diff options
authorZachary Amsden <zach@vmware.com>2006-09-30 23:29:34 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-01 00:39:34 -0700
commit25e4df5bae333a06cd2c9b88baf14432652dc9f7 (patch)
parent6606c3e0da5360799e07ae24b05080cc85c68e72 (diff)
[PATCH] paravirt: combine flush accessed dirty.patch
Remove ptep_test_and_clear_{dirty|young} from i386, and instead use the dominating functions, ptep_clear_flush_{dirty|young}. This allows the TLB page flush to be contained in the same macro, and allows for an eager optimization - if reading the PTE initially returned dirty/accessed, we can assume the fact that no subsequent update to the PTE which cleared accessed / dirty has occurred, as the only way A/D bits can change without holding the page table lock is if a remote processor clears them. This eliminates an extra branch which came from the generic version of the code, as we know that no other CPU could have cleared the A/D bit, so the flush will always be needed. We still export these two defines, even though we do not actually define the macros in the i386 code: #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY The reason for this is that the only use of these functions is within the generic clear_flush functions, and we want a strong guarantee that there are no other users of these functions, so we want to prevent the generic code from defining them for us. Signed-off-by: Zachary Amsden <zach@vmware.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
1 files changed, 28 insertions, 13 deletions
diff --git a/include/asm-i386/pgtable.h b/include/asm-i386/pgtable.h
index 541b3e234335..94c87ff4b5ac 100644
--- a/include/asm-i386/pgtable.h
+++ b/include/asm-i386/pgtable.h
@@ -262,21 +262,36 @@ do { \
} \
} while (0)
+ * We don't actually have these, but we want to advertise them so that
+ * we can encompass the flush here.
+ */
-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);
-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);
+#define ptep_clear_flush_dirty(vma, address, ptep) \
+({ \
+ int __dirty; \
+ __dirty = pte_dirty(*(ptep)); \
+ if (__dirty) { \
+ clear_bit(_PAGE_BIT_DIRTY, &(ptep)->pte_low); \
+ flush_tlb_page(vma, address); \
+ } \
+ __dirty; \
+#define ptep_clear_flush_young(vma, address, ptep) \
+({ \
+ int __young; \
+ __young = pte_young(*(ptep)); \
+ if (__young) { \
+ clear_bit(_PAGE_BIT_ACCESSED, &(ptep)->pte_low); \
+ flush_tlb_page(vma, address); \
+ } \
+ __young; \
static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm, unsigned long addr, pte_t *ptep, int full)

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