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authorMel Gorman <mgorman@suse.de>2013-12-18 17:08:45 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-12-18 19:04:51 -0800
commitaf2c1401e6f9177483be4fad876d0073669df9df (patch)
tree630b024e7f5e53fcd73ab4d04148720185797a0a
parent20841405940e7be0617612d521e206e4b6b325db (diff)
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 <mgorman@suse.de> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/mm_types.h7
1 files changed, 6 insertions, 1 deletions
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index e5c49c30460f..ad0616f2fe2c 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -482,7 +482,12 @@ static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
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)