void page_fault_helper(struct page_table *pt, int page, int vPage, int vFrame, int flag)
{
int vFlag;
/* get the victim flag */
page_table_get_entry(pt, vPage, &vFrame, &vFlag);
/* check for RW flag */
int rw = (PROT_READ|PROT_WRITE);
if(vFlag == rw)
{
/* write victim from physmem to disk */
disk_write(disk, vPage, &physmem[vFrame*PAGE_SIZE]);
write_count++;
}
/* read from disk to victim frame */
disk_read(disk, page, &physmem[vFrame*PAGE_SIZE]);
read_count++;
/* update page table entries */
page_table_set_entry(pt, page, vFrame, flag);
page_table_set_entry(pt, vPage, 0, 0);
/* update loaded_pages */
loaded_pages[vFrame] = page;
/* Second-Chance clock setting */
if(pageswap == 2 && flag == PROT_READ)
{
clock[vFrame] = 0;
}
}
void page_fault_handler( struct page_table *pt, int page )
{
printf("page_rep_choice=%i\n",page_rep_choice);
int frame,nframes,npages,retframe,bits;
// get max number of pages and frames
nframes = page_table_get_nframes(pt);
npages = page_table_get_npages(pt);
// check if frame number should be page number
if (nframes>=npages){
printf("page fault on page #%d\n",page);
frame = page;
}
// FIFO
else if (nframes<npages){
printf("page fault on page #%d\n",page);
if (page_rep_choice==0){
// RAND
frame = page;
}
else if (page_rep_choice==1){
// FIFO
frame = page % nframes;
}
else if (page_rep_choice==2){
// CUSTOM
frame = page;
}
}
// check permissions
// - no permissions -> read
// - read permissions -> write
// - write permissions -> all
if (bits==0){
page_table_set_entry(pt,page,frame,PROT_READ);
}
else if(bits==1){
page_table_set_entry(pt,page,frame,PROT_WRITE);
}
else{
page_table_set_entry(pt,page,frame,PROT_READ|PROT_WRITE|PROT_EXEC);
}
page_table_get_entry(pt,page,&retframe,&bits);
printf("frame=%i\tbits=%i\n",retframe,bits);
// exit(1);
}
void page_fault_handler( struct page_table *pt, int page )
{
page_faults++;
//printf("page fault on page #%d\n", page);
int frame, bits;
page_table_get_entry(pt, page, &frame, &bits);
if(has_read(bits)) {
//printf("page #%d was written to\n", page);
page_table_set_entry(pt, page, frame, bits|PROT_WRITE);
// DEBUG
// page_table_print(pt);
// sleep(1);
return;
}
int unused_frame = next_unused_frame(pt);
if (unused_frame != NO_UNUSED_FRAMES) {
//printf("frame #%d is unused\n", unused_frame);
swap_page(pt, page, unused_frame);
} else {
page_algo_handler(pt, page);
}
// DEBUG
// page_table_print(pt);
// sleep(1);
}
void swap_page(struct page_table *pt, int in_page, int frame) {
if (ft[frame] != -1) {
int bits, out_page = ft[frame];
page_table_get_entry(pt, out_page, &frame, &bits);
if(has_write(bits)) {
// Memory has been modified - write to disk
disk_write(disk, out_page, &physmem[frame * PAGE_SIZE]);
disk_writes++;
}
page_table_set_entry(pt, out_page, 0, 0);
//printf("swapping frame #%d of page #%d with page #%d\n", frame, out_page, in_page);
}
disk_read(disk, in_page, &physmem[frame * PAGE_SIZE]);
page_table_set_entry(pt, in_page, frame, PROT_READ);
disk_reads++;
// Update frame table
ft[frame] = in_page;
}
void page_fault_handler( struct page_table *pt, int page )
{
fault_counter++;
int flag;
int frame;
/* get frame and flag for the page */
page_table_get_entry(pt, page, &frame, &flag);
//page_table_print_entry(pt,page);
int i;
switch(flag)
{
case 0:
/* check for free frame*/
for(i = 0; i < nframes; i++)
{
if(loaded_pages[i] == -1)
{
/* read from disk to physmem */
page_table_set_entry(pt, page, i, PROT_READ);
disk_read(disk, page, &physmem[i*PAGE_SIZE]);
loaded_pages[i] = page;
read_count++;
//page_table_print_entry(pt,page);
//printf("\n");
return;
}
}
/* variables for victim */
int vFrame, vPage;
/* get the victim frame */
get_swap_frame(&vFrame);
/* set the victim page */
vPage = loaded_pages[vFrame];
/* call the helper to settle the pages */
page_fault_helper(pt, page, vPage, vFrame, PROT_READ);
//print_second_chance();
//page_table_print_entry(pt,page);
//printf("\n");
return;
case PROT_READ:
page_table_set_entry(pt, page, frame, PROT_READ|PROT_WRITE);
//page_table_print_entry(pt,page);
//printf("\n");
if(pageswap == 2)
{
clock[frame] = 1;
}
if(pageswap == 3)
{
clock[frame] = 0;
}
return;
}
printf("page fault on page #%d\n",page);
exit(1);
}
