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author | Zachary Amsden <zach@vmware.com> | 2006-09-30 23:29:34 -0700 |
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committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-10-01 00:39:34 -0700 |
commit | 25e4df5bae333a06cd2c9b88baf14432652dc9f7 (patch) | |
tree | d1391bf273a3a30cc428fee24a626207f5dc331b | |
parent | 6606c3e0da5360799e07ae24b05080cc85c68e72 (diff) | |
download | linux-3.10-25e4df5bae333a06cd2c9b88baf14432652dc9f7.tar.gz linux-3.10-25e4df5bae333a06cd2c9b88baf14432652dc9f7.tar.bz2 linux-3.10-25e4df5bae333a06cd2c9b88baf14432652dc9f7.zip |
[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>
-rw-r--r-- | include/asm-i386/pgtable.h | 41 |
1 files changed, 28 insertions, 13 deletions
diff --git a/include/asm-i386/pgtable.h b/include/asm-i386/pgtable.h index 541b3e23433..94c87ff4b5a 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. + */ #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); -} + +#define __HAVE_ARCH_PTEP_CLEAR_DIRTY_FLUSH +#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 __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH +#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; \ +}) #define __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm, unsigned long addr, pte_t *ptep, int full) |