学步园

/*
 * Title:        CloudSim Toolkit
 * Description:  CloudSim (Cloud Simulation) Toolkit for Modeling and Simulation of Clouds
 * Licence:      GPL - http://www.gnu.org/copyleft/gpl.html
 *
 * Copyright (c) 2009-2010, The University of Melbourne, Australia
 */

package org.cloudbus.cloudsim;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.cloudbus.cloudsim.lists.PeList;

/**
 * vm的调度策略（空间和时间）
 * VmScheduler is an abstract class that represents the
 * policy used by a VMM to share processing power among VMs running
 * in a host.
 *
 * @author		Rodrigo N. Calheiros
 * @author		Anton Beloglazov
 * @since		CloudSim Toolkit 1.0
 */
public abstract class VmScheduler {

	/** The peList.每个host有个pe列表*/
	private List<? extends Pe> peList;

	/** The MIPS that are currently allocated to the VMs. 
	 * 记录每个vm分配得到的mips
	 * */
	private Map<String, List<Double>> mipsMap;

	/** The total available mips. */
	private double availableMips;

	/**
	 * Creates a new HostAllocationPolicy.
	 *
	 * @param pelist the pelist
	 *
	 * @pre peList != $null
	 * @post $none
	 */
	public VmScheduler(List<? extends Pe> pelist) {
		setPeList(pelist);
		setMipsMap(new HashMap<String, List<Double>>());
		setAvailableMips(PeList.getTotalMips(getPeList()));
	}

	/**
	 * Allocates PEs for a VM.
	 *
	 * @param vm the vm
	 * @param mipsShare the mips share
	 *
	 * @return $true if this policy allows a new VM in the host, $false otherwise
	 *
	 * @pre $none
	 * @post $none
	 */
	public abstract boolean allocatePesForVm(Vm vm, List<Double> mipsShare);

	/**
	 * Releases PEs allocated to a VM.
	 *
	 * @param vm the vm
	 *
	 * @pre $none
	 * @post $none
	 */
	public abstract void deallocatePesForVm(Vm vm);

	/**
	 * 回收所有vms的mips。
	 * 1、对主机中所有pe操作
	 * 2、每个pe中所有vm操作
	 * Releases PEs allocated to all the VMs.
	 *
	 * @param vm the vm
	 *
	 * @pre $none
	 * @post $none
	 */
	public void deallocatePesForAllVms() {
		getMipsMap().clear();
		setAvailableMips(PeList.getTotalMips(getPeList()));   //一台主机所有的mips
		for (Pe pe : getPeList()) {
			pe.getPeProvisioner().deallocateMipsForAllVms();   //每个pe回收所有mips
		}
	}

	/**
	 * Returns the MIPS share of each Pe that is allocated to a given VM.
	 * 返回特定vm使用的mips列表
	 * @param vm the vm
	 *
	 * @return an array containing the amount of MIPS of each pe that is available to the VM
	 *
	 * @pre $none
	 * @post $none
	 */
	public List<Double> getAllocatedMipsForVm(Vm vm) {
		return getMipsMap().get(vm.getUid());
	}

	/**
	 * Gets the total allocated MIPS for a VM over all the PEs.
	 * 一个vm总共占用的mips
	 * @param vm the vm
	 *
	 * @return the allocated mips for vm
	 */
	public double getTotalAllocatedMipsForVm(Vm vm) {
		double allocated = 0;
		List<Double> mipsMap = getAllocatedMipsForVm(vm);
		if (mipsMap != null) {
			for (double mips : mipsMap) {
				allocated += mips;
			}
		}
		return allocated;
	}

	/**
	 * Returns maximum available MIPS among all the PEs.
	 * 返回所有pe中最大可用MIPS
	 * @return max mips
	 */
	public double getMaxAvailableMips() {
		if (getPeList() == null) {
			Log.printLine("Pe list is empty");
			return 0;
		}

		double max = 0.0;
		for (Pe pe : getPeList()) {
			double tmp = pe.getPeProvisioner().getAvailableMips();
			if (tmp > max) {
				max = tmp;
			}
		}

		return max;
	}

	/**
	 * Returns PE capacity in MIPS.
	 * 第一个pe的mips
	 * @return mips
	 */
	public double getPeCapacity() {
		if (getPeList() == null) {
			Log.printLine("Pe list is empty");
			return 0;
		}
		return getPeList().get(0).getMips();
	}

	/**
	 * Gets the vm list.
	 * vm调度，其实就是host中的pe分配策略
	 * 返回了pe列表
	 * @return the vm list
	 */
	@SuppressWarnings("unchecked")
	public <T extends Pe> List<T> getPeList() {
		return (List<T>) peList;
	}

	/**
	 * Sets the vm list.
	 *
	 * @param peList the pe list
	 */
	protected <T extends Pe> void setPeList(List<T> peList) {
		this.peList = peList;
	}

	/**
	 * Gets the mips map.
	 * 获得所占用pe的列表，pelist
	 * @return the mips map
	 */
	protected Map<String, List<Double>> getMipsMap() {
		return mipsMap;
	}

	/**
	 * Sets the mips map.
	 *
	 * @param mipsMap the mips map
	 */
	protected void setMipsMap(Map<String, List<Double>> mipsMap) {
		this.mipsMap = mipsMap;
	}

	/**
	 * Gets the free mips.
	 *
	 * @return the free mips
	 */
	public double getAvailableMips() {
		return availableMips;
	}

	/**
	 * Sets the free mips.
	 *
	 * @param availableMips the new free mips
	 */
	protected void setAvailableMips(double availableMips) {
		this.availableMips = availableMips;
	}

}