| /* |
| * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| #include "memory/allocation.hpp" |
| #include "runtime/init.hpp" |
| #include "runtime/task.hpp" |
| #include "runtime/thread.inline.hpp" |
| #include "runtime/timer.hpp" |
| |
| int PeriodicTask::_num_tasks = 0; |
| PeriodicTask* PeriodicTask::_tasks[PeriodicTask::max_tasks]; |
| #ifndef PRODUCT |
| elapsedTimer PeriodicTask::_timer; |
| int PeriodicTask::_intervalHistogram[PeriodicTask::max_interval]; |
| int PeriodicTask::_ticks; |
| |
| void PeriodicTask::print_intervals() { |
| if (ProfilerCheckIntervals) { |
| for (int i = 0; i < PeriodicTask::max_interval; i++) { |
| int n = _intervalHistogram[i]; |
| if (n > 0) tty->print_cr("%3d: %5d (%4.1f%%)", i, n, 100.0 * n / _ticks); |
| } |
| } |
| } |
| #endif |
| |
| void PeriodicTask::real_time_tick(int delay_time) { |
| assert(Thread::current()->is_Watcher_thread(), "must be WatcherThread"); |
| |
| #ifndef PRODUCT |
| if (ProfilerCheckIntervals) { |
| _ticks++; |
| _timer.stop(); |
| int ms = (int)_timer.milliseconds(); |
| _timer.reset(); |
| _timer.start(); |
| if (ms >= PeriodicTask::max_interval) ms = PeriodicTask::max_interval - 1; |
| _intervalHistogram[ms]++; |
| } |
| #endif |
| |
| { |
| // The WatcherThread does not participate in the safepoint protocol |
| // for the PeriodicTask_lock because it is not a JavaThread. |
| MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); |
| int orig_num_tasks = _num_tasks; |
| |
| for(int index = 0; index < _num_tasks; index++) { |
| _tasks[index]->execute_if_pending(delay_time); |
| if (_num_tasks < orig_num_tasks) { // task dis-enrolled itself |
| index--; // re-do current slot as it has changed |
| orig_num_tasks = _num_tasks; |
| } |
| } |
| } |
| } |
| |
| int PeriodicTask::time_to_wait() { |
| assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); |
| |
| if (_num_tasks == 0) { |
| return 0; // sleep until shutdown or a task is enrolled |
| } |
| |
| int delay = _tasks[0]->time_to_next_interval(); |
| for (int index = 1; index < _num_tasks; index++) { |
| delay = MIN2(delay, _tasks[index]->time_to_next_interval()); |
| } |
| return delay; |
| } |
| |
| |
| PeriodicTask::PeriodicTask(size_t interval_time) : |
| _counter(0), _interval((int) interval_time) { |
| // Sanity check the interval time |
| assert(_interval >= PeriodicTask::min_interval && |
| _interval % PeriodicTask::interval_gran == 0, |
| "improper PeriodicTask interval time"); |
| } |
| |
| PeriodicTask::~PeriodicTask() { |
| // This PeriodicTask may have already been disenrolled by a call |
| // to disenroll() before the PeriodicTask was deleted. |
| disenroll(); |
| } |
| |
| // enroll the current PeriodicTask |
| void PeriodicTask::enroll() { |
| // Follow normal safepoint aware lock enter protocol if the caller does |
| // not already own the PeriodicTask_lock. Otherwise, we don't try to |
| // enter it again because VM internal Mutexes do not support recursion. |
| // |
| MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL |
| : PeriodicTask_lock); |
| |
| if (_num_tasks == PeriodicTask::max_tasks) { |
| fatal("Overflow in PeriodicTask table"); |
| } else { |
| _tasks[_num_tasks++] = this; |
| } |
| |
| WatcherThread* thread = WatcherThread::watcher_thread(); |
| if (thread != NULL) { |
| thread->unpark(); |
| } else { |
| WatcherThread::start(); |
| } |
| } |
| |
| // disenroll the current PeriodicTask |
| void PeriodicTask::disenroll() { |
| // Follow normal safepoint aware lock enter protocol if the caller does |
| // not already own the PeriodicTask_lock. Otherwise, we don't try to |
| // enter it again because VM internal Mutexes do not support recursion. |
| // |
| MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL |
| : PeriodicTask_lock); |
| |
| int index; |
| for(index = 0; index < _num_tasks && _tasks[index] != this; index++) |
| ; |
| |
| if (index == _num_tasks) { |
| return; |
| } |
| |
| _num_tasks--; |
| |
| for (; index < _num_tasks; index++) { |
| _tasks[index] = _tasks[index+1]; |
| } |
| } |