操作系统实验3：内存分配与回收

今天早上做了操作系统实验：

1、阅读理解两个例程，掌握例程的运作流程。

2、连续式分配例程中提供了三种分配算法：首次适应、循环首次适应、最佳适应。例程还缺少分配作业和回收作业的功能。请至少实现一种分配算法并完成分配作业的功能，保证该例程能够正确实现分配作业的功能

3、回收作业的功能属于选做部分。

4、分页管理例程缺少分配作业和回收的功能，请实现这两个功能，保证该例程能够正确实现分页管理的分配与回收功能

5、上述要求2和4，必须完成其中一个。

 

连续式分配代码贴上：

 

  1 #include <stdio.h>  2 #include <stdlib.h>  3 #include <string.h>  4 #include <time.h>  5   6 #define ret printf("\n")  7 #define spa printf(" ")  8 #define hli printf("-")  9 #define vli printf("    |") 10 #define tab printf("\t") 11 #define capacity 1024          //内存总大小 12 #define max 100              //数组最大长度 13 #define jobsum 8             //作业总数量 14  15  16  17 void _sleep(int n){ 18     clock_t goal; 19     goal = (clock_t)n * CLOCKS_PER_SEC + clock(); 20     while(goal > clock()); 21 } 22  23 char _keygo(){                //按任意键继续 24     char c; 25     printf("Please touch any key to continue....\n"); 26     c = getchar(); 27     return c; 28 } 29  30 typedef struct job JOB;         31 struct job {                //作业结构体 32     int jobid;                //作业ID，系统做东分配，无需输入 33     char name[20];            //作业名称 34     int vol;                //作业大小，即要申请的内存空间大小 35 };                     36  37 JOB jobdata[jobsum] = {        //作业队列 38     {8100, "System", 50}, 39     {8101, "QianQian", 32}, 40     {8102, "XunLei", 128}, 41     {8103, "Dictionary", 76}, 42     {8104, "NorDun", 86}, 43     {10001, "QQ", 168}, 44     {10002, "eMule", 98}, 45     {10003, "Word", 43}, 46 }; 47  48 typedef struct memblock MEM;//内存分区结构 49 struct memblock{ 50     int head;                //地址 51     int length;                //长度 52     int state;                //状态，0表示空闲，1表示占用 53     int jobid;                //已分配，记录作业ID，否则为0 54 }; 55  56 MEM memdata[max] = {        //内存状态表 57     {0, 50, 1, 8100}, 58     {50, 50, 0, 0}, 59     {100, 32, 1, 8101}, 60     {132, 128, 1, 8102}, 61     {260, 100, 0, 0}, 62     {360, 76, 1, 8103}, 63     {436, 200, 0, 0}, 64     {636, 88, 1, 8104}, 65     {724, 300, 0, 0}, 66 }; 67  68 int memsum = 9;                //当前分区总数量，包括已分配分区和空闲分区 69 int curp = 0;                //curp 是位置指针 70  71 MEM membackup[9] = {        //内存状态源数据备份，用于还原 72     {0, 50, 1, 8100}, 73     {50, 50, 0, 0}, 74     {100, 32, 1, 8101}, 75     {132, 128, 1, 8102}, 76     {260, 100, 0, 0}, 77     {360, 76, 1, 8103}, 78     {436, 200, 0, 0}, 79     {636, 88, 1, 8104}, 80     {724, 300, 0, 0}, 81 }; 82  83 int job_locate(int id){        //根据作业ID，查找作业在数组jobdata的位置 84     int i; 85     for(i=0;i<jobsum;++i) 86         if(id == jobdata[i].jobid) 87             return i; 88     return -1; 89 } 90  91 void mem_state(){            //根据memdata数组显示当前内存状态 92     int i, j, k; 93     for(i=0;i<memsum;++i){ 94         tab; 95         printf("%4ik", memdata[i].head); 96         for(j=0;j<20;++j) hli; 97         ret;tab; vli; 98         for(j=0;j<5;++j) spa; 99         if(memdata[i].jobid == 0)100             printf("%10s", "$block$");101         else{102             k = job_locate(memdata[i].jobid);103             printf("%10s", jobdata[k].name);104         }105         vli;ret;106     }107     printf("\t1024k");108     for(j=0;j<20;++j) hli;109     ret;110 }111 112 int mem_allocate_ff(int k){            //首次适应算法113     int i;114     int job_size = jobdata[k].vol;115 116     // for(i=0;i<memsum;++i){117     //     printf("%d %d %d %d\n", memdata[i].head, memdata[i].length, memdata[i].state, memdata[i].jobid);118     // }119     for(i=0;i<memsum;++i){120         if(!memdata[i].state && job_size <= memdata[i].length)121             return i;122     }123     return -1;124 }125 126 127 int mem_allocate_cf(int k){            //循环首次适应算法128     int i;129     int job_size = jobdata[k].vol;130     int t = memsum;131     printf("memsum = %d\n", memsum);132     while(t){133         curp %= memsum;134         i = curp;135         //printf("t : %d curp : %d length: %d state: %d\n", t, curp, memdata[i].length, memdata[i].state);136         if(!memdata[i].state && job_size <= memdata[i].length){137             curp++;138             return i;139         }140         curp++;141         t--;142     }143     return -1;144 }145 146 int mem_allocate_bf(int k){            //最佳适应算法147     int i;148     int job_size = jobdata[k].vol;149     int min = -1;150     for(i=0;i<memsum;++i){151         if(!memdata[i].state && job_size <= memdata[i].length){152             if(min == -1) min = i;153             else if(memdata[i].length<memdata[min].length) min = i;154         }    155     }156     if(min!= -1) return min;157     return -1;158 }159 160 void mem_allocate(int i, int j){    //将分区j分配给作业i161     int k;162 163     if(jobdata[i].vol == memdata[j].length){164         memdata[j].state = 1;165         memdata[j].jobid = jobdata[i].jobid;166     }167     else{168         for(k=memsum-1;k>=j;--k){169             memdata[k+1] = memdata[k];170         }171         int temp = memdata[j].length;172         memdata[j].length = jobdata[i].vol;173 174         memdata[j].state = 1;175         memdata[j].jobid = jobdata[i].jobid;176         memdata[j+1].length = temp - memdata[j].length;177         memdata[j+1].state = 0;178         memdata[j+1].jobid = 0;179         memdata[j+1].head = memdata[j].length + memdata[j].head;180         ++memsum;181     }182 }183 184 int mem_locate(int id){        //根据作业ID，查找jobdata的id在数组memdata的位置185     int i;186     for(i=0;i<memsum;++i)187         if(id == memdata[i].jobid)188             return i;189     return -1;190 }191 192 void mem_redraw(int k){                //作业回收193     int i;194     int t = mem_locate(k);195     printf("t : %d\n", t);196     if(t == -1) return ;197 198     memdata[t].state = 0;199     memdata[t].jobid = 0;200 201     if( t > 0 && memdata[t-1].state == 0 ){202         memdata[t-1].state = 0;203         memdata[t-1].jobid = 0;204         memdata[t-1].length += memdata[t].length;205         for(i=t+1;i<memsum;++i)206             memdata[i-1] = memdata[i];207         --memsum;208         --t;209     }210     if(t+1 <= memsum && memdata[t+1].state == 0){211         memdata[t].state = 0;212         memdata[t].jobid = 0;213         memdata[t].length += memdata[t+1].length;214         for(i=t+2;i<memsum;++i)215             memdata[i-1] = memdata[i];216         --memsum;217     }218 }219 220 void mem_restore(){                    //内存状态还原221     int k;222     memsum = 9;223     for(k=0;k<memsum;++k){224         memdata[k].head = membackup[k-1].head;225         memdata[k].jobid = membackup[k-1].jobid;226         memdata[k].state = membackup[k-1].state;227         memdata[k].length = membackup[k-1].length;228     }229     for(k=memsum;k<max;++k){230         memdata[k].head = 0;231         memdata[k].jobid = 0;232         memdata[k].state = 0;233         memdata[k].length = 0;234     }235 }236 237 int main(int argc, char const *argv[])238 {239     int i, j, start;240     printf("\n------------The current memory state----------!\n");241     mem_state();242     _keygo();243     printf("\n------------The work allocate start-----------!\n");244     start = 5;245     for(i=start;i<jobsum;++i){246         printf("The work %s wait to allocate, The size is %iK\n", jobdata[i].name, jobdata[i].vol);247         _sleep(1);248         j = mem_allocate_ff(i);249         printf("The allocate : %d\n", j);250         if(j == -1) printf("The work %s is too big, the allocation is failed\n", jobdata[i].name);251         else{252             printf("allocation space to The work %s\n", jobdata[i].name);253             mem_allocate(i, j);254             mem_state();255         }256         _keygo();257     }258     printf("----------------The allocation over!---------\n");259     printf("restore the memory!\n");260     printf("\n----------------The current memory state------------\n");261     mem_state();262     j = 88;263     while(j != 0){264         printf("\n Please choose the job No: ");265         scanf("%d", &j);266         mem_redraw(j);267         printf("\nThe restore success !\n");268         printf("\n-------------The current memory state---------\n");269         mem_state();270     }271     _keygo();272     return 0;273 }