"Kirill A. Shutemov" <[email protected]> writes:
> This patch uses modifed pmdp_invalidate(), that return previous value of pmd, > to transfer dirty and accessed bits. > > Signed-off-by: Kirill A. Shutemov <[email protected]> > --- > fs/proc/task_mmu.c | 8 ++++---- > mm/huge_memory.c | 29 ++++++++++++----------------- > 2 files changed, 16 insertions(+), 21 deletions(-) > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > index f0c8b33d99b1..f2fc1ef5bba2 100644 > --- a/fs/proc/task_mmu.c > +++ b/fs/proc/task_mmu.c ..... > @@ -1965,7 +1955,6 @@ static void __split_huge_pmd_locked(struct > vm_area_struct *vma, pmd_t *pmd, > page_ref_add(page, HPAGE_PMD_NR - 1); > write = pmd_write(*pmd); > young = pmd_young(*pmd); > - dirty = pmd_dirty(*pmd); > soft_dirty = pmd_soft_dirty(*pmd); > > pmdp_huge_split_prepare(vma, haddr, pmd); > @@ -1995,8 +1984,6 @@ static void __split_huge_pmd_locked(struct > vm_area_struct *vma, pmd_t *pmd, > if (soft_dirty) > entry = pte_mksoft_dirty(entry); > } > - if (dirty) > - SetPageDirty(page + i); > pte = pte_offset_map(&_pmd, addr); > BUG_ON(!pte_none(*pte)); > set_pte_at(mm, addr, pte, entry); > @@ -2045,7 +2032,15 @@ static void __split_huge_pmd_locked(struct > vm_area_struct *vma, pmd_t *pmd, > * and finally we write the non-huge version of the pmd entry with > * pmd_populate. > */ > - pmdp_invalidate(vma, haddr, pmd); > + old = pmdp_invalidate(vma, haddr, pmd); > + > + /* > + * Transfer dirty bit using value returned by pmd_invalidate() to be > + * sure we don't race with CPU that can set the bit under us. > + */ > + if (pmd_dirty(old)) > + SetPageDirty(page); > + > pmd_populate(mm, pmd, pgtable); > > if (freeze) { Can we invalidate the pmd early here ? ie, do pmdp_invalidate instead of pmdp_huge_split_prepare() ? -aneesh
