initial code repo

[stor4nfv.git] / src / ceph / src / common / Finisher.cc

diff --git a/src/ceph/src/common/Finisher.cc b/src/ceph/src/common/Finisher.cc
new file mode 100644 (file)
index 0000000..5be9b04
--- /dev/null
+++ b/src/ceph/src/common/Finisher.cc
@@ -0,0 +1,112 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#include "Finisher.h"
+
+#define dout_subsys ceph_subsys_finisher
+#undef dout_prefix
+#define dout_prefix *_dout << "finisher(" << this << ") "
+
+void Finisher::start()
+{
+  ldout(cct, 10) << __func__ << dendl;
+  finisher_thread.create(thread_name.c_str());
+}
+
+void Finisher::stop()
+{
+  ldout(cct, 10) << __func__ << dendl;
+  finisher_lock.Lock();
+  finisher_stop = true;
+  // we don't have any new work to do, but we want the worker to wake up anyway
+  // to process the stop condition.
+  finisher_cond.Signal();
+  finisher_lock.Unlock();
+  finisher_thread.join(); // wait until the worker exits completely
+  ldout(cct, 10) << __func__ << " finish" << dendl;
+}
+
+void Finisher::wait_for_empty()
+{
+  finisher_lock.Lock();
+  while (!finisher_queue.empty() || finisher_running) {
+    ldout(cct, 10) << "wait_for_empty waiting" << dendl;
+    finisher_empty_wait = true;
+    finisher_empty_cond.Wait(finisher_lock);
+  }
+  ldout(cct, 10) << "wait_for_empty empty" << dendl;
+  finisher_empty_wait = false;
+  finisher_lock.Unlock();
+}
+
+void *Finisher::finisher_thread_entry()
+{
+  finisher_lock.Lock();
+  ldout(cct, 10) << "finisher_thread start" << dendl;
+
+  utime_t start;
+  uint64_t count = 0;
+  while (!finisher_stop) {
+    /// Every time we are woken up, we process the queue until it is empty.
+    while (!finisher_queue.empty()) {
+      // To reduce lock contention, we swap out the queue to process.
+      // This way other threads can submit new contexts to complete while we are working.
+      vector<Context*> ls;
+      list<pair<Context*,int> > ls_rval;
+      ls.swap(finisher_queue);
+      ls_rval.swap(finisher_queue_rval);
+      finisher_running = true;
+      finisher_lock.Unlock();
+      ldout(cct, 10) << "finisher_thread doing " << ls << dendl;
+
+      if (logger) {
+       start = ceph_clock_now();
+       count = ls.size();
+      }
+
+      // Now actually process the contexts.
+      for (vector<Context*>::iterator p = ls.begin();
+          p != ls.end();
+          ++p) {
+       if (*p) {
+         (*p)->complete(0);
+       } else {
+         // When an item is NULL in the finisher_queue, it means
+         // we should instead process an item from finisher_queue_rval,
+         // which has a parameter for complete() other than zero.
+         // This preserves the order while saving some storage.
+         assert(!ls_rval.empty());
+         Context *c = ls_rval.front().first;
+         c->complete(ls_rval.front().second);
+         ls_rval.pop_front();
+       }
+      }
+      ldout(cct, 10) << "finisher_thread done with " << ls << dendl;
+      ls.clear();
+      if (logger) {
+       logger->dec(l_finisher_queue_len, count);
+       logger->tinc(l_finisher_complete_lat, ceph_clock_now() - start);
+      }
+
+      finisher_lock.Lock();
+      finisher_running = false;
+    }
+    ldout(cct, 10) << "finisher_thread empty" << dendl;
+    if (unlikely(finisher_empty_wait))
+      finisher_empty_cond.Signal();
+    if (finisher_stop)
+      break;
+    
+    ldout(cct, 10) << "finisher_thread sleeping" << dendl;
+    finisher_cond.Wait(finisher_lock);
+  }
+  // If we are exiting, we signal the thread waiting in stop(),
+  // otherwise it would never unblock
+  finisher_empty_cond.Signal();
+
+  ldout(cct, 10) << "finisher_thread stop" << dendl;
+  finisher_stop = false;
+  finisher_lock.Unlock();
+  return 0;
+}
+