1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <sys/types.h>
4 #include <unistd.h>
5 #include <string.h>
6 #include <sys/stat.h>
7 #include <fcntl.h>
8 #include <error.h>
9 #include <wait.h>
10 #define PSIZE 2
11 #define total_instruction 10
12 #define frame_num 4
13
14 int Acess_Series[total_instruction];//存访问页面序列
15 struct one_frame {
16 int page_no;
17 char flag;
18 };
19 struct one_frame M_Frame[frame_num];
20 //这里frame_num是给一个进程分配的最大的内存页面数
21 int isExist(int page){
22 int i;
23 for(i = 0; i < frame_num; i++){
24 if(M_Frame[i].page_no==page)
25 return 1;
26 }
27 return 0;
28 };
29 int getPagePtr(int page){
30 int i;
31 for(i = 0; i < frame_num; i++){
32 if(M_Frame[i].page_no==page)
33 return i;
34 }
35 return 0;
36 };
37 void printMsg(int full_ptr){
38 int i;
39 for(i = 0; i < full_ptr; i++){
40 printf("%d ",M_Frame[i].page_no);
41 }
42 printf("\n");
43 }
44
45
46 int main(){
47 int i;
48 //随机产生内存访问页面序列，存于数组Acess_Series[total_instruction]中
49 srand(time(NULL));
50 for(i = 0; i < total_instruction; i++){
51 Acess_Series[i] = rand()%7 + 1;//1 ~ 7
52 }
53 printf("the pages that will be touch:\n");
54 for(i = 0; i < total_instruction; i++){
55 printf("%d ",Acess_Series[i]);
56 }
57 printf(" 最大的内存页面数:%d \n",frame_num);
58 pid_t pid_1,pid_2;
59 if((pid_1=fork()) == -1){
60 printf("error in fork()!");
61 exit(1);
62 }else if(pid_1 == 0){
63 printf("FIFO child pid:%d , my father pid:\n",getpid(),getppid());
64 int full_ptr = 0;
65 int ming_num = 0,que_num = 0;
66 for(i = 0; i < total_instruction; i++){
67 if(isExist(Acess_Series[i])){
68 ming_num++;
69 }else{
70 que_num++;//看M_Frame[]中有无空闲页面，如果有，装入待访问页，并统计缺页情况，缺页次数加1
71 if(full_ptr < frame_num){//isFull(M_Frame)
72 M_Frame[full_ptr].page_no = Acess_Series[i];
73 M_Frame[full_ptr].flag = 'y';
74 full_ptr++;
75 }else{//如果M_Frame[]中的所有页面均被占满，则淘汰M_Frame[0]，装入待访问页，重新调整各页面在数组中的位置。并统计缺页情况，缺页次数加1
76 int j;
77 printf("ss\n");
78 for(j = 1; j < frame_num; j++){
79 M_Frame[j - 1].page_no = M_Frame[j].page_no;
80 M_Frame[j - 1].flag = M_Frame[j].flag;
81 }
82 M_Frame[j - 1].page_no = Acess_Series[i];
83 M_Frame[j - 1].flag = 'y';
84 }
85 }
86 printMsg(full_ptr);
87 }
88 printf("FIFO child end, ming : %d,que : %d.\n",ming_num,que_num);
89 exit(0);
90 }else{
91 if((pid_2=fork()) == -1){
92 printf("error in fork()!");
93 exit(1);
94 }else if(pid_2 == 0){
95 printf("LRU child pid:%d , my father pid:\n",getpid(),getppid());
96 int full_ptr = 0;
97 int ming_num = 0,que_num = 0;
98 for(i = 0; i < total_instruction; i++){
99 if(isExist(Acess_Series[i])){
100 ming_num++;
101 int page_ptr = getPagePtr(Acess_Series[i]);
102 int j;
103 struct one_frame frame_temp;
104 frame_temp.page_no = M_Frame[page_ptr].page_no;
105 frame_temp.flag = M_Frame[page_ptr].flag;
106 for(j = page_ptr+1; j < full_ptr; j++){
107 M_Frame[j - 1].page_no = M_Frame[j].page_no;
108 M_Frame[j - 1].flag = M_Frame[j].flag;
109 }
110 M_Frame[j - 1].page_no = frame_temp.page_no;
111 M_Frame[j - 1].flag = frame_temp.flag;
112 }else{
113 que_num++;//看M_Frame[]中有无空闲页面，如果有，装入待访问页，并统计缺页情况，缺页次数加1
114 if(full_ptr < frame_num){//isFull(M_Frame)
115 M_Frame[full_ptr].page_no = Acess_Series[i];
116 M_Frame[full_ptr].flag = 'y';
117 full_ptr++;
118 }else{//如果M_Frame[]中的所有页面均被占满，则淘汰M_Frame[0]，装入待访问页，重新调整各页面在数组中的位置。并统计缺页情况，缺页次数加1
119 int j;
120 for(j = 1; j < frame_num; j++){
121 M_Frame[j - 1].page_no = M_Frame[j].page_no;
122 M_Frame[j - 1].flag = M_Frame[j].flag;
123 }
124 M_Frame[j - 1].page_no = Acess_Series[i];
125 M_Frame[j - 1].flag = 'y';
126 }
127 }
128 printMsg(full_ptr);
129 }
130 printf("LRU child end, ming : %d,que : %d.\n",ming_num,que_num);
131 exit(0);
132 }else{//等待子进程执行结束，退出。
133 pid_t pid;
134 while(i < PSIZE){
135 if((pid = wait(0)) < 0){
136 printf("error in waitepid.\n");
137 exit(1);
138 }else{
139 printf("child process %d is endreturn.\n",pid);
140 }
141 i++;
142 }
143 exit(0);
144 }
145 }
146 }
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