Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/g1/g1StringDedupQueue.cpp @ 20504:6948da6d7c13
8052172: Evacuation failure handling in G1 does not evacuate all objects if -XX:-G1DeferredRSUpdate is set
Summary: Remove -XX:-G1DeferredRSUpdate functionality as it is racy. During evacuation failure handling, threads where evacuation failure handling occurred may try to add remembered sets to regions which remembered sets are currently being scanned. The iterator to handle the remembered set scan does not support addition of entries during scan and so may skip valid references.
Reviewed-by: iveresov, brutisso, mgerdin
| author | tschatzl |
|---|---|
| date | Tue, 30 Sep 2014 09:44:36 +0200 |
| parents | 1772223a25a2 |
| children |
| rev | line source |
|---|---|
| 17764 | 1 /* |
| 2 * Copyright (c) 2014, 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 #include "precompiled.hpp" | |
| 26 #include "classfile/javaClasses.hpp" | |
| 27 #include "gc_implementation/g1/g1StringDedupQueue.hpp" | |
| 28 #include "memory/gcLocker.hpp" | |
| 29 #include "runtime/mutexLocker.hpp" | |
| 30 #include "utilities/stack.inline.hpp" | |
| 31 | |
| 32 G1StringDedupQueue* G1StringDedupQueue::_queue = NULL; | |
| 33 const size_t G1StringDedupQueue::_max_size = 1000000; // Max number of elements per queue | |
| 34 const size_t G1StringDedupQueue::_max_cache_size = 0; // Max cache size per queue | |
| 35 | |
| 36 G1StringDedupQueue::G1StringDedupQueue() : | |
| 37 _cursor(0), | |
|
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38 _cancel(false), |
| 17764 | 39 _empty(true), |
| 40 _dropped(0) { | |
| 41 _nqueues = MAX2(ParallelGCThreads, (size_t)1); | |
| 42 _queues = NEW_C_HEAP_ARRAY(G1StringDedupWorkerQueue, _nqueues, mtGC); | |
| 43 for (size_t i = 0; i < _nqueues; i++) { | |
| 44 new (_queues + i) G1StringDedupWorkerQueue(G1StringDedupWorkerQueue::default_segment_size(), _max_cache_size, _max_size); | |
| 45 } | |
| 46 } | |
| 47 | |
| 48 G1StringDedupQueue::~G1StringDedupQueue() { | |
| 49 ShouldNotReachHere(); | |
| 50 } | |
| 51 | |
| 52 void G1StringDedupQueue::create() { | |
| 53 assert(_queue == NULL, "One string deduplication queue allowed"); | |
| 54 _queue = new G1StringDedupQueue(); | |
| 55 } | |
| 56 | |
| 57 void G1StringDedupQueue::wait() { | |
| 58 MonitorLockerEx ml(StringDedupQueue_lock, Mutex::_no_safepoint_check_flag); | |
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59 while (_queue->_empty && !_queue->_cancel) { |
| 17764 | 60 ml.wait(Mutex::_no_safepoint_check_flag); |
| 61 } | |
| 62 } | |
| 63 | |
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64 void G1StringDedupQueue::cancel_wait() { |
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65 MonitorLockerEx ml(StringDedupQueue_lock, Mutex::_no_safepoint_check_flag); |
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66 _queue->_cancel = true; |
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67 ml.notify(); |
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68 } |
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69 |
| 17764 | 70 void G1StringDedupQueue::push(uint worker_id, oop java_string) { |
| 71 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint"); | |
| 72 assert(worker_id < _queue->_nqueues, "Invalid queue"); | |
| 73 | |
| 74 // Push and notify waiter | |
| 75 G1StringDedupWorkerQueue& worker_queue = _queue->_queues[worker_id]; | |
| 76 if (!worker_queue.is_full()) { | |
| 77 worker_queue.push(java_string); | |
| 78 if (_queue->_empty) { | |
| 79 MonitorLockerEx ml(StringDedupQueue_lock, Mutex::_no_safepoint_check_flag); | |
| 80 if (_queue->_empty) { | |
| 81 // Mark non-empty and notify waiter | |
| 82 _queue->_empty = false; | |
| 83 ml.notify(); | |
| 84 } | |
| 85 } | |
| 86 } else { | |
| 87 // Queue is full, drop the string and update the statistics | |
| 88 Atomic::inc_ptr(&_queue->_dropped); | |
| 89 } | |
| 90 } | |
| 91 | |
| 92 oop G1StringDedupQueue::pop() { | |
| 93 assert(!SafepointSynchronize::is_at_safepoint(), "Must not be at safepoint"); | |
| 94 No_Safepoint_Verifier nsv; | |
| 95 | |
| 96 // Try all queues before giving up | |
| 97 for (size_t tries = 0; tries < _queue->_nqueues; tries++) { | |
| 98 // The cursor indicates where we left of last time | |
| 99 G1StringDedupWorkerQueue* queue = &_queue->_queues[_queue->_cursor]; | |
| 100 while (!queue->is_empty()) { | |
| 101 oop obj = queue->pop(); | |
| 102 // The oop we pop can be NULL if it was marked | |
| 103 // dead. Just ignore those and pop the next oop. | |
| 104 if (obj != NULL) { | |
| 105 return obj; | |
| 106 } | |
| 107 } | |
| 108 | |
| 109 // Try next queue | |
| 110 _queue->_cursor = (_queue->_cursor + 1) % _queue->_nqueues; | |
| 111 } | |
| 112 | |
| 113 // Mark empty | |
| 114 _queue->_empty = true; | |
| 115 | |
| 116 return NULL; | |
| 117 } | |
| 118 | |
| 119 void G1StringDedupQueue::unlink_or_oops_do(G1StringDedupUnlinkOrOopsDoClosure* cl) { | |
| 120 // A worker thread first claims a queue, which ensures exclusive | |
| 121 // access to that queue, then continues to process it. | |
| 122 for (;;) { | |
| 123 // Grab next queue to scan | |
| 124 size_t queue = cl->claim_queue(); | |
| 125 if (queue >= _queue->_nqueues) { | |
| 126 // End of queues | |
| 127 break; | |
| 128 } | |
| 129 | |
| 130 // Scan the queue | |
| 131 unlink_or_oops_do(cl, queue); | |
| 132 } | |
| 133 } | |
| 134 | |
| 135 void G1StringDedupQueue::unlink_or_oops_do(G1StringDedupUnlinkOrOopsDoClosure* cl, size_t queue) { | |
| 136 assert(queue < _queue->_nqueues, "Invalid queue"); | |
| 137 StackIterator<oop, mtGC> iter(_queue->_queues[queue]); | |
| 138 while (!iter.is_empty()) { | |
| 139 oop* p = iter.next_addr(); | |
| 140 if (*p != NULL) { | |
| 141 if (cl->is_alive(*p)) { | |
| 142 cl->keep_alive(p); | |
| 143 } else { | |
| 144 // Clear dead reference | |
| 145 *p = NULL; | |
| 146 } | |
| 147 } | |
| 148 } | |
| 149 } | |
| 150 | |
| 151 void G1StringDedupQueue::print_statistics(outputStream* st) { | |
| 152 st->print_cr( | |
| 153 " [Queue]\n" | |
| 154 " [Dropped: "UINTX_FORMAT"]", _queue->_dropped); | |
| 155 } | |
| 156 | |
| 157 void G1StringDedupQueue::verify() { | |
| 158 for (size_t i = 0; i < _queue->_nqueues; i++) { | |
| 159 StackIterator<oop, mtGC> iter(_queue->_queues[i]); | |
| 160 while (!iter.is_empty()) { | |
| 161 oop obj = iter.next(); | |
| 162 if (obj != NULL) { | |
| 163 guarantee(Universe::heap()->is_in_reserved(obj), "Object must be on the heap"); | |
| 164 guarantee(!obj->is_forwarded(), "Object must not be forwarded"); | |
| 165 guarantee(java_lang_String::is_instance(obj), "Object must be a String"); | |
| 166 } | |
| 167 } | |
| 168 } | |
| 169 } |