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comparison: src/share/vm/gc_implementation/g1/g1StringDedup.cpp
src/share/vm/gc_implementation/g1/g1StringDedup.cpp
- changeset 6413
- 595c0f60d50d
- child 6690
- 1772223a25a2
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| 6412:6e7e363c5a8f | 6413:595c0f60d50d |
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| 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/g1CollectedHeap.inline.hpp" | |
| 28 #include "gc_implementation/g1/g1GCPhaseTimes.hpp" | |
| 29 #include "gc_implementation/g1/g1StringDedup.hpp" | |
| 30 #include "gc_implementation/g1/g1StringDedupQueue.hpp" | |
| 31 #include "gc_implementation/g1/g1StringDedupStat.hpp" | |
| 32 #include "gc_implementation/g1/g1StringDedupTable.hpp" | |
| 33 #include "gc_implementation/g1/g1StringDedupThread.hpp" | |
| 34 | |
| 35 bool G1StringDedup::_enabled = false; | |
| 36 | |
| 37 void G1StringDedup::initialize() { | |
| 38 assert(UseG1GC, "String deduplication only available with G1"); | |
| 39 if (UseStringDeduplication) { | |
| 40 _enabled = true; | |
| 41 G1StringDedupQueue::create(); | |
| 42 G1StringDedupTable::create(); | |
| 43 G1StringDedupThread::create(); | |
| 44 } | |
| 45 } | |
| 46 | |
| 47 bool G1StringDedup::is_candidate_from_mark(oop obj) { | |
| 48 if (java_lang_String::is_instance(obj)) { | |
| 49 bool from_young = G1CollectedHeap::heap()->heap_region_containing_raw(obj)->is_young(); | |
| 50 if (from_young && obj->age() < StringDeduplicationAgeThreshold) { | |
| 51 // Candidate found. String is being evacuated from young to old but has not | |
| 52 // reached the deduplication age threshold, i.e. has not previously been a | |
| 53 // candidate during its life in the young generation. | |
| 54 return true; | |
| 55 } | |
| 56 } | |
| 57 | |
| 58 // Not a candidate | |
| 59 return false; | |
| 60 } | |
| 61 | |
| 62 void G1StringDedup::enqueue_from_mark(oop java_string) { | |
| 63 assert(is_enabled(), "String deduplication not enabled"); | |
| 64 if (is_candidate_from_mark(java_string)) { | |
| 65 G1StringDedupQueue::push(0 /* worker_id */, java_string); | |
| 66 } | |
| 67 } | |
| 68 | |
| 69 bool G1StringDedup::is_candidate_from_evacuation(bool from_young, bool to_young, oop obj) { | |
| 70 if (from_young && java_lang_String::is_instance(obj)) { | |
| 71 if (to_young && obj->age() == StringDeduplicationAgeThreshold) { | |
| 72 // Candidate found. String is being evacuated from young to young and just | |
| 73 // reached the deduplication age threshold. | |
| 74 return true; | |
| 75 } | |
| 76 if (!to_young && obj->age() < StringDeduplicationAgeThreshold) { | |
| 77 // Candidate found. String is being evacuated from young to old but has not | |
| 78 // reached the deduplication age threshold, i.e. has not previously been a | |
| 79 // candidate during its life in the young generation. | |
| 80 return true; | |
| 81 } | |
| 82 } | |
| 83 | |
| 84 // Not a candidate | |
| 85 return false; | |
| 86 } | |
| 87 | |
| 88 void G1StringDedup::enqueue_from_evacuation(bool from_young, bool to_young, uint worker_id, oop java_string) { | |
| 89 assert(is_enabled(), "String deduplication not enabled"); | |
| 90 if (is_candidate_from_evacuation(from_young, to_young, java_string)) { | |
| 91 G1StringDedupQueue::push(worker_id, java_string); | |
| 92 } | |
| 93 } | |
| 94 | |
| 95 void G1StringDedup::deduplicate(oop java_string) { | |
| 96 assert(is_enabled(), "String deduplication not enabled"); | |
| 97 G1StringDedupStat dummy; // Statistics from this path is never used | |
| 98 G1StringDedupTable::deduplicate(java_string, dummy); | |
| 99 } | |
| 100 | |
| 101 void G1StringDedup::oops_do(OopClosure* keep_alive) { | |
| 102 assert(is_enabled(), "String deduplication not enabled"); | |
| 103 unlink_or_oops_do(NULL, keep_alive); | |
| 104 } | |
| 105 | |
| 106 void G1StringDedup::unlink(BoolObjectClosure* is_alive) { | |
| 107 assert(is_enabled(), "String deduplication not enabled"); | |
| 108 // Don't allow a potential resize or rehash during unlink, as the unlink | |
| 109 // operation itself might remove enough entries to invalidate such a decision. | |
| 110 unlink_or_oops_do(is_alive, NULL, false /* allow_resize_and_rehash */); | |
| 111 } | |
| 112 | |
| 113 // | |
| 114 // Task for parallel unlink_or_oops_do() operation on the deduplication queue | |
| 115 // and table. | |
| 116 // | |
| 117 class G1StringDedupUnlinkOrOopsDoTask : public AbstractGangTask { | |
| 118 private: | |
| 119 G1StringDedupUnlinkOrOopsDoClosure _cl; | |
| 120 | |
| 121 public: | |
| 122 G1StringDedupUnlinkOrOopsDoTask(BoolObjectClosure* is_alive, | |
| 123 OopClosure* keep_alive, | |
| 124 bool allow_resize_and_rehash) : | |
| 125 AbstractGangTask("G1StringDedupUnlinkOrOopsDoTask"), | |
| 126 _cl(is_alive, keep_alive, allow_resize_and_rehash) { | |
| 127 } | |
| 128 | |
| 129 virtual void work(uint worker_id) { | |
| 130 double queue_fixup_start = os::elapsedTime(); | |
| 131 G1StringDedupQueue::unlink_or_oops_do(&_cl); | |
| 132 | |
| 133 double table_fixup_start = os::elapsedTime(); | |
| 134 G1StringDedupTable::unlink_or_oops_do(&_cl, worker_id); | |
| 135 | |
| 136 double queue_fixup_time_ms = (table_fixup_start - queue_fixup_start) * 1000.0; | |
| 137 double table_fixup_time_ms = (os::elapsedTime() - table_fixup_start) * 1000.0; | |
| 138 G1CollectorPolicy* g1p = G1CollectedHeap::heap()->g1_policy(); | |
| 139 g1p->phase_times()->record_string_dedup_queue_fixup_worker_time(worker_id, queue_fixup_time_ms); | |
| 140 g1p->phase_times()->record_string_dedup_table_fixup_worker_time(worker_id, table_fixup_time_ms); | |
| 141 } | |
| 142 }; | |
| 143 | |
| 144 void G1StringDedup::unlink_or_oops_do(BoolObjectClosure* is_alive, OopClosure* keep_alive, bool allow_resize_and_rehash) { | |
| 145 assert(is_enabled(), "String deduplication not enabled"); | |
| 146 G1CollectorPolicy* g1p = G1CollectedHeap::heap()->g1_policy(); | |
| 147 g1p->phase_times()->note_string_dedup_fixup_start(); | |
| 148 double fixup_start = os::elapsedTime(); | |
| 149 | |
| 150 G1StringDedupUnlinkOrOopsDoTask task(is_alive, keep_alive, allow_resize_and_rehash); | |
| 151 if (G1CollectedHeap::use_parallel_gc_threads()) { | |
| 152 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 153 g1h->set_par_threads(); | |
| 154 g1h->workers()->run_task(&task); | |
| 155 g1h->set_par_threads(0); | |
| 156 } else { | |
| 157 task.work(0); | |
| 158 } | |
| 159 | |
| 160 double fixup_time_ms = (os::elapsedTime() - fixup_start) * 1000.0; | |
| 161 g1p->phase_times()->record_string_dedup_fixup_time(fixup_time_ms); | |
| 162 g1p->phase_times()->note_string_dedup_fixup_end(); | |
| 163 } | |
| 164 | |
| 165 void G1StringDedup::threads_do(ThreadClosure* tc) { | |
| 166 assert(is_enabled(), "String deduplication not enabled"); | |
| 167 tc->do_thread(G1StringDedupThread::thread()); | |
| 168 } | |
| 169 | |
| 170 void G1StringDedup::print_worker_threads_on(outputStream* st) { | |
| 171 assert(is_enabled(), "String deduplication not enabled"); | |
| 172 G1StringDedupThread::thread()->print_on(st); | |
| 173 st->cr(); | |
| 174 } | |
| 175 | |
| 176 void G1StringDedup::verify() { | |
| 177 assert(is_enabled(), "String deduplication not enabled"); | |
| 178 G1StringDedupQueue::verify(); | |
| 179 G1StringDedupTable::verify(); | |
| 180 } | |
| 181 | |
| 182 G1StringDedupUnlinkOrOopsDoClosure::G1StringDedupUnlinkOrOopsDoClosure(BoolObjectClosure* is_alive, | |
| 183 OopClosure* keep_alive, | |
| 184 bool allow_resize_and_rehash) : | |
| 185 _is_alive(is_alive), | |
| 186 _keep_alive(keep_alive), | |
| 187 _resized_table(NULL), | |
| 188 _rehashed_table(NULL), | |
| 189 _next_queue(0), | |
| 190 _next_bucket(0) { | |
| 191 if (allow_resize_and_rehash) { | |
| 192 // If both resize and rehash is needed, only do resize. Rehash of | |
| 193 // the table will eventually happen if the situation persists. | |
| 194 _resized_table = G1StringDedupTable::prepare_resize(); | |
| 195 if (!is_resizing()) { | |
| 196 _rehashed_table = G1StringDedupTable::prepare_rehash(); | |
| 197 } | |
| 198 } | |
| 199 } | |
| 200 | |
| 201 G1StringDedupUnlinkOrOopsDoClosure::~G1StringDedupUnlinkOrOopsDoClosure() { | |
| 202 assert(!is_resizing() || !is_rehashing(), "Can not both resize and rehash"); | |
| 203 if (is_resizing()) { | |
| 204 G1StringDedupTable::finish_resize(_resized_table); | |
| 205 } else if (is_rehashing()) { | |
| 206 G1StringDedupTable::finish_rehash(_rehashed_table); | |
| 207 } | |
| 208 } |
