[PATCH] mm: rmap.c cleanup
mm/rmap.c:page_referenced_one() and mm/rmap.c:try_to_unmap_one() contain identical code that - takes mm->page_table_lock; - drills through page tables; - checks that correct pte is reached. Coalesce this into page_check_address() Signed-off-by: Nikita Danilov <nikita@clusterfs.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Nikita Danilov
Linus Torvalds
Родитель
119f657c72
Коммит
81b4082dc7
113
mm/rmap.c
113
mm/rmap.c
|
|
@ -242,6 +242,42 @@ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
|
|||
return vma_address(page, vma);
|
||||
}
|
||||
|
||||
/*
|
||||
* Check that @page is mapped at @address into @mm.
|
||||
*
|
||||
* On success returns with mapped pte and locked mm->page_table_lock.
|
||||
*/
|
||||
static pte_t *page_check_address(struct page *page, struct mm_struct *mm,
|
||||
unsigned long address)
|
||||
{
|
||||
pgd_t *pgd;
|
||||
pud_t *pud;
|
||||
pmd_t *pmd;
|
||||
pte_t *pte;
|
||||
|
||||
/*
|
||||
* We need the page_table_lock to protect us from page faults,
|
||||
* munmap, fork, etc...
|
||||
*/
|
||||
spin_lock(&mm->page_table_lock);
|
||||
pgd = pgd_offset(mm, address);
|
||||
if (likely(pgd_present(*pgd))) {
|
||||
pud = pud_offset(pgd, address);
|
||||
if (likely(pud_present(*pud))) {
|
||||
pmd = pmd_offset(pud, address);
|
||||
if (likely(pmd_present(*pmd))) {
|
||||
pte = pte_offset_map(pmd, address);
|
||||
if (likely(pte_present(*pte) &&
|
||||
page_to_pfn(page) == pte_pfn(*pte)))
|
||||
return pte;
|
||||
pte_unmap(pte);
|
||||
}
|
||||
}
|
||||
}
|
||||
spin_unlock(&mm->page_table_lock);
|
||||
return ERR_PTR(-ENOENT);
|
||||
}
|
||||
|
||||
/*
|
||||
* Subfunctions of page_referenced: page_referenced_one called
|
||||
* repeatedly from either page_referenced_anon or page_referenced_file.
|
||||
|
|
@ -251,9 +287,6 @@ static int page_referenced_one(struct page *page,
|
|||
{
|
||||
struct mm_struct *mm = vma->vm_mm;
|
||||
unsigned long address;
|
||||
pgd_t *pgd;
|
||||
pud_t *pud;
|
||||
pmd_t *pmd;
|
||||
pte_t *pte;
|
||||
int referenced = 0;
|
||||
|
||||
|
|
@ -263,39 +296,18 @@ static int page_referenced_one(struct page *page,
|
|||
if (address == -EFAULT)
|
||||
goto out;
|
||||
|
||||
spin_lock(&mm->page_table_lock);
|
||||
pte = page_check_address(page, mm, address);
|
||||
if (!IS_ERR(pte)) {
|
||||
if (ptep_clear_flush_young(vma, address, pte))
|
||||
referenced++;
|
||||
|
||||
pgd = pgd_offset(mm, address);
|
||||
if (!pgd_present(*pgd))
|
||||
goto out_unlock;
|
||||
if (mm != current->mm && !ignore_token && has_swap_token(mm))
|
||||
referenced++;
|
||||
|
||||
pud = pud_offset(pgd, address);
|
||||
if (!pud_present(*pud))
|
||||
goto out_unlock;
|
||||
|
||||
pmd = pmd_offset(pud, address);
|
||||
if (!pmd_present(*pmd))
|
||||
goto out_unlock;
|
||||
|
||||
pte = pte_offset_map(pmd, address);
|
||||
if (!pte_present(*pte))
|
||||
goto out_unmap;
|
||||
|
||||
if (page_to_pfn(page) != pte_pfn(*pte))
|
||||
goto out_unmap;
|
||||
|
||||
if (ptep_clear_flush_young(vma, address, pte))
|
||||
referenced++;
|
||||
|
||||
if (mm != current->mm && !ignore_token && has_swap_token(mm))
|
||||
referenced++;
|
||||
|
||||
(*mapcount)--;
|
||||
|
||||
out_unmap:
|
||||
pte_unmap(pte);
|
||||
out_unlock:
|
||||
spin_unlock(&mm->page_table_lock);
|
||||
(*mapcount)--;
|
||||
pte_unmap(pte);
|
||||
spin_unlock(&mm->page_table_lock);
|
||||
}
|
||||
out:
|
||||
return referenced;
|
||||
}
|
||||
|
|
@ -502,9 +514,6 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma)
|
|||
{
|
||||
struct mm_struct *mm = vma->vm_mm;
|
||||
unsigned long address;
|
||||
pgd_t *pgd;
|
||||
pud_t *pud;
|
||||
pmd_t *pmd;
|
||||
pte_t *pte;
|
||||
pte_t pteval;
|
||||
int ret = SWAP_AGAIN;
|
||||
|
|
@ -515,30 +524,9 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma)
|
|||
if (address == -EFAULT)
|
||||
goto out;
|
||||
|
||||
/*
|
||||
* We need the page_table_lock to protect us from page faults,
|
||||
* munmap, fork, etc...
|
||||
*/
|
||||
spin_lock(&mm->page_table_lock);
|
||||
|
||||
pgd = pgd_offset(mm, address);
|
||||
if (!pgd_present(*pgd))
|
||||
goto out_unlock;
|
||||
|
||||
pud = pud_offset(pgd, address);
|
||||
if (!pud_present(*pud))
|
||||
goto out_unlock;
|
||||
|
||||
pmd = pmd_offset(pud, address);
|
||||
if (!pmd_present(*pmd))
|
||||
goto out_unlock;
|
||||
|
||||
pte = pte_offset_map(pmd, address);
|
||||
if (!pte_present(*pte))
|
||||
goto out_unmap;
|
||||
|
||||
if (page_to_pfn(page) != pte_pfn(*pte))
|
||||
goto out_unmap;
|
||||
pte = page_check_address(page, mm, address);
|
||||
if (IS_ERR(pte))
|
||||
goto out;
|
||||
|
||||
/*
|
||||
* If the page is mlock()d, we cannot swap it out.
|
||||
|
|
@ -604,7 +592,6 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma)
|
|||
|
||||
out_unmap:
|
||||
pte_unmap(pte);
|
||||
out_unlock:
|
||||
spin_unlock(&mm->page_table_lock);
|
||||
out:
|
||||
return ret;
|
||||
|
|
@ -708,7 +695,6 @@ static void try_to_unmap_cluster(unsigned long cursor,
|
|||
}
|
||||
|
||||
pte_unmap(pte);
|
||||
|
||||
out_unlock:
|
||||
spin_unlock(&mm->page_table_lock);
|
||||
}
|
||||
|
|
@ -860,3 +846,4 @@ int try_to_unmap(struct page *page)
|
|||
ret = SWAP_SUCCESS;
|
||||
return ret;
|
||||
}
|
||||
|
||||
|
|
|
|||
Загрузка…
Ссылка в новой задаче