1 /*
2 * Copyright (c) 2017, 2020, Red Hat, Inc. 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 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHSTRDEDUPQUEUE_INLINE_HPP
26 #define SHARE_GC_SHENANDOAH_SHENANDOAHSTRDEDUPQUEUE_INLINE_HPP
27
28 #include "gc/shenandoah/shenandoahStrDedupQueue.hpp"
29 #include "oops/access.hpp"
30 #include "runtime/atomic.hpp"
31
32 // With concurrent string dedup cleaning up, GC worker threads
33 // may see oops just enqueued, so release_store and load_acquire
34 // relationship needs to be established between enqueuing threads
35 // and GC workers.
36 // For example, when GC sees a slot (index), there must be a valid
37 // (dead or live) oop.
38 // Note: There is no concern if GC misses newly enqueued oops,
39 // since LRB ensures they are in to-space.
40 template <uint buffer_size>
ShenandoahOopBuffer()41 ShenandoahOopBuffer<buffer_size>::ShenandoahOopBuffer() :
42 _index(0), _next(NULL) {
43 }
44
45 template <uint buffer_size>
is_full() const46 bool ShenandoahOopBuffer<buffer_size>::is_full() const {
47 return index_acquire() >= buffer_size;
48 }
49
50 template <uint buffer_size>
is_empty() const51 bool ShenandoahOopBuffer<buffer_size>::is_empty() const {
52 return index_acquire() == 0;
53 }
54
55 template <uint buffer_size>
size() const56 uint ShenandoahOopBuffer<buffer_size>::size() const {
57 return index_acquire();
58 }
59
60 template <uint buffer_size>
push(oop obj)61 void ShenandoahOopBuffer<buffer_size>::push(oop obj) {
62 assert(!is_full(), "Buffer is full");
63 uint idx = index_acquire();
64 RawAccess<IS_NOT_NULL>::oop_store(&_buf[idx], obj);
65 set_index_release(idx + 1);
66 }
67
68 template <uint buffer_size>
pop()69 oop ShenandoahOopBuffer<buffer_size>::pop() {
70 assert(!is_empty(), "Buffer is empty");
71 uint idx = index_acquire() - 1;
72 oop value = NativeAccess<ON_PHANTOM_OOP_REF | AS_NO_KEEPALIVE | MO_ACQUIRE>::oop_load(&_buf[idx]);
73 set_index_release(idx);
74 return value;
75 }
76
77 template <uint buffer_size>
set_next(ShenandoahOopBuffer<buffer_size> * next)78 void ShenandoahOopBuffer<buffer_size>::set_next(ShenandoahOopBuffer<buffer_size>* next) {
79 _next = next;
80 }
81
82 template <uint buffer_size>
next() const83 ShenandoahOopBuffer<buffer_size>* ShenandoahOopBuffer<buffer_size>::next() const {
84 return _next;
85 }
86
87 template <uint buffer_size>
reset()88 void ShenandoahOopBuffer<buffer_size>::reset() {
89 _index = 0;
90 _next = NULL;
91 }
92
93 template <uint buffer_size>
index_acquire() const94 uint ShenandoahOopBuffer<buffer_size>::index_acquire() const {
95 return Atomic::load_acquire(&_index);
96 }
97
98 template <uint buffer_size>
set_index_release(uint index)99 void ShenandoahOopBuffer<buffer_size>::set_index_release(uint index) {
100 return Atomic::release_store(&_index, index);
101 }
102
103 template <uint buffer_size>
unlink_or_oops_do(StringDedupUnlinkOrOopsDoClosure * cl)104 void ShenandoahOopBuffer<buffer_size>::unlink_or_oops_do(StringDedupUnlinkOrOopsDoClosure* cl) {
105 uint len = size();
106 for (uint index = 0; index < len; index ++) {
107 oop* obj_addr = &_buf[index];
108 if (*obj_addr != NULL) {
109 if (cl->is_alive(*obj_addr)) {
110 cl->keep_alive(obj_addr);
111 } else {
112 RawAccess<MO_RELEASE>::oop_store(&_buf[index], oop());
113 }
114 }
115 }
116 }
117
118 template <uint buffer_size>
oops_do(OopClosure * cl)119 void ShenandoahOopBuffer<buffer_size>::oops_do(OopClosure* cl) {
120 uint len = size();
121 for (uint index = 0; index < len; index ++) {
122 cl->do_oop(&_buf[index]);
123 }
124 }
125
126 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHSTRDEDUPQUEUE_INLINE_HPP
127