| 1 | /* |
| 2 | * Copyright 2012-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 | |
| 17 | #pragma once |
| 18 | |
| 19 | #include <thread> |
| 20 | |
| 21 | #include <folly/portability/Asm.h> |
| 22 | |
| 23 | // Some utilities used by AtomicHashArray and AtomicHashMap |
| 24 | // |
| 25 | |
| 26 | namespace folly { |
| 27 | namespace detail { |
| 28 | |
| 29 | template <typename Cond> |
| 30 | void atomic_hash_spin_wait(Cond condition) { |
| 31 | constexpr size_t kPauseLimit = 10000; |
| 32 | for (size_t i = 0; condition(); ++i) { |
| 33 | if (i < kPauseLimit) { |
| 34 | folly::asm_volatile_pause(); |
| 35 | } else { |
| 36 | std::this_thread::yield(); |
| 37 | } |
| 38 | } |
| 39 | } |
| 40 | |
| 41 | } // namespace detail |
| 42 | } // namespace folly |
| 43 | |