1 /*
2 * Copyright (c) 1998, 2019, 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 _owner == DEFLATER_MARKER;
66 }
67
68 inline void ObjectMonitor::clear() {
69 assert(Atomic::load(&_header).value() != 0, "must be non-zero");
70 assert(_owner == NULL, "must be NULL: owner=" INTPTR_FORMAT, p2i(_owner));
71 #ifdef ASSERT
72 jint l_ref_count = ref_count();
73 #endif
74 assert(l_ref_count == 0, "must be 0: l_ref_count=%d, ref_count=%d", l_ref_count, ref_count());
75
76 Atomic::store(&_header, markWord::zero());
77
78 clear_using_JT();
79 }
80
81 inline void ObjectMonitor::clear_using_JT() {
82 // Unlike other *_using_JT() functions, we cannot assert
83 // AsyncDeflateIdleMonitors or Thread::current()->is_Java_thread()
84 // because clear() calls this function for the rest of its checks.
85
86 if (AsyncDeflateIdleMonitors) {
87 // Async deflation protocol uses the header, owner and ref_count
88 // fields. While the ObjectMonitor being deflated is on the global free
89 // list, we leave those three fields alone; owner == DEFLATER_MARKER
90 // and ref_count < 0 will force any racing threads to retry. The
91 // header field is used by install_displaced_markword_in_object()
92 // in the last part of the deflation protocol so we cannot check
93 // its value here.
94 guarantee(_owner == NULL || _owner == DEFLATER_MARKER,
95 "must be NULL or DEFLATER_MARKER: owner=" INTPTR_FORMAT,
96 p2i(_owner));
97 jint l_ref_count = ref_count();
98 guarantee(l_ref_count <= 0, "must be <= 0: l_ref_count=%d, ref_count=%d", l_ref_count, ref_count());
99 }
100 assert(_contentions == 0, "must be 0: contentions=%d", _contentions);
101 assert(_waiters == 0, "must be 0: waiters=%d", _waiters);
102 assert(_recursions == 0, "must be 0: recursions=" INTX_FORMAT, _recursions);
103 assert(_object != NULL, "must be non-NULL");
104
105 set_allocation_state(Free);
106 _object = NULL;
107 }
108
109 inline void* ObjectMonitor::object() const {
110 return _object;
111 }
112
113 inline void* ObjectMonitor::object_addr() {
114 return (void *)(&_object);
115 }
116
117 inline void ObjectMonitor::set_object(void* obj) {
118 _object = obj;
119 }
120
121 // return number of threads contending for this monitor
122 inline jint ObjectMonitor::contentions() const {
123 return _contentions;
124 }
125
126 // Clear _owner field; current value must match old_value.
127 inline void ObjectMonitor::release_clear_owner(void* old_value) {
128 void* prev = Atomic::load(&_owner);
129 ADIM_guarantee(prev == old_value, "unexpected prev owner=" INTPTR_FORMAT
130 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(old_value));
131 Atomic::release_store(&_owner, (void*)NULL);
132 log_trace(monitorinflation, owner)("release_clear_owner(): mid="
133 INTPTR_FORMAT ", old_value=" INTPTR_FORMAT,
134 p2i(this), p2i(old_value));
135 }
136
137 // Simply set _owner field to new_value; current value must match old_value.
138 // (Simple means no memory sync needed.)
139 inline void ObjectMonitor::set_owner_from(void* old_value, void* new_value) {
140 void* prev = Atomic::load(&_owner);
141 ADIM_guarantee(prev == old_value, "unexpected prev owner=" INTPTR_FORMAT
142 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(old_value));
143 Atomic::store(&_owner, new_value);
144 log_trace(monitorinflation, owner)("set_owner_from(): mid="
145 INTPTR_FORMAT ", old_value=" INTPTR_FORMAT
146 ", new_value=" INTPTR_FORMAT, p2i(this),
147 p2i(old_value), p2i(new_value));
148 }
149
150 // Simply set _owner field to new_value; current value must match old_value1 or old_value2.
151 // (Simple means no memory sync needed.)
152 inline void ObjectMonitor::set_owner_from(void* old_value1, void* old_value2, void* new_value) {
153 void* prev = Atomic::load(&_owner);
154 ADIM_guarantee(prev == old_value1 || prev == old_value2,
155 "unexpected prev owner=" INTPTR_FORMAT ", expected1="
156 INTPTR_FORMAT " or expected2=" INTPTR_FORMAT, p2i(prev),
157 p2i(old_value1), p2i(old_value2));
158 _owner = new_value;
159 log_trace(monitorinflation, owner)("set_owner_from(old1=" INTPTR_FORMAT
160 ", old2=" INTPTR_FORMAT "): mid="
161 INTPTR_FORMAT ", prev=" INTPTR_FORMAT
162 ", new=" INTPTR_FORMAT, p2i(old_value1),
163 p2i(old_value2), p2i(this), p2i(prev),
164 p2i(new_value));
165 }
166
167 // Simply set _owner field to self; current value must match basic_lock_p.
168 inline void ObjectMonitor::set_owner_from_BasicLock(void* basic_lock_p, Thread* self) {
169 void* prev = Atomic::load(&_owner);
170 ADIM_guarantee(prev == basic_lock_p, "unexpected prev owner=" INTPTR_FORMAT
171 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(basic_lock_p));
172 // Non-null owner field to non-null owner field is safe without
173 // cmpxchg() as long as all readers can tolerate either flavor.
174 Atomic::store(&_owner, self);
175 log_trace(monitorinflation, owner)("set_owner_from_BasicLock(): mid="
176 INTPTR_FORMAT ", basic_lock_p="
177 INTPTR_FORMAT ", new_value=" INTPTR_FORMAT,
178 p2i(this), p2i(basic_lock_p), p2i(self));
179 }
180
181 // Try to set _owner field to new_value if the current value matches
182 // old_value. Otherwise, does not change the _owner field. Returns
183 // the prior value of the _owner field.
184 inline void* ObjectMonitor::try_set_owner_from(void* old_value, void* new_value) {
185 void* prev = Atomic::cmpxchg(&_owner, old_value, new_value);
186 if (prev == old_value) {
187 log_trace(monitorinflation, owner)("try_set_owner_from(): mid="
188 INTPTR_FORMAT ", prev=" INTPTR_FORMAT
189 ", new=" INTPTR_FORMAT, p2i(this),
190 p2i(prev), p2i(new_value));
191 }
192 return prev;
193 }
194
195 inline void ObjectMonitor::set_allocation_state(ObjectMonitor::AllocationState s) {
196 _allocation_state = s;
197 }
198
199 inline ObjectMonitor::AllocationState ObjectMonitor::allocation_state() const {
200 return _allocation_state;
201 }
202
203 inline bool ObjectMonitor::is_free() const {
204 return _allocation_state == Free;
205 }
206
207 inline bool ObjectMonitor::is_old() const {
208 return _allocation_state == Old;
209 }
210
211 inline bool ObjectMonitor::is_new() const {
212 return _allocation_state == New;
213 }
214
215 inline void ObjectMonitor::dec_ref_count() {
216 Atomic::dec(&_ref_count);
217 // Can be negative as part of async deflation protocol.
218 jint l_ref_count = ref_count();
219 ADIM_guarantee(AsyncDeflateIdleMonitors || l_ref_count >= 0,
220 "sanity check: l_ref_count=%d, ref_count=%d", l_ref_count, ref_count());
221 }
222
223 inline void ObjectMonitor::inc_ref_count() {
224 Atomic::inc(&_ref_count);
225 // Can be negative as part of async deflation protocol.
226 jint l_ref_count = ref_count();
227 ADIM_guarantee(AsyncDeflateIdleMonitors || l_ref_count > 0,
228 "sanity check: l_ref_count=%d, ref_count=%d", l_ref_count, ref_count());
229 }
230
231 inline jint ObjectMonitor::ref_count() const {
232 return Atomic::load(&_ref_count);
233 }
234
235 // The _next_om field can be concurrently read and modified so we
236 // use Atomic operations to disable compiler optimizations that
237 // might try to elide loading and/or storing this field.
238
239 inline ObjectMonitor* ObjectMonitor::next_om() const {
240 return Atomic::load(&_next_om);
241 }
242
243 // Simply set _next_om field to new_value.
244 inline void ObjectMonitor::set_next_om(ObjectMonitor* new_value) {
245 Atomic::store(&_next_om, new_value);
246 }
247
248 // Try to set _next_om field to new_value if the current value matches
249 // old_value. Otherwise, does not change the _next_om field. Returns
250 // the prior value of the _next_om field.
251 inline ObjectMonitor* ObjectMonitor::try_set_next_om(ObjectMonitor* old_value, ObjectMonitor* new_value) {
252 return Atomic::cmpxchg(&_next_om, old_value, new_value);
253 }
254
255 #endif // SHARE_RUNTIME_OBJECTMONITOR_INLINE_HPP