mm: numa: guarantee that tlb_flush_pending updates are visible before page table updates

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>
This commit is contained in:
Mel Gorman 2013-12-18 17:08:45 -08:00 committed by Greg Kroah-Hartman
parent d303cf4624
commit 5d8e03b254

View file

@ -480,7 +480,12 @@ 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)