/*
- * Copyright 2016 Facebook, Inc.
+ * Copyright 2017 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
// @author Bo Hu (bhu@fb.com)
// @author Jordan DeLong (delong.j@fb.com)
-#ifndef PRODUCER_CONSUMER_QUEUE_H_
-#define PRODUCER_CONSUMER_QUEUE_H_
+#pragma once
#include <atomic>
#include <cassert>
#include <cstdlib>
+#include <memory>
#include <stdexcept>
#include <type_traits>
#include <utility>
+#include <folly/detail/CacheLocality.h>
+
namespace folly {
/*
}
bool isEmpty() const {
- return readIndex_.load(std::memory_order_consume) ==
- writeIndex_.load(std::memory_order_consume);
+ return readIndex_.load(std::memory_order_acquire) ==
+ writeIndex_.load(std::memory_order_acquire);
}
bool isFull() const {
- auto nextRecord = writeIndex_.load(std::memory_order_consume) + 1;
+ auto nextRecord = writeIndex_.load(std::memory_order_acquire) + 1;
if (nextRecord == size_) {
nextRecord = 0;
}
- if (nextRecord != readIndex_.load(std::memory_order_consume)) {
+ if (nextRecord != readIndex_.load(std::memory_order_acquire)) {
return false;
}
// queue is full
// be removing items concurrently).
// * It is undefined to call this from any other thread.
size_t sizeGuess() const {
- int ret = writeIndex_.load(std::memory_order_consume) -
- readIndex_.load(std::memory_order_consume);
+ int ret = writeIndex_.load(std::memory_order_acquire) -
+ readIndex_.load(std::memory_order_acquire);
if (ret < 0) {
ret += size_;
}
}
private:
+ char pad0_[detail::CacheLocality::kFalseSharingRange];
const uint32_t size_;
T* const records_;
- std::atomic<unsigned int> readIndex_;
- std::atomic<unsigned int> writeIndex_;
+ FOLLY_ALIGN_TO_AVOID_FALSE_SHARING std::atomic<unsigned int> readIndex_;
+ FOLLY_ALIGN_TO_AVOID_FALSE_SHARING std::atomic<unsigned int> writeIndex_;
+
+ char pad1_[detail::CacheLocality::kFalseSharingRange - sizeof(writeIndex_)];
};
}
-
-#endif