| From | Luis Henriques <> | Subject | [PATCH 3.11 145/208] mm: clear pmd_numa before invalidating | Date | Mon, 13 Jan 2014 15:59:46 +0000 |
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3.11.10.3 -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: Luis Henriques <luis.henriques@canonical.com> --- mm/pgtable-generic.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c index e1a6e4f..0e083c5 100644 --- a/mm/pgtable-generic.c +++ b/mm/pgtable-generic.c @@ -167,6 +167,9 @@ pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp) 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); } -- 1.8.3.2
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