From: Rik van Riel <riel@xxxxxxxxxx>
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 <riel@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
mm/pgtable-generic.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
Index: tip/mm/pgtable-generic.c
===================================================================
--- tip.orig/mm/pgtable-generic.c
+++ tip/mm/pgtable-generic.c
@@ -88,7 +88,8 @@ pte_t ptep_clear_flush(struct vm_area_st
{
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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