Tue, 15 Mar 2011 06:35:10 -0700
7024234: 2/3 jvmti tests fail assert(!_oops_are_stale) failed: oops are stale on Win-AMD64
Summary: Move initialization of the '_instance' field to avoid race with ServiceThread start.
Reviewed-by: dholmes, kamg, never, dsamersoff, ysr, coleenp, acorn
duke@435 | 1 | /* |
stefank@2314 | 2 | * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
trims@1907 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
trims@1907 | 20 | * or visit www.oracle.com if you need additional information or have any |
trims@1907 | 21 | * questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
stefank@2314 | 25 | #ifndef SHARE_VM_RUNTIME_TASK_HPP |
stefank@2314 | 26 | #define SHARE_VM_RUNTIME_TASK_HPP |
stefank@2314 | 27 | |
stefank@2314 | 28 | #include "utilities/top.hpp" |
stefank@2314 | 29 | |
duke@435 | 30 | // A PeriodicTask has the sole purpose of executing its task |
duke@435 | 31 | // function with regular intervals. |
duke@435 | 32 | // Usage: |
duke@435 | 33 | // PeriodicTask pf(10); |
duke@435 | 34 | // pf.enroll(); |
duke@435 | 35 | // ... |
duke@435 | 36 | // pf.disenroll(); |
duke@435 | 37 | |
duke@435 | 38 | class PeriodicTask: public CHeapObj { |
duke@435 | 39 | public: |
duke@435 | 40 | // Useful constants. |
duke@435 | 41 | // The interval constants are used to ensure the declared interval |
duke@435 | 42 | // is appropriate; it must be between min_interval and max_interval, |
duke@435 | 43 | // and have a granularity of interval_gran (all in millis). |
duke@435 | 44 | enum { max_tasks = 10, // Max number of periodic tasks in system |
duke@435 | 45 | interval_gran = 10, |
duke@435 | 46 | min_interval = 10, |
duke@435 | 47 | max_interval = 10000 }; |
duke@435 | 48 | |
duke@435 | 49 | static int num_tasks() { return _num_tasks; } |
duke@435 | 50 | |
duke@435 | 51 | private: |
duke@435 | 52 | size_t _counter; |
duke@435 | 53 | const size_t _interval; |
duke@435 | 54 | |
duke@435 | 55 | static int _num_tasks; |
duke@435 | 56 | static PeriodicTask* _tasks[PeriodicTask::max_tasks]; |
duke@435 | 57 | static void real_time_tick(size_t delay_time); |
duke@435 | 58 | |
duke@435 | 59 | #ifndef PRODUCT |
duke@435 | 60 | static elapsedTimer _timer; // measures time between ticks |
duke@435 | 61 | static int _ticks; // total number of ticks |
duke@435 | 62 | static int _intervalHistogram[max_interval]; // to check spacing of timer interrupts |
duke@435 | 63 | public: |
duke@435 | 64 | static void print_intervals(); |
duke@435 | 65 | #endif |
duke@435 | 66 | // Only the WatcherThread can cause us to execute PeriodicTasks |
duke@435 | 67 | friend class WatcherThread; |
duke@435 | 68 | public: |
duke@435 | 69 | PeriodicTask(size_t interval_time); // interval is in milliseconds of elapsed time |
duke@435 | 70 | ~PeriodicTask(); |
duke@435 | 71 | |
duke@435 | 72 | // Tells whether is enrolled |
duke@435 | 73 | bool is_enrolled() const; |
duke@435 | 74 | |
duke@435 | 75 | // Make the task active |
duke@435 | 76 | // NOTE: this may only be called before the WatcherThread has been started |
duke@435 | 77 | void enroll(); |
duke@435 | 78 | |
duke@435 | 79 | // Make the task deactive |
duke@435 | 80 | // NOTE: this may only be called either while the WatcherThread is |
duke@435 | 81 | // inactive or by a task from within its task() method. One-shot or |
duke@435 | 82 | // several-shot tasks may be implemented this way. |
duke@435 | 83 | void disenroll(); |
duke@435 | 84 | |
duke@435 | 85 | void execute_if_pending(size_t delay_time) { |
duke@435 | 86 | _counter += delay_time; |
duke@435 | 87 | if (_counter >= _interval) { |
duke@435 | 88 | _counter = 0; |
duke@435 | 89 | task(); |
duke@435 | 90 | } |
duke@435 | 91 | } |
duke@435 | 92 | |
duke@435 | 93 | // Returns how long (time in milliseconds) before the next time we should |
duke@435 | 94 | // execute this task. |
duke@435 | 95 | size_t time_to_next_interval() const { |
duke@435 | 96 | assert(_interval > _counter, "task counter greater than interval?"); |
duke@435 | 97 | return _interval - _counter; |
duke@435 | 98 | } |
duke@435 | 99 | |
duke@435 | 100 | // Calculate when the next periodic task will fire. |
duke@435 | 101 | // Called by the WatcherThread's run method. |
duke@435 | 102 | // This assumes that periodic tasks aren't entering the system |
duke@435 | 103 | // dynamically, except for during startup. |
duke@435 | 104 | static size_t time_to_wait() { |
duke@435 | 105 | if (_num_tasks == 0) { |
duke@435 | 106 | // Don't wait any more; shut down the thread since we don't |
duke@435 | 107 | // currently support dynamic enrollment. |
duke@435 | 108 | return 0; |
duke@435 | 109 | } |
duke@435 | 110 | |
duke@435 | 111 | size_t delay = _tasks[0]->time_to_next_interval(); |
duke@435 | 112 | for (int index = 1; index < _num_tasks; index++) { |
duke@435 | 113 | delay = MIN2(delay, _tasks[index]->time_to_next_interval()); |
duke@435 | 114 | } |
duke@435 | 115 | return delay; |
duke@435 | 116 | } |
duke@435 | 117 | |
duke@435 | 118 | // The task to perform at each period |
duke@435 | 119 | virtual void task() = 0; |
duke@435 | 120 | }; |
stefank@2314 | 121 | |
stefank@2314 | 122 | #endif // SHARE_VM_RUNTIME_TASK_HPP |