sys.h

solutions for some problems in Linux

/******************************************************************************
 * sys.h
 * This file is part of "Assignment 2: Memory Management" 
 * Copyright (C) 2008 - c506001 (email: [e-mail] )
 *
 * Note:
 * -----
 * These codes are used for references, but not complete. Students can modified
 * them to satisfy the requirements.
 * 
 * Content:
 * -------- 
 * The include file: struct System, struct Task
 *
 * System and Networking Department
 * Faculty of Computer Science and Engineering
 * Ho Chi Minh City University of Technology
 ******************************************************************************/

#ifndef __MEM_H__
#define __MEM_H__

#include <stdio.h>

// Declaration format of virtual address
#define N_SECTION_BITS      10	// 10 bits for Page table level 1
#define N_PAGE_BITS         10  // 10 bits for Page table level 2
#define N_OFFSET_BITS       12  // 12 bits for offset (pagesize = 4KB)

#define FREE                0
#define INUSE               1

#define START               0
#define ACCESS              1
#define FINISH              2

#define VALID               1
#define INVALID             0

#define MAX_TASKS           100

#define ERR_NO_FREE_FRAME   (-1)

/**
 * struct PageStatus: management information of page
 * @frame: frame (physical) used for this page
 * @state: state of this page - INVALID / VALID
 **/ 
struct PageStatus {
	int frame;
	int state;
	int lastAccessTime;
};

/**
 * struct PageTable: page table
 * @elems: elements
 **/
struct PageTable {
	struct PageStatus elems[1 << N_PAGE_BITS];
};

/**
 * struct SectionTable: Section table
 * @elems: elements
 **/
struct SectionTable {
	int elems[1 << N_SECTION_BITS];
};

/**
 * struct Task: management information of task. This is the PCB of task.
 **/
struct Task {
	struct Task *next;
	struct Task *prev;
	int pid;
	struct PageTable pageTbl[1 << N_SECTION_BITS];
	struct SectionTable sectionTbl[1];
	int memSize;
};

/**
 * struct TaskList: a list of tasks (2 ways)
 * @first: the pointer to the first task in list
 * @nTasks: the number of tasks in list
 **/ 
struct TaskList{
	struct Task *first;
	int nTasks;
};

/**
 * struct FrameStatus: management information of frame
 * @state: FREE or INUSE
 **/
struct FrameStatus{
	int state;
	int lastAccessTime;
};

/**
 * struct System:
 * @frameStatus: a list of frame-states 
 * @nFrames: the number of elements in frameStatus list
 * @frameSize: usually 4KB.
 * @taskList: list of executable tasks
 **/
struct System {
	struct FrameStatus* frameStatus;    /* FREE or INUSE */
	int nFrames;                        /* constant */
	struct TaskList taskList;
	int clock;
};

int addTask2List(struct TaskList *taskList, struct Task *task);
int removeTask(struct TaskList *taskList, struct Task *task);
struct PageStatus* getFrameFromMem(struct Task *task, int memAddr);
struct PageStatus* getFrameFromPage(struct Task *task, int section, int page);
int updatePage(struct PageStatus *page, int frame, int pid, int memAddr, FILE *outFile);
struct PageStatus *findUnusedPage(struct Task *task);
int initTask(struct Task *task);

int allocFrames4Task(struct System *system, int pid, int memSize, FILE *outFile);
int access2Mem(struct System *system, int pid, int memAddr, FILE *outFile);
int finishTask(struct System *system, int pid, FILE *outFile);
struct PageStatus* chooseVictimFrame(struct System *system, struct Task *task);

#endif