1 /* 2 * Copyright (c) Facebook, Inc. and its affiliates. 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 <folly/synchronization/ParkingLot.h> 18 19 #include <array> 20 21 namespace folly { 22 namespace parking_lot_detail { 23 bucketFor(uint64_t key)24Bucket& Bucket::bucketFor(uint64_t key) { 25 constexpr size_t const kNumBuckets = kIsMobile ? 256 : 4096; 26 27 // Statically allocating this lets us use this in allocation-sensitive 28 // contexts. This relies on the assumption that std::mutex won't dynamically 29 // allocate memory, which we assume to be the case on Linux and iOS. 30 static Indestructible<std::array<Bucket, kNumBuckets>> gBuckets; 31 return (*gBuckets)[key % kNumBuckets]; 32 } 33 34 std::atomic<uint64_t> idallocator{0}; 35 36 } // namespace parking_lot_detail 37 } // namespace folly 38