Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=6c210482ae4a9a5bb9377ad250feaacec3faa3cd
Commit:     6c210482ae4a9a5bb9377ad250feaacec3faa3cd
Parent:     2fc2d1e9ffcde78af7ab63ed640d9a4901797de2
Author:     Martin Schwidefsky <[EMAIL PROTECTED]>
AuthorDate: Fri Apr 27 16:01:57 2007 +0200
Committer:  Martin Schwidefsky <[EMAIL PROTECTED]>
CommitDate: Fri Apr 27 16:01:46 2007 +0200

    [S390] split page_test_and_clear_dirty.
    
    The page_test_and_clear_dirty primitive really consists of two
    operations, page_test_dirty and the page_clear_dirty. The combination
    of the two is not an atomic operation, so it makes more sense to have
    two separate operations instead of one.
    In addition to the improved readability of the s390 version of
    SetPageUptodate, it now avoids the page_test_dirty operation which is
    an insert-storage-key-extended (iske) instruction which is an expensive
    operation.
    
    Signed-off-by: Martin Schwidefsky <[EMAIL PROTECTED]>
---
 include/asm-generic/pgtable.h |   11 +++++++++--
 include/asm-s390/pgtable.h    |   15 ++++++++-------
 include/linux/page-flags.h    |    2 +-
 mm/rmap.c                     |    8 ++++++--
 4 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 6d7e279..dc8f99e 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -139,8 +139,15 @@ static inline void ptep_set_wrprotect(struct mm_struct 
*mm, unsigned long addres
 #define pte_same(A,B)  (pte_val(A) == pte_val(B))
 #endif
 
-#ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_DIRTY
-#define page_test_and_clear_dirty(page) (0)
+#ifndef __HAVE_ARCH_PAGE_TEST_DIRTY
+#define page_test_dirty(page)          (0)
+#endif
+
+#ifndef __HAVE_ARCH_PAGE_CLEAR_DIRTY
+#define page_clear_dirty(page)         do { } while (0)
+#endif
+
+#ifndef __HAVE_ARCH_PAGE_TEST_DIRTY
 #define pte_maybe_dirty(pte)           pte_dirty(pte)
 #else
 #define pte_maybe_dirty(pte)           (1)
diff --git a/include/asm-s390/pgtable.h b/include/asm-s390/pgtable.h
index 13c1654..8fe8d42 100644
--- a/include/asm-s390/pgtable.h
+++ b/include/asm-s390/pgtable.h
@@ -753,14 +753,14 @@ ptep_establish(struct vm_area_struct *vma,
  * should therefore only be called if it is not mapped in any
  * address space.
  */
-static inline int page_test_and_clear_dirty(struct page *page)
+static inline int page_test_dirty(struct page *page)
 {
-       unsigned long physpage = page_to_phys(page);
-       int skey = page_get_storage_key(physpage);
+       return (page_get_storage_key(page_to_phys(page)) & _PAGE_CHANGED) != 0;
+}
 
-       if (skey & _PAGE_CHANGED)
-               page_set_storage_key(physpage, skey & ~_PAGE_CHANGED);
-       return skey & _PAGE_CHANGED;
+static inline void page_clear_dirty(struct page *page)
+{
+       page_set_storage_key(page_to_phys(page), PAGE_DEFAULT_KEY);
 }
 
 /*
@@ -953,7 +953,8 @@ extern void memmap_init(unsigned long, int, unsigned long, 
unsigned long);
 #define __HAVE_ARCH_PTEP_CLEAR_FLUSH
 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
 #define __HAVE_ARCH_PTE_SAME
-#define __HAVE_ARCH_PAGE_TEST_AND_CLEAR_DIRTY
+#define __HAVE_ARCH_PAGE_TEST_DIRTY
+#define __HAVE_ARCH_PAGE_CLEAR_DIRTY
 #define __HAVE_ARCH_PAGE_TEST_AND_CLEAR_YOUNG
 #include <asm-generic/pgtable.h>
 
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 9cd0d0e..9632659 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -133,7 +133,7 @@
 static inline void SetPageUptodate(struct page *page)
 {
        if (!test_and_set_bit(PG_uptodate, &page->flags))
-               page_test_and_clear_dirty(page);
+               page_clear_dirty(page);
 }
 #else
 #define SetPageUptodate(page)  set_bit(PG_uptodate, &(page)->flags)
diff --git a/mm/rmap.c b/mm/rmap.c
index b82146e..59da5b7 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -498,8 +498,10 @@ int page_mkclean(struct page *page)
                struct address_space *mapping = page_mapping(page);
                if (mapping)
                        ret = page_mkclean_file(mapping, page);
-               if (page_test_and_clear_dirty(page))
+               if (page_test_dirty(page)) {
+                       page_clear_dirty(page);
                        ret = 1;
+               }
        }
 
        return ret;
@@ -605,8 +607,10 @@ void page_remove_rmap(struct page *page, struct 
vm_area_struct *vma)
                 * Leaving it set also helps swapoff to reinstate ptes
                 * faster for those pages still in swapcache.
                 */
-               if (page_test_and_clear_dirty(page))
+               if (page_test_dirty(page)) {
+                       page_clear_dirty(page);
                        set_page_dirty(page);
+               }
                __dec_zone_page_state(page,
                                PageAnon(page) ? NR_ANON_PAGES : 
NR_FILE_MAPPED);
        }
-
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