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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:45:59 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:45:59 +0000
commit19fcec84d8d7d21e796c7624e521b60d28ee21ed (patch)
tree42d26aa27d1e3f7c0b8bd3fd14e7d7082f5008dc /src/crimson/os/alienstore/thread_pool.h
parentInitial commit. (diff)
downloadceph-19fcec84d8d7d21e796c7624e521b60d28ee21ed.tar.xz
ceph-19fcec84d8d7d21e796c7624e521b60d28ee21ed.zip
Adding upstream version 16.2.11+ds.upstream/16.2.11+dsupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/crimson/os/alienstore/thread_pool.h')
-rw-r--r--src/crimson/os/alienstore/thread_pool.h132
1 files changed, 132 insertions, 0 deletions
diff --git a/src/crimson/os/alienstore/thread_pool.h b/src/crimson/os/alienstore/thread_pool.h
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+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+#pragma once
+
+#include <atomic>
+#include <condition_variable>
+#include <tuple>
+#include <type_traits>
+#include <boost/lockfree/queue.hpp>
+#include <boost/optional.hpp>
+#include <seastar/core/future.hh>
+#include <seastar/core/gate.hh>
+#include <seastar/core/reactor.hh>
+#include <seastar/core/semaphore.hh>
+#include <seastar/core/sharded.hh>
+
+namespace crimson::os {
+
+struct WorkItem {
+ virtual ~WorkItem() {}
+ virtual void process() = 0;
+};
+
+template<typename Func>
+struct Task final : WorkItem {
+ using T = std::invoke_result_t<Func>;
+ using future_stored_type_t =
+ std::conditional_t<std::is_void_v<T>,
+ seastar::internal::future_stored_type_t<>,
+ seastar::internal::future_stored_type_t<T>>;
+ using futurator_t = seastar::futurize<T>;
+public:
+ explicit Task(Func&& f)
+ : func(std::move(f))
+ {}
+ void process() override {
+ try {
+ if constexpr (std::is_void_v<T>) {
+ func();
+ state.set();
+ } else {
+ state.set(func());
+ }
+ } catch (...) {
+ state.set_exception(std::current_exception());
+ }
+ on_done.write_side().signal(1);
+ }
+ typename futurator_t::type get_future() {
+ return on_done.wait().then([this](size_t) {
+ if (state.failed()) {
+ return futurator_t::make_exception_future(state.get_exception());
+ } else {
+ return futurator_t::from_tuple(state.get_value());
+ }
+ });
+ }
+private:
+ Func func;
+ seastar::future_state<future_stored_type_t> state;
+ seastar::readable_eventfd on_done;
+};
+
+struct SubmitQueue {
+ seastar::semaphore free_slots;
+ seastar::gate pending_tasks;
+ explicit SubmitQueue(size_t num_free_slots)
+ : free_slots(num_free_slots)
+ {}
+ seastar::future<> stop() {
+ return pending_tasks.close();
+ }
+};
+
+/// an engine for scheduling non-seastar tasks from seastar fibers
+class ThreadPool {
+ std::atomic<bool> stopping = false;
+ std::mutex mutex;
+ std::condition_variable cond;
+ std::vector<std::thread> threads;
+ seastar::sharded<SubmitQueue> submit_queue;
+ const size_t queue_size;
+ boost::lockfree::queue<WorkItem*> pending;
+
+ void loop(std::chrono::milliseconds queue_max_wait);
+ bool is_stopping() const {
+ return stopping.load(std::memory_order_relaxed);
+ }
+ static void pin(unsigned cpu_id);
+ seastar::semaphore& local_free_slots() {
+ return submit_queue.local().free_slots;
+ }
+ ThreadPool(const ThreadPool&) = delete;
+ ThreadPool& operator=(const ThreadPool&) = delete;
+public:
+ /**
+ * @param queue_sz the depth of pending queue. before a task is scheduled,
+ * it waits in this queue. we will round this number to
+ * multiple of the number of cores.
+ * @param n_threads the number of threads in this thread pool.
+ * @param cpu the CPU core to which this thread pool is assigned
+ * @note each @c Task has its own crimson::thread::Condition, which possesses
+ * an fd, so we should keep the size of queue under a reasonable limit.
+ */
+ ThreadPool(size_t n_threads, size_t queue_sz, long cpu);
+ ~ThreadPool();
+ seastar::future<> start();
+ seastar::future<> stop();
+ template<typename Func, typename...Args>
+ auto submit(Func&& func, Args&&... args) {
+ auto packaged = [func=std::move(func),
+ args=std::forward_as_tuple(args...)] {
+ return std::apply(std::move(func), std::move(args));
+ };
+ return seastar::with_gate(submit_queue.local().pending_tasks,
+ [packaged=std::move(packaged), this] {
+ return local_free_slots().wait()
+ .then([packaged=std::move(packaged), this] {
+ auto task = new Task{std::move(packaged)};
+ auto fut = task->get_future();
+ pending.push(task);
+ cond.notify_one();
+ return fut.finally([task, this] {
+ local_free_slots().signal();
+ delete task;
+ });
+ });
+ });
+ }
+};
+
+} // namespace crimson::os