Patch "mm: clear pmd_numa before invalidating" has been added to the 3.12-stable tree

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This is a note to let you know that I've just added the patch titled

    mm: clear pmd_numa before invalidating

to the 3.12-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mm-clear-pmd_numa-before-invalidating.patch
and it can be found in the queue-3.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From 67f87463d3a3362424efcbe8b40e4772fd34fc61 Mon Sep 17 00:00:00 2001
From: Mel Gorman <mgorman@xxxxxxx>
Date: Wed, 18 Dec 2013 17:08:34 -0800
Subject: mm: clear pmd_numa before invalidating

From: Mel Gorman <mgorman@xxxxxxx>

commit 67f87463d3a3362424efcbe8b40e4772fd34fc61 upstream.

On x86, PMD entries are similar to _PAGE_PROTNONE protection and are
handled as NUMA hinting faults.  The following two page table protection
bits are what defines them

	_PAGE_NUMA:set	_PAGE_PRESENT:clear

A PMD is considered present if any of the _PAGE_PRESENT, _PAGE_PROTNONE,
_PAGE_PSE or _PAGE_NUMA bits are set.  If pmdp_invalidate encounters a
pmd_numa, it clears the present bit leaving _PAGE_NUMA which will be
considered not present by the CPU but present by pmd_present.  The
existing caller of pmdp_invalidate should handle it but it's an
inconsistent state for a PMD.  This patch keeps the state consistent
when calling pmdp_invalidate.

Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: Alex Thorlton <athorlton@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 mm/pgtable-generic.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -191,6 +191,9 @@ pgtable_t pgtable_trans_huge_withdraw(st
 void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 		     pmd_t *pmdp)
 {
+	pmd_t entry = *pmdp;
+	if (pmd_numa(entry))
+		entry = pmd_mknonnuma(entry);
 	set_pmd_at(vma->vm_mm, address, pmdp, pmd_mknotpresent(*pmdp));
 	flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 }


Patches currently in stable-queue which might be from mgorman@xxxxxxx are

queue-3.12/sched-numa-skip-inaccessible-vmas.patch
queue-3.12/mm-clear-pmd_numa-before-invalidating.patch
queue-3.12/mm-numa-ensure-anon_vma-is-locked-to-prevent-parallel-thp-splits.patch
queue-3.12/mm-numa-avoid-unnecessary-work-on-the-failure-path.patch
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