static unsigned long clear_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
unsigned long addr, unsigned long end)
{
pte_t *pte;
pte_t ptecont;
do {
pte = pte_offset_map(pmd, addr);
ptecont = *pte;
if (pte_none(ptecont))
continue;
/*
* pte_young is a confusing name, though it AND _PAGE_ACCESSED
* Instead, I think we should call it pte_accessed
*/
if (pte_present(ptecont) && pte_young(ptecont)) {
/*
* The physical page, which this pte points to, has
* been read or written to during this time period.
*/
DEBUG_INFO("[%#016lx - %#016lx], pfn = %#013lx", addr, end, pte_pfn(ptecont));
collect_statistics(pte_pfn(ptecont));
pte_clear_flags(ptecont, _PAGE_ACCESSED);
}
} while (pte++, addr += PAGE_SIZE, addr != end);
return addr;
}
static inline
int callback_page_walk(pte_t *pte, unsigned long addr, unsigned long next_addr, struct mm_walk *walk)
{
if (pte_none(*pte) || !pte_present(*pte)
/* || !pte_young(*pte)
|| pte_special(*pte) */
)
return 0;
proc[(long)walk->private].next_addr = addr;
/* TODO: try pte_mknuma on 3.8 */
*pte = pte_clear_flags(*pte, _PAGE_PRESENT);
spcd_pf_extra++;
return 1;
}
static inline void clear_soft_dirty(struct vm_area_struct *vma,
unsigned long addr, pte_t *pte)
{
/*
* The soft-dirty tracker uses #PF-s to catch writes
* to pages, so write-protect the pte as well. See the
* Documentation/vm/soft-dirty.txt for full description
* of how soft-dirty works.
*/
pte_t ptent = *pte;
if (pte_present(ptent)) {
ptent = pte_wrprotect(ptent);
ptent = pte_clear_flags(ptent, _PAGE_SOFT_DIRTY);
} else if (is_swap_pte(ptent)) {
ptent = pte_swp_clear_soft_dirty(ptent);
}
set_pte_at(vma->vm_mm, addr, pte, ptent);
}
static inline void
protect_memory(void)
{
/* Restore kernel memory page protection */
set_pte_atomic(pte, pte_clear_flags(*pte, _PAGE_RW));
}
