| //===--------------------- TaskPool.cpp -------------------------*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "lldb/Utility/TaskPool.h" |
| |
| #include <cstdint> // for uint32_t |
| #include <queue> // for queue |
| #include <thread> // for thread |
| |
| namespace { |
| class TaskPoolImpl { |
| public: |
| static TaskPoolImpl &GetInstance(); |
| |
| void AddTask(std::function<void()> &&task_fn); |
| |
| private: |
| TaskPoolImpl(); |
| |
| static void Worker(TaskPoolImpl *pool); |
| |
| std::queue<std::function<void()>> m_tasks; |
| std::mutex m_tasks_mutex; |
| uint32_t m_thread_count; |
| }; |
| |
| } // end of anonymous namespace |
| |
| TaskPoolImpl &TaskPoolImpl::GetInstance() { |
| static TaskPoolImpl g_task_pool_impl; |
| return g_task_pool_impl; |
| } |
| |
| void TaskPool::AddTaskImpl(std::function<void()> &&task_fn) { |
| TaskPoolImpl::GetInstance().AddTask(std::move(task_fn)); |
| } |
| |
| TaskPoolImpl::TaskPoolImpl() : m_thread_count(0) {} |
| |
| void TaskPoolImpl::AddTask(std::function<void()> &&task_fn) { |
| static const uint32_t max_threads = std::thread::hardware_concurrency(); |
| |
| std::unique_lock<std::mutex> lock(m_tasks_mutex); |
| m_tasks.emplace(std::move(task_fn)); |
| if (m_thread_count < max_threads) { |
| m_thread_count++; |
| // Note that this detach call needs to happen with the m_tasks_mutex held. |
| // This prevents the thread |
| // from exiting prematurely and triggering a linux libc bug |
| // (https://sourceware.org/bugzilla/show_bug.cgi?id=19951). |
| std::thread(Worker, this).detach(); |
| } |
| } |
| |
| void TaskPoolImpl::Worker(TaskPoolImpl *pool) { |
| while (true) { |
| std::unique_lock<std::mutex> lock(pool->m_tasks_mutex); |
| if (pool->m_tasks.empty()) { |
| pool->m_thread_count--; |
| break; |
| } |
| |
| std::function<void()> f = pool->m_tasks.front(); |
| pool->m_tasks.pop(); |
| lock.unlock(); |
| |
| f(); |
| } |
| } |