1 /* 2 * Copyright (c) 1998, 2012, 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_VM_RUNTIME_VMTHREAD_HPP 26 #define SHARE_VM_RUNTIME_VMTHREAD_HPP 27 28 #include "runtime/perfData.hpp" 29 #include "runtime/vm_operations.hpp" 30 #ifdef TARGET_OS_FAMILY_linux 31 # include "thread_linux.inline.hpp" 32 #endif 33 #ifdef TARGET_OS_FAMILY_solaris 34 # include "thread_solaris.inline.hpp" 35 #endif 36 #ifdef TARGET_OS_FAMILY_windows 37 # include "thread_windows.inline.hpp" 38 #endif 39 #ifdef TARGET_OS_FAMILY_bsd 40 # include "thread_bsd.inline.hpp" 41 #endif 42 43 // 44 // Prioritized queue of VM operations. 45 // 46 // Encapsulates both queue management and 47 // and priority policy 48 // 49 class VMOperationQueue : public CHeapObj<mtInternal> { 50 private: 51 enum Priorities { 52 SafepointPriority, // Highest priority (operation executed at a safepoint) 53 MediumPriority, // Medium priority 54 nof_priorities 55 }; 56 57 // We maintain a doubled linked list, with explicit count. 58 int _queue_length[nof_priorities]; 59 int _queue_counter; 60 VM_Operation* _queue [nof_priorities]; 61 // we also allow the vmThread to register the ops it has drained so we 62 // can scan them from oops_do 63 VM_Operation* _drain_list; 64 65 // Double-linked non-empty list insert. 66 void insert(VM_Operation* q,VM_Operation* n); 67 void unlink(VM_Operation* q); 68 69 // Basic queue manipulation 70 bool queue_empty (int prio); 71 void queue_add_front (int prio, VM_Operation *op); 72 void queue_add_back (int prio, VM_Operation *op); 73 VM_Operation* queue_remove_front(int prio); 74 void queue_oops_do(int queue, OopClosure* f); 75 void drain_list_oops_do(OopClosure* f); 76 VM_Operation* queue_drain(int prio); 77 // lock-free query: may return the wrong answer but must not break 78 bool queue_peek(int prio) { return _queue_length[prio] > 0; } 79 80 public: 81 VMOperationQueue(); 82 83 // Highlevel operations. Encapsulates policy 84 bool add(VM_Operation *op); 85 VM_Operation* remove_next(); // Returns next or null 86 VM_Operation* remove_next_at_safepoint_priority() { return queue_remove_front(SafepointPriority); } 87 VM_Operation* drain_at_safepoint_priority() { return queue_drain(SafepointPriority); } 88 void set_drain_list(VM_Operation* list) { _drain_list = list; } 89 bool peek_at_safepoint_priority() { return queue_peek(SafepointPriority); } 90 91 // GC support 92 void oops_do(OopClosure* f); 93 94 void verify_queue(int prio) PRODUCT_RETURN; 95 }; 96 97 98 // 99 // A single VMThread (the primordial thread) spawns all other threads 100 // and is itself used by other threads to offload heavy vm operations 101 // like scavenge, garbage_collect etc. 102 // 103 104 class VMThread: public NamedThread { 105 private: 106 static ThreadPriority _current_priority; 107 108 static bool _should_terminate; 109 static bool _terminated; 110 static Monitor * _terminate_lock; 111 static PerfCounter* _perf_accumulated_vm_operation_time; 112 113 void evaluate_operation(VM_Operation* op); 114 public: 115 // Constructor 116 VMThread(); 117 118 // Tester 119 bool is_VM_thread() const { return true; } 120 bool is_GC_thread() const { return true; } 121 122 // The ever running loop for the VMThread 123 void loop(); 124 125 // Called to stop the VM thread 126 static void wait_for_vm_thread_exit(); 127 static bool should_terminate() { return _should_terminate; } 128 static bool is_terminated() { return _terminated == true; } 129 130 // Execution of vm operation 131 static void execute(VM_Operation* op); 132 133 // Returns the current vm operation if any. 134 static VM_Operation* vm_operation() { return _cur_vm_operation; } 135 136 // Returns the single instance of VMThread. 137 static VMThread* vm_thread() { return _vm_thread; } 138 139 // GC support 140 void oops_do(OopClosure* f, CodeBlobClosure* cf); 141 142 // Debugging 143 void print_on(outputStream* st) const; 144 void print() const { print_on(tty); } 145 void verify(); 146 147 // Performance measurement 148 static PerfCounter* perf_accumulated_vm_operation_time() { return _perf_accumulated_vm_operation_time; } 149 150 // Entry for starting vm thread 151 virtual void run(); 152 153 // Creations/Destructions 154 static void create(); 155 static void destroy(); 156 157 private: 158 // VM_Operation support 159 static VM_Operation* _cur_vm_operation; // Current VM operation 160 static VMOperationQueue* _vm_queue; // Queue (w/ policy) of VM operations 161 162 // Pointer to single-instance of VM thread 163 static VMThread* _vm_thread; 164 }; 165 166 #endif // SHARE_VM_RUNTIME_VMTHREAD_HPP