From: Mel Gorman <[email protected]> Subject: mm: numa: guarantee that tlb_flush_pending updates are visible before page table updates
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 <[email protected]> Acked-by: Paul E. McKenney <[email protected]> Reviewed-by: Rik van Riel <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> --- include/linux/mm_types.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff -puN include/linux/mm_types.h~mm-numa-guarantee-that-tlb_flush_pending-updates-are-visible-before-page-table-updates include/linux/mm_types.h --- a/include/linux/mm_types.h~mm-numa-guarantee-that-tlb_flush_pending-updates-are-visible-before-page-table-updates +++ a/include/linux/mm_types.h @@ -482,7 +482,12 @@ 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) _ -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
