ceph/src/common/Finisher.cc

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3
   4 #include "Finisher.h"
   5
   6 #define dout_subsys ceph_subsys_finisher
   7 #undef dout_prefix
   8 #define dout_prefix *_dout << "finisher(" << this << ") "
   9
  10 void Finisher::start()
  11 {
  12   ldout(cct, 10) << __func__ << dendl;
  13   finisher_thread.create(thread_name.c_str());
  14 }
  15
  16 void Finisher::stop()
  17 {
  18   ldout(cct, 10) << __func__ << dendl;
  19   finisher_lock.lock();
  20   finisher_stop = true;
  21   // we don't have any new work to do, but we want the worker to wake up anyway
  22   // to process the stop condition.
  23   finisher_cond.notify_all();
  24   finisher_lock.unlock();
  25   finisher_thread.join(); // wait until the worker exits completely
  26   ldout(cct, 10) << __func__ << " finish" << dendl;
  27 }
  28
  29 void Finisher::wait_for_empty()
  30 {
  31   std::unique_lock ul(finisher_lock);
  32   while (!finisher_queue.empty() || finisher_running) {
  33     ldout(cct, 10) << "wait_for_empty waiting" << dendl;
  34     finisher_empty_wait = true;
  35     finisher_empty_cond.wait(ul);
  36   }
  37   ldout(cct, 10) << "wait_for_empty empty" << dendl;
  38   finisher_empty_wait = false;
  39 }
  40
  41 void *Finisher::finisher_thread_entry()
  42 {
  43   std::unique_lock ul(finisher_lock);
  44   ldout(cct, 10) << "finisher_thread start" << dendl;
  45
  46   utime_t start;
  47   uint64_t count = 0;
  48   while (!finisher_stop) {
  49     /// Every time we are woken up, we process the queue until it is empty.
  50     while (!finisher_queue.empty()) {
  51       // To reduce lock contention, we swap out the queue to process.
  52       // This way other threads can submit new contexts to complete
  53       // while we are working.
  54       in_progress_queue.swap(finisher_queue);
  55       finisher_running = true;
  56       ul.unlock();
  57       ldout(cct, 10) << "finisher_thread doing " << in_progress_queue << dendl;
  58
  59       if (logger) {
  60         start = ceph_clock_now();
  61         count = in_progress_queue.size();
  62       }
  63
  64       // Now actually process the contexts.
  65       for (auto p : in_progress_queue) {
  66         p.first->complete(p.second);
  67       }
  68       ldout(cct, 10) << "finisher_thread done with " << in_progress_queue
  69                      << dendl;
  70       in_progress_queue.clear();
  71       if (logger) {
  72         logger->dec(l_finisher_queue_len, count);
  73         logger->tinc(l_finisher_complete_lat, ceph_clock_now() - start);
  74       }
  75
  76       ul.lock();
  77       finisher_running = false;
  78     }
  79     ldout(cct, 10) << "finisher_thread empty" << dendl;
  80     if (unlikely(finisher_empty_wait))
  81       finisher_empty_cond.notify_all();
  82     if (finisher_stop)
  83       break;
  84
  85     ldout(cct, 10) << "finisher_thread sleeping" << dendl;
  86     finisher_cond.wait(ul);
  87   }
  88   // If we are exiting, we signal the thread waiting in stop(),
  89   // otherwise it would never unblock
  90   finisher_empty_cond.notify_all();
  91
  92   ldout(cct, 10) << "finisher_thread stop" << dendl;
  93   finisher_stop = false;
  94   return 0;
  95 }
  96