RoundRobin.h

/*
 * Copyright (c) 2008-2014, Pedigree Developers
 *
 * Please see the CONTRIB file in the root of the source tree for a full
 * list of contributors.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
#ifndef ROUND_ROBIN_H
#define ROUND_ROBIN_H
#include "pedigree/kernel/Spinlock.h"
#include "pedigree/kernel/process/SchedulingAlgorithm.h"
 
#include <config.h>
 
class Thread;
 
class RoundRobin : public SchedulingAlgorithm {
 public:
  RoundRobin();
 
  virtual ~RoundRobin();
 
  virtual void addThread(Thread* pThread);
 
  virtual void removeThread(Thread* pThread);
 
  virtual Thread* getNext(Thread* pCurrentThread);
 
  virtual bool hasReady();
 
  virtual void threadStatusChanged(Thread* pThread);
 
#if HOSTED && PEDIGREE_HOSTED_SMOKE_TESTS
  static EXPORTED_PUBLIC bool runHostedIntrusiveQueueRegressions(Thread* pThread);
#endif
 
 private:
  static bool isReady(Thread* pThread);
 
  void enqueue(Thread* pThread);
  void unlink(Thread* pThread);
 
  Thread* m_pReadyQueueHeads[MAX_PRIORITIES];
  Thread* m_pReadyQueueTails[MAX_PRIORITIES];
#if PEDIGREE_READY_QUEUE_COUNTS
  size_t m_ReadyQueueCounts[MAX_PRIORITIES];
#endif
 
  Spinlock m_Lock;
};
 
#endif