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Commit 10a8d6ae authored by David Rientjes's avatar David Rientjes Committed by Linus Torvalds
Browse files

i386: add ptep_test_and_clear_{dirty,young} 



Add ptep_test_and_clear_{dirty,young} to i386.  They advertise that they
have it and there is at least one place where it needs to be called without
the page table lock: to clear the accessed bit on write to
/proc/pid/clear_refs.

ptep_clear_flush_{dirty,young} are updated to use the new functions.  The
overall net effect to current users of ptep_clear_flush_{dirty,young} is
that we introduce an additional branch.

Cc: Hugh Dickins <hugh@veritas.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 94909914

include/asm-i386/pgtable.h

+17 −8
Original line number Diff line number Diff line
@@ -296,12 +296,23 @@ 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);

}



/*

 * Rules for using ptep_establish: the pte MUST be a user pte, and
@@ -318,9 +329,8 @@ do { \ 
#define ptep_clear_flush_dirty(vma, address, ptep)			\

({									\

	int __dirty;							\

	__dirty = pte_dirty(*(ptep));					\

	__dirty = ptep_test_and_clear_dirty((vma), (address), (ptep));	\

	if (__dirty) {							\

		clear_bit(_PAGE_BIT_DIRTY, &(ptep)->pte_low);		\

		pte_update_defer((vma)->vm_mm, (address), (ptep));	\

		flush_tlb_page(vma, address);				\

	}								\
@@ -331,9 +341,8 @@ do { \ 
#define ptep_clear_flush_young(vma, address, ptep)			\

({									\

	int __young;							\

	__young = pte_young(*(ptep));					\

	__young = ptep_test_and_clear_young((vma), (address), (ptep));	\

	if (__young) {							\

		clear_bit(_PAGE_BIT_ACCESSED, &(ptep)->pte_low);	\

		pte_update_defer((vma)->vm_mm, (address), (ptep));	\

		flush_tlb_page(vma, address);				\

	}								\