1 /* 2 * Copyright (c) 2017, Google 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_VM_PRIMS_JVMTIHEAPSAMPLING_HPP 26 #define SHARE_VM_PRIMS_JVMTIHEAPSAMPLING_HPP 27 28 // TODO(jcbeyler): is there a better/standard JVM way of doing this? 29 // A RAII class that handles transitions from the agent into the VM. 30 class HeapThreadTransition : StackObj { 31 private: 32 JavaThreadState _saved_state; 33 JavaThread *_jthread; 34 35 public: 36 // Transitions this thread from the agent (thread_in_native) to the VM. 37 HeapThreadTransition(Thread *thread) { 38 if (thread->is_Java_thread()) { 39 _jthread = static_cast<JavaThread *>(thread); 40 _saved_state = _jthread->thread_state(); 41 if (_saved_state == _thread_in_native) { 42 ThreadStateTransition::transition_from_native(_jthread, _thread_in_vm); 43 } else { 44 ThreadStateTransition::transition(_jthread, 45 _saved_state, 46 _thread_in_vm); 47 } 48 } else { 49 _jthread = NULL; 50 _saved_state = _thread_new; 51 } 52 } 53 54 // Transitions this thread back to the agent from the VM. 55 ~HeapThreadTransition() { 56 if (_jthread != NULL) { 57 ThreadStateTransition::transition(_jthread, _thread_in_vm, _saved_state); 58 } 59 } 60 }; 61 62 #endif // SHARE_VM_PRIMS_JVMTIHEAPSAMPLING_HPP