1 /* 2 * Copyright (C) 2010 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 "atomic.h" 18 #include "base/mutex.h" 19 #include "base/stl_util.h" 20 #include "thread-inl.h" 21 22 namespace art { 23 24 std::vector<Mutex*>* QuasiAtomic::gSwapMutexes = nullptr; 25 26 Mutex* QuasiAtomic::GetSwapMutex(const volatile int64_t* addr) { 27 return (*gSwapMutexes)[(reinterpret_cast<uintptr_t>(addr) >> 3U) % kSwapMutexCount]; 28 } 29 30 void QuasiAtomic::Startup() { 31 if (kNeedSwapMutexes) { 32 gSwapMutexes = new std::vector<Mutex*>; 33 for (size_t i = 0; i < kSwapMutexCount; ++i) { 34 gSwapMutexes->push_back(new Mutex("QuasiAtomic stripe", kSwapMutexesLock)); 35 } 36 } 37 } 38 39 void QuasiAtomic::Shutdown() { 40 if (kNeedSwapMutexes) { 41 STLDeleteElements(gSwapMutexes); 42 delete gSwapMutexes; 43 } 44 } 45 46 int64_t QuasiAtomic::SwapMutexRead64(volatile const int64_t* addr) { 47 MutexLock mu(Thread::Current(), *GetSwapMutex(addr)); 48 return *addr; 49 } 50 51 void QuasiAtomic::SwapMutexWrite64(volatile int64_t* addr, int64_t value) { 52 MutexLock mu(Thread::Current(), *GetSwapMutex(addr)); 53 *addr = value; 54 } 55 56 57 bool QuasiAtomic::SwapMutexCas64(int64_t old_value, int64_t new_value, volatile int64_t* addr) { 58 MutexLock mu(Thread::Current(), *GetSwapMutex(addr)); 59 if (*addr == old_value) { 60 *addr = new_value; 61 return true; 62 } 63 return false; 64 } 65 66 } // namespace art 67
