text: /**
   *    Copyright (C) 2014 MongoDB Inc.
   *
   *    This program is free software: you can redistribute it and/or  modify
   *    it under the terms of the GNU Affero General Public License, version 3,
   *    as published by the Free Software Foundation.
   *
   *    This program is distributed in the hope that it will be useful,
   *    but WITHOUT ANY WARRANTY; without even the implied warranty of
   *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *    GNU Affero General Public License for more details.
   *
   *    You should have received a copy of the GNU Affero General Public License
   *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
   *
   *    As a special exception, the copyright holders give permission to link the
   *    code of portions of this program with the OpenSSL library under certain
   *    conditions as described in each individual source file and distribute
   *    linked combinations including the program with the OpenSSL library. You
   *    must comply with the GNU Affero General Public License in all respects for
   *    all of the code used other than as permitted herein. If you modify file(s)
   *    with this exception, you may extend this exception to your version of the
   *    file(s), but you are not obligated to do so. If you do not wish to do so,
   *    delete this exception statement from your version. If you delete this
   *    exception statement from all source files in the program, then also delete
   *    it in the license file.
   */
  
  #define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kStorage
  
  #include "mongo/platform/basic.h"
  
  #include "mongo/db/storage/mmap_v1/data_file_sync.h"
  
  #include "mongo/db/commands/server_status_metric.h"
  #include "mongo/db/service_context.h"
  #include "mongo/db/instance.h"
  #include "mongo/db/storage/mmap_v1/mmap.h"
  #include "mongo/db/storage/mmap_v1/mmap_v1_options.h"
  #include "mongo/db/storage_options.h"
  #include "mongo/util/exit.h"
  #include "mongo/util/log.h"
  
  namespace mongo {
  
      using std::endl;
  
      DataFileSync dataFileSync;
  
      DataFileSync::DataFileSync()
          : ServerStatusSection( "backgroundFlushing" ),
            _total_time( 0 ),
            _flushes( 0 ),
            _last() {
  
      }
  
      void DataFileSync::run() {
          Client::initThread( name().c_str() );
  
          if (storageGlobalParams.syncdelay == 0) {
              log() << "warning: --syncdelay 0 is not recommended and can have strange performance" << endl;
          }
          else if (storageGlobalParams.syncdelay == 1) {
              log() << "--syncdelay 1" << endl;
          }
          else if (storageGlobalParams.syncdelay != 60) {
              LOG(1) << "--syncdelay " << storageGlobalParams.syncdelay << endl;
          }
          int time_flushing = 0;
          while ( ! inShutdown() ) {
              _diaglog.flush();
              if (storageGlobalParams.syncdelay == 0) {
                  // in case at some point we add an option to change at runtime
                  sleepsecs(5);
                  continue;
              }
  
              sleepmillis((long long) std::max(0.0, (storageGlobalParams.syncdelay * 1000) - time_flushing));
  
              if ( inShutdown() ) {
                  // occasional issue trying to flush during shutdown when sleep interrupted
                  break;
              }
  
              Date_t start = jsTime();
              StorageEngine* storageEngine = getGlobalServiceContext()->getGlobalStorageEngine();
              int numFiles = storageEngine->flushAllFiles( true );
              time_flushing = (jsTime() - start).count();
  
              _flushed(time_flushing);
  
              if( shouldLog(logger::LogSeverity::Debug(1)) || time_flushing >= 10000 ) {
                  log() << "flushing mmaps took " << time_flushing << "ms " << " for " << numFiles << " files" << endl;
              }
          }
      }
  
      BSONObj DataFileSync::generateSection(OperationContext* txn,
                                            const BSONElement& configElement) const {
          if (!running()) {
              return BSONObj();
          }
  
          BSONObjBuilder b;
          b.appendNumber( "flushes" , _flushes );
          b.appendNumber( "total_ms" , _total_time );
          b.appendNumber( "average_ms" , (_flushes ? (_total_time / double(_flushes)) : 0.0) );
          b.appendNumber( "last_ms" , _last_time );
          b.append("last_finished", _last);
          return b.obj();
      }
  
      void DataFileSync::_flushed(int ms) {
          _flushes++;
          _total_time += ms;
          _last_time = ms;
          _last = jsTime();
      }
  
  
      class MemJournalServerStatusMetric : public ServerStatusMetric {
      public:
          MemJournalServerStatusMetric() : ServerStatusMetric(".mem.mapped") {}
          virtual void appendAtLeaf( BSONObjBuilder& b ) const {
              int m = static_cast<int>(MemoryMappedFile::totalMappedLength() / ( 1024 * 1024 ));
              b.appendNumber( "mapped" , m );
  
              if (storageGlobalParams.dur) {
                  m *= 2;
                  b.appendNumber( "mappedWithJournal" , m );
              }
  
          }
  
      } memJournalServerStatusMetric;
  }
  