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 // If needs_fence is true, we issue a fence() after the release_store().
128 // Otherwise, a storeload() is good enough. See the callers for more info.
129 inline void ObjectMonitor::release_clear_owner_with_barrier(void* old_value,
130 bool needs_fence) {
131 void* prev = _owner;
132 ADIM_guarantee(prev == old_value, "unexpected prev owner=" INTPTR_FORMAT
133 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(old_value));
134 Atomic::release_store(&_owner, (void*)NULL);
135 if (needs_fence) {
136 OrderAccess::fence();
137 } else {
138 OrderAccess::storeload();
139 }
140 log_trace(monitorinflation, owner)("release_clear_owner_with_barrier(): mid="
141 INTPTR_FORMAT ", prev=" INTPTR_FORMAT
142 ", needs_fence=%d", p2i(this), p2i(prev),
143 needs_fence);
144 }
145
146 // Simply set _owner field to new_value; current value must match old_value.
147 // (Simple means no memory sync needed.)
148 inline void ObjectMonitor::simply_set_owner_from(void* new_value, void* old_value) {
149 void* prev = _owner;
150 ADIM_guarantee(prev == old_value, "unexpected prev owner=" INTPTR_FORMAT
151 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(old_value));
152 _owner = new_value;
153 log_trace(monitorinflation, owner)("simply_set_owner_from(): mid="
154 INTPTR_FORMAT ", prev=" INTPTR_FORMAT
155 ", new=" INTPTR_FORMAT, p2i(this),
156 p2i(prev), p2i(new_value));
157 }
158
159 // Simply set _owner field to new_value; current value must match old_value1 or old_value2.
160 // (Simple means no memory sync needed.)
161 inline void ObjectMonitor::simply_set_owner_from(void* new_value, void* old_value1, void* old_value2) {
162 void* prev = _owner;
163 ADIM_guarantee(prev == old_value1 || prev == old_value2,
164 "unexpected prev owner=" INTPTR_FORMAT ", expected1="
165 INTPTR_FORMAT " or expected2=" INTPTR_FORMAT, p2i(prev),
166 p2i(old_value1), p2i(old_value2));
167 _owner = new_value;
168 log_trace(monitorinflation, owner)("simply_set_owner_from(old1=" INTPTR_FORMAT
169 ", old2=" INTPTR_FORMAT "): mid="
170 INTPTR_FORMAT ", prev=" INTPTR_FORMAT
171 ", new=" INTPTR_FORMAT, p2i(old_value1),
172 p2i(old_value2), p2i(this), p2i(prev),
173 p2i(new_value));
174 }
175
176 // Simply set _owner field to self; current value must match basic_lock_p.
177 inline void ObjectMonitor::simply_set_owner_from_BasicLock(Thread* self, void* basic_lock_p) {
178 void* prev = _owner;
179 ADIM_guarantee(prev == basic_lock_p, "unexpected prev owner=" INTPTR_FORMAT
180 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(basic_lock_p));
181 // Non-null owner field to non-null owner field is safe without
182 // cmpxchg() as long as all readers can tolerate either flavor.
183 _owner = self;
184 log_trace(monitorinflation, owner)("simply_set_owner_from_BasicLock(): mid="
185 INTPTR_FORMAT ", prev=" INTPTR_FORMAT
186 ", new=" INTPTR_FORMAT ", basic_lock_p="
187 INTPTR_FORMAT, p2i(this), p2i(prev),
188 p2i(self), p2i(basic_lock_p));
189 }
190
191 // Try to set _owner field to new_value if the current value matches
192 // old_value. Otherwise, does not change the _owner field.
193 inline void* ObjectMonitor::try_set_owner_from(void* new_value, void* old_value) {
194 void* prev = Atomic::cmpxchg(&_owner, old_value, new_value);
195 if (prev == old_value) {
196 log_trace(monitorinflation, owner)("try_set_owner_from(): mid="
197 INTPTR_FORMAT ", prev=" INTPTR_FORMAT
198 ", new=" INTPTR_FORMAT, p2i(this),
199 p2i(prev), p2i(new_value));
200 }
201 return prev;
202 }
203
204 inline void ObjectMonitor::set_allocation_state(ObjectMonitor::AllocationState s) {
205 _allocation_state = s;
206 }
207
208 inline ObjectMonitor::AllocationState ObjectMonitor::allocation_state() const {
209 return _allocation_state;
210 }
211
212 inline bool ObjectMonitor::is_free() const {
213 return _allocation_state == Free;
214 }
215
216 inline bool ObjectMonitor::is_old() const {
217 return _allocation_state == Old;
218 }
219
220 inline bool ObjectMonitor::is_new() const {
221 return _allocation_state == New;
222 }
223
224 inline void ObjectMonitor::dec_ref_count() {
225 Atomic::dec(&_ref_count);
226 // Can be negative as part of async deflation protocol.
227 jint l_ref_count = ref_count();
228 ADIM_guarantee(AsyncDeflateIdleMonitors || l_ref_count >= 0,
229 "sanity check: l_ref_count=%d, ref_count=%d", l_ref_count, ref_count());
230 }
231
232 inline void ObjectMonitor::inc_ref_count() {
233 Atomic::inc(&_ref_count);
234 // Can be negative as part of async deflation protocol.
235 jint l_ref_count = ref_count();
236 ADIM_guarantee(AsyncDeflateIdleMonitors || l_ref_count > 0,
237 "sanity check: l_ref_count=%d, ref_count=%d", l_ref_count, ref_count());
238 }
239
240 inline jint ObjectMonitor::ref_count() const {
241 return Atomic::load(&_ref_count);
242 }
243
244 #endif // SHARE_RUNTIME_OBJECTMONITOR_INLINE_HPP