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(hdr, &_header);
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 DEBUG_ONLY(jint l_ref_count = ref_count();)
72 assert(l_ref_count == 0, "must be 0: l_ref_count=%d, ref_count=%d", l_ref_count, ref_count());
73
74 Atomic::store(markWord::zero(), &_header);
75
76 clear_using_JT();
77 }
78
79 inline void ObjectMonitor::clear_using_JT() {
80 // Unlike other *_using_JT() functions, we cannot assert
81 // AsyncDeflateIdleMonitors or Thread::current()->is_Java_thread()
82 // because clear() calls this function for the rest of its checks.
83
84 if (AsyncDeflateIdleMonitors) {
85 // Async deflation protocol uses the header, owner and ref_count
86 // fields. While the ObjectMonitor being deflated is on the global free
87 // list, we leave those three fields alone; owner == DEFLATER_MARKER
88 // and ref_count < 0 will force any racing threads to retry. The
89 // header field is used by install_displaced_markword_in_object()
90 // in the last part of the deflation protocol so we cannot check
91 // its value here.
92 guarantee(_owner == NULL || _owner == DEFLATER_MARKER,
93 "must be NULL or DEFLATER_MARKER: owner=" INTPTR_FORMAT,
94 p2i(_owner));
95 jint l_ref_count = ref_count();
96 guarantee(l_ref_count <= 0, "must be <= 0: l_ref_count=%d, ref_count=%d", l_ref_count, ref_count());
97 }
98 assert(_contentions == 0, "must be 0: contentions=%d", _contentions);
99 assert(_waiters == 0, "must be 0: waiters=%d", _waiters);
100 assert(_recursions == 0, "must be 0: recursions=" INTX_FORMAT, _recursions);
101 assert(_object != NULL, "must be non-NULL");
102
103 set_allocation_state(Free);
104 _object = NULL;
105 }
106
107 inline void* ObjectMonitor::object() const {
108 return _object;
109 }
110
111 inline void* ObjectMonitor::object_addr() {
112 return (void *)(&_object);
113 }
114
115 inline void ObjectMonitor::set_object(void* obj) {
116 _object = obj;
117 }
118
119 // return number of threads contending for this monitor
120 inline jint ObjectMonitor::contentions() const {
121 return _contentions;
122 }
123
124 // Set _owner field to new_value; current value must match old_value.
125 inline void ObjectMonitor::set_owner_from(void* new_value, void* old_value) {
126 void* prev = Atomic::cmpxchg(new_value, &_owner, old_value);
127 ADIM_guarantee(prev == old_value, "unexpected prev owner=" INTPTR_FORMAT
128 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(old_value));
129 log_trace(monitorinflation, owner)("set_owner_from(): mid=" INTPTR_FORMAT
130 ", prev=" INTPTR_FORMAT ", new="
131 INTPTR_FORMAT, p2i(this), p2i(prev),
132 p2i(new_value));
133 }
134
135 // Simply set _owner field to new_value; current value must match old_value.
136 // (Simple means no memory sync needed.)
137 inline void ObjectMonitor::simply_set_owner_from(void* new_value, void* old_value) {
138 void* prev = _owner;
139 ADIM_guarantee(prev == old_value, "unexpected prev owner=" INTPTR_FORMAT
140 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(old_value));
141 _owner = new_value;
142 log_trace(monitorinflation, owner)("simply_set_owner_from(): mid="
143 INTPTR_FORMAT ", prev=" INTPTR_FORMAT
144 ", new=" INTPTR_FORMAT, p2i(this),
145 p2i(prev), p2i(new_value));
146 }
147
148 // Simply set _owner field to new_value; current value must match old_value1 or old_value2.
149 // (Simple means no memory sync needed.)
150 inline void ObjectMonitor::simply_set_owner_from(void* new_value, void* old_value1, void* old_value2) {
151 void* prev = _owner;
152 ADIM_guarantee(prev == old_value1 || prev == old_value2,
153 "unexpected prev owner=" INTPTR_FORMAT ", expected1="
154 INTPTR_FORMAT " or expected2=" INTPTR_FORMAT, p2i(prev),
155 p2i(old_value1), p2i(old_value2));
156 _owner = new_value;
157 log_trace(monitorinflation, owner)("simply_set_owner_from(old1=" INTPTR_FORMAT
158 ", old2=" INTPTR_FORMAT "): mid="
159 INTPTR_FORMAT ", prev=" INTPTR_FORMAT
160 ", new=" INTPTR_FORMAT, p2i(old_value1),
161 p2i(old_value2), p2i(this), p2i(prev),
162 p2i(new_value));
163 }
164
165 // Simply set _owner field to self; current value must match basic_lock_p.
166 inline void ObjectMonitor::simply_set_owner_from_BasicLock(Thread* self, void* basic_lock_p) {
167 void* prev = _owner;
168 ADIM_guarantee(prev == basic_lock_p, "unexpected prev owner=" INTPTR_FORMAT
169 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(basic_lock_p));
170 // Non-null owner field to non-null owner field is safe without
171 // cmpxchg() as long as all readers can tolerate either flavor.
172 _owner = self;
173 log_trace(monitorinflation, owner)("simply_set_owner_from_BasicLock(): mid="
174 INTPTR_FORMAT ", prev=" INTPTR_FORMAT
175 ", new=" INTPTR_FORMAT ", basic_lock_p="
176 INTPTR_FORMAT, p2i(this), p2i(prev),
177 p2i(self), p2i(basic_lock_p));
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.
182 inline void* ObjectMonitor::try_set_owner_from(void* new_value, void* old_value) {
183 void* prev = Atomic::cmpxchg(new_value, &_owner, old_value);
184 if (prev == old_value) {
185 log_trace(monitorinflation, owner)("try_set_owner_from(): mid="
186 INTPTR_FORMAT ", prev=" INTPTR_FORMAT
187 ", new=" INTPTR_FORMAT, p2i(this),
188 p2i(prev), p2i(new_value));
189 }
190 return prev;
191 }
192
193 inline void ObjectMonitor::set_allocation_state(ObjectMonitor::AllocationState s) {
194 _allocation_state = s;
195 }
196
197 inline ObjectMonitor::AllocationState ObjectMonitor::allocation_state() const {
198 return _allocation_state;
199 }
200
201 inline bool ObjectMonitor::is_free() const {
202 return _allocation_state == Free;
203 }
204
205 inline bool ObjectMonitor::is_old() const {
206 return _allocation_state == Old;
207 }
208
209 inline bool ObjectMonitor::is_new() const {
210 return _allocation_state == New;
211 }
212
213 inline void ObjectMonitor::dec_ref_count() {
214 // The decrement only needs to be MO_ACQ_REL since the reference
215 // counter is volatile.
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 // The increment needs to be MO_SEQ_CST so that the reference
225 // counter update is seen as soon as possible in a race with the
226 // async deflation protocol.
227 Atomic::inc(&_ref_count);
228 // Can be negative as part of async deflation protocol.
229 jint l_ref_count = ref_count();
230 ADIM_guarantee(AsyncDeflateIdleMonitors || l_ref_count > 0,
231 "sanity check: l_ref_count=%d, ref_count=%d", l_ref_count, ref_count());
232 }
233
234 inline jint ObjectMonitor::ref_count() const {
235 return _ref_count;
236 }
237
238 #endif // SHARE_RUNTIME_OBJECTMONITOR_INLINE_HPP