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]> Link: http://lkml.kernel.org/n/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
josf · Dec 11, 2012 · 8d1acce · 8d1acce
1 parent 2c3cf55
commit 8d1acce
Showing 1 changed file with 2 additions and 1 deletion.
diff --git 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