// 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;
}
int
shmem_remove_entry(struct shmem_struct *shmem, uintptr_t addr) {
return shmem_insert_entry(shmem, addr, 0);
}
