1 /* 2 * Copyright (c) 2014, 2017, 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/shared/suspendibleThreadSet.hpp" 32 #include "logging/log.hpp" 33 #include "oops/oop.inline.hpp" 34 #include "runtime/atomic.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_service() { 85 G1StringDedupStat total_stat; 86 87 deduplicate_shared_strings(total_stat); 88 89 // Main loop 90 for (;;) { 91 G1StringDedupStat stat; 92 93 stat.mark_idle(); 94 95 // Wait for the queue to become non-empty 96 G1StringDedupQueue::wait(); 97 if (should_terminate()) { 98 break; 99 } 100 101 { 102 // Include thread in safepoints 103 SuspendibleThreadSetJoiner sts_join; 104 105 stat.mark_exec(); 106 print_start(stat); 107 108 // Process the queue 109 for (;;) { 110 oop java_string = G1StringDedupQueue::pop(); 111 if (java_string == NULL) { 112 break; 113 } 114 115 G1StringDedupTable::deduplicate(java_string, stat); 116 117 // Safepoint this thread if needed 118 if (sts_join.should_yield()) { 119 stat.mark_block(); 120 sts_join.yield(); 121 stat.mark_unblock(); 122 } 123 } 124 125 stat.mark_done(); 126 127 total_stat.add(stat); 128 print_end(stat, total_stat); 129 } 130 131 G1StringDedupTable::clean_entry_cache(); 132 } 133 } 134 135 void G1StringDedupThread::stop_service() { 136 G1StringDedupQueue::cancel_wait(); 137 } 138 139 void G1StringDedupThread::print_start(const G1StringDedupStat& last_stat) { 140 G1StringDedupStat::print_start(last_stat); 141 } 142 143 void G1StringDedupThread::print_end(const G1StringDedupStat& last_stat, const G1StringDedupStat& total_stat) { 144 G1StringDedupStat::print_end(last_stat, total_stat); 145 if (log_is_enabled(Debug, gc, stringdedup)) { 146 G1StringDedupStat::print_statistics(last_stat, false); 147 G1StringDedupStat::print_statistics(total_stat, true); 148 G1StringDedupTable::print_statistics(); 149 G1StringDedupQueue::print_statistics(); 150 } 151 }