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Commit 0013572b authored by Zachary Amsden's avatar Zachary Amsden Committed by Linus Torvalds
Browse files

i386: use pte_update_defer in ptep_test_and_clear_{dirty,young} 



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.

Acked-by: default avatarZachary Amsden <zach@vmware.com>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 10a8d6ae

include/asm-i386/pgtable.h

+18 −20
Original line number Diff line number Diff line
@@ -297,22 +297,24 @@ 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)

{

	if (!pte_dirty(*ptep))

		return 0;

	return test_and_clear_bit(_PAGE_BIT_DIRTY, &ptep->pte_low);

}

#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)

{

	if (!pte_young(*ptep))

		return 0;

	return test_and_clear_bit(_PAGE_BIT_ACCESSED, &ptep->pte_low);

}

#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
@@ -330,10 +332,8 @@ 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;							\

})
@@ -342,10 +342,8 @@ 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;							\

})