| /* |
| * Copyright (c) 2015, 2020, 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. |
| * |
| */ |
| |
| #ifndef SHARE_GC_G1_G1SERVICETHREAD_HPP |
| #define SHARE_GC_G1_G1SERVICETHREAD_HPP |
| |
| #include "gc/shared/concurrentGCThread.hpp" |
| #include "runtime/mutex.hpp" |
| |
| class G1PeriodicGCTask; |
| class G1RemSetSamplingTask; |
| class G1ServiceTaskQueue; |
| class G1ServiceThread; |
| |
| class G1ServiceTask : public CHeapObj<mtGC> { |
| friend class G1ServiceTaskQueue; |
| friend class G1ServiceThread; |
| |
| // The next absolute time this task should be executed. |
| jlong _time; |
| // Name of the task. |
| const char* _name; |
| // Next task in the task queue. |
| G1ServiceTask* _next; |
| // The service thread this task is registered with. |
| G1ServiceThread* _service_thread; |
| |
| void set_service_thread(G1ServiceThread* thread); |
| bool is_registered(); |
| |
| public: |
| G1ServiceTask(const char* name); |
| |
| jlong time(); |
| const char* name(); |
| G1ServiceTask* next(); |
| |
| // Do the actual work for the task. To get added back to the |
| // execution queue a task can call schedule(delay_ms). |
| virtual void execute() = 0; |
| |
| protected: |
| // Schedule the task on the associated service thread using |
| // the provided delay in milliseconds. Can only be used when |
| // currently running on the service thread. |
| void schedule(jlong delay_ms); |
| |
| // These setters are protected for use by testing and the |
| // sentinel task only. |
| void set_time(jlong time); |
| void set_next(G1ServiceTask* next); |
| }; |
| |
| class G1SentinelTask : public G1ServiceTask { |
| public: |
| G1SentinelTask(); |
| virtual void execute(); |
| }; |
| |
| class G1ServiceTaskQueue { |
| // The sentinel task is the entry point of this priority queue holding the |
| // service tasks. The queue is ordered by the time the tasks are scheduled |
| // to run. To simplify list management the sentinel task has its time set |
| // to max_jlong, guaranteeing it to be the last task in the queue. |
| G1SentinelTask _sentinel; |
| |
| // Verify that the queue is ordered. |
| void verify_task_queue() NOT_DEBUG_RETURN; |
| public: |
| G1ServiceTaskQueue(); |
| G1ServiceTask* pop(); |
| G1ServiceTask* peek(); |
| void add_ordered(G1ServiceTask* task); |
| bool is_empty(); |
| }; |
| |
| // The G1ServiceThread is used to periodically do a number of different tasks: |
| // - re-assess the validity of the prediction for the |
| // remembered set lengths of the young generation. |
| // - check if a periodic GC should be scheduled. |
| class G1ServiceThread: public ConcurrentGCThread { |
| friend class G1ServiceTask; |
| // The monitor is used to ensure thread safety for the task queue |
| // and allow other threads to signal the service thread to wake up. |
| Monitor _monitor; |
| G1ServiceTaskQueue _task_queue; |
| |
| G1RemSetSamplingTask* _remset_task; |
| G1PeriodicGCTask* _periodic_gc_task; |
| |
| double _vtime_accum; // Accumulated virtual time. |
| |
| void run_service(); |
| void stop_service(); |
| |
| // Returns the time in milliseconds until the next task is due. |
| // Used both to determine if there are tasks ready to run and |
| // how long to sleep when nothing is ready. |
| int64_t time_to_next_task_ms(); |
| void sleep_before_next_cycle(); |
| |
| G1ServiceTask* pop_due_task(); |
| void run_task(G1ServiceTask* task); |
| |
| // Helper used by both schedule_task() and G1ServiceTask::schedule() |
| // to schedule a registered task to run after the given delay. |
| void schedule(G1ServiceTask* task, jlong delay); |
| |
| // Notify a change to the service thread. Used to either stop |
| // the service or to force check for new tasks. |
| void notify(); |
| |
| public: |
| G1ServiceThread(); |
| ~G1ServiceThread(); |
| |
| double vtime_accum() { return _vtime_accum; } |
| // Register a task with the service thread and schedule it. If |
| // no delay is specified the task is scheduled to run directly. |
| void register_task(G1ServiceTask* task, jlong delay = 0); |
| |
| // Schedule the task and notify the service thread that a new |
| // task might be ready to run. |
| void schedule_task(G1ServiceTask* task, jlong delay); |
| }; |
| |
| #endif // SHARE_GC_G1_G1SERVICETHREAD_HPP |