1 /*
   2  * Copyright (c) 2014, 2018, 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/shared/stringdedup/stringDedup.hpp"
  28 #include "gc/shared/stringdedup/stringDedupQueue.hpp"
  29 #include "gc/shared/stringdedup/stringDedupQueue.inline.hpp"
  30 #include "gc/shared/stringdedup/stringDedupTable.hpp"
  31 #include "gc/shared/stringdedup/stringDedupThread.hpp"
  32 #include "gc/shared/suspendibleThreadSet.hpp"
  33 #include "logging/log.hpp"
  34 #include "oops/access.inline.hpp"
  35 #include "oops/oop.inline.hpp"
  36 #include "runtime/atomic.hpp"
  37 
  38 StringDedupThread* StringDedupThread::_thread = NULL;
  39 
  40 StringDedupThread::StringDedupThread() :
  41   ConcurrentGCThread() {
  42   set_name("StrDedup");
  43   create_and_start();
  44 }
  45 
  46 StringDedupThread::~StringDedupThread() {
  47   ShouldNotReachHere();
  48 }
  49 
  50 StringDedupThread* StringDedupThread::thread() {
  51   assert(_thread != NULL, "String deduplication thread not created");
  52   return _thread;
  53 }
  54 
  55 class StringDedupSharedClosure: public OopClosure {
  56  private:
  57   StringDedupStat* _stat;
  58 
  59  public:
  60   StringDedupSharedClosure(StringDedupStat* stat) : _stat(stat) {}
  61 
  62   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
  63   virtual void do_oop(oop* p) {
  64     oop java_string = RawAccess<>::oop_load(p);
  65     StringDedupTable::deduplicate(java_string, _stat);
  66   }
  67 };
  68 
  69 // The CDS archive does not include the string dedupication table. Only the string
  70 // table is saved in the archive. The shared strings from CDS archive need to be
  71 // added to the string dedupication table before deduplication occurs. That is
  72 // done in the begining of the StringDedupThread (see StringDedupThread::do_deduplication()).
  73 void StringDedupThread::deduplicate_shared_strings(StringDedupStat* stat) {
  74   StringDedupSharedClosure sharedStringDedup(stat);
  75   StringTable::shared_oops_do(&sharedStringDedup);
  76 }
  77 
  78 void StringDedupThread::pre_run() {
  79   SuspendibleThreadSetJoiner sts_join;
  80   ConcurrentGCThread::pre_run();
  81 }
  82 
  83 void StringDedupThread::post_run() {
  84   SuspendibleThreadSetJoiner sts_join;
  85   ConcurrentGCThread::post_run();
  86 }
  87 
  88 void StringDedupThread::stop_service() {
  89   StringDedupQueue::cancel_wait();
  90 }
  91 
  92 void StringDedupThread::print_start(const StringDedupStat* last_stat) {
  93   StringDedupStat::print_start(last_stat);
  94 }
  95 
  96 void StringDedupThread::print_end(const StringDedupStat* last_stat, const StringDedupStat* total_stat) {
  97   StringDedupStat::print_end(last_stat, total_stat);
  98   if (log_is_enabled(Debug, gc, stringdedup)) {
  99     last_stat->print_statistics(false);
 100     total_stat->print_statistics(true);
 101 
 102     StringDedupTable::print_statistics();
 103     StringDedupQueue::print_statistics();
 104   }
 105 }