On Sun, 25 Mar 2007 23:37:08 -0700 (PDT) David Rientjes <[EMAIL PROTECTED]>
wrote:
> Date: Sun, 25 Mar 2007 23:07:43 -0800
> From: Zachary Amsden <[EMAIL PROTECTED]>
>
> If you actually clear the bit, you need to:
>
> + pte_update_defer(vma->vm_mm, addr, ptep);
>
> The reason is, when updating PTEs, the hypervisor must be notified.
> Using
> atomic operations to do this is fine for all hypervisors I am aware of.
> However, for hypervisors which shadow page tables, if these PTE
> modifications are not trapped, you need a post-modification call to
> fulfill
> the update of the shadow page table.
>
> Cc: Zachary Amsden <[EMAIL PROTECTED]>
> Cc: Hugh Dickins <[EMAIL PROTECTED]>
> Signed-off-by: David Rientjes <[EMAIL PROTECTED]>
> ---
> include/asm-i386/pgtable.h | 26 ++++++++++++++------------
> 1 files changed, 14 insertions(+), 12 deletions(-)
>
> diff --git a/include/asm-i386/pgtable.h b/include/asm-i386/pgtable.h
> --- a/include/asm-i386/pgtable.h
> +++ b/include/asm-i386/pgtable.h
> @@ -287,18 +287,24 @@ do {
> \
> 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);
> + int ret = 0;
> + if (pte_dirty(*ptep))
> + ret = test_and_clear_bit(_PAGE_BIT_DIRTY, &ptep->pte_low);
> + if (ret)
> + pte_update_defer(vma->vm_mm, addr, ptep);
> + return ret;
> }
>
i386 allmodconfig:
include/asm/pgtable.h: In function 'ptep_test_and_clear_dirty':
include/asm/pgtable.h:294: error: dereferencing pointer to incomplete type
include/asm/pgtable.h: In function 'ptep_test_and_clear_young':
include/asm/pgtable.h:306: error: dereferencing pointer to incomplete type
Due to vm_area_struct.
Turning it into a stinky macro fixes it.
diff -puN
include/asm-i386/pgtable.h~i386-use-pte_update_defer-in-ptep_test_and_clear_dirtyyoung-fix
include/asm-i386/pgtable.h
---
a/include/asm-i386/pgtable.h~i386-use-pte_update_defer-in-ptep_test_and_clear_dirtyyoung-fix
+++ a/include/asm-i386/pgtable.h
@@ -284,28 +284,24 @@ do {
\
} while (0)
#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)
-{
- int ret = 0;
- if (pte_dirty(*ptep))
- ret = test_and_clear_bit(_PAGE_BIT_DIRTY, &ptep->pte_low);
- if (ret)
- pte_update_defer(vma->vm_mm, addr, ptep);
- return ret;
-}
+#define ptep_test_and_clear_dirty(vma, addr, ptep) ({ \
+ int ret = 0; \
+ if (pte_dirty(*ptep)) \
+ ret = test_and_clear_bit(_PAGE_BIT_DIRTY, &ptep->pte_low); \
+ if (ret) \
+ pte_update_defer(vma->vm_mm, addr, ptep); \
+ ret; \
+})
#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)
-{
- int ret = 0;
- if (pte_young(*ptep))
- ret = test_and_clear_bit(_PAGE_BIT_ACCESSED, &ptep->pte_low);
- if (ret)
- pte_update_defer(vma->vm_mm, addr, ptep);
- return ret;
-}
+#define ptep_test_and_clear_young(vma, addr, ptep) ({ \
+ int ret = 0; \
+ if (pte_young(*ptep)) \
+ ret = test_and_clear_bit(_PAGE_BIT_ACCESSED, &ptep->pte_low); \
+ if (ret) \
+ pte_update_defer(vma->vm_mm, addr, ptep); \
+ ret; \
+})
/*
* Rules for using ptep_establish: the pte MUST be a user pte, and
_
-
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