| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.10 069/129] mm: clear pmd_numa before invalidating | Date | Mon, 6 Jan 2014 14:38:18 -0800 |
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3.10-stable review patch. If anyone has any objections, please let me know.
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From: Mel Gorman <mgorman@suse.de>
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@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Alex Thorlton <athorlton@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- mm/pgtable-generic.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/mm/pgtable-generic.c +++ b/mm/pgtable-generic.c @@ -166,6 +166,9 @@ 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); }
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