1 /*
2 * Copyright (c) 1998, 2021, 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 #ifndef SHARE_RUNTIME_OBJECTMONITOR_INLINE_HPP
26 #define SHARE_RUNTIME_OBJECTMONITOR_INLINE_HPP
27
28 #include "runtime/objectMonitor.hpp"
29
30 #include "logging/log.hpp"
31 #include "oops/access.inline.hpp"
32 #include "runtime/atomic.hpp"
33 #include "runtime/synchronizer.hpp"
34
35 inline intptr_t ObjectMonitor::is_entered(JavaThread* current) const {
36 void* owner = owner_raw();
37 if (current == owner || current->is_lock_owned((address)owner)) {
38 return 1;
39 }
40 return 0;
41 }
42
43 inline markWord ObjectMonitor::header() const {
44 return Atomic::load(&_header);
45 }
46
47 inline volatile markWord* ObjectMonitor::header_addr() {
48 return &_header;
49 }
50
51 inline void ObjectMonitor::set_header(markWord hdr) {
52 Atomic::store(&_header, hdr);
53 }
54
55 inline jint ObjectMonitor::waiters() const {
56 return _waiters;
57 }
58
59 // Returns NULL if DEFLATER_MARKER is observed.
60 inline void* ObjectMonitor::owner() const {
61 void* owner = owner_raw();
62 return owner != DEFLATER_MARKER ? owner : NULL;
63 }
64
65 inline void* ObjectMonitor::owner_raw() const {
66 return Atomic::load(&_owner);
67 }
68
69 // Returns true if owner field == DEFLATER_MARKER and false otherwise.
70 // This accessor is called when we really need to know if the owner
71 // field == DEFLATER_MARKER and any non-NULL value won't do the trick.
72 inline bool ObjectMonitor::owner_is_DEFLATER_MARKER() const {
73 return owner_raw() == DEFLATER_MARKER;
74 }
75
76 // Returns true if 'this' is being async deflated and false otherwise.
77 inline bool ObjectMonitor::is_being_async_deflated() {
78 return contentions() < 0;
79 }
80
81 // Return number of threads contending for this monitor.
82 inline jint ObjectMonitor::contentions() const {
83 return Atomic::load(&_contentions);
84 }
85
86 // Add value to the contentions field.
87 inline void ObjectMonitor::add_to_contentions(jint value) {
88 Atomic::add(&_contentions, value);
89 }
90
91 // Clear _owner field; current value must match old_value.
92 inline void ObjectMonitor::release_clear_owner(void* old_value) {
93 #ifdef ASSERT
94 void* prev = Atomic::load(&_owner);
95 assert(prev == old_value, "unexpected prev owner=" INTPTR_FORMAT
96 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(old_value));
97 #endif
98 Atomic::release_store(&_owner, (void*)NULL);
99 log_trace(monitorinflation, owner)("release_clear_owner(): mid="
100 INTPTR_FORMAT ", old_value=" INTPTR_FORMAT,
101 p2i(this), p2i(old_value));
102 }
103
104 // Simply set _owner field to new_value; current value must match old_value.
105 // (Simple means no memory sync needed.)
106 inline void ObjectMonitor::set_owner_from(void* old_value, void* new_value) {
107 #ifdef ASSERT
108 void* prev = Atomic::load(&_owner);
109 assert(prev == old_value, "unexpected prev owner=" INTPTR_FORMAT
110 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(old_value));
111 #endif
112 Atomic::store(&_owner, new_value);
113 log_trace(monitorinflation, owner)("set_owner_from(): mid="
114 INTPTR_FORMAT ", old_value=" INTPTR_FORMAT
115 ", new_value=" INTPTR_FORMAT, p2i(this),
116 p2i(old_value), p2i(new_value));
117 }
118
119 // Simply set _owner field to self; current value must match basic_lock_p.
120 inline void ObjectMonitor::set_owner_from_BasicLock(void* basic_lock_p, JavaThread* current) {
121 #ifdef ASSERT
122 void* prev = Atomic::load(&_owner);
123 assert(prev == basic_lock_p, "unexpected prev owner=" INTPTR_FORMAT
124 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(basic_lock_p));
125 #endif
126 // Non-null owner field to non-null owner field is safe without
127 // cmpxchg() as long as all readers can tolerate either flavor.
128 Atomic::store(&_owner, current);
129 log_trace(monitorinflation, owner)("set_owner_from_BasicLock(): mid="
130 INTPTR_FORMAT ", basic_lock_p="
131 INTPTR_FORMAT ", new_value=" INTPTR_FORMAT,
132 p2i(this), p2i(basic_lock_p), p2i(current));
133 }
134
135 // Try to set _owner field to new_value if the current value matches
136 // old_value. Otherwise, does not change the _owner field. Returns
137 // the prior value of the _owner field.
138 inline void* ObjectMonitor::try_set_owner_from(void* old_value, void* new_value) {
139 void* prev = Atomic::cmpxchg(&_owner, old_value, new_value);
140 if (prev == old_value) {
141 log_trace(monitorinflation, owner)("try_set_owner_from(): mid="
142 INTPTR_FORMAT ", prev=" INTPTR_FORMAT
143 ", new=" INTPTR_FORMAT, p2i(this),
144 p2i(prev), p2i(new_value));
145 }
146 return prev;
147 }
148
149 // The _next_om field can be concurrently read and modified so we
150 // use Atomic operations to disable compiler optimizations that
151 // might try to elide loading and/or storing this field.
152
153 // Simply get _next_om field.
154 inline ObjectMonitor* ObjectMonitor::next_om() const {
155 return Atomic::load(&_next_om);
156 }
157
158 // Get _next_om field with acquire semantics.
159 inline ObjectMonitor* ObjectMonitor::next_om_acquire() const {
160 return Atomic::load_acquire(&_next_om);
161 }
162
163 // Simply set _next_om field to new_value.
164 inline void ObjectMonitor::set_next_om(ObjectMonitor* new_value) {
165 Atomic::store(&_next_om, new_value);
166 }
167
168 // Set _next_om field to new_value with release semantics.
169 inline void ObjectMonitor::release_set_next_om(ObjectMonitor* new_value) {
170 Atomic::release_store(&_next_om, new_value);
171 }
172
173 // Try to set _next_om field to new_value if the current value matches
174 // old_value. Otherwise, does not change the _next_om field. Returns
175 // the prior value of the _next_om field.
176 inline ObjectMonitor* ObjectMonitor::try_set_next_om(ObjectMonitor* old_value, ObjectMonitor* new_value) {
177 return Atomic::cmpxchg(&_next_om, old_value, new_value);
178 }
179
180 #endif // SHARE_RUNTIME_OBJECTMONITOR_INLINE_HPP