1 | /* |
2 | * Copyright 2017-present Facebook, Inc. |
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 | #include <folly/synchronization/ParkingLot.h> |
17 | |
18 | #include <array> |
19 | |
20 | namespace folly { |
21 | namespace parking_lot_detail { |
22 | |
23 | Bucket& Bucket::bucketFor(uint64_t key) { |
24 | constexpr size_t const kNumBuckets = kIsMobile ? 256 : 4096; |
25 | |
26 | // Statically allocating this lets us use this in allocation-sensitive |
27 | // contexts. This relies on the assumption that std::mutex won't dynamically |
28 | // allocate memory, which we assume to be the case on Linux and iOS. |
29 | static Indestructible<std::array<Bucket, kNumBuckets>> gBuckets; |
30 | return (*gBuckets)[key % kNumBuckets]; |
31 | } |
32 | |
33 | std::atomic<uint64_t> idallocator{0}; |
34 | |
35 | } // namespace parking_lot_detail |
36 | } // namespace folly |
37 | |