"order" is -1 when compacting via /proc/sys/vm/compact_memory. Making
it unsigned causes a bug in __compact_pgdat() when we test:
if (cc->order < 0 || !compaction_deferred(zone, cc->order))
compact_zone(zone, cc);
[akpm@linux-foundation.org: make __compact_pgdat()'s comparison match other code sites] Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Minchan Kim <minchan@kernel.org> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>