1 /* 2 * Copyright (c) 2014, 2015, 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/stringTable.hpp" 27 #include "gc/g1/g1StringDedup.hpp" 28 #include "gc/g1/g1StringDedupQueue.hpp" 29 #include "gc/g1/g1StringDedupTable.hpp" 30 #include "gc/g1/g1StringDedupThread.hpp" 31 #include "gc/g1/suspendibleThreadSet.hpp" 32 #include "logging/log.hpp" 33 #include "oops/oop.inline.hpp" 34 #include "runtime/atomic.inline.hpp" 35 36 G1StringDedupThread* G1StringDedupThread::_thread = NULL; 37 38 G1StringDedupThread::G1StringDedupThread() : 39 ConcurrentGCThread() { 40 set_name("G1 StrDedup"); 41 create_and_start(); 42 } 43 44 G1StringDedupThread::~G1StringDedupThread() { 45 ShouldNotReachHere(); 46 } 47 48 void G1StringDedupThread::create() { 49 assert(G1StringDedup::is_enabled(), "String deduplication not enabled"); 50 assert(_thread == NULL, "One string deduplication thread allowed"); 51 _thread = new G1StringDedupThread(); 52 } 53 54 G1StringDedupThread* G1StringDedupThread::thread() { 55 assert(G1StringDedup::is_enabled(), "String deduplication not enabled"); 56 assert(_thread != NULL, "String deduplication thread not created"); 57 return _thread; 58 } 59 60 class G1StringDedupSharedClosure: public OopClosure { 61 private: 62 G1StringDedupStat& _stat; 63 64 public: 65 G1StringDedupSharedClosure(G1StringDedupStat& stat) : _stat(stat) {} 66 67 virtual void do_oop(oop* p) { ShouldNotReachHere(); } 68 virtual void do_oop(narrowOop* p) { 69 oop java_string = oopDesc::load_decode_heap_oop(p); 70 G1StringDedupTable::deduplicate(java_string, _stat); 71 } 72 }; 73 74 // The CDS archive does not include the string dedupication table. Only the string 75 // table is saved in the archive. The shared strings from CDS archive need to be 76 // added to the string dedupication table before deduplication occurs. That is 77 // done in the begining of the G1StringDedupThread (see G1StringDedupThread::run() 78 // below). 79 void G1StringDedupThread::deduplicate_shared_strings(G1StringDedupStat& stat) { 80 G1StringDedupSharedClosure sharedStringDedup(stat); 81 StringTable::shared_oops_do(&sharedStringDedup); 82 } 83 84 void G1StringDedupThread::run() { 85 G1StringDedupStat total_stat; 86 87 initialize_in_thread(); 88 wait_for_universe_init(); 89 deduplicate_shared_strings(total_stat); 90 91 // Main loop 92 for (;;) { 93 G1StringDedupStat stat; 94 95 stat.mark_idle(); 96 97 // Wait for the queue to become non-empty 98 G1StringDedupQueue::wait(); 99 if (_should_terminate) { 100 break; 101 } 102 103 { 104 // Include thread in safepoints 105 SuspendibleThreadSetJoiner sts_join; 106 107 stat.mark_exec(); 108 109 // Process the queue 110 for (;;) { 111 oop java_string = G1StringDedupQueue::pop(); 112 if (java_string == NULL) { 113 break; 114 } 115 116 G1StringDedupTable::deduplicate(java_string, stat); 117 118 // Safepoint this thread if needed 119 if (sts_join.should_yield()) { 120 stat.mark_block(); 121 sts_join.yield(); 122 stat.mark_unblock(); 123 } 124 } 125 126 G1StringDedupTable::trim_entry_cache(); 127 128 stat.mark_done(); 129 130 // Print statistics 131 total_stat.add(stat); 132 print(stat, total_stat); 133 } 134 } 135 136 terminate(); 137 } 138 139 void G1StringDedupThread::stop() { 140 { 141 MonitorLockerEx ml(Terminator_lock); 142 _thread->_should_terminate = true; 143 } 144 145 G1StringDedupQueue::cancel_wait(); 146 147 { 148 MonitorLockerEx ml(Terminator_lock); 149 while (!_thread->_has_terminated) { 150 ml.wait(); 151 } 152 } 153 } 154 155 void G1StringDedupThread::print(const G1StringDedupStat& last_stat, const G1StringDedupStat& total_stat) { 156 if (log_is_enabled(Info, gc, stringdedup)) { 157 G1StringDedupStat::print_summary(last_stat, total_stat); 158 if (log_is_enabled(Debug, gc, stringdedup)) { 159 G1StringDedupStat::print_statistics(last_stat, false); 160 G1StringDedupStat::print_statistics(total_stat, true); 161 G1StringDedupTable::print_statistics(); 162 G1StringDedupQueue::print_statistics(); 163 } 164 } 165 }