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pagingMemTest.c
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pagingMemTest.c
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#include "types.h"
#include "stat.h"
#include "user.h"
#include "syscall.h"
#define PGSIZE 4096
#define DEBUG 0
int
main(int argc, char *argv[]){
#if FIFO
int i, j;
char *arr[14];
char input[10];
// Allocate all remaining 12 physical pages
for (i = 0; i < 12; ++i) {
arr[i] = sbrk(PGSIZE);
printf(1, "arr[%d]=0x%x\n", i, arr[i]);
}
printf(1, "Called sbrk(PGSIZE) 12 times - all physical pages taken.\nPress any key...\n");
gets(input, 10);
/*
Allocate page 15.
This allocation would cause page 0 to move to the swap file, but upon returning
to user space, a PGFLT would occur and pages 0,1 will be hot-swapped.
Afterwards, page 1 is in the swap file, the rest are in memory.
*/
arr[12] = sbrk(PGSIZE);
printf(1, "arr[12]=0x%x\n", arr[12]);
printf(1, "Called sbrk(PGSIZE) for the 13th time, a page fault should occur and one page in swap file.\nPress any key...\n");
gets(input, 10);
/*
Allocate page 16.
This would cause page 2 to move to the swap file, but since it contains the
user stack, it would be hot-swapped with page 3.
Afterwards, pages 1 & 3 are in the swap file, the rest are in memory.
*/
arr[13] = sbrk(PGSIZE);
printf(1, "arr[13]=0x%x\n", arr[13]);
printf(1, "Called sbrk(PGSIZE) for the 14th time, a page fault should occur and two pages in swap file.\nPress any key...\n");
gets(input, 10);
/*
Access page 3, causing a PGFLT, since it is in the swap file. It would be
hot-swapped with page 4. Page 4 is accessed next, so another PGFLT is invoked,
and this process repeats a total of 5 times.
*/
for (i = 0; i < 5; i++) {
for (j = 0; j < PGSIZE; j++)
arr[i][j] = 'k';
}
printf(1, "5 page faults should have occurred.\nPress any key...\n");
gets(input, 10);
if (fork() == 0) {
printf(1, "Child code running.\n");
printf(1, "View statistics for pid %d, then press any key...\n", getpid());
gets(input, 10);
/*
The purpose of this write is to create a PGFLT in the child process, and
verify that it is caught and handled properly.
*/
arr[5][0] = 't';
printf(1, "A page fault should have occurred for page 8.\nPress any key to exit the child code.\n");
gets(input, 10);
exit();
}
else {
wait();
/*
Deallocate all the pages.
*/
sbrk(-14 * PGSIZE);
printf(1, "Deallocated all extra pages.\nPress any key to exit the father code.\n");
gets(input, 10);
}
#elif SCFIFO
int i, j;
char *arr[14];
char input[10];
// TODO delete
printf(1, "myMemTest: testing SCFIFO... \n");
// Allocate all remaining 12 physical pages
for (i = 0; i < 12; ++i) {
arr[i] = sbrk(PGSIZE);
printf(1, "arr[%d]=0x%x\n", i, arr[i]);
}
printf(1, "Called sbrk(PGSIZE) 12 times - all physical pages taken.\nPress any key...\n");
gets(input, 10);
/*
Allocate page 15.
For this allocation, SCFIFO will consider moving page 0 to disk, but because it has been accessed, page 1 will be moved instead.
Afterwards, page 1 is in the swap file, the rest are in memory.
*/
arr[12] = sbrk(PGSIZE);
printf(1, "arr[12]=0x%x\n", arr[12]);
printf(1, "Called sbrk(PGSIZE) for the 13th time, no page fault should occur and one page in swap file.\nPress any key...\n");
gets(input, 10);
/*
Allocate page 16.
For this allocation, SCFIFO will consider moving page 2 to disk, but because it has been accessed, page 3 will be moved instead.
Afterwards, pages 1 & 3 are in the swap file, the rest are in memory.
*/
arr[13] = sbrk(PGSIZE);
printf(1, "arr[13]=0x%x\n", arr[13]);
printf(1, "Called sbrk(PGSIZE) for the 14th time, no page fault should occur and two pages in swap file.\nPress any key...\n");
gets(input, 10);
/*
Access page 3, causing a PGFLT, since it is in the swap file. It would be
hot-swapped with page 4. Page 4 is accessed next, so another PGFLT is invoked,
and this process repeats a total of 5 times.
*/
for (i = 0; i < 5; i++) {
for (j = 0; j < PGSIZE; j++)
arr[i][j] = 'k';
}
printf(1, "5 page faults should have occurred.\nPress any key...\n");
gets(input, 10);
/*
If DEBUG flag is defined as != 0 this is just another example showing
that because SCFIFO doesn't page out accessed pages, no needless page faults occurr.
*/
if(DEBUG){
for (i = 0; i < 5; i++) {
printf(1, "Writing to address 0x%x\n", arr[i]);
arr[i][0] = 'k';
}
//printf(1, "No page faults should have occurred.\nPress any key...\n");
gets(input, 10);
}
if (fork() == 0) {
printf(1, "Child code running.\n");
printf(1, "View statistics for pid %d, then press any key...\n", getpid());
gets(input, 10);
/*
The purpose of this write is to create a PGFLT in the child process, and
verify that it is caught and handled properly.
*/
arr[5][0] = 'k';
printf(1, "A Page fault should have occurred in child proccess.\nPress any key to exit the child code.\n");
gets(input, 10);
exit();
}
else {
wait();
/*
Deallocate all the pages.
*/
sbrk(-14 * PGSIZE);
printf(1, "Deallocated all extra pages.\nPress any key to exit the father code.\n");
gets(input, 10);
}
#elif NFU
int i, j;
char *arr[27];
char input[10];
// TODO delete
printf(1, "myMemTest: testing NFU... \n");
// Allocate all remaining 12 physical pages
for (i = 0; i < 12; ++i) {
arr[i] = sbrk(PGSIZE);
printf(1, "arr[%d]=0x%x\n", i, arr[i]);
}
printf(1, "Called sbrk(PGSIZE) 12 times - all physical pages taken.\nPress any key...\n");
gets(input, 10);
/*
Allocate page 15.
For this allocation, NFU will choose to move to disk the page that hasn't been accessed the longest (in this case page 1).
Afterwards, page 1 is in the swap file, the rest are in memory.
*/
arr[12] = sbrk(PGSIZE);
printf(1, "arr[12]=0x%x\n", arr[12]);
printf(1, "Called sbrk(PGSIZE) for the 13th time, no page fault should occur and one page in swap file.\nPress any key...\n");
gets(input, 10);
/*
Allocate page 16.
For this allocation, NFU will choose to move to disk the page that hasn't been accessed the longest (in this case page 3)
Afterwards, pages 1 & 3 are in the swap file, the rest are in memory.
*/
arr[13] = sbrk(PGSIZE);
printf(1, "arr[13]=0x%x\n", arr[13]);
printf(1, "Called sbrk(PGSIZE) for the 14th time, no page fault should occur and two pages in swap file.\nPress any key...\n");
gets(input, 10);
/*
Access page 3, causing a PGFLT, since it is in the swap file. It would be
hot-swapped with page 4. Page 4 is accessed next, so another PGFLT is invoked,
and this process repeats a total of 5 times.
*/
for (i = 0; i < 5; i++) {
printf(1, "Writing to address 0x%x\n", arr[i]);
for (j = 0; j < PGSIZE; j++){
arr[i][j] = 'k';
}
}
printf(1, "5 page faults should have occurred.\nPress any key...\n");
gets(input, 10);
/*
If DEBUG flag is defined as != 0 this is just another example showing
that because NFU doesn't page out accessed pages, no needless page faults occurr.
*/
if(DEBUG){
for (i = 0; i < 5; i++){
printf(1, "Writing to address 0x%x\n", arr[i]);
arr[i][0] = 'k';
}
//printf(1, "No page faults should have occurred.\nPress any key...\n");
gets(input, 10);
}
if (fork() == 0) {
printf(1, "Child code running.\n");
printf(1, "View statistics for pid %d, then press any key...\n", getpid());
gets(input, 10);
/*
The purpose of this write is to create a PGFLT in the child process, and
verify that it is caught and handled properly.
*/
arr[5][0] = 'k';
//arr[5][0] = 't';
printf(1, "Page faults should have occurred in child proccess.\nPress any key to exit the child code.\n");
gets(input, 10);
exit();
}
else {
wait();
/*
Deallocate all the pages.
*/
sbrk(-14 * PGSIZE);
printf(1, "Deallocated all extra pages.\nPress any key to exit the father code.\n");
gets(input, 10);
}
#else
char* arr[50];
int i = 50;
printf(1, "Commencing user test for default paging policy.\nNo page faults should occur.\n");
for (i = 0; i < 50; i++) {
arr[i] = sbrk(PGSIZE);
printf(1, "arr[%d]=0x%x\n", i, arr[i]);
}
#endif
exit();
}