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 <riel@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-vm3rkzevahelwhejx5uwm8ex@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>

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 <riel@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-vm3rkzevahelwhejx5uwm8ex@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Rik van Riel · Mel Gorman
1 parent 2c3cf556b2
Showing 1 changed file with 2 additions and 1 deletions Side-by-side Diff
mm/pgtable-generic.c
@@ -88,7 +88,8 @@
 {
 	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
...	...	@@ -88,7 +88,8 @@
88	88	{
89	89	pte_t pte;
90	90	pte = ptep_get_and_clear((vma)->vm_mm, address, ptep);
91		- flush_tlb_page(vma, address);
	91	+ if (pte_accessible(pte))
	92	+ flush_tlb_page(vma, address);
92	93	return pte;
93	94	}
94	95	#endif