2 * Copyright 2017 Facebook, Inc.
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
19 #include <folly/detail/CacheLocality.h>
24 class CachelinePadded;
30 bool needsPadding = (sizeof(T) % CacheLocality::kFalseSharingRange != 0)>
31 struct CachelinePaddedImpl;
33 // We need alignas(T) alignas(kFalseSharingRange) for the case where alignof(T)
34 // > alignof(kFalseSharingRange).
36 struct alignas(T) alignas(detail::CacheLocality::kFalseSharingRange)
37 CachelinePaddedImpl<T, /* needsPadding = */ false> {
38 template <typename... Args>
39 explicit CachelinePaddedImpl(Args&&... args)
40 : item(std::forward<Args>(args)...) {}
45 struct alignas(T) alignas(detail::CacheLocality::kFalseSharingRange)
46 CachelinePaddedImpl<T, /* needsPadding = */ true> {
47 template <typename... Args>
48 explicit CachelinePaddedImpl(Args&&... args)
49 : item(std::forward<Args>(args)...) {}
53 [CacheLocality::kFalseSharingRange -
54 sizeof(T) % CacheLocality::kFalseSharingRange];