| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.10 074/129] mm: numa: guarantee that tlb_flush_pending updates are visible before page table updates | Date | Mon, 6 Jan 2014 14:38:23 -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 af2c1401e6f9177483be4fad876d0073669df9df upstream.
According to documentation on barriers, stores issued before a LOCK can complete after the lock implying that it's possible tlb_flush_pending can be visible after a page table update. As per revised documentation, this patch adds a smp_mb__before_spinlock to guarantee the correct ordering.
Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Rik van Riel <riel@redhat.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>
--- include/linux/mm_types.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
--- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -480,7 +480,12 @@ static inline bool mm_tlb_flush_pending( static inline void set_tlb_flush_pending(struct mm_struct *mm) { mm->tlb_flush_pending = true; - barrier(); + + /* + * Guarantee that the tlb_flush_pending store does not leak into the + * critical section updating the page tables + */ + smp_mb__before_spinlock(); } /* Clearing is done after a TLB flush, which also provides a barrier. */ static inline void clear_tlb_flush_pending(struct mm_struct *mm)
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