Adding upstream version 18.2.2.upstream/18.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 239 insertions, 0 deletions

diff --git a/src/common/Finisher.h b/src/common/Finisher.h
new file mode 100644
index 000000000..f1060b0e4
--- /dev/null
+++ b/src/common/Finisher.h
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+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*- 
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software 
+ * Foundation.  See file COPYING.
+ * 
+ */
+
+#ifndef CEPH_FINISHER_H
+#define CEPH_FINISHER_H
+
+#include "include/Context.h"
+#include "include/common_fwd.h"
+#include "common/Thread.h"
+#include "common/ceph_mutex.h"
+#include "common/perf_counters.h"
+#include "common/Cond.h"
+
+
+/// Finisher queue length performance counter ID.
+enum {
+  l_finisher_first = 997082,
+  l_finisher_queue_len,
+  l_finisher_complete_lat,
+  l_finisher_last
+};
+
+/** @brief Asynchronous cleanup class.
+ * Finisher asynchronously completes Contexts, which are simple classes
+ * representing callbacks, in a dedicated worker thread. Enqueuing
+ * contexts to complete is thread-safe.
+ */
+class Finisher {
+  CephContext *cct;
+  ceph::mutex finisher_lock; ///< Protects access to queues and finisher_running.
+  ceph::condition_variable finisher_cond; ///< Signaled when there is something to process.
+  ceph::condition_variable finisher_empty_cond; ///< Signaled when the finisher has nothing more to process.
+  bool         finisher_stop; ///< Set when the finisher should stop.
+  bool         finisher_running; ///< True when the finisher is currently executing contexts.
+  bool	       finisher_empty_wait; ///< True mean someone wait finisher empty.
+
+  /// Queue for contexts for which complete(0) will be called.
+  std::vector<std::pair<Context*,int>> finisher_queue;
+  std::vector<std::pair<Context*,int>> in_progress_queue;
+
+  std::string thread_name;
+
+  /// Performance counter for the finisher's queue length.
+  /// Only active for named finishers.
+  PerfCounters *logger;
+
+  void *finisher_thread_entry();
+
+  struct FinisherThread : public Thread {
+    Finisher *fin;
+    explicit FinisherThread(Finisher *f) : fin(f) {}
+    void* entry() override { return fin->finisher_thread_entry(); }
+  } finisher_thread;
+
+ public:
+  /// Add a context to complete, optionally specifying a parameter for the complete function.
+  void queue(Context *c, int r = 0) {
+    std::unique_lock ul(finisher_lock);
+    bool was_empty = finisher_queue.empty();
+    finisher_queue.push_back(std::make_pair(c, r));
+    if (was_empty) {
+      finisher_cond.notify_one();
+    }
+    if (logger)
+      logger->inc(l_finisher_queue_len);
+  }
+
+  void queue(std::list<Context*>& ls) {
+    {
+      std::unique_lock ul(finisher_lock);
+      if (finisher_queue.empty()) {
+	finisher_cond.notify_all();
+      }
+      for (auto i : ls) {
+	finisher_queue.push_back(std::make_pair(i, 0));
+      }
+      if (logger)
+	logger->inc(l_finisher_queue_len, ls.size());
+    }
+    ls.clear();
+  }
+  void queue(std::deque<Context*>& ls) {
+    {
+      std::unique_lock ul(finisher_lock);
+      if (finisher_queue.empty()) {
+	finisher_cond.notify_all();
+      }
+      for (auto i : ls) {
+	finisher_queue.push_back(std::make_pair(i, 0));
+      }
+      if (logger)
+	logger->inc(l_finisher_queue_len, ls.size());
+    }
+    ls.clear();
+  }
+  void queue(std::vector<Context*>& ls) {
+    {
+      std::unique_lock ul(finisher_lock);
+      if (finisher_queue.empty()) {
+	finisher_cond.notify_all();
+      }
+      for (auto i : ls) {
+	finisher_queue.push_back(std::make_pair(i, 0));
+      }
+      if (logger)
+	logger->inc(l_finisher_queue_len, ls.size());
+    }
+    ls.clear();
+  }
+
+  /// Start the worker thread.
+  void start();
+
+  /** @brief Stop the worker thread.
+   *
+   * Does not wait until all outstanding contexts are completed.
+   * To ensure that everything finishes, you should first shut down
+   * all sources that can add contexts to this finisher and call
+   * wait_for_empty() before calling stop(). */
+  void stop();
+
+  /** @brief Blocks until the finisher has nothing left to process.
+   * This function will also return when a concurrent call to stop()
+   * finishes, but this class should never be used in this way. */
+  void wait_for_empty();
+
+  /// Construct an anonymous Finisher.
+  /// Anonymous finishers do not log their queue length.
+  explicit Finisher(CephContext *cct_) :
+    cct(cct_), finisher_lock(ceph::make_mutex("Finisher::finisher_lock")),
+    finisher_stop(false), finisher_running(false), finisher_empty_wait(false),
+    thread_name("fn_anonymous"), logger(0),
+    finisher_thread(this) {}
+
+  /// Construct a named Finisher that logs its queue length.
+  Finisher(CephContext *cct_, std::string name, std::string tn) :
+    cct(cct_), finisher_lock(ceph::make_mutex("Finisher::" + name)),
+    finisher_stop(false), finisher_running(false), finisher_empty_wait(false),
+    thread_name(tn), logger(0),
+    finisher_thread(this) {
+    PerfCountersBuilder b(cct, std::string("finisher-") + name,
+			  l_finisher_first, l_finisher_last);
+    b.add_u64(l_finisher_queue_len, "queue_len");
+    b.add_time_avg(l_finisher_complete_lat, "complete_latency");
+    logger = b.create_perf_counters();
+    cct->get_perfcounters_collection()->add(logger);
+    logger->set(l_finisher_queue_len, 0);
+    logger->set(l_finisher_complete_lat, 0);
+  }
+
+  ~Finisher() {
+    if (logger && cct) {
+      cct->get_perfcounters_collection()->remove(logger);
+      delete logger;
+    }
+  }
+};
+
+/// Context that is completed asynchronously on the supplied finisher.
+class C_OnFinisher : public Context {
+  Context *con;
+  Finisher *fin;
+public:
+  C_OnFinisher(Context *c, Finisher *f) : con(c), fin(f) {
+    ceph_assert(fin != NULL);
+    ceph_assert(con != NULL);
+  }
+
+  ~C_OnFinisher() override {
+    if (con != nullptr) {
+      delete con;
+      con = nullptr;
+    }
+  }
+
+  void finish(int r) override {
+    fin->queue(con, r);
+    con = nullptr;
+  }
+};
+
+class ContextQueue {
+  std::list<Context *> q;
+  std::mutex q_mutex;
+  ceph::mutex& mutex;
+  ceph::condition_variable& cond;
+  std::atomic_bool q_empty = true;
+public:
+  ContextQueue(ceph::mutex& mut,
+	       ceph::condition_variable& con)
+    : mutex(mut), cond(con) {}
+
+  void queue(std::list<Context *>& ls) {
+    bool was_empty = false;
+    {
+      std::scoped_lock l(q_mutex);
+      if (q.empty()) {
+	q.swap(ls);
+	was_empty = true;
+      } else {
+	q.insert(q.end(), ls.begin(), ls.end());
+      }
+      q_empty = q.empty();
+    }
+
+    if (was_empty) {
+      std::scoped_lock l{mutex};
+      cond.notify_all();
+    }
+
+    ls.clear();
+  }
+
+  void move_to(std::list<Context *>& ls) {
+    ls.clear();
+    std::scoped_lock l(q_mutex);
+    if (!q.empty()) {
+      q.swap(ls);
+    }
+    q_empty = true;
+  }
+
+  bool empty() {
+    return q_empty;
+  }
+};
+
+#endif