1 /* 2 * Copyright (c) 1998, 2024, 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 "runtime/objectMonitor.hpp" 29 30 #include "logging/log.hpp" 31 #include "oops/access.inline.hpp" 32 #include "runtime/atomic.hpp" 33 #include "runtime/javaThread.inline.hpp" 34 #include "runtime/lockStack.inline.hpp" 35 #include "runtime/synchronizer.hpp" 36 #include "runtime/threadIdentifier.hpp" 37 38 inline void* ObjectMonitor::owner_for(JavaThread* thread) const { 39 int64_t tid = thread->lock_id(); 40 assert(tid >= 3 && tid < ThreadIdentifier::current(), "must be reasonable"); 41 return (void*)tid; 42 } 43 44 inline bool ObjectMonitor::is_entered(JavaThread* current) const { 45 if (is_owner_anonymous()) { 46 if (LockingMode == LM_LIGHTWEIGHT) { 47 return current->lock_stack().contains(object()); 48 } else { 49 return current->is_lock_owned((address)stack_locker()); 50 } 51 } else { 52 return is_owner(current); 53 } 54 return false; 55 } 56 57 inline markWord ObjectMonitor::header() const { 58 return Atomic::load(&_header); 59 } 60 61 inline volatile markWord* ObjectMonitor::header_addr() { 62 return &_header; 63 } 64 65 inline void ObjectMonitor::set_header(markWord hdr) { 66 Atomic::store(&_header, hdr); 67 } 68 69 inline int ObjectMonitor::waiters() const { 70 return _waiters; 71 } 72 73 inline bool ObjectMonitor::has_owner() const { 74 void* owner = owner_raw(); 75 return owner != nullptr && owner != DEFLATER_MARKER; 76 } 77 78 // Returns null if DEFLATER_MARKER is observed. 79 inline void* ObjectMonitor::owner() const { 80 void* owner = owner_raw(); 81 return owner != DEFLATER_MARKER ? owner : nullptr; 82 } 83 84 inline void* ObjectMonitor::owner_raw() const { 85 return Atomic::load(&_owner); 86 } 87 88 inline BasicLock* ObjectMonitor::stack_locker() const { 89 return Atomic::load(&_stack_locker); 90 } 91 92 inline void ObjectMonitor::set_stack_locker(BasicLock* locker) { 93 Atomic::store(&_stack_locker, locker); 94 } 95 96 inline bool ObjectMonitor::is_stack_locker(JavaThread* current) { 97 return is_owner_anonymous() && current->is_lock_owned((address)stack_locker()); 98 } 99 100 // Returns true if owner field == DEFLATER_MARKER and false otherwise. 101 // This accessor is called when we really need to know if the owner 102 // field == DEFLATER_MARKER and any non-null value won't do the trick. 103 inline bool ObjectMonitor::owner_is_DEFLATER_MARKER() const { 104 return owner_raw() == DEFLATER_MARKER; 105 } 106 107 // Returns true if 'this' is being async deflated and false otherwise. 108 inline bool ObjectMonitor::is_being_async_deflated() { 109 return contentions() < 0; 110 } 111 112 // Return number of threads contending for this monitor. 113 inline int ObjectMonitor::contentions() const { 114 return Atomic::load(&_contentions); 115 } 116 117 // Add value to the contentions field. 118 inline void ObjectMonitor::add_to_contentions(int value) { 119 Atomic::add(&_contentions, value); 120 } 121 122 inline void ObjectMonitor::set_recursions(size_t recursions) { 123 assert(_recursions == 0, "must be"); 124 assert(has_owner(), "must be owned"); 125 _recursions = checked_cast<intx>(recursions); 126 } 127 128 // Clear _owner field; current value must match old_value. 129 inline void ObjectMonitor::release_clear_owner(JavaThread* old_owner) { 130 void* old_value = owner_for(old_owner); 131 #ifdef ASSERT 132 void* prev = Atomic::load(&_owner); 133 assert(prev == old_value, "unexpected prev owner=" INTPTR_FORMAT 134 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(old_value)); 135 #endif 136 Atomic::release_store(&_owner, (void*)nullptr); 137 log_trace(monitorinflation, owner)("release_clear_owner(): mid=" 138 INTPTR_FORMAT ", old_value=" INTPTR_FORMAT, 139 p2i(this), p2i(old_value)); 140 } 141 142 // Simply set _owner field to new_value; current value must match old_value. 143 // (Simple means no memory sync needed.) 144 inline void ObjectMonitor::set_owner_from_raw(void* old_value, void* new_value) { 145 #ifdef ASSERT 146 void* prev = Atomic::load(&_owner); 147 assert((int64_t)prev < ThreadIdentifier::current(), "must be reasonable"); 148 assert(prev == old_value, "unexpected prev owner=" INTPTR_FORMAT 149 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(old_value)); 150 #endif 151 Atomic::store(&_owner, new_value); 152 log_trace(monitorinflation, owner)("set_owner_from(): mid=" 153 INTPTR_FORMAT ", old_value=" INTPTR_FORMAT 154 ", new_value=" INTPTR_FORMAT, p2i(this), 155 p2i(old_value), p2i(new_value)); 156 } 157 158 inline void ObjectMonitor::set_owner_from(void* old_value, JavaThread* current) { 159 set_owner_from_raw(old_value, owner_for(current)); 160 } 161 162 // Simply set _owner field to self; current value must match basic_lock_p. 163 inline void ObjectMonitor::set_owner_from_BasicLock(JavaThread* current) { 164 BasicLock* basic_lock_p = stack_locker(); 165 166 set_stack_locker(nullptr); // first 167 assert(is_owner_anonymous(), "should be anon for now"); 168 169 // Non-null owner field to non-null owner field is safe without 170 // cmpxchg() as long as all readers can tolerate either flavor. 171 Atomic::store(&_owner, owner_for(current)); 172 log_trace(monitorinflation, owner)("set_owner_from_BasicLock(): mid=" 173 INTPTR_FORMAT ", basic_lock_p=" 174 INTPTR_FORMAT ", new_value=" INTPTR_FORMAT, 175 p2i(this), p2i(basic_lock_p), p2i(current)); 176 } 177 178 // Try to set _owner field to new_value if the current value matches 179 // old_value. Otherwise, does not change the _owner field. Returns 180 // the prior value of the _owner field. 181 inline void* ObjectMonitor::try_set_owner_from_raw(void* old_value, void* new_value) { 182 assert((int64_t)new_value < ThreadIdentifier::current(), "must be reasonable"); 183 void* prev = Atomic::cmpxchg(&_owner, old_value, new_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::try_set_owner_from(void* old_value, JavaThread* current) { 194 return try_set_owner_from_raw(old_value, owner_for(current)); 195 } 196 197 // The _next_om field can be concurrently read and modified so we 198 // use Atomic operations to disable compiler optimizations that 199 // might try to elide loading and/or storing this field. 200 201 // Simply get _next_om field. 202 inline ObjectMonitor* ObjectMonitor::next_om() const { 203 return Atomic::load(&_next_om); 204 } 205 206 // Simply set _next_om field to new_value. 207 inline void ObjectMonitor::set_next_om(ObjectMonitor* new_value) { 208 Atomic::store(&_next_om, new_value); 209 } 210 211 #endif // SHARE_RUNTIME_OBJECTMONITOR_INLINE_HPP