vmThread.hpp revision 3465:d2a62e0f25eb 
1/*
2 * Copyright (c) 1998, 2010, 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
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7 * published by the Free Software Foundation.
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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.
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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//
49class 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
104class 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
167