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 "gc/g1/g1Log.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 "runtime/atomic.inline.hpp"
  33 
  34 G1StringDedupThread* G1StringDedupThread::_thread = NULL;
  35 
  36 G1StringDedupThread::G1StringDedupThread() :
  37   ConcurrentGCThread() {
  38   set_name("G1 StrDedup");
  39   create_and_start();
  40 }
  41 
  42 G1StringDedupThread::~G1StringDedupThread() {
  43   ShouldNotReachHere();
  44 }
  45 
  46 void G1StringDedupThread::create() {
  47   assert(G1StringDedup::is_enabled(), "String deduplication not enabled");
  48   assert(_thread == NULL, "One string deduplication thread allowed");
  49   _thread = new G1StringDedupThread();
  50 }
  51 
  52 G1StringDedupThread* G1StringDedupThread::thread() {
  53   assert(G1StringDedup::is_enabled(), "String deduplication not enabled");
  54   assert(_thread != NULL, "String deduplication thread not created");
  55   return _thread;
  56 }
  57 
  58 void G1StringDedupThread::run() {
  59   G1StringDedupStat total_stat;
  60 
  61   initialize_in_thread();
  62   wait_for_universe_init();
  63 
  64   // Main loop
  65   for (;;) {
  66     G1StringDedupStat stat;
  67 
  68     stat.mark_idle();
  69 
  70     // Wait for the queue to become non-empty
  71     G1StringDedupQueue::wait();
  72     if (_should_terminate) {
  73       break;
  74     }
  75 
  76     {
  77       // Include thread in safepoints
  78       SuspendibleThreadSetJoiner sts_join;
  79 
  80       stat.mark_exec();
  81 
  82       // Process the queue
  83       for (;;) {
  84         oop java_string = G1StringDedupQueue::pop();
  85         if (java_string == NULL) {
  86           break;
  87         }
  88 
  89         G1StringDedupTable::deduplicate(java_string, stat);
  90 
  91         // Safepoint this thread if needed
  92         if (sts_join.should_yield()) {
  93           stat.mark_block();
  94           sts_join.yield();
  95           stat.mark_unblock();
  96         }
  97       }
  98 
  99       G1StringDedupTable::trim_entry_cache();
 100 
 101       stat.mark_done();
 102 
 103       // Print statistics
 104       total_stat.add(stat);
 105       print(gclog_or_tty, stat, total_stat);
 106     }
 107   }
 108 
 109   terminate();
 110 }
 111 
 112 void G1StringDedupThread::stop() {
 113   {
 114     MonitorLockerEx ml(Terminator_lock);
 115     _thread->_should_terminate = true;
 116   }
 117 
 118   G1StringDedupQueue::cancel_wait();
 119 
 120   {
 121     MonitorLockerEx ml(Terminator_lock);
 122     while (!_thread->_has_terminated) {
 123       ml.wait();
 124     }
 125   }
 126 }
 127 
 128 void G1StringDedupThread::print(outputStream* st, const G1StringDedupStat& last_stat, const G1StringDedupStat& total_stat) {
 129   if (G1Log::fine() || PrintStringDeduplicationStatistics) {
 130     G1StringDedupStat::print_summary(st, last_stat, total_stat);
 131     if (PrintStringDeduplicationStatistics) {
 132       G1StringDedupStat::print_statistics(st, last_stat, false);
 133       G1StringDedupStat::print_statistics(st, total_stat, true);
 134       G1StringDedupTable::print_statistics(st);
 135       G1StringDedupQueue::print_statistics(st);
 136     }
 137   }
 138 }