mm: add page_check_address_transhuge() helper
page_referenced_one() and page_idle_clear_pte_refs_one() duplicate the
code for looking up pte of a (possibly transhuge) page. Move this code
to a new helper function, page_check_address_transhuge(), and make the
above mentioned functions use it.
This is just a cleanup, no functional changes are intended.
Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/page_idle.c b/mm/page_idle.c
index 2c553ba..4ea9c4e 100644
--- a/mm/page_idle.c
+++ b/mm/page_idle.c
@@ -55,71 +55,26 @@
unsigned long addr, void *arg)
{
struct mm_struct *mm = vma->vm_mm;
- spinlock_t *ptl;
- pgd_t *pgd;
- pud_t *pud;
pmd_t *pmd;
pte_t *pte;
+ spinlock_t *ptl;
bool referenced = false;
- pgd = pgd_offset(mm, addr);
- if (!pgd_present(*pgd))
+ if (!page_check_address_transhuge(page, mm, addr, &pmd, &pte, &ptl))
return SWAP_AGAIN;
- pud = pud_offset(pgd, addr);
- if (!pud_present(*pud))
- return SWAP_AGAIN;
- pmd = pmd_offset(pud, addr);
- if (pmd_trans_huge(*pmd)) {
- ptl = pmd_lock(mm, pmd);
- if (!pmd_present(*pmd))
- goto unlock_pmd;
- if (unlikely(!pmd_trans_huge(*pmd))) {
- spin_unlock(ptl);
- goto map_pte;
- }
-
- if (pmd_page(*pmd) != page)
- goto unlock_pmd;
-
- referenced = pmdp_clear_young_notify(vma, addr, pmd);
- spin_unlock(ptl);
- goto found;
-unlock_pmd:
- spin_unlock(ptl);
- return SWAP_AGAIN;
- } else {
- pmd_t pmde = *pmd;
-
- barrier();
- if (!pmd_present(pmde) || pmd_trans_huge(pmde))
- return SWAP_AGAIN;
-
- }
-map_pte:
- pte = pte_offset_map(pmd, addr);
- if (!pte_present(*pte)) {
+ if (pte) {
+ referenced = ptep_clear_young_notify(vma, addr, pte);
pte_unmap(pte);
- return SWAP_AGAIN;
+ } else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
+ referenced = pmdp_clear_young_notify(vma, addr, pmd);
+ } else {
+ /* unexpected pmd-mapped page? */
+ WARN_ON_ONCE(1);
}
- ptl = pte_lockptr(mm, pmd);
- spin_lock(ptl);
+ spin_unlock(ptl);
- if (!pte_present(*pte)) {
- pte_unmap_unlock(pte, ptl);
- return SWAP_AGAIN;
- }
-
- /* THP can be referenced by any subpage */
- if (pte_pfn(*pte) - page_to_pfn(page) >= hpage_nr_pages(page)) {
- pte_unmap_unlock(pte, ptl);
- return SWAP_AGAIN;
- }
-
- referenced = ptep_clear_young_notify(vma, addr, pte);
- pte_unmap_unlock(pte, ptl);
-found:
if (referenced) {
clear_page_idle(page);
/*