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 assert(prev == old_value, "unexpected prev owner=" INTPTR_FORMAT 128 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(old_value)); 129 #endif 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 assert(prev == old_value, "unexpected prev owner=" INTPTR_FORMAT 142 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(old_value)); 143 #endif 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 assert(prev == basic_lock_p, "unexpected prev owner=" INTPTR_FORMAT 173 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(basic_lock_p)); 174 #endif 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