuPTR " = %9" PRIuPTR
1196 " bytes, each " SIZE_FORMAT,
1197 (size_t)num_entries, entry_bytes, entry_size);
1198 if (literal_bytes != 0) {
1199 double literal_avg = (num_entries <= 0) ? 0 : (literal_bytes / num_entries);
1200 st->print_cr("Number of literals : %9" PRIuPTR " = %9" PRIuPTR
1201 " bytes, avg %7.3f",
1202 (size_t)num_entries, literal_bytes, literal_avg);
1203 }
1204 st->print_cr("Total footprsize_t : %9s = %9" PRIuPTR " bytes", ""
1205 , total_bytes);
1206 st->print_cr("Average bucket size : %9.3f", summary.avg());
1207 st->print_cr("Variance of bucket size : %9.3f", summary.variance());
1208 st->print_cr("Std. dev. of bucket size: %9.3f", summary.sd());
1209 st->print_cr("Maximum bucket size : %9" PRIuPTR,
1210 (size_t)summary.maximum());
1211 if (!thread->is_VM_thread()) {
1212 unlock_resize_lock(thread);
1213 }
1214 }
1215
1216 #endif // include guard