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 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 // Async deflation protocol uses the header, owner and contentions
84 // fields. While the ObjectMonitor being deflated is on the global
85 // free list, we leave those three fields alone; contentions < 0
86 // will force any racing threads to retry. The header field is used
87 // by install_displaced_markword_in_object() to restore the object's
88 // header so we cannot check its value here.
89 guarantee(_owner == NULL || _owner == DEFLATER_MARKER,
90 "must be NULL or DEFLATER_MARKER: owner=" INTPTR_FORMAT,
91 p2i(_owner));
92 assert(contentions() <= 0, "must not be positive: contentions=%d", contentions());
93 assert(_waiters == 0, "must be 0: waiters=%d", _waiters);
94 assert(_recursions == 0, "must be 0: recursions=" INTX_FORMAT, _recursions);
95 assert(_object != NULL, "must be non-NULL");
96
97 set_allocation_state(Free);
98 _object = NULL;
99 }
100
101 inline void* ObjectMonitor::object() const {
102 return _object;
103 }
104
105 inline void* ObjectMonitor::object_addr() {
106 return (void *)(&_object);
107 }
108
109 inline void ObjectMonitor::set_object(void* obj) {
110 _object = obj;
111 }
112
113 // Return number of threads contending for this monitor.
114 inline jint ObjectMonitor::contentions() const {
115 return Atomic::load(&_contentions);
116 }
117
118 // Add value to the contentions field.
119 inline void ObjectMonitor::add_to_contentions(jint value) {
120 Atomic::add(&_contentions, value);
121 }
122
123 // Clear _owner field; current value must match old_value.
124 inline void ObjectMonitor::release_clear_owner(void* old_value) {
125 #ifdef ASSERT
126 void* prev = Atomic::load(&_owner);
127 #endif
128 assert(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 #ifdef ASSERT
140 void* prev = Atomic::load(&_owner);
141 #endif
142 assert(prev == old_value, "unexpected prev owner=" INTPTR_FORMAT
143 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(old_value));
144 Atomic::store(&_owner, new_value);
145 log_trace(monitorinflation, owner)("set_owner_from(): mid="
146 INTPTR_FORMAT ", old_value=" INTPTR_FORMAT
147 ", new_value=" INTPTR_FORMAT, p2i(this),
148 p2i(old_value), p2i(new_value));
149 }
150
151 // Simply set _owner field to new_value; current value must match old_value1 or old_value2.
152 // (Simple means no memory sync needed.)
153 inline void ObjectMonitor::set_owner_from(void* old_value1, void* old_value2, void* new_value) {
154 void* prev = Atomic::load(&_owner);
155 assert(prev == old_value1 || prev == old_value2,
156 "unexpected prev owner=" INTPTR_FORMAT ", expected1="
157 INTPTR_FORMAT " or expected2=" INTPTR_FORMAT, p2i(prev),
158 p2i(old_value1), p2i(old_value2));
159 _owner = new_value;
160 log_trace(monitorinflation, owner)("set_owner_from(old1=" INTPTR_FORMAT
161 ", old2=" INTPTR_FORMAT "): mid="
162 INTPTR_FORMAT ", prev=" INTPTR_FORMAT
163 ", new=" INTPTR_FORMAT, p2i(old_value1),
164 p2i(old_value2), p2i(this), p2i(prev),
165 p2i(new_value));
166 }
167
168 // Simply set _owner field to self; current value must match basic_lock_p.
169 inline void ObjectMonitor::set_owner_from_BasicLock(void* basic_lock_p, Thread* self) {
170 #ifdef ASSERT
171 void* prev = Atomic::load(&_owner);
172 #endif
173 assert(prev == basic_lock_p, "unexpected prev owner=" INTPTR_FORMAT
174 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(basic_lock_p));
175 // Non-null owner field to non-null owner field is safe without
176 // cmpxchg() as long as all readers can tolerate either flavor.
177 Atomic::store(&_owner, self);
178 log_trace(monitorinflation, owner)("set_owner_from_BasicLock(): mid="
179 INTPTR_FORMAT ", basic_lock_p="
180 INTPTR_FORMAT ", new_value=" INTPTR_FORMAT,
181 p2i(this), p2i(basic_lock_p), p2i(self));
182 }
183
184 // Try to set _owner field to new_value if the current value matches
185 // old_value. Otherwise, does not change the _owner field. Returns
186 // the prior value of the _owner field.
187 inline void* ObjectMonitor::try_set_owner_from(void* old_value, void* new_value) {
188 void* prev = Atomic::cmpxchg(&_owner, old_value, new_value);
189 if (prev == old_value) {
190 log_trace(monitorinflation, owner)("try_set_owner_from(): mid="
191 INTPTR_FORMAT ", prev=" INTPTR_FORMAT
192 ", new=" INTPTR_FORMAT, p2i(this),
193 p2i(prev), p2i(new_value));
194 }
195 return prev;
196 }
197
198 inline void ObjectMonitor::set_allocation_state(ObjectMonitor::AllocationState s) {
199 _allocation_state = s;
200 }
201
202 inline ObjectMonitor::AllocationState ObjectMonitor::allocation_state() const {
203 return _allocation_state;
204 }
205
206 inline bool ObjectMonitor::is_free() const {
207 return _allocation_state == Free;
208 }
209
210 inline bool ObjectMonitor::is_old() const {
211 return _allocation_state == Old;
212 }
213
214 inline bool ObjectMonitor::is_new() const {
215 return _allocation_state == New;
216 }
217
218 // The _next_om field can be concurrently read and modified so we
219 // use Atomic operations to disable compiler optimizations that
220 // might try to elide loading and/or storing this field.
221
222 inline ObjectMonitor* ObjectMonitor::next_om() const {
223 return Atomic::load(&_next_om);
224 }
225
226 // Simply set _next_om field to new_value.
227 inline void ObjectMonitor::set_next_om(ObjectMonitor* new_value) {
228 Atomic::store(&_next_om, new_value);
229 }
230
231 // Try to set _next_om field to new_value if the current value matches
232 // old_value. Otherwise, does not change the _next_om field. Returns
233 // the prior value of the _next_om field.
234 inline ObjectMonitor* ObjectMonitor::try_set_next_om(ObjectMonitor* old_value, ObjectMonitor* new_value) {
235 return Atomic::cmpxchg(&_next_om, old_value, new_value);
236 }
237
238 #endif // SHARE_RUNTIME_OBJECTMONITOR_INLINE_HPP