folly/folly/detail/MemoryIdler.h

/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#pragma once

#include <algorithm>
#include <atomic>
#include <chrono>

#include <folly/detail/Futex.h>
#include <folly/hash/Hash.h>
#include <folly/synchronization/AtomicStruct.h>
#include <folly/system/ThreadId.h>

namespace folly {
namespace detail {

/// MemoryIdler provides helper routines that allow routines to return
/// some assigned memory resources back to the system.  The intended
/// use is that when a thread is waiting for a long time (perhaps it
/// is in a LIFO thread pool and hasn't been needed for a long time)
/// it should release its thread-local malloc caches (both jemalloc and
/// tcmalloc use these for better performance) and unmap the stack pages
/// that contain no useful data.
struct MemoryIdler { … };

} // namespace detail
} // namespace folly