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_implementation/g1/g1Log.hpp"
  27 #include "gc_implementation/g1/g1StringDedup.hpp"
  28 #include "gc_implementation/g1/g1StringDedupTable.hpp"
  29 #include "gc_implementation/g1/g1StringDedupThread.hpp"
  30 #include "gc_implementation/g1/g1StringDedupQueue.hpp"
  31 #include "runtime/atomic.inline.hpp"
  32 
  33 G1StringDedupThread* G1StringDedupThread::_thread = NULL;
  34 
  35 G1StringDedupThread::G1StringDedupThread() :
  36   ConcurrentGCThread() {
  37   set_name("G1 StrDedup");
  38   create_and_start();
  39 }
  40 
  41 G1StringDedupThread::~G1StringDedupThread() {
  42   ShouldNotReachHere();
  43 }
  44 
  45 void G1StringDedupThread::create() {
  46   assert(G1StringDedup::is_enabled(), "String deduplication not enabled");
  47   assert(_thread == NULL, "One string deduplication thread allowed");
  48   _thread = new G1StringDedupThread();
  49 }
  50 
  51 G1StringDedupThread* G1StringDedupThread::thread() {
  52   assert(G1StringDedup::is_enabled(), "String deduplication not enabled");
  53   assert(_thread != NULL, "String deduplication thread not created");
  54   return _thread;
  55 }
  56 
  57 void G1StringDedupThread::run() {
  58   G1StringDedupStat total_stat;
  59 
  60   initialize_in_thread();
  61   wait_for_universe_init();
  62 
  63   // Main loop
  64   for (;;) {
  65     G1StringDedupStat stat;
  66 
  67     stat.mark_idle();
  68 
  69     // Wait for the queue to become non-empty
  70     G1StringDedupQueue::wait();
  71     if (_should_terminate) {
  72       break;
  73     }
  74 
  75     {
  76       // Include thread in safepoints
  77       SuspendibleThreadSetJoiner sts;
  78 
  79       stat.mark_exec();
  80 
  81       // Process the queue
  82       for (;;) {
  83         oop java_string = G1StringDedupQueue::pop();
  84         if (java_string == NULL) {
  85           break;
  86         }
  87 
  88         G1StringDedupTable::deduplicate(java_string, stat);
  89 
  90         // Safepoint this thread if needed
  91         if (sts.should_yield()) {
  92           stat.mark_block();
  93           sts.yield();
  94           stat.mark_unblock();
  95         }
  96       }
  97 
  98       G1StringDedupTable::trim_entry_cache();
  99 
 100       stat.mark_done();
 101 
 102       // Print statistics
 103       total_stat.add(stat);
 104       print(gclog_or_tty, stat, total_stat);
 105     }
 106   }
 107 
 108   terminate();
 109 }
 110 
 111 void G1StringDedupThread::stop() {
 112   {
 113     MonitorLockerEx ml(Terminator_lock);
 114     _thread->_should_terminate = true;
 115   }
 116 
 117   G1StringDedupQueue::cancel_wait();
 118 
 119   {
 120     MonitorLockerEx ml(Terminator_lock);
 121     while (!_thread->_has_terminated) {
 122       ml.wait();
 123     }
 124   }
 125 }
 126 
 127 void G1StringDedupThread::print(outputStream* st, const G1StringDedupStat& last_stat, const G1StringDedupStat& total_stat) {
 128   if (G1Log::fine() || PrintStringDeduplicationStatistics) {
 129     G1StringDedupStat::print_summary(st, last_stat, total_stat);
 130     if (PrintStringDeduplicationStatistics) {
 131       G1StringDedupStat::print_statistics(st, last_stat, false);
 132       G1StringDedupStat::print_statistics(st, total_stat, true);
 133       G1StringDedupTable::print_statistics(st);
 134       G1StringDedupQueue::print_statistics(st);
 135     }
 136   }
 137 }