Commit-ID:  e29be43ba99182dc4f8ec4d305e51e62c8f1e1f9
Gitweb:     http://git.kernel.org/tip/e29be43ba99182dc4f8ec4d305e51e62c8f1e1f9
Author:     Rik van Riel <[email protected]>
AuthorDate: Tue, 9 Oct 2012 15:31:59 +0200
Committer:  Ingo Molnar <[email protected]>
CommitDate: Mon, 19 Nov 2012 02:15:34 +0100

mm: Only flush the TLB when clearing an accessible pte

If ptep_clear_flush() is called to clear a page table entry that is
accessible anyway by the CPU, eg. a _PAGE_PROTNONE page table entry,
there is no need to flush the TLB on remote CPUs.

Signed-off-by: Rik van Riel <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Hugh Dickins <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
 mm/pgtable-generic.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index d8397da..0c8323f 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -88,7 +88,8 @@ pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned 
long address,
 {
        pte_t pte;
        pte = ptep_get_and_clear((vma)->vm_mm, address, ptep);
-       flush_tlb_page(vma, address);
+       if (pte_accessible(pte))
+               flush_tlb_page(vma, address);
        return pte;
 }
 #endif
--
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