The patch titled
i386: use pte_update_defer in ptep_test_and_clear_{dirty,young}
has been added to the -mm tree. Its filename is
i386-use-pte_update_defer-in-ptep_test_and_clear_dirtyyoung.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: i386: use pte_update_defer in ptep_test_and_clear_{dirty,young}
From: Zachary Amsden <zach@xxxxxxxxxx>
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 <zach@xxxxxxxxxx>
Cc: Hugh Dickins <hugh@xxxxxxxxxxx>
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/asm-i386/pgtable.h | 26 ++++++++++++++------------
1 file changed, 14 insertions(+), 12 deletions(-)
diff -puN include/asm-i386/pgtable.h~i386-use-pte_update_defer-in-ptep_test_and_clear_dirtyyoung include/asm-i386/pgtable.h
--- a/include/asm-i386/pgtable.h~i386-use-pte_update_defer-in-ptep_test_and_clear_dirtyyoung
+++ a/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;
}
#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);
+ 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;
}
/*
@@ -317,10 +323,8 @@ do { \
({ \
int __dirty; \
__dirty = ptep_test_and_clear_dirty((vma), (address), (ptep)); \
- if (__dirty) { \
- pte_update_defer((vma)->vm_mm, (address), (ptep)); \
+ if (__dirty) \
flush_tlb_page(vma, address); \
- } \
__dirty; \
})
@@ -329,10 +333,8 @@ do { \
({ \
int __young; \
__young = ptep_test_and_clear_young((vma), (address), (ptep)); \
- if (__young) { \
- pte_update_defer((vma)->vm_mm, (address), (ptep)); \
+ if (__young) \
flush_tlb_page(vma, address); \
- } \
__young; \
})
_
Patches currently in -mm which might be from zach@xxxxxxxxxx are
make-struct-vmi_ops-static.patch
make-arch-i386-kernel-vmicvmi_pmd_clear-static.patch
i386-use-pte_update_defer-in-ptep_test_and_clear_dirtyyoung.patch
-
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