1 /* 2 * Copyright (c) 2018, 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 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 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. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_UTILITIES_WAITBARRIER_GENERIC_HPP 26 #define SHARE_UTILITIES_WAITBARRIER_GENERIC_HPP 27 28 #include "memory/allocation.hpp" 29 #include "runtime/semaphore.hpp" 30 31 // Except for the barrier tag itself, it uses two counters to keep the semaphore 32 // count correct and not leave any late thread waiting. 33 class GenericWaitBarrier : public CHeapObj<mtInternal> { 34 volatile int _barrier_tag; 35 // The number of threads waiting on or about to wait on the semaphore. 36 volatile int _waiters; 37 // The number of threads in the wait path, before or after the tag check. 38 // These threads can become waiters. 39 volatile int _barrier_threads; 40 Semaphore _sem_barrier; 41 42 // Prevent copying and assignment of GenericWaitBarrier instances. 43 GenericWaitBarrier(const GenericWaitBarrier&); 44 GenericWaitBarrier& operator=(const GenericWaitBarrier&); 45 46 int wake_if_needed(); 47 48 public: 49 GenericWaitBarrier() : _barrier_tag(0), _waiters(0), _barrier_threads(0), _sem_barrier(0) {} 50 ~GenericWaitBarrier() {} 51 52 const char* description() { return "semaphore"; } 53 54 void arm(int barrier_tag); 55 void disarm(); 56 void wake(); 57 void wait(int barrier_tag); 58 }; 59 60 #endif // SHARE_UTILITIES_WAITBARRIER_GENERIC_HPP