1 /*
2 * Copyright (c) 1998, 2024, 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/lockStack.inline.hpp"
34 #include "runtime/synchronizer.hpp"
35
36 inline bool ObjectMonitor::is_entered(JavaThread* current) const {
37 if (LockingMode == LM_LIGHTWEIGHT) {
38 if (is_owner_anonymous()) {
39 return current->lock_stack().contains(object());
40 } else {
41 return current == owner_raw();
42 }
43 } else {
44 void* owner = owner_raw();
45 if (current == owner || current->is_lock_owned((address)owner)) {
46 return true;
47 }
48 }
49 return false;
50 }
51
52 inline markWord ObjectMonitor::header() const {
53 return Atomic::load(&_header);
54 }
55
56 inline volatile markWord* ObjectMonitor::header_addr() {
57 return &_header;
58 }
59
60 inline void ObjectMonitor::set_header(markWord hdr) {
61 Atomic::store(&_header, hdr);
62 }
63
64 inline int ObjectMonitor::waiters() const {
65 return _waiters;
66 }
67
68 inline bool ObjectMonitor::has_owner() const {
69 void* owner = owner_raw();
70 return owner != nullptr && owner != DEFLATER_MARKER;
71 }
72
73 // Returns null if DEFLATER_MARKER is observed.
74 inline void* ObjectMonitor::owner() const {
75 void* owner = owner_raw();
76 return owner != DEFLATER_MARKER ? owner : nullptr;
77 }
78
79 inline void* ObjectMonitor::owner_raw() const {
80 return Atomic::load(&_owner);
81 }
82
83 // Returns true if owner field == DEFLATER_MARKER and false otherwise.
84 // This accessor is called when we really need to know if the owner
85 // field == DEFLATER_MARKER and any non-null value won't do the trick.
86 inline bool ObjectMonitor::owner_is_DEFLATER_MARKER() const {
87 return owner_raw() == DEFLATER_MARKER;
88 }
89
90 // Returns true if 'this' is being async deflated and false otherwise.
91 inline bool ObjectMonitor::is_being_async_deflated() {
92 return contentions() < 0;
93 }
94
95 // Return number of threads contending for this monitor.
96 inline int ObjectMonitor::contentions() const {
97 return Atomic::load(&_contentions);
98 }
99
100 // Add value to the contentions field.
101 inline void ObjectMonitor::add_to_contentions(int value) {
102 Atomic::add(&_contentions, value);
103 }
104
105 inline void ObjectMonitor::set_recursions(size_t recursions) {
106 assert(_recursions == 0, "must be");
107 assert(has_owner(), "must be owned");
108 _recursions = checked_cast<intx>(recursions);
109 }
110
111 // Clear _owner field; current value must match old_value.
112 inline void ObjectMonitor::release_clear_owner(void* old_value) {
113 #ifdef ASSERT
114 void* prev = Atomic::load(&_owner);
115 assert(prev == old_value, "unexpected prev owner=" INTPTR_FORMAT
116 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(old_value));
117 #endif
118 Atomic::release_store(&_owner, (void*)nullptr);
119 log_trace(monitorinflation, owner)("release_clear_owner(): mid="
120 INTPTR_FORMAT ", old_value=" INTPTR_FORMAT,
121 p2i(this), p2i(old_value));
122 }
123
124 // Simply set _owner field to new_value; current value must match old_value.
125 // (Simple means no memory sync needed.)
126 inline void ObjectMonitor::set_owner_from(void* old_value, void* new_value) {
127 #ifdef ASSERT
128 void* prev = Atomic::load(&_owner);
129 assert(prev == old_value, "unexpected prev owner=" INTPTR_FORMAT
130 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(old_value));
131 #endif
132 Atomic::store(&_owner, new_value);
133 log_trace(monitorinflation, owner)("set_owner_from(): mid="
134 INTPTR_FORMAT ", old_value=" INTPTR_FORMAT
135 ", new_value=" INTPTR_FORMAT, p2i(this),
136 p2i(old_value), p2i(new_value));
137 }
138
139 // Simply set _owner field to self; current value must match basic_lock_p.
140 inline void ObjectMonitor::set_owner_from_BasicLock(void* basic_lock_p, JavaThread* current) {
141 #ifdef ASSERT
142 void* prev = Atomic::load(&_owner);
143 assert(prev == basic_lock_p, "unexpected prev owner=" INTPTR_FORMAT
144 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(basic_lock_p));
145 #endif
146 // Non-null owner field to non-null owner field is safe without
147 // cmpxchg() as long as all readers can tolerate either flavor.
148 Atomic::store(&_owner, current);
149 log_trace(monitorinflation, owner)("set_owner_from_BasicLock(): mid="
150 INTPTR_FORMAT ", basic_lock_p="
151 INTPTR_FORMAT ", new_value=" INTPTR_FORMAT,
152 p2i(this), p2i(basic_lock_p), p2i(current));
153 }
154
155 // Try to set _owner field to new_value if the current value matches
156 // old_value. Otherwise, does not change the _owner field. Returns
157 // the prior value of the _owner field.
158 inline void* ObjectMonitor::try_set_owner_from(void* old_value, void* new_value) {
159 void* prev = Atomic::cmpxchg(&_owner, old_value, new_value);
160 if (prev == old_value) {
161 log_trace(monitorinflation, owner)("try_set_owner_from(): mid="
162 INTPTR_FORMAT ", prev=" INTPTR_FORMAT
163 ", new=" INTPTR_FORMAT, p2i(this),
164 p2i(prev), p2i(new_value));
165 }
166 return prev;
167 }
168
169 // The _next_om field can be concurrently read and modified so we
170 // use Atomic operations to disable compiler optimizations that
171 // might try to elide loading and/or storing this field.
172
173 // Simply get _next_om field.
174 inline ObjectMonitor* ObjectMonitor::next_om() const {
175 return Atomic::load(&_next_om);
176 }
177
178 // Simply set _next_om field to new_value.
179 inline void ObjectMonitor::set_next_om(ObjectMonitor* new_value) {
180 Atomic::store(&_next_om, new_value);
181 }
182
183 #endif // SHARE_RUNTIME_OBJECTMONITOR_INLINE_HPP