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 @@ -906,13 +906,13 @@ static inline void clear_soft_dirty(struct vm_area_struct *vma, static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma, unsigned long addr, pmd_t *pmdp) { - pmd_t pmd = *pmdp; + pmd_t old, pmd = *pmdp; /* See comment in change_huge_pmd() */ - pmdp_invalidate(vma, addr, pmdp); - if (pmd_dirty(*pmdp)) + old = pmdp_invalidate(vma, addr, pmdp); + if (pmd_dirty(old)) pmd = pmd_mkdirty(pmd); - if (pmd_young(*pmdp)) + if (pmd_young(old)) pmd = pmd_mkyoung(pmd); pmd = pmd_wrprotect(pmd); diff --git a/mm/huge_memory.c b/mm/huge_memory.c index a84909cf20d3..0433e73531bf 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1777,17 +1777,7 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, * pmdp_invalidate() is required to make sure we don't miss * dirty/young flags set by hardware. */ - entry = *pmd; - pmdp_invalidate(vma, addr, pmd); - - /* - * Recover dirty/young flags. It relies on pmdp_invalidate to not - * corrupt them. - */ - if (pmd_dirty(*pmd)) - entry = pmd_mkdirty(entry); - if (pmd_young(*pmd)) - entry = pmd_mkyoung(entry); + entry = pmdp_invalidate(vma, addr, pmd); entry = pmd_modify(entry, newprot); if (preserve_write) @@ -1927,8 +1917,8 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, struct mm_struct *mm = vma->vm_mm; struct page *page; pgtable_t pgtable; - pmd_t _pmd; - bool young, write, dirty, soft_dirty; + pmd_t old, _pmd; + bool young, write, soft_dirty; unsigned long addr; int i; @@ -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) { -- 2.11.0
