1 /*
2 * Copyright (c) 1998, 2020, 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 "logging/log.hpp"
29 #include "runtime/atomic.hpp"
30
31 inline intptr_t ObjectMonitor::is_entered(TRAPS) const {
32 if (THREAD == _owner || THREAD->is_lock_owned((address) _owner)) {
33 return 1;
34 }
35 return 0;
36 }
37
38 inline markWord ObjectMonitor::header() const {
39 return Atomic::load(&_header);
40 }
41
42 inline volatile markWord* ObjectMonitor::header_addr() {
43 assert((intptr_t)this == (intptr_t)&_header, "sync code expects this");
44 return &_header;
45 }
46
47 inline void ObjectMonitor::set_header(markWord hdr) {
48 Atomic::store(&_header, hdr);
49 }
50
51 inline jint ObjectMonitor::waiters() const {
52 return _waiters;
53 }
54
55 // Returns NULL if DEFLATER_MARKER is observed.
56 inline void* ObjectMonitor::owner() const {
57 void* owner = _owner;
58 return owner != DEFLATER_MARKER ? owner : NULL;
59 }
60
61 // Returns true if owner field == DEFLATER_MARKER and false otherwise.
62 // This accessor is called when we really need to know if the owner
63 // field == DEFLATER_MARKER and any non-NULL value won't do the trick.
64 inline bool ObjectMonitor::owner_is_DEFLATER_MARKER() {
65 return Atomic::load(&_owner) == DEFLATER_MARKER;
66 }
67
68 // Returns true if 'this' is being async deflated and false otherwise.
69 inline bool ObjectMonitor::is_being_async_deflated() {
70 return AsyncDeflateIdleMonitors && contentions() < 0;
71 }
72
73 inline void ObjectMonitor::clear() {
74 assert(Atomic::load(&_header).value() != 0, "must be non-zero");
75 assert(_owner == NULL, "must be NULL: owner=" INTPTR_FORMAT, p2i(_owner));
76
77 Atomic::store(&_header, markWord::zero());
78
79 clear_common();
80 }
81
82 inline void ObjectMonitor::clear_common() {
83 if (AsyncDeflateIdleMonitors) {
84 // Async deflation protocol uses the header, owner and contentions
85 // fields. While the ObjectMonitor being deflated is on the global
86 // free list, we leave those three fields alone; contentions < 0
87 // will force any racing threads to retry. The header field is used
88 // by install_displaced_markword_in_object() to restore the object's
89 // header so we cannot check its value here.
90 guarantee(_owner == NULL || _owner == DEFLATER_MARKER,
91 "must be NULL or DEFLATER_MARKER: owner=" INTPTR_FORMAT,
92 p2i(_owner));
93 }
94 assert(contentions() <= 0, "must not be positive: contentions=%d", contentions());
95 assert(_waiters == 0, "must be 0: waiters=%d", _waiters);
96 assert(_recursions == 0, "must be 0: recursions=" INTX_FORMAT, _recursions);
97 assert(_object != NULL, "must be non-NULL");
98
99 set_allocation_state(Free);
100 _object = NULL;
101 }
102
103 inline void* ObjectMonitor::object() const {
104 return _object;
105 }
106
107 inline void* ObjectMonitor::object_addr() {
108 return (void *)(&_object);
109 }
110
111 inline void ObjectMonitor::set_object(void* obj) {
112 _object = obj;
113 }
114
115 // Return number of threads contending for this monitor.
116 inline jint ObjectMonitor::contentions() const {
117 return Atomic::load(&_contentions);
118 }
119
120 // Add value to the contentions field.
121 inline void ObjectMonitor::add_to_contentions(jint value) {
122 Atomic::add(&_contentions, value);
123 }
124
125 // Clear _owner field; current value must match old_value.
126 inline void ObjectMonitor::release_clear_owner(void* old_value) {
127 void* prev = Atomic::load(&_owner);
128 ADIM_guarantee(prev == old_value, "unexpected prev owner=" INTPTR_FORMAT
129 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(old_value));
130 Atomic::release_store(&_owner, (void*)NULL);
131 log_trace(monitorinflation, owner)("release_clear_owner(): mid="
132 INTPTR_FORMAT ", old_value=" INTPTR_FORMAT,
133 p2i(this), p2i(old_value));
134 }
135
136 // Simply set _owner field to new_value; current value must match old_value.
137 // (Simple means no memory sync needed.)
138 inline void ObjectMonitor::set_owner_from(void* old_value, void* new_value) {
139 void* prev = Atomic::load(&_owner);
140 ADIM_guarantee(prev == old_value, "unexpected prev owner=" INTPTR_FORMAT
141 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(old_value));
142 Atomic::store(&_owner, new_value);
143 log_trace(monitorinflation, owner)("set_owner_from(): mid="
144 INTPTR_FORMAT ", old_value=" INTPTR_FORMAT
145 ", new_value=" INTPTR_FORMAT, p2i(this),
146 p2i(old_value), p2i(new_value));
147 }
148
149 // Simply set _owner field to new_value; current value must match old_value1 or old_value2.
150 // (Simple means no memory sync needed.)
151 inline void ObjectMonitor::set_owner_from(void* old_value1, void* old_value2, void* new_value) {
152 void* prev = Atomic::load(&_owner);
153 ADIM_guarantee(prev == old_value1 || prev == old_value2,
154 "unexpected prev owner=" INTPTR_FORMAT ", expected1="
155 INTPTR_FORMAT " or expected2=" INTPTR_FORMAT, p2i(prev),
156 p2i(old_value1), p2i(old_value2));
157 _owner = new_value;
158 log_trace(monitorinflation, owner)("set_owner_from(old1=" INTPTR_FORMAT
159 ", old2=" INTPTR_FORMAT "): mid="
160 INTPTR_FORMAT ", prev=" INTPTR_FORMAT
161 ", new=" INTPTR_FORMAT, p2i(old_value1),
162 p2i(old_value2), p2i(this), p2i(prev),
163 p2i(new_value));
164 }
165
166 // Simply set _owner field to self; current value must match basic_lock_p.
167 inline void ObjectMonitor::set_owner_from_BasicLock(void* basic_lock_p, Thread* self) {
168 void* prev = Atomic::load(&_owner);
169 ADIM_guarantee(prev == basic_lock_p, "unexpected prev owner=" INTPTR_FORMAT
170 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(basic_lock_p));
171 // Non-null owner field to non-null owner field is safe without
172 // cmpxchg() as long as all readers can tolerate either flavor.
173 Atomic::store(&_owner, self);
174 log_trace(monitorinflation, owner)("set_owner_from_BasicLock(): mid="
175 INTPTR_FORMAT ", basic_lock_p="
176 INTPTR_FORMAT ", new_value=" INTPTR_FORMAT,
177 p2i(this), p2i(basic_lock_p), p2i(self));
178 }
179
180 // Try to set _owner field to new_value if the current value matches
181 // old_value. Otherwise, does not change the _owner field. Returns
182 // the prior value of the _owner field.
183 inline void* ObjectMonitor::try_set_owner_from(void* old_value, void* new_value) {
184 void* prev = Atomic::cmpxchg(&_owner, old_value, new_value);
185 if (prev == old_value) {
186 log_trace(monitorinflation, owner)("try_set_owner_from(): mid="
187 INTPTR_FORMAT ", prev=" INTPTR_FORMAT
188 ", new=" INTPTR_FORMAT, p2i(this),
189 p2i(prev), p2i(new_value));
190 }
191 return prev;
192 }
193
194 inline void ObjectMonitor::set_allocation_state(ObjectMonitor::AllocationState s) {
195 _allocation_state = s;
196 }
197
198 inline ObjectMonitor::AllocationState ObjectMonitor::allocation_state() const {
199 return _allocation_state;
200 }
201
202 inline bool ObjectMonitor::is_free() const {
203 return _allocation_state == Free;
204 }
205
206 inline bool ObjectMonitor::is_old() const {
207 return _allocation_state == Old;
208 }
209
210 inline bool ObjectMonitor::is_new() const {
211 return _allocation_state == New;
212 }
213
214 // The _next_om field can be concurrently read and modified so we
215 // use Atomic operations to disable compiler optimizations that
216 // might try to elide loading and/or storing this field.
217
218 inline ObjectMonitor* ObjectMonitor::next_om() const {
219 return Atomic::load(&_next_om);
220 }
221
222 // Simply set _next_om field to new_value.
223 inline void ObjectMonitor::set_next_om(ObjectMonitor* new_value) {
224 Atomic::store(&_next_om, new_value);
225 }
226
227 // Try to set _next_om field to new_value if the current value matches
228 // old_value. Otherwise, does not change the _next_om field. Returns
229 // the prior value of the _next_om field.
230 inline ObjectMonitor* ObjectMonitor::try_set_next_om(ObjectMonitor* old_value, ObjectMonitor* new_value) {
231 return Atomic::cmpxchg(&_next_om, old_value, new_value);
232 }
233
234 #endif // SHARE_RUNTIME_OBJECTMONITOR_INLINE_HPP