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)) {
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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)) {
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