// swap_out_vma - try unmap pte & move pages into swap active list.
static int
swap_out_vma(struct mm_struct *mm, struct vma_struct *vma, uintptr_t addr, size_t require) {
if (require == 0 || !(addr >= vma->vm_start && addr < vma->vm_end)) {
return 0;
}
uintptr_t end;
size_t free_count = 0;
addr = ROUNDDOWN(addr, PGSIZE), end = ROUNDUP(vma->vm_end, PGSIZE);
while (addr < end && require != 0) {
pte_t *ptep = get_pte(mm->pgdir, addr, 0);
if (ptep == NULL) {
if (get_pud(mm->pgdir, addr, 0) == NULL) {
addr = ROUNDDOWN(addr + PUSIZE, PUSIZE);
}
else if (get_pmd(mm->pgdir, addr, 0) == NULL) {
addr = ROUNDDOWN(addr + PMSIZE, PMSIZE);
}
else {
addr = ROUNDDOWN(addr + PTSIZE, PTSIZE);
}
continue ;
}
if (ptep_present(ptep)) {
struct Page *page = pte2page(*ptep);
assert(!PageReserved(page));
if (ptep_accessed(ptep)) {
ptep_unset_accessed(ptep);
mp_tlb_invalidate(mm->pgdir, addr);
goto try_next_entry;
}
if (!PageSwap(page)) {
if (!swap_page_add(page, 0)) {
goto try_next_entry;
}
swap_active_list_add(page);
}
else if (ptep_dirty(ptep)) {
SetPageDirty(page);
}
swap_entry_t entry = page->index;
swap_duplicate(entry);
page_ref_dec(page);
ptep_copy(ptep, &entry);
mp_tlb_invalidate(mm->pgdir, addr);
mm->swap_address = addr + PGSIZE;
free_count ++, require --;
if ((vma->vm_flags & VM_SHARE) && page_ref(page) == 1) {
uintptr_t shmem_addr = addr - vma->vm_start + vma->shmem_off;
pte_t *sh_ptep = shmem_get_entry(vma->shmem, shmem_addr, 0);
assert(sh_ptep != NULL && ! ptep_invalid(sh_ptep));
if (ptep_present(sh_ptep)) {
shmem_insert_entry(vma->shmem, shmem_addr, entry);
}
}
}
try_next_entry:
addr += PGSIZE;
}
return free_count;
}
static inline void shmem_remove_entry_pte(pte_t * ptep)
{
//TODO
//assert(0);
assert(ptep != NULL);
if (ptep_present(ptep)) {
struct Page *page = pte2page(*ptep);
#ifdef UCONFIG_SWAP
if (!PageSwap(page)) {
if (page_ref_dec(page) == 0) {
free_page(page);
}
} else {
if (ptep_dirty(ptep)) {
SetPageDirty(page);
}
page_ref_dec(page);
}
#else
if (page_ref_dec(page) == 0) {
free_page(page);
}
#endif /* UCONFIG_SWAP */
ptep_unmap(ptep);
} else if (!ptep_invalid(ptep)) {
#ifdef UCONFIG_SWAP
swap_remove_entry(*ptep);
ptep_unmap(ptep);
#else
assert(0);
#endif
}
}
/**
* page_remove_pte - free an Page sturct which is related linear address la
* - and clean(invalidate) pte which is related linear address la
* @param pgdir page directory (not used)
* @param la logical address of the page to be removed
* @param page table entry of the page to be removed
* note: PT is changed, so the TLB need to be invalidate
*/
void
page_remove_pte(pgd_t *pgdir, uintptr_t la, pte_t *ptep) {
if (ptep_present(ptep)) {
struct Page *page = pte2page(*ptep);
if (!PageSwap(page)) {
if (page_ref_dec(page) == 0) {
//Don't free dma pages
if (!PageIO(page))
free_page(page);
}
}
else {
if (ptep_dirty(ptep)) {
SetPageDirty(page);
}
page_ref_dec(page);
}
ptep_unmap(ptep);
mp_tlb_invalidate(pgdir, la);
}
else if (! ptep_invalid(ptep)) {
#ifndef CONFIG_NO_SWAP
swap_remove_entry(*ptep);
#endif
ptep_unmap(ptep);
}
}
// swap_inactive_list_add - add the page to inactive_list
static inline void
swap_inactive_list_add(struct Page *page) {
assert(PageSwap(page));
ClearPageActive(page);
swap_list_t *list = &inactive_list;
list->nr_pages ++;
list_add_before(&(list->swap_list), &(page->swap_link));
}
// swap_page_count - get reference number of swap page frame
int
swap_page_count(struct Page *page) {
if (!PageSwap(page)) {
return 0;
}
size_t offset = swap_offset(page->index);
assert(mem_map[offset] >= 0);
return mem_map[offset];
}
// refill_inactive_scan - try to move page in swap_active_list into swap_inactive_list
void
refill_inactive_scan(void) {
size_t maxscan = nr_active_pages;
list_entry_t *list = &(active_list.swap_list), *le = list_next(list);
while (maxscan -- > 0 && le != list) {
struct Page *page = le2page(le, swap_link);
le = list_next(le);
if (!(PageSwap(page) && PageActive(page))) {
panic("active: wrong swap list.\n");
}
if (page_ref(page) == 0) {
swap_list_del(page);
swap_inactive_list_add(page);
}
}
}
// swap_page_add - set PG_swap flag in page, set page->index = entry, and add page to hash_list.
// - if entry==0, It means ???
static bool
swap_page_add(struct Page *page, swap_entry_t entry) {
assert(!PageSwap(page));
if (entry == 0) {
if ((entry = try_alloc_swap_entry()) == 0) {
return 0;
}
assert(mem_map[swap_offset(entry)] == SWAP_UNUSED);
mem_map[swap_offset(entry)] = 0;
SetPageDirty(page);
}
SetPageSwap(page);
page->index = entry;
list_add(hash_list + entry_hashfn(entry), &(page->page_link));
return 1;
}
// try_alloc_swap_entry - try to alloc a unused swap entry
static swap_entry_t
try_alloc_swap_entry(void) {
static size_t next = 1;
size_t empty = 0, zero = 0, end = next;
do {
switch (mem_map[next]) {
case SWAP_UNUSED:
empty = next;
break;
case 0:
if (zero == 0) {
zero = next;
}
break;
}
if (++ next == max_swap_offset) {
next = 1;
}
} while (empty == 0 && next != end);
swap_entry_t entry = 0;
if (empty != 0) {
entry = (empty << 8);
}
else if (zero != 0) {
entry = (zero << 8);
struct Page *page = swap_hash_find(entry);
assert(page != NULL && PageSwap(page));
swap_list_del(page);
if (page_ref(page) == 0) {
swap_free_page(page);
}
else {
swap_page_del(page);
}
mem_map[zero] = SWAP_UNUSED;
}
static unsigned int failed_counter = 0;
if (entry == 0 && ((++ failed_counter) % 0x1000) == 0) {
warn("swap: try_alloc_swap_entry: failed too many times.\n");
}
return entry;
}
// page_launder - try to move page to swap_active_list OR swap_inactive_list,
// - and call swap_fs_write to swap out pages in swap_inactive_list
int
page_launder(void) {
size_t maxscan = nr_inactive_pages, free_count = 0;
list_entry_t *list = &(inactive_list.swap_list), *le = list_next(list);
while (maxscan -- > 0 && le != list) {
struct Page *page = le2page(le, swap_link);
le = list_next(le);
if (!(PageSwap(page) && !PageActive(page))) {
panic("inactive: wrong swap list.\n");
}
swap_list_del(page);
if (page_ref(page) != 0) {
swap_active_list_add(page);
continue ;
}
swap_entry_t entry = page->index;
if (!try_free_swap_entry(entry)) {
if (PageDirty(page)) {
ClearPageDirty(page);
swap_duplicate(entry);
if (swapfs_write(entry, page) != 0) {
SetPageDirty(page);
}
mem_map[swap_offset(entry)] --;
if (page_ref(page) != 0) {
swap_active_list_add(page);
continue ;
}
if (PageDirty(page)) {
swap_inactive_list_add(page);
continue ;
}
try_free_swap_entry(entry);
}
}
free_count ++;
swap_free_page(page);
}
return free_count;
}
static inline void
shmem_remove_entry_pte(pte_t *ptep) {
assert(ptep != NULL);
if (ptep_present(ptep)) {
struct Page *page = pte2page(*ptep);
if (!PageSwap(page)) {
if (page_ref_dec(page) == 0) {
free_page(page);
}
}
else {
if (ptep_dirty(ptep)) {
SetPageDirty(page);
}
page_ref_dec(page);
}
ptep_unmap(ptep);
}
else if (! ptep_invalid(ptep)) {
swap_remove_entry(*ptep);
ptep_unmap(ptep);
}
}
static inline void
shmem_remove_entry_pte(pte_t *ptep) {
assert(ptep != NULL);
if (*ptep & PTE_P) {
struct Page *page = pte2page(*ptep);
if (!PageSwap(page)) {
if (page_ref_dec(page) == 0) {
free_page(page);
}
}
else {
if (*ptep & PTE_D) {
SetPageDirty(page);
}
page_ref_dec(page);
}
*ptep = 0;
}
else if (*ptep != 0) {
swap_remove_entry(*ptep);
*ptep = 0;
}
}
// check_swap - check the correctness of swap & page replacement algorithm
static void
check_swap(void) {
size_t nr_used_pages_store = nr_used_pages();
size_t slab_allocated_store = slab_allocated();
size_t offset;
for (offset = 2; offset < max_swap_offset; offset ++) {
mem_map[offset] = 1;
}
struct mm_struct *mm = mm_create();
assert(mm != NULL);
extern struct mm_struct *check_mm_struct;
assert(check_mm_struct == NULL);
check_mm_struct = mm;
pgd_t *pgdir = mm->pgdir = init_pgdir_get();
assert(pgdir[PGX(TEST_PAGE)] == 0);
struct vma_struct *vma = vma_create(TEST_PAGE, TEST_PAGE + PTSIZE, VM_WRITE | VM_READ);
assert(vma != NULL);
insert_vma_struct(mm, vma);
struct Page *rp0 = alloc_page(), *rp1 = alloc_page();
assert(rp0 != NULL && rp1 != NULL);
pte_perm_t perm;
ptep_unmap (&perm);
ptep_set_u_write(&perm);
int ret = page_insert(pgdir, rp1, TEST_PAGE, perm);
assert(ret == 0 && page_ref(rp1) == 1);
page_ref_inc(rp1);
ret = page_insert(pgdir, rp0, TEST_PAGE, perm);
assert(ret == 0 && page_ref(rp1) == 1 && page_ref(rp0) == 1);
// check try_alloc_swap_entry
swap_entry_t entry = try_alloc_swap_entry();
assert(swap_offset(entry) == 1);
mem_map[1] = 1;
assert(try_alloc_swap_entry() == 0);
// set rp1, Swap, Active, add to hash_list, active_list
swap_page_add(rp1, entry);
swap_active_list_add(rp1);
assert(PageSwap(rp1));
mem_map[1] = 0;
entry = try_alloc_swap_entry();
assert(swap_offset(entry) == 1);
assert(!PageSwap(rp1));
// check swap_remove_entry
assert(swap_hash_find(entry) == NULL);
mem_map[1] = 2;
swap_remove_entry(entry);
assert(mem_map[1] == 1);
swap_page_add(rp1, entry);
swap_inactive_list_add(rp1);
swap_remove_entry(entry);
assert(PageSwap(rp1));
assert(rp1->index == entry && mem_map[1] == 0);
// check page_launder, move page from inactive_list to active_list
assert(page_ref(rp1) == 1);
assert(nr_active_pages == 0 && nr_inactive_pages == 1);
assert(list_next(&(inactive_list.swap_list)) == &(rp1->swap_link));
page_launder();
assert(nr_active_pages == 1 && nr_inactive_pages == 0);
assert(PageSwap(rp1) && PageActive(rp1));
entry = try_alloc_swap_entry();
assert(swap_offset(entry) == 1);
assert(!PageSwap(rp1) && nr_active_pages == 0);
assert(list_empty(&(active_list.swap_list)));
// set rp1 inactive again
assert(page_ref(rp1) == 1);
swap_page_add(rp1, 0);
assert(PageSwap(rp1) && swap_offset(rp1->index) == 1);
swap_inactive_list_add(rp1);
mem_map[1] = 1;
assert(nr_inactive_pages == 1);
page_ref_dec(rp1);
size_t count = nr_used_pages();
swap_remove_entry(entry);
assert(nr_inactive_pages == 0 && nr_used_pages() == count - 1);
// check swap_out_mm
pte_t *ptep0 = get_pte(pgdir, TEST_PAGE, 0), *ptep1;
assert(ptep0 != NULL && pte2page(*ptep0) == rp0);
ret = swap_out_mm(mm, 0);
assert(ret == 0);
ret = swap_out_mm(mm, 10);
assert(ret == 1 && mm->swap_address == TEST_PAGE + PGSIZE);
ret = swap_out_mm(mm, 10);
assert(ret == 0 && *ptep0 == entry && mem_map[1] == 1);
assert(PageDirty(rp0) && PageActive(rp0) && page_ref(rp0) == 0);
assert(nr_active_pages == 1 && list_next(&(active_list.swap_list)) == &(rp0->swap_link));
// check refill_inactive_scan()
refill_inactive_scan();
assert(!PageActive(rp0) && page_ref(rp0) == 0);
assert(nr_inactive_pages == 1 && list_next(&(inactive_list.swap_list)) == &(rp0->swap_link));
page_ref_inc(rp0);
page_launder();
assert(PageActive(rp0) && page_ref(rp0) == 1);
assert(nr_active_pages == 1 && list_next(&(active_list.swap_list)) == &(rp0->swap_link));
page_ref_dec(rp0);
refill_inactive_scan();
assert(!PageActive(rp0));
// save data in rp0
int i;
for (i = 0; i < PGSIZE; i ++) {
((char *)page2kva(rp0))[i] = (char)i;
}
page_launder();
assert(nr_inactive_pages == 0 && list_empty(&(inactive_list.swap_list)));
assert(mem_map[1] == 1);
rp1 = alloc_page();
assert(rp1 != NULL);
ret = swapfs_read(entry, rp1);
assert(ret == 0);
for (i = 0; i < PGSIZE; i ++) {
assert(((char *)page2kva(rp1))[i] == (char)i);
}
// page fault now
*(char *)(TEST_PAGE) = 0xEF;
rp0 = pte2page(*ptep0);
assert(page_ref(rp0) == 1);
assert(PageSwap(rp0) && PageActive(rp0));
entry = try_alloc_swap_entry();
assert(swap_offset(entry) == 1 && mem_map[1] == SWAP_UNUSED);
assert(!PageSwap(rp0) && nr_active_pages == 0 && nr_inactive_pages == 0);
// clear accessed flag
assert(rp0 == pte2page(*ptep0));
assert(!PageSwap(rp0));
ret = swap_out_mm(mm, 10);
assert(ret == 0);
assert(!PageSwap(rp0) && ptep_present(ptep0));
// change page table
ret = swap_out_mm(mm, 10);
assert(ret == 1);
assert(*ptep0 == entry && page_ref(rp0) == 0 && mem_map[1] == 1);
count = nr_used_pages();
refill_inactive_scan();
page_launder();
assert(count - 1 == nr_used_pages());
ret = swapfs_read(entry, rp1);
assert(ret == 0 && *(char *)(page2kva(rp1)) == (char)0xEF);
free_page(rp1);
// duplictate *ptep0
ptep1 = get_pte(pgdir, TEST_PAGE + PGSIZE, 0);
assert(ptep1 != NULL && ptep_invalid(ptep1));
swap_duplicate(*ptep0);
ptep_copy(ptep1, ptep0);
mp_tlb_invalidate (pgdir, TEST_PAGE + PGSIZE);
// page fault again
// update for copy on write
*(char *)(TEST_PAGE + 1) = 0x88;
*(char *)(TEST_PAGE + PGSIZE) = 0x8F;
*(char *)(TEST_PAGE + PGSIZE + 1) = 0xFF;
assert(pte2page(*ptep0) != pte2page(*ptep1));
assert(*(char *)(TEST_PAGE) == (char)0xEF);
assert(*(char *)(TEST_PAGE + 1) == (char)0x88);
assert(*(char *)(TEST_PAGE + PGSIZE) == (char)0x8F);
assert(*(char *)(TEST_PAGE + PGSIZE + 1) == (char)0xFF);
rp0 = pte2page(*ptep0);
rp1 = pte2page(*ptep1);
assert(!PageSwap(rp0) && PageSwap(rp1) && PageActive(rp1));
entry = try_alloc_swap_entry();
assert(!PageSwap(rp0) && !PageSwap(rp1));
assert(swap_offset(entry) == 1 && mem_map[1] == SWAP_UNUSED);
assert(list_empty(&(active_list.swap_list)));
assert(list_empty(&(inactive_list.swap_list)));
ptep_set_accessed(&perm);
page_insert(pgdir, rp0, TEST_PAGE + PGSIZE, perm);
// check swap_out_mm
*(char *)(TEST_PAGE) = *(char *)(TEST_PAGE + PGSIZE) = 0xEE;
mm->swap_address = TEST_PAGE + PGSIZE * 2;
ret = swap_out_mm(mm, 2);
assert(ret == 0);
assert(ptep_present(ptep0) && ! ptep_accessed(ptep0));
assert(ptep_present(ptep1) && ! ptep_accessed(ptep1));
ret = swap_out_mm(mm, 2);
assert(ret == 2);
assert(mem_map[1] == 2 && page_ref(rp0) == 0);
refill_inactive_scan();
page_launder();
assert(mem_map[1] == 2 && swap_hash_find(entry) == NULL);
// check copy entry
swap_remove_entry(entry);
ptep_unmap(ptep1);
assert(mem_map[1] == 1);
swap_entry_t store;
ret = swap_copy_entry(entry, &store);
assert(ret == -E_NO_MEM);
mem_map[2] = SWAP_UNUSED;
ret = swap_copy_entry(entry, &store);
assert(ret == 0 && swap_offset(store) == 2 && mem_map[2] == 0);
mem_map[2] = 1;
ptep_copy(ptep1, &store);
assert(*(char *)(TEST_PAGE + PGSIZE) == (char)0xEE && *(char *)(TEST_PAGE + PGSIZE + 1)== (char)0x88);
*(char *)(TEST_PAGE + PGSIZE) = 1, *(char *)(TEST_PAGE + PGSIZE + 1) = 2;
assert(*(char *)TEST_PAGE == (char)0xEE && *(char *)(TEST_PAGE + 1) == (char)0x88);
ret = swap_in_page(entry, &rp0);
assert(ret == 0);
ret = swap_in_page(store, &rp1);
assert(ret == 0);
assert(rp1 != rp0);
// free memory
swap_list_del(rp0), swap_list_del(rp1);
swap_page_del(rp0), swap_page_del(rp1);
assert(page_ref(rp0) == 1 && page_ref(rp1) == 1);
assert(nr_active_pages == 0 && list_empty(&(active_list.swap_list)));
assert(nr_inactive_pages == 0 && list_empty(&(inactive_list.swap_list)));
for (i = 0; i < HASH_LIST_SIZE; i ++) {
assert(list_empty(hash_list + i));
}
page_remove(pgdir, TEST_PAGE);
page_remove(pgdir, (TEST_PAGE + PGSIZE));
#if PMXSHIFT != PUXSHIFT
free_page(pa2page(PMD_ADDR(*get_pmd(pgdir, TEST_PAGE, 0))));
#endif
#if PUXSHIFT != PGXSHIFT
free_page(pa2page(PUD_ADDR(*get_pud(pgdir, TEST_PAGE, 0))));
#endif
free_page(pa2page(PGD_ADDR(*get_pgd(pgdir, TEST_PAGE, 0))));
pgdir[PGX(TEST_PAGE)] = 0;
mm->pgdir = NULL;
mm_destroy(mm);
check_mm_struct = NULL;
assert(nr_active_pages == 0 && nr_inactive_pages == 0);
for (offset = 0; offset < max_swap_offset; offset ++) {
mem_map[offset] = SWAP_UNUSED;
}
assert(nr_used_pages_store == nr_used_pages());
assert(slab_allocated_store == slab_allocated());
kprintf("check_swap() succeeded.\n");
}
// swap_page_del - clear PG_swap flag in page, and del page from hash_list.
static void
swap_page_del(struct Page *page) {
assert(PageSwap(page));
ClearPageSwap(page);
list_del(&(page->page_link));
}
// swap_list_del - delete page from the swap list
static inline void
swap_list_del(struct Page *page) {
assert(PageSwap(page));
(PageActive(page) ? &active_list : &inactive_list)->nr_pages --;
list_del(&(page->swap_link));
}
// check_swap - check the correctness of swap & page replacement algorithm
static void
check_swap(void) {
size_t nr_free_pages_store = nr_free_pages();
size_t slab_allocated_store = slab_allocated();
size_t offset;
for (offset = 2; offset < max_swap_offset; offset ++) {
mem_map[offset] = 1;
}
struct mm_struct *mm = mm_create();
assert(mm != NULL);
extern struct mm_struct *check_mm_struct;
assert(check_mm_struct == NULL);
check_mm_struct = mm;
pde_t *pgdir = mm->pgdir = boot_pgdir;
assert(pgdir[0] == 0);
struct vma_struct *vma = vma_create(0, PTSIZE, VM_WRITE | VM_READ);
assert(vma != NULL);
insert_vma_struct(mm, vma);
struct Page *rp0 = alloc_page(), *rp1 = alloc_page();
assert(rp0 != NULL && rp1 != NULL);
uint32_t perm = PTE_U | PTE_W;
int ret = page_insert(pgdir, rp1, 0, perm);
assert(ret == 0 && page_ref(rp1) == 1);
page_ref_inc(rp1);
ret = page_insert(pgdir, rp0, 0, perm);
assert(ret == 0 && page_ref(rp1) == 1 && page_ref(rp0) == 1);
// check try_alloc_swap_entry
swap_entry_t entry = try_alloc_swap_entry();
assert(swap_offset(entry) == 1);
mem_map[1] = 1;
assert(try_alloc_swap_entry() == 0);
// set rp1, Swap, Active, add to hash_list, active_list
swap_page_add(rp1, entry);
swap_active_list_add(rp1);
assert(PageSwap(rp1));
mem_map[1] = 0;
entry = try_alloc_swap_entry();
assert(swap_offset(entry) == 1);
assert(!PageSwap(rp1));
// check swap_remove_entry
assert(swap_hash_find(entry) == NULL);
mem_map[1] = 2;
swap_remove_entry(entry);
assert(mem_map[1] == 1);
swap_page_add(rp1, entry);
swap_inactive_list_add(rp1);
swap_remove_entry(entry);
assert(PageSwap(rp1));
assert(rp1->index == entry && mem_map[1] == 0);
// check page_launder, move page from inactive_list to active_list
assert(page_ref(rp1) == 1);
assert(nr_active_pages == 0 && nr_inactive_pages == 1);
assert(list_next(&(inactive_list.swap_list)) == &(rp1->swap_link));
page_launder();
assert(nr_active_pages == 1 && nr_inactive_pages == 0);
assert(PageSwap(rp1) && PageActive(rp1));
entry = try_alloc_swap_entry();
assert(swap_offset(entry) == 1);
assert(!PageSwap(rp1) && nr_active_pages == 0);
assert(list_empty(&(active_list.swap_list)));
// set rp1 inactive again
assert(page_ref(rp1) == 1);
swap_page_add(rp1, 0);
assert(PageSwap(rp1) && swap_offset(rp1->index) == 1);
swap_inactive_list_add(rp1);
mem_map[1] = 1;
assert(nr_inactive_pages == 1);
page_ref_dec(rp1);
size_t count = nr_free_pages();
swap_remove_entry(entry);
assert(nr_inactive_pages == 0 && nr_free_pages() == count + 1);
// check swap_out_mm
pte_t *ptep0 = get_pte(pgdir, 0, 0), *ptep1;
assert(ptep0 != NULL && pte2page(*ptep0) == rp0);
ret = swap_out_mm(mm, 0);
assert(ret == 0);
ret = swap_out_mm(mm, 10);
assert(ret == 1 && mm->swap_address == PGSIZE);
ret = swap_out_mm(mm, 10);
assert(ret == 0 && *ptep0 == entry && mem_map[1] == 1);
assert(PageDirty(rp0) && PageActive(rp0) && page_ref(rp0) == 0);
assert(nr_active_pages == 1 && list_next(&(active_list.swap_list)) == &(rp0->swap_link));
// check refill_inactive_scan()
refill_inactive_scan();
assert(!PageActive(rp0) && page_ref(rp0) == 0);
assert(nr_inactive_pages == 1 && list_next(&(inactive_list.swap_list)) == &(rp0->swap_link));
page_ref_inc(rp0);
page_launder();
assert(PageActive(rp0) && page_ref(rp0) == 1);
assert(nr_active_pages == 1 && list_next(&(active_list.swap_list)) == &(rp0->swap_link));
page_ref_dec(rp0);
refill_inactive_scan();
assert(!PageActive(rp0));
// save data in rp0
int i;
for (i = 0; i < PGSIZE; i ++) {
((char *)page2kva(rp0))[i] = (char)i;
}
page_launder();
assert(nr_inactive_pages == 0 && list_empty(&(inactive_list.swap_list)));
assert(mem_map[1] == 1);
rp1 = alloc_page();
assert(rp1 != NULL);
ret = swapfs_read(entry, rp1);
assert(ret == 0);
for (i = 0; i < PGSIZE; i ++) {
assert(((char *)page2kva(rp1))[i] == (char)i);
}
// page fault now
*(char *)0 = 0xEF;
rp0 = pte2page(*ptep0);
assert(page_ref(rp0) == 1);
assert(PageSwap(rp0) && PageActive(rp0));
entry = try_alloc_swap_entry();
assert(swap_offset(entry) == 1 && mem_map[1] == SWAP_UNUSED);
assert(!PageSwap(rp0) && nr_active_pages == 0 && nr_inactive_pages == 0);
// clear accessed flag
assert(rp0 == pte2page(*ptep0));
assert(!PageSwap(rp0));
ret = swap_out_mm(mm, 10);
assert(ret == 0);
assert(!PageSwap(rp0) && (*ptep0 & PTE_P));
// change page table
ret = swap_out_mm(mm, 10);
assert(ret == 1);
assert(*ptep0 == entry && page_ref(rp0) == 0 && mem_map[1] == 1);
count = nr_free_pages();
refill_inactive_scan();
page_launder();
assert(count + 1 == nr_free_pages());
ret = swapfs_read(entry, rp1);
assert(ret == 0 && *(char *)(page2kva(rp1)) == (char)0xEF);
free_page(rp1);
// duplictate *ptep0
ptep1 = get_pte(pgdir, PGSIZE, 0);
assert(ptep1 != NULL && *ptep1 == 0);
swap_duplicate(*ptep0);
*ptep1 = *ptep0;
// page fault again
*(char *)0 = 0xFF;
*(char *)(PGSIZE + 1) = 0x88;
assert(pte2page(*ptep0) == pte2page(*ptep1));
rp0 = pte2page(*ptep0);
assert(*(char *)1 == (char)0x88 && *(char *)PGSIZE == (char)0xFF);
assert(page_ref(rp0) == 2 && rp0->index == entry && mem_map[1] == 0);
assert(PageSwap(rp0) && PageActive(rp0));
entry = try_alloc_swap_entry();
assert(swap_offset(entry) == 1 && mem_map[1] == SWAP_UNUSED);
assert(!PageSwap(rp0));
assert(list_empty(&(active_list.swap_list)));
assert(list_empty(&(inactive_list.swap_list)));
// check swap_out_mm
*(char *)0 = *(char *)PGSIZE = 0xEE;
mm->swap_address = PGSIZE * 2;
ret = swap_out_mm(mm, 2);
assert(ret == 0);
assert((*ptep0 & PTE_P) && !(*ptep0 & PTE_A));
assert((*ptep1 & PTE_P) && !(*ptep1 & PTE_A));
ret = swap_out_mm(mm, 2);
assert(ret == 2);
assert(mem_map[1] == 2 && page_ref(rp0) == 0);
refill_inactive_scan();
page_launder();
assert(mem_map[1] == 2 && swap_hash_find(entry) == NULL);
// check copy entry
swap_remove_entry(entry);
*ptep1 = 0;
assert(mem_map[1] == 1);
swap_entry_t store;
ret = swap_copy_entry(entry, &store);
assert(ret == -E_NO_MEM);
mem_map[2] = SWAP_UNUSED;
ret = swap_copy_entry(entry, &store);
assert(ret == 0 && swap_offset(store) == 2 && mem_map[2] == 0);
mem_map[2] = 1;
*ptep1 = store;
assert(*(char *)PGSIZE == (char)0xEE && *(char *)(PGSIZE + 1)== (char)0x88);
*(char *)PGSIZE = 1, *(char *)(PGSIZE + 1) = 2;
assert(*(char *)0 == (char)0xEE && *(char *)1 == (char)0x88);
ret = swap_in_page(entry, &rp0);
assert(ret == 0);
ret = swap_in_page(store, &rp1);
assert(ret == 0);
assert(rp1 != rp0);
// free memory
swap_list_del(rp0), swap_list_del(rp1);
swap_page_del(rp0), swap_page_del(rp1);
assert(page_ref(rp0) == 1 && page_ref(rp1) == 1);
assert(nr_active_pages == 0 && list_empty(&(active_list.swap_list)));
assert(nr_inactive_pages == 0 && list_empty(&(inactive_list.swap_list)));
for (i = 0; i < HASH_LIST_SIZE; i ++) {
assert(list_empty(hash_list + i));
}
page_remove(pgdir, 0);
page_remove(pgdir, PGSIZE);
free_page(pa2page(pgdir[0]));
pgdir[0] = 0;
mm->pgdir = NULL;
mm_destroy(mm);
check_mm_struct = NULL;
assert(nr_active_pages == 0 && nr_inactive_pages == 0);
for (offset = 0; offset < max_swap_offset; offset ++) {
mem_map[offset] = SWAP_UNUSED;
}
assert(nr_free_pages_store == nr_free_pages());
assert(slab_allocated_store == slab_allocated());
cprintf("check_swap() succeeded.\n");
}
//*****************************************************************************
//
//! Writes an EEPROM entry.
//!
//! This function writes the specified ID and data to the next entry available
//! in the active EEPROM page. If the page is full, PageSwap() will be called.
//!
//! \param ucID is the identifier associated with the data.
//!
//! \param usData is the data to be saved for the given ID.
//!
//! \return A value of 0 indicates that the write was successful. A non-zero
//! value indicates a failure.
//
//*****************************************************************************
long
SoftEEPROMWrite(unsigned short ucID, unsigned short usData)
{
unsigned long ulEntry;
long lReturnCode;
//
// Has the EEPROM been initialized? If not, return the error.
//
if(!g_bEEPROMInitialized)
{
//
// Return the proper error.
//
return(ERR_NOT_INIT);
}
//
// Is the ID specified a valid ID? If not, return the error.
//
if(ucID >= NUM_IDS)
{
//
// Return the proper error.
//
return(ERR_ILLEGAL_ID);
}
//
// If the next available entry location is outside of the currently active
// page, then we need to call PageSwap.
//
if(g_pucNextAvailEntry >= (g_pucActivePage + g_ulEEPROMPgSize))
{
//
// Call PageSwap.
//
lReturnCode = PageSwap(g_pucActivePage);
//
// Was there a failure? If so, return the failure code.
//
if(lReturnCode != 0)
{
return(lReturnCode);
}
}
//
// Calculate the entry.
//
ulEntry = (0 | (ucID << 24) | (usData));
//
// Write the entry to the next available spot in the active page.
//
if(PageDataWrite(&ulEntry, g_pucNextAvailEntry, 4))
{
//
// Return the proper error.
//
return(ERR_PG_WRITE);
}
//
// Increment the next available index variable
//
g_pucNextAvailEntry += 4;
//
// Return indicating that no error occurred.
//
return(0);
}
// swap_free_page - call swap_page_del&free_page to generate a free page
static void
swap_free_page(struct Page *page) {
assert(PageSwap(page) && page_ref(page) == 0);
swap_page_del(page);
free_page(page);
}