From b4955ce3dd0818b56da532a16c9a4a3804a558ee Mon Sep 17 00:00:00 2001 From: Abhijit Karmarkar Date: Tue, 21 Jun 2005 17:15:13 -0700 Subject: [PATCH] msync: check pte dirty earlier It's common practice to msync a large address range regularly, in which often only a few ptes have actually been dirtied since the previous pass. sync_pte_range then goes much faster if it tests whether pte is dirty before locating and accessing each struct page cacheline; and it is hardly slowed by ptep_clear_flush_dirty repeating that test in the opposite case, when every pte actually is dirty. But beware, s390's pte_dirty always says false, since its dirty bit is kept in the storage key, located via the struct page address. So skip this optimization in its case: use a pte_maybe_dirty macro which just says true if page_test_and_clear_dirty is implemented. Signed-off-by: Abhijit Karmarkar Signed-off-by: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/asm-generic/pgtable.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include') diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index 1f4ec7b70270..f40593565173 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -125,6 +125,9 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres #ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_DIRTY #define page_test_and_clear_dirty(page) (0) +#define pte_maybe_dirty(pte) pte_dirty(pte) +#else +#define pte_maybe_dirty(pte) (1) #endif #ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_YOUNG -- cgit v1.2.3