From: David Rientjes Add ptep_test_and_clear_{dirty,young} to i386. They advertise that they have it and there is at least one place where it needs to be called without the page table lock: to clear the accessed bit on write to /proc/pid/clear_refs. ptep_clear_flush_{dirty,young} are updated to use the new functions. The overall net effect to current users of ptep_clear_flush_{dirty,young} is that we introduce an additional branch. Cc: Hugh Dickins Cc: Ingo Molnar Signed-off-by: David Rientjes Cc: Andi Kleen Signed-off-by: Andrew Morton --- include/asm-i386/pgtable.h | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) diff -puN include/asm-i386/pgtable.h~i386-add-ptep_test_and_clear_dirtyyoung include/asm-i386/pgtable.h --- a/include/asm-i386/pgtable.h~i386-add-ptep_test_and_clear_dirtyyoung +++ a/include/asm-i386/pgtable.h @@ -285,12 +285,23 @@ do { \ } \ } while (0) -/* - * We don't actually have these, but we want to advertise them so that - * we can encompass the flush here. - */ #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY +static inline int ptep_test_and_clear_dirty(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep) +{ + if (!pte_dirty(*ptep)) + return 0; + return test_and_clear_bit(_PAGE_BIT_DIRTY, &ptep->pte_low); +} + #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG +static inline int ptep_test_and_clear_young(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep) +{ + if (!pte_young(*ptep)) + return 0; + return test_and_clear_bit(_PAGE_BIT_ACCESSED, &ptep->pte_low); +} /* * Rules for using ptep_establish: the pte MUST be a user pte, and @@ -307,9 +318,8 @@ do { \ #define ptep_clear_flush_dirty(vma, address, ptep) \ ({ \ int __dirty; \ - __dirty = pte_dirty(*(ptep)); \ + __dirty = ptep_test_and_clear_dirty((vma), (address), (ptep)); \ if (__dirty) { \ - clear_bit(_PAGE_BIT_DIRTY, &(ptep)->pte_low); \ pte_update_defer((vma)->vm_mm, (address), (ptep)); \ flush_tlb_page(vma, address); \ } \ @@ -320,9 +330,8 @@ do { \ #define ptep_clear_flush_young(vma, address, ptep) \ ({ \ int __young; \ - __young = pte_young(*(ptep)); \ + __young = ptep_test_and_clear_young((vma), (address), (ptep)); \ if (__young) { \ - clear_bit(_PAGE_BIT_ACCESSED, &(ptep)->pte_low); \ pte_update_defer((vma)->vm_mm, (address), (ptep)); \ flush_tlb_page(vma, address); \ } \ _