mm/compaction.c: fix deferring compaction mistake

Commit aff622495c9a ("vmscan: only defer compaction for failed order and
higher") fixed bad deferring policy but made mistake about checking
compact_order_failed in __compact_pgdat().  So it can't update
compact_order_failed with the new order.  This ends up preventing
correct operation of policy deferral.  This patch fixes it.

Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/compaction.c b/mm/compaction.c
index e78cb96..b6984e2 100644 (file)
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -861,7 +861,7 @@ static int __compact_pgdat(pg_data_t *pgdat, struct compact_control *cc)
                if (cc->order > 0) {
                        int ok = zone_watermark_ok(zone, cc->order,
                                                low_wmark_pages(zone), 0, 0);
-                       if (ok && cc->order > zone->compact_order_failed)
+                       if (ok && cc->order >= zone->compact_order_failed)
                                zone->compact_order_failed = cc->order + 1;
                        /* Currently async compaction is never deferred. */
                        else if (!ok && cc->sync)