| /* |
| * Copyright (c) 2014, 2016, 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_VM_GC_G1_SUSPENDIBLETHREADSET_HPP |
| #define SHARE_VM_GC_G1_SUSPENDIBLETHREADSET_HPP |
| |
| #include "memory/allocation.hpp" |
| |
| // A SuspendibleThreadSet is a set of threads that can be suspended. |
| // A thread can join and later leave the set, and periodically yield. |
| // If some thread (not in the set) requests, via synchronize(), that |
| // the threads be suspended, then the requesting thread is blocked |
| // until all the threads in the set have yielded or left the set. Threads |
| // may not enter the set when an attempted suspension is in progress. The |
| // suspending thread later calls desynchronize(), allowing the suspended |
| // threads to continue. |
| class SuspendibleThreadSet : public AllStatic { |
| friend class SuspendibleThreadSetJoiner; |
| friend class SuspendibleThreadSetLeaver; |
| |
| private: |
| static uint _nthreads; |
| static uint _nthreads_stopped; |
| static bool _suspend_all; |
| static double _suspend_all_start; |
| |
| static bool is_synchronized(); |
| |
| // Add the current thread to the set. May block if a suspension is in progress. |
| static void join(); |
| |
| // Removes the current thread from the set. |
| static void leave(); |
| |
| public: |
| // Returns true if an suspension is in progress. |
| static bool should_yield() { return _suspend_all; } |
| |
| // Suspends the current thread if a suspension is in progress. |
| static void yield(); |
| |
| // Returns when all threads in the set are suspended. |
| static void synchronize(); |
| |
| // Resumes all suspended threads in the set. |
| static void desynchronize(); |
| }; |
| |
| class SuspendibleThreadSetJoiner : public StackObj { |
| private: |
| bool _active; |
| |
| public: |
| SuspendibleThreadSetJoiner(bool active = true) : _active(active) { |
| if (_active) { |
| SuspendibleThreadSet::join(); |
| } |
| } |
| |
| ~SuspendibleThreadSetJoiner() { |
| if (_active) { |
| SuspendibleThreadSet::leave(); |
| } |
| } |
| |
| bool should_yield() { |
| if (_active) { |
| return SuspendibleThreadSet::should_yield(); |
| } else { |
| return false; |
| } |
| } |
| |
| void yield() { |
| assert(_active, "Thread has not joined the suspendible thread set"); |
| SuspendibleThreadSet::yield(); |
| } |
| }; |
| |
| class SuspendibleThreadSetLeaver : public StackObj { |
| private: |
| bool _active; |
| |
| public: |
| SuspendibleThreadSetLeaver(bool active = true) : _active(active) { |
| if (_active) { |
| SuspendibleThreadSet::leave(); |
| } |
| } |
| |
| ~SuspendibleThreadSetLeaver() { |
| if (_active) { |
| SuspendibleThreadSet::join(); |
| } |
| } |
| }; |
| |
| #endif // SHARE_VM_GC_G1_SUSPENDIBLETHREADSET_HPP |