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mm: add page_check_address_transhuge() helper

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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>
This commit is contained in:
Vladimir Davydov
2016-01-15 16:54:45 -08:00
committed by Linus Torvalds
parent d965432234
commit 8749cfea11
3 changed files with 144 additions and 143 deletions
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65
mm/page_idle.c
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@@ -55,71 +55,26 @@ static int page_idle_clear_pte_refs_one(struct page *page,
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);
/*