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 inline intptr_t ObjectMonitor::is_entered(TRAPS) const {
29 if (THREAD == _owner || THREAD->is_lock_owned((address) _owner)) {
30 return 1;
31 }
32 return 0;
33 }
34
35 inline markOop ObjectMonitor::header() const {
36 return _header;
37 }
38
39 inline volatile markOop* ObjectMonitor::header_addr() {
40 assert((intptr_t)this == (intptr_t)&_header, "sync code expects this");
41 return &_header;
42 }
43
44 inline void ObjectMonitor::set_header(markOop hdr) {
45 _header = hdr;
46 }
47
48 inline jint ObjectMonitor::count() const {
49 return _count;
50 }
51
52 inline jint ObjectMonitor::waiters() const {
53 return _waiters;
54 }
55
56 // Returns NULL if DEFLATER_MARKER is observed.
57 inline void* ObjectMonitor::owner() const {
58 void* owner = _owner;
59 return owner != DEFLATER_MARKER ? owner : NULL;
60 }
61
62 inline void ObjectMonitor::clear() {
63 assert(_count == 0, "Fatal logic error in ObjectMonitor count!");
64 assert(_owner == NULL, "Fatal logic error in ObjectMonitor owner!");
65
66 clear_using_JT();
67 }
68
69 inline void ObjectMonitor::clear_using_JT() {
70 // When clearing using a JavaThread, we leave _owner == DEFLATER_MARKER
71 // and _count < 0 to force any racing threads to retry. Unlike other
72 // *_using_JT() functions, we cannot assert AsyncDeflateIdleMonitors
73 // or Thread::current()->is_Java_thread() because clear() calls this
74 // function for the rest of its checks.
75
76 assert(_header != NULL, "Fatal logic error in ObjectMonitor header!");
77 assert(_waiters == 0, "Fatal logic error in ObjectMonitor waiters!");
78 assert(_recursions == 0, "Fatal logic error in ObjectMonitor recursions!");
79 assert(_object != NULL, "Fatal logic error in ObjectMonitor object!");
80 // Do not assert _ref_count == 0 here because a racing thread could
81 // increment _ref_count, observe _owner == DEFLATER_MARKER and then
82 // decrement _ref_count.
83
84 set_allocation_state(Free);
85 _header = NULL;
86 _object = NULL;
87 // Do not clear _ref_count here because _ref_count is for indicating
88 // that the ObjectMonitor* is in use which is orthogonal to whether
89 // the ObjectMonitor itself is in use for a locking operation.
90 }
91
92 inline void* ObjectMonitor::object() const {
93 return _object;
94 }
95
96 inline void* ObjectMonitor::object_addr() {
97 return (void *)(&_object);
98 }
99
100 inline void ObjectMonitor::set_object(void* obj) {
101 _object = obj;
102 }
103
104 inline bool ObjectMonitor::check(TRAPS) {
105 if (THREAD != _owner) {
106 if (THREAD->is_lock_owned((address) _owner)) {
107 _owner = THREAD; // regain ownership of inflated monitor
108 assert (_recursions == 0, "invariant") ;
109 } else {
110 check_slow(THREAD);
111 return false;
112 }
113 }
114 return true;
115 }
116
117 // return number of threads contending for this monitor
118 inline jint ObjectMonitor::contentions() const {
119 return _count;
120 }
121
122 // Do NOT set _count = 0. There is a race such that _count could
123 // be set while inflating prior to setting _owner
124 // Just use Atomic::inc/dec and assert 0 when monitor put on free list
125 inline void ObjectMonitor::set_owner(void* owner) {
126 _owner = owner;
127 _recursions = 0;
128 }
129
130 inline void ObjectMonitor::set_allocation_state(ObjectMonitor::AllocationState s) {
131 _allocation_state = s;
132 }
133
134 inline ObjectMonitor::AllocationState ObjectMonitor::allocation_state() const {
135 return _allocation_state;
136 }
137
138 inline bool ObjectMonitor::is_free() const {
139 return _allocation_state == Free;
140 }
141
142 inline bool ObjectMonitor::is_active() const {
143 return !is_free();
144 }
145
146 inline bool ObjectMonitor::is_old() const {
147 return _allocation_state == Old;
148 }
149
150 inline bool ObjectMonitor::is_new() const {
151 return _allocation_state == New;
152 }
153
154 inline void ObjectMonitor::dec_ref_count() {
155 // The decrement needs to be MO_ACQ_REL. At the moment, the Atomic::dec
156 // backend on PPC does not yet conform to these requirements. Therefore
157 // the decrement is simulated with an Atomic::sub(1, &addr). Without
158 // this MO_ACQ_REL Atomic::dec simulation, AsyncDeflateIdleMonitors is
159 // not safe.
160 Atomic::sub((jint)1, &_ref_count);
161 guarantee(_ref_count >= 0, "sanity check: ref_count=%d", _ref_count);
162 }
163
164 inline void ObjectMonitor::inc_ref_count() {
165 // The increment needs to be MO_SEQ_CST. At the moment, the Atomic::inc
166 // backend on PPC does not yet conform to these requirements. Therefore
167 // the increment is simulated with a load phi; cas phi + 1; loop.
168 // Without this MO_SEQ_CST Atomic::inc simulation, AsyncDeflateIdleMonitors
169 // is not safe.
170 for (;;) {
171 jint sample = OrderAccess::load_acquire(&_ref_count);
172 guarantee(sample >= 0, "sanity check: sample=%d", (int)sample);
173 if (Atomic::cmpxchg(sample + 1, &_ref_count, sample) == sample) {
174 // Incremented _ref_count without interference.
175 return;
176 }
177 // Implied else: Saw interference so loop and try again.
178 }
179 }
180
181 inline jint ObjectMonitor::ref_count() const {
182 return OrderAccess::load_acquire(&_ref_count);
183 }
184
185 #endif // SHARE_RUNTIME_OBJECTMONITOR_INLINE_HPP