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b2863017b1
Summary: This patch moves all posix thread logic to a separate library. The motivation is to allow another environments to easily reuse posix threads. HDFS wraps already posix threads; this split would simplify this code. Test Plan: No new functionality is added to posix Env or the threading library, thus the current tests should suffice.
87 lines
2.6 KiB
C++
87 lines
2.6 KiB
C++
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#pragma once
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#include "rocksdb/env.h"
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#include "util/thread_status_util.h"
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namespace rocksdb {
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class ThreadPool {
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public:
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ThreadPool();
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~ThreadPool();
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void JoinAllThreads();
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void LowerIOPriority();
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void BGThread(size_t thread_id);
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void WakeUpAllThreads();
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void IncBackgroundThreadsIfNeeded(int num);
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void SetBackgroundThreads(int num);
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void StartBGThreads();
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void Schedule(void (*function)(void* arg1), void* arg, void* tag);
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int UnSchedule(void* arg);
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unsigned int GetQueueLen() const {
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return queue_len_.load(std::memory_order_relaxed);
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}
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void SetHostEnv(Env* env) { env_ = env; }
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Env* GetHostEnv() { return env_; }
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// Return true if there is at least one thread needs to terminate.
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bool HasExcessiveThread() {
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return static_cast<int>(bgthreads_.size()) > total_threads_limit_;
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}
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// Return true iff the current thread is the excessive thread to terminate.
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// Always terminate the running thread that is added last, even if there are
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// more than one thread to terminate.
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bool IsLastExcessiveThread(size_t thread_id) {
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return HasExcessiveThread() && thread_id == bgthreads_.size() - 1;
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}
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// Is one of the threads to terminate.
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bool IsExcessiveThread(size_t thread_id) {
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return static_cast<int>(thread_id) >= total_threads_limit_;
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}
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// Return the thread priority.
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// This would allow its member-thread to know its priority.
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Env::Priority GetThreadPriority() { return priority_; }
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// Set the thread priority.
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void SetThreadPriority(Env::Priority priority) { priority_ = priority; }
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static void PthreadCall(const char* label, int result);
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private:
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// Entry per Schedule() call
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struct BGItem {
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void* arg;
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void (*function)(void*);
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void* tag;
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};
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typedef std::deque<BGItem> BGQueue;
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pthread_mutex_t mu_;
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pthread_cond_t bgsignal_;
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int total_threads_limit_;
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std::vector<pthread_t> bgthreads_;
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BGQueue queue_;
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std::atomic_uint queue_len_; // Queue length. Used for stats reporting
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bool exit_all_threads_;
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bool low_io_priority_;
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Env::Priority priority_;
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Env* env_;
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void SetBackgroundThreadsInternal(int num, bool allow_reduce);
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};
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} // namespace rocksdb
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