mm/compaction: reverse the change that forbade sync migraton with __GFP_NO_KSWAPD
It's uncertain this has been beneficial, so it's safer to undo it. All
other compaction users would still go in synchronous mode if a first
attempt at async compaction failed. Hopefully we don't need to force
special behavior for THP (which is the only __GFP_NO_KSWAPD user so far
and it's the easier to exercise and to be noticeable). This also make
__GFP_NO_KSWAPD return to its original strict semantics specific to bypass
kswapd, as THP allocations have khugepaged for the async THP
allocations/compactions.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Alex Villacis Lasso <avillaci@fiec.espol.edu.ec> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>