AioLinuxScheduler.h

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/*
// $Id: //open/dev/fennel/device/AioLinuxScheduler.h#7 $
// Fennel is a library of data storage and processing components.
// Copyright (C) 2005-2009 The Eigenbase Project
// Copyright (C) 2005-2009 SQLstream, Inc.
// Copyright (C) 2005-2009 LucidEra, Inc.
//
// This program is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 of the License, or (at your option)
// any later version approved by The Eigenbase Project.
//
// 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#ifndef Fennel_AioLinuxScheduler_Included
#define Fennel_AioLinuxScheduler_Included

#ifdef USE_LIBAIO_H

#include "fennel/device/DeviceAccessScheduler.h"
#include "fennel/device/RandomAccessRequest.h"
#include "fennel/common/AtomicCounter.h"
#include "fennel/synch/Thread.h"

#include <vector>
#include <deque>
#include <boost/scoped_array.hpp>

FENNEL_BEGIN_NAMESPACE

class FENNEL_DEVICE_EXPORT AioLinuxScheduler
    : public DeviceAccessScheduler, public Thread
{
    io_context_t context;

    AtomicCounter nRequestsOutstanding;

    bool quit;

    std::deque<RandomAccessRequest::BindingList> deferredQueue;

    StrictMutex deferredQueueMutex;

    inline bool isStarted() const;

    bool submitRequests(RandomAccessRequest::BindingList &bindingList);

    void deferLeftoverRequests(
        iocb **ppLeftovers,
        uint nLeftovers);

    bool retryDeferredRequests();

public:
    explicit AioLinuxScheduler(DeviceAccessSchedulerParams const &);

    virtual ~AioLinuxScheduler();

// ----------------------------------------------------------------------
// Implementation of DeviceAccessScheduler interface (q.v.)
// ----------------------------------------------------------------------
    virtual void registerDevice(SharedRandomAccessDevice pDevice);
    virtual bool schedule(RandomAccessRequest &request);
    virtual void stop();

// ----------------------------------------------------------------------
// Implementation of Thread interface (q.v.)
// ----------------------------------------------------------------------
    virtual void run();
};

FENNEL_END_NAMESPACE

#endif

#endif

// End AioLinuxScheduler.h

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