1/* 2 * Copyright (C) 2012 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include "barrier.h" 18 19#include "base/mutex.h" 20#include "thread.h" 21 22namespace art { 23 24Barrier::Barrier(int count) 25 : count_(count), 26 lock_("GC barrier lock"), 27 condition_("GC barrier condition", lock_) { 28} 29 30void Barrier::Pass(Thread* self) { 31 MutexLock mu(self, lock_); 32 SetCountLocked(self, count_ - 1); 33} 34 35void Barrier::Wait(Thread* self) { 36 Increment(self, -1); 37} 38 39void Barrier::Init(Thread* self, int count) { 40 MutexLock mu(self, lock_); 41 SetCountLocked(self, count); 42} 43 44void Barrier::Increment(Thread* self, int delta) { 45 MutexLock mu(self, lock_); 46 SetCountLocked(self, count_ + delta); 47 48 // Increment the count. If it becomes zero after the increment 49 // then all the threads have already passed the barrier. If 50 // it is non-zero then there is still one or more threads 51 // that have not yet called the Pass function. When the 52 // Pass function is called by the last thread, the count will 53 // be decremented to zero and a Broadcast will be made on the 54 // condition variable, thus waking this up. 55 if (count_ != 0) { 56 condition_.Wait(self); 57 } 58} 59 60void Barrier::Increment(Thread* self, int delta, uint32_t timeout_ms) { 61 MutexLock mu(self, lock_); 62 SetCountLocked(self, count_ + delta); 63 if (count_ != 0) { 64 condition_.TimedWait(self, timeout_ms, 0); 65 } 66} 67 68void Barrier::SetCountLocked(Thread* self, int count) { 69 count_ = count; 70 if (count_ == 0) { 71 condition_.Broadcast(self); 72 } 73} 74 75Barrier::~Barrier() { 76 CHECK(!count_) << "Attempted to destroy barrier with non zero count"; 77} 78 79} // namespace art 80