mm: migrate: fix barriers around tlb_flush_pending

Reading tlb_flush_pending while the page-table lock is taken does not
require a barrier, since the lock/unlock already acts as a barrier.
Removing the barrier in mm_tlb_flush_pending() to address this issue.

However, migrate_misplaced_transhuge_page() calls mm_tlb_flush_pending()
while the page-table lock is already released, which may present a
problem on architectures with weak memory model (PPC).  To deal with
this case, a new parameter is added to mm_tlb_flush_pending() to
indicate if it is read without the page-table lock taken, and calling
smp_mb__after_unlock_lock() in this case.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Nadav Amit <[email protected]>
Acked-by: Rik van Riel <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jeff Dike <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Nadav Amit <[email protected]>
Cc: Russell King <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Yoshinori Sato <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions