< prev index next >

src/share/vm/gc/g1/g1StringDedup.cpp

Print this page
rev 10297 : [mq]: webrev.01
   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  *


  30 #include "gc/g1/g1StringDedupQueue.hpp"
  31 #include "gc/g1/g1StringDedupStat.hpp"
  32 #include "gc/g1/g1StringDedupTable.hpp"
  33 #include "gc/g1/g1StringDedupThread.hpp"
  34 #include "runtime/atomic.inline.hpp"
  35 
  36 bool G1StringDedup::_enabled = false;
  37 
  38 void G1StringDedup::initialize() {
  39   assert(UseG1GC, "String deduplication only available with G1");
  40   if (UseStringDeduplication) {
  41     _enabled = true;
  42     G1StringDedupQueue::create();
  43     G1StringDedupTable::create();
  44     G1StringDedupThread::create();
  45   }
  46 }
  47 
  48 void G1StringDedup::stop() {
  49   assert(is_enabled(), "String deduplication not enabled");
  50   G1StringDedupThread::stop();
  51 }
  52 
  53 bool G1StringDedup::is_candidate_from_mark(oop obj) {
  54   if (java_lang_String::is_instance_inlined(obj)) {
  55     bool from_young = G1CollectedHeap::heap()->heap_region_containing(obj)->is_young();
  56     if (from_young && obj->age() < StringDeduplicationAgeThreshold) {
  57       // Candidate found. String is being evacuated from young to old but has not
  58       // reached the deduplication age threshold, i.e. has not previously been a
  59       // candidate during its life in the young generation.
  60       return true;
  61     }
  62   }
  63 
  64   // Not a candidate
  65   return false;
  66 }
  67 
  68 void G1StringDedup::enqueue_from_mark(oop java_string) {
  69   assert(is_enabled(), "String deduplication not enabled");
  70   if (is_candidate_from_mark(java_string)) {


   1 /*
   2  * Copyright (c) 2014, 2016, 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  *


  30 #include "gc/g1/g1StringDedupQueue.hpp"
  31 #include "gc/g1/g1StringDedupStat.hpp"
  32 #include "gc/g1/g1StringDedupTable.hpp"
  33 #include "gc/g1/g1StringDedupThread.hpp"
  34 #include "runtime/atomic.inline.hpp"
  35 
  36 bool G1StringDedup::_enabled = false;
  37 
  38 void G1StringDedup::initialize() {
  39   assert(UseG1GC, "String deduplication only available with G1");
  40   if (UseStringDeduplication) {
  41     _enabled = true;
  42     G1StringDedupQueue::create();
  43     G1StringDedupTable::create();
  44     G1StringDedupThread::create();
  45   }
  46 }
  47 
  48 void G1StringDedup::stop() {
  49   assert(is_enabled(), "String deduplication not enabled");
  50   G1StringDedupThread::thread()->stop();
  51 }
  52 
  53 bool G1StringDedup::is_candidate_from_mark(oop obj) {
  54   if (java_lang_String::is_instance_inlined(obj)) {
  55     bool from_young = G1CollectedHeap::heap()->heap_region_containing(obj)->is_young();
  56     if (from_young && obj->age() < StringDeduplicationAgeThreshold) {
  57       // Candidate found. String is being evacuated from young to old but has not
  58       // reached the deduplication age threshold, i.e. has not previously been a
  59       // candidate during its life in the young generation.
  60       return true;
  61     }
  62   }
  63 
  64   // Not a candidate
  65   return false;
  66 }
  67 
  68 void G1StringDedup::enqueue_from_mark(oop java_string) {
  69   assert(is_enabled(), "String deduplication not enabled");
  70   if (is_candidate_from_mark(java_string)) {


< prev index next >